Scale, Evolution and Emergence in Food Systems

Christopher Otter diagnoses the impossibility of fully governing large-scale food systems and the novel ecologies they create

Design optimisation of separate-jet exhausts for the next generation of civil aero-engines

This paper presents the development and application of a computational framework for the aerodynamic design of separate-jet exhaust systems for Very-High-Bypass-Ratio (VHBR) gas-turbine aero-engines. An analytical approach is synthesised comprising a series of fundamental modelling methods. These address the aspects of engine performance simulation, parametric geometry definition, viscous/compressible flow solution, design space exploration, and genetic optimisation. Parametric design is carried out based on minimal user-input combined with the cycle data established using a zero-dimensional (0D) engine analysis method. A mathematical approach is developed based on Class-Shape Transformation (CST) functions for the parametric geometry definition of gas-turbine exhaust components such as annular ducts, nozzles, after-bodies, and plugs. This proposed geometry formulation is coupled with an automated mesh generation approach and a Reynolds Averaged Navier–Stokes (RANS) flow-field solution method, thus forming an integrated aerodynamic design tool. A cost-e ective Design Space Exploration (DSE) and optimisation strategy has been structured comprising methods for Design of Experiment (DOE), Response Surface Modelling (RSM), as well as genetic optimisation. The integrated framework has been deployed to optimise the aerodynamic performance of a separate-jet exhaust system for a large civil turbofan engine representative of future architectures. The optimisations carried out suggest the potential to increase the engine’s net propulsive force compared to a baseline architecture, through optimum re-design of the exhaust system. Furthermore, the developed approach is shown to be able to identify and alleviate adverse flow-features that may deteriorate the aerodynamic behaviour of the exhaust system

The stiffess of unsaturated railway formations

The rational design of a substructure to support a rail track requires an estimation of the stiffness value of the formation on which it is to be built. Stiffness values derived from back-analyses of deformations of the ground beneath the track have been found by the authors to be much higher than those predicted from laboratory element testing on saturated specimens. This may be because of differences in compaction between field and laboratory, or because suctions created by lack of saturation play a key role in controlling stiffness, and therefore the performance of the track when in use. To test the latter hypothesis a laboratory study has been carried out on material representative of that found in South African railway formations. This was tested at constant dry density and various water contents, with matric suctions determined using different established techniques, and very-small-strain stiffness levels obtained from resonant column testing. A suction stress characteristic curve was developed to identify the contribution of suction to the overall effective stress for this material. The results show that suction can indeed be an important contributing factor to the magnitude of stiffness. For material tested at constant dry density, the stiffness initially increases with reducing compaction water content, and therefore with increasing suction. It subsequently reduces back towards the saturated value as the compaction water content approaches zero, even though the matric suction continues to increase. The relative increase in very-small-strain stiffness due to suction depends, to a large extent, on the net normal stress during the stiffness measurement. The effect of matric suction is proportionately greatest at the low net normal stress levels that apply for shallow infrastructures such as rail formations. Also, the operational stiffness depends not only on the current water content (and therefore suction), but also on the water content at which the material has been compacted.The Engineering and Physical Sciences Research Council’s ‘Rail Research UK’ programmehttp://pif.sagepub.comhb2016Civil Engineerin

Access to a floating wind turbine

The offshore wind turbine service industry is now well established with a large number of turbines being successfully operated and maintained. A number of methods and technologies are available to allow the safe transfer of service crews to these primarily fixed monopile installations. The most common of these is the bow transfer method which uses a combination of a high friction fender and a large vessel thrust to minimise relative motion between the bow and the turbine foundation. An upcoming challenge for the offshore wind turbine service industry will be the increasing use of floating foundations in far offshore and deep water sites. A number of structures are currently being developed and the first commercial floating wind farm is expected to be commissioned in late 2017. The use of floating structures will make it more difficult to ensure crew safety and comfort during transfer operations as the interaction between two floating bodies needs to be considered. Thus, the bow transfer method used to access fixed foundations may not be suitable for accessing floating turbine platforms. This paper will use a combination of physical and numerical modelling to assess the ability of a wind farm service vessel to maintain contact with a floating offshore wind turbine structure by use of the bow transfer method

Forefoot pathology in rheumatoid arthritis identified with ultrasound may not localise to areas of highest pressure: cohort observations at baseline and twelve months

BackgroundPlantar pressures are commonly used as clinical measures, especially to determine optimum foot orthotic design. In rheumatoid arthritis (RA) high plantar foot pressures have been linked to metatarsophalangeal (MTP) joint radiological erosion scores. However, the sensitivity of foot pressure measurement to soft tissue pathology within the foot is unknown. The aim of this study was to observe plantar foot pressures and forefoot soft tissue pathology in patients who have RA.Methods A total of 114 patients with established RA (1987 ACR criteria) and 50 healthy volunteers were assessed at baseline. All RA participants returned for reassessment at twelve months. Interface foot-shoe plantar pressures were recorded using an F-Scan® system. The presence of forefoot soft tissue pathology was assessed using a DIASUS musculoskeletal ultrasound (US) system. Chi-square analyses and independent t-tests were used to determine statistical differences between baseline and twelve months. Pearson’s correlation coefficient was used to determine interrelationships between soft tissue pathology and foot pressures.ResultsAt baseline, RA patients had a significantly higher peak foot pressures compared to healthy participants and peak pressures were located in the medial aspect of the forefoot in both groups. In contrast, RA participants had US detectable soft tissue pathology in the lateral aspect of the forefoot. Analysis of person specific data suggests that there are considerable variations over time with more than half the RA cohort having unstable presence of US detectable forefoot soft tissue pathology. Findings also indicated that, over time, changes in US detectable soft tissue pathology are out of phase with changes in foot-shoe interface pressures both temporally and spatially.Conclusions We found that US detectable forefoot soft tissue pathology may be unrelated to peak forefoot pressures and suggest that patients with RA may biomechanically adapt to soft tissue forefoot pathology. In addition, we have observed that, in patients with RA, interface foot-shoe pressures and the presence of US detectable forefoot pathology may vary substantially over time. This has implications for clinical strategies that aim to offload peak plantar pressures

Aerodynamic design of separate-jet exhausts for future civil aero engines, Part I: parametric geometry definition and CFD approach

This paper presents the development of an integrated approach which targets the aerodynamic design of separate-jet exhaust systems for future gas-turbine aero-engines. The proposed framework comprises a series of fundamental modeling theories which are applicable to engine performance simulation, parametric geometry definition, viscous/compressible flow solution, and Design Space Exploration (DSE). A mathematical method has been developed based on Class-Shape Transformation (CST) functions for the geometric design of axi-symmetric engines with separate-jet exhausts. Design is carried out based on a set of standard nozzle design parameters along with the flow capacities established from zero-dimensional (0D) cycle analysis. The developed approach has been coupled with an automatic mesh generation and a Reynolds Averaged Navier-Stokes (RANS) flow-field solution method, thus forming a complete aerodynamic design tool for separate-jet exhaust systems. The employed aerodynamic method has initially been validated against experimental measurements conducted on a small-scale Turbine Powered Simulator (TPS) nacelle. The developed tool has been subsequently coupled with a comprehensive DSE method based on Latin- Hypercube Sampling (LHS). The overall framework has been deployed to investigate the design space of two civil aero-engines with separate jet exhausts, representative of current and future architectures, respectively. The inter-relationship between the exhaust systems' thrust and discharge coefficients has been thoroughly quantified. The dominant design variables that affect the aerodynamic performance of both investigated exhaust systems have been determined. A comparative evaluation has been carried out between the optimum exhaust design sub-domains established for each engine. The proposed method enables the aerodynamic design of separate-jet exhaust systems for a designated engine cycle, using only a limited set of intuitive design variables. Furthermore, it enables the quantification and correlation of the aerodynamic behavior of separate-jet exhaust systems for designated civil aero-engine architectures. Therefore, it constitutes an enabling technology towards the identification of the fundamental aerodynamic mechanisms that govern the exhaust system performance for a user-specified engine cycl

The BPT Diagram in Cosmological Galaxy Formation Simulations: Understanding the Physics Driving Offsets at High Redshift

© 2022. The Author(s). Published by the American Astronomical Society This work is licenced under Creative Commons Attribution 4.0 licence. https://creativecommons.org/licenses/by/4.0/The Baldwin, Philips, & Terlevich diagram of [O iii]/Hβ versus [N ii]/Hα (hereafter N2-BPT) has long been used as a tool for classifying galaxies based on the dominant source of ionizing radiation. Recent observations have demonstrated that galaxies at z ∼ 2 reside offset from local galaxies in the N2-BPT space. In this paper, we conduct a series of controlled numerical experiments to understand the potential physical processes driving this offset. We model nebular line emission in a large sample of galaxies, taken from the simba cosmological hydrodynamic galaxy formation simulation, using the cloudy photoionization code to compute the nebular line luminosities from H ii regions. We find that the observed shift toward higher [O iii]/Hβ and [N ii]/Hα values at high redshift arises from sample selection: when we consider only the most massive galaxies M * ∼ 1010–11 M ⊙, the offset naturally appears, due to their high metallicities. We predict that deeper observations that probe lower-mass galaxies will reveal galaxies that lie on a locus comparable to z ∼ 0 observations. Even when accounting for samples-selection effects, we find that there is a subtle mismatch between simulations and observations. To resolve this discrepancy, we investigate the impact of varying ionization parameters, H ii region densities, gas-phase abundance patterns, and increasing radiation field hardness on N2-BPT diagrams. We find that either decreasing the ionization parameter or increasing the N/O ratio of galaxies at fixed O/H can move galaxies along a self-similar arc in N2-BPT space that is occupied by high-redshift galaxies.Peer reviewedFinal Published versio

The role of spirituality in treatment of patients and work of health care workers

Duhovnost kao specifična dimenzija čovjekove osobnosti u medicini je prepoznata tek u posljednjih dvadesetak godina kao važan čimbenik u procesu izlječenja i odnosa zdravstveni djelatnik – bolesnik. U tu su svrhu provedena brojna istraživanja među pacijentima glede njihova religioznog svjetonazora i vjerničke duhovnosti kako bi se proniknulo što dublje i stekle što sveobuhvatnije spoznaje o utjecaju vjere i duhovnosti na ljudsko zdravlje. Kolika je važnost duhovnosti u suvremenoj medicini, posebice psihologiji, svjedoči i činjenica što su mnoge svjetske akademske institucije uvrstile duhovnost u programe redovite izobrazbe zdravstvenih djelatnika. Djelovanje zdravstvenog osoblja temelji se na kvalitetnom međuljudskom odnosu prema bolesnicima o kojima skrbe. Ovaj je odnos obilježen “povjerenjem” čovjeka koji je pogođen bolešću, ali se uzda u “savjest” i stručnost liječnika koji ga liječi i medicinske sestre koja ga njeguje. Ovaj se interpersonalni odnos temelji na pretpostavci da bolesnik nije samo “klinički slučaj”. Odnos, dakle, mora biti mnogo dublji, cjelovitiji, jer nije bolesno samo njegovo tijelo, nego je bolest zahvatila cijelu osobu, sa svim njezinim duševnim i duhovnim komponentama. Upravo zato zdravstveno osoblje treba biti osposobljeno prepoznati i procijeniti duhovne potrebe pacijenta. Dužnost je zdravstvenog djelatnika stvoriti ozračje međusobnog poštovanja kako bi stekao povjerenje bolesnika koji će potom očitovati svoje tegobe i osjećaje pa i duhovne potrebe. Zdravstveni djelatnik treba biti čuvar i služitelj ljudskoga života, što pretpostavlja integralni pristup fenomenu zdravlja i bolesti. Bez obzira na osobno vjersko uvjerenje ili svjetonazor zdravstveni je djelatnik pozvan u svom profesionalnom odnosu prema bolesniku poštivati i zagovarati temeljne moralne vrijednosti: dostojanstvo ljudske osobe i nepovrjedivost ljudskoga života na svim razinama: tjelesnoj, emocionalnoj, društvenoj i duhovnoj. Za liječenje bolesti, dakle, prijeko je potrebno uzeti u obzir ne samo tjelesne, psihološke i društvene, nego i duhovne čimbenike.Spirituality as a specific dimension of human personality has been recognized in medicine not earlier than the last twenty years as an important factor in the healing process and the relationship between the health care worker and patient. For this purpose numerous researches have been carried out among the patients with regard to their religious worldview and spirituality in order to gain a deep and comprehensive understanding of the influence of religion and spirituality on human health. The importance of spirituality in contemporary medicine, especially in psychology, can be seen in the fact that numerous academic institutions in the world have included spirituality in the educational programmes for health care professionals. The activities of health care workers are founded on a good quality relationship to the patients they care for. This relationship is marked by the confidence of the person affected by a disease who believes in the doctor’s conscience and expertise and the nurse’s care. This interpersonal relationship is based on the assumption that the patient is not just a clinical case. Therefore, the relationship should be much deeper and more comprehensive, because not only his body is ill but illness has affected the whole person with his/her mental and spiritual components. That is why health care workers should be qualified to recognize and assess the spiritual needs of the patient. It is the duty of health care workers to create an atmosphere of mutual respect in order to gain the trust of patients who will then manifest their problems and feelings as well as their spiritual needs. The health worker should be a guardian and minister of human life which implies an integral approach to the phenomenon of health and disease. Regardless of personal religious belief or worldview, a health care worker is called in his professional relationship to the patient to respect and advocate the fundamental moral values: human dignity and inviolability of human life at all levels: physical, emotional, social and spiritual. Therefore, in the treatment of diseases it is necessary to take into account not only physical, psychological and social factors, but spiritual factors as well

Women’s experiences of wearing therapeutic footwear in three European countries

Background: Therapeutic footwear is recommended for those people with severe foot problems associated with rheumatoid arthritis (RA). However, it is known that many do not wear them. Although previous European studies have recommended service and footwear design improvements, it is not known if services have improved or if this footwear meets the personal needs of people with RA. As an earlier study found that this footwear has more impact on women than males, this study explores women’s experiences of the process of being provided with it and wearing it. No previous work has compared women’s experiences of this footwear in different countries, therefore this study aimed to explore the potential differences between the UK, the Netherlands and Spain. Method: Women with RA and experience of wearing therapeutic footwear were purposively recruited. Ten women with RA were interviewed in each of the three countries. An interpretive phenomenological approach (IPA) was adopted during data collection and analysis. Conversational style interviews were used to collect the data. Results: Six themes were identified: feet being visibly different because of RA; the referring practitioners’ approach to the patient; the dispensing practitioners’ approach to the patient; the footwear being visible as different to others; footwear influencing social participation; and the women’s wishes for improved footwear services. Despite their nationality, these women revealed that therapeutic footwear invokes emotions of sadness, shame and anger and that it is often the final and symbolic marker of the effects of RA on self perception and their changed lives. This results in severe restriction of important activities, particularly those involving social participation. However, where a patient focussed approach was used, particularly by the practitioners in Spain and the Netherlands, the acceptance of this footwear was much more evident and there was less wastage as a result of the footwear being prescribed and then not worn. In the UK, the women were more likely to passively accept the footwear with the only choice being to reject it once it had been provided. All the women were vocal about what would improve their experiences and this centred on the consultation with both the referring practitioner and the practitioner that provides the footwear. Conclusion: This unique study, carried out in three countries has revealed emotive and personal accounts of what it is like to have an item of clothing replaced with an ‘intervention’. The participant’s experience of their consultations with practitioners has revealed the tension between the practitioners’ requirements and the women’s ‘social’ needs. Practitioners need greater understanding of the social and emotional consequences of using therapeutic footwear as an intervention

Bounds to electron spin qubit variability for scalable CMOS architectures

Spins of electrons in CMOS quantum dots combine exquisite quantum properties and scalable fabrication. In the age of quantum technology, however, the metrics that crowned Si/SiO2 as the microelectronics standard need to be reassessed with respect to their impact upon qubit performance. We chart the spin qubit variability due to the unavoidable atomic-scale roughness of the Si/SiO$_2$ interface, compiling experiments in 12 devices, and developing theoretical tools to analyse these results. Atomistic tight binding and path integral Monte Carlo methods are adapted for describing fluctuations in devices with millions of atoms by directly analysing their wavefunctions and electron paths instead of their energy spectra. We correlate the effect of roughness with the variability in qubit position, deformation, valley splitting, valley phase, spin-orbit coupling and exchange coupling. These variabilities are found to be bounded and lie within the tolerances for scalable architectures for quantum computing as long as robust control methods are incorporated.Comment: 20 pages, 8 figure