Concept and Demonstration of a Coaxial Magnetic Coupling with Electromagnetic Disconnection for Aircraft Permanent Magnet Generators

The application of more electrified systems in aircraft is required to achieve the target of a more sustainable aviation industry. This in turn relies on the development of new electro-mechanical devices to ensure reliability of critical aircraft functions during flight. The aim of this work is to develop and test a device capable of protecting permanent magnet generators from damage, thus enabling the practical use of such high power density generators in aircraft while eliminating their inherent vulnerability to sustained electrical faults. A novel electromechanical actuator concept for decoupling a permanent magnetic generator from an aircraft gas turbine engine is introduced and experimentally validated. The proposed concept combines a coaxial magnetic coupling with an electromagnetic actuator, allowing for rapid disconnection in case of electrical fault detection. The 2D finite element magnetic analysis methodology employed in the design of the magnetic coupling and electromagnetic actuator is validated with experiments that reveal the peak torque results of the magnetic coupling are accurate to within a 2.5% error and the actuator can produce the 450 N pull force required for disconnection. The device is capable of operating at a maximum speed of 12,000 RPM and transmitting a load of 32 Nm

Longitudinal characterisation of haematological and biochemical parameters in cancer patients prior to and during COVID-19 reveals features associated with outcome

Background Cancer patients are at increased risk of death from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Cancer and its treatment affect many haematological and biochemical parameters, therefore we analysed these prior to and during coronavirus disease 2019 (COVID-19) and correlated them with outcome. Patients and methods Consecutive patients with cancer testing positive for SARS-CoV-2 in centres throughout the United Kingdom were identified and entered into a database following local governance approval. Clinical and longitudinal laboratory data were extracted from patient records. Data were analysed using Mann–Whitney U test, Fisher's exact test, Wilcoxon signed rank test, logistic regression, or linear regression for outcomes. Hierarchical clustering of heatmaps was performed using Ward's method. Results In total, 302 patients were included in three cohorts: Manchester (n = 67), Liverpool (n = 62), and UK (n = 173). In the entire cohort (N = 302), median age was 69 (range 19-93 years), including 163 males and 139 females; of these, 216 were diagnosed with a solid tumour and 86 with a haematological cancer. Preinfection lymphopaenia, neutropaenia and lactate dehydrogenase (LDH) were not associated with oxygen requirement (O2) or death. Lymphocyte count (P < 0.001), platelet count (P = 0.03), LDH (P < 0.0001) and albumin (P < 0.0001) significantly changed from preinfection to during infection. High rather than low neutrophils at day 0 (P = 0.007), higher maximal neutrophils during COVID-19 (P = 0.026) and higher neutrophil-to-lymphocyte ratio (NLR; P = 0.01) were associated with death. In multivariable analysis, age (P = 0.002), haematological cancer (P = 0.034), C-reactive protein (P = 0.004), NLR (P = 0.036) and albumin (P = 0.02) at day 0 were significant predictors of death. In the Manchester/Liverpool cohort 30 patients have restarted therapy following COVID-19, with no additional complications requiring readmission. Conclusion Preinfection biochemical/haematological parameters were not associated with worse outcome in cancer patients. Restarting treatment following COVID-19 was not associated with additional complications. Neutropaenia due to cancer/treatment is not associated with COVID-19 mortality. Cancer therapy, particularly in patients with solid tumours, need not be delayed or omitted due to concerns that treatment itself increases COVID-19 severity

Mathematical Models of Aqueous Production, Flow and Drainage

The aqueous humour (AH) is a transparent fluid with water-like properties that fills the anterior chamber (AC, the region between the cornea and the iris) and the posterior chamber (PC, the region between the iris and the lens) of the eye, which are connected at the pupil. AH is produced at ciliary processes, and it flows from the PC to the AC, where it is drained in the trabecular meshwork. AH flow is important physiologically, as it governs intraocular pressure and delivers nutrients to avascular ocular tissues. Disruption of AH flow may lead to multiple pathological conditions, such as glaucoma and nutrient depletion. Studying aqueous production, flow and drainage is thus relevant to understand eye physiology and pathophysiology. Mathematical modelling has proven to be a very useful tool for studying AH, as it allows one to understand the mechanisms of the flow by studying them separately. In this chapter we outline the mathematical models of AH production, different AH flow mechanisms and drainage, subsequently. We focus on analytical works and briefly mention the main conclusions of numerical ones

Hemispheric Differences in the Annual Cycle of Tropical Lower Stratosphere Transport and Tracers

Transport in the tropical lower stratosphere plays a major role in determining the composition of the entire stratosphere. Previous studies that quantified the relative role of transport processes have generally assumed well-mixed tropics and focused on tropical-wide average characteristics. However, it has recently been shown that there is a hemispheric difference in the annual cycle of tropical lower stratosphere ozone and other tracers, with a larger amplitude in the northern tropics (NT) than in the southern tropics (ST). In this study, we examined the ability of chemistry climate models (CCMs) to reproduce the hemispheric differences in ozone (O3) and other tracers (i.e., hydrochloric acid, or HCl and nitrous oxide, or N2O), and then use the CCMs to examine the cause of these differences. Examination of CCM simulations from the CCMVal-2 project shows that the majority of the CCMs produce the observed feature of a larger annual cycle in the NT than ST O3 and other tracers. However, only around a third of the models produce an ozone annual cycle similar to that observed. Transformed Eulerian Mean analysis of two of the CCMs shows that seasonality in vertical advection drives the seasonality in ST O3 and N2O while seasonality of horizontal mixing drives the seasonality in NT O3 and N2O, with a large increase in horizontal mixing during northern summer (associated with the Asian monsoon). Thus, latitudinal and longitudinal variations within the tropics have to be considered to fully understand the balance between transport processes in tropical lower stratosphere

Can imperial radio be transnational? British‐affiliated Arabic radio broadcasting in the interwar period

This media history article uses the development of the British Broadcasting Corporation\u27s Arabic radio broadcasting service in 1938 as a case study for considering the intersections and overlaps between transnationalism and imperialism in the early mid-20th century. Archival evidence suggests that the British Broadcasting Corporation\u27s Arabic broadcasting service, which was based in London, relied for human resources, programming, and other forms of expertise on the Palestine Broadcasting Service in Jerusalem and the Egyptian State Broadcasting Service in Cairo—as well as on British government officials in those countries. Yet scholarly literature on these stations tends to treat them as free-standing institutions with minimal interaction. How might recent scholarship on entangled media histories productively problematize the treatment of radio histories as institutional histories within nation-state boundaries? How might it capture both the transnational and the colonial or imperial connections of these stations? It closes by suggesting how this case study might be useful for scholars working in other arenas