228 research outputs found

    A High-Speed Numerical Analysis Technique for Millimetre Wave Aperture Antennae

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    By use of the geometrical theory of optics the radiation characteristics of a WGM antenna have already been investigated and designed. In order to improve the accuracy of the present calculation it was necessary to account for diffraction. Since the conventional method based on Kirchhoff-Huygens principle requires much computational time and memory, a numerical analysis method has been developed to overcome such a difficulty, i.e. the antenna aperture is subdivided into a series of subapertures of small area so that the field amplitude can be assumed uniform with the phase either uniform or linearly changing. The radiation fields from the subapertures are evaluated by use of an appropriate analytical solution. The radiated field pattern of the aperture is subsequently obtained by summing the radiation contributions from each of the subapertures in turn. Results from the most recent WGM calculations will be presented

    Towards a circular economy: insights based on the development of the global ENGAGE-materials model and evidence for the iron and steel industry

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    A number of recent economic modelling studies have attempted to analyse resource efficiency and the circular economy. However, modelling analysis in this area is relatively underdeveloped. In particular, many CGE models are unable to provide significant insight given their aggregated sectoral coverage. Here we describe the development of the Environmental Global Applied General Equilibrium (ENGAGEmaterials) model created to consider the economic and sectoral effects of potential policies on a circular economy and resource efficiency, which affect materials and resources at the stages of extraction, production and recycling. Our policy scope is global with a special emphasis on China and Europe, as both regions have dedicated policies in place and indicate their willingness to take the lead. The case of steel is relevant as it is a key material for all economies across the world and offers a range of interesting features for circularity and sustainability. ENGAGE-materials models iron ore mining, primary production of iron and steel, secondary production of iron and steel, and steel scrap recycling at the global level. We utilise this technology rich framework to provide preliminary results on scenarios comprising economic insights into a saturation effect and straightforward policy such as doubling the availability of secondary steel

    Steel in a circular economy: global implications of a green shift in China

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    China is increasingly known for its ambitions towards an ‘ecological civilisation’ and a circular economy. Our article assesses the implications of an accelerated shift towards steel recycling in China. Given the relevance of steel for development worldwide as well as its environmental intensity, any such shift is likely to have implications for competitiveness in China and beyond. Recent findings suggest that China could take advantage of an increasing availability of obsolete steel scrap in the coming decades, moving towards more circular, and potentially greener, steel production. We assess such industrial restructuring from an economic perspective and address the competitiveness of China relative to other developing and industrialised regions. The analysis uses a novel global economy-wide modelling framework (ENGAGE-materials) to assess the aggregate and sector-level impacts of different scrap use options in China in the 2019–2030 time frame. The results show moderate GDP gains for China of cumulated USD 589 billion in GDP gains by 2030 despite a replacement of primary steel capacity. A more comprehensive industrial policy mix aimed at improved recycling practices and more adaptive downstream sectors could increase gains to USD 819 billion. The international implications are mixed, with losses for iron ore producers (Australia, Brazil and India) and gains for most developing countries benefiting from lower steel prices. Another result is an increasing demand for coal in electricity production if such a shift wouldn’t be aligned with an accelerated energy transition towards low carbon pathways. We discuss policy implications of such alignment, potential co-benefits, and a need for green international partnerships

    Extrapolation or saturation – revisiting growth patterns, development stages and decoupling

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    The contemporary debate considering the use of natural resources in economic growth centres around the concept of ‘decoupling’ driven through improvements in resource efficiency. Many studies extrapolate future demand from a short time series of previous years. However, we believe there should be greater attention on the underlying demand assumptions and the possibility of long-term changes. Accordingly, this paper is concerned with a potential saturation in material use as a result of countries moving through stages of development over decades from early industrialisation, over mass production and into a mature stage. An observation of such saturation is relevant for global environmental change as future demand for resources could be lower than currently expected, leading to less associated environmental pressures. In particular, emerging economies are undergoing changing growth patterns, and their future resource use may be significantly lower than contemporary analysis suggests. This paper combines the analytical strands of resource economics and material flow analysis. It investigates both material-specific demand and stock build-up trends over an extended time horizon of a century. Four materials (steel, cement, aluminium and copper) are analysed applying an indicator called ‘Apparent Domestic Consumption’ (ADC) and using international trade data for four industrialised countries (Germany, Japan, UK, USA) together with China as the most preeminent emerging economy. Our results confirm the occurrence of a saturation effect for most materials considered. While the evidence is strong for the per capita apparent consumption of steel, copper and cement in the four industrialised countries, it is somewhat weaker for aluminium. Also, such saturation in material use can start at different income levels, with the saturation beginning to occur relatively early for steel and cement (12,000GDP/capita)andlaterforcopper(12,000 GDP/capita) and later for copper (20,000 GDP/capita). The results suggest a time gap of around thirty+ years from the take-off of large-scale adoption of one type of material and any saturation occurring. We also shed light on the build-up of stocks in the economy, where our findings suggest there is a delayed saturation of at least twenty years compared to apparent consumption depending on the lifetimes of capital goods. With regard to China, a demand saturation for steel and copper has already started to occur, and our analysis suggests such saturation will soon take place for cement. These findings provide a more moderate outlook on China’s future material demand compared to an extrapolation of recent dynamics. Our new insights on the nexus between economic growth, development stages and the use of natural resources have implications for the decoupling debate and for investments into commodities. From a wider environmental policy perspective, one may expect China and other emerging economies to achieve a saturation effect soon and therefore also peak their industrial emissions of greenhouse gases, supporting the nationally determined contribution (NDC) to the Paris Agreement on Climate Change

    The hypoxia-regulated ectonucleotidase CD73 is a host determinant of HIV latency

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    Deciphering the mechanisms underlying viral persistence is critical to achieving a cure for human immunodeficiency virus (HIV) infection. Here, we implement a systems approach to discover molecular signatures of HIV latently infected CD4+ T cells, identifying the immunosuppressive, adenosine-producing ectonucleotidase CD73 as a key surface marker of latent cells. Hypoxic conditioning, reflecting the lymphoid tissue microenvironment, increases the frequency of CD73+ CD4+ T cells and promotes HIV latency. Transcriptomic profiles of CD73+ CD4+ T cells favor viral quiescence, immune evasion, and cell survival. CD73+ CD4+ T cells are capable of harboring a functional HIV reservoir and reinitiating productive infection ex vivo. CD73 or adenosine receptor blockade facilitates latent HIV reactivation in vitro, mechanistically linking adenosine signaling to viral quiescence. Finally, tissue imaging of lymph nodes from HIV-infected individuals on antiretroviral therapy reveals spatial association between CD73 expression and HIV persistence in vivo. Our findings warrant development of HIV-cure strategies targeting the hypoxia-CD73-adenosine axis

    Therapeutic benefits of proning to improve pulmonary gas exchange in severe respiratory failure: Focus on fundamentals of physiology

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    NEW FINDINGS: What is the topic of this review? The use of proning for improving pulmonary gas exchange in critically ill patients. What advances does it highlight? Proning places the lung in its ‘natural’ posture, and thus optimises the ventilation‐perfusion distribution, which enables lung protective ventilation and the alleviation of potentially life‐threatening hypoxaemia in COVID‐19 and other types of critical illness with respiratory failure. ABSTRACT: The survival benefit of proning patients with acute respiratory distress syndrome (ARDS) is well established and has recently been found to improve pulmonary gas exchange in patients with COVID‐19‐associated ARDS (CARDS). This review outlines the physiological implications of transitioning from supine to prone on alveolar ventilation‐perfusion ([Formula: see text]) relationships during spontaneous breathing and during general anaesthesia in the healthy state, as well as during invasive mechanical ventilation in patients with ARDS and CARDS. Spontaneously breathing, awake healthy individuals maintain a small vertical (ventral‐to‐dorsal) [Formula: see text] ratio gradient in the supine position, which is largely neutralised in the prone position, mainly through redistribution of perfusion. In anaesthetised and mechanically ventilated healthy individuals, a vertical [Formula: see text] ratio gradient is present in both postures, but with better [Formula: see text] matching in the prone position. In ARDS and CARDS, the vertical [Formula: see text] ratio gradient in the supine position becomes larger, with intrapulmonary shunting in gravitationally dependent lung regions due to compression atelectasis of the dorsal lung. This is counteracted by proning, mainly through a more homogeneous distribution of ventilation combined with a largely unaffected high perfusion dorsally, and a consequent substantial improvement in arterial oxygenation. The data regarding proning as a therapy in patients with CARDS is still limited and whether the associated improvement in arterial oxygenation translates to a survival benefit remains unknown. Proning is nonetheless an attractive and lung protective manoeuvre with the potential benefit of improving life‐threatening hypoxaemia in patients with ARDS and CARDS

    The Role of Whole Blood Impedance Aggregometry and Its Utilisation in the Diagnosis and Prognosis of Patients with Systemic Inflammatory Response Syndrome and Sepsis in Acute Critical Illness

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    Objective: To assess the prognostic and diagnostic value of whole blood impedance aggregometry in patients with sepsis and SIRS and to compare with whole blood parameters (platelet count, haemoglobin, haematocrit and white cell count). Methods: We performed an observational, prospective study in the acute setting. Platelet function was determined using whole blood impedance aggregometry (multiplate) on admission to the Emergency Department or Intensive Care Unit and at 6 and 24 hours post admission. Platelet count, haemoglobin, haematocrit and white cell count were also determined. Results: 106 adult patients that met SIRS and sepsis criteria were included. Platelet aggregation was significantly reduced in patients with severe sepsis/septic shock when compared to SIRS/uncomplicated sepsis (ADP: 90.7±37.6 vs 61.4±40.6; p<0.001, Arachadonic Acid 99.9±48.3 vs 66.3±50.2; p = 0.001, Collagen 102.6±33.0 vs 79.1±38.8; p = 0.001; SD ± mean)). Furthermore platelet aggregation was significantly reduced in the 28 day mortality group when compared with the survival group (Arachadonic Acid 58.8±47.7 vs 91.1±50.9; p<0.05, Collagen 36.6±36.6 vs 98.0±35.1; p = 0.001; SD ± mean)). However haemoglobin, haematocrit and platelet count were more effective at distinguishing between subgroups and were equally effective indicators of prognosis. Significant positive correlations were observed between whole blood impedance aggregometry and platelet count (ADP 0.588 p<0.0001, Arachadonic Acid 0.611 p<0.0001, Collagen 0.599 p<0.0001 (Pearson correlation)). Conclusions: Reduced platelet aggregometry responses were not only significantly associated with morbidity and mortality in sepsis and SIRS patients, but also correlated with the different pathological groups. Whole blood aggregometry significantly correlated with platelet count, however, when we adjust for the different groups we investigated, the effect of platelet count appears to be non-significant

    Исследование закономерностей модификации стали 12Х18Н10Т высокоинтенсивной имплантацией ионов азота

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    В данной работе представлены результаты по изучению формирования пучков ионов азота и их воздействие на поверхность стали 12Х18Н10Т в условиях компенсации распыления. Также было изучено формирование высокоинтенсивных пучков ионов титана. Впервые описан метод измерения глубины легированной примеси при помощи прибора CALOTEST.This paper presents the results of studying the formation of nitrogen ion beams and their effect on the surface of 12X18H10T steel under conditions of sputtering compensation. The formation of high-intensity beams of titanium ions was also studied. For the first time, a method for measuring the depth of an alloyed impurity using the CALOTEST device is described

    Corrosion challenges towards a sustainable society

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    A global transition towards more sustainable, affordable and reliable energy systems is being stimulated by the Paris Agreement and the United Nation's 2030 Agenda for Sustainable Development. This poses a challenge for the corrosion industry, as building climate-resilient energy systems and infrastructures brings with it a long-term direction, so as a result the long-term behaviour of structural materials (mainly metals and alloys) becomes a major prospect. With this in mind "Corrosion Challenges Towards a Sustainable Society" presents a series of cases showing the importance of corrosion protection of metals and alloys in the development of energy production to further understand the science of corrosion, and bring the need for research and the consequences of corrosion into public and political focus. This includes emphasis on the limitation of greenhouse gas emissions, on the lifetime of infrastructures, implants, cultural heritage artefacts, and a variety of other topics
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