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As our planet undergoes both chemical transformations and climate shifts, grasping the fundamental structures of the atmosphere and its interconnectedness with the Earth system is paramount. Here, a system-level approach is indispensable. This approach requires us to understand natural and man-made drivers of chemical change in the atmosphere, not as separate influences or part of an isolated system, but as closely interwoven and interactive processes in the Earth system. As we progress, it is important to cultivate an integrated understanding of atmospheric chemistry that connects across scales, from the microscopic to the global; one that incorporates human actions and potential future scenarios.
This chapter provides a brief historical overview of the origin and evolution of our atmosphere, also examining how its physical structure influences its composition. It also frames seeing the atmosphere as part of a larger Earth system. This will help us to understand in later chapters, for example, Chapters 10 and 11, how processes within Earth’s subsystems interact with and influence one another.
This chapter explores ancient Greek depictions of the force or pressure contained within the person and action of peithō by comparison with anankē (constraint, necessity). Literary and linguistic analyses of passages from Homer, Lysias, Xenophon, and Sappho, re-situate πείθω (to win over) as a causative verb that, while often paired with logos, can also induce compliance through nonverbal means. The chapter specifically explores presentations of peithō’s deceptive and constraining actions as compared with anankē in three fifth-century bce texts: Aeschylus’ Prometheus Bound, a passage from Herodotus’ Histories, and Gorgias’ Encomium of Helen. The juxtaposition of these two daemonic forces foregrounds the unscrupulous yet potentially resistible qualities of peithō’s power and how it operates upon individuals or groups. The chapter includes a brief analysis of texts containing the term peithanankē (winning constraint), to represent a form of menacing diplomatic coercion in military situations.
Illite, a common, layered silicate mineral, widely distributed in topsoil and subsoil, is utilized extensively in textiles, medicines, construction, and agriculture due to its distinctive chemical, physical, and mechanical properties. To understand the electronic structures and mechanical properties of illite better, they were studied under pressures ranging from 0 to 20 GPa using density functional theory (DFT) calculations. At ambient pressure, the calculated lattice constants and typical bond lengths were in good agreement with the experimental data. The lattice constants and volumes decreased with increasing pressure. While most bond lengths contracted under pressure, the O–H bond lengths remained nearly constant. Furthermore, analyses of the total and partial density of states, charge density distribution, and energy band structures revealed only minor variations under high pressure, implying that pressure exerts a limited influence on the electronic structure, and that illite retains its structural stability. The elastic constant, C33, was less than C11 and C22, whereas C66 exceeded C44 and C55 in the pressure range of 0–20 GPa. These results indicated that the (001) plane exhibits weaker resistance to deformation compared with the (010) and (100) planes, while its shear deformation resistance is greater. Also, Young’s modulus, the shear modulus, and the bulk modulus of illite increased with pressure, indicating enhanced resistance to elastic deformation and shear failure. The Poisson ratio also increased with pressure, indicating increased ductility. A decrease in the ratio of shear modulus to bulk modulus (G/B) under higher pressures indicated improved toughness. Moreover, the anisotropy of illite diminished with increasing pressure, implying a reduction in the directional dependence of its shear modulus, Young’s modulus, and bulk modulus. These theoretical calculations provide a microscopic understanding of the behavior of natural illite under pressure and offer valuable fundamental data for practical applications of illite.
We are living in a time when many teachers say they are feeling burnt out, and many others have left the profession altogether. Even new teachers who might start out feeling enthusiastic are likely to leave the profession after a few years. Teachers say the pressures they feel don’t match their view of what teaching is supposed to be all about – caring for, and teaching, children and young people. So, what do teachers do? What does the public (and, for that matter, Hollywood movie producers) think teachers do? This chapter argues that we have a bit of a mismatch between what people outside the profession think, and the experiences of teachers themselves. It also argues that broader changes in education, such as the use of data to govern teachers’ work has created extra pressure on teachers.
The bulk modulus of a crystal is often closely related to the compressibility of its constituent elements, such as cation-centred coordination polyhedra. The compressive behaviour of regular polyhedra with a fixed coordination number was studied thoroughly some decades ago and was found to follow a simple universal rule. However, the compressive behaviour of large cations with irregular and poorly defined coordination polyhedra has not been studied systematically because of methodological challenges and biases. Here, an original approach to defining and analysing polyhedral compressibility is proposed, based on the concepts of effective coordination number (ECoN) and weighted mean bond length. This approach is demonstrated using K+ coordination polyhedra as an example.
The equations of fluid dynamics and energy balance are arrived at from the starting point of the powerful Reynolds transport theorem. After writing down the four conservation laws – mass, energy, linear and angular momentum – their consequences when inserted into the transport equation are revealed, in particular Cauchy’s equations of motion, Navier–Stokes equations and the equation of energy balance. A number of prevalent examples are given, including Stokes’s formulae and the Darcy law. The chapter concludes with the theory of the boundary layer.
Here we begin fluid dynamics with the science of fluids at rest. This includes planetary science aspects of atmospheric and oceanic pressure, the forced and free vortex. Here also are introduced the three basic differential operators: grad, div and curl, which will be used throughout the book.
Edited by
Rebecca Leslie, Royal United Hospitals NHS Foundation Trust, Bath,Emily Johnson, Worcester Acute Hospitals NHS Trust, Worcester,Alex Goodwin, Royal United Hospitals NHS Foundation Trust, Bath,Samuel Nava, Severn Deanery, Bristol
Understanding the principles and implications of pressure measurement is vital in anaesthesia. Here, in a similar structure to previous chapters we outline the basic physical principles of pressure, the variety of ways that it can be measured in clinical practice and the relationships with other physical principles. There is then focussed material on blood pressure measurement, through invasive and non-invasive techniques, on resonance and damping in pressure measurement systems, and on the measurement of intracranial pressure. The chapter finishes by discussing cardiac output measurement in clinical practice.
Edited by
Rebecca Leslie, Royal United Hospitals NHS Foundation Trust, Bath,Emily Johnson, Worcester Acute Hospitals NHS Trust, Worcester,Alex Goodwin, Royal United Hospitals NHS Foundation Trust, Bath,Samuel Nava, Severn Deanery, Bristol
This chapter is focussed on the International Standard of Units (SI) and their relevance to anaesthesia. This is a common exam question and it is important to understand the relationship between base SI units and other derived units. The chapter relates pressure to force, and clarifies the different measures of pressure including how they can be interchanged.
The key question in mechanical ventilation is whether invasive or non-invasive is the option being applied to the individual patient. In order to answer this question, it is necessary to recognize the pathophysiology and understand which physiological system has failed and needs to be supported. In this chapter we outline the optimal treatment options for respiratory insufficiency type 1 and 2. The reader will be made familiar with the basic principles of non-invasive and invasive ventilation. The aim is to arbitrate an overview as well as basic flowchart for the treatments depending on which of the aforementioned respiratory insufficiencies are to be treated. The chapter also comprises a quick guide to the initial ventilator settings.
The current strategic environment can be characterised as a return to great power competition, centred on the Indo-Pacific region, within an environment of post-pandemic climate change. The ’region is in the midst of the most consequential strategic realignment since the Second World War’, and the confluence of these characteristics has resulted in a major step-change for Australia’s strategic policy and has significantly increased expectations of the Australian Defence Force. For the ADF, the force generation and force employment requirements to effectively shape, deter and respond within a ’competitive and contested’ region increase the demand signal on the force. For the Australian Army, accelerated warfare requires land forces ’to be ready to do more tasks, fight at all ranges, and enable the joint force in every domain’.
Manipulation is pervasive in our lives, yet it is not well understood. Specifically, we lack a wide philosophical theory of manipulation. Such a theory will successfully answer two main questions: a question about the precise meaning of “manipulation,” and a question about its moral status. Prior to presenting a novel theory of manipulation in the following chapters, Chapter 1 offers an overview of the state of the art of philosophical thinking on manipulation. The semantic field of manipulation is constructed by three main concepts: rational persuasion, deception, and coercion. Manipulation cannot, however, be understood adequately on the basis of any one of these concepts, and there is no good theory that accounts for manipulation using a combination of them. The chapter reviews the many difficulties left open by notable attempts to provide an account of the concept of manipulation. The criticisms of those attempts raise the deeper suspicion that perhaps manipulation is not to be captured by a definition at all.
ATO4 compounds are a class of oxides which includes the rare earth element (REE) bearing phosphates and arsenates, REEPO4 and REEAsO4. In this study, we have investigated the isothermal high-pressure and the isobaric high-temperature behaviour of natural samples of xenotime-(Y) (ideally YPO4), chernovite-(Y) (YAsO4) and monazite-(Ce) (CePO4) from the hydrothermal veins cropping out at Mt. Cervandone in the Western Italian Alps. Experimental data based on in situ X-ray diffraction (both single-crystal and powder techniques with conventional or synchrotron radiation) have allowed us to fit the unit-cell volumes and axial thermal and compressional evolution and provide a suite of refined thermo-elastic parameters. A comprehensive analysis of the role played by the crystal chemistry on the thermo-elastic response of these minerals is discussed, along with the description of the main crystal-structural deformation mechanisms for both the zircon (xenotime and chernovite) and monazite (monazite) structural types. Pressure-induced phase transitions of xenotime-(Y) and chernovite-(Y) are discussed and compared with previous literature data, whereas a change in the compressional behaviour of monazite-(Ce) at ∼18 GPa, involving an increase in the coordination number of the REE-hosting A site, is presented and discussed.
Half of all mental health problems start by the age of 15 and the teenage and young adult years are particularly difficult for girls with high and increasing rates of anxiety, depression and self-harm. Many different factors contribute, including social media, peer pressures, focus on appearance, friends, relationships, schoolwork and, as Everyone’s Invited has recently highlighted, personal safety. There is tremendous pressure to conform with the expectations of others. Attitudes to women and girls seem to have gone into reverse during the author’s lifetime. It is too simplistic to view the problems of young women as a simply a ‘lack of self-esteem’. The difficulties they face in society are consistently underestimated and not taken seriously. Fast access to therapy is crucial. Bullying must be addressed effectively. Sexist and mysogynistic attitudes in school must be challenged and, given the easy access now to pornography, the issues of consent should addressed head on by both parents and schools. Using the example of Everyone’s Invited, women and girls need to reach out and support each other. The personal is still political.
Of the two parallel lives, it is Hannibal who used an elected position to carry through political and economic reforms unwelcome to the ruling oligarchy, whereas Scipio was quiet and accepting of the status quo. A story that Hannibal was prosecuted after Zama is not believable. He urged acceptance of the peace terms after Zama, manhandling an opposing speaker; he apologized for this, pleading long absence from civil life. As elected ‘praetor’ (sufete), he antagonized powerful citizens. His summons of a ‘quaestor’ (financial official) was refused. Scipio, soon after, also had trouble with a recalcitrant quaestor. Hannibal’s main political reform was to end life tenure of the ‘judges’. Economically, perhaps using skills developed when managing the logistics of his Italian campaign, he calculated Carthage’s revenues and ended embezzlement. The unpopularity with the ruling class so generated, and Roman diplomatic pressure, caused him to flee permanently. Carthage’s second-century economy is evaluated.
The NHS, the great survivor of the post-war consensus, faced a period of considerable uncertainty. This chapter will examine if, and how, the Conservatives have changed the NHS in the face of economic pressures, technological advances, demographic change, changing expectations and the pandemic. Any analysis of the health policy of a government is incomplete without examining the wider state of social care and its relation to healthcare policy.
There are many different varieties of automatic weather stations (AWSs) available, and a huge range of different applications for them. This chapter suggests a structured approach to specifying AWS features to meet any particular requirement, provides a short guide to AWS products and services available (from consumer brands to sophisticated professional systems capable of unattended operation in remote areas) and offers guidance in selecting one or more options from the multiplicity of product offerings on the market.
The osmotic swelling of an n-butylammonium vermiculite in a 0.1 M solution of n-butylammonium chloride has been studied as a function of temperature and hydrostatic pressure by neutron diffraction. On application of a pressure of 1050 bar the vermiculite swelled macroscopically at 20°C, the c-axis spacing changing from 19.4 to 126 Å. The phase transition was completely reversible with respect to both pressure and temperature, and a complete study of the temperature-pressure phase diagram was made at pressures as high as 2000 bar. The heat capacity change with temperature across the swelling transition was measured at atmospheric pressure, and the enthalpy and entropy of the change from crystalline to osmotic phases were found to be, respectively, 5.2 J/g and 0.0183 J/K·g of dry clay. The combination of the entropy change with the gradient of the pressure-temperature phase boundary gave the volume change accompanying the transition. The total volume of the swollen phase was less than that of the crystalline phase plus the appropriate amount of solution, corresponding to a fractional decrease of about 0.1% in the water volume from bulk solution to between the plates.
The dehydration temperature of K-montmorillonite, obtained by ion exchange of a Na-mont-morillonite, was determined at pressures to 2 kbar, using high-pressure differential thermal analysis. Dehydration reactions were found at about 50° and 100°C above the liquid-vapor curve of water. At pressures above the critical point of water the dehydration temperatures increased only slightly. The temperature of the first dehydration reaction is 10°C higher than for Na-montmorillonite, indicating a slightly greater stability of the hydration shell around the potassium interlayer cation. The second dehydration reaction occurs at a slightly lower temperature. The data were used to determine the enthalpy of the dehydration ΔH(dh) and the bonding enthalpy of the interlayer water ΔH(iw) at 1 atm. The first dehydration reaction of the K-exchanged montmorillonite has a ΔH(dh) = 46.16 ± 0.06 kJ/mole and a ΔH(iw) = 7.8 ± 0.5 kJ/mole, whereas for the second reaction, ΔH(dh) = 56.7 ± 2 kJ/mole and ΔH(iw) = 19.8 ± 2 kJ/mole. These values compare with a ΔH(dh) = 46.8 ± 0.3 kJ/mole and a ΔH(iw) = 7.8 ± 0.5 kJ/mole for the first dehydration reaction of the Na-montmorillonite and a ΔH(dh) = 62.9 ± 2 kJ/mole and ΔH(iw) = 27.1 ± 2 kJ/mole for the second dehydration.
A high-pressure, high-temperature cell was used to monitor the basal X-ray powder diffraction spacing of Na-saturated Cheto montmorillonite in contact with NaCl solutions at temperatures as high as 200°C and hydraulic pressures as high as 6700 psi (456 bar). The 003 and 005 reflections were used to determine d(001) of the smectite. The montmorillonite, in 1 molal NaCl, exhibited a d(001) of 15.4 Å at room temperature and pressure and a d(001) of 15.6–15.7 Å under 500–2200 psi hydraulic pressure. The basal spacing of the clay in 5 molal NaCl was 15.2 Å and 15.33–15.45 Å at 1 bar and 750–6700 psi (53–456 bar), respectively. Because no changes in the basal spacing with increasing temperature to 200°C were detected in any of the experiments, this Na-smectite probably exists as a two-water-layer complex under diagenetic conditions.