Wave Energy

Part of the immense solar energy input to the earth is converted by natural processes into energy associated with ocean waves. The geographical location of the United Kingdom renders it one of the world ' s most favoured countries with respect to the potential availability of wave energy. In principle. the waves reaching our coastal waters from the North Atlantic might satisfy a considerable fraction of our electricity demand provided that reasonably high overall conversion efficiencies can be achieved . Inventors have recognised the power of the sea for many decades. and there has been no lack of ideas on how it might be tapped . But none of the ideas was developed on a substantial scale. since ample and relatively cheap supplies of other resources were always available . In recent years. however. there has been a growing recognition that--on a world scale-the presently used forms of energy may become too expensive,. too scarce or otherwise unavailable to meet our energy needs by themselves . The Government's responsibility is to ensure that as wide a range as possible of energy supply options are available when they may be needed . Research and development can provide the necessary technical and econom i c data on which the ultimate choices can be made . Within this context. the Government announced in 197 6 the start of an R and D programme on wave energy for which the first phase was to be a feasibility study lasting for two years. The funding level has been increased twice since that time to maintain the momentum of the programme in the light of technical progress . The programme has had three main components: -exploratory deve lopment of several different engineering concepts of wave energy converter; -supporting research in relevant engineering and scientific areas : • the collection and analysis of wave data. • analysis of the structural response to wave-induced motions. • mooring. • energy conversion and transm issi on. • environmental aspects ; -working up preliminary reference designs of full scale stations for tech nical and economic appraisal. The purpose of this paper is to review the present state of knowledge of wave energy in the light of the achievements of the first two-year phase of the programme . Development of the converters Four potential designs of converter were adopted for initial study. since the sparse data available were insufficient to enable a single concept to be chosen with confidence. Proposals for alternative concepts are received on a continuing basis and are assessed against a number of criteria: two of them have so far been added to the programme in order to explore new principles Apart from the basic technical differences the six designs differ from each other in their degree of complexity and their state of development. as described in Chapter 3 . Work on two of the designs has been advanced from laboratory wave tanks to the testing of 1 / 1 0th scale models in natural open water at Loch Ness and in the Solent. For all the designs . a combination of theoretical studies. laboratory work and engineering appraisal has clarified the factors which will prove to be the most crucial in determining which of them could be chosen for more extensive development. The programme has progressed from establishing the scientific feasibility of wave energy converters to confirming the engineering feasibility of designing and building some of the designs . In very broad terms: -the early part of the programme placed considerable emphasis on optimising the efficiency of extraction of the wave energy and proving the scientific feasibility ; -the present stage is concerned with the technical viability and is identifying the main cost centres in the designs . which can then be tackled by further R and D; -the immediate future must also place emphasis not only on the problems of construction . operation and maintenance. and on ways in which unit costs may be reduced . but also on the ability to survive in the most severe wave conditions . Whilst the technical feasibility of some types of converter has been established, we are far from the stage of recommending that a full scale generating station should be built . Of the four original concepts. no single design has yet emerged which is outstandingly better than the other designs when all factors are taken into account . The designs have changed considerably in the course of the feasibility study. and a continuing process of evol ution can be expected as in the early stages of any technical development programme. The optimum design may emerge from further changes in one of the original concepts. from a synthesis of ideas or from an alternative concept . The wave energy is distributed over a wide frequency and energy bandwidth and no des ign has yet been optimised to operate at or near peak efficiency over the whole spectrum. However, one of the new concepts introduced into the programme recently may offer significant advantages in this respect. Supporting research The extent of the available data on waves in the sea areas of primary interest is inadequate as yet for the full assessment of the resource . A start has been made in collecting and analysing new data. which will take several years to reach a satisfactory level. The results so far confirm the general point that the locations around the United Kingdom with the most abundant wave energy lie to the west of the Outer Hebrides, where several hundred km of searoom are available with average annual power levels in the range 35-60 kW / m of wavefront. The majority of the designs un der consideration are free-floating and the converters would operate on or near the water surface-- one of the most hostile environments for engineering structures . The ult imate feasibility. technical and economic . of all designs of floating converter will depend upon extensive further work on mooring and anchoring . Whilst over-designed mooring systems based on present knowledge have allowed the open water trials to proceed with the objective of gaining experience . the existing knowledge is not adequate to design cost-effective mooring systems which will ensure survival at full scale under storm conditions . Considerable progress has been made in assessing and under3tanding suitable energy conversion and transmission systems for the various designs of converter , but much more remains to be done to arrive at the most cost-effective solutions . The general engineering difficulties are quite basic and are related to the properties of the natural wave spectrum : -the conversion system must be able to handle large short-term variations in the instantaneous power level ; -the peak power level in the sea (of the order of 10,OOO kW /m) can be many times greater than the average power level (a few tens of kW / m) ; -the primary output is not in a form which can be handled conventionally (it is . of course . variable with time in a complex way). Moreover. apart from the randomness. other general problems arise from the low energy density of the input and the relatively low speeds and frequency of movement induced by the waves . Engineering devices to transmit large amounts of energy under such conditions must themselves be large. heavy and expensive . The efficient generation of electricity requires machinery operating at relatively high and preferably constant speed . The transition from the one regime to the other appears to be more straightforward for systems involving air turbines than for those which do not: some designs of converter may prove to be intractable in this respect. Many possible forms of energy transmission to the mainland have been reviewed . as summarised in Chapter 6 . Whilst it has been recommended that several options should be kept open in the continuing studies it is likely that most attention will be given to electricity. The overall flow of energy from the waves to a final user connected to the electricity grid involves many separate steps . each of which can involve loss of some of the energy . This can have a considerable influence on the system economics and further work in this area will need to concentrate on both reducing the number of steps and increasing the efficiency (including the directional efficiency of t he converters themselves ) of those which must remain . Unless this can be achieved the usable resource will be only a small proportion of our needs : some pointers to substantial improvements are beginning to emerge. Environmental studies have not revealed any major detrimental effects of the converters provided they are well offshore. More information is needed on the behaviour of salmon and herring off the Outer Hebrides to confirm that the fisheries would not be affected significantly by the widespread installation of converters. Concluding remarks: The costing studies of the reference designs which have been evolved so far indicate that wave-produced electricity is likely to be expensive compared with either nuclear or fossil fuels unless some major breakthrough in the engineering can be achieved . However . this does not imply that the possibility of wave energy should be abandoned at this stage . It must be emphasised that the subject is still at a very ear ly state of development and many unknown factors remain to be resolved . Under these circumstances, wave energy is best regarded at present as a possible insurance technology- the consequences of failure of one of our existing major energy supplies are so severe that it is worth paying an insurance premium to explore fully the alternatives . Nevertheless. the evidence from the feasibility study so far does not allow a recommendation for a full-scale development programme to be made at this time . Much more can be achieved to explore and then to narrow the design choices by continuing work at about the 1 / 1 0th scale coupled with . on the one hand . limited trials of some critical components at larger scale and . on the other hand . f urther creative engineering on the drawing board and laboratory work in a new generation of wave tanks (of which the forerunner has been successfully commissioned at Edinburgh University). The programme has generated a broad basis of knowledge of all aspects of wave energy which did not exist before. so that we can now identify clearly the critical problems to be tackled by further work

Teaching and Learning of Calculus

This survey focuses on the main trends in the field of calculus education. Despite their variety, the findings reveal a cornerstone issue that is strongly linked to the formalism of calculus concepts and to the difficulties it generates in the learning and teaching process. As a complement to the main text, an extended bibliography with some of the most important references on this topic is included. Since the diversity of the research in the field makes it difficult to produce an exhaustive state-of-the-art summary, the authors discuss recent developments that go beyond this survey and put forward new research questions

Legitimacy, Visibility, and the Antecedents of Corporate Social Performance: An Investigation of the Instrumental Perspective

Using institutional theory as the foundation, this study examines the role of organizational visibility from a variety of sources (i.e., slack visibility, industry visibility, and visibility to multiple stakeholders) in influencing corporate social performance (CSP). The conceptual framework offers important insights regarding the instrumental motives of managers in performing CSP initiatives. Based on a sample of 124 S&P 500 firms, the authors found that it is a firm’s visibility to stakeholders, rather than its economic performance, that has the larger impact on managers’ decisions regarding how much CSP their firms exhibit. The results show that more profitable firms may not be motivated to engage actively in CSP unless they are under greater scrutiny by various firm stakeholders. The authors also found that organizational slack (estimated as cost of capital) is positively associated with a Social CSP dimension but negatively associated with a Strategic CSP dimension. This research contributes to the current CSP literature by demonstrating that motivations in addition to normative or ethical ones may be at play in the decisions firms make regarding their CSP.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Acute health risks related to the presence of cyanogenic glycosides in raw apricot kernels and products derived from raw apricot kernels

Amygdalin is the major cyanogenic glycoside present in apricot kernels and is degraded to cyanide by chewing or grinding. Cyanide is of high acute toxicity in humans. The lethal dose is reported to be 0.5\u20133.5 mg/kg body weight (bw). An acute reference dose (ARfD) of 20 lg/kg bw was derived from an exposure of 0.105 mg/kg bw associated with a non-toxic blood cyanide level of 20 micro mol (lM), and applying an uncertainty factor of 1.5 to account for toxicokinetic and of 3.16 to account for toxicodynamic inter-individual differences. In the absence of consumption data and thus using highest intakes of kernels promoted (10 and 60 kernels/day for the general population and cancer patients, respectively), exposures exceeded the ARfD 17\u2013413 and 3\u201371 times in toddlers and adults, respectively. The estimated maximum quantity of apricot kernels (or raw apricot material) that can be consumed without exceeding the ARfD is 0.06 and 0.37 g in toddlers and adults, respectively. Thus the ARfD would be exceeded already by consumption of one small kernel in toddlers, while adults could consume three small kernels. However, consumption of less than half of a large kernel could already exceed the ARfD in adults

Effect of Catheter Dwell Time on Risk of Central Line-Associated Bloodstream Infection in Infants

Central venous catheters in the NICU are associated with significant morbidity and mortality because of the risk of central line–associated bloodstream infections (CLABSIs). The purpose of this study was to determine the effect of catheter dwell time on risk of CLABSI

How do parents manage irritability, challenging behavior, non-compliance and anxiety in children with Autism Spectrum Disorders? A meta-synthesis

Although there is increasing research interest in the parenting of children with ASD, at present, little is known about everyday strategies used to manage problem behaviour. We conducted a meta-synthesis to explore what strategies parents use to manage irritability, non-compliance, challenging behaviour and anxiety in their children with ASD. Approaches included: (1) accommodating the child; (2) modifying the environment; (3) providing structure, routine and occupation; (4) supervision and monitoring; (5) managing non-compliance with everyday tasks; (6) responding to problem behaviour; (7) managing distress; (8) maintaining safety and (9) analysing and planning. Results suggest complex parenting demands in children with ASD and problem behaviour. Findings will inform the development of a new measure to quantify parenting strategies relevant to ASD

Geometry and field theory in multi-fractional spacetime

We construct a theory of fields living on continuous geometries with fractional Hausdorff and spectral dimensions, focussing on a flat background analogous to Minkowski spacetime. After reviewing the properties of fractional spaces with fixed dimension, presented in a companion paper, we generalize to a multi-fractional scenario inspired by multi-fractal geometry, where the dimension changes with the scale. This is related to the renormalization group properties of fractional field theories, illustrated by the example of a scalar field. Depending on the symmetries of the Lagrangian, one can define two models. In one of them, the effective dimension flows from 2 in the ultraviolet (UV) and geometry constrains the infrared limit to be four-dimensional. At the UV critical value, the model is rendered power-counting renormalizable. However, this is not the most fundamental regime. Compelling arguments of fractal geometry require an extension of the fractional action measure to complex order. In doing so, we obtain a hierarchy of scales characterizing different geometric regimes. At very small scales, discrete symmetries emerge and the notion of a continuous spacetime begins to blur, until one reaches a fundamental scale and an ultra-microscopic fractal structure. This fine hierarchy of geometries has implications for non-commutative theories and discrete quantum gravity. In the latter case, the present model can be viewed as a top-down realization of a quantum-discrete to classical-continuum transition.Comment: 1+82 pages, 1 figure, 2 tables. v2-3: discussions clarified and improved (especially section 4.5), typos corrected, references added; v4: further typos correcte

The intellectual structure and substance of the knowledge utilization field: A longitudinal author co-citation analysis, 1945 to 2004

<p>Abstract</p> <p>Background</p> <p>It has been argued that science and society are in the midst of a far-reaching renegotiation of the social contract between science and society, with society becoming a far more active partner in the creation of knowledge. On the one hand, new forms of knowledge production are emerging, and on the other, both science and society are experiencing a rapid acceleration in new forms of knowledge utilization. Concomitantly since the Second World War, the science underpinning the knowledge utilization field has had exponential growth. Few in-depth examinations of this field exist, and no comprehensive analyses have used bibliometric methods.</p> <p>Methods</p> <p>Using bibliometric analysis, specifically first author co-citation analysis, our group undertook a domain analysis of the knowledge utilization field, tracing its historical development between 1945 and 2004. Our purposes were to map the historical development of knowledge utilization as a field, and to identify the changing intellectual structure of its scientific domains. We analyzed more than 5,000 articles using citation data drawn from the Web of Science^®. Search terms were combinations of knowledge, research, evidence, guidelines, ideas, science, innovation, technology, information theory and use, utilization, and uptake.</p> <p>Results</p> <p>We provide an overview of the intellectual structure and how it changed over six decades. The field does not become large enough to represent with a co-citation map until the mid-1960s. Our findings demonstrate vigorous growth from the mid-1960s through 2004, as well as the emergence of specialized domains reflecting distinct collectives of intellectual activity and thought. Until the mid-1980s, the major domains were focused on innovation diffusion, technology transfer, and knowledge utilization. Beginning slowly in the mid-1980s and then growing rapidly, a fourth scientific domain, evidence-based medicine, emerged. The field is dominated in all decades by one individual, Everett Rogers, and by one paradigm, innovation diffusion.</p> <p>Conclusion</p> <p>We conclude that the received view that social science disciplines are in a state where no accepted set of principles or theories guide research (<it>i.e.</it>, that they are pre-paradigmatic) could not be supported for this field. Second, we document the emergence of a new domain within the knowledge utilization field, evidence-based medicine. Third, we conclude that Everett Rogers was the dominant figure in the field and, until the emergence of evidence-based medicine, his representation of the general diffusion model was the dominant paradigm in the field.</p

Risk Factors for SARS-CoV-2 Infection Among US Healthcare Personnel, May-December 2020

To determine risk factors for coronavirus disease (COVID-19) among US healthcare personnel (HCP), we conducted a case-control analysis. We collected data about activities outside the workplace and COVID-19 patient care activities from HCP with positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test results (cases) and from HCP with negative test results (controls) in healthcare facilities in 5 US states. We used conditional logistic regression to calculate adjusted matched odds ratios and 95% CIs for exposures. Among 345 cases and 622 controls, factors associated with risk were having close contact with persons with COVID-19 outside the workplace, having close contact with COVID-19 patients in the workplace, and assisting COVID-19 patients with activities of daily living. Protecting HCP from COVID-19 may require interventions that reduce their exposures outside the workplace and improve their ability to more safely assist COVID-19 patients with activities of daily living

Duality and fallibility in practices of the self: The 'inclusive subject’ in diversity training

The concept of ‘inclusion’ has been gaining ground in a field known as equality and diversity work. Scholars have begun to both theorise what this concept means as a normative goal and to critically examine how it is mobilised in organisational practice. This paper contributes to the latter conversation by asking what comes to count as ‘doing inclusion’ at the level of the individual. I examine the practices of diversity training in United Kingdom organisations, in which diversity practitioners seek to transform their trainees into people who will act inclusively toward others, asking: Who is the ‘inclusive subject’ that is being constructed – imagined, sought and legitimised – through diversity training? What are the conditions of possibility that shape the emergence of this subject? And what are the possibilities that this subject affords to marginalised groups struggling for recognition within organisations? The analysis mobilises Foucault’s notions of power/knowledge, discipline, and practices of the self to describe and discuss the performance of inclusive subjectivity in the context of diversity training in the UK. The practices described are found to be facilitated by two key forms of knowledge about how the subject is characterised: duality and fallibility. The discussion of these two forms of knowledge leads us to consider the relations of both discipline and freedom that take place in diversity training.</p