Pantographs are important devices on high-speed trains. When a train runs at a high speed, concave and convex parts of the train cause serious airflow disturbances and result in flow separation, eddy shedding, and breakdown. A strong fluctuation pressure field will be caused and transformed into aerodynamic noises. When high-speed trains reach 300 km/h, aerodynamic noises become the main noise source. Aerodynamic noises of pantographs occupy a large proportion in far-field aerodynamic noises of the whole train. Therefore, the problem (...) of aerodynamic noises for pantographs is outstanding among many aerodynamics problems. This paper applies Detached Eddy Simulation to conducting numerical simulations of flow fields around pantographs of high-speed trains which run in the open air. Time-domain characteristics, frequency-domain characteristics, and unsteady flow fields of aerodynamic noises for pantographs are obtained. The acoustic boundary element method is used to study noise radiation characteristics of pantographs. Results indicate that eddies with different rotation directions and different scales are in regions such as pantograph heads, hinge joints, bottom frames, and insulators, while larger eddies are on pantograph heads and bottom frames. These eddies affect fluctuation pressures of pantographs to form aerodynamic noise sources. Slide plates, pantograph heads, balance rods, insulators, bottom frames, and push rods are the main aerodynamic noise source of pantographs. Radiated energies of pantographs are mainly in mid-frequency and high-frequency bands. In high-frequency bands, the far-field aerodynamic noise of pantographs is mainly contributed by the pantograph head. Single-frequency noises are in the far-field aerodynamic noise of pantographs, where main frequencies are 293 Hz, 586 Hz, 880 Hz, and 1173 Hz. The farther the observed point is from the noise source, the faster the sound pressure attenuation will be. When the distance of two adjacent observed points is increased by double, the attenuation amplitude of sound pressure levels for pantographs is around 6.6 dB. (shrink)

A physically consistent semi-classical treatment of black holes requires universality arguments to deal with the `trans-Planckian' problem where quantum spacetime effects appear to be amplified such that they undermine the entire semi-classical modelling framework. We evaluate three families of such arguments in comparison with Wilsonian renormalization group universality arguments found in the context of condensed matter physics. Our analysis is framed by the crucial distinction between robustness and universality. Particular emphasis is placed on the quality whereby the various arguments are (...) underpinned by `integrated' notions of robustness and universality. Whereas the principal strength of Wilsonian universality arguments can be understood in terms of the presence of such integration, the principal weakness of all three universality arguments for Hawking radiation is its absence. (shrink)

We discuss the status of gravitational radiation in Newtonian theories. In order to do so, we consider various options for interpreting the Poisson equation as encoding propagating solutions, reflect on the extent to which limit considerations from general relativity can shed light on the Poisson equation’s conceptual status, and discuss various senses in which the Poisson equation counts as a dynamical equation.

A point charge accelerating under the influence of an external force emits electromagnetic radiation that reduces the increase in its mechanical energy. This causes a reduction in the particle's acceleration. We derive the decrease in acceleration due to radiation reaction for a particle accelerating parallel to its velocity, and show that it has a negligible effect.

In the framework of classical electromagnetism, a charge however accelerated with respect to an inertial frame radiates energy, in any circumstance. Regarding the energy as made of photons, the hypothesis is here introduced that the emission of a photon is only possible as a result of a change of the energy of the charge, which requires an energy-work exchange with the accelerating field. On such an hypothesis an elementary impulsive-dissipative model for the photon emission is constructed, in the framework of (...) special relativity, in which no energy radiation is emitted from a charge in a central Coulomb field uniformly describing a circular orbit. (shrink)

A physically consistent semi-classical treatment of black holes requires universality arguments to deal with the ‘trans-Planckian’ problem where quantum spacetime effects appear to be amplified such that they undermine the entire semi-classical modelling framework. We evaluate three families of such arguments in comparison with Wilsonian renormalization group universality arguments found in the context of condensed matter physics. Our analysis is framed by the crucial distinction between robustness and universality. Particular emphasis is placed on the quality whereby the various arguments are (...) underpinned by ‘integrated’ notions of robustness and universality. Whereas the principal strength of Wilsonian universality arguments can be understood in terms of the presence of such integration, the principal weakness of all three universality arguments for Hawking radiation is its absence. (shrink)

Inconsistencies in the usual interpretation of the absorber theory of radiation are exposed which invalidate an experiment proposed recently by Heron and Pegg. An earlier experiment by Partridge necessarily gave a null result owing to absorption on the far side of the Earth of any advanced radiation which may have been present.

No artigo "Einstein y el efecto Compton", publicado neste número de SCIENTIÆ UDIA: , os autores estranham o fato de Einstein não ter declarado mais claramente o quanto esse efeito comprovava definitivamente o carácter corpuscular da radiação. A presente nota crítica pretende fornecer elementos adicionais de apreciação que permitam acompanhar o método de exploração do domínio dos quanta elaborado por Einstein, na ausência de uma teoria adequada, e praticado por ele de 1905 à 1925, evidenciando por esse meio propriedades inéditas (...) e inusuais dos fenômenos quânticos; e também explicitar o alvo que ele queria almejar com sua investigação e entender melhor seu pensamento acerca dos quanta. Três argumentos principais são delineados. (1) O problema dos quanta de luz está estreitamente ligado com aquele das propriedades quânticas da matéria atômica em geral, do qual não pode ser separado. (2) Outro experimento, realizado pouco depois do experimento de Compton, trouxe um elemento adicional, necessário para que se possa atribuir sem nenhuma reticiência uma quantidade de movimento à radiação, isto é, o caráter individual da interação da qual a radiação toma parte. (3) Enfim, os trabalhos de Einstein sobre a estatística quântica, realizados no mesmo período, apontavam na direção da generalização do duplo caráter onda-corpúsculo à radiação, como também à matéria, evidenciando a indiscernibilidade dos estados idênticos e revelando, assim, propriedades fundamentais radicalmente novas que toda teoria quântica futura haveria de incluir. In the article "Einstein y el efecto Compton", published in this issue of SCIENTIÆ UDIA: , the authors wonder why Einstein did not claim unambiguously that this phenomenon was a clear and definitive proof of the corpuscular character of radiation. The aims of the present critical note are to provide additional comments that serve to clarify the method that Einstein used for exploring the quantum domain, in the absence of a satisfactory theory - a method he practiced from 1905 to 1925, and from which he obtained evidence of new and unusual properties of quantum phenomena; and to try to formulate what he wanted to get at in his investigations, so as to understand better his thinking about quanta. Three main arguments are sketched. (1) The problem of light quanta cannot be separated from that of the quantum properties of atomic matter in general. (2) Another experiment, performed shortly after Compton's yielded a further element that was necessary to obtain a definitive answer to the question of whether a quantity of motion can be attributed to radiation. (3) Finally, Einstein's works on quantum statistics during that period pointed towards a generalization of the double wave-corpuscle behavior of radiation, and also of matter, providing evidence for the indistinguishability of identical states, thus revealing radically new fundamental properties that should be accounted for by any further quantum theory. (shrink)

It is shown that a newly derived “exact expression” for radiation of an accelerated charge in the recent literature is simply incorrect, having arisen because of a wrong relativistic transformation of the distance parameter. The ensuing claim that the newly derived expression alone satisfies the energy conservation for the electromagnetic radiation, is based on a wrong reasoning where a proper distinction between the time during which the radiation is received and the time for emission (retarded time of (...) the charge) was not maintained. (shrink)

Newton’s impact on Enlightenment natural philosophy has been studied at great length, in its experimental, methodological and ideological ramifications. One aspect that has received fairly little attention is the role Newtonian “analogies” played in the formulation of new conceptual schemes in physiology, medicine, and life science as a whole. So-called ‘medical Newtonians’ like Pitcairne and Keill have been studied; but they were engaged in a more literal project of directly transposing, or seeking to transpose, Newtonian laws into quantitative models of (...) the body. I am interested here in something different: neither the metaphysical reading of Newton, nor direct empirical transpositions, but rather, a more heuristic, empiricist construction of Newtonian analogies. Figures such as Haller, Barthez, and Blumenbach constructed analogies between the method of celestial mechanics and the method of physiology. In celestial mechanics, they held, an unknown entity such as gravity is posited and used to mathematically link sets of determinate physical phenomena (e.g., the phases of the moon and tides). This process allows one to remain agnostic about the ontological status of the unknown entity, as long as the two linked sets of phenomena are represented adequately. Haller et. al. held that the Newtonian physician and physiologist can similarly posit an unknown called ‘life’ and use it to link various other phenomena, from digestion to sensation and the functioning of the glands. These phenomena consequently appear as interconnected, goal-oriented processes which do not exist either in an inanimate mechanism or in a corpse. In keeping with the empiricist roots of the analogy, however, no ontological claims are made about the nature of this vital principle, and no attempts are made to directly causally connect such a principle and observable phenomena. The role of the “Newtonian analogy” thus brings together diverse schools of thought, and cuts across a surprising variety of programs, models and practices in natural philosophy. (shrink)

We examine the problem of deducing the geodesic motion of test particles from Einstein's vacuum field equations and its extension to include gravitational radiation reaction. In the latter case we obtain an equation of motion for a particle which incorporates radiation reaction of the electrodynamical type, but due to shearing radiation, together with a mass-loss formula of the Bondi-Sachs type.

ArgumentThe paper focuses on the instrumentality of writing in the context of scientific research. It is suggested that the tool-character of writing is related to specific writing procedures, such as the list. These procedures can vary in their degree of complexity and often follow rules that are not codified. In any case, writing procedures can be characterized as non-material devices of “concretion.” Two examples from the notebooks of the physicist and philosopher of science, Ernst Mach (1838–1916), will help to (...) develop the notion of writing procedures. Typical for Mach's use of his notebooks, they highlight the effects of writing in the context of reasoning and reflecting. (shrink)

Computer technology and related Internet of things technology have penetrated into people’s daily life and industrial production; even in competitive sports training and competition, the Internet of things technology has also been a large number of applications. Traditional intelligent wearable devices are mainly used to calculate the steps of athletes or sports enthusiasts, corresponding physical data, and corresponding body indicators. The energy consumption calculated by these indexes is rough and the corresponding error is large. Based on this, this paper (...) will design a wearable device which can accurately calculate and monitor sports energy consumption based on relevant sensors and Internet of things technology. The corresponding core algorithm is the step counting algorithm, which can accurately calculate the relationship between human motion and the corresponding energy consumption and feed back to the intelligent device. In the experiment, the wearable device designed in this paper is compared with the traditional intelligent device. The experiment shows that the wearable device proposed in this paper is more accurate in energy consumption estimation than the traditional device, and its corresponding energy consumption is relatively small. (shrink)

This book is published in conjunction with an exhibition at the Getty Museum from November 13, 2001, through February 6, 2002.

This article documents some foregrounding devices that the media use to attract readers' attention to linguistic forms, all identified in sports reports relating to the Euro 2004 Football Championship published in various British newspapers. A functional explanation is offered in terms of the poetic and interactive character of such devices and their role in simulating friendship and encouraging `bonding' between the writers and readers. Their omnipresence in the British media is linked with structural characteristics of the English language, (...) the readiness of the British to tolerate manipulation of linguistic forms, and the general trend towards `infotainment' in the media. (shrink)

In this paper, I argue against an influential view of Frege's writings on indexical and other context-sensitive expressions, and in favour of an alternative. The centrepiece of the influential view, due to (among others) Evans and McDowell, is that according to Frege, context-sensitiveword-meaning plus context combine to express senses which are essentially first person, essentially present tense and so on, depending on the context-sensitive expression in question. Frege's treatment of indexicals thus fits smoothly with his Intuitive Criterion of difference of (...) sense. On my view, by contrast, Frege stuck by the view which he held in his unpublished 1897 ‘Logic’, namely that the senses expressed by the combination of context-sensitive word-meaning and context could just as well be expressed by means of non-context-sensitive expressions: being first person, present tense and so on are properties, in Frege's view, only of language, not of thought. Given the irreducibility of indexicals – a phenomenon noticed by Castañeda, Perry and others – Frege's treatment of indexicals thus turns out to be inconsistent with the Intuitive Criterion. I argue that Frege was not aware of the inconsistency because he was not aware of the irreducibility of indexicals. This oversight was possible because the source of Frege's interest in indexicals, as inother context-sensitive expressions, differed from that of contemporary theorists. Whereas contemporary theorists are most often interested in indexicals (and in Frege's treatment of them) because they are interested in the indexical versions of Frege's Puzzle and their relation to psychological explanation, Frege himself was interested in them because they pose a prima facie threat to his general conception of thoughts. The only indexical expression Frege's view of which the above account does not cover is ‘I’ insofar as it is associated with ‘special and primitive’ senses, but Frege did not introduce such senses with a view to explaining theirreducibility of ‘I’ his real reason for introducing them remains obscure. (shrink)

The use of charged-particle radiation therapy is an increasingly important development in the treatment of cancer. One of the most pressing controversies about the use of this technology is whether randomised controlled trials are required before this form of treatment can be considered to be the treatment of choice for a wide range of indications. Equipoise is the key ethical concept in determining which research studies are justified. However, there is a good deal of disagreement about how this concept (...) is best understood and applied in the specific case of CPRT. This report is a position statement on these controversies that arises out of a workshop held at Wolfson College, Oxford in August 2011. The workshop brought together international leaders in the relevant fields , including proponents on both sides of the debate, in order to make significant progress on the ethical issues associated with CPRT research. This position statement provides an ethical platform for future research and should enable further work to be done in developing international coordinated programmes of research. (shrink)

Internet-enabled mobile devices expand the virtual spaces of Internet users. Mobile Internet users encounter continuous connectivity where they are not only always on but also always with the device. Users are presented with situations of continuous connected presence requiring them to deal with the overwhelming volume of virtual interaction. This study reports from a longitudinal study of 35 university students in Australia conducted in 2011/2012. Mobile tablet devices were given to participants who had never owned one before, to (...) be observed over a period of 1 year. By qualitatively exploring how users experience and negotiate with the added virtual space, this study found that while users benefit from continuous connectivity, they also adopt strategies to disconnect from the ubiquitous access especially when engaging in tasks that require undivided attention. New users go through adjustment by developing their own involvement shield strategies while experimenting with online colocation and copresence. (shrink)

Ethno-pragmatics as device to understand the culturally Other is essential when we believe that there is a nexus of intimate relationships between languageand culture. The whole idea of ethno-pragmatics is to understand local life-worlds in the wake of celebrating particularism in inter-cultural communication. Ethnopragmatics basically appreciates language practices in terms that make sense to the people concerned, whether in terms of indigenous values, beliefs, attitudes, social categories or emotions, and so on. Understanding cultural keywords is pertinent in ethno-pragmatics. These living (...) words provide the best key to a culture’s values and assumptions, and they are embedded in the cultural scripts of the society/community. With the above positioning, we suggested that ethno-pragmatics be the device for intercultural communication intelligence (ICQ). In this work we employed a cultural script quest in order to capture/understand the tapestry of Malay culture. Bahasa (“language”) is one of the main Malay cultural keywords. The Malays relate bahasa to various norms and beliefs that encompass their life-world. Bahasa is molecularly related to their emotions, sense-making and aesthetics. As an illustration, we provide ICQ-at-work with halus as a technique of utilizing bahasa for successful speech-acts. Specifically, we narrate on Malay “indirectness” as a way of having conversation with the culturally Other. (shrink)

Narratives surrounding ionizing radiation have often minimized radioactivity’s impact on the health of human and non-human animals and the natural environment. Many Cold War research policies, practices, and interpretations drove nuclear technology forward by institutionally obscuring empirical evidence of radiation’s disproportionate and low-dose harm—a legacy we still confront. Women, children, and pregnancy development are particularly sensitive to exposure from radioactivity, suffering more damage per dose than adult males, even down to small doses, making low doses a cornerstone of (...) concern. Evidence of compounding generational damage could indicate increased sensitivity through heritable impact. This essay examines the existing empirical evidence demonstrating these sensitivities, and how research institutions and regulatory authorities have devalued them, willingly sacrificing health in the service of maintaining and expanding nuclear technology. Radiation’s disproportionate impacts should now be the research and policy focus, as society is poised to make crucial and long-lasting decisions regarding climate change mitigation and future energy sources. (shrink)

In many physical systems, coupling forces provide a way of carrying the energy stored in adjacent harmonic oscillators from place to place, in the form of waves. The wave equations governing such phenomena are time-symmetric: they permit the opposite processes, in which energy arrives at a point in the form of incoming concentric waves, to be lost to some external system. But these processes seem rare in nature. What explains this temporal asymmetry, and how is it related to the thermodynamic (...) asymmetry? This paper attempts to clarify these old issues, in the light of recent contributions. After brief introductory remarks (§1), the paper is in three main parts. §2 examines the so-called ‘Sommerfeld Radiation Condition’, arguing that its link to the observed asymmetry is much less direct than commonly supposed. §3 begins with Zeh's proposal to make the Sommerfeld condition an ingredient in an explanation of the observed asymmetry, and makes explicit a useful distinction between two ways in which the thermodynamic asymmetry might connect to the radiation asymmetry. §4 reviews a proposal I have defended in earlier work about the relation of the radiative asymmetry to that of thermodynamics, and defends it against recent objections by Zeh and Frisch. I also distinguish it from a recent proposal due to North. I agree with North that the observed asymmetry of radiation stems from the low entropy history, but argue that she mis-characterises the asymmetry, and hence misses a crucial element in a proper account of the role of the low entropy past. (shrink)

The modern understanding of radiation got its start in 1895 with X-rays discovered by Wilhelm Röntgen, followed in 1896 by Henri Becquerel’s discovery of radioactivity. The development of the study of radiation opened a vast field of research concerning various disciplines: chemistry, physics, biology, geology, sociology, ethics, etc. Additionally, new branches of knowledge were created, such as atomic and nuclear physics that enabled an in-depth knowledge of the matter. Moreover, during the historical evolution of this body of knowledge (...) a wide variety of new technologies was emerging. This article seeks to analyze the characteristics of experimental research in radioactivity and microphysics, in particular the relationship experience-theory. It will also be emphasized that for more than two decades, since the discovery of radioactivity, experiments took place without the theory being able to follow experimental dynamics. Some aspects identified as structural features of scientific research in the area of radiation and matter will be addressed through historical examples. The inventiveness of experiments in parallel with the emergence of quantum mechanics, the formation of teams and their relationship with technology developed from the experiments, as well as the evolution of microphysics in the sense of “Big Science” will be the main structural characteristics here focused. The case study of research in radioactivity in Portugal that assumes a certain importance and has structural characteristics similar to those of Europe will be presented. (shrink)

Although lie detection procedures have been fundamentally criticized since their inception at the beginning of the 20th century, they are still in use around the world. In addition, they have created some remarkable appeal in the context of counterterrorism policies. Thereby, the links between science and fiction in this topic are quite tight and by no means arbitrary: In the progressive narrative of the lie detection devices, there is a promise of changing society for the better, which is entangled (...) in a fictional narrative provided by many cinematic and literary examples. By drawing on the concept of “diegetic technologies” formulated by David Kirby, we want to highlight the role of science fictional narratives in the historical development and current application of lie detection procedures. We therefore aim to use this conceptual frame to analyze the role of prevention-oriented mind reading procedures, which are developed for or already used in the “war on terror” with reference to their fictional predecessors. One virulent factor has to be highlighted in this context: The fictional engagement with possible new lie detection practices is in itself creating a legitimating ground for future security technologies. (shrink)

Like the National Commission and the President's Commission, the Advisory Committee on Human Radiation Experiments was formed to carry out specific ethical tasks. Yet the committee also had an “openness” mission, a charge to investigate allegations that the U.S. government secretly exposed Americans to environmental releases of radiation. Eighteen months later—and after sixteen public meetings, more than 200 interviews, and the review of about 400,000 documents—the committee delivered a 925‐page report to the president.

During the fall of 2001 (October 22–25), The Norwegian Radiation Protection Authority (NRPA) and the Agricultural University of Norway arranged a consensus conference on the protection of the environment against ionising radiation. The motive for the conference was the need to study the ethical and philosophical basis for protection of nature in its own right. The conference was funded by Nordic Nuclear Safety Research (NKS), in cooperation with the International Union of Radioecology (IUR). The National Committee for Research (...) Ethics in Science and Technology (NENT) was hired as facilitators for the consensus process. This paper will give a brief outline of the aims and method of the conference, distinguishing these from other kinds of consensus conferences. The paper ends with some general reflections on the appropriateness of seeking consensus on ethics-related issues among experts. (shrink)

The focus of this paper are the ethical, legal and social challenges for ensuring the responsible use of “big brain data”—the recording, collection and analysis of individuals’ brain data on a large scale with clinical and consumer-directed neurotechnological devices. First, I highlight the benefits of big data and machine learning analytics in neuroscience for basic and translational research. Then, I describe some of the technological, social and psychological barriers for securing brain data from unwarranted access. In this context, I (...) then examine ways in which safeguards at the hardware and software level, as well as increasing “data literacy” in society, may enhance the security of neurotechnological devices and protect the privacy of personal brain data. Regarding ethical and legal ramifications of big brain data, I first discuss effects on the autonomy, the sense of agency and authenticity, as well as the self that may result from the interaction between users and intelligent, particularly closed-loop, neurotechnological devices. I then discuss the impact of the “datafication” in basic and clinical neuroscience research on the just distribution of resources and access to these transformative technologies. In the legal realm, I examine possible legal consequences that arises from the increasing abilities to decode brain states and their corresponding subjective phenomenological experiences on the hitherto inaccessible privacy of these information. Finally, I discuss the implications of big brain data for national and international regulatory policies and models of good data governance. (shrink)

In the last decades, new technologies have improved the survival of patients affected by chronic illnesses. Among them, left ventricular assist device has represented a viable solution for patients with advanced heart failure. Even though the LVAD prolongs life expectancy, patients’ vulnerability generally increases during follow up and patients’ request for the device withdrawal might occur. Such a request raises some ethical concerns in that it directly hastens the patient’s death. Hence, in order to assess the ethical acceptability of LVAD (...) withdrawal, we analyse and examine an ethical argument, widely adopted in the literature, that we call the “descriptive approach”, which consists in giving a definition of life-sustaining treatment to evaluate the ethical acceptability of treatment withdrawal. Focusing attention on LVAD, we show criticisms of this perspective. Finally, we assess every patient’s request of LVAD withdrawal through a prescriptive approach, which finds its roots in the criterion of proportionality. (shrink)