This is a comprehensive biography of Ludwig Prandtl (1875-1953), the father of modern aerodynamics. His name is associated most famously with the boundary layer concept, but also with several other topics in 20th century fluid mechanics, particularly turbulence (Prandtl's mixing length). Among his disciples are pioneers of modern fluid mechanics such as Heinrich Blasius, Theodore von Kármán and Walter Tollmien. Furthermore, Prandtl founded the Aerodynamische Versuchsanstalt (AVA) and the Kaiser-Wilhelm-Institut für Strömungsforschung in Göttingen, both of them seeds for (...) the growth of fluid mechanics in Germany. Yet Prandtl was also a representative of aeronautical research - from Imperial Germany via the Weimar Republic to the "Third Reich". Although not a party member, he assumed the role of a goodwill ambassador for Nazi Germany. This objective treatment of his career will be of interest to all scientists and historians wanting to learn more about Prandtl's influence and the early development of fluid- and aerodynamics. (shrink)

Rationality - as opposed to 'ad-hoc' - and asymptotics - to emphasize the fact that perturbative methods are at the core of the theory - are the two main concepts associated with the Rational Asymptotic Modeling (RAM) approach in fluid dynamics when the goal is to specifically provide useful models accessible to numerical simulation via high-speed computing. This approach has contributed to a fresh understanding of Newtonian fluid flow problems and has opened up new avenues for tackling real (...) fluid flow phenomena, which are known to lead to very difficult mathematical and numerical problems irrespective of turbulence. With the present scientific autobiography the author guides the reader through his somewhat non-traditional career; first discovering fluid mechanics, and then devoting more than fifty years to intense work in the field. Using both personal and general historical contexts, this account will be of benefit to anyone interested in the early and contemporary developments of an important branch of theoretical and computational fluid mechanics. (shrink)

I reconstruct Aristotle’s explanation for why and how birds are capable of natural flight. For Aristotle, air is a markedly different external resting point in comparison with water and earth, and nature has designed birds so as to take advantage of the unique way in which air affects the inequality between the pushing downward, that is, the downward force and the resistance. My discussion sheds some light on Aristotle’s anticipation of some aspects of modern fluid dynamics and aerodynamics.

Deconstruction is commonly associated with the philosophy of Derrida. But there are also non-philosophers who say they engage in deconstruction, for example architects, anthropologists and literary critics. This may lead some people to suppose that deconstruction is not concerned with specifically philosophical problems.

The question of whether fluid intelligence can be differentiated from general intelligence in older adults is addressed. Data indicate that the developmental pattern of performance on fluid tasks differs from the pattern of general intelligence. These results suggest that it is important to identify changes in fluid cognitive functions associated with frontal lobe decline, as they may be early indicators of cognitive decline. (Published Online April 5 2006).

In this chapter, we consider how a commitment to acting in a child’s interestsChild's interests can be brought to bear on three specific ethical quandaries that face those caring for children at the end of lifeEnd-of-life, and how such a commitment might seem to cohere or be in tension with other principles such as autonomyAutonomy and justiceJustice. We examine the status of ‘do not resuscitateDo Not Resuscitate ’ orders in children and argue that they cannot exist in children in the (...) same form as in adults. Since the standard of ethical permissibility is set by the interestsInterest of the child, rather than the preferencesPreferences of parentParents or doctor, there is no single person with authorityAuthority to agree an adult-style DNRDo Not Resuscitate. Looking at clinically-assisted feeding or hydrationHydration, we argue that withholding, withdrawing, commencing or continuing it each constitutes an intervention and needs to be carefully justified by considering its burdens and harmsHarm in the broadest sense reasonableReasonable. Finally, we consider ‘palliative sedationPalliative sedation’ and suggest that, while there are circumstances under which sedation is an inevitable result of adequate symptom controlSymptom control, impaired consciousness does not of itself represent a way to control symptoms and should not be deliberately induced. (shrink)

We meta-analytically investigated relations between the four-branch model of ability emotional intelligence (EI) with fluid (Gf) and crystallized intelligence (Gc; 352 effect sizes; ntotal = 15,333). We found that for each branch, the strength of relations with Gf and Gc were equivalent. Understanding emotions has the strongest relation with Gf/Gc combined (ρ =.43, k = 81, n = 11,524), relative to facilitating thought using emotion (ρ =.19, k = 51, n = 7,254), managing emotions (ρ =.20, k = 74, (...) n = 11,359), and perceiving emotion (ρ =.20, k = 79, n = 9,636); for the latter, relations were also moderated by stimulus type. We conclude with implications and recommendations for the study of ability EI. (shrink)

Ernst Mach is the only person whom Einstein included on both the list of physicists he considered his true precursors, and the list of the philosophers who had most affected him. Einstein scholars have been less generous in their estimation of Mach's contributions to Einstein's work, and even amongst the more generous of them, Mach's great achievements in physics are seldom mentioned in this context. This is odd, considering Mach was nominated for the Nobel Prize in Physics three times. In (...) this paper, I examine some of Mach's work in physics that bears conceptually on Einstein's 1905 paper on Special Relativity ("On The Electrodynamics of Moving Bodies"). Mach was the first to give the correct explanation of the Doppler Effect, and he presented it in a way that Einstein echoes in his 1905 paper: laying out two apparently contradictory principles and showing how both can be retained. It is also notable that Mach's explanation was explicit about not relying on the existence of a medium of transmission for the propagation of light waves. In his work on supersonic shock waves, Mach invokes the constancy of the velocity of sound (i.e., its independence of the motion of the sound source) , just as he had invoked the constancy of the velocity of light in his work on the Doppler Effect for Light. I examine the analogies between light and sound that were drawn upon by Einstein and Mach, as well as one analogy that Einstein could have, but did not make: Cherenkov radiation, or "singing electrons", i.e., cases in which the sound of light in the medium of transmission is exceeded, which results in an optical analogue of supersonic shock waves. (shrink)

Historians and philosophers of science have examined the relationship between language and practice for a long time. Scholars have made important contributions to the field by attending to the social, cultural and economic contexts in which scientific paradigms are created and re-created. However, this article posits that while it is true that scientific practice and the artifacts they generate are both socially and discursively constructed and therefore, inextricable from the human contexts that produce them, these artifacts are not only texts (...) to be deciphered, but material things. This essay shows that the recalcitrant material dimension of my case study, a robotic moth, shapes the results of an experiment into the laws of aerodynamics in ways incommensurate with exclusively textual and/or rhetorical critiques. (shrink)

The Madelung equations map the non-relativistic time-dependent Schrödinger equation into hydrodynamic equations of a virtual fluid. While the von Neumann entropy remains constant, we demonstrate that an increase of the Shannon entropy, associated with this Madelung fluid, is proportional to the expectation value of its velocity divergence. Hence, the Shannon entropy may grow due to an expansion of the Madelung fluid. These effects result from the interference between solutions of the Schrödinger equation. Growth of the Shannon entropy (...) due to expansion is common in diffusive processes. However, in the latter the process is irreversible while the processes in the Madelung fluid are always reversible. The relations between interference, compressibility and variation of the Shannon entropy are then examined in several simple examples. Furthermore, we demonstrate that for classical diffusive processes, the “force” accelerating diffusion has the form of the positive gradient of the quantum Bohm potential. Expressing then the diffusion coefficient in terms of the Planck constant reveals the lower bound given by the Heisenberg uncertainty principle in terms of the product between the gas mean free path and the Brownian momentum. (shrink)

Blair presumes the validity of the fluid-crystallized model throughout his article. Two comparative evaluations recently demonstrated that this presumption can be challenged. The fluid-crystallized model offers little to the understanding of the structural manifestation of general intelligence and other more specific abilities. It obscures important issues involving the distinction of pervasive learning disabilities (low general intelligence) from specific, content-related disabilities that impede the development of particular skills. (Published Online April 5 2006).

Complexity–nonlinear dynamics for my purposes in this essay–is rich with metaphysical and epistemological implications but is only recently receiving sustained philosophical analysis. I will explore some of the subtleties of causation and constraint in Rayleigh-Bénard convection as an example of a complex phenomenon, and extract some lessons for further philosophical reflection on top-down constraint and causation particularly with respect to causal foundationalism.

The evolution of the equation of mass conservation in fluid mechanics is studied. Following early hydraulic approximations, and progress by Daniel and Johann Bernoulli, its first expression as a partial differential equation was achieved by d’Alembert, and soon given definitive form by Euler. Later reworkings by Lagrange, Laplace, Poisson and others advanced the subject, but all based their derivations on the conserved mass of a moving fluid particle. Later, Duhamel and Thomson gave a simpler derivation, by considering mass (...) flow into and out of a fixed portion of space. The later propagation of these derivations in nineteenth-century British textbooks and treatises is also examined, including Maxwell’s on the kinetic theory of gases. (shrink)

Fold‐switching proteins, which remodel their secondary and tertiary structures in response to cellular stimuli, suggest a new view of protein fold space. For decades, experimental evidence has indicated that protein fold space is discrete: dissimilar folds are encoded by dissimilar amino acid sequences. Challenging this assumption, fold‐switching proteins interconnect discrete groups of dissimilar protein folds, making protein fold space fluid. Three recent observations support the concept of fluid fold space: (1) some amino acid sequences interconvert between folds with (...) distinct secondary structures, (2) some naturally occurring sequences have switched folds by stepwise mutation, and (3) fold switching is evolutionarily selected and likely confers advantage. These observations indicate that minor amino acid sequence modifications can transform protein structure and function. Consequently, proteomic structural and functional diversity may be expanded by alternative splicing, small nucleotide polymorphisms, post‐translational modifications, and modified translation rates. (shrink)

Blair describes fluid cognition as highly related to working memory and executive processes, and dependent on the integrity of frontal-lobe functioning. However, the literature review appears to neglect potential contributions to fluid cognition of the focus of attention as an important information-storage device, and the role of posterior brain regions in that kind of storage. Relevant cognitive and imaging studies are discussed. (Published Online April 5 2006).

It may be seen, then, that if one was prepared to accept the existence of insulating sheaths on the nerves, all the arguments raised against the proposed identification of the nervous and electrical fluids, except one, could be answered satisfactorily. The single exception involved the question of how an electrical disturbance in the brain could be confined to a single nerve, and, as was indicated earlier, it was scarcely fair to hold this sort of objection against the electrical theory alone. (...) In that case, there remained no convincing argument to show why one should not accept the identification of the two fluids. On the other hand, of course, it remained an open question as to whether there was any convincing argument to show why one should accept the identification either. Galvani thought that his experiments provided just such an argument. (shrink)

The experience of the twentieth century bears witness to the abuse, mutilation and homicide of the vulnerable made possible by the power of the state, mass markets, and medical and financial interests. Suggestions for reform of the law regarding food and fluids typically take place in the context of utilitarian personistic “quality-of-life” presuppositions, and interests in shifting legal responsibility for life-and-death decisions, medical research, drug trials, organ harvesting as well as more mundane bureaucratic concerns like bed-clearing. With the Western world (...) undergoing massive demographic change and a growing ageing and non-productive population, it cannot be assumed that these alterations to the positive law are problem-free. By allowing new agents power to require that food and fluids be withdrawn, non-therapeutic research and other procedures (like abortion and sterilisation) be performed on non-consenting patients, novel legislation such as that discussed cannot be regarded as autonomy enhancing so much as a threat to human rights. These laws although touted as progressive, more often than not invite routine abuse and destruction of the vulnerable, obscure accountability and create an inconsistent body of law, with conflicting obligations for health professionals. (shrink)

Blair's assertion that fluid intelligence (gF) is distinct from general intelligence (g) is contradictory to cumulative evidence from intelligence research, including extant and novel evidence about generational IQ gains (Lynn–Flynn effect). Because of the near unity of gF and g, his hypothetical concept of gF' (gF “purged” of g variance) may well be a phlogiston theory. (Published Online April 5 2006).

This article contributes to the contemporary debate on land and water grabbing through a detailed, qualitative case study of horticultural agribusinesses which have settled in Tanzania, disrupting patterns of land and water use. In this paper we analyse how capitalist settler farms and their upstream and downstream peasant neighbours along the Nduruma river, Tanzania, expand and defend their water use. The paper is based on 3 months of qualitative field work in Tanzania. We use the echelons of rights analysis framework (...) combined with the concept of institutional bricolage to show how this contestation takes place over the full spectrum of actual abstractions, governance and discourses. We emphasise the role different national development narratives play in shaping day-to-day contestations over water shares and rule-making. Ultimately, we emphasise that water grabbing is not a one-time event, but rather an on-going struggle over different water resources. In addition, we show how a perceived beneficial development of agribusinesses switching to groundwater allows them to avoid peasant-controlled institutions, avoiding further negotiation between the different actors and improving their image among neighbouring communities. This development illustrates how complex and obscured processes of water re-allocation can be without becoming illegal per se. (shrink)

We plead for a fluid margin, or mixed/indeterminate buffer zone, between Physical and Non-Physical Causal Closures, and for a Neutrosophic Causal Closure Principle claiming that the chances of all physical effects are determined by their prior partially physical and partially non-physical causes.

We generalize the nonlinear one-dimensional equation of a fluid layer for any depth and length as an infinite-order differential equation for the steady waves. This equation can be written as a q-differential one, with its general solution written as a power series expansion with coefficients satisfying a nonlinear recurrence relation. In the limit of long and shallow water (shallow channels) we reobtain the well-known KdV equation together with its single-soliton solution.

This article contributes to the contemporary debate on land and water grabbing through a detailed, qualitative case study of horticultural agribusinesses which have settled in Tanzania, disrupting patterns of land and water use. In this paper we analyse how capitalist settler farms and their upstream and downstream peasant neighbours along the Nduruma river, Tanzania, expand and defend their water use. The paper is based on 3 months of qualitative field work in Tanzania. We use the echelons of rights analysis framework (...) combined with the concept of institutional bricolage to show how this contestation takes place over the full spectrum of actual abstractions, governance and discourses. We emphasise the role different (inter)national development narratives play in shaping day-to-day contestations over water shares and rule-making. Ultimately, we emphasise that water grabbing is not a one-time event, but rather an on-going struggle over different water resources. In addition, we show how a perceived beneficial development of agribusinesses switching to groundwater allows them to avoid peasant-controlled institutions, avoiding further negotiation between the different actors and improving their image among neighbouring communities. This development illustrates how complex and obscured processes of water re-allocation can be without becoming illegal per se. (shrink)

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)

The human body has been a potent and persistent metaphor for social and political relations throughout human history. For example, different parts of the body have traditionally represented different social functions. We refer to the ‘head of state’ without really recognizing the metaphor, and the heart has been a rich source of ideas about life, imagination and emotions. The heart is the house of the soul and the book of life, and the ‘tables of the heart’ provided an insight into (...) the whole of Nature. The hand also plays an important role in conventional imagination regarding things that are beautiful (handsome) or damaged and incomplete (handicap). We can generalize from these diverse examples to argue that the fluids flowing from the inside of the body to the outside are regarded as socially dangerous and contaminating, because these fluids on the outside of the body directly challenge our sense of order and orderliness. This inside/outside division of the body combines with a wet/dry dichotomy to delineate these risky borders. Although leaking bodies have been a source of ancient metaphors of disorder, the modern world, that sociologists increasingly characterize by its liquidity, is peculiarly fascinated by flow as an image of global flexibility. The more our world is economically and militarily interconnected, the more we fear social fluidity. In political terms, asylum seekers and terrorists are thought not to respect our bodies or our borders; we are especially sensitive to their capacity to disrupt the solidity of sovereignty. In short, metaphors of the human body, even in an age of high technology, continue to shape the social and political imagination, but they are challenged by emerging metaphors of liquidity, that is by liquid modernity. (shrink)

Blair proposes that fluid intelligence, working memory, and executive function form a unitary construct: fluid cognition. Recently, our group has utilized a combined correlational–experimental cognitive neuroscience approach, which we argue is beneficial for investigating relationships among these individual differences in terms of neural mechanisms underlying them. Our data do not completely support Blair's strong position. (Published Online April 5 2006).

An examination of oracles in popular forms of Cuban espiritismo invites a rethinking of the role of “randomness” and “context” in the anthropology of divination. Through an analysis of the ways by which spirit mediums develop as persons, and their implications for the mechanics of divination, I argue that among espiritistas the meaning of particular configurations cannot be separated from the event that brings them about. Relatively simple in their properties (e.g. water), spiritist oracles function to provide impulse to a (...) perceived metaphysical universe that requires the generation of movement in order to achieve instantiation. The argument is that this movement provides a background of chaos essential to the purpose of divination. To demonstrate this, I forward an analogy to the language of electronic voice phenomena in parapsychology, in particular with its concept of “noise.” In both EVP and espiritismo, “noise” is the substance that allows spirits to communicate. (shrink)

Several paradoxes of infinity have recently featured in this journal involving gases distributed in a denumerable infinite series of compartments. I shall demonstrate in this paper that:a) None of these new paradoxes applies where the gases comply with both Boyle’s law and Avogadro’s law. As several of these new paradoxes expressly require compliance with Boyle’s law, it is unclear, in principle, as to whether there is a plausible model of gas that is able to uphold them all.b) Notwithstanding a), any (...) of the above paradoxes can be reinstated by acknowledging that there are two distinct, non-equivalent concepts of ideal gas. Indeed, the various infinity puzzles actually enable a distinction to be made between the two concepts. (shrink)

Working memory has been shown to be strongly related to fluid intelligence; however, our goal is to shed further light on the process of information compression in working memory as a determining factor of fluid intelligence. Our main hypothesis was that compression in working memory is an excellent indicator for studying the relationship between working-memory capacity and fluid intelligence because both depend on the optimization of storage capacity. Compressibility of memoranda was estimated using an algorithmic complexity metric. (...) The results showed that compressibility can be used to predict working-memory performance and that fluid intelligence is well predicted by the ability to compress information. We conclude that the ability to compress information in working memory is the reason why both manipulation and retention of information are linked to intelligence. This result offers a new concept of intelligence based on the idea that compression and intelligence are equivalent problems. (shrink)

Although working memory capacity and executive function contribute to human intelligence, we question whether there is an equivalence between them and fluid intelligence. We contend that any satisfactory neurobiological explanation of fluid intelligence needs to include abstraction as an important computational component of brain processing. (Published Online April 5 2006).

In several of his writings from the 1680s, Leibniz presents an argument for the claim that there are no determinate or precise shapes in things, and states that shape contains something imaginary a...

Blair equates the constructs of working memory (WM), executive function, and general fluid intelligence (gF). We argue that there is good reason not to equate these constructs. We view WM and gF as separable but highly related, and suggest that the mechanism behind the relationship is controlled attention – an ability that is dependent on normal functioning of the prefrontal cortex. (Published Online April 5 2006).

Seasonal and historical transformations of ice and permafrost suggest that the Mackenzie Delta in Arctic Canada can be understood as a solid fluid. The concerns and practices of delta inhabitants show that fluidity and solidity remain important attributes in a solid fluid delta. They are significant not as exclusive properties, but as relational qualities, in the context of particular human projects and activities. Indigenous philosophies of ‘the land’ and Henri Lefebvre’s notion of ‘tempo’ in Rhythmanalysis: Space, Time and (...) Everyday Life (2004) may help to illustrate the predicament of living in a world that is solid and fluid rhythmically, and in relation to particular practices. Economic, political, sociocultural and physical transformations can all be experienced as both solid and fluid, depending on the degree to which they resonate with people’s purposes. In a world where everything seems to be changed and changing, solidity and fluidity may best be seen as indications of relative differences in tempo. (shrink)