Tuesday, April 24, 2012

Radials and cross-plies in racing

"The higher mileage and better handling of a radial tyre does not come from a lower running temperature...Tyres are discarded when the treads are worn. If temperature were the culprit they would fail due to reversion of the carcass rubber [reversion is the process by which vulcanized rubber reverts back to its pre-vulcanized state] and/or loss of adhesion between textile [carcass] and rubber due to thermal degradation of the interface polymer. A radial tyre wears better because the tread is braced onto the road and does not squirm or distort as it does in a cross ply, whose tread is deflected by the movement of undertread plies as they move in concert with the total tyre reinforcement. Distortion in a radial tyre is almost wholly accommodated in the side walls. As a consequence of this, the tyre runs cooler.

"The road holding of a radial is superior, but once breakaway point is reached you lose adhesion very rapidly. Where controlled adhesion loss is required, as in a racing car tyre, then a cross ply tyre is used. This problem can be mitigated in a radial by fitting an asymetric tread, with progressive breakaway characteristics." (Nicholas M Doak, Rubber Journal. New Scientist 29 Jun 1972, p772).

Truly, the origins of the modern world can be found in the 1970s. However, Nicholas Doak's letter to New Scientist poses several important questions:

(1) If radial tyres suffer from a sudden loss of adhesion, then does the universal adoption of radial tyres in Formula 1 since 1983 explain why the cars are so rarely held in a controlled slide (Sebastien Vettel, Variante Ascari, Monza 2011 notwithstanding).

(2) How was Gilles Villeneuve able to hold his Michelin-shod Ferrari in so many controlled slides?

(3) Now that Formula 1 has a control tyre formula, why don't we introduce an asymmetric tread, or something similar, to make it easier for the drivers to slide the cars?

Saturday, April 14, 2012

Wind-tunnel nozzles and televisions

The power consumption of a wind-tunnel cubes with the velocity, hence an efficient tunnel design keeps the velocity as low as possible in all sections other than the working section. A nozzle is used to increase the velocity in the working section, and then a diffuser (or two) is used to reduce the velocity after the working section.

A typical wind-tunnel nozzle consists of two profiles, the first of which is concave, the second convex. It is important to avoid boundary layer separation in both parts of the nozzle, but in the case of a turbulent boundary layer, convex curvature reduces turbulent kinetic energy and skin friction, whilst concave curvature has the opposite effect (relative to a flat plate). The boundary layer over the concave surface is thicker than that over a flat plate, whilst the boundary layer over a convex surface is thinner, and therefore less prone to separation. The concave section is therefore more elongated than the convex section.

Note that the coke-bottle section on a Formula 1 car also features a convex-concave transition, although in this case the airflow is external and the convex section comes first as the sidepods taper inwards.

Meanwhile, for a wind-tunnel with a rectangular cross-section, the nozzle design is a curious echo of the external case of a late 1990s Cathode-Ray-Tube television.

An approximate macroscopic geometrical isomorphism, which was only implicate in the laws of physics, until the world of engineering made it explicate.

Tuesday, April 10, 2012

The Brain is Wider than the Sky: A Review

As the Stanford Encyclopedia of Philosophy puts it, "the concept of the aesthetic descends from the concept of taste."

This book is a sustained complaint against what writer and journalist Bryan Appleyard terms the "simplifying forces of the new machine age and reductive accounts of the human mind," (p228). These things, we discover, are not to Bryan's taste.

Whilst Appleyard's attack on the utopianism of cyber-technocracy is well justified, he also dislikes what he refers to as the materialism and reductionism of much of modern science. This criticism, however, stems from an inadequate understanding of the scientific method.

"Modern science," writes Appleyard in the first chapter, "is the exploration of the physical world through observation, experimentation and, latterly, through computer modelling," (p3). Tellingly, Bryan neglects to mention here one of the crucial components of modern science: theory.

The defining characteristic of modern science is that it unifies the empirical with the theoretical. If Appleyard has failed to absorb this fact, then he has grasped nothing of the modern scientific method. It is a failure of understanding which he repeats later in the book when the discussion turns to financial modelling: "Computer modelling is the first new way of doing science since Galileo. It adds a third method to experiment and observation," (p183).

Throughout the book, Appleyard puts great importance on the notion of complexity, and places it in opposition to reductionistic science:

"If a system like a human body produces something more than its parts, where does that 'more' come from and what is it? The question is fundamental and threatening to reductionism and simple-minded materialism.

"In complex systems 'more' is defined as 'emergent properties'. There are things the system can do which are not predictable from the constituents of the system, because they do not arise simply as a sum of all the properties of the parts of the system,"

Appleyard's simplistic understanding of reductionism is inadequate here because it fails to acknowledge three crucial concepts: (i) the scientific understanding of microscopic interactions; (ii) the recovery of macroscopic systems by coarse-graining over microscopic systems; and (iii) the distinction between epistemological and ontological reductionism.

Firstly, scientists explain the properties of macroscopic, composite systems not only in terms of the properties of their parts, but also in terms of the way in which those parts are organised and interact. The 'more' which makes a composite entity more than its parts, are the relationships between the parts. Scientists understand this very well: it is, for example, why diamond has different characteristics than graphite; both substances consist merely of carbon atoms, but what gives diamond its hardness is the manner in which those carbon atoms are organised.

Secondly, scientists understand that the higher level properties of composite systems only arise after coarse-graining over the lower-level properties and relational states. Coarse-graining is the result of reducing the resolving power of a theoretical representation.

The representation of the natural world provided by scientific theory becomes more accurate and informative the greater the ability of theory to discriminate between different states of a system; this is the resolving power of a theory. Increasing the resolving power of a theory has therefore typically involved identifying the increasingly smaller components of physical systems, their properties, and the relationships between them.

The flip-side of resolving power is that a macroscopic theory can only be recovered from a microscopic theory after some coarse-graining has taken place. As the resolving power of a theory is reduced, microscopic entities and classes of similar microstates merge and become indistinguishable to the macroscopic theory. As the lower-level entities merge, it is the properties and relational structure of the merged entities which the macroscopic theory characterises.

The third point is that Appleyard neglects the distinction between ontological reductionism and epistemological reductionism. Ontological reductionism merely proposes that the parts of a system, and the way in which those parts are organised and interact, uniquely determine the higher-level states and properties of the system. Epistemological reductionism, in contrast, proposes that we can always explain and predict the higher-level states and properties of a system from the parts of the system.

The latter is a much stronger claim, and due to the conceptual incompatibilities between different theories, and simple limitations in the tractability of equations when dealing with systems containing billions of particles, there's good reason to believe that epistemological reductionism is false. This, however, is consistent with the truth of ontological reductionism.

Up to this point, Appleyard's attack on reductionism and materialism is fairly conventional. In Chapters 11 and 12, however, things take a bizarre turn. Appleyard considers human creativity, and the manner in which ideas and solutions can occur to the conscious mind only when its attention has relaxed, and been directed elsewhere:

"Both the scientist and the artist are struck by the moment of inspiration...that seems to come from nowhere and to happen to them rather than being achieved by deliberate effort. The new thing pre-exists but not, perhaps, in this world," (p216).

Now, most psychologists would suggest that what happens here is that the unconscious mind is processing information while the attention of the conscious mind is directed elsewhere, and it is the unconscious mind, and its capacity for making unusual connections, which is responsible for generating such ideas and solutions. Strangely, Appleyard doesn't even consider the possibility of unconscious information processing. Instead, there is an eager leap to the suggestion that novel ideas have a supernatural source.

It is as if our minds, then, are such ontologically sharp systems that they have punctured the fabric which separates the physical world from the transcendent, and original ideas are leaking into our world like rainwater through a badly bituminised roof.

But what could this other world be? The astral plane? The spirit world? Or is it perhaps just a bog-standard supernatural deity, like one of those invented by some tribes in the Middle East a couple of thousand years ago, but now dressed-up in pseudo-intellectual aesthetic garments?

Appleyard continues: "Creative novelty is dangerous for the prevailing materialist account of the world and the mind. If reality is a chain of cause and effect going back all the way to the Big Bang and, for all we know, beyond, then newness is an impossibility, everything that happens must, somehow, be embedded in what previously happened," (p220).

Newness is inconsistent with causality? This almost seems to confuse causality with constancy. A causally closed material universe is not a universe in which everything stays the same. On the contrary, it is precisely the unfolding of those causal processes which produces the novelty in our universe. In particular, as a civilisation evolves, new patterns of brain activity evolve, and these correspond to new ideas.

Appleyard claims at the outset that "Art has always been the best guide to what we most profoundly are and what we are becoming. Writers, architects, visual artists and musicians define our species and our predicament," (p17). This attitude is problematic, however, when we recall the origin of aesthetics as a question of taste. In fact, two problems become apparent, one of which is epistemological, the other moral.

Firstly, because aesthetic judgements boil down to nothing more than embellished expressions of personal taste, they are irreducibly subjective. As a consequence, there are as many conceptions of art and aesthetics as there are aesthetically-inclined individuals. Art and aesthetics therefore fail to provide any contribution to the corpus of objective knowledge. There can be no artistic knowledge, only artistic belief.

Secondly, because aesthetic judgement is a matter of taste, the sociodynamics of human society entail that it rapidly becomes little more than a communication channel for inter-personal expressions of superiority. The aesthetically-inclined wish to express the superiority of their taste over that possessed by others, and it is here that we find the psychological root of Appleyard's belief in the "autonomy and importance of art against the claims of science," (p216).

This is the moral problem with art, and history has demonstrated that under certain circumstances, the sense of superiority engendered by the aesthetic condition can be a source of great evil.

Like Appleyard, 19th century Germany considered art to afford a superior form of knowledge to that provided by science. As Donna Cassidy writes in her biography of Marsden Hartley:

"The right-wing writer Julius Langbehn railed against the materialism of modern urban life...in his popular book Rembrandt as Educator (1890). Considered the 'Bible of a new, reformed Germany', this text, which condemned intellectualism, science, technology and modern society, participated in the larger Western critique of positivism at this time...He wanted to recover what he considered lost German virtues - simplicity, subjectivity, individuality - which he located in the volk...Langbehn placed Rembrandt and art at the center of his vision of social change: an Age of Art should replace an Age of Science," (Cassidy, p181).

In a not totally dissimilar fashion, Appleyard writes that "Art, the highest expression of the human mind, is the complex solution to the complex problem of our existence," (p247) and that "the old age of the short-term, simple solution is dying to be replaced with something much finer - the Long Now of the complex system,"(p263).

There are warnings from history about such aesthetically-motivated future visions. In Toward the Final Solution, historian G.L. Mosse attributed the provenance of anti-semitism to "the European tendency to regard humanity from an aesthetic point of view and to classify human beings according to their closeness or distance from Greek ideals of beauty." Mosse also traced the intellectual origins of the Third Reich and National Socialism back to the anti-rationalism of Langbehn et al in 19th century Germany:

"Though it is well known that Nietzsche and Wagner were among the predecessors of the movement, the intensity of German national feeling was held to be sufficient explanation for the rise of National Socialist ideology. Today we are forced to realise that a more complex cultural development gave its impress to that movement long before it crystallized into a political party. At the very center of this movement were ideas not so much of a national as of a romantic and mystical nature, part of the revolt against positivism which swept Europe at the end of the XIXth century. In Germany this revolt took a special turn, perhaps because romanticism struck deeper roots there than elsewhere. This German reaction to positivism became intimately bound up with a belief in nature's cosmic life-force, a dark force whose mysteries could be understood, not through science, but through the occult. An ideology based upon such premises was fused with the glories of an Aryan past, and in turn, that past received a thoroughly romantic and mystical interpretation." (G.L. Mosse, The Mystical Origins of National Socialism, Journal of the History of Ideas, 22(1), pp. 81-9).

Thursday, April 05, 2012

Why Health and Safety costs lives

The local level crossing comes down 4 minutes before a train arrives. It does this whether it's expecting an Intercity to charge through the station unhindered, in futile chase of the vanishing point at the horizon, or whether a dual-carriage local station-hopper is chugging slowly down the line.

About 40 cars are held during this time on each side of the crossing, so even assuming that there's only one occupant in each car, it follows that 320 minutes of dead-time are created in people's lives every time the crossing comes down. The crossing comes down on average 4 times every hour for at least 12 hours of every day, so that's about 5,606,400 minutes of dead time created by just one level crossing every year.

There's only 525600 minutes in a year, so this single level crossing creates the equivalent of more than 10 person-years of dead time, and it does this every year. That's the equivalent of going out and randomly slaughtering ten people.

Not only that, but the reason why so many people try to jump these level crossings when the barriers begin to descend, is precisely because they've experienced the ridiculously excessive safety margins endemic in modern bureaucratic culture. If the barriers came down 30 seconds before each train arrives, and people could transparently perceive that this was consistently the case, then there would be no incentive for jumping the barrier. It's the excessive safety margins which create both the incentive, and the low perceived risk for jumping a descending barrier.

For these reasons, then, modern Health and Safety is a killer.

Sunday, April 01, 2012

Sports psychology and neuroscience

This week's Autosport contains a purported explanation from sports psychologist Don Macpherson, of why Sauber's cautionary radio call cost Sergio Perez victory in Malaysia:

"Racing drivers must drive with their subconscious, the right hemisphere of the brain. The [voice in your head] lives in the left hemisphere (conscious) - for words, numbers and technical stuff.

In Malaysia, Sergio Perez was driving with his right-side brain - automatically, instinctively - when he was closing on Fernando Alonso."

This is only wrong in two respects: there is no reason to believe in the simple lateralization of brain function, and the distinction between conscious and subconscious processes is not correlated with the left and right sides of the brain.

On the general issue of brain lateralization, the current state of neuroscientific knowledge is nicely summarised on Wikipedia:

"Broad generalizations are often made in popular psychology about one side or the other having characteristic labels such as 'logical' or 'creative'. These labels need to be treated carefully; although a lateral dominance is measurable, these characteristics are in fact existent in both sides, and experimental evidence provides little support for correlating the structural differences between the sides with functional differences."

Secondly, the conscious mind is generally associated with the cortex, while the unconscious mind is associated with the cerebellum, hypothalamus and brain stem. In other words, the distinction between conscious and unconscious has nothing to do with brain lateralization.

It seems that an ability to grasp fundamental concepts and absorb simple facts is superfluous to the role of sports psychologist.