Sci-Tech Interfaces

Walking vs Running

2009-04-02T22:26:00.007+02:00

Runner's high - it's that sensation of well being that you get from intense physical effort, like endurance running. It's apparently due to the hypothalamus and the pituitary gland releasing endorphins. It's a way of injecting oneself with internally secreted stimulants. No wonder the pleasure generates by intense sports is akin to 'excitement, pain and orgasm' - dixit Wikipedia. And while this effect was baptized "runner's high" it's experienced in a whole range of sport disciplines - from boxing to swimming.

Anyway, the main subject is running - an activity which is typical to humans among primates. It distinguishes us from our cousins great apes. The chimpanzees, orangutans and gorillas are not capable of jogging like we do.

The First Runner's High: Jogging Separated Humans from Apes
by Robert Roy Brit - on LiveScience.com

This article was an eye-opener and a source of wonder for me. I was taught in biology class that the distinctive attributes of humans among primates were

the upright posture
articulate speech
work / the use of tools

I didn't give it much thought back then but now the question resonates to me clearly:
In what order ? Did the ancestors of homo sapiens start chatting with each other while they were still living in the trees ? Were their first conversations about how to use weapons or tools ?
How did the whole process of evolution take place ?

And one answer that particularly resonated with me is given in the article above:

The conventional thinking has been that running was a mere byproduct of upright walking, known as bipedalism.

But the ape-like species Australopithecus is thought to have gone bipedal 4.5 million years ago while continuing to climb trees, too. It took another 3 million years or more for Homo sapiens to evolve from Australopithecus.
"So is walking going to be what suddenly transforms the hominid body?" Bramble asks. "No, walking won't do that, but running will."
[...]

Importantly, the food that early humans could catch by simply outlasting their prey -- meat -- would have changed everything.

"What these features and fossil facts appear to be telling us is that running evolved in order for our direct ancestors to compete with other carnivores for access to the protein needed to grow the big brains that we enjoy today," Lieberman said.

So part of what make us so special - as animals - is running ! The need to outrun their prey made our human ancestors descend from the trees and evolve features that helped maintain an upright posture and excel at track and field ! They started to catch little mammals and reptiles that they could beat in an endurance challenge. This in turn provided the proteins which helped their brains grow. Apes, in comparison, could'n do that so they continued to rely of a predominantly vegetarian diet, and remained an arboreal species. With the increase in size of their brain, our ancestors started to figure out how to forge tools, which further helped them in their hunting, fishing, harvesting activities. Acquiring articulate speech was probably a subsequent evolutionary step.

"Conan the Bacterium"

2009-03-28T16:33:00.005+01:00

It's all about a microbe: a tough one ;) Deinococcus Radiodurans is then name of a bacterium species that can withstand extremely strong levels of radiation. Scientists found out it can survive conditions of radioactive exposure and chemical toxicity that proved to be lethal to any other lifeform. Hence the nickname - Conan the Bacterium - after the famous fiction character - Conan the Barbarian.

Some interesting facts:

Radiodurans was discovered in 1956 by A.W. Andersonand and belongs to a family of microorganisms, called the 'extremophiles': bugs which survive in harsh environments. The Heroic-Fantasy champion, was born in 1932, and is the brain child of American writer Robert E. Howard. His adventures take place on the Hyborian - legendary - continent.

While the barbarians are now an extinguished race (or are they ?), the extremophiles are a 'growing' category. In fact it is difficult to estimate the number of species, but it is thought that only 1% of Earth's micro-organisms have been identified so far. So there may be many many more of these bacteria species out there. In fact there are lots of them "in here" too. The human gut bacterial flora is estimated to around 500 species. Among them, the formidable Helicobacter Pylori, which lives in the highly acidic environment of the stomach.

Whereas Conan the Barbarian remains unvanquished, its bacterial counterpart proved to be a wimp: although it can handle radiation, it doesn't survive some common chemicals, like the solvent toluene. The explanation is simple: although its DNA protection mechanisms allow it to repair its genetic material - damaged by radiation - far more efficiently than humans, Radiodurans is still a living organism, so exposure to specific chemical substances can destoy it. Conan the Bacterium still holds the title of 'the world's most resistant bacterium' in the Guiness Book of Records.

Some scientists are striving to develop a genetically improved 'Super Conan' bacterium, and to use it for cheap cleanup of nuclear waste sites. Others, more modestly study Deinococcus Radiodurans in order to understand the origins of life on Earth.

A few links:
An article in Slate.fr (2009 FR)
CNRS paper (2006 FR)
Daniel Drezner's blog (2004 EN)
An article in bio-medicine.org (2000 EN)

Nuclear Power : German electronics manufacturer Siemens prefers the Rusians over the French

2009-03-04T19:58:00.003+01:00

It's the end of the cooperation between Areva and Siemens !

Power Engineering International

The Germans from Siemens A.G. have participated in a joint venture with French nuclear energy giant Areva for the past 8 years. The joint company - called Areva NP - was created in 2001, with 66% capital from Areva and 34% from Siemens.

Among the products commercialized by Areva NP are the third-generation EPR (European Pressurized Reactor) nuclear reactors.

Two of these reactors are under construction - one at Olkiluoto, Finland - the other one at Flamanville, France. Besides, Areva has signed with the Chinese electric operator CGNPC for 2 supplementary EPRs, to be located in Taishan, in the southern province of Quangdong. The deal, signed in November 2007, is worth some €8 billion ($12 billion).

Siemens will keep its 34% participation in Areva NP until 2012, but in reality, the divorce is already consumed. France has opposed an offer by Siemens to increase its participation in Areva NP. The Sarkozy government favoured concentration of French industrial actors around Areva. Bouygues and Alstom where among the government's candidates for a 'political' merger to create a nuclear power trust 100% national.

This decision prompted Siemens to turn to the russian nuclear agency, Rosatom, for a new partnership. Russian nuclear industry went a thorough overhaul in 2008, which allows Rosatom to offer a full range of solutions for nuclear power : nuclear fuel production, reactor building, operational maintenance and other services, reactor decommissioning and nuclear waste treatment.

A great setback for French nuclear industry. "A heckuva job", Mr. Sarkozy !

About Esterel

2009-01-04T23:54:00.004+01:00

I have long been nurturing a keen interest for all software that strays away from traditional software. 90% of the software currently written worldwide is

imperative programming, as opposed to functional or declarative programming
destined for sequential execution rather simultaneous / parallel execution
manipulating discrete data (discrete signals) rather emulating continuous data (analog signals)
respecting best effort execution time constraints instead of real time execution constraints (is this the same as sequential vs. parallel ? not quite : here it's about how software deals with inputs and the notion of time; there it was about how the resources are alloted to each task)

So I've looked into the reason and meaning the Esterel and Lustre languages. I have first heard about Esterel in university. I was studying telecommunications, with a major in optical, RF and microwave transmissions. So software was not really my cup of tea.

But one day the optics teacher said: "In order to become an optical networks engineer nowadays, there are a sum of skills to posess : a pinch communications theory, a drop of digital electronics, a whiff of programming".

I took a course in digital electronics, where I learned about hardware description languages, in particular Verilog and VHDL. The 'synchronous processes' paradigm that is characteristic to hardware was so much more appealing to me than old fashionned 'shoot and reload' approach of all interpreters, compilers and the like.

Later I went on to discover VHDL-AMS and the description of continuous-time, continuous-data systems. AMS stands for Analog and Mixed Signal. The world in which we live - sounds, light intensities, temperatures, concentrations, efforts, translations - are all analog signals, so suddenly software was no longer restrained to a 0 and 1 abstract space; it was so much closer to how I knew, felt and experienced the world due to my physics-oriented training.

Now back to Esterel ! Far as I have understood, it's meant to be a description language, just like VHDL, but on a higher abstraction level. It features a much facilitated description of parallelism. However Esterel is not just about specifying RTL netlists; it is meant to describe all possible finite state machines (FSM, automata), wether their implementation is to be written in software or in hardware.

"Esterel compiler[...]translates programs into C for simulation or software implementation and into Verilog or VHDL RTL-logic for hardware synthesis."

The designer can then chose which part of the automata is implemented software and which in hardware :

"One can use Esterel to first implement or simulate a system entirely in software, validate it, and then automatically turn it to hardware. Such a flow has many desirable properties, including the ability to keep a single specification for hardware and software while formally guaranteeing the same behavioral properties of the design. Furthermore, one has a lot of flexibility to partition the system description so that some of it is realized in hardware and the rest is mapped to software."

(from 'System Level Design and Verification Using a Synchronous Language', G. Berry, M. Kishinevsky, S. Singh)

In fact the role of Esterel is similar to other high level system description languages, such as SystemC and System Verilog. And its specificity with regard to those languages lies with its being a 'formally defined' language, which facilitates the formal verification of the described automata. I.E. ensuring that the computer behaves as expected, under all circumstances.

As to Lustre - it is also a synchronous programming language, but unlike Esterel - which is imperative, Lustre is a declarative language. Since it's been developped by the same company, I guess it is safe to assume that it is complementary in purpouse to Esterel.

For more insight into these languages, some in depth reading and coding practice is probably required.

Internal Combustion Engines and vibration

2008-12-28T23:26:00.000+01:00

Today I've done some reading about the conversion of mechanical effort, from a translation setting - linear applied force, and linear movement - to a rotational one : torque and spinning motion.

What I had in mind is a piston, with a connecting rod and a crank that drives a wheel around an axis. The typical mechanism you see in a steam engine.

Then, while exploring the subject, I've realised that car engines are built mainly on the same principle, although they have -nowadays - not one, but 4, 6 or 8 pistons. As I had suspected, a single piston does a very imperfect conversion of mechanical power. Some of the translational effort is lost in the process, through friction or - even worse - vibration. I found out that the supression of the vibration movements that come from piston motion in an automobile engine is quite an engineering topic. It is called engine balancing or - as refering to what it is meant to achieve instead of the process itself - engine smoothness.
Better balancing of the engine means energetic efficiency - thus lower fuel consumption, - less mechanical stress on the crankshaft and pistons - therefore a car engine that lives longer - and, last but not least, less noise and vibration for the driver to endure. The gains become all the more important when the engine is designed to run at high rev.

The balancing of an engine is mainly an issue for the engine designer - who decides how many pistons, and their relative configuration - V, W, straight or boxer - as well as complementary balancing mechanisms, such as flywheels and balance shafts. But it is also a puzzle for the mechanic who tunes the engine: the balance is initially calculated for an engine with all its original parts. If some parts are replaced or simply become loosened through use, then a retuning becomes crucial.

Your usual car cruises between 2 000 and 6 000 rpm, but Formula 1 racing monsters can handle up to 20 000 rpm. When the rev doubles the centrifugal / centripetal efforts on the rotating parts quadruple ! Needless to say that F1 cars use the most accurate balancing techniques. And in spite of that end up in a museum (at best) after only a few races - well, engine wear-off is not the only one responsible for their demise. It would be actually interesting to know what can still be used from a racing car when it is deemed to be no longer fit for competition.

Back to engine smoothing ! The subject is vast; I'll come back to it later, perhaps with some math in support, to give a feeling of the challenges involved.

Definition of an interface

2008-12-27T20:52:00.000+01:00

The blog is dedicated to displaying my personal areas of interest in science and technology, under a particular type of classification, based on interfaces between scientific domains, technology fields ar merely physical world aspects.

An academic definition of the word "interface" can be found here. What I focus on in the meaning of word interface are the "boundary surface" aspect as well as the "communication or interaction" aspects.

Let's have some examples of "interfaces" I'd like to explore in this blog.

science / technology - those two domains have a common aspect, which is the manifestation of human knowledge and intellect. However, just like two phases of chemical a substance, there are very different laws governing each of them. Science and scientists are driven by the knowledge, understanding and explanantion of the (physical, social, economic ...) world in which we live, while technology and 'techies' are bent upon acting and modeling the world to their needs, views or ambitions. But here comes into play the 'communication' and 'cooperation' meaning of interface : for science to become ever more knowledgeable, complex measurement and observation tools need to be built (like the electron microscope or the LHC); these require a great deal of technology effort. Also, science needs to rely on complex social structures and organization to provide an environment for the most talented scientists to fulfill their goals. On the other hand, complex technical realizations are upon rigourous fundamental-science studies and theories. And the social hierarchy and structures ( companies, NGOs, governments, teams ) benefit from the development of social sciences.

So, basically what characterizes an "interface" is

two domains of equivalent importance that share some common aspect
very distinct laws that govern the cores of the two domains
a vague, changing, ambiguous frontier between the domains
a continuous give-and-take exchange, communication between them

Other examples:

social sciences / exact sciences

formal sciences / natural sciences

technical language / commercial language

technical innovation / commercial innovation

Within the technology branch:

rotational motion / translational motion

air / water (or gas / liquid)

software / hardware

digital / analog

mechanical / electrical

Within sciences :

biology / chemistry

chemistry / physics