?Do you know ? To what depths do we find oil

The exploited reservoirs are between 600 and 8000 meters deep. But there are deeper deposits 

In 2009, it was discovered in the Gulf of Mexico as an oil field 1260 meters of water and reaching 10,600 meters deep. The presence of oil at such a depth was unimaginable ago thirties. How far in do you find

The oil resulting from the degradation of organic waste, mostly of vegetable origin, under the action of heat. But the temperature increases with depth, 30 ° C per kilometer on average. Buried in a sedimentary rock (the "bedrock"), organic debris is first transformed into a carbonaceous solid called kerogen, which coal is a variety, then give either oil and some gas (between 80 ° C and 150 ° C), or just gas (above 150 ° C). We deduce that the 

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?Maths : The challenge for the sixth crown , it can be

Can a plane figure pave a large area without it being possible to pave the entire plan? This problem called Heesch landed since 1968.

Mathematicians interested in tilings of plane geometric shapes as simple as possible. They rank considering their symmetry, design algorithms that discover new, study forms allowing only aperiodic patterns, etc. Alongside these classic problems, some not address what happens on the entire plan, but what is happening locally around a point or a pad: these are the problems of entourages. We present two. The first is solved today. The second, despite steady progress, remains mysterious.

Let's start with a basic conundrum in appearance. A flat shape we give a pad P. Can we totally surround a crown composed of copies of P, leaving no space between pavers used? What is the minimum number of copies of P needed for such surroundings?

A square paved surrounds without difficulty six identical squares (below, a), and is the minimum; best, all rectangle (! not square) is surrounded by four copies of itself (b); more preferably, some pavers surround with only three copies of themselves (c).

Avoid any misunderstanding about the word crown. The ring around a block P must have a certain non-zero thickness e: the minimum distance between a point external to the blocks and a central point of the pad P must always be greater than e. Pavers around a block P (or a set of blocks E) are considered a crown for P (or E) if the removal of a single pad of the crown is contacted outside the box paved with the central pad (or E).

To find out if it is possible to surround a pad P by a ring of two P cobblestones, take a pen and paper and try! (See figure below if you can not do.)

The pentagon Heesch: a single crown

The second issue that will occupy around us originates a small German book published in 1968 when the mathematician Heinrich Heesch (1906-1995) formulated an unexpected remark. He presented a pentagon with angles 90 °, 150 °, 90 °, 150 ° and 60 ° and with the strange property: a copy of the pentagon is surrounded Heesch perfectly without overlapping or space left empty by six seven or eight copies of itself forming a crown, and yet it is impossible to carry out a second ring around the first. One checks without difficulty ...

Jean-Paul Delahaye

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The problem sudoku : Tips , solve , calculations , illusion

The data of 16 digits in a Sudoku is insufficient for solving the problem is unique. To prove this, it was necessary to list all the grids, using tips to shorten the calculations

It is an illusion to believe that the power of the machines dispense us from thinking. About the problem of minimum data sudoku, we will see that the limits of feasible soon reached, and that for the push, it takes ingenuity, mathematics and still a lot of patience.

Remember the rules of Sudoku and fix some terms. A "complete Sudoku" is a square table 9 March 9 = 81 squares, each containing a number from 1 to 9 and such that:

(A) each row and each column contains each digit exactly once;

(B) each subarray 3 3 3 (result of the cutting of the gate into nine squares of nine squares) contains each digit exactly once.

A partial grid is a "correct sudoku problem" if there is a unique way to complete the grid in a complete Sudoku, which is the goal of the game.

Specify that sudoku, the computer wins on humans: there are many programs that allow the computer to beat the best human speed. Good programs are the solution to a problem, as difficult as it is, in less than a millisecond. So we play for fun exercise.

When looking to make a statement, if you specify too few cases, partial grid is not correct the problem (that is obvious if one retains only one), as several solutions are possible. In newspapers, the proposed grids have about 25 boxes filled. It is known however that there are correct grids sudoku with only 17 data.

The problem of minimum data is: What is the smallest number of data a correct sudoku problem?

Example 17 shows that data that minimum is 17 or less. It has long sought, unsuccessfully, to 16 problems correct data; so we conjectured that 17 is the answer.

At least 16 or 17 boxes?

The problem remained open until, in December 2011, the answer is provided by Gary McGuire, of the University of Dublin, and his team. Following a spread calculation on a year corresponding to 800 years of computing a single processor, the conclusion was that there are no correct grid sudoku data 16 and thus the minimum number of data a correct sudoku problem is 17.

This is a mathematical theorem, and since this is the mathematical question concerning the sudoku that required the most effort, will be called "The theorem sudoku". The work that led to the state is a demonstration. As now occurs increasingly often, it is a proof with a computer. The detailed steps in the calculation has not been published because it would give a document of colossal length. The article reporting the evidence is therefore that the description of the method used, including, among others, statements and demonstrations purely mathematical propositions helpful, but not enough information so that we can verify the theorem without any reprogramming and recalculate.

Preliminary versions of the article had been available for a while, but it was published in its final form June 12, 2014, in the journal Experimental Mathematics. Despite this official publication, essential for a result to be considered ... 

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Welcoming super-Earths , Exciting details , So nice

There are undoubtedly countless extrasolar planets. But what do they look like? Models suggest that many of them would be similar to the Earth, and could harbor life

You are contemplating the night sky. You look in the direction of a star around which revolves, have you read a particular planet status. Even if you can not see - you see only the star itself - you know it is several times larger than Earth and essentially consists of rocks. Sometimes earthquakes shake the surface, which is largely covered with oceans. Its atmosphere is not so different from what we breathe, and its sky is swept from frequent storms and often obscured by volcanic ash. Home she lives? According to scientists, it is not impossible ...

This astronomical dream could soon become reality. Although most of the 500 extrasolar planets discovered to date are gas giants like Jupiter instead, astronomers began to discover some - notably through the European space telescope CoRoT - which might not be very different from Earth. And the American Kepler Space Observatory, launched last year, probably discover more.

Of course, these exoplanets are in light years, so that even our most sophisticated telescopes are not able to discern the details of their surface (mountains, clouds, seas, etc.). Maybe they can do forever. In general, we can only highlight indirectly the presence of a planet, and estimate its mass and size of its orbit. In some cases, the instruments were able to obtain information on the diameter of the planet and some other details. Thus crudely known atmospheric composition and dynamics of the winds of some gas giant exoplanets.

We are far from precise measuring data on the geology, chemistry or other characteristics of exoplanets. Yet from some things, researchers are able to draw complex portraits of these distant planets, using theoretical models, numerical simulations and even laboratory experiments, combined with established knowledge for the Earth and the other planets of the solar system.

In our research, for example, we modeled the composition of planets similar to Earth. We found that such planets even when they are much more massive than our own, seem geologically active and have an atmosphere and a climate that could be favorable to life. In fact, the Earth may be located at the lower limit of the possible mass range for a planet to be habitable. In other words, if the Earth were a little smaller, it would have become as barren as Mars or Venus.

The first super-Earths

The first extrasolar planet was discovered in the mid 1990s by the "radial velocity" method, which is to detect the presence of a planet by its gravitational effects on its star. The gravity of the planet prints a slight rocking motion to the star; movement that is detected as a shift of the spectrum of the sun.

In the early days, some researchers wondered if these were the result of physical oscillations of the star or the presence of orbiting planets. There are about ten years, one of us, D. Sasselov, while specialist variable stars, helped to show that the oscillations were well caused by planets, thus validating the radial velocity method.

D. Sasselov then joined the project of the Kepler Space Observatory, designed to search for exoplanets. Kepler was finally put into orbit in 2009. As CoRoT, it is designed to detect planets by the transit method, that is to say by observing the brightness of small periodic cuts of a star when a planet in orbit passes in front of her. The Kepler telescope is pointing to a small region of the sky near the constellation Cygnus. Its wide-angle camera will follow approximately 150,000 stars continuously for three years. Kepler is expected to find hundreds of new planets, some as small as Earth.

From the earliest stages of mission planning, D. Sasselov realized that scientists would not know necessarily exploit the mass of data produced by Kepler. For example, nobody had then modeled the process ...

Source : For the science

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Culvert Bridges: The optimum combination of strength, flexibility and performance

Canadian corrugated steel pipe products are available in a variety of sizes, corrugation profiles, thicknesses and coatings to suit virtually any application - stormwater, highway construction, railway, mining and forestry challenges. We manufacture a complete range of pipe systems to handle every need and budget:

The optimum combination of strength, flexibility and performance

Corrugated Steel Pipe (CSP) is the material of choice for Culvert Bridge projects. It will not crack under impact loads or vibrations due to the inherent strength of steel and the flexibility of the corrugated pipe section. The high ring compression of the pipe absorbs and transfers the load to the surrounding soil around the entire circumference. The beam strength maintains the grade and line of the structure by bridging inequalities of the trench bottom and side fill.

Benefits

• Economical, strong, lightweight and easy to install
• Variety of sizes, thicknesses and materials
• Complete line of standard and specialized fittings and accessories
• Available in Round Pipe or Pipe Arch Profiles
• Can be used to reline existing systems
• Full engineering support and field service
• Approved to CSA Standard G401-07

Applications

• Culverts
• Drainage Systems
• Stormwater Systems
• Fish Passages
• Conveyor Covers and Overcasts
• Ventilation Systems
• Utilidor Systems
• Culvert Relines

Soil conditions and a variety of other site/application factors can influence your choice of CSP coatings. An environmental assessment will help you select the appropriate coating to meet your Design Service Life requirements.

Solve your stormwater challenges with the improved hydraulics of Hi-Flo Pipe.

Hi-Flo Pipe is an innovative flexible metal pipe that combines the proven strength of corrugated metal pipe with the flow capacity of a smooth inner wall. Economical and easy to install, Hi-Flo delivers the recommended Manning’s ‘n’ of 0.013 or better, and stands up to the most aggressive environments.

Benefits

• Smooth interior surface for superior hydraulics
• Economical, strong, lightweight and easy to install
• Reduced trench excavation and bed preparation
• Variety of sizes, thicknesses and materials
• Full range of fittings and accessories
• Long design service life expectancies
• Can be used to reline existing systems
• Full engineering support and field service
• Approved to CSA Standard G401-07, OPSD Standards 805-030/805-040, and ASTM Standards A760/A796

Applications

• Pipes and Culverts
• Drainage Systems
• Stormwater Systems

Source : AIM

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Where does the water in the oceans?

Am I right to think that, since the formation of the atmosphere as we know it today, the amount of water on Earth has remained the same except for the" rejected "outside the atmosphere by astronauts?

If we took certain liberties in interpreting the issue, we could probably answer something like: "Yes, roughly." The total amount of water present on Earth (the "hydrosphere") today is essentially the same since the atmosphere is pretty much what it is today. We are talking about a period dating back a few hundred million years to have concentrations of nitrogen and oxygen, more or less comparable to those of today (78% and 21%), but in regarding the amount of water on Earth, there is good reason to believe it is less stable for much longer than that -to only a few hundred million years after the formation of the planet, which dates back to 4.5 billion-years, said the professor of geology at the University Laval François Huot.

But now, and that is what chicote, the question of our reader is phrasee so that itsuggests that the hydrosphere is a completely closed and sealed system. Which is far from being the case. In fact, only systems closed in this story are international gearthat is sent into orbit and the Space Station. Apart from slight losses with waste water,we confirms to the Canadian Space Agency, not a single drop of H2O sweat flares, theSSI or combinations of astronaut. To say everything, even the urine of astronauts isrecycled water.

Now, on the floor of the cows, the hydrosphere fluctuates constantly since the dawnof time. Of course, on the total amount of water, these variations and these exchangeswith the space is tiny to insignificance, but they have not always existed.

It was long believed that the formation of the Earth was "dry", meaning that there wasno water at the birth of our planet, or that the little bit of H2O this would havevanished by the intense heat that prevailed here down at this time. Hydrosphere, it was believed, would have happened or may have formed later, possibly by thebombardment of meteorites - some of which, "carbonaceous chondrites", maycontain up to 20% water.

Finally, include that even when she stays on Earth, water is not immune to the changes: plants and cyanobacteria have ceased to turn into sugar during photosynthesis. So from this point of view, the hydrosphere is not perfectly fixed.

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Manipulated light projections become 3D-printed jewellery with Tactum

Digital research studio Madlab has developed a system that combines projection mapping with depth and motion sensing technologies to create customised jewellery and other items worn around the wrist.

Called Tactum, the system generates interactive projections that wrap around the topography of the user's arm, which can be 3D-scanned in advance for added accuracy. These images respond to gestures that enable the real-time modelling of wearable objects.

The system ensures that no matter how much the form is manipulated, it will always be produceable with a 3D printer and the final object will fit the user.

"Pre-scanning the body is not entirely necessary when designing a wearable in Tactum," said the studio. "However, it ensures an exact fit once the printed form is placed back on the body."

Once completed, the designs can be exported as data files to a variety of different types of printer.

The first prototypes for Tactum have relied on depth and motion sensors in existing devices, like a Microsoft Kinect, to map the geometry of the body as well as track the hand gestures like pinching and pulling used to manipulate the design.

These sensors feed the information on each gesture into a modelling programme to make live adjustments to the design, which are projected back onto the skin, creating a loop of information.

Hard constraints can be programmed in to fit the projections to specific parameters – for example, the exact dimensions of an existing watch face that must fit into a strap designed using Tactum.

This means imprecise human gestures, which are only accurate to the size of a fingertip, can be combined with the precision necessary for designing around an existing object.

"Between the 3D scan, the intelligent geometry, and intuitive interactions, Tactum is able to coordinate imprecise skin-based gestures to create very precise designs around very precise forms," explained the studio.

So far the team has explored the project through two prototypes. The first used a Microsoft Kinect sensor to detect and track skin gestures, and a Microsoft Surface Pro 3 tablet as an off-body display for presenting the digital geometry to the designer.

The second prototype switched to an above-mounted Leap Motion Controller for tracking the gestures, and showing them directly on the skin.

"While this sensor provided more robust hand and arm tracking, the gesture detection was more robust with the Kinect," said Madlab. "The second prototype also switched from an auxiliary to mapping and projecting geometry directly onto the body."

The results of the team's experiments and detailed technical information on each part of the process have been published as a research document.

The technology has already been used to create a new watch strap for the Moto 360 Smartwatch.

The position and orientation of the watch face on the wrist, as well as the overall form of the band, were determined by using hand gestures.

The exact measurements and tolerances for the clips to hold the watch face – and the clasp to close the band onto the arm – were pre-determined in the software programming, which was set before the light projection design process began.

                       Nylon and rubber print made from a Selective-Laser Sinter (SLS) 3D printer

A series of test artefacts has also been created to demonstrate the technology with different kinds of interactive geometries, materials, modelling modes and fabrication machines.

These include a PLA plastic print made on a standard desktop 3D printer, a nylon and rubber print created with a Selective-Laser Sinter (SLS) 3D printer, and rubbery print using a Stereolithography (SLA) 3D printer.

Rubbery print made from a Stereolithography (SLA) 3D printer

Tactum was presented at the SXSW Interactive festival in Austin, Texas, earlier this year

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