Monday 25 September 2023

Moon Article

 The Moon is Earth's only natural satellite and the fifth-largest natural satellite in the Solar System. It is the largest natural satellite in relation to the size of its planet, and the only one known to have a significant atmosphere. The Moon orbits Earth at an average distance of 384,400 km (238,900 mi), or about 30 times Earth's diameter. The Moon takes about 27.3 days to orbit Earth once.

The Moon is a tidally locked body, meaning that the same side of the Moon always faces Earth. This is because the Moon's gravitational pull on Earth's tides has slowed the Moon's rotation until it is equal to its orbital period.

The Moon is a rocky body with a diameter of 3,474 km (2,159 mi). It is about one-quarter the size of Earth and has about one-sixth of Earth's gravity. The Moon's surface is covered in craters, which were formed by asteroid and comet impacts billions of years ago.

The Moon has no atmosphere and no liquid water on its surface. However, there is evidence to suggest that there may be water ice in the Moon's polar craters. The Moon also has a very thin exosphere, which is made up of helium, argon, and neon.

The Moon has played an important role in human history and culture. It has been a source of fascination and wonder for people all over the world. The Moon has also been used as a navigational aid and a calendar.

In the 20th century, humans became the first species to set foot on another world when Apollo 11 landed on the Moon in 1969. Since then, there have been five more Apollo missions that landed on the Moon. The last Apollo mission to land on the Moon was Apollo 17 in 1972.

In recent years, there has been a renewed interest in exploring the Moon. NASA is planning to send astronauts back to the Moon in the next few years. NASA is also planning to build a lunar space station that will be used as a gateway to explore other planets and moons in the Solar System.

The Moon is a fascinating and important place. It is our closest neighbor in space and it has a lot to offer us. We are still learning about the Moon and its potential. The Moon is a key part of our future in space and it is sure to play an important role in our exploration of the cosmos.

Thursday 25 July 2019

FaceApp, The Future Of Artificial Intelligence.

Now a days we are living in the Era of technology. Technology which is changing day by day, sometimes it is helpful sometimes it is harmful. Surely we heard the name of AI (ARTIFICIAL INTELLIGENCE).
Now question arise what is the AI?

FaceApp which is trending is the best example of AI. People are sharing their old age photos on social media for fun. This is possible due to AI. The app uses artificial intelligence to create a rendering of what you might look like in a few decades on your iPhone or Android device.



This app gone viral in few days. We can say that AI is ous future, it makes our work easy may be better than human.

Artificial Intelligence refers to the simulation of human intelligence in machines that are programmed to think like humans and mimic their actions. The term may also be applied to any machine that exhibits traits associated with a human mind such as learning and problem-solving.



Artificial intelligence is based on the principle that human intelligence can be defined in a way that a machine can easily mimic it and execute tasks, from the most simple to those that are even more complex. The goals of artificial intelligence include learning, reasoning, and perception.


Monday 23 November 2015

SAND IN THE WATER




If we try to dissolve sand into water it does not dissolve but we are trying to invent some special type of method by which we can dissolve sand into water or any other liquid. The main idea works behind it is "there is interatomic space between particles of hydrogen and oxygen in water".

Sunday 15 November 2015

"HYPERSONIC SPEED"

HYPERSONIC SPEED


In aerodynamics, a hypersonic speed is one that is highly supersonic. Since the 1970s, the term has generally been assumed to refer to speeds of Mach 5 and above.The precise Mach number at which a craft can be said to be flying at hypersonic speed varies, since individual physical changes in the airflow (like molecular dissociation and ionization) occur at different speeds; these effects collectively become important around Mach 5. The hypersonic regime is often alternatively defined as speeds where ramjets do not produce net thrust.
Characteristics of flow
While the definition of hypersonic flow can be quite vague and is generally debatable (especially due to the lack of discontinuity between supersonic and hypersonic flows), a hypersonic flow may be characterized by certain physical phenomena that can no longer be analytically discounted as in supersonic flow. The peculiarity in hypersonic flows are as follows:

1-Shock layer
2-Aerodynamic heating
3-Entropy layer
4-Real gas effects
5-Low density effects
6-Independence of aerodynamic coefficients with Mach number.


  • Small shock stand-off distance

As a body's Mach number increases, the density behind the shock generated by the body also increases, which corresponds to a decrease in volume behind the shock wave due to conservation of mass. Consequently, the distance between the shock and the body decreases at higher Mach numbers.
  • Entropy layer
As Mach numbers increase, the entropy change across the shock also increases, which results in a strong  entropy gradient and highly vortical flow that mixes with the boundary layer.


  • Viscous interaction
A portion of the large kinetic energy associated with flow at high Mach numbers transforms into internal energy in the fluid due to viscous effects. The increase in internal energy is realized as an increase in temperature. Since the pressure gradient normal to the flow within a boundary layer is approximately zero for low to moderate hypersonic Mach numbers, the increase of temperature through the boundary layer coincides with a decrease in density. This causes the bottom of the boundary layer to expand, so that the boundary layer over the body grows thicker and can often merge with the shock wave near the body leading edge.

  • High temperature flow
High temperatures due to a manifestation of viscous dissipation causenon-equilibrium chemical flow properties such as vibrational excitationand dissociation and ionization of molecules resulting in convective and radiative heat-flux.

Classification of Mach regimes
Although "subsonic" and "supersonic" usually refer to speeds below and above the local speed of sound respectively, aerodynamicists often use these terms to refer to particular ranges of Mach values. This occurs because a "transonic regime" exists around M=1 where approximations of the Navier–Stokes equations used for subsonic design no longer apply, partly because the flow locally exceeds M=1 even when the freestream Mach number is below this value. The "supersonic regime" usually refers to the set of Mach numbers for which linearised theory may be used; for example, where the (air) flow is not chemically reacting and where heat transfer between air and vehicle may be reasonably neglected in calculations. Generally, NASA defines "high" hypersonic as any Mach number from 10 to 25, and re-entry speeds as anything greater than Mach 25. Among the aircraft operating in this regime are the Space Shuttle and (theoretically) various developing spaceplanes.


Similarity parameters

The categorization of airflow relies on a number of similarity parameters, which allow the simplification of a nearly infinite number of test cases into groups of similarity. For transonic and compressible flow, the Mach and Reynolds numbers alone allow good categorization of many flow cases.
Hypersonic flows, however, require other similarity parameters. First, the analytic equations for the oblique shock angle become nearly independent of Mach number at high (~>10) Mach numbers. Second, the formation of strong shocks around aerodynamic bodies means that the freestream Reynolds number is less useful as an estimate of the behavior of the boundary layer over a body (although it is still important). Finally, the increased temperature of hypersonic flows mean that real gas effects become important. For this reason, research in hypersonics is often referred to as aerothermodynamics, rather than aerodynamics. The introduction of real gas effects means that more variables are required to describe the full state of a gas. Whereas a stationary gas can be described by three variables (pressure, temperature, adiabatic index), and a moving gas by four (flow velocity), a hot gas in chemical equilibrium also requires state equations for the chemical components of the gas, and a gas in nonequilibrium solves those state equations using time as an extra variable. This means that for a nonequilibrium flow, something between 10 and 100 variables may be required to describe the state of the gas at any given time. Additionally, rarefied hypersonic flows (usually defined as those with a Knudsen number above 0.1) do not follow the Navier-Stokes equations. Hypersonic flows are typically categorized by their total energy, expressed as total enthalpy (MJ/kg), total pressure (kPa-MPa), stagnation pressure (kPa-MPa), stagnation temperature (K), or flow velocity (km/s). Wallace D. Hayes developed a similarity parameter, similar to the Whitcomb area rule, which allowed similar configurations to be compared.

Regimes

Hypersonic flow can be approximately separated into a number of regimes. The selection of these regimes is rough, due to the blurring of the boundaries where a particular effect can be found.

  • Perfect gas
In this regime, the gas can be regarded as an ideal gas. Flow in this regime is still Mach number dependent. Simulations start to depend on the use of a constant-temperature wall, rather than the adiabatic wall typically used at lower speeds. The lower border of this region is around Mach 5, where ramjets become inefficient, and the upper border around Mach 10-12.

  • Two-temperature ideal gas
This is a subset of the perfect gas regime, where the gas can be considered chemically perfect, but the rotational and vibrational temperatures of the gas must be considered separately, leading to two temperature models. See particularly the modeling of supersonic nozzles, where vibrational freezing becomes important.

  • Dissociated gas
In this regime, diatomic or polyatomic gases (the gases found in most atmospheres) begin to dissociate as they come into contact with the bow shock generated by the body. Surface catalysis plays a role in the calculation of surface heating, meaning that the type of surface material also has an effect on the flow. The lower border of this regime is where any component of a gas mixture first begins to dissociate in the stagnation point of a flow (which for nitrogen is around 2000 K). At the upper border of this regime, the effects of ionization start to have an effect on the flow.

  • Ionized gas
In this regime the ionized electron population of the stagnated flow becomes significant, and the electrons must be modeled separately. Often the electron temperature is handled separately from the temperature of the remaining gas components. This region occurs for freestream flow velocities around 10–12 km/s. Gases in this region are modeled as non-radiating plasmas.
As Mach numbers increase, the entropy change across the shock also increases, which results in a strong entropy gradient and highly vortical flow that mixes with the boundary layer.


  • Radiation-dominated regime
Above around 12 km/s, the heat transfer to a vehicle changes from being conductively dominated to radiatively dominated. The modeling of gases in this regime is split into two classes:

Optically thin: where the gas does not re-absorb radiation emitted from other parts of the gas

Optically thick: where the radiation must be considered a separate source of energy.The modeling of optically thick gases is extremely difficult, since, due to the calculation of the radiation at each point, the computation load theoretically expands exponentially as the number of points considered increases.

Next time i will share the information about the invention of hypersonic flight...
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Friday 13 November 2015

MOST RECENT

THE SQUARE


Jack Dorsey, the co-inventor of Twitter, is promoting his latest invention called the Square.
The square is a small plug-in attachment to your mobile phone that allows you to receive credit card payments.
The idea originated from Dorsey's friend Jim McKelvey who was unable to sell some glass work to a customer because he couldn't accept a particular card being used.
Accepting credit card payments for something you're selling isn't always easy, especially if you are mobile like a tradesman, delivery service or a vendor at a trade show.
This latest invention uses a small scanner that plugs into the audio input jack on a mobile device.
It reads information on a credit card when it is swiped. The information is not stored on the device but is encrypted and sent over secure channels to banks.
It basically makes any mobile phone a cash register for accepting card payments.
As a payer, you receive a receipt via email that can be instantly accessed securely online. You can also use a text message to authorize payment in real time.
Retailers can create a payer account for their customers which accelerates the payment process.
For example, a cardholder can assign a photo to their card so their photo will appear on the phone for visual identity confirmation. Mobile devices with touch screens will also allow you to sign for goods.
There are no contracts, monthly fees, or hidden costs to accept card payments using Square and it is expected the plug-in attachment will also be free of charge.
A penny from every transaction will also be given to a cause of your choice.
As with Twitter, it's anticipated that Dorsey will direct the company based upon feedback from users.
Square Inc. has offices in San Francisco, Saint Louis and New York and is currently beta testing the invention with retailers in the United States.
Source: squareup.com

Wednesday 11 November 2015

Invention Of Telescope

TELESCOPE


 In 1609 the Italian mathematician Galileo Galilei invented the telescope. With the telescope, Galileo discovered the mountains on the moon, the spots on the sun, and four moons of Jupiter.
The first Refracting telescope was invented by Hans Lippershey in 1608.
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light). The first known practical telescopes were invented in the Netherlands at the beginning of the 17th century, using glass lenses. They found use in terrestrial applications and astronomy.Within a few decades, the reflecting telescope was invented, which used mirrors. In the 20th century many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. The word telescope now refers to a wide range of instruments detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors.The word "telescope" (from the Ancient Greek τῆλε, tele "far" and σκοπεῖν, skopein "to look or see"; τηλεσκόπος, teleskopos "far-seeing") was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galilei's instruments presented at a banquet at the Accademia dei Lincei.In the Starry Messenger, Galileo had used the term "perspicillum"

HISTORY

The earliest recorded working telescopes were the refracting telescopes that appeared in the Netherlands in 1608. Their development is credited to three individuals: Hans Lippershey and Zacharias Janssen, who were spectacle makers in Middelburg, and Jacob Metius of Alkmaar.Galileo heard about the Dutch telescope in June 1609, built his own within a month, and improved upon the design in the following year. In the same year, Galileo became the first person to point a telescope skyward in order to make telescopic observations of a celestial object.The idea that the objective, or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors—reduction of spherical aberration and no chromatic aberration—led to many proposed designs and several attempts to build reflecting telescopes. In 1668, Isaac Newton built the first practical reflecting telescope, of a design which now bears his name, the Newtonian reflector.The invention of the achromatic lens in 1733 partially corrected color aberrations present in the simple lens and enabled the construction of shorter, more functional refracting telescopes. Reflecting telescopes, though not limited by the color problems seen in refractors, were hampered by the use of fast tarnishing speculum metal mirrors employed during the 18th and early 19th century—a problem alleviated by the introduction of silver coated glass mirrors in 1857, and aluminized mirrors in 1932. The maximum physical size limit for refracting telescopes is about 1 meter (40 inches), dictating that the vast majority of large optical researching telescopes built since the turn of the 20th century have been reflectors. The largest reflecting telescopes currently have objectives larger than 10 m (33 feet), and work is underway on several 30-40m designs.The 20th century also saw the development of telescopes that worked in a wide range of wavelengths from radio to gamma-rays. The first purpose built radio telescope went into operation in 1937. Since then, a tremendous variety of complex astronomical instruments have been developed.

TYPES
The name "telescope" covers a wide range of instruments. Most detect electromagnetic radiation, but there are major differences in how astronomers must go about collecting light (electromagnetic radiation) in different frequency bands.Telescopes may be classified by the wavelengths of light they detect:X-ray telescopes, using shorter wavelengths than ultraviolet light
Ultraviolet telescopes, using shorter wavelengths than visible light
Optical telescopes, using visible lightInfrared telescopes, using longer wavelengths than visible lightSubmillimetre telescopes, using longer wavelengths than infrared lighFresnel Imager, an optical lens technologyX-ray optics, optics for certain X-ray wavelengthsAs wavelengths become longer, it becomes easier to use antenna technology to interact with electromagnetic radiation (although it is possible to make very tiny antenna). The near-infrared can be handled much like visible light, however in the far-infrared and submillimetre range, telescopes can operate more like a radio telescope. For example, the James Clerk Maxwell Telescope observes from wavelengths from 3 μm (0.003 mm) to 2000 μm (2 mm), but uses a parabolic aluminum antenna.[11] On the other hand, the Spitzer Space Telescope, observing from about 3 μm (0.003 mm) to 180 μm (0.18 mm) uses a mirror (reflecting optics). Also using reflecting optics, the Hubble Space Telescope with Wide Field Camera 3 can observe from about 0.2 μm (0.0002 mm) to 1.7 μm (0.0017 mm) (from ultra-violet to infrared light).

OPTICAL TELESCOPE

An optical telescope gathers and focuses light mainly from the visible part of the electromagnetic spectrum (although some work in the infrared and ultraviolet). Optical telescopes increase the apparent angular size of distant objects as well as their apparent brightness. In order for the image to be observed, photographed, studied, and sent to a computer, telescopes work by employing one or more curved optical elements, usually made from glass lenses and/or mirrors, to gather light and other electromagnetic radiation to bring that light or radiation to a focal point. Optical telescopes are used for astronomy and in many non-astronomical instruments, including: theodolites (including transits), spotting scopes, monoculars, binoculars, camera lenses, and spyglasses. There are three 

main optical types:
The refracting telescope which uses lenses to form an image.
The reflecting telescope which uses an arrangement of mirrors to form an image.
The catadioptric telescope which uses mirrors combined with lenses to form an image.Beyond these basic optical types there are many sub-types of varying optical design classified by the task they perform such as astrographs, comet seekers, solar telescope, etc.
At the photon energy of shorter wavelengths and higher frequency, fully reflecting optics rather than glancing-incident optics are used. Telescopes such as TRACE and SOHO use special mirrors to reflect Extreme ultraviolet, producing higher resolution and brighter images than otherwise possible. A larger aperture does not just mean that more light is collected, it also enables a finer angular resolution.Telescopes may also be classified by location: ground telescope, space telescope, or flying telescope. They may also be classified by whether they are operated by professional astronomers or amateur astronomers. A vehicle or permanent campus containing one or more telescopes or other instruments is called an observatory.


RADIO TELESCOPES

Radio telescopes are directional radio antennas used for radio astronomy. The dishes are sometimes constructed of a conductive wire mesh whose openings are smaller than the wavelength being observed. Multi-element Radio telescopes are constructed from pairs or larger groups of these dishes to synthesize large 'virtual' apertures that are similar in size to the separation between the telescopes; this process is known as aperture synthesis. As of 2005, the current record array size is many times the width of the Earth—utilizing space-based Very Long Baseline Interferometry (VLBI) telescopes such as the Japanese HALCA (Highly Advanced Laboratory for Communications and Astronomy) VSOP (VLBI Space Observatory Program) satellite. Aperture synthesis is now also being applied to optical telescopes using optical interferometers (arrays of optical telescopes) and aperture masking interferometry at single reflecting telescopes. Radio telescopes are also used to collect microwave radiation, which is used to collect radiation when any visible light is obstructed or faint, such as from quasars. Some radio telescopes are used by programs such as SETI and the Arecibo Observatory to search for extraterrestrial life.

X-RAY TELESCOPES

X-ray telescopes can use X-ray optics, such as a Wolter telescopes composed of ring-shaped 'glancing' mirrors made of heavy metals that are able to reflect the rays just a few degrees. The mirrors are usually a section of a rotated parabola and a hyperbola, or ellipse. In 1952, Hans Wolter outlined 3 ways a telescope could be built using only this kind of mirror. Examples of an observatory using this type of telescope are the Einstein Observatory, ROSAT, and the Chandra X-Ray Observatory. By 2010, Wolter focusing X-ray telescopes are possible up to 79 keV.

GAMMA-RAY TELESCOPES
Higher energy X-ray and Gamma-ray telescopes refrain from focusing completely and use coded aperture masks: the patterns of the shadow the mask creates can be reconstructed to form an image.X-ray and Gamma-ray telescopes are usually on Earth-orbiting satellites or high-flying balloons since the Earth's atmosphere is opaque to this part of the electromagnetic spectrum. However, high energy X-rays and gamma-rays do not form an image in the same way as telescopes at visible wavelengths. An example of this type of telescope is the Fermi Gamma-ray Space Telescope.The detection of very high energy gamma rays, with shorter wavelength and higher frequency than regular gamma rays, requires further specialization. An example of this type of observatory is VERITAS. Very high energy gamma-rays are still photons, like visible light, whereas cosmic rays includes particles like electrons, protons, and heavier nuclei.A discovery in 2012 may allow focusing gamma-ray telescopes.[17] At photon energies greater than 700 keV, the index of refraction starts to increase again

HIGH-ENERGY TELESCOPES

High-energy astronomy requires specialized telescopes to make observations since most of these particles go through most metals and glasses.In other types of high energy particle telescopes there is no image-forming optical system. Cosmic-ray telescopes usually consist of an array of different detector types spread out over a large area. A Neutrino telescope consists of a large mass of water or ice, surrounded by an array of sensitive light detectors known as photomultiplier tubes. Energetic neutral atom observatories like Interstellar Boundary Explorer detect particles traveling at certain energies.

Tuesday 10 November 2015

Some Heat Related Terminology

THERMODYNAMICS


  1. The branch of physical science that deals with the relations between heat and other forms of energy (such as mechanical, electrical, or chemical energy), and, by extension, of the relationships between all forms of energy.

  2. Heat is energy can be converted from one form to another, or transferred from one object to another. For example, a stove burner converts electrical energy to heat and conducts that energy through the pot to the water. This increases the kinetic energy of the water molecules, causing them to move faster and faster. At a certain temperature (the boiling point), the atoms have gained enough energy to break free of the molecular bonds of the liquid and escape as vapor.
  3. Specific heat

    The amount of heat required to increase the temperature of a certain mass of a substance by a certain amount is called specific heat, or specific heat capacity, according to Wolfarm Research. The conventional unit for this is calories per gram per kelvin. The calorie is defined as the amount of heat energy required to raise the temperature of 1 gram of water at 4 C by 1 degree. 
    The specific heat of a metal depends almost entirely on the number of atoms in the sample, not its mass.  For instance, a kilogram of aluminum can absorb about seven times more heat than a kilogram of lead. However, lead atoms can absorb only about 8 percent more heat than an equal number of aluminum atoms. A given mass of water, however, can absorb nearly five times as much heat as an equal mass of aluminum. The specific heat of a gas is more complex and depends on whether it is measured at constant pressure or constant volume.
  4. Thermal conductivity

    Thermal conductivity (k) is “the rate at which heat passes through a specified material, expressed as the amount of heat that flows per unit time through a unit area with a temperature gradient of one degree per unit distance,” according to the Oxford Dictionary. The unit for k is watts (W) per meter (m) per kelvin (K). Values of k for metals such as copper and silver are relatively high at 401 and 428 W/m·K, respectively. This property makes these materials useful for automobile radiators and cooling fins for computer chips because they can carry away heat quickly and exchange it with the environment. The highest value of k for any natural substance is diamond at 2,200 W/m·K.
    Other materials are useful because they are extremely poor conductors of heat; this property is referred to as thermal resistance, or R-value, which describes the rate at which heat is transmitted through the material. These materials, such as rock wool, goose down and Styrofoam, are used for insulation in exterior building walls, winter coats and thermal coffee mugs. R-value is given in units of square feet times degrees Fahrenheit times hours per British thermal unit  (ft2·°F·h/Btu) for a 1-inch-thick slab.


Newton's Law of Cooling

In 1701, Newton first stated his Law of Cooling in a short article titled "Scala graduum Caloris" ("A Scale of the Degrees of Heat") in the Philosophical Transactions of the Royal Society. Newton's statement of the law translates from the original Latin as, "the excess of the degrees of the heat ... were in geometrical progression when the times are in an arithmetical progression." Worcester Polytechnic Institute gives a more modern version of the law as "the rate of change of temperature is proportional to the difference between the temperature of the object and that of the surrounding environment." 
This results in an exponential decay in the temperature difference. For example, if a warm object is placed in a cold bath, within a certain length of time, the difference in their temperatures will decrease by half. Then in that same length of time, the remaining difference will again decrease by half. This repeated halving of the temperature difference will continue at equal time intervals until it becomes too small to measure.