Wednesday, 25 February 2015

Nature Of Light

theory of light

Light and related phenomena have always had a great fascination for humans. Just the daily observation of day and night - light and dark - and the twinkling of stars suggests, the fascination this must have had on early humans. The optical color outdoor games such as Halo, Rainbow and Northern Lights, win a majority of their enchantment by the luminosity of the associated phenomena. So it is not surprising that mankind busy early with light and the history of light is closely linked with the history of physics.

Probably the earliest tradition of applications of optics exists from antiquity. First scientific papers come from the Arab world of the Middle Ages. In the 13th century that Roger Bacon to find systematic studies of refractive lens maker equation. Based on this, the first glasses were developed in the 15th century. In accordance with the principles of geometrical optics were known in the 17th century. Reflection and refraction were understood and most atmospheric optical phenomena, such as the emergence of the rainbow could be explained.

The question of the nature of light was detected only in the 18th century and also the same central element of a fierce debate. On the one hand there were the schools to the Dutchman Christian Huygens and the Englishman Robert Hooke. Both interpretations of light as a wave, similar to how it was used, for example, of water waves. The other school was led by Isaac Newton. In keeping with its Newton's laws and their mechanical interpretation of the world as he understood light particle, which divided by their different pulse in the different colors.

These views were manifested by the postulation of Maxwell's equations in which James C. Maxwell had 1864 combined electric and magnetic phenomena in four equations. Through the clever manipulation he had encountered two wave equations, so that the existence of waves seemed possible, which were characterized by an oscillation of electric and magnetic fields. A short time later, Heinrich Hertz actually managed the experimental proof of this electro-magnetic waves. Thus, it became clear that light was a special form of this new wave. The electromagnetic spectrum spans an enormous frequency or wavelength range. The visible light is only a very small proportion of this total area. It also includes radio waves, microwaves, infrared, ultraviolet, X-rays and gamma rays it.

Synchronous Motor


Synchronous motors are a type of alternating current motor in which the rotation of the shaft is synchronized with the frequency of the feed stream; the rotation period is exactly equal to an integer number of cycles CA. Its rotation speed is constant and depends on the frequency of the mains voltage to which it is connected and the number of pole pairs of the motor, this speed being known as "synchronous speed". This type of engine has electromagnets in the stator of the motor create a

Rotating magnetic field in time synchronicity at this speed.

The mathematical expression that relates the speed of the machine with the above parameters is:

n = \ frac {60 \ cdot f} {P} = \ frac {120 \ cdot f} {p}

f: frequency of the network that is connected machine (Hz)
P: Number of pole pairs having the machine
p: Number of poles having the machine
n: Synchronous speed of the machine (RPM)

For example, if a machine has four poles (two pole pairs) connected to a 50 Hz grid, the machine will operate at 1500 rpm.

They work much like an alternator. Within the family of synchronous motors must distinguish:

Synchronous motors.

Asynchronous motors synchronized.
The permanent magnet motors.
Synchronous motors are called so because the rotor speed and the speed of the stator magnetic field are equal. Synchronous motors are used in large machines with a variable load and need a constant speed.

Braking phase synchronous motor 

Generally, the desired speed of this engine is adjusted by a rheostat. The synchronous motor, when it reaches the critical torque stop, not being the most orthodox way to do it. The critical torque is reached when the engine load exceeds the allocated torque. This causes overheating which can damage the engine. The best way is to vary the load until the current consumption of the network as low as possible, and then disconnect the motor.

Another way, and most common, is regulating rheostat thereby vary the intensity and can disconnect the motor safely.

Monday, 23 February 2015

Education in Pakistan


Education in Pakistan is under the supervision of the Ministry of Education and administered by the four provinces and four federal territories. According to the Pakistani constitution, education is free for all children, both primary and secondary level and is compulsory until age 16.

The education system in Pakistan is divided into six levels: pre-primary (prep classes), primary education, grades 1 to 5; middle school, grades six through eight; high school, ninth and tenth grades, ultimately leading to the award of Certificate of Secondary School; the middle school, grades eleven and twelve, leading to the award of Higher Secondary School Certificate and tertiary or university programs where students can earn bachelor's and graduate in a variety of academic and professional education fields.

 Some private schools in Pakistan also provide a parallel system of secondary education, which is based on the curriculum of Great Britain and administered by the Cambridge International Assessments.

After independence from Britain, Pakistan had only one university, but today there are 136 universities in operation, 74 public and 62 private, which together serve more than one million students each year.

Despite recent advances in education, Pakistan still faces many challenges and problems, such as poverty, sectarian violence, poor teacher training, lack of resources and discrimination, especially against students. At present, the adult literacy rate in the country is only 58 percent (69 percent for males and 45 percent for women), well below the world average.

Twisted Pair Cabling


In its simplest form, the twisted pair cable contains two copper strands intertwined twisted and covered with insulator.

There are generally two types of twisted pair:

Shielded pairs (STP: Shielded Twisted Pair)
Unshielded pair (UTP: Unshielded Twisted-Pair).

A cable is often made from several twisted pairs grouped and placed inside of the protective sheath. Striping helps to remove noise due to contiguous pairs or another source (motors, relays, transformers).
Twisted pair is therefore suitable for local networking a small park with a limited budget and simple connections. However, over long distances with high data rates it does not guarantee data integrity (that is to say, the transmission without data loss).

Unshielded twisted pair (UTP)

UTP obeys the 10BaseT specification. This is the twisted pair type most used and most widespread for local networks. Here are some features:

Most telephone installations use UTP cable. Many buildings are pre-wired for this type of installation (often in sufficient numbers to meet the future needs). We must be careful, however, to the number of twists and other electrical characteristics required for quality data transmission.

The major problem is that the UTP cable is particularly subject to interference (a signal line mixing with those of another line). The only solution lies in the armor.

The shielded twisted pair (STP)

The STP (Shielded Twisted Pair) uses a higher quality copper sheath and more protective than the jacket used by UTP cable. It contains a shroud between the pairs and around pairs. In the STP cable, copper son of a pair are themselves twisted, which provides STP cable excellent shielding, that is to say, better protection against interference). On the other hand it allows faster transmission and a longer distance.

Sunday, 22 February 2015

Study At Hong Kong

hong kong

Hong Kong is not only a place to be visited by tourists as it is an educational center that brings together people from around the world. It houses some of the best universities in Asia and the world, thanks to international standards that keep these institutions. Each year, an increasing amount of foreign students arriving for higher education courses, from neighboring nations and not so close. Here, we describe the procedures that must be performed to request a student visa in that region:

1. Get a sponsor

Before applying, you must nominate a local sponsor; which may be the school that admitted you as a student, or a person over 18 who is a resident of Hong Kong and financially able to support you throughout the race. In such a scenario, you must complete and fill a "Statement of Financial Sponsor"; and your parents / guardians must authorize sponsorship, especially if you're still underage.

2. Fill out the necessary forms

The visa applicant must complete the form ID 995A, while the sponsor does the same with the 995B ID. Both can be downloaded online through the website:, or sought in the following offices:

Immigration Department Headquarters
Immigration Division of the Office of Government of the Special Administrative Region of Hong Kong (HKSAR) in Beijing
Immigration Branches
Chinese Diplomatic and Consular Missions Abroad
Economic and Trade Office in Hong Kong in Guangdong

3. Attach these documents

Transcripts, awards and certificates
Photocopy of your admission letter issued by a university in Hong Kong, and your letter of acceptance to the specific course
Photocopy of the travel document containing personal data, issue date, expiration date and / or details of previous visas (if applicable)
A passport size photograph
Test your financial situation, as grants obtained, bank statements, passbooks, etc. The minimum required amount of money is $ 120,000 Hong Kong or the equivalent in any foreign currency
Photocopy of academic results
Photocopy of other qualifications such as IELTS or TOEFL tests
Photocopy of identity card or equivalent
Photocopy of passport
Visa Application Forms and Sponsorship Declaration duly completed
Copy of notice of telegraphic transfer / receipt

4. Submission requirements

Do it directly to the Chinese Embassy in your country of residence. Anyway, look for more information on the local website of the agency.

5. Wait for confirmation

Once your application is received by the Immigration Department of Hong Kong (HKID) will have to wait about two months for the reply. If yes, you will be notified by email where you will indicate where withdraw the visa label.

Cash Accounting


Cash (accounting)

The fund represents cash that the company has. The cash is an asset account that measures changes in cash during the year and the amount at the end of the year.

Types of cash in accounting

1 Issues in cash
2 Using the cash account
2.1 Finance and cash
2.2 Cash accounting

Issues of the body

The cash account is used to represent the value of cash. It has the characteristic of not affecting a particular recipe to a particular expense. This is the principle fund unit. An analysis of this particular check the nature of the cash flows in order to check possible abuse of corporate assets, flights ...

The advantage of a cash only basis is objectivity since there are no charges and calculated products.

The fund is available in the balance sheet as well as bank accounts and certain securities. The fund is therefore a basic part of the cash flow of the company. This account does not require restatement in the construction of functional assessment or cash tables. An effective way to analyze the fund is to achieve a cash flow budget.

Friday, 20 February 2015

The Blood Circulation


The circulatory system or circulatorioa system is the anatomical structure composed of the cardiovascular system leading ago and circulate blood, and lymphatic system leading lymph unidirectionally toward the heart. In humans, the cardiovascular system consists of the heart, blood vessels (arteries, veins and capillaries) and blood, and lymphatic system is comprised of lymphatic vessels, lymph, the lymphoid organs (spleen and thymus), bone marrow, lymphoid tissues (such as the amygdala and Peyer's patches) and lymph.

Blood is a fluid type specialized connective tissue with a liquid colloidal matrix, a complex and a characteristic red color constitution. Is a solid phase (formed elements, including leukocytes (white blood cells), erythrocytes (or red blood cells), platelets and a liquid phase, represented by blood plasma.

Lymph is a clear fluid that runs through the lymphatic vessels and pigments generally lacks. It occurs after the excess fluid from the capillaries into the interstitial or intercellular space, and is picked up by the lymphatic capillaries that drain thicker lymph vessels to converge in ducts that empty into the subclavian veins.

The main function of the circulatory system is to pass nutrients (such as amino acids, electrolytes and lymph), gases, hormones, blood cells, among others, body cells, metabolic waste collected to be eliminated by the kidneys after in the urine and exhaled air in the lungs, rich in carbon dioxide (CO2). In addition, defends the body against infection and helps to stabilize the temperature and pH to maintain homeostasis.

Study At Belgium


A stay of more than 90 days is considered long stay. In this case, a national visa must be requested. The treatment period is in most cases several months. The city administration in Belgium, changed the visa for residence permit at the time the student reaches Belgium and register. With a short-stay visa can not acquire a residence permit.

1. Information on some documents to Colombian applicants for long-stay visa

Any document civilian: birth certificate or marriage registration.

Certificate of Legal History (this document is downloaded from the website of the National Police of Colombia)

Authorization departure of a minor

Of-court statement (statement of cohabitation, statement of economic dependence, etc.)

Any document issued by Colombian authorities require apostille apostille translation and translation.

Translation and apostille documents issued by Colombian authorities takes place in the Ministry of

Foreign Affairs of Colombia.

These documents are translated into French, Dutch or German.

The list of official translators is on the website of the Ministry of Foreign Affairs of Colombia.

Thursday, 19 February 2015

Study At China


To apply for a student visa is necessary to have been admitted to a Chinese school and received the acceptance letter along with the application form corresponding visa, JW201 or JW202 called, depending on the case. To start the process, we would go to the Chinese Embassy or Consulate and submit relevant documents requested depending on the country of origin.

Normally, you must submit a recent photograph, a passport valid for at least six months at the time of the application, original and copy of the letter of admission to relevant, original and copy of the completed visa application called correctly and Foreigner Physical Examination Record for Foreigners Medical Report or studies. In any case, recommend contacting the embassy to have complete assurance what procedures we follow are and what is the cost of the visa

International students need to submit documentation of their health status. They must submit a medical report and the results of a blood test both your visa application and arrival in China, where they must submit two reports to the quarantine office for proper verification. Those who do not meet the medical requirements will have to retake the exam.

Difference Between Alpha Beta And Gamma Rays


The Alpha:

The Alpha rays are helium nuclei of atoms with positive charge, which do not penetrate beyond the surface of the skin and the sheet of paper can stop completely. really should talk about alpha particles.

The Beta:

Beta radiations are electrons, negative particles, arising from the decay of neutrons in the nucleus. are more penetrating than alpha radiation and the can be introduced from one to two inches in water or human tissues. a sheet of aluminum of a few millimeters thick is sufficient to stop it.

The Gamma:

The gamma rays are the most pervasive types of radiation described. The gamma radiation often accompanies and sometimes beta to alpha. Gamma rays easily penetrate the skin and other organic substances, which can cause serious damage to internal organs.

Wednesday, 18 February 2015

Alessandro Volta


Alessandro Volta was born in Lombardy, Italy, on February 18, 1745, within a noble family in Como, Italy. He was the son of a noble mother and father gentry. At seven's father died and the family had to take charge of their education. Early on he became interested in physics and despite the desire of his family to study a legal career, he managed to study science. He received a basic education and media humanist, but on reaching higher education, chose a scientific background.

In 1774 he was appointed professor of physics at the Royal School of Como. A year later, Volta made his first invention, an apparatus related to electricity. With two metal plates separated by a humid conductor, but united with an external circuit. It can thus for the first time, to produce electric current, perpetual electroform inventing a device is once charged, can transfer power to other objects, and static electricity generated. Between 1776 and 1778, was devoted to chemistry, discovering and isolating the methane gas. A year later, in 1779, he was appointed professor of the chair of experimental physics at the University of Pavia.

In 1780, a friend of Volta, Luigi Galvani observed that the contact of two different metals with the muscle of a frog originated the emergence of electric current. In 1794, Volta was interested in the idea and began experimenting with metals only, and concluded that the animal muscle tissue was not necessary to produce electricity.

 Alessandro Volta, "addressed a letter" to Sir Joseph Banks, the then leader of the Royal Society In March 20, 1800, in which he announced the discovery "of a voltaic pile". This letter was read before the Royal Society on June 26, 1800, after several reproductions of the invention done by the members of society, the invention was confirmed and given credit for it.

In September 1801, Volta traveled to Paris accepting an invitation of Emperor Napoleon Bonaparte, 4 to expose the features of his invention at the Institute of France. On 2 November the same year, the commission of distinguished scientists from the Academy of Sciences of the Institute of France responsible for assessing the invention of Volta issued its report asserting its validity. Impressed with Volta's battery, the emperor appointed him Count and Senator of the Kingdom of Lombardy, and awarded the highest distinction of the institution, the gold medal for scientific merit. The Emperor of Austria, meanwhile, selected on the post of director in the  section of philosophy at the University of Padua in 1815.

His works were published in five volumes in 1816, in Florence. The last years of life were spent at his estate in Camnago near Como, where he died on March 5, 1827.

The Geometry


The geometry is a branch of mathematics that deals with the study of the properties of figures in the plane or the space including: points, lines, planes, polytopes (including parallel, perpendicular, curves, surfaces, polygons, polyhedra, etc.).

It is the theoretical basis of descriptive geometry or technical drawing. It also gives substance to instruments like the compass, theodolite, the pantograph or global positioning system (especially when considered in combination with mathematical analysis and especially differential equations).

Geometry is one of the oldest sciences. Initially formed in a body of practical knowledge concerning lengths, areas and volúmenes.La Babylonian civilization was one of the first cultures to incorporate the study of geometry with the invention of the wheel the way to the study of the circle opened, which subsequently lead to the discovery of the number π (pi); They also developed the sexagesimal system, knowing that each year has 360 days, also implemented a formula for calculating the area of the trapezoid rectangular. In Ancient Egypt was highly developed, according to the texts of Herodotus, Strabo and Deodars, in third century. geometry configured as axiomatic and constructive treatment which established a rule to follow for many centuries Euclidean geometry described in The Elements.

Thursday, 12 February 2015

The Paramecium

The Paramecium

The Paramecium is a kind of completely ciliated protists. The term "eyelashes" have the paramecium with some other individual learning together that counts is traditionally one of the ciliates
Paramecium only lives in fresh water.

 They come in waters such as Pools, ponds, lakes, rivers, but also in puddles before. Thus, they are an important part of the ecosystem "freshwater". Paramecium are a common ciliates. Paramecium forms unlike many other unicellular no cysts as resting stages.

There are different types of paramecium, Paramecium caudatum, for example, Paramecium bursaria, Paramecium putrinum or trichium and others. Paramecium has their elastic skin, which hardly allows variation, a fixed slipper-shaped appearance. You using from 0.05 to 0.32 mm long. The largest species is one of the "giants" among the protozoa, as they are already seen in a drop of water to the naked eye as small white dots.

The Distillation Process


Separation of a mixture by distillation

The distillation allows to separate the components of a solution by exploiting their different volatility (volatility is defined as the tendency of a substance to evaporate: the liquid low boiling point have a high volatility).

It 'a separation technique is widely used in chemistry laboratories that at an industrial level and is often used to separate two immiscible liquids having different boiling temperatures. For example you can separate the components of the mixture water-ethanol. The liquors like brandy, whiskey and brandy spirits are called just because you get through distillation processes.
With the technique of distillation is also possible to separate the solvent from the solution of a solute or to fractionate systems normally gaseous state after being liquefied. An example is the separation of nitrogen and oxygen after liquefaction of air.

Types of distillation

Simple distillation

Separation of a mixture by simple distillation
The simple distillation, also called distillation at ordinary pressure, is a technique used in chemistry laboratories to separate the solvent from the solution of a solute.
Can also be used to separate miscible liquids with boiling points which differ by at least 25 ° C. The

Fractional distillation

Separation of a mixture by fractional distillation
The fractional distillation is used to separate the components of the solutions formed by miscible liquids ottennendo very high degrees of purity.
The equipment used is the same as the simple distillation, but with the addition of a rectification column which is inserted between the distillation flask and the refrigerant pipe (condenser).

Steam distillation

Separation by distillation of steam
The distillation in steam current exploits the phenomenon according to which the temperaura boiling of a mixture consisting of two immiscible liquids is lower than the boiling temperature of the most volatile component. For example temperature the boiling point of benzene is 85 ° C (P = 1atm) and the water is 100 ° C; instead the mixture boils at about 66 ° C, the lowest temperature of the most volatile component (benzene).

Wednesday, 11 February 2015

Argon Gas


Argon is a naturally occurring element with the element symbol Ar and atomic number 18. In the periodic table it is having an atomic mass of 39.948 u in the 8th main group. The William Ramsay in 1895 discovered chemical element is not radioactive and is located at room temperature in a gaseous state.

Characteristics:                argon (argon gas.)


Name:                               Argon
Symbol:                            Ar
Rank:                                 18
Group:                               noble gas group
Period:                               3
Block:                                p-block
Series:                               noble gases
Appearance:                    colorless
Discoverer:                      William Ramsay
Date of Discovery:       1895

Atomic Properties

Atomic mass:                39.948 u
Atomic radius:               ??? pm
Covalent radius:            106 pm
Van der Waals radius: 188 pm
Electron configuration: [Ne] 3s2 3p6
Ionization energy:           1520.8 kJ / mol

Physical Properties

State of matter:                gas
Density:                             ???
Crystal structure:            cubic
Magnetism:                      diamagnetic
Molar volume:                 22.56 • 10-6 m3 / mol
Mohs hardness:                /
Melting point:                -189 ° C
Boiling point:                -186 ° C
Heat of fusion                1.18 kJ / mol
Heat of vaporization:   6.52 kJ / mol
Thermal conductivity: 0.017 W
Electronegativity:          unknown



Friction, also referred to as friction, is the inhibition of a movement occurring between contacting solid bodies or particles. We distinguish between external friction between contacting interfaces of solids and internal friction between adjacent particles in the deformation of fluids and solids. In physical models frictional forces are often neglected when they are relatively small and / or quantitatively elusive. With regard to the energy loss occurring in the friction (their conversion into heat with an increase in entropy) is referred to as the dissipation, particularly in the case of kinetic energy, but also in general terms for non-mechanical processes.

Instead of "friction force" and the term is used frictional resistance. With the scientific study of friction processes dealt tribology (friction teaching).

Types of friction

External friction

External friction is also called solid friction, because it occurs between the contact surfaces of the contacting solids. It is divided into static friction and kinetic friction, both of which are designated in honor of the physicist Charles Augustin de Coulomb as Coulomb friction. You do not always segregate on. You can also or alternately occur; For example, the stick-slip effect is a periodic transition between static and dynamic friction. On the application-related terms are rolling friction, boring friction and rope friction.

The friction force FR increases with normal force FN, often approximately linear and independent of the size of the contact surface (see Amontonssche laws):

F _ {\ mathrm R} <= \ mu \ cdot F _ {\ mathrm N}.

The friction coefficients μ are dependent on the nature of the surfaces. The coefficient of adhesion is generally greater than that for sliding. Its value is determined experimentally. The inequality comes from the fact that a frictional force can never encounter.


In many cases, adhesion between contacting bodies is desirable. Without friction of everyday life would not work. Furniture would not stay in place, parked vehicles on the road (the wheels blocked) could be propelled solely by the wind. You could not set foot "fixed" on the ground, all driven wheels would "spin", so do not allow traction. In industrial applications, a technically generated pressure between the contact surfaces is used except for the most acting weight force, for example by means of tensioned springs in a friction clutch.

Stick is a state of rest, so that neither wear nor energy losses occur. It is a combination of form fit on a small scale by roughness as structural variation 3rd to 5th order, would be destroyed in motion, and molecular adhesion Retail by molecular attraction forces, ie adhesion.

Sliding friction

Sliding friction occurs at the contact surfaces between bodies that move relative to each other. For some material combinations creep occurs, so that the friction force opposing the Amontonsschen law is a function of speed. The sliding friction is usually lower than the static friction force with the same normal force.

Tuesday, 10 February 2015

Structure Of An Eye


The eye is a wonderful structure capable of generating the sense that the more we relate to the environment. Basically it is a kind of highly sophisticated camera so the aspect of vision as the ability to track an object with complex movements. Or objective lens of the camera is constituted by a set of tissues: cornea, lens, vitreous and aqueous humor. The diaphragm is located at the pupil center of the iris. The photographic film is represented by the retina.


The front part of the eye is a transparent dome, on which the contact lens is placed and Lasik is practiced.


The transparent membrane that lines the front of the balloon excluding the cornea. Within it are tiny glands that produce tears and mucus that help lubricate and disinfect the eyeball.


 The lens is precisely behind the iris, and its function is to achieve accurate focusing, which is known as accommodation. The shape of the lens is altered by a muscle which changes its curvature to focus on nearby objects and distant objects. When it loses its transparency, speaking of cataract.


 Behind the cornea is the iris: circular portion of pigmented tissue that gives color to the eye. The pupil, a circular is in the middle of the iris opening is enlarged and reduced to control the quantity of light entering the eye.


 The sclera (or eyes) is the white fibrous outer layer that covers the eyeball. Its function is to protect the sensitive structures of the eye.


 The choroid is the layer of blood vessels and lies between the retina and the sclera. It provides oxygen and nutrients to the retina. RETINA: The retina is a thin coat of multiple cell layers that is in the back of the eye. It is a membrane, light-harvesting antenna true. It functions as a screen on which the cornea and lens focus images. The macula, in the center of the retina, is the region that gives the vision of detail, allowing reading and color vision. There are two types of photoreceptor cells in the retina, cones and sticks, they transform images into nerve impulses sent to the brain. The cones require a relatively bright light (of day) for operation, but can detect many shades and nuances of color. By contrast, the rods require very low light (night), they allow viewing without colors, in black blue background.


 Is the fluid that fills the anterior part of the globe, between the cornea and iris. This is renewed permanently and drains into the bloodstream.


 The vitreous is the transparent mass occupying the space between the lens and the retina. It consists of a gelatinous substance that maintains the shape of the eyeball.

The Education System In The Russia

The education system in the Russian Federation is a set of interacting structures, which include:

1. Continuity of educational programs at different levels and focus, federal state educational standards and federal government requirements.

Educational program determines the content of a certain level of education and orientation. In the Russian Federation implements educational programs, which are divided into:

General education (basic and advanced);

Professional (basic and advanced).

The basic general education program include:

Early childhood education;
Primary education;
General education;
Secondary (complete) general education.
The main professional programs include:

Initial vocational education;
Secondary vocational education;

Higher professional education (bachelor's degree programs, training programs and graduate programs);
Postgraduate education.
Taking into account the needs and abilities of the individual educational programs being developed in the following forms:

in an educational institution - in the form of full-time, part-time (evening), correspondence;
in the form of family education;


A combination of different forms of education.

Lists of professions and occupations, the preparation of which a part-time (evening), part-time and in the form of external studies are not permitted in the competence of the Russian Federation established by the authorized Government of the Russian Federation, federal executive body (see. Resolution of the Government of the Russian Federation on primary, secondary and higher vocational education).

The use of distance learning technologies is the responsibility of the educational institution.

2. The network of educational institutions and scientific organizations implementing educational programs at different levels and focus, federal state educational standards and federal government requirements.

Educational institution is carrying out the educational process, that is, implementing one or more educational programs and (or) provide for the maintenance and education of students and pupils.

Educational institutions can be public (federal or under the jurisdiction of the Russian Federation), municipalities, non-governmental (private, public institutions and religious organizations (associations)).

An educational institution is a legal entity.

Monday, 9 February 2015

An Electrode


An electrode is an electron conductor together with a counter electrode with a medium located between two electrodes interacts. Electrodes are serene of electrical conductors, frequently a metal or graphite. They are used to connect non-electron-conducting regions with cables and find this example application in electrochemical cells, as a tool (eg. As in resistance spot welding) and possibly material dispenser during arc welding, as terminals and electro-optical elements in electron tubes. About the electrical function beyond electrode material may be deposited or consumed, or there may be physical processes taking place in the electrode as the anode of an X-ray tube.

 Electrodes in the gas or vacuum or insulator
 Depending on the type of the medium surrounding the electrode leads to different forms of interaction:

 If the medium is an insulator, an electric field is established between the electrodes. This pattern is called condenser. however, silent electric discharge.

 If the medium is a vacuum or a gas, so an electric field between the electrodes is built up as in the case of the insulator. However, electrons from one electrode (cathode) move to another when the exit from the cathode is made possible, eg. As by field emission or thermal emission or the Thermionic emission (→ electron tube, x-ray tube, thermionic cathode).

 If the medium is a gas, the atoms or molecules of the gas are partially ionized, so that a plasma is formed. In plasma, the ions move next to the electrons in the electric field (→ gas discharge lamp).

 Also, the spark plug electrodes, welding electrodes in arc welding and the electrodes inside the nozzle for plasma cutting fall into this category. The welding electrodes generate an arc welding with the material to be welded. In the heat of the arc both melt and the electrode is used as filler material, so that the materials are joined.



Electromagnetic transformers are static devices that starting from an alternating voltage connected to its input, other than the previous gain in the transformer output voltage varying alternating. And allow to provide an adequate tension to the receiver characteristics. They are also essential for transporting electricity over long distances at high voltages, with minimal losses and moderate conductive sections.

Consist essentially of a closed magnetic circuit on which two windings, so that both windings are crossed by the same magnetic flux are wound. The magnetic circuit is constituted (for industrial frequency of 50 Hz) of steel sheets stacked little thickness, to prevent eddy currents.

Winding where the input current is connected is called the primary, and the winding where the payload is connected, is called secondary. The alternating current flowing through the primary winding magnetizing the core alternately. And the secondary winding is traversed by a variable magnetic flux in an approximately sinusoidal flux variation and this engenders by Lenz's law, an alternating voltage in said winding.


The effective value of the electromotive force in the windings of the transformer is determined by the following formulas:

U1 = 4.44 BM A f n1

U2 = 4.44 BM A f n2


U1 = voltage at the primary winding (volts)

U2 = voltage in the secondary winding (volts)

BM = maximum value of the flux density in the core (Tesla). (In magnetic iron core transformer usually has a maximum value of 1.4 Tesla)

f = frequency of the alternating current (Hz)

n1 = number of turns of the primary winding (dimensionless)

n2 = number of turns of the secondary winding (dimensionless)

A = cross sectional area of the magnetic core (m2)

If the primary and secondary are traversed by the same maximal induction BM & A section of the core remains constant, then;

U1 / U2 = n1 / n2

This ratio is called transformation ratio, and indicates the relationship between input and output voltage, when the transformer is idling, or unloaded, in the secondary.

Saturday, 7 February 2015

Magnetic Flux


In physics, in particular in the magnetism, the magnetic flux is the magnetic flux through a surface, a scalar that depends on the angle of incidence of the field lines, the value of the magnetic permeability and the area of the surface itself. Is often referred to in the formulas with the Greek letter \ Phi_B, and the SI unit is the Wb. It is a quantity that appears in many areas of electromagnetism, for example, the change of magnetic flux through the surface bounded by a closed electrical circuit causes the appearance of an electromotive force in the circuit (Faraday's law).

it is possible to determine for each of these component B_ \ perp of the magnetic field vector B perpendicular to the surface at the position of the card in question. It is therefore B_ \ perp = B \ cos \ alpha, where \ alpha indicates the angle between \ B and the surface normal. In general, this component varies for each point of the surface.



"Entrepreneur" is a word that began to be used more than ten years and contained a large number of qualities. Being an entrepreneur is beyond or may not have their own business (made or planned), is a way of being, feeling, living and course work.

The employee-entrepreneur (intrapreneur) is in reality an entrepreneur: he searched frequently occupy a leadership position. It can be judged climber; but he's just ambitious and responds to an inner need to grow. You want to decide, do, teach, produce, get. He is enthusiastic and awake each day plagued by dreams materialize.

This type of partner in a company makes a fine contribution in their field of work because it assumes as its own and works to improve the environment with ideas and energy, since it is generally automotiva with relative ease.

Having the project, resources and planning, is only the beginning of a company, but are nothing without him who he conceived and give life. Images can be the same, people who carry out make the difference.

And as the opportunity arises, he will be a willing employee to dump their energy in some way, will surely be the other.

Your boss will feel no need to ask endeavor because it is advanced in ideas and innovations, often arrive early or leave late, and holidays generates new contributions to implement them to return.

Sometimes these characters are lost by not letting them create and believe which can work in the company own-like. Perhaps jealousy, competition or fear of being overtaken. Because it is in constant motion: he wants to learn, improve, innovate.

This kind of talent is gerenciable in a very different way. They are very emotional people, and as such react by emotion. But they feel that they are respected and paid even from recognition. They are much more resistant to adverse conditions or crises in companies employees because their motivation lies within them.

But for this very reason, rely more on themselves and know able to get another job. Dependent and feel them, which is not random or circumstantial.

We all know someone with these characteristics. They write their stories in books or are told by enthusiastic biographers. They appear in our lives from time to time to tell us: "Come on, wake up, you'll do if you really want!".

Some are well and is easy resources to develop themselves. In other sleep this entrepreneur one day, from within, will tell you that you can do better. And there are those who do not. Although nothing is impossible for humans, and therefore one can be proposed if so ever, this is not the only way to proceed.

It's just a way of being. Because they are the entertainers and spectators, and both parts are essential for there to show.

What it is undeniable is that the show offered by these "actors" of life do we continue believing in human strength, even when we thought we had lost all hope. Because to succeed need only one thing: to themselves !!

Friday, 6 February 2015

The Electrical Insulator


Electrical insulation is a material property that consists of the block of electric current, because the resistivity is very high. It is thus the opposite of electrical conduction. Electrical insulation is determined by an electrical voltage to bring about the object of examination by the one pole with a part (side) of this object (possibly a gas or a liquid) and connecting the other pole with a different part (side) of the same object. The electric current in this resistance measurement (or impedance measurement) is running must be negligible to speak of an electrical insulator.

Insulating materials are, for example,

 Plastic, in particular PVC, and XLPE, in wire and cables. Many carpets have been through the use of plastics, a good insulator. Tools such as screwdrivers and pliers have insulating plastic handles.

 Glass insulators on pylons, but also in lamps and screens

 Air in all aboveground transportation of electricity, but also in the variable capacitor in the older radios

 Oil on high voltage electrical equipment such as transformers and switchgear
 SF6, sulfur hexafluoride in electrical switchgear at high voltage or medium voltage

 Ceramics, especially porcelain fuses, insulators for electric fences, overhead lines of train, tram, trolleybus and telephone lines (abroad), in all heating appliances, such as toasters, coffee machines, fittings for halogen lamps, soldering etc.

 Bakelite, especially in the older equipment and installation material, but it is still applied in 2007
 Epoxy, in particular for printed circuit boards in electronic equipment

 Rubber, this is sometimes brands are the static charge of a person standing on rubber soles.
 Pres Spaan, this is a hard-pressed sheet of pure cellulose which is used in oil-in electrical installations in order to isolate very high voltages

 Paper or cellulose is also widely used in electrical installations.

Study At Malaysia


The study visa allows entry into Malaysia, for a short stay (90 days. - Type C) or long-term (91 to 365 days. - Type D) for foreigners intending to attend university to study or vocational training at institutes recognized or qualified, or the stranger who is expected to perform cultural activities and ricerca.Documenti required for STUDIO Registration to Italian Universities

Seen to be requested only after confirmation that he was admitted to the entrance exams, according to the provisions issued by the Ministry of Education

 1. application form to download an entry visa from the embassy of belonging where the guest arrives;

 2 recent passport-size photograph

 3. passport validity expiring for at least three months after visa;

 4. demonstration of the availability in Italy of livelihoods, equivalent to not less than € 417.30 per month duration of the academic year. This availability may be demonstrated by:

 • exhibition of means personal or family

 • financial guarantees provided by institutions and bodies of Italians established credit, by local governments, or by foreign institutions and organizations deemed reliable by the Italian diplomatic

 5. statement about the availability of suitable accommodation in Italy.

 Documents required for study Scholarships

 1. application form to download an entry visa from the embassy of belonging where the guest arrives;

 2 recent passport-size photograph

 3. passport validity expiring for at least three months after visa;

 4. documentation evidencing ownership of a scholarship granted by the Italian government, foundations or cultural institutions of renown, from international organizations, foreign governments and universities. Where the amount of the scholarship should need any further additions to reach the required amount of livelihoods, the economic availability can also be proven by demonstrating the availability of means of support in relation to the stay in Italy, for an amount not less than as defined in Table A attached to the Ministry of Interior Directive of 1.3.2000 (click here).

 5. Declaration of the visa applicant about the availability of suitable accommodation in Italy, as well as the sum needed for repatriation, which may also possibly with the performance of a return air ticket

 6. insurance coverage for medical care and hospitalization, demonstrated by:

 • Consular Declaration confirming the right to health care, in the presence of specific agreements between Italy and the country of the applicant;


 • foreign insurance policy or underwritten with Italian bodies or companies that will not result in limitations or exceptions to the tariffs set for urgent hospitalization.

Wednesday, 4 February 2015



Trigonometry (from the greek Trigonon (τρίγωνον, triangle) and Metron (μέτρον, measure): resolution of the triangle) is the part of mathematics that studies triangles starting from their corners. The main task of trigonometry, as well as reveals the etymology of the name, is to calculate the measures that characterize the elements of a triangle (the sides, corners, medians, etc.) starting from other measures already known (at least three, of which at least a length), by means of special functions. 

This task is referred to as the resolution of the triangle. You can also make use of trigonometric calculations in solving problems related to more complex geometric shapes, such as polygons or solid geometrical figures, and in many other branches of mathematics.

Trigonometric functions (the most important of which are the sine and cosine), introduced in this area, are also used independently from the geometry, appearing in other fields of mathematics and its applications, for example in connection with the function exponential or with vector operations.

For many centuries, trigonometry had his progress almost exclusively the work of great astronomers and geographers. In fact, the foundation of this science is due to Hipparchus and Ptolemy, both astronomers and geographers that most mathematicians. Significant contributions were made to this science by the Arabs, from the French Gersonides and later by Copernicus and Tycho Brahe, aims to describe and predict ever more precisely the celestial phenomena, also for a more accurate and convenient calculation of longitudes and latitudes.

The Optical Mirror

The Optical Mirror

Telescopes and other sophisticated tools are used mirrors to aluminizing front, ie where the metal layer is applied by the reflective side of the glass. This eliminates the double reflections and increases to 90-95% the proportion of reflected light (mirror new), but at the same time requires attention in handling the delicate object. Sometimes it is used the silver but more often the aluminum, which better reflects at shorter wavelengths, which are applied in vacuum chambers.

 Often also is deposited a protective layer over the reflective to prevent oxidation and corrosion. The coating needs to be redone periodically to maintain high performance, for this astronomical possibly have laboratories aluminizing. The reflectivity of a mirror is measured with the reflectometer, and is a function of the wavelength used and the metal. Sometimes we talk about it with mirrors hot or cold. The cold mirror reflects visible light but is transparent to infrared light, while the hot mirror does exactly the opposite, reflecting the infrared rays. In the halogen-type dichroic cold mirror reflector reflects visible light in a useful beam, while the infrared rays unnecessary through the reflector and are dispersed on the back of the lamp.

For particular scientific applications, for example in lasers, dielectric mirrors are often used, in which on the glass or more often other materials, is deposited a layer of dielectric material. by appropriately selecting the material and its thickness, can predetermine reflected light spectrum and reflectivity. The best mirrors of this type come to reflect the 99,999% of the incident light (in a limited range of wavelengths).

Tuesday, 3 February 2015

Study At Sweden


If you are going to study at a Swedish educational institution for more than 3 months, you must  have to apply for a residence permit for studies. During Rises studying for three months, you should apply for a visa.

You must show that you have money for your support throughout your scheduled study time, ie the corresponding 7 300 SEK / month for 10 months per year. For example, by submitting a certificate from the bank, you confirm that you have such financial means.
What is required for a residence permit application must be complete?

1. Completed application (a special form No. 104031 or 105031 in duplicate). The forms must be completed in English or Swedish.

2. Foreign Passport and copy of the ID page of passport (two copies).

3. Admission decision (+ copy).

4. Purchase fee (note that those who received a scholarship from the Swedish Institute or another
Swedish organization for studies in Sweden, is exempt from the fee).

5. Comprehensive sickness insurance cover in Sweden if you will be studying for less than one year at university / college.

Characteristics And Properties of Fluorine


Fluorine chemical element of atomic number 9, atomic weight 19.00 (he knows only one stable isotope, 199F). At room temperature is presented as a pale yellow gas, capable of liquefying only at very low temperature (-188 ° C at normal pressure). It is part of the group of the halogens, which constitutes the first member; is the most electronegative element, it shows a remarkable chemical reactivity and in fact is combined, directly or indirectly, with all elements (except with helium, argon and the neo) forming compounds, some of which are in turn equipped with easy to retain full activity, while others are exceptionally inert and stable. Many metals are attacked by the f., While some others form protective surface layers that prevent the progress of the attack to the underlying layers; so, as the lead reacts vigorously cold, aluminum, iron, chromium, nickel passivano for formation of stable protective veils cold; copper and gold are almost not at all attached.

The fluorination is the operation with which are introduced one or more atoms of f. in an organic compound. Several methods are: the most used consists in replacing the atoms of f. to atoms of other halogens already present in the molecule, and as agents for this operation using the tri- and antimony pentafluoride, hydrogen fluoride, fluoride, mercury or potassium. Other methods, of more limited application, are those of the electrolysis of a solution of hydrofluoric acid of the organic compound to be fluorinated and that of diazotization of an amine followed by decomposition of the diazonium salt to form the fluoride (method but of course only applies to aromatic compounds). Today the fluorination is widely used in the chemical industry, because the compounds that are obtained typically have exceptional properties of chemical and thermal stability.

The term fluorination is also used to indicate the coating of the outer surfaces of the lenses of optical instruments with an extremely thin layer of magnesium fluoride or cryolite, which allows to reduce 1-3% passive reflections, which amounted to about 4-7% of the transmitted light.

The Laws Of Electricity


We know that the potential difference ΔV from the generator starts moving electric charges in a circuit giving raise to an electric current. At constant applied potential difference, the current i that passes in a circuit depends on the characteristics of the conductive material that is used. Each conductor actually manifests a certain resistance to the passage of the current, due to collisions between the electrons in motion inside the conductor and the atoms of the impurities present in the circuit.

In mathematical terms, is defined as the resistance R of a conductor the ratio of the potential difference ΔV applied and the intensity of the current, ie R = ΔV / i. Since the current i appears in the denominator we have that in a conductor with high resistance R circulates a small current i, vice versa, a conductor with a small resistance R is characterized by the high currents. We can say that the resistance R measures the degree of opposition they meet the electrons to move up the potential difference ΔV. The unit of resistance is the ohm (Ω symbol, capital omega): 1 Ω = 1 V / 1 A.

In general, as the potential difference ΔV increases also the current i but there are various possible relationships between i and ΔV depending on the conductor that we take into consideration.
So if we measure with a voltmeter and the potential difference ΔV with an ammeter, the current i discover that in a metal the relationship R = ΔV / i is constant. In metallic conductors the resistance does not depend on the potential difference ΔV that we apply to the conductor. What determines then the resistance in a metallic conductor? The answer is given by the second law of Ohm. The resistance R in a conductor depends upon the material it is made of the wire, its length from its the section A. More precisely, we will have that R = ρ L / A, ie, the resistance is directly proportional to the length l of the wire and inversely proportional to the area of the section. The proportionality constant ρ (symbol that corresponds to the Greek letter ro) depends on the type of metal that we take into consideration and goes under the name of resistivity.
Resistivity small mean small resistance, ie good ability to conduct electricity. Since ρ = R • A / l, the unit of measurement of the resistivity in the International System is the ohm per meter (Ω • m).

Monday, 2 February 2015

Law Of Conservation Of Mass

law of conservation of mass

In 1748 formulated MW Lomonosov (1711-1765), the law of conservation of mass. The same law was AL Lavoisier (1743-1794), when he the reaction of metals with air (oxygen) investigated with the aid of the balance. The main merit of that research was the introduction of the scale in chemical works.

First chemical constitution

In a reaction, the mass of the substances concerned remains unchanged. The sum of the masses of the reaction products is thus equal to the sum of the masses of starting materials.

Mass of the starting materials = mass of the resulting materials

In 1756, Mikhail Lomonosov repeated this experiment Boyle and came to the conclusion that the phlogiston theory could not be true. Before Lomonosov opened the fed molten glass vessel, he placed a lighted candle in front of the opening. The candle flame was drawn at the moment of the opening in the vessel. Upon heating of lead in the sealed vessel was thus a part of the air "disappeared". The reaction product of the lead was now heavier than the lead before the experiment. Lomonosov wrote in his diary. "Today I conducted an experiment in hermetically sealed glass vessels, to see if the mass of a metal is larger under the mere action of heat The experiments of which I append a 13-page report, showed that the famous Robert Boyle was misled, because without access of air from outside the mass of burnt metal remained unchanged. ... It is the air particles that combine with the metals when heated, and this in turn limes ". The "limes" today would be described as metal oxides.

The Diamond

the diamonds\

Diamond is the cubic modification of carbon and as a naturally occurring solid mineral from the mineral class of elements. Diamond usually forms octahedral crystals, often with curved surfaces and streaky. Other forms observed are the tetrahedron, dodecahedron and the cube. The crystals are transparent, colorless or colored by impurities (eg., Nitrogen) or crystal lattice defects green, yellow, brown and rarely, orange, blue, pink, red or gray to black.

Diamond is the hardest natural substance. In the Moths hardness scale, he has the hardness of 10. His abrasive hardness Roswell (also absolute hardness) is 140 times greater than that of corundum. The hardness of the diamond is, however, different in different crystallographic directions (anisotropy). This makes it possible to grind diamond. In the diamond powder used for this purpose, the crystals are in any orientation before (statistical isotropy) so always worked the hardest of them on the body to be ground.

Diamond is optically isotropic with high refraction and high dispersion. He shows fluorescence and phosphorescence and is turboelectric. It has the highest thermal conductivity of all known minerals.