Intresting Science Facts that NEVER learnt at School.

There is nothing in the world more amazing than the wonders of science and nature unfolding before us. The technology and the biological life we are surrounded by everyday are a proof to the fact that science is far more fascinating than any magical or fantasy tale we’ve encountered. So, here are some such incredible science facts that will take you on an irresistible trip to a world of wonder.

1. Ferrofluid – a suspension of magnetic nano-particles that form patterns of spikes in the presence of magnetic field.

 

 Ferrofluid is a colloid made of magnetic nanoparticles suspended in a carrier fluid such as organic solvent or water. Ever single one of these particles are coated with a surfactant so that they won’t clump together into a lump and stay fluid. The formation of spikes is due to normal-field instability, an effect that causes the fluid to assume a shape that minimizes the total energy of the system. It was first invented as a liquid fuel that could be drawn toward pump inlet in gravity-free environment. Ferrofluid also has many other applications. It is used as a liquid seal in electronic devices such as hard disks offering negligible friction and acting as an efficient barrier for debris.

2. A man defies gravity by doing a loop the loop on foot. 

          

 During circular motion, there are two main forces acting on the body – centripetal, the force that pulls you towards the center, and centrifugal, the force that pulls you away from the center. Many people have made use of this simple law of physics to defy gravity by going on a loop on skateboards and motorcycles. Damian Walter, a stuntman and gymnast, did it on foot. To achieve this he had to accelerate to a velocity of 13.84 km per hour or 8.65 miles per hour at the highest point and keep his head and shoulders at the center of the loop.

3. You can relight a candle by holding a flame into the smoke that rises after you blow it out.

 

 

 When you light a candle, the wax evaporates into the air and undergoes combustion producing light in return. When you blow out the candle the smoke that rises up contains the wax vapor that hasn’t yet undergone combustion. So when you hold a flame into that smoke it lights up burning all the way down its trail to the wick, relighting the candle.

4. This is what happens when you heat a surface to very high temperatures and pour water drops. It’s called Leidenfrost effect. 

                           

 
 If you cook, you probably already observed this. When you heat a pan on high for some time and then pour water drops they become mercurial. Instead of evaporating the water drops just move around on the pan like mercury. This happens because when the water hits the pan its outer surface evaporates so fast that it creates a layer of vapor below the water drop insulating it and stopping it from coming into direct contact with the pan. So, instead of boiling the water just rolls around. If you do the experiment on ridged surface like shown above, the water drops would even move upwards.

5. Miura Fold is a rigid origami technique that can be used to fold rigid materials into flat parallelograms. It is used to fold large solar panels in Japanese satellites before launch which can then be spread out when in space. 

   
                       

 The folding patterns of this origami form a regularly repeated pattern of parallelograms. Each adjacent parallelogram is a mirror image of the one before and after it. When folded this way, any flat material can be packed into a compact shape which can be pulled open and closed shut by moving the opposite corners. This technique when used in folding the solar arrays reduces the number of motors required for unfolding in space, reducing the weight of the satellite.

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Role of Electronic Gates in Building Circuits.

Over the 50 years or so that electronics circuit designers have been working on semiconductor-based logic circuits, many designs have been developed for creating logic gates. Because each approach to designing logic circuits results in an entire family of logic circuits for the various types of gates (NOT, AND, OR, NAND, NOR, XOR, and XNOR), the different designs are often referred to as design families.
Here are the most popular:

                           

• RTL: Resistor-Transistor Logic, which uses resistors and bipolar transistors.
• DTL: Diode-Transistor Logic, which is similar to RTL but adds a diode to each input circuit.
• TTL: Transistor-Transistor Logic which uses two transistors, one configured to work as a switch and the other configured to work as an amplifier. The switching transistor is used in the input circuits, and the amplifier transistor is used in the output circuits. The amplifier allows the gate’s output to be connected to a larger number of inputs than RTL or DTL circuits.
  In a TTL circuit, the switching transistors are actually special transistors that have two or more emitters. Each input is connected to one of these emitters so that the separate inputs all control the same collector-emitter circuit. The switching transistor’s base is connected to the Vcc supply voltage, and the collector is connected to the base of the amplifying transistor.
  
  
  Although you can build TTL circuits by using individual transistors, ICs with TTL circuits are readily available. The most popular types of TTL ICs are designated by numbers in the form 74nn. In all, a few hundred types of 7400-series integrated circuits are available. Many of them provide advanced logic circuits that you aren’t likely to use for home electronics projects.

  Number	Description
  7400	Quad two-input NAND gate (four NAND gates)
  7402	Quad two-input NOR gate (four NOR gates)
  7404	Hex inverter (six NOT gates)
  7408	Quad two-input AND gate (four AND gates)
  7432	Quad two-input OR gate (four OR gates)
  7486	Quad two-input XOR gate (four XOR gates)

  
  
  
  
  
  
  
  CMOS: Complementary Metal-Oxide Semiconductor Logic, which refers to logic circuits built with a special type of transistor called a MOSFET. MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor.
  
  
   NOTE: The physics of how a MOSFET differs from a standard bipolar transistor aren’t all that important unless you want to become an IC designer. What is important is that MOSFETs use much less power, can switch states much faster, and are significantly smaller than bipolar transistors. These differences make MOSFETs ideal for modern integrated circuits, which often require millions of transistors on a single chip.
  
  
  Apart from drawing less power and operating faster than TTL circuits, CMOS circuits work much like TTL circuits. In fact, CMOS chips are designed to be interchangeable with comparable TTL chips.
  CMOS logic chips have a four-digit part number that begins with the number 4 and are often called 4000-series chips. As with the 7400 series of TTL logic chips, several hundred types of 4000-series chips are available.

  Number	Description
  4001	Quad two-input NOR gate (four NOR gates)
  4009	Hex inverter (six NOT gates)
  4011	Quad two-input NAND gate (four NAND gates)
  4030	Quad two-input XOR gate (four XOR gates)
  4071	Quad two-input OR gate (four OR gates)
  4077	Quad two-input XNOR gate (four XNOR gates)
  4081	Quad two-input AND gate (four AND gates)

  
  
  CMOS logic circuits are very sensitive to static electricity. Make sure that you discharge yourself properly by touching a grounded metal surface before you touch a CMOS chip. For maximum protection, wear an antistatic wrist band.. 

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Now ARTIFICIAL INTELLIGENCE can predict your heart failure.

Artificial Intelligence is a branch in computer science in which we train computer to behave like humans. The term was coined in 1956 by John McCarthy at the Massachusetts Institute of Technology.
           Currently, no computers exhibit full artificial intelligence (that is, are able to simulate human behavior). The greatest advances have occurred in the field of games playing. The best computer chess programs are now capable of beating humans. In May, 1997, an IBM super-computer called Deep Blue defeated world chess champion Gary Kasparov in a chess match.

An artificial intelligence system has accurately predicted when patients with heart conditions will die, according to new results published in the journal Radiology.
The study was conducted by a team of scientists at the London Institute of Medical Services, who trained the software to analyze blood tests and intricate 3D models of beating hearts in order to detect signs of failure. The AI was assigned 256 patients diagnosed with pulmonary hypertension, a type of high blood pressure which impacts the lungs and can cause dizziness, fainting, and shortness of breath.
By tracking the movement of 30,000 different points on a patient’s heart, it was able to construct an intricate 3D scan of the organ. Combining these models with patient health records going back eight years, the system could learn which abnormalities signaled a patient’s approaching death, making predictions about five years into the future.
The AI predicted with 80 percent accuracy which patients would die in the next year. The average doctor’s accuracy is about 60 percent.
   
                        
Treatments for pulmonary hypertension include drugs, lung transplants, and targeted medicines, but the choice of treatment depends on the prognosis. As a result, an AI with such high accuracy can help physicians better treat patients.
“The AI really allows you to tailor the individual treatment,” Dr. Declan O’Regan, one on the researchers, told BBC News“So it takes the results of dozens of different tests including imaging, to predict what’s going to happen to individual patients very accurately. So we can tailor getting absolutely the right intensive treatment to those who will benefit the most.”
AI software is becoming increasingly adept at diagnosing diseases. In July, Google announced success in diagnosing ye diesease using machine learning software. A month earlier, researchers from Harvard Medical School (HMS) and Beth Israel Deaconess Medical Center (BIDMC) demonstrated a system that could detect Breast Cancer with 92% accuracy.  When combined with the analysis of pathologists, that rate shot up to 99.5 percent.

  For any queries related to artificial intelligence comment us below.

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Info. About File Extensions.

What is File Extension?

A file extension, sometimes called a file suffix or a filename extension, is the character or group of characters after the period that make up an entire file name.

The file extension helps an operating system, like Windows, determine which program on your computer the file is associated with.

For example, the file myfile.docx ends in docx, a file extension that might be associated with Microsoft Word on your computer.

When you attempt to open this file, Windows sees that the file ends in a DOCX extension, which it already knows should be opened with the Microsoft Word program.

File extensions also often indicate the file type, or file format, of the file... but not always. Any file's extensions can be renamed but that won't convert the file to another format or change anything about the file other than this portion of its name.

File Extensions vs File Formats

File extensions and file formats are often spoken about interchangeably - I do it here on my site, too. In reality, however, the file extension is just whatever characters are after the period while the file format speaks to the way in which the data in the file is organized - in other words, what sort of file it is.

For example, in the file name mydata.csv, the file extension is csv, indicating that this is a CSV file. I could easily rename that file to mydata.mp3 but that wouldn't mean that I could play the file on my smartphone.

The file itself is still rows of text (a CSV file), not a compressed musical recording (an MP3 file).

Changing the Program That Opens a File

As I already mentioned, file extensions help Windows, or whatever operating system you're using, determine which program is to open those types of file, if any, when those files are opened directly, usually with a double-tap or double-click.

Many file extensions, especially those used by common image, audio, and video formats, are usually compatible with more than one program you have installed.

However, in most operating systems, only one program can be set to open when the file is accessed directly. In most versions of Windows, this can be changed via settings found in Control Panel.


Converting Files From One Format to Another

Like I mentioned above in File Extensions vs File Formats, simply renaming a file to change its extension won't change what type of file it is, even though it might appear as though that happened when Windows shows the icon associated with the new file extension.

To truly change the type of file, it has to be converted using a program that supports both types of files or a dedicated tool designed to convert the file from the format its in to the format you want it to be in.

For example, let's say you have an SRF image file from your Sony digital camera but a website you want to upload the image to only allows JPEG files.

You could rename the file from something.srf to something.jpeg but the file wouldn't really be different, it would only have a different name.

To convert the file from SRF to JPEG, you would find a program that fully supports both so you could open the SRF file and then export or save the image as JPG. In this example, Adobe Photoshop is a perfect example of an image manipulation program that could do this job.

If you don't have access to a program that natively supports both formats you need, many dedicated file conversion programs are available.

Executable File Extensions

Some file extensions are classified as executable, meaning that when clicked, they don't just open for viewing or playing. Instead, they actually do something all by themselves, like install a program, start a process, run a script, etc.

Because files with these extensions are just a single step away from doing lots of things to your computer, you have to be very careful when you receive a file like this from a source you don't trust.

If you have any queries left about this topic you can comment us below.

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What is Virtual Private Network (VPN) ?

What is a Virtual Private Network (VPN)?

A VPN or Virtual Private Network is a network connection that enables you to create a secure connection over the public Internet to private networks at a remote location. With a VPN, all network traffic (data, voice, and video) goes through a secure virtual tunnel between the host device (client) and the VPN provider’s servers, and is encrypted. VPN technology uses a combination of features such as encryption, tunneling protocols, data encapsulation, and certified connections to provide you with a secure connection to private networks and to protect your identity.
VPN connections technically give you all the benefits of a Local Area Network (LAN), which is similar to that found in many offices but without requiring a hard-wired connection.
Early VPNs were often set up to give individual employees secure remote access to their company networks, hence the name “virtual private network”. By connecting to the company’s network, an individual employee can access all the company’s resources and services as if the employee were inside the company.
Since then, VPNs have evolved to provide the same level of secure communication between any device on the internet. Today, using VPN is increasingly popular among consumers as a means to protect their privacy online, secure their browsing sessions, and get unrestricted access to content or websites that are otherwise blocked or censored.

Types of VPNs

VPNs differ by architecture, purpose of usage, and accessibility. Two basic types of accessibility are site-to-site VPN and remote access VPN.
Figure 1. Site-to-Site VPN and Remote Access VPN connecting to a Corporate Network
Site-to-site VPNs are used in the corporate environment. A site-to-site VPN ensures the safe encrypted connection of two or more local area networks (LANs) of the same company or of different companies. It means two geographically separated offices are virtually bridged together into a single LAN and users can access data throughout this network.
Remote Access VPNs connect an individual computer to a private network. This type of VPN can be divided again into two groups:

• Corporate VPNs – Corporate VPNs allow business travelers and telecommuters to connect to their company networks and remotely access resources and services on the networks. When a user connects his/her device to the company’s VPN, the VPN thinks that the user’s computer is on the same local network as the VPN.
• Personal VPNs – Personal VPNs provide consumers with the same private and secure connection as the corporate VPNs. However, personal VPNs are not used to connect to private networks to access private resources.

Personal VPN services are especially useful when connecting to a public WiFi network. It is estimated that nearly 90% of public WiFi networks are not secured. By using a VPN service, all your internet communications will be encrypted, making it almost impossible for hackers and snoopers to read and steal your private information.
There are many personal VPN service providers available for consumers to choose from, with many offering VPN services to consumers for free or for a low monthly subscription fee. These services also make it easy and quick for you to install and use a VPN on practically any platform, including mobile and tablet devices.

Benefits of Masking Your IP Address

A VPN masks your IP address, giving you much greater privacy for your online activities. Unshielded, this IP address – the unique address for each device on the internet – can be misused to reveal your identity, location, ISP, and even the specifics of your online activity.
When you use a VPN, your IP address is masked so you can surf the web anonymously. Thus, no one can find out where you connect from or what you do online.
Moreover, by exchanging your IP address with the VPN server’s IP address, you can virtually connect from a geographic location that is different from where you are physically located.
For instance, you may be sitting inside a coffee shop in Dubai, but by connecting to a remote VPN server, you can appear to connect to the Internet from another location (i.e. San Francisco or New York) which hosts the VPN server you’re connecting to.
This enables you to bypass regional internet restrictions and get access to content (i.e. YouTube, Facebook) or internet services (i.e. Skype, Gmail, Viber) that are otherwise restricted or censored in the location you are staying in.

VPN Hardware and Software

VPN is a client-server technology that is made up of hardware and software components on both the client (user) side and the server side. As VPNs have progressed from a corporate tool into today’s personal VPN, the installation requires no additional hardware on the user side other than the computer or device for accessing the internet.

Client (your computer)

• The hardware is the personal computer, smart phone or tablet
• The software is the VPN client app running on your device

VPN Server

• The hardware are server computers and traffic routers
• The software controls the traffic routing and communication between the servers and the client (your computer).

VPN traffic flow

Both inbound and outbound traffic is routed through VPN servers. Depending on the traffic direction, the data is encrypted and decrypted either on the client’s computer or on the VPN server. For example, let’s assume you want to watch video on YouTube. You search for the video on YouTube and play it. Since this is outbound traffic, this data is encrypted on your computer by the VPN client.
Encrypted commands are sent to the closest VPN server, which then forwards the encrypted commands through the network of the servers to the gateway server, where the command is decrypted and sent through the public internet to YouTube.
As the video is played, since it is inbound traffic, the process is repeated in reverse. The video stream goes to the VPN server where it gets encrypted, sent to the closest client server, and forwarded to the client where it is decrypted and played in the client’s internet browser. You, as the user (client), get the IP address of the VPN gateway server so it is difficult to track down your real IP address and pinpoint your geographical location.

Security at the packet level

VPN security begins at the data packet level – the basic building block of online communication. Each data packet is encrypted, packaged in multiple envelopes, and treated as a certified letter. Taken together, these steps ensure data is secure even against deep data packet analysis and potential eavesdropping anywhere between the two connected computers.

Encryption

Full data encryption is a basic element in a VPN. With a VPN, all traffic between the two computers is encrypted and isolated in a secure tunnel, shutting out ISPs from eavesdropping and logging your web activity.
Encryption for devices connected to a VPN goes beyond just web browsing. It includes VOIP communication, Skype, emails – anything that uses an online connection. This gives you more comprehensive protection than a proxy server, which is limited to only shielding your web browsing activity.

Envelope Strategy

VPNs use various tunneling protocols to encapsulate data packets for secure transit. Tunneling protocols essentially place the individual data packets – open postcards with the names of the sender and recipient and the data payload – into new sealed envelopes marked with the IP address of the VPN. Each envelope contains and conceals the earlier message envelopes. In addition to the layered envelopes, the original message within is also encrypted.

Point-to-point Communication

When a VPN tunnel connection is opened up, it authenticates sender identity and the integrity of the sent messages. Similar to a registered letter providing point-to-point communication, it ensures that no unauthorized people can intercept the message and that data packets are not tampered with.

VPN Security Protocols

In the pursuit of creating a virtual private network, with its combination of tunneling, encryption, and data encapsulation, security experts have created three different families of VPNs, each with their own specific characteristics: IPsec, PPTP, and SSL. There is no “one-size-fits-all” list of specs for a VPN. Computer experts primarily divide them by technical details and consumers distinguish them by ease of use and portability.

IPsec Family

• Internet Protocol Security (IPsec) – With IPsec, all application traffic is secured across an IP network. IPsec protocol provides session authentication and data packet encryption between the two connected parties. It is primarily designed for protecting the data flows between networks (network-to-network) and the individual worker’s remote connection to the company network.
• Layer 2 Tunneling Protocol (L2TP) – L2TP is used to make a tunnel between two L2TP control connection endpoints. Because it does not provide any encryption or authentication features by itself, it is usually paired with an encryption protocol such as IPsec.

PPTP family

Point Tunneling Protocol (PPTP) uses a point-to-point protocol to make a direct connection between two nodes. It was the first VPN protocol to be supported by Microsoft Dial-up Networking and has been bundled into all releases of Microsoft Windows since Windows 95. The Microsoft connection has been an important part of PPTP’s acceptance in the market.
While the PPTP protocol has the advantage of a pre-installed client base on Windows platforms, analysis by cryptography experts have identified several security issues such as its vulnerability to password guessing attacks.

SSL family

• Secure Sockets Layer (SSL) and Transport Layer Security (TLS) – SSL is commonly used to secure online shopping as a user’s web browsers can almost transparently switch to SSL without requiring additional configuration or extra software. SSL was the industry standard before it evolved into Transport Layer Security. The SSL protocol works at the application level independent of the specific network. The “sockets” part of the term refers to the sockets method of passing data back and forth between a client and a server or program layers in the same computer.
  
  SSL uses the public-and-private key encryption system from RSA, which also includes the use of a digital certificate. TLS and SSL are an integral part of most Web browsers (clients) and Web servers.
• Open VPN – OpenVPN is an open source VPN based on the SSL protocol that is focused on organizations in the SME (Small and Medium Enterprise) and enterprise segment. It provides portability, ease of configuration, and compatibility with NAT (Network Address Translation) and dynamic addresses.

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Virus.

Computer Virus Information.

 

What is a computer virus?

Think of a biological virus – the kind that makes you sick. It’s persistently nasty, keeps you from functioning normally and often requires something powerful to get rid of it. A computer virus is very similar. Designed to relentlessly replicate, computer viruses infect your programs and files, alter the way your computer operates or stop it from working altogether. It’s estimated that the Conficker virus infected more than 10 million computers in 2009. Tens of thousands of computer viruses now operate over the Internet, and new computer viruses are discovered every day.

How does a computer virus find me?

Even if you’re careful you can pick up computer viruses through normal Web activities like:

• Sharing music, files or photos with other users
• Visiting an infected Web site
• Opening spam email or an email attachment
• Downloading free games, toolbars, media players and other system utilities
• Installing mainstream software applications without fully reading license agreements

What does a computer virus do?

Some computer viruses are programmed to harm your computer by damaging programs, deleting files, or reformatting the hard drive. Others simply replicate themselves or flood a network with traffic, making it impossible to perform any internet activity. Even less harmful computer viruses can significantly disrupt your system’s performance, sapping computer memory and causing frequent computer crashes.

What are the symptoms of a computer virus?

Your computer may be infected if you recognize any of these malware symptoms:

• Slow computer performance
• Erratic computer behavior
• Unexplained data loss
• Frequent computer crashes

Computer Virus Help: Arming yourself with the best computer virus protection?

When you arm yourself with information and resources, you’re wiser about computer security threats and less vulnerable to threat tactics. Take these steps to safeguard your PC with the best computer virus protection:

Make sure that you have the best security software products installed on your computer:

• Use antivirus protection and a firewall
• Get antispyware software
• Always keep your antivirus protection and antispyware software up-to-date
• Update your operating system regularly
• Increase your browser security settings
• Avoid questionable Web sites
• Only download software from sites you trust. Carefully evaluate free software and file-sharing applications before downloading them.

 Hope you like this post . You may post your suggestion and queries below in the comment box.

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Download Youtube Videos Without Software.

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