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December 01, 2016
  • In the 2 stroke engine it consists of one cycle with one rotation
  • In the 4 stroke engine it consists of one cycle with two rotations.
  • The inlet and the exhaust valves of the 4 stroke engine are replaced by 3 ports in a 2 stroke engine.
  • In 2 stroke engine the lubrication oil must be mixed with the petrol
  • In case of 4 stroke engine the lubrication and the fueling must take place separately
  • In the 2 stroke engine due to the presence of the lubrication oil, some of the lubrication oil must be combusted during the time of heat addition. Hence there is more friction and loss of work in 2 Engine
  • The power available in the 2 stroke engine is only 70% of the calculated power
  • In 4 stroke engine the power available is 90% of the calculated power
  • In 2 stroke engine the transfer port and the exhaust port are opened at the same time. Hence some fresh air fuel mixture will be escaped out of the engine cylinder, due to which there is loss of fuel.
  • For single cylinder engine the size of the flywheel is bigger than the 4 stroke engine.
  • Due to the above reason the 2 stroke engine on the roads are replaced by the 4 stroke engine
  • The overall efficiency of a 4 stroke engine is much higher than that of a 2 stroke engine.

Difference in between the petrol engine and diesel engine
  • The temperature at the end of the compression is less for the petrol engine.
  • Thus a spark plug is needed for the compression. In case of the diesel engine the temperature at the end of the compression is above the self-ignition temperature of the fuel.
  • Hence the fuel ignited is allowed to enter the cylinder due to the high temperature.
  • No spark plug is required for the diesel engine.

  • For the separate entry of the fuel after the compression stroke, a nozzle is provided for the diesel engines.
  • In case of the petrol engine they do not have the nozzle.
  • In petrol engine the air and the fuel, are mix inside a carburetor before entering the engine cylinder. In diesel engine there is no mixing of air and fuel before suction stroke. Hence diesel engine does not have a carburetor.
  • Heat addition must take place at the constant volume for petrol engine. It takes place at the constant pressure for diesel engine
  • For the same compression ratio, the efficiency of a petrol engine is higher than that of the diesel engine. This is theoretical.
  • In an actual practice the compression ratio of a diesel engine is 1.5 times to 2 times more than that of a petrol engine.
  • Hence the diesel engine efficiency is much higher.
  • Under some conditions the air fuel ratio for the petrol engine must be 16 and for the diesel engine case the ratio of the air fuel mixture must be 25 to 35.
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December 01, 2016
Technically, mechanical engineering is the application of the principles and problem-solving techniques of engineering from design to manufacturing to the marketplace for any object. Mechanical engineers analyze their work using the principles of motion, energy, and force — ensuring that designs function safely, efficiently, and reliably, all at a competitive cost.
Mechanical engineers make a difference. That’s because mechanical engineering careers center on creating technologies to meet human needs. Virtually every product or service in modern life has probably been touched in some way by a mechanical engineer to help humankind.
This includes solving today’s problems and creating future solutions in health care, energy, transportation, world hunger, space exploration, climate change, and more.
Being ingrained in many challenges and innovations across many fields means a mechanical engineering education is versatile. To meet this broad demand, mechanical engineers may design a component, a machine, a system, or a process.  This ranges from the macro to the micro, from the largest systems like cars and satellites to the smallest components like sensors and switches. Anything that needs to be manufactured — indeed, anything with moving parts — needs the expertise of a mechanical engineer.  
What do mechanical engineers do?
Mechanical engineering combines creativity, knowledge and analytical tools to complete the difficult task of shaping an idea into reality.
This transformation happens at the personal scale, affecting human lives on a level we can reach out and touch like robotic prostheses. It happens on the local scale, affecting people in community-level spaces, like with agile interconnected microgrids. And it happens on bigger scales, like with advanced power systems, through engineering that operates nationwide or across the globe.
Mechanical engineers have an enormous range of opportunity and their education mirrors this breadth of subjects. Students concentrate on one area while strengthening analytical and problem-solving skills applicable to any engineering situation.
Disciplines within mechanical engineering include but are not limited to:
·         Acoustics
·         Aerospace
·         Automation
·         Automotive
·         Autonomous Systems
·         Biotechnology
·         Composites
·         Computer Aided Design (CAD)
·         Control Systems
·         Cyber security
·         Design
·         Energy
·         Ergonomics
·         Human health
·         Manufacturing and additive manufacturing
·         Mechanics
·         Nanotechnology
·         Production planning
·         Robotics
·         Structural analysis
Technology itself has also shaped how mechanical engineers work and the suite of tools has grown quite powerful in recent decades. Computer-aided engineering (CAE) is an umbrella term that covers everything from typical CAD techniques to computer-aided manufacturing to computer-aided engineering, involving finite element analysis (FEA) and computational fluid dynamics (CFD). These tools and others have further broadened the horizons of mechanical engineering.
What careers are there in mechanical engineering?
Society depends on mechanical engineering. The need for this expertise is great in so many fields, and as such, there is no real limit for the freshly minted mechanical engineer. Jobs are always in demand, particularly in the automotive, aerospace, electronics, biotechnology, and energy industries.
Here are a handful of mechanical engineering fields.
In statics, research focuses on how forces are transmitted to and throughout a structure. Once a system is in motion, mechanical engineers look at dynamics, or what velocities, accelerations and resulting forces come into play.Kinematics then examines how a mechanism behaves as it moves through its range of motion.
Materials science delves into determining the best materials for different applications. A part of that is materials strength — testing support loads, stiffness, brittleness and other properties — which is essential for many construction, automobile, and medical materials.
How energy gets converted into useful power is the heart of thermodynamics, as well as determining what energy is lost in the process. One specific kind of energy, heat transfer, is crucial in many applications and requires gathering and analyzing temperature data and distributions.
Fluid mechanics, which also has a variety of applications, looks at many properties including pressure drops from fluid flow and aerodynamic drag forces.
Manufacturing is an important step in mechanical engineering. Within the field, researchers investigate the best processes to make manufacturing more efficient. Laboratory methods focus on improving how to measure both thermal and mechanical engineering products and processes. Likewise, machine design develops equipment-scale processes while electrical engineering focuses on circuitry. All this equipment produces vibrations, another field of mechanical engineering, in which researchers study how to predict and control vibrations.   
Engineering economics makes mechanical designs relevant and usable in the real world by estimating manufacturing and life cycle costs of materials, designs, and other engineered products.
What skills do mechanical engineers need?
The essence of engineering is problem solving. With this at its core, mechanical engineering also requires applied creativity — a hands on understanding of the work involved — along with strong interpersonal skills like networking, leadership, and conflict management. Creating a product is only part of the equation; knowing how to work with people, ideas, data, and economics fully makes a mechanical engineer.
What tasks do mechanical engineers do?
Careers in mechanical engineering call for a variety of tasks.
·         Conceptual design
·         Analysis
·         Presentations and report writing
·         Multidisciplinary teamwork
·         Concurrent engineering
·         Benchmarking the competition
·         Project management
·         Prototyping
·         Testing
·         Measurements
·         Data Interpretation
·         Developmental design
·         Research
·         Analysis (FEA and CFD)
·         Working with suppliers
·         Sales
·         Consulting
·         Customer service
How much do mechanical engineers earn?
Like careers in many other engineering fields, mechanical engineers are well paid. Compared to other fields, mechanical engineers earn well above average throughout each stage of their careers. According to salary.com, the median starting salary for a Mechanical Engineer I in the United States is just under $63,000, with the top ten percent earning close to $75,000.
The future of mechanical engineering
Breakthroughs in materials and analytical tools have opened new frontiers for mechanical engineers. Nanotechnology, biotechnology, composites, computational fluid dynamics (CFD), and acoustical engineering have all expanded the mechanical engineering toolbox.

Nanotechnology allows for the engineering of materials on the smallest of scales. With the ability to design and manufacture down to the elemental level, the possibilities for objects grows immensely. Composites are another area where the manipulation of materials allows for new manufacturing opportunities. By combining materials with different characteristics in innovative ways, the best of each material can be employed and new solutions found. CFD gives mechanical engineers the opportunity to study complex fluid flows analyzed with algorithms. This allows for the modeling of situations that would previously have been impossible. Acoustical engineering examines vibration and sound, providing the opportunity to reduce noise in devices and increase efficiency in everything from biotechnology to architecture.
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November 26, 2016
Internet Download Manager (IDM) is one of the best resource to download things from the internet, faster and safer. It boosts the download speed by up to 5 times. If your computer were accidentally shutdown, the internet connection lost or any other problem while downloading by which your download would not be able to continue, then IDM provides you the ability to resume those downloads easily. If you are trying to find other download managers out there on the internet then here is a list of 10 Alternatives of Internet Download Manager.

Alternatives of IDM

1. JDownloader

JDownloader is an open-source free software for downloading things from the internet, it has a huge list of developers who work on JDownloader and make the downloads as faster as they should be. Same like Internet Download Manager you can start, pause, resume, and stop downloads. You can also schedule your downloads and can save bandwidth if you uses a limited internet device. It makes the downloads up to 10% faster and saves your precious time.
Jdownloader logo
2. Download Accelerator Plus (DAP)
DAP gives you the fast acceleration on each download with complete set of download tools. DAP have made it even easier to download things faster, smoother and safer. Explore all the features of DAP, download the latest version of DAP by clicking the button below and see why over 293 million users are using DAP as there internet downloads management.

3. Internet Download Accelerator

Internet Download AccelaratorYet another Download management software for your PC to enhance the download speed on each download noticeably. The acceleration is achieved by splitting the file into more parts and download them on the same time gradually in a few minutes. You can also resume your broken downloads, start, pause and stop the downloads on one click action. You can also target the URL to download things from a webpage. If you like to use Internet Download Accelerator click the button below:

4. Orbit Downloader

Orbit DownloaderOrbit Downloader is really a great download manager, it aims to download video/music/files from the most popular social media sites like Myspace, YouTube, Imeem, Pandora, Rapidshare, etc. It makes the general downloading even easier, faster and safer to all. Some of the great key features by Orbit Downloader:
Key Features
  • Download files easily from a webpage
  • Download music, video and streaming media from social media sites
  • Fast acceleration to download
  • Supports RapidShare download
  • Supports all major browsers
  • Supports Metalink to target a download
  • Supports HTTP, HTTPS, MMS, FTP, RTSP and RTMP protocols
  • Proxy server configuration is available
  • Support download pause and resume
  • General download management

5. FreeRapid Downloader

FreeRapid Downloader is available for windows, Linux, MacOS, etc. Stop bearing the default lazy downloading and try something unique. It’s a Java based downloader and aims to download things from Rapidshare, Facebook, Youtube, and other file-sharing services. FreeRapid Downloader lets you add specific links to download by simply adding the link in this software’s add URL option.

6. FlashGet Downloader

FlashGet Best DownloaderFlashGet is the best download manager to download the stuff from the internet into your computer faster, safer and clean from malware, spyware, etc. You can call anti-virus cleaner after completing the installations of FlashGet Downlaoder to clean bugs that will exist in the computer. It boosts the downloading speed by up to 6-10 times.

7. Go!Zilla Downloader

Go!Zilla improves your internet downloading speed on full tilt, Go!Zilla download manager and download accelerator software is for Windows. Here are some key features by Go!Zilla Software:
Key Features
  • You can see what files are in progress and what files have finished
  • Get a file from several servers at once for faster download speeds
  • Resume previous downloads file if your internet had lost connections, crashes, reboots, last time
  • Works within your web browser to make downloading simple
  • Quickly grab batches of files from a web site, ftp server, or even a podcast
  • Includes download technology used by millions of people all over the world to download Billions of files
  • Supports HTTP, FTP, BitTorrent, HTTPS, FTPS protocols; and all major web browsers
  • Works with any Internet connection: modem, Wireless, DSL, Cable or anything else.

8. Download Accelerator Manager (DAM)

Download Accelerator Manager (DAM) enable us to download not only internet files but also web media files from such most popular sites like YouTube, Vimeo, DailyMotion, etc at maximum speed. DAM is one of the best downloading software like IDM to grab videos and audio musics from a webpage. It works in all major web browsers. DAM is blazing fast, clean and easy to use.
To download DAM click the button right over here:

9. GetRight Download Manager

With GetRight Download Manager schedules, resumes and accelerates your downloads. You don’t need to worry about your web connection on failing in the middle of the download. GetRight has been a leader and an innovator among other download manager softwares.

10. Mipony Download Manager

Mipony is completely free software and designed to download files from free hosting webpages like Fileserve, Rapidshare, Hotfiles etc. With Mipony download manager, you don’t need to worry about managing your downloads after all Mipony takes care of your every download.
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November 15, 2016
periodic table elements

 Americium could save your life.
Thanks to high school, we’ve all got a pretty good idea about what’s on the periodic table.
But whether you’re looking at something common like calcium, iron, and carbon, or something more obscure like krypton and antimony, how well do you know their functions? Could you name just one practical application for vanadium or ruthenium? 
Lucky for us, Keith Enevoldsen from elements.wlonk.com has come up with this awesome periodic table that gives you at least one example for every single element (except for those weird superheavy elements that don’t actually exist in nature).
There’s thulium for laser eye surgery, cerium for lighter flints, and krypton for flashlights. You’ve got strontium for fireworks, and xenon for high-intensity lamps inside lighthouses. 
Oh and that very patriotic element, americium? We use that in smoke detectors. 
First unveiled in 1945 during the Manhattan Project, americium is produced by bombarding plutonium with neutrons in a nuclear reactor.
The resulting americium is radioactive, and while the tiny amounts of americium dioxide (AmO2) used in smoke detector produces alpha radiation to sniff out a fire, it will deliver approximately zero radiation to anyone living nearby.
I kinda want to tell you all about rubidium and how we use it in the world’s most accurate time-keeping devices, and how niobium can help make trains levitate,but you should just check out the periodic table for yourself. 
We’ve included a sneak-peak below, but for the real interactive experience, click here to try it out.
periodic table newYou can also download the PDF if you’ve got a class to teach, or maybe you just want to be great and put it on your bathroom door.
And if this whole exercise has made you realise just how rusty you’ve become with your science basics, check out AsapSCIENCE’s Periodic Table Song below.
We’d like to see a better way of memorising the periodic table - it's even got the four brand new elements that earned a permanent spot in the seventh row back in January (which unfortunately have no cool uses outside of atomic research).
Check it out:
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November 06, 2016
Q Carbon
It is a well-known fact that diamond is the hardest material on the planet. However, diamond lost its status of the hardest substance when scientists at the North Carolina State University discovered a new, harder-than-diamond form of carbon.The research team found a new phase of carbon, called the Q-carbon.

The new phase of carbon is quite different from graphite and diamond. Q-Carbon shows some unique and quite unexpected properties like ferromagnetic nature. Another unusual feature of this phase of carbon is that it begins to glow in the presence of energy. See more images from various experiments below:







The research has been published in the Journal of Applied Physics. The Q-phase of carbon was created by focusing a laser beam on amorphous carbon for 200-nanoseconds. The temperature of the amorphous carbon sample rose quickly and was cooled down by the process of quenching to create Q-Carbon.
This recent discovery will be a massive breakthrough in the domain of structures and materials. The new hardest material on the planet might be used for the fabrication of prosthetic structures, improvement of the equipment used for deep drilling, as well as developing new, brighter screens for the smartphones and televisions.
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