Monday, June 21, 2010
Impact factor of journals
It is a measure of reflecting the average number of citations to article published in science, engineering, social science and technology. Those who are pursuing Ph.D.s and publishing journals should know about impact factor of the particular journals. This article mainly for those who wish to publish journals of some standard and impact factor.
Most of Universities are recommending their scholars to publish journals of high impact factor.
Most of the recent journals are paid journals which have no impact factor. They do even not reviewing the articles received and publishing it in their journals for sack of earning money.
What is impact factor?
It is a qualitative measure of any journals published. Based on the impact factor, we can judge the relative importance of journals. Impact factors are calculated yearly for those indexed in Thomson Reuters.
The formula used for IM is
A = the number of times articles published in 2008 and 2009 were cited by indexed journals during 2008
B = the total number of "citable items" published in 2008 and 2009. ("Citable items" are usually articles, reviews, proceedings, or notes; not editorials or Letters-to-the-Editor.)
impact factor = A/B
The 2009 impact factors are actually published in 2010; they cannot be calculated until all of the 2009 publications have been received by the indexing agency.
The Journal Citation Reports also includes the Five year impact factor. This factor varies from year to year. The impact factors of journals are available in excel format. The can be freely downloaded from scopus site.
Thursday, June 17, 2010
A Quick review of Solar Panel working
I would like to share this article "an instant solution to understand how solar panels work" which i received from Barbara Young.
What exactly is solar energy ?
Solar power is radiant energy that is produced by the sun. Daily the sun radiates, or sends out, an immense volume of energy. The sun radiates more energy in a second than people have used since the beginning of time!
The energy of the Sun derives from within the sun itself. Like other stars, the sun is really a big ball of gases––mostly hydrogen and helium atoms.
The hydrogen atoms in the sun’s core combine to form helium and generate energy in a process called nuclear fusion.
During nuclear fusion, the sun’s extremely high pressure and temperature cause hydrogen atoms to come apart and their nuclei (the central cores of the atoms) to fuse or combine. Four hydrogen nuclei fuse to become one helium atom. But the helium atom contains less mass than the four hydrogen atoms that fused. Some matter is lost during nuclear fusion. The lost matter is emitted into space as radiant energy.
It takes an incredible number of years for the energy in the sun’s core to make its way to the solar surface, after which somewhat over eight minutes to travel the 93 million miles to earth. The solar energy travels to the earth at a speed of 186,000 miles per second, the speed of sunshine.
Simply a small percentage of the power radiated by the sun into space strikes the earth, one part in two billion. Yet this volume of energy is enormous. Everyday enough energy strikes the united states to provide the nation’s energy needs for one and a half years!
Where does all of this energy go?
About 15 percent of the sun’s energy that hits the earth is reflected back to space. Another 30 percent is used to evaporate water, which, lifted in to the atmosphere, produces rainfall. Solar energy also is absorbed by plants, the land, and the oceans. The remaining could be employed to supply our energy needs.
Who invented solar technology ?
People have harnessed solar power for years and years. As early as the 7th century B.C., people used simple magnifying glasses to concentrate the light of the sun into beams so hot they would cause wood to catch fire. Over 100 years ago in France, a scientist used heat from a solar collector to make steam to drive a steam engine. In the beginning of this century, scientists and engineers began researching ways to use solar technology in earnest. One important development was obviously a remarkably efficient solar boiler introduced by Charles Greeley Abbott, an american astrophysicist, in 1936.
The solar water heater came into common use at this time in Florida, California, and the Southwest. The industry started in the early 1920s and was in full swing just before The second world war. This growth lasted prior to the mid-1950s when low-cost propane took over as primary fuel for heating American homes.
The public and world governments remained largely indifferent to the possibilities of solar power prior to the oil shortages of the1970s. Today, people use solar technology to heat buildings and water and to generate electricity.
How we use solar energy today ?
Solar energy is used in a number of different ways, of course. There are two very basic types of solar power:
* Solar thermal energy collects the sun's warmth through one of two means: in water or in an anti-freeze (glycol) mixture.
* Solar photovoltaic energy converts the sun's radiation to usable electricity.
Listed below are the five most practical and popular methods solar energy is used:
1. Small portable solar photovoltaic systems. We see these used everywhere, from calculators to solar garden tools. Portable units can be used for everything from RV appliances while single panel systems can be used traffic signs and remote monitoring stations.
2. Solar pool heating. Running water in direct circulation systems through a solar collector is a very practical way to heat water for your pool or spa.
3. Thermal glycol energy to heat water. In this method (indirect circulation), glycol is heated by sunshine and the heat is then transferred to water in a hot water tank. This method of collecting the sun's energy is more practical now than ever. In areas as far north as Edmonton, Alberta, solar thermal to heat water is economically sound. It can pay for itself in 3 years or less.
4. Integrating solar photovoltaic energy into your home or office power. In numerous parts on the planet, solar photovoltaics is an economically feasible method to supplement the power of your property. In Japan, photovoltaics are competitive with other kinds of power. In america alone, new incentive programs make this form of solar technology ever more viable in many states. A frequent and practical method of integrating solar energy into the power of your home or business is through the use of building integrated solar photovoltaics.
5. Large independent photovoltaic systems. For those who have enough sun power at your site, you may be able to go off grid. You may also integrate or hybridize your solar energy system with wind power or other forms of renewable energy to stay 'off the grid.'
How can Photovoltaic panels work ?
Silicon is mounted beneath non-reflective glass to create photovoltaic panels. These panels collect photons from the sun, converting them into DC electrical power. The power created then flows into an inverter. The inverter transforms the energy into basic voltage and AC electricity.
Solar cells are prepared with particular materials called semiconductors like silicon, which is presently the most generally used. When light hits the Photovoltaic cell, a particular share of it is absorbed inside the semiconductor material. This means that the energy of the absorbed light is given to the semiconductor.
The power unfastens the electrons, permitting them to run freely. Solar cells also have one or more electric fields that act to compel electrons unfastened by light absorption to flow in a specific direction. This flow of electrons is a current, and by introducing metal links on the top and bottom of the -Photovoltaic cell, the current can be drawn to use it externally.
What are the positives and negatives of solar energy ?
Solar Pro Arguments
- Heating our homes with oil or propane or using electricity from power plants running with oil and coal is a reason for climate change and climate disruption. Solar power, on the contrary, is clean and environmentally-friendly.
- Solar hot-water heaters require little maintenance, and their initial investment can be recovered in just a relatively limited time.
- Solar hot-water heaters can work in almost any climate, even in very cold ones. You just have to choose the best system for your climate: drainback, thermosyphon, batch-ICS, etc.
- Maintenance costs of solar powered systems are minimal and also the warranties large.
- Financial incentives (USA, Canada, European states…) can reduce the cost of the initial investment in solar technologies. The U.S. government, for example, offers tax credits for solar systems certified by by the SRCC (Solar Rating and Certification Corporation), which amount to 30 percent of the investment (2009-2016 period).
Solar Cons Arguments
- The first investment in Solar Hot water heaters or in Photovoltaic Electric Systems is higher than that required by conventional electric and gas heaters systems.
- The payback period of solar PV-electric systems is high, as well as those of solar space heating or solar cooling (only the solar hot water heating payback is short or relatively short).
- Solar water heating do not support a direct in conjunction with radiators (including baseboard ones).
- Some air conditioning (solar space heating and the solar cooling systems) are expensive, and rather untested technologies: solar air-con isn't, till now, a truly economical option.
- The efficiency of solar powered systems is rather influenced by sunlight resources. It's in colder climates, where heating or electricity needs are higher, that the efficiency is smaller.
About the Author - Barbara Young writes on motorhome solar battery charger in her personal hobby blog 12voltsolarpanels.net. Her efforts are focused entirely on helping people save energy using solar powered energy to lower CO2 emissions and energy dependency.
Tuesday, June 8, 2010
iPhone 4 with novel features
Apple has unveiled a novel i-phone with novel features. The so called 4 G technology has been a new boom to the phone era. As the taste of mobile phone user have been changing day by day, this is an another milestone in the phone era. The competition among introducing new phones have been a thrust in adding new features. According to Apple, the new phone is chemically strengthened and 30 times harder than plastic material and scratch proof.
The features can be listed here,
• 5 megapixel camera with LED flash
• A4 processor as the iPad
• Second microphone for noise cancelling
• 720p (30 frames per second) video recording with tap to focus
• 802.11n Wi-Fi
• Quad-band HSUPA (7.2Mbps down, 5.8Mbps up)
• "FaceTime" video calls (Wi-Fi only)
• 960 x 640 "Retina" display
• 3-axis gyro in addition to the accelerometer for PS3-style 6-axis motion control
• Seven hours 3G talk time, six hours 3G web browsing, 10 hours video playback
• 9.3mm thick
• iOS 4.0 with multitasking and folders
• iMovie app for $4.99
• iBooks app (free)
• Official Apple case for $29
• $199 for the 16GB and $299 for the 32GB model
• 8GB iPhone 3GS will be available for $99
This novel phone is available:
The iPhone 4 will be available in the US, UK, France, Germany and Japan on June 24, and in Australia, Austria, Belgium, Canada, Denmark, Finland, Hong Kong, Ireland, Italy, Luxembourg, Netherlands, Norway, New Zealand, Singapore, South Korea, Spain, Sweden and Switzerland by the end of July