What is Chemosynthesis

Chemosynthesis is a process certain organisms use to produce energy, akin to photosynthesis, but without the utilization of sunlight. The energy comes from the oxidization (burning) of chemicals which seep up from the Earth's crust. The organisms that use chemosynthesis, all bacteria, manufacture carbohydrates and other organic molecules from the oxidization of sulfates or ammonia. The hydrogen they use comes from hydrogen sulfite, whereas the nitrogen comes from ammonia or nitrates. The organisms that use chemosynthesis are found around hydrothermal vents on the ocean floor. They are adapted to circumstances which would have been commonplace billion of years ago, leading some to call them descendants of the earliest life on Earth.

Organisms that use chemosynthesis are extremophiles, living in harsh conditions such as the absence of sunlight and a wide range of water temperatures, some approaching the boiling point. These organisms are known for living inside one another, engaging in symbiotic and parasitic relationships to maximize their chances of survival. Chemosynthetic microbes provide the foundation for larger communities of organisms which consume the microbes to survive. One interesting example is the tubeworm, filled with billions of chemosynthetic bacteria. The tubeworm starts life with a mouth and gut, which it uses to intake many bacteria. Its mouth then closes and it continues to survive by consuming food produced by its internal bacteria.

Chemosynthetic species are autotrophs, organisms capable of manufacturing organic matter directly from inorganic feedstock. Autotrophs of different types can produce energy either through photosynthesis or chemosynthesis. The gases that autotrophs use to create energy would be poisonous to most organisms. 

They use unusual enzymes capable of resisting high temperatures and pressures. Since these organisms live on the bottom of the ocean floor, they are subject to much pressure from the water above. Ecologies surrounding deep sea vents are extremely prosperous relative to those located further away from such chemical sources, which must survive solely on dead organic matter slowly descending from the waters above.

Chemosynthetic organisms have been viewed by the biotech industry as a means of converting toxic chemicals into harmless organic variants. If life exists on other planets or moons such as Mars or Titan, it has been postulated that they may use chemosynthesis.

What is the Difference Between 720p and 1080p HDTVs

High-definition television (HDTV) is available in both 720p and 1080p models. The difference between them boils down to resolution, with 1080p capable of displaying a higher native resolution than 720p sets. This doesn’t necessarily mean that in all instances a 1080p HDTV will display a better picture than a 720p set. We can thank multiple broadcast formats and the varying quality of electronic components used in HDTVs to complicate the issue just a bit.

First, the basics. Every HDTV has what’s referred to as a native resolution. This is the only resolution the television can display. Every broadcast it receives or digital format it displays (such as a DVD), must all display in the native format. To do this the HDTV converts any signal that differs from its native resolution to the native resolution. Lower resolutions are “upgraded” and higher resolutions are “downgraded.” This process is known as upconverting and downconverting. 

In the switch from standard definition broadcasts to high-definition broadcasts, there are competing formats. Some networks broadcast in 720p (1280 x 720) and others in 1080i (1920 x 1080). A 720p HDTV will be able to display 720p broadcasts natively. Displaying a signal without conversion results in an excellent picture. Once the TV has to convert a signal, the conversion process itself can degrade picture quality. Therefore a 720p broadcast might look better on a 720p TV than on a 1080p, if the processor chip in the 1080p HDTV is not up to snuff. 

Other networks broadcast in 1080i, which the 1080p HDTV can display natively. A 720p set will have to downconvert a 1080i signal before displaying it. Both HDTVs will also have to de-interlace the 1080i signal but this does not involve changing the resolution, only reordering frame display. An interlaced signal is designed to paint every other line on the display, then fill in the missing lines. Progressive scan TVs paint the screen sequentially, from top to bottom, reducing the flicker affect of interlaced signals.

So far it might sound like a wash. A 720p HDTV will display 720p broadcasts natively, and a 1080p will display 1080i broadcasts natively. The 1080p might be seen as having the advantage that it will also upconvert 720p signals to 1080p resolution, and if the internal processing chip is a good one, this should improve picture quality to lessen "stair stepping" and the "screen door affect" by packing more pixels into the image for an overall smoother quality. Meanwhile, the 720p set will have to downconvert 1080i broadcasts

But the real advantage of the 1080p is in watching HD DVD and Blu-ray discs. These digital discs are formatted in 1080p and studio movies on this media played on the 1080p HDTV are astounding. A 720p set that will accept a Blu-Ray signal must downconvert these formats to lesser resolutions, robbing the viewer of the true Blu-ray / HD DVD experience. The 1080p is also a preferable set for gamers who intend to connect a PC, XBox™ or PlayStation™. 

All else being equal, 720p HDTVs are less expensive than their higher resolution siblings. If you aren’t big on DVDs and don’t plan on buying a Blu-ray or HD DVD player, you might opt to save some money. For gamers or movie fanatics, consider the higher resolution set, but stick with a quality brand that will provide a solid upconverter for all of those 720p broadcasts you’ll be watching between movies. Also, be sure the 1080p HDTV provides 1080p inputs or ports. Accepting 1080p input (as from a Blu-Ray player) is a different function than upconverting broadcast signals, and some earlier models lacked the ability to accept 1080p signals.

What is a Dry Cell Battery

The dry cell battery is one of the most commonly used types of batteries. A, C, 9-volt, and watch batteries are dry cell batteries. Invented by Sakizou Yai in 1885, the dry cell battery was improved and patented by Dr. Carl Gassner, a German scientist in 1887. A dry cell battery is different from a wet cell battery because its electrolytes are contained in a low-moisture paste. A wet cell battery's electrolytes are contained in a liquid. Wet cell batteries are often used in cars because they are relatively cheap and easily recharged.

Dry cell batteries, regardless of their size, have the same components. At the center of each dry cell battery is a rod called a cathode, which is generally made of metal or graphite and is surrounded by an electrolyte paste. The cathode and electrolyte paste are wrapped in paper or cardboard. One or more of these cells are sealed into a metal cylinder called an anode, which is typically made of zinc or alkaline.

The anode in the dry cell battery has two or more terminals — one that is positive and one that is negative. When a load is connected to the battery's terminals, a chemical reaction occurs between the cathode and the paste in each cell to produce roughly 1.5 volts of electricity. A battery that has more than one cell will produce a higher overall voltage. After the load has been connected for a long time, the battery's chemicals can no longer react with each other and will therefore no longer produce a charge. 

Alkaline batteries are more popular than their older zinc counterparts because they corrode more slowly and thus hold their charge longer. A less commonly used type of dry cell battery uses silver for the cathode rod. Another type is the mercury cell, which uses mercury in the cathode and is often used to power calculators. Nickel/cadmium (NiCd), nickel metal hydride (NiMH), and lithium-ion (Li-Ion) dry cell batteries are rechargeable, making them popular for use in power-hungry digital cameras and portable electronics.

All batteries contain chemicals that are harmful if released into the environment, so all used dry cell batteries should be recycled properly. Many municipal recycling programs accept batteries. Consumers should also consider using rechargeable batteries because they can be reused many times and can also be recycled after they no longer hold a charge.

What Is 4G

4G, an acronym for fourth-generation wireless, is a type of technology that can be used with cellular phones, wireless computers, and other mobile devices. This technology give users faster access to the Internet than most previous third-generation (3G) networks can offer, and it also offers new user options such as the ability to access high-definition (HD) video, high-quality voice, and high-data-rate wireless channels via mobile devices. In 2009, the ITU Radiocommunication Sector (ITU-R) defined the standards for the successor to 3G: the new technology must provide peak speed for Internet communication at 100 megabits per second (Mbps) for high mobility users, which includes those in cars and trains, and 1 gigabit per second (Gbps) for low mobility users, such as pedestrians or those who are stationary while using their device. Like previous generation technologies, the newest version is not expected to be fully incorporated worldwide for several years.

New Services

The fourth-generation wireless technology provides a wide variety of services including the option to download, view, and upload high-definition (HD) videos, which could potentially change the way some companies do business; video conferences could become more common, for example. High-quality voice when using a cellular phone is another added benefit of 4G technology, as well as access to high-data-rate wireless channels. 4G is also known as "beyond 3G," since it provides a comprehensive and secure Internet Protocol (IP) solution. Users have access to high-quality streaming video and "anytime, anywhere" voice and data at a much higher speed than previous generations. The "anytime, anywhere" solution of 4G technology is also referred to as "MAGIC," which is an abbreviation for Mobile multimedia; Anytime/anywhere; Global mobility support; Integrated wireless solution; and Customized personal services.

Objectives

The 4G working group has defined several objectives of the fourth-generation wireless communication standard. This includes a high mobility rate of 100 Mbps between any two points in the world, seamless connectivity allowing users to enjoy global roaming across multiple networks, and support for using high-quality multimedia. Perhaps users will be willing to purchase the technology as it is said to be up to ten times faster than previous 3G options, with broadband accessibility in rural areas that previously lacked high-speed internet capabilities.

The fourth-generation will inter-operate with third generation systems and broadband broadcasting systems; it also intends to integrate fixed wireless access (FWA), wireless local area network (WLAN), wireless local loop (WLL) and personal area network (PAN), to provide fully IP-based wireless internet. When fully implemented, this technology could help create additional markets and opportunities for new and established telecommunication enterprises. A 4G network can potentially open the gates of video blogging on mobile phones when combined with cell phones that are equipped with advanced HD capabilities, or high-quality digital cameras.

Development

With a higher data rate and broader bandwidth capability, 4G technology focuses on providing seamless service across a multitude of wireless networks and systems. Some of the core technologies employed by fourth-generation wireless include Orthogonal Frequency Division Multiplexing (OFDM), Software-Defined Radio (SDR) receivers, Orthogonal Frequency Division Multiple Access (OFDMA) Universal Mobile Telecommunications System (UTMS), and multiple input/multiple output technologies (MIMO). Together, these technologies could ensure high rates of data transmissions for 4G users, though the availability may not be offered everywhere for several years.