Social media serve as the communications infrastructure for the Internet users and are intensifying the shift in power towards increasing civic engagement and sovereignty. Small interest communities make the most use of social media on the the Internet. Status updates, microblogs, social bookmarks, video sharing, photo commentaries and other recommendations stimulate niche markets, a large number of which are dotted all over the net.
More and more Germans are using the the Internet. On average, in 2010 every German aged 14 and over surfed the web for 100 minutes a day. Almost 50% of over-50s and fully 23% in the 70+ age cohort regularly spend time on the the Internet. The ability to be contacted anywhere in the world is taken just as much for granted as exchanging large volumes of data at low cost. The parameters for all active the Internet users are short communication channels, the rapid viral spread of information, the decentralized organization of collective mobilization, and a wide range of options to participate in many spheres of everyday life. The technical means for people to create digital content themselves are becoming increasingly user-friendly, meaning that professional firms are no longer the only ones to offer digital content. As consumers evolve into prosumers, growth in the amount of user-generated content is unstoppable and networking is becoming ever more closely knit to span the globe.
Not all digital content is of (economic) value, however. There is a greater danger of information being misinterpreted because it often appears out of context. Comprehension in pattern form, i.e. following and understanding topics, trends and discussions, is easier in specific communities in which people work selectively and collectively on information. The consequences of this growing network density and the flow of real-time information in constantly new contexts are also apparent in rising degrees of complexity, reduced scope for control and rapid rates of change for business and society.
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| 1. short communication channels | |
| 2. the rapid viral spread of information | |
| 3. the decentralized organization of collective mobilization | |
| 4. a wide range of options | |
| 5. user-generated content | |
| 6. growing network density |
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Complexity, collectively, density, selectively, discussion, specific, economic, closely, unstoppable, professional, user-friendly, digital, increasingly, organization, mobilization, communication, intensify, social, engagement, sovereignty.
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Liquid Hydrogen
Liquid hydrogen is the liquid state of the chemical element hydrogen. From its gaseous state, hydrogen is simultaneously pressurized and cooled below its critical point. Typically, it is used as hydrogen storage because of its lightweight, compact nature. It is commonly used for applications such as processes in the U.S. space shuttles. However, there are various disadvantages in liquid hydrogen.
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Leaks
Storing liquid hydrogen takes less space than when it is in its normal state. It should be confined in a pressurized and thermally insulated container. It is challenging to maintain a low temperature, even in thermally insulated containers. If the temperature is not kept below its critical point, the hydrogen will seep out. Its gradual evaporation rate is 1 percent per day. This may lead to mixture with other gases, possibly causing fires.
Accidents
Liquid hydrogen is dreaded for its intensive explosions. When ignited with other gases, a big explosion may occur. An invisible spark can trigger the ignition. Hydrogen flames are unnoticeable and it is difficult to stop the fire from spreading once it starts. You can only detect it from its odor.
Prevention in Buildings
To prevent accidents, you must ensure that the liquid hydrogen is stored in a pressurized and thermally insulated container. It should be kept in a safe place. If your building has liquid hydrogen stored, you should provide good ventilation. Free circulation of air prevents the hydrogen from accumulating. The roof of the building should be designed in a way that allows it to be carried away when an explosion happens. It should also have a special piping system, far from other pipes. A UV/IR flame detector is a hydrogen sensor that can be put in the building system.
Prevention in Automobiles
If you are dealing with equipment powered by liquid hydrogen, you must keep it from being ignited. You must eliminate all sources of sparks. This could come from electrical equipments, static electricity, fire, and hot objects. All safety measures should take place not only at your place, but also in fueling stations, and automobile manufacturing industries.
Liquid Hydrogen Uses
Liquid hydrogen is the liquid state of the gaseous element hydrogen. Its chemical symbol is LH2, the "L" standing for liquid. It is made and kept at exceptionally cold temperatures, and reaches its liquefied state at -423.17 degrees Fahrenheit. It is known as cryogenic liquid and has many uses, mainly in scientific fields of study.
History
Liquid hydrogen has been known and studied since the 19th century, when the Scottish chemist, James Dewar, first liquefied it. Previously, he invented a vacuum flask that enabled him to liquefy hydrogen by using a regenerative cooling system. The system cooled the gas by allowing it to expand and then pass through a heat exchanger that had in it more compressed gas. Paul Harteck and Karl Bonhoeffer expanded on Dewars knowledge and created parahydrogen in 1929. Parahydrogen is hydrogen that has protons aligned on poles opposite to each other.
Rocket Engines
Liquid hydrogen is most commonly known as a component of rocket engine combustibility. The presence of liquid hydrogen cools the nozzle and other elements of the combustion chamber that will be exposed to extreme heat. Upon becoming gaseous and mixing with an oxidizer such as liquid oxygen, the liquid hydrogen ignites and creates a powerful thrust that will enable large projectiles to leave Earths gravity. The great clouds of "smoke" that you see upon the launch of the space shuttle are actually liquid hydrogen returning to its natural state, boiling away into the atmosphere. NASA is the largest consumer of liquid hydrogen in the world.
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Fuel Cells
Liquid hydrogen, in fuel cells, powers hydrogen cars and buses. Buses that use liquid hydrogen have longer fuel ranges and capabilities than regular combustion engine vehicles that use petroleum products, according to Hydrogen Fuel Cars Now. The German car manufacturer BMW already has a hydrogen mini car that runs on a 12-cylinder engine. Hydrogen is absorbed back into the atmosphere, making it an alternative green fuel source.
Magnets
Liquid hydrogen helps cool superconductive magnets used in capturing scientific images, including the magnets that create images of the body that are captured by the MRI, or Magnetic Resonance Imaging. Liquid hydrogen is applied to magnets that would otherwise break with the amount of heat they generate in creating magnetic fields. These magnetic fields affect the hydrogen in the water contained in the body, and these will align with the magnetic field to help capture an image. Such magnetic fields are used in the study of extremely small subatomic particles and are of practical use in physics laboratories around the world.
