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Justin Bieber gets killed by Cartman's "friend" Season 14 episode 13
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Baby, Please Kill Me! Episode 1
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We can and will not be held responsible for any personal and/or property damage that may be caused by any technique used in this video. Do not atte...
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We can and will not be held responsible for any personal and/or property damage that may be caused by any technique used in this video. Do not attempt this if you do not know what you are doing. This was originally for a class project and so doesnt go into detail on safety.
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Membrane556 liked a video
(1 day ago)
We make potassium metal using a lesser known chemical approach of reduction with magnesium.
Warning: Making potassium is extremely dangerous. Full f...
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We make potassium metal using a lesser known chemical approach of reduction with magnesium.
Warning: Making potassium is extremely dangerous. Full fire safety protocols must be in place including protective clothing, goggles and face shields. Burning potassium cannot be extinguished by conventional means and water only serves to increase its danger. This experiment should only be performed by an experienced chemist in a fume hood.
In a flask place 2.4g of magnesium turnings or powder, 5g of potassium hydroxide, and 20 mL of tetahydronapthalene or paraffin/mineral oil. If using oil the boiling point should be greater than 200 degrees Celsius.
Fit a reflux condenser onto the flask and prevent air access by covering the top of the condenser with foil. Alternatively a bubbler or a punctured balloon may be used.
Heat the reaction to reflux or +200 degrees Celsius. Color change of the solvent may occur at this time.
Inject of 0.4 mL of a tertiary alcohol (t-butanol and t-amyl alcohol have been confirmed successful) through the top of the condenser.
Add in an additional 0.1mL of alcohol every 10 minutes for a total of 0.6 mL of additional alcohol (1.0 mL overall).
Continue to reflux until potassium is produced. If potassium goes dark, add an additional 0.1 mL of alcohol.
What's happening is the magnesium reacts with the potassium hydroxide to produce potassium metal, hydrogen gas and magnesium oxide. The alcohol catalyzes this reaction.
If you're using a high-density solvent where the potassium spheres float, then coalescence of the spheres into larger spheres should occur automatically. If they are not, then an additional 0.1 mL shot of alcohol may be necessary. If using a lower density solvent, then coalescence may be achieved using this video: http://www.youtube.com/watch?v=xzkajg...
The reaction is done when there is no more magnesium. Turn off the heating and allow to cool.
Dump the cooled products into toluene and retrieve the metallic potassium, washing with additional toluene.
Place the potassium into a clean vial with mineral oil for short term storage.
All apparatus must be rendered safe before water-washing by first adding isopropanol to all containers that handled potassium. Any potassium residues should start bubbling. Only when bubbling has ceased can the wastes be disposed of as organic waste and containers subsequently washed with water.
DO NOT use water washing before alcohol washing as metallic potassium residues will ignite.
Additional Notes:
Alcohol *may* be added entirely at the beginning of the reaction but reproducibility is an issue since a competing reaction of alcohol decomposition sometimes occurs. It is difficult to predict how all reagents and solvent grades will behave so it is recommended to first attempt the experiment with staggered addition as outlined here.
A special note about long term storage safety. Do not leave potassium in storage for too long. Potassium forms shock sensitive explosive coatings on prolonged storage even under mineral oil. It is recommended that potassium be used or destroyed within a few months. If long-term storage is required then sealing in a glass ampoule or storage in an inert atmosphere glove box is recommended. Further information about the dangers can be found at: http://pubs.acs.org/doi/pdf/10.1021/e...
Occasionally stirring the reaction (every 30-45 minutes) greatly improves reaction rate and yield. Remember to allow reaction to cool before removing the condenser.
The quality of magnesium is important for the reaction. Highly oxidized magnesium didn't work to produce potassium. Buying new magnesium, or grinding it off from a magnesium ingot is recommended. Alternatively, low quality magnesium maybe activated by placing it into the solvent first without the potassium hydroxide and adding 0.1mL of alcohol and boiling for several minutes. The alcohol helps to etch the surface and restore activity. Note, this method is not absolutely reliable.
There have been reports of sodium being made by this method but I have never been able to successfully make it.
Further reading at: http://www.sciencemadness.org/talk/vi...
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Membrane556 liked a video
(1 day ago)
Aerodynamic SmartBird flight model - Bird flight deciphered: http://www.festo.com/smartbird_en
Aerodynamisches Flugmodell SmartBird - Vogelflug ents...
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Aerodynamic SmartBird flight model - Bird flight deciphered: http://www.festo.com/smartbird_en
Aerodynamisches Flugmodell SmartBird - Vogelflug entschlüsselt: http://www.festo.com/smartbird_de
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SmartBird is an ultralight but powerful flight model with excellent aerodynamic qualities and extreme agility. With SmartBird, Festo has succeeded in deciphering the flight of birds - one of the oldest dreams of humankind.
This bionic technology-bearer, which is inspired by the herring gull, can start, fly and land autonomously -- with no additional drive mechanism. Its wings not only beat up and down, but also twist at specific angles. This is made possible by an active articulated torsional drive unit, which in combination with a complex control system attains an unprecedented level of efficiency in flight operation. Festo has thus succeeded for the first time in creating an energy-efficient technical adaptation of this model from nature.
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SmartBird ist ein ultraleichtes, aber leistungsstarkes Flugmodell mit einer hervorragenden Aerodynamik und maximaler Agilität. Mit SmartBird ist es Festo gelungen, einen der ältesten Menschheitsträume zu entschlüsseln: den Vogelflug.
Der von der Silbermöwe inspirierte, bionische Technologieträger kann von selbst starten, fliegen und landen - ohne zusätzlichen Antrieb. Seine Flügel schlagen dabei nicht nur auf und ab, sondern verdrehen sich gezielt. Dies geschieht durch einen aktiven Gelenktorsionsantrieb, der in Verbindung mit einer komplexen Regelung bisher unerreichte Wirkungsgrade im Flugbetrieb realisiert. Damit gelingt Festo erstmals eine energieeffiziente, technische Adaption des natürlichen Vorbilds.
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