| Thermo_Vacuum_Generators One of the worlds leading manufacturers of UHV components. On this web-site you will also find a lot of reference data on vacuum components (e.g. pumps, gauges, valves, flanges etc.) including their p |
| Ultra_High_Vacuum Describes what ultra high vacuum (UHV) is, why we need in it, how to get UHV. |
| Vacuum_Technology_and_Vacuum_Coating_Forum Discuss subjects about vacuum physics, vacuum and coating systems, evaporation coating and sputtering technology. |
| Vacuum_Technology_Guide Links to buyers guides, organizations, research, eZines and journals world-wide. |
| Vacuum_Technology_Lessons Lessons and practical exercises on Vacuum Technology. |
| Vacuüm_Specials,_The_Netherlands Specialised in the implementation, construction, manufacturing of components and subsystems and the realisation of complex projects on a turnkey basis regarding vacuum technology and cryogenic applica |
| What_is_vacuum? Nice web-site for beginners who want to know "what vacuum is"... |
| Foreign_Policy_In_Focus__Environment Issue papers on environmental matters that relate to U.S. foreign policy. |
| Greenleaf_Publishing Specialist publisher in the business and environment sector, including the journals Greener Management International and The Journal of Corporate Citizenship. Online book catalog, journal tables of co |
| League_of_Women_Voters__Materials_on_Natural_Resources_Protection Available brochures and publications on several environmental topics. |
| Okno_Group Publishes books and periodical series on environmental and health care topics in eastern Europe, Russia and Central Asia. Includes Environment & Health Online. |
| Science_and_the_Environment_Bulletin Bi-monthly online publication from Environment Canada, featuring news and information on leading-edge environmental science and technology. |
| United_Nations_Environment_Programme_Book_Shop Distribution point for UNEP publications. Most reports and magazines are only available for purchase, but are few items can be read online. |
| Water_Resources_Publications,_LLC Publisher's online catalog, including descriptions of available books, CDs, and other publications in the area of water resources sciences. |
| Are_There_Pictorial_Examples_of_Covariant_and_Contravariant_Vectors We present pictorial means of distinguishing contravariant vectors (or simply vectors) from covariant vectors (or linear forms). |
| The_Cosmological_Constant An overview of why Einstein added an extra term in general relativity, and why it is still examined. |
| The_5D_Spacetime_Consortium We are a group of physicists and astronomers working on a 5-dimensional version of general relativity. |
| Derivation_of_gravitational_waves_in_Einstein,_Brans-Dicke_and_Rosen_theories_of_gravity_ Mathematical derivation of gravitational waves to quadrupole order in the Brans-Dicke scalar-tensor and Rosen bi-metric theories of gravity. |
| Dulkyn__Scientific_Center_for_Gravitational-Wave_Research Research includes detection of periodic gravitational radiation from relativistic astrophysical objects, investigation of infra-low-frequency variations of Terrestrial gravity field in the role of cry |
| An_Essay_on_General_Relativity This site contains a comprehensive introduction to the basic ideas and tests of general relativity |
| Experimental_Gravitational_Physics_Using_Drag-Free_Satellites Covers current and past projects in experimental gravitational physics using Drag-Free Satellites including the Relativity Gyro, Equivalence Principle, and LISA. |
| General_Relativity_Simulation_Contest The purpose of this Contest is to prove General Relativity using a (simple) algorithm. |
| Gravitational_Lensing A popular site with interactive demonstrations of gravitational lensing. The background material is at a graduate level |
| Gravitational_Waves__An_Introduction This paper presents an elementary introduction to the theory of gravitational waves. This article is meant for students who have had an exposure to general relativity, but results from general r |
| Gravity_Probe_B Gravity Probe B is the relativity gyroscope experiment being developed by NASA and Stanford University to test two extraordinary, unverified predictions of Albert Einstein's general theory of relati |
| Handbook_of_Space_Astronomy_and_Astrophysics_-_Relativity A collection of equations important to both special relativity and general relativity. |
| Hyperspace_at_the_University_of_British_Columbia Includes links to online journals, news and preprint archives, as well as lists of faculty at this university. |
| Interactive_Experiments_in_Gravity Try an experiment that illustrates the gravitational attraction between two objects or use a Java applet to understand how orbits work in strongly curved space-time. |
| Lecture_Notes_on_General_Relativity Sean M. Carroll's lecture notes from a one-semester graduate-level course he taught at MIT in 1996. Notes are in postscript format. |
| NOVA_Online/Einstein_Revealed Profile of Albert Einstein, with additional teaching resources, Shockwave demonstrations, and animations of relativity concepts. |
| Physics_Bookshelf_-_Relativity A collection of articles about relativity |
| Publications_in_Physics_and_Mathematics_by_Walter_Pfeifer A textbook for relativistic quantum mechanics is presented. The Dirac equation is dealt with in detail. |
| QMW_Hyperspace A set of hypertext based services for general relativity research provided by the QMW Relativity group. |
| Relativity Provides information on the history, experiments and paradoxes of relativity. |
| Relativity_bookmarks Rob Salgado's bookmarks |
| Ricci A Mathematica package for doing tensor calculations in differential geometry and general relativity. |
| Shapiro_Radar_Bounce_Test A two part overview of the Shapiro radar bounce test of general relativity. (The two parts consist of a section for normal people, and one for nerds) |
| Solving_Einstein\'s_Equations_in_Three_Dimensions This is a Mathematica notebook showing how to plot light cones in two plus one spacetime dimensions with a point mass. |
| The_Special_Theory_of_Relativity Self-tutorial with short essays, questions and answers. |
| Why_Time_is_Absolute,_and_Relative,_But_Never_Universal An article by Vincent Sauvé elaborating upon a materialist view of the absolute and relative nature of time. |
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What the hell a step-by-step instruction to build a vacuum pump is doing on a site dedicated to the electric helicopter?...I must admit that it may sound strange but I will list you some application that may bother the heli pilot you are. For example, you may use it when building your own self-made canopy, a new composite undercarriage (ask Bert) or a set of custom blade. In fact everytime you will need to press something for quite a long time.This is often the case when you work on something using composite (such as carbon fiber, glass fiber tissue, Kevlar,...), you always need to press the different layer on a shape and keep them in place in order to let the epoxy polymerise.People often use heavy loads, sand bags, their collections of magazines or anything in the neighboourhood looking heavy but they never obtain a regular and optimal pressure on all parts of the work. By using vacuum, you can apply the same high pressure on all parts. How can this be achieved?... Answer: by using athmospheric pressure! All you need to do is put your items inside a polyethylene plastic bag and use a vacuum pump to lower the pression inside the bag.A depressure of -100 mbar gives a load of 100 kg per square meter, if you apply -500 mbar, you will end up pressing 1/2 ton per square meter. Our problem now is to get a vacuum pump and a regulation to do it. You can find some on the market but at a retail price that will make you think twice before buying it. Other solution is to build your own. The solution I will describe here has been validated and I will explain you how to build it for almost nothing.WarningDisclaimer: I decline responsability for any injuries or damage you may encounter while following these guidelines. Be aware you will be doing this at your own risks.You will be dealing with current, so be carefulGetting the material
Fig.1 Fridge compressor unitGo to your local fridge resselers, they often offer to take the previous back when customer buy a new one. And they dont know what to do with them. Ask them if you cannot take one off. You will need a good cuting plier to cut in and out tubes. Please avoid using a metal saw to cut them because the metal dust can enter the tubes and give trouble later. Note Take care to let at least 10 cm of in and out tubing. Pay attention while handling the compressor they are often filled with oil. You must keep it inside. press the last centimeter of the tube to seal it for transportOne admission advance regulation valve OR one glass syringeThis part can be found in almost all old engine (with no electronic advance regulation). This looks like a metallic can like a flying saucer with a tube on top.(crazy definition but I do not engineered these parts anyway) How does it work? It contains a rubber membrane that can move depending on the depression applied at the inlet tube. The more depression there is, the more the membrane moves. An iron wire is linked to the center of the membrane and moves with it.
Fig.2 Vacuum valve front view
Fig.3 Vacuum valve side viewIf you cannot find that part, you can go to your pharmacy and ask for a glass syringe (The bigger, The better). We can also use it for this job. NoteDo not use plastic syringe, they are not adapted for this job.One 220v. microswitchIt should be strong enough to support the load of the fridge compressor unit you have. Speak about this with your electronic part reseller.One manometer
Fig.4 Fuel Pump Pressure vacuum manometerYou will find this item in any car supply store. It is used to check fuel pump aspiration. It as generally scaled from -1 bar to + 5 bar stepped by 0.1 bar. It is really low cost item. NoteThis item is optionnal, but is useful to precisely set the depression value you want to apply. When using foam core forms, you should not apply too much vacuum or the form will collapse on itself. (Max depression for foam core is -0.4 bar, if you apply more, deformation may occur ruining your work.) Always perform some experiments before in order to know the limit of your materials.Some meters of plastic tubingIt should be strong enough not to squeeze on itself under vacuum.A ping-pong ballI bet you are wondering what we gonna do with this ...some plywoodto build the box around the regulation to protect user from electric shock.One spring + nuts and boltsyou can canibalise one from a old camp bed or go to a outdoor shop to find spare ones.One Bycicle wheel rayThis will be used to replace the iron wire connection on the admission advance regulation valve. The original one is too short and the wheel ray is threaded with the same path.Building instructions
Fig.5 Car part regulation principleThe principle is easy to understand. When connected, the compressor will turn ON and begin pumping. As more and more vacuum is applied to the inlet of the valve, the iron wire moves back releasing pression on the micro switch. When the OFF position is reached , the compressor unit stops. Due to unavoidable leaks, the vacuum will lower little by little and the iron wire will come back pushing the microswitch ON, starting the compressor unit for a new cycle. The more the bolt retaining the spring is tightened, the more vacuum depression you will get.Build a wooden box out of plywood in order to put all hazardous parts inside a secured area. Install the valve outside just letting the iron wire go inside. Bolt the microswitch to the base and connect the power wires to it (soldering is just fine). All you need is to install the bolt and spring and connect it to the iron wire coming from the valve. solder a push button guided to the switch by two piece of wood. Job is done... 
Fig.6 Car part regulation example
Fig.7 Car part regulation boltInstall your electric junctions in an isolated box on top of your wooden box. This will be easier for later maintenance. 
Fig.8 Car part regulation overviewSyringe based regulationUnderstanding the principle
Fig.6 Syringe regulation principlePrinciple is not very different from the car part based solution. The only limit here is that the system MUST be fixed verticaly and firmly attached due to the load. When connected, the compressor will turn ON and begin pumping. As more and more vacuum is applied to the inlet of the syringe, the piston moves up releasing pression on the micro switch. When the OFF position is reached , the compressor unit stops. Due to unavoidable leaks, the vacuum will lower little by little and the piston will come back due to the load in the basket pushing the microswitch ON, and starting the compressor unit for a new cycle. The more load in the basket, the more vacuum depression you will get. To build this regulation, take care to fix the syringe firmly. It is best to fix it using collars (like tie-raps) over small strip of rubber cutted out of bycicle wheel tubes. Be careful not to brake your syringe. Take care to limit the piston move with one or two nails. It should only be able to move until the switch is fully pressed ON, not lower in order to avoid mechanical load on the switch. Installing your fridge compressorYou should firmly install your fridge compressor on a wooden plate using the rubber damper you found when dismanteling it. Normally you shoud have let 10 cm of tubing. The last centimeter flattened for transport. We can now cut the in and out tubes in a proper way. Use a tube cuting tool to shorten them to 8cm.Identify the IN and OUT tubes by starting the compressor. WarningSome oil may be projected by the OUT tubes so keep yourself out of the way.On the OUT tube, fix a 20 cm tube. Guide this tube verticaly on a wood stick and cover the end with the ping-pong ball. drill small holes in the ball so that the air can get out. This little ball will act as an oil recuperator. 
Fig.6 Ping-Pong ball installationTo the IN of the compressor you will fix the vacuum tube. On this tube you will add a "T" in order to get one tube to go to the inlet of the regulation and the other one to the bag. Optionaly you may add an other "T" to be able to add the manometer in the chain. But it can be a new source of leaks. 
Fig.6 Tube installationNow seal all links using silicone and tie-raps. Let dry... Proceed with the few tests. You should be able to fix most of the problem by yourself. if not, you can go to the Ikarus Eco8 forum and post your trouble.The final result
Fig.6 Vacuum pump - lateral view
Fig.6 Vacuum pump - top view
Fig.6 Vacuum pump - front viewTips for using your vacuum press
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