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Engineering Talks

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  1. What's new in this club
  2. Hi Harkan I suggest you get acquainted with artificial intelligence and Machine Learning and simulation. As we begin life with artificial intelligence, it's best to have a background in it and relate it to your specialty. You can also find software that runs in the cloud. As a mechanical engineer, you need to keep up to date and upgrade with knowledge and technology. There are many webinars (you can find some on eventbrite,and brighttalk) that can help you improve your skills. Do not sit back and watch the success story of others, make your own. Regards Samira Gholizadeh
  3. Many of the comments here are salient, but there is one area that has not been mentioned....the inadvertent use of petrol in a diesel engine. I am fortunate enough never to have done so, but I know many who have used the wrong pump at the filling-station. What few realise is if you drive a diesel and realise after a few seconds of filling the error that has been made, it is possible to just fill the rest with diesel without any real problems. it will run a little rough for that tank, but will revert to normal when next refilled. It IS critical though that it is only a little petrol/gasoline though...if it is a lot - say greater than 10% - it would be a drain-down for safety, but less than that should not cause any great issue. Whilst I have never tried it nor know any that have (other than a complete refuel....doh!), due to the need to physically ignite the cylinder charge, I very much doubt that this would be the same for diesel in a petrol engine...
  4. Hi everybody! I'm a freshman mechanical engineering major and I'm getting to know more about opportunities I have as a student. What should I be doing over the summer after my freshman year to enhance my knowledge/experience?
  5. In my final project I have a tube that is insert to a cylinder and I want to add to the tube some handle that stop the rotation between the tube to the cylinder .(only the button of the tube inserted to the cylinder and I doesn't want to add holes in the cylinder , I want some handle on the tube that will be in the part that outside of the cylinder and with the friction force stop the rotation, like a breaks ) . Does some one know a suitable device for this task ? Or that you suggest to me to add some inners between the tube to the cylinder ? If yes how do I calculate the inners thickness ? See the attached draw. Thanks for your help ! Draw.pdf
  6. Anyone who has a thesis either capstones or experimental. I would gladly appreciate it, I am a 3rd year student studying mechanical engineering course. As part of our research development, we had assigned to look for any research thesis. Anyone who can helped, Thank You Very Much In Advanced. google is helpful but not in this topic because various parts is needed such as introduction, literature review, methodology, results and discussion, summary, and bibliography.
  7. Gasoline, or petrol, ignites too soon (predetonation) in a diesel engine due to diesel engines high compression ratios. That causes some reverse loading, very high stresses, mostly on the cylinder rods which may eventually fail in high compression load and bearing wear. Multifuel engines must be designed for extra high rod loads.
  8. You’re all right, but there are multi fuel outboard engines (based on petrol engine design) used in defence running on various fuels, kerosene, jet fuel or diesel (low compression ratio with spark plug support). Downside is that the engines are not compliant to enviro regulations, due to incomplete combustion (engines are “Smokey”). See Mercury Racing Optimax JP and Evinrude E-TEC.
  9. Compression Ratios are also very different, Diesel run with compression ratios from 17~21 to 1 where gasoline engines can only run at compression Ratios of 8~11 to 1. Gasoline will detonate at much lower compression than what is needed for diesel to reach self ignition point. A real diesel engine will be more efficient overall since it will have the ability to operate at higher compression ratios. If a petrol engine were to have the same compression ratio, then knocking (self-ignition) would occur and this would severely reduce the efficiency, whereas in a diesel engine, the self ignition is the desired behavior.
  10. we cannot use petrol in diesel engines or vice versa because diesel and petrol has different characteristics (flashpoint) every engine has unique design depends on its fuel to be use. petrol and diesel engine has different engine stroke cycle specially during intake and ignition stroke Diesel intake stroke: enters hot air ignition during power stroke: sprays pressurised diesel fuel on the combustion chamber by means of injection nozzle gasoline/petrol intake stroke: enters air and fuel mixtures by means of carburator ignition during power stroke: ignites by means of sparkplug sparks inside combustion chamber @ highly compressed air and fuel mixtures
  11. The flash point of petrol is high also the compression ratio, spark plug used for Petrol engine, valves used for injection of fuel in diesel, is it OK
  12. I don't know how to install or get the Auto Cad software for free. If anyone of us is aware of this please tell us, so we can learn quick with the tutorial and software. Thank-you 😊
  13. Well, it can't be entirely fixed whether the Re range under which the flows are classified. In convention, for internal flows, Re < 2000 is regarded to be laminar 2000 < Re < 4000 is regarded to be transitional flow Re > 4000 is most often turbulent. On the other hand, for external flows, Re > 5E5 is said to be turbulent
  14. It is not preferred to weld material in normal atmospheric gases, either we need to provide any shielding gas or produce it while welding; so that the weld can be done without any impurities. These impurities or oxides (formed in contamination with oxygen at high temp.) decreases the mechanical property of the metal or alloy which may effect the same in long run. There are many kind of shielding gases out of which few are inert and others are semi-inert gases, which basically doesn't produce any harm to the metal during welding moreover they protects the metal from contamination by other gases. Inert gases basically used are Argon and helium gases; whereas semi inert gases are nitrogen, carbon dioxide etc. Basically a beam of non-reactive nitrogen gas is thrown at the welding to shield the weld so that no oxide formation takes place. This increases the weld penetration and arc stability. Moreover nitrogen helps in prevention of metal/alloy from pitting and nitrogen loss from metal. Hence increasing the metallic property of metal.
  15. Overdrive or OD is the highest gear in the transmission in an automatic car. It brings the RPM of the engine down at a given road speed to facilitate better speed and fuel efficiency. It also helps your car to provide the best performance in higher speed cruising. Overdrive helps when you drive at more than 50mph.
  16. To check your score Take the quiz https://engineeringtalks.com/quizzes/quiz/43-mechanical-engineering-concepts-quiz-1/
  17. Explain what are the approach used in manufacturing for QA?
  18. Disk brakes work on hydraulic (liquid power) system where in pressure is created on a disk attached to the freewheel. the fluid pushes the brake shoes from both sides of the disk which brings the disk to stop (naturally the wheel to stop). It is just like the way you hold a spinning disk by your hand. It is visible from the outside (obvious). Drum brakes are not visible from outside. they form the center of your flywheel. the basic idea is that if the center of the wheel stops, the wheel obviously stops. This mechanism works mechanically (using wire). The break shoes aren't visible from outside they are in the drum (center of the wheel). when brakes are applied, the string/wire pushes the break shoes against the inner side of the drum bringing the wheel to a halt. Drum breaks and Disk breaks have no difference in their effectiveness. They are both effective. It is just the design which suits the bike/car. Disk brakes look shiny giving complimenting the rims and giving it a elegant look.
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