Newbies_Kid

I think you can't rely too much on your elastic modulus graph unless you've confirmed that those materials are pure. Alloys can have a variety of strength as the value is dependent on the alloying elements. If any unknown materials can easily be characterized by referring to its tensile properties therefore there is no longer need for materials scientist to rely on complex characterization method such as powder diffraction files, electron energy loss spectroscopy, energy dispersive spectroscopy, glow dispersive spectrum etc..

lemur: Erm.. are you suggesting that no container can hold the outside pressure for ultimate vacuum inside? or are you suggest that even the container is strong enough, still it's most outer electron will loss bond and filling the interior of container? I'm asking this because the behavior of anti-matters which cannot be confined in whatever materials. I wonder if we can create an ultimate vacuum and wrapped it with strong magnetic field, shouldn't we able to do that?? :confused:

Is it possible for us to create a space which absolutely empty with not even single particle do exist in it? Or perhaps is it already exist? please tell me if u know..

"but that transition also happens when the electron recombines with the ion" - this point give me a hint to find the answer, actually i do sputtering for thin film fabrication and still a newbie, i know plasma is ionized gas and usually indicated by the glow discharge, but i want to measure how much the glow discharge influence the process. May be from it's intensity or brightness

How plasma produce the fluorescent?? Is it true when the electron that suppose to ionize the gas which have less energy to cause ionization hit an orbital electron, the orbital electron will just excited to certain energy and back to ground state and emitting the glow discharge or fluorescent? If its true, the glow discharge doesn't means the gas is fully ionized right? if we want total volume of ionized gas, the glow discharge must not appear isn't it?? so what function the glow discharge do anyway?? for me it's just a color... i'm kinda confused right now, help... help..

Yeah, i know the oxide would appear in just some mili sec, but how should i remove it under uhv? After deposition, definitely i will open up the chamber's door to change the target. Even before that, i guess the oxide is readily formed as i stop the vacuum pump when finish depositing.

I want to make a multilayer coating on Si-wafer using RF magnetron sputtering. My targets will be Cu, Al, Ti (in sequence from the top) and my machine capability is only one target per sputtering process. So i assume a problem will arise on aluminum layer because i'm certainly sure that the oxide layer will instantly formed as soon as i open the chamber to change the target for the next layer. I do some study and found that the oxide layer is strongly bonded and have a porous structure. My first idea is to put a negative bias and back-sputter the Al film before proceeding to Cu layer. But i don't know how much energy should the Ions (Ar+) have to clean out the oxide layer and i also afraid if the film will contaminated by Argon ions due to the porous layer of aluminum oxide. My second idea is to do some acid pickling on the film but i'm not sure what solution is effective. If you have any experience or suggestion, please feel free to reply my post. THANKS~~~

"Undopped wafers" thanks for the keyword! Seriously i never used to know about these material before because my background is mechanical engineering. I found the price of undopped wafers in University wafer but i'm wonder why the price for the undopped wafer is much higher than the dopped one?? For example, 15 wafers p-type Si:B [100] 4" 2,300micron thick is sold at $59.00 while a 100mm Intrinsic (100) 380um >20,000 ohm-cm SSP Prime one wafer sold for $150.00 each.. that's was so expensive just like the alumina...nevertheless i will try to ask our local supplier first. Secondly, there are one more type of Si-wafer which attract my attention, the SOI. I don't know how the oxide box are chemically bonded to the substrate and the thin Si film but i'm thinking if i grind out the thin si layer on the top, will the exposed oxide layer could stay unaffected and may not oxidized?

actually i didn't intended to make a chip or something from those Si wafer, currently i'm studying nanoscale thin film and i just want to use the Si-wafer as a test material before i do my real coating on Alumina substrate. The price for alumina is far more expensive and i'm afraid it will be wasted if the chosen sputtering parameters were wrong.So, I will coat using RF Magnetron sputtering and the target's material will be Ti-Al-Cu, and prior to the real coating, all parameters will be tested on Si-wafer first. I chose Si-wafer because it acquired single crystal structure as alumina had. But i'm getting confuse here when the supplier ask me for which one, N-type or P-type?? What are their differences based on structural kinetic and thermal properties? If you had any experience on Si-wafer deposition, which one can result good thin film? I search in most material's info website but nothing could help me so far

Can somebody tell me what the differences between P-type & N-type Si Wafer?? If i want to use it as a substrate to be coated with a metallic coating, which one should i preferred to choose? and why?. Thanks

I have a piece of Alumina (Al203) to be coated with metallic multilayer of Cu-Al-Ti. I choose to use evaporation method instead of Plasma sputtering because some books says Plasma sputtering PVD cause some impurities incorporated in thin coating.. So my problem is to find the phase transition diagram of those metals because i need to know the pressure and the temperature at which the solid metals start to vaporize.. Just their critical point (P-T diagram) would also be helpful.. Thanks ...

Hydrogen engine may much heavier than a battery pack and single DC electric motor. In addition, we need a gas tank & compressor if we use hydrogen engine. But i'm confuse, solar sailing??? isn't it a propellant system for space craft program??

Gases are not dense compared to liquid and solid, their molecular distance is far between each other.. so i can't really imagine the mechanics of the system. i think the efficiency over volume is very low because those gas will just diffuse between each other... hwever i love this idea.

Since 2009 my country used two common petrols which are RON 95 & RON 97. Since the RON 95 is cheaper than the 97, it was usually chose by people. Before the petrol price hikes we use 97 type. But, recently i noticed that there were many car's accident case which involve car explosion and normally cause death. Although the crushed from the accident weren't so great, it always follow up with explosion especially when the car been hit from behind. I think the RON 95 was responsible for the explosions and i'm going to do some study on it. So your help is needed.

Since 2009 my country used two common petrols which are RON 95 & RON 97. Since the RON 95 is cheaper than the 97, it was usually chose by people. Before the petrol price hikes we use 97 type. But, recently i noticed that there were many car's accident case which involve car explosion and normally cause death. Although the crushed from the accident weren't so great, it always follow up with explosion especially when the car been hit from behind. I think the RON 95 was responsible for the explosions and i'm going to do some study on it. So your help is needed.

Since 2009 my country used two common petrols which are RON 95 & RON 97. Since the RON 95 is cheaper than the 97, it was usually chose by people. Before the petrol price hikes we use 97 type. But, recently i noticed that there were many car's accident case which involve car explosion and normally cause death. Although the crushed from the accident weren't so great, it always follow up with explosion especially when the car been hit from behind. I think the RON 95 was responsible for the explosions and i'm going to do some study on it. So your help is needed.

I agree with Tony, perhaps that plastic's bowl is a kind of polymer that having a week polymeric chain. The wave radiation might cause the chained monomer to vibrate until it reach the resonance state and weaken the chains ( may be due to elongation or yielding). The monomer will freely vibrated and bump into each other which could produce heat.

force and time are inversely proportional. An object with 100 units of momentum must experience 100 units of impulse in order to be brought to a stop. the greater the time over which the collision occurs, the smaller the force acting upon the object. Thus, to minimize the effect of the force on an object involved in a collision, the time must be increased. And to maximize the effect of the force on an object involved in a collision, the time must be decreased. In this case assuming that you're about to hit your belly with a rock and a pingpong ball at the same speed. You will feel getting hit by ping pong ball give more pain because the time duration of the impact is shorter than being hit by a rock. It similar when you throw an egg into a mattress instead letting it hit a wall.

When no oxygen pumped into brain this make the animal lose consciousness. As the brain already dead, the pain receptor will no longer functional and the animal feel no pain. Doesn't this quite logic isn't it. You never conscious when your skin get scratched by razor blade unless you see it in the mirror.

Agreed. We muslim must sharpen the knife as sharp as possible to avoid pain for animal.

I'm a muslim and i read Koran. In Koran, God said when the world close to end the Dajjal will born between syria and Iraq. He is not human neither devil but he is the most evil creature of all time. He kill his own parents as soon as he was born and he possess single eyes and a word "Dajjal" written on his forehead (in arabic of course). but this not what i want to tell here, i only want to share my believe that Koran said Jews, Christians and Muslims are the domain religions that exist on that day. The Dajjal will try to make all human on the earth left their religion behind and follow him. Muslims are so many at that time but unfortunately they are incredibly weak physically and also spiritually. God describe the number of Muslims like the bubbles in the ocean, so many but yet very weak.

why filled with liquid? why don't just throw a brick tied with a ballast tank into the sea?

hurmm... so i just assume the gas trapped in a membrane-like layer to make it looks possible. So i think i will use a hollow pipe because if you use pipe B, there will be a burst of water bubbles coming out at the top outlet of the pipe. Considering the high pressure from bottom, i'm afraid the water burst can flung nearby things up high. In 30000ft depth or less equal to 10000m (am i right?) the pressure applied against the gas is about 100000kpa (every 1 metre depth the pressure increase for 10kpa). So use the formula P = F/A, we can find the rising force of the gas if you know the cross section area of the pipe. Assume the pipe area is 1m^2, so the exit force will be 100,000 N. Then use equation F = Ma, we can calculate the speed/time (acceleration of the gas). The mass of the gas will be so small and this means it will go up very fast. To calculate the velocity, you can use the kinematics equation of V^2 = U^2 + 2a (r - r0). Initial velocity = 0, and we have the velocity.