CaptainPanic

I have to say that my mouse pointer hovered over the negative reputation button because of this post... but it made me laugh too hard to aim well, and I clicked the green one by accident

And I am sorry that I mistook you for a spammer. You're either really good , or this was a case of the moderators (well, just me, actually) acting too fast. I have restored the links, since it seems you don't have commercial intentions, and I don't see how we can answer your question without those links.

Maybe he just wasn't much of an early bird?

Done

! Moderator Note Dear Victor, I am not sure whether your question is genuine, or just another cheap attempt to draw traffic to a commercial website. If this is genuine, I apologise... but spammers are quite cunning these days, so our tolerance with people adding links to commercial sites in their 1st post on our forum has dropped to zero. If your question is genuine, then I hope you don't object that we have some rules on our forum. Please check specifically section 2.7 of the rules. If this is genuine and you login again, I propose that you copy-paste the specs of both microscopes and paste them in another post. Then some other people can have a look. I don't want any brand names, and no company names, and certainly no link to another website. [edit] ! Moderator Note Seems victor is a real person, not a spam bot, so I have restored the links.

This cartoon does not remind you of any threads on this board. /me makes Jedi hand gesture

! Moderator Note I have updated and improved your post, so that it complies with our forum rules, specifically section 2.7, which says: Welcome

Are you talking about normal electric engines? Or any specific new type of electric engine? I doubt that the power output of any engine is related to the type. The largest combustion engines are really huge... Jet engines are combustion engines. The largest are more than 100,000 hp. The efficiency of electric engines is very high. They are used a LOT... just not on cars, because the bottleneck is the availability of electricity.

rigney, please. We have asked multiple times now if you can please be a little more clear. We sometimes really don't understand what you are talking about, or how your comments are related to the previous posts. So, on behalf of everyone else, could you please be more clear?

alpha2cen, the assumption that the entire layer of 3 cm thickness has a 16.6°C temperature difference is completely wrong. In addition, as shown in the link regarding Natural convection, the air will rise in specific spots, which causes hot air to flow along the surface to that spot where it rises. This can cause much larger forces... I am afraid that the number you give is completely meaningless.

We are talking about a temperature difference, so the different zero degree reference points of the scales of F and C are irrelevant. You just divide by 9/5 to arrive at 16.7°C or Kelvin . Btw, I believe this is just a case of the boundary layer theory of heat transfer phenomena. If you have a cup of hot coffee (or a glass of cold beer), there is a layer of air immediately around that cup which has the temperature of the cup, not the air. And then there is a gradient which approaches the air temperature as you get further away from that cup. Such a boundary layer is typically very thin, but on the ground, which is not very smooth, this layer can be thicker - either because there are some stones or some grass to prevent mixing of the air. According to the wikipedia article, this layer is 1-3 cm thick. I call b***shit, and say that the variation in that layer thickness is a lot more. On smooth surfaces, like stone or a road surface, this will be less. And on very rough surfaces, like a grassfield, it may be more. (Also, it can be debated where we start measuring). What really matters is how strong the natural convection is, which is caused by temperature differences. This natural convection will effectively limit the thickness of that boundary layer. The reason that the heat transfer between this boundary layer and the rest of the air is so poor is because it is mostly stagnant. It doesn't move. Higher above the ground, air moves more, and therefore mixes better, which massively increases the heat transfer. It is also no surprise to me that this temperature difference of 16.6°C is mentioned. I think that in certain cases it can be even more, when you have a nice dark smooth surface. There are cases reported of people frying some eggs on a hot surface which was heated only by the sun. That requires at least 100°C. Since desert air temperatures rarely exceed 50°C, that implies a temperature difference of 50°C (three times more than in the wikipedia article)! p.s. Spyman, don't think that anyone tried to be rude. Ophiolite, even though it was probably unintentional, your comment was interpreted as rude. Apologies will instantaneously fix everything.

First of all, the gas you produce is probably a combination of H2 (hydrogen, odorless, although very explosive) and HCl (a very strong acid). The conversion to H2 is not complete. Secondly, you probably want to rebuild your setup, so that it gets inherently more safe. Limiting your HCl flow rate will also reduce the reaction speed. Finally, if your goal is to make hydrogen, there are safer ways to do that. Electrolysis of water is probably safer.

michel123456, We discussed this among moderators, and although this is science-related, we do not want to allow anyone asking for budgets on our site. Our rules (specifically section 2.7) are quite clear: don't go around making threads to advertise [anything]. Basically, an opening post should at all times start some discussion or contain a question. In this particular case, it may be a noble and honest project, but if we start allowing these, then where would we draw the line? Each advertisement would become a discussion item! And actually, in this particular case, the post got reported and was discussed before we took action. Normally, spammers get banned on sight, and their posts thrown into the deepest pits of the internet. Please note that Pselaphinae was not banned. There are other sites where you can advertise a project and ask for funds. Our forum is not the place. But we would gladly help to develop the scientific part of the project, with advice and answers to questions!

The air at the high pressure end will go to the low pressure end until the pressure is equal. So, yes, you're right. For the same reason wind does not go vertical. At 10 km above where you are right now, the pressure is very low. The statement you made first is true only for a horizontal situation. The gas itself has a weight, which exerts a pressure downwards because of gravity. This is why there is higher pressure at low altitudes. You need a chimney effect to achieve this. This does exist, and it is called a solar chimney, or a solar updraft tower. It looks a little different than what you describe, but I hope it is still useful for you.

! Moderator Note To everyone, References It is recommended to include references for your claims, because your opponents in the discussion will refuse to believe you if you don't. If your opponents ask for a reference, you have to provide a reference (or explain why the request is irrelevant). Biased media, biased references You cannot dismiss references because in your opinion, they happen to be from a biased media. If you do so, you dismiss something that could be a fact, based on your opinion. At that point, the discussion becomes a fight. If you want to dismiss anything, you must counter this with a reference of your own which shows it is wrong.

Big eye strain: Not so much eye strain: I'm really sorry about my reply. By the way, is this homework?

Lignins are a part of wood, and will therefore decompose (hence the lignin degradation that alpha2cen mentioned) and form all kinds of nasty chemicals which will pollute your methanol. In fact, I think you're lucky to get even 10% methanol from your wood pyrolysis. the other 90% are undesired components. Maybe alpha2cen talked about a pretreatment - the lignin will probably still decompose and still form some degradation products. And in pyrolysis, that is only worse.

Eeh... alpha2cen, that is a fermentation. I agree that you can make methanol from wood through some pretreatment and a fermentation, this is not the conventional way. And also, it is not the topic of this thread! The topic of this thread is to make methanol from wood through pyrolysis: Wood --> [Pyrolysis] --> [Separations] --> Methanol

chilled_fluorine, please stay on topic. Not everybody is a native English speaker here. On topic again: the term "wood alcohol" is an old synonym for methanol. Methanol, according to wikipedia, was produced by the destructive distillation of wood. Nowadays, destructive distillation is called pyrolysis, and wood alcohol is called methanol. So, using pyrolysis, alpha2cen said, that means you get some lignin decomposition products too. So, to make a long story short: yes you can make some methanol by heating wood in absence of air (especially oxygen). To answer the question what works better: fresh cut or dry, I am guessing that it's dry. The simple reason is that fresh is more difficult to heat. The reaction of some components in the wood to methanol will not require water (I think), so its presence is not necessary. But I repeat: this is only a guess. Unless someone has tried it and reported it somewhere on the internet, this will be difficult to answer. But you're better off using the term "pyrolysis" in your search for an answer. Most research done at the moment uses that keyword. [edit] apologies for editing this post while chilled_fluorine was already replying to it... but since chilled_fluorine commented on grammar (again) rather than the science of pyrolysis, I don't think this should be a problem.

The calculation seems correct, but the underlying assumptions are probably a little too simple. It is less than you calculated, for a number of reasons: 1. A part of the air inside the fridge is already cold, and does not cool when you close the fridge. However it is already at the atmospheric pressure. This reduces the effect a lot. 2. Your fridge door leaks air. 3. It takes some time for the air to cool down completely. After just a few seconds, it will not be completely cold yet. 4. It depends if your fridge is full or empty. If it is full, all those cold products will help to cool the air quickly (because of a larger surface area). An empty fridge will probably suffer less from this phenomena. My experience is that you need to pull quite hard on it. From that, I would guestimate that the actual force is in the order of 100 N (it is comparable to lifting something of roughly 10 kg).

I would do as Keith said: take a white sheet of paper and place it on that spot: it should make that spot more bright if it is a reflection, and less bright if it is coming from a source in your floor. It might be that something from outside caused that light. Could you elaborate a little on this? It sounds like you suggest that in the years leading up to WWII, people deliberately put radium in their floors? I googled for it, and all I found was that some companies (esp. in Paris) manufactured radium products, which left some residues in the floors. We're talking about only about a hundred cases in Paris. How would that same situation ever occur in Moontanman's house, which is on another continent, and was built after the Radium craze was over?

Buy it. Just get a nitrogen cylinder (it's essentially a pressurized bottle of nitrogen) with a gas pressure regulator. This is the method that everybody uses in the lab. Nobody makes nitrogen. Nitrogen is essentially a waste product from oxygen production (which is what alpha2cen described in the post above) - and it's pretty cheap. Renting the cylinder and the regulator, as well as delivery to wherever you need it, may still result in some costs.

I'm not our local expert, but I am willing to bet that the first question you will be asked is: What operating system (name, version #), what browser (name, version #) do you have?

! Moderator Note Dear JamesThomas, Please check our forum rules, section 2.7, regarding making a thread to advertise an external website. We will never approve any posts which suggest people make any donations, and then gives a link to another website. We don't care how innocent it is. For that reason, I have removed every url which lead to a website with a "donate" button or something. Please be so kind not to post those links again. If any moderator sees the links to that project again, you will be banned as an ordinary spammer.

If we would construct two islands, and conduct the experiment, I would see little problem. If all participants are volunteers, then the only concern that comes to mind would be the cost of this, which would probably be quite feasible. I object using an actual independent nation, with people who already live there, for this experiment. Those are not volunteers. It seemed to me that this is what was proposed. Hope that clarifies things. Sorry to have caused a miscommunication. Regarding the lack of Romney supporters: The fact that this is not an American forum, but rather an international forum might distort things in comparison to the election results. For example: the large majority of Europeans support Obama (and the democrats in general), according to these sources. The same goes for India. It seems that the English speaking world (excluding the USA) simply favors Obama, not Romney. It's not very strange that this is also what we find at this forum.