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Everything posted by EL

  1. Commercial gasoline, such as what you fuel your car with, is in fact a mixture and the higher the octane number the more expensive it is. That is why the smell will not be consistent unless you specify the components of that mixture and their percentage. Hexane upwards are acceptable, it is when pentane and butane increase that we feel heavy on breathing. Propane, ethane and methane are not to be fiddled with, they can kill you, do not experiment to smell them intentionally; especially while you are sleeping.
  2. Most flash powders were based on magnesium and potassium perchlorate, which gave a light rich in blue and UV, suitable for early emulsions that were only sensitive in these regions, but when orthochromatic and panchromatic plates became popular, strontium and barium salts were often added to increase the amount of green and red light. Other metals such as aluminium, zinc, cerium, zirconium and thorium were also used at times in place of magnesium; aluminium gave slower combustion and the cerium mixtures less smoke. They are still very hazardous. Modern Xenon stroboscopic flash bulbs are the best if it was photography that was originally intended.
  3. LKL, I forgot to tell you that rinsing the ground flour by acetone followed by rinsing with ethanol, will remove the wheat germ oil from the way, and that you may evaporate those "rinsing agents" to have a concentrated oil extract if the quantity was big enough. Some husk waxes too shall be in that extract. This exposes the cellulose for subsequent operations. The target is to hydrolyse the macro-molecular structure to obtain soluble sugar forms. The function of diluted HCl is found in supramolecular chemistry and it binds ionically at some critical structural bonds and make them vulnerable to hydrolysis. HNO3 denaturises the resident proteins and opens their structures for hydrolysis too. Finally, it is NaOH that does the job. It is absolutely critical that the acidic reactions be applied on already wet meal that was left for at least 24 hours after adding enough distilled water to cover the flour after mixing thoroughly. Gentle heating is recommended over boiling with HCl and HNO3. When Conc. NaOH is applied, better results can be obtained when addition is at room temperature, then after 4 to 6 hours gradual heating up to the boiling temperature is carried out while constantly stirring. In a couple of hours the meal should be syrupy clear with a yellowish tint for partial caramelisation that could not be avoided.
  4. Very easy indeed. For very white flash bang grenades: Add a cup of corn oil to 4 cups of corn and a tea-spoonful of common salt. Heat in an open pan while mixing thoroughly, using a wooden spoon at arms length. Get ready to dodge the small white flash bangs.
  5. Butyric and Valeric acids, ouch, they smell horrible.
  6. Reading this thread was a real pleasure. May I have the honour of directing your collective attention to the fact that "Good and Bad" is a psychological verdict? Naturally there are some hardwired reactions in our brains, and here are some of them for the interested. 1- We prefer oxidizing odours over reducing odours because we need oxygen to breath into our blood by exchange mechanism. This rule of thumb is very general and could hardly have any exceptions. Mint (menthol) is translated as cold! All aromatic, alcohols and some ketones and very few aldehydes are pleasant while most organic and inorganic acids are pungently repulsive due to its corrosive effect on the lungs. 2- Thus similar to the first rule, we tend to favour the reduced forms (subject to oxidations) over the oxidised forms (subject to reduction); and we favour water over strong deviations from pH = 7. 3- Bitter, sour and sweet are tastes that mingle with odours of almond, lemon, and vanilla, and they proved to be desirable and not offensive. 4- Unsaturated compounds are favoured over saturated compounds, such as benzene over hydrocarbons such as gasoline. 5- Most of the poisons and harmful chemicals that escape from the above classes are offensive when they have odours. 6- There remains one group of conditional indifference such as amino acids that offend some people while are a pleasure for others. And while all organic compounds with smell, made of 4 carbon atoms offend me, some may not mind it. It is a cultural adaptive reaction, where one is used to the smell of his home while a guest might ask for opening the windows before fainting.
  7. Thanks to YT2095 for deleting my Dragon Eggs before it was too late. I was that close from being banned for my ignorance of the rules. However, recognising what the OP wanted, I posted the best "True Flash" procedure, which was composed of Aluminium wool being oxidised in air and triggered by an electric current, just like the good old days flash-cubes for cameras. If plenty of Oxygen was trapped with the wool inside a test-tube, with the electric electrodes passing through a cork, the aluminium will consume the oxygen forming the oxide without any explosion in the absence of other air gasses that may expand. This is the safest flash source that one could ever dream.
  8. Although I agree with the correct information that was posted in reply to your tricky question, when one attempts to answer a question such as "What is the molecular weight of graphite or diamond?" the reasonable answer is that the question is a wrong question. The modern atomic theory tells us about elements and their valence. As my friends explained to you, polymers and crystals do have an infinite extent of its structural periodicity. But Sodium Chloride too comes in crystalline form yet its SMALLEST unit of identity is composed of two atoms bound ionically, it is THAT _smallest_ unit of the substance that we call a molecule, hence in case of pure elemental substances the molecule is atomic. Gasses have a much clearer concept of molecules, and that is because of the diffuse nature of gases. When it comes to proteins we have primary chains bent into secondary planes folded into tertiary structures; another path is twisting a chain into a secondary helix that could bend into a tertiary and folded into a quaternary structure as well. Since amino acid sequences are reportedly a code, then we do not expect periodical repetitions to exist meaningfully, and the unit molecule could be a chromosome or an organelle, but we do not treat them as molecules. They are biochemicals with a level of complexity that exceeds the equivalently weighted pure materials. Polymers, have periodical molecules and macro-molecules, which are evident from the name and the macro-molecular weight. Poly ethylene, Poly carbonate, Poly propylene, Poly Urethane, etcetera, all have a name after the word "Poly" indicating the name of the periodical molecule, which is the smallest unit of identity, but the macro-molecule is physically disconnected from similar macro-molecules and they are identified by the degree of polymerisation. To sum this issue up, we have macro-molecules that can grow until you run out of the substrate micro-molecules that are being bonded to the macro-structure. Of course there are stereogeometrical restrictions, such as when the active end of the macro-molecule is screened or terminated or even hidden inside the coiled chain, and so on. Some polymers extend in two directions linearly, and others extend in two dimensions forming membranes. Then we may look at the problem in terms of identity, which holds the properties of the substance. This brings us to the point of classifying molecules into micro-molecules, which are always members of a homogenous substance and macro-molecules that could be homogenous polymers or heterogeneous aggregates of matter. Take for example RNA, which means ribonucleic-acid, it took its name due to the identification of sugar-ribose molecules and nucleic acids, which are a limited subset of amino acids, and then there is the phosphate, which is not even included in the name. We identify them as constituent molecules within the heterogeneous-macro-molecule. Therefore, the issue was never how big, but rather how small; we always look for the smallest group of atoms that identify the molecular structure and not the biggest, the properties of which only the molecular weight is of great significance.
  9. It depends on "how good looking" a chemists sink should look like, in your opinion. On campus, we had those chemical resistant sinks in the laboratories, but how many colours do you think I counted one day in one of them? I lost count.
  10. Metal nitrate is water soluble but metal sulphate is not. Then you have to test if the discoloration had ferric sulphate involved or not. You say that the surface is etched as well, and there is nothing you can do about that else than using moulding templates' high speed motor driven grinding tool-tips to smooth it out. Then you can finally polish it. Make sure first that the etched grooves are not too deep because living with discolouration is better than living with a sink that has a hole in it.
  11. I totally agree, and I really do not encourage teenagers to fiddle with explosives, even the cautious genius ones. In fact, even fire-crackers are not that safe as advertised and they cause many accidental injuries. One should be careful when posting information that could be misused. I learnt my lesson.
  12. There is no harm in testing, and I encourage the OP to use your method first to gain experience and know the difference.
  13. You are absolutely correct. Have you ever tried mixing aluminium powder with red lead oxide (used for painting wood to protect from insects) and then ignite it? If you did not try it, do not try it, it is explosive; or be very very cautious.
  14. Oh! But I did know that very well, however what works for silver does not work for stainless steel sinks. Industrial abrasive compounds are complex mixtures, not just a filling powder. I may disclose the fact that aluminium oxide is a popular ingredient in car-body-polishing-compounds, while more expensive and more potent compounds contain silicon carbide powder, but calcium carbonate or zinc oxide are usually used as fillers and vehicle media to homogenize and distribute the effective abrasive grains as well as a whitener. Pumice and gasoline were common ingredients for brass polishing compounds in England long ago. The modern technology combines the mechanical and the chemical effects to maximize the polishing results. Now it is your turn to test it for yourself, because I am quite sure that aluminium foil will "stain" (discoloration) corroded stainless steel, and it is not as easy as you think that it could be removed especially if it was strongly embedded and oxidized. I understand what you say too, and I like the quality of your posts too, but here I am an authority with an academic degree combined with field experience. However, you may continue to argue if you wish and I shall adequately reply too.
  15. That was a very good link, and he should look for flash recipes. As I said above, aluminium would be the practical metal of choice. Don't push your luck.
  16. Indeed. And in fact rather than the impossible "solvent of whole wheat grains", it would be a best advise to use step solvent extraction methods, where cellulose and unbranched glucans may be dissolved and separated in several ways, that include: separation of amylose leaching from starch granules during gelatinisation, centrifugation of retrograded amylose, removal of amylopectin branches by enzymes, removal of amylopectin from starch solution, preparative ultracentrifugation, size exclusion chromatography, field flow fractionation and electrophoresis. However, I was under the impression that the OP anted a cheap method to prepare a solution regardless of keeping the original molecules intact or not, and that is why I suggested meal digestion, and in fact I had prolonged boiling in NaOH for long time as the best known crude and safe method. Some colleagues have reported that using dilute HCl as a primer followed by dilute HNO3 (with molar precise quantities) would shorten digestive dissolution time in hot Conc. NaOH.
  17. I used to manufacture metal polishing compounds, which are patented proprietary secrets. That is why I fully know what I am talking about and bicarbonate will not achieve the objective and neither does extremely soft abrasives. The reduction power of ammonia is precisely required to achieve what patented proprietary chemicals will in removing the oxides and chlorides of metallic alloys on stained stainless steal, which is not pure iron at all. The flat grinding stone at 1000 grit or more is empirically tested to polish and sharpen SS knives, while the pumice stone powder is used as a vehicle when wet with water. What you do not seem to know is that aluminium foil itself will stain the stainless steal with aluminium oxide if it was rubbed into the corroded surface. Kindest regards.
  18. EL

    When does life begin?

    This issue is a very intricate one, and may not be judged superficially. What the law must focus on is the consciousness of the human beings affected by any verdict. It is not the neonate's consciousness that worries the society as much as that of those who feel hurt by the acts of treating neonate's as if they were dog-meat. While Bush-Junior is an emotional idiot, he is accidentally right on this issue, because his strong emotions were devastated by the issue. If a mad psychopath held a live kitten against a sensitive woman's will and began to snip its limbs and cut its guts in front of her, is it the kitten's rights that are obviously violated or is it hurting the woman's feelings that compose the damage in a court case? The act demonstrates a bi-cruelty and disrespect to all moral standards. However, the same Bush-Junior does not seem to be equally affected by the numbers of dead American soldiers in Iraq or their pictures! He did not seem too concerned by pregnant women dying during bombers' raiding civilian zones. That is why hypocrisy and double-standards are doing great damage to the credibility of civility and moral standards, when it comes from top executives who are chosen by the people. We need to make up our minds about the world we wish to live in. What shall it be, a brutal jungle of cannibals or a civilized peaceful world?
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