OldChemE

I don't know what exact type of steel was used in the titanic, but it is worth noting that below a certain temperature, certain steels experience a situation where the yield strength rises above the ultimate strength. The required temperature is warmer than typical winter ocean temperatures. When this happens, and a stress is put on the steel (such as due to an iceberg), the steel fractures instead of bending. This was the cause of some of the Liberty ship hull failures in WWII. The point is that steel hulls can fail even without being weakened in advance.

Maybe the books are mixing something (a typo??) or you are misunderstanding. There are two types of cell division: Mitosis and Meiosis. Mitosis is the normal cell division (NOT sex cells). In Mitosis the parent cell duplicates its chromosomes first, then divides once, producing two identical cells having the same 46 chromosomes (called diploid cells). In meiosis (sex cells), the duplication of chromosomes happens once (like Mitosis) but the division process happens twice, producing 4 new cells, but each one only has 23 chromosomes (called haploid cells, or gametes). Thus, in Meiosis, one parent cell produces 4 sex cells. Could that be the 4 you are reading about??

In some form or another they've been around a lot longer than that. When I entered the US Navy in 1969 the doctors used pressure guns that shot a high pressure stream of vaccine. 5 or 6 vaccinations at a time-- we just walked through the room as they shot us in both shoulders. Based on the link I would say that the 1960's version was cruder-- it left a big enough hole that we left the room leaking fluid.

Carbon has the capability to form bonds using multiple numbers of electrons. it can form single, double, and even triple bonds that are stable and have no charge. This allows CO2 and CO. The problem with CO3 is that there are too many available electrons in three oxygen atoms for Carbon to form a neutral bond.

I don't have my chemistry books handy (someone who does can clean up my mistakes on this), but if memory serves correctly: In the case of CO, Carbon can contribute 2 electrons to the bond, and oxygen 4, making a triple bond. Thus, The carbon atom (which has 4 electrons) sees 6 in the bond plus its other two making 8, which satisfies the octet rule. Oxygen, having 6 electrons, sees its two plus the 4 it shares and the two from the carbon atom for a total of 8, which also fits the octet rule ( :C:::0: ). This is stable with no net charge. In CO2, we have ::0::C::0::, where Carbon shares two electrons with each oxygen atom, and each oxygen atom shares two with the carbon. All the atoms still see 8 electrons, which satisfies the octet rule. There just simply isn't any combination like this that works for CO3

It may also be that since Chlorine is much more electronegative (being in group 7) than Boron the most energy efficient configuration favors hybridization of the Boron.

To elaborate a little on what is above, mutations arise from a variety of causes in terms of changes in DNA (cosmic rays, among other things can damage DNA, which can produce a mutation).

Mutations in an individuals sex cells can be passed on to their children. At this point, the question becomes "How will the DNA change affect the child?"

In the extreme worst case, a mutation can prevent proper development-- and the child never survives to birth.

Slightly less worst case would be a mutation that allows the child to live, but either prevents the child from living to adulthood or prevents the adult from being able to have children. Such a mutation will not continue in future generations (it goes away).

Next on the list is mutations that are innocuous--they neither hurt or benefit significantly. A good example is ear lobes-- some of us have ear lobes that hang down and some are attached to the side of our neck. This type can be passed on to future generations and adds to our genetic diversity.

Top of the list is mutations that actually enable an organism to survive better and/or produce more offspring. Because these mutations survive better and/or produce more offspring, they tend to become a larger and larger part of the population in future generations.

The reason for improved survival is assumed to be because the mutation works better in the environment. When an organism acquires this type of mutation we say it has "Adapted to its Environment."

The important thing to realize is that organisms do not choose to adapt to their environment-- it is the random DNA change that makes it happen, but because other mutation types don't help survival as much, the favorable mutations build up over time in future generations.

Back to the question of how numerology and mathematics differ. Mathematics is a tool. The numbers are meaningful only in context. In order to use the tool in real life you have to first develop a theory of how to represent a situation mathematically, produce evidence supporting the use of mathematics to make a prediction, then apply the mathematics, and ultimately maybe change the use of mathematics if future observations do not fit the mathematics prediction. Its merely a tool (a very powerful one when properly used). Numerology, on the other hand, appears to me to assume that numbers themselves have some mystic or magical property, and that the numbers themselves confer on the object some property or quality.

I would also point out that the principles of mathematics work with any number system (base 2, base 10, Hexadecimal, etc). All the numerology I've seen seems to be limited to base 10.

In order to find a unique solution for each variable you must have as many different relationships as you have variables. The quadratic Equation works because there is only one variable (usually x, but doesn't have to be). If you have three variables in a single equation, such as you suggest, you can find an essentially infinite set of values that will solve the equation, but to find the unique solution you need three different equations all using the same three variables. That means there is no shortcut equation like the quadratic equation (the Quadratic equation is simply derived by the method called "Completing the Square" starting with the ax²+ bx + c = 0, a method that won;t work with multiple variables, unless of course you have multiple unique equations).

It's all OK guys-- remember, this is the internet. The great thing about the internet and computers is it lets us be brave enough to type things we wouldn't have the guts to say to someone face-to-face.

There are other aspects that (maybe) are in favor of Aircraft carriers. The Nuclear powered carriers do not have to carry fuel, which allows them to carry large amounts of fuel for both their aircraft AND other ships in their group-- which gives them added flexibility and range. They have been designed to withstand the blast of everything up to and including small tactical nucs-- such as nuclear torpedoes . It is also very, very difficult to punch a hole in the hull of a modern Aircraft carrier, and they don't have to worry much about being attacked by submarines. Unfortunately, I cannot give you any links to support this, as details are still classified, but I was there for a lot of the design work.

Things progress in a way to get better?? Didn't work for the Dinosaurs, and I wouldn't count on it for us either.

A related topic if you want to look it up is Kohlberg's stages of Moral Development. He basically postulated six stages, starting with total ego-centricity (young children) through the final stage where people recognize that there are moral absolutes that apply even without laws. If I recall correctly, he also postulated that not all adults make it to the last stage. I don't have a non-copyrighted link to offer, but I believe wikipedia probably would be a place to start.

OK-- I have to ask. Let's postulate that "A" is the one that lies, and B is the one who tells the truth. If I ask "A" "If you were your brother (sister) would you always tell the truth?", the correct answer would be that B tells the truth, so "A" will lie and say say "No." If I ask B "if you were your brother (sister) would you tell the truth?", the correct answer would be "No", and that is the answer B would give, because B always tells the truth. Since both will answer "No", how can I meet the original challenge of telling which is which??

My wife an I do not permit news programs in our home (and we never have done so). Way too much sensationalism and depressing. Instead, we read. We wait awhile for the news to make it into print-- which usually allows for the really important stuff to rise to the surface.

Velocity-Boy: "You don't get half a card from each stack for one trait."

I agree with your point, but your statement isn't quite correct. You receive one full allele from each parent. Those two alleles, depending on the mix of dominance and or recessiveness (and even more complicated for polygenic traits) then determines the resulting phenotype. Thus, for each trait in the offspring there really is one- half from each parent. What I think you were trying to point out is that the expressed trait (the phenotype) will not be an average of the two contributions, with which I fully agree.

I find the idea that we do not possess free will ludicrous. The thoughts I develop and the actions I take originated somewhere in my brain. Whether I consciously thought about it or whether it emerged from some dim back corner without conscious thought or whether or not someone convinced me to do it is immaterial.-- either way the decision to act came from within. That's free will.

Environment, not socialization. Survival in the environment is the ultimate decider as to who survives, hence what brain capability survives. Pardon my pessimism, but as I look at modern society I have trouble believing that typical social interactions could in any way be correlated to improved encephalization.

I too believe that when you are dead you are dead-- there is no afterlife. However, I maintain that Heaven and Hell do exist and most of us will eventually face them. Most of us will sooner or later in our life evaluate who we are and what we have done. Heaven is within the mind-- being satisfied that we did our best and have loved ones and friends. Hell is also within the mind-- knowing we screwed up and that its too late to fix.

I would say applied math in some form is a must. I took lots of physics and chemistry-- which makes sense since I took degrees in Chemical Engineering and Nuclear Engineering. But-- in the end, you're going to need a strong base in practical math in order to make use of the Physics, and Chemistry. Even Biology has a surprising amount of math if you really want to investigate and correlate information. There were many, many times in my career (I'm retired now) when I needed math as much or more than the chemistry and physics, simply because i needed a result I could apply that was properly developed from the theory.

Lots of good advice. In the end-- as cruel as I know this will sound, you have to let the deniers fail/die/or suffer whatever consequences their bad decision brings about. We live in a very protected age. Everything has operating warnings. We have medical miracles. Many, many people, either consciously or unconsciously don't really believe their actions or decisions will have serious consequences. Someone or something will save them no matter how stupidly they may behave. Some people will only change when they have concrete personal proof that they are/were wrong. Cruel, but. I fear, true.

With no real basis, I have often wondered if Deja Vu might simply be a memory timing issue. We have short term memory and long term memory. If somehow an experience slips into long term memory faster than it arrives in short-term, might we believe we have had this experience before??

Very true, but I enjoy playing with the chemical side (probably not surprising for a Chemical Engineer).

Yes, you need to be concerned about molds. But-- if your walls are made of wall-board the standard for many years has been to use a special type of wallboard in kitchens and bathrooms that is mold and moisture resistant. You just want to make sure the paint has good coverage and let the walls dry after each use (I've got a shower in my house that has walls with one original coat of paint, applied in 1991 over mold resistant wallboard, and not a spec of mold yet).

I realize this is an old post-- but gunpowder and firearms design is a topic close to my heart so I thought I would add some ideas.

Certainly, a magnetic or other energy source approach to a firearm is within the reach of current technology. This prompts me to toss out some suggestions for the specifications such an alternate approach might want to meet. At a very early point in history firearms were revolutionary-- but since then the development of firearms has been evolutionary-- and there are lots of unique aspects that a new design might want to consider.

The energy source: Certainly, any energy source that cam impart sufficient velocity and momentum will do. Gunpowder is particularly well suited to this task. It is easily packaged in the cartridge which means no external power source has to be maintained. It lasts very long times without degradation (100year old ammunition usually works just fine). This gives it a degree of superiority over liquid fuels and external power sources.

The projectile: accuracy over a great distance usually requires stable flight and a minimum of velocity loss with distance. This prompts us to want low drag and high mass. Low drag to minimize energy losses and high mass to provide higher energy and momentum. Lead projectiles, although originally convenient because one could make their own musket balls over a fire, work particularly well (regardless of whether or not they are covered by a metal jacket) because lead is a very dense material-- allowing lots of mass in a small package with a small drag cross-section. Your design needs to think about the projectile, how far you want it to go and how much energy you want it to retain over that distance.

The launching mechanism: Unless your projectile can be controlled during flight, you need to give it not only linear momentum but also angular momentum about the axis of the direction of travel (spin). This is another reason lead has worked out so well-- it engraves to the rifling, which imparts spin, yet it (and copper jackets) are soft enough that they cause minimal wear to the barrel. And-- a rifled barrel is really a very simple means of imparting spin to a projectile. your design needs to consider how you will obtain stability in flight and how to do so in a way that will be reliable for extended use.

Energy impulse: The time duration and peak of the energy impulse has a lot to do with the requisite strength of the launching mechanism. This actually makes something like a rail gun look pretty good, because the acceleration force can me modulated and maintained right up until the projectile leaves the mechanism. This is, in fact, how gunpowder systems work. There are currently about 150 different formulations of gun powder commercially available that have purposely designed burning rates ranging from very fast (essentially an explosion) to very slow (more like solid fueled rockets). This permits each cartridge to be designed such that the gunpowder burn will last until the projectile leaves the barrel and also allows the peak pressure of the burn to be matched to the capabilities of the firearm design.

Flexibility and ease of use: This relates to the hobby of reloading. Many people (myself included) reload our own ammunition because it allows us to customize the ballistics of our firearm for whatever purpose or interest we wish. We can tailor our charges for any velocity from barely enough to leave the barrel all the way to supersonic flight (within the pressure capability of the firearm). We can vary the composition, mass and shape of our projectile to suit our interests. Some of us (particularly old engineers) can waste thousands of rounds of ammunition doing nothing be experiment with the variables. The equipment needed is simple and inexpensive. This is why reloading is such a popular hobby even though factory made ammunition is readily available-- the factory loads are very standardized and not customized to a particular firearm and its mechanical tolerances. So-- if you want to design a good replacement for gunpowder firearms, think about whether or not you design will be within the reach of people to tinker and play with.

(for those wondering what I do with all this-- I plan to someday have a perfect set of custom loads for each of my 5 rifles-- just for target shooting, since I am not a hunter. So far I've only built and fired about 18,000 rounds, but I still have so very many experiments I still want to try).

"Unsurprisingly" is quite correct. The speed of oxidation with Potassium Permanganate, IIRC, depends on the presence of a medium for the reaction to take place in. Very slow in this case presumably because the tissue was dry. I used to demonstrate this to my Chemistry students by mixing a few grams of Potassium Permanganate with a few grams of skin moisturizer in a small plastic cup. Nothing happens for the first minute or so, and then it burns very hot and very quickly (like a highway flare), consuming the moisturizer and the plastic cup.