tinkerer

"My preferred one is liquid hydrogen at 1atm with vacuum insulation. " Please explain how hydrogen may be kept liquid at 1 atm. pressure?

In my own case, I had been very active during my teens and early twenties engaged in building fast cars. High school included Biology, Physics, Pl. Geom., Alg. I & II, Chem., Trig., and several shop courses. As a necessity, I became quite proficient in many skilled trades working on the cars. Thus, when I started college aiming at Engineering, I had a very good ability to perform skilled work and a foundation for the more theoretical Engineering topics. I could have secured employ as a Machinist, Pipefitter, Welder, or the like, but felt I never would be satisfied earning a living thusly. Marriage did not interfere; I took night courses in Physics and Chemistry, went on to enroll at age 31 at the University of Nevada, Las Vegas, in Engineering, full time. I received my B.S. Engineering at age 34. It can be done. Winding up supervising a team of skilled maintenance workers in a manufacturing plant confirmed the universal disdain the skilled have for Engineers.......until they learned I could often out-perform them!

As a Sophomore in high school, a rotary high-voltage interruptor I had built myself to copy one of Strickfadden's similar devices in a Frankenstein movie was used to build an operating high-voltage high-frequency Tesla coil. I could not enter the Science Fair as I was not in General Science, but my friend took it over and won second place! Just reminiscing, sorry.

I enjoyed the simple way you presented that! For me, it's a matter of air being a compressible fluid, and when compressed such that it experiences pressure greater than atmospheric pressure, it has the ability to move, to flow, attempting to relieve that pressure. Squeezing air to make it move is a much more forgiving process than doing so with a liquid, which is for most practical considerations, incompressible. However that fact may be, even metals can be compressed if subjected to extremely high stresses. If this copies, here is a chunk of metal being compressed under millions of pounds per square inch, the event copied by extremely high-speed X-Ray images:

Many years ago, as a kid, we heard about the "goodness" present in Sunlight, that is, UV. UV lamps were sold specifically to be placed in the rooms of infants to "cleanse" the air. Window glass was marketed with the quality of transmitting far more UV than normal glass: it was called "Vitaglas", possibly with two "s"es. I have searched in vain for reference to Vitaglas.

Celluloid is made of nitrocellulose and camphor. Nitrocellulose is the basis for almost all Smokeless Propellants, smokeless powder in vernacular. We made nitrocellulose out of thin paper and used it as magicians do with their "touch paper"; ignited, it burns completely emitting no smoke, and leaving virtually no ash. Some of the nitrated esters also burn completely, a different kind of "burning", actually a dissociation of the molecules into the component elements contained. One would be Propanetriol.

One of my instructors long ago suggested that in understanding an electron's dropping down to a higher energy level, which results in ejection of a photon, think of light emission as being caused by "successive suck-ins". One never forgets such an illustrious explanation.

Fascinating! Recently, I looked up the theory of Magnetron operation, as I had studied it in the early '60s as a Technical School student. The poles, basically axial keyholes in the I.D. of a cylindrical chunk of conductive non-ferrous material, copper commonly I think, form a tuned resonant circuit in which the pole faces form the capacitive plates, the poles the inductor. To me, simple-minded, this concept seems to border on original design madness. Yet, it works quite well.

@Strange RE: "A magnetic field is generated by a changing electric current." This would imply that no magnetic field exists around a conductor carrying a constant direct current. Is that so? My Electric Theory course in Freshman High School provided an experiment in which powdered iron arranged itself allowing us to "see" magnetic lines of force about a current carrying conductor. On board ship, my co-worker, ex-Navy, told of D.C. welding cables lying on the steel hull doing all sorts of dances at times.

"Seawater contains very few metal ions. "This leads me to wonder: The two commonly considered water "hardness" elements are Calcium and Magnesium. Both are thought of as metals. Both are present in virtually all water present naturally upon this planet. Both contribute to the factor arbitrarily called "water hardness". Therefore, the statement regarding Seawater containing very few meta lions, seems misdirected, at best. However, what is your point, Grandma? Obviously seawater is highly ionized, but so what?

An experience greatly unexpected, to be sure, and gravely disruptive within our little family. My wife had a brother, then 16, and sister, 11, both of whom were left homeless with the only other relatives present in America being my wife and I. Certainly most curious result was the fact that during that period, I had been called up for Armed Forces Induction, the Viet Nam conflict at it's height. Having officially become responsible for two minor children, I appeared before the Local Draft Board in our town's Post Office basement. When asked to describe circumstances, upon hearing "murder-suicide", one lady gasped, recalling the event had taken place just across the street! Almost instantly, my father in law's maniacal act had quite possibly saved my life!

Acetylene gas is stored in steel tanks in fashion similar to your description. It is absorbed by an inner material, carbon, I believe, possibly saturated with acetone, but I forget where I heard that. Typical pressure encountered with usual surrounding temperatures is several hundred pounds per square inch. I have always heard it is stored thusly for purposes of safety, but never understood the issue. I expect @John Cuthber has greater knowledge of this than I, and perhaps he will share. Interesting to note here that it is common practice in industry (at least here in the States) to use liquid propane fed directly in that form to the engines of fork-lift trucks. Perhaps delivery volume is inadequate in gas form, made even worse by the cooling effect on the tank of gas leaving it, which lowers the pressure. Such operation would likely be unstable. Delivering liquid ensures fairly constant pressure, so long as surrounding temperature remains relatively constant. IMHO, a glut of gasoline will present itself should a fairly rapid transition, say, changeover for a following model-year occurs, making it the predominating fuel. However, gasoline prices are highly variable, and quite manipulable. I should think if considerable differences exist regarding exhaust emissions between liquid fuel and gaseous, that will affect the result. Hydrogen usage, of course, is most preferable in that respect. Personally, I've witnessed too many hydrogen explosions to yet become comfortable with it's general use. Ask the Germans!

Correct. However, the concern is that if the liquid will not BOIL, no pressure to deliver it is readily available. IOW, "Butane boils at -0.5°C so when the ambient temperature falls to around freezing no gas is produced and even at around +4°C the pressure is too low to be useful. Propane boils at -42°C so can be used in arctic conditions.

Not to feel badly; it was not until I was in my 60s that I learned the veins returning blood from lower extremities are surrounded by tiny muscle structures which contract one following another, as the heart brings blood back upwards, against gravity. They act in effect as check valves, holding the blood between them when the diastolic (resting) part of the pulse presides, preventing a coursing up and down of the contents. Truly amazing!

Our plant in Indiana used Propane in winter when natural gas supplies were curtailed. Two 30,000 gallon tanks of it. A sudden "cold snap" resulted in a noticeable slow-down of the boilers' output, then cessation. Determined the "propane" was freezing in piping connecting the tanks to the plant building. Subsequent investigation determined that the LPG supplier routinely blended BUTANE with the PROPANE, as it was less expensive. The customer normally never knew........until his pipes froze with the much higher freezing-point butane! 30 degrees F.

Interestingly, a typical home-designed Tesla Coil uses 60 HZ as it's primary frequency, usually at reasonably high voltage, 10kv to 15kv using a commercially available neon lighting or ignition transformer which passes it's current through a primary coil having but few turns, and being interrupted by a spark gap in series. This alternate 60 HZ "nudging" of the primary circuit starts, and maintains, "ringing" or resonance in the secondary coil which is connected in parallel with appropriate capacitance. The degree of "step-up" may be hundreds to one, or more. Thus a million volt presence may be obtained via the secondary, whose values of Inductance and Capacitance are such that the resonant frequency may be hundreds of times the primary circuit frequency. (whew!)

Was the question not the opposite? You describe how gravity is overcome returning the blood upwards back towards the heart. The question was how does blood travel from the heart to the feet. Try hanging upside down for some protracted length of time to see how uncomfortably the heart then struggles to overcome gravity getting blood flow to the feet.

My optimism was subverted when my new wife's father shot and killed her mother, then taking his own life. She (my wife) was 20, I was 25. Optimism shattered.

So true. Steering magnets are a new term to me; however, I do recall the smaller CRTs, such as used for oscilloscopes used charged deflection plates, vertical and horizontal, mounted within the envelope. Large CRTs such as TV used electromagnetic deflection via coils surrounding the CRT neck. Those were called "sine coils", for reasons I never learned.

The device is known colloquially as a "Jake Brake". I heard valve timing was involved, but never delved into exactly how that was accomplished. Truck diesel engines in general have quite husky valve train parts, and I do know that in some designs, "engine runaway" upon attempting shut-down was thwarted by locking the exhaust valves open.

Of course they were explained, but not adequately to a bunch of ruffian young men drawn from every imaginable walk of young adulthood, farmers, recent high school grads (like me), recent military dischargees. The Degaussing magnet I would have to search, today easily done. Thanks for your response.

My point here regarding electron movement within a highly evacuated space is that when I studied and attempted to assimilate it, much less understanding beyond the very basics existed (1962 or so). We had magnets glued to the necks of CRTs which were "Degaussing" devices, for example. No instructors back then explained their theoretical function. But we did greatly enjoy drawing arcs of high-voltage high-frequency origin off of the Horizontal Output Tubes!

What might you imagine such meters to be then? Off the shelf ten-dollar priced devices capable of measuring H+ ion content?

I have and use such devices, and have forever and a day wondered about "Soil Ph". Rather still "up in the air", though.

Evidently, to me at any rate, ions seem to exist differently on opposing sides of the "pond"......