*HELIUM FACTS Atomic number* 2
*Atomic mass* 4.00260 g.mol -1 *Electronegativity according to Pauling* unknown *Density* 0.178*10 -3 g.cm -3 at 20 °C *Melting point* - 272.2 (26 atm) °C *Boiling point* - 268.9 °C *Vanderwaals radius* 0.118 nm *Ionic radius* unknown *Isotopes* 2 *Electronic shell* 1s 2 *Energy of first ionisation* 2372 kJ.mol -1 *Discovered by* Sir Ramsey in 1895 *Helium* *Properties* Gaseous chemical element, symbol: He, atomic number: 2 and atomic weight 4,0026 g/mol. Helium is one of the noble gases of group O in the periodic table <https://www.lenntech.com/periodic-chart.htm>. It’s the second lightest element. The main helium source in the world is a series of fields of natural gas in the United States. Helium is a colourless, odourless, insipid and non-toxic gas. It’s less soluble in water than any other gas. It’s the less reactive element and doesn’t essentially form chemical compounds. The density and viscosity of helium vapour are very low. The thermic conductivity and the caloric content are exceptionally high. Helium can be liquefied, but its condensation temperature is the lowest among all the known substances. *Applications* Helium has many unique properties: low boiling point, low density, low solubility, high thermal conductivity and inertness, so it is use for any application which can explioit these properties. Helium was the first gas used for filling balloons and dirigibles. This application goes on in altitude research and for meteorological balloons. The main use of helium is as an inert protection gas in autogenous welding. Its biggest potential is found in applications at very low temperatures. Helium is the only cooler which is capable of reaching temperatures lower than 15 K (-434ºF). The main application of ultralow temperature is in the development of the superconductivity state, in which the resistance to the electricity flux is almost zero. Other applications are its use as pressurizing gas in liquid propellants for rockets, in helium-oxygen <https://www.lenntech.com/Periodic-chart-elements/O-en.htm> mixtures for divers, as working fluid in nuclear reactors cooled down by gas and as gas carrier in chemical analysis by gas chromatography. *Helium in the environment* Helium is the second most abundant element in the known universe, after hydrogen. Helium constitutes the 23% of all elemental matter measured by mass. Helium is formed in The Earth by natural radioactive decay of heavier elements. Most of this helium migrates to the surface and enters the atmosphere. It could be logical to think that the helium concentration in the atmosphere was higher than it is (5,25 parts per million at sea level). Nevertheless, its low molecular weight allows it to escape to space at the same rate of its formation. There is an about 1000 km layer in the heterosphere at 600 miles where helium is the dominant gas (although the total pressure is very low). Natural gases contain higher helium concentrations than the atmosphere. Helium is the 71st most abundant element in the Earth's crust where it is found in 8 parts per billion (109). *Health effects of helium* *Effects of exposure: *The substance can be absorbed into the body by inhalation. Inhalation: High voice. Dizziness. Dullness. Headache. Suffocation. Skin: on contact with liquid: frostbite. Eyes: on contact with liquid: frostbite. Inhalation risk: On loss of containment this gas can cause suffocation by lowering the oxygen content of the air in confined areas. Check oxygen content before entering area. Neutral helium at standard conditions is non-toxic, plays no biological role and is found in trace amounts in human blood. KR IRS 13 8 23 On Sun, 13 Aug 2023 at 19:31, 'gopala krishnan' via iyer123 < [email protected]> wrote: > *CULTURAL QA 08-2023-13A* > > Q1 Where do cruise liners throw their wastewater? > > A1 Rebecca Williams, knows about boats and ships18h > > *Wastewater is the term used to describe any water that is used on a > cruise ship, such as water from toilets, sinks, showers, laundry, pools, > spas, and medical facilities*. > > Wastewater can be divided into two main categories: sewage and gray water. > > *Sewage is wastewater that contains human waste* and other organic > matter. > > Gray water is wastewater that does not contain human waste but may still > have contaminants such as soap, detergent, food particles, oil, and grease. > > *Cruise liners have different ways of disposing of* their wastewater, > depending on the type of water, the location of the ship, and the > environmental regulations that apply. > > The most common option for cruise liners is to discharge their wastewater > into the ocean. > > *However, they must follow certain rules and standards when doing so*. > For example, according to the Cruise Lines International Association > (CLIA), members agree to process all sewage through a sewage treatment > system that is certified in accordance with international regulations, > prior to discharge. > > They also agree to discharge sewage only when the ship is more than three > nautical miles from shore unless they have an advanced wastewater > treatment system that meets higher standards. > > *Gray water can be discharged at any distance from shore, as long as it > does not contain harmful substances or pose a threat to human health or the > environment.* > > Another option for cruise liners is to dispose of their wastewater at a > port that has the facilities and capacity to receive it. This option is > especially used when cruise liners are in areas where ocean discharge is > prohibited or restricted. For example, in some parts of Alaska, > California, and New England, there are no-dumping zones where cruise liners > cannot discharge any wastewater into the ocean. In these cases, cruise > liners must store their wastewater onboard and dispose of it at a port that > can handle it. > > Q2 How many miles will an average truck driver drive per day? How > do they stay alert? > > A2 Erika Fernandez, Car Lover3h > > According to the Federal Motor Carrier Safety Administration (FMCSA), a > truck driver can drive for a maximum of 11 hours in a 24-hour period, > after taking 10 hours off duty. > > This means that a truck driver can be on duty for a total of 14 hours, but > only 11 of those hours can be spent driving . The remaining 3 hours can > be used for loading, unloading, fueling, inspecting, or resting. > > The FMCSA also limits the number of driving hours and miles per week. *A > truck driver can drive for either 60 hours in 7 consecutive days or 70 > hours in 8 consecutive days. *To reset the weekly limit, the truck driver > has to take at least 34 consecutive hours off duty. This is known as the > 34-hour restart rule. > > Based on these rules, an average truck driver can drive about 55 to 60 > miles per hour, depending on the traffic, weather, and route conditions. *This > means that most truck drivers can drive around 605 to 650 miles per working > day*. > > However, this number may vary depending on the type of truck, the cargo, > the terrain, and the driver’s experience and preference. > > Driving for long hours and miles can be exhausting and dangerous for truck > drivers. They have to deal with various challenges and risks on the road, > such as fatigue, boredom, isolation, stress, distractions, accidents, and > weather hazards. > > To stay alert and safe on the road, truck drivers use various techniques > and tools, such as: > > Taking regular breaks and naps. The FMCSA requires truck drivers to take > a 30-minute break after driving for 8 consecutive hours. Truck drivers can > also take short naps during their breaks or off-duty time to refresh their > minds and bodies. > > Eating healthy and balanced meals and snacks. Truck drivers need to > maintain their energy levels and avoid dehydration and hunger. They can eat > nutritious foods that are rich in protein, fiber, vitamins, and minerals, > such as fruits, vegetables, nuts, eggs, cheese, yogurt, and lean meat. They > should also drink plenty of water and avoid alcohol, caffeine, sugar, and > junk food. > > Listening to music, podcasts, audiobooks, or radio. Truck drivers can use > audio entertainment to keep their minds stimulated and engaged while > driving. They can listen to music that suits their mood and preference, or > podcasts and audiobooks that interest them or teach them something new. > They can also listen to radio stations that provide news, weather updates, > traffic reports, or sports commentary. > > Q3 What's the use of the "tiny wings" on aircraft engines? And > why are they pointing downwards? > > A3 Jagrata Banerjee, Studied Aviation Updated 2y > > Nice observation !!! > > All modern commercial aircraft have these “tiny wings” attached on the > side of the engine cowling, somewhat near the engine pylon. *These are > known as Nacelle Chines/Strakes.* > > What is the cause of using the nacelle strakes ?? > > The nacelle chines are specially fitted on those airplane engines, *which > are mounted under the wings of the aircraft. What actually happens is when > the aircraft rotates or pitches up during takeoff, the huge engines block > some of the airflow, thus preventing them to reach the wing*. This causes > less air to flow over the wing. > > And also, during pitching up, the wing approaches the critical angle of > attack. With less airflow over the wing the wing approaches the critical > angle of attack, the wing might lose lift and eventually stall. > > *To prevent this kind of situation, the Nacelle Strakes are used*. The > way the nacelle strakes work is when the airflow approaches the wing and > the engines, these nacelle strakes *REDIRECT the boundary airflow over > the engines to flow over the wing.* > > They actually re-energize the oncoming airflow, thus creating an energized > vortex to flow over the wing, thus generating lift. This compensates for > the loss of airflow, earlier created by the engines. > > Why the nacelle strakes are pointed downwards? > > *The nacelle strakes are pointed downwards, so as to redirect the > energized vortex to the upper surface, that is, to the upper surface of the > wing.* > > Disadvantage of the nacelle strakes: Since, they are only needed when the > aircraft operates at high angles of attack, it is not used during cruise > flight. Thus, it creates an unnecessary aerodynamic drag (though very > little) in cruise flight. > > Q4 Is helium hard to make? How expensive is the process? > > A4 Geoffrey Widdison, Been learning science since I was six, > still getting started. Tue > > Make? > > *Yes, very hard. You need a nuclear reactor to do so.* > > Helium is an element, so to produce it, you either need larger atoms to > undergo nuclear decay and produce it as a by product, or hydrogen atoms to > fuse together. > > Either way, a ton of energy would be produced, but only a small amount of > helium. Producing useful amounts of helium by either process is unlikely > in the forseeable future. > > Lucky for us, some of those nuclear reactions happen naturally, within the > crust of the earth, and have for untold millions of years. Over that > timescale, those comparative trickles of helium make for pretty large > amounts. Most of that just leaked into the atmosphere, and most of that > escaped into space. But some of it got trapped in deposits in the rocks. > > Now, deposits of helium are never pure. In fact, at best, they’re only a > few percent of the gasses in there. Helium separation started when a > series of natural gas deposits along the Oklahoma-Texas border turned out > to have unusually high helium concentrations (something like 8%). That > was enough to create problems, so they built facilities to separate the > helium and throw it away. Over time, they realized that helium had some > useful properties, *and it began to be used for a number of purposes. > Eventually, they started deliberately looking for gas deposits with high > helium concentrations, so they could produce more helium*. > > Then, in 1925, the US government created a strategic reserve of helium, > because it was believed that the helium supply was potentially important > for national security. The reserve has since been privatized. > > The point, though, is that helium is effectively a non-renewable natural > resources. How expensive it is has something to do with how expensive it is > to extract, but also with availability of the resource itself, which is > often beyond our control. > > The process for separating helium from natural gas is a well-established > industrial process. Not something the average person could do in their > kitchen, but hardly outside the norm of large-scale manufacturing. Finding > helium, on the other hand, is rather trickier. > > Q5 A passenger arrives early with no checked bags for their > flight and wants to go on an earlier flight where there are available > seats. Why do many airlines not let them get on the flight without a fee? > > A5 Mitch Stevenson,Lives in Sydney, Australia11h > > *In Australia. One of the 2 main airlines (Virgin* Australia) have this > as a stated policy. *It works well if there's a seat on the earlier > flight.* > > *To get it though*. You need to be one of their top tier platinum flyers. > Also, I generally fly in business class and there's rarely business seats > left available at the last minute. So if you don't mind downgrading to > economy it's fine. > > *If I had to get somewhere urgently, then go for it.* But if it's only a > small wait of a couple of hours. I'll wait for my booked flight and enjoy > the lounge a bit further. > > *All the above QA are from Quora digest to me on 13-08- 2023.* > > *Quora answers need not be 100% correct answers .* > > *Compiled **and posted by R. Gopala krishnan, on 13-08-2023* > > > > -- > You received this message because you are subscribed to the Google Groups > "iyer123" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/iyer123/1437851349.2387485.1691935295264%40mail.yahoo.com > <https://groups.google.com/d/msgid/iyer123/1437851349.2387485.1691935295264%40mail.yahoo.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Thatha_Patty" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/thatha_patty/CAL5XZoqBg%3D%3DNiGJnkPDhMxzsxjjzpTB%3DjeMJ4dTsPqvt%2BWBWVg%40mail.gmail.com.
