MECHANICAL ADVANTAGE - Mechanical advantage (MA) is the factor by which a machine multiplies the force put into it. Consider lifting a weight with rope and pulleys. A rope looped through a pulley attached to a fixed spot and attached to the weight is called a single fixed pulley. It has a MA = 1, meaning no mechanical advantage (or disadvantage) however advantageous the change in direction may be. A single moveable pulley has a Mechanical Advantage = 2. Consider a pulley attached to a weight being lifted. A rope passes around it, with one end attached to a fixed point above, e.g. a barn roof rafter, and a pulling force is applied upward to the other end with the two lengths parallel. In this situation the distance the lifter must pull the rope becomes twice the distance the weight travels, allowing the force applied to be halved. If an additional pulley is used to change the direction of the rope, e.g. the person doing the work wants to stand on the ground instead of on a rafter, the mechanical advantage is not increased. By looping more ropes around more pulleys, we can continue to increase the mechanical advantage. If we have two pulleys attached to the rafter, two pulleys attached to the weight, one end attached to the rafter, and someone standing on the rafter pulling the rope, we have a mechanical advantage of four. If we add another pulley so that someone may stand on the ground and pull down, we still have a mechanical advantage of four.

............................................................................................................................................

Mechanical Advantage

What is Mechanical Advantage

EDinformatics.com

In physics and engineering, mechanical advantage (MA) is the factor by which a machine multiplies the force put into it.

The mechanical advantage can be calculated for the following simple machines by using the following formulas:

·      Lever: MA = length of effort arm ÷ length of resistance arm. 

·      Wheel and axle: A wheel is essentially a lever with one arm the distance between the axle and the outer point of the wheel, and the other the radius of the axle.

Typically, this is a fairly large difference, leading to a proportionately large mechanical advantage.

This allows even simple wheels with wooden axles running in wooden blocks to still turn freely, because their friction is overwhelmed by the rotational force of the wheel multiplied by the mechanical advantage. 

·      Pulley: Pulleys change the direction of a tension force on a flexible material, e.g. a rope or cable.

In addition, pulleys can be "added together" to create mechanical advantage, by having the flexible material looped over several pulleys in turn.

More loops and pulleys increase the mechanical advantage. 

Mechanical advantage

Consider lifting a weight with rope and pulleys.

A rope looped through a pulley attached to a fixed spot, e.g. a barn roof rafter, and attached to the weight is called a single fixed pulley.

It has a MA = 1, meaning no mechanical advantage (or disadvantage) however advantageous the change in direction may be.

A single moveable pulley has a Mechanical Advantage = 2. Consider a pulley attached to a weight being lifted.

A rope passes around it, with one end attached to a fixed point above, e.g. a barn roof rafter, and a pulling force is applied upward to the other end with the two lengths parallel.

In this situation the distance the lifter must pull the rope becomes twice the distance the weight travels, allowing the force applied to be halved.

Note: if an additional pulley is used to change the direction of the rope, e.g. the person doing the work wants to stand on the ground instead of on a rafter, the mechanical advantage is not increased.

By looping more ropes around more pulleys, we can continue to increase the mechanical advantage.

For example, if we have two pulleys attached to the rafter, two pulleys attached to the weight, one end attached to the rafter, and someone standing on the rafter pulling the rope, we have a mechanical advantage of four.

Again note: if we add another pulley so that someone may stand on the ground and pull down, we still have a mechanical advantage of four.

Here are examples where the fixed point is not obvious:

A man sits on seat that hangs from a rope that is looped through a pulley attached to a roof rafter above. The man pulls down on the rope to lift himself and the seat.

The pulley is considered a movable pulley and the man and the seat are considered as fixed points; MA = 2.

A velcro strap on a shoe passes through a slot and folds over on itself. The slot is a movable pulley and the Mechanical Advantage =2.

Two ropes laid down a ramp attached to a raised platform. A barrel is rolled onto the ropes and the ropes are passed over the barrel and handed to two workers at the top of the ramp.

The workers pull the ropes together to get the barrel to the top. The barrel is a movable pulley and the MA = 2.

If the there is enough friction where the rope is pinched between the barrel and the ramp, the pinch point becomes the attachment point.

This is considered a fixed attachment point because the rope above the barrel does not move relative to the ramp.

Alternatively, the ends of the rope can be attached to the platform.

·      Inclined plane: MA = length of slope ÷ height of slope 

Generally, the mechanical advantage is calculated thus:

·      MA = (the distance over which force is applied) ÷ (the distance over which the load is moved) 

also, the Force exerted IN to the machine × the distance moved IN will always be equal to the force exerted OUT of the machine × the distance moved OUT.

For example; using a block and tackle with 6 ropes, and a 600-pound load, the operator would be required to pull the rope 6 feet, and exert 100 pounds of force to lift the load 1 foot, therefore:

·      (force IN 100 × distance IN 6) = (force OUT 600 × distance OUT 1) 

·      or, WORKin = WORKout

This requires an ideal simple machine, meaning that there are no losses due to friction or elasticity. If friction or elasticity exist in the system efficiency will be lower; Work in will be greater than Workout

Mechanical advantage also applies to torque. A simple gearset is able to multiply torque.

Type of mechanical advantage

There are two types of mechanical advantage:

1.Ideal mechanical advantage (IMA) 

2.Actual mechanical advantage (AMA) 

Ideal mechanical advantage

The ideal mechanical advantage is the mechanical advantage of an ideal machine.

It is usually calculated using physics principles because we have no ideal machine. It is 'theoretical'.

The IMA of a machine can be found with the following formula:

IMA = DE / DR

where DE equals the effort distance and DR equals the resistance distance.

Actual mechanical advantage

The actual mechanical advantage is the mechanical advantage of a real machine.

Actual mechanical advantage takes into consideration real world factors such as energy lost in friction. In this way, it differs from the ideal mechanical advantage, which, is a sort of 'theoretical limit' to the efficiency.

The AMA of a machine is calculated with the following formula:

AMA = R / Eactual

where

R is the resistance force, 

Eactual is the actual effort force.

EDUCATION FOR THE INFORMATION AGE

https://www.edinformatics.com/math_science/simple_machines/mechanical_advantage.htm

REFINING A GOLD SMELT - Gold nuggets are not pure gold. They are a combination of minerals, known as ore. Gold can be removed from the ore in a process known as smelting, in which the minerals are separated by melting point. Smelt gold is more pure than the original ore, but can still contain impurities such as silver, copper and platinum. A second refinement can be done by dissolving the smelt gold in a method known as aqua regia refinement. The result is gold that is 99.95 percent pure. Weigh your gold smelt. For every ounce of gold, you will need a container with a 300-milliliter capacity. So, if you're refining 5 ounces of gold, you will need a 1500 milliliter container, or about 1 ½ quarts. Add 30 milliliters of nitric acid for every ounce of gold. So, if you're refining 5 ounces of gold, you would need to add 150 milliliters to the container. Allow the gold to sit in the nitric acid for 30 to 45 minutes. Add 120 milliliters of hydrochloric acid for every ounce of gold in the container. For 5 ounces of gold that would be 600 milliliters of HCL. The addition of hydrochloric acid turns the mixture brown and can result in fumes. As the chemicals react and heat up, the gold will dissolve. Let the mixture sit for 1 to 8 hours to cool off. Line the funnel with filter paper and pour the acid through the filter and into another, larger container, stopping before any particles are poured off. The filtered acid should be green and clear. If the acid is cloudy, filter it again. Boil 1 quart of water. Remove from heat and add 1 pound of urea. Slowly add the urea mixture to the acid. This will cause an acid/base reaction, much like the old school volcano using baking soda and vinegar.

.................................................................................................................................................

How to Refine a Gold Smelt

By Lisa Parris

In nature, gold nuggets are not pure gold. They are a combination of minerals, known as ore.

The metal can be removed from the ore in a process known as smelting, in which the minerals are separated by melting point.

Smelt gold is more pure than the original ore product, but can still contain impurities such as silver, copper and platinum.

A second refinement can be done by dissolving the smelt gold in a combination of acids; a method known as aqua regia refinement. The result is gold that is 99.95 percent pure.

Weigh your gold smelt. For every ounce of gold, you will need a container with a 300-milliliter capacity.

So, if you're refining 5 ounces of gold, you will need a 1500 milliliter container, or about 1 ½ quarts.

Add 30 milliliters of nitric acid for every ounce of gold. So, if you're refining 5 ounces of gold, you would need to add 150 milliliters to the container.

Allow the gold to sit in the nitric acid for 30 to 45 minutes.

Add 120 milliliters of hydrochloric acid for every ounce of gold in the container. For 5 ounces of gold that would be 600 milliliters of HCL.

The addition of hydrochloric acid turns the mixture brown and can result in fumes.

As the chemicals react and heat up, the gold will dissolve. Let the mixture sit for 1 to 8 hours to cool off.

Line the funnel with filter paper and pour the acid through the filter and into another, larger container, stopping before any particles are poured off.

The filtered acid should be green and clear. If the acid is cloudy, filter it again.

Boil 1 quart of water. Remove from heat and add 1 pound of urea.

Slowly add the urea mixture to the acid. This will cause an acid/base reaction, much like the old school volcano using baking soda and vinegar.

The acid will foam up, so don't pour too quickly or you'll have a huge mess on your hands.

When the mixture stops foaming, stop pouring urea in. All the nitric acid has been neutralized.

Boil a second quart of water. Remove it from the heat and stir in Storm. For every ounce of gold, add 1 ounce of Storm precipitant.

So, for 5 ounces of gold, add 5 ounces of Storm. (If using a different gold precipitant, follow the package directions).

Slowly stir this solution into the acid. The solution will turn a muddy brown color and emit a strong odor.

Wait 30 to 45 minutes. Check the acid for dissolved gold. To do this, take the end of the stirring rod and insert it into the acid.

Remove the rod and touch it to a paper towel, creating a wet spot.

Add one drop of gold detection liquid to the spot on the paper towel. If the spot turns dark, there is still gold in the acid. If you see this, give the Storm more time to work or add more precipitant to the acid.

When the acid has separated into layers, with a clear amber top and a muddy brown bottom, pour off the top layer into another container.

Be careful not to pour off any of the mud at the bottom as the mud is your gold.

Add water to the mud when the acid has been poured off. Stir vigorously and allow the mud to settle. Repeat, rinsing the mud with water 4 times.

Rinse the mud with aqua ammonia. When the aqua ammonia is added, white vapors will form as the remaining acids are neutralized.

Rinse the gold mud a final time using distilled water. When it settles, pour off the water and scrape the mud into a heat proof bowl.

Place the bowl on a hot plate and allow it to dry.

When the dry mud is melted and allowed to reform it will take on the appearance of metal and will be 99.95 percent pure.

Things You'll Need

Scale

Heavy duty plastic buckets

Wooden rod to stir with

Safety goggles

Rubber gloves

Rubber apron

Nitric acid

Hydrochloric Acid

Filter paper

Funnel

Water

Urea

Gold selective precipitant, such as Storm

Paper towels

Precious Metal Detection Liquid

Aqua ammonia

Distilled water

Heat proof bowl

Hot plate

Tips

If there was platinum in your gold, it will not be dissolved by the acids and will be left behind in step 4. Always save your precipitants- you never know what you may get.

Warnings

This method uses strong acids which can be harmful if spilled on the skin or if ingested. They also generate fumes which can irritate the respiratory system.

Work in a well-ventilated area and use protective clothing. Neutralize any acid spills with a liberal application of baking soda.

Lisa Parris is a writer and former features editor of "The Caldwell County News." Her work has also appeared in the "Journal of Comparative Parasitology," "The Monterey County Herald" and "The Richmond Daily News." In 2012, Parris was honored with awards from the Missouri Press Association for best feature story, best feature series and best humor series.

https://sciencing.com/refine-gold-smelt-4826998.html

ESP & PSYCHIC POWERS - The idea of special — apparently paranormal — mental abilities such as psychic powers or extrasensory perception (ESP) has intrigued people for centuries. There are several claimed varieties of psychic powers, including telekinesis (or psychokinesis, the ability to move objects through mind power); precognition (knowing future events before they happen); and telepathy or clairvoyance (French for "clear sight" — describing things at a remote location). Many Americans believe in psychic ability (about 15 percent of the country, according to a 2005 Baylor Religion Survey; and 41 percent in another survey), but scientific evidence for its existence remains elusive. And it's not for lack of trying; people — and the U.S. government — have spent decades searching for ESP. Though the government concluded that psychic power doesn't exist (or, if it does, the information it provides is no more accurate than random chance guesses), ESP research has continued. ESP has not fared well under scientific conditions, whether in the private or public sector. Early experiments used "Zener cards" with common symbols such as circles, squares, and wavy lines selected at random and which a psychic would try to guess. Overall the vast majority of ESP studies can best be characterized as inconclusive. Some studies suggest evidence of some sort of psychic ability; others don't.

............................................................................................................................................... 

Research has not proven that extra powers of the mind exist. 

ESP & Psychic Powers

Claims Inconclusive

By Benjamin Radford 

The idea of special — apparently paranormal — mental abilities such as psychic powers or extrasensory perception (ESP) has intrigued people for centuries.

There are several claimed varieties of psychic powers, including telekinesis (or psychokinesis, the ability to move objects through mind power); precognition (knowing future events before they happen); and telepathy or clairvoyance (French for "clear sight" — describing things at a remote location).

It's the stuff of fiction and movies — but is it real?

Many Americans believe in psychic ability (about 15 percent of the country, according to a 2005 Baylor Religion Survey; and 41 percent in another survey), but scientific evidence for its existence remains elusive.

And it's not for lack of trying; people — and the U.S. government — have spent decades searching for ESP.

Government ESP research

During the Cold War, rumors circulated that the Russians were developing an army of psychic spies; in response, the U.S. military created a program to examine whether psychics could be useful in military applications.

The program, called Stargate, tested "remote viewers" to see if their feelings and visions were accurate.

The research continued for about two decades, ending in the mid-1990s with little apparent success.

Finally, the CIA took over the program and asked scientists to review the results.

They concluded that the psychics did no better than chance, and that the psychic information was neither validated nor useful.

Project Stargate failed and was shut down. SOUND

Some suggest that the fact that Stargate program even existed is evidence that there must be some validity to psychic powers (otherwise it would not have been created and funded for years).

Yet countless programs have been funded despite never having been proven valid or effective; the U.S. government spending money on fruitless programs is hardly novel.

Some believe that top-secret government programs still use psychics today, though high-profile intelligence failures (i.e., if accurate psychics are employed by the government, why did it take a decade to find Osama bin Laden?) cast doubt on such conspiracy claims.

ESP in the laboratory

Though the government concluded that psychic power doesn't exist (or, if it does, the information it provides is no more accurate than random chance guesses), ESP research has continued.

Unfortunately, ESP has not fared well under scientific conditions, whether in the private or public sector.

Early experiments used "Zener cards" with common symbols such as circles, squares, and wavy lines selected at random and which a psychic would try to guess.

In the 1930s and 1940s a researcher at Duke University named J.B. Rhine became interested in the idea that people could affect the outcome of random events using their minds.

Rhine began with tests of dice rolls, asking subjects to try and influence the outcome through concentration.

Though his results were mixed and hardly robust, they were enough to convince him that there was something mysterious going on.

Unfortunately for Rhine his experiments failed a crucial scientific test, that of replicability: other researchers were unable to duplicate his findings.

Errors were found in his methodology, and the topic faded away.

By the 1960s, computer technology allowed more sophisticated tests, including using psychic powers to influence the outcome of random number generators.

In 1976, several children who claimed to be able to bend spoons with their minds were tested in controlled experiments at the University of Bath.

For a while the results seemed promising, and experimenters believed they might finally have found real scientific evidence of psychokinesis.

Unfortunately, the children were caught cheating on hidden cameras, physically bending spoons with their hands — not their minds — when they thought no one was watching.

Inconclusive results

The problem is not that skeptics and scientists refuse to take ESP seriously; indeed, researchers have spent decades trying to find good evidence.

One famous research organization, the Princeton Engineering Anomalies Research group, led by Prof. Robert Jahn, spent nearly three decades searching for psychic ability, usually getting mixed and inconclusive results.

It finally closed its doors in 2007, never having found hard scientific evidence for ESP.

Still, others continue the research.

An emeritus professor at Cornell University, Daryl Bem, spent much of the past decade conducting experiments that he believes demonstrate that psychic powers exist.

Bem tested the ability of college students to accurately sense random events, such as detecting where an image will flash on a computer screen. Bem's research was published in "The Journal of Personality and Social Psychology," a respected psychology journal.

The study made national news, but researchers who examined Bem's studies found significant statistical and methodological flaws, suggesting that his apparent success was likely an artifact of those errors.

Bem stood by his findings, acknowledging some mistakes and dismissing others, and encouraged others to replicate his ESP studies.

If he had really found scientific evidence for psychic ability, others should be able to duplicate it.

Two different teams of independent researchers replicated Bem's research — and both failed to find any evidence for ESP.

The studies were published in the journals "PLoS ONE" in 2011 and in the "Journal of Personality and Social Psychology" in 2012.

Overall the vast majority of ESP studies can best be characterized as inconclusive. Some studies suggest evidence of some sort of psychic ability; others don't.

Often the effect sizes were statistically significant but very small — not much above random chance.

Most of the studies that do show an effect (like Daryl Bem's) were never able to be replicated.

Ironically, if the ESP researchers are right and psychic ability does exist, it seems to be a very weak effect.

What's the point of using psychics if their guesses aren't much more accurate than the average person's?

Presumably the whole point of ESP is that it should be much more accurate and valid than chance or an informed guess — except that it isn't.

Those who believe in ESP are undeterred by the consistent lack of good evidence, and insist that one day scientists will find hard evidence of psychic abilities.

That may be true, but ESP believers said the same thing half a century ago.

Benjamin Radford is deputy editor of "Skeptical Inquirer" science magazine and author of six books, including "Scientific Paranormal Investigation: How to Solve Unexplained Mysteries." His website is www.BenjaminRadford.com.

For the science geek in everyone, Live Science breaks down the stories behind the most interesting news and photos on the Internet, while also digging up fascinating discoveries that hit on a broad range of fields, from dinosaurs and archaeology to wacky physics and astronomy to health and human behavior. If you want to learn something interesting every day, Live Science is the place for you.

https://www.livescience.com/23852-esp-psychic-powers.html