Thursday, May 19, 2022
Wednesday, May 18, 2022
Wednesday, May 11, 2022
PROOF/EDIT Why are Planes Usually Painted White?
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Advantages of painting aircraft?
If you look carefully at non-military airplanes such as a commercial airplane, you will notice that most are painted white. Ever wondered why airplane companies use white airplane painting usually? Two reasons for this are: the white color helps to cool the aircraft and protects the plane from excessive heat by reflecting sunlight. Let’s see the other reasons that will surprise you.
Have you ever wondered why most non-military planes especially commercial one are painted white? There are exceptions, some airlines like the South African carrier mango tend to be bright orange or the Siberian S7 fleet are famously painted lime green. But the best majority of other planes are nearly always colored white or have a color scheme that is predominantly white. Is is just a coincidence or is there actually a scientific reason?
Advantages of painting aircraft?
Is there actually a reason to paint them at all? After all paints adds a lot of extra weight to an aircraft. Which in turn means more fuel is burned. However apart from being able to identify a particular operator from one another there are actually some very sound reasons to paint aircraft in the first place.
Many early aircraft especially those prior to world war 2 were usually left completely bare. In modern times the former American Airlines also famously had a largely bare aluminum exterior. This strategy is something of a false economy while it does save precious cash from some manufacturing maintenance and fuel expenses. It will cost the operator over time. The main reason is that it leaves the aircraft’s fuselage exposed and unprotected. Over time this tends to cause the plane to tarnish, attracting the frequent need to polish the exterior.
Painting a plane also helps improve the craft structural integrity. And makes it easier to clean and maintain in the long term. So painting an aircraft seems to be a good idea. But why choose white?
Why are planes usually painted white?
The first reason planes tend to be painted white is, as you might have guessed purely economical. White paint is cheap. Painting an aircraft is a very expensive affair. The process of painting an entire commercial airliner can cost anywhere between fifty thousand and two hundred thousand dollars depending on the size of the craft. The simpler and plainer the design, the lower the cost overall. If you factor in the lifelong maintenance costs of repainting an aircraft when needed. This can lead to a considerable overhead for the carrier. With white paint being relatively cheap and easily available choosing a primarily white scheme will save a lot of money over the planes service life.
Many carriers also sell their planes to other carriers which would require an expensive new paint job. If the plane were painted in a distinctive color like bright orange. By choosing more neutral paint schemes it increases the likelihood of a quicker sale. Since a mainly white paint scheme is easier to modify by the new owner.
White reflects sunlight
The next reason white is often chosen is thermodynamics. A white color helps to passively cool the aircraft. White surfaces tend to reflect a lot of sunlight. This reduces the build-up of heat and also the potential damage from solar radiation during the life of the plane. Heat and solar radiation can particularly damage the non-metal parts of the plane made of plastics or composite materials like fiberglass or carbon fiber.
This is why parts such as the nose cone of the plane where the aircraft radar is housed in the control surfaces which are made of composite materials are all usually painted white. It is vital that these parts of the plane are protected as much as possible.
The Concorde for example use specially designed highly reflective white paint. Which could withstand the extreme heat generated during supersonic flight. At its nose temperatures could reach as much as 127 degrees Celsius. To mitigate this a special white paint with a very high reflectivity was created.
White paints acts as insurance policy
The next reason is that white paint is something of an insurance policy. Using a mainly white paint scheme makes it easier to spot cracks dent and oil spills. The color white is also very easy to spot from a distance. It does reflect a lot of light after all. So in case of a tragic plane crash it would in theory at least be easier to find the wreckage during search and rescue.
White paint also doesn’t really fade like other colored paints. This means you don’t need to repaint the plane as often. Moreover according to some estimates a single layer of paint to an entire Boeing 737 adds around 180 kilograms to its total weight. For the larger 747 this could add as much as 500 kilograms. Adding layers of paint to the plane and increasing its overall weight results in more fuel consumption and more overheads.
Painted white aircraft keeps birds away
Finally white paint also helps keep the birds away. According to research, by enhancing the planes visibility, you can actually reduce the chance of birds striking the plane. Lighter color increases the contrast between the aircraft and the background. In theory helping birds to detect the aircraft in time to veer out of the way.
Next time you find yourself in an airport with a few hours to spare. You can audit the chosen color schemes of various commercial airliners. You may find yourself shaking your head at the foolishness of their choice of paint scheme.
Source: https://www.janathapulse.com/why-are-planes-usually-painted-white/
Tuesday, May 10, 2022
Meridians and Time Zones
Longitude is measured by imaginary lines that run around the Earth vertically (up and down) and meet at the North and South Poles. These lines are known as meridians. Each meridian measures one arcdegree of longitude. The distance around the Earth measures 360 degrees.
The prime meridian is the line of 0 longitude, the starting point for measuring distance both east and west around the Earth.
The prime meridian is arbitrary, meaning it could be chosen to be anywhere. Any line of longitude (a meridian) can serve as the 0 longitude line. However, there is an international agreement that the meridian that runs through Greenwich, England, is considered the official prime meridian.
Governments did not always agree that the Greenwich meridian was the prime meridian, making navigation over long distances very difficult. Different countries published maps and charts with longitude based on the meridian passing through their capital city. France would publish maps with 0 longitude running through Paris. Cartographers in China would publish maps with 0 longitude running through Beijing. Even different parts of the same country published materials based on local meridians.
Finally, at an international convention called by U.S. President Chester Arthur in 1884, representatives from 25 countries agreed to pick a single, standard meridian. They chose the meridian passing through the Royal Observatory in Greenwich, England. The Greenwich Meridian became the international standard for the prime meridian.
UTC
The prime meridian also sets Coordinated Universal Time (UTC). UTC never changes for daylight savings or anything else. Just as the prime meridian is the standard for longitude, UTC is the standard for time. All countries and regions measure their time zones according to UTC.
There are 24 time zones in the world. If an event happens at 11:00 a.m. in Houston, Texas, it would be reported at 12 p.m. in Orlando, Florida; 4:00 p.m. in Morocco; 9:00 p.m. in Kolkata, India; and 6:00 a.m. in Honolulu, Hawaii. The event happened at 4:00 p.m. UTC.
The prime meridian also helps establish the International Date Line. The Earth's longitude measures 360, so the halfway point from the prime meridian is the 180 longitude line. The meridian at 180 longitude is commonly known as the International Date Line. As you pass the International Date Line, you either add a day (going west) or subtract a day (going east.)
Hemispheres
The prime meridian and the International Date Line create a circle that divides the Earth into the eastern and western hemispheres. This is similar to the way the Equator serves as the 0 latitude line and divides the Earth into the northern and southern hemispheres.
The eastern hemisphere is east of the prime meridian and west of the International Date Line. Most of Earths landmasses, including all of Asia and Australia, and most of Africa, are part of the eastern hemisphere.
The western hemisphere is west of the prime meridian and east of the International Date Line. The Americas, the western part of the British Isles (including Ireland and Wales), and the northwestern part of Africa are landmasses in the western hemisphere.
Thursday, May 5, 2022
Wolves and the Hunt
THE WOLF is a PREDATOR
What the wolf lacks in size, power and weapons it makes up for with collaboration and intelligence. Smaller and less powerful than mountain lions, for example, wolves work together to take down prey much larger than an individual wolf; prey that may otherwise elude them. While individual wolves have been able to subdue large prey animals, their advantage is in collaborating with their pack.
Wolves are opportunists. They test their prey, sensing any weakness or vulnerability through visual cues and even through hearing and scent. Contrary to ambush predators that rely on the element of surprise and a short and intense burst of energy to secure their prey, wolves are endurance or coursing predators. They chase their prey, often over longer distances, sometimes even a few miles, in order to find the right animal or opportunity. On the hunt, wolves work together with certain individuals typically carrying out their specific role in the hunt, often based on age, gender and social standing.
While wolves will eat hares and other small prey, their preferred targets are ungulates, large hoofed animals such as deer and elk. Individual packs will specialize in hunting specific prey species. While most often that is elk, caribou, deer and moose, it can also be bison, muskoxen, small sheep or even salmon.
It is not uncommon for wolves to be injured or even killed during the hunt by being kicked by a hoof or gored by an antler. Most often the prey they select is in some way weaker and/or more vulnerable than the other animals in the herd. They may be injured, sick, old, very young or genetically inferior. But even healthier animals can at times find themselves in a vulnerable position. Over time this process allows the most capable prey animals to survive and pass on their genes and it helps to limit the spread of diseases within the herd.
THE HUNT
It is during a hunt where co-operation between wolves within a pack is most apparent. A wolf pack may trail a herd of elk, caribou or other large prey for days before making its move. During this time, they are already hunting, assessing the herd, looking for an animal that displays any sign of weakness, and this is just the beginning. Wolves must also factor in other conditions that will affect the hunt; weather and terrain can tip the scales in favor of predator or prey. For example, a wide-open plain favors the ungulates, who, if full-grown and healthy, can outrun the fastest wolf. On the other hand, crusty snow or ice favors the wolves whose wide round paws perform like snowshoes and carry them effortlessly over the surface. An experienced wolf is well aware that hoofed animals break through the crust and can become bogged down in deep snow.
Wolves have learned to use these conditions to their advantage. The late wolf biologist, Dr. Gordon Haber speaks of a particular pack in Alaska that he observed following a herd of caribou on a narrow packed trail through deep snow. The wolves know that their mere presence, following close behind, will eventually panic the caribou. When the rearmost caribou spooks, leaving the hard trail and attempting to run to the middle of the herd, it founders in the snowdrifts. When that happens it is all over. In warm weather, this same pack of wolves changes its tactics, herding the caribou into a dry riverbed where many of the ungulates stumble on the round stones.
A wolf pack therefore weighs many different factors when selecting its target and, as circumstances change during the hunt the target may change as well. Initially they may be pursuing a calf, but if a big healthy bull stumbles unexpectedly, they all know to go after the bigger meal. Conversely, if too many factors seem to favor the prey, they may choose to wait. Sometimes it is better to stay a bit hungry until the odds improve rather than expend precious energy on a fruitless chase.
Other observers of wolves have reported that often fewer than half of wolves on a hunt are actually involved with physically bringing down the prey. The youngest wolves frequently do nothing more than observe and learn from the sidelines. Each of the other pack members contributes according to its particular experience and ability. Speedy, lightly built females often take on herding roles, darting back and forth in front of prey, causing confusion and preventing escape. Slower but more powerful males are able to take down a large animal more aggressively and quickly.
Some of the wolf’s bad reputation stems from the apparent mob scene that ensues when the prey begins to falter. Wolves are not equipped to dispatch their victims quickly; prey usually die of shock, muscle damage or blood loss. If it can, one of the stronger wolves will seize the prey by the nose and hold on tight, helping to bring about a more expeditious end, but the animal can still take many minutes before it succumbs. Equipped only with feet for running and jaws for biting, wolves make the best of their limitations. A wolf pack’s ferocity and apparent brutality is really a defensive measure. It is not rare for a wolf to be seriously injured by flailing hooves and slashing antlers. A well-placed kick could break a wolf’s jaw, rendering it unable to feed itself. It is much safer to harass the prey and let it tire out before moving in close. Far from being a mob scene, a hunt is a masterfully coordinated group effort, well deserving of our admiration.
Although the alpha male is usually in the thick of the hunt, it would be an exaggeration to say that he is leading it. The alpha may select the animal to be pursued, or he may chose to break off the hunt if it is going poorly. But he is not barking out orders to his subordinates like a general on the battlefield. The wolves just seem to know what to do, and they do it as one.
The young wolves watch the behavior of the adults and see how the game is played. They witness how the adults change their strategy according to conditions and type of prey. They learn how the hunters handle each different situation: what to do when the prey dashes for open ground, or jumps into a river, or turns to defend itself.
When juvenile wolves finally join in the hunt, they imitate the more experienced wolves and perfect the precise skills of herding and tackling. By the time they are full grown adults, they have become part of a well-oiled machine. Even if they were able to communicate verbally with each other during the hunt, it would be unnecessary. They know exactly what to expect from the others and what is expected of them.
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