Dieppe Raid essays

Dieppe Raid essays Many people believe that the Dieppe Raid was a success. This was in fact true. There were many things learned that tragic day, that will be with us for a long time to come. The Dieppe Raid gave allies the experience and knowledge to be successful in other raids, and confrontations. After the raid, allies became aware that there were elements ever so crucial to their further success. Learning the physical properties of the battleground soon became a must, along with learning to better arm and defend, and that the element of communication must be exercised to a high degree. The Dieppe raid carried with it a high cost, but the lessons learned were invaluable and led directly to the success of the Normandy landings. The Dieppe Raid was to be considered a learning experience for the Canadians. It was to be a test for future invasions. 4936 Canadians ¹, who were restlessly awaiting an opportunity such as this, were sent to a beach on the French coast. Accompanying them, were 1000 Canadians, and 50 Americans. On August 19, 1942, these brave men fought, many knowing that they would never return. Tragedy struck that day, roughly 907 men died, 1154 were wounded, and 1894 became prisoners of war ². This horrible loss may never have occurred, had the allies demonstrated better organization. At Dieppe, men walked onto that beach having no idea what to expect. The commanding officers in charge of setting up the attack had neglected to consult a topographical viewpoint of the beach ³. This would have clearly shown that landing on beaches surrounded by 100-200 foot cliffs would leave troops vulnerable, and unable to escape the awaiting Germans. This showed the allies that it was crucial to be fully knowledgeable on all physical terrain that was to be travelled in the future. Many men were gunned down before they were even given a chance to retaliate. Before they could even make it to shore, they were being slaughtered. Allies had ...

The 3 Types of Joints in the Body

The 3 Types of Joints in the Body Bones come together at places in the body called joints, which enable us to move our bodies in different ways. Key Takeaways: Joints Joints are locations in the body where bones meet. They enable movement and are classified by either their structure or function.Structural classifications of joints include fibrous, cartilaginous, and synovial joints.Functional classifications of joints include immovable, slightly movable, and freely movable joints.Freely movable (synovial) joints are most abundant and include six types: pivot, hinge, condyloid, saddle, plane, and ball-and-socket joints. There are three types of joints in the body. Synovial joints are freely movable and allow for motion at the location where bones meet. They provide a wide range of motion and flexibility. Other joints provide more stability and less flexibility. Bones at cartilaginous joints connected by cartilage and are slightly movable. Bones at fibrous joints are immovable and connected by fibrous connective tissue. Joints can be classified by either their structure or function. Structural classifications are based on how the bones at joints are connected. Fibrous, synovial, and cartilaginous are structural classifications of joints. Classifications based on joint function consider how movable bones are at joint locations. These classifications include immovable (synarthrosis), slightly movable (amphiarthrosis), and freely movable (diarthrosis) joints. Immovable (Fibrous) Joints Fibrous joints hold skull bones together to protect the brain. Leonello Calvetti/Stocktrek Images/Getty Images Immovable or fibrous joints are those that do not allow movement (or allow for only very slight movement) at joint locations. Bones at these joints have no joint cavity and are held together structurally by thick fibrous connective tissue, usually collagen. These joints are important for stability and protection. There are three types of immovable joints: sutures, syndesmosis, and gomphosis. Sutures: These narrow fibrous joints connect bones of the skull (excluding the jaw bone). In adults, the bones are held tightly together to protect the brain and help shape the face. In newborns and infants, bones at these joints are separated by a larger area of connective tissue and are more flexible. Overtime, cranial bones fuse together providing more stability and protection for the brain.Syndesmosis: This type of fibrous joint connects two bones that are relatively far apart. The bones are linked by ligaments or a thick membrane (interosseous membrane). A syndesmosis can be found between the bones of the forearm (ulna and radius) and between the two long bones of the lower leg (tibia and fibula).Gomphosis: This type of fibrous joint holds a tooth in place in its socket in the upper and lower jaw. A gomphosis is an exception to the rule that joints connect bone to bone, as it connects teeth to bone. This specialized joint is also called a peg and socket joint and allows for limi ted to no movement. Slightly Movable (Cartilaginous) Joints Intervertebral discs are cartilaginous joints, composed of thick fibrocartilage, that support bones while allowing limited movement. MedicalRF.com/Getty Images Slightly movable joints permit some movement but provide less stability than immovable joints. These joints can be structurally classified as cartilaginous joints, as bones are connected by cartilage at the joints. Cartilage is a tough, elastic connective tissue that helps to reduce friction between bones. Two types of cartilage may be found at cartilaginous joints: hyaline cartilage and fibrocartilage. Hyaline cartilage is very flexible and elastic, while fibrocartilage is stronger and less flexible. Cartilaginous joints formed with hyaline cartilage can be found between certain bones of the rib cage. Intervertebral discs located between spinal vertebrae are examples of slightly movable joints composed of fibrocartilage. The fibrocartilage provides support for bones while allowing for limited movement. These are important functions as it relates to the spinal column as spinal vertebrae help to protect the spinal cord. The pubic symphysis (which connects the right and left hip bones) is another example of a cartilaginous joint that unites bones with fibrocartilage. The pubic symphysis helps to support and stabilize the pelvis. Freely Movable (Synovial) Joints Synovial joints are freely movable and provide the greatest degree of mobility. OpenStax College/Wikimedia Commons/CC BY 3.0 Freely movable joints are classified structurally as synovial joints. Unlike fibrous and cartilaginous joints, synovial joints have a joint cavity (fluids of synovial joints include joints in the wrist, elbow, knees, shoulders, and hip. Three main structural components are found in all synovial joints and include a synovial cavity, articular capsule, and articular cartilage. Synovial Cavity: This space between adjacent bones is filled with synovial fluid and is where bones can move freely in relation to each another. Synovial fluid helps to prevent friction between bones.Articular Capsule: Composed of fibrous connective tissue, this capsule surrounds the joint and connects to adjacent bones. The inner layer of the capsule is lined with a synovial membrane that produces the thick synovial fluid.Articular Cartilage: Within the articular capsule, the rounded ends of adjacent bones are covered with smooth articular (relating to joints) cartilage composed of hyaline cartilage. Articular cartilage absorbs shock and provides a smooth surface for fluent movements. Additionally, bones at synovial joints may be supported by structures outside of the joint such as ligaments, tendons, and bursae (fluid-filled sacs that reduce friction between supporting structures at joints). Types of Synovial Joints in the Body OpenStax College/Wikimedia Commons/CC BY 3.0 Synovial joints allow for a number of different types of body movements. There are six types of synovial joints found at different locations in the body. Pivot Joint: This joint permits rotational movement around a single axis. One bone is encircled by a ring formed by the other bone at the joint and a ligament. The bone that pivots may either rotate within the ring or the ring may rotate around the bone. The joint between the first and second cervical vertebrae near the base of the skull is an example of a pivot joint. It allows the head to turn from side to side.Hinge Joint: This joint permits bending and straightening movements along one plane. Similar to a door hinge, movement is limited to a single direction. Examples of hinge joints include the elbow, knee, ankle, and joints between the bones of the fingers and toes.Condyloid Joint: Several different types of movements are allowed by this type of joint, including bending and straightening, side-to-side, and circular movements. One of the bones has an oval-shaped, or convex, end (male surface) that fits into the depressed oval-shaped, or concave end (female surface) of another bo ne. This type of joint can be found between the radius bone of the forearm and bones of the wrist. Saddle Joint: These distinct joints are very flexible, allowing for bending and straightening, side-to-side, and circular movements. The bones at these joints form what looks like a rider on a saddle. One bone is turned inward at one end, while the other is turned outward. An example of a saddle joint is the thumb joint between the thumb and palm.Plane Joint: Bones at this type of joint slide past each other in a gliding motion. The bones at plane joints are of similar size and the surfaces where the bones meet at the joint are nearly flat. These joints can be found between bones of the wrist and foot, as well as between the collar bone and shoulder blade.Ball-and-Socket Joint: These joints allow the greatest degree of motion permitting bending and straitening, side-to-side, circular, and rotational movement. The end of one bone at this type of joint is rounded (ball) and fits into the cupped end (socket) of another bone. The hip and shoulder joints are examples of ball-and-socket jo ints. Each of the different types of synovial joints allows for specialized movements that permit different degrees of motion. They may allow movement in a single direction only or movement along multiple planes, depending on the type of joint. The range of motion of a joint is therefore limited by the type of joint and by its supporting ligaments and muscles. Sources Betts, J. Gordon. Anatomy and Physiology. Kelly A. Young, James A. Wise, et al., OpenStax at Rice University. Chen, Hao. Heads, Shoulders, Elbows, Knees, and Toes: Modular Gdf5 Enhancers Control Different Joints in the Vertebrate Skeleton. Terence D. Capellini, Michael Schoor, et al., PLOS Genetics, November 30, 2016.

Team Locomotive Charter Assignment Example | Topics and Well Written Essays - 1750 words

Team Locomotive Charter - Assignment Example All of us have different skills and interests. But we decided to use our skills and interests in a fruitful manner so that each and every member of our team may benefit from the skills of others. As a group, we have created the shared goals of inspiring each member to pursue excellence inside and outside of the classroom. We also hope to improve our ability to communicate effectively as a diverse unit. Since we are from different parts of the world our effective communication might be obstructed by the language barriers. But we know that more than 80% of the ideas are communicated through nonverbal means. So language barrier may not affect us much. In addition, we hope to broaden our cultural horizons while learning how to effectively work as a unit. Globalization has brought many changes in the business world and most of the major companies are operating internationally now in order to exploit the business potentials in other countries. Even the biggest companies like Microsoft, Apple etc are looking for every expansion opportunities in other countries. Such internationalization of business has raised the importance of a multicultural workforce in organizations at present. It is difficult for Microsoft or Apple to operate in a country like India or China with the help of the Americans alone. They need a blend of the diverse workforce including the Americans, Indians, and Chinese in order to sustain their business successfully in these countries. Diversity in our group will definitely help us to learn more about how to work in a multicultural team environment and these learning may help us in our future endeavors also. Without establishing expectations, our goals would be nearly impossible to accomplish. We set our expectations high. We expect each member to attend each meeting unless an emergency arises. We also expect each member to put forth 100% at all times.

Atomic Energy Exercises Assignment Example | Topics and Well Written Essays - 750 words

Atomic Energy Exercises - Assignment Example An approximation of the distance of separation for curve 2 appears to be bigger than that of curve 1 thus accounting for the smaller energy than that of curve 1. The maximum amount of force that is needed to push the particles together is greater in curve 1 than in curve 2. This is because the vector force that pulls particles towards each other is inversely proportional to the square of the separation distance and directly proportional to the products of the two charges. Case 2 There is immense proton repulsion between the protons within the nucleus because of the Coulomb’s law electrostatic interactions. In this regard, the force that is exerted by the center protons towards the outer protons is inversely proportion to the proton’s square of the separation distance. The separation distance squared comes about because the force field of an isolated proton charge is uniform towards all directions and becomes diluted with the separation distance just like the area of the centered sphere of the point charge which increases as its radius increases. Case 3 For the incoming protons, their potential energy is smaller compared to when they reach the bottom pit in the center. From Coulomb’s law (f=kq1q2/r2), potential energy is the product of force and distance which is given by PE= kq1q2/r. This means that as the protons move from outside they are far apart from each other hence remarkably little potential energy. When protons are in the center, the particles are close to each other leading to a small separation distance thus a greater potential energy compared to that of incoming protons. Case 4 Binding energy is the mechanically required energy to disassemble an atom into nucleus and free electrons (Jones International University, 2011). Helium has a lower binding energy compared to beryllium and iron. This is because helium has an atomic mass of 2, beryllium has an atomic mass of 4, whereas iron has an atomic mass of 26. In this case, iron has the greatest binding energy because of its atomic mass that is larger than that of beryllium and helium. This is so because, from the periodic table (of elements), the elements with greater atomic mass have increasing binding energy than those with a small atomic mass up to elements that are heavier than xenon which do not obey this trend. This is due to the increasing nucleon force in the nucleus as an extra nucleon gets attracted to other nucleons making the nucleus to be tightly bound. On the other hand, the amount of energy needed to pull the nuclei together for a tight bound is less for in an iron atom than the beryllium and helium atom. This is due to the fact that iron atom has a larger atomic mass than the helium and beryllium atoms. The larger the atomic mass, the more the energy levels of an atom and the less the energy needed to push the nucleus together for a tight bound. Case 5 Uranium 238 has 92 protons and 146 neutrons. Its binding energy can be given by: a - b /A1/3 - cZ2/A4/3- d (N-Z) 2 /A2 Â ± e/A7/4. Where a = 14.0, b = 13.0, c = 0.585, d= 19.3, and e = 33. A is the number of nucleons, Z is the number of protons in the nucleus, and N is the number of neutrons in the nucleus. B.E/A = 14-13/238^1/3- 0.585x92^2/238^4/3 – 19.3 (146-92) ^2/238^2Â ± 33/238^7/4 = 0.1614-3.357-0.9936 Â ±0.002288 =-4.1892

Our Excessive Dependence on Technology Essay -- Journalistic Essays

Our Excessive Dependence on Technology Today, almost every business owns computers. At least 900,000 businesses use the Internet. Some, such as Amazon.com, are run only on the Internet. If the internet were to shut down, a lot of people would be without jobs. We have gradually become more and more dependent on technology. As a result, we have become weaker. In terms of Darwin's "only the strongest survive" the people of twenty years ago were far superior to the people of today because of their non-dependence on computers. First, there is the obvious decline in physical fitness. For example, in Vermont, the percentage of students who participate in at least three hours of physical activity a week has dropped from 70% to 64% in only two years. Fewer than half of all students participate in a muscle toning activity, such as weightlifting. And although it takes 150-200 minutes a week to truly develop physical fitness , less than 25% of all students participate in physical fitness classes five days a week. Although you probably shouldn't believe those stories your parents tell you...

Green Roof

Many people don’t know what green roof is. So, what it is? A green roof is not a surface painted green, it is a living surface of plants growing in a soil layer on top of the roof. A thinner or thicker soil layer is spread over the roof membrane itself, sometimes with a protective root barrier, often with a drainage layer underneath. On the substrate, draught-tolerant species of plants are grown. Roof vegetation like this one doesn’t at all damage the waterproofing membrane of the roof. In fact it protects it from the uv-light which does damage the membrane over time.There are two types of green roofs: extensive and intensive. There are some differences of its. An extensive roof has very thin soil layers, draught tolerant plants and requires little or almost no maintenance. The limitation here is in the choice of plants. Extensive roof can be established on a very thin layer of soil. An intensive roof garden has much thicker soil layers, and can look like an ordinary ga rden, with trees and shrubs. Intensive roofs are more park-like with easy access and may include anything from kitchen herbs to shrubs and small trees.This of course needs as much maintenance as a garden does, and can only be constructed on a roof that can bear heavy loads. (http://en. wikipedia. org/wiki/Green_roof) It doesn’t matter what type roof is, but construction is a similar. Construction includes drainage materials, plant materials and establishment methods. For each green roof project, different site conditions and your aims and motives will govern the choice of materials and establishment methods. Therefore, if you are planning to build a green roof, consider the following two sections carefully.There are some roof sections which are important. First is a waterproofing. The membrane is made waterproof, and it will stay waterproof unless it gets physically damaged or aged. What ages a bitumen membrane is mainly uv-light and temperature extremes. Unless the roof memb rane is damaged while laying the green roof, the soil and vegetation cover protects the membrane from these types of injuries later. (http://www. greenroof. se/? pid=32&sub=19) Second section is root barrier. The asphalt waterproofing itself is not classified as root resistant and had to be reinforced with a root barrier.This barrier consists of rubberized asphalt enforced with polyester and treated eight a root-repelling agent. There are also synthetic waterproofing membranes (like PVC liners) available that are root resistant and do not require an additional root barrier. Different countries have different building practices and rules for green roofs – and many countries have no rules at all yet. In Germany, for example, a root barrier is always laid under a green roof. This is to ensure that no roots can damage the waterproofing.A root barrier is sometimes incorporated in the drainage layer. It can be chemical and poisonous to plants, or it can be a thin copper sheet, or r ubber sealed so as to avoid seams. If your motive for having a green roof is sustainability and ecological consciousness, it’s a good idea to ask your contractor about the method. In Sweden, the usual practice is that under extensive roof vegetation (2 – 5 cm soil), where only sedums and moss can survive, an extra root barrier is not considered necessary, since the sedums used have weak roots, and moss has no roots at all.When the soil layer is thicker, and therefore can hold more water, other plants grow there, and there is a risk of getting weeds with more penetrative roots. Second layer is insulation. Insulation boards can be made from extruded polystyrene which has high water resistance and compressive strength. The main difference from the old roof is that the insulation layer must be places above the waterproofing membrane, but on the new roofs insulation must be located below the waterproofing. Second, but not less important, is drainage.The main reason for usin g a drainage layer is that if a lot of water drains off along the surface of the soil, this will cause erosion. The second reason, is that for roofs which are almost flat, too much water would remain on the roof, forming puddles. Especially sedum vegetation is adapted to dry conditions, and tends to rot if submerged. Besides, too much water available can lead to unwanted plants establishing on the roof. Another function of the drainage materials that are often used is to store some amount of water.This effect becomes more and more important the drier the conditions on the roof are, due to climate, a steeper slope or other conditions on the roof. Drainage materials used in green roofs include natural materials, recycled materials and manufactured drainage mats. (â€Å"Green roof systems† Susan K. Weiler, Katrin Scolz-Barth) And finally, the top layer is growing medium with plants. The growing medium provides nutrients and structure for the roots to anchor in. the proprietary m ixes of the manufacturer consist of a lightweight aggregate, expanded shale, and some compost.The organic components make up about three to six percent of the shallow planting areas. The mix for deeper planting areas has slightly more organics. This mix is also heavier and allows a higher water-holding capacity in order to support the larger plants of these areas. In conclusion, one has to realize that there is no cookie cutter approach when it comes to the design of a green roof section. Though certain layers are always present – waterproofing, root barrier, insulation, protection layer, drainage layer, growing medium – their actual composition varies widely responding to a particular situation. â€Å"Green roof – a case study† Christian Werthmann) Green roofs have many advantages. One is a cooling effect. It is very useful effect for individual houses at summer time. A black bitumen roof easily reaches temperatures of 80 ° Celsius in the summer. When a soil layer and the shading plants protect the roof, the surface temperature usually doesn’t rise above the surrounding air temperature. A study conducted by Environment Canada found a 26% reduction in summer cooling needs and a 26% reduction in winter heat losses when a green roof is used.In addition to this, the plants and soil evaporate water, creating a cooling effect, and a moister air, more comfortable to breathe. Cooling effect is useful at summer, but at winter there is another green roof feature – insulation. The soil layer provides an additional insulation. In warmer climates a green roof especially the versions with thicker soil layer, can make a difference in the heating required in the building. Life expectancy of the root membrane is also important. The waterproofing of the roof, for example bitumen, has a normal life expectancy of 25 years.After that it needs replacing. The reasons are that the uv-light from the sun makes the surface brittle, and then t he expansion and shrinking caused by the fluctuations in temperature, together with the loss of elasticity, causes cracks to form in the membrane. The high temperatures in themselves, above 60 ° Celsius, age the membrane. The green roof protects the waterproofing from both the uv-light and the temperature extremes, increasing the life expectancy of the membrane to at least 60 years. (http://www. greenroof. se/? pid=28&sub=19)One of the most important effects of green roofs in the cities is their potential for retaining and delaying rainwater during storms. The gutters and sewers in the city have to be big enough to cope with the amounts of water that falls during extreme storm events. As more and more surfaces in the built up areas are made hard and impermeable, less water can percolate naturally into the soil. This means that the sewers and treatment plants get higher and higher loads. For the water treatment plant this can be a great problem, since they take care of sewage as we ll as rainwater.If the sewage gets very diluted by a heavy rain, the sensitive chemical and microbiological processes are disturbed. Getting the balance back costs time and money, and in the meantime, sewage is less completely cleaned. Also, the treatment plants cannot store unlimited amounts of water, so during extreme rains, they are forced to let completely untreated water to the natural waters. The more rain water that is taken care of locally, the less often we will have to face these polluting events. (http://progressivetimes. wordpress. om/2010/10/04/one-roof-two-roofs-green-roofs-blue-roofs/) There are some effects which are interesting. The heat island effect. This is the effect that makes cities reach a higher average temperature than the countryside around them. The large amount of stone, asphalt and concrete in the towns and cities that absorb the heat from the sun in the daytime, and release it at night. An additional cause is the lack of trees and other vegetation. The night time temperature rises, and in the summer people suffers from sleeplessness. The cost of air condition goes up.Green roofs can protect from noise and electromagnetic radiation. Thick layers and plants can reduce noise in the outdoor environment and green roofs can reduce the electromagnetic radiation that enters a building to a great extent. (http://www. greenroof. se/? pid=28&sub=19) The most important problem in big cities is pollution. Green roof vegetation, as well as other vegetation, use CO2 for their respiration, and therefore reduce the negative effects of pollution. Best are highly productive plants, which in a year can produce a lot of biomass.An extensive green roof does not produce very much, but intensive ones could. In this case, it might be a question of a small extra advantage, when large surfaces of the cities rooftops are used for vegetation. This is not a method that can be used as an only solution to the problems of pollution and global warming, but togeth er with all the other beneficial effects of green roofs, it is a small step in the right direction. (http://www. greenroof. se/? pid=28&sub=19) Green roofs also provide habitats for plants, insects, and animals that otherwise have limited natural space in cities.In modern city planning, â€Å"green corridors† are planned into the cities, where parks and waterways can connect the city with the surrounding countryside, and get humans in closer contact with nature. In the places where there isn’t enough ground space for green space, the green corridors, and the habitats for animals don’t have to be discontinued, if the flat roofs are used. (http://www. greenroof. se/? pid=28&sub=19) Thus green roof save materials, energy and money, produce less waste, can protect from negative cities impact and what is the most important – is environmental friendly. However, green roof has some disadvantages.Weight is problematical field. A thin extensive green roof of the t ype widely used weighs about 50 kg/m2 when saturated with water. Lighter versions are available, that uses rock wool as substrate instead of soil, which gives a weight of about 35 kg/m2. Compare that to tiles that weigh 33 – 37 kg /m2, depending on the type. If you live in a region where you can expect snow, then weight has to be reckoned as well. So some buildings, especially old buildings, cannot be retrofitted with certain kinds of green roof because of the weight load of the substrate and vegetation exceeds permitted static loading.Depending on what kind of green roof it is, the maintenance costs could be higher. Cost is the main reason why people didn’t want green roofs. Properly designed and -installed systems include root barriers. It is true that installing adequate waterproofing systems and root barriers automatically can increase the initial cost of the roof. A properly designed and installed green-roof system can cost 15 to 20 dollars per square foot as a to tal cost, not including the roof's waterproof layers.In Europe, a well-designed and professionally installed fully integrated green roof can cost anywhere between 100 to 200 euros per square meter, depending on the kind of roof, the building structure, and which plants are used. Despite of that, I think that green roofs have more advantages than disadvantages. (http://en. wikipedia. org/wiki/Green_roof) It is clear that living green roofs and landscapes over structure are not a panacea for ameliorating the negative environmental impacts resulting from increased development or the loss of open space.They cannot and will not replace our forests and prairies, will nor remediate the degradation of all stream corridors, and will not stop global warming by themselves. However, green roofs and landscapes over structure can act buffers to mitigate the impacts of unbridled and unplanned urban growth and development. Reducing building roofs generates less storm water runoff, reduces the heat gain that affects our indoor and outdoor environments, and mitigates the continued degradation of air and water quality. Green roofs provide additional usable, confortable open space. Green Roof Many people don’t know what green roof is. So, what it is? A green roof is not a surface painted green, it is a living surface of plants growing in a soil layer on top of the roof. A thinner or thicker soil layer is spread over the roof membrane itself, sometimes with a protective root barrier, often with a drainage layer underneath. On the substrate, draught-tolerant species of plants are grown. Roof vegetation like this one doesn’t at all damage the waterproofing membrane of the roof. In fact it protects it from the uv-light which does damage the membrane over time.There are two types of green roofs: extensive and intensive. There are some differences of its. An extensive roof has very thin soil layers, draught tolerant plants and requires little or almost no maintenance. The limitation here is in the choice of plants. Extensive roof can be established on a very thin layer of soil. An intensive roof garden has much thicker soil layers, and can look like an ordinary ga rden, with trees and shrubs. Intensive roofs are more park-like with easy access and may include anything from kitchen herbs to shrubs and small trees.This of course needs as much maintenance as a garden does, and can only be constructed on a roof that can bear heavy loads. (http://en. wikipedia. org/wiki/Green_roof) It doesn’t matter what type roof is, but construction is a similar. Construction includes drainage materials, plant materials and establishment methods. For each green roof project, different site conditions and your aims and motives will govern the choice of materials and establishment methods. Therefore, if you are planning to build a green roof, consider the following two sections carefully.There are some roof sections which are important. First is a waterproofing. The membrane is made waterproof, and it will stay waterproof unless it gets physically damaged or aged. What ages a bitumen membrane is mainly uv-light and temperature extremes. Unless the roof memb rane is damaged while laying the green roof, the soil and vegetation cover protects the membrane from these types of injuries later. (http://www. greenroof. se/? pid=32&sub=19) Second section is root barrier. The asphalt waterproofing itself is not classified as root resistant and had to be reinforced with a root barrier.This barrier consists of rubberized asphalt enforced with polyester and treated eight a root-repelling agent. There are also synthetic waterproofing membranes (like PVC liners) available that are root resistant and do not require an additional root barrier. Different countries have different building practices and rules for green roofs – and many countries have no rules at all yet. In Germany, for example, a root barrier is always laid under a green roof. This is to ensure that no roots can damage the waterproofing.A root barrier is sometimes incorporated in the drainage layer. It can be chemical and poisonous to plants, or it can be a thin copper sheet, or r ubber sealed so as to avoid seams. If your motive for having a green roof is sustainability and ecological consciousness, it’s a good idea to ask your contractor about the method. In Sweden, the usual practice is that under extensive roof vegetation (2 – 5 cm soil), where only sedums and moss can survive, an extra root barrier is not considered necessary, since the sedums used have weak roots, and moss has no roots at all.When the soil layer is thicker, and therefore can hold more water, other plants grow there, and there is a risk of getting weeds with more penetrative roots. Second layer is insulation. Insulation boards can be made from extruded polystyrene which has high water resistance and compressive strength. The main difference from the old roof is that the insulation layer must be places above the waterproofing membrane, but on the new roofs insulation must be located below the waterproofing. Second, but not less important, is drainage.The main reason for usin g a drainage layer is that if a lot of water drains off along the surface of the soil, this will cause erosion. The second reason, is that for roofs which are almost flat, too much water would remain on the roof, forming puddles. Especially sedum vegetation is adapted to dry conditions, and tends to rot if submerged. Besides, too much water available can lead to unwanted plants establishing on the roof. Another function of the drainage materials that are often used is to store some amount of water.This effect becomes more and more important the drier the conditions on the roof are, due to climate, a steeper slope or other conditions on the roof. Drainage materials used in green roofs include natural materials, recycled materials and manufactured drainage mats. (â€Å"Green roof systems† Susan K. Weiler, Katrin Scolz-Barth) And finally, the top layer is growing medium with plants. The growing medium provides nutrients and structure for the roots to anchor in. the proprietary m ixes of the manufacturer consist of a lightweight aggregate, expanded shale, and some compost.The organic components make up about three to six percent of the shallow planting areas. The mix for deeper planting areas has slightly more organics. This mix is also heavier and allows a higher water-holding capacity in order to support the larger plants of these areas. In conclusion, one has to realize that there is no cookie cutter approach when it comes to the design of a green roof section. Though certain layers are always present – waterproofing, root barrier, insulation, protection layer, drainage layer, growing medium – their actual composition varies widely responding to a particular situation. â€Å"Green roof – a case study† Christian Werthmann) Green roofs have many advantages. One is a cooling effect. It is very useful effect for individual houses at summer time. A black bitumen roof easily reaches temperatures of 80 ° Celsius in the summer. When a soil layer and the shading plants protect the roof, the surface temperature usually doesn’t rise above the surrounding air temperature. A study conducted by Environment Canada found a 26% reduction in summer cooling needs and a 26% reduction in winter heat losses when a green roof is used.In addition to this, the plants and soil evaporate water, creating a cooling effect, and a moister air, more comfortable to breathe. Cooling effect is useful at summer, but at winter there is another green roof feature – insulation. The soil layer provides an additional insulation. In warmer climates a green roof especially the versions with thicker soil layer, can make a difference in the heating required in the building. Life expectancy of the root membrane is also important. The waterproofing of the roof, for example bitumen, has a normal life expectancy of 25 years.After that it needs replacing. The reasons are that the uv-light from the sun makes the surface brittle, and then t he expansion and shrinking caused by the fluctuations in temperature, together with the loss of elasticity, causes cracks to form in the membrane. The high temperatures in themselves, above 60 ° Celsius, age the membrane. The green roof protects the waterproofing from both the uv-light and the temperature extremes, increasing the life expectancy of the membrane to at least 60 years. (http://www. greenroof. se/? pid=28&sub=19)One of the most important effects of green roofs in the cities is their potential for retaining and delaying rainwater during storms. The gutters and sewers in the city have to be big enough to cope with the amounts of water that falls during extreme storm events. As more and more surfaces in the built up areas are made hard and impermeable, less water can percolate naturally into the soil. This means that the sewers and treatment plants get higher and higher loads. For the water treatment plant this can be a great problem, since they take care of sewage as we ll as rainwater.If the sewage gets very diluted by a heavy rain, the sensitive chemical and microbiological processes are disturbed. Getting the balance back costs time and money, and in the meantime, sewage is less completely cleaned. Also, the treatment plants cannot store unlimited amounts of water, so during extreme rains, they are forced to let completely untreated water to the natural waters. The more rain water that is taken care of locally, the less often we will have to face these polluting events. (http://progressivetimes. wordpress. om/2010/10/04/one-roof-two-roofs-green-roofs-blue-roofs/) There are some effects which are interesting. The heat island effect. This is the effect that makes cities reach a higher average temperature than the countryside around them. The large amount of stone, asphalt and concrete in the towns and cities that absorb the heat from the sun in the daytime, and release it at night. An additional cause is the lack of trees and other vegetation. The night time temperature rises, and in the summer people suffers from sleeplessness. The cost of air condition goes up.Green roofs can protect from noise and electromagnetic radiation. Thick layers and plants can reduce noise in the outdoor environment and green roofs can reduce the electromagnetic radiation that enters a building to a great extent. (http://www. greenroof. se/? pid=28&sub=19) The most important problem in big cities is pollution. Green roof vegetation, as well as other vegetation, use CO2 for their respiration, and therefore reduce the negative effects of pollution. Best are highly productive plants, which in a year can produce a lot of biomass.An extensive green roof does not produce very much, but intensive ones could. In this case, it might be a question of a small extra advantage, when large surfaces of the cities rooftops are used for vegetation. This is not a method that can be used as an only solution to the problems of pollution and global warming, but togeth er with all the other beneficial effects of green roofs, it is a small step in the right direction. (http://www. greenroof. se/? pid=28&sub=19) Green roofs also provide habitats for plants, insects, and animals that otherwise have limited natural space in cities.In modern city planning, â€Å"green corridors† are planned into the cities, where parks and waterways can connect the city with the surrounding countryside, and get humans in closer contact with nature. In the places where there isn’t enough ground space for green space, the green corridors, and the habitats for animals don’t have to be discontinued, if the flat roofs are used. (http://www. greenroof. se/? pid=28&sub=19) Thus green roof save materials, energy and money, produce less waste, can protect from negative cities impact and what is the most important – is environmental friendly. However, green roof has some disadvantages.Weight is problematical field. A thin extensive green roof of the t ype widely used weighs about 50 kg/m2 when saturated with water. Lighter versions are available, that uses rock wool as substrate instead of soil, which gives a weight of about 35 kg/m2. Compare that to tiles that weigh 33 – 37 kg /m2, depending on the type. If you live in a region where you can expect snow, then weight has to be reckoned as well. So some buildings, especially old buildings, cannot be retrofitted with certain kinds of green roof because of the weight load of the substrate and vegetation exceeds permitted static loading.Depending on what kind of green roof it is, the maintenance costs could be higher. Cost is the main reason why people didn’t want green roofs. Properly designed and -installed systems include root barriers. It is true that installing adequate waterproofing systems and root barriers automatically can increase the initial cost of the roof. A properly designed and installed green-roof system can cost 15 to 20 dollars per square foot as a to tal cost, not including the roof's waterproof layers.In Europe, a well-designed and professionally installed fully integrated green roof can cost anywhere between 100 to 200 euros per square meter, depending on the kind of roof, the building structure, and which plants are used. Despite of that, I think that green roofs have more advantages than disadvantages. (http://en. wikipedia. org/wiki/Green_roof) It is clear that living green roofs and landscapes over structure are not a panacea for ameliorating the negative environmental impacts resulting from increased development or the loss of open space.They cannot and will not replace our forests and prairies, will nor remediate the degradation of all stream corridors, and will not stop global warming by themselves. However, green roofs and landscapes over structure can act buffers to mitigate the impacts of unbridled and unplanned urban growth and development. Reducing building roofs generates less storm water runoff, reduces the heat gain that affects our indoor and outdoor environments, and mitigates the continued degradation of air and water quality. Green roofs provide additional usable, confortable open space.

Percival Lowell Astronomer Who Looked for Life on Mars

Percival Lowell (March 13, 1855–November 12, 1916) was a businessman and astronomer born into Bostons wealthy Lowell family. He devoted much of his life to the search for life on Mars, which he conducted from the observatory he built in Flagstaff, Arizona. His theory of the presence of canals on Mars was ultimately disproved, but later in life, he laid the groundwork for the discovery of Pluto. Lowell is also remembered for founding the Lowell Observatory, which continues to contribute to astronomical research and learning to this day. Fast Facts: Percival Lowell Full Name: Percival Lawrence LowellKnown For: Businessman and astronomer who founded the Lowell Observatory, enabled the discovery of Pluto, and fueled the (later disproved) theory that canals existed on Mars.Born: March 13, 1855 in Boston, Massachusetts, USAParents Names: Augustus Lowell and Katherine Bigelow LowellEducation: Harvard University Died: November 12, 1916 in Flagstaff, Arizona, USAPublications: ChosÃ… n, Mars, Mars as the Abode of Life, Memoirs of a Trans-Neptunian PlanetSpouses Name: Constance Savage Keith Lowell Early Life Percival Lowell was born in Boston, Massachusetts on March 13, 1855. He was a member of the wealthy Lowell clan, famous in the Boston area for its long involvement in textiles and philanthropy. He was related to the poet Amy Lowell and the lawyer and legal expert Abbott Lawrence Lowell, and the town of Lowell, Massachusetts was named for the family. Percivals early education included private schools in England, France, and the United States. He attended Harvard University, graduating in 1876 with a degree in mathematics. After graduation, he ran one of the familys textile mills, then traveled throughout Asia before taking a position as a foreign secretary at the Korean diplomatic mission. He was fascinated with Asian philosophies and religions, and ultimately wrote his first book about Korea (ChosÃ… n: the Land of the Morning Calm, a Sketch of Korea). He moved back to the United States after 12 years living in Asia. The Search for Life on Mars Lowell was fascinated by astronomy from an early age. He read books on the topic, and was particularly inspired by astronomer Giovanni Schiaparellis description of canali on Mars. Canali is the Italian word for channels, but it was mistranslated to mean canals—defined as man-made waterways and consequently implying the presence of life on mars. Thanks to this mistranslation, Lowell began studying Mars to find proof of intelligent life. The quest kept his attention for the rest of his life. In 1894, Lowell traveled to Flagstaff, Arizona in search of clear, dark skies and a dry climate. There, he built the Lowell Observatory, where he spent the next 15 years studying Mars through a 24-inch Alvan Clark Sons telescope. He felt that the markings he saw on the planet werent natural, and set out to catalog all the surface features he could see through the telescope. Lowell made extensive drawings of the Mars, documenting the canals he believed he was seeing. He theorized that a Martian civilization, faced with climate change, had built the canals to transport water from the planets ice caps to irrigate crops. He published several books, including Mars (1885), Mars and its Canals (1906), and Mars as the Abode of Life (1908). In his books, Lowell built a careful rationale for the existence of intelligent life on the red planet.   A drawing by Percival Lowell (1896) depicting canals and dark areas on Mars. Photo by Ann Ronan Pictures/Print Collector/Getty Images Lowell was convinced that life existed on Mars, and the idea of Martians was widely accepted by the public at the time. However, these views were not shared by the scientific establishment. Larger observatories were unable to find Lowells finely-drawn network of canals, even with a markedly more powerful telescope than the one Lowell used. Lowells canal theory was finally disproved in the 1960s. Over the years, various hypotheses about what Lowell was actually seeing have been proposed. Its likely that the wavering of our atmosphere—plus some wishful thinking—caused Percival Lowell to see canals on Mars. Nonetheless, he persisted in his observations, and in the process, also charted a number of natural surface features on the planet.   Planet X and the Discovery of Pluto Mars was not the only object that drew Lowells attention. He also observed Venus, believing that he could spot some surface markings. (It was later demonstrated that no one can see the surface of Venus from Earth due to the heavy cloud cover that blankets the planet.) He also inspired the search for a world that he believed was orbiting beyond the orbit of Neptune. He called this world Planet X. Lowell Observatory continued to grow, fueled by Lowells wealth. The observatory installed a 42-inch telescope equipped with a camera so that astronomers could photograph the sky in search of Planet X. Lowell hired Clyde Tombaugh to participate in the search. In 1915, Lowell published a book about the search: Memoir of a Trans-Neptunian Planet. In 1930, after Lowells death, Tombaugh succeeded when he discovered Pluto. That discovery took the world by storm as the most distant planet ever discovered. Later Life and Legacy Percival Lowell lived and worked at the observatory for the remainder of his life. He continued his work observing Mars and using his observatory (along with a crew of dedicated observers and astronomers) until his death in 1916. Lowells legacy continues as Lowell Observatory enters its second century of service to astronomy. Over the years, the facilities have been used for moon mapping for the NASA Apollo program, studies of rings around Uranus, observations of the atmosphere of Pluto, and hosts of other research programs. Sources Britannica, T. E. (2018, March 08). Percival Lowell. https://www.britannica.com/biography/Percival-LowellHistory. https://lowell.edu/history/.Lowell, A. Lawrence. Biography of Percival Lowell. https://www.gutenberg.org/files/51900/51900-h/51900-h.htm.