Disadvantages of Plastics are
1. Flammable – This is definitely an advantage in that they can be melted down, however smoldering plastics can release toxic fumes into the environment.
2. Cost of Recycling – While recycling is a plus, recycling is a very costly endeavor.
3. Volume – In the United States 20% of our landfill is made up of plastics. As more products are being made of plastics, where will this lead us in the future?
4. Durability – This is an advantage as well as a disadvantage. Plastics are extremely durable, which means that they last a long time. Those plastics in the landfill will be there for years.
Plastics make our lives easier, however is their cost on the environment worth it? We can only hope that soon someone will invent a way to safely and cheaply melt and reuse plastics.
A plastic material is any of a wide range of synthetic or semi-synthetic organic amorphous solids[citation needed] used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce costs. Monomers of plastic are either natural or synthetic organic compounds.
The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their malleability, or plasticity during manufacture, that allows them to be cast, pressed, or extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and much more.
The common word plastic should not be confused with the technical adjective plastic, which is applied to any material which undergoes a permanent change of shape (plastic deformation) when strained beyond a certain point. Aluminum, for instance, is plastic in this sense, but not a plastic in the common sense; in contrast, in their finished forms, some plastics will break before deforming and therefore are not plastic in the technical sense.
There are two types of plastics: thermoplastics and thermosetting polymers. Thermoplastics will soften and melt if enough heat is applied; examples are polyethylene, polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE)[3]. Thermosets can melt and take shape once; after they have solidified, they stay solid.
Overview
Plastics can be classified by chemical structure, namely the molecular units that make up the polymer's backbone and side chains. Some important groups in these classifications are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics can also be classified by the chemical process used in their synthesis, such as condensation, polyaddition, and cross-linking.[4]
Other classifications are based on qualities that are relevant for manufacturing or product design. Examples of such classes are the thermoplastic and thermoset, elastomer, structural, biodegradable, and electrically conductive. Plastics can also be classified by various physical properties, such as density, tensile strength, glass transition temperature, and resistance to various chemical products.
Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their former uses.
The use of plastics is constrained chiefly by their organic chemistry, which seriously limits their hardness, density, and their ability to resist heat, organic solvents, oxidation, and ionizing radiation. In particular, most plastics will melt or decompose when heated to a few hundred degrees celsius.[5] While plastics can be made electrically conductive to some extent, they are still no match for metals like copper or aluminum.[citation needed] Plastics are still too expensive to replace wood, concrete and ceramic in bulky items like ordinary buildings, bridges, dams, pavement, and railroad ties.
Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are assumed to have infinite molecular weight. These chains are made up of many repeating molecular units, known as repeat units, derived from monomers; each polymer chain will have several thousand repeating units. The vast majority of plastics are composed of polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the backbone. (Some of commercial interests are silicon based.) The backbone is that part of the chain on the main "path" linking a large number of repeat units together. To customize the properties of a plastic, different molecular groups "hang" from the backbone (usually they are "hung" as part of the monomers before linking monomers together to form the polymer chain). This fine tuning of the properties of the polymer by repeating unit's molecular structure has allowed plastics to become such an indispensable part of twenty first-century world.
Some plastics are partially crystalline and partially amorphous in molecular structure, giving them both a melting point (the temperature at which the attractive intermolecular forces are overcome) and one or more glass transitions (temperatures above which the extent of localized molecular flexibility is substantially increased). The so-called semi-crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride), polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all thermosets.
Almost every market that you go today, you will see people carrying their shopping items in plastic bags. Right from food items to clothes to shoes, there is hardly any item that we do not use a plastic bag to carry. However, before stuffing your home with different styles, colors and shapes of plastic bags, have you every considered the dangers that are inherent in using them? No? Then, reading through this article is a must for you. Go through the following lines and explore the disadvantages of plastic bags. After reading them, we are sure that you will prefer sticking to paper bags and the like.
Dangers Of Using Plastic Bags
Environmental Damage
Plastic bags have been known to cause a lot of environmental damage. A single plastic bag can take up to 1000 years, to decay completely. This makes the bags stay in environments longer, in turn leading to great build-up on the natural landscape (much more than degradable materials like paper). In other words, the more plastic bags you use, the greater the chances of environmental damage.
Threat To Animal Life
As per Marrickville Council of Australia, as many as 100,000 whales, turtles and birds die have been reported to die every year, mainly because of plastic in their environment. Plastic bags not only have adverse effects on our natural habitats, but have also been found to be responsible for the death of many animals, mainly on account of the suffocation encountered on eating them.
Suffocation
Not only animals, infants and young children have also been reported to have lost their life, on account of plastic bags. Since plastic bags are thin and airtight as well, children often end up blocking their mouths and nostrils with them. In case they are not being monitored by an adult, this leads to suffocation and, in some cases, even death.
Pollution
Plastic bags are extremely durable. In case you are thinking of this as an advantage, just bring to mind an image of the huge landfill that you visited on the city outskirts, the other day. In most probability, majority of the rubbish present there will comprise of plastic bags only. In other words, plastic bags have led to a great increase in the pollution levels.
Fumes
Since plastic bags are not bio-degradable, the only way to get rid of them is to burn them up. Though lighting a match to them is easy, it has more than its fair share of disadvantages. The biggest of them is that smoldering plastics can release toxic fumes into the environment, in turn taking the air pollution to much higher levels.
Non-renewable
One of the main disadvantages of plastic bags is that they are not renewable. The reason behind this is that they are made of petrochemicals, a non-renewable source of energy. They can be recycled, but not as easily as paper bags. Plastic bags can last for as much as hundred of years. In other words, long after you are no more, the plastic bag used by you will be in existence.
Plastics are manufactured from petroleum. This brings a host of issues (destruction of habitat, extraction of crude oil, security issues from the volatile countries where oil is produced, processing of petroleum, chemical manipulation into various types of plastics). The manufacture involves many chemicals, many of which have not been sufficiently tested for their toxicological impact on humans or animals.
The final plastic product is often a chemical entity that in and of itself has had insufficient toxicological and ecotoxicological testing. An example would be PVC, forms of which are banned in Europe but exist widely in children's toys in America. Recent controversies over plastic bottles (many toxicologists recommending not re-using plastic water bottles and not storing food in tupperware) have highlighted the potential risks. Exacerbating the problem is that science is only now advancing to where it can detect plastic components in human blood and then trace concentrations and link them to human ailments and diseases.
The plastics industry itself often spins plastic and related plastic chemicals into a variety of products, some of which are hazardous and controversial (Teflon, PVC, Polyethylene, polystyrene, various silicones in body and hair care). Plastic-producing companies are often chemical companies or subsidiaries of chemical companies, both with poor track records when it comes to their adherence to regulatory compliance and their willingness to perform toxicological analysis on the products they make.
Plastics often leech component chemicals, including hazardous chemicals, through common temperature changes. It is for this reason that toxicologists do not recommend storing very cold foods in plastics or heating foods (microwaving especially) in plastics.
Plastics are durable materials. Thus, they are hard to eliminate once used and create tremendous waste. While some common plastics can be recycled (#1 and #2 plastics used in common soda and milk bottles), the vast majority cannot. They take up a lot of space in landfills and create air pollution when incinerated.
The Disadvantages of Plastic Skylights
Although plastic skylights are safer and sturdier than glass skylights, they do pose several long term disadvantages. Firstly, because they are made in single sheets, they can only be curved or bent in one area, which limits design options. Secondly, all plastics deteriorate in strength and light transmission as time passes, due to ultraviolet rays, heat and oxidation (and none can be entirely prevented). And finally, the life and service of plastic materials is highly unpredictable. Therefore choosing the plastics you will use for a plastic skylight requires much research and first hand knowledge. This is where Roof 101 can help – our contractors have worked with all kinds of plastics in plastic skylights, and their first hand experience could greatly assist you in reaching a decision.
Monday, June 28, 2010
Disadvantages of Plastics
Disadvantages of Plastics are
1. Flammable – This is definitely an advantage in that they can be melted down, however smoldering plastics can release toxic fumes into the environment.
2. Cost of Recycling – While recycling is a plus, recycling is a very costly endeavor.
3. Volume – In the United States 20% of our landfill is made up of plastics. As more products are being made of plastics, where will this lead us in the future?
4. Durability – This is an advantage as well as a disadvantage. Plastics are extremely durable, which means that they last a long time. Those plastics in the landfill will be there for years.
Plastics make our lives easier, however is their cost on the environment worth it? We can only hope that soon someone will invent a way to safely and cheaply melt and reuse plastics.
A plastic material is any of a wide range of synthetic or semi-synthetic organic amorphous solids[citation needed] used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce costs. Monomers of plastic are either natural or synthetic organic compounds.
The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their malleability, or plasticity during manufacture, that allows them to be cast, pressed, or extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and much more.
The common word plastic should not be confused with the technical adjective plastic, which is applied to any material which undergoes a permanent change of shape (plastic deformation) when strained beyond a certain point. Aluminum, for instance, is plastic in this sense, but not a plastic in the common sense; in contrast, in their finished forms, some plastics will break before deforming and therefore are not plastic in the technical sense.
There are two types of plastics: thermoplastics and thermosetting polymers. Thermoplastics will soften and melt if enough heat is applied; examples are polyethylene, polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE)[3]. Thermosets can melt and take shape once; after they have solidified, they stay solid.
Overview
Plastics can be classified by chemical structure, namely the molecular units that make up the polymer's backbone and side chains. Some important groups in these classifications are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics can also be classified by the chemical process used in their synthesis, such as condensation, polyaddition, and cross-linking.[4]
Other classifications are based on qualities that are relevant for manufacturing or product design. Examples of such classes are the thermoplastic and thermoset, elastomer, structural, biodegradable, and electrically conductive. Plastics can also be classified by various physical properties, such as density, tensile strength, glass transition temperature, and resistance to various chemical products.
Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their former uses.
The use of plastics is constrained chiefly by their organic chemistry, which seriously limits their hardness, density, and their ability to resist heat, organic solvents, oxidation, and ionizing radiation. In particular, most plastics will melt or decompose when heated to a few hundred degrees celsius.[5] While plastics can be made electrically conductive to some extent, they are still no match for metals like copper or aluminum.[citation needed] Plastics are still too expensive to replace wood, concrete and ceramic in bulky items like ordinary buildings, bridges, dams, pavement, and railroad ties.
Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are assumed to have infinite molecular weight. These chains are made up of many repeating molecular units, known as repeat units, derived from monomers; each polymer chain will have several thousand repeating units. The vast majority of plastics are composed of polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the backbone. (Some of commercial interests are silicon based.) The backbone is that part of the chain on the main "path" linking a large number of repeat units together. To customize the properties of a plastic, different molecular groups "hang" from the backbone (usually they are "hung" as part of the monomers before linking monomers together to form the polymer chain). This fine tuning of the properties of the polymer by repeating unit's molecular structure has allowed plastics to become such an indispensable part of twenty first-century world.
Some plastics are partially crystalline and partially amorphous in molecular structure, giving them both a melting point (the temperature at which the attractive intermolecular forces are overcome) and one or more glass transitions (temperatures above which the extent of localized molecular flexibility is substantially increased). The so-called semi-crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride), polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all thermosets.
Almost every market that you go today, you will see people carrying their shopping items in plastic bags. Right from food items to clothes to shoes, there is hardly any item that we do not use a plastic bag to carry. However, before stuffing your home with different styles, colors and shapes of plastic bags, have you every considered the dangers that are inherent in using them? No? Then, reading through this article is a must for you. Go through the following lines and explore the disadvantages of plastic bags. After reading them, we are sure that you will prefer sticking to paper bags and the like.
Dangers Of Using Plastic Bags
Environmental Damage
Plastic bags have been known to cause a lot of environmental damage. A single plastic bag can take up to 1000 years, to decay completely. This makes the bags stay in environments longer, in turn leading to great build-up on the natural landscape (much more than degradable materials like paper). In other words, the more plastic bags you use, the greater the chances of environmental damage.
Threat To Animal Life
As per Marrickville Council of Australia, as many as 100,000 whales, turtles and birds die have been reported to die every year, mainly because of plastic in their environment. Plastic bags not only have adverse effects on our natural habitats, but have also been found to be responsible for the death of many animals, mainly on account of the suffocation encountered on eating them.
Suffocation
Not only animals, infants and young children have also been reported to have lost their life, on account of plastic bags. Since plastic bags are thin and airtight as well, children often end up blocking their mouths and nostrils with them. In case they are not being monitored by an adult, this leads to suffocation and, in some cases, even death.
Pollution
Plastic bags are extremely durable. In case you are thinking of this as an advantage, just bring to mind an image of the huge landfill that you visited on the city outskirts, the other day. In most probability, majority of the rubbish present there will comprise of plastic bags only. In other words, plastic bags have led to a great increase in the pollution levels.
Fumes
Since plastic bags are not bio-degradable, the only way to get rid of them is to burn them up. Though lighting a match to them is easy, it has more than its fair share of disadvantages. The biggest of them is that smoldering plastics can release toxic fumes into the environment, in turn taking the air pollution to much higher levels.
Non-renewable
One of the main disadvantages of plastic bags is that they are not renewable. The reason behind this is that they are made of petrochemicals, a non-renewable source of energy. They can be recycled, but not as easily as paper bags. Plastic bags can last for as much as hundred of years. In other words, long after you are no more, the plastic bag used by you will be in existence.
Plastics are manufactured from petroleum. This brings a host of issues (destruction of habitat, extraction of crude oil, security issues from the volatile countries where oil is produced, processing of petroleum, chemical manipulation into various types of plastics). The manufacture involves many chemicals, many of which have not been sufficiently tested for their toxicological impact on humans or animals.
The final plastic product is often a chemical entity that in and of itself has had insufficient toxicological and ecotoxicological testing. An example would be PVC, forms of which are banned in Europe but exist widely in children's toys in America. Recent controversies over plastic bottles (many toxicologists recommending not re-using plastic water bottles and not storing food in tupperware) have highlighted the potential risks. Exacerbating the problem is that science is only now advancing to where it can detect plastic components in human blood and then trace concentrations and link them to human ailments and diseases.
The plastics industry itself often spins plastic and related plastic chemicals into a variety of products, some of which are hazardous and controversial (Teflon, PVC, Polyethylene, polystyrene, various silicones in body and hair care). Plastic-producing companies are often chemical companies or subsidiaries of chemical companies, both with poor track records when it comes to their adherence to regulatory compliance and their willingness to perform toxicological analysis on the products they make.
Plastics often leech component chemicals, including hazardous chemicals, through common temperature changes. It is for this reason that toxicologists do not recommend storing very cold foods in plastics or heating foods (microwaving especially) in plastics.
Plastics are durable materials. Thus, they are hard to eliminate once used and create tremendous waste. While some common plastics can be recycled (#1 and #2 plastics used in common soda and milk bottles), the vast majority cannot. They take up a lot of space in landfills and create air pollution when incinerated.
The Disadvantages of Plastic Skylights
Although plastic skylights are safer and sturdier than glass skylights, they do pose several long term disadvantages. Firstly, because they are made in single sheets, they can only be curved or bent in one area, which limits design options. Secondly, all plastics deteriorate in strength and light transmission as time passes, due to ultraviolet rays, heat and oxidation (and none can be entirely prevented). And finally, the life and service of plastic materials is highly unpredictable. Therefore choosing the plastics you will use for a plastic skylight requires much research and first hand knowledge. This is where Roof 101 can help – our contractors have worked with all kinds of plastics in plastic skylights, and their first hand experience could greatly assist you in reaching a decision.
1. Flammable – This is definitely an advantage in that they can be melted down, however smoldering plastics can release toxic fumes into the environment.
2. Cost of Recycling – While recycling is a plus, recycling is a very costly endeavor.
3. Volume – In the United States 20% of our landfill is made up of plastics. As more products are being made of plastics, where will this lead us in the future?
4. Durability – This is an advantage as well as a disadvantage. Plastics are extremely durable, which means that they last a long time. Those plastics in the landfill will be there for years.
Plastics make our lives easier, however is their cost on the environment worth it? We can only hope that soon someone will invent a way to safely and cheaply melt and reuse plastics.
A plastic material is any of a wide range of synthetic or semi-synthetic organic amorphous solids[citation needed] used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce costs. Monomers of plastic are either natural or synthetic organic compounds.
The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their malleability, or plasticity during manufacture, that allows them to be cast, pressed, or extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and much more.
The common word plastic should not be confused with the technical adjective plastic, which is applied to any material which undergoes a permanent change of shape (plastic deformation) when strained beyond a certain point. Aluminum, for instance, is plastic in this sense, but not a plastic in the common sense; in contrast, in their finished forms, some plastics will break before deforming and therefore are not plastic in the technical sense.
There are two types of plastics: thermoplastics and thermosetting polymers. Thermoplastics will soften and melt if enough heat is applied; examples are polyethylene, polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE)[3]. Thermosets can melt and take shape once; after they have solidified, they stay solid.
Overview
Plastics can be classified by chemical structure, namely the molecular units that make up the polymer's backbone and side chains. Some important groups in these classifications are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics can also be classified by the chemical process used in their synthesis, such as condensation, polyaddition, and cross-linking.[4]
Other classifications are based on qualities that are relevant for manufacturing or product design. Examples of such classes are the thermoplastic and thermoset, elastomer, structural, biodegradable, and electrically conductive. Plastics can also be classified by various physical properties, such as density, tensile strength, glass transition temperature, and resistance to various chemical products.
Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their former uses.
The use of plastics is constrained chiefly by their organic chemistry, which seriously limits their hardness, density, and their ability to resist heat, organic solvents, oxidation, and ionizing radiation. In particular, most plastics will melt or decompose when heated to a few hundred degrees celsius.[5] While plastics can be made electrically conductive to some extent, they are still no match for metals like copper or aluminum.[citation needed] Plastics are still too expensive to replace wood, concrete and ceramic in bulky items like ordinary buildings, bridges, dams, pavement, and railroad ties.
Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are assumed to have infinite molecular weight. These chains are made up of many repeating molecular units, known as repeat units, derived from monomers; each polymer chain will have several thousand repeating units. The vast majority of plastics are composed of polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the backbone. (Some of commercial interests are silicon based.) The backbone is that part of the chain on the main "path" linking a large number of repeat units together. To customize the properties of a plastic, different molecular groups "hang" from the backbone (usually they are "hung" as part of the monomers before linking monomers together to form the polymer chain). This fine tuning of the properties of the polymer by repeating unit's molecular structure has allowed plastics to become such an indispensable part of twenty first-century world.
Some plastics are partially crystalline and partially amorphous in molecular structure, giving them both a melting point (the temperature at which the attractive intermolecular forces are overcome) and one or more glass transitions (temperatures above which the extent of localized molecular flexibility is substantially increased). The so-called semi-crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride), polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all thermosets.
Almost every market that you go today, you will see people carrying their shopping items in plastic bags. Right from food items to clothes to shoes, there is hardly any item that we do not use a plastic bag to carry. However, before stuffing your home with different styles, colors and shapes of plastic bags, have you every considered the dangers that are inherent in using them? No? Then, reading through this article is a must for you. Go through the following lines and explore the disadvantages of plastic bags. After reading them, we are sure that you will prefer sticking to paper bags and the like.
Dangers Of Using Plastic Bags
Environmental Damage
Plastic bags have been known to cause a lot of environmental damage. A single plastic bag can take up to 1000 years, to decay completely. This makes the bags stay in environments longer, in turn leading to great build-up on the natural landscape (much more than degradable materials like paper). In other words, the more plastic bags you use, the greater the chances of environmental damage.
Threat To Animal Life
As per Marrickville Council of Australia, as many as 100,000 whales, turtles and birds die have been reported to die every year, mainly because of plastic in their environment. Plastic bags not only have adverse effects on our natural habitats, but have also been found to be responsible for the death of many animals, mainly on account of the suffocation encountered on eating them.
Suffocation
Not only animals, infants and young children have also been reported to have lost their life, on account of plastic bags. Since plastic bags are thin and airtight as well, children often end up blocking their mouths and nostrils with them. In case they are not being monitored by an adult, this leads to suffocation and, in some cases, even death.
Pollution
Plastic bags are extremely durable. In case you are thinking of this as an advantage, just bring to mind an image of the huge landfill that you visited on the city outskirts, the other day. In most probability, majority of the rubbish present there will comprise of plastic bags only. In other words, plastic bags have led to a great increase in the pollution levels.
Fumes
Since plastic bags are not bio-degradable, the only way to get rid of them is to burn them up. Though lighting a match to them is easy, it has more than its fair share of disadvantages. The biggest of them is that smoldering plastics can release toxic fumes into the environment, in turn taking the air pollution to much higher levels.
Non-renewable
One of the main disadvantages of plastic bags is that they are not renewable. The reason behind this is that they are made of petrochemicals, a non-renewable source of energy. They can be recycled, but not as easily as paper bags. Plastic bags can last for as much as hundred of years. In other words, long after you are no more, the plastic bag used by you will be in existence.
Plastics are manufactured from petroleum. This brings a host of issues (destruction of habitat, extraction of crude oil, security issues from the volatile countries where oil is produced, processing of petroleum, chemical manipulation into various types of plastics). The manufacture involves many chemicals, many of which have not been sufficiently tested for their toxicological impact on humans or animals.
The final plastic product is often a chemical entity that in and of itself has had insufficient toxicological and ecotoxicological testing. An example would be PVC, forms of which are banned in Europe but exist widely in children's toys in America. Recent controversies over plastic bottles (many toxicologists recommending not re-using plastic water bottles and not storing food in tupperware) have highlighted the potential risks. Exacerbating the problem is that science is only now advancing to where it can detect plastic components in human blood and then trace concentrations and link them to human ailments and diseases.
The plastics industry itself often spins plastic and related plastic chemicals into a variety of products, some of which are hazardous and controversial (Teflon, PVC, Polyethylene, polystyrene, various silicones in body and hair care). Plastic-producing companies are often chemical companies or subsidiaries of chemical companies, both with poor track records when it comes to their adherence to regulatory compliance and their willingness to perform toxicological analysis on the products they make.
Plastics often leech component chemicals, including hazardous chemicals, through common temperature changes. It is for this reason that toxicologists do not recommend storing very cold foods in plastics or heating foods (microwaving especially) in plastics.
Plastics are durable materials. Thus, they are hard to eliminate once used and create tremendous waste. While some common plastics can be recycled (#1 and #2 plastics used in common soda and milk bottles), the vast majority cannot. They take up a lot of space in landfills and create air pollution when incinerated.
The Disadvantages of Plastic Skylights
Although plastic skylights are safer and sturdier than glass skylights, they do pose several long term disadvantages. Firstly, because they are made in single sheets, they can only be curved or bent in one area, which limits design options. Secondly, all plastics deteriorate in strength and light transmission as time passes, due to ultraviolet rays, heat and oxidation (and none can be entirely prevented). And finally, the life and service of plastic materials is highly unpredictable. Therefore choosing the plastics you will use for a plastic skylight requires much research and first hand knowledge. This is where Roof 101 can help – our contractors have worked with all kinds of plastics in plastic skylights, and their first hand experience could greatly assist you in reaching a decision.
An ocean is a major body of saline water
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface (~3.61 X 1014 m2) is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.
More than half of this area is over 3,000 metres (9,800 ft) deep. Average oceanic salinity is around 35 parts per thousand (ppt) (3.5%), and nearly all seawater has a salinity in the range of 30 to 38 ppt. Scientists estimate that 230,000 marine life forms of all types are currently known, but the total could be up to 10 times that number.
Overview
Though generally described as several 'separate' oceans, these waters comprise one global, interconnected body of salt water sometimes referred to as the World Ocean or global ocean. This concept of a continuous body of water with relatively free interchange among its parts is of fundamental importance to oceanography.
The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria. These divisions are (in descending order of size):
Pacific Ocean, which separates Asia and Australia from the Americas
Atlantic Ocean, which separates the Americas from Eurasia and Africa
Indian Ocean, which washes upon southern Asia and separates Africa and Australia
Southern Ocean, which, unlike other oceans, has no landmass separating it from other oceans and is therefore sometimes subsumed as the southern portions of the Pacific, Atlantic, and Indian Oceans, which encircles Antarctica and covers much of the Antarctic
Arctic Ocean, sometimes considered a sea of the Atlantic, which covers much of the Arctic and washes upon northern North America and Eurasia
The Pacific and Atlantic may be further subdivided by the equator into northern and southern portions. Smaller regions of the oceans are called seas, gulfs, bays, straits and other names.
Geologically, an ocean is an area of oceanic crust covered by water. Oceanic crust is the thin layer of solidified volcanic basalt that covers the Earth's mantle. Continental crust is thicker but less dense. From this perspective, the earth has three oceans: the World Ocean, the Caspian Sea, and Black Sea. The latter two were formed by the collision of Cimmeria with Laurasia. The Mediterranean Sea is at times a discrete ocean, because tectonic plate movement has repeatedly broken its connection to the World Ocean through the Strait of Gibraltar. The Black Sea is connected to the Mediterranean through the Bosporus, but the Bosporus is a natural canal cut through continental rock some 7,000 years ago, rather than a piece of oceanic sea floor like the Strait of Gibraltar.
Despite their names, smaller landlocked bodies of saltwater that are not connected with the World Ocean, such as the Aral Sea, are actually salt lakes.
Ocean and life
The ocean has a significant effect on the biosphere. Oceanic evaporation, as a phase of the water cycle, is the source of most rainfall, and ocean temperatures determine climate and wind patterns that affect life on land. Life within the ocean evolved 3 billion years prior to life on land. Both the depth and distance from shore strongly influence the amount and kinds of plants and animals that live there.
Physical properties
Further information: Sea water
The area of the World Ocean is 361×106 km2 (139×106 mi2) Its volume is approximately 1.3 billion cubic kilometres (310 million cu mi). This can be thought of as a cube of water with an edge length of 1,111 kilometres (690 mi). Its average depth is 3,790 metres (12,430 ft), and its maximum depth is 10,923 metres (6.787 mi) Nearly half of the world's marine waters are over 3,000 metres (9,800 ft) deep. The vast expanses of deep ocean (anything below 200 metres (660 ft) cover about 66% of the Earth's surface. This does not include seas not connected to the World Ocean, such as the Caspian Sea.
The total mass of the hydrosphere is about 1,400,000,000,000,000,000 metric tons (1.5×1018 short tons) or 1.4×1021 kg, which is about 0.023 percent of the Earth's total mass. Less than 3 percent is freshwater; the rest is saltwater, mostly in the ocean.
Color
Main article: Color of water
A common misconception is that the oceans are blue primarily because the sky is blue. In fact, water has a very slight blue color that can only be seen in large volumes. While the sky's reflection does contribute to the blue appearance of the surface, it is not the primary cause. The primary cause is the absorption by the water molecules' nuclei of red photons from the incoming light, the only known example of color in nature resulting from vibrational, rather than electronic, dynamics.
Glow
Sailors and other mariners have reported that the ocean often emits a visible glow, or luminescence, which extends for miles at night. In 2005, scientists announced that for the first time, they had obtained photographic evidence of this glow. It may be caused by bioluminescence.
Exploration
Main article: Ocean exploration
Map of large underwater features. (1995, NOAA)
Ocean travel by boat dates back to prehistoric times, but only in modern times has extensive underwater travel become possible.
The deepest point in the ocean is the Mariana Trench, located in the Pacific Ocean near the Northern Mariana Islands. Its maximum depth has been estimated to be 10,971 metres (35,994 ft) (plus or minus 11 meters; see the Mariana Trench article for discussion of the various estimates of the maximum depth.) The British naval vessel, Challenger II surveyed the trench in 1951 and named the deepest part of the trench, the "Challenger Deep". In 1960, the Trieste successfully reached the bottom of the trench, manned by a crew of two men.
Much of the ocean bottom remains unexplored and unmapped. A global image of many underwater features larger than 10 kilometres (6.2 mi) was created in 1995 based on gravitational distortions of the nearby sea surface.[citation needed]
Regions and depths
The major oceanic divisions
Oceanographers divide the ocean into regions depending on physical and biological conditions of these areas. The pelagic zone includes all open ocean regions, and can be divided into further regions categorized by depth and light abundance. The photic zone covers the oceans from surface level to 200 metres down. This is the region where photosynthesis can occur and therefore is the most biodiverse. Since plants require photosynthesis, life found deeper than this must either rely on material sinking from above (see marine snow) or find another energy source; hydrothermal vents are the primary option in what is known as the aphotic zone (depths exceeding 200 m). The pelagic part of the photic zone is known as the epipelagic. The pelagic part of the aphotic zone can be further divided into regions that succeed each other vertically according to temperature.
The mesopelagic is the uppermost region. Its lowermost boundary is at a thermocline of 12 °C (54 °F), which, in the tropics generally lies at 700–1,000 metres (2,300–3,300 ft). Next is the bathypelagic lying between 10-4 °C (43 °F), typically between 700–1,000 metres (2,300–3,300 ft) and 2,000–4,000 metres (6,600–13,000 ft) Lying along the top of the abyssal plain is the abyssalpelagic, whose lower boundary lies at about 6,000 metres (20,000 ft). The final zone includes the deep trenches, and is known as the hadalpelagic. This lies between 6,000–11,000 metres (20,000–36,000 ft) and is the deepest oceanic zone.
Along with pelagic aphotic zones there are also benthic aphotic zones. These correspond to the three deepest zones of the deep sea. The bathyal zone covers the continental slope down to about 4,000 metres (13,000 ft). The abyssal zone covers the abyssal plains between 4,000 and 6,000 m. Lastly, the hadal zone corresponds to the hadalpelagic zone which is found in the oceanic trenches. The pelagic zone can also be split into two subregions, the neritic zone and the oceanic zone. The neritic encompasses the water mass directly above the continental shelves, while the oceanic zone includes all the completely open water. In contrast, the littoral zone covers the region between low and high tide and represents the transitional area between marine and terrestrial conditions. It is also known as the intertidal zone because it is the area where tide level affects the conditions of the region.
More than half of this area is over 3,000 metres (9,800 ft) deep. Average oceanic salinity is around 35 parts per thousand (ppt) (3.5%), and nearly all seawater has a salinity in the range of 30 to 38 ppt. Scientists estimate that 230,000 marine life forms of all types are currently known, but the total could be up to 10 times that number.
Overview
Though generally described as several 'separate' oceans, these waters comprise one global, interconnected body of salt water sometimes referred to as the World Ocean or global ocean. This concept of a continuous body of water with relatively free interchange among its parts is of fundamental importance to oceanography.
The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria. These divisions are (in descending order of size):
Pacific Ocean, which separates Asia and Australia from the Americas
Atlantic Ocean, which separates the Americas from Eurasia and Africa
Indian Ocean, which washes upon southern Asia and separates Africa and Australia
Southern Ocean, which, unlike other oceans, has no landmass separating it from other oceans and is therefore sometimes subsumed as the southern portions of the Pacific, Atlantic, and Indian Oceans, which encircles Antarctica and covers much of the Antarctic
Arctic Ocean, sometimes considered a sea of the Atlantic, which covers much of the Arctic and washes upon northern North America and Eurasia
The Pacific and Atlantic may be further subdivided by the equator into northern and southern portions. Smaller regions of the oceans are called seas, gulfs, bays, straits and other names.
Geologically, an ocean is an area of oceanic crust covered by water. Oceanic crust is the thin layer of solidified volcanic basalt that covers the Earth's mantle. Continental crust is thicker but less dense. From this perspective, the earth has three oceans: the World Ocean, the Caspian Sea, and Black Sea. The latter two were formed by the collision of Cimmeria with Laurasia. The Mediterranean Sea is at times a discrete ocean, because tectonic plate movement has repeatedly broken its connection to the World Ocean through the Strait of Gibraltar. The Black Sea is connected to the Mediterranean through the Bosporus, but the Bosporus is a natural canal cut through continental rock some 7,000 years ago, rather than a piece of oceanic sea floor like the Strait of Gibraltar.
Despite their names, smaller landlocked bodies of saltwater that are not connected with the World Ocean, such as the Aral Sea, are actually salt lakes.
Ocean and life
The ocean has a significant effect on the biosphere. Oceanic evaporation, as a phase of the water cycle, is the source of most rainfall, and ocean temperatures determine climate and wind patterns that affect life on land. Life within the ocean evolved 3 billion years prior to life on land. Both the depth and distance from shore strongly influence the amount and kinds of plants and animals that live there.
Physical properties
Further information: Sea water
The area of the World Ocean is 361×106 km2 (139×106 mi2) Its volume is approximately 1.3 billion cubic kilometres (310 million cu mi). This can be thought of as a cube of water with an edge length of 1,111 kilometres (690 mi). Its average depth is 3,790 metres (12,430 ft), and its maximum depth is 10,923 metres (6.787 mi) Nearly half of the world's marine waters are over 3,000 metres (9,800 ft) deep. The vast expanses of deep ocean (anything below 200 metres (660 ft) cover about 66% of the Earth's surface. This does not include seas not connected to the World Ocean, such as the Caspian Sea.
The total mass of the hydrosphere is about 1,400,000,000,000,000,000 metric tons (1.5×1018 short tons) or 1.4×1021 kg, which is about 0.023 percent of the Earth's total mass. Less than 3 percent is freshwater; the rest is saltwater, mostly in the ocean.
Color
Main article: Color of water
A common misconception is that the oceans are blue primarily because the sky is blue. In fact, water has a very slight blue color that can only be seen in large volumes. While the sky's reflection does contribute to the blue appearance of the surface, it is not the primary cause. The primary cause is the absorption by the water molecules' nuclei of red photons from the incoming light, the only known example of color in nature resulting from vibrational, rather than electronic, dynamics.
Glow
Sailors and other mariners have reported that the ocean often emits a visible glow, or luminescence, which extends for miles at night. In 2005, scientists announced that for the first time, they had obtained photographic evidence of this glow. It may be caused by bioluminescence.
Exploration
Main article: Ocean exploration
Map of large underwater features. (1995, NOAA)
Ocean travel by boat dates back to prehistoric times, but only in modern times has extensive underwater travel become possible.
The deepest point in the ocean is the Mariana Trench, located in the Pacific Ocean near the Northern Mariana Islands. Its maximum depth has been estimated to be 10,971 metres (35,994 ft) (plus or minus 11 meters; see the Mariana Trench article for discussion of the various estimates of the maximum depth.) The British naval vessel, Challenger II surveyed the trench in 1951 and named the deepest part of the trench, the "Challenger Deep". In 1960, the Trieste successfully reached the bottom of the trench, manned by a crew of two men.
Much of the ocean bottom remains unexplored and unmapped. A global image of many underwater features larger than 10 kilometres (6.2 mi) was created in 1995 based on gravitational distortions of the nearby sea surface.[citation needed]
Regions and depths
The major oceanic divisions
Oceanographers divide the ocean into regions depending on physical and biological conditions of these areas. The pelagic zone includes all open ocean regions, and can be divided into further regions categorized by depth and light abundance. The photic zone covers the oceans from surface level to 200 metres down. This is the region where photosynthesis can occur and therefore is the most biodiverse. Since plants require photosynthesis, life found deeper than this must either rely on material sinking from above (see marine snow) or find another energy source; hydrothermal vents are the primary option in what is known as the aphotic zone (depths exceeding 200 m). The pelagic part of the photic zone is known as the epipelagic. The pelagic part of the aphotic zone can be further divided into regions that succeed each other vertically according to temperature.
The mesopelagic is the uppermost region. Its lowermost boundary is at a thermocline of 12 °C (54 °F), which, in the tropics generally lies at 700–1,000 metres (2,300–3,300 ft). Next is the bathypelagic lying between 10-4 °C (43 °F), typically between 700–1,000 metres (2,300–3,300 ft) and 2,000–4,000 metres (6,600–13,000 ft) Lying along the top of the abyssal plain is the abyssalpelagic, whose lower boundary lies at about 6,000 metres (20,000 ft). The final zone includes the deep trenches, and is known as the hadalpelagic. This lies between 6,000–11,000 metres (20,000–36,000 ft) and is the deepest oceanic zone.
Along with pelagic aphotic zones there are also benthic aphotic zones. These correspond to the three deepest zones of the deep sea. The bathyal zone covers the continental slope down to about 4,000 metres (13,000 ft). The abyssal zone covers the abyssal plains between 4,000 and 6,000 m. Lastly, the hadal zone corresponds to the hadalpelagic zone which is found in the oceanic trenches. The pelagic zone can also be split into two subregions, the neritic zone and the oceanic zone. The neritic encompasses the water mass directly above the continental shelves, while the oceanic zone includes all the completely open water. In contrast, the littoral zone covers the region between low and high tide and represents the transitional area between marine and terrestrial conditions. It is also known as the intertidal zone because it is the area where tide level affects the conditions of the region.
Sunday, June 27, 2010
My Experience As A Blood Donator
I've always wanted to donate blood, but it just so happen that whenever I was near a blood donation booth, I was either having stressed out or need to study for exam, the excuses go on and on. It is embarrassing to admit that my first time donating blood
I was supposed to donate blood for my sister .My sister had medical emergency the other day. She needed blood. This time I passed the screening and I was able to donate blood for her.The hospital was requesting that the blood consumed by the patient be replenished, regardless of blood type.
Here are the steps of the blood donation:
Step 1: Interview Data Sheet
At the hospital's Blood Center, I were asked to fill out a Blood Donor Interview Data Sheet. Many of the questions pertained to health status and medical family history.
Step 2: Health interview & brief physical examination
Nurses took my respective blood pressure, weight, temperature and pulse. Then a doctor interviewed me based on the info sheet I submitted.
When the doctor found out that I just finished my period, he told me that it was best to wait for another week before donating blood. I was a eligible for blood donation at that time.. A small amount of blood was extracted from me to test hemoglobin level to ensure that he was eligible to donate. After a few minutes, I can donate blood.
Step 3: Blood donation
I was sit down on a reclining chair. The medical technician initially inserted a sterile needle into my right arm but had some difficulty locating the proper vein. I found out that it's harder to draw blood on some people. The medical technician was able to draw blood on my left arm. It took around 10 minutes to collect one pint of blood. After the draw was complete, the needle was gently removed and my arm bandaged. I rested for a few minutes.I learned that for every 'bag' of blood used by the patient, the hospital requires three 'bags' of blood in exchange, regardless of blood type. The blood are stored in this special blood bank refrigerator. My sister is doing much better now.
I was supposed to donate blood for my sister .My sister had medical emergency the other day. She needed blood. This time I passed the screening and I was able to donate blood for her.The hospital was requesting that the blood consumed by the patient be replenished, regardless of blood type.
Here are the steps of the blood donation:
Step 1: Interview Data Sheet
At the hospital's Blood Center, I were asked to fill out a Blood Donor Interview Data Sheet. Many of the questions pertained to health status and medical family history.
Step 2: Health interview & brief physical examination
Nurses took my respective blood pressure, weight, temperature and pulse. Then a doctor interviewed me based on the info sheet I submitted.
When the doctor found out that I just finished my period, he told me that it was best to wait for another week before donating blood. I was a eligible for blood donation at that time.. A small amount of blood was extracted from me to test hemoglobin level to ensure that he was eligible to donate. After a few minutes, I can donate blood.
Step 3: Blood donation
I was sit down on a reclining chair. The medical technician initially inserted a sterile needle into my right arm but had some difficulty locating the proper vein. I found out that it's harder to draw blood on some people. The medical technician was able to draw blood on my left arm. It took around 10 minutes to collect one pint of blood. After the draw was complete, the needle was gently removed and my arm bandaged. I rested for a few minutes.I learned that for every 'bag' of blood used by the patient, the hospital requires three 'bags' of blood in exchange, regardless of blood type. The blood are stored in this special blood bank refrigerator. My sister is doing much better now.
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