Electronic noise
Electronic noise exists in all circuits and devices as a result of thermal noise, also referred to as Johnson Noise. Semiconductor devices can also contribute flicker noise and generation-recombination noise. In any electronic circuit, there exist random variations in current or voltage caused by the random movement of the electrons carrying the current as they are jolted around by thermal energy. Lower temperature results in lower thermal noise. This same phenomenon limits the minimum signal level that any radio receiver can usefully respond to, because there will always be a small but significant amount of thermal noise arising in its input circuits. This is why radio telescopes, which search for very low levels of signal from stars, use front-end low-noise amplifier circuits, usually mounted on the aerial dish, and cooled with liquid nitrogen.
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In many of these areas, the special case of thermal noise arises, which sets a fundamental lower limit to what can be measured or signaled and is related to basic physical processes at the molecular level described by well-established thermodynamics considerations, some of which are expressible by relatively well known simple formulae.
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EMOTIONAL ABUSE
What is Emotional Abuse? Abuse is any behavior that is designed to control and subjugate another human being through the use of fear, humiliation, intimidation, guilt, coercion, manipulation etc. Emotional abuse is any kind of abuse that is emotional rather than physical in nature. It can include anything from verbal abuse and constant criticism to more subtle tactics, such as repeated disapproval or even the refusal to ever be pleased.
Emotional abuse is like brain washing in that it systematically wears away at the victim's self-confidence, sense of self-worth, trust in their own perceptions, and self-concept. Whether it is done by constant berating and belittling, by intimidation, or under the guise of "guidance," "teaching", or "advice," the results are similar. Eventually, the recipient of the abuse loses all sense of self and remnants of personal value. Emotional abuse cuts to the very core of a person, creating scars that may be far deeper and more lasting that physical ones. In fact there is research to this effect. With emotional abuse, the insults, insinuations, criticism and accusations slowly eat away at the victim's self-esteem until she is incapable of judging the situation realistically. She has become so beaten down emotionally that she blames herself for the abuse. Her self-esteem is so low that she clings to the abuser. Emotional abuse victims can become so convinced that they are worthless that they believe that no one else could want them. They stay in abusive situations because they believe they have nowhere else to go. Their ultimate fear is being all alone.
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Unit 3. HAZARDS, RISKS, OUTCOMES
HAZARD ANALYSIS
A hazard analysis is used to characterize the elements of risk. A hazard analysis is one tool within the discipline of system safety engineering. The results of a hazard analysis will drive the methods used for development of a system, both hardware and software.
A hazard is defined as a "Condition, event, or circumstance that could lead to or contribute to an unplanned or undesirable event." Seldom does a single hazard cause an accident. More often, an accident occurs as the result of a sequence of causes. A hazard analysis will consider system state, for example operating environment, as well as failures or malfunctions.
While in some cases safety risk can be eliminated, in most cases a certain degree of safety risk must be accepted. In order to quantify expected accident costs before the fact, the potential consequences of an accident, and the probability of occurrence must be considered. Assessment of risk is made by combining the severity of consequence with the likelihood of occurrence in a matrix. Risks that fall into the "unacceptable" category (e.g., high severity and high probability) must be mitigated by some means to reduce the level of safety risk.
Severity definitions
Severity | Definition |
Catastrophic | Results in multiple fatalities and/or loss of the system |
Hazardous | Reduces the capability of the system or the operator ability to cope with adverse conditions to the extent that there would be: · Large reduction in safety margin or functional capability · Crew physical distress/excessive workload such that operators cannot be relied upon to perform required tasks accurately or completely · Serious or fatal injury to small number of occupants of aircraft (except operators) · Fatal injury to ground personnel and/or general public |
Major | Reduces the capability of the system or the operators to cope with adverse operating conditions to the extent that there would be: · Significant reduction in safety margin or functional capability · Significant increase in operator workload · Conditions impairing operator efficiency or creating significant discomfort · Physical distress to occupants of aircraft (except operator) including injuries · Major occupational illness and/or major environmental damage, and/or major property damage |
Minor | Does not significantly reduce system safety. Actions required by operators are well within their capabilities. Include: · Slight reduction in safety margin or functional capabilities · Slight increase in workload such as routine flight plan changes · Some physical discomfort to occupants or aircraft (except operators) · Minor occupational illness and/or minor environmental damage, and/or minor property damage |
No Safety Effect | Has no effect on safety |
Likelihood of occurrence
Likelihood | Definition |
Probable | · Qualitative: Anticipated to occur one or more times during the entire system/operational life of an item. · Quantitative: Probability of occurrence per operational hour is greater than |
Remote | · Qualitative: Unlikely to occur to each item during its total life. May occur several times in the life of an entire system or fleet. · Quantitative: Probability of occurrence per operational hour is less than |
Extremely Remote | · Qualitative: Not anticipated to occur to each item during its total life. May occur a few times in the life of an entire system or fleet. · Quantitative: Probability of occurrence per operational hour is less than |
Extremely Improbable | · Qualitative: So unlikely that it is not anticipated to occur during the entire operational life of an entire system or fleet. · Quantitative: Probability of occurrence per operational hour is less than |
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Unit 4. NATURAL HAZARDS.
TROPICAL ACTIVITY
Tropical activity in general consists of large air masses several hundred miles across with low pressure at the centre and with winds blowing around the centre in either a clockwise direction (southern hemisphere) or counterclockwise (northern hemisphere). Precipitation arises when a warm front is formed by an advancing mass of warm air, which moves up an inclined surface of retreating cold air and is chilled in the process of being lifted up resulting in rainfall.
The Great Sandy Desert has nearly all its rain during from monsoonal thunderstorms or the occasional tropical cyclone rain depression. Thunderstorms occur on an average of 20–30 days annually through most of the area. Although the desert has fairly high precipitation rates, due to the high rates of evaporation, this area remains an arid environment with vast areas of sands.
Other areas of the world which see these rare precipitation events in deserts are northwest Mexico, the southwestern United States, and southwest Asia. In North America, the Sonoran and Chihuahuan Deserts have received some tropical rainfall in the last 10 years. Tropical activity is rare in all deserts, but what rain does arrive there is important to the existence of the delicate ecosystem.
Raindrops have sizes ranging from 0.1 to up to approximately 9 mm (0.004 to 0.4 in) mean diameter, above which they tend to break up. Smaller drops are called cloud droplets, and their shape is spherical. As a raindrop increases in size, its shape becomes more oblate, with its largest cross-section facing the oncoming airflow. Contrary to the cartoon pictures of raindrops, their shape does not resemble a teardrop. High intensity storms are likely to be of short duration and low intensity storms can have a long duration. We can expect a less intense rainfall over a large area than we can over a small area.
The likelihood or probability of an event with a specified intensity and duration, is called the return period or frequency. The intensity of a storm can be predicted for any return period and storm duration, from charts based on historic data for the location.
Frequency of flooding. There is no way of telling when the next flood will arrive or how big it will be, but past flooding events can help provide some information as to what to expect. The term “1 in 10 year storm” describes a rainfall event which is rare and is only likely to occur once every 10 years, so it has a 10% likelihood any given year. The amount of rain which will fall will be greater and cause the flooding to be worse than for a 1 in 1 year event. The term “1 in 100 year storm” (see also 100-year flood) describes a rainfall event which is extremely rare and which will occur with a likelihood of only once in a century, so has a 1% likelihood in any given year. The amount of rain which will fall will be extreme and cause far greater flooding to be worse than for a 1 in 1 year event. As with all “probability” events, it is still possible to have multiple “1 in 100 Year Storms” in the same year.
A blizzard is a severe winter storm condition characterized by low temperatures, strong winds, and heavy blowing snow. A drought is an abnormally dry period when there is not enough water to support agricultural, urban or environmental water needs. Extended droughts can result in deaths by starvation or disease, and can result in wildfires. Scientists warn that global warming may result in more extensive droughts in coming years.
A hailstorm is a natural hazard where a thunderstorm produces numerous hailstones which damage the location in which they fall. Hailstorms can be especially devastating to farm fields, ruining crops and damaging equipment.
A heat wave is a hazard characterized by heat which is considered extreme and unusual in the area in which it occurs. Heat waves are rare and require specific combinations of weather events to take place, and may include temperature inversions, katabatic winds, or other phenomena. There is potential for longer term events causing global warming, including stadial events (the opposite to glacial 'ice age' events), or through human induced climatic warming.
Hurricane Katrina, tropical cyclone, and typhoon are different names for the same phenomenon: a cyclonic storm system that forms over the oceans. It is caused by evaporated water that comes off of the ocean and becomes a storm. The Coriolis Effect causes the storms to spin, and a hurricane is declared when this spinning mass of storms attains a wind speed greater than 74 mph.
Hurricane is used for these phenomena in the Atlantic and eastern Pacific Oceans, tropical cyclone in the Indian, typhoon in the western Pacific.
An ice age is a geologic period, but could also be viewed in the light of a catastrophic natural hazard, since in an ice age, the climate all over the world would change and places which were once considered habitable would then be too cold to permanently inhabit. A side effect of an ice age could possibly be a famine, caused by a worldwide drought.
An ice storm is a particular weather event in which precipitation falls as ice, due to atmosphere conditions Luis Mi. Ruiz. A tornado is a natural disaster resulting from a thunderstorm. Tornadoes are violent, rotating columns of air which can blow at speeds between 50 and 300 mph, and possibly higher. Tornadoes can occur one at a time, or can occur in large tornado outbreaks along squall lines or in other large areas of thunderstorm development. Waterspouts are tornadoes occurring over tropical waters in light rain conditions.
A wildfire is an uncontrolled fire burning in wildland areas. Common causes include lightning and drought but wildfires may also be started by human negligence or arson. They can be a threat to those in rural areas and also wildlife. Wildfires can also produce ember attacks, where floating embers set fire to buildings at a distance from the fire itself.
Famine is a social and economic crisis that is commonly accompanied by widespread malnutrition, starvation, epidemic disease and increased mortality. Although some famines occur - or are aggravated - by natural factors, it can and often is a result of economic or military policy that deprives people of the food that they require to survive.
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Precipitation arises when a warm front is formed by an advancing mass of warm air, which moves up an inclined surface of retreating cold air and is chilled in the process of being lifted up resulting in rainfall.
There is no way of telling when the next flood will arrive or how big it will be, but past flooding events can help provide some information as to what to expect.
There is potential for longer term events causing global warming, including stadial events (the opposite to glacial 'ice age' events), or through human induced climatic warming.
Although some famines occur - or are aggravated - by natural factors, it can and often is a result of economic or military policy that deprives people of the food that they require to survive.
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Unit 5. MAN-MADE HAZARDS
2009 SAYANO-SHUSHENSKAYA HYDROELECTRIC POWER STATION ACCIDENT
Sayano–Shushenskaya hydroelectric power station is located on the Yenisei River, near Sayanogorsk in Khakassia, Russia. Before the accident, it was the largest power plant in Russia and the sixth-largest hydroelectric plant in the world, by average power generation.
The 2009 Sayano–Shushenskaya hydroelectric power station accident occurred at 00:13 GMT on 17 August 2009, (08:13 AM local time) when an explosion brought down the ceiling of the Sayano–Shushenskaya hydroelectric power station's turbine hall, leading to the flooding of the turbine hall and engine room. At the same time, an alarm was received at the power station's main control panel, and the power output fell to zero, resulting in a local blackout. The steel gates to the water intake pipes were closed manually at 9:20. The emergency diesel generator was started at 11:32. At 11:50, the opening of spillway gates was started. The opening of all 11 spillway gates was finished at 13:07. As of 30 August 2009 (2009 -08-30)[update], 72 people have been found dead and 3 were still missing, presumably dead. The cause of the accident is still being investigated.
Nine out of the ten turbines were operating at the time, with a total output 4,400 MW. Turbine № 6 was undergoing scheduled maintenance, but was ready for a restart. In addition to turbine № 2, turbines № 7 and 9 also suffered severe damage and were partly destroyed, while the turbine room roof and ceilings fell on and caused a serious damage to turbines № 1 and 3, with slight damage to turbines № 4, 5, 8, and 10. Water immediately flooded the engine and turbine rooms and caused a transformer explosion. Transformers № 1 and 2 were destroyed, while transformers № 3, 4, and 5 were left in satisfactory condition. Other damage was also severe as the machinery hall was destroyed, including the roof, ceilings, and floor.
Power generation from the station ceased completely following the incident, with the resulting blackout in residential areas being alleviated by diverting power from other plants. Aluminium smelters in Sayanogorsk and Khakassia were completely cut off from the grid before power supplies were replaced using alternate power sources. Power to blacked out areas was fully restored by 19 August 2009. It is expected that electricity prices will have to increase after the disaster. Environmental impact
The accident has a severe environmental impact as the explosion caused an oil spill, releasing at least 40 tonnes of transformer oil which spread over 80 km (50 mi) downstream of Yenisei. The oil spill during the approximately 2-3 hour cutoff of river flow when all the gates of the dam were closed, killed 400 tons of cultivated trout in two riverside fisheries, with its impact on wildlife as yet unassessed. By 19:00 local time on 19 August 2009, the 15 km-long spill had reached Ust-Abakan, where it was cordoned off with floating barriers and chemical sorbents. The oil spill was fully removed by 25 August 2009.
After the accident, the spillway was regulated to decrease the water level of reservoir by 3 to 5 centimetres (1.2 to 2.0 in) per day. Flood water was pumped out from the engine room on 24 August 2009. The search and rescue operation was completed on 29 August 2009.
The exact cause of the accident has not yet been announced; the official report will be published by the end of September 2009. According to the preliminary information by the Federal Environmental, Technological and Atomic Supervisory Service (Rostekhnadzor), the cause was a combination of several technological factors. Terrorist attack and human factor theories have been ruled out. Also, the hydraulic pressure surge as a possible cause of the accident has been excluded by Rostekhnadzor. Failure of turbine № 2 or of its control system are the remaining scenarios under investigation. In the media, defective turbines and a rise in pressure in the pipes are speculated to be possible causes.
The plant is expected to restart its operations within 1 to 1½ months, while replacement of damaged turbines will take up to four years.
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Unit 6. FACTORS THREATENING THE ENVIRONMENT
DEPLETION OF THE OZONE LAYER
The ozone layer, a thin band in the stratosphere (layer of the upper atmosphere), serves to shield Earth from the Sun's harmful ultraviolet rays. In the 1970s, scientists discovered that chlorofluorocarbons (CFCs)-chemicals used in refrigeration, air-conditioning systems, cleaning solvents, and aerosol sprays – destroy the ozone layer. CFCs release chlorine into the atmosphere; chlorine, in turn, breaks down ozone molecules. Because chlorine is not affected by its interaction with ozone, each chlorine molecule has the ability to destroy a large amount of ozone for an extended period of time. The consequences of continued depletion of the ozone layer would he dramatic. Increased ultraviolet radiation would lead to a growing number of skin cancers and cataracts and also reduce the ability of immune systems to respond to infection. Additionally, growth of the world's oceanic plankton, the base of most marine food chains, would decline. Plankton contains photosynthetic organisms that break down carbon dioxide. If plankton populations decline, it may lead to increased carbon dioxide levels in the atmosphere and thus to global warming. Recent studies suggest that global warming, in turn, may increase the amount of ozone destroyed. Even if the manufacture of CFCs is immediately banned, the chlorine already released into the atmosphere will continue to destroy the ozone layer for many decades.
In 1987, an international pact called the Montreal Protocol on Substances that Deplete the Ozone Layer set specific targets for all nations to achieve in order to reduce emissions of chemicals responsible for the destruction of the ozone layer. Many people had hoped that this treaty would cause ozone loss to peak and begin to decline by the year 2000. In fact, in the fall of 2000 the hole in the ozone layer over Antarctica was the largest ever recorded. The hole the following year was slightly smaller, leading some to believe that the depletion of ozone had stabilized. Even if the most stringent prohibitions against CFCs are implemented, however, scientists expect that it will take at least 50 more years for the hole over Antarctica to close completely.
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In the 1970s, scientists discovered that chlorofluorocarbons (CFCs)-chemicals used in refrigeration, air-conditioning systems, cleaning solvents, and aerosol sprays – destroy the ozone layer.
In 1987, an international pact called the Montreal Protocol on Substances that Deplete the Ozone Layer set specific targets for all nations to achieve in order to reduce emissions of chemicals responsible for the destruction of the ozone layer.
Unit 7. CLIMATE CHANGE. GLOBAL WARMING
Like the glass panes in a greenhouse, certain gases in the Earth's atmosphere permit the Sun's radiation to heat Earth. At the same time, these gases retard the escape into space of the infrared energy radiated back out by Earth. This process is referred to as the greenhouse effect. These gases, primarily carbon dioxide, methane, nitrous oxide, and water vapor, insulate Earth's surface, helping to maintain warm temperatures. Without these gases Earth would be a frozen planet with an average temperature of about -18 °C (about 0 °F) instead of a comfortable 15 °C (59 °F). If the concentration of these gases rises, they trap more heat within the atmosphere, causing worldwide temperatures to rise.
Within the last century, the amount of carbon dioxide in the atmosphere has increased dramatically, largely because people burn vast amounts of fossil fuels - coal and petroleum and its derivatives. Average global temperature also has increased by about 0.6 Celsius degrees (2.4 Fahrenheit degree) within the past century. Atmospheric scientists have found that at least half of that temperature increase can be attributed to human activity. They predict that unless dramatic action is taken, global temperature will continue to rise by 1.4 to 5.8 Celsius degrees (2,5 to 10,4 Fahrenheit degrees) over the next century. Although such an increase may not seem like a great difference, during the last ice age the global temperature was only 2.2 Celsius degrees (4 Fahrenheit degrees) cooler than it is presently. The consequences of such a modest increase in temperature may be devastating. Already scientists have detected a 40 percent reduction in the average thickness of Arctic ice. Other problems that may develop include a rise in sea levels that will completely inundate a number of low-lying island nations and flood many coastal cities, such as New York and Miami. Many plant and animal species will probably be driven into extinction, agriculture will be severely disrupted in many regions, and the frequency of severe hurricanes and droughts will likely increase.
The geographic North Pole was last covered with water about 50 million years ago during the early part of the present Cenozoic Era.
The global view of the Arctic Ocean, captured using advanced radar that sees through all weather conditions, is enabling researchers to determine how global warming may be affecting the Polar Ice Cap. The Arctic sea ice is providing clues to the Earth's overall climatic condition. During the Cenozoic Era, the continents that formed Pangea, the super continent, had begun to move into their present positions. As these continents drifted northward, they formed the shoreline of the Arctic Ocean, which lies directly over and around the geographic North Pole. About 50 million years ago, the Arctic Ice Cap formed over the Arctic Ocean, virtually covering the entire sea with a sheet of ice. As the continents continued to move, climatic changes brought about by shifts in water and air currents caused the Earth to gradually cool down. This created the glaciers that mostly dominated the land masses about 10,000 to 1.8 million years ago, and that still exist today on Greenland. The same climatic conditions that created the glaciers also formed the Arctic Ice Cap. Yet the ice sheet covering the Arctic Ocean rests directly on top of the ocean instead of land, and it has remained relatively stable and frozen since it was formed. The Arctic Ice Cap is shrinking dramatically. Since the 1950s, when data was first collected on the Arctic, the ice cap has lost nearly 22 % of its volume. It is projected that in another 50 years, nearly half of the Arctic Ice Cap will be gone.
So what is going on? We know that the Arctic Ice Cap, frozen for 50 million years, is melting. We also know that above normal Arctic temperatures from the ocean water to the air currents account for the melting. Global warming is real, and the melting of the Arctic Ice Cap is one of its symptoms.
Scientists have determined that the Earth's surface temperature has increased an average of 1° F since the beginning of the 20th century, which is enough to trigger significant global climatic changes.
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Unit 8. NATURAL AND MAN-MADE DISASTERS
STAMPEDE
A stampede is an act of mass impulse among herd animals or a crowd of people in which the herd (or crowd) collectively begins running with no clear direction or purpose. Stampedes are believed to originate from biological responses in the brains and endocrine systems of herd animals. The response is believed to have evolved to help animals escape predators.
A large stampede will frequently eliminate anything in its path. In farmed animals, herd managers, sometimes called cowboys, attempt to turn the moving herd into itself, so that it runs in circles rather than self-destructing by running over a cliff or into a river, or from damaging human life or property by overrunning human settlements.
Specific animals associated with stampede behaviour are cattle, elephants, Blue Wildebeests, wild horses and humans.
Human stampedes. The term stampede, also known as a crush or trampling, commonly describes a sudden rush of a crowd of people, usually resulting in many injuries and death from suffocation and trampling. Human stampedes most often occur during religious pilgrimages, professional sporting and music events. They also often occur in times of mass panic, as a result of a fire or explosion, as people try to get away.
The annual Muslim Hajj in Mecca, Saudi Arabia, which is attended by millions of pilgrims, has increasingly suffered from stampedes and other disasters, even as authorities have constructed new walkways and instituted other traffic controls to prevent them.
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Stampedes are believed to originate from biological responses in the brains and endocrine systems of herd animals.
In farmed animals, herd managers, sometimes called cowboys, attempt to turn the moving herd into itself, so that it runs in circles rather than self-destructing by running over a cliff or into a river, or from damaging human life or property by overrunning human settlements.
The annual Muslim Hajj in Mecca, Saudi Arabia, which is attended by millions of pilgrims, has increasingly suffered from stampedes and other disasters, even as authorities have constructed new walkways and instituted other traffic controls to prevent them.
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