Heat Engines (essays by our students)

03.04.2020

Heat engines freed a person from hard physical labor; they perform work hundreds and thousands of times more than that which a person could have done without machines. Most of the engines on Earth are heat engines. Heat engines are used on all the main types of modern transport: on automobile-piston internal combustion engines, on water-internal-combustion engines and steam turbines, on the railway-diesel locomotives, in aviation-piston, turbojet, and jet engines. Common to all heat engines is that they increase their internal energy by burning fuel, with the subsequent conversion of internal energy into mechanical energy. The main component of the exhausts of internal combustion engines (except for noise) - carbon monoxides, that are dangerous for humans and animals.

 

They cause poisoning of varying degrees depending on concentration. It is proved that road transport on Earth is one of the main pollutants in the atmosphere. The average car emits per year:

• 135 kilograms of carbon monoxide (CO);

• 25 kilograms of nitrogen oxides (NO, NO2);

• 200 kilograms of hydrocarbons (colorless vapors);

• From 7 to 10 kg of benzopyrene;

• 4 kilograms of sulfur dioxide (SO2)

• 5-8 kg of rubber dust;

• 5 types of heavy metals: lead (Pb), cadmium (Cd), vanadium (V), beryllium (Be), chromium (Cr).

All substances polluting the air to a greater or lesser extent hurt human health. These substances enter the human body through the respiratory system. Respiratory organs suffer from contamination since about 50% of the particles that enter the lungs are deposited in them. Here are examples of the effects of harmful substances on the human body.

 

1. Carbon monoxide (CO). CO can accumulate in the body. CO is an aggressive gas that combines with hemoglobin. At the same time, visual acuity deterioration, some psychomotor functions of the brain are disturbed, the activity of the heart and lungs changes, headaches, drowsiness, cramping, and respiratory disorders appear.

2. Sulfur dioxide (SO2 and SO3) leads to difficulty breathing and lung diseases, affects the human respiratory system, causes cough, chest pain.

3. Nitrogen oxides (NO, NO2) irritate and cause inflammation of the eyes, and in combination with ozone irritate the nasopharynx, lead to chest spasms, and at high concentrations cause a strong cough, irritating the respiratory tract. The operation of thermal machines has a negative impact on the environment, which leads to several environmental problems:

• When internal combustion engines are operating, the combustion of 1 kg of gasoline requires 2.5 kg of oxygen, which is taken from the atmosphere. The result is a decrease in oxygen in the air.

• An increase in CO2 in the atmosphere enhances the greenhouse effect.

• Air pollution by nitrogen and sulfur oxides leads to acid rain.

• Lead contamination leads to the poisoning of the soil, water, and atmosphere.

• During the operation of heat engines (ICE), groundwater is contaminated with waste engine oil, which leads to the problem of clean fresh water.

• Huge fuel consumption for the operation of heat engines leads to a reduction of inexhaustible natural resources (oil, gas).

• During the extraction, transportation, and refining of oil, the biosphere is contaminated with oil products, which leads to the problem of the oceans.

• The increase in the atmosphere of nitrogen oxides generated during the flight of supersonic planes and rockets at high altitude destroys the ozone layer, which protects the Earth from dangerous ultraviolet solar radiation.

Transport is becoming one of the main sources of environmental pollution. Unfortunately, mankind is not able to abandon the use of heat engines. To consume less fuel and to fight against the negative consequences of using heat engines is to increase the efficiency of energy use and switch to energy-saving technologies. Today, more electric locomotives are replacing conventional trains; battery cars are becoming more popular. Energy-saving technologies are being introduced into the industry.

 

Макарова Ева, 10а класс

 

(оригинальность: 98,39%)

Nowadays many people don’t pay attention to environmental problems. While caring about daily difficulties that we face in our life’s journey, we forget about place, which has given birth to all people, which supplies us with different resources, and gives us a chance to live a happy life. People ignore the fact that Earth tries to send us “messages” that it is suffering from things that we do. These messages are: floods, hurricanes, storms, and other natural disasters. Even after this people don’t want to think about what we do and how to avoid environmental problems. For the last few years climate has changed and not in a good way. Our planet is overpopulated and every day each person slowly helps to kill our “home” even when throws some rubbish on the ground. The climate change is the cause of irresponsibility and indifference of people. We don’t usually think about consequences, but when we see them, only then people start to think what we have done. For example, the result of man’s intervention with environment is a global warming. This process makes the surface of the planet to heat up. If the warming continues, the sea level will be even higher than now and there are going to be many floods. All cities near the shores will be covered with water and no one will survive. Cars, factories produce a huge amount of carbon dioxide, making its concentration in atmosphere very big, which can lead to global warming. To avoid this problem we need to increase the number of forests, which enrich planet with oxygen and also we need to use solar and wind power.

 

I want to add that due to activity of people like burning of fossil fuels, Greenhouse effect is caused. The result is an increase in ejection of harmful greenhouse gasses such as carbon dioxide, carbon monoxide, sulfides and others. Its consequence is the rise in temperature, which can lead to melting of our Polar poles. The rapid growth of road transport has increased the exhaust emissions. If you refer to the laws of thermodynamics, you know that the production of useful work is impossible without the removal of large amounts of heat into the environment, which increases the average temperature on our planet. That’s why if we gave up heat engines, environmental system would become healthier, there won’t be so many harmful gases in the atmosphere and global problems would become solvable. In conclusion I want to say that people need to think about nature and do everything to save our planet, because without it we wouldn’t be able to live. Only we can choose what measures to take in order to protect Earth and I hope we will choose right ones. (This work can be published in the public domain)

 

Черных Софья, 10в класс

 

(оригинальность 96,76%)

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