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The pH of water is 7. It is considered to be neutral. Any
substance having a pH higher than 7 is considered to be acidic
and any substance having a pH lower than 7 is considered to
be basic.
In order homeostasis to be maintained in the human
body, body fluids (including blood) need to have a relatively
constant pH.
5) Carbohydrates Carbohydrates are the major source of
energy for most cells. They can be broken down in the cells in
order energy to be released.
Composition: carbon, hydrogen, and oxygen in a ratio
twice as much hydrogen as oxygen (example: CH2O, but they
can be more complex).
6) Fats Fats are molecules that are rich in energy and are
a source of food reserve and long-term fuel. They are stored in
the organism in the form of neutral fats or triglyceride.
Each fat molecule is composed of glycerol and fatty
acids.
7) Steroids These are fat-soluble compounds composed
of four bonded carbon rings, consisting of 17 carbons.
Examples: cholesterol, male and female sex hormones, etc.)
Steroid hormones help regulate certain phases of
metabolism in the body such as puberty, menopause, etc.
8) Proteins These organic compounds compose most of
the tissues of the body. They contain carbon, hydrogen,
oxygen, nitrogen (sometimes sulfur), phosphorus, and iron.
Proteins form enzymes that control chemical activity
(during the break-down of food molecules in the stomach),
protect us
against diseases in the form of antibodies, carry oxygen
throughout the body, make up some of the hormones, express
genetic information, and serve as indicators.
9) Amino acids Amino acids are the basic building units
of proteins. They always contain an amino group (NH2) at
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one end of the molecule and a carboxyl group at the other. An
amino acid contains one variable component. They may occur
in different chemical combinations.
That this is not all that can be said about body
chemistry. There are introduced the main organic compounds
in human body, but there are a lot more compounds.
NITROGEN OXIDES EMISSIONS FROM
DIESEL ENGINES
Master: Supervisor:
Omarova Gunay sen.teach. S.U.Verdiyeva
I year, group A3337
Diesel engines have high efficiency, durability, and
reliability together with their low-operating cost. These
features make them the most preferred engines especially for
heavy-duty vehicles. In addition to the widespread use of these
engines with many advantages, they play an important role in
environmental pollution problems. Many researches have been
carried out on both diesel exhaust pollutant emissions and after
treatment emission control technologies. This presentation
reviews the exhaust gas recirculation (EGR) method for
reducing NOx emissions from diesel engines.
The main problem areas for diesel engines are emissions
of nitrogen oxides and particulates, and these two pollutants are
traded against each other in many aspects of engine design.
Very high temperatures in the combustion chamber help reduce
the emission of soot but produce higher levels of nitric oxide.
The aim is to reduce emission of NOx by reducing need for
high temperature since NOx are created mostly due to
mechanisms that happen at high temperatures.
Since NOx
content in exhaust of diesel engine has the highest percentage
in the pollutant emissions, among the emission control systems
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of diesel engines, most researches and studies have been
carried out on reduction of NOx emissions. For the researches
so far, exhaust gas recirculation (EGR) is the most focused
technologies to eliminate the NOx emissions.
In EGR systems, to reduce NOx emissions, exhaust gas is
recirculated back into the combustion chamber and mixed with
fresh air at intake stroke. Consequently, the efficiency of
combustion is worsened leading to the decrease of combustion
temperature which means a reducing in NOx formations. EGR
has a widely used range in diesel vehicles. Also, because of the
reduction of temperature in cylinder, this technology generates
an increase of HC and CO emissions.
Owing to the rapid increase of motor vehicles and very
limited use of emission control technologies, transport emerges
as the largest source of urban air pollution, which is an
important public health problem in most cities of the
developing world. Air pollution in developing countries
accounts for tens of thousands of excess deaths and billions of
dollars in medical costs and loses productivity every year.For
the complete destruction of polluting emissions from diesel
engines, further studies and researches on the after treatment
emission control systems should be intensified and continued.
DEVELOPMENT OF CAR IN AZERBAIJAN
Student: Supervisor:
Gafarov Elmar teach. S.T. Imanova
I year, group 405.7
I will speak about the emergence history of car in
Azerbaijan, its development and as a result in Azerbaijan
emergence car factories.
Our car history coincide early in the 20th. In 1911 in
Azerbaijan there were 36 cars. And in 1920 and 1930
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