- •Variant – 1
- •Variant – 2
- •Variant – 3
- •Variant – 4
- •Variant – 5
- •Variant – 6
- •Variant – 7
- •Normalization of the harmful substances, disposal with sewage.
- •Variant – 8
- •Variant – 9
- •Normalization of the harmful substances, disposal with sewage.
- •Variant – 10
- •Variant – 11
- •Variant – 12
- •Variant – 13
- •Variant – 14
- •Variant –15
- •Variant – 16
- •Variant – 17
- •Variant – 18
- •Variant – 19
- •Normalization of the harmful substances, disposal with sewage.
- •Variant – 20
- •Variant – 21
- •Global Warming
- •Variant – 22
- •Variant – 23
- •Variant – 24
- •Normalization of the harmful substances, disposal with sewage.
- •Variant – 25
- •Variant – 26
- •Variant – 27
- •Variant – 28
- •Variant – 29
- •Variant –30
Variant – 22
Absolute and specific growth rate.
Absolute (general) growth rate is expressed by the relation:
dN/dt,
where dN is a change of the community number for a time interval dt.
Specific growth rate is a relation of growth rate to initial number (N):
dN/(Ndt).
In the absence of limiting factors of environment specific growth rate is equal to size r which characterizing properties of the community and it is called specific (congenital) growth rate of the community or biotic potential of a kind:
r == dN/(Ndt) или dN/dt = rN.
The value of biotic potential is differed for different species. For example, roe is capable to make for a life of 10-15 kids, female of melliferous bee - 50 thousand eggs, a fish-moon - to 3 billion of calves.
However in the nature, due to action of limiting factors, the biotic potential of community is never realized completely. Usually its size is defined as a difference between birth rate and death rate in the population:
R = b - d.
Where b is a number of born species, d is a number of lost species in the community for the same period of time.
When b = d, r = 0 and the community is in stationary conditions. When b> d, r> 0, number of the community increases. When b <d, r <0, number of the community is decreased. The formula d = b - r makes it possible to define death rate which it is difficult to measure directly, and it is possible to simply define r by direct supervision.
Growth rate can be expressed in the form of a curve of population growth. There are two basic models of the community growth: J-shaped and S-shaped.
The J-shaped curve reflects unlimited exponential growth of the community number, not depending on density of the community. Such type of growth is possible while biotic potential of the community (r) is realized completely. It proceeds while the competition for resources is low. However after excess of environment capacity (limiting density of saturation, limiting number) (K) there will be a sharp decrease in number.
S-shaped (logistical) curve reflects logistical type of the growth depending on density of the community at which growth rate of the community decreases in process of number growth (density). If the number of community reaches the maximum the growth rate decreases to zero.
Dry Dust removal equipment
The dust removal equipment available may be divided into two large groups: Dry dust removal equipment and wet dust removal equipment. For both groups: A few representative examples will be discussed.
In dry dust removal equipment dust separation from the carrier gas is achieved directly i.e. in the dry state, without the use of a special dust collection agent like water drops. The collected dry dust can be directly disposed of. The use of dry dust removal equipment involves however the danger of dust explosion. Therefore, special measures have to be taken to prevent dust explosion and pressure release in case of explosion.
The separation of dust particles from a gas is mainly due too the action of three forces: inertia force, surface or adhesion force, and electrical force. In most of the dry dust separators, one force dominate over the other thus determines the separation process. According to the prevailing force there are three groups of the dry dust removal equipment:
1. Mass force separator.
2. Adhesion force separator.
3. Electrical force separator.
A typical mass force separator is the cyclone. Under the action centrifugal forces, the dust particles are separated from the gas phase. Conventional adhesion force separators are bag and pocket filters. A typical electrical force separator is the plate precipitator. The three types of dry dust separators are schematically illustrated in Fig. 1.
The elementary evolutionary phenomenon
Genetic structure is a relationship of various genotypes and equilocal genes in the community. Totality of genes of all community species is called genofund. The genofund is characterized with frequencies of equilocal genes and genotypes. Frequency of equilocal genes is its share in all totality of equilocal genes of the given gene. The sum of frequencies of all equilocal genes is equal to unit.
The long and directed change of genetic structure of community, its genofund is called the elementary evolutionary phenomenon. Without change of the community genofund, evolutionary process is impossible.
The factors changing genetic structure of community are following:
1) Mutation is a source of new equilocal genes appearance;
2) Unequal capable of living of species (species are subjected to action of selection);
3) Not casual interbreeding;
4) Drift of genes is a change of equilocal genes frequency, which are casual and independent of selection action (for example, flashes of diseases);
5) Migrations are outflow of available genes and (or) inflow new ones