The history of earthworms? What are the environmental conditions for earthworms? What is the anatomy

The body of an earthworm is made up of many somites with somites, bristles, and dorsal pores.

The body of an earthworm is divided into most segments (as many as 150 segments). Certain internal organs, such as excretory organs, are found in each somite. Section 32 and 37 are slightly thicker, without internode grooves, slightly lighter in color, and can secrete viscous substances during the reproductive season, forming vermicoons, wrapping the discharged eggs.

The anterior and posterior ends of the earthworm's body are tapered, and the tail end is slightly blunt. Earthworms have no visual or auditory organs, but they can sense light and vibrations. Feeds on decaying organisms in the soil, swallowing large amounts of soil, sand and tiny stone chips while eating.

It is estimated that the daily intake and excretion of earthworms are equal to their body weight.

Earthworm. It is a saprophytic animal, living in a humid environment, feeding on putrefactive organic matter, and living in an environment full of microorganisms but rarely getting disease, which is related to the earthworm's unique antibacterial immune system.

Relate. Vermicompost is mainly used for biofertilizer, soil improvement, detoxification, adsorbent, prevention of pests and diseases, etc. Different from general fertilizers, it is odorless, tasteless, granular, and has good water absorption and permeability.

Earthworm: Earthworm, also known as Earth Dragon, is a terrestrial invertebrate of the Oligochaeta class of the phylum Annelids.

Earthworms are one of the annelids, there are more than 3,000 species of earthworms in the world, and there are more than 200 species in China. There are ringworms, Aisheng worms, heterolip worms, dura worms and other varieties widely distributed throughout the country.

Earthworms are rich in nutrition, rapid reproduction, miscellaneous diets, and high yield in artificial breeding. Good economic benefits. Earthworms can be used as a valuable medicine** for many diseases, and can also be used as high-protein food and feed.

Earthworms dig holes to loosen the soil, decompose organic matter, create good conditions for the growth and reproduction of soil microorganisms, and improve soil improvement, eliminate pollution, protect the ecological environment, and in material circulation and biodiversity.

At present, many countries use earthworms to dispose of household waste.

Organic waste and purified sewage.

Earthworms contribute to the material cycle and energy transfer of soil processes through activities such as feeding, digestion, excretion (vermicompost droppings), secretion (mucus) and burrowing, and are one of several soil invertebrate groups (mainly earthworms, mites and ants) that have an important impact on the processes that determine soil fertility, and are known as ecosystems.

Engineer.

Earthworms do not have special respiratory organs, and earthworms' respiration is completed by a body wall that can secrete mucus and always remain moist Therefore, earthworms need to live in moist soil to keep the body wall moist Earthworms belong to ectotherms and cannot maintain a constant body temperature, so they can only live in soil with little change in temperature Therefore, earthworms need to rely on moist body walls to breathe, and their body temperature is not constant, so they are only suitable for living in moist soil

Earthworms are suitable for use in humid environments. They are loosens of the land.

Discharge cooling is another type of convection cooling. Unlike regenerative cooling, the coolant used for exhaust cooling absorbs heat to the thrust chamber and is discharged out of the combustion chamber instead of entering the combustion chamber to participate in combustion. Direct drain coolant reduces the thrust chamber specific impulse, so the coolant flow for drain cooling needs to be minimized while only using drain cooling at the outlet section of the nozzle that is relatively less heated.

There is also radiative cooling, in which the heat flow is transferred from the combustion products to the thrust chamber, and then the heat is radiated by the thrust chamber wall to the surrounding space. Radiative cooling is characterized by simplicity and small structural mass. It is mainly used in the extension section of large nozzles and the thrust chamber of small thrust engines using high-temperature resistant materials.

When cooling in the thrust chamber of the tissue, a relatively low temperature liquid or gas protective layer is established on the surface of the thrust chamber wall to reduce the heat flow to the thrust chamber wall, reduce the wall temperature, and achieve cooling. Internal cooling is mainly divided into three methods: internal cooling (shield cooling), membrane cooling and diaphoretic cooling of head tissues. After the internal cooling measures are adopted in the thrust chamber, the mixing ratio near the wall of the combustion chamber is different from the optimal mixing ratio in the central area (in most cases, the near-wall layer rich in fuel is used) due to the need to reduce the temperature of the protective layer, resulting in the uneven distribution of the mixing ratio along the cross-section of the combustion chamber, so that the combustion efficiency is reduced to a certain extent.

Membrane cooling is similar to shield cooling in that it cools the thrust chamber wall by establishing a uniform and stable coolant film or air film protective layer near the inner wall surface, except that the coolant used to establish the protective layer is not injected by the injector, but is supplied through a special cooling belt. The cooling band is generally arranged in a cross-section of the combustion chamber or the convergence section of the nozzle. There can be several cooling bands along the length of the combustion chamber.

In order to improve the stability of the membrane, the coolant often flows through the gaps or small holes in the cooling belts, and when sweating is used, the thrust chamber wall or part of the inner wall is made of porous material with a pore diameter of tens of microns. Porous materials are usually sintered with metal powders or pressed with metal mesh. In this case, the number of pores per unit area is increased by making the micropores in the material as evenly distributed as possible.

The liquid coolant penetrates into the inner wall, creating a protective film that reduces the density of the heat transferred to the wall. When the flow rate of liquid coolant used for sweat cooling is above a certain threshold, a liquid film is formed near the wall of the thrust chamber. When the coolant flow rate is below the critical flow, the inner wall temperature will be higher than the coolant boiling point at the current pressure, and some or all of the coolant will evaporate, forming an air film.

In addition to the above thermal protection, there are other thermal protection methods such as: ablation cooling, thermal insulation cooling, hot melt cooling and composite protection of chamber walls. 3. Thermal protection scheme of high enthalpy gas generator Based on the above methods and the actual situation, the thermal protection method of high enthalpy gas generator is obtained.

The combustion chamber of a high-enthalpy gas generator differs from that of a liquid rocket engine, eliminating the front thrust chamber part, making its structure simpler and more effective. Then, the thermal protection involved is the thermal protection part of the combustion chamber wall. As the fuel enters the combustion chamber, it quickly decomposes and releases large quantities.

The body of an earthworm is made up of many parts, including a head, abdomen, and tail. The body is segmented but not divided, the verrucous feet are vestigial, and the body surface is bristled. Hermaphroditic, 1-2 pairs of gonads, reproductive ducts of body cavity origin, rings (clitellum) appear on the body surface when sexually mature, mutual insemination can be done during mating, eggs are laid in the rings, and after falling off, egg cocoons are formed, and they develop directly.

The bristles are simple, 8, sometimes many, arranged in a ring, 1-2 pairs of sperm nests, usually at 10-11 nodes, male reproductive pores one pair, located on 2 or more somites after the posterior sperm nest, i.e. after 14 nodes. A pair of ovaries, located in the 13th segment, with a thicker annular band and less yolk.