Note that the grain size of the metal strongly affects its mechanical properties. The finer the grain, the higher the strength of the metal, its hardness, toughness, plasticity, endurance limit (the highest stress that the material can withstand without destruction for a given number of cyclic impacts). Grinding of grain lowers the threshold of cold brittleness.

The grain size is affected by the heating and pouring temperature of the liquid metal, its chemical composition, and especially the presence of impurities.

Spontaneous formation of nuclei based on phase fluctuations can occur only in a high-purity liquid metal at high degrees of supercooling - homogeneous crystallization.

Commercial metals always contain a large number of various impurities (oxides, non-metallic inclusions, etc.), which facilitate the formation of nuclei. This happens when:

The impurity has a higher melting point than the parent metal,

The crystal lattices of the impurity and the base metal are the same and the lattice parameters are approximately the same.

The more impurities, the more crystallization centers, the finer the grain. This formation of embryos is called heterogeneous.

To obtain fine grains, artificial crystallization centers are created. To do this, special impurities are introduced into the liquid metal, called modifiers, and the process itself modification. These impurities, practically without changing the chemical composition of the alloy, cause grain refinement during crystallization and, as a result, an improvement in mechanical properties.

When casting ingots, modification is often carried out by introducing additives into the melt, which form refractory compounds (carbides, nitrides, oxides), which crystallize first. Standing out in the form of the smallest particles, these compounds serve as nuclei (modifiers of the first kind). Used as modifiers in the modification of steel Al, V, Ti.

Sometimes, additives soluble in the liquid metal (modifiers of the second kind) are used, which are selectively adsorbed on the crystalline nucleus, which reduce the interfacial surface tension and hinder the growth of crystallites. For steel, these are rare earth elements (yttrium, lanthanides).

2.4. The structure of a metal ingot

The crystals formed during the solidification of the metal may have a different shape depending on the cooling rate, the nature and amount of impurities. More often, in the process of crystallization, branched (tree-like) crystals are formed, called dendrites.

The growth of the first-order axes proceeds mainly in the direction perpendicular to the planes with the maximum atomic packing density. At the same time, on these axes, the same branches of the second order are born and grow perpendicular to them, and, in turn, on them, axes of the third order. It should be borne in mind that the dendrites in steel consist of many thousands and millions of grains.

The structure of the cast ingot consists of three main zones. Crystallization starts from the surface of a colder mold and occurs at first predominantly in a thin layer of strongly supercooled liquid adjoining the surface. Due to the high cooling rate, this leads to the formation of a very narrow zone of relatively small misoriented crystals on the surface of the ingot. The second zone is elongated (columnar) dendritic crystallites (transcrystallization zone). The growth of these crystallites occurs in the direction of heat removal, i.e. normal to the walls of the mold. The successive growth of dendrites occurs as a result of the first-order branches moving deep into the melt and their branching. In the case of strong overheating of the metal and rapid cooling, zone 2 can completely fill the entire volume of the ingot. The third zone is equiaxed crystallites. In the center of the ingot, there is no longer a certain direction of heat transfer. The temperature of the solidifying metal equalizes at various points, and “the liquid turns into a mushy state, as it were” (D.K. Chernov), due to the formation of nuclei at its various points. The refractory particles in the liquid metal contribute to the development of a zone of fine equiaxed crystallites.

Liquid metal has a larger volume than crystallized, so the metal poured into the mold during crystallization is reduced in volume, which leads to the formation of voids, called shrinkage shells. They can be filled with gases that are soluble in the liquid metal but released during crystallization. In calm steel, cast into a mold with a heat-insulated extension, a shrinkage cavity is formed in the upper part of the ingot. Boiling steel contains shells and bubbles throughout.

Typically, a shrinkage cavity is surrounded by the most contaminated part of the metal, in which micro- and macrobubbles form after solidification.

During the crystallization of alloys segregation can take place. segregation called non-uniformity in the chemical composition of the components and impurities included in the alloy, formed in the process of crystallization. There are the following types of liquations:

- dendritic segregation is a non-uniformity in the chemical composition of components or impurities within one dendrite;

- zonal segregation is a non-uniformity in the chemical composition of components and impurities in the bulk of the ingot. First crystallize crystals relatively clean from impurities, they drive away into the depths of the ingot liquid rich in impurities. Thus, the central part of the ingot has an increased amount of impurities. In iron-carbon alloys, sulfur and phosphorus are strongly eliminated. The accumulation of sulfur compounds in certain areas is extremely harmful, since they lead to a dangerous concentration of stresses when the force is applied to the part, which causes instantaneous fatigue failure. Due to segregation of phosphorus, individual layers of the ingot, enriched with it, have a sharply reduced viscosity;

The Elder Scrolls V: Skyrim - Polygamy ​

Game platform: TES V: Skyrim Legendary Edition​

English title: Multi Marriage​

Russian name: polygamy

Current version: 1.2​

Mod language: Russian

Size: 90 Kb

Description ​

The essence of the modification fully corresponds to its name. Mod allows the player to be in a polygamous marriage. Options for both polygamy and polyandry are possible.​

Update 1.2:​

• The maximum possible number of spouses is fifty;
• Fixed previous stall issues (appears to be related to stalls in Herthfire estates)
• Added Serana with dialogues, optional;
• The next update will allow up to fifty foster children.

Update 1.0:​

• Fixed a critical bug that prevented spouses from returning to their home;
• Introduced player faction (playerfaction);
• Update for Hearthfire multiple adoptions.

Mod content details:​

• In MSM, you need to go to the menu, the "Installation" section and start the modification.
• A new spell "Power of Mara" has been added, when cast, a selection window appears on the character. By selecting "Yes", the player enters into marriage and sees new dialogues.
• In the dialogue menu there is also the possibility of a divorce. No judges for you, no saints for you.
• There is the possibility of marriage using the vanilla scheme, but also repeatedly.
• The modification is designed for fifty happy partners.
• Spouses can live in the player's house or in their own, and at other times - engage in trade.
• Each new partner becomes a merchant by default, and the player can also make deals with him (her). (Husband sells goods to his wife! Where is this world heading?!)
• A new quest has been added, displayed in the journal, all spouses are marked with markers, it is possible to control through the MSM menu.
• In addition to marriages, the new spell is able to resurrect the dead and pacify the brawlers or opponents.
• The modification affects all the characters of the mods, however, NPCs must have the voices declared in the vanilla version for the marriage quest. Terrifying manifestation of male chauvinism! Almost all rogues and female necromancers have matrimonial voices, i.e. male players in a clear win.
• The modification does not pay attention to whether the NPC is legally married, and whether it is a quest one. It is recommended not to "drag" such characters to the crown until they complete the quests.
• Aggression of the guards directed against the bandit wife is possible, as well as an attack by the guards of different possessions, soldiers of the Empire, and the like. Perhaps, but not necessarily.
• In the next updates, the number of marriages can be increased to one hundred.

Requirements:​

• Hearthire

The term "modification" can be encountered when buying various equipment or a car. This implies the presence of some new features or fixes for deficiencies based on the old model. But the concept itself is much broader. Consider what modification is and in what areas of life this term is found.

Modification means the transformation of something into a new form with the appearance of other functions, capabilities or properties. This is a qualitative change in a substance or object.

What is modification: scopes

In engineering

Modification in technology involves the creation of a new technology or changes to a specific model. So the improvement of a certain model and the addition of new functions qualitatively changes the original object, but does not change its essence.

For example, an easy ironing function is added to the washing machine. The new model will be a modification of the previous one, as it now has more features. But still it remains a washing machine.

Such modifications are often found in mechanical engineering, when new, more comfortable and safer models are created on the basis of an outdated model.

In biology

This term is widely used in biology, meaning an artificial external change in the body without the influence of hereditary factors. For example, the evolution of species is essentially a modification, when the organism is forced to gradually adapt to a changing environment. Various mutations caused purposefully or as a result of some kind of influence are also modifications.

In breeding, the term refers to the external change of an organism without interfering with its genotype. Here, the manifestation of the same quality as a result of different conditions is considered a modification, for example, with a difference in temperature, lighting, soil, etc.

In chemistry

This refers to a change in the structure of a chemical. For example, diamond and graphite consist of the same chemical element - carbon, but have a different crystal lattice, that is, a different modification of carbon.

Also, the term can mean the result of some chemical process, for example, the modification of proteins.

Other areas of life

The term can be found in psychology when analyzing the patient's mental status (modification of consciousness).

In the theory of versification there are "rhythmic modifications".

Gamers or just fans of computer games have heard the words "mod" or "mods". This is short for modification, meaning additional features or features to a computer game, often written by amateur programmers or third-party professionals.

You can find other terms in our section.

"Fourier series" - we get Then we have: , where for an even function. Fourier series expansion of even functions. Let's expand the Function into a series, and then return to the old variable. Then we have the following formulas: , where. Thus, a, where or. Let us now extend f(x) to a periodic function in an even way. Then, where Calculate the integral by parts:

"Organ transplantation" - Duration of observation. Pancreas transplant. Orthotopic transplant. Diagnosis of brain death. Spleen transplant. Development of clinical transplantology. Immunological aspects of transplantation. Reliability. Prospects for the development of clinical transplantology. Triplet scheme. Legal and legal bases.

"Medical psychology" - Psychocorrection, psychotherapy, psychological counseling. General definitions: "a new field of knowledge, which is a combination of psychology and medicine." Psychosomatic illness: A study of the personality types of patients that determine the patient's response to illness. The study of changes in individual mental functions in somatic and mental diseases.

"Bariatria" - Gastric banding is performed only laparoscopically. Bandaging allows you to achieve weight loss by 50-60% of excess body weight. Gastric banding gastric bypass biliopancreatic bypass. in seven cases out of ten, the weight returns. the branch of medicine that deals with the treatment of excess body weight.

"Surgery" - Antiseptics - a method of fighting infection English surgeon J. Historical information. The surgeon Warren in 1846 removed a neck tumor under ether anesthesia. Russian surgery. Classification of operations by nature and purpose: Features of modern surgery. In 1901, Karl Landsteiner discovered blood types. Therefore, to combat microbes, they began to spray carbolic acid in the operating room.

"Dentistry" - Percussion. Stages of treatment of a carious cavity. Treatment. Pulpitis. Periodontal examination. Dentistry. Black classification. Methods of treatment of pulpitis. dental formula. clinical picture. Microscopic research methods. Classification of the carious process. Medium caries. Rough machining.

VARIABILITY OF ORGANISMS.

MAIN REGULARITIES OF THE PHENOMENA OF VARIABILITY

Genetics studies not only the phenomenon of heredity, but also the phenomenon of variability.

The variability of organisms is expressed in differences between individuals in a number of characters or properties. These differences may depend on changes in the hereditary factors of the genes they received from their parents and on the external conditions in which the organism develops.

We can say that variability is a property opposite to heredity. Variability has determined the diversity of living nature in the course of evolution.

The assessment of the diversity of traits - variability - in individuals is always made according to their phenotypic manifestation. However, the reasons for their phenotypic diversity may be different: the difference in genotypes or the diversity of environmental conditions that determined the variation in the manifestation of traits in organisms of the same genotypes.

There are 2 forms of variability (Figure 14):

ü hereditary (genotypic);

ü non-hereditary (phenotypic = modification).

Hereditary variability is associated with changes in hereditary factors. There are two types of hereditary variability: combinative and mutational.

Combinative (hybrid) variability is characterized by the appearance of neoplasms as a result of the combination and interaction of genes of parental forms.

Mutational variability causes structural changes in chromosomes, leading to the emergence of new hereditary traits of the organism.

Modification variability does not cause a change in the genotype, it is associated with the reaction of the same genotype to a change in the external conditions in which the development of the organism takes place and which create differences in the forms of its manifestation.

Figure 14. Classification of variability.

modification variability.

Modification variability (= phenotypic variability)- these are changes in the characteristics of organisms that are not due to changes in the genotype and arising under the influence of environmental factors.

Habitat plays an important role in the formation of the characteristics of organisms. Each organism develops and lives in a certain environment, experiencing the action of its factors that can change the morphological and physiological properties of organisms, i.e. their phenotype.

It is assumed that the causes of modifications may be the induction and repression of some enzymes.

An example of the variability of traits under the influence of environmental factors is the different shape of the leaves of the arrowhead: the leaves immersed in water are ribbon-shaped, the leaves floating on the surface of the water are round, and those in the air are arrow-shaped (Figure 15). Under the influence of ultraviolet rays, people (if they are not albinos) develop a tan as a result of the accumulation of melanin in the skin, and in different people the intensity of skin color is different.

Figure 15. Arrowhead common, growing in the water and on the shore.

Modification variability is characterized by the following main properties:

1) is not inherited;

2) has a group character of changes (individuals of the same species, placed in the same conditions, acquire similar characteristics);

3) there is a correspondence of changes to the action of the environmental factor;

4) there is a dependence of the limits of variability on the genotype.

Despite the fact that under the influence of environmental conditions, signs may change, this variability is not unlimited. This is explained by the fact that the genotype defines the specific boundaries within which a trait change can occur. The degree of variation of a trait or the limits of modification variability are called reaction rate.

The reaction rate is expressed in the totality of phenotypes of organisms that are formed on the basis of a certain genotype under the influence of various environmental factors. As a rule, quantitative traits (plant height, yield, leaf size, cow milk yield, chicken egg production) have a wider reaction rate, that is, they can vary widely than qualitative traits (wool color, milk fat content, flower structure, blood type) . Knowledge of the reaction rate is of great importance for the practice of agriculture and medicine.

The modification variability of many traits of plants, animals, and humans follows general patterns. These patterns are revealed on the basis of the analysis of the manifestation of the trait in a group of individuals ( n). The degree of expression of the studied trait among the members of the sample is different. Each specific value of the studied feature is called option and denoted by the letter v . The frequency of occurrence of individual variants is indicated by the letter p . When studying the variability of a trait in a sample population, a variation series is compiled in which individuals are arranged in ascending order of the indicator of the trait under study.

For example, if we take 100 ears of wheat ( n\u003d 100), count the number of spikelets in the ear ( v) and the number of spikelets with a given number of spikelets, then the variation series will look like this.

Option ( v)
Frequency of occurrence ( p)

Figure 16. Variation curve

Based on the variation series, variation curve- graphical display of the frequency of occurrence of each option (Figure 16).

The average value of the trait occurs more often, and variations that differ significantly from it are less common. It is called "normal distribution". The curve on the graph is usually symmetrical.

The average value of the feature is calculated by the formula:

Where M- the average value of the sign; ∑( v· p) - the sum of products of a variant by their frequency of occurrence; n- quantity option.

In this example, the average value of the trait (the number of spikelets in an ear) is 17.13.

Types of modifications:

1. Adaptive modifications - these are non-inherited changes that are beneficial to the organism and contribute to its survival in changed conditions. These are the most famous modifications.

2. morphoses- these are non-heritable changes that occur with the intensive action of certain agents. Most often, morphoses are expressed in the form of deformities - deviations from the standard phenotype.

In evolutionary terms, the significance of modification variability is determined by the norm of the reaction, which gives the organism the opportunity to survive and leave offspring. In the presence of such variability, genocopies of modifications are inherited, that is, mutations whose phenotypic manifestation encodes modification variability. They are picked up by natural selection and, thereby, the adaptability of organisms to new changing conditions increases.

Knowledge of the patterns of modification variability is of great practical importance in agriculture, since it makes it possible to foresee and plan in advance the degree of manifestation of many features of organisms depending on environmental conditions.

No less important is the knowledge of the patterns of modification variability in medicine, whose efforts are aimed not at changing the genotype, but at maintaining and developing the human body within the limits of the reaction norm.