Experimental Study of Hysteresis in Clayey Soils under Compression

The energy dissipation for one cycle of clay soil deformation over the area of ​​a hysteresis loop under conditions of one-dimensional deformation has been experimentally studied. Several series of trials were carried out under different conditions of soil density and moisture and different loading modes. It was established by the experiments that after several cycles of loading and unloading of the samples, the transient process of the closed loop formation ends and certain dependences of stress on deformations are established in the sections of the ascending and descending branches of the hysteresis loop. To determine these dependencies, rheological relations obtained directly from the hysteresis loop by approximating the arcs of its contour have been used. By integrating the approximating rheological dependences along the branches of the loop, the dissipated energy per deformation cycle has been obtained as a function of cyclic deformation amplitude, measured by the area of the hysteresis loop. Experiments on obtaining a hysteresis loop were carried out on a compression device with a cyclic sample. Samples with different states of density and moisture content were produced by consolidating a paste having yield point moisture under different pressures. Several series of experiments have been carried out. In the first series, soil absorption coefficients were derived for different states of density-moisture at different loading rates. In the second series, three types of clayish soil (clay, loam, sandy loam) were studied. Dissipation coefficients have been found out for the indicated soils. In the third series, three types of clay soil were tested under different conditions of density and moisture. The dissipation coefficients have been obtained. In the fourth series, the dependences of the absorption coefficient on the amplitude value of the cyclic stress for three types of clay soil were disclosed. It was found that a change in the loading rate within the range from 0.05 MPa to 0.2 MPa does not lead to the significant change in the absorption coefficient, the increase in the number of clay fractions in the sample leads to an increase in the absorption coefficient, a change in the amplitude of cyclic loading (in the indicated range of change) does not affect the absorption coefficient.

Reproductive features of the biology of some ticks of the family Ixodidae Murray, 1877 widespread in the southeast of the North Caucasus

The purpose of the research is study of some reproductive characteristics of the biology of ticks of the family Ixodidae which are widespread in the southeast of the North Caucasus.Materials and methods. In 2000–2010, 9 series of experiments were carried out in the conditions of the plain belt in Dagestan. The first, second, and third series of experiments were intended to find out the duration of the tick searching for a place to fix on the animal, the duration of the skin incised and the proboscis inserted into the wound, and the engorgement duration; and the fourth series was intended to clarify the tick wintering on the animal. Such experiments were performed on two-year-old calf bulls on the Educational and Experimental Farm of the Dagestan State Agrarian University with Boophilus annulatus, Rhipicephalus bursa, Hyalomma detritum, H. scupense, and H. anatolicum in 2000. Five hungry adult female ticks were placed onto all 5 calf bulls in the middle third of the neck. We conducted experiments on searching for a place for egg-laying, egg-laying duration in the environment, number of eggs in a clutch, duration of the larva formed and the hatching rate, distance of the larvae from the hatching place, and larvae death rate in five specially equipped sites of pastures of 1 m2 . Five adult female ticks of B. annulatus, R. bursa, H. detritum, H. scupense, and H. anatolicum were placed after engorgement in each biological site.Results and discussion. Ixodid ticks perform their natural physiological functions associated with feeding and reproduction with significant time fluctuations. The search for a place to fix on the animal took 4–8 hours; the skin incised and proboscis inserted in the wound took 2–5 hours; the engorgement took 4–6 hours; the search for an egg-laying place took 10– 22 hours; the egg-laying duration in the environment was 18–23 hours; the number of eggs in a clutch was 4–13K; the duration of the larva formed and the hatching rate was 10–15 days and 58.0–75% respectively; the distance of the larva from the hatching place was 0.5–1.5 m; death rate of the larva in captivity was 100%; and the tick wintering on the animal was near the neck, ears, in the dewlap, the flank and the udder. These features are typical for the analyzed tick species in the southeast of the North Caucasus and, probably, for other taxa of these genera.

Didactics: Peculiarities of Motor Skills Development in Boys Aged 14-15

The purpose of the study was to determine the peculiarities of motor skills development in boys aged 14-15. Materials and methods. The study participants were boys aged 14 (n=20) and 15 (n=20). The children and their parents were fully informed about all the features of the study and gave their consent to participate in the experiment. To solve the tasks set, the following research methods were used: study and analysis of scientific and methodological literature; pedagogical observation, timing of training tasks; pedagogical experiment, methods of mathematical statistics, discriminant analysis, nearest neighbor analysis. Results. The study made an assumption about a significant influence of the modes of alternating exercise repetitions and the rest interval on the effectiveness of motor skills development in boys aged 14 and 15. The standardized canonical discriminant function coefficients helped to determine age peculiarities and the peculiarities of influence of exercise modes on the effectiveness of motor skills development. They showed that the components of motor fitness are a priority in developing motor skills. The structure canonical discriminant function coefficients indicate the importance of movement control skills for mastering the entire exercise. Conclusions. Discriminant analysis revealed the peculiarities of motor skills development in boys aged 14 and 15, depending on age and exercise modes. With the first exercise mode, boys aged 15 master the first, second, and fourth series of training tasks more quickly. Boys aged 14 – the sixth series (exercise mode: 6 repetitions, rest interval of 60 s). With the second exercise mode, boys aged 14 master the first and fourth series of training tasks more quickly. Boys aged 15 – the second series (exercise mode: 12 repetitions, rest interval of 60 s). The coordinates of centroids for four groups indicate a significant difference in the influence of exercise repetition modes on the number of repetitions required for motor skills development in boys aged 14-15 during physical education classes. The results of group classification show that 87.5% of the original grouped cases were classified correctly.

Pattern Recognition: Effectiveness of Teaching Girls Aged 15 Acrobatic Exercises

The purpose of the study was to determine the impact of exercise modes on the effectiveness of teaching girls aged 15 a cartwheel. Materials and methods. The study participants were 20 girls aged 15. The children and their parents were fully informed about all the features of the study and gave their consent to participate in the experiment. To solve the tasks set, the following research methods were used: study and analysis of scientific and methodological literature; pedagogical observation, timing of training tasks; pedagogical experiment, methods of mathematical statistics, discriminant analysis. Results. The analysis of averages shows that statistically significant differences in the number of repetitions are observed in performing series of training tasks 1, 2, and 4 (p < 0.05). The girls aged 15 who use the first mode (6 sets 1 time each with a rest interval of 60 s) need fewer repetitions to master the movements of the first (exercises to develop motor abilities) and the second (exercises to master starting and ending positions) series of tasks. The girls who use the second mode (6 sets 2 times each with a rest interval of 60 s) need fewer repetitions to master the movements of the fourth series of tasks (ability to assess movements in space, by time and muscular effort) (p < 0.05). Conclusions. Discriminant analysis made it possible to determine the impact of the number of repetitions on the effectiveness of developing the cartwheel skill in girls aged 15. During motor skills development, both the first and the second variants of exercise modes and rest intervals can be used. For series of tasks 1 and 2, it is advisable to use 6 sets 1 time each with a rest interval of 60 s; for series of tasks 3, 5, and 6 – 6 sets 1 time each with a rest interval of 60 s or 6 sets 2 times each with a rest interval of 60 s; for series 4 – 6 sets 2 times each with a rest interval of 60 s.

COINS OF PANTICAPAEUM AND PHANAGORIA OF THE 3rd QUARTER OF THE 1st CENTURY BCE AS A SOURCE OF HISTORICAL INFORMATION

Статья посвящена оболам, тетрахалам и дихалкам чекана Пантикапея и Фанагории с бюстами Аполлона в лавровом венке, бородатого Геракла, а также Ники с шестиконечной звездой с длинными лучами на аверсе и с изображениями стрелы, лиры и пальмовой ветви, пасущегося пегаса, лука с горитом или со стрелой, лавровой ветви, перевитой лентой, палицы и львиной шкуры, а также проры корабля на реверсе. Их общепринятая классификация до сих пор не разработана, а потенциал как источника исторической информации не раскрыт. Решаем эту задачу, основываясь на результатах иконографического анализа. Выделяем в первую серию оболы со стрелой, лирой и пальмовой ветвью и тетрахалки с пасущимся пегасом на реверсе, выбитые на монетах Асандра. Судя по митридатидской символике, их отчеканили при Скрибонии. После его свержения в Пантикапее были выпущены тетрахалки с горитом и луком и дихалки с палицей и львиной шкурой на реверсе. Относим эти монеты ко второй серии Пантикапея. В Фанагории в период восстания чеканили тетрахалки с пальмовой ветвью. Выделяем их во вторую серию Фанагории. А после победы инсургентов выпустили тетрахалки с луком и стрелой на реверсе. Относим их к третьей серии Фанагории. Судя по разнообразию символики монет, после гибели Скрибония Боспорское государство распалось. В начале правления Полемона I в Пантикапее и в Фанагории были отчеканены однотипные тетрахалки с бюстом Аполлона на аверсе и с пророй корабля на реверсе, что свидетельствует о восстановлении единства государства. Относим эти монеты к третьей серии Пантикапея и четвертой серии Фанагории. Как видим, привлекшие наше внимание монеты как нельзя лучше проиллюстрировали события, произошедшие на Боспоре в последней трети I в. до н.э. The article focuses on the obols, tetrachalkoi and dichalkoi of the Panticapaeum and Phanagoria mints with busts of Apollo in a laurel wreath, bearded Hercules as well as Nike with six-pointed star with long rays on the obverse and with images of an arrow, lyre and palm branch, grazing Pegasus, bow with gorytos or laurel branch, intertwined with ribbon, club and lion’s skin, as well as ship’s prora on the reverse. Their generally accepted classification has not yet been developed, and their potential as a source of historical information has not been revealed. We solve this problem based on the results of iconographic analysis. In the first series, we single out obols with an arrow, lyre and palm branch and tetrachalkoi with a grazing Pegasus on the reverse, embossed on Asander’s coins. Judging by the Mithridatidic symbolism, they were minted in the time of Scribonius. After his overthrow in Panticapaeum, tetrachalkoi with gorytos and a bow and dichalkoi with club and lion’s skin on the reverse were issued. We attribute these coins to the second series of Panticapaeum. In Phanagoria during the period of the uprising, tetrachalkoi with a palm branch were minted. We select them in the second series of Phanagoria. And after the victory of the insurgents, they fired tetrachalkoi with a bow and arrow on the reverse. We attribute them to the third series of Phanagoria. Judging by the variety of coin symbols, after the death of Scribonius, the Bosporus state collapsed. At the beginning of the reign of Polemon I, in Panticapaeum and in Phanagoria, the same type of tetrachalke with a bust of Apollo on the obverse and with ship’s prora on the reverse were minted, which testifies to the restoration of the unity of the state. We attribute these coins to the third series of Panticapaeum and the fourth series of Phanagoria. As we can see, the coins that attracted our attention perfectly illustrated the events that took place in the Bosporus in the last third of the 1st century BCE.