The article presents the results of studying the influence of the supplementary feeding with stinging nettle hay on the ration balance, biochemical indicators, nutritional value, and keeping quality of rabbit meat. It was established that the replacement of 5% and 25% of coarse fodder with stinging nettle hay resulted in an increase in the content of crude (by 3.5-20.3%), digestible protein (by 4.4-22.8%) and carotene (by 3.3-22.7%) in terms of nutritional value. Growing rabbits with the introduction of a dosage of 5% and 25% of the stinging nettle hay of the nutritional value of coarse fodders was characterized by the least feeds per 10 g of the gain as compared to the content in the traditional ration (1.17 kg of feed units/day). The introduction of 5% of the nettle hay into the rabbit ration as compared to the control group: influenced a decrease in the moisture content (the power of influence of -10,38%, P<0.001), an increase in the content of protein (the power of influence of 34.2%, P<0.01), zinc (the power of influence of 35.6%, P<0.01) and manganese (the power of influence of 34.2%, P<0.01) in the rabbit meat.

This article analyzes the areas of localization of wear of the outer plating of the hulls of ships of inland and mixed (river-sea) navigation and the causes of them. It is noted that the problem of wear of outer plating sheets is associated with the tasks of ensuring watertightness and strength of ship hulls, on which the preservation of the functionality of ships as floating transport engineering structures depends. The results of the study show that: 1) wear of the outer skin of the vessels of inland and mixed (river-sea) navigation of the studied groups (pusher tugs, oil ore carriers, dry cargo and passenger ships) have different localization; 2) the localization of wear depends on the area of ​​operation, the main dimensions and design features of the ships; 3) wear is caused by corrosive, erosive and abrasive effects of the external environment, structural changes in the metal in welds and near-weld zones, as well as poor quality of paint and varnish protection of ship hulls, insufficient vibration damping of ship mechanisms, in some cases, unsatisfactory alignment of ship mechanisms and shafting; 4) local residual deformations (dents, crooks, ribbing), the frequency of their formation, the appearance and development of cracks in welds and the whole metal are due to the loss of stability of bonds due to their wear; 5) there is a correlation between the wear values and residual deformations of the outer skin sheets. Establishing the type of correlation dependence requires special study.

The most common and reliable method of protecting a ship’s hull from corrosion is paint coatings. Paint coatings can be used to paint products of any size. In case of complete or partial destruction, the paintwork can be easily restored by tinting or completely repainting the surface. Paints and varnishes are easily combined with other methods of corrosion protection. The use of paint coatings is more economical in comparison with other types of corrosion protection. Therefore, it is currently the most common method of protecting ship hulls. In order to determine the quality, the experimental studies of various paints and varnishes were carried out. Experimental prototypes were made. The effect of low temperatures and the effect of an impending water flow on paint and coatings were considered. The main conclusions were drawn from the results of the experiments. For long-term protection from the external environment, it is necessary that the coating film should maintain high adhesion to the surface maintain continuous, have minimal water absorption, devoid of pores and be solid. Samples with a two-layer and three-layer coating of Jotun paint have the best adhesion. Satisfactory results were also obtained on samples with a three-layer coating of XC-436 enamel and with a two-layer coating of stone red.

Волжский государственный университет водного транспорта», г. Нижний Новгород, РоссияАннотация. Целью исследований является оценка особенностей формирования температурных полей при плазменной резке и разработка технологических рекомендаций для назначения режимов резки основных групп сталей для формирования качественных кромок реза. В статье выявлены отличительные особенности формирования температурных полей при разделительной плазменной резке. Перечисляются факторы, влияющие на их формирование. Представлены графики распределения температур по толщине разрезаемого листа, изотермы температурных полей для рассматриваемого диапазона температур. Приведены принципы, исходя из которых авторами выполнены соответствующие расчѐты и получены математические зависимости. Выполнен анализ уравнения теплового баланса процесса разделительной резки, описаны члены этого уравнения, и принципы ведения статистики по значимым для составления уравнения баланса факторам. Описаны общие подходы для определения ширины зоны термического воздействия при плазменной резке и описания происходящих в этой зоне процессов окисления металла, содержащего различные характерные примеси. В заключительной части приведены таблицы структур зоны термического влияния и даны технологические рекомендации по плазменной резке конструкционных и инструментальных сталей с рекомендуемыми режимами их термической обработки и рассмотрением некоторых типичных особенностей, характерных для резки некоторых марок сталей.

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