Maximum Permissible Load Research Articles

Strength and deformation analysis of a welded truss under load in fire and emergency temperature conditions

Welded trusses are widely used in civil engineering due to the optimal combination of high manufacturability and the ability to operate in various force scenarios. During operation, such structures are exposed to a complex impact of various technological and accident factors. This makes it difficult to determine the key parameters necessary for the smooth operation of the farms during the planned period of operation. Under the simultaneous influence of force and high temperature factors on the truss structure, damage may occur in structural elements and their joints due to changes in the mechanical properties of the material, which can lead to structural failure. To identify the features of deformation and fracture of the welded truss, full-scale experimental studies were performed for the physical model at temperatures of 20°C, 200°C, and 450°C. A computer modeling experiment was also performed for similar parameters of the impact on the truss. Based on the results of the full-scale and computer modeling experiments, we generated deformation graphs that make it possible to study the strength and deformability of the loaded welded truss at fire and emergency temperatures. A series of graphical dependencies characterizing the strength and deformability of the truss when it is loaded at different temperatures has been constructed. An analytical dependence has been developed that makes it possible to determine the value of the maximum permissible load on the truss at temperatures up to 450°C based on the known value of this load for room temperature conditions with a coincidence of 97.5...98.3%. It is advisable to use the obtained dependence (graphical or analytical) when designing or operating trusses to determine the maximum permissible loads on the structure at elevated temperatures.

Reorganization of industrial zones into a comfortable urban environment

One of the main directions of scientific research on assessing the efficiency of the use of natural territories is a subject related to the development of scientific methods and approaches that provide not only the determination of the number of visitors, but also the active development of nature tourism. The development and education of nature tourism is one of the causes of recreational digression of natural-anthropogenic territorial complexes (hereinafter - PATC). Classifying the negative factors that cause the influence of anthropogenic impact on natural complexes and their consequences, we can distinguish three main types: mechanical, physical-chemical, biological. In the paper, special attention is paid to the condition of management and organization of recreational activities provided for at the PATK in Pushkino, which includes mandatory regulation and control of the number of visitors on the basis of the proposed regulations for the use of the relevant functional zones. On the territory of the Russian Federation in the normative documents established the need to determine the maximum permissible recreational loads (hereinafter - MPRN).

Еколого-економічне забезпечення рекреаційного лісокористування в умовах децентралізації: передумови, цілі та вимоги воєнного часу

It is defined that the factor of the presence of a large number of injured citizens of Ukraine as a result of Russian aggression requires the introduction of additional capacities in the recreational industry to ensure their recovery, in particular by means of psychological rehabilitation. It is revealed that, based on the existing natural and recreational potential of forest biogeocenoses, forestry of Ukraine has significant reserves for the development of recreational infrastructure. It is substantiated that due to the significant impact of recreational activities in forest biogeocenoses on the ecological sustainability of forest ecosystems, it is expedient to develop a system of ecological and economic provision for recreational forest management, taking into account the requirements of wartime and the consequences of deepening decentralization of power and local self-government reform. It is determined that a modern system of ecological and economic provision for recreational forest use should be based on taking into account information and digital, environmental-resource and institutional factors caused by corporatization of the forest sector of the national economy; digital transformation of the system of control over the economic development of forest resources potential; implementation of the basic provisions of international environmental conventions in the domestic practice of forestry. It is proved that an effective system of ecological and economic provision for recreational forest use in wartime conditions can be formed as a result of achieving the main, auxiliary and interim goals of forming a set of recreational and tourism products based on the development of the recreational value of forest biogeocenoses. It is found that in the spectrum of the main goals of ecological and economic provision for recreational forest management, the normalization of the tourist flow is of great importance, taking into account the maximum permissible recreational load on forest biogeocenoses to prevent manifestations of recreational digression. It is substantiated that the development of the infrastructure of recreational forest management and the expansion of the range of recreational services by permanent forest users will make it possible to ensure more efficient commercialization of protected objects that are in the use of forestry entities, thus allowing to increase the level of capitalization of forestry in different natural climatic zones.

Factors associated with bacterial contamination of shallow well water sources. Case Study of Juja hostels Kiambu County

The use of water from polluted water sources poses numerous public health challenges in developing countries. The ultimate purpose of any solid and liquid waste management plan is to mitigate environmental pollution; these goals become unachievable in the absence of a participatory approach to integrated waste management. This study sought to determine the extent of underground pollution of groundwater sources in Juja Town. Sanitary inspection and water quality analysis are complementary and valuable tools for characterizing and protecting water safety. The quality of the shallow wells is of great importance because it is used for consumption in Juja hostels. A two-stage cluster sampling strategy was adopted to obtain a representative sample size. Data collection involved the administration of questionnaires and field observation checklists, and E. coli levels present in the water were determined by the number of positive tubes in the table of computation of most probable number (MPN). Results showed that the predominant types of waste disposal practices observed in Juja were septic tank systems (77%) for liquid waste and private collection (87.3%) for solid waste methods. Sixty-eight per cent of the water samples were found to be positive (they exceeded the WHO (2004) maximum permissible load of 0.01/100 ml for drinking water. Three sanitary risk factors had a statistically significant effect on the dependent variable: the distance of the septic tank from the well on the level of water contamination (0.016), the liquid waste management plan (0.039), and the fitness of the water well cover on the level of water contamination (0.024). Shallow well water sources are unsuitable for use in food processing and drinking due to the presence of E. coli bacteria. The consequences of consuming contaminated water can be expensive to treat. Water from wells in Juja is contaminated with E. coli levels ranging from <3 - >1000 MPN/g, indicating fecal contamination in the area's underground water sources.

Метод определения предельно допустимой нагрузки на экосистему

The study aims to solve the problem of information support for the efficient managerial decision-making system oriented to the development and maintenance of anthropogenic landscapes ecosystems. The primary research task is to formulate a benchmark adequate in terms of environmental quality assessment and management. The research method. The study proposes the estimation method of the maximum permissible load on the ecosystem based on the synthesis of environmental quality evaluation approaches, patterns of ecosystem functioning, and data on hydrocarbon fuel consumption in the territory. Determining the parameters of the studied object’s idealized model allows discovering the limit characteristics of its actual prototype, i.e., the human-transformed ecosystem. The analysis of the investigated landscape’s model optimal parameters makes it possible to establish the maximum values of assimilation potential and safe emission mass for the features of the territory. One of the elements of the proposed method is the calculation of supply air volume for the ecosystem based on the analysis of the gas exchanges process, taking into account the mechanisms of biogeochemical cycles and data on the carbon dioxide emission in the territory. The results of research. The representative subject for determining the indicators of anthropogenic landscapes sustainability to technogenic influences is the city of Nazran, the Ingush Republic. The available information on the dendrometric parameters of chosen monoculture (Fraxinus Excelsior) allowed determining the patterns in the dynamics of bio-productivity characteristics in correlation with the age of growing stock, considering its exposure to environmental impacts, which made it possible to evaluate the ecosystems’ assimilation potential. The study represents the results of the carbon dioxide emissions inventory for Nazran and the estimation of its masses absorbed by the monoculture during photosynthesis. It also theoretically determines the supply air mass and volume values needed for the toxicants’ atmosphere mass limits assessment. The obtained data laid out the basis for calculating the parameters of the territorial environmental sustainability, along with the relative aggressiveness indices for each of the studied pollutants. Conclusions. The proposed approach makes it possible to take into account the specifics of the ecosystem of the particular territory and the uncertainty of the motor transport emissions dispersion, eliminate the inconsistencies of elements of the management system, increase transparency and simplify the decision-making process, and reduce the restrictions of information support system, the ambiguity of managerial decisions’ consequences and the risks of opportunistic behavior, predict the situation in the territory considering various strategies for ensuring the environmental stability, and improve the system manageability as a whole.

The environmental assessment of the specially protected natural area «Lake Dus-Khol» due to its recreational use

This paper deals with the field integrated geo-environmental research of lake Dus-Khol in the summer of 2021. Under the leadership of the Tuvan Scientific Center in the context of project to identify maximum permissible and optimal recreation load on the specially protected natural area the study collected and updated data on the number of visitors and the condition of the coastal ecosystem health. Lake Dus-Khol is located in Tandinsky kozhuun of the Republic of Tuva, 3 km away from lake Hadyn. Dus-Khol is one of the most visited lakes in the Republic of Tuva. The main attractions are therapeutic mud, high-quality rapa, heliotherms, and drinking mineral waters. A regime of regional specially protected natural area has been introduced on the territory of the lake, the main goal is to preserve natural wetland complexes in their natural state and protect them from the negative effects of anthropogenic and man-made factors. Based on the data obtained, the types of recreation, the values of recreational load and the degree of recreational digression of the ecosystem are determined. The forms of recreation, recreation load values and recreation degree of ecosystem were identified based on the received data. The ways of optimizing recreational nature management on the lake were proposed. The visitors were counted by route counting method during the peak season. Data on the types and scale of recreational activities, as well as the degree of recreational digression of natural complexes of the coast were carried out by visual assessments and surveys.

STUDY OF ICE FORMATION PROCESSES ON OVERHEAD POWER LINES AND DEVELOPMENT OF SYSTEMS TO COMBAT THIS PHENOMENON

Icing on the wires of overhead power lines is a big problem to maintain their integrity. The process of icing wires leads to a significant increase in their mass and, accordingly, to large overloads on the wire and electric supports. Exceeding the loads above the permissible ones can cause great damage to power lines. Wires, cables can break, fittings can be damaged and even lead to collapse of electrical poles. At the same time, damage is caused from the undersupply of electricity. This damage may exceed the damage from damage to the elements of power lines. Ice on the wires usually appear in winter, especially when the warming is going to be replaced by a cold snap and the temperature fluctuates around zero. The problem can be exacerbated by strong wind loads. An increase in air humidity also accelerates the formation of an ice "coat" on wires and electrical poles. Under the most unfavorable conditions, the wall thickness of the “fur coat” of ice on the wire can reach more than 70 mm. Such an ice coat can lead to exceeding the maximum permissible loads and damage to the power line, as well as damage from a power outage. The mechanism of ice formation on overhead power lines, as well as negative damage to power lines and high-voltage pylons under the action of ice load, has been studied. An analysis of the known methods of dealing with ice on power lines has been carried out. An innovative device for combating icing formations is proposed. The advantage of the proposed device is the ability to operate in two modes: vibrating and shock-shaking, which expands its functionality. In preventive mode, the device operates continuously due to the interaction with alternating current flowing through the wires of power lines in the normal mode of their operation, without the need for shutdown for maintenance, which gives the electromechanical interactions of devices with the wire of the power line a vibrational character and ensures the continuity of the process of removing water drops from the wires at an early stage before ice formation. Thus, in the preventive mode of operation of the power line, the causes of icing of the wires are eliminated, and not its consequences, which eliminates the need to shut down for maintenance, and reduces the required costs of resources and energy.

Technological Features of Construction and Reconstruction of Geotechnical Structures in the Arctic Zone

Production engineering methods and geotechnical instrumentation for the construction and reconstruction of railway beds in high temperatures in the Arctic zone are proposed. High-technology construction facilitates the development of transport infrastructure of the energy-producing industries in the Arctic. The example of the Northern Latitudinal Railway (NLR) highlights the probability of dangerous cryogenic processes and phenomena during works, such as waterlogging and the structural decline of the active soil layer, the development of taliks, and frost cracking, which lead to a decrease in bearing capacity of soil. The features of the construction and production plans used at the sites of railway embankment reconstruction with heavy-duty equipment are outlined. New process control methods have been developed based on the selection of and systematic changes in the parameters of maximum permissible construction loads depending on the results of geotechnical structure monitoring. The structural diagram of high technology for strengthening the weak subgrade soil under the conditions of talik development is substantiated. In order to regulate intensive process parameters, the vehicle fleet needs to be equipped with positioning devices and automation process control systems. The effectiveness of process control in terms of improving the reliability and accelerating roadbed consolidation is substantiated.

Technological regulation and monitoring of roadbed construction

Background: Long-term deformations of hydraulic structures on weak foundations and swamps lead to the need to develop new construction technologies that increase the bearing capacity of soils. The existing standards for the design of railways and highways are mainly focused on ensuring the safety of the roadbed at the operational stage. Meanwhile, the risks of loss of stability and stability of road sections also arise at the construction stage, especially when powerful heavy construction machinery and equipment are operating.
 Aim: Formation of a technical and technological system functioning on the principles of direct and feedback between the characteristics of the constructed roadbed and the parameters of construction equipment to ensure the safety and quality of work.
 Methods: Technological regulation of loads and impacts of construction machinery and equipment during the strengthening of the foundation and the construction of embankments of the roadbed.
 Results: The composition of the complex technology and the regime of regulation of construction loads have been developed to increase the bearing capacity of weak soils at the base of the roadbed of railways and highways. The features of geotechnical monitoring for the directed improvement of the strength characteristics of soils during the construction period are determined. The expediency of technological regulation of loads and impacts of construction machinery, equipment during the construction of the roadbed is shown.
 Conclusion: The complex technology of increasing the load-bearing capacity of the weak foundation of the roadbed consists in the consistent application of regulated modes of intensive impact on each layer of the foundation with the maximum permissible load during geotechnical monitoring.

Carrying Load and Related Health Disorders and Disability

Introduction:If carrying loads is not done correctly, it may cause many disorders and diseases, such as musculoskeletal disorders, which are considered the first cause of disability. The aim of the study is a comparison between two methods of calculating load limits and determining the health effects and disorders of carrying loads.Methods:Two methods were used to examine and calculate the maximum permissible load weight. The first method was introduced by the National Institute for Occupational Safety and Health (NIOSH), and the second was introduced by the Washington Industrial Safety and Health Act (WISHA). The researcher used both methods to determine the maximum load weight and to compare the responses. Health effects were listed in the checklist. The study was descriptive, evaluated, and analyzed by Statistical Package for the Social Sciences (SPSS) software.Findings:In the first method, recommended weight lifted (RWL) and lifting index were calculated, and in the second method, the maximum allowable load was calculated. The weight obtained by the first method was smaller than the weight obtained by the second method. Carrying heavy loads resulted in low back pain, discopathy, herniation, high ocular pressure, and osteoarthritis.Conclusion:The first method is suitable for determining the permissible load limits. In this way, the pressure on the spine is less likely to occur. In general, health disorders and related disabilities were less likely to happen in this situation.

Study of Anthropomentric and Morphometric Parameters in the Training of Athletes

The purpose of the work was to study the patterns of development and formation of the structure of the skeletal, muscular, circulatory system under the influence of various physical activities in the dynamics, followed by the definition of correlations of the value of anthropometric and morphometric parameters in the training of athletes. Studying of the literature data, we can conclude that modern professional sports requires loads close to maximum, and sometimes even exceeding them, the establishment of these maximum permissible loads and the study of the patterns of their development is a very urgent task. The main problem in training athletes is adequate selection and sports affiliation. Solving the problems of selection involves the creation of a model of the athlete of this specialization, that is a certain set of characteristics that determine athletic performance. This requires anthropometric assessment, morphometric and biometric data to track physical and physiological parameters, information to assess performance and recovery in sports, modification of training regimes to prevent injuries, provide guidance on regulating the use of technologies used in professional sports, as well as to research and make recommendations for the proper collection, storage and exchange of health information. One of important problems of modern morphology is the study of changes that occur in the body under the influence of various factors. This problem has become especially important in connection with the development of sports. High sports performance, associated with a significant load on the athlete's body, encourages scientists, doctors, coaches to search for physiological reserves of the body and search for optimal training regimes. From this point of view, the study of changes that occur in individual organs, systems and in the body as a whole, under the influence of physical activity of varying intensity and nature is relevant and of great practical importance. Conclusion. Modern professional sports require loads that are close to the maximum, and sometimes are such or exceed them. It is the establishment of these maximum allowable loads and study the patterns of their development which is a very promising area. This will allow timely selection of athletes for a particular sport, to carry out preventive and curative measures to improve their structural and functional condition

Экспериментальное исследование механических свойств ахиллова сухожилия кроликов в процессе его восстановления после травмы

Актуальность. Проблема лечения больных с повреждениями сухожилий остается нерешенной. Неудовлетворительные результаты после хирургического лечения, по данным разных авторов, составляют от 15 до 62 %. Функциональный результат после хирургического восстановления поврежденных сухожилий трудно прогнозировать из-за высокого риска образования рубцового блока, препятствующего их свободному скольжению. Спайки нарушают растяжимость сухожилий, что, в свою очередь, сказывается на их прочности. Цель: исследовать в эксперименте прочностные свойства ахилловых сухожилий после их хирургического восстановления с дальнейшим использованием различных медикаментозных препаратов. Материалы и методы. Проведены исследования механических свойств ахилловых сухожилий кроликов, на которых была создана модель их частичного повреждения путем пересечения на 1/2 диаметра. Травмированное сухожилие ушивалось сухожильным швом. В ходе эксперимента изучали 5 групп препаратов ахилловых сухожилий кроликов с пяточной костью по 3 препарата в каждой группе. 1-я группа — контрольная. После выполнения сухожильного шва рану ушивали. Во 2-й группе животным вокруг сухожильного шва вводили препарат нолтрекс. В 3-й группе вводили препарат гиалуроновой кислоты, в 4-й — препарат лидазы. 5-я группа — норма, препараты неоперированных ахилловых сухожилий интактных животных. Все животные были выведены из эксперимента на 60-е сутки. По результатам испытаний рассчитывали величину модуля упругости и предел прочности препарата. Результаты. Наибольшее удлинение под действием растягивающей нагрузки величиной 30 Н было достигнуто на препаратах неоперированных ахилловых сухожилий кроликов — 2,96 ± 0,22 мм. Наименьшая величина удлинения была получена на препаратах контрольной группы — 0,83 ± 0,37 мм. Остальные группы препаратов показали промежуточные значения. Наибольшим значением модуля упругости обладают препараты ахиллова сухожилия кроликов контрольной группы — 0,216 ± 0,123 МПа. Наименьшее значение модуля упругости выявлено при изучении нетравмированных препаратов ахиллова сухожилия — 0,051 ± 0,004 МПа. Наибольшей прочностью обладали препараты контрольной группы (величина предельно допустимой нагрузки 81,81 ± 0,34 Н). Наименьшую прочность продемонстрировали препараты нетравмированных ахилловых сухожилий кроликов (величина предельно допустимой нагрузки 69,72 ± 0,18 Н). Выводы. В процессе восстановления ахиллова сухожилия кроликов после травмы наблюдается увеличение значений показателей, характеризующих прочностные свойства тканей, — модуля упругости, предельно допустимой нагрузки и предела прочности. Величина показателей, характеризующих пластические свойства тканей, уменьшается, что может стать одной из причин развития посттравматических контрактур. Наилучшие показатели с точки зрения пластичности тканей наблюдались в группе препаратов ахиллова сухожилия кроликов, леченных с помощью гиалуроновой кислоты. Наихудшие — в контрольной группе.

Predictive Thin Plate Spline Model for Estimation of Load Carriage at Varying Gradient and Speed

Laboratory-based experimental studies are being carried out for Indian soldiers to estimate optimal load carriage at different gradients and walking speeds. These experiments involve the recording of Cardio-respiratory responses such as Heart Rate (HR), Oxygen Consumption (VO2), Energy Expenditure (EE), Respiratory Frequency (RF), Minute Ventilation (VE), and Maximal Aerobic capacity (%VO2max). Due to limitations in the data sample size that can be obtained in laboratory-based experiments, there is a need for mathematical interpolation to obtain intermediate values in the study. Load carriage can be affected by factors that can be controlled, such as the speed of marching, and also by external factors that cannot be controlled like ambient temperature. Real-time interactions of all the factors also have an impact on the load-carrying capacity. Planning of the mission operations requires the specification of well-defined work-rest schedules and indication of total load limits, to ensure the operational effectiveness of the military personnel. In this paper, we present a Predictive 3-Dimensional Thin Plate Spline Model for efficient estimation of load. We developed a Multiple Linear Regression Model for predicting %VO2max for combinations of load and gradient. The accuracy of the model was 85 per cent and the maximum permissible loads were derived from the prediction model for the physiological limits of 50 per cent, 60 per cent, and 75 per cent of VO2max. A Thin Plate Spline based interpolation technique was used on this Multiple Linear Regression Model to generate optimal load at intermediate values for the experimental study. A similar predictive Interpolation Model was also developed for estimating load for varying walking speeds at level ground.

How to Аssess Еnvironmental Safety?

The analysis of the main approaches to the assessment of environmental safety is presented. The requirements for environmental safety measurement are justified. The relationship between safety and development, safety and danger are revealed. The approach to the environmental safety methodology is proposed. The goals of environmental safety are justified. The article analyzes life expectancy as the indicator of environmental safety and its dependence on other priorities of the state development, such as the cost of childbirth and raising children, support for pregnant and nursing mothers, care for pensioners (the size of pensions, their indexation, retirement age), the cost of ensuring industrial and transport safety, etc. The indicators that determine the quality (state) of the natural environment as maximum permissible environmental loads and the degree of proximity of the ecosystem state to the border of its stability are considered in the article. The possibility and advantages of using the assessment of the photosynthetic organisms (photosynthetics) state as the indicator of environmental safety are substantiated. The possibility of using the other integral biota state indicators to assess environmental safety is shown in the article.

Organizational and economic mechanism for the land use in rural areas

The goal is to consider the problems of institutional and organizational-economic mechanisms for the effective use of lands near the village on the basis of assessment of the existing load of livestock in personal subsidiary plots and the system of its maintenance in various natural and agriultural zones. Objectives – to analyze pasture use in rural settlements and to present the standards for maximum permissible load of grazing of farm animals on the area of pastures in different climatic zones. Results – regions with a shortage of near-aul lands for livestock, high concentration of the rural population, a discrepancy between the livestock number and the level of pasture provi-sion were identified. Areas with a low load of animals on pastures are identified. The ratio of the standards of demand and supply in forage for natural and agricultural zones and animal species is shown. The formula for determining the optimal number of livestock that can be grazed around a settlement, taking into account the feed stock and pasture capacity, is presented. Schemes of pasture rotation are presented and recommendations for their use are developed to preserve the productivity of natural forage areas of zonal types of near-aul pasture lands and to radically improve on the basis of natural economic zoning of the republic. The analysis of the degree of watering of near-village pastures by region is given. Costs per head unit for transition and long-term periods have been calculated. Conclusions – costs for the near future are based on the existing cost structure by item with some amendments. Purchased feed for all types of animals prevails in the cost structure. The degree of maintenance of rangelands in non-State agricultural enterprises within the boundaries of land use, where there is a reserve potential of unused forage lands, has been determined.

APPLICATION OF COUPLED HEC-HMS AND US EPA WASP FOR TRANSPORT MODELLING OF MERCURY IN THE MINING-IMPACTED AMBALANGA RIVER

This study provides a simulation of mercury (Hg) transport in water and sediments in the mining-impacted Ambalanga River located in Upper Agno Subbasin in the Philippines. The Hydrologic Engineering Center - Hydrologic Modeling System (HEC-HMS) and Water Quality Analysis Simulation Program (WASP) of the US Environmental Protection Agency (EPA) were coupled to handle both hydrologic modelling and total Hg transport processes, respectively, for 12 months in the year 2014. Watershed delineation from Digital Elevation Model, rainfall and streamflow data from the local weather bureau, and dam operational data were used to develop the hydrological model. The calibrated HEC-HMS model satisfactorily simulated the flow in the river and its tributaries, which is then used as an input to the Hg transport model. The Ambalanga subbasin was conceptually divided into 29 segments in WASP to represent the water column and the surface benthic sediment. Time-variable sediment and Hg load were applied to the upstream of Ambalanga River. Total Hg concentration in water and sediments at five sampling locations along the Ambalanga River and two sampling locations along the Upper Agno River were measured in 2014-2015, in addition to the Hg monitoring data from the local environmental bureau. The gathered data were used to validate the WASP model, and results show that it was able to reasonably simulate the Hg fate and transport. Simulation results showed a downward trend in Hg concentration in surface water and sediments from upstream to downstream, while Hg in sediments was observed to stabilize over time. The model was further utilized to come up with exceedance curves of Hg in water and sediments as a result of the river’s response to different Hg loading from the known point sources. The exceedance curves derived from the model were used to determine the maximum permissible Hg loading to the river and identify pollution load reduction measures for river rehabilitation.

ВЛИЯНИЕ АЗОТИРОВАНИЯ НА ПРОТИВОЗАДИРНУЮ СТОЙКОСТЬ КОНСТРУКЦИОННЫХ СТАЛЕЙ ПРИ КОНТАКТНОМ ВЗАИМОДЕЙСТВИИ

We investigated pairs of reverse sliding friction and pairs that simulate the operating conditions of gear wheels in linear contact with sliding of roller samples. The intensity of wear (Ih), the coefficient of friction (f), the maximum permissible load (Pd), which determines the bearing capacity of the contact, and the critical pressure (Pcr), at which seizure are formed, were evaluated. It is shown that at a sliding speed of 0.19 m / s for a pair with a nitrided layer Pd = 40 MPa, Pcr ≥ 40 MPa, Ih = 0.8.10-9, f = 0.10; cemented - Pd = 20 MPa, Pcr = 25 MPa, Ih = 1.4.10-9, f = 0.13. Anti-seize resistance for pairs with a nitrided sample is 25-30% higher. An experimental assessment of the bearing capacity of the interface, the critical load at which scuffs are formed, showed a higher efficiency of nitriding in comparison with carburizing. The provisions on the structure of the nitrided layer are formulated, providing an increase in the performance of the friction pair: the formation of a surface layer above the diffusion zone, consisting of the ɛ-phase (Fe2-3N) in the nanocrystalline state. A thermodynamic hypothesis of the effect of nitriding on the seizure resistance of steel friction surfaces is formulated.

Health of the territory’s population: the main factors and trends in reducing their impact

An analysis of the situation in one of the regions of the Russian Federation was carried out on the basis of the official information available. Mortality in the region has been declining for several years until 2020. However, the trend continued in the largest city of the region. Comparison of the estimated pollutant emission masses in Rostov-on-Don with the maximum permissible load on the ecosystem shows their exceedance by the main pollutants by a tenfold, which indicates the importance of the environmental factor for public health. It was noted that under restrictions associated with the outbreak of infectious diseases, the environmental factor for the territory had declined and other factors were likely to increase. Different approaches can offer a range of tools, which implies the need for scientific discussion based on current developments. Refusal to explore alternatives creates moral risks for the informed party. The experience of 2020 allowed accumulating competencies and working out actions for the formation and implementation of a strategy of behaviour in the future. One of the dominant factors contributing to the improvement of public health is the preservation and strengthening of immunity. Common effective means of increasing immunity in urban environments are considered.

Assessment of the Maximum Permissible Load of Pollutant in an opened coastal zone using a water quality model: a case study in Hainan of China

This study aims to estimate the maximum-permissible-loads of pollutant by means of water quality modelling, in order to maintain the concentrations of pollutions below prescribed water quality targets. Modelling of water quality used the Mike21 HD and ecolab modules, while the assessment of maximum-permissible-loads of pollution used the method of response factor coefficient. This research is descriptive quantitative parameters of COD. A scenario assessment was carried out by the flows from various point sources to understand the site-specific relationships between pollution sources and water quality conditions, as well as calculating the maximum-permissible-loads to determine the pollution point source discharge.

ИСПОЛЬЗОВАНИЕ ПАСТБИЩНЫХ УГОДИЙ ПРИ СОДЕРЖАНИИ СКОТА В ЛИЧНЫХ ПОДСОБНЫХ ХОЗЯЙСТВАХ

The authors of the article consider the institutional framework for regulating the use of rangelands in rural areas for the effective maintenance of livestock on household farms. On the basis of a detailed analysis, the issues of pastures allocated for livestock grazing to personal subsidiary farms have been identified. An assessment of the pasture lands of rural settlements and standards of the maximum permissible load of grazing of agricultural animals on the area of pasture turnover for the natural-agricultural zones of the republic and types of livestock are presented. The regions with a shortage of pasture lands and high concentration of the rural population, located in the foothill-desert-steppe, foothill-desert and mountain zones, incompliance of livestock kept in households and the level of pasture provision are identified. Areas with a low load of livestock on pasture land are identified. In the desert and semi-desert zones, there is an insufficient number of livestock for effective near-village pasture rotation. The ratio of the standards of need and provision in pasture fodder in different natural and agricultural zones by species composition of livestock is shown. The degree of use of pasture lands in various forms of economy of the republic is indicated, pastures assigned to peasant (private) farms are used with full load. Non-state agricultural enterprises within the boundaries of land use have a reserve potential of unused pastures with an area of 10.4 mln ha. A formula for determining the productivity and capacity of pasture lands for organizing cattle grazing is presented. Recommendations and schemes of pasture rotation are presented to preserve the productivity of natural forage lands of near-aul territories of zonal types of pastures, to radically improve the natural-economic zoning of Kazakhstan.