Moisture Content Of Raw Material Research Articles

Improvement of the methods for determining ore losses when designing cement raw material deposit mining by surface miner combines

Relevance. The need to optimize production of cement raw materials and reduce the cost of processing raw materials. A surface miner combine allow high selective mining of a deposit, which helps to reduce moisture content of cement raw materials and reduce energy costs in a cement plant. In open-cast mining of cement raw materials deposits with the use of the surface miner combines, the increase in economic efficiency of mining operations can be achieved by determining the rational values of ore losses and dilution. Aim. To determine rational level of cement raw material losses during field development by surface miners. Objects. Cement industry quarries excavated with of the surface miner combines. Methods. Technical and economic analysis of the cement plant Beočin (Serbia), summation and synthesis of materials, sources and data available in the public domain, as well as calculations to determine the amount of loss and dilution of mineral resources at ore–rock contact for mining conditions of the quarry for extracting cement raw materials. Results. The main problems that arise during mining quarries for extracting cement raw materials have been identified. It concerns the determination of the volume of losses and dilution of mineral resources at the ore–rock contact for mining conditions of the quarry for extraction of cement raw materials. The authors present and substantiate conclusions about further effective application of optimal mining technology, with the use of the surface miner combines, which allows reducing the cost of production of minerals and specific operating costs of transporting carbonate rocks compared to the traditional technology of mining works at 50–60%.

Optimization of Heat Pump Drying Process for Schefflera heptaphylla Leaves by the Response Surface Methodology

Background: Schefflera heptaphylla is a species of plant living in the forest, containing numerous bioactive compounds beneficial for human health. The efficient extraction of these bioactive compounds from the plant while minimizing losses is a currently highlighted issue. Methods: In this research, the impact of three variables: drying time (min), drying air velocity (m/s) and drying air temperature (oC) on the reactions, including loss of total phenolic (TPCL), total flavonoid content loss (TFCL) and moisture content (MC) investigation of Schefflera heptaphylla leaves was conducted using the central complex design (CCD) within the framework of the methodology reaction surface method (RSM). Result: The optimal conditions obtained from the response surface method were 48°C, 1.9 m/s and 600 min. The experimental values at the optimal conditions of TPCL, TFCL and MC are 17.22±0.20%, 14.83±0.15% and 8.47±0.12%, respectively. Crude fiber content, moisture content, total ash and total fat content of raw materials have been identified.

Development of a method and equipment for processing wood biomass into flour

The paper assesses the relevance of processing felling residues at logging sites into semi-finished wood products for further transportation and use at enterprises of the forestry and agro-industrial complex. In particular, the expediency of making wood flour from felling residues is justified. An assessment of the effectiveness of using wood flour as a baking powder for adding to depleted soils and plant insulation is given, which will lead to an increase in the yield of cultivated plants. As a result, the purpose of these studies was to increase the efficiency of using wood biomass by introducing a mobile plant for wood flour production into the logging process. To achieve this goal, the design of a mobile installation for the production of wood flour in logging operations, technology and algorithm of its implementation were developed. To substantiate the effectiveness of design and technological solutions implemented in the process of designing the installation, a multifactorial experiment using a laboratory prototype was planned and implemented. An analysis of the results of experimental studies is presented, regression models and graphical dependences of the size of wood particles on the input parameters of the studies are obtained. The optimal values of the moisture content of the wood raw materials, the wear of the teeth of the working bodies and the gap between them were determined. In the course of the research, methods of statistical analysis, modeling and active multifactorial experiment were used. The results obtained can be used by logging, wood processing and agricultural enterprises to obtain additional raw materials for the production of semi-finished products and materials, as well as in the design of new types of equipment.

Определение зависимости кажущейся плотности керамических образцов от формовочной влажности глинистого сырья и давления прессования на основе регрессионных моделей

The paper proposes to use white clay with the highest apparent density to improve the production of wire-ceramic resistors. Preliminary studies of white clay have shown that it is more sensitive to drying than red clay. The intensity of moisture output from the center of the product to its surface during the manufacturing process and the drying characteristics of white clay give greater shrinkage and strength of dry samples. Linear and nonlinear multiple regression models with and without multicollinearity are considered to find the dependence of the apparent density of clay raw materials on humidity and pressing pressure. To clarify the model structures, a two-stage approach is used, which involves building a model for residuals. It is found that the combination of a multiple regression model taking into account multicollinearity with an AR model constructed for residues makes it possible to calculate the apparent density of clay raw materials with the smallest standard deviation from experimental data. The obtained model structures will be used to determine the optimal parameters of forming ceramic samples: the moisture content of clay raw materials and the compaction pressure, at which the greatest apparent density of samples is achieved. This will improve the production technology of wire-ceramic resistors. The use of wire-ceramic resistors based on white clay with the highest apparent density will speed up one of the stages of the technological process – drying and reduce their hygroscopicity. As a result of the use of wire-ceramic resistors with the highest apparent density, the mechanical strength of the products will increase, which will improve the operational characteristics and prolong the life of the products.

Development of Optimal Technology for Drying Herbal Medicinal Raw Materials from Autumn Wormwood (<i>Artemisia serotina</i> Bunge) Based on Comparative Analysis

Introduction. Choosing the optimal method for drying medicinal plants is an important aspect of obtaining herbal materials of pharmacopoeial quality. At the site of the pharmaceutical enterprise Fitoleum LLP (Esik, Kazakhstan), a technology for obtaining herbal materials from autumn wormwood (Artemisia serotina Bunge) was developed, within the framework of which the optimal drying method was studied using IR radiation, convective drying and shadow drying in natural conditions. In parallel with the experimental approach, a method for simulating drying conditions was implemented. The development of technology for the obtaining of herbal materials is implemented using the "Quality by Design" concept, one of the principles of which is the modeling of experiments (Design of experiments, DoE). The advantage of modeling when studying the processes is that this technique allows you to simultaneously analyze several input parameters and their impact on quality indicators, while significantly reducing the number of experiments.Aim. To choose the optimal method for drying autumn wormwood herb for further production of herbal medicine or herbal materials.Materials and methods. During the experiment, the following equipment was used: a manual harvester for collecting plants, pallets or racks with a mesh bottom, infrared substrates, a convective drying oven, racks with pallets under a canopy in natural conditions, a grass cutter, vibrating sieves. Also, the study was carried out in accordance with the principles of the "Quality by Design" concept using the Minitab Statistical Software 21 program, using a statistical tool – Design of experiments (DoE).Results and discussion. The results of studies of various drying methods have shown that the most optimal is drying with IR radiation, which allows to maintain the content of essential oils (the main group of biologically active substances) at the optimal level – about 1,7 % with a raw material moisture content of no more than 13 %. The data obtained by simulating the experiment in the Minitab program were comparable to the results of the classical experimental design. The optimal method and technological parameters for drying autumn wormwood have been established – the use of IR radiation, temperature of 35–45 °C and drying time of 14–17 hours. Comparable data on the studied technological parameters of three sequentially produced series were obtained and the validity of the technological process for drying autumn wormwood was confirmed.Conclusion. Comparative analysis of the methods of drying medicinal plants – IR radiation, convective and shadow drying in natural conditions – of autumn wormwood (Artemisia serotina Bunge) was carried out. It has been established that the maximum content of essential oils (as the main group of biologically active substances) in raw materials is observed when using drying using IR radiation at a temperature of 35–45 °C for 14– 17 hours. At the same time, the residual moisture content of the drug is no higher than 13 %, which corresponds to pharmacopoeial requirements. Conducted studies of predicting optimal drying parameters using the Minitab Statistical Software 21 program showed comparability with the experimental results. Based on the results obtained, an optimal method for drying autumn wormwood herb was proposed for use in production and obtaining pharmacopoeial quality medicinal products.

Utilization of grape waste with different moisture content as fuel briquettes

AbstractIn 2020, world fresh grape production increased to 78.03 million metric tons from 77.00 million metric tons in 2019. Approximately 80% of the grapes produced in the world are consumed as wine and fruit juice. In such a large industry, a huge amount of waste is generated after processing. This waste is generally used as fertilizer and burned inefficiently. In this study, the quality and strength parameters of the briquettes obtained were determined in order to investigate the possibility of using grape wastes as fuel briquettes by compressing them under constant pressure (120 MPa) at three different moisture content levels (6.8%, 9.4%, 12.1%) instead of using them as fertilizer or burning them inefficiently. As a result of the study, it was determined that the compression force, compression stress, specific compression force, and quality parameters such as density, water resistance, tumbler, and shatter index of the briquettes obtained from the briquettes with 6.8% raw material moisture content were in accordance with the international standard, ISO 17225‐3.

A Review of the Parameters Related to the Rubber Sheets Production: Major Constituents of Rubber Latex, Rubber Particles, Particle Interaction of Rubber Latex, Rubber Porous Structure, Rubber Drying Kinetics and Energy Consumption

Natural rubber (NR) is obtained principally from Para-rubber trees of the species Hevea brasiliensis which grow in tropical regions. Using ultra-centrifugation method, fresh latex (FL) from Para-rubber trees can be mainly divided into four fractions; an upper white layer consists of rubber particles, Frey-Wyssling particles in a yellow or an orange layer, C-serum phase and lutiods particles in the bottom fraction [1-3]. The averages of rubber particles have diameters of 0.02 to 3.0 micron, and they are protected by a complex film containing lipids and proteins [4-8]. The main forces of attraction between neighboring rubber particles in latex system can be divided into five force types; Structural Forces (SF), Van der Waals Interaction (VWI), Electrostatic Force (EF), Exclusion Interaction (EI) and Polymer-Polymer Interaction (PPI) [9]. The porous model of rubber structure used to describe moisture transfer was based on the existence of two different regions referred to as non-hygroscopic region and hygroscopic region. The rubber products drying always produced a considerable shrinkage effect which considered in the physical of the product, such as the diffusion coefficient, mass and heat transfer. An initial moisture content of raw material, the experimental temperature and the drying equipment had affect to the EMC isotherms and the drying kinetics. Finally, discussions on the implications of the results for strategies to reduce the energy consumption in RSS and STR20 block rubber are also presented.

Оптимизация процесса работы пресс-гранулятора соевой половы

To determine the optimal design parameters and modes of operation of the screw-type pelleting press, the authors studied the granulation of soybean chaff fractions pre-crushed to 5 mm with the addition of soybean grains as a binder. The pelleting process was stable at a temperature of the pelleting press barrel of 70…80°С and the temperature of pellets at the exit of 65 to 70°С. Humidity control was carried out in accordance with GOST 13496.3-92, the crumbling of pellets - in accordance with GOST 23513-79, GOST 22834-87. Fifteen experiments were carried out in three repetitions according to the matrix of the orthogonal central composition plan of the second order. The factors of the experiment included the matrix thickness, the moisture content of the raw material and the mass fraction of soybean grains in the raw material. The crumbling of the obtained pellets served as the optimization criterion. Based on the experiment results, an adequate regression equation was obtained. It was established that the smallest percentage of pellet crumbling is observed in the moisture content ranges of raw materials of 50 to 60% and the mass fraction of soybean grinding in raw materials of 15 to 16.5%. With a fi xed value of raw material moisture content, the optimal thickness of the pressing matrix corresponds to the range of 27.5 to 39.0 mm, while the mass fraction of soybean grain in the raw material is 15 to 25%. With a fi xed mass fraction of soybean grain, the optimal values of the pressing matrix thickness range between 30 and 40 mm, the values of the initial moisture content are 40 to 60%. To obtain pellets consisting of pre-crushed and moistened soybean chaff and soybean grains with the crumbling rate of less than 12%, the thickness of the matrix with holes with a diameter of 10 mm should be 30 to 40 mm, the mass fraction of soy in the raw material should correspond to 15 to 16.5%, and the moisture content of raw materials should equal 51 to 60%.

Automatic shoe drying oven integrated with Raspberry Pi Cloud system for advanced footwear industry

The drying oven functions to reduce the moisture content of raw materials until it reaches a certain moisture content to slow the rate of product damage due to biological and chemical activity. This research aims to design an automatic shoe-drying oven equipped with an LCD screen, exhaust fan, 8-level shelf, and electric heating temperature controller to provide maximum and even heating of leather shoes when gluing and drying leather shoes. Raspberry PI aims to combine and collect production process data in cloud storage in the form of a database, which will then be sent and displayed directly to the operator. The research methodology includes design, manufacturing, assembly, operational testing, performance testing, and evaluation stages. It can be concluded that the research results and progress reports include: (1) The design of the work system and mechanical system for the shoe drying oven can work well. (2) The Raspberry PI Cloud system can collect and display actual drying time data, (3) glue drying temperature of 60°C with a drying time of ±5 minutes, (4) skin heating temperature (texture creation) of 50°C-55°C requires warm-up time ±40 minutes, (5) This machine requires 850 watts of power.

Parameters of Agricultural Product Dryer

The problem of drying quality in existing installations is considered. It is proposed to carry out the analysis of heat and moisture transfer in the Comsol complex. As a result of modeling, dependences of changes in temperature and moisture content of raw materials on time were obtained. A rational geometry of the location of the dryer trays and the addition of convective heating with an IR emitter are recommended, which contributes to the formation of a more uniform moisture content of the dried product and a reduction in the process time.

Контроль качества активированного угля методом ядерного магнитного резонанса

The production of activated carbon by pyrogenetic decomposition is a complex high-temperature process that involves several stages. The quality of the produced activated carbon primarily depends on the moisture content of raw material and the degree of removal of impurities from the solid carbon residue, operational assessment of which is rather difficult due to the production specifics. The use of NMR relaxometry methods can significantly speed up the process of measuring these parameters in at-line, on-line and in situ conditions. The research aims at determining the absolute moisture content of the raw material, intermediate and finished products, as well as controlling their pyrolysis degree at different stages of activated carbon production via proton density. Samples of the lignocellulosic group (from wet raw material to the finished product) were the research objects. NMR experiments with the Magic Sandwich Echo (MSE) pulse sequence were carried out for measuring the moisture content and proton density of the samples. The study revealed an unambiguous correlation between the values of proton density and the pyrolysis degree of the samples. The experimental results can be used in further improvement of the proposed methods for estimating the specified parameters. It was found that the MSE experiment makes it possible to determine quite accurately the moisture content in both the initial plant raw material and the carbonization products, including activated carbon. The paper presents data on the dynamics of changes in the proton density of samples of plant raw materials during thermal decomposition. A direct correlation was found between changes in the proton density of the samples and their specific density during thermal processing. The proton density of the raw material samples has different values, while the proton density of the carbon samples varies much less. This observation shows that chemicals are being removed from the samples, causing the proton density to decrease. The research results will improve the systems of intermediate and final control in the process of obtaining activated carbon by thermal processing.

Potential of some Latvian Industrial Crops Residuals for Conversion to Bio-Based Thermal Insulation Material

Some industrial crops residuals like wheat straw, buckwheat husks and reeds were used in the study as raw lignocellulosic materials to evaluate their potential as thermal insulation material. Steam explosion (SE) pre-treatment was used to disrupt and convert the raw material smooth shape to foamy fibrous shape. Two level Factorial design was used to evaluate the impact of raw material fraction size (10-20-30 mm), moisture content (10-30-50%), SE temperature (200-215-230 °C) and duration (00-30-60 s) on bulk density and thermal conductivity of the obtained loose-fill materials. The results show that all selected raw materials could be characterized as thermal insulation materials as the determined thermal conductivity was in the range of 0.042–0.058 W (m K)-1 including neat samples. In spite of effective fibrillation of raw materials SE pre-treatment did not improve their thermal conductivity. The determined bulk density of loose-fill crops varied in range of 23–184 kg m-3 depending on all variables; the SE pre-treatment showed the most significant effect on its reduction. Based on the study results the most suitable crops residues for bio-based thermal insulation purposes are suggested wheat straw and reeds demonstrating the lowest values of bulk density and thermal conductivity.

Actual prospects of using some types of larch growing in Kazakhstan in medicine

Local plants can save natural resources and be used as a source of biologically active compounds, which can be high-quality, effective, and safe ingredients for pharmacological or chemical industries. Therefore, this study aimed to investigate the properties of two medicinal plants – the fine-scaled larch (Lárix Kaémpferi) and Siberian larch (Lárix Sibirica), which are growing in the Republic of Kazakhstan. We compared the two types of larches according to botanical affiliation and species description. We studied the alcoholic extracts from Lárix Kaémpferi and Lárix Sibirica to determine their physical and chemical properties. The data on the chemical composition of extractive compounds were generalized and systematized. The authenticity of Lárix Kaémpferi and Lárix Sibirica was established by external, anatomical, and diagnostic signs in microscopic examination and qualitative reactions. Specific indicators and their norms for raw materials were identified. This is the standard for both types of larch and determines their quality. We experimented with grinding fineness for studied materials and tested the impurities and moisture content of raw materials, total ash, and ash insoluble in a 10% hydrochloric acid solution. Determination of heavy metals and radionuclides was also considered. The quality specifications were developed based on the standardization of fine-scaled larch and Siberian larch.

Diversifikasi dan Optimalisasi Pengolahan Kulit Salak melalui Perlakuan Suhu dan Durasi Penyeduhan

Salak is only used for the flesh of the fruit, for the peel and seeds of salak, it has not been widely developed into a product and only becomes waste. Consumption of peel is generally made in the form of extracts such as tea, where the peel is dried and then after drying it is mashed into powder and brewed using hot water. The use of hot water needs to attention to the temperature and brewing time because it can affect the amount of nutrient content in the peel tea. The temperature and brewing time affect the direct contact between water and the peel extract powder. The temperature used is 80,90,100 (oC) with a time of 5,7,10 (minutes). The analyzes carried out were analysis of raw material (moisture content), analysis of brewing quality, and chemical analysis (antioxidants, caffeine, tannins, and total sugar). The results showed that the best results were at 80oC for 10 minutes, the antioxidant content was 500.57 mg/ml, caffeine 0.65 mg/ml, tannins 1.35 mg/ml. The 80oC temperature treatment with a time of 7.5 minutes resulted in the highest total sugar content of 3.06%

Resource-saving perspectives of using sunflower stalks for the development of functional foods

The chemical composition of Heliánthus ánnuus sunflower stalks has been studied. A technology has been developed for obtaining an extract from a sunflower stalk The study determined the moisture content of raw material, mass fraction of easily hydrolyzable polysaccharides, mass fraction of hardly hydrolyzable polysaccharides, as well as the content of extractive substances and the content of tannins.

Quality risk analysis of cocoa agroindustry: a case study in Pesawaran District, Lampung Province

Quality is a critical issue in small and medium scale cocoa agroindustry, which affected competitiveness significantly. Product quality is strongly influenced by implementing best practices in cocoa production and processing. This study aims to identify quality risks, analyze risks, and develop risk management strategies in the cocoa agroindustry using a case study. Analysis used Quality Risk Matrix to map the risks and Analytical hierarchy process to develop a quality risk management (QRM). The results showed that blooming is the highest quality risk, followed by taste differences, moisture content of raw materials, and color differences. From the management aspect, QRM in the cocoa agroindustry includes documentation system management, implementation of training regularly, implementation of internal audit, periodic reviews, impact assessment, development reports and controls verification, and development of an integrated supply chain systems. QRM includes providing facilities, maintenance of equipment and utilities, material management development, packaging and labeling, and continuous production methods from the technical side. The implementation of QRM in the cocoa agroindustry is carried out through improvements in the production process. In addition, the implementation of QRM requires support from the government and other stakeholders in the cocoa value chain.

New insight into the impact of moisture content and pH on dissolved organic matter and microbial dynamics during cattle manure composting

Composting is an effective way to treat agricultural waste, whereas inappropriate initial conditions could cause lower maturity and system instability. In this study, the dissolved organic matter dynamics and microbial community succession of cattle-manure composting were investigated under different initial moisture content (MC) and pH of raw material. The results indicated that the extended duration of thermophilic phase and the highest GI (germination index) value of final product were observed at matrix 60% MC and pH 8.5 (AT2 treatment). Microbial analysis showed that the succession of bacterial and fungal community was significantly influenced by total carbon (TN), pH and MC (P < 0.05). The relationship between microbial community and fluorescence regional integration (FRI) parameters demonstrated that Thermobifida (bacterial genus), Mycothermus and Thermomyces (fungal genera) were positively correlated with PV, n (the integral aera of Region V). This study could provide a potential strategy for large-scale industrial application of compost.

Cyclone Rotational Drying of Lignite Based on Particle High-Speed Self-Rotation: Lower Carrier Gas Temperature and Shorter Residence Time

The high moisture content of lignite raw materials leads to its low combustion efficiency and large CO 2 emissions. Therefore, the drying of lignite are the keys to achieving efficient and clean utilization, and further realizing energy-saving and emission-reduction. In this study, based on coupling centrifugal effect of high-speed self-rotation and revolution of particles in cyclone, low-energy consumption and high-efficiency lignite cyclone rotational drying was realized at a low carrier gas temperature (lower than 100°C) and in a short residence time (less than 10 s). The influence of operating parameters and structure parameters on lignite drying efficiency were investigated, when carrier gas temperature was 80 °C, the moisture content of lignite can be reduced from 45.1% to 15.2% after single-stage cyclone drying in a 75 mm diameter cyclone. When the diameter of the cyclone was expanded to 100 mm, the single-stage dehydration efficiency can be increased to 75.8%. Compared with the fixed-bed evaporative drying, the cyclone rotational drying can increase the drying rate and reduce the drying time and energy consumption. It is revealed that the cyclone rotational drying method provides a new idea for the lignite drying technology, and can serve as guidance for industrial applications.

Substantiation of the basic constructive-and-technological parameters of technology for preparing haylage of the cocksfoot (Dactylis glomerata L.) using gas preservative

The most important task for the further development of animal breeding is increase of production of feed, increase of its quality and reduction of production costs. Important thing in these conditions is the parallel development of two areas - creation of highly productive agrocenoses and development of technologies capable of saving the obtained feed mass for future use during winter period. A valuable component in grass mixtures when creating highly productive hayfields in the North-West region is the cocksfoot (Dactylis glomerata L.), which in the North conditions forms rather high yield of feed mass, as soon as it responds to fertilizer application properly. On the basis of the Institute of Agrobiotechnology Federal Research Center Komi Scientific Center Ural Branch of the Russian Academy of Sciences (Russia, Komi Republic, Syktyvkar), a device has been developed for treating haylage by carbon dioxide. To determine the efficiency of this technique when harvesting haylage of cocksfoot, two series of experiments were carried out - laboratory and field. In the course of the laboratory experiment, we conducted an experiment according to the Box-Behnken plan of the second order for four factors with three levels of variation. The optimal parameters of the device were determined as a result: density of raw materials; volume of raw material processed by one spray nozzle; gas preservative consumption and its dose. In the field experiment, haylage was processed in rolls according to certain optimal parameters. The feed obtained was compared in terms of quality with haylage prepared of the same raw material in compliance with standard technology, but with no preservatives. As a result of the studies, it has been determined that carbon dioxide is most effective when harvesting the cocksfoot as raw material for haylage, with the following parameters: density of pressing the hay mass - 290-330 kg/m3 ; moisture content of raw materials - 53-55 %; dose of carbon dioxide introduced into the haylage - (0.40-0.50)∙10-3 m3 /kg; carbon dioxide consumption through a gas supply reducer 0.500.60 m3 /h. This provides an increase in feed units in one kilogram of feed by 0.3, exchange energy - by 0.4 MJ, digestible protein - by 1 g.

Ways of improvement of technological equipment performance

Increasing of production performance of production systems and equipment in the meat-processing industry is integrally linked to maintenance activities. The article analyzes the influence of technological effectiveness, level of hygiene, reliability and simplicity of equipment design on the main parameters of meat products quality. Here it is shown that the strategy of Total Productive Maintenance (TRM) and Lean production is important tool for assessment of parameter of the Overall Equipment Effectiveness (OEE), which is used to assess the main types of losses that reduce the equipment productivity. The link of influence between the structural and mechanical properties of food masses, the moisture content of the initial food raw material, the temperature and viscosity, the processing pressure, and the density for the optimal operating terms of the equipment are analyzed in this research. With the help of OEE concept, the time losses related to the features of the equipment functioning are determined. The types of losses are classified as follows: downtime and readjustment (availability or readiness for operation) of equipment, short-term shutdown of equipment and a decrease in processing speed (productivity or performance rate of the equipment), product rejects and product losses (quality losses) during startup of equipment. While analyzing of the operation of vacuum filler for sausages production, the values of parameters of equipment availability, it productivity and product quality are calculated. The availability index is 0.79, the productivity index is 0.76, and the product quality index is 0.95. Taking into account the obtained data on equipment availability, productivity and product quality, it is determined that the overall equipment effectiveness (OEE) accounts for 57%. The application of this method for studying the overall equipment effectiveness operation can be applied to any technological equipment used in the meat-processing industry and allows eliminating many problems that arise during the operation of technological equipment, improving its technical and economic parameters, and developing a system of measures for improvement of its maintenance and repair.