Improvement of the Process of Mechanical Dehydration of Five-Layer Semi-finished Wet Leather Products

To improve the process of mechanical dehydration of semi-finished wet leather products, a multilayer dehydration using felt materials – monshons was experimentally investigated. The process is conducted by vertical feed of semi-finished wet leather products on a base plate between rotating squeezing rollers. The D-optimal method of mathematical planning of the experiment and the Kano design matrix were used for conducting experiments. The multi-layer package consists of five layers of semi-finished wet leather products and two layers of moistureremoving materials between each layer, folded over the base plate. The studies were carried out in laboratory conditions on an experimental bench, taking into account the production parameters of processing. As a result of the study, mathematical dependences of the amount of removed moisture for each of five layers of semifinished wet leather product on the feed speed and the pressure of the squeezing rollers were derived. The analysis of the results showed that, with the existing parameters of mechanical dehydration, it was possible to simultaneously squeeze out moisture from five layers of the semi-finished leather product with a minimum pressure of the squeezing rollers and an average feed speed. The productivity of the technological process was more than five times higher in comparison with the productivity of similar roller machines. In the near future, this research methodology will be used to determine the technological factors affecting the extraction of excess moisture from a package consisting of ten semi-finished wet leather products and moisture-removing materials

Improvement of the Process of Mechanical Dehydration of Five-Layer Semi-finished Wet Leather Products

To improve the process of mechanical dehydration of semi-finished wet leather products, a multilayer dehydration using felt materials – monshons was experimentally investigated. The process is conducted by vertical feed of semi-finished wet leather products on a base plate between rotating squeezing rollers. The D-optimal method of mathematical planning of the experiment and the Kano design matrix were used for conducting experiments. The multi-layer package consists of five layers of semi-finished wet leather products and two layers of moistureremoving materials between each layer, folded over the base plate. The studies were carried out in laboratory conditions on an experimental bench, taking into account the production parameters of processing. As a result of the study, mathematical dependences of the amount of removed moisture for each of five layers of semifinished wet leather product on the feed speed and the pressure of the squeezing rollers were derived. The analysis of the results showed that, with the existing parameters of mechanical dehydration, it was possible to simultaneously squeeze out moisture from five layers of the semi-finished leather product with a minimum pressure of the squeezing rollers and an average feed speed. The productivity of the technological process was more than five times higher in comparison with the productivity of similar roller machines. In the near future, this research methodology will be used to determine the technological factors affecting the extraction of excess moisture from a package consisting of ten semi-finished wet leather products and moisture-removing materials

Friction and Wear Characteristics of C/Si Bi-layer Coatings Deposited on Silicon Substrate by DC Magnetron Sputtering

The tribological behavior of carbon/silicon bi-layer coatings deposited on a silicon substrate by DC magnetron sputtering was assessed and compared to that of amorphous carbon and silicon coatings. The motivation was to develop a wear resistant coating for silicon using thin layers of amorphous carbon and silicon. Wear tests were conducted by sliding a stainless steel ball against the coating specimens under applied normal loads in the range of 20 * 50 mN. Results showed that the wear rate of the bi-layer coating was strongly dependent on the ratio of thickness between the carbon and silicon layers. The wear rate of the bi-layer coating with 25 nm thick carbon and 102 nm thick silicon layers was about 48 and 20 times lower than that of the single-layer amorphous carbon and amorphous silicon coating, respectively. In addition, the steady-state friction coefficient of the bi-layer coating could be decreased to 0.09 by optimizing the thickness of the layer. Finally, a model for the wear reduction mechanism of the carbon/silicon bi-layer coating was proposed

Digitalization of education is a requirement of the time

The article discusses the prospects for the development of innovative technologies in the context of the digital transformation of education. The modern directions of research in the field of introduction of innovative technologies in the educational process are analyzed. Examples of software and pedagogical tools are given that allow performing all types of workloads of students.The psychological and pedagogical conditions accompanying the educational process are indicated

Thermodynamics of a Karatau and Aktobe phosphorites mixture interaction when producing phosphorus, calcium carbide and ferrosilicon

Relevance. Associated with the need to increase the level of comprehensive use of phosphorites during their electrothermal processing and to reduce the amount of slag waste generated during the production of phosphorus and polluting the environment. Aim. To conduct computer thermodynamic modeling of the effect of temperature and amount of iron on technological parameters of interaction of a Karatau and Aktobe phosphorites mixture with carbon and iron to produce phosphorus, calcium carbide and ferrosilicon. Objects. Phosphorites of the Karatau and Aktobe phosphorite-bearing basins. Methods. Thermodynamic computer modeling using the HSC Chemistry 6.0 software; rotatable second-order experiment planning technique; geometric optimization of technological parameters. Results. It has been established that depending on temperature in a mixture of Karatau and Aktobe phosphorites with carbon and iron, they participate in interaction:  CaSiO3, SiO2, Si, SiC, SiO(g), MgSiO3, Al2SiO5, Na2SiO3 , Ca(g), CaO, CaC2, CaF2, CaS, Fe, FeSi, FeSiO3, FeP, Fe2P, Fe3P, FeP2, FeO, Fe3Si; Ca3(PO4)2, P2(g), P4(g). An increase in iron amount leads to an increase in the degree of silicon extraction into the alloy, and at 2000 °C reduces the extraction degree of calcium in CaC2 and the silicon concentration in the alloy. Branded calcium carbide with a volume of more than 230 dm3/kg and ferrosilicon FeSi25 are formed from a mixture of phosphorites, carbon and iron at 2077...2088 °C in the presence of 20...21.4 % iron and 43 % carbon (in this case, phosphorus is completely distilled off into the gas phase). Using our proposed method of electric smelting of phosphorites with phosphorus distillation and associated production of ferroalloy, in comparison with the traditional method, the indicator of integrated use of raw materials increases from 43.9 to 62.7...73.6 %, that is 1.43...1 ,67 times. The proposed processing technology helps to increase active reserves of phosphorites and bring low-grade phosphorites of the Aktobe basin into production

Characterization of the near-surface nanocrystalline microstructure of ultrasonically treated Ti-6Al-4V using ASTAR™/precession electron diffraction technique

The surface of Ti-6Al-4V was treated mechanically by applying ultrasonic nanocrystal surface modification. The effect of this treatment on the hardness, compressive residual stresses and fatigue performance were investigated. It is shown that in terms of the measured nanoindentation hardness values and the presence of compressive residual stresses, the treated sample only differed from the as-received sample in the first 200–300 µm area far from the surface. Also, the microstructure very close to the treated surface (\u3c5 µm) was characterized using a relatively new transmission orientation microscopy technique named ASTAR™/precession electron diffraction. Based on different types of results (e.g., index map and virtual bright field image) acquired by this technique, it is concluded that titanium grains smaller than 10 nm exist within the distance of less than 1 µm from the treated surface. Difficulties associated with ASTAR™/precession electron diffraction technique to characterize this challenging near-surface area are discussed

Laser decoating of DLC films for tribological applications

Damaged DLC coatings usually require remanufacturing of the entire coated components starting from an industrial chemical de-coating step. Alternatively, a complete or local coating repair can be considered. To pursue this approach, however, a local coating removal is needed as first operation. In this context, controlled decoating based on laser sources can be a suitable and clean alternative to achieve a pre-fixed decoating depth with high accuracy. In the present study, we investigated a laser-based decoating process executed on multilayered DLC films for advanced tribological applications (deposited via a hybrid PVD/PE-CVD technique). The results were acquired via multifocal optical digital microscopy (MF-ODM), which allowed high-resolution 3D surface reconstruction as well as digital profilometry of the lasered and unlasered surface. The study identifies the most critical process parameters which influence the effective decoating depth and the post-decoating surface roughness. In particular, the role of pulse overlap (decomposed along orthogonal directions), laser fluence, number of lasing passes and assist gas is discussed in text. A first experimental campaign was designed to identify the best conditions to obtain full decoating of the DLC + DLC:Cr layers. It was observed that decreasing the marking speed to 200 mm/s was necessary to obtain a sufficient pulse overlap and a nearly planar ablation profile. By operating with microsecond pulses and 1 J/cm2 (fairly above the ablation threshold), less than 10 passes were needed to obtain full decoating of the lasered area with an etching rate of 1.1 μm/loop. Further experiments were then executed in order to minimise the roughness of the rest surface with the best value found at around 0.2 μm. Limited oxidation but higher Ra values were observed in Ar atmosphere

Modeling of strain and filtration properties of a semi-finished leather product

Abstract A study on deformation and filtration properties of a leather semi-finished product after chrome tanning are presented. The analytical dependences of compressive load on compressive (recovery) strain and moisture content of a leather semi-finished product are obtained. The empirical dependences of hydraulic gradient on filtration rates are determined for various compression ratios of the leather semi-finished product. It was revealed that with an increase in compressive load and moisture content of the leather semi-finished product, the compressive deformation increases. The shoulder section is subject to the greatest deformation, then the belly section and the least deformation is observed in the butt section. A linear relationship has been established between the hydraulic gradient and the rate of moisture filtration through the leather semi-finished product in the directions perpendicular and parallel to its surface. Graphical abstrac

INFLUENCE OF DIFFERENT HERBICIDES AGAINST WEEDS MEETING ON CEREAL FIELDS UNDER IRRIGATION

Grain production has been and remains the basic branch of agricultural production of each state. In stabilizing grain production, plant protection from pests, diseases, and weeds is of great importance. The article discusses the effect of various weeds found in grain fields on grain yield and their impact on herbicide treatment. The study revealed the type and number of weeds before and after spraying with herbicides

Fatigue lifetime of AlBC(3) alloy by ultrasonic fatigue testing machine in cavitation regime

In this study, the influence of ultrasonic nanocrystalline surface modification (UNSM) technique on the cavitation fatigue properties of AlBC(3) alloy was investigated. The fatigue properties of the untreated and treated specimens were assessed using an ultrasonic fatigue testing (UFT) machine. The treated specimens exhibited longer fatigue life in comparison with those of the untreated specimens, which may attributed to the plastically deformed layer at the top surface of the treated specimen. Also, a fracture analysis was studied using a scanning electron microscopy (SEM) to shed light on the fracture behavior of the specimens