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

Effective Robotics Education: Surveying Experiences of Master Program Students in Introduction to Robotics Course

© The Authors, published by EDP Sciences, 2018. Technology-driven world poses new challenges for the modern education system. To prepare skilled specialists for academic and industrial needs it is important to create competitive educational ground. Our team works on developing and implementing world-class master program in Intelligent Robotics. To pave the way for a high-quality educational program we invest efforts into studying students' attitude and motivation for connecting their professional life with robotics. In this paper we describe the curriculum for master program that was designed and implemented at the Higher Institute of Information Technology and Information Systems at Kazan Federal University and present the results of our continuous research of comparative analysis of surveys among students of Introduction to Robotics course

Experimental and Theoretical Investigations of a Ground Source Heat Pump System for Water and Space Heating Applications in Kazakhstan

The ground source heat pump heating system is considered as one of the best solutions for the transition towards green heating under the continental climate conditions like Kazakhstan. In this paper, experimental and theoretical investigations were carried out to develop a ground source heat pump-based heating system under the weather conditions in Kazakhstan and to evaluate its thermodynamic performance. The water-to-water heat pump heating system, integrated with a ground source heat exchanger and used refrigerant R134a, was designed to provide hot water to meet the requirements for space heating. The predicted values of the coefficient of performance and the experimental results were found to be in good agreement within 6.2%. The thermodynamic performance of the system was also assessed using various environment-friendly refrigerants, such as R152a, R450A, R513A, R1234yf and R1234ze, as potential replacements for R134a. Although R152a is found to be a good alternative for R134a in terms of coefficient of performance and total equivalent warming impact, its flammability hinders its application. The heating system using refrigerants R450A, R513A, R1234yf and R1234ze shows 2–3% lower coefficient of performance than that of R134a. The highest exergy destruction is found to be attributed to the compressor, followed by the expansion valve, evaporator, and condenser. Considering their low flammability and low environmental impact, R450A, R513A, R1234yf and R1234ze are identified as valuable replacements for R134a

Stability and collisions of moving semi-gap solitons in Bragg cross-gratings

We report results of a systematic study of one-dimensional four-wave moving solitons in a recently proposed model of the Bragg cross-grating in planar optical waveguides with the Kerr nonlinearity; the same model applies to a fiber Bragg grating (BG) carrying two polarizations of light. We concentrate on the case when the system's spectrum contains no true bandgap, but only semi-gaps (which are gaps only with respect to one branch of the dispersion relation), that nevertheless support soliton families. Solely zero-velocity solitons were previously studied in this system, while current experiments cannot generate solitons with the velocity smaller than half the maximum group velocity. We find the semi-gaps for the moving solitons in an analytical form, and demonstrated that they are completely filled with (numerically found) solitons. Stability of the moving solitons is identified in direct simulations. The stability region strongly depends on the frustration parameter, which controls the difference of the present system from the usual model for the single BG. A completely new situation is possible, when the velocity interval for stable solitons is limited not only from above, but also from below. Collisions between stable solitons may be both elastic and strongly inelastic. Close to their instability border, the solitons collide elastically only if their velocities c1 and c2 are small; however, collisions between more robust solitons are elastic in a strip around c1=-c2.Comment: 16 pages, 7 figures, Physics Letters A, in pres

The relationship of cytokine status with left ventricular hypertrophy in patients with arterial hypertension

Aim. To study the relationship of tumor necrosis factor α and interleukin-10 levels with the presence of left ventricular hypertrophy and myocardial remodeling in patients with arterial hypertension. Metods. 156 patients with hypertension aged 40 to 75 years (mean age 55.8±7.5 years), including 57 women and 99 men were examined. All patients were divided into two groups. Group 1 included 83 patients without left ventricular hypertrophy (55.5±7.5 years), group 2 included 73 patients with left ventricular hypertrophy (56.2±7.8 years), established by echocardiographic signs. All patients in addition to the general clinical examination and biochemical studies had echocardiography and Doppler echocardiography performed, as well as measurement of the concentration of tumor necrosis factor α and interleukin-10 by solid-phase enzyme immunoassay using specialized «Cytokine-Stimulus-Best» kit (Novosibirsk, Russia). Results. The concentration of tumor necrosis factor α in patients without left ventricular hypertrophy was 8.43±1.36 pg/ml and was comparable with the concentration of this cytokine in patients with left ventricular hypertrophy (8.54±1.58 pg/ml, p >0.05). This pattern was typical for both men and women. The concentration of interleukin-10 in both groups was also comparable (15.4±3.6 pg/ml in group 1 and 14.7±3.4 pg/ml in group 2, p >0.05). However, we identified gender-specific features in the relationship of interleukin-10 with the presence of left ventricular hypertrophy in patients with hypertension. Thus, while in women the concentration of cytokine in groups with/without left ventricular hypertrophy did not differ significantly, in men without hypertrophy the level of interleukin-10 of 15.7±3.6 pg/ml, was significantly higher than the value of the same indicator in the group of men with left ventricular hypertrophy (14.8±2.9 pg/ml, p <0.025). Multivariate regression analysis showed that tumor necrosis factor α and interleukin-10 concentrations correlated to left ventricular wall thickness in patients without left ventricular hypertrophy. No such pattern was revealed for patients with hypertrophy. Conclusion. The results demonstrate the modulating role of tumor necrosis factor α and interleukin-10 in myocardial remodeling processes in arterial hypertension