Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The combination of different qualities of leather waste with different polymers and the resulting mechanical properties are potentially important for obtaining new materials. In this study, experiments combining leather chip residue, vinnapas ®400 resin and distilled water produced a new composite material with interesting mechanical properties. In the elaboration, the pH of the leather chip, chip size, resin temperature, softening temperature, pressure and the pressing time exerted on the reconstituted leather plate were controlled. Using fractional factorial design, the influence of the selected independent variables was determined: chip size, chip/resin ratio, percentage of water, resin temperature, pressure and pressing time on the mechanical properties of the composite material. The experimental results showed that there was a main effect of the Chip/Resin ratio variable at its minimum value on the maximum traction effort, reaching a value of 2,657 MPa. Additionally, in the mechanical creep test, it was found that the composite material called reconstituted leather shows a viscoelastic behavior, which resembles the behavior of tanned leather.

The work aims to develop a model of income taxation that allows strengthening the fiscal effect of personal income tax and reducing the differentiation of income levels of different segments of the population, as well as assessing the impact of the proposed model on social inequality in Russia. To achieve this goal, a special two-parameter model of progressive income tax was developed, reflecting the result of studying the features of modern Russian taxation in the context of personal income tax. The key advantage of the developed tax model is the ability to assess social differentiation (by income category) in a pairwise subdecile breakdown, which allows the state to conduct a more balanced policy concerning each of the income groups participating in the study, which can be expressed, for example, in granting special tax preferences to decile groups that need it.

In the present study NBO method  contain the HOMO and the LUMO energies are calculated for 10 different heterocycles anticancer drug using B3LYP/6-31G(d,p). Frontier molecular orbitals (HOMO and LUMO) and Molecular Electrostatic Potential map of the compound was produced by using the π stacking of structures and anticancer activity of molecules. The NBO analysis was suggested that the molecular system contains π- π interaction, strong conjugative interactions and the molecule become more polarized owing to the movement of π-electron cloud from donor to acceptor. NBO, HOMO and LUMO energies, were investigated and Anticancer activity of Aromatic Heterocyclic compounds was investigated by NBO study and result was compared with our previous study about NICS and S-NICS of these 10 anticancer drug. the HOMO/LUMO gap of the heterocycle anticancer drug is significantly different from each other. The NBO method is used in both symmetric and asymmetric molecules and provides accurate information on the aromatics of the compound, especially the heterocyclic rings. It also provides accurate information in protected areas. Molecule 8 has the highest amount of HOMO and therefore aromaticity among the studied compounds which confirms the result of molecular orbital examination.

The main purpose of this article is to assess the level of trust in the Vladivostok State University of Economics and Service (after this referred to as VSUES) among business structures. To achieve this goal, the following research methods were used: information and comparative analysis, content analysis, survey method, expert assessments, rating, hierarchy analysis method, and index method. The information base of the research was made up of the mission and development strategy of the university, the analytical materials based on the monitoring results of the university effectiveness in 2016-2019, statistical and analytical information posted on federal and regional portals. After the step-by-step assessment, it was revealed which trust criteria of VSUES are insufficient and satisfactory. Based on the analysis of the calculation results, the proposals were formulated that contribute to entrepreneurs' trust level increase in the university.

Carbon bonds are a management tool that is being implemented globally to reduce CO2 emissions into the environment, through forest, soil and water conservation protocols. It forms a main part of the commitments made in the Kyoto Protocol to reduce global warming. For its part, the state of Quintana Roo is a pioneer in the incursion of carbon bonds at the micro-basin level, and where sustainable tourism is consolidated as a preponderant activity catapulted by the spill over effect of the Mayan Train Megaproject, however; the lack or inadequate environmental planning could produce deleterious effects. In this sense, they have been allocated by assembly agreement in 2019 (35 thousand Ha) of tropical forest as ANP. With the technical support of specialists (UTCalakmul), the total biomass, carbon storage and fixation in PF and SAF were estimated as a mitigation indicator according to IPCC. Total height and DBH of trees with DBH≥10 cm and D30 in the case of timber trees were measured. BA was estimated using allometric methods and with biomass expansion factors. The average fixation rate was 5.9 t C/ha/year and the FPs stored up to 70 t C/ha. The participation of the ejido in caring for the forest, soil and water in collaboration with NGOs led to the issuance of the bonds as of August 15, 2021. The results obtained demonstrate the importance of these mechanisms for the promotion of soil, water and forest conservation in Quintana. Roo. And that the integral participation in community projects by academics, NGOs and community members is viable and feasible.

Improving the efficiency of technological tillage methods is primarily associated with developing existing tools and creating new types of working tools for tillage machines. Tillage efficiency improvement depends on the correct choice of the most energy-efficient working tools belonging to the same class of the technological process. This research aims to develop scientific baselines for choosing energy-efficient working tools of different structural designs based on the criteria of power consumption and quality of shallow tillage. The object of this research includes working tools for shallow and deep tillage. The research subject is the changes in the criteria chosen to evaluate the working tools’ efficiency. We involved mathematical modeling based on laws of science observed during tillage, carried out experiments and analyses, and summarised the experimental findings. The scientific novelty of this research justifies the criteria for evaluating the efficiency and quality of working tools used for shallow and deep tillage. The research relies on graphical and empirical dependencies describing the trends in efficiency evaluation criteria for tillage working tools with various operation speed modes. We discovered that to evaluate the efficiency and choose the most energy-efficient tillage working tool, one should use a system of criteria: specific tractive resistance of the active frontal area, terra-dynamic resistance coefficient, and the primary tillage quality parameters. The probability of compliance of the mean values of calculated and experimental findings (0.51–0.87) confirms the adequacy of proposed mathematical models describing changes in specific tractive resistance per unit of active frontal area and terra-dynamic resistance coefficient of tillage working tools. According to the research, when a more energy-efficient tillage working tool is chosen, the working tools under comparison belong to the same class of working tools based on the technological process principle and functioning conditions. Discovered trends in the changes in the efficiency evaluation criteria and the choice of energy-efficient tillage working tools for shallow and deep tillage are represented by empirical dependencies applicable in specific ranges of motion speed under certain functioning conditions. Consequently, we emphasized that further studies should justify the upper and the lower borders of the tillage working tools and terra-dynamic resistance coefficient in accordance with the agrotechnical quality indicators of tillage.

This study aims to justify the possibility of expanding the energy and economic efficiency of a district heating [DH] system. The case study territory is a remote area of the Omsk region (Russia); the method is electric heating. To address this issue, we (1) considered the potential of modernizing these DH systems, (2) analyzed available options, (3) designed the main and auxiliary heat generation equipment, and (4) committed a feasibility study. The design heat consumption was 0.24 MW. To achieve this goal, we suggested two heat pumps; their capacity was 280 kW, and the investment required to install two heat pumps of 150 kW was 2.6 billion rubles. The total capital cost was 4.0 billion rubles. The annual effect after the heat pumps were installed was 0.7 billion rubles. The payback period was 5.6 years; to decrease it, one should install multiple heat pumps on the consumer side. The reason is to avoid heat distribution losses. Replacing traditional DH plants with electric boilers is feasible only if the cost of heat is 6,600 rubles per MWh or above. This cost has already been achieved for several DH plants. Ground source heat pumps are viable at lower prices, approximately 4,100 rubles per MWh. This option is especially helpful in remote areas of the Omsk region where the billing tariff is already high. When modernizing the heat supply infrastructure of the northern areas of the Omsk region, one can increase annual electricity consumption by 6%, decrease tariffs, and become more ecologically friendly at the same time.

The present experimental research study was carried out with the purpose of determining the growth, inhibition or destruction of pathogens on days 0 (t0), 7 (t7), 15 (t15) and 30 (t30); by treatment of HHP 400 and 500 MPa, using the method of quantification or counting of cfu colony-forming units, on three different cocktails of bacteria, such as Listeria monocytogenes, Escherichia coli and Salmonella, the microbial contained in the epicarp or peel of the mango fruit was also investigated. The results in this study show that the application of high hydrostatic pressures, with a treatment of 400 MPa of pressure 8 min of duration, managed to eliminate a load of 5.16 Log, cfu count / gr of the day t0, under conditions of 20 ºC of temperature, on sample of Mangifera indica, var. Kent, with a pH of 3.4, on L. monocytogenes under the same conditions was performed in treatment of 500 MPa of pressure with 8 min of time, having a reduction of 4.64 Log, in a t0, HHP treatments was efficient reducing 6 Log, for t7, t15 t30. Similarly, an inactivation of Salmonella was achieved in t0, for HHP 400 MPa 7.74 Log was eliminated, and in 500 MPa 6.84 Log, for a pure culture with a control load of 9.14 Log, it was observed that, in the case of treatments, they do not present bacterial growth, as several authors argue, causing death by cell damage at times t7, t15, t30.  Likewise, E. coli was studied, for t0, there was a reduction in HHP treatments of 400 MPa of 5.64 Log, for HHP 500 a reduction of 5.04 Log, it was observed that in the treatments there was cell damage in t7, t15 and t30 existing a total reduction, it is concluded that in the case of E. coli according to the data obtained there was a total reduction of bacteria. The microflora of the mango skin was studied, it was established that there was a reduction of 3 Log, on average general for treatments of 400 and 500 MPa for times t0, t7, t15 and t30, observing a resistance for both treatments, due to the presence of yeasts.

Water bodies (e.g., rivers, lakes, and reservoirs) are an integral part of the urban environment. The infrastructure of the city affects their condition, in particular, pollution, including heat, which can lead to an increase in phyto- and zooplankton, including blue-green algae, and the appearance of toxins in the water. Identification of places where warm water is discharged into reservoirs is an urgent task. One of the methods of solving this problem is the monitoring of reservoirs from space. Thus, with the help of infrared satellite images, thermal anomalies are visible. In the work, we studied Lake Kenon located in the city of Chita. The satellite images were obtained from the Lansat-8. The channels used were 10 and 11, with a resolution of 60 meters. We revealed that (1) the optimal time for detecting thermal anomalies is the time before freezing in calm weather; (2) the cause of the thermal anomaly of this reservoir is a thermal power plant; (3) analysis of the last 5 years has shown that the water area with an increased surface temperature of the reservoir does not change; (4) the temperature gradient between cold and warm areas is 5°C; (5) the area of the heat spot does not exceed 10% of the total area of the lake. The above conclusions were confirmed using field measurements.

Pastes of sugarcane bagasse ash (SCBA) and calcium aluminate cement (CAC) were activated with sodium silicate solutions, varying the SCBA content (80-95 wt.%), the SiO2/Na2O ratio (8-14 wt.% respect to the weight of SCBA), and the curing temperature (20 and 40 ºC or 100 and 200 ºC). 28 days-compressive strength between 5-20 MPa were obtained. The results are close to the reported in the literature for pastes of SCBA/metakaolin. Overall, it was observed that the compressive strength decreased with the increase in the curing temperature from 100 to 200 ºC. The gain in the compressive strength was attributed to the formation of a dense matrix of amorphous reaction products such as C-S-H, N-A-S-H, C-A-S-H, or silica gel. Our results stress the feasibility to use higher contents of sugarcane bagasse ash to obtain alkali-activated cement with compressive strengths up to 20 MPa. Further work is currently underway to identify the effect of some variables on the compressive strength of composites.