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SUSTAINABLE BUSINESS MODEL IN THE FIELD OF ONLINE EDUCATION
Get PDFIn recent years, the world education market has changed significantly: in addition to the traditional forms of full-time and part-time education, an innovative approach to education, such as distance learning or Internet learning, is increasingly being adopted. With the current challenges of the pandemic, it has become clear that online education is promising and needs to be developed. The author’s research will help Latvian companies working in the field of online education to analyze the activities of their organization and introduce new measures to increase the sustainability of the business model. Relevance of the work: the author conducts research of the business model during the crisis in order to increase the effectiveness of online schools in accordance with the new realities in the world market
ANTIOXIDANT AND ANTI-CHOLINESTERASE INHIBITION PROPERTIES OF MELISSA OFFICINALIS SUBSP. OFFICINALIS AND LAVANDULA ANGUSTIFOLIA
Get PDFAcetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) inhibitors are promising compounds for clearing up Alzheimer\u27s disease (AD) symptoms. In this study, extracts of Melissa officinalis L. subsp. officinalis and Lavandula angustifolia L. were prepared with different solvents such as methanol, ethanol and distilled water. It was investigated their inhibitory effects on AChE and BChE enzymes. In addition, antioxidant activities and total phenolic contents of plants were determined using the 1,1-diphenyl-2-picrylhydrazil (DPPH) radical scavenging activity method and Folin- Ciocaltau method, respectively. It has been found that the distilled water extract of M. officinalis subsp. officinalis is the most potent inhibitory of both AChE and BChE enzymes among all of the extracts. IC50 values of the extracts were calculated as 1.65±0.04 mg/mL and 2.33±0.03 mg/mL for AChE and BuChE, respectively. On the other tests, the antioxidant activities of methanol extracts of M. officinalis subsp. officinalis and Lavandula angustifolia plants were 95%, and the highest total phenolic content was observed as 2.30±0.30 g/100g in the methanol extract of M. officinalis subsp. officinalis
GEOMETRIC CHARACTERISTICS, COMPOSITION AND STRUCTURE OF COATINGS OF WC-TIB2-B4C- NI-CR-B-SI-C ELECTRODES FORMED ON 3D PRINTING TITANIUM AND STEELS BY CONTACTLESS ELECTROSPARK DEPOSITION
Get PDFThe object of the present work are the surface properties of technical titanium produced by 3D printing - Direct Metal Laser Sintering (DMLS) with subsequent treatment by local electrospark deposition with a rotating electrode (LESD). The layering was performed with electrodes of multicomponent hard alloys based on WC with additives from B4C, TiB2 and Ni-Cr-B-Si-C and of AlSi alloys. The influence of the LESD process parameters on the roughness, thickness, composition and structure of the coatings was studied by profilometric, metallographic, XRD, SEM and EDS methods. High-density coatings with different roughness and thickness have been obtained, which can be changed by changing the LESD modes in the range Ra=1.25÷3.5μm, δ=6÷20μm and microhardness 9÷14.0 GPa. Friction tests have shown that the wear of coated surfaces is up to 4 times lower than uncoated. On the basis of the experimental data, appropriate process parameters and electrodes have been determined, allowing to obtain coatings with purposeful synthesized of new phases and crystal-amorphous structures, and with predetermined thickness and roughness and higher hardness, and wear resistance than those of substrates
FERRITE CONTENT DETERMINATION. METHOD VALIDATION FOR USE IN DUPLEX STAINLESS STEELS: TRADITIONAL VERSUS DIGITAL APPROACHES
Get PDFThe use of duplexes has expanded widely across an extensive number of industries e.g. oil, gas, petrochemical, pulp and recycling, as a structural and engineering material. These steels are mainly used in aqueous environments containing chlorides and as replacements for austenitic stainless steels that have suffered pitting or stress corrosion in service. The properties of these duplex steels depend on the volume fraction (VF) between austenite and ferrite, which is provided by high temperature heat treatment. Duplex stainless steels are intended to present a microstructure composed of similar VF of austenite and ferrite; this is the phase composition leading to the best compromise of mechanical and corrosion properties. The characterization of this volume content is done by readily available metallographic means, as described in the standard ASTM E562 for the measurement of ferrite content by point counting over a significant number of micrographs. This is, however, an outdated and time-consuming approach. The aim of this work is to validate the VF determination method that is more suitable for industrial use, knowledge creation and transfer. Two duplex stainless steels were analysed by two different metallographic approaches (ASTM E562, ASTM E1245), by varying magnification and the number of fields used. Ferrite content and its variability within techniques due to the analytical variables are discussed. Finally, comparison is made between the final values for the ferrite content determined by each metallographic approach. The results highlight the recommendation for the use of the digital automatic image analysis, over the common traditional manual counting point approach. Since the digital approach allows a more efficient and comprehensive process in terms of practical results, simplicity, time and output representativeness of the total volume of the material. Digital automatic image analysis approach can be nowadays more efficiently and accurately used to perform the same analysis
DATA-DRIVEN PROBLEM CLASSIFICATION AND ALGORITHM SELECTION FOR INJECTION MOLDING OPTIMIZATION
Get PDFInjection Molding (IM) is an established and essential production process. Dynamic process changes according to market demands, and advances in additive manufacturing technologies enable both chances and challenges. New molds can be produced more quickly and cheaper, but the demand for ongoing parameter optimization due to the changes in the production process rises. Digital-Twin-based process simulation assists process engineers in estimating optimal parameter settings. Due to its complexity, manual optimization is inefficient. Selecting an appropriate optimization algorithm for this task is challenging. There is a need for automated data science pipelines, especially for small and medium-sized enterprises (SMEs) that often lack algorithm engineering and data science capabilities. This paper addresses the data-driven classification of different IM optimization problems retrieved by IM simulation. As these IM simulations are computationally expensive, we apply Gaussian Process Simulations (GPS) on a small number of samples of the IM simulations to compute cheap to evaluate test problems. We compare a single and a 2-stage variant of GPS, both in their conditional and unconditional forms. The single variant tends to preserve the global characteristics of the problem. The 2-stage variant adds a second simulation model based on the residuals of the first model to simulate the finer local structure of the problem. The retrieved test problems are classified using Exploratory Landscape Analysis (ELA) applied to several minimization objectives of the IM process: max. volume shrinkage [%], avg. volume shrinkage [%], required cooling time [s], max. warpage [mm], max. deformation [mm], and avg. shrinkage [mm]. Finally, benchmark experiments will be conducted to compare optimization algorithms on the test problems and relate the results to the retrieved ELA features. These results build the foundation for algorithm selection and online parameter optimization
CHANGES IN YIELD PARAMETERS AND POLYPHENOL CONTENT IN RESPONSE TO DIFFERENT PLANT SPACING IN EDIBLE HIBISCUS PRODUCTION
Get PDFThe aim of the study was to verify the effect of plant spacing on the yield parameters and quality of edible hibiscus fruits, known as okra. The results were compared with other authors who studied the connections between plant spacing and other production parameters. Two varieties (\u27Baby bubba ́ and ́Clemson spineless ́) and different spacing effect (S1 = 0.6 x 0.45m; S2 = 0.5 x 0.45m; S3 = 0.6 x 0.3m; S4 = 0.5 x 0.3 m) on average fruit weight, yield per plant, yield per hectare and content of total polyphenols were tested in work. The average fruit weight of cultivar ́Baby bubba ́ variety was ranged from 25.7 g (S1) to 28.7 g (S2). The yield per plant was ranged from 308.2 g (S1) to 345.0 g (S2). The yield per hectare was showed by significantly different results; the highest okra yield was found in the variant of spacing S4 (21.1 t.ha-1) and the lowest yield was found in the spacing variant S1 (11.3 t.ha- 1). The content of total polyphenols in okra fruits was significantly highest in S1 spacing (16519.6 mg GAE.kg-1 DM), compared to other spacing variants. In ́Clemson spineless ́ okra cultivars, slightly different results were found. The average fruit weight of okra was ranged from 19.2 g (S4) to 25.8 g (S2). The yield per plant was ranged from 230.9 g (S4) to 309.3 g (S2). The effect of plant spacing in this cultivar was similar to results of yield in the cultivar ́Baby bubba ́. The yield per hectare was ranged from S1 (10.8 t.ha-1) to S4 variant (15.3 t.ha-1). The highest content of polyphenols was also found in the spacing S1 (17694.8 mg GAE.kg-1 DM). Obtained results showed on the significant effect of plant spacing and grown cultivar on the yield parameters and polyphenol content. Results can be usable for potential growers of okra in conditions of Slovak Republic, or Middle-Europe generally
LABOR FORCE IN 2 SOUTH-EAST REGION. COMPARATIVE ANALYSIS REGARDING THE LABOR FORCE FROM 2 SOUTH-EAST REGION AND BUCHAREST-ILFOV REGION
Get PDFEconomic growth in a region is seen as a broad, diverse, and complex process that depends on many key tools, such as small and medium-sized enterprises, job creation, research institutions and organizations. In this paper, we aim to highlight the main characteristics of the labor force in Region 2 South-East in 2021. Identifying the main elements specific to the labor force, we will make a monograph of the labor market in the region studied, but we will address in a comparative way of the indicators that describe the labor force between the studied Region and the Bucharest-Ilfov Region. In the process of analysis and interpreting data and information we used a computer application for spreadsheets. Our country is among the countries with the least active populations with employment contracts. The development process involves increasing the living standards of the inhabitants due to improved incomes
IMPACT OF BOARD AND TOP MANAGEMENT GENDER DIVERSITY ON COMPANY PERFORMANCE
Get PDFThe paper is focused on the impact of Board of Directors and Top Management Team gender diversity on the company performance. Variables related to Board and Top Management gender diversity and various company characteristics were used to evaluate their impact on the company performance measured as company yearly revenue per employee for fiscal year 2020. Used data set consists of data for 722 multinational enterprises from 39 countries all around the globe. The results of lineal regression confirmed that the company performance is influenced by Board and Top Management gender diversity, and by company ownership and the size of the company
ECONOMICS OF AGRICULTURAL PRODUCTION IN SLOVAKIA: DEVELOPMENT AND PERSPECTIVES
Get PDFThe agricultural sector is a branch of the national economy whose main task is to provide food for the population. At the same time, the needs of humanity are constantly increasing, which is linked both to population growth and to improvements in the quality of life. To solve these problems, it is necessary to rationalize the forms of combining factors of production and their qualitative and quantitative ratio in the production process in agriculture based on the measurement of production dependencies. Modern trends in the development of the agricultural sector in Slovakia appeared in the 90s of the 20th century. Between 1990 and 1999, Slovakia\u27s agriculture was transformed under new market conditions in order to achieve greater efficiency and productivity. During the economic crisis, unemployment increased, stocks of products decreased, the management structure changed and support from the state decreased, which led to the formation of a market-oriented agriculture. Following Slovakia\u27s accession to the EU, it assumed new obligations in the field of environmental legislation. Slovakia got the opportunity to use EU funds to increase the efficiency and productivity of agricultural production and improve the quality of life of the rural population. The main goal was to analyze the trends in the development of the agricultural economy in Slovakia, to identify existing problems and ways to solve them, to describe the prospects for improving agricultural production. One of the promising areas for the development of agriculture in Slovakia is the bioeconomy, which is able to solve some of the problems and introduce new and improved methods to improve the efficiency of agricultural production. The indicators of the development of agriculture in Slovakia over the past 20 years show a relatively stable development. The general dynamics reflects a decrease in the productivity and efficiency of agriculture, a decrease in labor productivity, and the insecurity of the domestic market with food. To do this, it is necessary to adhere to new CAP and RDP policy principles and introduce more effective incentive measures from the state and new ones to bring the productivity of agricultural labor and its efficiency to the average European level
ENTREPRENEURSHIP OF GENERATION Z READING IN FACULTY OF ECONOMIC ADMINISTRATIVE SCIENCES OF UNIVERSITIES, DEPARTMENTS OF BUSINESS, PUBLIC ADMINISTRATION AND ECONOMICS
Get PDFIn today\u27s world, there are many factors that affect the entrepreneurial ability of individuals and societies. In this sense, demographic, cultural and social factors that affect the entrepreneurial ability of an individual are considered to be effective. In terms of sustainable development, the development of entrepreneurship of young people is important in terms of production and creating added value. The aim of the study is to analyze the entrepreneurial ability of the generation Z students studying at the university. In this sense, it is aimed to analyze the entrepreneurial skills of generation Z students from Economics and Administrative Sciences, Business, Economics and Public Administration departments of state and foundation universities and take measures to complete their deficiencies. It was decided to study on this subject due to the predictions about the lack of entrepreneurial skills of generation Z students. In this study, the survey method was used as one of the quantitative data collection methods. Questions of the survey were delivered to the participants through online and face-to-face data collection applications. In this context, 282 surveys with a margin of error of 0.05 should be applied and 320 surveys were planned to be applied considering the margin of error. Scientific research and evaluation methods were used with the SPSS program for the evaluation of questionnaires