Emerging Science Journal

Purpose: Angiogenesis is essential for tumor growth or metastasis. Avastin is a monoclonal antibody that is used in treating angiogenesis. We labelled this monoclonal antibody with samarium153 and performed in vitro quality control tests as a first step in the production of a new radiopharmaceutical. Material and Methods: For a successful radiolabeling, we chose DOTA-NHS as the bifunctional chelating agent and optimized radiolabeling condition with modifications of the factors such as reaction time and molar ratio which are known to be very critical in radiolabeling. The efficiency and in vitro stability of antibody labelling were determined using thin layer chromatography. The integrity of the radiolabeled antibody was checked by SDS-PAGE. Biodistribution study of 153Sm-DOTA –avastin was carried out in BALB/c mice at 2, 24, 48 and 72 hours after injection. Immunoreactivity and toxicity of the complex were tested on colon cancer cell line by MTT. Results: The efficiency of antibody labelling was more than 99%. The in vitro stability of the labelled product in human serum after 120h was 78 ±2%. There was no fragmentation in the labelled antibody during SDS-PAGE protocol. The highest of %ID/g was observed in the blood, liver, lungs and spleen. The immunoreactivity of the complex was 89±1.4%. At a concentration of 1 nM, the complex killed 70±3% of SW480 cells. At 1.9 nM, 90±5% of the cells were killed. Discussion: The monoclonal antibody avastin against angiogenesis was effectively radiolabeled with 153Sm. The results showed that the new complex could be considered a promising tracer for noninvasive delineation of angiogenesis.

The paper maps quantum computing research on various publication and citation indicators, using data from Scopus database covering 10-year period 2007-16. Quantum computing research cumulated 4703 publications in 10 years, registered a slow 3.39% growth per annum, and averaged 14.30 citations per paper during the period. Top 10 countries dominate the field with 93.15% global publications share. The USA accounted for the highest 29.98% during the period. Australia tops in relative citation index (2.0). International collaboration has been a major driver of research in the subject; 14.10% to 62.64% of national level output of top 10 countries appeared as international collaborative publications. Computer Science is one of the most popular areas of research in quantum computing research. The study identifies top 30 most productive organizations and authors, top 20 journals reporting quantum computing research, and 124 highly cited papers with 100+ citations per paper.

The pandemic Covid-19 has been changing tourist behavior to visit a tourism destination. This study aims to investigate tourist’ visit intention after Covid-19 pandemic period in Indonesia by addressing the Covid-19 phenomenon, health consciousness and theory planned behavior framework. To answer hypotheses in this study, Confirmatory Factor Analysis-Structure Equation Model is used with quantitative approach. The research model is examined by SEM-PLS, using SmartPLS-3 software to analyze research framework. The results show that Covid-19 perception had not significantly impacted attitude, subjective norm, perceived behavioral control and intention. However, the perception of Covid-19 has a significant impact on non-pharmaceutical intervention, which in turn delivers a significant impact on attitude, subjective norm, perceived behavior control and visit intention. The hypothesis presumes that attitude, subjective norm, and perceived behavior control all have significant impact on intention to visit. In contrast, variable of health consciousness works less impact on intention to visit. This study makes significant contribution to the tourism literature by considering health issue and tourist visit behavior after Covid-19 period in Indonesia. Doi: 10.28991/esj-2021-SPER-15 Full Text: PDF

The COVID-19 pandemic brought CDTs to the forefront of business life. This study provides an important insight into a specific country's context, which has not been sufficiently investigated. This paper aims 1) to investigate how companies’ general characteristics impact the use of contactless digital technologies (CDTs) in Hungary; 2) to examine employees’ attitudes regarding the use of CDTs; and 3) to explore how firms have tried to enhance employees’ acceptance of CDTs. A computer-assisted data collection (CAPI) was carried out during the coronavirus (COVID-19) period. The online questionnaire was completed by employees of Hungarian companies. Descriptive statistics and relationship analyses (Cramer's V and Kendall's Tau) were used to analyse the collected data ( ). Results indicate that 1) the general characteristics of companies, such as their profile and size, have a significant impact on the use of CDTs; 2) the typical attitude of employees towards CDTs is rather positive; and 3) the acceptance of the use of CDTs can be supported by practical rather than theoretical solutions. The result can add value and stimulate new research related to the usage of CDTs, potentially serving as a useful benchmark for other countries. Doi: 10.28991/esj-2022-SPER-015 Full Text: PDF

COVID-19 pandemic lockdown measures reasonably limited the social contacts of people in many countries. It is crucial to understand the effect of such policies on people’s social ties and the possible need for evidence-based public policy amendments. Therefore, this study examines 1) the prevalence of loneliness in the population aged 15+ in Lithuania in late 2021 and 2) the self-rated effect of the COVID crisis on loneliness in population groups with different levels of loneliness. It also focuses on the socio-demographic characteristics of these population groups. Data from a representative cross-sectional quantitative survey (N = 1067), carried out in November–December 2021, was used. Based on the 6-item De Jong Gierveld Loneliness Scale, descriptive statistics analysis revealed the high prevalence (51% of a medium level of loneliness) in the Lithuanian population. One in three people (36%) declared low-level loneliness, and each seventh or eighth (13%) reported high-level loneliness. The feelings of respondents who reported a high level of loneliness were also less stable; they more often stated that their feelings of loneliness increased during the pandemic. These research findings make contributions to studies of loneliness within the context of sudden crises. They emphasise the importance of policymakers focusing on additional measures when preparing for future emergencies and providing special attention to residents who experience the highest levels of loneliness. Doi: 10.28991/ESJ-2023-SPER-020 Full Text: PDF

The study proposes a conceptual model of sustainable bank performance antecedents in the Covid-19 Pandemic Era. This study uses a qualitative perspective. Data gathering is done using depth interviews with the Indonesian Central Bank, the Authority of Financial Services, and the National Commercial Banks Association members. Using ethnography analysis from interviews, focus group discussions, and previous studies shows that many variables affect the performance. However, the exogenous variable on performance is without precisely placing fintech and regulations as an antecedent. The study results then constructed the fintech and regulations as intervening and moderating variables for the performance, whereas the other variables were as business driver variables. The study's improvement is that fintech and regulations are the main antecedents for the performance during the pandemic. Fintech is not only an entity outside the bank but also an innovation inside the bank. Moreover, the other improvement is that the bank is not only an institution of customer trust but also an institution with a full touch of technology. Consequently, banks must adopt fintech, and cooperating with fintech entities is a wise choice. The study then proposes a conceptual model of sustainable bank performance that connects business drivers, fintech, and regulations. Doi: 10.28991/ESJ-2022-06-04-09 Full Text: PDF

Covid-19 pandemic has compelled countries to conduct contact tracing vigorously in order to curb the highly infectious virus from further spread. In this context, Bluetooth Low Energy (BLE) has been broadly used, utilizing Received Signal Strength Indicator (RSSI) for Close Contact Identification (CCI). However, many of the available solutions are not able to adhere to the guidelines provided by Centers for Disease Control (CDC) and Prevention which are: (1) Distance requirement of within 6-feet (~2 meters) and (2) Minimum 15-minutes duration for CCI. In providing some closure to the gap, we proposed a novel approach of utilizing: (1) Low calibrated transmission power (Tx) and (2) Number of signal captures. Our proposed approach is to lowly calibrate Tx so that when distance is at 2 meters between users, number signal capture gets lower as the chipset’s smallest RSSI sensitivity value has been reached. In this paper, complete experimentation for Proof of Concept (POC) and Pilot test conducted are demonstrated. Results obtained shows that the accuracy for POC utilizing signal captures for 2 0.3 m distance is at: (1) 71.43% for 5 users and (2) 70.69% for 9 users. While so, accuracy for the Pilot test when considering CCI on individual case-basis is at 95% for 5 users. Doi: 10.28991/esj-2022-SPER-013 Full Text: PDF

Objectives: This study aimed to explore the six cultural dimensions of Geert Hofstede that affect perceptions of quality of life in 26 European countries during the COVID-19 pandemic (April 2020–March 2021): (1) Quality of life, (2) Democracy and trust, (3) Working during COVID-19, (4) Financial situation, (5) Support during COVID-19, and (6) Health care during COVID-19. Many studies are not conclusive on which dimensions of national culture affect the spread and death rate of COVID-19. The researchers, therefore, consider that studying the pandemic from the perception of quality can prevent its spread and contribute to the care and security of people affected by COVID-19. This study may be another way of providing information to those stakeholders. Method: To determine which aspects of culture affect the quality of life of Europeans during the COVID-19 pandemic, the researchers analyzed data through stepwise multiple regression analysis to predict the relationship between independent variables (cultural dimensions) and dependent variables (perceptions of the quality of life). Findings: It was found that during the COVID-19 pandemic, countries with higher power distance and higher uncertainty avoidance had a lower quality of life in several dimensions, mainly in Eastern European countries and Latin European countries (France, Italy, Portugal, and Spain). In the Nordic or Scandinavian countries with higher levels of indulgence, people were more satisfied with their quality of life in spite of the COVID-19 epidemic. Novelty/Improvement:The results may inform policy-makers and stakeholders on how national cultures have both positive (i.e., indulgent and long-term) and negative (high power distance and high uncertainty avoidance) effects on the quality of life of Europeans during the COVID-19 pandemic. There should be (1) short-term measures to provide equal economic measures and public health assistance to reduce anxiety (reduce high power distance and high uncertainty avoidance), (2) medium-term measures to promote education and training to prepare people for new modes of working in the future (decrease high uncertainty avoidance), and (3) long-term measures to cultivate cultures to save for the future and to be optimistic and happy, both mentally and physically (increase long term orientation and indulgence). Doi: 10.28991/esj-2022-SPER-02 Full Text: PDF

Globalization has opened the avenues for the world to come together and attain sustainable growth. Migrant workers are a lifeline for several countries' labour forces and productivity. However, in Thailand, the rights of these migrants are restricted due to the non-ratification of the International Convention on the Protection of the Rights of Migrant Workers and Family Members (ICRMW). This research explores and analyzes various factors essentially responsible for the ratification of ICRMW in Thailand. The methodology adopted is the mixed method. The collected data were analyzed based on a socio-legal approach, with qualitative and quantitative tools and techniques combined: the strength, weakness, opportunity, and threats (SWOT) technique was integrated into the analytic hierarchy process (AHP) (SWOT-AHP). The findings suggest that Thailand has not yet ratified the ICRMW conventions, including ILO C-87 and ILO C-98, thus depriving migrant workers of protection. They are not protected by national law and are not entitled to equal protection as nationals: for instance, foreign workers are forbidden from migrating to the established labour unions and enjoying medical benefits and salaries. All these must be consistent with the conventions, particularly the Labor Protection Act, B.E. 2541 (1998) and the Labor Relations Act B.E. 2518 (1998). The novelty of this research is the analysis of the domestic and international laws in the Thai context, which depicts the need for ratification of ICRMW to protect migrant workers and their families. The findings can pave the way for similar future research in other ASEAN member countries. Doi: 10.28991/esj-2022-SPER-014 Full Text: PDF

Using machine learning algorithms for the rapid diagnosis and detection of the COVID-19 pandemic and isolating the patients from crowded environments are very important to controlling the epidemic. This study aims to develop a point-of-care testing (POCT) system that can detect COVID-19 by detecting volatile organic compounds (VOCs) in a patient's exhaled breath using the Gradient Boosted Trees Learner Algorithm. 294 breath samples were collected from 142 patients at Istanbul Medipol Mega Hospital between December 2020 and March 2021. 84 cases out of 142 resulted in negatives, and 58 cases resulted in positives. All these breath samples have been converted into numeric values through five air sensors. 10% of the data have been used for the validation of the model, while 75% of the test data have been used for training an AI model to predict the coronavirus presence. 25% have been used for testing. The SMOTE oversampling method was used to increase the training set size and reduce the imbalance of negative and positive classes in training and test data. Different machine learning algorithms have also been tried to develop the e-nose model. The test results have suggested that the Gradient Boosting algorithm created the best model. The Gradient Boosting model provides 95% recall when predicting COVID-19 positive patients and 96% accuracy when predicting COVID-19 negative patients. Doi: 10.28991/ESJ-2023-SPER-08 Full Text: PDF

The literature on COVID-19 impacts overlooks the pandemic’ impact on informal traders who operate in undesignated public spaces. While studies on the impact of COVID-19 on informal traders exist, there remains little focus on how the socio-economic livelihood activities of informal traders in undesignated public spaces, such as parks, who rely on both domestic and international tourists as customers, have been impacted. This paper fills this gap by focusing on two case studies of urban public spaces in the city of Tshwane, South Africa. These spaces are Jubilee Square and Magnolia Dell Park. The study is predicated on the spatial triad framework which enables it to interrogate how the restriction on access and utilisation of public spaces during the COVID-19 lockdown impacted on the socio-economic activities of informal traders. It found that informal traders in these two parks were the most vulnerable category of traders during the COVID-19 lockdown and faced huge socio-economic and livelihood challenges. They lost their income sources and had their social networks disrupted. The article proposes social policy interventions in the governance of public spaces as part of an effort to save both lives and livelihoods in the face of a pandemic. Doi: 10.28991/ESJ-2023-SPER-07 Full Text: PDF

Objectives: Recently, due to special conditions that the global community is experiencing (Covid-19), there is growing interest in research in educational leadership, especially in higher education, which will create an environment embedded in a collaborative culture, open to improvements, testing, and often unexpected challenges. Among the different forms of educational leadership, transformational leadership is recognized as the most appropriate for application in higher education, as it focuses on the division of leadership among academics with different skills in order to manage in a collective way the range of leadership duties required in different contexts. Methods/Analysis: This view is also reflected in this research paper, which focused on the degree of three specific forms of leadership (transformational leadership, transactional leadership, and leadership to be avoided) by members of the Senate of the University of Peloponnese. Descriptive and inductive methods of statistical analyses were applied for the interpretation of results. Findings: Notably, the findings indicate that leadership outcome has a strong positive correlation with transformational leadership and negative correlation with passive-to avoid leadership, confirming that higher transformational leadership implies greater efficiency and satisfaction for employees. Novelty/Improvement:A high degree of passive leadership coexists with the corresponding negative degree of implementation of digital leadership. Doi: 10.28991/esj-2021-01252 Full Text: PDF

Vietnam's economy faces many difficulties and complicated developments. To create an environment with favorable conditions for sustainable development, it is necessary to have innovative business solutions that not only bring profits for businesses but also solve environmental and social problems. In addition, small and medium enterprises (SMEs) have made many positive contributions to economic restructuring, creating stable jobs for hundreds of thousands of employees and ensuring social security. Besides, SMEs in Vietnam have faced many difficulties and challenges during the COVID-19 pandemic. Thus, the papers' objectives explored critical factors affecting the sustainable development of SMEs in Vietnam. The authors applied two methods, such as qualitative and quantitative, with data obtained from 400 managers of small and medium enterprises and used structural equation modeling and SPSS 20.0, Amos software. The article's findings have the digital transformation factor's most substantial impact on sustainable development. The article's novelty is determined by five factors: market trends, state support policy, social responsibility, quality of human resources, and digital transformation. Finally, the authors recommended guidelines to help businesses be more cohesive in removing difficulties and solving issues related to credit relations to put capital into modern technology investment to ensure business effectiveness and sustainable development for SMEs. Doi: 10.28991/ESJ-2023-SPER-017 Full Text: PDF

This study analyses the current scenario with COVID-19 affecting the international and Thai space law, and its impacts and corresponding repercussions upon the Thai economy, ASEAN region and then at international level. The methodology adopted for this study is a mixed method with qualitative research tools collected from key informant interviews and focus group discussions. The data analysis involves the Strength, Weakness, Opportunity, and Threat (SWOT) analysis, which has been integrated with Hierarchical Thematic areas to provide the supporting model for wholesome recommendations through analyzing the findings from the research. The key respondents involved several government officials associated with Thai space agencies and departments, along with judges, lawyers, researchers, academicians, non-government organizations (NGO) officials, and law students. The findings provided the need for adoption of Treaty leading to the creation of a space organization which would be accountable towards setting up a legal framework for commencement of space mining operations. The international space tribunal is to be created under this international space organization to resolve any disputes arising out of space mining. The overall implications of this research would lead to the sharing of the benefits of space mining with both developed and developing countries to enhance sustainable development for all mankind. Doi: 10.28991/ESJ-2023-SPER-09 Full Text: PDF

During the COVID-19 pandemic, teleworking has proven to be an effective countermeasure to overcome the spread of this disease while enabling businesses to continue. However, little is known about the extent of their adjustment to daily life routine, interaction among self-control, assignments, family life matters, and coordination with colleagues. This study explores the impact of motivational factors on the performance of teleworkers. An exploratory study was conducted using an in-depth interview with 27 interviewees who work in Thailand and have more than a year of experience switching between being a teleworker and working on-site. The NVivo and SPSS software were performed to reveal deeper data insights and apply non-parametric tests in order to compare findings with various demographic profiles. The findings revealed that environment, time management, and reward are the strongest motivational factors, whereas labour intensity and job security present the weakest relationships with teleworkers’ performance. Numerous implications and strategies to enhance their performance for both organizations and workers are provided. Firms can support a well-prepared environment and manage the flexibility of working time to increase employees’ effectiveness. Moreover, the result-oriented approach can be one of the tools in evaluating their performance rather than attending to their full working time at home. Doi: 10.28991/esj-2022-SPER-016 Full Text: PDF

The primary factor that contributes to the transmission of COVID-19 infection is human mobility. Positive instances added on a daily basis have a substantial positive association with the pace of human mobility, and the reverse is true. Thus, having the ability to predict human mobility trend during a pandemic is critical for policymakers to help in decreasing the rate of transmission in the future. In this regard, one approach that is commonly used for time-series data prediction is to build an ensemble with the aim of getting the best performance. However, building an ensemble often causes the performance of the model to decrease, due to the increasing number of parameters that are not being optimized properly. Consequently, the purpose of this study is to develop and evaluate a deep learning ensemble model, which is optimized using a genetic algorithm (GA) that incorporates a convolutional neural network (CNN) and a long short-term memory (LSTM). A CNN is used to conduct feature extraction from mobility time-series data, while an LSTM is used to do mobility prediction. The parameters of both layers are adjusted using GA. As a result of the experiments conducted with data from the Google Community Mobility Reports in Indonesia that ranges from the beginning of February 2020 to the end of December 2020, the GA-Optimized Multivariate CNN-LSTM ensemble outperforms stand-alone CNN and LSTM models, as well as the non-optimized CNN-LSTM model, in terms of predicting human movement in the future. This may be useful in assisting policymakers in anticipating future human mobility trends. Doi: 10.28991/esj-2021-01300 Full Text: PDF

To protect their population during pandemic outbreak, countries apply several preventive restrictions and even shut down their economies to slow the spread of the coronavirus. Since food supply chains in developed countries are complicated and dependent on their external suppliers, these restrictions cause not only economic but also social tension. The limited access to raw materials, packaging material and labour force result in the increasing prices of food products, which forces the population to refuse from quality food products. In the European Union food supply chains, which are negatively affected by protectionist elements and COVID-19 restrictions, the room for manoeuvre of Latvia’s small open economy is limited. The current paper analyses the impact of COVID-19 crisis on global food industry, providing a deeper insight into the case study of Latvia meat supply chains’ experience in overcoming pandemic risks. The research outcomes lead to the conclusion that although COVID-19 impact during first breakout has not caused unexpected and serious consequences for the meat sector companies, the main internal and external risks are associated with further uncertainty and instability in the EU markets. Based on extensive analysis of meat sector specifics, the authors have summarized the recommendations for meat sector companies to better prepare for further potential pandemic situations. Doi: 10.28991/esj-2021-01257 Full Text: PDF

Advances in Information and Communications Technology (ICT) as well as the present challenges of COVID-19 have led to a new paradigm causing an absolute or partial transition from in-person classroom teaching-learning to online. There is little information available on research efforts that investigated the impact of an online learning approach on the academic performance of students in mechanical engineering-based courses. Therefore, the objective of this paper is the impact study of online learning mode as compared to in-person on academic performance of students in selected mechanical engineering courses in one of the Universities in South Pacific Islands prior-to-and-during COVID-19 Era. Data on grades obtained for 178 students that offered Fluid Mechanics, Thermodynamics, Heat Transfer, and Advanced Thermofluids (FTHA) courses were subjected to descriptive and non-parametric (Mann-Whitney and Kruskal-Wallis) statistical tests. Although descriptive analysis showed that online mode of instruction might influence a better academic performance in FTHA courses in comparison with in-person mode of instruction, the outcome of Mann-Whitney U and Kruskal-Wallis tests at specific p-values and corresponding z-values generally exhibited p-values higher than of 0.05, implying insignificant difference in performance between the two modes of learning investigated. Though the non-parametric statistical test results showed there was no significant difference in academic performance of students when online and in-person modes of learning were used, this, however, does not imply that a difference does not exist at all. Although the difference may be very trivial, descriptive analysis has shown that the online learning mode has at least exhibited better students’ academic performance when compared to in-person. It can be inferred from the foregoing that the online learning mode does not yield a negative response in respect of the performance of students who offered all four mechanical engineering courses. Based on the findings of this study, online is considered a reliable alternative to in-person or at least a suitable complement to in-person in the in-person-online hybrid mode during the ongoing COVID-19 era and other inevitable constraints in the future. Doi: 10.28991/esj-2022-SPER-017 Full Text: PDF

This study focuses on how the COVID-19 epidemic affects gambling motivation and behavior. This research also analyzes the behavioral intervention effects of the anti-epidemic measures on the COVID-19 epidemic and the relationship between the epidemic impact and gambling motivation and behavior. To investigate these connections, this research used Structural Equation Modeling to analyze 334 valid questionnaires collected during COVID-19 from gamblers from mainland China who visited the Macao Special Administrative Region. The results showed that the epidemic impact negatively affected gambling motivation and behavior, and gambling motivation partially mediated the relationship between epidemic impact and gambling behavior. Anti-epidemic measures positively moderated the epidemic’s impact on gambling motivation and behavior. This paper offers a theoretical contribution by proving the influence of the social environment on human motivational behavior, especially the effect of the COVID-19 crisis, and the support of government and enterprise anti-epidemic measures for behavior intervention theory. The practicality of this study consists of behavioral interventions from anti-epidemic efforts by regional government and industry to cope with the epidemic. These measures should influence the gamblers’ behavior intentions by considering the health and safety strategies that may reduce the impact of the COVID-19 epidemic on mainland Chinese gamblers. Doi: 10.28991/ESJ-2023-07-04-024 Full Text: PDF

Objectives: The current paper focuses on the impact of the unexpected event of the Covid-19 pandemic on the maritime industry. It searches the role adopted by key stakeholders of the shipping community with particular emphasis on the Ship Registries. Methods/Analysis: In order to conduct the research, there has been a thorough investigation concerning the initiatives taken by both governmental and private sector entities. Regulations and announcements issued to handle the Covid-19 pandemic are analysed and properly assessed. Findings: The response of the shipping sector, including the Ship Registries, was decisive and covered numerous aspects of maritime activity. Some of these actions taken can only be regarded as a temporary reply of the maritime industry to the threats imposed by the disease. At the same time, a significant part of these initiatives have a more permanent character and their acceptance by the maritime industry underlines their future potential. In this case, the appearance of the random event of the Covid-19 disease acted as a catalyst for developments in the shipping sector. Novelty/Improvement:This study is expected to contribute to the scientific orientation concerning the reaction towards the impact of future unexpected events with particular emphasis on the role of the Ship Registries. Doi: 10.28991/esj-2021-SPER-06 Full Text: PDF

The presented article deals with the description of the socialization of basic school pupils, i.e. pupils in younger and middle school age, who fulfill the compulsory school attendance in the form of individual education (homeschooling) in the context of the legislation of the Czech Republic. In the context of fulfilling the article aim, we formulated three research questions, which were evaluated using quantitative research in the form of a questionnaire survey. The research confirmed that parents of homeschoolers significantly support their children in participating in organized leisure activities and are actively involved in mediating their child's contact with other children. In the comparison of the examined groups there were no significant differences in how the children perceive their friends, what their favorite activities are or how much time they spend with them. The difference was more noticeable in the parental approach in education, when setting some rules. This article can outline areas that can be further explored in more detail and compared in context. Doi: 10.28991/esj-2021-SPER-12 Full Text: PDF

In Vietnam, the Covid-19 pandemic has taken place since the beginning of 2020, has seriously impacted businesses' production and business activities, and pushed the world economy into recession. Like other countries globally, Vietnam has been severely affected by this global pandemic. During the Covid-19 outbreak, small and medium enterprises (SMEs) that stopped production or went bankrupt increased. Besides, due to the deep integration into the global value chain now closed to the port, the findings explored that SMEs with a larger scale faced many difficulties. The number of enterprises having to shrink production also increased rapidly. Most businesses say the Covid-19 outbreak has negatively affected their production and trade. The primary official data is distributed directly to business leaders through detailed questionnaires to collect preliminary data and selected models by a simple random process. SMEs failed to reach customers, broke the supply chain, revenue plummeted, and laid off many workers, so far struggling. The study objectives found that more than 87% of businesses are affected by Covid-19. Therefore, the article novelty had several recommendations for enhancing the competitive capacity of small and medium enterprises in Vietnam after the Covid-19 pandemic. Doi: 10.28991/esj-2022-SPER-09 Full Text: PDF

Russia began to refocus its attention on the Asia-Pacific region in 1994, but the policy of pivoting toward Asia was implemented dramatically in the second decade of the 21st century. Adjustments made by Russia to its foreign policy and practical activities carried out by Russia in the region have impacted Russia-Vietnam relations generally and their economic ties in particular. Based on a qualitative approach and analysis of secondary data collected from previously conducted research works, this paper focuses on the following issues: (1) Adjustments made by Russia to its foreign policy towards Asia-Pacific over the first two decades of the 21st century; (2) Position of Vietnam in Russia’s foreign policy towards Asia–Pacific; and (3) Impacts of Russia’s new foreign policy on the economic ties between Russia and Vietnam over the first two decades of the 21st century. Based on the results of the analysis and evaluation, Russia's Asia-Pacific policy has been adjusted, particularly in the second decade of the 21stcentury, when the country turned its attention to Southeast Asia. Due to the importance of this region, Russia is implementing a comprehensive Asia policy and promoting Russia's interests in this region. The Russian Federation considers Vietnam an important partner in its "Look to the East" policy and plays a leading role because Vietnam is a country with an important geostrategic position to connect both land and sea between Northeast Asia and Southeast Asia. This is reflected in the Russian Federation's upgrading of its strategic partnership with Vietnam from 2001 to a comprehensive strategic partnership in 2012. The adjustment of the Asia-Pacific policy of the Russian Federation has positively affected the relationship between Vietnam and Russia in the economic fields (trade and investment). Doi: 10.28991/ESJ-2022-06-06-017 Full Text: PDF

The seismic excitation at the surface can be determined through Site Response Analyses (SRA) as to account for the specific soil properties of the site. However, the obtained results are largely affected by the model choice and setting, and by the depth of the considered soil layer. This paper proposes a refined 3D analytical approach, by the application of OPENSEES platform. A preliminary analysis has been performed to check the model adequacy as regards the mesh geometry and the boundary conditions. After the model setting, a SRA has been performed on various soil profiles, differing for the shear velocity and representing the different soil classes as proposed by the Eurocode 8 (EC8). Three levels of seismic hazard have been considered. The seismic input at the bedrock has been represented consequently, through as much ensembles of seven ground motions each, spectrum-compatible to the elastic spectra provided by EC8 for the soil-type A (bedrock). Special attention has been paid to the role of the considered soil depth on the evaluation of the surface seismic input. Different values of depth have been considered for each soil type and seismic intensity, in order to check its effect on the obtained results.

The aim of the paper is to evaluate the expectations of cohorts of workers from Generations X, Y, and Z with regards to their perceptions of what a "good workplace" is. Two research questions were formulated accordingly. Respondents representing workers from Generations X, Y, and Z, from Italy and Austria, were asked to consider and rate (on a 1-5 scale) eighteen criteria on work environment and managerial approach. Multi-sample testing was applied during processing with the ANOVA and Shapiro-Wilk and the Kruskal-Wallis test was subsequently used for multi-sample testing. The findings show that the most popular criterion for all three generational cohorts is "good work atmosphere", followed by "all employees are valued, treated, and rewarded fairly". Interestingly, generational differences were observed for "customer orientation", which was more important for Generation X, and "autonomous organization of work (time)", which was more important for Generations Y and Z. The most surprising result was the significance of corporate image, with less than 4% identifying this as an important issue across all three generations. These findings can help human resource managers create appropriate working environments and motivational tools that meet the real expectations of employees. Doi: 10.28991/ESJ-2023-07-03-013 Full Text: PDF

Minimum Redundancy Linear Arrays (MRLAs) and Uniform Linear Arrays (ULAs) investigation conducted with the possibility of using them in future 5G smart devices. MRLAs are designed to minimize the number of sensor pairs with the same spatially correlated delay. It eliminates selected antennas from the entire composite antenna array and preserves all possible antenna spacing. MRLAs have attractive features for linear sparse arrays, even if the built-in surface is deformed, it works without problems. To our knowledge, MRLAs have not been applied to smart devices so far. In this work, a 7-element ULAs and 4-element MRLAs (same aperture) were used for the simulation. The Half Power Beamwidth (HPBW) is 0.666 and the Null-to-Null Beamwidth ( ) is 1.385 in ψ-space. In comparison, the standard 4-element arrays are 1.429 and 3.1416, while the standard 7-element linear arrays are 0.801 and 1.795 respectively. Experimental results show that 4-element MLRAs have a narrower mean beam, much higher sidelobes and shallow nulls. Therefore, in terms of main lobe features, 4- elements MRLAs have an improvement over the standard 7-element ULAs. Doi: 10.28991/esj-2021-SP1-05 Full Text: PDF

In the recent few years, due to its significant deployment to meet global demand for smart cities, the Internet of Things (IoT) has gained a lot of attention. Environment energy harvesting devices, which use ambient energy to generate electricity, could be a viable option in near future for charging or powering stand-alone IoT sensors and electronic devices. The key advantages of such energy harvesting gadgets are that they are environmentally friendly, portable, wireless, cost-effective, and compact. It is significant to propos and fabricate an improved, high-quality, economical, and efficient energy harvesting systems to overcome power supply to tiny IoT devices at the remote locations. In this article, various types of mechanisms for harvesting renewable energies that can power sensor enabled IoT locally, as well as its associated wireless sensor networks (WSNs), are reviewed. These methods are discussed in terms of their advantages and applications, as well as their drawbacks and limitations. Furthermore, methodological performance analysis for the decade 2005 to 2020 is surveyed in order to identify the methods that delivered high output power for each device. Furthermore, the outstanding breakthrough performances of each of the aforementioned micro-power generators during this time period are emphasized. According to the research, thermoelectric modules can convert up to 2500×10^(-3) W/cm^2, thermo-photovoltaic 10.9%, piezoelectric 10,000 mW/cm^3 and microbial fuel cell 6.86 W/m^2 of energy. Doi: 10.28991/esj-2021-SP1-08 Full Text: PDF

The dependence of the absolute yield from energies for reaction (γ,γ’)m on the nucleus 77Se was approximated by fit dependences (lines). Due to the visually detected fracture of the reaction yield, the energy interval 5.75-8.0 MeV is conventionally divided into two parts. For the transition step as one experimental point, the left part was approximated to 6.6 MeV, and the right part - from 6.26 MeV. There approximations were eight for both intervals. Given the features of the calculation and the minimum values for χ2, the "best" two fits are approximation dependences in the neighborhood of the intersection point x0 for the left and right arrays of energies. The energy for the activation level (the intersection point for these functions) is Ea≈6.35 MeV. The scheme of electromagnetic γ- transitions for nucleus 77Se are constructed and analyzed. Possible transitions to the isomeric level from higher levels are indicated. Weiskopf model was used to estimate the values of the reduced probabilities of electric EJ- and magnetic MJ- transitions, the probabilities of transitions per unit time and half-life. The theoretical values of the half-lives T1/2 are compared with the experimental data. Prospects for further use of the obtained results for topical problems of nuclear physics are discussed.

Inverter systems that feed electrical power from photovoltaic (PV) system into the grid must convert the direct current of the PV array into the alternating current of the grid. In many applications, it is important for a converter to be lightweight, highly reliable, input/output isolated, flexible and operable in a boost mode. These features can be achieved by using a High-Frequency inverter which involves an isolated DC-DC stage and DC-AC section, which provides AC output. This paper proposes a new three phase topology, based on multi stage converter and PV system in order to use in medium and high power applications. The Perturb and Observe (P&O) method is used for maximum power point tracking (MPPT) control of PV array. The switching control signals for three-phase inverter are provided by hysteresis control method. Also, the comparison between the proposed topology and traditional structures has been conducted and finally the simulation researches are performed in a closed-loop control system by MATLAB/Simulink software to verify the operation of the proposed structure. The results represent better performance of the introduced system over traditional topologies.

The paper deals with the topic of corruption that has been understood as a global social problem since the 1990s. Its theoretical background is rooted in the theory of social constructivism. Social constructivism highlights the social strategy in which increased social discourse about a particular topic implies and reflects a growing interest of the society in the topic to arouse a robust awareness of the issue as a social problem. It analyses academic journals and conference paper proceedings that appear in a well-known database of academic journals and texts, namely in Web of Science. The research follows PRISMA methodology and it was conducted as an analysis of the terms and collocations that are connected to the issue of corruption with the aim to identify relevant research papers which have appeared in Web of Science since 1995. The idea behind this analysis was not only to identify the journal papers and papers published as conference proceedings but to compare the results geographically with well-known officially acknowledged state and government data dealing with the issue of corruption, and then to look for connections between these two areas, i.e. academic and governmental data. The results show significant differences between post-communist countries versus the so-called West regarding how they present information about corruption in their academic discourse. Despite the fact that the West supports the East in its fight with corruption economically, it is not reflected sufficiently and adequately in the relevant academic discourse. This paper suggests that societal resilience against corruption can dramatically be supported by enhanced academic discourse about the topic that is still not sufficient. Doi: 10.28991/esj-2021-01266 Full Text: PDF

In m-commerce, privacy and security are major concerns. Existing research has examined the privacy and relationship, security, and intention to use. However, the determinants of privacy and security in mobile commerce remain largely unexplored. A study based on UTAUT2 and trust examines the factors that influence mobile commerce privacy and security. By using the approach of hybrid SEM/ANN analysis, it is possible to detect non-linear and non-compensatory relationships. According to linear and compensatory models, the absence of one determinant can be compensated for by another. The decision-making process of consumers is actually quite complex, and non-compensatory or linear models tend to simplify it. The sample is collected by using a mobile commerce application in order to gather 890 datasets on mobile commerce consumers. Findings: (1) Two determinants of M-commerce acceptance and use had an explicit and significant positive effect. Security and individual are two of these factors. (2) Privacy concerns have a severe negative impact on M-commerce acceptance and use. (3) Trust is found to partially mediate the effect on behavioral intentions of Security Factors (SCF), Privacy Factors (PRF), and Individual Factors (INF) on m-commerce in Jordan (INTENTION). According to the integrated model, m-commerce offers 71% privacy, security, and trust. Doi: 10.28991/ESJ-2022-06-06-018 Full Text: PDF

This study is part of a government research project which aims to synthesise the current evidence on the factors affecting the intention of mobile application adoption called ‘Tripper Notifier Application’ (TNA) for the hospitality and tourism industrial sector in Thailand. The focus is on small and medium enterprises (SMEs), which emphasize restaurants, hotels, and attraction sites. The present article examines various factors influencing the intention to use such applications by employing the Unified Theory of Acceptance and Use of Technology 2 (UTAUT-2) as the theoretical underpinning of this research paradigm. Using 84 selected research papers in Scopus published between 2020 and 2022, A thematic analysis incorporating a grounded theory approach to systematically generate themes was conducted, and the findings found three main themes, including business transformation capabilities (BTC), digital transformation capabilities (DTC), and personal innovativeness (PI), as an extension of UTAUT-2 as mediator and moderator variables. To this end, the study fills the research gaps and extends the UTAUT-2 framework by including an initiative of twelve inside attributes-based lines, including performance expectancy, effort expectancy, social influence, facilitating conditions, hedonic motivation, price value, habit behavior, behavioral intention, and use behavior, together with three moderators: age, gender, and experience. Finally, the context dimensions of the UTAUT-2 extensions were mapped to highlight all the constructs of the TNA adoption framework for future research directions. The novel contribution of this study is to fill the gap with both theoretical and practical knowledge. On the theoretical level, this study constitutes constructs based on UTAUT-2 theory as a research-based setting to fill a gap in research. On the practical level, it provides insights and information about new capabilities that SME owners, managers, and practitioners should consider in order to differentiate their own capabilities. Doi: 10.28991/esj-2021-SP1-014 Full Text: PDF

Objectives: The goal of this paper is to address the issues that arose because of the exclusion of law offenders in the Greek Correctional Institutions from second chance education during the COVID-19 pandemic. During this period, the offenders were deprived of their right to equal access to second-chance education since the pandemics blocked mobility and close contact with teaching personnel. Methods/Analysis: In this paper, we propose a framework based on the Technology Acceptance Model (TAM) that will be deployed to evaluate the acceptance of the CILMS by the learners in Correctional Institutions. We describe a methodology and a set of hypotheses that can reveal the intention of learners to use the system based on several factors, such as trust, perception of privacy, perception of usefulness, and perception of self-efficacy. Findings: We suggest that eLearning and limited Internet access should be added to the list of fundamental human rights for CI detainees as well, in order to counteract their separation from physical society. Inmates are still individuals. In fact, they should be placed in solitary confinement as prescribed by the law. Novelty/Improvement:This viewpoint has been demonstrated with the development and evaluation of acceptance by inmates through the TAM technology acceptance methodology, as well as the proposal of a generic privacy-preserving Web information and services access model for CIs that can, at the same time, provide sufficient information access freedom while respecting the restrictions that should be imposed on such an access for CI inmates. Doi: 10.28991/ESJ-2022-SIED-017 Full Text: PDF

The growth of metropolises and the number of vehicles cruising within their boundaries creates a permanent problem of dissatisfaction with transport accessibility. This study aims to identify the difference between perceived (PA) and objective (OA) transport accessibility. For its implementation, it was necessary: to explore PA between different residential areas and travel modes, reveal the influence of the travel regime on the PA, compare the impact of social-demographic factors on the individuals' PA. The research methodology is based on a large cross-sectional study with 2,275 respondents. A quota sample was used for 12 administrative districts of the Moscow metropolis. The data was processed by IBM SPSS Statistics 20 statistical program to obtain descriptive statistics indicators. Correlation analysis of the respondent's answers to the four items for PA assessment was performed to assess the relationship between the results of the solutions. Next, a synthetic index of PA was calculated and analyzed differences using the integral index PA. The relationship significance was assessed using F-criterion-based one-way ANOVA. The novelty of our study is as follows: it contributes to previous research on the possibility of measuring perceived affordability in metropolitan areas and benchmarking OA and RA. Doi: 10.28991/esj-2021-01316 Full Text: PDF

Myelinated neurons are characterized by the presence of myelin, a multilaminated wrapping around the axons formed by specialized neuroglial cells. Myelin acts as an electrical insulator and therefore, in myelinated neurons, the action potentials do not propagate within the axons but happen only at the nodes of Ranvier which are gaps in the axonal myelination. Recent advancements in brain science have shown that the shapes, timings, and propagation speeds of these so-called saltatory action potentials are controlled by various biochemical interactions among neurons, glial cells and the extracellular space. Given the complexity of brain’s structure and processes, the work hypothesis made in this paper is that non-local effects are involved in the optimal propagation of action potentials. A non- local model of the action potentials propagation in myelinated neurons is proposed that involves spatial derivatives of fractional order. The effects of non- locality on the distribution of the membrane potential are investigated using numerical simulations.

This paper deals with the possibility of partial replacement of blast furnace slag with fly ash and fly ash after denitrification by SNCR method in alkali-activated materials based on granulated blast furnace slag. The aim of this paper is to verify the effect of fly ash on properties of alkali-activated materials based on blast furnace granulated slag. Frost resistance and resistance to aggressive environments, represented by demineralized water were tested. The reference mixture was based on blast furnace granulated slag activated by sodium water glass with silicate modulus of 2. Mixtures with an ash content of 10, 20, and 30% were then compared with the reference mixture. The influence of the denitrification process on fly ash and its use in mixed alkali activated materials was also compared. As a part of the experiment, alkali-activated pastes were also prepared. Infrared spectroscopy with Furier transformation was subsequently determined on these pastes. The reference mixture achieved the highest compressive strength in the experiment and the strength decreased with increasing amount of fly ash. In terms of flexural strength, the highest values were reached for mixtures with 10% slag replacement by fly ash. In the case of frost resistance, the significant increase of flexural strength, which was 50% for the reference mixture, is particularly interesting. For compressive strength, the frost resistance coefficient ranged from 0.95 to 1.00. In the case of resistance to aggressive environments, no differences were observed in the compressive strength, on the other hand, flexural strength decrease of up to 20% was detected for 10 and 20 percent replacement of slag with fly ash that did not undergo denitrification. Monitored properties did not show any negative effect of the denitrification process on fly ash properties. Infrared spectroscopy identified the main hydration product in the region of 945 cm-1which is a C-(A)-S-H gel and in combined mixtures with fly ash also N-A-S-H gel. Doi: 10.28991/esj-2020-01247 Full Text: PDF

The present paper focused on ad hoc networks with an emphasis on their dynamic nature. After an introduction to ad hoc networks, there are the AODV (Ad hoc On-demand Distance Vector) routing protocol with the node malicious behaviour and consequent damages to ad hoc networks. Then, trust is described as one of the solutions for identifying secure routes when there are malicious nodes in the network. Accordingly, the paper focuses on the proposed solutions that are based on the parameter trust and the prevention of the impact of malicious networks and vulnerable connections to identify a secure route. Then, an equation is presented to calculate trust using packet forwarding rate to select a secure route for sending data packets. The proposed model was implemented on OMNET++ to evaluate the network performance. The feature of the proposed method is better performance than of the methods TVAODV and AODV. Using the proposed method, packet delivery rate increases more significantly when malicious nodes increases than that of the basic method AODV and TVAODV. There is thus a lower packet dropping rate.

Application of new technologies is an obvious effects of today world. Internet as a newborn tool of contemporary technology world, plays an important role in change of people's life. Internet now is a necessary tool of modern era which makes it an inevitable component of everyday life. The present study aims to investigate level of sense of loneliness, identity styles and Internet Problematic Use among students. This is a descriptive survey study whose statistical population is all of the students of Technical - Engineering Faculties of Islamic Azad University in 1394-95 (2015-2016) in Tehran, using Multistage Cluster sampling method. 3 questionnaires, sense of loneliness, identity styles and internet addiction, have been selected for gathering data. Data analysis have been carried out by SPSS software. The results indicate that sense of loneliness is higher than two other variances which in turn end in internet addiction and identity disorders.

The research aim is to examine the possibilities of including the sodium humate (NaHum) additive derived from freshwater sapropel in feed to identify its effects on growth performance, promote haematopoiesis, and modulate the microbiota of the intestinal tract. The research was done under production conditions, complying with Latvian and European Union legislation on the keeping, feeding, and welfare of farm animals. The research had three replications, and for each of them, two groups of Holstein breeding heifers were established: control (3xn=7) and research (3xn=7). The duration of each replication was 9 days in the adaptation period and 105 days in the research period. The heifers of the research group received the NaHum solution additive with feed from the 1st to 35th day (stage 1) at an intake rate of 0.4 mL/kg of live weight, from the 36th to 70th day (stage 2) at an intake rate of 0.5 mL/kg of live weight, and from the 71st to 105th day (stage 3) at an intake rate of 0.6 mL/kg of live weight. The breeding heifers of the research group, receiving NaHum at an intake rate of 0.6 mL/kg of live weight, achieved a significantly higher live weight gain at stage 3 and an overall numerically higher live weight gain (by 4.8 kg) than the control group during the research period. Consequently, a significantly higher relative growth ratio (0.334) was found in the research group at stage 3, which was 0.028 higher than that in the control group. The Lactobacillus spp. count in faecal samples was steady at the end of the research; a significant difference was found between groups, with the average ranging between 6.95 (control group) and 8.49 log CFU/g (research (NaHum) group). The novelty of the research is that it was scientifically proven that feeding the NaHum additive derived from freshwater lake sapropel to the breeding Holstein heifers up to 5 months of age increased their feed intake and live weight gain, as well as activity and health. Doi: 10.28991/ESJ-2023-07-04-023 Full Text: PDF

This paper outlines on the preliminary outcomes of pilot project aimed at exploring the issue related to managing of maintenance activity in the Malaysian Small and Medium Enterprises (SMEs). SMEs have been accepted as vital components of domestic industry development in many countries. However, the literature portrays that many of Malaysian SMEs particularly the companies involved in manufacturing, fabrication and machining services are struggling to manage the maintenance of their manufacturing equipment. Dependable manufacturing equipment is important factor towards organizational profitability. Managing the maintenance activity of those manufacturing equipment nowadays, is becoming more challenging due to automation and computerization. Due to such issues, SMEs companies are under stiff pressure to minimize lost time for their survival. Thus, this study seeks to explore the related issues towards further improvements. Qualitative research methodology was adopted in the study. Data were collected at eight (8) SMEs located in three (3) different areas, namely southern, central and eastern region of peninsular Malaysia. Information was gathered from semi-structured interviews with SMEs management and observations focuses on different areas of maintenance management at the respective SMEs. The main concern is to validate the critical success factors (CSFs) in managing the maintenance activity at selected SMEs. This study discovered that nine (9) CSFs are having the most significant impact towards improving the maintenance management practice for SMEs. These include: understanding the MM philosophy; management commitment and leadership; maintenance strategy; maintenance planning; maintenance training; monitoring and assessment; appropriate number of maintenance staff; integration of tools, techniques and technology, and; record of maintenance data. All those CSFs construct are integrated in a simple yet self-explanatory MM Framework to convey the conceptual idea of MM implementation program to the management and technical people within SMEs. It is believed that the MM Framework developed would serve as an indicator of company’s MM focus level. Through the identification of the CSFs constructs, the SMEs can utilize the information to improve their approach in systematic MM program. The discovered CSFs are vital for all stakeholders that directly or indirectly involve in managing the maintenance activity in SMEs. Doi: 10.28991/esj-2021-01283 Full Text: PDF

Hospital is one of the most complex organization with highly intensive interaction between stakeholders (patients, nurses, doctors, staff, etc.). In the operation of a hospital, the use of Information technology has been proven to improve effectiveness and efficiency. However, in the majority of cases, the processes to achieve the Strategic Objectives through implementation of Information Technology are full of challenges. Based on the case study in Dharmais Cancer Hospital, there are many symptoms that are identified by this study and lead to 4 issues, namely: lack of ownership from Business users, lack of alignment between business strategy and IT strategy, lack of awareness to use IT as a tool for competitive advantage, and low quality of IT operation performances. In order to solve the issues and support the achievement of Strategic Business Objective through IT, an Enterprise Architecture approach can be used to develop baseline architecture, identify the target architecture, finding the gap, and use the gap as recommendation to solve those issues. The methodology chosen is TOGAF ADM, based on its focus on processes and its flexibility to combine artifacts and approaches that are most suitable for the case. This study develops 7 recommendations to Strengthen Business area of organization, 5 recommendations to Align IT plan with Business Strategy, 16 recommendations to Implement several IT solutions as Competitive Advantage for organization, and 8 recommendations to provide higher performances by enabling Service Management approach for IT Operation. This study also shows how TOGAF ADM can improve the awareness of the business users to the business itself. Doi: 10.28991/esj-2021-01278 Full Text: PDF

The present research aimed to establish a framework integrating the concept of technology readiness with variables that accomplished the blockchain adoption theory to identify the impact of blockchain adoption on supply chain transparency, blockchain transparency, and supply chain performance. The methodology used was quantitative with PLS-SEM as the analysis method. There were 295 validated datasets used. The procedure of data collection involved questionnaires. The key finding of the research confirmed the six proposed hypotheses. It was also confirmed that technology readiness, knowledge sharing, and trading needs were significant for the profitability of blockchain technology adoption in supply chain management. On the other hand, blockchain adoption played a significant role in supply chain transparency, blockchain transparency, and supply chain performance. The novelty of this research is in the integration of technology readiness into blockchain in the field of supply chain management. This research can be used to improve and analyze the success rate of blockchain adoption in supply chain management systems. The findings of this study contribute to several aspects, namely practical and academic implications, by providing more insights that correlate with blockchain integration into supply chain management systems. Doi: 10.28991/ESJ-2022-06-05-01 Full Text: PDF

In this research, immobilization of A. fumigatus α-amylase on chitin was studied with the main purpose to improve the characteristics of the enzyme. A series of experiments were carried out to study stability improvement, thermodynamic parameters, include ki, ΔGi, and t½, and reusability of the immobilized enzyme. The experimental results indicate that significant thermal stability was achieved, as indicates by the ability of the enzyme to retain its relative activity above 39% after 80 min of incubation at 60oC. Thermodynamic parameters, include ki, ΔGi, and t½, indicate that the immobilized enzyme is more rigid, stable, and less flexible in the water, resulting in increased stability up to 1.5 times compared to that of the native enzyme. Furthermore, the immobilized enzyme was able to retain over 46% of its initial activity after six consecutive applications for starch hydrolysis, confirming the potential of chitin for the production of immobilized enzymes on an industrial scale. Doi: 10.28991/ESJ-2023-07-01-06 Full Text: PDF

This article presents the research results that aim to develop promising mesh turbomachines equipped with jet control systems. The turbomachines operating in difficult conditions in oil and gas production are mainly considered. At the same time, some research results can be used in other production branches, including power engineering and transport. Three-dimensional models for computer simulation of net turbines and jet control systems were developed. Prototypes and micromodels were created to test the performance of mesh turbines and jet control systems using additive technologies. A methodological approach is proposed to create a classification of jet control systems considering their design and technological features. In the course of numerical experiments, the extreme conditions of fluid and gas outflow through a nozzle equipped with a velocity vector control system, in the control range of adjustment of the velocity vector deflection angle from + 90o to -90o within a geometric hemisphere, have been considered for the first time. It was also shown that when using a dual-channel nozzle, there are possibilities to adjust the velocity vector angle (thrust vector) in the range of + 180o to -180owithin the geometric sphere. Compared with the known variants, the control range of the velocity vector angle is increased by nine times. These calculated data are presented in addition to the previously published results of physical laboratory experiments. Preliminary results of numerical experiments show the possibility of creating a new theory in the field of mesh turbines and jet systems. Patents support the novelty of the developed technical solutions. Doi: 10.28991/esj-2021-01311 Full Text: PDF

Objectives: Working remotely comes with significant pros and cons with different demands for individuals or teams. E-working has been the object of much interest, but there has been little research on the statistical difference between its advantages and disadvantages. Research Question: Is there a significant statistical difference between them? Methods: The present research, however, goes one step further and identifies the statistical difference between them. Firstly, we evaluated the positive and negative aspects with a meta-analysis of 20 studies and, secondly, we used a non-parametric test, namely the Wilcoxon Rank Test, for further analysis across pros and cons. Findings: We found that e-working provides more positive than negative ones. A binomial test showed that most studies (more than 50%) mention flexibility, productivity and efficiency, satisfaction and WLB as benefits. Novelty/improvement:E-working is a triple win option. There are many advantages to working remotely, but this method of work does not suit everyone. Our results provide building blocks for a more complete theoretical and practical treatment of e-working for the future. But COVID-19, technology advancement and a connected global world show clearly that e-working will play a crucial role in the future of the workplace. Doi: 10.28991/esj-2021-SPER-02 Full Text: PDF

Maekuang reservoir is one of the water resources which provides water supply, livestock, and recreational in Chiangmai city, Thailand. The water quality and Microcystis aeruginosa are a severe problem in many reservoirs. M. aeruginosa is the most widespread toxic cyanobacteria in Thailand. Difficulty prediction for planning protects Maekuang reservoirs, the artificial Neural Network (ANN) model is a powerful tool that can be used to machine learning and prediction by observation data. ANN is able to learn from previous data and has been used to predict the value in the future. ANN consists of three layers as input, hidden, and output layer. Water quality data is collected biweekly at Maekuang reservoir (1999-2000). Input data for training, including nutrients (ammonium, nitrate, and phosphorus), Secchi depth, BOD, temperature, conductivity, pH, and output data for testing as Chlorophyll a and M. aeruginosa cells. The model was evaluated using four performances, namely; mean squared error (MSE), root mean square error (RMSE), sum of square error (SSE), and percentage error. It was found that the model prediction agreed with experimental data. C01-C08 scenarios focused on M. aeruginosa bloom prediction, and ANN tested for prediction of Chlorophyll a bloom shown on M01-M09 scenarios. The findings showed, this model has been validated for prediction of Chlorophyll a and shows strong agreement for nitrate, Log cell, and Chlorophyll a. Results indicate that the ANN can be predicted eutrophication indicators during the summer season, and ANN has efficient for providing the new data set and predict the behavior of M. aeruginosa bloom process.

The aim of this study is to systematize and improve the theoretical and methodological framework for implementing digital twin technology. The study focuses on digital twins in agriculture. This paper is designed to solve the scientific problem associated with the development of a methodological framework for the implementation of digital twins in the work of agricultural organizations. Using methods of analysis of socio-economic phenomena and processes on the basis of a set of scientific approaches, economic-statistical analysis, and others, the study considers the importance of digital twins of agricultural machinery and equipment, identifies trends in agriculture determined by digitalization, and suggests promising areas for digital twins of agricultural machinery and equipment. This paper also examines the theoretical basis for the implementation of digital twin technology in the agricultural sector of production. New research results complement the theoretical provisions on the essence of digital twin technology; develop the methodological provisions of digital twin technology, represented by the study of their significance, principles, and features of operation. The study may be seen as academically novel as it reveals the prerequisites for implementing digital technology in agriculture as well as clarifies and improves the theoretical and methodological provisions of the application of digital twin technology in various sectors of agriculture.

Business Intelligence (BI) is an essential technology in an increasingly competitive landscape since it helps make decisions more accurately. To achieve an effective BI implementation, the organization must formulate the right strategy to overcome its challenges. This research aimed to develop a framework to map barriers into strategies using qualitative and quantitative methods. The qualitative approach is driven by interviewing BI experts to validate the barriers and strategies previously obtained. Based on the interview, there are 19 barriers and 9 strategies that could be used. The quantitative approach compiles a priority list of the most significant barriers and the most effective strategies to overcome these barriers using fuzzy AHP TOPSIS, an MCDM method to eliminate inconsistencies during ranking. The results indicate that the lack of collaboration between the IT and BI departments, the BI implementation demands to be done quickly, and low data quality are the main barriers that hinder BI's success. This research also found that business people's involvement in a BI project is the best strategy to overcome the obstacles. The chances of a successful BI implementation will increase by having good cooperation between IT and business units within the company. Doi: 10.28991/ESJ-2022-06-02-010 Full Text: PDF

Ni- and Co-oxide materials have promising electrocatalytic properties towards the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR), and attract with low cost, availability, and environmental friendliness. The stability of these materials in alkaline media has made them the most studied candidates for practical applications such as a gas diffusion electrode (GDE) for rechargeable metal-air batteries. In this work, we propose a novel concept for a carbon-free gas GDE design. A mixture of catalyst (Co3O4, NiCo2O4) and polytetrafluoroethylene was hot pressed onto a stainless-steel mesh as the current collector. To enhance the electrical conductivity and, thus, increase ORR performances, up to 70 wt.% Ni powder was included. The GDEs produced in this way were examined in a half-cell configuration with a 6 M KOH electrolyte, stainless steel counter electrode, and hydrogen reference electrode at room temperature. Electrochemical tests were performed and coupled with microstructural observations to evaluate the properties of the present oxygen electrodes in terms of their bifunctionality and stability enhancement. The electrochemical behavior of the new types of gas-diffusion electrodes, Ni/Co3O4 and Ni/NiCo2O4, shows acceptable overpotentials for OER and ORR. Better mechanical and chemical stability of electrodes consisting of Ni/NiCo2O4 (70:30 wt.%) was registered. Doi: 10.28991/ESJ-2023-07-03-023 Full Text: PDF

One of the most important influences on battery safety, capacity, and cell ageing is heat generation and temperature inhomogeneity, which cause unbalanced ageing, resulting in cell performance decline. A well-developed temperature management module is required to avoid such undesirable actions. In this study, an air-cooled temperature management module was developed by coupling a unique heat sink of different pin-fin geometries/shapes to prismatic Li-ion cells and a 3D transient analysis was conducted to simulate the cooling performance of this heat sink under the effect of inlet airflow velocities and temperatures at a discharge rate of 2C for three cases. The results in the form of maximum temperature and temperature homogeneity inside the battery were derived and compared to the commonly used circular pin-fin heat sink. The overall result indicates that case 2, which consists of uniform height, shows better promise than others, taking into consideration the geometry employed. After 600 s and at a constant inlet air velocity of 0.412 m/s across a range of 20 oC to 35 oC, it was found that this heat sink performed better, providing an average of 1.87% and 1.93% improvement in temperature homogeneity and battery maximum temperature, respectively. Also, at a constant inlet air temperature of 27 oC across the range of inlet air velocity of 0.206 m/s to 0.824 m/s, this heat sink provides an average of 1.77% and 0.27% improvement in temperature homogeneity and battery maximum temperature, respectively. Doi: 10.28991/ESJ-2022-06-04-013 Full Text: PDF