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Impacts of biocover composition on greenhouse gas emission Full text
2023
Siltumens, Kristaps | Grinfelde, Inga | Burlakovs, Juris | Liepa, Sindija | Grinberga, Linda
It is generally estimated that gas, which generates more than half of the greenhouse gas (GHG) emission from waste industries in landfills, is seen as a serious environmental problem worldwide. It is therefore essential to promote management methods to reduce GHG emissions from landfills as well as other sources. One way of achieving this is the usage of different types of biocover applied to them. The aim of this study is to clarify the impact of the biocover created on GHG emissions. An experiment was conducted in laboratory conditions that studied the effectiveness of biocover developed in the laboratory. Three experimental columns with a diameter of 160 mm and a height of 1500 mm were created. Active compost saturated with water at a thickness of 500 mm was used as a source of methane, a permeable layer of sand at a thickness of 300 mm was further formed and finally covered with biocover. Biocover represented 60% of fine-fraction waste, 20% of soil and 20% of compost. The experiment was launched on June 6, 2022, and the first measurements were made two weeks later. All measurements were performed with the CRDS gas measurement device Picarro G2508 (Picarro Inc., USA California). All data analysis was carried out using Descriptive statistics methods. The largest reduction in emissions is projected directly for methane emissions, as biocover technology is appropriate to reduce methane emissions. Other GHG emissions are also expected to be reduced. NH3 emission measurements were also carried out to investigate the impact of the biocover on it. This experiment shows that the biocover created is effective and can be composed of material that has already been served. The experiment is intended to continue to obtain long-term data on the development of biotransformation and to develop more promising approaches in the future to reduce GHG emissions from landfills.
Show more [+] Less [-]Perspective moving towards the implementation of circular economy in the wastewater sector: The case study of Latvia Full text
2023
Salmiņa, Aiga | Ozola-Davidane, Ruta | Fonteina-Kazeka, Maija | Konstantinova, Elina
The transformation from a linear to a circular economy model is a political priority of the European Union to develop sustainable and more efficient raw materials and waste management. The wastewater sector is an important element in the circular economy with a great potential for resource recovery such as phosphorus recovery from waste streams. With this in view, the present study’s aim was to analyse data on municipal wastewater treatment plants (>2,000 p.e.) in Latvia and the present situation with newly developed circularity indicators on waste reduction, pollutants removal, resource recovery and water reuse; thus, enabling evaluation of the level of transformation towards circularity in Latvia’s wastewater treatment plants and their future perspectives. The results showed that the wastewater sector in the country complies with legal obligations, but on the other hand, only a few solutions are practised in compliance with the principles of circular economy, i.e., reduction of wastewater discharge and increasing sewage sludge utilization as fertilizer in agriculture.
Show more [+] Less [-]Oil spills detection by means of infrared images and water quality data using machine learning Full text
2023
Zavtkevics, Vladislavs | Gorelikovs, Dmitrijs
The paper presents the results of the research on oil spill detection using machine learning methods such as Support Vector Machine (SVM) for classification of infrared images and Logistic regression for water quality parameters. This paper focuses on real time detection of oil spills using infrared images and water quality data obtained by RPA equipped with multi-sensor payload. The developed Naïve Bayes (NB), SVM and Logistic regression classification models for prediction of oil spill have been successfully tested in real experiment conditions. All developed classification models were tuned using grid search method and main tuning parameters to determine the optimal parameters. The proposed complex algorithm for identification of oil spills using infrared images and water quality parameters is evaluated by experiments in real environment conditions. The proposed algorithm is based on the binary SVM and NB classification of infrared images and the classification of water quality parameters using the machine learning method logistic regression allows to rapidly and with high accuracy identify any oil pollution of water. Proposed complex algorithm achieves higher accuracy and efficiency; moreover, the developed machine learning models will further reduce the probability of human error and save man-hours of work.
Show more [+] Less [-]Career development for enhancing employability of students as prospective specialists in the university educational environment Full text
2023
Troshkova, Marina
Universities play an important role in providing a wide range of services and connecting all stakeholders, such as employers, alumni, and other community members to prepare students for future employment, establish networking with labour market representatives, assist them in integrating into the labour market, and develop students’ as potential specialists’ employability skills, thereby fostering their career development in the university educational environment. The aim of this study is to analyse the career related theories and propose a career development model for economics and business-focused universities. The following research methods were used: desk study, analysis and evaluation of scientific literature (theoretical research method); reflection of personal experience (empirical research method). The theoretical research emphasised modern career-related theories and resulted in a proposal for a career development model for a university. A mandatory course that formally prepares students as prospective specialists for employment and internship, exposure to the labour market via internship, networking events, and mental support provided by qualified psychologists, university teachers as part of an academic advising programme and alumni organized in the form of an alumni mentorship programme, are the main pillars of the proposed career development model.
Show more [+] Less [-]Digitization of higher education in Ukraine: Organizational and applied aspects Full text
2023
Zamkova, Iryna | Dubinina, Maryna | Syrtseva, Svitlana | Cheban, Yuliia | Luhova, Olha | Kuchmiiova, Tetiana
Today in Ukraine, a digital transformation of the educational system of higher education is taking place at a rapid pace, in which information and communication technologies are not becoming an additional ʻload’ in learning, but an integral part of a comprehensive educational process, which increases its efficiency. At the same time, there are a number of challenges, including such specific ones as unprovoked military aggression, which complicates the process of entry of higher education in Ukraine into the global educational digital environment. To assess the significance of the digitalization of the educational system of higher education in Ukraine in specific conditions, to analyse the attitude of the teaching staff and students to online education, to establish technical means of participation in the educational process, to determine the advantages and disadvantages of distance learning through the prism of the experience of teaching staff and students, we used three main methods: the survey method, the method of analysis and synthesis, the graphical method. As a result of the study, the authors revealed the general concept of digitalization and its educational dimension; identified the main challenges faced by higher education institutions in the digital environment; determined the impact and scale of military aggression by the Russian Federation on the activities of Ukrainian universities; established the features of training in the digital environment by institutions of the higher education of Ukraine.
Show more [+] Less [-]Comparative study on the impact of COVID-19 on emotional well-being in the workplace Full text
2023
Vintere, Anna | Bartusevičienė, Inga | Aruvee, Eve | Rimkuviene, Daiva
Individuals’ emotional well-being is determined by several factors, including the ability to cope with daily stress and the ability to cope with various daily challenges. Ability of the management to provide favourable psychoemotional and psychosocial conditions within their team is particularly important. However, managers do not always have the knowledge and skills to lead their teams. For the development of the methodology, a study of the scientific literature on topical issue like healthy workplace was performed. The empirical part of the study is based on the results of the survey conducted Lithuania, Latvia, Estonia and Sweden within the Nordplus project ‘Dealing with anxiety during a pandemic to enhance adult well-being’ on the impact of COVID-19, as well as the training that would be necessary for the managers of companies or organizations to promote emotional wellbeing in the workplace. The comparative study was conducted from the perspective of both employees and managers. The results show that the impact of the COVID-19 pandemic on workplace and the well-being of employees was not strong for the respondents, depending mainly on the job position, the size of the organization and country. Managers and employees consider various psychological trainings essential.
Show more [+] Less [-]Hyperspectral imaging for early detection of foliar fungal diseases on small grain cereals: A minireview Full text
2023
Fiļipovics, Maksims
Globally crop pathogens and pests cause significant yield and quality losses in agriculture production systems. Foliar fungal diseases of small grain cereals are economically among the most important diseases worldwide and in the Baltics. Finding an effective, reliable, and easily accessible method for plant disease diagnosis still presents a challenge. Currently used methods include visual examination of the affected plant, morphological characterization of isolated pathogens and different molecular, and serological methods. All of these methods have important limitations, especially for large-area applications. Hyperspectral imaging is a promising technique to assess fungal diseases of plants, as it is a non-invasive, indirect detection method, where the plant’s responses to the biotic stress are identified as an indicator of the disease. Hyperspectral measurements can reveal a relationship between the spectral reflectance properties of plants and their structural characteristics, pigment concentrations, water level, etc., which are considerably influenced by biotic plant stress. Despite the high accuracy of the information obtained from hyperspectral detectors, the interpretation is still problematic, as it is influenced by various circumstances: noise level, lighting conditions, abiotic stress level, a complex interaction of the genotype and the environment, etc. The application of hyperspectral imaging in everyday farming practice will potentially allow farmers to obtain timely and precise information about the development of diseases and affected areas. This review provides an introduction into issues of hyperspectral imaging and data analysis and explores the published reports of worldwide research on the use of hyperspectral analysis in the detection of foliar fungal diseases of small-grain cereals.
Show more [+] Less [-]Carbon stock of deciduous forests on organic soils in Latvia Full text
2023
Bičkovskis, Kārlis | Samariks, Valters | Liepiņš, Jānis | Šņepsts, Guntars
Forests play a significant role in the mitigation of climate change through carbon storage and sequestration. However, a forest’s capacity to absorb carbon is influenced by a number of factors, such as soil characteristics, the selection of tree species, and the application of silvicultural practices. A study in Latvia was conducted to evaluate the carbon stock and sequestration potential of birch, common aspen, black alder and grey alder growing on periodically waterlogged and drained organic soils. Empirical data of forest resources were obtained from the National Forest Inventory (NFI) from 2016 to 2020. The findings indicate that black alder may thrive in both soil types, as it showed the best increase in carbon stock in periodically waterlogged soils, reaching a maximum of 129 t C haE−1 at the age of 61–70 years. Greater carbon sequestration in tree biomass occurs on drained soils compared to periodically waterlogged. Birch, aspen, and black alder stands may store between 106 and 119 t C haE−1 at age of 61 and 70 years, which is similar to grey alder stands at ages of 31–40 (114 ± 0.73 t C haE−1). Therefore, a short rotation for grey alder growing on drained organic soils could maximize carbon accumulation and add substitution value. These results suggest that different types of deciduous trees have varying capacities for carbon storage and sequestration, and that it’s important to consider site-specific factors, rotation age and silvicultural practices when aiming to maximize carbon sequestration in tree biomass.
Show more [+] Less [-]A review: Application of freeze-drying in meat processing Full text
2023
Loskota, Evelina | Gramatina, Ilze | Kince, Tatjana
Meat products play an important role in the human diet. They are one of the main sources of proteins, trace elements, structural components, as well as vitamins that stimulate human growth and physical activity. Raw meat refers to perishable food. There are many methods of preserving the quality and shelf-life of meat products, however, in recent years, freeze-drying is becoming more and more popular, and it combines two technological steps — freezing and vacuum drying. During the process, the product undergoes dehydration by removing water to a humidity level of 2–5%. The principle of the process involves transforming the product from a frozen phase to a gaseous phase, bypassing the liquid phase. The purpose of the article is to study the possibility and relevance of the freeze-drying process in the meat industry and to examine its advantages and disadvantages, as well as the probability of growth. During this research it was revealed that in the use of freeze-drying in the meat industry for certain purposes, it is still necessary to study and adjust in order to introduce it into a particular production. However, with regard to large enterprises where various production problems often arise this technology would not only help solve these problems, but also increase the range of innovative products and expand sales markets.
Show more [+] Less [-]Carotenoid extract and oil from pumpkin (Cucurbitta spp.) by-products for facial creams with high antioxidant activity Full text
2023
Konrade, Daiga
Nowadays, different sun protective creams are available in the market, but most of them contain harmful synthetic chemicals and minerals which can induce skin allergies and premature ageing. Usage of sunscreens and photoprotectors of natural origin and natural antioxidants can reduce skin damage caused by excessive sun exposure. The effectiveness of the use of β-carotene — vitamin’s A precursor against excessive irradiation caused by oxidative stress cell damages has been proven of its very good antioxidative properties and leading to sooner regeneration of the skin after several environmental damages. Carotenoids and high value oil can be extracted from pumpkin (Cucurbitta spp.) by-products — peel and seeds with SC CO2. The objective of this study was to incorporate pumpkin seed oil (PSO) and carotenoid extract (CE) from pumpkin by-products in to facial creams for UV protection. Two types of creams with PSO and CE were prepared emulsion o/w and w/o. A cream without extracts and natural ingredients was used as control sample. The sun protection factor values in vitro (SPF = 0.92 to 1.18), total content of carotenoids (TCC = 1.08–17.95 µg mLE−1), β-carotene content (0.64–0.72 µg mLE−1), total phenolic content (TPC = 62.64–95.82 mg GAE gE−1), antiradical scavenging activity (11.26–43.66 %) and rheological behaviour of facial creams were determined. Although creams with CE and PSO show comparatively low SPF values, ß-carotene and phenolic compounds found in samples demonstrated very high antioxidant abilities valuable for skin protection.
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