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In this study, the extraction efficiency of rhenium ions in the form of perrhenate (ReO4?) from model aqueous solutions was investigated using a binary ion-exchange system based on KU-2-8 (strongly acidic cation-exchange resin) and AV-17-8 (strongly basic anion-exchange resin). The ion exchangers were separately weighed and combined in varying molar ratios (6:0, 5:1, 4:2, 3:3, 2:4, 1:5, and 0:6), and were immobilized within a chemically resistant polypropylene mesh bag to maintain phase separation while allowing s...

This study examines the morphological characteristics and shoreline dynamics of sandy beaches along the Burgas coast, one of the most diverse and human-impacted regions of the Bulgarian Black Sea. By integrating high-resolution Unmanned Aerial System (UAS) photogrammetry, GIS-based morphometric analysis, and historical shoreline data spanning the 1980s to 2025, the research provides a comprehensive assessment of coastal evolution over the past century. Five representative beaches, Sarafovo, Atanasovska Kosa, Burga...

Achieving efficient energy systems has become a challenge for researchers, as many engineering applications combine convective heat transfer in fluid saturated porous media, such as nuclear reactors, hydrogen production and storage, underground disposal of waste, food processing and storage, solar power collectors or geothermal systems. For this purpose, it is essential to calculate energy losses and identify methods that involve minimal costs. The paper presents a problem of free convection for a fluid flow throu...

Hybrid energy systems are a fundamental component of the future of energy resources. They are applicable across various sectors of industry and daily life. This study examines the integration of a photovoltaic system within a smart grid of charging stations for electric vehicles. The hybrid system consists of solar panels, inverters and an injection point. By simulating solar panels in simulator and analysis, the generated power over time is assessed based on solar irradiation data for a specific geographical loca...

The significant growth of the global population that has happened in the last years strains even more the present fragile balance between the produced and consumed resources, if the current rate of development is to be maintained without change the harmful and the negative effects caused by the global warming will only amplify.The increase of the water level, the desertification of fertile lands and the greenhouse gas effects are only a few of the problems we already need to resolve, because of this the transition...

The European Union (EU) Common Agricultural Policy (CAP) plays a crucial role in agricultural and economic development in the Member States. In the future, CAP support instruments must foster sustainable agriculture, with economic, social and environmental goals achieved through synergy. It would be increasingly important to assess the effectiveness of support payments in terms of their economic, social, and environmental dimensions. Accordingly, the present research aims to evaluate CAP support payments' soc...

The objective of the paper is to develop a methodology for arable land planning, taking into account the modern trends in agricultural machinery technologies and the contemporary environmental requirements for soil cultivation. It was found that design standards for arable land can be developed in the direction of: plot area up to 150 ha; working stroke over 1200 m; and aspect ratio up to 11. The study was based on two groups of spatial planning projects: two projects according to the existing design standards for...

The growing demand for refractory rare metals, such as niobium, necessitates the development of efficient extraction methods from alternative sources, including industrial waste from metallurgical plants enriched with niobium and zirconium. This study investigates the solvent extraction of niobium from a fluoride-sulfuric acid solution obtained by leaching rare-metal-containing waste from titanium-magnesium production. The efficiency of niobium recovery using a trialkyl phosphine oxide-based extractant (Cyanex 923...

The article considers the systematic errors of estimation of reserves and average contents of useful component in exploration of alluvial deposits of nesting, tape, etc. structures. The article identifies and evaluates the main components of systematic errors in the assessment of mineral content, useful and harmful components in alluvial deposits based on theoretical, experimental and generalized published works: insufficient density of the exploration network; error due to unrepresentative sample size. These erro...

Connected to the vision of bringing space closer to human beings, space tourism starts to become a new exciting free-time spending possibility allowing experiencing new unknown courageous activities linked to the possibility of viewing Earth from space. There are various types of space tourism such as orbital, suborbital and lunar ones. At the same time a big provocation for space tourists is to feel weightlessness and floating in space as the unique chance to contribute in a personal manner to advance science. As...

Urbanization and increasing traffic intensity contribute significantly to heavy metal pollution in urban environments, posing potential risks to public health and ecosystems. This study investigates the spatiotemporal variations of zinc concentrations in snow water within Jelgava, Latvia, from 2020 to 2024. A total of 59 sampling sites in Jelgava and an additional site in Mezciems were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) to determine zinc concentrations and identify potential pollu...

Specialization of production according to existing resources and the availability of sheep involves the use of new production systems, their readaptation to the demand for raw materials and the availability of feed resources. Depending on the existence of resources and the typology of sheep farms in the research area, production systems can be specialized for producing lamb, young sheep, and sheep reconditioned on pastures, and producing milk-meat in pastoral systems through the seasonal use of alpine pastures or ...

The aim of the study was to develop and validate analytical methods for the detection and quantification of arsenic species (As(III), DMA, MMA and As(V)) in different environmental matrices, including drinking water, surface water, groundwater, and sediments. The experimental tests were performed on a HPLC 1260 Infinity II coupled with an ICP-MS 7850 Agilent. For aqueous matrices, the method was validated within a working range of 10-50 microg/L using an Agilent G3154-65002 guard column and an Agilent G3154-65001 ...

The development, implementation, monitoring, evaluation and revision of the EU policies on agriculture, including environmental and the common agricultural policy, plant protection, sustainable use of fertilizers, pesticides and veterinary drugs, requires comprehensive and reliable statistical knowledge. The introduction of Regulation (EU) 2022/2379 on agricultural input and output statistics poses a challenge as it brings significant changes to the system in Latvia by not only broadening the range of inputs and i...

The transition to renewable energy sources is a key strategy for reducing carbon emissions and ensuring energy sustainability. This study explores the integration of photovoltaic (PV) systems for hydrogen production and storage in Constan?a County, Romania. The region benefits from high solar potential, making it an optimal location for implementing solar energy solutions. The proposed system converts solar energy into electricity through photovoltaic panels, which is then used to power an electrolyzer for hydroge...

In this paper, the authors analyze methods and technologies that contribute to the efficiency of an agricultural holding, in accordance with the principles of sustainable agriculture. The aim is to identify modern techniques (crop rotation, use of organic fertilizers, efficient irrigation, digitalization of agricultural processes, minimum sowing) that reduce the ecological footprint, as well as to compare traditional practices with modern methods of sustainable cultivation. The paper highlights solutions capable o...

A significant part of the built environment and historical architectural heritage in the EU consists of masonry structures. These old structures often undergo severe decay, reaching a critical state of deterioration and becoming highly susceptible to natural disasters, especially in earthquake-prone areas. Some of the structures hold architectural and historical value. Modernizing, repairing, and reusing the existing built environment, alongside efforts in extending its service lifespan, are among the most effecti...

This study examines the geomorphological and structural factors influencing the formation of coastal dunes along the Strandzha coastline of Bulgaria. Through the integration of GIS-based analyses, morphometric data, and geological profiles, the primary morphostructural units shaping coastal dynamics have been identified. These geological, morphostructural, and geomorphological conditions have provided the necessary prerequisites for dune formation. The research identifies a total of 17 dune systems along the Stran...

This study focuses on the structural and material optimization of a composite airbox for a Formula Student vehicle from the perspective of Life Cycle Assessment (LCA). Three evolutionary airbox generations are analyzed, each differing in geometry, number of parts, and material configuration, while maintaining the same primary manufacturing technology, in which the core structural material is a carbon fiber prepreg cured in an autoclave. The design optimization includes shell geometry simplification, integration of...

This study examines the travel behaviour of university students and academic staff at four Slovak universities, focusing on differences in transport mode choice and perceptions of mobility factors within the broader context of sustainable mobility in Europe. An online survey was conducted among university participants, assessing their primary travel modes and the perceived importance of five key factors travel cost, travel time, parking availability, environmental impact, and sharing using a five-point Likert scal...

The impact of abandoned mines on the water environment is a significant concern due to the long-lasting ecological and health effects associated with mining activities. Numerous scientific studies highlight that abandoned mines pose substantial threats to local water quality through the release of toxic substances and heavy metals into adjacent ecosystems. The zones of the 2 mines have been subject to various environmental and hydrological assessments, particularly concerning the effects of mining activities on wa...

As the offshore oil and gas industry faces mounting pressure to reduce its carbon footprint, Floating Production, Storage and Offloading (FPSO) units are emerging as critical platforms for implementing clean energy innovations. This paper explores the potential for integrating renewable energy sources such as offshore wind, solar photovoltaic, and wave energy with advanced energy storage technologies, including lithium-ion batteries and hydrogen-based systems, within FPSO operations. The hybridization of power gen...

The paper is devoted to the study of the combustion process in fibrous organic materials based on natural fibers. The paper presents the results of research focused on the study of the relationship between the microstructure of organic fibrous insulation materials, fiber properties and their resulting reaction to fire. This is a comprehensive approach to describing the reaction to fire beyond the scope of classification according to EN 13501-1. The basic test methods used to determine the reaction to fire are used...

This study investigates the flotation-based enrichment of black shale raw materials to selectively separate uranium and rare earth metals (REMs). The efficiency of various reagent systems-xanthogenate, kerosine, and paraffin with trichloroisocyanuric acid (TCCA)-was examined under different grinding fineness conditions. The initial material showed significant concentrations of uranium (0.188%) and REMs, with carbon content reaching up to 15%. The highest uranium removal (up to 98%) into mineral tailings was achiev...

Urtica dioica is a species of the Urticaceae family and the curative properties of this plant have been known since antiquity. Our study aimed to determine whether, in various concentrations and at different action times, the natural extract of Urtica dioica has positive, negative or neutral effects on mitotic cell division. For the proposed study, we used the standard Allium test and tested concentrations of 25%, 50% and 100% of the extract obtained, at action times of 6 and 24 hours. From the results obtained fo...

In order to predict water erosion processes on mountain slopes in the mountainous and foothill landscapes of Georgia, in May and September of 2024 a field scientific study was conducted in the ecosystems of Chiatura Municipality. As a result, five erosion-sensitive sites were selected, for which GPS coordinates and absolute heights above sea level were recorded and plotted on a digital map. Longitudinal and transverse profiles were made at the selected sites, and soil samples weighing up to 3 kg were collected. Te...

The processing of titanium-zirconium concentrates with high chromium content presents a significant challenge due to the inhibitory effect of chromium on industrial applications. This study investigates the composition of titanium-containing concentrate from the Obukhovskoye deposit using X-ray diffraction (XRD), X-ray fluorescence (XRF), and thermogravimetric analysis. The findings indicate that chromium is uniformly distributed in both magnetic and non-magnetic fractions, complicating its selective removal by co...

This paper demonstrates the importance of integrating modern technologies in the management of municipal infrastructures and highlights the significant advantages of using a municipal cadastral information system and an external database. With the help of GNSS technology and the total station, this precision requirement is met. The data from the measurements formed the basis for creating municipal cadastral plans that provide a detailed and accurate representation of the municipal networks. The methodology used in...

The maritime industry represents a significant contributor to global greenhouse gas emissions, primarily through the combustion of fossil fuels used by ship engines. As international regulations tighten and environmental awareness grows, reducing global greenhouse gas emissions from ships has become an important objective. This study explores the potential for emission reduction on passenger ships through the implementation of a hybrid propulsion system. The study methodology involves solving the following aspects...

During the process of adapting renewable energy and ensuring national energy security in the current geopolitical context, technological progress in the field of green energy has received increased attention. This has led to the development of updated policies on investment in onshore renewable energy (which uses wind and solar energy through wind turbines and photovoltaic parks) and offshore renewable energy (which uses tidal, wave, solar, and wind energy through floating photovoltaic parks and wind turbines that...

Green tea is one of the most widely consumed beverages worldwide. It is consumed on its own or in various combinations. Green tea is made from the leaves of the Camellia sinensis plant which originated in Asia. Green tea drinks have many health benefits for consumers due to the compounds present in the raw material - green tea. In order to benefit from all the properties of green tea - antioxidant activity, a wide range of vitamins, provitamins and polyphenolic compounds - the raw materials used are organically gr...

Tea made from the leaves of the Camellia sinensis tea plant is one of the most widely consumed beverages in the world, thanks to its sensory qualities and its content of active ingredients beneficial to health. Black tea contains antioxidants that neutralize oxygen free radicals. In these types of foods, the activity of enzymes such as oxidoreductases, which have NAD- (Nicotinamide adenine dinucleotide) or FMN- (Flavin mononucleotide) dependent coenzymes is very important in this biodynamics. [4], [5] Heme protein...

In recent years, several definitions of the bioeconomy have been developed, due to the fact that researchers have not been able to reach a common consensus. Through this study, we aim to develop this field and highlight the link between the bioeconomy and the four main resources that ensure the continuity of life on earth: air, water, soil and biodiversity. The main goal of the bioeconomy is to protect nature and biodiversity, by using resources that generate environmentally friendly products, but which also impro...

Cross-border Energy Communities are an essential tool for achieving the European energy transition, as they represent widespread, inter-territorial participation in energy production and sharing. European directives recognise and promote these configurations, both in the form of Renewable Energy Communities and Energy Communities of Citizens. However, actual implementation at national level remains non-homogeneous, creating obstacles to the full operation of the model. The Italian scenario is, in this sense, parad...

This paper focuses on densely clustered housing units located in residential complexes. A specific typology which is not present in European or Western architecture but has a place in Japan. Based on a qualitative research method with a descriptive approach, the current study presents the following hypothesis. This type of development brings the aspects of sustainability with an emphasis on high health and environmental standards, social inclusion, thrifty and efficient use of initial and operational resources whi...

Due to limited resources, development is associated with a process of transformation, including the performance of the transformation. In 2015, following the adoption of the Paris Agreement and the UN Sustainable Development Goals, the political agenda has shifted towards sustainable development for society, which includes environmental criteria. European Union Member States have strengthened the political agenda on sustainable development with the EU Green Deal initiative. Various development indexes could be emp...

The construction industry plays a critical role in global carbon emissions, contributing significantly to climate change. Embodied carbon, which encompasses all greenhouse gas (GHG) emissions associated with the extraction, production, transportation, and construction of materials, has become a critical focus in sustainable design. Building Information Modeling (BIM), with tools such as Autodesk Revit, Autodesk Forma, One Click LCA and Tully, among others, offers opportunities to streamline embodied carbon analysi...

The European Union (EU) climate objectives rely on sustainable agriculture. This research assesses greenhouse gas (GHG) emissions and key agricultural indicators in Latvia from 2020 to 2022. This research aims to assess the developmental trends of agricultural GHG emissions and farming indicators in Latvia to identify strategies or future investigations necessary to mitigate GHG emissions and enhance sustainability. In Latvia, agriculture accounted for 21-22% of total GHG emissions in carbon dioxide (CO2) equivale...

Agriculture plays a crucial role in the global carbon cycle, as it serves as a source of one of the greenhouse gases. Therefore, a data-based understanding of how to mitigate its impact on the environment and climate change is needed. The research aim is to evaluate the dynamics of the agrifood system in the European Union (EU) Member States from 2013 to 2022, with a primary focus on carbon dioxide (CO2) emissions, livestock population density, and agricultural land use. The results indicate that Germany, France, ...

Abandoned railway lines can be used as hiking trails for tourism development and as coherent eco-logical routes for many species of flora and fauna, such as plants, insects, and birds. The study's objective was to design a strategic plan for using unused railway lines that will increase or maintain the biodiversity in the Prefecture of Peloponnese in southern Greece. The SWOT-AHP-TOWS method analysis was used. The criteria of the SWOT (Strengths, Weaknesses, Opportunities, and Threats) method were recorded based o...

The design of urban drainage systems in the European Union generally follows the requirements of the EN 752 standard. Nevertheless, it uses a classical approach that aims only to convey stormwater runoff away from the settlement boundaries, thus preventing local problems. On the other hand, global tendencies are oriented towards a more sustainable approach for climate-adaptive metropolitan infrastructure. To address problems like urban expansion, expected future heavy rainfall events, sewer overloading, flooding, ...

We live in a world where, globally, the urban population represents 50% of the Earth's inhabitants, and in 2035, it is expected to represent 75%. In Romania, in 2024, 55.81% of the total population lives in urban areas and the difference in rural areas. In the paper, we set out to create an "x-ray" of the commitments that our country has assumed within the 2030 Agenda for Sustainable Development - Goal 11. Romania must find solutions for the sustainable development of communities, based on environmental education,...

Integrating sustainable development and circular economy principles into higher education curricula is critical for preparing future professionals to address complex global challenges. This study examines both the theoretical underpinnings and empirical evidence supporting the inclusion of these themes in academic programs in Latvia, emphasizing their role in fostering the competencies required for sustainable transformation. Using a mixed-methods approach, the research combines qualitative content analysis of cur...

Tourism is a key driver of economic growth and regional development, particularly in emerging destinations that capitalize on natural and cultural resources. This study explores the role of European-funded sustainable projects in enhancing tourism infrastructure, services, and environmental policies in the Western Region of Romania. [1] By analyzing various initiatives supported through EU funding (FEADR, EURI), the research identifies best practices and challenges in implementing sustainable tourism strategies. T...

This study addresses the limitations of conventional incentive systems in encouraging sustainable behaviors -- such as donations, ethical consumption, and CO2 reduction -- by highlighting their lack of transparency, long-term viability, and respect for privacy. To overcome these issues, we propose a decentralized reward framework built upon a blockchain-based Self-Sovereign Information Environment (SSIE). Verified actions are recorded through NFTs and smart contracts, ensuring immutable traceability without disclo...

This paper explores the rural-urban divide in the context of sustainable territorial development in Latvia. By employing a combination of statistical analysis, standardisation, and factor analysis based on 14 development indicators, the research identifies key differences between rural and urban areas. The results reveal that economic activity is notably higher in territories closer to the capital, Riga, although not all urban areas demonstrate superior performance. Simultaneously, urban territories concentrate mo...

Urban development and the construction industry have experienced in the last century massive development worldwide, and in Romania the last two decades have been marked by a considerable advance of construction projects growth. But sustainable urban development must be regulated by norms and standardization systems that lead to harmonious progress. In 1990, the first certification system for building sustainability, BREEAM, appeared in Great Britain and it is applied on a large scale mainly in Europe. The second c...

In this paper, we present some practical considerations regarding the design of power voltage stabilizer equipment. Nowadays, technologies for raising and/or lowering the voltage to a level required by the power line or a consumer are increasingly used (in wind or solar power generation systems, or in energy conversion systems with a direct current intermediate circuit). Our study refers to a conversion solution consisting of two converter stages. The first stage consists of two boost converters operating in antip...

We present herein a thoroughly study regarding the synthesis, structure and biological activity of some hybrid diazine - polyphenols derivatives. The synthesis was performed under conventional thermal heating and microwave irradiation, by using a straight and efficient method: a N-alkylation reaction of diazine (pyridazine or phthalazine) with reactive halogenated derivatives. The structure of the hybrids was proven by elemental and spectral analysis. Under MW irradiation, the N-alkylation reaction of diazine have...

Mannitol is an important raw material in the production of resins, lubricants, coatings, surfactants, explosives, cosmetics and drugs. One of the promising ways to obtain it is the catalytic conversion of inulin, a natural polyfructosan found in large quantities in some agricultural crops. In this study a Ru-containing magnetic catalyst was proposed for the process of hydrolytic hydrogenation of inulin to mannitol. Under optimal reaction conditions a high mannitol selectivity of 44.3 % was obtained 100 % conversio...