A Scenario-Based Electro-Physical Assessment of Urban Surface Heat Transfer and Electrical Cooling Demand in Smart Urban Environments

/0 Comments/in /by

Urban overheating is an electro-physical problem because surface heat accumulation changes outdoor temperature conditions and increases the electrical energy required for cooling. This study develops a scenario-based electro-physical assessment model for analysing the relationship between urban surface heat transfer, surface material properties, green infrastructure and electrical cooling demand. The model links physical parameters such as albedo, emissivity, thermal mass, vegetation coverage and urban–rural temperature difference with engineering indicators such as cooling energy demand, energy-efficiency improvement and CO₂ emissions related to electricity use. The case-study application uses Sofia Municipality as a spatial reference environment. Real spatial and land-use indicators are combined with scenario-based calculations in order to compare a baseline urban condition with an optimized scenario. The results are interpreted as early-stage engineering estimates rather than direct measurements of Urban Heat Island reduction or electricity consumption. The contribution of the paper is an integrated framework that connects heat-transfer processes with electrical energy performance in smart urban environments.

Tamarind Juice Assisted Benign Synthesis Of 2,3-Dihydro-1h-Perimidine Derivatives

/0 Comments/in /by

A green and efficient way to make 2,3-dihydro-1H-perimidine derivatives is through a one pot reaction of 1,8-diaminonaphthalene with different aromatic aldehydes using tamarind (Tamarindus indica L.) juice. The reactions were carried out in mild conditions, giving us the desired products in good or excellent yields with short reaction times. Tamarind juice was inexpensive, and easily available, and it was a metal-free and eco-friendly catalyst. The protocol is easy to follow, easy to separate products, low amount of catalyst, and does not include hazardous chemicals and chromatographic purification. This green way shows that tamarind juice is a good green catalyst for biologically important perimidine derivatives.

From Poetry to Opera: Pushkin And Tchaikovsky’s Eugene Onegin in A Holistic Accordance

/0 Comments/in /by

The present article examines Tchaikovsky’s Eugene Onegin to demonstrate how a holistic approach can deepen the performance of opera; the approach integrates the composer’s dramaturgical strategies, the literary source, and critical scholarship into a unified interpretive framework. The discussion focuses on Onegin’s rejection aria and establishes that Belinsky’s characterisation of Onegin as an “involuntary egoist” reshapes the performer’s vocal and dramatic choices. By tracking how contextual understanding directly informs decisions of vocal colour, articulation, and phrasing, the article illustrates the practical necessity of a holistic approach in which interpretation and technical execution are inseparable.

Motor Vehicle Growth in Guyana (2000–2025): Statistical Trends, Forecasting, And Infrastructure Implications

/0 Comments/in /by

Motor vehicle registrations are a key indicator of transport demand, economic development, and infrastructure pressure. This study examines long-term trends in motor vehicle registrations in Guyana from 2000 to 2025 and generates forecasts for 2026–2030 using time-series modelling, including an ARIMA (0,1,0) model with drift.

The results show a strong and sustained increase in total vehicle registrations over the study period, rising from relatively low levels in the early 2000s to 38,346 vehicles in 2025. Growth is characterised by marked year-to-year volatility but a clear upward structural trend, particularly after the mid-2010s and the post-2020 period. Private cars remain the dominant category throughout, followed by motorcycles, both of which drive the overall expansion of motorisation. Commercial and specialised vehicle categories such as lorries, vans, buses, and hire cars show more moderate and stable growth patterns, reflecting their close link to economic activity.

Correlation analysis reveals consistently strong positive relationships across vehicle categories, indicating broad-based expansion of motorisation rather than isolated growth. Forecast results suggest that total vehicle registrations will continue to rise steadily, increasing from approximately 39,666 in 2026 to 44,948 in 2030. Diagnostic tests confirm the adequacy of the ARIMA model, with residuals behaving as white noise and acceptable forecast accuracy.

Overall, the findings indicate structurally persistent motorisation in Guyana, with significant implications for road infrastructure capacity, transport planning, and sustainable mobility policy.

Roasting-Assisted Beneficiation of Magnetite–Apatite Ores: Phase Transformations, Phosphorus Partition, And Selective Recovery

/0 Comments/in /by

Magnetite–apatite ores constitute important resources of both iron and phosphorus but remain challenging to beneficiate because phosphorus-bearing phases commonly occur as finely disseminated apatite, interstitial aggregates, hydrothermal overgrowths, and complex grain-boundary intergrowths within iron oxide matrices. Roasting-assisted beneficiation has emerged as a promising strategy for modifying iron mineralogy, enhancing magnetic susceptibility, improving mineral liberation, and controlling phosphorus distribution. However, existing studies remain dispersed across the following routes: oxidizing roasting, magnetization roasting, selective reduction, additive-assisted roasting, flotation, leaching, dry beneficiation, and smelting. This critical review examines the interactions among ore texture, oxygen potential, roasting temperature, residence time, degree of reduction, phosphorus migration, and beneficiation performance. Particular attention is given to moderate-temperature reduction (approximately 650–800 °C), which frequently provides a more favorable balance between iron recovery and phosphorus rejection than highly reducing metallization-oriented conditions. Thermodynamic and kinetic aspects of the hematite–magnetite–wüstite–metallic iron transformation are discussed together with phosphorus redistribution mechanisms, including apatite preservation, interfacial diffusion, secondary phosphate formation, metallic iron contamination, slag partitioning, and leaching behavior. Comparative analysis indicates that maximum metallization does not necessarily yield optimal beneficiation outcomes, as excessive reduction often promotes the incorporation of phosphorus into metallic iron. Current industrial implementation remains limited by thermal heterogeneity, atmosphere control, energy consumption, and insufficient pilot-scale validation. Future advances require integrated thermodynamic–microstructural modeling, predictive approaches to phosphorus partitioning, and energy-efficient roasting flowsheets that simultaneously enhance iron recovery and phosphorus management.

Sulfuric Acid Regeneration from Magnesium Sulfate Streams: Process Chemistry, Recovery Technologies, and Industrial Challenges

/in /by

Sulfuric acid regeneration from magnesium sulfate streams is an increasingly relevant challenge in hydrometallurgy, mineral processing, battery recycling, pickling operations, and industrial wastewater treatment. Magnesium sulfate is often formed when sulfuric acid reacts with magnesium-bearing minerals, neutralizing agents, or process residues, resulting in acid loss, sulfate accumulation, increased effluent volumes, and challenging brine management. This critical review examines the process chemistry, recovery technologies, and industrial constraints associated with converting magnesium sulfate streams into reusable sulfuric acid or valuable by-products. The discussion covers thermal decomposition, crystallization, membrane-based acid recovery, electrodialysis, diffusion dialysis, solvent-assisted separation, precipitation routes, and hybrid process configurations. Particular attention is given to reaction equilibria, water balance, impurity behavior, energy demand, scaling risk, acid quality, and integration with upstream and downstream unit operations. Although several technologies are technically feasible, industrial application is limited by high energy consumption, low selectivity in multicomponent liquors, fouling, corrosion, and uncertain economics at large scale. The review highlights that magnesium sulfate regeneration should be evaluated as a process-integration problem rather than as an isolated acid-recovery step.

Estimation of carbon sequestration in vineyards in the island of Crete, Greece

/in /by

Climate change consists of a serious global environmental problem and many efforts are focused on its mitigation either by reducing the anthropogenic carbon emissions or by absorbing atmospheric carbon. Agricultural crops usually absorb carbon via photosynthesis acting as carbon sinks. Viticulture is well developed in Crete, Greece since ancient times and the island nowadays produces several well-known grapes and wines. The carbon uptake in Cretan vineyards in Crete has been evaluated. The carbon sequestration rate in vineyards from existing studies in several countries has been used for the evaluation. These studies indicate that carbon uptake in vineyards varies in a wide range of values at 69 – 900 g C m-2 yr-1.  The total surface area of vineyards in Crete is 22,184 ha while their annual carbon sequestration has been estimated at 55,460 t C corresponding at an annual carbon sequestration per capita 0.36 t CO2. Although our results should be considered as indicative, they show that carbon sequestration in Cretan vineyards is not negligible and it should be considered in policy development regarding decarbonization in the island. Our results could be useful to policy makers and to stakeholders of the viticulture industry in the island.

Decarbonization of the Cheese Making Industry on the Island of Crete, Greece

/in /by

Cheese making is a well-developed activity in the island of Crete, Greece since a long time ago. It is mainly based on local sheep’ and goats’ milk while the small-scale cheese making plants in Crete use conventional energy sources to meet their heat and electricity demand. However, solar energy and solid biomass are abundant in the island and they are currently used for heat and power generation. Elimination of carbon emissions in cheese making plants in Crete can be achieved with the replacement of grid electricity and fossil fuels used with local renewable energies such as solar energy and solid biomass. It has been estimated that complete elimination of the operational carbon emissions due to energy use in a small-size cheese making plant in Crete with annual capacity 120 tons cheese can be achieved with the installation of a solar photovoltaic system at 88 kWp for electricity generation and the annual use of 62.86 tons of olive kernel wood for heat production. Additionally, solar thermal systems and high efficiency heat pumps can be used for heat and cooling production. The abovementioned sustainable energy sources and technologies are mature, reliable, cost-efficient and they are currently used in Crete in various sectors. The results of the present study could be useful to all stakeholders of the cheese making industry in the island.

Hydrometallurgical Recovery of Rare Earth Elements from Metallurgical Slags (2020–2026): A Critical Review

/in /by

Metallurgical slags generated from ironmaking, steelmaking, ferroalloy production, and molten salt electrolysis are increasingly recognized as secondary resources for critical raw materials, particularly rare earth elements (REEs) such as scandium, yttrium, and light REEs, which are incorporated into complex silicate, aluminate, and fluoride phases formed at high temperatures. This review critically evaluates hydrometallurgical routes for REE recovery across a wide range of slag systems, including blast furnace, basic oxygen furnace, electric arc furnace, bauxite residue–derived, FCC catalyst, and molten salt electrolytic slags, covering direct leaching approaches (acidic, alkaline, and ammoniacal), hybrid roast–leach processes (sulfation, chlorination, and alkali roasting), and downstream separation techniques such as selective precipitation and solvent extraction. Particular emphasis is placed on the role of slag mineralogy, phase assemblage, and glassy matrices in controlling leaching kinetics, selectivity, and impurity co-dissolution, with silicate-rich slags identified as the most challenging systems due to their polymerized structure, which limits reagent accessibility and often requires thermal pretreatment to achieve recoveries above 80–90%, typically at high reagent consumption (>50–300 kg/t). Comparative evaluation reveals that reported performance is frequently dominated by recovery metrics, while key parameters such as selectivity, reagent intensity, and process integration remain underreported, such that high extraction efficiencies do not necessarily translate into industrial feasibility. The main limitations across existing approaches include silica gel formation, extensive co-dissolution of matrix elements, and the generation of secondary residues, all of which negatively impact process stability and economic viability; moreover, most reported systems remain constrained by poor selectivity, high reagent intensity, and lack of continuous pilot-scale validation, limiting their industrial transferability. Future progress, therefore, depends on shifting from isolated process optimization to integrated, mineralogy-driven process design, supported by reduced reagent consumption, simplified separation flowsheets, and validation under industrially relevant conditions, positioning metallurgical slags as strategic secondary resources capable of supporting diversified and resilient REE supply chains within circular economy systems.

Vat Leaching and Box Leaching in Hydrometallurgy: Process Principles, Industrial Applications, and Future Perspectives

/in /by

Vat leaching and box leaching are proven percolation-based hydrometallurgical methods that provide a controlled alternative to traditional heap and tank leaching. Unlike heap leaching, which works under large-scale, low-control conditions, and tank leaching, which involves fine grinding and intensive agitation, vat and box leaching systems process crushed ores in confined reactors. This allows for better distribution of solutions, faster recovery rates, and a smaller environmental impact. These methods are widely used to extract gold, copper, uranium, and, more recently, rare earth elements from both primary ores and secondary resources. Their main benefits include greater control over leaching parameters (such as residence time, irrigation rate, and solution chemistry), reduced reagent losses, and improved handling of effluents and emissions. However, limitations such as low throughput, the need for prior crushing and sizing, potential channeling effects, and higher capital costs per unit capacity hinder wider adoption. This review explores the fundamental principles of fluid flow, mass transfer, and reaction kinetics in vat and box leaching systems, assesses their industrial use across different commodities, and discusses recent technological developments, including modular setups, hybrid flowsheets, and digital process monitoring. It also highlights key knowledge gaps related to scale-up, modeling multiphase flow in packed beds, and integrating sustainable resource recovery strategies, providing a guide for future research and industry implementation.