Potential Reuse Research Articles

Improving the re-use potential of reactive waste rock using sieving: a laboratory geochemical study

Stockpiles containing sulfide minerals are subject to oxidation reactions when exposed to atmospheric conditions, which can result in the formation of acid mine drainage (AMD). Reactive waste rock has limited re-use potential due to the contamination risk associated with the generated drainage water. The re-use of reactive waste rock could lead to a significant reduction in the volume of waste rock as it mitigates the environmental impact of mine waste deposition. Acid mine drainage generation rate depends on sulfide weathering kinetics which are controlled by many parameters such as the mineralogy and the particle size. Fine fractions of waste rock have higher specific surface areas and degree of liberation of sulfides, resulting in greater reactivity than the coarse fractions. The objective of this research was therefore to evaluate the potential of re-use by controlling particle size using the sieving method. Two different potentially acid-generating waste rocks were divided into six fractions and subjected to both static and kinetic tests. Prediction of the geochemical behavior using static test did not consider the liberation of the minerals, and the long-term prediction was therefore overestimated. Results of the kinetic columns showed there was less oxidation of the sulfide minerals in the coarse fractions than in the fine fractions. Additionally, the distribution of sulfidic minerals and neutralizing minerals with particle size is influencing the potential of the re-use of the reactive waste rock.

Composition and Characteristics of Faecal Sludge from Various Onsite Pit Technologies and User Categories in Dar es Salaam, Tanzania

This study investigates the composition and characteristics of faecal sludge (FS) from different pit technologies (cesspits, pit latrines, septic tanks) and user categories (commercial, industrial, institutional, and residential) in Dar es Salaam, Tanzania, with a view for informed treatment and resource recovery strategies. FS samples exhibited varying concentrations of pH, electrical conductivity (EC), total solids (TS), and volatile solids (VS), COD and nutrients. pH values ranged from 2.83 to 8.41, with no statistically significant differences based on pit technology type or user category. However, the extremely low pH observed in samples from industrial pits suggests possible disposal of industrial chemicals in these sanitation systems. EC levels were notably higher in pit latrines and residential areas, likely due to waste disposal practices in homes, with concentrations 3-5 times above regulatory limits, raising concerns about their impact on treatment effectiveness and re-use potential. TS and VS concentrations also varied, with cesspits showing the highest TS levels and pit latrines exhibiting higher VS, indicating fresher sludge and potential for biogas production, as reflected by a VS/TS ratio ranging from 53.32% to 70.42%. Nutrient analysis revealed elevated levels of phosphate, nitrate and ammonia, particularly in pit latrines and residential pits, highlighting both resource recovery opportunities and challenges for treatment processes. While FS generally fell into the dilute category (TS < 3%), the high concentrations of other parameters underscore the need for a larger treatment footprint per unit volume of FS. The VS/TS ratio suggests that FS is not fully stabilized, indicating potential for further degradation and resource recovery. Additionally, the characteristics of FS suggest potential opportunities for deriving fertilizer and solid fuel. However, ensuring the hygiene of the sludge is crucial for its safe use, particularly in agricultural applications, and further studies are needed to confirm its sanitation.

Promoting Sustainability through the Recycling and Reutilization of Polyethylene Packaging

Abstract The outstanding performance and low carbon footprint of polymeric materials conflict with the sharp growth in plastic trash, which is why the current global plastics economy is largely linear. Reducing environmental problems requires a shift to a circular economy that keeps plastic in its most valuable state and encourages reduction, reuse, and recycling. The existing mechanical recycling procedures are constrained by cost, deterioration of mechanical qualities, and uneven product quality, but mechanical recycling is a crucial instrument in an environmentally and economically sustainable economy of plastics. Through the lens of a circular economy, it’s important to properly sort and recycle (PE) packaging to ensure its maximum potential for reuse. In this paper it discusses the optimum ratio between the recycled and raw (LDPE) pellets in order to create a plastic packaging with the same mechanical, physical and chemical properties with less cost in comparison to the ordinary one. Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive X-ray Spectroscopy (EDX) were used to characterize both raw and recycled (LDPE) pellets. The environmentally friendly LDPE nano-particles in polymer packaging will be tested in the second experimental section, and the results will be compared with those of regular polymer packaging.

Potential reuse of fine sediment from hydroelectric dams and recycled concrete sand in road subgrades

Hydroelectric dams play a crucial role in power generation, water storage, and irrigation. However, their continuous operation has led to sediment accumulation, thereby reducing the water storage capacity and impacting the facility's life span. The aim of the current study is to assess the reuse potential of dredged fine sediment in the composition of road subgrades. Nine types of sediment from diverse hydroelectric dams are analyzed for their chemical, environmental, physical, and geotechnical properties. These sediments then were treated with quicklime and a slag-based hydraulic road binder (3% and 6%, respectively). The current investigation involves evaluating: Proctor parameters, the immediate bearing index, treatment ability, and the mechanical properties of the treated sediment. The results reveal that the properties of treated sediment differ from one mixture to another, thus, indicating that some mixtures meet the criteria outlined in the French Roadworks Guide, by virtue of their clay and organic matter contents. Moreover, the current study explores the impact of incorporating recycled concrete sand (RCS) as a granular corrector to enhance the reuse potential of the sediment in road subgrades. The current findings indicate that adding RCS significantly improves mixture properties, particularly mechanical characteristics, by reaching 1 MPa before 7 days of curing. These promising outcomes pave the way for more advanced road construction practices in ensuring environmental compliance and promoting an eco-friendly reuse of sediment.

Physical-chemical characterisation of an alum-based water treatment sludge in different raw water turbidity scenarios

Characterisation of the water treatment sludge (WTS) generated in drinking water treatment plants (DWTPs) is crucial to define alternatives for its adequate management, including potential reuse options. To define these alternatives, it is necessary to evaluate rainfall seasonality effect on WTS production and its physical and chemical characteristics. This study assessed the production and characterisation of four types of alum-based WTS. The WTS was generated in a pilot-scale system from different raw water turbidities (i.e., low: <5 NTU, medium: 5–10 NTU, high: ≥10 NTU, and very high turbidity: ∼300 NTU) and coagulant doses. To estimate WTS production, mathematical models based on variables such as raw water turbidity, coagulant dosage, and organic matter removed were used. The WTS characterisations included physical (solids and particle size distribution), chemical (metallic oxides, pH, mineral phases), and surface properties (functional groups and zero-charge point pH). The modified Kawamura model presented the best fit (R2 = 1.0, RMSE = 0.1062 and the lower Akaike Information Criterion) for the estimation of WTS production, indicating that at the DWTPs, it is possible to make sludge production projections using only two simple variables: coagulant dose and the raw water turbidity. The four types of WTS consist mainly of amorphous materials (45–65 %), featuring some mineral phases and exhibiting high contents of Al (Al2O3: 30–34 %), Si (SiO2: 21–26 %) and Fe (Fe2O3: 11–13 %). Nevertheless, very high turbidity WTS shows variations in its characteristics, notably a heightened content of clays. As a result of the high concentrations of Al and Fe, the WTS has the potential to be used as coagulants or for the recovery of coagulants, especially low turbidity WTS, which is produced from water with low turbidity and organic matter. The presence of aluminium–silicate clays and the surface functional groups of the silica network suggest that WTS, particularly very high turbidity WTS, also has the potential to be raw materials for generating adsorbents. The potential applications of WTS in coagulation and adsorption can be leveraged in wastewater treatment, promoting the circular economy in the water sector.

Investigating the potential of electrostatic charging to separate cementitious binder and sand

The environmental footprint of concrete is largely influenced by the binder. It is therefore of high interest to investigate the potential reuse of the binder retrieved by modern separation techniques. However, studies found that the recycled cement fraction (RCF) still contained a certain amount of siliceous concrete aggregates, which forms an obstacle in the upcycling of RCF. In this study, the potential of electrostatic separation as a method to separate cementitious binder (hydrated and unhydrated) and sand (silica) is evaluated. Different cementitious powders and silica (sand) were prepared, resulting in a total of 9 powders and 8 mixtures. The mixtures consisted of a combination of silica and one of the cementitious powders (50/50 wt%) with a particle size of the components <125 μm. The potential of the studied technique was evaluated through charging measurements and x-ray fluorescence (XRF). Silica was assumed to contain no CaO and the detected CaO was therefore assigned to the cementitious powders. Results showed that silica and silica-rich fly ash (FA) particles became negatively charged, blast furnace slag (BFS) particles remained largely charge neutral and all other cementitious particles obtained a positive charge. Through electrostatic separation an enrichment of the cementitious binder fraction for all mixtures was obtained at the negative electrode. FA-Silica achieved the highest enrichment (89.9%), CEM III/B-Silica the lowest (4.7%) and the hydrates were enriched ranging from 28.0 to 31.8%.

Produced Water from the Oil and Gas Industry as a Resource—South Kuwait as a Case Study

Produced Water (PW) represents the largest waste stream in the oil and gas industry. As a water resource and as a source of valuable minerals such as alkali salts, it is has been highly under-valued, especially in hyper-arid regions. The beneficial use of PW ranges from water reinjection to elevated oil recovery from reservoirs with almost instantaneous returns, to the extraction of minerals from PW, which involves a number of different processes and setups. The economic value of PW-derived end products offers alternative revenue sources, with market fluctuations and conditions different from those of the hydrocarbon market. The end products of water and industrial salt support local industries such as agriculture, reflecting positively on the gross domestic product (GDP). Furthermore, resource extraction from PW of the oil and gas industry helps countries augment their circular economy. In this regard, the economic feasibility of three scenarios—the use of PW for oil recovery, the use of PW as an alternate source of water and industrial salt, and a hybrid process of both—is explored. The results show that there is great potential for water reuse in Enhanced Oil Recovery operations, as well as in the reduction in freshwater consumption for oil- and gas-extraction operations in the state of Kuwait by up to 4.8 percent when PW generated by SK oilfields is considered, and by 42 percent if PW from all oilfields in Kuwait is reused in the same manner.

Potential improvement in the mechanical performance and thermal resistance of geopolymer with appropriate microplastic incorporation: A sustainable solution for recycling and reusing microplastics

The accumulation of microplastics (MPs) has been a major threat to the natural environment and human health. However, incineration and landfilling may not be appropriate for the management of MPs. This paper evaluated the feasibility of incorporating MPs with diverse dimensions (50 to 500 μm) and contents (2.5 % to 10 %) into geopolymer cured under different temperatures (40 and 80 °C). The compressive (fc) and flexural strength (ff) after curing and thermal exposure (200 to 600 °C) were determined. When cured at 40 °C, fc and ff decreased with percentages of MPs incorporated. By contrast, when cured at 80 °C, the addition of 2.5 % MPs increased fc and ff by up to 33 % (from 52.2 to 69.4 MPa) and 18 % (from 8.2 to 9.7 MPa), depending on MPs’ sizes. The XRD and TGA results suggested that the observed increases in mechanical properties can be attributed to the formation of more calcium alumino (silicate) hydrates (C-(A)-S-H gels) induced by the incorporation of a small quantity of MPs (2.5 %). The SEM images also showed better adhesion between MPs and geopolymeric products when cured under 80 °C, potentially inhibiting crack development. After being exposed to evaluated temperatures (200 and 400 °C), fc of the specimens with 2.5 % MPs and cured at 80 °C was higher than that without MPs. The fc dropped dramatically due to the degradation of MPs between 400 and 600 °C. The increase in strength and heat resistance (up to 400 °C) of MPs-incorporated geopolymer cured under 80 °C indicated the potential recycling and reuse of MPs for geopolymer materials.

Classifiers of Data Sharing Statements in Clinical Trial Records.

Digital individual participant data (IPD) from clinical trials are increasingly distributed for potential scientific reuse. The identification of available IPD, however, requires interpretations of textual data-sharing statements (DSS) in large databases. Recent advancements in computational linguistics include pre-trained language models that promise to simplify the implementation of effective classifiers based on textual inputs. In a subset of 5,000 textual DSS from ClinicalTrials.gov, we evaluate how well classifiers based on domain-specific pre-trained language models reproduce original availability categories as well as manually annotated labels. Typical metrics indicate that classifiers that predicted manual annotations outperformed those that learned to output the original availability categories. This suggests that the textual DSS descriptions contain applicable information that the availability categories do not, and that such classifiers could thus aid the automatic identification of available IPD in large trial databases.

Glass capillary systems for micro-volume fluorometry

Capillary-based fluorometry can be considered a promising alternative to cuvette-based methods, enabling low-volume measurements while reducing analyte consumption and waste generation. In this work, we compared the performance of three types of glass container systems, i.e., anti-resonant hollow core fibers, capillaries, and standard cuvettes, using green fluorescent protein (GFP) as a reference analyte. Among these, when the volume of the analyte and the fluorescence intensity are assessed, a capillary accommodating 2.9 μL was found as an optimal choice. The capillary-based interrogation setup was further optimized to enhance sensitivity by adjusting the florescence-exciting laser beam position and optimizing the capillary’s shape. The obtained capillary-based setup achieved a noteworthy 85 % reduction in sample volume compared to previous studies utilizing capillary-based fluorometry, highlighting its significant contribution to material conservation. The system achieved a limit of detection as low as 26 μg/mL (1.01 nM) GFP concentration and a resolution of 3.5 μg/mL. With its low cost and potential for reusability, capillary-based fluorometry presents a compelling alternative to traditional cuvette-based fluorometry, offering a promising solution for micro-volume analysis.

Development of banana pseudo stem cellulose fiber based magnetic nanocomposite as an adsorbent for dye removal

A hybrid hydrogel nanocomposite derived from cellulose fiber extracted from Banana Pseudo Stem (BPS) was developed as an adsorbent material for wastewater treatment. The hydrogel was developed by graft copolymerization of N-hydroxyethylacrylamide on Cellulose Fiber (BPSCF-g-PHEAAm) with potassium peroxodisulphate (KPS) as an initiator and N, N′-methylene bisacrylamide (MBA) as a crosslinker using microwave irradiation. Magnetic nanoparticles generated by an in-situ method were incorporated into the network structure. Fourier Transform Infrared Spectroscopy (FTIR), Powder X-ray Diffraction (XRD), Thermogravimetric analysis (TGA), Vibrating Sample Magnetometer (VSM), Brunauer-Emmett-Teller analysis (BET), Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive Spectrometer (EDS) were employed. The adsorption capacities of hydrogel and its nanocomposite were evaluated using Methylene Blue (MB) and Crystal Violet (CV) as model dyes. The parent gel exhibited the maximum absorption capacity of 235, and 219 mg g−1 towards MB and CV respectively which was enhanced to 320 and 303 mg g−1 for the nanocomposite. Adsorption data were best fitted with the pseudo-second-order kinetic model and the Freundlich isotherm model. Negative ΔG° and positive ΔH° indicated spontaneous and endothermic adsorption. Desorption was effective to an extent of 99 % in the HCl medium suggesting high reusability potential of the developed adsorbent material.

Revitalizing Golshan and Sharifieh caravanserais: a study in adaptive reuse and urban preservation

The inefficient urban textures often turn into hotspots of social anomalies, leading to depressed, insecure, and non-participatory spaces. The issue of preserving historic urban textures and their dynamic evolution is essential for sustainable urban development. This research delves into the potential for adaptive reuse of the Golshan and Sharifiye caravanserais in the Hamadan city in Iran. These historically valuable structures previously helped in the facilitation of trade and travel; now, they need regeneration. The research, therefore, aims to harness the tourism and functional capacity of the abandoned Sharifiye caravanserai by linking it with the more popular Golshan caravanserai. This link will prevent abandonment and the deterioration of the Sharifiye caravanserai through the creation of an in-between space since it revitalizes both sites. The study emphasizes preserving cultural heritage while at the same time accommodating modern amenities to meet present needs. Therefore, the proposed adaptive reuse method would focus on preserving historical integrity while enabling the building to have a contemporary use. The method then proposes the creation of a transitional zone that transits the historic fabric to modern interventions. The revitalization and reuse of these caravanserais should be able to attract traders, generate hospitable conditions for residents, and increase local income through the tourism generated and the commerce of handicrafts and traditional arts. Effective principles of adaptive reuse are needed to maintain stability in the structure and function of these buildings. The study concludes that a balanced and thoughtful adaptive reuse approach with in-between space can bring transformation in the abandoned space into a lively cultural hub that would contribute both towards economic and cultural development in Hamadan.

Vermifiltration as a green solution to promote digestate reuse in agriculture in small-scale farms

Digestates from low-tech digesters need to be post-treated to ensure their safe agricultural reuse. This study evaluated, for the first time, vermifiltration as a post-treatment for the digestate from a low-tech digester implemented in a small-scale farm, treating cattle manure and cheese whey under psychrophilic conditions. Vermifiltration performance was monitored in terms of solids, organic matter, nutrients, and pathogens removal efficiency. In addition, the growth of earthworms (Eisenia foetida) and their role in the process was evaluated. Finally, the vermicompost and the effluent of the vermifilter were characterized in order to assess their potential reuse in agriculture.Vermifilters showed high removal efficiency of chemical oxygen demand (55–90%), total solids (60–80%), ammonium nitrogen (83–97%), and phosphate-P (28–49%). Earthworms effectively grew and reproduced on digestate (i.e. earthworms number increased by 183%), enhancing the vermifiltration performance, while reducing clogging and odour-related issues. Both the vermicompost and effluent produced complied with legislation limits established for soil improvers and wastewater for fertigation, respectively. Indeed, there was an absence of pathogens and non-detectable heavy metals concentrations. Vermifiltration may be thus considered a suitable post-treatment option for the digestate from low-tech digesters, allowing for its safe agricultural reuse and boosting the circular bioeconomy in small-scale farms.

Rigid–flexible coupling design and reusable impact mitigation of the hierarchical-bistable hybrid metamaterials

Mechanical metamaterials with multistable unit cells featured by negative stiffness or quasi-zero stiffness is attracting increasing attention owing to their unique mechanical properties and reusable potential. In this paper, a hierarchical-bistable hybrid metamaterial with rigid–flexible coupling design is proposed, demonstrating excellent mitigation performance and protection against multiple impacts. The metamaterial consists of a multi-layer bistable beams with a central honeycomb and is manufactured by 3D printing. Firstly, the negative stiffness characteristics of the curved beams in the metamaterial are theoretically determined, and the convergence of the finite element model under different mesh sizes is analyzed. And the quasi-zero stiffness characteristics of the metamaterial have been confirmed, along with its more stable and uniform deformation pattern, through the quasi-static compression experiment. Then the buffering performance of the metamaterial is studied in ball impact tests, showing an average improvement of about 65% compared to the rigid control group, while verifying the accuracy of the finite element model. With the analysis of the deformation modes and strain energy, the mitigation mechanism of metamaterials is demonstrated to extend the contact time and disperse the impact load through the layered deformation to reduce the peak response, instead of relying on plastic strain. Finally, the reusability of the metamaterial is explored by the ten-times plate impacts simulation. The results demonstrate that the metamaterial decreases the plastic strain of its structure by 60% while reducing impact response, thereby preventing the premature failure of core components. These results demonstrate the great potential of the proposed metamaterials for various engineering applications, including aircraft or spacecraft landing protection, vehicle pedestrian protection, and the transportation protection of fragile objects or precision instruments.

Freecycling Markets as Sustainable Materialist Movements?

This paper seeks to redress the over-emphasis on state-driven circular policies in public and academic discourses by attending to two physical community-based freecycling markets at the emerging frontiers of circular waste/resource management in Singapore. Freecycling markets that close short reuse loops are a counterpoint to policies that close long recycling loops. Drawing primarily on empirical data from ethnographic fieldwork, we argue that freecycling markets exemplify a sustainable materialist movement concerned about the sustainability of material resources vis-à-vis the closing/shortening of material circularity loops. This is achieved through the reconfiguration of (a) material flows and (b) material relations. The redirection of unwanted but reusable household objects away from the incinerator and towards potential reusers animates a shift from a linear to circular material flow. We contend that this redirection of material resources for reuse is augmented by rescue and recirculation, which are relatively neglected within the scholarship on circular R-behaviours. Additionally, freecycling markets seek to transform material relations by encouraging care and stewardship, instead of use and disposal. Crucially, we highlight how freecycling markets may be plagued with material constraints that render them not-so-sustainable-and-scalable, thereby shedding light on the practical limits of sustainable materialist action. Taken together, this paper extends the scholarship on circular economies by bringing work on sustainable materialism into a productive dialogue with that on circular activisms and R-behaviours.

Rejuvenated end-of-life reverse osmosis membranes for landfill leachate treatment and reuse water reclamation

Landfills remain a prevalent method for municipal solid waste disposal, yet concerns persist regarding leachate generation and its environmental impact. This research paper investigates the reuse of end-of-life reverse osmosis membranes for treating landfill leachate (LL) after their rejuvenation. The rejuvenation process involved a specific chemical cleaning procedure that allows for permeability recovery without compromising the membrane rejection capacity when compared to o pristine reverse osmosis. It was also explored the hypothesis how previous membrane use affects the rejuvenation process by considering end-of-life membranes used for desalination of brackish water and treated water. While both could be effectively rejuvenated, those used for brackish desalination were more susceptible to irreversible fouling. In such cases, recycling the membrane and converting it to porous ultrafiltration or microfiltration membranes is recommended. For membranes previously used for treated water desalination, it was observed high efficiency in LL treatment across multiple filtration cycles. The average flux for these membranes corresponded to 6.9 ± 0.4 L/m2h (operating pressure: 10 bar), and the rejection were greater than 89.4 % for chemical oxygen demand and 98.6 % for color. In complement, it was investigated the contribution of pretreatment with ultrafiltration membranes. Ultrafiltration was effective in preventing membrane fouling and improving the physicochemical quality of reclaimed water from landfill leachate. Overall, this research provides valuable insights into the potential reuse of end-of-life reverse osmosis membranes from treated water desalination plant for LL treatment, contributing to sustainable waste management and wastewater treatment solutions.

Design of biocompatible gelatin hydrogels reinforced with magnetite nanoparticles: Effective removal of chromium from water environment

The development of biocompatible adsorbents is vital for environmental remediation to control and reduce pollution and waste accumulation in ecosystems. Biocompatible hydrogels represent an innovative class of materials that are primarily composed of polymer chain units forming their structural framework. They have a high affinity for water molecules. This research thus aims to incorporate iron oxide particles into the gelatin matrix to produce gelatin hydrogel beads to remove hexavalent chromium from an aqueous solution. The synthesized beads, known for their consistent size, low friction, high specific surface area, mechanical stability, and lightweight characteristics, demonstrated their suitability for various industrial applications. The effectiveness of these hydrogels in removing hexavalent chromium ions was confirmed through a thorough analysis using techniques such as FTIR, TGA, SEM, EDX, VSM, and XPS. Batch experiments revealed that the gelatin-based nanocomposite beads exhibited optimal adsorption efficiency under acidic conditions, lower initial concentrations of chromium ions, extended contact time, and elevated temperature (50–60 °C). The composite achieved a maximum removal efficiency of 99% at pH 1, with an adsorbent dose of 0.5 g at 50 °C, and an initial concentration of 50 mg per liter. The use of 0.7 N NaOH in the regeneration process resulted in a commendable 70.5% desorption efficiency, enabling potential reuse and regeneration. Significantly, the desorption efficiency remained consistently high even after four desorption-readsorption cycles, contributing to the economic and environmental sustainability of chromium removal. Additionally, the study determined that the sorption process was feasible, spontaneous, and endothermic. These collective findings suggest that magnetic gelatin hydrogel beads could serve as a cost-effective alternative adsorbent for the efficient removal of chromium ions from aqueous solutions.

Post-fire structural material behaviour of high- and ultra-high-strength steels – Experimental study and aids for assessment for further use and potential reuse after fires

A thorough understanding and realistic modelling of the essential post-fire material behaviour is crucial for a safe assessment of the residual structural performance of steel components and the reliable further usage of steel structures after fires. This paper presents a comprehensive experimental study of the constitutive material behaviour after heating-cooling cycles of two quenched and tempered high-strength steels (S690QL, S960QL) as well as two thermomechanically rolled steels (S960M, S1100M). The results are compared to both the behaviour of grade S355J2+N mild steels and a comprehensive database of existing post-fire tests. Except for high- and ultra-high-strength steels, which are exposed to very high temperatures above the A1-phase-transformation-temperature during fires, the assumption of reversibility of the mechanical properties for structural designs of steel structures has been confirmed. At high and very high steel temperatures, the microstructure changes and the strength properties after fire are significantly lower than those of virgin high-strength steel specimens. The study thus provides the basis for reliable structural designs and future normative guidance of the post-fire structural steel designs.

Distribution of Heavy Metals in the Surrounding Mining Region of Kizhnica in Kosovo

This study investigated the distribution of heavy metals in agricultural soils in the vicinity of three large mining landfills of the Kizhnica mine in the Republic of Kosovo. The mining sector is one of the most important sectors of Kosovo’s economic development, and the Kizhnica mine is one of the most important ore producers in Kosovo. Besides the positive aspects, the development of production also has some negative side effects, such as the generation of industrial waste and the possible contamination of surrounding areas, including agricultural land. Therefore, ten sampling sites were selected in the vicinity of the Kizhnica mine. These sites were characterized and assessed as the most important due to the anthropogenic impact of mineral processing and open-tailing waste deposits in Kizhnica. The concentration of Pb, Zn, Cu, As, Cd, Ni, Mn and Sb in the selected samples was determined using inductively coupled plasma–optical emission spectrometry. The data obtained were used to create geochemical maps and calculate the contamination factor, pollution load index and geoaccumulation index. Cluster analysis, Pearson correlation coefficient and air spatial distribution patterns using the air dispersion model were used to evaluate within the area. The results showed that heavy metal levels are influenced by the anthropogenic nature of pollution, confirming a current ecological threat from mining activities in the region. In order to improve waste management, reduce the hazardous impacts of mining and contribute to the sustainable development of the region, the potential reuse of the deposited waste material in the construction industry is proposed.

Solution for crop classification in regions with limited labeled samples: deep learning and transfer learning

ABSTRACT Reliable classification results are crucial for guiding agricultural production, forecasting crop yield, and ensuring food security. Generating reliable classification results is relatively simple in regions with sufficient labeled samples, but regions with limited labeled samples remain a significant challenge. In this study, we propose two new solutions that leverage the feature representation capabilities of deep learning and the sample reuse potential of transfer learning to solve the limited label problem. Specifically, we develop a Variable-dimensional Symmetric Network with Position Encoding (VPSNet) to improve the efficiency of labeled sample utilization. Additionally, we introduce a transfer strategy based on the Inter-Regional Discrepancies in Crop Time Series (IRDCTS) to expand the labeled sample reuse region. We evaluated the proposed model in three regions with limited labels between 2017 and 2018. Experimental results show that our model has superior discriminative feature extraction capabilities compared to other existing models. The feasibility of the proposed transfer strategy is tested in three pair regions, showing that IRDCTS can enhance the model adaptability by reducing inter-domain discrepancies. This study provides a comprehensive solution to the classification problem of the limited labeled samples, involving both the development of classification models and the implementation of transfer strategies.