Abstract: Dissolved oxygen (DO) management is a primary challenge in intensive aquaculture, where conventional aeration often suffers from high energy costs and low efficiency in decentralized systems. Oxygen transfer kinetics were investigated under oxygen-depleted conditions (initial DO = 2.4 mg L⁻¹) using the dynamic method. The system's performance was characterized through the volumetric mass transfer coefficient (kLa), Specific Oxygen Transfer Efficiency (SOTE), and dimensionless analysis (Reynolds, Schmidt, and Sherwood numbers). After 1 hour of operation, the DO concentration increased to 6.2 mg L⁻¹, achieving a net oxygen transfer of 9.55 ± 0.46 g. The system yielded a kLa of 1.44 h⁻¹ (R² = 0.97) and a SOTE of 76.4 ± 7.8 gO₂ kWh⁻¹. Dimensionless analysis (Re ≈ 2 x 10⁴, Sc ≈ 500, Sh ≈ 682) confirms that oxygen transfer is governed by hydrodynamic-induced interfacial area generation rather than molecular diffusion. Biological validation demonstrated that fish (catfish) grown under nanobubble-assisted conditions achieved a 43% higher growth rate over 17 days compared to non-assisted groups. These findings demonstrate that hydrodynamically controlled nanobubble spray systems provide an energy-efficient and scalable solution for decentralized aquaculture aeration.

Abstract: This study examines the impact of regrinding on the interfacial properties of sulfide minerals and the flotation performance of weathered copper-porphyry tailings. The feed material is characterized by a low copper grade (0.17%) and a high proportion of oxidized species (53.84%), which contributes to its inherent chemical stability and poor flotation kinetics. The findings indicate that regrinding serves a dual role: facilitating the liberation of mineral intergrowths and inducing mechanical surface renewal. This renewal is characterized by a significant decrease in the oxidation-reduction potential (ORP) and an intensification of the surface reactivity. Experimental results identify an optimal grinding fineness of 77-81% passing -0.045 mm, yielding a copper recovery of 16.26% in the absence of a sulfidizing agent. The integration of sodium sulfide (400 g/t) with regrinding significantly enhances recovery to 36.37%, driven by the establishment of a reducing environment (ORP ≈ -150 mV) and the chemisorption-mediated activation of mineral surfaces. While ultrafine grinding (90-100% passing -0.045 mm) further increases recovery to 51.47%, it is accompanied by deleterious sliming effects and a subsequent loss of process selectivity. The study confirms that mechanical surface rejuvenation and the optimization of electrochemical conditions are critical for improving the processing efficiency of anthropogenic resources, providing a theoretical framework for establishing rational beneficiation regimes.

Abstract: This study investigates hybrid brake-pad composites made by adding different percentages of silicon carbide (15% and 20% SiC) and zinc oxide (10%, 15%, and 20% ZnO). The goal was to find a composite that improves brake working efficiency. Wear and hardness tests were carried out according to ASTM standards. The experimental results were analyzed using Design of Experiments method to study how wear changes over time under different loads. Time-series trend analysis visualizes how the specific wear rate developed. The results showed that sample A5 had the best wear resistance and certified A5 as the optimum structural stability over time composite sample. The hardest samples were A2 and A5. The best composite was selected for a static structural analysis using ANSYS 2022-R1 to evaluate stress, strain, deformation, and elastic energy. The thermal analysis examined heat distribution, heat generation, and heat flux in the hybrid composite material. The numerical results showed that stress levels are lower at outer surfaces compared to the inner regions. The outer surfaces exhibit a uniform distribution heat flux. Directional heat flux showed a slight increase near the inner radius, the disk protrusions and edges. These findings clarified how the optimal composite behaves under braking conditions.

Abstract: The advancement of technology has improved the supply chain of major sectors of the economy, including construction. Thus, digital technology may advance the transition from the conventional practices to the Construction 4.0 environment, particularly in developing countries. Studies are scarce concerning the role of technology as a key driver of digital transformation in Construction 4.0 Adoption in the South African construction sector. Thus, this study appraises digital technologies for construction project execution and sheds light on the role of technology as a key driver of digital transformation in Construction 4.0 Adoption in the South African construction sector. The study utilised a qualitative approach and included face-to-face semi-structured interviews with 50 participants in South Africa who are knowledgeable in Construc-tion 4.0 and digital technology. The researchers also adopted thematic analysis using Atlas.ti and NVivo to analyse the data. The findings reveal that the benefits of digital technologies for construction project execution in the South African construction sector, and, by extension, for transforming conventional practices into Construction 4.0, can-not be overstated if well embraced and implemented. Findings also identified the key technologies driving digital transformation in Construction 4.0 Adoption in the South African construction sector, grouping them into six sub-themes. This study contributes to the theoretical discourse on technology as a primary driver of digital transformation in the context of Construction 4.0 adoption. It also offers practical insights into project resilience and the role of adopting digital technologies in the construction industry, particularly in the South African construction industry context.

Abstract: Wastewater treatment plants (WWTPs) are significant contributors to anthropogenic greenhouse gas (GHG) emissions through both direct biological processes generating methane (CH₄), nitrous oxide (N₂O), and biogenic carbon dioxide (CO₂) and indirect energy consumption. This comprehensive research paper synthesizes findings from 30 peer-reviewed studies to present a holistic analysis of carbon footprints in wastewater treatment, with a specific quantitative assessment of a sequencing batch reactor (SBR) facility processing 5,000 m³/day. The analysis reveals that N₂O emissions can constitute up to 75% of a plant's carbon footprint, while aeration accounts for 40–75% of the total energy consumption. The carbon footprint of WWTPs varies by treatment technology, scale, and operational conditions, ranging from 61 to 161 kg CO₂e per population equivalent (PE) annually. For the 5,000 m³/day SBR facility, baseline emissions range from 365 to 1, 095 tCO₂e annually and can be reduced by 30–50% through anaerobic digestion with biogas recovery and anoxic phase optimization. The findings underscore that achieving carbon neutrality requires extending accounting beyond plant boundaries to include effluent exports, sludge management, and urban infrastructure integration. This paper provides a unified framework for understanding, quantifying, and mitigating carbon emissions from wastewater treatment, with particular emphasis on SBR technology.

Abstract: The topology optimization of reinforced concrete (RC) building frames is relatively underexplored compared to steel structures, partly due to the lack of a systematic approach to generate and select ground structures (GS). Existing methods often use less systematic GS strategies, limiting efficient exploration of the vast and sparse design space shaped by large bay widths and story heights. This work addresses this gap by providing a comprehensive and systematic pipeline tailored for RC frames. The key contributions are: (1) development of a GS generation framework that systematically enumerates all feasible RC frame configurations within user-defined constraints, (2) introduction of a candidate GS selection map, a surrogate-based tool employing graph-based Latin Hypercube Sampling (LHS) and sparse Gaussian Process (GP) models, which predicts compliance early and strategically guides candidate selection, significantly reducing computational cost while serving as a reference for understanding design parameter influences; and (3) implementation of an integrated topology optimization pipeline applying particle swarm optimization (PSO) to selected candidates, achieving efficient compliance minimization with reduced computational effort. The complete workflow - which spans GS generation, surrogate-based candidate selection, and iterative optimization - is implemented and validated in two design domains with width-to-height aspect ratios of 1:1 and 1:1.5 and generates 438,984 and 104,032 different frame configurations respectively. The selected candidates undergo PSO-based optimization, yielding designs with volume fractions below 0.55 and preserving critical floor beams, demonstrating the framework’s ability to enable the design of structurally efficient RC frames. The framework is designed to be extensible, with direct applicability to broader RC design scenarios including three-dimensional frames and nonlinear analysis in future work.

Abstract: This article is representing numerical research and modeling of autonomous unmanned underwater vehicle’s (AUUV) control system for planar motion. A mathematical model of the control system is designed for an underwater vehicle, the structure of which consists of a main thruster and control surfaces. Based on the dynamic AUUV's mathematical model two types of planar motion equations have developed: simple planar motion equations and extended planar motion equations. Both equations types include AUUV’s geometrical characteristics and hydrodynamics coefficients which have determined from computer aided design and CFD simulation. The difference between simplified and extended equations of planar motion consists in the inclusion of an additional planar coordinate and extra hydrodynamic coefficients. For each type of motion equations as input signal typical maneuverers, such as constant value, sin value and Kempf maneuverer (zig-zag maneuverer) have implemented. The system's output signals from external actions in the form of typical maneuverers the estimated of necessity of regulator. As regulator were chosen and used the PID-regulator for velocity and yaw control. The results of this study also demonstrate what the engine thrust required to achieve the desired speed, and identify which equations of motion are appropriate for specific maneuvers performed by the apparatus during its operation and mission execution.

Abstract: Composite wing structures are widely used in unmanned aerial vehicles (UAVs) because of their high specific strength and stiffness, but they are vulnerable to localized impact events such as tool drops, runway debris and small bird or drone strikes. In many aerospace applications, carbon fiber–reinforced polymers (CFRP) are preferred for their high stiffness and weight efficiency, although they tend to fail in a brittle manner and are expensive. E-glass fiber composites, on the other hand, are tougher and cheaper, but usually considered less competitive in stiffness and impact resistance. This study numerically investigates the impact resistance of optimized E-glass fiber composite UAV wing skins compared with aerospace-grade carbon fiber skins, both supported by balsa-wood cores. A 3D finite element (FE) model of a 600 mm semi-span UAV wing segment was developed in Abaqus/Explicit, with a user-defined VUMAT implementing an orthotropic elastic law and a Hashin-type progressive damage model. A rigid spherical impactor (radius 8 mm) with various mass velocity combinations (0.5 kg at 5000 and 10 000 mm/s, and 1.0 kg at 20 000 mm/s) was used to represent low, medium and high energy impacts. E-glass material sets were defined and gradually improved, within realistic mechanical limits derived from published E-glass/epoxy systems, until a “maximum experimental limit” E-glass configuration was obtained. This optimized E-glass wing skin was then compared with carbon-fiber configurations taken as benchmark aerospace. The comparison is based on peak contact force, penetration or non-penetration, absorbed energy, and damage extent in the skin and sub-structure. The study also proposes a coupon- and sub-component-level experimental programme to validate the numerical predictions using drop-weight impact tests on E-glass and carbon-fiber laminates and on a scaled UAV wing segment. These findings indicate that suitably engineered E-glass composites can be a viable, cost-effective alternative to carbon fiber for impact-resistant UAV wing structures.

Abstract: Climate change poses significant challenges to the operation and safety of dam and reservoir (D&R) systems, particularly in regions characterized by water scarcity and high climate variability. This study presents a structured methodology for climate risk assessment that integrates regional climate projections, system-specific thresholds, and a semi-quantitative risk matrix approach. A key innovation is the explicit linkage between climate indicators and system performance through physically based thresholds, combined with empirically derived exceedance probabilities from high-resolution climate projections. The methodology is applied to the Almopeos D&R system in Northern Greece using an ensemble of statistically downscaled CMIP6 simulations under two emission scenarios (SSP2-4.5 and SSP5-8.5) and two future periods (2041–2060 and 2081–2100). Three climate indicators are analyzed: TX35 (temperature extremes), CDD (consecutive dry days), and Rx1day (extreme precipitation). Results indicate that temperature increase is the dominant climate risk hazard, leading to increased irrigation demand and reduced system reliability, with risks classified as high to very high. Drought conditions represent a secondary but important risk, becoming critical during prolonged dry periods affecting reservoir storage, while extreme precipitation events exhibit low likelihood but potentially high consequences for dam safety. Adaptation measures are prioritized using a qualitative multi-criteria approach, highlighting the effectiveness of operational measures, while structural and monitoring interventions remain essential for ensuring system safety. The proposed methodology provides a transparent and transferable framework for climate-resilient planning of water infrastructure systems.

Abstract: Laminated Veneer Lumber (LVL) is engineered product produced by adhesively bonding fast growing Poplar veneers. Comparing dimensional lumber, LVL provides better use rate and fulfills structural wood requirement for wood structure building. And have proven this thing about the lateral mechanical properties for LVL shear walls, also have done investigations into what the hold downs and the loads of those that get put into it do to them when trying out these types of things in an effort to study their lateral mechanical workings. Comparisons with different types of wooden shear wall structures were carried out for this reason. According to the research data obtained through experiments and analyses, suggestions were proposed to designers regarding how they might go about designing hold-down devices in cases wherein these were employed with respect to particular kinds of shear walls which themselves had their own particular features and attributes.

Abstract: The article discusses the methods for classifying processes for testing and processing metals by plastic deformation, based on the characteristics of their stress-strain state. The basic methods for determining the stress and strain states using fundamental scalar quantities representing the stress and strain tensors are discussed. Equations have been derived for the quantitative determination of the type of stress-strain state through a combination of principal stresses, represented as the strain rigidity of the deformation mode. A classification of deformation processes for testing and processing metals by plastic deformation is proposed, using the stress triaxiality parameter and the strain rigidity coefficient. Some 2D and 3D diagrams have been created based on simulation modeling of plastic deformation processes using virtual tools, allowing the grouping of processes according to the measured principal stresses and their combinations, which represent the stress triaxiality and strain rigidity of the deformation mode. By determining the type of grouping in these diagrams and the change in the stress-strain state with increasing strain levels, the characteristic features of the deformation processes used in materials testing and in the processing metals by plastic deformation of metals/alloys have been confirmed.

Abstract: This study develops a comparative screening framework for evaluating the feasibility of low-temperature clinker production using waste-derived raw meals under melt-phase and Fe-in-liquid constraints. The work addresses the need to connect two strategies for lower-emission cement manufacture that are often discussed separately: partial substitution of conventional raw materials with waste-derived inputs and reduction of clinker burning temperature through mineralized processing. A secondary-data analysis was conducted using selected open-access case studies and an open-access spreadsheet dataset, from which quantitative variables related to composition, process conditions, clinker formation, and cement performance were extracted and compared. The results show that feasibility depends not only on burning temperature, but also on major-oxide compatibility, minor-element constraints, burnability, clinker phase balance, melt-related indicators, and final cement performance. In the waste-substitution benchmark, MSWI bottom ash was compositionally feasible only within a limited substitution range controlled by Fe2O3 content. In the mineralizer benchmark, a reduction in burning temperature from 1450 ∘C to 1350 ∘C was found to be a practical benchmark for reduced-temperature clinker production, whereas further reduction to 1300 ∘C required stronger chemical assistance and led to performance penalties. Overall, the proposed framework distinguishes favorable, conditionally feasible, and constrained pathways and provides a basis for screening candidate systems before experimental validation.

Abstract: This study presents a comprehensive characterization of recycled aluminum briquettes produced by cold pressing of Al–Si–Mg alloy machining chips, along with an evaluation of their behavior during subsequent remelting. The objective was to assess the density, porosity, chemical composition, and metallurgical yield of the briquettes before and after melting, as well as to determine their suitability for use as deoxidizing additives in steelmaking. The cold-pressed briquette (Sample A) exhibited a low density of 2.29 g.cm-³ and a porosity of 12.1%, resulting from intergranular voids and residual lubricants. After melting and resolidification (Sample B), the density increased to 2.388 g.cm-3 and the porosity decreased to 8.15%. XRF chemical analysis confirmed a high degree of elemental homogeneity after melting with no indication of segregation, while SEM–EDS microstructural analysis verified the absence of significant intermetallic phases and revealed only a thin surface oxide layer. The metallurgical yield reached 94.2% with a low dross content (2.25%). The results demonstrate that, following appropriate preprocessing and optimized compaction, recycled aluminum briquettes constitute a stable and efficient secondary aluminum material suitable for steel deoxidation, and they can significantly reduce the environmental impact of metallurgical production.

Abstract: High Velocity Oxy-Fuel (HVOF) thermal spraying is widely used for the deposition of dense coatings with low porosity, high hardness, and superior fracture resistance. Tungsten carbide–cobalt (WC–Co) coatings are extensively employed in industrial and aerospace applications due to their excellent wear resistance and mechanical performance; however, further improvement in crack resistance and adhesion remains a key challenge. In this study, WC–Co+Ni composite coatings were deposited on ductile cast iron by HVOF, with particular emphasis on the role of Ni particle addition in tailoring coating microstructure and performance. Microstructural characterization was carried out using light, scanning, and transmission electron microscopy (LM, SEM, TEM), while phase composition and chemical analysis were determined by X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS). The coatings exhibited a dense, low-porosity microstructure composed of partially molten Ni particles and fine WC and W₂C carbides embedded in a cobalt-based matrix, with locally nanocrystalline features. XRD analysis confirmed WC and W₂C as the dominant phases, with weak reflections indicating the possible formation of the η-phase (Co₆W₆C). Mechanical and tribological performance, evaluated by instrumented indentation and scratch testing, showed that Ni addition significantly enhances crack resistance, wear resistance, and coating–substrate adhesion. The results demonstrate that Ni-modified WC–Co coatings deposited by HVOF enable effective microstructural design, leading to improved durability and performance, which makes them promising candidates for advanced coating applications.

Abstract: The construction industry remains one of the largest contributors to global carbon emissions, with ordinary Portland cement (OPC) production accounting for a significant share due to high energy consumption and carbon intensive clinker manufacturing processes. As infrastructure development accelerates worldwide, particularly in rapidly urbanizing regions, the demand for sustainable construction materials has become urgent. In recent decades, alternative cementitious materials (ACMs), including fly ash, ground granulated blast furnace slag (GGBS), silica fume, and rice husk ash, have gained attention as partial replacements for OPC in concrete mixes. This research paper investigates the geotechnical and environmental impacts associated with the use of alternative cementitious materials in concrete, emphasizing real world construction conditions and performance requirements. The study evaluates the influence of ACMs on parameters such as soil–structure interaction, compressive and long term strength development, durability under aggressive environmental exposure, permeability characteristics, and resistance to chemical attack. Environmental performance indicators including carbon footprint reduction, energy savings, industrial waste utilization, and lifecycle sustainability are also assessed. Experimental findings and recent literature indicate that ACM based concrete exhibits reduced permeability, enhanced resistance to sulfate and chloride ingress, and improved long term mechanical performance compared to conventional OPC concrete. These contribute to improved geotechnical behavior in foundations exposed to adverse soil conditions. Furthermore, adopting alternative cementitious materials can reduce greenhouse gas emissions while supporting circular economy principles. The study concludes that integrating ACMs into concrete production is an approach for construction without compromising geotechnical performance or structural reliability.

Abstract: This article identifies, using a zero-shot method (Gen6d), the 3D-bounding box of a target far-distanced from a UAV. Furthermore, it infers the attached camera’s pose to the drone, based on the underlying training on the visual data. These visual data are used in a YOLO-framework to identify targets belonging to a class. The vertices of the orthogonal 3D-box are used in a visual-servoing scheme on the attached gimbal on UAV. The camera has a varying focal length (zoom) and the indirect objective is to move the UAV close to the target while reducing the zoom factor. Initially, the UAV starts with a large zoom-factor (36×) at a far distance (100m) from the target. The UAV approaches the target using the visual servoing scheme, while reducing its zoom at discrete steps and maintaining its focus. Experimental results indicate the efficiency of the proposed method.

Abstract: Environmental governance in the Global South increasingly unfolds within complex socio-technical systems characterized by fragmented institutional capacities, distributed sensing infrastructures, and high socio-ecological uncertainty. In this context, Digital Twins have emerged as a promising paradigm for integrating cyber-physical systems with decision intelligence, yet most implementations remain limited to industrial optimization or urban infrastructure management. This article proposes an architectural framework for Digital Twins oriented toward environmental governance by integrating Artificial Intelligence of Things (AIoT) monitoring networks with complex systems modeling and cybernetic governance principles. Methodologically, the study combines conceptual development grounded in systems science and the Viable System Model (VSM) with an illustrative empirical case study from the Caribbean Mining Corridor in Colombia, where a distributed AIoT environmental monitoring network operates within the Hub Ambiental del Caribe initiative. The proposed architecture links real-time environmental sensing, predictive analytics, and recursive governance structures to enable anticipatory environmental decision-making. The results demonstrate how Digital Twin infrastructures can function as cybernetic platforms that transform fragmented environmental data into actionable decision intelligence across institutional levels. By embedding feedback mechanisms, open environmental data governance, and participatory monitoring capacities, the framework supports adaptive management in highly dynamic socio-ecological contexts. The study concludes that Digital Twins designed as governance infrastructures—rather than purely technical replicas—can significantly enhance environmental decision support systems and foster climate justice-oriented transitions in vulnerable territories of the Global South.

Abstract: The production of biosolids in Brazil has increased due to the expansion of Sewage Treatment Plants, making these materials a sustainable alternative for agricultural use. Composed of high organic matter and nutrients such as nitrogen, phosphorus, calcium, and magnesium, biosolids have the potential to improve the physical, chemical, and biological properties of tropical soils, contributing to greater fertility, water retention, and microbial activity. National literature demonstrates that these materials can par-tially replace mineral fertilizers and assist in the recovery of degraded areas. On the other hand, the presence of contaminants still represents a challenge. Heavy metals such as Cd, Pb, Ni, and Hg generally appear in low concentrations, while Cu and Zn tend to approach the maximum limits established by CONAMA Resolution No. 498/2020. Regarding pathogens, the efficiency of sanitization depends on the treatment method employed. Emerging organic pollutants, including pharmaceuticals and hor-mones, have been detected, but still lack specific regulations in Brazil. Thus, although biosolids present high agronomic potential, their safe use requires adequate monitor-ing, improvement in controlling the origin of sewage, and advances in legislation, es-pecially regarding emerging organic pollutants.

Abstract: The fabrication of complex architectures remains a central challenge in 3D bioprinting, where low mechanical properties of hydrogels restrict the range of feasible geometries. Four-dimensional (4D) bioprinting can mitigate these limitations by introducing programmed structure shape-morphing in response to external stimuli. However, in most existing approaches, shape-morphing behavior is introduced after hydrogel formation, limiting the complexity of the resulting deformation. Here, a proof-of-concept strategy is presented, in which shape-morphing is directly encoded during fabrication. By modulating light exposure time layer-by-layer in vat photopolymerization, spatial variations in crosslinking density are introduced in situ within GelMA hydrogel constructs. Upon immersion in aqueous media, these variations generate differential swelling, leading to controlled bending of the printed structures. This approach enables the programming of deformation pathways at the printing stage, without requiring additional materials or post-processing steps. The morphing behavior was further supported by finite element simulations, which reproduced the experimentally observed deformation and enabled prediction of the shape change. Overall, this study demonstrates that swelling-driven actuation can be encoded during fabrication. Although demonstrated on simplified geometries, this approach provides a versatile framework for process-driven shape morphing programming and represents a step toward more spatially resolved and potentially volumetric 4D bioprinting strategies.

Abstract: The development of supersonic aircraft presents significant challenges in ensuring safety during early design stages, particularly for fuel tank systems exposed to extreme thermal and structural loads. Conventional document-based zonal safety analysis methods are limited in their capacity to identify hazards at the conceptual design phase. This study proposes an integrated framework combining computer-aided design (CAD) and model-based systems engineering (MBSE) to support early-stage zonal hazard analysis. The framework links spatial subsystem modelling with functional system architecture to enable iterative hazard identification and mitigation. Applied to the SA-24 Phoenix conceptual supersonic aircraft, the approach identifies critical risks, including fuel vaporization, over-pressurization, and structural fatigue, and evaluates mitigation strategies such as thermal insulation and redundant venting. Functional hazard analysis and fault tree analysis are used to assess failure scenarios and ensure compliance with EASA CS-25 requirements. Results indicate an estimated 40% reduction in risk priority number values for key thermal hazard pathways and a 25% reduction in conceptual design iteration time compared with conventional approaches. The findings demonstrate that CAD–MBSE integration offers a scalable and efficient methodology for early hazard identification, contributing to safer and more reliable supersonic aircraft design.