Search Results (331)

Investing in large-scale hydropower is on the rise in Ethiopia in accordance with the country’s climate-resilient green economy strategy. Rural electrification is a top priority on the development agenda of the country, with very limited off-grid interventions. Although small-scale hydropower can bring various social and economic benefits compared to other off-grid solutions, it is hardly localized in the country. The motivation for this research is to break this technological bottleneck by synergizing and strengthening the local capacity. Accordingly, this paper presents the full-scale crossflow turbine design and development process of a power plant constructed to give electricity access to about 450 households in a rural village called Amentila. Based on a site survey and the resource potential, the power plant was designed for a 125 kW peak at 0.3 m³/s of discharge with a 53 m head. The crossflow was selected based on the head, discharge, and simplicity of development with the available local capacities. The detailed design of the turbine and its auxiliary components was developed and simulated using SolidWorks and CFD ANSYS CFX. The power plant has a run-of-river design, targeting provision of power during peak hours. This study demonstrates an off-grid engineering solution with applied research on the water–energy–food–environment nexus. Full article

This paper presents a mathematical modeling and numerical analysis of fluid-thermal processes in a two-stage steam turbine cascade, focusing on the application and comparative assessment of turbulence models in computational fluid dynamics (CFD) simulations. Using the finite volume method implemented in the ANSYS CFX-Task Flow (ANSYS CFX 2022 R2) workflow, the study investigates the performance of standard k-ε, k-ω, and SST turbulence models in predicting flow structures, pressure fields, and velocity distributions within the turbine flow passages. The governing equations, including the Reynolds-Averaged Navier–Stokes (RANS) equations and associated energy and constitutive relations, are solved in conservative form under compressible flow conditions. Experimental data from turbine tests performed at the Institute of Fluid Machinery at Lodz University of Technology are used for validation. Results demonstrate that turbulence modeling significantly influences the accuracy of predicted flow phenomena. The study identifies strengths and limitations of the models in capturing complex three-dimensional flow structures and provides quantitative error margins and practical guidance for their application in industrial turbine flow simulations. Full article

This study employed the hydrothermal coprecipitation method to grow CoAl-layered double hydroxide (LDH) onto bacterial cellulose (BC) in situ, successfully preparing the CoAl-LDH@BC composite. This composite was then used to activate peroxymonosulfate (PMS) for tetracycline (TC) degradation. According to the results, the CoAl-LDH@BC/PMS system demonstrated a remarkable removal efficiency of 99.9% for TC within 15 min. Moreover, the influencing factors of catalyst dosage, PMS dosage, TC concentration, reaction temperature, initial pH, and inorganic ions were evaluated. Notably, the system demonstrated broad-spectrum contaminant removal capabilities, which could simultaneously eliminate more than 99.7% of oxytetracycline hydrochloride (TCH) and 87.9% of ciprofloxacin (CFX) within 20 min. Additionally, the removal rates for several dyes reached more than 95.7% in 20 min. Phytotoxicity assessment (using mung bean seeds) confirmed a significant reduction in the biotoxicity of post-treatment TC solutions. The identification of TC degradation intermediates was enabled, alongside the subsequent proposal of plausible degradation pathways. Furthermore, mechanistic investigations based on radical quenching experiments revealed the coexistence of dual radical (•OH and${ \mathrm{SO}}_4^{-}•$) and non-radical (¹O₂) oxidation pathways in the reaction of the CoAl-LDH@BC/PMS system. Overall, this research broadens the potential applications of bacterial cellulose-based porous materials and provides an innovative insight into antibiotic wastewater treatment. Full article

Background: Bovine mastitis (BM) is a major disease affecting dairy herds (DHs), with Serratia marcescens (S. marcescens) being increasingly implicated as a causative agent. The growing concern over antimicrobial resistance (AMR) extends to BM-associated S. marcescens isolates, where resistance patterns are emerging. Methods: Here, four BM Gram-negative isolates were investigated: 1-DH1, 2-DH1, 3-DH2, and 4-DH3. Phenotypic characterization was performed using the Neg-Urine-Combo98 panel on a MicroScan WalkAway Plus system. Whole-genome sequencing (WGS) was performed to characterize and identify AMR and virulence factors (VF) genes and plasmids in isolates 1-DH1, 3-DH2, and 4-DH3, and phylogenomic analyses were conducted for a visual comparison of the genomes. Results: Phenotypically, isolates 1-DH1, 2-DH1, and 4-DH3 were identified as S. marcescens, and 3-DH2 as Serratia odorifera (confirmed as S. marcescens by WGS). A 28.00% (n = 25) prevalence of phenotypic AMR for isolates 1-DH1, 2-DH1, and 4-DH3 against Aug-E, AM, To, Cfx, Crm, Cl, and Fd was shown, and 24.00% (n = 25) for isolate 3-DH2 against Aug-E, AM, To, Crm, Cl, and Fd. The AMR genes AAC(6′)-Ic, aac(6′)-Ic_1, aac(6′)-Ial, H-NS, SRT-2, oqxB, oqxB_1, oqxB25, mexI, CRP, and blaSST-1, and flgH, fliP, fliM, and fliG VF genes were identified in the whole genome of the S. marcescens sequenced isolates 1-DH1, 2-DH1, and 4-DH3. In addition, a phylogenomic analysis of these three isolates revealed that WGS genomes are more closely related to S. marcescens prevenient from environmental sources. Conclusions: This study reports, for the first time, AMR resistance to tobramycin, cefuroxime, colistin, and nitrofurantoin in BM S. marcescens isolates. Genomic analysis revealed the presence of multiple AMR and VF genes, further highlighting the pathogenic potential of these isolates. Phylogenomic analysis revealed that the genome of the three BM S. marcescens isolates is more closely related to environmental S. marcescens strains. Full article

The development of sustainable food systems requires the appraisal of novel methods of maintaining soil nutrients and the evaluation of alternative crops and sward systems. Accordingly, this study examined how agricultural hemp responded to an organic fertiliser produced from black soldier fly (BSF; Hermetia illucens) frass. The results indicate that at equivalent N-rates (approx. 0.16 g N per pot), a commercial BSF frass fertiliser (“HexaFrass”) produced similar increases in shoot growth of monoecious and dioecious hemp seedlings as was achieved with established organic fertilisers (chicken manure; Miracle-gro). In one cultivar, CFX-2, it was shown that positive effects on shoot growth could be achieved at low fertiliser rates (≤4 g per pot), and additional fertiliser dd not induce additional shoot growth. Application of HexaFrass increased the shoot content of P, K, and Mg but not N, an important consideration if hemp straw and foliage are to be used as livestock feed. Insect frass fertilisers can supply hemp seedlings with the nutrients required for accelerated shoot growth, but further work is needed to evaluate different fertiliser regimes (e.g., split application; liquid extracts) and to assess how frass fertilisers affect yield and chemical profiles of hemp seeds. Full article

This study investigates the influence of geometric parameters of a gyroid lattice structure on the thermal performance of internal cooling channels relevant to gas turbine blade design. Various gyroid configurations were analyzed using CFD simulations in ANSYS CFX to evaluate heat transfer effectiveness (Nusselt number), cooling flow penetration depth (cooling depth coefficient), and aerodynamic losses (pressure drop and drag coefficient). A series of simulations were conducted, varying lattice wall thickness, structure period, and Reynolds number, followed by the development of regression models to identify key trends. Experimental verification was carried out using 3D printed samples tested on a specially assembled aerodynamic test rig. Results confirmed the existence of an optimal lattice density, providing a favorable balance between heat transfer and pressure losses. The study highlights the high potential of gyroid TPMS structures for turbine blade cooling systems, where additive manufacturing enables complex internal geometries unattainable by traditional methods. The research demonstrates the practical feasibility and thermo-hydraulic advantages of lattice-based cooling channels and provides accurate predictive models for further optimization of turbine blade designs under high-temperature turbomachinery conditions. Full article

This report examined a design solution for a wastewater treatment facility in which—based on input data such as the amount of suspension at the inlet—the solid content in the suspension and sludge, the relative weight of the particles, the sedimentation rate, the diameter and height of the radial settler were determined. After determining the parameters, the design solution was created in the SolidWorks 2024 environment. In the design process, the shape of the fastening device was modified, which is of significant importance in the design of the facility, as it affects in a specific way the concentration of suspended substances in the thickened sludge and in the recirculated sludge flow. The design was transferred into the ANSYS CFX 2017 software for subsequent simulation of its purification function. Based on techniques in fluid mechanics, the boundary and end conditions for the analysis of the fluid flow were set. The study focused on the analysis of a CFD model to describe the movement of a two-phase fluid consisting of rainwater and sand with a particle size of 1–10 mm. Based on the analysis, the results of the influence of rotating elements on the movement of the solid phase and water in the fluid domain were reported. Full article

Indirect evaporative coolers (IECs) are becoming a viable alternative to the more energy-intensive traditional HVAC systems for space cooling, especially in arid regions. In this work, a recently developed computational model of an IEC was used to conduct a parametric study. The model employs a spray dryer model to track the flow path and evaporation rate of droplets. The key parameters investigated were the temperature of the droplets, a bypass effect where the amount of exhaust air and water was reduced to as low as 10%, and the length of the heat exchanger. The results suggest that the wet bulb efficiency could be increased from the previously observed 35% to 72.5% if the water temperature is decreased to 16 °C. In order to drastically increase the performance, the heat exchanger length should be increased from 50 cm to 100 cm, which could still end up in a more compact design overall as fewer plates are required. The bypass study resulted in peak performance when 40% of the secondary air flow was used as working air in conjunction with a proportional reduction in water usage. Overall, the computational model has been employed in an attempt to reduce the bulkiness, increase the efficiency and reduce the water consumption of such a system. Full article

Lithium/carbon fluoride (Li/CF_x) batteries are promising for specialized applications due to their high theoretical capacity (>865 mAh·g⁻¹) and energy density. However, their practical deployment is hindered by the intrinsically low conductivity of CF_x and sluggish reaction kinetics. While conventional conductive additives improve electron transport, their physical mixing with active materials yields weak interfacial contacts and fails to catalytically facilitate C–F bond cleavage. To address these dual limitations, this study proposes a dual-functional conductive-catalytic additive strategy. We engineered zinc-nickel/carbon nanotube (ZnNi/CNT) composites modified with transition metal dopants (Fe, W, Cu) to integrate conductive networks with nanoscale-dispersed catalytic sites. Fe-doped ZnNi/CNT (ZnFeNiC) emerged as the optimal system, delivering a discharge plateau of 2.45 V and a specific capacity of 810.3 mAh·g⁻¹ at 0.1 C. This performance is attributed to Fe-doping accelerates Li⁺ diffusion, and promotes reversible Ni redox transitions (Ni²⁺↔Ni⁰) that catalyze C–F bond dissociation. This work establishes a design paradigm for high-performance Li/CF_x batteries, bridging the gap between conductive enhancement and catalytic activation. Full article

The extended operation of high-speed railways has led to an increased incidence of tunnel lining defects, with falling debris posing a significant safety threat. Within tunnels, single-train passage and trains-crossing events constitute the most frequent operational scenarios, both generating extreme aerodynamic environments that alter debris trajectories from free fall. To systematically investigate the aerodynamic differences and underlying mechanisms governing falling debris behavior under these two distinct conditions, a three-dimensional computational fluid dynamics (CFD) model (debris–air–tunnel–train) was developed using an improved delayed detached eddy simulation (IDDES) turbulence model. Comparative analyses focused on the translational and rotational motions as well as the aerodynamic load coefficients of the debris in both single-train and trains-crossing scenarios. The mechanisms driving the changes in debris aerodynamic behavior are elucidated. Findings reveal that under single-train operation, falling debris travels a greater distance compared with trains-crossing conditions. Specifically, at train speeds ranging from 250–350 km/h, the average flight distances of falling debris in the X and Z directions under single-train conditions surpass those under trains crossing conditions by 10.3 and 5.5 times, respectively. At a train speed of 300 km/h, the impulse of C_Fx and C_Fz under single-train conditions is 8.6 and 4.5 times greater than under trains-crossing conditions, consequently leading to the observed reduction in flight distance. Under the conditions of trains crossing, the falling debris is situated between the two trains, and although the wind speed is low, the flow field exhibits instability. This is the primary factor contributing to the reduced flight distance of the falling debris. However, it also leads to more pronounced trajectory deviations and increased speed fluctuations under intersection conditions. The relative velocity (CRV) on the falling debris surface is diminished, resulting in smaller-scale vortex structures that are more numerous. Consequently, the aerodynamic load coefficient is reduced, while the fluctuation range experiences an increase. Full article

The XPO1 (exportin 1) gene encodes exportin 1 protein responsible for transporting proteins and RNA from the nucleus to the cytoplasm. It has been used as a biomarker for lymphoma detection. XPO1^E571K mutation has been frequently observed and identified as a good prognostic indicator for lymphoma patients. The detection of a target molecule released by lymphoma cells into blood circulation (cell-free circulating tumor DNA, cfDNA) is a better method than tissue biopsy. However, cfDNA concentration in blood circulation is very low in cancer patients. Therefore, a precise and sensitive method is needed. In this study, cfDNA was extracted, and then the XPO1 gene was detected and amplified using conventional PCR. Sanger sequencing was employed to verify the DNA sequences. FAST-COLD-PCR was developed to detect XPO1^E571K gene mutation using a CFX96 Touch Real-Time PCR System. The optimal critical temperature (Tc) was 73.3 °C, allowing selective amplification of XPO1^E571K mutant DNA while wild-type XPO1 could not be amplified. XPO1^E571K gene mutation can be detected by this method with high specificity and sensitivity in lymphoma patients. This approach facilitates rapid and straightforward detection in a timely manner after the diagnosis. Accordingly, the optimized FAST-COLD-PCR conditions can be used as a prototype for XPO1^E571K mutant detection in lymphoma patients. Full article

Implementing energy-efficient solutions and developing energy complexes to decentralise power supply are key objectives for enhancing national security in Ukraine and Eastern Europe. This study compares the design, numerical, and experimental parameters of a channel-type jet-reaction turbine. A steam turbogenerator unit and a pilot industrial experimental test bench were developed to conduct full-scale testing of the unit. The article presents experimental data on the operation of a steam turbogenerator unit with a capacity of up to 475 kW, based on a channel-type steam jet-reaction turbine (JRT), and includes the validation of a computational fluid dynamics (CFD) model against the obtained results. For testing, a pilot-scale experimental facility and a turbogenerator were developed. The turbogenerator consists of two parallel-mounted JRTs operating on a single electric generator. During experimental testing, the system achieved an electrical output power of 404 kW at a turbine rotor speed of 25,000 rpm. Numerical modelling of the steam flow in the flow path of the jet-reaction turbine was performed using ANSYS CFX 25 R1 software. The geometry and mesh setup were described, boundary conditions were defined, and computational calculations were performed. The experimental results were compared with those obtained from numerical simulations. In particular, the discrepancy in the determination of the power and torque on the shaft of the jet-reaction turbine between the numerical and full-scale experimental results was 1.6%, and the discrepancy in determining the mass flow rate of steam at the turbine inlet was 1.34%. JRTs show strong potential for the development of energy-efficient, low-power turbogenerators. The research results confirm the feasibility of using such units for decentralised energy supply and recovering secondary energy resources. This contributes to improved energy security, reduces environmental impact, and supports sustainable development goals. Full article

Efficient water heating is essential for wool-washing processes, which demand temperatures above 70 °C. To meet this requirement sustainably, a parabolic trough solar concentrator system is proposed in this paper as an alternative to conventional natural gas systems. The design centers on a water pool constructed from bricks reinforced with an internal steel layer, enhancing heat exchange efficiency. Also, various synthetic oils were analyzed as heat transfer fluids (HTFs) within an immersed heat exchanger, such as Thermia B oil, Heat Transfer Oil 32, biphasic oil, and Therminol vp1 oil. Numerical simulations were performed using ANSYS CFX v19.2 software with the k-ε turbulence model to evaluate the thermal performance and temperature distribution. The results demonstrate the superior efficiency of the solar-powered system, with the steel-reinforced pool achieving optimal water temperatures between 78 °C and 85 °C, exceeding the required threshold for industrial wool washing. Among the various synthetic oils analyzed, Thermia B emerged as the most effective heat transfer fluid, maintaining water temperatures in the range of 75 °C to 85 °C. This superior thermal performance is attributed to its high thermal conductivity and reduced heat loss, ensuring consistent and optimal heat distribution for the wool-washing process. Full article

The ongoing efforts to convert High-Performance Research Reactors (HPRRs) using Highly Enriched Uranium (HEU) to Low-Enriched Uranium (LEU) fuel require reliable thermal–hydraulic assessments of modified core designs. The involute-shaped fuel plates used in several major HPRRs present unique modeling challenges due to their compact core geometries and high heat flux conditions. This study evaluates the capability of three commercial CFD tools, STAR-CCM+, COMSOL, and ANSYS CFX, to predict cladding-to-coolant heat transfer using Reynolds-Averaged Navier–Stokes (RANS) methods within the thermal–hydraulic regimes of involute-shaped plate reactors. Broad sensitivity analysis was conducted across a range of reactor-relevant parameters using two turbulence models ($k-ϵ$ and $k-\omega$ SST) and different near-wall treatment strategies. The results were benchmarked against the Sieder–Tate correlation and experimental data from historic studies. The codes produced consistent results, showing good agreement with the empirical correlation of Sieder–Tate and the experimental measurements. The findings support the use of these commercial CFD codes as effective tools for assessing the thermal–hydraulic performance of involute-shaped plate HPRRs and guide future LEU core development. Full article

Model validation is an essential part of CFD-based projects. Despite being successfully employed for decades, the level and extent of CFD model validation details vary significantly in the published literature, which, in turn, adversely affects the repeatability and usefulness of published models and data. This study explores the various challenges associated with validating CFD models of thermodynamic components, namely, the compressors and their performance evaluation. The methodology involves blade generation through TurboGrid and BladeGen, mesh generation to ensure computational efficiency, and pre-processing with CFX to define boundary conditions and turbulence models, all within ANSYS 2024 R1. Three case studies are discussed, each assessing different compressor configurations and common challenges encountered during the model validation stage. Based on the case studies, a number of recommendations are presented relating to best practices in terms of both the use of published materials to validate new models and the level of detail required for experimental or simulation publication to ensure they can be replicated or used to validate a new model. Full article