Search Results (45)

Airfoil fin Printed Circuit Heat Exchangers (PCHEs) offer significant advantages in reducing flow resistance, promoting turbulence, and enhancing heat transfer performance due to their discrete fin configuration. However, compared with conventional continuous-channel structures, the geometric discontinuities and sharp trailing edges introduced by discrete fins tend to induce severe stress concentration at the fin roots, resulting in a more complex structural response. In this study, a PCHE core with NACA0020 airfoil fins is investigated. Finite element analysis combined with a sequential one-way thermo-structural coupling approach is conducted to characterize the fins’ stress and deformation behavior under high temperature and pressure. The plate region is evaluated based on the linear elastic stress criteria specified in ASME Boiler and Pressure Vessel Code Section III, while localized yielding regions such as the fin roots are assessed using an equivalent plastic strain indicator. Results indicate that the structural response of the PCHE core is dominated by pressure loading under the investigated operating conditions with ΔT = 18 °C and ΔP = 12.05 MPa, whereas thermal stress caused by constrained thermal expansion mainly modifies local stress distributions and has a limited effect on global deformation. Owing to the discontinuous support provided by discrete airfoil fins, the fin roots act as the primary load-transfer path and sustain higher stress levels. The maximum von Mises stress is observed at the trailing edge of the fin root on the high-pressure side, while the largest deformation occurs in the unsupported plate region and is governed by bending. Parametric analysis indicates that, within the investigated parameter range, a fully staggered fin arrangement promotes more uniform load distribution and exhibits the most favorable structural response. In contrast, increasing the fin chord length and relative thickness reduces the overall load-carrying capacity of the core. Finally, a power-law predictive correlation for the maximum total plate deformation was developed, showing that the parameter influence on plate structural response follows the order horizontal pitch (L_h) > vertical pitch (L_v) > channel etching depth (L_e) > staggered pitch (L_s). In contrast, normalized sensitivity analysis of the maximum fin-root von Mises stress shows the order staggered pitch (L_s) > horizontal pitch (L_h) > vertical pitch (L_v) > channel etching depth (L_e), indicating that global plate deformation and local fin-root response are governed by different structural mechanisms. Full article

This paper presents a high-performance and resource-efficient Field Programmable Gate Array (FPGA)-based architecture for satellite telemetry transmission systems. The proposed design implements a flexible channel coding chain, including Reed–Solomon (R-S) encoding, convolutional encoding, symbol interleaving, pseudo-randomization, and Attached Synchronization Marker (ASM) insertion, in accordance with CCSDS recommendations. The architecture is fully integrated and configurable, allowing dynamic selection of coding schemes without requiring structural modifications. The system is implemented on a modern FPGA platform with a 32-bit AXI4-Stream interface at 110 MHz, reaching an effective throughput of up to 1.76 Gbps. Experimental results demonstrate reliable timing with positive setup and hold margins, allowing the system to operate at approximately 130 MHz. Power consumption is measured using Switching Activity Interchange Format (SAIF)-based switching activity, providing a realistic estimate of programmable logic power consumption. The total on-chip power is about 1.77 W for individual coding modes. It rises to 1.91 W in the concatenated setup, which is the worst-case scenario. The results show that the proposed architecture efficiently uses resources, runs reliably at high speeds, and exhibits predictable power consumption. This makes it well suited for high-reliability and energy-constrained satellite communication systems. resources are used. Full article

Qualification is the evidence-based process through which confidence is established that a component will perform its intended function, in its intended environment, for its intended lifetime, with the required reliability. It is an owner-led activity that defines the type, quantity and quality of data required for codification and for the industrial deployment of components and their structural materials. This paper presents a structured qualification framework and applies it to a fusion machine breeder blanket structure as a representative component. It demonstrates that qualification, rather than material properties alone, dictates the use of fusion structural materials and the deployment of such materials under ASME BPV and AFCEN RCC codes. Current limitations in addressing irradiation synergy, liquid metal corrosion, and joint integrity expose gaps that these codes cannot yet prescribe. Two contrasting structural blanket material case studies: metallic-based ferritic-martensitic steel Eurofer97 and non-metallic-based silicon carbide fibre-reinforced composites (SiC_f/SiC) are used to illustrate the differing evidence requirements for each system type. Industrial scale-up considerations, including alloy specifications, manufacturing readiness, inspection reliability, and supply-chain maturity, are evaluated alongside the need for internationally harmonised datasets and design methodologies. Fusion programmes can use a phased qualification strategy in which early, time-limited operation under controlled conditions builds the evidence needed for codification and scale-up, with the required pre-operation qualification level depending on risk, component criticality and failure consequences, and with the pace of qualification ultimately setting how quickly industry can supply components for commercial fusion. Codification remains essential for commercial deployment because construction codes express codified material behaviour through allowable stresses and permitted fabrication routes, enabling designers to use advanced materials without disclosing proprietary data. In jurisdictions where ASME BPV compliance is mandatory, codification determines whether a material may enter pressure boundary service and must therefore form part of the fusion machine owner’s long-term strategy for deployment. Full article

The fatigue behaviour of a 90° long radius elbow, which is adjacent to the feedwater nozzle in a BWR, was analyzed. The start-up and shutdown transients were considered. A thermo-mechanical finite element analysis was carried out to determine the stresses induced by thermal transients, considering the environmental conditions in the reactor feedwater pipe. In addition, the Palmgren–Miner methodology and the ASME B&PVC code fatigue curve were applied to evaluate the accumulated damage and service life of the component. Environmental correction factors were considered to estimate environmentally assisted fatigue. Reductions in fatigue life were observed. In the second part of this paper, a part-through thickness semielliptical crack was also postulated in the internal surface of the elbow. It was aligned along the axial direction at the crown zone. Its growth was modelled using the Paris equation, evaluating the risk of failure using fracture parameters. It was found that the vulnerable area is located on the inner surface of the elbow, due to the concentration of stress caused by the curved geometry. Failure assessment diagrams (FADs) were plotted. It was found that the crack depth is the main factor governing crack behaviour under the conditions studied. The results provide a methodology for assessing the integrity of pipes subjected to specific environmental and operating conditions. Full article

In contemporary communication systems, digital images occupy an irreplaceable role; however, the privacy-related risks attendant to their prevalent application have grown increasingly salient. This paper presents an image encryption scheme integrating a novel two-dimensional Ackley-Sine chaotic map (2D-ASM) with dynamic DNA operations. First, a two-dimensional Ackley-Sine chaotic map, constructed based on the Ackley function and sine function, is designed and validated through a series of chaotic indicators. Results demonstrate that 2D-ASM exhibits superior chaotic properties compared to several existing state-of-the-art chaotic maps, with its maximum Lyapunov exponent (LE) exceeding 23, Permutation Entropy (PE) close to 1 in the full parameter range, and correlation dimension (CD) significantly higher than comparative chaotic systems. The proposed 2D-ASM-based image encryption scheme leverages the SHA-256 hash value of the plaintext image and four external keys to jointly generate the initial conditions and parameters of the 2D-ASM chaotic system, thereby ensuring a sufficiently large key space of 2²⁵⁶. Subsequently, chaotic sequences generated by 2D-ASM are employed to permute and diffuse the plaintext image, followed by dynamic DNA coding, operations, and decoding to obtain the encrypted image. Security analyses and comparisons with several existing representative algorithms confirm that the proposed encryption scheme achieves excellent encryption performance: the Number of Pixels Change Rate (NPCR) is above 99.6%, the Unified Average Changing Intensity (UACI) approaches 33.4%, and the information entropy of ciphertext images reaches 7.999 or higher. The scheme can effectively resist various potential attacks, including statistical and differential attacks, and outperforms representative algorithms in pixel correlation reduction and anti-interference performance. Full article

Weld root reinforcement is a critical geometric parameter governing stress concentration and structural performance in thin-walled stainless-steel piping systems designed to ASME B31.3. While current codes specify permissible dimensional limits, they do not explicitly quantify how incremental variations in root height influence stress distribution under realistic service loading conditions. This study integrates finite element analysis (FEA) with experimentally validated GTAW weld profiles to evaluate the structural influence of weld root height in 316L stainless-steel pipe joints. An experimentally manufactured 4 in schedule 10S joint with a measured root height of less than 1.5 mm was adopted as the baseline geometry. Additional models with reinforcement heights of 1.138, 2.0, 2.5, and 3.0 mm were evaluated under two representative load cases: (i) internal pressure combined with drag and axial thrust (LC-1), and (ii) internal pressure with thrust only (LC-2). The results demonstrate that reinforcement heights exceeding 2.0 mm increase von Mises, hoop, longitudinal, and radial stress gradients, with peak stresses shifting toward the weld toe under drag-inclusive loading. In contrast, reinforcement ≤2 mm provides smoother load transfer and reduced stiffness discontinuity across the weld interface. The combined numerical and experimental findings support a stress-informed upper limit of 2 mm for weld root reinforcement in thin-walled stainless-steel pipelines, offering a performance-based complement to existing dimensional acceptance criteria. Full article

Fatigue properties of low-alloy steels, LAS, are well defined in air and at the beginning of life. However, the potential influence from thermal ageing under conditions relevant for the nuclear industry is uncertain. In this study, the fatigue properties of LAS base and weld metals, aged at 345 °C for 215,000 h, are compared to as-delivered archive reference materials. In the weld material, ageing appears as an increase in yield and ultimate tensile strength. Ageing also manifests as an inclined strain–cycle (ε-N) fatigue curve, where fatigue life decreases in the low-cycle fatigue region and conversely increases in the high-cycle fatigue region. The results further show that both as-delivered and aged weld metals exhibit a significantly shorter fatigue life in the low-cycle fatigue region and a longer fatigue life in the high-cycle fatigue region when compared to the ASME Code best-fit curve. Full article

The global shift towards cleaner energy has accelerated the application of hydrogen as a clean fuel. Retrofitting and reusing existing natural gas (NG) pipeline infrastructure is a cost-effective way to enable bulk deployment of hydrogen. This study investigates the technical feasibility of retrofitting and rehabilitating NG pipelines for hydrogen transport. Material compatibility, especially hydrogen embrittlement, fatigue resistance, and permeability in steel pipes and weld joints, is examined in the analysis. Retrofitting approaches such as internal coatings, flow regulation, and pipeline pressure adjustments are reviewed in the context of current engineering standards. Structural integrity assessments, using established codes, are conducted to evaluate post-retrofit performance and safety. This is a literature-based technical assessment using existing codes and standards, such as CSA Z662 and ASME B31.12, combined with industry case studies and experimental insights to evaluate the readiness of legacy pipelines for hydrogen service. This paper provides a foundational framework for assessing the safe reuse of legacy pipeline systems for pure or blended hydrogen transport. It sets the stage for further techno-economic analysis in future research. Full article

Fiber-reinforced polymer (FRP) pipes are increasingly used in pressure piping systems due to their corrosion resistance and favorable mechanical performance; however, the direct experimental validation of design assumptions adopted in international standards remains limited. The objective of this study is to experimentally validate the mechanical response and stress distribution of filament-wound GFRP pipes under representative loading conditions and to assess the consistency of the measured behavior with the allowable-stress design framework of ISO 14692 and complementary ASME and BS codes. In this study, the mechanical behavior of filament-wound glass fiber-reinforced polymer (GFRP) pipes is investigated through a combined experimental program including tensile, bending, and full-scale internal pressure tests. Electrical resistance strain gauges were applied in axial and circumferential directions to directly measure deformation under internal pressure up to 31 bar, allowing experimental stresses to be derived using orthotropic laminate relationships. The results demonstrate a predominantly linear elastic response within the service range, followed by progressive damage initiation at higher load levels, with circumferential stresses consistently exceeding axial stresses, confirming a hoop-dominated response. At the maximum applied pressure of 31 bar, axial and circumferential strains reached approximately ε_a ≈ 1.30 × 10⁻³ and ε_h ≈ 1.60 × 10⁻³, corresponding to experimentally derived stresses of σ_a^exp ≈ 15.3 MPa and σ_h^exp ≈ 18.8 MPa, without catastrophic failure. The novelty of this work lies in the direct integration of full-scale strain gauge measurements with standardized allowable-stress design assumptions, enabling an experimental validation of ISO 14692 that is rarely addressed in existing studies. The experimentally derived stress–strain data show good agreement with theoretical models and provide a direct link between measured behavior and the allowable stress philosophy and design equations defined in ISO 14692 and complementary ASME and BS design codes. The findings validate the applicability of standardized design approaches and provide experimentally grounded support for engineering design decisions in FRP piping systems. Full article

The partial secondary stress (hereinafter referred to as secondary mechanical membrane stress $Q_L$) generated by structural discontinuity effects is not considered by the current codes and standards and will lead to conservatism in stress analysis results. Two methods, called the translation method and the noncyclic method, are used in this paper to deduce the modified Bree ratcheting boundaries after separating $Q_L$ and it presents the calculation formulas for the intersection coordinates between the modified Bree ratcheting boundaries and the corresponding modified 3S lines. Based on the modified elastic shakedown boundaries, two complete and feasible criteria for elastic ratcheting assessment are put forward, aiming to solve the unconservative issue of the 3S criterion when $P_{\mathrm{L}}$ exists and the problem of excessive conservatism in assessment at structural discontinuities. Finally, a universal elastic stress ratcheting assessment method considering $Q_L$ is proposed by integrating elastic ratcheting analysis, thermal stress ratcheting assessment, and simplified elastic–plastic analysis in ASME VIII-2, which significantly improves the economy and operability of the design at structural discontinuities. Full article

Malicious software presents significant challenges in cybersecurity, leveraging rapidly evolving technologies to bypass traditional defense mechanisms. This research introduces a novel image-based malware classification framework that uses hybrid-model Convolutional Neural Networks to process RGB images generated from assembly code. We present MalevisAsm, an enriched dataset that merges MaleVis malware samples with benign files, and propose a hybrid deep learning model that combines EfficientNetB0 and DenseNet121 for robust feature extraction. The approach transforms Portable Executable files into assembly code, maps opcode transitions into three-channel images, and uses a fine-tuned CNN to classify malware families. Additionally, we implemented Uniform Manifold Approximation and Projection a contemporary nonlinear dimensionality reduction technique, to enhance the identification of previously unseen malware samples via binary classification. Our experiments achieve a top-tier accuracy of 98.45%, surpassing existing benchmarks on the MaleVis dataset. This research contributes to the field by integrating static binary analysis with advanced computer vision techniques, offering a scalable and effective solution for malware detection. Full article

Background: This research aims to enhance the genomic database of Klebsiella oxytoca by identifying virulence genes through the whole genome sequencing and comparative analysis of a goat-derived K. oxytoca (KOHN1) strain, while clarifying the relationship between its genetic evolution and virulence, ultimately providing a theoretical foundation for clinical prevention and diagnosis. Methods: Third-generation Oxford Nanopore Technologies (ONT) sequencing and second-generation Illumina sequencing were used to sequence the strain and analyze the database annotations. Screening for 10 virulence genes was conducted using PCR. Comparative genomic analyses of the strain KOHN1 with four human-derived K. oxytoca model strains were performed using collinearity analysis, taxonomy classification through ANI analysis, and gene function family analysis. Results: The genome size of the KOHN1 strain was 5,817,806 bp, and the GC content was 55.14%. It contained 5227 predicted coding genes, including 25 rRNA genes, 85 tRNA genes, and 53 sRNA genes. A total of 14 type VI secretion system effector proteins and 146 virulence factor-related genes were annotated. Additionally, eight virulence genes—fimA, fimH, entB, mrkD, clpV, rmpA, vgrG, and hcp—were detected through PCR identification. The strain has 448 drug resistance genes, mainly against β-lactams and fosfomycins. Comparative genomic analysis indicated that its closest relation is the human isolate ASM338647. Conclusions: In this study, the whole genome sequence of a goat-derived K. oxytoca (KOHN1) strain was obtained, revealing its evolutionary relationship with domestic and foreign isolates and providing a reference for future studies on the mechanisms of antimicrobial resistance and the pathogenicity of K. oxytoca. Full article

One of the challenges in the current reactor is the gap between the outlet nozzle of the Reactor Vessel (RV) and the outlet opening of the Core Support Barrel (CSB). This gap causes bypass flow, reducing the overall efficiency. To address this issue, RV and CSB designs were modified with various configurations. Through finite element analysis, this study evaluated the structural integrity and dynamic response of an RV and CSB with these modified designs. The structural integrity was assessed against ASME code to determine the limits of design parameter changes that met code requirements. Additionally, the natural vibration characteristics of the CSB and RV were analyzed to evaluate improvements in the seismic response by modal analysis. The findings revealed that the CSB design in the case of 3-degree slanted contact with the RV outlet nozzle provided the most optimized results. Moreover, modal analysis indicated a substantial enhancement in seismic response, with the dominant CSB mode frequencies increasing by 30%. This shift, from the 15–20 Hz range to the 20–30 Hz range, is especially noteworthy given the concentration of seismic energy within the 1–20 Hz band. Full article

Pesticide-free agriculture is a fundamental pillar of environmentally friendly agriculture. To this end, there is an active search for new bacterial strains capable of synthesizing secondary metabolites and toxins that protect crops from pathogens and pests. In this study, we isolated a novel strain d21.2 of Peribacillus frigoritolerans from a soil sample collected in the Republic of Dagestan, Russia. Leveraging several bioinformatic approaches on Illumina-based whole-genome assembly, we revealed that the strain harbors certain insecticidal loci (coding for putative homologs of Bmp and Vpa) and also contains multiple BGCs (biosynthetic gene clusters), including paeninodin, koranimine, schizokinen, and fengycin. In total, 21 BGCs were predicted as synthesizing metabolites with bactericidal and/or fungicidal effects. Importantly, by applying a re-scaffolding pipeline, we managed to robustly predict MGEs (mobile genetic elements) associated with BGCs, implying high genetic plasticity. In addition, the d21.2’s genome was free from genes encoding for enteric toxins, implying its safety in use. A comparison with available genomes of the Peribacillus frigoritolerans strain revealed that the strain described here contains more functionally important loci than other members of the species. Therefore, strain d21.2 holds potential for use in agriculture due to the probable manifestation of bactericidal, fungicidal, growth-stimulating, and other useful properties. The assembled genome is available in the NCBI GeneBank under ASM4106054v1. Full article

Brazil’s Forest Code (FC) is a landmark law that, despite dating back to the 1930s, has low compliance. Illegal deforestation continues, and millions of hectares that were set to be reforested remain degraded. Although sector agreements such as the Amazon Soy Moratorium (ASM) have been important in the fight against deforestation, the implementation of the FC represents the key long-term strategy to halt deforestation in the soy supply chain. Here, we used datasets of the boundaries of rural properties, deforestation permits, environmental licensing, and land cover in Mato Grosso to quantify illegal deforestation and analyzed compliance with the Forest Code (FC) on soy farms to explore how loopholes in the implementation of the FC allow deforestation to continue unabated. Our analyses show that between August 2009 and July 2019, soy farms in Mato Grosso State, the largest Brazilian soy producer, were responsible for 15% (or 468.1 thousand hectares) of all land cleared in registered properties. Half of this deforestation was illegal. The FC implementation within these properties has been slow: only 11% of registered soy farms have made it to the final stage of the registration process, thus being considered fully compliant. This novel analysis reinforces that accelerating the implementation of the FC could significantly reduce deforestation and advance the restoration of illegally cleared land particularly in the Cerrado, where 50% of the original cover has already been lost, as well as in the Amazon. By achieving full compliance in the soy sector, Brazil’s position in the international market would be strengthened as a supplier of sustainably produced, deforestation-free commodities. Full article