Search Results (41)

Division (DIV), reciprocal (REC), square root (SR), and reciprocal square root (RSR) are fundamental operations in digital signal processing (DSP), communication, and matrix decomposition applications. However, implementing these functions using dedicated hardware units increases area and resource utilization when multiple operations are required within the same system. This paper presents a multifunctional fixed-point architecture that supports DIV, REC, SR, and RSR operations within a unified Newton–Raphson-based framework. The proposed design employs scaling and de-scaling techniques to facilitate architectural parameterization across generic fixed-point formats, piecewise polynomial approximations for seed generation, and hardware sharing between the seed computation and Newton–Raphson stages to enhance overall computational efficiency. The architecture was described in Verilog–HDL and evaluated through FPGA and ASIC implementation flows. To demonstrate the feasibility of the design, the experimental validation and implementation scope were focused on a specific of 16 bits word-length. FPGA synthesis results show that the proposed multifunctional unit achieves operating frequencies comparable to dedicated implementations while reducing hardware cost by approximately 40% compared with separate arithmetic units. Exhaustive simulations using a 16-bits representation yield SQNR values ranging from 72.03 dB to 81.03 dB across the supported operations. Furthermore, ASIC implementation using an Intel 16 nm PDK confirms the feasibility of the proposed approach for advanced technology nodes under the verified format. These results demonstrate that the proposed architecture provides an effective trade-off among accuracy, latency, and hardware efficiency, making it well suited for high-performance fixed-point DSP accelerators. Full article

Teeth may retain forensic value after chemical exposure, yet the effects of commercially available corrosive agents remain insufficiently characterized. This study evaluated short-term alteration patterns in human teeth exposed to household acidic and alkaline products available on the Romanian market. Five extracted mandibular third molars were analyzed, including four experimental teeth and one control. Each experimental tooth was fully immersed for 48 h in a different agent: hydrochloric acid descaler, sodium hypochlorite bleach, mixed hydrochloric/sulfuric acid descaler, or sodium hydroxide. Morphometric changes, mass, and pH were monitored serially, while stereomicroscopy, SEM-EDX, and hard tissue ground sections were used for structural and compositional assessment. Acid-exposed teeth showed the greatest damage, with major mass loss in the hydrochloric acid and mixed-acid samples, enamel loss, and marked microstructural disruption. The mixed-acid specimen exhibited the most severe collapse and near-complete calcium/phosphorus depletion. Sodium hypochlorite produced mainly superficial and root-level alterations with relative preservation of gross morphology, whereas sodium hydroxide caused minimal dimensional change and a calcium-rich adherent surface deposit. These findings show that household corrosives produce distinct, forensically recognizable dental alteration patterns within 48 h and support an integrated pattern-recognition approach in suspected chemical concealment scenarios. Full article

In this study, a three-dimensional simulation of a walking-beam reheating furnace was developed to improve the steel slab reheating process and reduce surface oxidation kinetics using computational fluid dynamics (CFD). Combustion, heat transfer, fluid dynamics, and chemical reaction models were integrated into the numerical framework of this study. In addition, dynamic mesh remeshing was coupled through user-defined functions (UDFs), enabling the simultaneous simulation of slab movement and evolution of the involved transport phenomena. Turbulence was modeled with the realizable k-ε formulation, combustion with the Eddy Dissipation model, and radiation with the P-1 model coupled with WSGGM to include CO₂ and H₂O gas radiation. Scale formation was modeled using customized functions based on Arrhenius-type kinetics and Wagner’s oxidation model, evaluating its growth as a function of time, temperature, and furnace atmosphere. The predicted thermal evolution inside the furnace was validated using industrial data, yielding an average deviation of 5%. Furthermore, the proposed operating conditions led to an average slab temperature of 1289.77 °C at the exit of the homogenization zone, which was 16 °C higher than that under the current operation but still within the target range (1250 ± 50 °C). The reduction in combustion air decreased energy losses and improved product quality, lowering the molar oxygen content in the furnace atmosphere from 4.9 × 10² mol to 6.7 × 10¹ mol. Additionally, annual savings of 4,793,472 kg of natural gas and 13,884 tons of steel were estimated owing to reduced oxidation losses. The proposed air–fuel adjustment led to estimated annual energy savings (equivalent to 4,793,472 kg of natural gas) and a reduction in material loss due to oxidation from 4.5% to 3.75% (an absolute reduction of 0.75 percentage points; relative reduction ≈ 16.7%), which has a significant industrial impact on metal conservation and descaling cost reduction. Although there are CFD studies on plate overheating and scale growth separately, this work presents three main contributions: (1) the integration, within a single numerical framework, of combustion, radiation, species transport, oxidation kinetics, and actual plate movement using a dynamic mesh; (2) validation against continuous industrial records (16 thermocouples) and quantification of operational benefits such as fuel savings and reduced material loss; and (3) a comparative analysis between actual and optimized conditions, which standardize the air–methane ratio. Full article

Conveyance tube manufacturing via a hot-finished, welded route is an energy-intensive process that promotes the rapid surface oxidation of curved surfaces. Previous studies have used computational and theoretical techniques to assess the oxidation of curved surfaces. However, experimental techniques for assessing the oxidation of curved surfaces, as well as for validating existing computational and analytical studies, have significant limitations that impact their ability to accurately recreate industrial processes. The challenges of thermogravimetric analysis (TGA) for in situ tests for the oxidation of cylindrical geometries were investigated, using an as-welded conveyance tube, and compared to an equivalent tube normalised in industry as well as computational predictions for the same geometry and thermal conditions. A core element of this work was the use of a refractory dummy sample to quantify thermal buoyancy and flow-induced vibration. There was a strong agreement between the oxide mass gain predicted by a computational model compared to that of the TGA sample, with only a 5% discrepancy. However, oxide thickness gain, measured using electron microscopy, showed poor agreement, particularly when comparing industrial and experimental results. This was attributed to the need for further work to account for transient heating, oxide porosity, atmospheric composition variation, and the effect of thermomechanical operations during conveyance tube manufacturing, e.g., hydraulic descaling. Full article

The present study aimed to analyze the physicochemical properties and biological activity of an L-malic acid descaler. The treated water with L-malic acid descaler complies with EU Directive No. 2020/2184 for the quality of water intended for human consumption. The L-malic acid descaler contains L-malic acid as the active component, while polyethylene and activated charcoal function as structural and absorbent materials, respectively. The composition was analyzed in a licensed laboratory using Chemical Abstracts Service Number (CAS) and European List of Notified Chemical Substances (EINECS) standards. Fourier Transform Infrared (FT-IR) analysis confirmed the presence of hydroxyl (–OH), carbonyl (C=O), and carboxyl (–COOH) groups in L-malic acid descaler, which are connected with proton-donating ability, and redox activity. The biological activity was evaluated using Saccharomyces cerevisiae as a model system. The role of the YAP1 transcription factor, a key regulator of oxidative stress defense mechanisms, was also examined. The detrimental effects on a cellular level were induced by the well-known mutagen—methyl methanesulfonate (MMS). Our data revealed that yeast cells treated with such water decrease the MMS-induced superoxide anions (3.5-fold), total glutathione lipid peroxidation (1.5-fold), and total glutathione (3-fold) and increase cell survival (2-fold). In conclusion, water treated with L-malic acid descaler possesses antioxidant effects in yeast-cell-based tests, independent of YAP1 transcription factor activity. This study provides preliminary evidence that L-malic acid, when dissolved in water, significantly reduced MMS-induced superoxide anions, one of the biomarkers contributing to the genotoxic and carcinogenic effects of MMS. Full article

Modeling hot rolling remains a major challenge in computational solid mechanics. It demands the simultaneous consideration of geometric and material responses. Although the finite element method (FEM) is widely used, multi-pass simulations often treat each pass independently, leading to error accumulation, particularly in flat product rolling, where inter-pass interactions are crucial. Advanced models and remeshing techniques have been developed to address these issues, but substantial computational resources are required. In this study, a previously validated and simplified 3D FEM model was employed to simulate the initial stages of the hot rolling of large-scale AISI 430 ferritic stainless-steel slabs, using data from an industrial rolling schedule. Specifically, the simulations encompassed preheating and descaling, and seven passes of the roughing stage. Through these simulations, a transfer bar with an approximate length of 16,100 mm was obtained. The simulated thickness and rolling load values were compared with experimental data, demonstrating good agreement in most passes. Subsequently, the temperature, effective plastic strain, and equivalent stress distributions along the rolled material were extracted and analyzed. The results highlighted that the employed model adequately predicted the variations in the analyzed parameters throughout the volume of the rolled material during the different stages of the process. However, discrepancies were identified in the rolling load values during the final passes, which were attributed to the presence of phenomena not considered in the constitutive model used. This model will be refined in future studies to reduce the error in the rolling load estimation. Full article

The mechanical properties of surfacing layers are significantly affected by the precipitation and evolution of carbides in nickel-based alloys. At present, the study of carbide precipitation in a Ni-Cr-B-Si surfacing layer is described by using the phase field method. In this paper, the true Gibbs free energy of the M₂₃C₆ carbide phase in Ni-Cr-C ternary alloy was established by the CALPHAD method and thermodynamic database. The growth and coarsening process of M₂₃C₆ carbide was simulated based on phase field method. The microstructure of M₂₃C₆ carbide of Ni-Cr-C alloy at 1373 °C isothermal aging time was observed by scanning electron microscope (SEM). The results show that the growth and coarsening of the precipitated M₂₃C₆ carbide phase are undergone through multiple processes during isothermal aging. First, a single precipitate core is formed, and then the single precipitate continues to coarsen and grow, forming a lamellar structure. Two precipitates contact to form a single rod-like structure, and multiple precipitates form slender rod-like structures. Finally, the contacting elongated rod-like structures grow, forming a typical layered eutectic carbide. The precipitation behavior, growth, and coarsening process of M₂₃C₆-type carbides in Ni-Cr-B-Si series alloys are explored through phase field simulation and experimental research in this paper. A theoretical basis is provided for the rational control and distribution of carbides in surfacing layers. A reference is also offered for optimizing the nickel-based superalloy materials used for surfacing the surface of descaling rolls. Full article

The remote sensing community benefits from new sensors and easier access to Earth Observation data to frequently released new land-cover maps. The propagation of such independent and heterogeneous products offers promising perspectives for various scientific domains and for the implementation and monitoring of land-use policies. Yet, it may also confuse the end-users when it comes to identifying the most appropriate product to address their requirements. Data fusion methods can help to combine competing and/or complementary maps in order to capitalize on their strengths while overcoming their limitations. We assessed the potential of the Dempster–Shafer Theory (DST) to enhance oil palm mapping in Sumatra (Indonesia) by combining four land-cover maps, hereafter named DESCALS, IIASA, XU, and MAPBIOMAS, according to the first author’s name or the research group that published it. The application of DST relied on four steps: (1) a discernment framework, (2) the assignment of mass functions, (3) the DST fusion rule, and (4) the DST decision rule. Our results showed that the DST decision map achieved significantly higher accuracy (Kappa = 0.78) than the most accurate input product (Kappa = 0.724). The best result was reached by considering the probabilities of pixels to belong to the OP class associated with DESCALS map. In addition, the belief (i.e., confidence) and conflict (i.e., uncertainty) maps produced by DST evidenced that industrial plantations were detected with higher confidence than smallholder plantations. Consequently, Kappa values computed locally were lower in areas dominated by smallholder plantations. Combining land-use products with DST contributes to producing state-of-the-art maps and continuous information for enhanced land-cover analysis. Full article

The descaling roll is a critical component in a hot-rolling production line. The operating conditions are significantly impacted by water with high-pressure and dynamic shocks caused by high-temperature steel slab descaling. Roll surfaces often experience wear and corrosion failures. This is attributed to a combination of high temperatures, intense wear, and repeated thermal, mechanical, and fluid stresses. Production costs and efficiency are significantly affected by the replacement of descaling rolls. Practice shows that the use of plasma cladding technology forms high-performance coatings. Conventional metal surface properties can be significantly improved. In this study, a Ni-WC composite coating was prepared on the descaling roll surface by plasma-transferred arc welding (PTAW) technology. The microstructure and phase composition of the welding overlay were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results show that the WC hard phase added to the molten pool dissolves, and subsequently M₇C₃ and W₂C phases are formed. To further explore the morphological evolution mechanism of the hard phase, numerical simulations were performed using a phase-field method to model M₇C₃ phase precipitation. The evolution from nucleation, rod-like growth, to eutectic structure formation was revealed. Experimental and simulation results show high consistency, validating the established phase-field model. In this study, a theoretical foundation for designing and preparing high-performance coatings is provided. Full article

The formation of barium sulfate scale is a persistent and formidable challenge across various industrial processes. In order to effectively mitigate this problem, this study proposed the development of an innovative azacrown ether-based macrocycle descaling agent. Using density functional theory, an in-depth analysis of the surface energy of different barium sulfate crystal facets was carried out, together with a detailed investigation into the adsorption properties of the functional groups on the (001) surface. A further comprehensive investigation was carried out to determine how changes in the nitrogen and oxygen atoms in the crown ether framework influence its adsorption affinity to barium ions. In addition, a detailed analysis was carried out to elucidate the molecular interactions between crown ethers with pyridine carboxylic acid side chains and barium sulfate. The newly developed decalcifying macrocycle descaling agent exhibited superior adsorption performance, achieving an adsorption energy for barium ions approximately −4.1512 ev higher than that of conventional DTPA decalcifiers. This remarkable improvement is mainly attributed to the pivotal role of electrostatic forces in the coordination process between the macrocycle descaling agent and barium ions, with an electrostatic potential value reaching −143.37 kcal/mol. This discovery not only introduces a novel approach to the removal of barium sulfate scale but also highlights the significant potential of macrocycle chemistry in industrial applications. Full article

Electrochemical descaling devices have been widely used in the industrial field due to their broad applicability, convenience of operation, and cost-effectiveness. However, there are many factors that affect the descaling performance of electrochemical descaling devices, such as the selection of electrode materials, the shape and layout of the anode and cathode, the voltage and current of electrochemical equipment, the flow rate, temperature, and mineral content. Existing research has primarily focused on the influence of electrode materials and current density on descaling efficiency, while neglecting external factors such as water flow rate and temperature. In order to further explore the internal and external factors affecting the descaling performance of descaling machines, this study constructed an experimental platform for a descaling machine fouling device. Different voltages, currents, water flow rates, and temperatures were studied to assess the descaling efficiency of the descaling machine. The results indicated that under the conditions of a temperature of 30 °C, a flow rate of 0.35 m/s, a voltage of 24 V, and a current of 10 A, the fouling resistance effect of the electrochemical descaling device was optimal. This provides a new perspective for further improving the descaling efficiency of descaling machines and conducting parameter optimization. Full article

The World Health Organization (WHO) recommends the introduction of a water safety plan (WSP) approach on drinking water, in all types of settings. This study represents the first WSP developed on the Neptune Fountain, in Bologna (Italy), based on an interdisciplinary approach, integrating hydraulic and microbiological features, in a Building Information Modeling (BIM). The aim was to develop a dynamic and digital platform to update and share the maintenance program, promoting collaboration among microbiologists, engineers, and municipal staff. Water samples were collected along fountain water distribution systems (WDS) from 2016 to 2021 to monitor water quality through the heterotrophic bacteria at 22 °C and 37 °C, as well as to conduct an Enterococci, Coliform bacteria, Escherichia coli, Pseudomonas aeruginosa, Clostridium perfringens, and Staphylococcus aureus assessment. Simultaneously, hydraulic measures were performed, and advanced geomatics techniques were used to detect the WDS structural components, with a focus on the water treatment system (WTS). The WTS consisted of 10 modules corresponding to specific treatments: descaling, carbon–sand filtration, reverse osmosis, and ultraviolet disinfection. Fecal indicators, heterotrophic bacteria, and P. aeruginosa exceeded the reference limits in most of the modules. Several disinfections and washing treatments, other than changing the maintenance procedure scheduling, were performed, improving the WTS and controlling the contamination. The developed microbiological results, hydraulic measurements, and maintenance procedures were integrated in the BIM model to optimize the data storage, updating procedures and the real-time data sharing. This approach improved the fountain management, operation, and material conservation, ultimately preserving the health of daily visitors. Full article

Descaling roll is a key component used to remove iron oxide on billet surface in hot rolling production lines, and its surface properties have a significant effect on the quality of hot rolling products. The descaling roll is in bad service condition and subjected to the dynamic impact caused by high-pressure water erosion and high temperature billet descaling process for a long time. Under the action of high temperature, strong wear, multi-cycle heat, force, flow and multi-field strong coupling, the surface is prone to wear and corrosion failure, which affects the continuous rolling production. Submerged arc welding provides an effective way to repair and strengthen the descaling roll surface. The content of WC hard phase has a significant effect on welding quality. At the same time, direct submerged arc welding of Ni based WC wire on the descaling roll surface is easy to cause cracks, and a gradient synergistic strengthening effect can be formed by setting the transition bottom layer in welding. At present, there is a lack of experiments related to the preparation of flux-cored wire with different contents and the overlaying for the bottom submerged arc welding. Relevant studies are urgently needed to further reveal the welding process mechanism to provide significant theoretical support for the preparation of wire materials and the improvement of welding quality. In this paper, 30% and 60% WC flux-cored wires were prepared by employing Ni-Cr-B-Si alloy powder as the base powder, and submerged arc welding tests were conducted on the descaling roll, preparing three welding layers, namely 70% NiCrBSi + 30% WC without the bottom layer, 70% NiCrBSi + 30% WC with the bottom layer, and 40% NiCrBSi + 60% WC with the bottom layer. The properties of the welding layer were evaluated by SEM, XRD, EDS, hardness, friction and wear, corrosion and impact experiments. The results show that the WC hard phase added in the filler metal has dissolved and formed a new phase with other elements in the melting pool. The surfacing layer mainly contains Fe-Ni, Cr-C, Fe₃Si, Ni₃C and other phases. The surfacing layer prepared by a different amount of WC flux-cored wire and the surfacing layer with or without the bottom layer have great differences in microstructure and properties. This study lays a significant theoretical foundation for optimizing the submerged arc welding process and preparing welding materials for the descaling roll and has significant practical significance and application value. Full article

In this study, a circulating water experimental system was constructed to investigate the scale inhibition, scale removal, corrosion inhibition, and disinfection effects of industrial circulating water under the combined action of electromagnetic and electrochemical fields. The influence of these effects on water quality parameters and their scale inhibition and corrosion inhibition effects on hanging plate experiments were examined. Qualitative and quantitative analyses of scale samples were conducted using XRD (X-ray diffraction) and SEM (scanning electron microscopy), along with the evaluation of changes in water quality parameters (such as conductivity, hardness, Chemical Oxygen Demand (COD), turbidity, iron ions, and chloride ions) before and after the experiments. The results showed that after 360 h of circulation experiment, at a water temperature of 30 °C, electromagnetic field frequency of 1 kHz, electrochemical scale removal device voltage of 24 V, current of 10 A, and water flow rate of 0.6 m/s, the transformation of calcite to aragonite in CaCO₃ scale samples occurred, with a 76.6% increase in aragonite content. Moreover, the conductivity decreased by 11.6%, hardness decreased by 42.0%, COD decreased by 59.7%, turbidity decreased by 48.1%, and chloride and iron ion concentrations decreased by 36.6% and 63.1%, respectively. The scale inhibition efficiency reached 53.8%, surpassing the effects of electromagnetic and electrochemical actions individually. These findings demonstrate that the combined action of electromagnetic and electrochemical fields can effectively enhance scale inhibition, scale removal, corrosion inhibition, and disinfection and algae removal effects. Full article

The descaling roller is a significant component in steel rolling production. Under harsh service conditions, the descaling roller is subjected to the dynamic impact caused by high-pressure water erosion and a high-temperature billet descaling process for a long time. Under the harsh conditions of high temperature, strong wear, multi-cycle heat, force, flow, and multi-field strong coupling, the roller surface is prone to wear and corrosion failure, which affects the production cost and efficiency. Through plasma surfacing technology, a high-performance coating can be applied on the conventional metal surface to effectively improve its surface properties. It is important to carry out experimental research on the surface plasma surfacing of the descaling roller to prolong product life, improve product quality, and save cost. At present, the research on the 42CrMo scaler matrix plasma surfacing of nickel-based alloys with different WC contents is still lacking. In this paper, 70%NiCrBSi+30%WC powder and 40%NiCrBSi+60%WC powder were used as surfacing materials; plasma surfacing experiments were carried out on the 42CrMo matrix; and SEM, XRD, microhardness, friction and wear, and corrosion tests were carried out on the surfacing layer to evaluate the feasibility of preparing an ultra-high-hardness WC-particle-reinforced nickel-based alloy plasma surfacing layer on the descaling roller surface and to explore the WC hard phase dissolution behavior and complex secondary phase formation mechanism. The results show that γ(Fe/Ni), Fe-Ni, FeSi, Fe₃C, and M₇C₃ are the main phases in the Ni/WC plasma surfacing layer. The diffusion and precipitation of elements occur in the molten pool, and complex secondary phases are formed in the surfacing layer. Compared with the 70%NiCrBSi+30%WC surfacing layer, the WC deposition phenomenon of the 40%NiCrBSi+60%WC surfacing layer has been significantly improved and has better hardness, wear resistance, and corrosion resistance. Based on the welding test, the correlation law between powder formulation, welding structure, and surfacing layer properties was revealed in this study, which lays a theoretical foundation for the preparation of high-performance coating on the descaling roller surface and has significant engineering application value and practical significance. Full article