Pulsed Process Research Articles

Mathematical Processing of Pulses for Improving the Timing Characteristics of the Correlation Counter

Mathematical Processing of Pulses for Improving the Timing Characteristics of the Correlation Counter

Investigation of the Effect of Nanosecond Laser Pulses Processing on the Microstructure and Fatigue Resistance of Commercially Pure Titanium

Investigation of the Effect of Nanosecond Laser Pulses Processing on the Microstructure and Fatigue Resistance of Commercially Pure Titanium

Shaping the Structure and Properties of TiO2-ZnO Oxide Coatings Produced by Plasma Electrolytic Oxidation on Titanium Substrate.

The paper presents the results of preliminary research on the possibility of synthesizing ZnO-TiO2 mixed coatings by plasma electrochemical oxidation (PEO). The aim of the work was to synthesize TiO2-ZnO mixed coatings on a titanium substrate from an electrolyte containing ZnO nanoparticles (NPs) and to assess the parameters of PEO on the structure, chemical composition, and properties of the obtained oxide coatings. The PEO process was carried out under various current-voltage conditions using different signals: DC, DC pulse, and AC. In this work, optimal conditions for the PEO process were determined to obtain well-adhering oxide coatings with the highest possible content of ZnO. The structure and morphology of the resulting oxide coatings were investigated, and their chemical and phase composition was comprehensively examined (EDX, XRD, XPS, and GD-OES). In addition, their basic optical properties were assessed. It has been shown that in the PEO DC pulse process, it is possible to obtain oxide coatings characterized by a high degree of structure order, high ZnO content in the oxide coating (3.6 at.%, XPS), and prospective applications for photocatalytic purposes (3.12 eV).

Van der Waals Epitaxy, Superlubricity, and Polarization of the 2D Ferroelectric SnS.

Tin monosulfide (SnS) is a two-dimensional layered semiconductor that exhibits in-plane ferroelectric order at very small thicknesses and is of interest in highly scaled devices. Here we report the epitaxial growth of SnS on hexagonal boron nitride (hBN) using a pulsed metal-organic chemical vapor deposition process. Lattice matching is observed between the SnS(100) and hBN{11̅0} planes, with no evidence of strain. Atomic force microscopy reveals superlubricity along the commensurate direction of the SnS/hBN interface, and first-principles calculations suggest that friction is controlled by the edges of the SnS islands, rather than interface interactions. Differential phase contrast imaging detects remnant polarization in SnS islands with domains that are not dictated by step-edges in the SnS. The growth of ferroelectric SnS on high quality hBN substrates is a promising step toward electrically switchable ferroelectric semiconducting devices.

Modelling cowpea beans [formula omitted]-galactosidase inactivation dependence on temperature and moisture content

Hydrothermal treatment improves the digestibility of pulses through the coupled phenomena of enzymatic degradation and diffusion of galacto-oligosaccharides, despite the thermal inactivation of α-galactosidase at mild temperatures. To better understand the key process parameters that influence the balance between enzyme activity and its inactivation, the kinetics of α-galactosidase inactivation were investigated in a cowpea-water system at a broad range of temperatures (45 °C ≤T≤ 60 °C), moisture contents (0.16 g/g dry basis, d.b. ≤W≤ 0.85 g/g d.b.) and treatment times (5 min ≤t≤ 7.5 h). For moisture contents ranging from 0.25 to 0.85 g/g d.b., the higher the temperature the faster the inactivation of α-galactosidase; while for 0.16 g/g d.b., the relative enzymatic inactivation was not temperature-dependent. A first-order model was successfully fitted to the experimental data, whereas the temperature dependence of inactivation rate followed the Arrhenius model. The influence of moisture content on the enzymatic inactivation rate was remarkable. The inactivation rate constant at excess water (0.85 g/g d.b.) was five times higher than the samples at limited water (0.35 g/g d.b.) condition. The results showed moisture-dependent α-galactosidase inactivation kinetics mainly at mild temperatures (55 and 60 °C), with implications for the representation of diffusion-reaction phenomena during hydrothermal processing of pulses.

Low-k SiOx/AlOx Nanolaminate Dielectric on Dielectric Achieved by Hybrid Pulsed Chemical Vapor Deposition.

Selective and smooth low-k SiOx/AlOx nanolaminate dielectric on dielectric (DOD) was achieved by a hybrid water-free pulsed CVD process consisting of 50 pulses of ATSB (tris(2-butoxy)aluminum) at 330 °C and a 60 s TBS (tris(tert-butoxy)silanol) exposure at 200 °C. Aniline selective passivation was demonstrated on W surfaces in preference to Si3N4 and SiO2 at 300 °C. At 200 °C, TBS pulsed CVD exhibited no growth on W or SiO2, but its growth was catalyzed by AlOx. Using a two-temperature pulsed CVD process, ∼2.7 nm selective SiOx/AlOx nanolaminate was deposited on Si3N4 in preference to aniline passivated W. Nanoselectivity was confirmed and demonstrated on nanoscale W/SiO2 patterned samples by TEM analysis. For a 1:1 Si:Al ratio, a dielectric constant (k) value of 3.3 was measured. For a 2:1 Si:Al ratio, a dielectric constant (k) value of 2.5 was measured. The k value well below that of Al2O3 and SiO2 is consistent with the formation of a low-density, low-k SiO2/Al2O3 nanolaminate in a purely thermal process. This is the first report of a further thermal CVD process for deposition of a low-k dielectric and the first report for a selective low-k process on the nanoscale.

Multi-layer additive manufacturing on nickel-based superalloy by optimization of pulsed mode process parameters of single-layer bead geometry

Recent advancements in the wire arc additive manufacturing (WAAM) process for nickel-based superalloys have had a substantial impact on metal additive manufacturing industries such as aerospace, energy, and construction. The input process parameters influence the WAAM part's dimensional accuracy, process stability, and other critical impacts. The quality of each weld layers in WAAM can be controlled by various process parameters. In this study, a single-layer bead was deposited from Hastelloy C-22 using the pulsed mode gas tungsten arc welding (PC-GTAW) process. The chosen input process parameters include pulse frequency (X1), peak current (X2), and pulse on time (X3). The design of experiments (DoE) statistical quality tool was used to optimize the parameters, and the response surface m`ethodology (RSM) technique was used to develop the design matrix. The experiments were conducted based on central composite design (CCD), and their resulting responses bead width (Y1), height (Y2), and depth of penetration (Y3) were evaluated using optical microscopy. The results of the geometrical analysis have revealed a significant correlation between the characteristics of the layer and the parameters of the process. The analysis of variance (ANOVA) method was employed to verify the validity of the actual and predicted models. The model was experimentally validated using the established optimal process parameters, and the mechanical and metallurgical performance was evaluated. The microstructure of the single-layer exhibits equiaxed, cellular, and columnar structures at various regions. The pulse mode process was found to effectively reduce elemental segregation, improve the microstructure, and enhance the mechanical properties of the weld layer. The multi-layer experiments were carried out using the optimal process parameters of a single layer. According to metallographic investigations, the multi-layer that has been deposited exhibits a lack of cracks and porosity. This study provides new insights into the stabilized properties necessary to achieve optimal process parameters and metallurgical characteristics in the robust wire arc additive manufacturing of Hastelloy C-22.

Small RCS targets detection based on pulse compression radar signal generator and processor

In the last two decades, field programmable gate arrays (FPGAs) have become the leading technology for implementing real time systems, specially radars. The most important advantage of FPGA is its parallel nature of executing complicated algorithms. As a result, the received data flow will be processed in a real time manner, which is suitable for radar applications. This paper attempts to show the design and the FPGA implementation of a binary phase-coded pulse compression radar signal generator and processor, that are intended to determine the ranges, and the speeds of targets with small radar cross-section area like drones. The system operating waveform is a bi-phase sequence, that is known to have the best known peak sidelobe level compared to compound Barker codes of the same length. In addition, the design incorporates a range sidelobes cancellation method to remove the time sidelobes in the matched filter output. Also, we are going to represent and investigate the FPGA implementing steps of the radar waveform generator and processor according to the required parameters. Finally, the implementation results of the proposed system will be represented.

Effect of femtosecond laser bionic texture on anti-wear properties of medical Ti-6Al-4 V

Ti-6Al-4 V (TC4) is used as a medical implant material. However, its wear resistance is poor, which is not conducive to the use of implants. In this study, three biomimetic textures were designed on the surface of materials by femtosecond pulsed laser processing technology. The wear resistance of the textured surface was studied by rotating dry friction. The results demonstrate that the textured surface effectively reduces and captures the generation of wear particles, leading to enhanced stability of TC4 during wear and reduced surface wear. Compared with the untextured surface, the wear of the textured surface is reduced by 73.68%. These results indicate that bionic texture can improve the wear resistance of TC4.

Conventional and emerging innovative processing technologies for quality processing of potato and potato-based products: A review

Potatoes are a widely consumed staple food and a key ingredient in numerous food products such as French fries, chips, mashed potatoes and various snacks. The quality of potato products is heavily influenced by the processing methods employed during production. Conventional technologies such as thermal blanching, frying and drying have been widely used for processing potatoes over the years. However, these technologies may lead to the loss of essential nutrients and changes in sensory properties such as texture, color and flavor. In recent years, innovative emerging technologies have been developed to improve potato processing efficiency and product quality while preserving the nutritional and sensory properties of potato products. These technologies include ultrasound processing, pulsed electric field processing, microwave and radiofrequency processing. This review examines the impact of these technologies on the quality attributes of potato products and highlights the importance of selecting appropriate processing technologies for different potato products to achieve the desired quality attributes. In conclusion, this review provides valuable insights into the current trends and advances in the potato processing technologies and emphasizes the need for the continued research and development to optimize these technologies for the production of high-quality potato products. The adoption of emerging technologies has the potential to drive innovation and improve the overall sustainability and efficiency of potato processing, ensuring that potato-based products continue to meet the evolving demands of consumers.

Modifying the Local Structure and Properties of Zinc-Substituted Hexagonal Barium Ferrites for Microwave Devices via Magnetic Pulse Processing

Modifying the Local Structure and Properties of Zinc-Substituted Hexagonal Barium Ferrites for Microwave Devices via Magnetic Pulse Processing

Modification of the local structure and properties of zinc-substituted hexagonal barium ferrites for microwave devices under magnetic pulsed processing

The results of studies of the effect of magnetic pulse treatment on the local structure and magnetic properties of substituted ferrite for microwave devices are presented. The change in the magnetic properties of ferrites as a result of exposure to them by pulses of a weak magnetic field indicates the possibility of controlling the parameters of ferrites by means of a magnetic field and thereby influence the resonant characteristics of microwave devices based on them.

Microanalysis of Active Nitrogen Oxides (RONS) Generation Characteristics during DC Negative Corona Discharge at a Needle-Plate Electrode

The DC negative corona of needle-plate electrodes can generate atmospheric pressure low-temperature plasma active particles, which have important effects on biological mutagenesis. The DC negative corona discharge of an air needle-plate electrode with effective consideration of NOx particles was simulated and the Trichel pulse current was obtained, focusing on the development of particles and the distribution of active nitrogen oxides (RONS) at four moments in the pulse process. The simulation results indicate that the positive ions (N2+ and O2+) and negative ions (O− and O2−) were closely related to the current changes, and the negative ions (O− and O2−) presented a typical stratification phenomenon. RONS (H2O2, O3, and NO) were approximately uniformly distributed above the level of the plate electrode at the same instant, with H2O2 and O3 except for the area below the needle tip. They trended to a cumulative increase in concentration with time. This study provides a theoretical basis for corona discharge plasma seed treatment technology.

The role of asymmetric metal flow on weld formation and solidification characteristics during pulsed laser butt welding with assembly tolerance

In comparison to other laser-assisted welding techniques, the pulsed laser welding process (PLBW) provides cost-effectiveness and ease of operation while effectively connecting butt-assembled thin plates with manufacturing tolerances (both air gap and edge misalignment). A combination of numerical simulations and experimental studies was conducted to analyze the forming mechanism and solidification behavior of the weld. In this paper, a transient three-dimensional heat-flow-metallurgical model has been established for a PLBW process of mild steel plates with a thickness of 1.8 mm. The predicted weld pool profiles were consistent with the experimental findings. The finding suggested the molten metal, driven by surface tension and recoil pressure, successively generated liquid bridges on the rear and front sides of the pool. The two sheets were joined as the molten metal gradually solidified. The energy absorptivity was highly correlated with the weld pool and keyhole dynamics, and the laser energy absorbed by the metal was mainly transferred in the form of thermal convection. The kinematic features of the melt were observed by the liquid phase mass transfer rate and surface fluctuations. According to the Fourier analysis results, the molten pool oscillated at the characteristic frequency of the laser pulse frequency. The spatial and temporal distributions of solidification parameters aided in analyzing the solidification features within the pool. The asymmetric flow had a greater influence on the temperature gradient. These findings addressed the roles of PLBW on fluid flow, heat behaviors, and solidification parameters of welds with assembly tolerances, as well as the reasons for improved weld formation.

Improvement of the technological process of obtaining initial pear plants

The process of obtaining initial pear plants is considered. The technological process includes the selection of plants of a certain variety according to pomological, physiological qualities and productivity; diagnostics for the presence of viruses, phytoplasmas and other harmful organisms by ELISA, PCR and indicators testing; in the absence of healthy plants – release from pathogens by methods of thermotherapy, chemotherapy, in vitro culture, magnetotherapy with re-testing. After preliminary testing in greenhouse conditions, candidate plants for initial plants are obtained, which are then subjected to testing using a set of diagnostic methods. Plants free from the main harmful viruses and phytoplasma are transferred to the category of “initial plants”, and if all the tested plants are infected, they are subjected to recovery. Dry air thermotherapy in combination with grafting of apexes on virus-free rootstocks provides the possibility of obtaining healthy plants during one growing season. For chemotherapy, along with reference drugs (ribavirin), the use of phenolic compounds (salicylic, gallic acids) is promising, which can increase the efficiency of plant recovery from viruses by an average of 28–30%, reduce the cost of the recovery process and improve workplace safety. The use of magnetic pulse processing increases the environmental safety of the technology in the absence of the phytotoxic effect. After diagnosis by a complex of methods in the absence of viruses, pear plants receive the category “initial plant” and are further propagated by budding or grafting.

Exploring morphological diversity of Q-carbon structures through laser energy density variation

This article presents a study on preparing and characterising Q-carbon structures through ultrafast cooling of annealed amorphous carbon using a nanosecond KrF excimer laser. The experiments were conducted under high vacuum conditions. Different Q-carbon structures resembling fibers, clusters, microdots, and combinations of clusters with nanodots were successfully prepared by varying the beam energy density (ranging from 0.6 to 1.8 J cm−2) during the pulsed laser annealing process. The resulting changes in surface morphology were analysed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Additionally, the modified forms of carbon were investigated through energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The findings reveal that increasing the beam energy density during the pulsed laser annealing process led to a corresponding increase in the percentage of sp3 hybridisation in the samples. The highest sp3 content, reaching 83 %, was observed in the sample with the highest energy value of 1.8 J cm−2, where the fastest undercooling occurred. In addition, we evaluated the antibacterial potential of the prepared sample (1.0 J) using two bacterial strains, one gram-positive of S. aureus and one gram-negative of E. coli.

Design on Formation of Nickel Silicide by a Low‐Temperature Pulsed Laser Annealing Method to Reduce Contact Resistance for CMOS Inverter and 6T‐SRAM on a Wafer‐Scale Flexible Substrate

AbstractA pulsed laser annealing method is utilized to directly synthesize nickel silicide (NiSi) as a contact material to improve the contact of electric devices. Three laser wavelengths, 355 nm (ultraviolet laser), 532 nm (green laser), and 1064 nm (infrared laser), are used for the NiSi synthesis during the pulsed laser annealing process. A NiSi phase with low sheet resistance is formed by an ultraviolet laser annealing (ULA) process without damaging the polyimide (PI) substrate. With the integration of the ULA process‐induced NiSi into p‐nnel MOSFET (PMOS) and n‐channel MOSFET (NMOS) devices, the on/off ratio improves significantly, and the field‐effect mobility increases by 30% because of the reduction in contact resistance from 21 to 8.5 kΩ. In addition to the PMOS and NMOS, the gains of the CMOS inverter at different Vdd values are improved by at least 30%. Moreover, the static noise margin of 6T‐SRAM is elevated from 0.82 to 1 V at Vdd = 4 V. The ability of the ULA process to synthesize a high‐quality NiSi layer on a flexible substrate is demonstrated. The integration of NiSi into electrical devices offers a new pathway for improving the electrical behavior of flexible devices.

Mathematical modelling and validation of twist-free lead crowning of spur gears by pulsed electrochemical flank modification process

Mathematical modelling and validation of twist-free lead crowning of spur gears by pulsed electrochemical flank modification process

Ultra-short pulsed laser processing of single crystalline diamonds for tooling applications

This study investigates the feasibility of using ultra-short pulsed (USP) lasers to fabricate single crystalline diamond (SCD) tools. SCD has exceptional mechanical, tribological, and thermal properties and offers excellent performance in the precision machining of hard and brittle materials over polycrystalline diamond and diamond-coated tools. However, the anisotropic nature of the SCD makes it difficult for laser machining because the material shows susceptibility to cracking, defect growth, and breakout depending on its crystallographic orientation. Anisotropy needs to be considered while optimizing the geometry of the tool to minimize wear and improve tool performance. An advanced four-axis laser machining approach with optimized laser parameters and temporal beam shaping is used to mitigate challenges related to defect growth and orientation dependence, leading to the production of high-quality single cutting-edge SCD tools. Cylindrical diamonds and diamond crystals with top surface planes {100} and {111} are used in the study. The occurrence of defects in the diamond when laser machined and their dependence on the crystallographic orientation along the circumference of the diamond is thoroughly investigated via SEM, electron backscatter diffraction, and light microscopy images. Finally, the laser-manufactured SCD tools are tested by turning fully sintered zirconia ceramics (3Y-TZP-A). USP laser machining of SCD is demonstrated to be a viable alternative to traditional manufacturing methods for producing high-quality SCD tools with unique properties and performance. The results further emphasize the importance of understanding the crystallographic orientation dependence when laser machining crystalline materials like diamonds.

Distinguishing evaluation of plastic deformation and fatigue damage using pulsed eddy current testing

The vessels and pipes of nuclear power structures are subjected to complex forces. The structures suffer sudden loads that lead to plastic deformation and cyclic loads that result in fatigue damage. In practice, two types of microscopic damage may occur simultaneously. The effect of plastic deformation on material fatigue properties remains unclear, and there is a lack of effective methods to distinguish plastic deformation and fatigue damage. To address these issues, the fatigue life curve of 304 stainless steel is experimentally measured, and the influence of fatigue life due to the presence of plastic deformation under a certain load is investigated. It's identified that preset plastic deformation below 15% will increase the fatigue life of the structure. Additionally, a pulsed eddy current signal processing and reconstruction method based on the empirical modal decomposition (EBD) method is proposed. Finally, the pulsed eddy current signal characteristics of plastic deformation and fatigue damage are analyzed, and a distinguishing evaluation method of fatigue damage with preset plastic deformation is established.