Surface Distribution Research Articles

Alumina Crucibles from Free Dispersant Suspensions: A Useful Labware to form Advanced Powders for Radiation Dosimetry

Background: Powder technology provides conditions to control particle-particle interactions that drive the formation of final-component/material, which also includes the crystalline structure, microstructure and features. Alumina (Al2O3) is the most studied ceramic based material due to its useful properties, disposal, competitive price, and wide technological applicability. This work aims to produce alumina crucibles with controlled size and shape from free dispensant suspensions. These crucibles will be used as containers for the synthesis of new materials for radiation dosimetry. Methods: The Al2O3 powders were characterized by XRD, SEM, PCS, and EPR. The stability of alumina particles in aqueous solvent was evaluated by zeta potential determination as a function of pH. Alumina suspensions with 30 vol% were shaped by slip casting in plaster molds, followed by sintering at 1600oC for 2 h in an air atmosphere. Alumina based crucibles were characterized by SEM and XRD. Results: ɑ-Al2O3 powders exhibited a mean particle diameter size (d50) of 983nm. Besides, the stability of particles in aqueous solvent was achieved at a range of pH from 2.0-6.0, and from 8.5-11.0. EPR spectra revealed two resonance peaks P1 and P2, with g-values of 2.0004 and 2.0022, respectively. The as-sintered ɑ-alumina based crucibles presented uniform shape and controlled size with no apparent defects. In addition, the final microstructure driven by solid-state sintering revealed a dense surface and uniform distribution of grains. Conclusion: The ɑ-Al2O3 crucibles obtained by slip casting of free dispensant alumina suspensions, followed by sintering, exhibited mechanical strength, and controlled shape and size. These crucibles will be useful labwares for the synthesis of new materials for radiation dosimetry.

Characterizing the marine iodine cycle and its relationship to ocean deoxygenation in an Earth system model

Abstract. Iodine (I) abundance in marine carbonates (measured as an elemental ratio with calcium, I / Ca) is of broad interest as a proxy for local/regional ocean redox. This connection arises because the speciation of iodine in seawater, the balance between iodate (IO3-) and iodide (I−), is sensitive to the prevalence of oxic vs. anoxic conditions. However, although I / Ca ratios are increasingly commonly being measured in ancient carbonate samples, a fully quantitative interpretation of this proxy requires the availability of a mechanistic interpretative framework for the marine iodine cycle that can account for the extent and intensity of ocean deoxygenation in the past. Here we present and evaluate a representation of marine iodine cycling embedded in an Earth system model (“cGENIE”) against both modern and paleo-observations. In this framework, we account for IO3- uptake and release of I− through the biological pump, the reduction in ambient IO3- to I− in the water column, and the re-oxidation of I− to IO3-. We develop and test a variety of different plausible mechanisms for iodine reduction and oxidation transformation and contrast model projections against an updated compilation of observed dissolved IO3- and I− concentrations in the present-day ocean. By optimizing the parameters controlling previously proposed mechanisms involved in marine iodine cycling, we find that we can obtain broad matches to observed iodine speciation gradients in zonal surface distribution, depth profiles, and oxygen-deficient zones (ODZs). However, we also identify alternative, equally well performing mechanisms which assume a more explicit mechanistic link between iodine transformation and environment – an ambiguity that highlights the need for more process-based studies on modern marine iodine cycling. Finally, to help distinguish between competing representations of the marine iodine cycle and because our ultimate motivation is to further our ability to reconstruct ocean oxygenation in the geological past, we conducted “plausibility tests” of different model schemes against available I / Ca measurements made on Cretaceous carbonates – a time of substantially depleted ocean oxygen availability compared to modern and hence a strong test of our model. Overall, the simultaneous broad match we can achieve between modeled iodine speciation and modern observations, and between forward proxy modeled I / Ca and geological elemental ratios, supports the application of our Earth system modeling in simulating the marine iodine cycle to help interpret and constrain the redox evolution of past oceans.

Angle-based residual strength estimation between geotextile/textured geomembrane interface

Geotextile and geomembrane are widely used in landfill liner systems, but the relationship between geomembrane roughness and geotextile/geomembrane interface residual shear strength remains to be studied. In this paper, by using a large-scale ring shear apparatus, a series of ring shear tests between geotextile/geomembrane was conducted, and the profile inclined angle distribution of the textured geomembrane surface was obtained by a profilometer. The experiment results showed that the geotextile/geomembrane interface has reached the residual status after a shear displacement of 3 m, and the average inclined angle of textured geomembrane was close to zero. With the increase of geomembrane asperity height, the interface residual strength increases. Through force analysis and statistical analysis, quantitative relationships between residual shear strength between geotextile/co-extruded geomembrane and geotextile/cone-shape structured geomembrane interfaces and inclined angle distribution were established. The model was validated by test results and case analysis. This study helps understand the mechanism that how the textured geomembrane surface caused high interface residual strength, and choose geomembrane with appropriate roughness to provide adequate residual strength in engineering applications.

Nano-Pd/SiO2 aerogel catalyst prepared via ambient pressure drying process using perlite powder in hydrogenation and cross-coupling reactions

Perlite, a cheap silica source with abundant reserves in countries such as Türkiye, China, and Greece, was used to produce nano Pd-doped silica aerogel powder for the first time in this study. The microstructure and morphology of the prepared silica aerogel powder were examined using SEM, FE-SEM, and TEM. The phases of the silica aerogel powders were analyzed via XRD (X-ray Diffraction) technique. The chemical bonding of the surface modifier with aerogels was analyzed by Fourier transform infrared spectroscopy (FTIR, Spectrum RX-1, Perkin Elmer). Surface areas, pore volumes, distributions, and particle sizes of the alumina-silica-based aerogel powders with a porous structure were measured using a Micromeritics/ASAP 2020 brand BET (Brunauer, Emmet, and Teller) device in a liquid nitrogen gas environment at 77K.The efficiency of this nano Pd-doped silica aerogel powder was investigated as a heterogeneous catalyst for well-known transformations in organic synthesis, such as alkene hydrogenation and cross-linking reactions. The results indicated that the developed method is chemoselective, reducing only carbon-carbon multiple bonds without affecting C-N or C-O multiple bonds, such as carbonyl and nitrile. The effectiveness of the newly developed catalyst was also investigated in Heck and Suzuki-Miyaura reactions, yielding the targeted products with high efficiency.Thus, an inexpensive, economical, and environmentally friendly method has been developed that is potentially applicable in the hydrogenation and cross-coupling reactions of alkenes.

Luminescence Patterns on Multimillimeter Single-Crystal MAPbBr3 Microplatelets via Thermal Ablation Effects.

The single crystal distinguishes itself as the most outstanding representative of excellent optoelectronic performance among perovskite semiconductors due to its exceptional charge carrier properties, extraordinary optophysics, precise structural geometries, and superior material stabilities. However, it exhibits mediocre performance in light emission, which can be attributed to its excessive carrier diffusion lengths and extremely low recombination rates. To address this challenge, this study puts forward a controllable high-temperature annealing treatment strategy concentrating on multimillimeter-scale MAPbBr3 micrometer-thick platelet single crystals (MPSCs). Through the utilization of thermal ablation effects to convert the surface monocrystalline lattices into polycrystalline perovskite nanocrystals (PNCs) with a remarkably increased specific surface area, the fluorescence intensity arising from the rapid recombination of free carriers on the PNC surface is enhanced by 320 times compared to the pristine MPSC surface. These PNCs produced through surface annealing, with the characteristic of loose adhesion to surfaces, can be mechanically wiped away and regenerated in situ via reannealing the residual MAPbBr3 MPSCs, guaranteeing high intensity, durability, and standard geometric fluorescence. Moreover, by regulating the surface distributions of thermal ablation effects and carrying out embossing annealing treatment or laser direct writing, we can design and fabricate relatively complex, high-contrast (255×), and clearly resolved fluorescence patterns on MPSC surfaces.

Adaptive Beamforming for On-Orbit Satellite-Based ADS-B Based on FCNN.

Digital multi-beam synthesis technology is generally used in the on-orbit satellite-based Automatic Dependent Surveillance-Broadcast (ADS-B) system. However, the probability of successfully detecting aircraft with uneven surface distribution is low. An adaptive digital beamforming method is proposed to improve the efficiency of aircraft detection probability. The current method has the problem of long operation time and is not suitable for on-orbit operation. Therefore, this paper proposes an adaptive beamforming method for the ADS-B system based on a fully connected neural network (FCNN). The simulation results show that the calculation time of this method is about 2.6 s when more than 15,000 sets of data are inputted, which is 15-80% better than the existing methods. Its detection success probability is 10% higher than those of existing methods, and it has better robustness against large amounts of data.

Voltage-induced rearrangement in silver nanoparticles spatial distribution produced by EAFD method and its LSPR optimization

Abstract This paper presents a voltage-induced and thermal annealing rearrangement (VITAR) method based on modified electric field assisted film dissolution method as a flexible and powerful tool for manipulating nanoparticles spatial distribution based on drift and diffusion mechanisms that occur due to external DC voltage and thermal annealing processes. Different samples with various arrangements of external DC voltage and thermal annealing processes have been produced. The extinction and attenuated total reflection (ATR) spectra, as well as atomic force microscope (AFM) images, have been employed to investigate their optical and morphological properties. Four cases with arrangements of DV-Anl, DV-Anl-DV, DV-Anl-IV, and DV-IV-Anl have been studied. The AFM images show that by applying secondary voltage (direct or inverse voltage), it is possible to drift nanoparticles and change its morphology (size and shape) as well as surface and volume distributions. As a result, by applying a secondary direct voltage (in the DV-Anl-DV case), the surface density of nanoparticles decreases due to direct drift force. It is notable that in this case, the extinction peak and ATR depth have not significantly changed. By applying a secondary inverse voltage (in the DV-Anl-IV, and DV-IV-Anl cases), an increase in the surface density of the nanoparticles has been observed. Also, the extinction peak has increased, and the ATR depth has decreased in the DV-Anl-IV case, but in the DV-IV-Anl case, due to the uniform size of surface nanoparticles, the resonance power has shown a significant increase in both extinction and ATR spectra compared to other cases. The resulting changes in extinction and ATR spectra show that by using the VITAR process, the surface structure, morphology and its optical properties can be optimized and this method provides a great opportunity to enhance Localized Surface Plasmon Resonance effects, which can be employed in nano-optical devices.

Optimization of the performance of copper/graphite system for GIL Tri‐post grounding electrode based on plasma sintering technology

Grounding electrodes, as crucial components of GIL bushings, experience friction with the GIL shell during long-term operation, generating metal particles that induce partial discharge. This phenomenon can lead to internal insulation breakdown, severely compromising GIL operation. This study focuses on enhancing the wear resistance of grounding electrodes by proposing a solution involving copper-graphite composites. Copper/graphite composite materials were fabricated using Spark Plasma Sintering technology. Additionally, the impact of graphite content and particle size on wear resistance, hardness, and electrical conductivity was comprehensively analyzed. Performance evaluation using radar chart analysis identified the optimal solution. The results indicate that at a sintering temperature of 960 °C, pressure of 45 MPa, and holding time of 15 min, with a graphite mass fraction of 7 %, the grounding electrode material exhibits a smooth surface and uniform distribution of graphite. Furthermore, when the graphite particle size is 4 μm, the friction coefficient remains approximately 0.7 with minimal fluctuations. The abrasion produces scratches measuring only 190 μm, and the wear rate is recorded at 2.1128 × 10−4 mm³/N·m, while the hardness reaches 59.6 HV, an increase of 19.6 HV compared to a particle size of 40 μm. In conclusion, an appropriate graphite content effectively enhances the wear resistance of the grounding electrode, and a reduction in graphite particle size optimizes overall performance. When the composite material contains 7 % graphite with a particle size of 4 μm, the performance is optimal, allowing the grounding electrode to maintain its original properties while demonstrating excellent wear resistance. This study provides a significant approach to optimizing the performance of grounding electrodes.

Effect of Pulse Electrodeposition Mode on Microstructures and Properties of Ni-TiN Composite Coatings

Mild steel is a kind of material commonly used in the chemical industry and to manufacture machinery, farm tools, and other parts in order to improve the surface performance of the parts and prolong their service life. The Ni-TiN composite coating was fabricated through ultrasonic electroplating using a Ni-based sulfamic acid bath with added nano-TiN particles. The effects of three distinct current modes, direct current (DC), positive pulse current (PC), and positive–negative pulse current (PNPC), on various aspects of the coating, including surface morphology, TiN content and distribution, interface bonding strength, microhardness, friction and wear properties, as well as corrosion resistance, were investigated. The findings demonstrated that, in comparison to DC electroplating, PC electrodeposited Ni-TiN composite coatings yielded finer grains, smoother surfaces, reduced surface cracks, increased interface bonding strength, and enhanced corrosion resistance. Furthermore, PNPC electrodeposited Ni-TiN composite coatings showed higher interface bonding strength than those of PC electrodeposited Ni-TiN coatings and had the densest structure, leading to the best corrosion resistance. Pulse current electroplating enhanced the incorporation of nano-TiN particles, with a higher deposition rate observed in positive–negative pulse current electroplating compared to positive pulse current electroplating. Furthermore, the PNPC electrodeposited coating displayed improved microhardness and demonstrated the best friction and wear properties, while the DC electroplated coating displayed the least favorable performance in these aspects.

Investigating Pt/Pumice catalyst for efficient 3-methyl-1-butanol conversion

The objective of this study was to obtain a modified Pt/pumice catalyst to support the conversion reaction of 3-methyl-1-butanol under specific reaction conditions. To achieve this objective, the first step involved preparing modified pumice catalyst pellets by impregnating them with Pt metal followed by activation at a temperature of 500 °C. The second step involved characterizing the Pt/pumice catalyst, including the surface distribution of Pt metal using SEM. The third step involved conducting the catalyst activity test against 3-methyl-1-butanol in a reactor (furnace) at temperatures ranging from 400 to 500°C with a flow system for the feed. The fourth step involved analyzing the conversion results using GC-MS chromatograms. The research results showed that the Si/Al ratio in the modified Pt/Pumice catalyst using a PtCl4 solution with a concentration of 0.0321 M for impregnation was 4:1, compared to 4.8:1 for Pt/Zeolite and 3.2:1 for Pt/ABP. The modified catalyst activity test for 3-methyl-1-butanol showed the following conversion results: Pt/Pumice 27.63%, Pt/Zeolite 23.85%, Pt/Black Pumice 14.81%, and for platinum catalyst, the conversion was 22.35%. These results indicated that the highest conversion was observed in the treated sample A-3 under the reaction condition of 450°C. The conversion products analyzed using GC-MS showed the presence of three molecules: 3-methylbutanal, 2-methylbutanal, and anhydrous isobutanoate.

Extraction of Soluble Dietary Fiber from Sunflower Receptacles (Helianthus annuus L.) and Its Alleviating Effect on Constipation in Mice.

Sunflower receptacles are the main by-product of the processing of Helianthus annuus L. In this study, several extraction methods of soluble dietary fiber (SDF) from sunflower receptacles were evaluated, and then, the physicochemical structure and functional properties of these SDFs were examined. Finally, a mouse constipation model was established to explore its therapeutic potential for constipation. The results showed that the SDF yield of citric acid extraction and enzyme extraction was better than that of hot-water extraction. Structural characterization showed that the three SDF functional groups were similar and amorphous, while the surface distribution of the SDF obtained by the citric acid extraction method (ASDF) had more fine pores. Physicochemical analysis showed that ASDF had the best water-holding capacity, oil-holding capacity, and expansion force. Animal experiments showed that the first black stool defecation time of the model group changed significantly (p < 0.001), indicating that the model was successful. Compared with the model group, the middle- and high-dose groups reduced the first black stool defecation time (p < 0.05 or p < 0.01) and increased the fecal water content (p < 0.05). The high-dose group significantly promoted the intestinal peristalsis of mice (p < 0.05). From hematoxylin-eosin (H&E) staining, it can be seen that the three dose groups of ASDF can improve the damage of mouse colon tissue induced by loperamide hydrochloride to a certain extent. Our results show that ASDF has good physical and chemical properties and laxative properties and has broad development space in the field of health food.

REAL TIME LUMINESCENT DOSIMETRY SYSTEM FOR PRODUCT PROCESSING AT AN ELECTRON ACCELERATOR

Quality control in industrial product processing at an electron accelerator requires continuous monitoring of critical parameters of the irradiation regime, first of all, of absorbed dose. The method of contact-free on-line measuring the surface distribution of absorbed dose in a processed object is described. The novel technique is based on the use of optical radiation induced in the object with the electron beam (cathodoluminescence, CL). It is shown, that the intensity of CL is proportional to the absorbed dose rate. An automated system for online measurement of the CL signal and determination of the scanning beam parameters (profile, width, offset) has been developed. The results of calibration of the absorbed dose by the CL signal in the industrial dose range are obtained. In contrast to the well-known methods of luminescent dosimetry based on thermo- or optically stimulated luminescence, the new approach does not require a special material for detector, as well as its extra stimulation to read out the dosimetry information.

Structural Features of Porous Silicon Formed on Heavily Doped Plates of Single-Crystal Silicon with Electron Conductivity

Using scanning electron microscopy, the structures of the surface and internal regions of porous silicon obtained by anodizing heavily doped plates of single-crystal silicon with electron conductivity in a hydrofluoric acid solution at different current densities were studied. It is found that the porous silicon surface has dark gray and light gray pores, which differ in size and surface distribution density. Dark gray pores possess larger sizes, and their density is about 5–10 times less than that of light gray pores. Based on the cross-section imagery, it is shown that light gray pores correspond to underdeveloped channels of small depth, while dark gray pores are the entrance points of deep bottle-shaped channels passing from the surface into the depth of the silicon wafer. The equivalent diameters of light gray pores on the surface of porous silicon are 12–15 nm and are practically independent of the anodic current density. At the same time, the equivalent diameters of dark gray pores and average distances between their centers increase linearly from 15 to 35 nm on the surface and from 35 to 120 nm in the volume of porous silicon when the current density is increased from 30 to 90 mA/cm2. The average thickness of silicon skeleton elements is about 3 nm on the surface and increases to 5–6 nm in the volume. By setting the density of the anode current, it is possible to obtain layers of porous silicon with different structural parameters. The obtained research results have practical significance for the formation of composite materials based on porous silicon, which can be used as a porous matrix for the deposition of metals and semiconductors.

A novel wafer defocus measurement method for spot-scanning imaging system using laser triangulation

Abstract For spot scanning dark-field scattering technology, the defocus caused by the change in wafer surface height decreases the defect detection rate and size measurement repeatability. The demand for accurately and rapidly measuring the wafer surface height online is becoming increasingly urgent. The defect detection system integrates scattering, reflection, film thickness, and topography defect detection channels. The integration of laser-triangulation-based defocus measurement into the bright-field optical path is proposed. The laser beam is directed onto the surface of the wafer, and the reflected light is transmitted through a lens onto the photosensitive surface of a four-quadrant detector. This detector captures both the strength and position of the reflected signal simultaneously. In this paper, a triangulation-modified model is established to obtain the height of each inspection spot on the wafer surface through the position signal of the reflected image. When the signal-to-noise ratio of the simulated reflection image position is 20 dB, the signal-to-noise ratio of the height measurement resolved by the triangulation-modified model is 41 dB, and the measurement error is less than 0.2 μm, indicating that the model has a noise suppression effect. The spot-scanning imaging system is established, and the height measurement results of the triangulation measurement model are verified using a laser interferometer. Within the travel range of 69 μm, the system has a measurement accuracy better than ±1 μm and a measurement repeatability better than ±0.2 μm, which meet the measurement requirements of the spot-scanning imaging system. The system is utilized for defect detection and defocus measurement of the wafer surface, along with the motion mechanism, to accurately and rapidly obtain the height distribution of the wafer surface.

Revealing Spatial Molecular Heterogeneity of High-Density Biofunctionalized Surfaces Using DNA-PAINT.

The quantification and control of molecular densities and distributions on biofunctionalized surfaces are key for enabling reproducible functions in biosciences. Here, we describe an analysis methodology for quantifying the density and spatial distribution of high-density biofunctionalized surfaces, with densities in the order of 102-105 biomolecules per μm2 area, in a short measurement time. The methodology is based on single-molecule DNA-PAINT imaging combined with simulation models that compensate for lifetime and spatial undersampling effects, resulting in three distinct molecule counting methods and a statistical test for spatial distribution. The analysis methodology is exemplified for a surface with ssDNA affinity binder molecules coupled to a PLL-g-PEG antifouling coating. The results provide insights into the biofunctionalization efficiency, yield, and homogeneity. Furthermore, the data reveal that heterogeneity is inherent to the biofunctionalization process and shed light on the underlying molecular mechanisms. We envision that DNA-PAINT imaging with the developed analysis framework will become a versatile tool to study spatial heterogeneity of densely biofunctionalized surfaces for a wide range of applications.

Charge‐Sign‐Independent Separation of Mono‐ and Divalent Ions With Nanofiltration Membranes

AbstractAchieving precise selective separation of monovalent and divalent cations, as well as anions, is vital yet challenging in practical applications involving complex component treatments. Current membranes are typically effective for separating either cation pairs or anion pairs. To address this issue, a straightforward strategy for fabricating a nanofiltration (NF) membrane is developed that selectively permeates monovalent ions. This study focused on neutralizing the surface charge and tuning the pore size distribution of the polyamide membranes through a secondary interfacial polymerization using a zwitterionic copolymer consisting of 2‐methacryloyloxyethyl phosphorylcholine and 2‐aminoethyl methacrylate hydrochloride. The optimized NF membrane prepared in this study, with a near‐neutrally charged membrane surface and appropriate pore size distribution, demonstrates favorable performance in precisely separating monovalent and divalent ions, irrespective of the ion charge sign. The optimum NF membrane features high selectivity for both Cl−/SO42− (93) and Li+/Mg2+ (67) ion pairs, along with high water permeance of 8.5 L m−2 h−1 bar−1, making it competitive with many reported membranes. This study offers new insights into the ion‐selective mechanisms of polyamide membranes for monovalent/divalent ions and may guide the development of advanced membranes with single‐solute selectivity.

A critical evaluation of platinum deposition techniques for hydrogen production in microbial electrolysis cells

Despite its high cost, Pt is the usual catalyst for hydrogen production in the cathode of Microbial Electrolysis Cells (MECs). Its effectiveness depends not only on the amount deposited but also on the availability and distribution of Pt nanoparticles on the cathode surface. This work provides a comprehensive study of the effectiveness of the Pt coating with five deposition techniques: spray, electrospray, brush painting, doctor blade and sputtering. The performance of the cathodes was studied with different Pt loadings by monitoring the current intensity and H2 production in MECs. Furthermore, cathodes were characterized morphologically using scanning electron microscopy together with energy-dispersive X-ray spectroscopy to study their Pt surface distribution and composition. Sputtering was initially discarded due to Pt detachment. When using the same amount of Pt (0.50 mg Pt cm−2), the highest current density was obtained for electrospray (2.0 mA cm−2), followed by spray (1.9 mA cm−2), brush painting (1.6 mA cm−2) and doctor blade (1.2 mA cm−2). Hence, electrospray improved 20 % the results obtained by the default method of brush painting. Electrospray and spray provided better performance because of the direct deposition of Pt on the carbon fibres creating a compact Pt layer on the electrode surface. Furthermore, it was observed that the cell performance decreased significantly with decreasing amount of Pt per cm2, observing the best performance with the highest Pt load tested (0.5 mg Pt cm−2) regardless of the deposition technique.

Piecewise approximation and local differential compensation of contact stress distribution of workpiece surface in robotic belt grinding

Piecewise approximation and local differential compensation of contact stress distribution of workpiece surface in robotic belt grinding

Three-Dimensional Site Response Analysis of Clay Soil Considering the Effects of Soil Behavior and Type

To understand changes in bedrock motion at the ground surface, frequency effects, and spatial distribution within the soil, it is important to look at how a site responds to earthquakes. This is important for soil–structure interaction in structural and geotechnical earthquake engineering. This study deals with the effect of classifying clays according to shear wave velocity (stiff/medium/soft) and nonlinearity in behavior (linear/nonlinear) on the analysis of the site response. A 3D soil model with a combination of free fields and quiet boundaries and advanced constitutive models for soil to obtain accurate results was used to conduct this study. A strong TABAS earthquake was used to excite the compliant base of the model after converting the velocity record of TABAS to an equivalent surface traction force using a horizontal force–time history proportional to the velocity–time history. This study reveals that the site response analysis is affected by the type of clay soil and the soil material behavior, with soft clay soil causing higher PGV and PGV values in the linear case and lower values in the nonlinear case due to soil yielding, which causes soil response attenuation. This results in extremely conservative and expensive building designs when linear soil behavior is adopted. On the other hand, the applied earthquake exhibits greater attenuation at longer frequencies and greater amplification at mid and short frequencies. However, at frequencies near the applied earthquake frequency, neither attenuation nor amplification occurs. Furthermore, nonlinear soil behavior is crucial for soil evaluation and foundation design due to higher octahedral shear strain and settlement values, especially in softer soils, resulting from extensive plastic deformation.

Characterization of Ni-Cu multilayers deposition on low carbon steel substrate using electroplating technique

Abstract Low carbon steel is widely used in oil and gas applications. In this research, multilayers of Nickel (Ni) and Copper (Cu) were deposited on a low carbon steel substrate using the electroplating process (ELP). Initially, a layer of Ni was coated, followed by a layer of Cu. ELP was implemented using water bath containing (300 g/l) of NiSO4.6H2O, (30 g/l) of (NiCl2.6H2O), (40 g/l) of H3BO3 and (30 g/l) of (NaCN), (30 g/l) of (CuCN), (10 g/l) of (NaOH.6H2O). First bath parameters were temperature is (59 - 60 °C), current density in the range of (3-5 A/dcm2), voltage was holed at (8 V) for Ni, and temperature was between (50-51 °C), current density in the range of (1-2 A/dcm2), voltage was holed at (4 V), while the plating time (10 minutes) for both Ni and Cu. The results refer to Ni, Cu, and Ni &amp; Cu ELP thicknesses 3, 4.77 and 6.75 μm respectively. Metallurgical tests were achieve including the micro hardness of ELP, Vickers micro hardness results showed improvement in hardness values compared, with steel substrate, and in the presence of Ni, Cu, Ni+Cu layers, 322, 581, 479, and 562 Hv respectively. The roughness was measured using surface roughness measurement device. The average surface roughness (Ra) depicted satisfying values as a result of Ni layer coating, which gave uniform surface distribution with Ra 0.363 μm. X-ray diffraction (XRD) test examinations serve as strong evidence for the presence of Ni and Cu in the internal and external finish layers, respectively. Corrosion examinations were carried out in seawater solution (3.5 g NaCl) the corrosion behavior tends to be more resistance, with layers of Ni, and Cu in sea water environment, which is considered an important criterion to increase the part life.