Target Material Properties Research Articles

Thermodynamic Modeling of CO2 Separation Systems with Soluble, Redox-Active Capture Species

Electrochemical approaches hold promise for energy-efficient and modular carbon dioxide (CO2) separation systems that can make direct use of renewably generated electricity. Here, we employ a thermodynamic modeling approach to estimate the upper performance bounds of CO2 separation processes that use soluble, redox-active capture species. We contemplate the impact of tunable molecular and electrolyte properties on the thermodynamic and faradaic efficiencies of four characteristic system configurations. We find a trade-off between these efficiency metrics and propose a new metric, the combined efficiency, that can be used to further explore this trade-off and identify desirable property sets that balance energy and materials requirements. Subsequently, we determine effective CO2 binding affinities of redox-active capture molecules and demonstrate how these values are dependent upon molecular properties, system format, and operating conditions. Overall, this analytical framework can help guide molecular discovery and electrolyte engineering in this emerging field by providing insight into target material properties.

Flow Velocity and Sand Loading Effect on Erosion–Corrosion during Liquid-Solid Impingement on Mild Steel

The presence of CO2, sand, and water in oil and gas reservoirs causes erosion–corrosion leading to material degradation in pipelines and fluid handling equipment that results in increasing maintenance and repair costs and a decrease in production. While the weight loss caused by erosion–corrosion is known to depend on flow velocity, angle of impact, sand loading and size and target material properties, field operators often limit the flow rate based on a critical corrosion velocity to protect the equipment. This study investigates the effects of sand loading and flow velocity on weight loss associated with erosion–corrosion in a mild steel sample using a submerged impingement jet. The weight loss by erosion, corrosion and their interaction for a flow velocity range of 10 m/s to 20 m/s and sand loading range of 300 mg/L to 600 mg/L, in a seawater environment, are presented. The results showed that the weight loss by pure erosion and erosion–corrosion interaction increases linearly with jet velocity and sand loading, and that erosion is dominant in all cases except at low velocity and sand loading. The scanning electron microscope (SEM) images after impingement tests were analyzed. In addition, correlations for the velocity and sand loading were derived using the design of experiment method (DOE).

Determination of mechanical properties from sharp dynamic indentation

In this study, a dynamic indentation test method based on the split Hopkinson pressure bar is proposed to obtain the dynamic parameters of Ludwik power law constitutive, namely, Young’s modulus E, strength coefficient K, and strain hardening index n by analyzing dynamic indentation load-indentation depth curve obtained from the theories relating to the Hopkinson pressure bar. The important parameters, namely, loading curvature C and transformation factor [Formula: see text], are invoked to examine the dynamic indentation response results in a wide range of target material parameters. Finite element calculation results are processed through simulation of dynamic indentation response with broad material parameters. Furthermore, the analytical method is used to fit simulation results to obtain the analytical equations for elastic–plastic parameters and curvature parameters for the subsequent analysis. The analytical equation of forward model to predict dynamic indentation response parameter–loading curvature C of a known material is proposed. Then, the elastic–plastic parameters of unknown materials (according to Ludwik power law) are obtained by substituting the dynamic indentation response parameters into an inverse analytical equation under the two types of half-cone angle indenters. The method is verified by other typical materials, which shows that the dynamic indentation test based on the split Hopkinson pressure bar can obtain sufficient conditions to obtain dynamic mechanical properties of target materials.

Design of wood-like metallic material using metal sheet architecture

Abstract This study proposed a new metal-based material design with a modulus of elasticity and thermal conductivity comparable to that of wood by architecturing of metal sheets. The proposed new material is designed in a form in which metal sheets of the same shape with beads are repeatedly stacked. In order to find a design with the target modulus of elasticity and thermal conductivity values, designs were derived using the Design of Experiment (DOE) and the material properties were predicted accordingly. For the prediction of material properties designed in the shape of a metal sheet architecture, finite element analysis combined with the homogenization method was used in consideration of the repeatability of the material microstructure. The reliability of the prediction of material properties based on the finite element analysis using a unit cell was verified by comparison with the results obtained from the compression test and the temperature wave method for the specimen. By analysing the modulus of elasticity and thermal conductivity data corresponding to the designs derived by DOE, we evaluated the effect of the design variables of the metal sheet architecture on the material properties. In addition, we investigated whether the material properties comparable to wood or leather were included within the derived design domain, and presented detailed design data of a metal sheet architecture that provides targeted material properties. It can be inferred from this study that the use of architecturing of metal sheets enables the development of new metal-based materials that can simulate the properties of other materials while utilizing the advantages of fire resistance and recyclability inherent in metals.

Erosion of polymers and polymer composites surfaces by particles

Surface erosion due to solid particle impact is a major concern in engineering applications of handling solid-particulate flow. A semi-empirical model is developed for numerical erosion simulation of polymers and polymer composites. The novelty of the developed model is the correct capturing of the angle of maximum erosion for different erosion modes of polymeric materials and relating it to measurable mechanical properties of the target materials. The model incorporates both the material removal due to elastic–plastic collision of the particles at oblique and normal impact angles. The oblique impact model is derived for ploughing and fracture governed mechanisms of material removal. A simplified correlation is used to consider the relative effect of each mechanism on the total erosion at oblique impact angles. The model indicates the variation in velocity exponent to the mechanism of material removal. The theoretically derived model for single-particle impact is correlated to the available experimental results of multi-particle impacts through the empirical coefficients. The predictions are in good agreement with the extensive literature data for polymers and polymer composites. Further, to propose a single model of erosion for polymer and its composite, the relationship between the empirical coefficients in the developed model and the target material properties is established.

Energy distributions of the particles sputtered by gas cluster ions. Experiment and computer simulation

We present experimental studies and computer simulations of the energy distributions of the particles sputtered from copper and molybdenum with gas cluster ions. Both experimental and simulated distributions were found to be narrower than ones known for atomic ion sputtering. It was shown that the distributions of sputtered atoms obtained by molecular dynamics simulations can be well described in frames of the thermal spike theory. For a given cluster energy, its size and the target material properties determine the parameters of the distributions. Including into consideration sequential cluster impacts on the target surface resulted in changes both in energy and angular distributions of sputtered matter and as well in total sputtering yield. Experimentally measured distributions well matched the ones simulated in “sequential” mode.

Effect of annealing temperature on slurry erosion resistance of ferritic X10CrAlSi18 steel

In the present work, the slurry erosion tests were carried out to investigate the influence of heat treatment on slurry erosion process of ferritic X10CrAlSi18 stainless steel using a slurry pot test rig. X10CrAlSi18 stainless steel was tested in as-received condition and after annealing at three different temperatures: 600 °C, 800 °C and 1000 °C. Degradation of materials due to slurry erosion depends on many factors connected with fluid flow conditions, properties of target material and erodent characteristics. In this case, factors related to the properties of the eroded material such as microstructure, grain size, work hardening, hardness played an important role. The heat treatment decreased hardness of this steel and increased erosion resistance. Microstructure was one of the most important parameters influencing the slurry erosion process of tested materials. X10CrAlSi18 stainless steel after annealing at 600 °C with fine-grained microstructure and the deepest of work hardening layer obtained the best resistance to slurry erosion. Heat treatment contributed to approximately 55%, 23% and 41% decrease in mass loss compared to steel in as-received condition. After slurry erosion tests craters, fracture, ridges and flakes were observed on the eroded surface. Furthermore, to identify the dominant mechanism of erosion, the erosion efficiency parameter was used, η.

EFFECTS OF VOLUME OF CARBON NANOTUBES ON THE ANGLED BALLISTIC IMPACT FOR CARBON KEVLAR HYBRID FABRICS

Investigations of the angled ballistic impact behavior on Carbon Kevlar® Hybrid fabrics with assorted volumes of carbon nanotubes (CNTs) into epoxy are presented. The ballistic impact behavior of the epoxy composites with/without CNTs is compared. Individual impact studies are conducted on the composite plate made-up of Carbon Kevlar Hybrid fabrics with diverse volumes of CNTs. The plate was fabricated with eight layers of equal thickness arranged in different percentages of CNTs. A conical steel projectile is considered for a high velocity impact. The projectile is placed very close to the plate, at the centre and impacted with sundry speeds. The variation of the kinetic energy, the increase in the internal energy of the laminate and the decrease in the velocity of the projectile with disparate angles are also studied. Based on the results, the percentage of CNTs for the ballistic impact of each angle is suggested. The solution is based on the target material properties at high ballistic impact resistance, the inclined impact and the CNT volumes. Using the ballistic limit velocity, contact duration at ballistic limit, surface thickness of target and the size of the damaged zone are predicted for fabric composites.

AMP2: A fully automated program for ab initio calculations of crystalline materials

Ab initio calculations based on the density functional theory (DFT) become a vital tool in material science for understanding and predicting material properties. However, DFT calculations involve several parameters and procedures that call for deep understanding on underlying theories and preceding knowledge on certain properties of target materials. Such technicalities cost a significant amount of human time and expose practitioners to mistakes. Here, we introduce a fully automated package for DFT calculations, automated ab initio modeling of materials property package (AMP2), which aims to produce key DFT properties of crystalline materials with essentially no user intervention except for initial structural information. This is achieved through algorithms that automatically determine various technical parameters and make self-decisions during computational workflow. As results, AMP2 is material-agnostic and provides a highly accurate band structure, band gap, effective mass, density of states and dielectric constant for the given material. Notably, the package finds the antiferromagnetic ground state by applying a genetic algorithm to effective Ising models. AMP2 also addresses band-gap underestimation in semilocal functionals with help of a hybrid functional, thereby producing a more accurate band gap, even if the material turns out to be metallic within the semilocal functional. We believe that the present package will significantly expand usage of DFT calculations by making them more accessible. Program summaryProgram Title: AMP2CPC Library link to program files: http://dx.doi.org/10.17632/5rdw9jv5vp.1Licensing provisions: GPLv3Programming language: PythonNature of problem: Conducting abinitio calculation under a fully automated protocol to obtain crystalline propertiesSolution method: Construct workflow to estimate material properties using the density functional theory. Ising model and genetic algorithm are used for identifying magnetic spin ordering.

The optimal nose shape of a projectile penetrating into targets described by a locked hydrostat and a linear shear failure relationship

The present paper analyzes the optimal nose shape of an axisymmetric rigid projectile which penetrates into a thick target. The optimal projectile nose shape is defined as the shape on which the minimum resistive force is developed in its interaction with the target. This resistive force sums up the contributions of the contact interaction pressures acting on the projectile nose envelope. The interaction pressure between the projectile and the target depends on the projectile total mass, on the target material properties, the projectile motion characteristics and the projectile geometrical parameters and especially on the unknown nose shape function and its derivatives. A variational analysis, aiming at minimization of the resistive force functional using the Euler-Poisson equation is carried out. In the general case, the problem of the optimal nose shape of an axisymmetric rigid projectile which penetrates into a semi-infinite target can be solved only by numerical methods. Using simplified constitutive relationships may allow a closed form solution of the optimal nose shape. This paper considers a locked hydrostat and a linear shear failure-pressure relationship that may enable a simplified representation of targets like soil and concrete, and allow a closed form solution of the optimal nose shape.It is confirmed that the Euler-Poisson equation is only a necessary condition for the existence of an extremum of the functional and therefore the obtained solution should be examined whether it actually yields a minimum resistive force and maximal penetration depth.To verify the optimal solution, the calculated deceleration and penetration depth time histories of the optimal nose shape projectiles are compared with calculated and experimental results of similar projectiles with an ogive nose, and the efficiency of the optimal nose is confirmed.

Novel synthesis of BiVO4 using homogeneous precipitation and its enhanced photocatalytic activity

The improvement of the photocatalyst performance with reducing the production cost is still the most important concern for finding target material properties and the possibility of mass production. Herein, we report a novel synthesis of BiVO4 photocatalyst by homogeneous precipitation. Different surfactants such as polyvinylpyrrolidone (PVP), ethylene glycol (EG), cetyltrimethylammonium bromide (CTAB), and sodium dodecylbenzene sulphonate (SDBS) were added to assist the crystal orientation. XRD, SEM, Raman, and DRS were used to evaluate the crystal orientation of the as-synthesized BiVO4 samples. The XRD revealed the purity of the produced samples except for SDBS that produced a mixture (tetragonal /monoclinic) phase. The Raman analysis confirmed that the PVP surfactant has the smallest V–O bond length that led to the lowest bandgap 2.17 eV. The photoelectrochemical results revealed that there is a decrease in the electron-hole recombination rate as shown from electrochemical impedance spectroscopy (EIS) data, as well as swelling of band pinning of the Fermi energy edge toward the negative direction according to the Mott-Schottky (MS) curve. These impacts are due to the different facets possessing truncated bipyramid-like shape which is created via PVP surfactant. These variations enhanced the photodegradation of methylene blue (MB) dye as a wastewater module.

The optimal geometry of sub-grain microstructural features in 3D printed alloys for improving the strength and toughness

Mechanical properties of 3D printed alloys are highly related to their microstructural properties. While in the past few years a large effort has been dedicated to find the relationship between the processing parameters and mechanical properties, a systematic methodology which considers the effect of microstructure on the mechanical properties is still missing. In this paper, a parametric simulation-based study is performed to investigate how the geometry of cells, sub-grain microstructures that form during 3D printing of alloys, affects the strength and toughness of the material. In this paper, a parametric study is performed to investigate how the geometry of cells, sub-grain microstructures that form during 3D printing of alloys, affects the strength and toughness of the material. Our results can be used to find out the optimum geometry of the cells for any specific loading condition, and the targeted material properties (strength or toughness). The previously reported works which define the interconnection between the processing parameters and the microstructure can be then utilized to find the processing parameters which can be used to 3D print the alloy with those optimum mechanical properties. Our computational results can also be considered as a guide for the community for designing processing parameters which can be used to modify the 3D printing strategies for fabricating metals with the microstructures which correspond to the optimal mechanical properties.

Effect of Lode angle incorporation into a fracture criterion in predicting the ballistic resistance of 2024-T351 aluminum alloy plates struck by cylindrical projectiles with different nose shapes

The aim of the present paper is to evaluate the effect of Lode angle incorporation into a fracture criterion when predicting the ballistic resistance of 2024-T351 aluminum alloy plates struck by cylindrical projectiles with different nose shapes through finite element (FE) simulations. To this end ballistic tests in the sub-ordnance impact velocity range were firstly conducted on 9.94 mm thick 2024-T351 aluminum alloy plates using cylindrical projectiles with blunt, hemispherical and ogival nose shapes, a nominal diameter of 12.66 mm, and a nominal mass of 50 g. Ballistic limit velocities (BLVs) for different projectile-target pairs considered were calculated using initial vs. residual velocity data obtained in the experiments. Subsequently FE simulations of the conducted experiments were performed with SIMULIA Abaqus software. In those simulations Johnson–Cook yield criterion with a modified strain hardening law was accompanied with either the Lode-independent Johnson–Cook (JC) fracture criterion or the Lode-dependent modified Mohr–Coulomb (MMC) fracture criterion to describe target material properties. Finally, the predicted ballistic resistance and fracture patterns of the targets were compared with those observed in the experiments. It was found that in the simulations with the Lode-independent JC fracture criterion the BLVs of the targets were overestimated by 18.0–35.1% depending on the projectile nose shape. In the simulations with MMC fracture criterion the BLVs predictions were substantially improved, so that the difference with the experimental results did not exceed 9.0%. Targets failure mechanisms obtained in the simulations with MMC fracture criterion also better match the experiments than those predicted with JC fracture criterion. In the simulations with MMC fracture criterion the targets impacted by the projectiles with blunt and hemispherical noses failed through shear plugging, whereas ogive-nosed projectiles caused ductile hole enlargement and target fragmentation due to its rear side radial fracture and bending of formed short petals with their eventual shear fracture. At the same time the simulations with JC fracture criterion predicted shear plugging for the blunt-nosed projectiles, very small conical plug ejection and target fragmentation due to discing for the hemispherical-nosed projectiles, and ductile hole enlargement for the ogive-nosed projectiles. A detailed analysis of the failure process revealed that in the case of the ogive-nosed and hemispherical-nosed projectiles, respectively, the ductile hole enlargement occurs during the initial stage of the impact and subsequent through-thickness fracture develops causing either fragmentation of the target or its shear plugging failure. The Lode-independent JC fracture criterion overestimates a material fracture strain under shear, thus leading to poor prediction of 2024-T351 aluminum alloy targets ballistic performance in the numerical simulations.

Estimation of Unknown Parameters of the Equivalent Electrical Model During an Eddy Current Test

This article presents a method to estimate unknown parameters in an eddy current detection system: the magnetic coupling coefficient $k$ between the probe coil and the surface of a conductive sample and also a constant $C$ dependent on the material and geometrical properties of the conductive target. These parameters are defined from the analysis of the electrical equivalent model of the measurement system. Thereby, the liftoff from an ECT probe can be estimated during a scanning procedure by estimating $k$ . The presented method depends on the input impedance of the inductive probe stimulated by a power source with an appropriate range of frequencies. The self-inductance as well the intrinsic resistance of the probe needs to be measured in advance. While the input impedance is monitored, the magnetic coupling coefficient $k$ and constant $C$ are continuously estimated with a recursive least squares method. A theoretical analysis is presented and supported by experiments conducted with three different conductive metal samples: aluminum, copper, and brass. The results presented good agreement with the reference and estimated parameters $C$ and $k$ as well as the liftoff between the probe and the conductive target.

Dielectric and Emissive Properties of Sorghum (Jowar) Vegetation at C-Band Microwave Frequency

Abstract Microwave interaction with earth resources like soil and vegetation provides useful information for remote sensing techniques. Such interaction is mainly governed by a complex dielectric property of target material. This paper reports on laboratory measurements of complex dielectric constant of sorghum vegetation (leaves) at room temperature (30°C), at C-Band microwave frequency. Von Hippel (shorted waveguide) method is used to conduct the measurements. The measurements were performed for freshly cut sorghum leaves as a function of moisture content by using automated C-Band microwave bench set up with movable reflector. The least square fitting technique is used to calculate dielectric constant (e'), dielectric loss (e'') and errors in their measurements. Emissivity and radiometric brightness temperature is estimated from measured dielectric properties at different angle of incidence for dry and moist sorghum leaves using Fresnel equations. This study is useful for interpretation of microwave remote sensing of vegetation and applications specifically in agriculture

Target properties – Plasma dynamics relationship in laser ablation of metals: Common trends for fs, ps and ns irradiation regimes

Better understanding of complex relationships between laser-produced plasma dynamics and ablation target material properties is key for optimization of numerous technological and analytical applications. Continuing a previous work [Irimiciuc et al., Appl. Surf. Sci. 417 (2017) 108–118] which proposed empirical laws for some of these relationships (in femtosecond irradiation regime), we present here a systematic study on several metallic targets (Al, Cu, Mn, Ni, Ti, Zn) irradiated by nanosecond, picosecond and femtosecond laser pulses. The experimental approach is based on complementary diagnostics, with the implementation of both electrical and optical techniques for transient plasma characterization. The empirical equations previously reported for femtosecond ablation pulses are now extended to the picosecond and nanosecond regimes.

The Seismic Signatures of Recently Formed Impact Craters on Mars.

We investigated the seismic signatures of recent impact crater clusters on Mars that would be recorded by the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) seismometers. We used a database of 77 measured and dated impact sites, with craters with diameters between 2.1 and 33.8 m, along with inferred impact angle, bolide trajectory, and varying target material properties to empirically scale for the momentum, expected seismic source function, and radiation pattern of impacts. The impact source is simulated in a local 3-D finite difference wave propagation code and coupled to teleseismic distances by scaling the spectra of 1-D global synthetic seismograms. We use the InSight seismometer noise floors to estimate detectability of impact(s) across azimuth and distance. Our experiments reveal that impact clusters have a higher peak corner frequency resulting from energy contributed by smaller craters to the power spectrum. We also find that the time separation between individual impacts in a cluster is small (< 10-15 milliseconds) and a require a seismometer closely situated to the source (< 10 km) and a high sampling rate (> 100 Hz) to resolve individual impacts within the cluster. Two of the clusters in our database (> 20 m effective diameter) would have been detectable by InSight, with the assumptions that the martian background noise and seismic attenuation are both low. Joint detection of surface changes from newly formed crater(s) in images and by InSight will provide precise source locations that are crucial for constraining the internal structure of Mars.

Benchmarking impact hydrocodes in the strength regime: Implications for modeling deflection by a kinetic impactor

The Double Asteroid Redirection Test (DART) is a NASA-sponsored mission that will be the first direct test of the kinetic impactor technique for planetary defense. The DART spacecraft will impact into Didymos-B, the moon of the binary system 65803 Didymos, and the resulting period change will be measured from Earth. Impact simulations will be used to predict the crater size and momentum enhancement expected from the DART impact. Because the specific material properties (strength, porosity, internal structure) of the Didymos-B target are unknown, a wide variety of numerical simulations must be performed to better understand possible impact outcomes. This simulation campaign will involve a large parameter space being simulated using multiple different shock physics hydrocodes. In order to understand better the behaviors and properties of numerical simulation codes applicable to the DART impact, a benchmarking and validation program using different numerical codes to solve a set of standard problems was designed and implemented. The problems were designed to test the effects of material strength, porosity, damage models, and target geometry on the ejecta following an impact and thus the momentum transfer efficiency. Several important results were identified from comparing simulations across codes, including the effects of model resolution and porosity and strength model choice: 1) momentum transfer predictions almost uniformly exhibit a larger variation than predictions of crater size; 2) the choice of strength model, and the values used for material strength, are significantly more important in the prediction of crater size and momentum enhancement than variation between codes; 3) predictions for crater size and momentum enhancement tend to be similar (within 15‐20%) when similar strength models are used in different codes. These results will be used to better design a modeling plan for the DART mission as well as to better understand the potential results that may be expected due to unknown target properties. The DART impact simulation team will determine a specific desired material parameter set appropriate for the Didymos system that will be standardized (to the extent possible) across the different codes when making predictions for the DART mission. Some variation in predictions will still be expected, but that variation can be bracketed by the results shown in this study.

Waterjet Erosion Model for Rock-Like Material Considering Properties of Abrasive and Target Materials

In this study, we investigated the characteristics of abrasive erosion considering the material properties of abrasives and targets. An abrasive particle erosion model considering energy transfer due to hardness differences was developed based on energy conservation using the correlation between volume removal and effective kinetic energy. To obtain the effective erosion kinetic energy of an abrasive, an acceleration model was derived for the abrasive particles, including terms describing the properties of the abrasive and fluid. The applicability of the suggested model was verified by comparing the brittle erosion results obtained using a previous theoretical approach to those of the present numerical analysis. The results obtained using the developed model exhibited good qualitative agreement with the brittle material erosion results. By evaluating acceleration and the erosion characteristics of an abrasive, the erosion performance could be predicted and optimized.

Homogenization and localization of imperfectly bonded periodic fiber-reinforced composites

An elasticity-based micromechanics model is derived analytically to investigate the homogenized and localized responses of unidirectional composites with imperfect interfaces. To mimic the perturbation of the inclusion positioning caused by the consolidation process, an arbitrarily parallelogram-shaped repeating unit cell (RUC) is developed with periodic boundary conditions. Different from the finite-element/volume approaches which solve a boundary-value problem in the discretized domain, the present work avoids the complicated mesh discretization and instead adopts the Trefftz concept that employs the complete elastic solutions with unknown coefficients to represent the internal trial displacement/stress fields. The solutions of the unknown coefficients are obtained by applying the flexible separation relations along the fiber/matrix interface that govern the interfacial traction reciprocities and displacement discontinuities, as well as the periodic balanced variational principle at the circumference of microstructures. The homogenization equations are then applied to generate the effective properties of composite materials with different architectures over a wide range of fiber volume fractions. In addition to validating the effective properties and underpinning stress fields against other micromechanical techniques in the literature, new results are generated extensively aiming at demonstrating the effects of the interfacial stiffness, radius of fiber and shape of the unit cell on the homogenized and localized composite responses. The analytical framework developed in this communication also facilitates the identification of the interfacial stiffness that minimizes the difference between the effective moduli and targeted material properties through the incorporation of Particle Swarm Optimization algorithm.