Bulk Component Research Articles

Role of crystalline orientations and additive layers on bulk tensile response of wire-arc directed energy deposited (WDED) single phase titanium

A significant challenge in improving metal-based wire-arc directed energy deposition (WDED) for additive manufacturing is the lack of knowledge about microstructure evolution and its correlation with layer-wise plastic response and bulk tensile behavior. For the first time, this paper establishes the role of crystalline orientation, dislocation densities, and layer-by-layer strength on the anisotropy of bulk uniaxial tensile deformation in commercially pure titanium (cp-Ti) processed by WDED. An integrated approach that combines microscopy, spectroscopy, millimeter-scale indentation and centimeter-scale uniaxial tensile techniques is adopted. The variation in thermal cycles during WDED results in a higher grain orientation spread greater than 5° in the longitudinal direction (LD) parallel to arc motion compared to about 4° along the normal direction (ND) of additive buildup. Similarly, the statistically stored dislocation density in LD, 1.8 x 1016 m−2, is double that in ND, 0.9 x 1016 m−2. These factors result in a greater strain localization in the LD than in ND. The higher strain localization results in plastic anisotropy manifested as material buildup and ductility, which are 40 μm and 33 % higher in ND than in LD. On the other hand, the monolithic macrostructure and absence of weak points at layer interfaces of the cp-Ti component led to comparable yield and ultimate tensile strengths across the individual layers and the bulk component at 311–328 MPa and 369–385 MPa, respectively. These properties are about 90 % of those in conventionally cast commercially cast titanium. Thus, the comprehensive understanding of titanium's nuanced isotropic strength and anisotropic ductility constitutes a major step in advancing WDED as a large-scale additive manufacturing technology and establishing a standardized database of mechanical properties.

Evidence for bipolar explosions in Type IIP supernovae

Aims. Recent observations of core-collapse supernovae (SNe) suggest aspherical explosions. Globally, aspherical structures in SN explosions are thought to encode information regarding the underlying explosion mechanism. However, the exact explosion geometries from the inner cores to the outer envelopes are poorly understood. Methods. Here, we present photometric, spectroscopic, and polarimetric observations of the Type IIP SN 2021yja and discuss its explosion geometry in comparison to those of other Type IIP SNe that show large-scale aspherical structures in their hydrogen envelopes (SNe 2012aw, 2013ej and 2017gmr). Results. During the plateau phase, SNe 2012aw and 2021yja exhibit high continuum polarization characterized by two components with perpendicular polarization angles. This behavior can be interpreted as being due to a bipolar explosion, where the SN ejecta is composed of a polar (energetic) component and an equatorial (bulk) component. In such a bipolar explosion, an aspherical axis created by the polar ejecta would dominate at early phases, while the perpendicular axis along the equatorial ejecta would emerge at late phases after the photosphere in the polar ejecta has receded. Our interpretation of the explosions in SNe 2012aw and 2021yja as bipolar is also supported by other observational properties, including the time evolution of the line velocities and the line shapes in the nebular spectra. The polarization of other Type IIP SNe that show large-scale aspherical structures in the hydrogen envelope (SNe 2013ej and 2017gmr) is also consistent with the bipolar-explosion scenario, although this is not conclusive.

Modelling internal erosion using 2D smoothed particle hydrodynamics (SPH)

This paper presents a stabilised multi-phase smoothed particle hydrodynamics (SPH) model applicable to seepage-induced internal erosion and the resulting deformation in soils. Based on the continuum mixture theory, a new single-layer SPH model in the u-w-p formulation is derived for the mathematical description of the erodible porous material. A new modified constitutive model is formulated to account for the influence of erosion on the mechanical behaviour of soils. Extensions of a first-order consistent boundary condition as well as the diffusion algorithm for hydro-mechanical coupling in SPH are also proposed to accommodate the analysis of erosion-transport process. A novel viscous dissipation term is designed to mitigate the numerical instability commonly encountered in coupled problems. In contrast to existing stabilisation terms in the SPH literature, which operate on both the bulk component and shear component, this new stabilisation term offers the possibility to increase the dissipation of unphysical oscillation due to the shear deformation. The proposed method is validated through a series of benchmark tests. The results demonstrate the effectiveness of the proposed approach in addressing the coupled problem in porous materials involving multi-phase flow, phase interaction/transfer, and large deformation with enhanced accuracy, stability, and robustness.

Frequency beating and damping of breathing oscillations of a harmonically trapped one-dimensional quasicondensate

We study the breathing (monopole) oscillations and their damping in a harmonically trapped one-dimensional (1D) Bose gas in the quasicondensate regime using a finite-temperature classical field approach. By characterising the oscillations via the dynamics of the density profile's rms width over long time, we find that the rms width displays beating of two distinct frequencies. This means that 1D Bose gas oscillates not at a single breathing mode frequency, as found in previous studies, but as a superposition of two distinct breathing modes, one oscillating at frequency close to $\simeq\!\sqrt{3}\omega$ and the other at $\simeq\!2\omega$, where $\omega$ is the trap frequency. The breathing mode at $\sim\!\sqrt{3}\omega$ dominates the beating at lower temperatures, deep in the quasicondensate regime, and can be attributed to the oscillations of the bulk of the density distribution comprised of particles populating low-energy, highly-occupied states. The breathing mode at $\simeq\!2\omega$, on the other hand, dominates the beating at higher temperatures, close to the nearly ideal, degenerate Bose gas regime, and is attributed to the oscillations of the tails of the density distribution comprised of thermal particles in higher energy states. The two breathing modes have distinct damping rates, with the damping rate of the bulk component being approximately four times larger than that of the tails component.

Polymer design for solid-state batteries and wearable electronics.

Solid-state batteries are increasingly centre-stage for delivering more energy-dense, safer batteries to follow current lithium-ion rechargeable technologies. At the same time, wearable electronics powered by flexible batteries have experienced rapid technological growth. This perspective discusses the role that polymer design plays in their use as solid polymer electrolytes (SPEs) and as binders, coatings and interlayers to address issues in solid-state batteries with inorganic solid electrolytes (ISEs). We also consider the value of tunable polymer flexibility, added capacity, skin compatibility and end-of-use degradability of polymeric materials in wearable technologies such as smartwatches and health monitoring devices. While many years have been spent on SPE development for batteries, delivering competitive performances to liquid and ISEs requires a deeper understanding of the fundamentals of ion transport in solid polymers. Advanced polymer design, including controlled (de)polymerisation strategies, precision dynamic chemistry and digital learning tools, might help identify these missing fundamental gaps towards faster, more selective ion transport. Regardless of the intended use as an electrolyte, composite electrode binder or bulk component in flexible electrodes, many parallels can be drawn between the various intrinsic polymer properties. These include mechanical performances, namely elasticity and flexibility; electrochemical stability, particularly against higher-voltage electrode materials; durable adhesive/cohesive properties; ionic and/or electronic conductivity; and ultimately, processability and fabrication into the battery. With this, we assess the latest developments, providing our views on the prospects of polymers in batteries and wearables, the challenges they might address, and emerging polymer chemistries that are still relatively under-utilised in this area.

Algorithm for Preliminary Analysis of Diffraction Patterns of Nanocomposite Materials with an Admixture of a Bulk Component

Algorithm for Preliminary Analysis of Diffraction Patterns of Nanocomposite Materials with an Admixture of a Bulk Component

Toughening brittle kraft lignin coating on mismatched substrate with spider Silk-Inspired protein as an interfacial modulator

Current production of functional coatings majorly relies on petrochemical formulations. While they have provided substantial benefits, their fabrication processes as well as their disposal created widespread ecological catastrophes. Thus, there is a pressing demand and calls for a radical transformation to develop sustainable solutions by using renewable building blocks. Herein, we report on a novel coating formulation by combining largely undervalued kraft lignin from the forest industry, with genetically engineered and recombinantly produced spider silk-inspired protein through the industrial biotechnology platform. Unmodified kraft lignin was used as the main bulk component in the coating given its abundance and low cost. The nanometer-thin spider silk-inspired protein (SSIP) was used as a primary layer exhibiting dual functionalities: (i) modulating the mechanical properties of inherently brittle kraft lignin, (ii) substantially increasing the interfacial binding of kraft lignin to the underlying rigid silica substrate with the mismatched physicochemical properties. Our findings demonstrate how synergistic interplay components could result in scalable and durable functional coatings which could potentially be used in various medical and industrial applications in the future.

Levitation force approximation of YBCO hybrid superconductors using critical-state theory and partitioning method

Introducing the second-generation coated conductor tapes (2G tapes) can enhance the performance of yttrium-barium-copper-oxide bulk superconductors (SCs) in terms of force, damping, and shape diversity. In this study, we investigate a hybrid SC that utilizes 2G tapes wrapped around the pivotal bulk component to achieve performance improvements. We also present a straightforward method, based on critical-state theory, to approximate the levitation force of this hybrid SC. This method characterizes the stack of tapes as an equivalent bulk with higher anisotropy and applies a fitting Kim model as an integrated expression of J (H) and J anisotropy. The partitioning method divides the SC into several isolated elements where the external field is approximately uniform within each sub-volume. Comparisons of calculated results with experiments indicate that this method can predict levitation properties with reasonable accuracy in just a few seconds. Furthermore, we propose two geometries of hybrid SC, namely, width-hybrid, and height-hybrid SC, for practical applications. Among them, the width-hybrid form exhibits higher efficiency in levitation. Our findings highlight the importance of applying the coated conductor stack when the magnetic field orientation is perpendicular to the a–b planes.

Forensic Discrimination of Smokeless Powders Using Carbon and Nitrogen Isotope Ratios.

Improvised explosive devices pose a threat to the public by way of terrorism and criminal activities. In the United States a commonly used low explosive in improvised explosive devices is smokeless powder (SP), due to its ease of access. Traditionally, forensic examinations are often sufficient in determining the physical and chemical characteristics of SPs. However, these exams are limited in differentiating or associating SPs when comparing two materials which are physically and/or chemically consistent. Stable isotope analysis of carbon and nitrogen has been used for explosives to further forensic chemical comparisons and aid in sample differentiation. In this manuscript we explore the utility of stable isotope analysis of SPs to differentiate manufacturer and geographic origin. Both bulk isotope analysis and component isotope analysis of carbon and nitrogen via an extraction method using dichloromethane were evaluated to compare the overall isotope signature of individual SPs. Through the combination of bulk and component isotope measurements of SPs, we were able to identify geographic relationships; however, the manufacturer origins were not as clearly discriminated. This technique demonstrates a potential improvement to traditional forensic examinations of smokeless powder by adding additional information when explosives are chemically and/or physically consistent.

The ST component in the Si 2p photoemission spectrum from H-terminated and oxidized Si (001) surfaces

One doublet is usually employed to fit the Si0 substrate species in the Si 2p photoemission spectra from Si (001) H-terminated (after piranha treatment) and oxidized surfaces. However, there is a second substrate-top component (ST) with a binding energy of 0.3 eV higher than the bulk component; its intensity varies from ∼10% at normal emission (i.e., 90° from the surface) to ∼20% at 35°. It is present even for oxidized surfaces and does not correspond to any of the suboxide species. It corresponds to the first layers of the substrate and is responsible for the decrease in the signal dip between the two S–O branches of the Si 2p spectra for glancing electron takeoff angles. Although it is resolvable for monochromatized sources, the ST component is absent in the literature on Si 2p spectra.

Multipole expansion of the local expansion rate

We design a new observable, the expansion rate fluctuation $\ensuremath{\eta}$, to characterize deviations from the linear relation between redshift and distance in the local universe. We also show how to compress the resulting signal into spherical harmonic coefficients in order to better decipher the structure and symmetries of the anisotropies in the local expansion rate. We apply this analysis scheme to several public catalogs of redshift-independent distances, the Cosmicflows-3 and Pantheon datasets, covering the redshift range $0.01<z<0.05$. The leading anisotropic signal is stored in the dipole. Within the standard cosmological model, it is interpreted as a bulk motion ($307\ifmmode\pm\else\textpm\fi{}23\text{ }\text{ }\mathrm{km}/\mathrm{s}$) of the entire local volume in a direction aligned at better than 4 degrees with the bulk component of the Local Group (LG) velocity with respect to the cosmic microwave background (CMB). This term alone, however, provides an overly simplistic and inaccurate description of the angular anisotropies of the expansion rate. We find that the quadrupole contribution is non-negligible ($\ensuremath{\sim}50%$ of the anisotropic signal), in fact, statistically significant, and signaling a substantial shearing of gravity in the volume covered by the data. In addition, the 3D structure of the quadrupole is axisymmetric, with the expansion axis aligned along the axis of the dipole. Implications for the determination of the ${H}_{0}$ parameter are discussed. We find that Hubble constant estimates may show variation as high as $\mathrm{\ensuremath{\Delta}}{H}_{0}=(4.1\ifmmode\pm\else\textpm\fi{}1.1)\text{ }\text{ }\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$ between antipodal directions along the dipole axis. In the case of the Pantheon sample, this systematic difference is reduced to $\mathrm{\ensuremath{\Delta}}{H}_{0}=(2.4\ifmmode\pm\else\textpm\fi{}1.1)\text{ }\text{ }\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$ once model-dependent correction for peculiar velocity flows are implemented. Notwithstanding, the axial anisotropy in the general direction of the CMB dipole is still detected. We thus show how to optimally subtract redshift anisotropies from Pantheon data in a fully model-independent way by exploiting the $\ensuremath{\eta}$ observable. As a result, the value of the best fitting ${H}_{0}$ is systematically revised upwards by nearly $0.7\text{ }\text{ }\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$ (about $2\ensuremath{\sigma}$) compared to the value deduced from the Hubble diagram using the uncorrected observed redshift. The goodness of fit is also improved.

A deposition strategy for Wire Arc Additive Manufacturing based on temperature variance analysis to minimize overflow and distortion

Wire Arc Additive Manufacturing method allows producing relatively large metal parts with minimum raw material. However, the high heat input used during production results in heat accumulation and temperature variance. Both of them can cause various problems, such as distortion, overflow, and residual stress. Heat accumulation is the rise in temperature that occurs as a result of the inability to remove heat from the part. On the other hand, temperature variance arises as a result of the deposition path planning, which is usually carried out according to the geometrical shape of the part section. In traditional deposition path planning approaches, temperature variance is not taken into account for two reasons: high computational cost and the need to use more than one tool to implement path planning and thermal analysis. In this study, an algorithm that plans deposition paths by one step via performing thermal analysis to minimize temperature variance on a path basis is presented. The algorithm determines the deposition path by finding the best deposition angle and the sequence of tracks according to the jumping to the coldest deposition area. Thus, the temperature variance is reduced significantly. To evaluate the algorithm performance, a part consisting of a bulk component and a thin-walled component was produced in the workshop using the proposed algorithm and traditional sequential raster strategy. The results showed that the developed strategy reduced surface deformation by 37 % and thin-walled overflow by 21 %.

Numerical investigations of the bulk-surface wave pinning model

The bulk-surface wave pinning model is a reaction–diffusion system for studying cell polarisation. It is constituted by a surface reaction–diffusion equation, coupled to a bulk diffusion equation with a non-linear boundary condition. Cell polarisation arises as the surface component develops specific patterns. Since proteins diffuse much faster in the cell interior than on the membrane, in the literature, the bulk component is often assumed to be spatially homogeneous. Therefore, the model can be reduced to a single surface equation. However, in real applications a spatially non-uniform bulk component might be an important player to take into account. In this paper, we study, through numerical computations, the role of the bulk component and, more specifically, how different bulk diffusion rates might affect the polarisation response. We find that the bulk component is indeed a key factor in determining the surface polarisation response. Moreover, for certain geometries, it is the spatial heterogeneity of the bulk component that triggers the polarisation response, which might not be possible in a reduced model. Understanding how polarisation depends on bulk diffusivity might be crucial when studying models of migrating cells, which are naturally subject to domain deformation.

High oxidation state enabled by plated Ni-P achieves superior electrocatalytic performance for 5-hydroxymethylfurfural oxidation reaction

SummaryElectrochemical 5-hydroxymethylfurfural oxidation reaction (HMFOR), as a clean biorefinery process, promotes a circular economy with value-added products. In HMFOR, the intrinsic catalytic activity and charge transfer mechanisms are crucial. Herein, nickel, co-deposited with phosphorus (Ni-P), attains superior electrocatalytic performance compared with Ni and its oxyhydroxides for the HMFOR. Such electrocatalytic activity of the Ni-P catalyst is attributed to the high oxidation state of surface Ni species, supported by the bulk Ni-P component. An unprecedented charge storing capacity enabled by the bulk Ni-P material maintains the spontaneous reaction between HMF and Ni3+ species to achieve a current density of 10 mA/cm2 normalized by the electrochemical active surface area at a low potential of 1.42 V vs RHE, reaching a 97% Faradaic efficiency toward 2,5-furandicarboxylic acid. This work, for the first time, sheds light on the importance of the electrode bulk material by showcasing the HMFOR via the Ni-P catalyst incorporating a charge-holding bulk component.

Advanced forced degradation technique for simultaneous estimation of azelnidipine and telmisartan implementing AQbD approach in its tablet dosage form

For simultaneous estimation of Azelnidipine and Telmisartan in pharmaceutical dosage form, a simple, rapid, precise and reproducible RP-HPLC method was developed. Separation was achieved on a Phenomanax Luna C18; 5 μm, 150 mm × 4.6 mm i.d. column using water and methanol 50: 50 (v/v) as mobile phase and detected at 256 nm using PDA detector. Azelnidipine and Telmisartan were exposed to thermal, photolytic, hydrolytic and oxidative stress conditions and stressed samples were analyzed by the proposed method. Linearity, precision, accuracy, specificity and robustness were studied as reported in the International Council for Harmonization guidelines. Linearity of the proposed method was in the range of 4-12 μg mL-1 (r2 = 0.998) for Azelnidipine and 20-60 μg mL-1 (r2 = 0.997) for Telmisartan. Limits of Detection were 1.041 μg mL-1 and 0.208 μg mL-1, while Limits of Quantitation were 3.155 μg mL-1 and 0.631 μg mL-1 for Azelnidipine and Telmisartan respectively. Degradation products produced as a result of stress studies did not interfere with the detection. The proposed stability studies method for simultaneous estimation was found to be specific, accurate and economical that could be applied for routine analysis of drugs in bulk and multi component formulations in quality control laboratories.

Submicrometer spectromicroscopy of UO2 aged under high humidity conditions

The oxidation of uranium dioxide is a complicated process, depending on factors including humidity, temperature, and microstructure. To further determine the characteristics of this process, UO2 particles were allowed to age and agglomerate under 98% relative humidity at room temperature for 378 days. A focused ion beam (FIB) section of this agglomeration was then measured at the O K-edge, U N5-edge, and C K-edge using the scanning transmission x-ray microscope (STXM) at the Advanced Light Source. O K-edge and U N5-edge x-ray absorption measurements allowed for the elemental and chemical species mapping of the agglomerates and indicated the formation of schoepite at the submicrometer scale in specific locations. Non-negative matrix factorization was employed to elucidate the main components at the O K-edge, which were uranyl (schoepite) formed primarily at the interface of the sample with controlled atmosphere, a UO2-like bulk component present in the majority of the sample, and an oxygen species present at the surface of the FIB section, which is likely adsorbed water. STXM spectromicroscopy measurements at the U N5-edge measurements also confirmed the location of oxidized uranium. This analysis is a valuable insight into the formation of schoepite on UO2 and shows the sensitivity to and utility of STXM spectromicroscopy for uranium speciation.

Amphibian mucus triggers a developmental transition in the frog-killing chytrid fungus

The frog-killing chytrid fungus Batrachochytrium dendrobatidis (Bd) is decimating amphibian populations around the world.1-4Bd has a biphasic life cycle, alternating between motile zoospores that disperse within aquatic environments and sessile sporangia that grow within the mucus-coated skin of amphibians.5,6 Zoospores lack cell walls and swim rapidly through aquatic environments using a posterior flagellum and crawl across solid surfaces using actin structures similar to those of human cells.7,8Bd transitions from this motile dispersal form to its reproductive form by absorbing its flagellum, rearranging its actin cytoskeleton, and rapidly building a chitin-based cell wall-a process called "encystation."5-7 The resulting sporangium increases in volume by two or three orders of magnitude while undergoing rounds of mitosis without cytokinesis to form a large ceonocyte. The sporangium then cellurizes by dividing its cytoplasm into dozens of new zoospores. After exiting the sporangium through a discharge tube onto the amphibian skin, daughter zoospores can then reinfect the same individual or find a new host.5 Although encystation is critical to Bd growth, whether and how this developmental transition is triggered by external signals was previously unknown. We discovered that exposure to amphibian mucus triggers rapid and reproducible encystation within minutes. This response can be recapitulated with purified mucin, the bulk component of mucus, but not by similarly viscous methylcellulose or simple sugars. Mucin-induced encystation does not require gene expression but does require surface adhesion, calcium signaling, and modulation of the actin cytoskeleton. Mucus-induced encystation may represent a key mechanism for synchronizing Bd development with the arrival at the host.

Determination of Critical Temperature of Scuffing for AISI 8620 Steel Gear Contacts Lubricated by Dexron 6 Through Computational Simulation of Experiment

Abstract This study establishes the critical temperature of scuffing for contacts of gears made of AISI 8620 steel alloy, lubricated by Dexron 6 oil. Through thermal mixed elastohydrodynamic lubrication modeling, experimental scuffing failures are simulated to determine the associated maximum surface temperature, which consists of bulk and flash components. This temperature is referred as the limiting/critical temperature of scuffing and is believed to be independent of operating conditions, while vary for different solid material and lubricant pairs. It is found that sump lubricant temperature rise affects surface temperature by contributing to the bulk component. The flash component is largely dictated by asperity interactions within the contact zone, where Hertzian pressure is not an appropriate measure of micro-scale asperity contact loading. The observed scuffing scars are shown to be in good agreement with the high temperature zone predicted by the computational model.

On-Site Analyses as a Decision Support Tool for Dredging and Sustainable Sediment Management

Beneficial use of dredged sediments, either in harbours or waterways, is based on their potential as alternative resources. Such sediments can be considered as bulk materials for industrial needs, which is predicated on their current waste status or meeting end-of-waste constraints. They also can be an integral part of beneficial use projects using sediments as a bulk component, including civil engineering and landscaping. This is particularly important for beneficial use projects focusing on climate change effects mitigation, such as flood protection works, coastline defence or littoral urban areas redevelopment. When dredged sediment is used as a bulk material, its acceptability is based on an assumed homogeneity of its properties. On-site analyses allow pre-dredging detailed mapping at a denser scale than laboratory ones; monitoring dredgings during operations and during processing; and continuous control of their properties at the implementation site. This is currently possible only for a selection of inorganic analytes. When dredgings are part of a larger beneficial use project, on-site analyses facilitate first the baseline survey and the sediment source characterisation. Continuous monitoring of the sediment load allows a fast detection of contamination hot spots and their adequate management. Site survey via on-site instruments allow end users and communities to check themselves the contamination level, hence acceptability is better. On-site dredged sediment analyses monitor both building properties and environmental compliance; soil and sediment analyses at receiving sites; surface and groundwater, either for impact assessment or for monitoring works. On-site instruments provide immediate results and allow dynamic or adaptive sampling strategies, as well as allowing operational decisions in real time. Confirmation by laboratory analyses is required for validation, but on-site sample screening for laboratory analyses improves their efficiency. The present paper was developed on the basis of an earlier presentation, which it developed and updated extensively.

Определение вклада массивной компоненты из анализа искажений формы линии дифракционных спектров для нанокомпозитных материалов

Using the analysis of the elastic lines distortions of the diffraction spectra with the involvement of the high order central moments of the distribution, the sensitivity of the developed technique to the presence of an admixture of a bulk component in nanocomposite materials was estimated. Cases for the main types of instrumental resolution functions of diffractometers and functions describing the response from materials embedded in the pore space of nanomatrices such as SBA-15, MCM-41, MCM-48, etc. are considered.