Dense Metal Research Articles

Study of magnetic field error suppression methods based on atomic parameters of cell in atomic co-magnetometer rotation measurement

Abstract We propose a new model for magnetic field errors based on the rotation measurement of the K-Rb-$^{21}{\rm{Ne}}$ co-magnetometer, considering the density ratio and spin collisions. The spin polarization characteristics of different alkali metal density ratios were analyzed by creating five cells with different density ratios, and the correctness of the magnetic field error model was verified experimentally. Moreover, the effects of five different alkali metal density ratios of cells on the sensitivity, long-term stability and magnetic field error suppression of the K-Rb-$^{21}{\rm{Ne}}$ co-magnetometer were investigated experimentally. When the density ratio is 1:107, there can be the optimal magnetic field error suppression effect, sensitivity and long-term stability. According to the derived magnetic field error equation, the magnetic noise error of the K-Rb-$^{21}{\rm{Ne}}$ co-magnetometer with an optimized density ratio is reduced by nearly 5 times from 260$^{\circ}$/h/nT to 56.5$^{\circ}$/h/nT, the sensitivity is improved from 2.9$\times$10$^{-5}$ $^{\circ}$/s/Hz$^{1/2}$ to 7.0$\times$10$^{-6}$ $^{\circ}$/s/Hz$^{1/2}$ at 1 Hz, and the long-term stability Allan variance over two hours is improved from 1.9$\times$10$^{-2}$ $^{\circ}$/h to 8.9$\times$10$^{-3}$ $^{\circ}$/h. This result provides a theoretical basis for designing the parameters of the K-Rb-$^{21}{\rm{Ne}}$ co-magnetometer cell.

THE IMPACT OF PHOSPHORUS WEAPONS DURING A FULL-SCALE WAR

Due to military actions, there is destruction of Ukraine's ecosystems, deterioration of sanitary and hygienic indicators of drinking water, air, and soil. With the onset of full-scale war, the negative impact of harmful and dangerous substances (the use of chemical, phosphorus bombs, and other weapons) prohibited by the Geneva Convention leads to unforeseen consequences for the environment of Ukraine. The purpose of the study is to analyze injuries resulting from the action of white phosphorus of various types of phosphorus weapons, namely explosive weapons with a wide area of effect, mines, ammunition, long-range missiles; artillery, mortar shells, various types of grenades in the conditions of russian aggression against Ukraine. The following methods were used in the work: content analysis, comparative analysis, and systematization of the researched material. Research of scientific publications by domestic and foreign scientists using the PubMed and Google Scholar databases for the period 2001-2023 was conducted. Phosphorus munitions such as WP are known for their high effectiveness in combat operations, but also lead to serious injuries, both traumatic and post-traumatic psychological changes. White phosphorus (explosive bombs) causes burns of human body tissues upon contact with burning material, as well as burns of the upper respiratory tract due to inhalation of smoke or gases emitted during combustion. The article analyzes the regulatory framework prohibiting the use of phosphorus munitions in armed conflicts. Clinical cases of gunshot combined injuries of limbs with massive soft tissue defects, gunshot fractures, and the presence of multiple foreign bodies of metal density due to the use of phosphorus munitions are considered. An analysis of scientific research by foreign scientists on this issue was conducted. The article provides algorithms for providing first aid due to the action of phosphorus munitions, as well as methodological recommendations of the Ministry of Health of Ukraine (Order of the Ministry of Health of Ukraine No. 506 of March 20, 2022) for providing medical assistance at the prehospital stage in case of phosphorus munition injuries, burns, enteral poisoning, exposure to white phosphorus in the eyes.

Resistive Heating and Thermal Decomposition of an Additively Manufacturable Electrically Conductive Explosive

AbstractThe ability to transmit electrical signals through high explosive charges without using dense metal conductors could enable continuous monitoring of explosive charges with internally embedded sensors. With the sensor materials themselves being energetic, the impact on the intended detonation performance of the charge can be minimized. Embedded sensors enable real time, in‐situ measurements of conditions relevant to ageing assessments. Additionally, dynamic material property sensing can provide detonation performance data, enabling measurement of dynamic shock position. One proposed method to allow for electronic signal transfer through high explosives is to use electrically conductive explosive composites consisting of an electrically conductive polymer binder mixed with high explosive crystals. These conductive energetic pathways also serve as independently reactive elements and can provide additional functionality via dynamic sensor removal through resistive heating and subsequent decomposition. This work discusses the resistive heating of a previously developed, poly (3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) based, electrically conductive extrudable explosive composite. Experimental samples of the conductive explosive material were subjected to a range of direct current applications and the resulting heating and decomposition of the material is discussed.

Origin of the distinct site occupations of H atom in hcp Ti and Zr/Hf

The location of the H atoms in Ti, Zr, and Hf is crucial to the formation of the hydrides in these metals as it influences the crystal lattice transformation and the hydrogen diffusion involved in the hydride formation process. Although Ti, Zr, and Hf are all of hexagonal close-packed structure with similar lattice parameters, the solute H atom occupies the octahedral interstice in Ti but the tetragonal interstice in Zr and Hf, of which the origin is still mysterious. In the present work, the origin of the distinct site occupation behavior of H atom in Ti and Zr/Hf is investigated through first principles calculations. The calculated solution energies confirm that H prefers the octahedral interstice in Ti but the tetrahedral interstice in Zr and Hf. We ascribe the distinct site occupations of H in Ti and Zr/Hf to the varying Coulomb repulsion between the H (as a screened proton in the metals) and the matrix atoms against the interstitial size. The competition between the H-induced electron accumulation effect and the matrix atom debonding effect might matter as well. We propose that, as a general rule, a H atom prefers the site with a trade-off between a large space and a high electron density in metals.

A non-thermal method to maintain alkali vapor density of anti-relaxation coating cell in spin exchange relaxation-free magnetometer

The long-term stability of alkali metal vapor cell density is crucial for the performance of Spin Exchange Relaxation-Free (SERF) magnetometers. This paper addresses the issue of atomic density consistency commonly encountered with OTS and paraffin coatings in current quantum magnetometers. For the first time, the LIAD non-thermal method is applied to SERF magnetometers to maintain the long-term stability of alkali metal density. The study identifies the critical roles of desorption light luminous flux and integrating sphere uniformity in enhancing LIAD effectiveness. A new model based on the absorption spectrum of 85Rb and 87Rb was developed, achieving an R-square value of 0.989 and revealing a rubidium isotopic abundance ratio of 2.8:1, with OTS-coated cells showing the highest density retention. These findings contribute to the advancement of cryogenic SERF magnetometers by providing a deeper understanding of LIAD mechanisms and offering a viable alternative to thermal density control methods.

Optical transmission, dielectric constants, and gamma shielding performance of Se95-xIn5Prx metallic alloys: Radiation protection applications

Due to the high density of metals, metallic materials such as alloys have the potential to have high gamma-radiation-absorbing abilities. This would make them relevant in a radiation environment as either a shielding material or a radiation sensor. These would, however, depend on their gamma radiation responses. Research aimed at evaluating the gamma response parameters of different glassy alloys that have technical applications is scarce compared to the traditional characterization with respect to optical features, structural evolution, and mechanical strength. In this paper, the optical and radiation shielding abilities of Se95-xIn5Prx (x = 2, 4, and 6) glassy alloys were investigated using standard theoretical techniques. The mass attenuation coefficient (MAC) of the materials was computed using the XCOM software. Reflection loss values are 0.20218, 0.22634, and 0.22908 for SIPr1, SIPr2, and SIPr3, respectively, while the optical transmittance values are 0.66365, 0.63087, and 0.62723 in the same order. The metallization criterion declined when Pr increased in the alloy. The values of MAC ranged from 0.0317 cm2/g to 98.2099 cm2/g for SIPr1, 0.0319 cm2/g to 97.3798 cm2/g for SIPr2 and 0.0322 cm2/g to 96.5372 cm2/g for SIPr3. The Higher attenuation and absorption coefficients were found for Pr-rich alloys. Pr therefore increase the ability of the SIPr-alloy to attenuate and absorb photon energy. The optical parameters of the investigated alloys could be used to identify their optical applications. SIPr3 had comparatively higher shielding ability compared to some known shields and could thus be used for radiation control and protection purposes.

Sintering densification mechanism of binder jet 3D printing 316L stainless steel parts via dimensional compensation technology

The dimensional compensation technology can achieve high dense metal parts with precise dimensions for binder jet 3D printing (BJ3DP). In this study, two models (cuboid and gear) of BJ3DP 316L stainless steel (BJ3DP316LSS) parts were established. Numerical simulation and experimental volume shrinkage of the BJ3DP316LSS sintered parts via dimensional compensations technology were investigated. When the dimensional compensation coefficient was set as 1.25, the BJ3DP316LSS cuboids and gears exhibited high densification as 99.6% and 99.4%, respectively. The experimental dimension deviation rates of cuboid and gear parts after dimensional compensations ranged from −3.56% to −0.15% and from 0.89% to 3.42%, respectively. Due to twinning-induced plasticity mechanism, the BJ3DP316LSS sintered gear part via dimensional compensation technology exhibited high hardness (∼139 HV), high yield strength (∼249 MPa), high ultimate tensile strength (∼546 MPa) and excellent elongation (∼62%), which are higher than those of the reported 316LSS samples.

Study on the effect of Lorentz force on the nuclear reactor core melt stratification in electromagnetic cold crucible

To understand the effect of the Lorentz force on core melt stratification during experiments, a multi-physical field coupling model of electromagnetic induction, non-isothermal flow, and two-phase flow is established in this paper. The evolution of the layered core melt in the electromagnetic cold crucible is studied for different relative densities and phase volume fraction ratios between metal and oxide. The calculation results show that the coupling model can accurately describe the structural evolution of core melt. The Lorentz force cannot change the relative positions of the metal and oxide, but it can significantly affect the morphology of the core melt. If the density of the metal is less than that of the oxide, the Lorentz force causes the light metal with a small phase volume fraction to form a hemispherical shape in the top center of the crucible. As the phase volume fraction increases, the Lorentz force become weaker than those of gravity and buoyancy. The light metal is then flat. When the metal density is greater than the oxide density, the Lorentz force causes the heavy metal with a small phase volume fraction to appear as a hemisphere, but causes the heavy metal with a large phase volume fraction to appear as an ellipsoid in the lower part of the crucible.

Hydrogen Separation Membranes: A Material Perspective

The global energy market is shifting toward renewable, sustainable, and low-carbon hydrogen energy due to global environmental issues, such as rising carbon dioxide emissions, climate change, and global warming. Currently, a majority of hydrogen demands are achieved by steam methane reforming and other conventional processes, which, again, are very carbon-intensive methods, and the hydrogen produced by them needs to be purified prior to their application. Hence, researchers are continuously endeavoring to develop sustainable and efficient methods for hydrogen generation and purification. Membrane-based gas-separation technologies were proven to be more efficient than conventional technologies. This review explores the transition from conventional separation techniques, such as pressure swing adsorption and cryogenic distillation, to advanced membrane-based technologies with high selectivity and efficiency for hydrogen purification. Major emphasis is placed on various membrane materials and their corresponding membrane performance. First, we discuss various metal membranes, including dense, alloyed, and amorphous metal membranes, which exhibit high hydrogen solubility and selectivity. Further, various inorganic membranes, such as zeolites, silica, and CMSMs, are also discussed. Major emphasis is placed on the development of polymeric materials and membranes for the selective separation of hydrogen from CH4, CO2, and N2. In addition, cutting-edge mixed-matrix membranes are also delineated, which involve the incorporation of inorganic fillers to improve performance. This review provides a comprehensive overview of advancements in gas-separation membranes and membrane materials in terms of hydrogen selectivity, permeability, and durability in practical applications. By analyzing various conventional and advanced technologies, this review provides a comprehensive material perspective on hydrogen separation membranes, thereby endorsing hydrogen energy for a sustainable future.

Heavy metal in radiation therapy: A simple method to differentiate hip prosthesis materials.

In recent years, the number of hip replacement patients receiving radiation therapy has steadily increased. In parallel, strategies have been developed to reduce metal artifacts in computed tomography (CT) images and improve the accuracy of dose calculation algorithms. However, in certain situations, knowledge of the type of prosthesis material is required to accurately determine the dose distribution. This study aims to identify physical materials in hip prostheses to correctly assign them in the treatment planning system and improve dose calculation accuracy. We first verified the validity of the extended CT mass density calibration curve measured on titanium (Ti) and stainless steel (SS) metal inserts of two different diameters. Then using dedicated reference objects of various circular diameters, we developed a method based on interpolation functions to differentiate between Ti and SS material groups. Forty data sets from 18 patients were used to validate our method on two different reconstruction kernels: a standard Br44f and the electron DirectDensity (Sd40f) kernels from Siemens. Hounsfield units (HU) of Ti and SS inserts were found to vary widely depending on insert diameter, CT spectrum, and reconstruction kernels due to cupping artifacts. The largest HU difference (-79%) was obtained for SS at 70kV with Br44f when the diameter increased from 8 to 30mm. Therefore, under these conditions, the extended CT-density calibration curve is not recommended for heavy metal density determination. Using our interpolation-based method, we achieved excellent detection (100%) and material differentiation (100%) results for stems in both reconstruction kernels. At CT energies between 110 and 140kV, the detection and material differentiation rates were 93.3% and 92.9% for the heads and 93.3% and 92.9% for the acetabular cups, respectively, with the Br44f. Similarly, the use of Sd40f resulted in detection and differentiation rates of 94.7% and 100% for the heads and 100% and 95.0% for the acetabular cups, respectively. This method makes it possible to differentiate between hip prosthesis materials and correctly assign them to the Ti or SS group without prior knowledge of the prosthesis type, regardless of the reconstruction kernels. In combination with the Acuros XB (Varian) or Monte Carlo dose algorithms, excellent dosimetric accuracy can be achieved even in the vicinity of hip prostheses. By performing basic measurements, the method can be adapted to other CT units and reconstruction kernels, replacing the use of an extended CT-density calibration curve.

Effects of accelerated carbonation on fine incineration bottom ash: CO2 uptake, strength improvement, densification, and heavy metal immobilization

Incinerating municipal solid waste (MSW) can effectively reduce its mass and volume while producing electricity. However, this process generates incineration bottom ash (IBA), which is an aggregate-like waste containing heavy metals. Due to the higher heavy metal contents, fine IBA can be removed from total IBA and treated separately to promote the use of IBA. Furthermore, MSW incineration generates carbon dioxide (CO2), which is another concern. In this context, it is beneficial to use accelerated carbonation to treat fine IBA, because it can not only contribute to carbon capture but also provide carbonated IBA that may be utilized as aggregates in civil engineering. The accelerated carbonation process of fine IBA is affected by many parameters. Therefore, this study investigated the effects of CO2 pressure (PCO2), initial water content (wi), and carbonation time on the properties of carbonated IBA, including CO2 uptake, unconfined compressive strength (UCS), density, and leaching of heavy metals. The evolution of mineralogy and microstructure of carbonated IBA was also analyzed. The results showed that IBA with wi of 15% and PCO2 of 200 kPa could achieve a CO2 uptake of 6% of IBA mass. The carbonation time significantly affected UCS and dry density of carbonated IBA. As the carbonation time increased from 0 h to 120 h, the UCS increased from 67 kPa to 691 kPa while the dry density increased from 1.38 g/cm3 to 1.51 g/cm3. Compared with untreated IBA, the leaching concentrations of Cu, Cr, Zn, and Pb from carbonated IBA were reduced significantly. As the carbonation time increased, the microstructure of carbonated IBA became denser. This densified structure was one of the reasons for the strength improvement and dry density increment of carbonated IBA.

In Vivo Assessment of a Triple Periodic Minimal Surface Based Biomimmetic Gyroid as an Implant Material in a Rabbit Tibia Model.

Biomimetic approaches to implant construction are a rising frontier in implantology. Triple Periodic Minimal Surface (TPMS)-based additively manufactured gyroid structures offer a mean curvature of zero, rendering this structure an ideal porous architecture. Previous studies have demonstrated the ability of these structures to effectively mimic the mechanical cues required for optimal implant construction. The porous nature of gyroid materials enhances bone ingrowth, thereby improving implant stability within the body. This enhancement is attributed to the increased surface area of the gyroid structure, which is approximately 185% higher than that of a dense material of the same form factor. This larger surface area allows for enhanced cellular attachment and nutrient circulation facilitated by the porous channels. This study aims to evaluate the biological performance of a gyroid-based Ti6Al-4V implant material compared to a dense alloy counterpart. Cellular viability was assessed using the lactate dehydrogenase (LDH) assay, which demonstrated that the gyroid surface allowed marginally higher viability than dense material. The in vivo integration was studied over 6 weeks using a rabbit tibia model and characterized using X-ray, micro-CT, and histopathological examination. With a metal volume of 8.1%, the gyroid exhibited a bone volume/total volume (BV/TV) ratio of 9.6%, which is 11-fold higher than that of dense metal (0.8%). Histological assessments revealed neovascularization, in-bone growth, and the presence of a Haversian system in the gyroid structure, hinting at superior osteointegration.

Development of Flexible and Partly Water-Soluble Binder Systems for Metal Fused Filament Fabrication (MF3) of Ti-6Al-4V Parts.

Metal Fused Filament Fabrication provides a simple and cost-efficient way to produce dense metal parts with a homogenous microstructure. However, current limitations include the use of hazardous and expensive organic solvents during debinding for flexible filaments the stiffness of filaments made from partly water-soluble binder systems. In this study, the influence of various additives on different partly water-soluble binder systems, with regard to the flexibility and properties of the final parts, was investigated. Furthermore, a method using dynamic mechanical analysis to quantify the flexibility of filaments was introduced and successfully applied. For the first time, it was possible to produce flexible, partly water-soluble filaments with 60 vol.% solid content, which allowed the 3D printing of complex small and large parts with a high level of detail. After sintering, density values of up to 98.9% of theoretical density were achieved, which is significantly higher than those obtained with existing binder systems.

Numerical Analysis of the Aluminium Alloy Structure of the Brackets based on Conceptualization Processes

In this study, three conceptual designs of bracket constructions made of aluminum alloy underwent numerical investigation. To analyze the von Mises stresses present throughout the entire structure, the Ansys program was employed in conjunction with the static structure tool. The selection criteria are determined by two primary elements. The first element is the performance of the design, represented by normal stresses and deformation resulting from the applied load. The second criterion is volume, dependent on the volume itself, represented by a certain density of metals. To select an appropriate design for the aluminum brackets, the procedure was carried out utilizing the Analytic Network Process (ANP) technique. Through the conceptualizing approach, it has been demonstrated that the second design is superior to the alternative.

Electron impact ionization in dense plasmas

The distorted-wave with exchange (DWE) method is employed to evaluate electron impact ionization cross sections in dense electron–ion plasmas. Bound and continuum electron wave functions are obtained from a non-relativistic average-atom code. Plots of DWE cross sections are presented for 1s electrons in Li and Be plasmas and 2p electrons in Na and Mg plasmas. For each of these elements, cross sections are evaluated at metallic density in a range of temperatures from 10 to 100 eV and at their respective melting points. Resonances in the cross sections appear near the incident energy threshold at high temperatures. The origin of these resonances is discussed. In general, the distorted wave (DW) method without exchange is found to be a good approximation to the DWE method for electron impact ionization calculations. In the resonance region, however, exchange effects are found to be very important and cannot be neglected.

Cemented in place: kyphoplasty-associated pulmonary cement embolism: a case report

BackgroundKyphoplasty-associated cement extravasation into surrounding tissue and vasculature can lead to life-threatening complications. We present a rare case of significant inferior vena cava cement burden that resulted in pulmonary embolism.Case presentationA 74-year-old Caucasian woman with a history of severe osteoporosis, recurrent falls, and spinal compression fracture status post-kyphoplasty of the L4–L5 vertebrae, presents to the emergency department 2 days post-vertebral kyphoplasty due to chest pain, back pain, and dyspnea. Computed tomography of the chest and abdomen showed a metallic density within the inferior vena cava extending superiorly approximately 10 cm from the vertebral L5 level. She was also found to have right lower lobe pneumonia. The patient finished a 10-day course of antibiotics and was discharged home with a 1-month long course of anticoagulation with apixaban per recommendations of a multidisciplinary team consisting of Hematology/Oncology, Interventional Radiology, Vascular Surgery, and Orthopedic Surgery. Unfortunately, the patient was readmitted a month later with shortness of breath. Work up was notable for an influenza type A infection and computed tomography findings of pulmonary cement embolism. The respiratory distress was resolved with supportive care. Despite pulmonary cement burden, the multidisciplinary care team recommended no further anticoagulation. Patient was discharged home with close clinical follow-up and 6 months has since passed at the time of this report without reported complications.ConclusionsA large cement burden in the inferior vena cava leading to pulmonary cement embolism is a rare event. A high burden of cement predisposes development of pulmonary embolism. A short course of anticoagulation may only be needed for asymptomatic patients.

Surface Doping and Dual Nature of the Band Gap in Excitonic Insulator Ta2NiSe5.

Excitons in semiconductors and molecules are widely utilized in photovoltaics and optoelectronics, and high-temperature coherent quantum states of excitons can be realized in artificial electron-hole bilayers and an exotic material of an excitonic insulator (EI). Here, we investigate the band gap evolution of a putative high-temperature EI Ta2NiSe5 upon surface doing by alkali adsorbates with angle-resolved photoemission and density functional theory (DFT) calculations. The conduction band of Ta2NiSe5 is filled by the charge transfer from alkali adsorbates, and the band gap decreases drastically upon the increase of metallic electron density. Our DFT calculation, however, reveals that there exist both structural and excitonic contributions to the band gap tuned. While electron doping reduces the band gap substantially, it alone is not enough to close the band gap. In contrast, the structural distortion induced by the alkali adsorbate plays a critical role in the gap closure. This work indicates a combined electronic and structural nature for the EI phase of the present system and the complexity of surface doping beyond charge transfer.

The formation mechanism of void in thin-walled capsule welding joint induced by HIP

Thin-walled capsule significantly impacts the overall quality of hot isostatic pressing (HIP）products, with capsule reliability being a crucial factor in determining the success or failure of the HIP process. High-temperature creep is essential for the densification of HIP powder. However, the capsule, made of dense metal, undergoes its own creep process. High temperature and high pressure may induce void formation in the capsule due to diffusion and creep. The integrity of the capsule typically relies on the welding process, and void formation at welded joints poses a significant challenge to the capsule’s reliability, increasing the likelihood of failure. This study investigates the mechanisms of void formation in welded joints during the HIP process. Results indicate that high temperature and high pressure during HIP promote the formation of two types of voids in mild steel: Kirkendall voids and creep voids. Kirkendall voids are driven by diffusion and influenced by the HIP insulation temperature, which affects their state but not their formation. Creep voids, however, originate from stress concentration at grain boundaries during creep deformation. Their distribution density is positively correlated with the degree of creep deformation, which is primarily controlled by HIP pressure and temperature.

Low-energy peak in the one-particle spectral function of the electron gas at metallic densities

Low-energy peak in the one-particle spectral function of the electron gas at metallic densities

A green and effective anti-corrosion and anti-microbial inhibitor of citric acid-based carbon dots: Experiment and mechanism analysis

Citric acid-based carbon dots (CA-CDs) with different amounts of heteroatoms N were obtained through hydrothermal synthesis method. The microstructure, optical, antibacterial and anticorrosive behaviors were systematically analyzed. Through detection, the N atoms existed in the form of pyridine-like N, pyrrole-like N and graphitic N, and promoted the grain coarsening of carbon dots. The CA-N-CDs displayed obvious pH dependence and good stability from optical behavior analysis. The antibacterial ability of citric acid-based carbon dots was improved by inserting N atom, and the antibacterial rate was directly proportional to the amount of N atom, which was up to 95% for E. coli and S. aureus. However, the anticorrosion ability showed an initial increase followed by a decrease as the amount of N atom increased, reaching its peak at CA-N12%-CDs. At this moment, the corrosion current density (icorr) of metal was 4.68 × 10−6 A/cm2, which decreased by 122 times compared with the blank solution. Meanwhile, the corrosion inhibition rate (IE) for metal was up to 96%, which mainly depended on the tight adsorption of citric acid-based carbon dots on the metal surface.