Density Of Bodies Research Articles

Vertebral body density role in determining vertebral osteoporotic fracture type and its progression.

Vertebral osteoporotic fractures (VOF) are among the most frequent fractures in the elderly, often leading to an impaired lifestyle and a high economic burden. Although a reduced bone mass density is considered one of the main risk factors for VOF, its role in determining the fracture type, using the AO spine-DGOU classification for osteoporotic thoracolumbar fractures, as well as its progression, is unknown. The current study aimed to: (1) reveal whether the bone density of the vertebral bodies of fractured and non-fractured vertebrae predicts the type of fracture, (2) examine whether bone density is associated with the initial and progressive collapse of the vertebral body, and (3) provide predictive measures for fracture progression. The study sample included 124 patients (40 males and 84 females) with an acute osteoporotic vertebral fracture who underwent a computerized tomography scan at the time of diagnosis and an x-ray at least 3 months later. The bone density of the fractured and adjacent (non-fractured) vertebrae was measured at diagnosis. The magnitude of the collapse and the progression of the fracture over time were calculated from height measurements of the vertebral bodies at diagnosis and follow-up. Age was a significant factor in predicting the fracture type and magnitude of collapse, whereas sex and bone density were not. The severity of the fracture was involved in predicting its progression, demonstrating that severe-type fractures tended to continue to collapse after diagnosis. However, when each type was examined independently, the density of the fractured vertebra had a protective effect on fracture progression. To conclude, identifying the type of fracture is beneficial in determining patient prognosis. Furthermore, the density of the fractured vertebra, the magnitude of collapse, and patient age are valuable predictors of fracture progression.

The Bulk Densities of Small Solar System Bodies as a Probe of Planetesimal Formation

Constraining the formation processes of small solar system bodies is crucial for gaining insights into planetesimal formation. Their bulk densities, determined by their compressive strengths, offer valuable information about their formation history. In this paper, we utilize a formulation of the compressive strength of dust aggregates obtained from dust N-body simulations to establish the relation between the bulk density and diameter. We find that this relation can be effectively approximated by a polytrope with an index of 0.5, coupled with a formulation of the compressive strength of dust aggregates. The lowest-density trans-Neptunian objects (TNOs) and main-belt asteroids (MBAs) are well reproduced by dust aggregates composed of 0.1 μm sized grains. However, most TNOs, MBAs, comets, and near-Earth asteroids (NEAs) exhibit higher densities, suggesting the influence of compaction mechanisms such as collision, dust grain disruption, sintering, or melting, leading to further growth. We speculate that there are two potential formation paths for small solar system bodies. One involves the direct coagulation of primordial dust grains, resulting in the formation of first-generation planetesimals, including the lowest-density TNOs, MBAs, and the parent bodies of comets and NEAs. In this case, comets and NEAs are fragments or rubble piles of first-generation planetesimals, and the objects themselves or the rubble are composed of 0.1 μm sized grains. The other path involves the further potential fragmentation of first-generation planetesimals into the compact dust aggregates observed in protoplanetary disks, resulting in the formation of second-generation planetesimals composed of compact dust aggregates, which may contribute to explaining another formation process of comets and NEAs.

Boosting Zn2+ Intercalation in High‐Performance Aqueous Zinc‐Ion Batteries with Coupling‐Induced Biphase Interface

AbstractEffectively addressing the trade‐off between fast charging kinetics and long cycle life of aqueous zinc ion batteries (AZIBs) has proven challenging due to JahnTeller distortion and high lattice strain induced by inserted Zn2+ ions in cathode structures. Herein, a hybrid cathode of NiCo2O4‐MnO2 with abundant electrochemical phase interfaces and interface coupling induced defects is developed via a simple electrochemical oxidation strategy to boost rich redox reactions. The formation of Ni─O─Mn and Co─O─Mn bonds promoted the electron transfer between the biphase interface, adjusted the electron density of the material body, effectively alleviated the electrostatic effect between Zn2+ embedding and the main frame, and further maintained the stability of the structure and alleviated the dissolution of manganese. The resulting NiCo2O4‐MnO2 cathode exhibited a high reversible specific capacity of 343.5 mA h g−1 at a current density of 100 mA g−1 and retained 95.5 % of its initial capacity after 1000 cycles at a current density of 1 A g−1. This discovery enriches insights into performance mechanisms at interfaces and paves the way for designing advanced energy storage materials.

Retinal neuroanatomy of two emerging model organisms, the spiny mouse (Acomys dimidiatus) and the Mongolian gerbil (Meriones unguiculatus)

Current research using animal models to investigate retinal cell biology and model retinal degenerative diseases largely utilize small mammals that are nocturnal and lack the ability to restore lost vision. In contrast, the Mongolian gerbil (Meriones) is a diurnal rodent with good photopic vision, and the spiny mouse (Acomys) is a small desert-dwelling rodent with remarkable regenerative capabilities. The goal of this study was to identify antibodies that detect retinal cell classes in Meriones and Acomys, and to describe the retinal anatomy of these two species in comparison to outbred laboratory mice (Mus musculus). Immunohistochemistry was performed on retinal sections with antibodies for various retinal cell types. Sections were imaged by light, fluorescence, and confocal microscopy. Cell density, morphology, and placement were compared between species qualitatively and quantitatively. Our analyses revealed a classic assembly of retinal cells in Meriones and Acomys, with a few deviations compared to Mus. Meriones displayed the highest density of cones and Acomys the lowest. A higher density of bipolar cell bodies in the proximal portion of the inner nuclear layer was observed in both Acomys and Meriones compared to Mus, and both species exhibited an increase in amacrine cell density compared to Mus. Our results provide a foundation for future research into the visual system adaptations of these interesting species.

Investigation of metal non-opaque foreign bodies of firearm origin by radiation methods

Background. The purpose is to investigate metal non-opaque foreign bodies of firearm origin. Materials and methods. Five cases of removing soft tissue foreign bodies of gunshot origin were investigated, when radiography of the limb soft tissues didn’t detect foreign bodies, but they were removed during the primary surgical wound debridement. X-ray of soft tissue gunshot wounds found no foreign bodies. To study radiographic density, foreign bodies were placed in a foam model with subsequent multislice computed tomography. For spectral analysis of metal foreign bodies, we used wavelengths unconventional for X-ray, which allowed to conduct X-ray fluorescence and X-ray structural studies. Results. Radiographic density of metal foreign bodies ranged from 989 to 2123 HU. Given the different thickness of foreign bodies, from 0.4 to 3.2 mm, the average was 1700 ± 189 HU. The foam had radiographic density of –969 HU with model dimensions of 200 × 100 × 50 mm. When examining samples of foreign bodies, it was found that they are deformed, have different thicknesses. One of the samples is light and smooth on one side, and dark and rough on the other. X-ray fluorescence results: composition on the light side (% by mass): Al — base, Mn — 0.8, Fe — 0.3, Zn — 0.1, Cr — 0.05, Ti — 0.2, corresponding to Al-Mn alloy. The dark side is an oxidized Al-Mn alloy. In the spectrum of the dark side of the sample, the Br-Kα line was detected, which indicates the participation of bromine compounds in the oxidation process. From the smooth side of the sample, the spectrum of this line is not determined. Conclusions. Non-opaque metal foreign bodies of gunshot origin are a rare phenomenon. Metal foreign bodies with low radiographic density are non-ferromagnetic, the use of modern magnetic surgical instruments will not be effective. Visualization of metal foreign bodies, which are not determined by radiography, is possible with the help of multislice computed tomography. The use of the wavelength of primary radiation, which is unconventional for X-ray spectral analysis, and original X-ray optical schemes allows for quantitative determination of the composition and structure of any metal foreign bodies.

MSCT-semiotics of vertebrae in patients with cervical spine stenosis

Introduction The number of surgical interventions on the cervical spine for stenosis has been constantly increasing. This fact proves that there is a need for careful preoperative preparation that would consider the complexity of the intervention and the age of the patients.Purpose To substantiate the need to include the MSCT data processing algorithm of bone tissue density of vertebral bodies and arches to assess their quality for planning osteoplastic decompressive laminoplasty in patients with cervical spine stenosis due to degenerative changes.Material and methods This single-center retrospective study investigated qualitative and quantitative characteristics of the spine with radiography and multislice computed tomography (MSCT) in 82 patients with degenerative diseases of the cervical spine and associated spinal canal stenosis (CSS).Results and discussion The data obtained indicate a tendency for the total density of the cervical vertebrae to increase from C3 to C5 and to decrease caudally, with minimal density in C7 without signs of osteoporosis. A similar trend is characteristic of trabecular bone. The density of the osteon layer of the vertebral arch cortex differs significantly from the density of the outer and inner plates. The total density of the compact layer of the vertebral arch cortex exceeds 785.15 ± 38.4 HU.Conclusion The data obtained justify the need to include the study of the density of vertebral bodies, vertebral arches, and its thickness in the MSCT data processing algorithm to develop a plan for surgical intervention in patients with cervical spine stenosis in order to obtain objective data on the quality of the bone.

Mathematical modeling of foreign bodies with different density in biological and non-biological models in the experiment

Background. Modeling allows investigating both existing and predicted processes and is widely used in basic science and in many industries. The aim is to develop a mathematical model for determining the size of the foreign bodies (FB) and their radiographic density in non-biological and biological models to improve the results of diagnosis for gunshot ricochet wounds. Materials and methods. In the biological non-living model (a piece of pork) and non-biological models (polystyrene, foam rubber), we place the FB made of paper, leather, rubber, plastic, and lithium-ion batteries. The number of the FB is 9 of each type. Number of models is 3 each: pork, polystyrene, foam rubber. We measure the dimensions of the FB and models with a metric ruler. For each model, we select the FB, which we label with the study number. We immerse the FB to the same depth using a Billroth general surgical medium hemostatic clamp in the following sequence: paper, leather, rubber, plastic, and lithium-ion battery. Multislice computed tomography (MSCT) of the models is performed on the Revolution EVO (2021) apparatus with measurement of the sizes and radiographic density of the FB and models. Radiographic density was measured in conventional units on the Hounsfield scale. For each study group, the ratio of the actual sizes of the removed FB and according to MSCT data was determined in the MathCad 15 computer math software, depending on the radiological density of the FB and the model. Results. According to MSCT data, the radiographic density of the models on the Hounsfield scale is as follows: polystyrene — –990.0 ± 0.3 units; foam rubber — –985.0 ± 0.2 units; pork — 62.0 ± 0.3 units; radiographic density of the foreign bodies: paper — –743.0 ± 10.3 units, leather — –258.0 ± 14.2 units, rubber — –12.0 ± 2.6 units, plastic — 183.0 ± 14.6 units, lithium-ion batteries — 3071 units. Visualization of paper in non-biological and biological models and leather in non-biological models is problematic due to the similar radiographic density of the models and the inability to measure the dimensions. When the FB (rubber, plastic, battery) is immersed in polystyrene, the coefficient of length (CL) is 1.0612, the coefficient of width (CW) is 1.928; in foam rubber: CL is 0.9926, CW is 1.9641; in pork: CL is 0.8394, CW is 1.534. Comparing the average coefficients of the ratio (CL and CW), we find that the coefficient in a biological model is closest to 1. This means that the FB from rubber, plastic, and batteries are best detected in pork. Conclusions. The actual dimensions of the FB placed in biological and non-biological models differ from those obtained by MSCT. Data correction is performed through calculated coefficients for length and width. The radiographic density of the model affects the radial visualization of the FB. The use of mathematical modeling in determining the sizes and radiographic density allows reducing the measurement error and determine the structure of the FB.

Liquefaction characteristics of aging earth dam body by dynamic centrifugal model test

Earth dams have been damaged or even collapsed owing to earthquake liquefaction. Although a liquefied foundation is a major factor affecting the safety of earth dams, the damage caused by the liquefaction of the dam body itself cannot be ignored, particularly for aged earth dams. However, in the presence of high water levels, liquefaction of the dam body cannot be considered solely in terms of the seismic load. Consequently, in this study we used dynamic centrifuge tests and numerical analysis to simulate the liquefaction process of an earth dam body under high water levels and analyzed the damage mechanism. The aging dam body, which can be easily liquefied, was simulated by controlling the density of the dam body, the low-density dam body exhibiting greater acceleration-amplification characteristics and displacement. Liquefaction was evident in the contact area between the slope and water level, with segmental settlement occurring. Through numerical analysis, it was evident that the core area accumulated considerable plastic deformation, and the sliding damage extended from the water contact surface to the dam toe. This study could compensate for the dearth of liquefaction model experiments of earth dams, providing a necessary reference for the seismic reinforcement of earth dams.

Modelling of spacecraft apparent brightness A study on OneWeb constellation satellites

Artificial satellites orbiting around the Earth, under certain conditions, result to be visible even to the naked eye. The phenomenon of light pollution jeopardises the researching activities of the astronomical community: traces left by the objects are clear and evident and images for scientific purposes are damaged and deteriorated.The development of a mathematical model able to estimate the satellite’s brightness is required and it represents a first step to catch all the aspects of the reflection phenomenon. The brightness model (by Politecnico di Milano) will be exploited to implement a realistic simulation of the apparent magnitude evolution and it could be used to develop an archetype of new-generation spacecraft at low light-pollution impact.Starting from classical photometry theory, which provides the expressions of radiant flux density of natural spherical bodies, the global laws describing flux densities and the associated apparent magnitude are exploited to generalise the analysis. The study is finally focused on three-dimensional objects of whatever shape which can be the best representation of the spacecraft geometry. To obtain representative results of the satellite brightness, a validation process has been carried on. The observation data of OneWeb satellites have been collected by GAL Hassin astronomical observatory, settled in Isnello, near Palermo. The observations were carried out in order to map the satellites brightness at various illumination conditions, also targeting a single satellite across its different positions on the sky (i.e., during its rise, culmination and setting).A model aiming to estimate brightness of mega-constellation satellites (developed by Politecnico di Milano) has not been developed yet.

Fractal study on the nonlinear seepage mechanism during low-permeability coal water injection

In the initial stage of coal seam water injection, due to the high density and low permeability of coal bodies, an obvious startup pressure gradient is observed in relation to water seepage; this phenomenon leads to low-velocity nonlinear seepage. In this paper, we study the nonlinear seepage law and the main influencing parameters of the water injection process. First, based on the startup pressure gradient, the nonlinear seepage equation, and the fractal theory, we formulated a nonlinear seepage model of coal seam water injection that considered the fractal characteristics of a complex coal structure. Subsequently, we carried out coal seam water injection and gas radial seepage experiments under a high overburden pressure, obtaining the startup pressure gradient according to the seepage characteristics and the changes of dynamic parameters. Then, the dynamic parameters of water injection, the structural parameters of the coal samples, the physical parameters, and the fractal dimension were substituted into the theoretical model to obtain the theoretically calculated value. Finally, through comparative analysis of theoretical and experimental startup pressure gradient calculation results, it is found that with the increase in the overburden pressure, the permeability of coal and the connectivity effect are reduced, while the fracture tortuosity and the startup pressure gradient increase. Moreover, coal seam permeability does not seem to be the single decisive factor for the nonlinear startup pressure gradient.

Bone Mineral Density in Field Hockey Players: A Systematic Review.

The aim of this study was to carry out a systematic review to compare and analyse the bone mineral density of field hockey players of both sexes and of different ages, with other sports and with a sedentary population. The search process was carried out using the PubMed, SPORTDiscus, Web of Science and Scopus databases. The search ended on 18 March 2024. We selected articles in which a comparison was made of bone mineral density of the whole body, lumbar spine, femoral neck, arms and legs, among field hockey players, and/or with other sports and/or with a sedentary population. The systematic review followed the guidelines described in the 2020 PRISMA statement. The initial search identified 220 articles. After applying the inclusion and exclusion criteria, the search was narrowed down to seven articles in total. It was observed that the field hockey group had better bone mineral density values than sedentary population and the low-impact sports population. Basketball players had better whole body and leg bone mineral density values than field hockey players. Causality could not be established due to the cross-sectional nature of the included studies. The better bone mineral density values in field hockey players compared to the sedentary population may be because people who participate in impact sports have a better bone mineral density. The differences in bone mineral density between field hockey and low-impact sports could be related to a lower impact during their practice in these disciplines.

Fabrication of highly transparent yttria by DLP-based additive manufacturing

High-quality transparent yttria (Y2O3) is produced using various shaping techniques; however, the geometric control limits of shaping processes hinder its utilization and application. Thus, this study proposed digital light processing (DLP)-based additive manufacturing (AM). Although popular, transparent ceramic AM faces issues owing to limited transparency and simple shapes. This study fabricated a three-dimensional-structured transparent Y2O3 ceramic using DLP-based AM assisted by vacuum sintering and revealed the critical factors governing its transparency. Zirconia and lanthana were utilized as sintering additives to regulate grain growth. Slurry conditions (dispersant concentration and solid loading) were optimized to control the homogeneity and density of the green body. After pre-sintering and vacuum sintering, the transparent Y2O3 ceramics exhibited a transmittance of 94.86 % of the theoretical limit and a relative density of 99.89 % owing to a fine-grained dense microstructure. The fabricated lens array structures of Y2O3 demonstrated a notable level of transparency and satisfactory optical imaging capabilities.

Bone mineral density of the incus body and long process in patients with chronic otitis media and its relationship with functional outcome in type II tympanoplasty

Background Inflammatory conditions such as chronic otitis media (COM) can cause irreversible impairments in the microarchitecture and functions of the incus, which subsequently leads to conductive hearing loss. Objectives To investigate bone mineral density (BMD) of the incus body (IB) and long process (ILP) on preoperative temporal CT in COM patients with and without incudo-stapedial joint discontinuity (ISJD), and also to determine the association between BMD values and the postoperative air-bone gap (ABG) in the ISJD group. Material and methods The mean IB density (IBD)/occipital bone density (OBD) and ILP density (ILPD)/OBD values were compared between the patients with and without ISJD. The correlation between ABG gain and preoperative incus density values was assessed in the ISJD group. Results The mean IBD/OBD and ILPD/OBD values were significantly higher in patients with intact ISJ. There was a moderate positive correlation between postoperative ABG gain and ILPD/OBD values in the ISJD group. Conclusion and significance The decrease in BMD of the incus may involve ILP as well as IB in patients with ISJD caused by ILP lysis in COM. A higher preoperative ILPD/OBD was correlated with a higher postoperative ABG gain in COM patients with ISJD.

Analysis of environmental factors influencing lumpy skin disease outbreak seasonality and assessment of its spread risk in the Saratovskaya oblast of Russia.

Lumpy skin disease (LSD) is a transboundary viral disease of cattle that causes serious economic losses due to a significant decrease in meat and milk productivity. This study analyzed the influence of natural and anthropogenic environmental factors on LSD spread seasonality and assessed the risk of LSD outbreaks in the Saratovskaya oblast of the Russian Federation. Data on LSD outbreaks and environmental factors during different seasons were collected for the period 2011-2020 in the Balkan Peninsula, Middle East, and Russia. Risk assessment was performed using mathematical modeling with generalized linear regression and maximum entropy. Fourteen statistically significant environmental factors influencing LSD spread were identified. The analysis of MaxEnt models built using the selected factors showed that the presence of the pathogen is mostly exerted by: the density of susceptible cattle (an increased risk is observed at a density above 10 and 20 heads/10 km2 in winter and autumn, with a permanent risk in spring and summer), the density of water bodies (the risk is increased at any density in winter and autumn, in the range of 13-23.5 m2/km2 in spring, in the ranges of 0-8 and over 14.5 m2/km2 in summer), and average monthly precipitation rate (the most risky are 105-185 mm/month in winter, 35 mm in spring, 15-105 mm in summer, and above 50 mm in autumn). LSD tends to spread during the warm season. Compared with other test zones, the Saratovskaya oblast has a negligible risk of disease spread (in winter), low risk (in spring), or medium risk (in summer and autumn). The annual risk is low to medium.

High strength and high toughness Csf/SiC composites prepared by laser powder bed fusion/ reactive melt infiltration with the impregnation of boron-and silicone-containing phenolic resin

Laser powder bed fusion (LPBF) has emerged as an effective method for preparing complex structured silicon carbide (SiC) ceramics. However, the SiC components demonstrate low strength and high brittleness, which remain major challenges limiting its application. To overcome this limitation, short carbon fiber reinforced silicon carbide (Csf/SiC) composites are prepared by combining LPBF and phenolic resin binder impregnation (PRBI)-reactive melt infiltration (RMI), in which high char yield boron-and silicone-containing phenolic resin (BSiPF) impregnation is used to adjust the carbon density of green bodies and to reduce the pore size of green bodies. By optimizing the impregnation process, the carbon density can be brought close to the theoretical optimal value of 0.84 g/cm3, and the reduction of the pore size is conducive to the improvement of the reaction rate at the early stage of the reaction, which enhance the SiC phase content of Csf/SiC composites obtained by RMI. Meanwhile, the application of BSiPF results in a protective pyrolytic carbon (PyC) coating on the surface of Csf, which can reduce the erosion of Csf by molten Si during the RMI process, thus improving the fracture toughness of Csf/SiC composites. The final Csf/SiC composites exhibit the enhanced bulk density, bending strength and fracture toughness, reaching 2.90 ± 0.01 g/cm3, 257 ± 20 MPa, 3.52 ± 0.15 MPa m1/2, respectively. This study provides a new strategy for effective impregnation technique for the additive manufacturing (AM) of high strength and high toughness SiC composites.

Phenotypically concordant distribution of pick bodies in aphasic versus behavioral dementias

Pick’s disease (PiD) is a subtype of the tauopathy form of frontotemporal lobar degeneration (FTLD-tau) characterized by intraneuronal 3R-tau inclusions. PiD can underly various dementia syndromes, including primary progressive aphasia (PPA), characterized by an isolated and progressive impairment of language and left-predominant atrophy, and behavioral variant frontotemporal dementia (bvFTD), characterized by progressive dysfunction in personality and bilateral frontotemporal atrophy. In this study, we investigated the neocortical and hippocampal distributions of Pick bodies in bvFTD and PPA to establish clinicopathologic concordance between PiD and the salience of the aphasic versus behavioral phenotype. Eighteen right-handed cases with PiD as the primary pathologic diagnosis were identified from the Northwestern University Alzheimer’s Disease Research Center brain bank (bvFTD, N = 9; PPA, N = 9). Paraffin-embedded sections were stained immunohistochemically with AT8 to visualize Pick bodies, and unbiased stereological analysis was performed in up to six regions bilaterally [middle frontal gyrus (MFG), superior temporal gyrus (STG), inferior parietal lobule (IPL), anterior temporal lobe (ATL), dentate gyrus (DG) and CA1 of the hippocampus], and unilateral occipital cortex (OCC). In bvFTD, peak neocortical densities of Pick bodies were in the MFG, while the ATL was the most affected in PPA. Both the IPL and STG had greater leftward pathology in PPA, with the latter reaching significance (p < 0.01). In bvFTD, Pick body densities were significantly right-asymmetric in the STG (p < 0.05). Hippocampal burden was not clinicopathologically concordant, as both bvFTD and PPA cases demonstrated significant hippocampal pathology compared to neocortical densities (p < 0.0001). Inclusion-to-neuron analyses in a subset of PPA cases confirmed that neurons in the DG are disproportionately burdened with inclusions compared to neocortical areas. Overall, stereological quantitation suggests that the distribution of neocortical Pick body pathology is concordant with salient clinical features unique to PPA vs. bvFTD while raising intriguing questions about the selective vulnerability of the hippocampus to 3R-tauopathies.

Quantum algorithms to compute the neighbour list of N-body simulations

One of the strategies to reduce the complexity of N-body simulations is the computation of the neighbour list. However, this list needs to be updated from time to time, with a high computational cost. This paper focuses on the use of quantum computing to accelerate such a computation. Our proposal is based on a well-known oracular quantum algorithm (Grover). We introduce an efficient quantum circuit to build the oracle that marks pairs of closed bodies, and we provide three novel algorithms to calculate the neighbour list under several hypotheses which take into account a-priori information of the system. We also describe a decision methodology for the actual use of the proposed quantum algorithms. The performance of the algorithms is tested with a statistical simulation of the oracle, where a fixed number of pairs of bodies are set as neighbours. A statistical analysis of the number of oracle queries is carried out. The results obtained with our simulations indicate that when the density of bodies is low, our algorithms clearly outperform the best classical algorithm in terms of oracle queries.

Study on microstructures, properties and mechanisms of sinter-joining refractory metal W[sbnd]30Si powders and sputtering targets by spark plasma sintering technique

The development of semiconductor integrated circuits has been limited by the low utilization rate of refractory metal sputtering targets. Spark plasma sintering (SPS) technology has shown great superiority in the sintering and joining of materials, which can be applied to the repair of waste targets and improve the utilization rate. In this study, SPS technology was used to sinter-join the high-purity refractory metal W30Si sputtering powder and the target for integrated circuits to determine the optimal repair process and repair mechanism. The morphological characteristics, grain size, relative density, and Vickers hardness of the repair layer (powder-sintered body) and the target under different joining times were analyzed, and the interface structure and properties of the W30Si joint were also studied. It was found that the W30Si joint was composed of WSi2 and Si phases. The grain size, relative density, and Vickers hardness of the W30Si powder-sintered body and targets increased with the joining time. When the joining time was 10 min (1200 °C), the W30Si joint formed a “zigzag” joining interface, and the bending strength, relative density, grain size, Vickers hardness, and thermal conductivity of the joint were similar to those of the pristine target. In addition, the physical model of SPS sintered and joined refractory metal powders and targets was constructed. Studies have shown that the sinter-joining consists of three stages: early stage, middle stage, and late stage. Among them, the middle stage included two steps that may occur simultaneously, namely the sintering of refractory metal powders and the joining of refractory metal powders with the target, involving pressure welding, micro-arc welding, resistance welding, and diffusion welding mechanisms. This work can provide theoretical guidance for the optimal design of the SPS repair process for refractory metal W30Si sputtering targets.

Ventilation shutdown and the breath-taking violence of infectious disease emergency management in industrial livestock production

Powerful ventilation systems are a crucial technology in industrial livestock production, mitigating the unhealthy ambient conditions that result from great densities of animal bodies, biowastes, and chemical agents, and enabling the rapid production of massive quantities of flesh and eggs in such crowded indoor spaces. But bad air is just one of many biophysical and technoscientific challenges managed in these spaces, chief among them the ever-present risks of infectious disease transmission and evolution that threaten animal health and productivity and pose untold risks for humans. This article examines the intersection of these two central problems, where ventilation systems that are normally used to manage bad air within enclosures have been repurposed in the context of disease outbreaks to quickly and cheaply kill infected populations by hyperthermia. An analysis of this nascent practice, euphemistically termed “ventilation shutdown,” shows how governments and publicly funded scientific institutions have worked with private industry to develop and systematize the use of this and other technologies of mass death to respond to infectious disease emergencies, a dynamic that, we argue, sheds new light on both the precarity and the violence of industrial livestock production.

Investigations on the seepage characteristics of polymer grouting body for repairing HDPE geomembrane defects based on LF NMR

As high-density polyethylene (HDPE) geomembranes in landfill liner systems increasingly age and damage, seepage incidents frequently occur and severely threaten the surrounding ecological environment and groundwater safety. Targeted injection grouting with polymer materials can rapidly restore the barrier function by repairing defects in damaged geomembranes. To investigate the sealing mechanisms of polymer grouting bodies with various densities, this study used low-field nuclear magnetic resonance (LF NMR) techniques to monitor and visualize the permeation process within the grouting bodies. The results revealed two failure modes of the grouting bodies under water flows: 1) insufficient interfacial shear strength between the low-density polymer and geomembrane, leading to interfacial leakage; 2) gradual buildup of permeation pressure puncturing the foam cells of the polymer matrix and inducing permeation channels. Selecting polymers with suitable expansion ratios to produce appropriate expansive pressures is crucial to enhance interfacial shear strength while avoiding secondary damages to geomembranes. Increasing the density of the polymer grouting body can also enhance the compressive strength of foam cells and interfacial shear resistance. These are crucial for enabling grouting repair of defects in geomembranes and improving their barrier performance.