Search Results (93)

The manufacture of barium sulfide or barium salts (BaS, BaCl₂, Ba (OH)₂, among others) requires high-purity barite ores (>90%). In this study, a new method to produce barium sulfide from low-grade barite ores (60% purity) is proposed. The method involves gravitational concentration of barite ore on a shaking table followed by mechanical activation of the barite concentrate with metallurgical coke in a ball mill. The mechanically activated mixture undergoes carbothermic reduction with an argon flow, resulting in the conversion of barite concentrate into barium sulfide. Gravitational concentration studies conducted using a shaking table demonstrated that, upon optimizing key operational parameters—namely, the wash-water flow rate, length, stroke frequency, the splitter positions of the concentrate, middlings, and tailings—a barite concentrate with a purity exceeding 95% BaSO₄ was successfully achieved. Mechanical activation of the barite/coal mixture lowered the initial temperature of the carbothermic reduction from 1100 K to 990 K, enabling complete conversion of barite to BaS, as confirmed by thermogravimetric curves and XRD analysis. Furthermore, the activation energy during the carbothermic reduction ranged from 300 to 500 kJ/mol, suggesting a complex reduction process of barite with metallurgical coke that is difficult to represent by a single reaction. Full article

This study of the BaSO₄-Bi phosphor has revealed that the accumulated energy after external optical excitation exhibits specific characteristics. During irradiation with photon energy exceeding the bandgap, in addition to the intrinsic ultraviolet emission of the Bi³⁺ ion, several recombination emissions and emission from the Bi²⁺ ion are observed. At 80 K, the recombination luminescence states and Bi²⁺ ion emission form combined electronic states. Upon heating of the BaSO₄-Bi phosphor, these combined electronic states decay into recombination emissions at 2.34 eV, 2.4 eV, 3.1 eV, and 2.7 eV, as well as Bi²⁺ ion emission at 1.97 eV. It is assumed that the 2.34 eV, 2.4 eV, and 3.1 eV emissions are associated with the recombination of electrons released from ionized ${SO}_4^{3-}$ electron trapping centers with nonequivalently localized holes in the host lattice. The 2.7 eV emission is attributed to the decay of an exciton formed by electron–hole recombination near a Bi³⁺ ion. Full article

Petroleum is an indispensable energy source in modern industrial society, and maintaining the safe and stable operation of its injection and production system is of great significance. To analyze the mechanism of pipeline damage caused by corrosion and scaling in the injection production system, taking a water injection pipeline in an oil field as an example, the causes of corrosion and scaling damage were studied by detecting pipeline samples and analyzing corrosion products and various service conditions of the pipeline. The results showed that there was more scaling on the inner wall of the pipeline, and there was local corrosion in the pipeline sections that had experienced water injection, shutdown, and gas injection conditions, while there was no significant corrosion thinning in the pipeline sections that had only experienced water injection and shutdown conditions. The scale layer formed under water injection conditions is mainly composed of barium strontium sulfate (Ba_0.75Sr_0.25SO₄), barium sulfate (BaSO₄) and a small amount of silica (SiO₂). The main reason for scale formation is the high content of barium ions (Ba²⁺) in the injected water. The corrosion products formed under gas injection conditions, including strontium ions (Sr²⁺) and sulfate ions (SO₄²⁻), are mainly composed of ferrous carbonate (FeCO₃) and ferric oxide (Fe₂O₃). The pipeline corrosion product FeCO₃ is mainly caused by carbon dioxide (CO₂) in the medium. In addition, the high liquid content, cecal position, high Cl⁻ (chloride ion) content, and slightly acidic environment in the pipeline also accelerate the occurrence of corrosion damage. The Fe₂O₃ in the corrosion products is formed when the pipeline is exposed to air after sampling, and is not the main cause of pipeline corrosion. Full article

This trial aimed to investigate the effects of compound essential oils (EO) on the fattening performance, blood physiological–biochemical indices, and intestinal microbiota in late-fattening Simmental crossbred bulls. Twenty healthy Simmental crossbred bulls (Simmental × Charolais × Angus) with similar initial body weights of 442 (±72.49) kg were randomly divided into two groups: a control group (basal diet, CON group) and a compound essential oil group (basal diet + 16 g/head/day, EO group). The trial included a 14-day pre-feeding period and a 42-day experimental period, totaling 56 days. The results showed the following: (1) The EO group exhibited a significantly higher average daily gain (ADG), immunoglobulin A (IgA), immunoglobulin G (IgG), total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-PX), glucose (GLU), dopamine (DA), basophil count (Baso), mean corpuscular hemoglobin (MCH), and platelet distribution width (PDW) compared to the CON group (p < 0.05), while the mean corpuscular volume (MCV) was significantly lower (p < 0.05). (2) Although the compound essential oil supplementation did not alter the relative abundance of major intestinal microbial taxa, it significantly improved the intestinal microbiota structure (p < 0.05), increased fiberdegrading microbiota, and promoted short-chain fatty acid production. (3) The relative abundance of the intestinal microbiota norank_f__UCG-010 showed significant positive correlations with ADG, GSH-PX, IgG, DA, T-SOD, GLU, IgA, and Baso (p < 0.05), while Christensenellaceae_R-7_group abundance was positively correlated with ADG, IgA, and Baso (p < 0.05). In conclusion, the compound essential oil enhances healthy and efficient fattening in beef cattle by improving the intestinal microbial structure, increasing beneficial bacteria, regulating the nutrient metabolism through key bacterial genera, and enhancing the immune function, antioxidant capacity, and energy metabolism levels. Full article

Sustainable hydrocarbons are one of the main methods of decreasing the use of fossil fuels and derivatives, contributing to the mitigation of environmental impacts and greenhouse gas emissions. Circular economic concepts focus on reusing waste by converting it into new products, which are then input again into industrial production lines, thus decreasing the necessity of fossils. Polypropylene-based plastic waste can be depolymerized into smaller chemical chains, producing a liquid phase rich in hydrocarbons. In the same way, triacylglycerol-based waste biomasses can also be converted into renewable hydrocarbons. Our research studied the co-processing of polypropylene (PP) and cottonseed oil dreg (BASOs) waste from the biodiesel industry using a micropyrolysis system at 550 °C, previously validated to predict the scale-up of the process. PP showed the production of alkanes and alkenes, while BASOs also produced carboxylic acids in addition to the PP products. The main impacts were observed in the conversion yields, reaching the highest values of pyrolytic liquid (64%), gas (14%), and solid product (13%) compared to the co-processing mixture of BASO:PP (1:2). Also, in this mixture, the production of carboxylic acids decreased to the lowest value (~10%), improving the conversion to sustainable hydrocarbons. Full article

Polyetheretherketone (PEEK) is a high-performance, biocompatible polymer with remarkable mechanical properties, making it a promising candidate for medical implants. However, its intrinsic radiolucency poses a challenge for post-operative imaging. This study investigates the photon shielding capabilities and X-ray imaging qualities of pure PEEK and its composites with barium sulfate (BaSO₄), tantalum (Ta), bismuth oxide (Bi₂O₃), and hydroxyapatite (HA). The Monte Carlo-based Geant4 toolkit and the EpiXS application were used to evaluate key photon interaction parameters, including mass attenuation coefficients, effective atomic number (Z_eff), and effective electron density (N_eff), as well as the imaging performance metrics such as energy deposition and signal-to-noise ratio (SNR). Results indicate that high atomic number composites significantly enhance PEEK’s photon attenuation and imaging contrast. PEEK-Bi₂O₃ exhibited the highest attenuation coefficients and energy deposition, making it the most effective X-ray shielding material. PEEK-Ta provided a balanced performance with enhanced shielding and lower secondary radiation effects, making it suitable for applications requiring both radiopacity and imaging stability. PEEK-BaSO₄ moderately improved attenuation while maintaining a lower density, offering a trade-off between radiopacity and mechanical properties. Conversely, PEEK-HA demonstrated minimal enhancement in photon attenuation, limiting its effectiveness for radiographic applications. The findings suggest that incorporating high atomic number elements into PEEK significantly enhances its suitability for radiopaque medical implants, allowing for improved post-operative monitoring. Full article

In this research, polymer composite sheets were developed by blending poly (vinylidene fluoride-co-hexafluoropropylene) or P(VDF-HFP) with varying concentrations of barium sulfate (BaSO₄) for X-ray shielding applications. The photon counting technique was used to evaluate the composite shielding characteristics through the linear attenuation coefficient. Surface properties, including surface morphology, hydrophobicity, and surface energy, were analyzed using an atomic force microscope (AFM) and a water contact angle machine. Scanning electron microscopy (SEM) was employed to investigate the microstructural distribution and dispersion of BaSO₄ particles within the polymer matrix, providing insights into the composite’s uniformity and structural integrity. Additionally, the bulk properties of the composite polymer sheets, such as crystal structures, tensile strength, and thermal stability, were examined. The results demonstrate that increasing the concentration of BaSO₄ in BaSO₄/P(VDF-HFP) composite sheets significantly improves their X-ray attenuation capabilities. Moreover, higher BaSO₄ concentrations enhance the material’s hydrophobicity, flexibility, and thermal stability, highlighting the potential of these composites for advanced radiation shielding applications. Full article

Sensor miniaturization offers significant advantages, including enhanced SoC integration efficiency, reduced cost, and lightweight design. While the roll-to-roll printed electronics fabrication process is advantageous for the mass production of sensors compared to the traditional MEMS technology, producing sensors that require air gap-based 3D structures remains challenging. This study proposes an integration of roll-to-roll gravure printing with a transferring and bonding method for touch sensor fabrication. Unlike previously reported methods for sacrificial layer removal, this approach prevents stiction issues, thus enabling sensor miniaturization and providing the flexibility to select materials that minimize sensitivity degradation during scaling. For the lower part of the sensor, Ag and BaSO₄ were roll-to-roll gravure-printed on a flexible PET substrate to form the bottom electrode and dielectric layer, followed by BaSO₄ spin coating on the sensor’s anchor area to form a spacer. For the upper part, a water-soluble PVP sacrificial layer was roll-to-roll gravure-printed on another flexible PET substrate, followed by spin coating Ag and SU-8 to form the top electrode and the structural layer, respectively. The sacrificial layer of the upper part was removed with water to delaminate the top electrode and structural layer from the substrate, then transferred and bonded onto the spacer of the lower part. Touch sensors of three different sizes were fabricated, and their performances were comparatively analyzed along with that of an epoxy resin-based sensor, demonstrating that our sensor attained miniaturization while achieving relatively high sensitivity. Full article

Background/Objectives: Diffuse myocardial fibrosis and altered deformation are relevant prognostic factors in aortic stenosis (AS) patients. The aim of this exploratory study was to investigate the relationship between myocardial strain, and myocardial extracellular volume (ECV) in patients with severe AS with a photon-counting detector (PCD)-CT. Methods: We retrospectively included 77 patients with severe AS undergoing PCD-CT imaging for transcatheter aortic valve replacement (TAVR) planning between January 2022 and May 2024 with a protocol including a non-contrast cardiac scan, an ECG-gated helical coronary CT angiography (CCTA), and a cardiac late enhancement scan. Myocardial strain was assessed with feature tracking from CCTA and ECV was calculated from spectral cardiac late enhancement scans. Results: Patients with cardiac amyloidosis (n = 4) exhibited significantly higher median mid-myocardial ECV (48.2% versus 25.5%, p = 0.048) but no significant differences in strain values (p > 0.05). Patients with prior myocardial infarction (n = 6) had reduced median global longitudinal strain values (−9.1% versus −21.7%, p < 0.001) but no significant differences in global mid-myocardial ECV (p > 0.05). Significant correlations were identified between the global longitudinal, circumferential, and radial strains and the CT-derived left ventricular ejection fraction (EF) (all, p < 0.001). Patients with low-flow, low-gradient AS and reduced EF exhibited lower median global longitudinal strain values compared with those with high-gradient AS (−15.2% versus −25.8%, p < 0.001). In these patients, the baso-apical mid-myocardial ECV gradient correlated with GLS values (R = 0.28, p = 0.02). Conclusions: In patients undergoing PCD-CT for TAVR planning, ECV and GLS may enable us to detect patients with cardiac amyloidosis and reduced myocardial contractility Full article

Medical tubing, particularly cardiovascular tubing, is a critical area of research where continuous improvements are necessary to advance medical devices and improve patient care. While polymers are fundamental for these applications, on their own they present several limitations such as insufficient X-ray contrasting capabilities. As such, polymer composites utilizing radiopaque fillers are a necessity for this application. For medical tubing in vivo, radiopacity is a crucial parameter that virgin polymers alone fall short in achieving due to limited X-ray absorption. To address this shortcoming, inorganic radiopaque fillers such as barium sulphate (BaSO₄) and bismuth oxychloride (BiOCl) are incorporated into polymer matrices to increase the X-ray contrast of the manufactured tubing. It is also known, however, that the incorporation of these fillers can affect the mechanical, physical, and thermal properties of the finished product. This research evaluated the impact of incorporating the two aforementioned fillers into Pebax^® 6333 SA01 MED at three different loading levels (10, 20, and 30 wt.%) on the physical, thermal, and mechanical properties of the composite. Composites were prepared by twin screw extrusion and injection molding followed by characterization of the mechanical (tensile, impact, and flexural), thermal (DSC), rheological (MFI), and physical (density and ash content) properties. The performed analysis shows that BiOCl enhanced the aesthetic properties, increased stiffness, and maintained flexibility while having minimal impact on the tensile and impact properties. When comparing BiOCl to BaSO₄-filled composites, it was clear that depending on the application of the polymer composite, BiOCl may provide more desirable properties. The study highlights the importance of optimizing filler concentration and processing conditions to achieve desired composite properties for specific medical applications. Full article

A series of Fe–Ba mixed oxides, including a pure Fe-containing sample as a reference, have been synthesized via a sol–gel process using Fe³⁺ or Fe²⁺ salts and BaSO₄ as raw materials, with Pluronic P123 serving as a template. These oxides have been thoroughly characterized and subsequently utilized as catalysts for the chlorination of various organic molecules. Commercial hydrochloric acid, known for its relative safety, and environmentally friendly aqueous hydrogen peroxide were employed as the chlorine source and oxidant, respectively. The pure Fe-containing catalyst displays excellent thermal stability between 600 and 800 °C and exhibited moderate to high conversions in the chlorination of toluene, benzene, and tert-butyl hydroperoxide, with remarkable ortho-selectivity in chlorination of toluene. The combination of Fe³⁺ salt with BaSO₄ in the sol–gel process results in a Fe–Ba mixed oxide catalyst composed of BaO₂, BaFe₄O₇, and Fe₂O₃, significantly enhancing the chlorination activity compared to that displayed by the pure Fe catalyst. Notably, the chlorination of tert-butyl hydroperoxide (TBHP) does not require additional oxidants such as H₂O₂, and involves both electrophilic substitution and nucleophilic addition. Notably, the chlorination of bromobenzene yields chlorobenzene as the sole product, a transformation that has not been previously reported. Overall, this catalytic chlorination system holds promise for advancing the chlorination industry and enhancing pharmaceutical production. Full article

Can the foamability of surfactant aqueous solutions be controlled chemically? Well-known antifoams can prevent foaming by inducing the coalescence of the bubbles, but can the surfactants be deactivated chemically? If yes, how does this affect the surface tension of their aqueous solutions and their foaming capacity? To shed a light on these fundamental questions, we chose a well-known surfactant containing in its molecule a sulfate group (Sodium dodecyl sulfate, SDS) and mixed it with BaCl₂, (the solubility of BaSO₄ is 0.245 mg/100 mL water, T = 20 °C), Pb(NO₃)₂ (the solubility of PbSO₄ is 40.4 mg/100 mL water, T = 25 °C) and FeCl₃ (the solubility of Fe₂(SO₄)₃ is 25.6 g/100 mL water, T = 20 °C) at different molar ratios (MX_n/SDS): 1/2, 1/1, 2/1, 4/1. The results were surprising: in the case of BaCl₂, despite being in stoichiometric molar ratio with SDS (BaCl₂ + 2SDS -> Ba(DS)₂ + 2 NaCl), or in excess of BaCl₂, which should convert the whole amount of SDS into a sediment, the surface tension value remained significantly lower than that of the single surfactant. At the same time, foamability was either low or absent. It therefore appears that all of the surfactants should be converted into a sediment with very small solubility, but the low surface tension indicates the opposite. The lack of foamability indicated the opposite of that opposite. With Pb(NO₃)₂ and FeCl₃, the results are even stranger. The surface tension values are substantially smaller than those of the single surfactants, and at the same time, low foamability or lack of foamability was observed. It appears that the surfactant exists and at the same time does not exist in the aqueous solution. Where is the truth? Future studies will shed a light. Full article

A barium-rich Celestine (Sr,Ba)SO₄ concentrate from the primary Mexican ore production was used as a thickening agent to produce closed-cell Zn-22Al-2Cu alloy foams, while calcium carbonate was used as a foaming agent. The microstructure and mechanical properties of the foams were analyzed by optical microscopy, scanning electron microscopy, and compression tests, respectively. The Zn-22Al-2Cu alloy foams showed a typical lamellar eutectic microstructure, constituted by a zinc-rich phase (η) and a (α) solid solution that was richer in aluminum, while a copper-rich (ε) phase was formed in the interdendritic regions. The SEM micrographs show the presence of small particles and aggregates that are randomly scattered in the cell walls and correspond to unreacted calcite and Celestine–Barian particles, especially for the higher barite addition. The compressive curves showed smooth behavior, wherein the particles at the cell walls did not affect the foam’s compressive behavior. The trial containing 1.5 wt. % of BaSO₄ and 1.0 wt. % of CaCO₃ showed a higher energy absorption capacity of 5.64 MJ m⁻³ because of its highest relative density and lowest porosity values. The Celestine–Barian concentrate could be used as a foaming agent for high melt-point metals or alloys based on the TGA results. Full article

Since 2020, the REACh regulation requires toxicological data on nanoforms of materials, including the assessment of their skin-sensitizing properties. Small molecules’ skin sensitization potential can be assessed by new approach methodologies (NAMs) addressing three key events (KE: protein interaction, activation of dendritic cells, and activation of keratinocytes) combined in a defined approach (DA) described in the OECD guideline 497. In the present study, the applicability of three NAMs (DPRA, LuSens, and h-CLAT) to nine materials (eight inorganic nanomaterials (NM) consisting of CeO₂, BaSO₄, TiO₂ or SiO₂, and quartz) was evaluated. The NAMs were technically applicable to NM using a specific sample preparation (NANOGENOTOX dispersion protocol) and method modifications to reduce interaction of NM with the photometric and flowcytometric read-outs. The results of the three assays were combined according to the defined approach described in the OECD guideline No. 497; two of the inorganic NM were identified as skin sensitizers. However, data from animal studies (for ZnO, also human data) indicate no skin sensitization potential. The remaining seven test substances were assessed as “inconclusive” because all inorganic NM were outside the domain of the DPRA, and the achievable test concentrations were not sufficiently high according to the current test guidelines of all three NAMs. The use of these NAMs for (inorganic) NM and the relevance of the results in general are challenged in three ways: (i) NAMs need modification to be applicable to insoluble, inorganic matter; (ii) current test guidelines lack adequate concentration metrics and top concentrations achievable for NM; and (iii) NM may not cause skin sensitization by the same molecular and cellular key events as small organic molecules do; in fact, T-cell-mediated hypersensitivity may not be the most relevant reaction of the immune system to NM. We conclude that the NAMs adopted by OECD test guidelines are currently not a good fit for testing inorganic NM. Full article

In the present work, iron–sillenite (Bi₂₅FeO₄₀) was synthesized using a simple solid-state reaction method and characterized. The effects of the synthesis conditions on the phase purity of Bi₂O₃/Fe₃O₄, morphological features, and possible application as an XRD/MRI dual-contrast agent were investigated. For the synthesis, the stoichiometric amounts of Bi₂O₃ and Fe₃O₄ were mixed and subsequently milled in a planetary ball mill for 10 min with a speed of 300 rpm. The milled mixture was calcined at various temperatures (550 $°$C, 700 $°$C, 750 $°$C, 800 $°$C, and 850 $°$C) for 1 h in air at a heating rate of 5 °C/min. For phase identification, powder X-ray diffraction (XRD) analysis was performed and infrared (FTIR) spectra were recorded. The surface morphology of synthesized samples was studied by field-emission scanning electron microscopy (FE-SEM). For the radiopacity measurements, iron–sillenite specimens were synthesized at different temperatures and mixed with different amounts of BaSO₄ and Laponite solution. It was demonstrated that iron–sillenite Bi₂₅FeO₄₀ possessed sufficient radiopacity and could be a potential candidate to meet the requirements of its application as an XRD/MRI dual-contrast agent. Full article