MPa Pressure Research Articles

High-Pressure Processing Influences Antibiotic Resistance Gene Transfer in Listeria monocytogenes Isolated from Food and Processing Environments

The study aimed to assess the high-pressure processing (HPP) impact on antibiotic resistance gene transfer in L. monocytogenes from food and food processing environments, both in vitro (in microbiological medium) and in situ (in carrot juice), using the membrane filter method. Survival, recovery, and frequency of antibiotic resistance gene transfer analyses were performed by treating samples with HPP at different pressures (200 MPa and 400 MPa). The results showed that the higher pressure (400 MPa) had a significant effect on increasing the transfer frequency of genes such as fosX, encoding fosfomycin resistance, and tet_A1, tet_A3, tetC, responsible for tetracycline resistance, both in vitro and in situ. In contrast, the Lde gene (the gene encoding ciprofloxacin resistance) was not transferred under any conditions. In the food matrix (carrot juice), greater variability in results was observed, suggesting that food matrices may have a protective effect on bacteria and modify HPP efficacy. In general, an increase in MIC values for antibiotics was noted in transconjugants compared to donors. Genotypic analysis of transconjugants showed differences in genetic structure, especially after exposure to 400 MPa pressure, indicating genotypic changes induced by pressure stress. The study confirms the possibility of antibiotic resistance genes transfer in the food environment, even from strains showing initial susceptibility to antibiotics carrying so-called silent antibiotic resistance genes, highlighting the public health risk of the potential spread of antibiotic-resistant strains through the food chain. The findings suggest that high-pressure processing can increase and decrease the frequency of resistance gene transfer depending on the strain, antibiotic combination, and processing conditions.

Improved CO2 capture capacity of waste sawmill dust derived activated carbon employing novel high-pressure CO2 activation

The porosity of activated carbon is significantly influenced by both the precursor biomass and the activation parameters. Waste sawmill wood (WSW) dust, an abundantly available precursor from the furniture manufacturing, construction, carpentry, and shipbuilding industries, was collected, dried, pulverized, carbonized, and activated using steam and a novel high-pressure CO2 activation approach. Activation was performed in a tubular furnace at 800 °C with a pure CO2 flow for 90 min at 1 MPa pressure (WSW-A800-CO2-90 min-1 MPa). Another activated carbon sample was synthesized from the same precursor at atmospheric pressure using steam flow at 700 °C for 20 min (WSW-A700-Steam-20 min). XRD and FTIR analyses were conducted to compare the structural information of both samples. Additionally, the thermal characteristics of the samples were determined by measuring their specific heat capacities. N2 and CO2 adsorption experiments were performed to investigate the porous properties and CO2 capture capacities of the synthesized samples. The activated carbon synthesized in a pressurized CO2 environment produced a BET surface area of 684 m2/g, while steam activation achieved a BET surface area of 947 m2/g. Interestingly, despite the lower surface area of the CO2-activated sample, it exhibited a higher CO2 adsorption capacity (106.29 mg/g at 5 °C and 110 kPa) compared to the steam-activated carbon due to its unique pore size distribution. The experimental CO2 adsorption data were also correlated with Langmuir, Freundlich, and modified Dubinin-Astakhov (D-A) models to elucidate the CO2 capture parameters, such as isosteric heat of adsorption, activation energy, and Gibbs free energy.

Exploring of laccase-like nanozyme and membrane filters for efficient removal of tetracycline hydrochloride

Laccase is utilized as green catalyst in the environmental catalysis. Nevertheless, the drawbacks such as poor stability and difficulty in recycling have seriously restricted its application. Here, we simulated the binding pocket and catalytic active site of nature laccase, and designed a laccase-mimicking nanozyme (named as GA-Cu and the average diameter was 600 nm) with high activity and stability by using Cu2+ as the active center, 2-aminoimidazole as well as glutathione (GSH) as the ligand. Compared with natural laccase, the GA-Cu nanozymes showed excellent stability and reusability under extreme conditions. Furthermore, to overcome the problems of difficult recycling and easy secondary contamination, we innovatively proposed to load GA-Cu nanozymes onto nylon membranes (GA-Cu@CS/GA-Cu/nylon membranes) by vacuum-assisted filtration using chitosan (CS) as a binder to degrade tetracycline hydrochloride (TC) by filtration. Encouragingly, 50 mg/L of TC was almost completely removed by filtration once at 0.15 MPa pressure. The results have showed that the GA-Cu@CS/GA-Cu/nylon membrane removed TC mainly through degradation, and more than 80 % of TC was degraded through desorption experiments. Finally, some degradation products were identified by LC-MS and three possible degradation pathways were proposed. These findings demonstrate the potential of GA-Cu@CS/GA-Cu/nylon membrane for environmental remediation, and will be a general and important strategy for the design of membrane filters based on the excellent performance of nanozyme.

Properties of multiple rare earth oxides co-stabilized YDyGdSmNd-TZP ceramics

TZP starting powders containing 0.6 mol% each of yttria, dysprosia, gadolinia, samaria and neodymia stabilizer were fabricated by a wet chemical route by coating monoclinic zirconia with rare earth nitrates and subsequent calcination. The powders were consolidated by hot pressing in the temperature range between 1250 °C–1500 °C for 1 h at 60 MPa pressure. The materials were characterized with respect to microstructure, phase composition and mechanical properties. The materials combine high fracture toughness over the whole sintering temperature range with moderate hardness and attractive strength. XRD showed that a redistribution of stabilizers takes place during sintering, an initial highly tetragonal phase containing little or no stabilizer is successively eliminated and a stabilizer saturated tetragonal phase is progressively formed. The volume fraction of cubic increases with sintering temperature as the stabilizer content increases. Above 1500 °C, a plate-shaped aluminate phase is formed from the alumina sintering aid and rare earth oxide.

The Gasification and Pyrolysis of Biomass Using a Plasma System

This research paper analyzes the use of plasma technology to process biomass in the form of dried, mixed animal manure (dung containing 30% moisture). The irrational use of manure as well as huge quantities of it can negatively impact the environment. In comparison to biomass fermentation, the plasma processing of manure can greatly enhance the production of fuel gas, primarily synthesis gas (CO + H2). The organic part of dung, including the moisture, is represented by carbon, hydrogen, and oxygen with a total concentration of 95.21%, while the mineral part is only 4.79%. A numerical analysis of dung plasma gasification and pyrolysis was conducted using the thermodynamic code TERRA. For 300–3000 K and 0.1 MPa pressure, the dung gasification and pyrolysis were calculated with 100% dung + 25% air and 100% dung + 25% nitrogen, respectively. Calculations were performed to determine the specific energy consumption of the process, the composition of the products of gasification, and the extent of the carbon gasification. At 1500 K, the dung gasification and pyrolysis consumed 1.28 and 1.33 kWh/kg of specific energy, respectively. A direct-current plasma torch with a power rating of 70 kW and a plasma reactor with a dung processing capacity of 50 kg/h were used for the dung processing experiments. The plasma reactor consumed 1.5 and 1.4 kWh/kg when pyrolyzing and gasifying the dung. A maximum temperature of 1887 K was reached in the reactor. The plasma pyrolysis of dung and the plasma–air gasification of dung produced gases with specific heats of combustion of 10,500 and 10,340 kJ/kg, respectively. Calculations and experiments on dung plasma processing showed satisfactory agreement. In this research, exergy analysis was used to quantify the efficiency of the plasma gasification of biomass. One of the research tasks was to develop a methodology and establish standards for the further standardization of monitoring the toxic emissions of dioxins, furans, and Benzo[a]pyrene.

The influence mechanism of mechanical modification on fly ash carbonation to solidify heavy metals

Dry and wet milling, were selected to carry out modification experiments. The influence of mechanical modification pretreatment on fly ash carbonation to solidify heavy metals was explored, and its influence mechanism was revealed. Mechanical modification can improve the physical properties, and the continuous application of mechanical energy can activate the active sites which strengthen fly ash carbonation. The carbonation efficiency was obtained by 500–800 °C thermogravimetric analysis before and after carbonation. The average carbonation efficiency improved by dry milling is 2.28 %, and that improved by wet milling is 8.11 %. Carbonation has a good curing effect on Cr, Cd, Pb and As, especially when the CO2 is raised to supercritical. At 8 MPa pressure, the leaching concentrations of Cr, Cd, Pb and As decrease by 34.94 %, 7.00 %, 15.28 % and 35.85 %. The stabilization effect of fly ash carbonation on heavy metals is significantly improved after mechanical modification pretreatment. Comparison experiments on characterization of fly ash before and after mechanical modification shows that ball milling significantly increases the specific surface area. The crushing effect of wet milling is better, because the presence of water weakens the agglomeration of fine particles caused by van der Waal force. Mechanical modification can effectively improve the pore structure of fly ash and activate active sites which promote carbonation to form a larger physical wrapping area and strengthen stable carbonate formation. so mechanical modification effectively improves the solidification of heavy metals by carbonation.

Combined effect of compressing fresh concrete and curing regime on bonding performance of high strength repair mortar

High strength concrete (HSC) is highly appropriate for the retrofitting and rehabilitation of reinforced concrete structures due to its low permeability and high bonding strength. However, its low workability and sensitivity to curing conditions pose significant challenges for its implementation in such projects. This study introduces a novel technique to overcome the workability barrier of HSC while enhancing its bonding strength under various curing conditions. To achieve this, four different pressures (0, 0.87, 2.61, and 5.23 MPa) were applied to fresh high strength repair mortar (HSRM) and HSC for durations of 2, 4, and 8 h. Subsequently, different curing methods, including the wet sack method, steam curing method, and the use of curing compounds, were employed. The modulus of elasticity and compressive strength of HSC, in addition to bonding performance between substrate HSC and 28-day compressed HSRM, were evaluated using the “friction-transfer” and “twist-off” techniques, which are standard techniques for measuring the bonding strength of concrete both in the laboratory and in-situ. Also, to further assess the effect of curing regime and pressure on the microstructures of HSRM, SEM images of 28-day HSRM specimens were collected. The results indicated that increasing the pressure to 5.23 MPa and extending the duration to 8 h enhanced the ultimate torsional shear strength between HSRM and substrate HSC by an average of 174%. Additionally, the mechanical properties of HSC were considerably enhanced by applying 5.23 MPa pressure over 8 h. It is worth mentioning that the bonding strength between HSRM and substrate HSC without curing was highly affected by the duration of pressure application compared to the three investigated curing methods. The wet sack curing method was found to be the most effective for enhancing the degree of hydration and increasing the failure torsional shear stress of compressed HSRM specimens.

Simulation and Mechanistic Exploration of the Mid to Late-Stage Hydrothermal Carbonization Process in Biomass

Using C143H108O4 as the model for hydrochar, unsaturated small molecules necessary for polymerization reactions were added to extend the simulation of the hydrothermal carbonization (HTC) growth process. This enabled a comprehensive exploration of the pressure (density), small-molecule structure, water influence conditions, and related HTC reaction mechanisms in the middle to late stages of the process. The simulation results indicate that in a high-pressure system with a simulated pressure of 200MPa, there is a greater quantity of hydrochar formation when compared to systems at lower pressures. The addition of unsaturated small molecules, such as CH2O2, C4H5O, C4H6, C3H4, and C4H5 reduces the need for intermolecular dehydrogenation or hydrogen transfer reactions in the system, indirectly accelerating subsequent HTC reactions. In particular, the addition of H2O was detrimental to mid to late-stage HTC reactions, which are primarily dominated by both polymerization and aromatization reactions, as the addition was found to significantly increase the level of free H in the system. Consequently, compared with the absence of water, this results in the formation of a relatively hydrogen-rich environment in the molecular system, contrary to the requirements of mid to late-stage HTC reactions. Additionally, a recurring observation in mid to late-stage HTC reactions is the continuous occurrence and repetition of “polymerization-decomposition-polymerization” processes among large fragment molecules, representing a transition from unstable to relatively stable structures. Aromatization between fragments is crucial for transition to stable structures. Finally, in conjunction with wavefunction analysis of the polymer, it was observed that the aromatic polymer interactions gradually exerted a significant influence on the molecular structure as the temperature decreased to room temperature at 300K. This resulted in the gradual clustering of molecular structures, potentially contributing to the spherical and core-shell structures of the hydrochar microparticles.

Kinetics of CO2 hydrate formation in clayey sand sediments: Implications for CO2 sequestration

Hydrate-based CO2 sequestration beneath oceanic sediments is an emerging technique that involves the injection of CO2 into the hydrate stability zone (HSZ) beneath the seabed, forming hydrate cap that structurally traps the injected CO2 and reduces the risk of leaking CO2 from the storage sediment. Gas hydrates are adequately stable in sand sediments saturated with fresh water; however, the salinity of oceanic water impairs hydrate formation kinetics, stability, and CO2 storage capacity. In addition to sandstones, marine sediments are composed of many clay minerals that could affect hydrate formation. Therefore, this study experimentally simulates CO2 injection into sand and clayey sand sediments to assess the potential of CO2 hydrate formation. CO2 hydrates are formed inside a high-pressure reactor, which contains unconsolidated sediment bed/pack (silica sand; mixed sand with bentonite clay: 5 wt% and 10 wt%), saturated with de-ionized water or brine (3.3 wt% NaCl). Hydrate formation experiments were performed at 4 MPa pressure and 274.15 K temperature. Results show that CO2 hydrate formed within the sand sediment, with induction times of 6 and 8.5 h, for the de-ionized and brine systems, respectively. CO2 gas mole uptake in the de-ionized system was 71.54 mmol/mol however, in the brine system the gas uptake was 56.95 mmol/mol. Hence this 20.4% reduction in the gas uptake indicated the inhibition effect of salinity. In contrast, in the brine-saturated 5 wt% clay-sand sediment, the induction time was 6.5 h, indicating the promoting effect of the nano-sized clay particles. However, the gas uptake in this brine-saturated clay-sand sediment was reduced by 45.51% compared to the brine-saturated sand sediment. Increasing the clay content to 10 wt% prevented CO2 hydrate formation due to porosity reduction. Moreover, de-ionized water in clayey sand sediments prevented hydrate formation due to clay swelling. Finally, CO2 hydrate formation at the end of each experiment was visually confirmed.

Pressure-induced formability and degradability of block copolymers composed of poly(1,5-dioxepan-2-one) and poly(L-lactide)

An aliphatic polyether/carbonate block copolymer, comprising poly(1,5-dioxepan-2-one) (PDXO, glass transition temperature Tg: -38 °C) and poly(L-lactide) (PLLA, Tg: 55 °C), evinces remarkable formability under pressure at temperatures significantly below the melting point of PLLA. A quantitative and detailed evaluation of the low-temperature molding of the block copolymer was conducted using a capillary rheometer. The findings reveal that block copolymers with PDXO composition >55 wt% demonstrate a propensity to flow at room temperature under 50 MPa pressure. Consequently, the practice of low-temperature molding serves to mitigate the degradation of polymer chains during the molding process, thereby augmenting recyclability. Furthermore, the enzymatic degradability of the block copolymer was extensively investigated using lipase PS and proteinase K. An interplay between the structure of the block copolymer and the degradation kinetics was explored. The polymeric materials developed, possessing both pressure formability and degradability, hold promising potential as environmentally benign polymers with reduced environmental impact.

Investigation on Water Erosion Behavior of Ti-based Metal Matrix Composite: Experimental Approach

Wet steam flow produces big water droplets in the low-pressure zone of a steam turbine blade. These droplets clash with subsequent blades, resulting in a strong impact that is evident as erosion. Titanium and its alloys are valuable for technical applications such as turbine blades because of their low density, high strength, and exceptional corrosion resistance. The boron carbide(B4C) has a high hardness but a low strength; therefore, it's exciting to investigate water erosion of Ti/ B4C and SiC combination. The effect of 1 wt% B4C and 1, 3, 5, and 7 wt% SiC particles on water droplet erosion of Ti composite was studied using the SPS method for 5 minutes at 1200 oC temperature and 50 MPa pressure. The L9 orthogonal array with four levels of parameters of the Taguchi method is used to conduct the experiments. By measuring the weight of the specimen at interval time, the erosion behavior with time is obtained with different nozzle diameters. The effect of material and experimental parameters on erosion resistance is studied, and an empirical relation is developed.

Rheological behavior of deep eutectic solvent promoted methane hydrate formation

Natural gas hydrates are recognized as a crucial and sustainable energy resource. The formation, dissociation, and flow properties of CH4 hydrate from deep eutectic solvents (DESs) are investigated using a high-pressure rheometer. In this work, rheological experiments are performed using two DESs namely, tetrabutylammonium bromide + ethylene Glycol (TBAB + EG, DES1) and methyltriphenylphosphonium bromide + ethylene Glycol (MTPB + EG, DES2) at 1 wt% concentration, 274 K temperature and 8 MPa pressure. The hydrate formation starts around 1.7 h for DES1 and around 4 h for DES2. Pressure and viscosity of the slurry are analyzed while methane hydrate forms and dissociates. The pressure drop experienced during hydrate formation is roughly 1.4 MPa for DES1 and 1.7 MPa for DES2. Further, viscosity profiles are analyzed for both DESs with varying shear rate. The viscosity gradually decreases as the shear rate increases. At equilibrium conditions of pure CH4, a spike is observed during dissociation. The rheological data is further analyzed with Cross model to validate the shear-thinning behavior of methane hydrate.

Low-temperature Cu-Cu direct bonding with ultra-large grains using highly (110)-oriented nanotwinned copper

With the application of Cu-Cu direct bonding technology in high-performance electronic devices, improving bonding reliability is essential for achieving high-density 3D IC integration. In this study, we innovatively applied highly (110)-oriented perpendicular nanotwinned Cu (p-ntCu) to achieve Cu-Cu direct bonding at low temperature and pressure. The anisotropic growth of p-ntCu during annealing at 200 °C resulted in the formation of ultra-large grains, which could improve the conductivity of the electrodeposited Cu film. Two Cu films were bonded at 200–250 °C with 2 MPa pressure for 1 h, and there was almost no void at the bonding interface. Anisotropic grain growth occurred within the bonding joint and grain boundary migration was observed at the bonding interface. The shear strength after bonding at 250 °C was measured as 58.3 MPa on average, indicating a relatively high quality of such Cu-Cu bonding. The p-ntCu can achieve Cu-Cu bonding and improve the conductivity by anisotropic grain growth at low temperature and pressure, which has great potential for Cu interconnect applications.

The Role of Ligand Exchange in Salen Cobalt Complexes in the Alternating Copolymerization of Propylene Oxide and Carbon Dioxide.

A comparative study of the copolymerization of racemic propylene oxide (PO) with CO2 catalyzed by racemic (salcy)CoX (salcy = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-diaminocyclohexane; X = perfluorobenzoate (OBzF5) or 2,4-dinitrophenoxy (DNP)) in the presence of a [PPN]Cl ([PPN] = bis(triphenylphosphine)iminium) cocatalyst is performed in bulk at 21 °C and a 2.5 MPa pressure of CO2. The increase in the nucleophilicity of an attacking anion results in the increase in the copolymerization rate. Racemic (salcy)CoX provides a high selectivity of the copolymerization, which can be higher than 99%, and the living polymerization mechanism. Poly(propylene carbonate) (PPC) with bimodal molecular weight distribution (MWD) is formed throughout copolymerization. Both modes are living and are characterized by low dispersity, while their contribution to MWD depends on the nature of the attacking anion. The racemic (salcy)CoDNP/[PPN]DNP system is found to be preferable for the production of PPC with a high yield and selectivity.

Model for atomization droplet size and energy distribution ratio at the distal end of an electrostatic nozzle

Electrostatic atomization minimum quantity lubrication (EMQL) employs the synergistic effect of multiple physical fields to atomize minute quantities of lubricant. This innovative methodology is distinguished by its capacity to ameliorate the atomization attributes of the lubricant substantially, which subsequently augments the migratory and infiltration proficiency of the droplets within the complex and demanding milieu of the cutting zone. Compared with the traditional minimum quantity lubrication (MQL), the EMQL process is further complicated by the multiphysical field influences. The presence of multiple physical fields not only increases the complexity of the forces acting on the liquid film but also induces changes in the physical properties of the lubricant itself, thus making the analysis of atomization characteristics and energy distribution particularly challenging. To address this objective reality, the current study has conducted a meticulous measurement of the volume average diameter, size distribution span, and the percentage concentration of inhalable particles of the charged droplets at various intercept positions of the EMQL nozzle. A predictive model for the volume-averaged droplet size at the far end of the EMQL nozzle was established with the observed statistical value F of 825.2125, which indicates a high regression accuracy of the model. Furthermore, based on the changes in the potential energy of surface tension, the loss of kinetic energy of gas, and the electric field work at different nozzle orifice positions in the EMQL system, an energy distribution ratio model for EMQL was developed. The energy distribution ratio coefficients under operating conditions of 0.1 MPa air pressure and 0 to 40 kV voltage on the 20 mm cross-section ranged from 3.094‰ to 3.458‰, while all other operating conditions and cross-sections had energy distribution ratios below 2.06‰. This research is expected to act as a catalyst for the progression of EMQL by stimulating innovation in the sphere of precision manufacturing, providing theoretical foundations, and offering practical guidance for the further development of EMQL technology.

Experimental study on the rock breaking effect of different tooth shapes of inserted teeth in a hobbing-cone hybrid PDC bit under complex stress environment

The hobbing-cone hybrid PDC bit has emerged with the increasing exploitation of deep oil and gas resources. As an important component of new bits, studying the mechanism of toothed fracturing of deep rocks is crucial for improving rock-breaking efficiency. In this paper, the spherical teeth and conical teeth were used to intrude sandstone under different confining pressures, and the brittleness index (BIm), specific energy (SE), and average fragment size (dm) were used to analyze the rock-breaking effect. The 3D contour scanner quantitatively analyzed the crushing pit area. Finally, the in-situ CT scanning and discrete element numerical simulation were used to summarize the crack propagation law. The results show that with the increase of confining pressure, the BIm of inserted teeth increases continuously, and the growth rate of conical teeth increases, while that of spherical teeth decreases. The SE and dm exhibit a symmetrical distribution with a confining pressure of 10MPa as the axis of symmetry. When the difference in principal stress is 5MPa, the SE is the lowest point, the rock-breaking efficiency is the highest, and the corresponding dm is at the highest point, but the curve trend is the opposite. When the stress difference is 5MPa, it is conducive to propagating surface cracks, thus forming a larger crushing area and the highest rock-breaking efficiency. Based on CT results, the dense particle core is formed near the inserted teeth, and that of the spherical teeth is located below. In contrast, that of the conical teeth is located on the side, which is also the reason for the difference in crack propagation between different tooth shapes.

From Darcy to turbulent flow: Investigating flow characteristics and regime transitions in porous media

This research addresses the flow characteristics within a porous medium composed of a monolayer of closely packed spheres, spanning from viscous-dominated to turbulent flow regimes. In the first part of this paper, the turbulent flow characteristics at a 30 MPa pressure drop within the domain are presented. The results are averaged across different cross sections between the inlet and outlet. In the second part of the study, simulations are conducted with pressure drops, ranging from nearly 0 to 100 MPa. The analysis finds distinct flow patterns within the domain and provides estimations for the permeability and the inertial term coefficient. Moreover, the transition from Darcy to non-Darcy and turbulent flow is achieved through the use of different criteria. The specified geometry is suitable for validating and calibrating simplified discrete element method models coupled with computational fluid dynamics. The main goal of this research is to produce a reliable benchmark to figure out the challenge of limited experimental data concerning fluid flow characteristics in densely packed granules specially subjected to high pressure conditions. To do this, representative specimens are designed, accurate simulations are conducted, and precise assessments of the results are carried out.

A comprehensive numerical procedure for high-intensity focused ultrasound ablation of breast tumour on an anatomically realistic breast phantom.

High-Intensity Focused Ultrasound (HIFU) as a promising and impactful modality for breast tumor ablation, entails the precise focalization of high-intensity ultrasonic waves onto the tumor site, culminating in the generation of extreme heat, thus ablation of malignant tissues. In this paper, a comprehensive three-dimensional (3D) Finite Element Method (FEM)-based numerical procedure is introduced, which provides exceptional capacity for simulating the intricate multiphysics phenomena associated with HIFU. Furthermore, the application of numerical procedures to an anatomically realistic breast phantom (ARBP) has not been explored before. The integrity of the present numerical procedure has been established through rigorous validation, incorporating comparative assessments with previous two-dimensional (2D) simulations and empirical data. For ARBP ablation, the administration of a 0.1 MPa pressure input pulse at a frequency of 1.5 MHz, sustained at the focal point for 10 seconds, manifests an ensuing temperature elevation to 80°C. It is noteworthy that, in contrast, the prior 2D simulation using a 2D phantom geometry reached just 72°C temperature under the identical treatment regimen, underscoring the insufficiency of 2D models, ascribed to their inherent limitations in spatially representing acoustic energy, which compromises their overall effectiveness. To underscore the versatility of this numerical platform, a simulation of a more clinically relevant HIFU therapy procedure has been conducted. This scenario involves the repositioning of the ultrasound focal point to three separate lesions, each spaced at 3 mm intervals, with ultrasound exposure durations of 6 seconds each and a 5-second interval for movement between focal points. This approach resulted in a more uniform high-temperature distribution at different areas of the tumour, leading to the ablation of almost all parts of the tumour, including its verges. In the end, the effects of different abnormal tissue shapes are investigated briefly as well. For solid mass tumors, 67.67% was successfully ablated with one lesion, while rim-enhancing tumors showed only 34.48% ablation and non-mass enhancement tumors exhibited 20.32% ablation, underscoring the need for multiple lesions and tailored treatment plans for more complex cases.

Preparation and Electrothermal Transport Behavior of Sn8[(Ga2Te3)34(SnTe)66]92 Bulk Glass.

High-conductivity tellurium-based glasses were anticipated to be the attractive candidates in chalcogenide glass systems on account of their distinctive characteristics and extensive application prospects. In this paper, the high-density (>96%) Sn8[(Ga2Te3)34(SnTe)66]92 bulk glass with the density of 5.5917 g/cm3 was successfully prepared by spark plasma sintering (SPS) technology at 460 K, using a 5 min dwell time and 450 MPa pressure. The room-temperature thermal conductivity of Sn8 bulk materials significantly decreased from 1.476 W m-1∙K-1 in the crystalline sample to 0.179 W m-1∙K-1 in the glass, and the Seebeck coefficient obviously increased from 35 μV∙K-1 in to 286 μV∙K-1, indicating that the glass transition of tellurium-based semiconductors could optimize the thermal conductivity and Seebeck coefficient of the materials. Compared to the conventional tellurium-based glassy systems, the fabricated Sn8 bulk glass presented a high room-temperature conductivity (σ = 6.2 S∙m-1) and a large glass transition temperature (Tg = 488 K), which was expected to be a promising thermoelectric material.

In-Situ Coating of Iron with a Conducting Polymer, Polypyrrole, as a Promise for Corrosion Protection

Iron microparticles were coated with polypyrrole in situ during the chemical oxidation of pyrrole with ammonium peroxydisulfate in aqueous medium. A series of hybrid organic/inorganic core–shell materials were prepared with 30–76 wt% iron content. Polypyrrole coating was revealed by scanning electron microscopy, and its molecular structure and completeness were proved by FTIR and Raman spectroscopies. The composites of polypyrrole/carbonyl iron were obtained as powders and characterized with respect to their electrical properties. Their resistivity was monitored by the four-point van der Pauw method under 0.01–10 MPa pressure. In an apparent paradox, the resistivity of composites increased from the units Ω cm for neat polypyrrole to thousands Ω cm for the highest iron content despite the high conductivity of iron. This means that composite conductivity is controlled by the electrical properties of the polypyrrole matrix. The change of sample size during the compression was also recorded and provides a parameter reflecting the mechanical properties of composites. In addition to conductivity, the composites displayed magnetic properties afforded by the presence of iron. The study also illustrates the feasibility of the polypyrrole coating on macroscopic objects, demonstrated by an iron nail, and offers potential application in the corrosion protection of iron. The differences in the morphology of micro- and macroscopic polypyrrole objects are described.