Porous Form Research Articles

DETERMINATION OF OPTIMAL CONDITIONS FOR HERMETIC WELDING OF THIN FOILS WHEN USED IN MEMBRANE-TYPE STRUCTURES

Purpose. Development of optimal technology for welding thin-walled shells mode of 12Х18Н10Т steel (δ=0.15 mm), working at alternating loads. Research methods. Research methods. For welding automatic argon-arc welding (AAAW) equipment was used for of orbital welding, which includes a MW 2600 current source (FRONIUS) with software control unit and welding head of closed type MW40. Research warks showed that this type of welding is not enough for such small thicknesses concentration of the welding arc, which does not allow stable forming of the bath and obtaining solid uniform seam. A special robotic complex was used for microplasma welding STARWELD 190H, which includes: a power source for the regular arc INV 50; source main arc power supply INV 190; SIEMENS Simatic S 7-300 control unit; robot CR3-535M (MITSUBISHI); manipulator and HPH 80 plasmatron. Welding quality control was carried out by visual inspection and metallographic examination. Taking into account the conditions of operation of the parts, according to the technical conditions of the drawing, it was also provided pneumohydraulic control method. Obtained results. Visual inspection the outer surface of the welds showed the absence of defects in the form of pores, cracks, shells, no fusions, undercuts, etc. The geometric dimensions of the weld met the requirements of the standard documentation valid at the enterprise. Metallographic studies of the boxes membranes, welded by microplasma welding, gave a positive result. Defects of metallurgical character were not found in the welds. Practical value. The optimal method of welding that can be applied is determined for the manufacture of thin-walled membrane structures, from the point of view of manufacturability and economy expediency It has been established that microplasma welding allows obtaining a hermetically tight seam, when the thickness of parts to be welded is about 0.15 mm. The performance of welded membrane boxes is confirmed in the barostatic valve of an aircraft engine. It is established that micro plasma welding can be used in the manufacture of thin-walled shells made of 12X18H10T steel (δ=0.15 mm), which work at variable loads. The technological process of welding is introduced into the series production.

Microscopic Experiments to Assess the Macroscopic Sweep Characteristics of Carbon Dioxide Flooding

The Lunnan oilfield in the Tarim Basin, one of China’s major onshore oilfields with substantial geological reserves, faces particular challenges due to the complexity of its reservoir environment and the dispersion of remaining oil. Carbon dioxide, a greenhouse gas, presents an opportunity for enhanced oil recovery (EOR) and geological storage. In this context, the use of carbon dioxide for EOR can simultaneously address environmental concerns and improve oil recovery rates. This study focuses on the TI reservoir in the No. 2 well area of the Lunnan oilfield, employing advanced techniques to analyze the micro- and macro-characteristics of carbon dioxide flooding. Results: From the microscopic point of view, carbon dioxide flooding is mainly miscible with crude oil, which has a strong component exchange effect and can be displaced in the form of full pores, and the microscopic displacement efficiency is close to 100%. Macroscopically, under the combined injection and production of different injected hydrocarbon pore volume multiples (HCPVs), it is injected at the upper and lower layers of the interlayer and produced far away from the lower layer of the interlayer, with a total recovery rate of 52.83%. With the increase in the HCPV, the recovery increased rapidly at first and then slowly, and the HCPV at the demarcation point was 0.5, while the oil production rate increased in a wave-like manner and then decreased rapidly, and the HCPV at the breakthrough point of TI gas was 0.5. However, when the upper and lower layers far away from the interlayer are injected at the same time, the upper and lower layers of the interlayer are produced at the same time, and the total recovery rate can reach 83.02%. With the increase in the HCPV, the recovery rate increases rapidly at first and then slowly, and the HCPV at the turning point is 6.52. The oil production rate increases in a wave-like manner, then decreases rapidly, rises rapidly, and then decreases slowly in a wave-like manner. The HCPV at the breakthrough point of TI gas is 0.63, and the HCPV at the injection–production transition point is 0.63. The total recovery rate of carbon dioxide miscible displacement can reach 88.68% under the condition of separate injection and combined production with different injected hydrocarbon pore volume multiples. With the increase in the HCPV, the recovery increased rapidly at first and then slowly. The HCPV at the demarcation point was 6.5, the oil production rate increased in a wave-like manner, then decreased rapidly, increased rapidly, and then decreased slowly in a wave-like manner. The HCPV at the breakthrough point of TI gas was 0.63, and the HCPV at the injection–production transition point was 6.5. The research results provide data support for the physical reality of the microscopic and macroscopic sweep characteristics of carbon dioxide flooding in the Lunnan oilfield, Tarim Basin.

Construction of the technological process and design development of a multifunctional unit for processing vital soybeans with ultrasound. Feasibility of water-crude suspension

Cereals and legumes have a porous structure, being an inert carrier during mass exchange processes; they contain voids in the form of pores and stomata, on the surface of which there are foreign extractable substances in a solid state, in particular, trypsin and urease inhibitor proteins. These substances, due to their harmful effect on the final product, are subject to removal by extraction. One of the methods for inactivating anti-nutritional substances is ultrasonic treatment of soybeans.The article discusses the technology of inactivating inhibitors that worsen food and protein value of vital soybeans. The developed technology was aimed at dissolving a solid substance - soybean inhibitor protein in a liquid, carried out due to molecular diffusion, intensifying the processes of mass transfer and mass return. When creating a suspension by mixing the solid (crushed soybean grain) and liquid (water) phases, water molecules, which are a solvent, penetrate under the action of capillary forces into the pores and stomata of the treated body, begin to penetrate. On this basis, technological directions of research have been established, a sequence has been built and the physical essence of operations has been substantiated, consisting of four main ones - grinding soybean grain, creating a “water-soybean” suspension, ultrasonic (US) treatment of soybeans, drying. As a result of the conducted research, optimal technological parameters have been established for intensifying the process of inactivation of anti-nutritional substances contained in native soybeans: the degree of grinding of soybean grains is 0.5-1.0 mm; the ratio of water-soy suspension (1:1). The efficiency of the developed technological process will be factors affecting the quality of the resulting products, the duration and energy intensity of the process, resource conservation, simplicity of design and low cost of manufacture, the possibility of automation.

Lithofacies and diagenetic controls on thrombolitic dolomite reservoir development from the Precambrian Dengying Formation in the central Sichuan Basin, SW China

Microbialite reservoirs are of great importance in oil and gas exploration. However, there is still a lack of comprehensive studies on the formation mechanisms of thrombolitic reservoirs, a specific type of microbialite. This research focuses on the oldest thrombolitic dolomite reservoir located within the Precambrian Dengying Formation in the central Sichuan Basin, southwestern China. A multi-disciplinary approach was employed to characterize different thrombolite facies and elucidate the formation mechanism of thrombolitic dolomite reservoirs and their controlling factors, involving core observation, thin-section analysis, cathodoluminescence, scanning electron microscope (SEM) microscopy, elemental analysis using LA-ICP-MS, and carbon and oxygen stable isotope analysis. Based on variations in texture, four types of thrombolite were identified: 1) distinct clotted thrombolite, 2) diffuse and regular clotted thrombolite, 3) diffuse and irregular clotted thrombolite, and 4) composite clotted thrombolite. Notably, the diffuse clotted thrombolitic dolomite is the prevalent lithology in the reservoir. Through modification by meteoric water, organic acid fluids, and hydrothermal fluids, a reservoir with dominant porosity in the form of primary growth-framework pores, dissolution pores, and vugs was formed. This resulted in the development of two high-quality reservoir intervals within the Second Member and at the top of the Fourth Member of the Dengying Formation. The growth-framework porosity of the thrombolites, epigenetic karstification, and tectonic fracturing were mainly conducive to reservoir development. However, various types of cementation have reduced porosity and connectivity within the reservoir. Overall, this study is a valuable example of the methodology required to understand meso- and microstructures of deep-buried thrombolitic dolomite reservoirs, including their heterogeneities and diagenesis, as the original structures influence diagenesis.

Scale-span feature of surface analysis, macromolecular and pore structure in coal: Implications for inherent evolutionary mechanism of morphological microstructure

Morphological microstructural evolution of tectonic coal determines CBM storage and transportation mechanism as well as the occurrence of coal and gas outburst. Scale-span morphological feature of original and tectonic coals was characterized by AFM, Raman spectrum and physisorption method. The results demonstrate that metamorphism could remold the surface property of coal from rugged band to flat porous structure with pore form factor from 0.572 to 0.831, promoting the formation of regular and round pores. Tectonism facilitates ability of gas sorption in coal, breaking the basic structural integrity. Metamorphism could facilitate the ordered macromolecular structural evolution on recombination and aromatization as well as condensation; besides, tectonism may promote the evolution and development of microcrystalline structure in advance. The aforementioned results have revealed essential differences in morphological microstructure between original and tectonic coals, which are of great guiding significance to safe mining of CBM and prediction of coal and gas outburst.

Factors Controlling Differences in Morphology and Fractal Characteristics of Organic Pores of Longmaxi Shale in Southern Sichuan Basin, China

Shale gas is a prospective cleaner energy resource and the exploration and development of shale gas has made breakthroughs in many countries. Structure deformation is one of the main controlling factors of shale gas accumulation and enrichment in complex tectonic areas in southern China. In order to estimate the shale gas capacity of structurally deformed shale reservoirs, it is necessary to understand the systematic evolution of organic pores in the process of structural deformation. In particular, as the main storage space of high-over-mature marine shale reservoirs, the organic matter pore system directly affects the occurrence and migration of shale gas; however, there is a lack of systematic research on the fractal characteristics and deformation mechanism of organic pores under the background of different tectonic stresses. Therefore, to clarify the above issues, modular automated processing system (MAPS) scanning, low-pressure gas adsorption, quantitative evaluation of minerals by scanning (QEMSCAN), and focused ion beam scanning electron microscopy (FIB-SEM) were performed and interpreted with fractal and morphology analyses to investigate the deformation mechanisms and structure of organic pores from different tectonic units in Silurian Longmaxi shale. Results showed that in stress concentration areas such as around veins or high-angle fractures, the organic pore length-width ratio and the fractal dimension are higher, indicating that the pore is more obviously modified by stress. Under different tectonic backgrounds, the shale reservoir in Weiyuan suffered severe denudation and stronger tectonic compression during burial, which means that the organic pores are dominated by long strip pores and slit-shaped pores with high fractal dimension, while the pressure coefficient in Luzhou is high and the structural compression is weak, resulting in suborbicular pores and ink bottle pores with low fractal dimension. The porosity and permeability of different forms of organic pores are also obviously different; the connectivity of honeycomb pores with the smallest fractal dimension is the worst, that of suborbicular organic pores is medium, and that of long strip organic pores with the highest fractal dimension is the best. This study provides more mechanism discussion and case analysis for the microscopic heterogeneity of organic pores in shale reservoirs and also provides a new analysis perspective for the mechanism of shale gas productivity differences in different stress–strain environments.

Fabrication and Customization of Highly Porous PLGA Membranes Utilizing Near‐Field Electrospinning, Thermal Transitions, and Multilayer Strategies

Polymer porous membranes are crucial in various applications, including water filtration, tissue engineering, and drug administration. Conventional far‐field electrospinning (FFES) is widely used for producing polymeric membranes due to its cost‐effectiveness, scalability, and flexibility in using many polymers. However, FFES has limitations in controlling pore form and size, as it produces randomly oriented fibers that lead to inconsistent and noncustomizable pore sizes. To address these limitations, this work combines near‐field electrospinning (NFES) with thermal treatment of polymer fibers and membranes. NFES offers more precise control over fiber placement and alignment, producing well‐defined fiber patterns with consistent and customizable pore sizes without compromising the thickness of membranes. By exploring the interplay between polymer behavior, thermal effects, and capillary action, the differences in pore area under various temperatures and fiber spacings are characterized. Additionally, this study investigates the influence of multilayer infusion on pore size and geometric arrangement by examining multilayer configurations stacked at various angles. The results indicate that increasing the number of layers leads to decreased pore size, while the alignment of infused fibers affects pore shape. This integrated approach enhances control over membrane characteristics, improving the performance and consistency of polymer porous membrane fabrication across various applications.

Influence of Phthalic Acid on the Process of Dendrite Development in Low-Density Polyethylene During Electrical Breakdown

The presented work presents the results of a study on the effect of small amounts of phthalic acid additives on dendrite formation in low-density polyethene (LDPE). Based on the results obtained, it is shown that the dendrite resistance of LDPE, as expected, increases with the introduction of 0.05 wt% phthalic acid. The established increase in dendrite resistance of LDPE with the introduction of phthalic acid can primarily be explained based on a decrease in inhomogeneities in the form of air pores as a result of accelerated structure formation and the emergence of a more homogeneous supramolecular structure. It was revealed that an increase in dendrite resistance correlates with an improvement in the dielectric characteristics of the composition. The influence of mechanical load on the development of dendrites in polymer dielectrics has been studied. As a result of studying the growth of dendrites in LDPE samples and its optimal composition subjected to unilateral stretching, it was found that under the influence of mechanical tensile stresses, the shape of the surface delimiting tree-like shoots changes, this surface is flattened in the direction of stretching. It has been shown that the rate of dendrite growth increases as mechanical tensile forces increase.

An experimental process parameter study on the identification of defects in additively fabricated Al6061 with laser powder bed fusion

Additively fabricated metal parts using laser powder bed fusion (L-PBF) possess sophisticated morphology due to the recurrent use of laser-induced metal powder melting and solidification. The surface and 3D morphology of these parts often include defects in the form of protrusions, depressions, pores, voids, keyholes, or cracks that are known to be influenced by laser scanning paths and layer-to-layer processing. Such inconsistent part quality hampers the extensive adoption of L-PBF. Pores and cracks are detrimental to the fatigue life of the parts and components. Quantifying and controlling part defects and optimizing processing and scanning strategy parameters adaptively in real-time through in situ monitoring systems are highly desired. This study investigates the optimization of experimental process parameters (power, scan velocity, and hatch spacing) and their effects on the cracking and porosity of Al6061 alloy using machine learning techniques. Multi-objective optimization is formulated and conducted to determine the L-PBF parameters that minimize both porosity and crack densities.

Palmitoylation at a conserved cysteine residue facilitates gasdermin D-mediated pyroptosis and cytokine release

Gasdermin D (GSDMD)-mediated pyroptotic cell death drives inflammatory cytokine release and downstream immune responses upon inflammasome activation, which play important roles in host defense and inflammatory disorders. Upon activation by proteases, the GSDMD N-terminal domain (NTD) undergoes oligomerization and membrane translocation in the presence of lipids to assemble pores. Despite intensive studies, the molecular events underlying the transition of GSDMD from an autoinhibited soluble form to an oligomeric pore form inserted into the membrane remain incompletely understood. Previous work characterized S-palmitoylation for gasdermins from bacteria, fungi, invertebrates, as well as mammalian gasdermin E (GSDME). Here, we report that a conserved residue Cys191 in human GSDMD was S-palmitoylated, which promoted GSDMD-mediated pyroptosis and cytokine release. Mutation of Cys191 or treatment with palmitoyltransferase inhibitors cyano-myracrylamide (CMA) or 2-bromopalmitate (2BP) suppressed GSDMD palmitoylation, its localization to the membrane and dampened pyroptosis or IL-1β secretion. Furthermore, Gsdmd-dependent inflammatory responses were alleviated by inhibition of palmitoylation in vivo. By contrast, coexpression of GSDMD with palmitoyltransferases enhanced pyroptotic cell death, while introduction of exogenous palmitoylation sequences fully restored pyroptotic activities to the C191A mutant, suggesting that palmitoylation-mediated membrane localization may be distinct from other molecular events such as GSDMD conformational change during pore assembly. Collectively, our study suggests that S-palmitoylation may be a shared regulatory mechanism for GSDMD and other gasdermins, which points to potential avenues for therapeutically targeting S-palmitoylation of gasdermins in inflammatory disorders.

Studying the effect of the ratio of water to binder and sand to aggregate on the hardness of concrete mixtures and compressive strength of roller-compacted concrete by experimental method

In roller-compacted concrete technology, withthe use of low water and cement content, the concrete mixture after kneading has high hardness and compaction equipment must be used to compact and shape the product.Therefore, the content of mixing water, binder, and aggregate are considered decisive factors, greatly affecting the properties of roller compacted concrete in both the fresh state and the hardened state.The paper uses the mathematical method of two-factor rotatable central compositional planning to simulate the effect of volumetric ratios of water-binder (VN/VCKD) and sand-aggregate (VC/VCL) on the objective functions of the test. The selected objective functions are the hardness of the concrete mixture and the compressive strength of the roller-compacted concrete at the age of 28 days.From the obtained objective functions, it is shown that both control variables VN/VCKDand VC/VCLhave a significant influence on the valuesof the experimental model. When the VN/VCKDratio increases, the water content contributes to increasing the plasticityand reducing the hardness of the concrete mixture. At the same time, excess water exists in the concrete mass in the form of air bubbles,pores,and magnetism. That reduces the compressive strength of the product. Furthermore, the VC/VCLratio of the aggregate that is too small or too large tends to cause the compressive strength of the concrete to decrease.

Rear cortex contraction aids in nuclear transit during confined migration by increasing pressure in the cell posterior.

As cells migrate through biological tissues, they must frequently squeeze through micron-sized constrictions in the form of interstitial pores between extracellular matrix fibers and/or other cells. Although it is now well recognized that such confined migration is limited by the nucleus, which is the largest and stiffest organelle, it remains incompletely understood how cells apply sufficient force to move their nucleus through small constrictions. Here, we report a mechanism by which contraction of the cell rear cortex pushes the nucleus forward to mediate nuclear transit through constrictions. Laser ablation of the rear cortex reveals that pushing forces behind the nucleus are the result of increased intracellular pressure in the rear compartment of the cell. The pushing forces behind the nucleus depend on accumulation of actomyosin in the rear cortex and require Rho kinase (ROCK) activity. Collectively, our results suggest a mechanism by which cells generate elevated intracellular pressure in the posterior compartment to facilitate nuclear transit through three-dimensional (3D) constrictions. This mechanism might supplement or even substitute for other mechanisms supporting nuclear transit, ensuring robust cell migrations in confined 3D environments.

Texturally-enhanced 55S0P and 45S10P Bioactive Glass ceramic particles: Sol-gel fabrication, nano-characterization and comprehensive Bio-evaluation for applications in Bone tissue engineering

Bioactive glass ceramics (BGC) play a pivotal role in bone tissue engineering, specifically addressing challenges associated with bone repair and regeneration. In this study, we developed silica-based 55S0P and 45S10P spherical BGC nanoparticles (NPs), without and with P2O5 content, using a modified Stöber sol-gel process with base hydrolysis. The fabricated spherical NPs with pronounced textural features effectively contribute to enhanced surface roughness, a desirable parameter for improved biological activity in physiologically relevant solutions and tissue matrices. A comprehensive evaluation of the structural properties of these novel spherical BGC-NPs using diverse characterization techniques revealed distinct nano-textural features in the form of cracks and pores. The HR-TEM confirmed the nanoscale dimensions (170–190 nm) of particles with spherical surface morphology and also systematically analysed via DLS, FE-SEM studies. An augmented surface area with mesopores when phosphate added to the silica glass network was revealed by BET analysis. On the biological front, the study records the formation of an HCA layer on the surfaces of the BGC-NPs, the thickness of which increased with an increase in both phosphate content and immersion time (0, 3, 14 & 28 days) in the SBF solution. The zeta potential values attain a maximum from −22 mV to −23.6 mV for 55S0P and −21.5 mV to −26.4 mV for 45S10P BGC-NPs, and improved with increased immersion time, thereby favouring cellular adhesion for desired biological responses. In vitro, cell culture studies on MG-63 cells, after 24 and 72 h of incubation, demonstrated higher cell adhesion and proliferation, with pronounced biocompatibility. In addition, these BGC-NPs exhibited good hemocompatibility even at the highest test concentration (15 mg/ml) and demonstrated effective antibacterial activity against K. pneumoniae and E. coli. A combinatorial analysis of structural and biological properties revealed that the 45S10P BGC-NPs are more potent than 55S0P BGC-NPs for desired biological performances. In conclusion, the results suggest that the sol-gel fabricated BGC-NPs with enhanced nano-textural features are evidently suitable for applications in bone tissue engineering and regenerative medicine.

ELEMENTS OF TECHNOLOGY OF ELECTRON BEAM WELDING OF ALUMINUM ALLOYS FOR INSTALLATION AND REPAIR AND RESTORATION WORK ON THE SURFACE OF THE MOON

The exploration of the Moon cannot be carried out without the creationof long-term lunar bases (LB), as well as other objects that ensure the livelihoods and work of expeditions. These can be assembly and assembly operations during the creation of space complexes or repair and maintenance work related to ensuring the duration of operation of existing systems. Experiments on automatic welding in space, which were carried out on the “Vulkan” equipment, as well as welding with the manual electron beam tool «URI» in outer space, showed that electron beam welding (EBW) is the optimal technological process for performing welding work in space conditions. In this process, the effective efficiency is 85—90 %, which is the maximum compared to other welding methods. EBW in the conditions of terrestrial gravity allows us to ensure the mechanical and chemical properties of welded joints, as well as their density almost at the level of the base metal of the structure, which is impossible with other welding methods. Thus, the strength coefficient of the weld metal of welded joints from aluminum alloys obtained by EBW is 0.85...0.93, and with arc and plasma-arc methods, it is 0.7…0.8. At the same time, obtaining such properties of welded joints in space conditions is difficult. Of course, reduced gravity, low temperatures, and ultra-high vacuum, which are the natural environment on the lunar surface, contribute to the formation of internal leaks in the form of pores in welds (PW). This is primarily manifested in the welding of aluminum alloys, which are used as the main material in spacecraft structures.To obtain high-quality welded joints and exclude such defects as pores, cracks, and non-fusion of edges in the weld roots to be welded, a system of equipment for periodic deflection of the electron beam with a programmable heating intensity along a given trajectory was developed and manufactured. As a result of technological work carried out using a complex of equipment with a discrete deviation of the electron b eam, welded joints (WJ) were obtained from alloys AMg6, A1570, and 1201 with a thickness of 2 to 8 mm. The obtained PW was subject to visual inspection and X-ray control to determine external and internal defects in the WJ. Also, mechanical tests for the strength of resistance by tearing were carried out, the chemical composition was determined, and metallographic studies of PW obtained by the proposed method were performed. The results of the tests and studies showed the high quality of PP from aluminum alloys obtained by EBW using a discrete deflection of an electron beam with a programmable heating intensity along a given trajectory. The purpose of this work was to analyze the methods of degassing the molten metal of the weld pool, as well as the development and testing of the elements of the technological process of the EBW of aluminum alloys using the created equipment, which, when performing installation and repair and restoration work on the surface of the moon, will allow us to obtain high-quality WJ that meets the requirements for space designs.

Preparation of porosity-adjustable porous adsorbent materials derived from coal solid waste

Coal solid waste (CSW) was explored as precursor to prepare porous adsorption material (ACSW) by carbon dioxide activation. The effects of activation method (direct activation and pre-carbonization followed by activation), activation temperature, and activation time were systematically investigated. The burn-off characteristics of the CSW were measured, the ACSW were characterized by field emission scanning electron microscope, gas adsorption instrument and Raman spectrometer, and, in parallel, the adsorption ability was studied using methylene blue (MB) as a typical pollutant. The results showed that compared with direct activation, pre-carbonization reduced the carbon loss, increased the pore volume with pore size less than 1 nm, improved the carbon structural order and increased the MB adsorption performance. In addition, the evolution of the structure of the ACSW strongly depended on the activation temperature and time. With the increase of the activation time, the pore structure evolution underwent three stages: pore forming, expanding, and collapsing. Pore forming mainly involved clearing scattered graphite structures and amorphous carbon. Pore expanding mainly relies on consumption of regular graphite carbon crystal structure. At low temperature of 800 °C, micropores fully developed. As the activation temperature increased to 850–900 °C, pore expansion became apparent, mainly forming pores of 1–5 nm. Moreover, the MB adsorption capacity was positively correlated with the pore volume with pore size less than 5 nm. The burn-off can serve as an indicator for evaluating pore structure and the adsorption performance and when it was ∼25.5 %, the ACSW had the largest pore volume with pore size less than 5 nm and the highest MB adsorption capacity.

Harnessing Microbial Effectors for Macrophage-Mediated Drug Delivery.

Macrophage-based drug delivery systems are promising, but their development is still in its infancy, with many limitations remaining to be addressed. Our aim was to design a system harnessing microbial effectors to facilitate controlled drug cargo expulsion from macrophages to enable the use of more toxic drugs without adding to the risk of off-target detrimental effects. The pore forming and actin polymerizing Listeria monocytogenes effectors listeriolysin-O (LLO) and actin assembly-inducing protein (ActA) were synthesized using a novel green fluorescent protein (GFP)-linked heterologous expression system. These effectors were coated onto polystyrene beads to generate "synthetic cargo" before loading into primary M1 macrophages. Bead uptake and release from macrophages were evaluated by using high-throughput quantitative imaging flow cytometry and confocal microscopy. In vitro results confirmed appropriate activity of synthesized effectors. Coating of these effector proteins onto polystyrene beads (simulated drug cargo) resulted in changes in cellular morphology, bead content, and intracellular bead localization, which may support an interpretation of the induced release of these beads from the cells. This forms the basis for further investigation to fully elucidate any potential release mechanisms. Bacterial effectors ActA and LLO successfully effectuated actin polarization and protrusions from cell membranes similar to those seen in cells infected with Listeria spp., illustrating the potential of using these effectors and production methods for the development of an endogenous drug delivery system capable of low-risk, targeted release of high potency drugs.

Pore form and size dependence on plastic joining characteristics of resin/metallic foam by friction stir incremental forming

A metallic foam specimen was plastically joined with a resin (polymethyl methacrylate, PMMA) sheet by applying friction stir incremental forming (FSIF) process. In FSIF process, a rotating flat-ended (no probe) rod tool was pushed vertically and fed horizontally against the resin sheet which was placed on the foam. The tool operation heated frictionally the resin and deformed incrementally to the resin, while the tool operation did not deform plastically to the cellular matrix of the foam. Due to the plastic flow of the heated resin, the bottom of the resin was interlocked mechanically to the pores near the top surface of the foam. In this study, the relationship between the pore morphology (form and size) and the joining characteristics (joinability, flow thickness of the resin, and joining strength) was investigated using commercial open-cell nickel and closed-cell aluminum foams. According to the experimental investigations, the foam with small size and low depression angle of the surface pore showed better results in relation with the joining strength and the (flow thickness of the resin)/(depth of the surface pore).

A case study on the rotomolding behavior of black tea waste and bio-based high-density polyethylene composites: Do active compounds in the filler degrade during processing?

This study verified the possibility of using waste material from the food industry (black tea) as functional filler of rotomolded biobased high-density polyethylene-based composites. As part of the experimental work, the influence of the materials preparation, i.e., dry blending versus twin-screw extrusion, on the effectiveness of the stabilizing antioxidant effect of the black tea was analyzed. The aim of the work was to verify whether, despite the initial degradation of the structure of the lignocellulosic filler, it would be possible to keep its antioxidant capacity and the stabilizing effect on the polyethylene matrix. The research showed that the filler allowed to stabilize the polymeric matrix during the rotomolding process, despite the appearance of numerous defects in the form of pores and a reduction in mechanical properties, more significant for composites prepared by dry blending, obtaining elastic modulus drops of about 50 %. Furthermore, the pre-processing step by melt mixing results in a significant improvement of the composite's thermo-oxidation stability, with increases in the oxidation induction time (OIT), from 25 min for the HDPE to over 70 min for composites with 5 % black tea, and improved rheological behavior, preventing the crosslinking of the matrix, indicative of its thermo-oxidative degradation. The tea brewing process caused the decrease of antioxidant activity of the filler; however, it did not significantly affect the antioxidant behavior, maintaining its influence on the polymeric matrix when the material is prepared via twin-screw compounding, which was proved to provide better stability, increasing OIT by approximately 20 min later when compared to dry blending.

Investigation of granular natural stone materials as photothermal absorbers for sustainable and environmentally friendly energy harvesting

The development of cost-effective and environmentally friendly solar thermal technologies that deliver high performance poses several challenges, where the collector and absorber components play a pivotal role. This research addresses these issues by investigating enhanced temperature generation using a 30 cm × 30 cm Fresnel lens collector under solar illumination from a xenon lamp. Natural stone materials (andesite, coal, and pumice), characterized by granular structures with an average diameter of 1.68-2.00 mm, were selected because of their abundance and eco-friendliness. This research is focused on evaluating the effect of Fresnel lens on temperature generation performance. Two types of temperature generation tests were carried out: wet tests (where the natural stone materials were immersed in distilled water) and dry tests (where the natural stone materials were used in dry conditions). The morphologies of the natural stone materials were examined using an optical microscope and scanning electron microscope. Furthermore, the optical properties of the natural stone materials were analyzed using an ultraviolet-visible (UV-VIS) spectrophotometer. The findings revealed that there were significant improvements in the photothermal absorber performance with the use of a Fresnel lens in dry tests, where the highest temperature was achieved for coal (103.25 °C), followed by andesite (89.00 °C) and pumice (73.00 °C). The impurities varied between the materials, where the impurities were most dominant for pumice while coal was more uniform. Further examination using scanning electron microscope showed that all materials had light-trapping structures in the form of rough surfaces, pores, and crack gaps. Andesite was dominated by rough surfaces, while coal and pumice were dominated by crack gaps and pores, respectively. However, based on the UV-VIS spectrophotometric results, there were no correlations between the optical properties (absorbance, reflectance, and transmittance) and temperature achieved by the photothermal absorber materials. This research demonstrates the potential of using natural stone materials as photothermal absorbers in combination with a Fresnel lens collector for low-to-medium temperature solar thermal applications.

Influence of Early Freezing on the Pore Structure Characteristics of Concrete and Its Correlation with Mechanical Properties

Early freezing of concrete is common in the construction of water conservancy projects in northern China. Early freezing damage induces the deterioration of the mechanical properties of concrete structures, which seriously affects the safety, stability, and service life of engineering structures. Through a laboratory uniaxial compression test and a computed tomography (CT) test, the influence law of freezing time and freezing temperature on the mechanical properties of concrete is analyzed herein. The three-dimensional pore structure of concrete at different freezing times is reconstructed. The pore distribution and pore structure characteristic parameters of concrete at different freezing times are studied. The correlation between mechanical properties and the pore structure of early frozen concrete is determined. The results show that with the delay of freezing time, the porosity of concrete test blocks increases first and then decreases. The average pore surface area primarily decreases and then increases. The average pore diameter increases with the trend of a quadratic parabola. The average pore form factor primarily decreases, then increases, and then decreases. The average pore surface area has the best correlation with the compressive strength and elastic modulus of early frozen concrete. The outcomes suggest that the average pore surface area should be preferred when constructing the mesoscopic damage index of early frozen concrete. Relevant results provide support for revealing the macro and micro damage mechanisms of early frozen concrete.