Search Results (99)

3D-printing enables the fabrication of membranes with desired shapes and geometrical parameters. In this study, a membrane for pressure-driven processes was manufactured in a single step using the fused deposition modeling (FDM) technique. The membrane was produced from a mixture of polylactic acid (PLA) with sucrose as a pore-forming agent. Sucrose was removed from the final membrane by washing it with water. The membrane consists of three layers, and this sandwich-like structure ensures its mechanical stability. The material obtained was characterized using SEM and AFM imaging, as well as nitrogen adsorption-desorption and contact angle measurements. The porosity of each layer of the membrane is due to a loose region, which is coated on both sides with a dense film formed during printing. The pores responsible for rejection capability can be found in grooves between the polymer stripes in the dense layer. The membrane exhibits a water permeability of 64 L m⁻²h⁻¹bar⁻¹, with a molecular weight cut-off of 69 kDa. The PLA membrane can be used for polyphenol concentration, demonstrating a permeability of 2–3.4 L m⁻²h⁻¹bar⁻¹ and a selectivity towards these compounds of 78–98% at 0.5 bar, with a flux decline ratio of up to 50%. Full article

A new method for measuring internal pore water pressure (PWP) is introduced to determine the critical state line (CSL) in partially frozen sand, investigating the influence of temperature and strain rate on the critical state parameters. A series of consolidated undrained and drained triaxial tests, along with internal PWP measurements, were conducted on both dense and loose specimens under different temperatures and strain rates. Similarly to unfrozen sand, a unique CSL was established for the partially frozen sand at −3 °C in both stress ($q$-$p^{\prime }$) and void ratio $(e$-$p^{\prime })$ space. The results show that the critical state friction angle (${\phi }_{cs}^{\prime }$) is not affected by temperature (warmer than −5 °C) and strain rate, while the critical state cohesion ($c_{cs}^{\prime }$) varies with temperature, strain rate and failure mode. The $c_{cs}^{\prime }$ increases with decreasing temperature from 23 °C to −3 °C and to −10 °C, but decreases to zero when the strain rate was reduced from 1%/min to 0.1%/min. In $e$-$p^{\prime }$ space, the slope of CSL could be associated with the dilation of partially frozen sand, which increases with decreasing temperature and increasing strain rate, potentially due to the increased contact area between the pore ice and sand grains. Full article

The adhesion between dibenzofuran (DF) and degrading bacteria is the first step of DF biodegradation and affects the efficient degradation of DF. However, their efficient adhesion mechanism at the molecular level remains unclear. Therefore, this study first examined the adhesive behaviors and molecular mechanisms of Rhodococcus sp. strain p52 upon exposure to DF. The results showed that the adhesion between strain p52 and DF is mediated by extracellular polymeric substances (EPSs). Compared with sodium acetate as a carbon source, the percentages of glucose and proteins related to electron transfer, toxin–antitoxin, and stress responses were elevated, which were analyzed by polysaccharide composition and proteomics, and the contents of extracellular polysaccharides and proteins were increased. Moreover, biofilm analysis suggested an increase in EPS content, and the change in components increased biofilm yield and promoted loose and porous aggregation between the bacteria; this aggregation caused an increase in the specific surface area in contact with DF. The surface characteristics analysis indicated that the production of EPS reduced the absolute value of the zeta potential and increased the hydrophobicity of strain p52, which was beneficial for the adhesion of strain p52 and DF. These findings help us to enhance the understanding of the adhesion mechanisms and bioremediation of polycyclic aromatic hydrocarbons by degrading bacteria. Full article

Pickering emulsions (PEs) of natural plant proteins enriched in fat-soluble components are gaining consumer interest for healthier and sustainable products. The aim of this study is to prepare PEs for stabilizing almond protein isolated (API) particles loaded with astaxanthin using ultrasound technology. The loose structure of the API at pH levels of 3 and 12, with contact angles of 68.92° and 72.56°, respectively, facilitated its transfer from the aqueous to the oil phase. The adsorption of the API at the oil–water interface was 71.56% and 74.69% at pH levels of 3 and 12, respectively, which was significantly higher than that of the emulsions at other pH levels (5, 7, and 9). After 14 days of storage at 4 °C, PEs at pH levels of 3 and 12 did not undergo phase separation, with small and homogeneous droplets. CLSM revealed a monolayer arrangement of the API at the oil–water interface. These results indicate that PE is more stable at pH levels of 3 and 12 than at other pH levels (5, 7, and 9). In addition, the stabilized astaxanthin PE showed the largest astaxanthin encapsulation (91.43%) at a pH of 3. The emulsions had significantly lower a* values and higher L* values at a pH of 3 compared to a pH of 12, indicating better astaxanthin stability in the PEs. These results will help to expand the application of API-PE loaded with astaxanthin at different pH values. Full article

In order to solve the problem of gas channeling during CO₂ flooding in low-permeability reservoirs, a novel CO₂ responsive gel channeling system was prepared by using carrageenan, branched polyethylene imide and ethylenediamine under laboratory conditions. Based on the Box–Behnken response surface design method, the optimal synthesis concentration of the system was 0.5 wt% carrageenan, 2.5 wt% branchized polyethylenimide and 6.5 wt% ethylenediamine. The micromorphology of the system before and after response was characterized by scanning electron microscopy. The rheology and dehydration rate were tested under different conditions. The channeling performance and enhanced oil recovery effect of the gel system were simulated by a core displacement experiment. The experimental results show that the internal structure of the system changes from a disordered, smooth and loosely separated lamellae structure to a more uniform, complete and orderly three-dimensional network structure after exposure to CO₂. The viscosity of the system was similar to aqueous solution before contact with CO₂ and showed viscoelastic solid properties after contact with CO₂. The experiment employing dehydration rates at different temperatures showed that the internal structure of the gel would change at a high temperature, but the gel system had a certain self-healing ability. The results of the displacement experiment show that the plugging rate of the gel system is stable at 85.32% after CO₂ contact, and the recovery rate is increased by 17.06%, which provides an important guide for the development of low-permeability reservoirs. Full article

The acoustic temperature measurement method has a broad application prospect due to its advantages of high precision, non-contact, etc. It is expected to become a new method for hidden fire source detection in mines. The acoustic time of flight (TOF) can directly affect the accuracy of acoustic temperature measurement. We proposed a quadratic correlation-based phase transform weighting (PHAT-β) algorithm for estimating the time delay of the acoustic temperature measurement of a loose coal. Validation was performed using an independently built experimental system for acoustic temperature measurement of loose coals under multi-factor coupling. The results show that the PHAT-β algorithm estimated acoustic TOF values closest to the reference line as the sound travelling distance increased. The results of coal temperature inversion experiments show that the absolute error of the PHAT-β algorithm never exceeds 1 °C, with a maximum value of 0.862 °C. Using the ROTH weighted error maximum, when the particle of the coal samples is 3.0–5.0 cm, the absolute error maximum is 4.896 °C, which is a difference of 3.693 °C from the error minimum of 1.203 °C in this particle size interval. The accuracy of six algorithms was ranked as PHAT-β > GCC > PHAT > SCOT > HB > ROTH, further validating the accuracy and reliability of the PHAT-β algorithm. Full article

This study applied direct-contact ultrasound-assisted Vacuum Far-Infrared (VFIR) to dry Cistanche slices, investigating the influence of radiation temperature (45 °C, 55 °C, 65 °C), ultrasonic frequency (20 kHz, 40 kHz, 60 kHz) and ultrasonic power (72 W, 96 W, 120 W) on the physicochemical properties, drying characteristics, and microstructure of Cistanche slices. The results showed that the application of ultrasound had a significant enhancement effect on the drying process, with drying time decreasing as radiation temperature, ultrasonic power, and ultrasonic frequency increased. The drying rate curves under three experimental factors exhibited a brief acceleration stage followed by a deceleration stage. Under different drying conditions, the contents of Iridoid and phenylethanoid glycosides in dried products were higher than those under natural drying (ND). Specifically, the content of catalpol at 55 °C, 96 W, 40 kHz (0.56 mg/g) and the content of Leonuride at 55 °C, 96 W, 60 kHz (0.67 mg/g) increased by 1.81 and 1.9 times, compared to ND. The rest of the nutrient content and antioxidant activity increased with the increase in ultrasonic frequency. Compared to ND, ultrasonic-assisted VFIR drying improved the color and rehydration capacity of dried products. Observation of the microstructure revealed that the application of ultrasound made the interior of Cistanche slices loose and porous. In summary, ultrasonic-assisted VFIR drying not only enhances the drying rate but also improves the quality of dried products. Full article

Three-dimensional concrete printing (3DCP) is of great interest to scientists and the construction industry to bring automation to structural engineering applications. However, studies on the thermal performance of three-dimensional printed concrete (3DPC) building envelopes are limited, despite their potential to provide a long-term solution to modern construction challenges. This work is a numerical study to examine the impact of infill geometry on 3DPC lattice envelope thermal performance. Three different lattice structures were modeled to have the same thickness and nearly equal contour lengths, voids, and insulation percentages. Additionally, the effects of filament width and the application of granular insulating materials (expanded polystyrene beads and loose-fill perlite) were also studied. Finally, the efficacy of insulation was established. Results show that void area affects the thermal performance of 3DPC envelopes under stagnant air conditions, while web length, filament width, and contact (intersection) area between the webs and face shells affect the thermal behavior when cavities are filled with insulating materials due to thermal bridging. The thermal efficiency of insulation, which shows the effective use of insulation, varies between 26 and 44%, due to thermal bridges. Full article

The current scallop fishery sector allows many scallops to remain in specified fishing zones, and this process leads to heavy losses in the sector. Scallop fishermen aim to harvest the remaining scallops to reduce their losses. To achieve this, a fisherman must understand the scallop ecology on the seafloor. In our previous study, we proposed a method for measuring scallops using wheeled robots. However, a wheeled robot must be able to resist disturbance from the sea to achieve high measurement accuracy. Strong anchoring of wheels against the seafloor is necessary to resist disturbance. To better understand anchoring performance, we confirmed the wheel anchoring capacity in water-containing sand in an experiment. In this experiment, we towed fixed wheels on water-containing sand and measured the resistance force acting between the wheel and the sand. Afterward, we considered the resistance force as the wheel anchoring capacity on the water-containing sand. The experimental results capture the tendency for the anchoring capacity of sand with/without water to increase with sinkage. The results also demonstrate that the anchoring capacity of water-containing sand is lower than that of non-water-containing sand. However, the results indicate that when the wheels possess lugs, their presence tends to increase the wheels’ anchoring capacity in water. Full article

Soot combustion experiments with 5%O₂/He were conducted using model soot, and four distinct compositions of Ce_xPr_1-xO_2-δ oxides of varying nominal cerium compositions (x = 0, 0.2, 0.3, and 1) were prepared. The catalyst samples were comprehensively characterized using techniques such as XRD, Raman spectroscopy, HR-TEM, N₂ adsorption at −196 °C, XPS, O₂-TPD, H₂-TPR, and work function measurements. The Pr-rich compositions, ranging from Ce_0.3Pr_0.7O_2-δ to PrO_2-δ, resulted in a significant increase in the total evolved O₂ amounts and enhanced catalyst reducibility. However, a decrease in the textural properties of the catalysts was noted, which was particularly important for the pure praseodymia under the synthesis route conducted. The catalytic activity was investigated under the two following contact modes of mixing between soot and catalyst: loose and tight. The results revealed that the catalytic performance is associated with the surface contact in tight contact mode and with the combination of surface/subsurface/bulk oxygen mobility and the BET surface area in loose contact mode. Notably, the temperatures estimated at 10% and 50% of the conversion (T₁₀ and T₅₀) parameters were achieved at much lower temperatures than the uncatalyzed soot combustion, even under loose contact conditions. Specifically, the 50% conversion was achieved at 511 °C and 538 °C for Ce_0.3Pr_0.7O₂ and Ce_0.2Pr_0.8O₂, respectively. While no direct correlation between catalytic activity and work function was observed, a significant relationship emerges between work function values and the formation of oxygen vacancies, whatever the conditions used for these measurements. On the other hand, the ability to generate a high population of oxygen vacancies at low temperatures, rather than the direct activation of gas-phase O₂, influences the catalytic performance of Pr-doped ceria catalysts, highlighting the importance of surface/subsurface oxygen vacancy generation, which was the parameter that showed a better correlation with the catalytic activity, whatever the soot conversion value or the mode of contact considered. Full article

So far, little attention has been paid to the investigation on the seismic failure mechanisms of flexible concrete pile groups embedded in the layered soft soil profiles considering the material non-linearities of soil and concrete piles. The purpose of this study is to investigate seismic failure mechanism models of flexible concrete piles with varied groups in silt layered loose sand profiles under horizontal strong ground motions. Three-dimensional finite element models of the pile–soil interaction systems, which include nonlinearities of soil and concrete piles as well as coupling interactions between the piles and soil, were created for Models I, II, and III of the soil domains, encompassing 1x1, 2x2, and 3x3 flexible pile groups with diameters of 0.80 m and 1.0 m. Model I consists of a homogenous sand layer and a bedrock, Models II and III are composed of a five-layered domain with homogeneous sand and silt soil layers of different thicknesses. The linear elastic perfectly plastic constitutive model with a Mohr–Coulomb failure criterion is considered to represent the behavior of the soil layers, and the Concrete Damage Plasticity (CDP) model is used for the nonlinear behavior of the concrete piles. The interactions between the soil and the pile surfaces are modeled by defining tangential and normal contact behaviors. The models were analyzed for the scaled acceleration records of the 1999 Düzce and Kocaeli earthquakes, considering peak ground accelerations of 0.25 g, 0.50 g, and 0.75 g. The numerical results indicated that failure mechanisms of flexible concrete groups occur near the silt layers, and the silt layers have led to a significant increase in the spread area of the damaged zone and the number of damaged elements. Full article

This study aims to elucidate the mechanism by which the ultrasonic loading of metal affects the extraction of small molecular phase substances (low molecular compounds) in tar-rich coal. Tar-rich coal samples were collected from the Huangling mining area in the southeastern Ordos Basin, China. The coal, the leaching solution of the coal, the extraction products, and the extraction residual coal samples with different metal ions loaded by ultrasound were analyzed using field emission scanning electron microscopy, pH detection, gas chromatography–mass spectrometry, a Fourier transform infrared spectrometer, and an X-ray diffractometer. The obtained results indicated that the ultrasonic loading of coal samples with different metal ions (Mn²⁺, Co²⁺, Cu²⁺, Fe²⁺, and Ni²⁺) promoted the extraction of small molecular phase substances in coal and increased the proportion of extracted aliphatic hydrocarbons, alkylbenzene, naphthalene, phenanthrene, and other compounds. The extraction rate of Mn²⁺ was the highest. Compared with the control group, the extraction rate was increased by 212%. After the ultrasonic loading of metal ions, the physical structure of the coal was loose and the contact area of the solvent increased; the degree of branching and the hydrogen enrichment of the residual coal decreased, the aromaticity increased, the interlayer spacing and stacking layers decreased, and the stacking degree and ductility increased. Metal ions exchanged with hydrogen ions in the coal molecules. At the same time, the metal ions were adsorbed in the coal molecules and effectively combined with free electrons in the coal molecules to catalyze; thus, the extraction effect of the small molecular phase of tar-rich coal was improved. This provides a new method for the clean and efficient utilization of tar-rich coal. Full article

Coordinated events of calcium (Ca²⁺) released from the endoplasmic reticulum (ER) are key second messengers in excitable cells. In pain-sensing dorsal root ganglion (DRG) neurons, these events can be observed as Ca²⁺ sparks, produced by a combination of ryanodine receptors (RyR) and inositol 1,4,5-triphosphate receptors (IP3R1). These microscopic signals offer the neuronal cells with a possible means of modulating the subplasmalemmal Ca²⁺ handling, initiating vesicular exocytosis. With super-resolution dSTORM and expansion microscopies, we visualised the nanoscale distributions of both RyR and IP3R1 that featured loosely organised clusters in the subplasmalemmal regions of cultured rat DRG somata. We adapted a novel correlative microscopy protocol to examine the nanoscale patterns of RyR and IP3R1 in the locality of each Ca²⁺ spark. We found that most subplasmalemmal sparks correlated with relatively small groups of RyR whilst larger sparks were often associated with larger groups of IP3R1. These data also showed spontaneous Ca²⁺ sparks in <30% of the subplasmalemmal cell area but consisted of both these channel species at a 3.8–5 times higher density than in nonactive regions of the cell. Taken together, these observations reveal distinct patterns and length scales of RyR and IP3R1 co-clustering at contact sites between the ER and the surface plasmalemma that encode the positions and the quantity of Ca²⁺ released at each Ca²⁺ spark. Full article

A series of Co-M (M = Fe, Cr, and Mn) catalysts were synthesized by the sol-gel method for soot oxidation in a loose contact mode. The Co-Fe catalyst exhibited the best catalytic activity among the tested samples, with the characteristic temperatures (T₁₀, T₅₀, and T₉₀) of 470 °C, 557 °C, and 602 °C, respectively, which were 57 °C, 51 °C, and 51 °C lower than those of the CoO_x catalyst. Catalyst characterizations of N₂ adsorption–desorption, X-ray diffraction (XRD), X-ray photo-electron spectrometry (XPS), and the temperature programmed desorption of O₂ (O₂-TPD) were performed to gain insights into the relationships between the activity of catalytic soot oxidation and the catalyst properties. The content of Co²⁺ (68.6%) increased due to the interactions between Co and Fe, while the redox properties and the relative concentration of surface oxygen adsorption (51.7%) were all improved, which could significantly boost the activity of catalytic soot oxidation. The effects of NO and contact mode on soot oxidation were investigated over the Co-Fe catalyst. The addition of 1000 ppm of NO led to significant reductions in T₁₀, T₅₀, and T₉₀ by 92 °C, 106 °C, and 104 °C, respectively, compared to the case without the NO addition. In the tight contact mode, the soot oxidation was accelerated over the Co-Fe catalyst, resulting in 46 °C, 50 °C, and 50 °C reductions in T₁₀, T₅₀, and T₉₀ compared to the loose contact mode. The comparison between real soot and model Printex-U showed that the T₅₀ value of real soot (455 °C) was 102 °C lower than the model Printex-U soot. Full article

When nanoparticles are introduced into the bloodstream, plasma proteins accumulate at their surface, forming a protein corona. This corona affects the properties of intravenously administered nanomedicines. The firmly bound layer of plasma proteins in direct contact with the nanomaterial is called the “hard corona”. There is also a “soft corona” of loosely associated proteins. While the hard corona has been extensively studied, the soft corona is less understood due to its inaccessibility to analytical techniques. Our study used dynamic light scattering to determine the dissociation constant and thickness of the protein corona formed in solutions of silica or gold nanoparticles mixed with serum albumin, transferrin or prothrombin. Multivariate analysis showed that the nanoparticle material had a greater impact on binding properties than the protein type. Serum albumin had a distinct binding pattern compared to the other proteins tested. This pilot study provides a blueprint for future investigations into the complexity of the soft protein corona, which is key to developing nanomedicines. Full article