Synergistic demulsification of water-in-crude oil emulsions by bentonite-sds blends: mechanism and performance characterization

The present Special Issue titled "Mechanical Performance and Microstructural Characterization of Light Alloys" aims to report the close relation between mechanical performance and microstructure in light alloys, such as Al, Mg, Ti, and their alloys [...].

The market for polyamide desalination membranes is expected to continue to grow during the coming decades. Purification of alternative water sources will also be necessary to meet growing water demands. Purification of produced water, a byproduct of oil and gas production, is of interest due to its dual potential to provide water for beneficial use as well as to reduce wastewater disposal costs. However, current polyamide membranes are prone to fouling, which decreases water flux and shortens membrane lifetime. This research explored surface modification using poly(ethylene glycol) diglycidyl ether (PEGDE) to improve the fouling resistance of commercial polyamide membranes. Characterization of commercial polyamide membrane performance was a necessary first step before undertaking surface modification studies. Membrane performance was found to be sensitive to crossflow testing conditions. Concentration polarization and feed pH strongly influenced NaCl rejection, and the use of continuous feed filtration led to higher water flux and lower NaCl rejection than was observed for similar tests performed using unfiltered feed. Two commercial polyamide membranes, including one reverse osmosis and one nanofiltration membrane, were modified by grafting PEGDE to their surfaces. Two different PEG molecular weights (200 and 1000) and treatment concentrations (1% (w/w) and 15% (w/w)) were studied. Water flux decreased and NaCl rejection increased with PEGDE graft density ({micro}g/cm{sup 2}), although the largest changes were observed for low PEGDE graft densities. Surface properties including hydrophilicity, roughness and charge were minimally affected by surface modification. The fouling resistance of modified and unmodified membranes was compared in crossflow filtration studies using model foulant solutions consisting of either a charged surfactant or an oil in water emulsion containing n-decane and a charged surfactant. Several PEGDE-modified membranes demonstrated improved fouling resistance compared to unmodified membranes of similar initial water flux, possibly due to steric hindrance imparted by the PEG chains. Fouling resistance was higher for membranes modified with higher molecular weight PEG. Fouling was more extensive for feeds containing the cationic surfactant, potentially due to electrostatic attraction with the negatively charged membranes. However, fouling was also observed in the presence of the anionic surfactant, indicating hydrodynamic forces are also responsible for fouling.

Asphalt pavement, which is mainly made up of the asphalt mixture, exhibits complicated mechanical behaviors under the combined effects of moving vehicle loads and external service environments. Multi-scale numerical simulation can well characterize behaviors of asphalt materials and asphalt pavement, and the essential research progress is systematically summarized from an entire view. This paper reviews extensive research works concerning aspects of the design, characterization, and prediction of performance for asphalt materials and asphalt pavement based on multi-scale numerical simulation. Firstly, full-scale performance modeling on asphalt pavement is discussed from aspects of structural dynamic response, structural and material evaluation, and wheel-pavement interaction. The correlation between asphalt material properties and pavement performance is also analyzed, and so is the hydroplaning phenomenon. Macro- and mesoscale simulations on the mechanical property characterization of the asphalt mixture and its components are then investigated, while virtual proportion design for the asphalt mixture is introduced. Features of two-dimensional and three-dimensional microscale modeling on the asphalt mixture are summarized, followed by molecular dynamics simulation on asphalt binders, aggregates, and their interface, while nanoscale behavior modeling on asphalt binders is presented. Finally, aspects that need more attention concerning this study's topic are discussed, and several suggestions for future investigations are also presented.

This paper presents the results of a research study that investigated the impact of varying amounts of coconut fiber, acting as a stabilizer, on the thermo-mechanical characteristics of compressed earth blocks (CEBs) samples. In this study, parallelepipedal CEBs samples were formed with different fiber contents: 0%, 0.2%, 0.4%, 0.6%,  0.8%, and 1%. Six mixtures were created by incorporating different proportions of fiber into locally available soil. The inclusion of fiber significantly enhances the ultimate strengths of the CEBs samples, reaching a maximum improvement at optimal fiber content of 0.8%. However, this improvement is accompanied by a slight increase in the thermal conductivity of the material. Overall, the addition of coconut fibers enhances the thermal and mechanical properties of the CEBs. Received: August 30, 2023Accepted: October 12, 2023

Characterization of mechanical performance of concrete beams with external reinforcement by acoustic emission and digital image correlation

The integration of compliant mechanism and parallel mechanism provide an effective solution for medical micromanipulation, especially for the scenarios where high precision and high dexterity are required. The development of spatial compliant parallel mechanism (CPM) takes advantages of the features for both compliant mechanism and parallel mechanism to generate greater comprehensive performances. In this research, a novel three degrees-of-freedom CPM is designed and analyzed. Since performance characterization is one important factor that greatly affects the application potential, the performance indices including stiffness, dexterity, manipulability and workspace are mapped respectively. The finite element analysis is conducted to prove the feasibility of the proposed design. The multi-parameters improvement is implemented to demonstrate a way how to optimize the performance of the compliant parallel mechanism based on a generic method.

In order to elevate the allowable current density of pyrophosphate bath, glycerol was employed as additive for copper electrodeposition, and its influences on cathodic current efficiency, coordination environment, electrodeposition behavior and coating properties of conventional pyrophosphate bath were systematically investigated. It was demonstrated that glycerol did not change the coating's nucleation mechanism and purity, and had almost no effect on the bath's current efficiency, but effectively improved the allowable current density, increased the cathodic over-potential, and suppressed the hydrogen evolution in copper electrodeposition processes by absorption onto electrode surface. Specially, the coating electrodeposited from this optimized bath also had lower porosity and smaller micro-strain than that of produced from conventional pyrophosphate bath. Detailed analyses were conducted to clarify the mechanism responsible for the improvements.

High-modulus engineered cementitious composites: Design mechanism and performance characterization

Multi-field and multi-scale characterization of novel super insulating panels/systems based on silica aerogels: Thermal, hydric, mechanical, acoustic, and fire performance

The development of transportation infrastructures has led to the need of huge earthmoving volumes, resulting in high embankments. In the construction of these embankments, rockfill and soil-rock mixture materials have been used. A 25 km roadway section, in the North of Portugal, with the difficult topographic conditions, has required the construction of large embankments. The involved formations are essentially granite (South area) and schist and greywacke (North area). To optimize the construction procedure and to evaluate their performance, physical and mechanical characterization of the materials was carried out and monitoring equipments were installed in some embankments. For that purpose, five embankments were selected, taking into account, essentially, the geometry and type of material used in their construction. Plate load tests were also performed, aiming at the evaluation of the deformation modulus of the embankments. In order to measure displacements, vertical and horizontal inclinometers, extensometers and pressure cells systems were installed during construction. After construction, topographic marks on the embankment surface were installed. In this paper, the results of the mechanical characterization carried out in situ and in the laboratory (large triaxial and oedometer tests) are presented. The installed monitoring equipments are also described. The displacements during the construction and deformations in service are herein presented.

Lattice structures manufactured via additive manufacturing (AM) technologies offer substantial potential for application-specific energy absorption solutions across automotive, aerospace, and medical sectors, yet systematic frameworks for translating performance requirements into manufacturable design parameters remain limited. This investigation examines the mechanical behavior and manufacturing repeatability of Face-Centered Cubic (FCC) and Diamond lattice architectures produced through binder jetting (BJ) technology of thermoplastic polyurethane (TPU) across four density levels, with comprehensive characterization of energy absorption performance and failure mechanisms. Uniaxial compression testing was conducted, with detailed analysis of deformation behavior, densification characteristics, and manufacturing consistency. The deformation evolution of the analyzed structures was captured by a digital camera and analyzed through Digital Image Correlation (DIC). Finite element model was also involved to better understand the stress and strain of different structures. Diamond lattice structures demonstrated superior energy absorption performance with 35–45% higher specific energy absorption capacity compared to equivalent-density FCC architectures, exhibiting progressive loading characteristics and extended useful deformation range beyond 60% strain. Manufacturing repeatability analysis revealed coefficient of variation values below 10% for Diamond structures across all mechanical properties, indicating process maturity suitable for mass customization applications. These results validate binder jetting technology for reliable production of customized lattice-based energy absorption components, providing a systematic framework for application-specific lightweight design across multiple industrial sectors.

The use of fiber-reinforced polymer (FRP) composites, in the form of externally bonded reinforcement for rehabilitation or in the form of externally bonded reinforcement for rehabilitation of in the form of reinforcing bars and tendons for new reinforcement, provides a potential means of slowing or even preventing, the deterioration seen in conventional materials such as steel and concrete. However, there is a concern regarding the long-term durability of E-glass reinforced FRP with concrete. This article presents the results from a 75-week investigation aimed at characterization of deterioration mechanisms and performance of E-glass/vinylester in an alkaline environment. The study used dynamic mechanical thermal analysis, Fourier-transform infrared spectroscopy, gravimetric moisture uptake, tensile and short-beam-shear tests, and microscopy. Results show a range of deterioration mechanisms initiating with reversible plasticization of the resin and transitioning to irreversible fiber-matrix debonding, hydrolysis, and chain scission of the resin, and pitting and material loss of the fiber. Reconditioning, following periods of immersion, results in some regain in tensile strength over at least half the exposure period, whereas after 15 weeks there is almost no regain in interlaminar shear strength. The authors predict that long-term response will match fairly closely with experimental results at the 75-week level. Under self-similar continuation of deterioration, 26.89% of the original tensile strength and 58.24% of the short-beam-shear strength can be expected to be retained after 50 years. The authors conclude with a brief discussion of real-life conditions versus the testing conditions.

Abstract4,4’‐azobis(1,2,4‐triazole) (ATRZ), as a representative of high‐nitrogen compound, has attracted extensive interests. This work explores the thermal decomposition mechanism and combustion performance of ATRZ. The thermogravimetry‐differential scanning calorimetry‐fourier transform infrared spectroscopy (TG‐DSC‐FTIR) of ATRZ was carried out at heating rate of 10 °C/min in an argon atmosphere. ATRZ has two peak exothermic temperatures, 110.24 °C and 306.85 °C respectively. The exothermic peak at 110.24 °C is the decomposition of ATRZ tiny debris, and the exothermic peak at 306.85 °C is the decomposition of the main part of ATRZ. The pyrolysis‐gas chromatography mass spectrometry (PY‐GC/MS) of ATRZ was carried out at 350 °C in an argon atmosphere. By combining TG‐DSC‐FTIR and PY‐GC/MS, the thermal decomposition mechanism of ATRZ was speculated. The main reaction in the ATRZ pyrolysis process is the cleavage of two N−N single bonds in the nitrogen bridge, forming a nitrogen molecule and two triazole rings, which is the majority of the first step decomposition reaction. At the same time, a small number of triazole rings break off to form other intermediates. A small amount of nitrogen gas is generated and a large number of CN clusters are formed. Under the same testing conditions, ATRZ has a higher combustion heat (19318 J/g) than other traditional CHNO energetic materials. By comparing the laser ignition combustion of ATRZ and ATRZ+RDX, the combustion temperature of ATRZ+RDX is higher and the combustion duration is longer. The introduction of CHNO type ammonium nitrate explosives promotes the energy release of ATRZ.

IntroductionDespite the extensive mechanistic and pathological characterization of the amyloid precursor protein (APP)/presenilin-1 (PS-1) knock-in mouse model of Alzheimer's disease (AD), very little is known about the AD-relevant behavioral deficits in this model. Characterization of the baseline behavioral performance in a variety of functional tasks and identification of the temporal onset of behavioral impairments are important to provide a foundation for future preclinical testing of AD therapeutics. Here we perform a comprehensive behavioral characterization of this model, discuss how the observed behavior correlates with the mechanistic and pathological observations of others, and compare this model with other commonly used AD mouse models.MethodsFour different groups of mice ranging across the lifespan of this model (test groups: 7, 11, 15, and 24 months old) were run in a behavioral test battery consisting of tasks to assess motor function (grip strength, rotor rod, beam walk, open field ambulatory movement), anxiety-related behavior (open field time spent in peripheral zone vs. center zone, elevated plus maze), and cognitive function (novel object recognition, radial arm water maze).ResultsThere were no differences in motor function or anxiety-related behavior between APP/PS-1 knock-in mice and wild-type counterpart mice for any age group. Cognitive deficits in both recognition memory (novel object recognition) and spatial reference memory (radial arm water maze) became apparent for the knock-in animals as the disease progressed.ConclusionThis is the first reported comprehensive behavioral analysis of the APP/PS1 knock-in mouse model of AD. The lack of motor/coordination deficits or abnormal anxiety levels, coupled with the age/disease-related cognitive decline and high physiological relevance of this model, make it well suited for utilization in preclinical testing of AD-relevant therapeutics.

Ordered graphitized ceramic layer induced by liquid crystal epoxy resin in silicone rubber composites with enhanced ablation resistance performance