Compact Layer Research Articles

Direct shear behaviors of excavated clay reinforced with geocomposite drainage layer encapsulated in thin sand layers.

The objective of this study is to assess the effectiveness of a novel structure comprising a geocomposite drainage layer and a thin sand layer (GDL + sand) in mitigating the rapid dumping of excavated clay and its associated issues, such as landslides. Two sets of direct shear tests were conducted to investigate the influence of sand layer thickness and compaction degree on the interface shear behavior of the GDL + sand structure. As the sand layer thickness increased, both the interface shear strength and friction angle gradually increased, first more sharply and then at a slower rate toward stability, while the interface cohesion decreased gradually. The optimal sand layer thickness for achieving the most effective reinforcement in stabilizing the clay was identified as 10 mm. A higher sand layer compaction degree was found to result in increased interface shear strength, interface friction angle, and interface cohesion. Building on these findings, the reinforcing efficiency of the GDL + sand structure was investigated through mechanism analysis in comparison to that of a geogrid + sand structure and GDL structure as per the interface friction coefficient. The ranking of interface friction coefficients among the three structures emerged as: geogrid + sand > GDL + sand > GDL. These results suggests that the GDL + sand structure exhibits superior reinforcement efficiency compared to the GDL structure and offers better drainage efficiency than the geogrid + sand structure.

Enhanced oxidation resistance of HfB2‐SiC‐ZrSi2 coating at 1700°C through low‐loss film‐forming treatment

AbstractTo enhance the oxidation resistance of HfB2‐SiC‐ZrSi2 coating, low‐loss film‐forming treatment (LFT) was employed to generate high‐quality oxygen barrier glass layers, and the modification effect of varying formation temperature on the oxidation resistance was investigated at 1700°C. The results demonstrated that, with LFT at 1500°C, the relatively modest oxidation activity and complete dispersion of metal oxide nanocrystals generated a compact and continuous composite glass layer, which caused a decreased oxidation activity at 1700°C. The excessive formation temperature might result in oxidized and porous coatings, while lower temperatures could lead to poor fluidity of the glass layer, rendering it challenging to achieve compact composite glass layers. The coating sample with LFT at 1500°C exhibited a carbon loss rate of 0.33 × 10−6 g·cm−2·s−1 and an oxygen permeability level of 0.28%, respectively, when oxidized at 1700°C. These results provide fundamental insights into the oxidation resistance mechanisms within the modified HfB2‐SiC‐ZrSi2 coating system.

Superior anti-oxidation layer induced by PVA-boehmite sol-gel film on AISI304 steel

The superior anti-oxidation layer induced by the PVA-boehmite sol-gel film on the AISI304 steel during the cyclic oxidation is investigated in this work. The moderate PVA addition in the boehmite sol conduces to increase the film thickness and is beneficial to the adhesion between the film and the substrate. The presence of the PVA-boehmite film leads to a significant reduction in mass gain during the high-temperature cyclic oxidation at 800 °C, demonstrating the enhanced oxidation resistance. The generated oxide layer induced by the PVA-boehmite film presents as a thin, compact, and continuous layer without spalling, offering sustainable protection against oxidation etching. The PVA-boehmite film promotes the preferential formation of the corundum (Al, Cr)2O3 phase rather than the detrimental hematite Fe2O3 phase during the oxidation procedure, which facilitates the development of the above compact oxide layer. Finally, the superior anti-oxidation oxide layer is characterized as a novel dual-layer structure: the outer spinel MnCr2O4 layer and the inner corundum (Al, Cr)2O3 layer, effectively delaying the oxidation process.

Effect of a low‐mineralized thermal spring water on skin barrier mechanical properties using atomic force microscopy

AbstractThe mineral content of thermal spring water (TSW) applied to the skin surface can directly influence the skin barrier. Indeed, our previous study showed that Avène TSW (ATSW), a low mineral content thermal spring water, protects the stratum corneum from dehydration compared to a mineral‐rich TSW (MR‐TSW) and maintains skin surface ultrastructure. While many TSWs have been recognized to have beneficial effects on skin, little is known about their localized and specific effects on skin barrier biomechanics at the nanometric scale. The aim of this study was to compare the effects of ATSW with a reference, MR‐TSW, on the biomechanical barrier properties of the skin under homeostasis conditions using atomic force microscopy (AFM). AFM was used to obtain a precise nanomechanical mapping of the skin surface after three applications of both TSW. This provides specific information on the skin topographical profile and elasticity. The topographic profile of skin samples showed a specific compaction of the skin layers after application of MR‐TSW, characterized by an increase of the total number of external skin layers, compared to non‐treated samples. By contrast, ATSW did not modify the skin topographic profile. High‐resolution force/volume acquisitions to capture the elastic modulus showed that it was directly correlated with skin rigidity. The elastic modulus strongly and significantly increased after MR‐TSW application compared to non‐treated skin. By contrast, applications of ATSW did not increase elastic modulus. These data demonstrate that applications of MR‐TSW significantly modified skin barrier properties by increasing skin surface layer compaction and skin rigidity. By contrast, ATSW did not modify the topographical profile of skin explants nor induce mechanical stress at the level of the stratum corneum, indicating it does not disrupt the biophysical properties linked to skin surface integrity.

Influence of rolling reduction on corrosion behavior of WE43 alloy

The corrosion behavior of WE43 alloy with different rolling reductions (0%, 25%, 45%, and 80%) at 500 °C was investigated in 3.5 wt.% NaCl solution. The microstructure evolution of the rolled WE43 alloy was characterized in detail by means of optical microscopy (OM), transmission electron microscopy (TEM) and electron back-scattered diffraction (EBSD). The results show that with increasing reductions, basal texture is gradually enhanced and grain size gradually decreases. Only the alloy with 45% reduction exhibits dispersed dynamic precipitates. Immersion and electrochemical measurements demonstrate the decreasing order of the corrosion resistance of the rolled WE43 alloy: 45% reduction > 80% reduction > 25% reduction > 0 reduction. The best corrosion resistance of the WE43 alloy with 45% reduction is mainly related to a large number of finely dispersed precipitates, which are capable of promoting the formation of a compact corrosion product layer. The increased corrosion rate of the sample with 80% reduction is induced by the re-solution of the majority of precipitates into the matrix. The grain size, basal texture and deformation twins have a limited effect on the corrosion resistance of rolled WE43 alloy compared with the precipitates.

Equivalence study of the resin-dentine interface of internal tunnel restorations when using an enamel infiltrant resin with ethanol-wet dentine bonding

This preregistered ex vivo investigation examined the dentinal hybrid layer formation of a resinous infiltrant (Icon), with reference to both thickness (HLT) and homogeneity when combined with modified tunnel preparation (occlusal cavity only) and internal/external caries infiltration. The adhesives Syntac and Scotchbond MP were used as controls (Groups 1 and 3) or in combination with Icon (Groups 2 and 4). A split-tooth design using healthy third molars from 20 donors resulted in 20 prepared dentine cavities per experimental group. The cavity surfaces (n = 80) were etched (37% H3PO4), rinsed, and air-dried. Rewetting with ethanol was followed by application of the respective primers. After labeling with fluorescent dyes, either Syntac Adhesive/Heliobond or Scotchbond MP Adhesive was used alone or supplemented with Icon. HLT, as evaluated by scanning electron microscopy, did not significantly differ (P > 0.05), and confocal laser scanning microscopy revealed homogeneously mixed/polymerized resin-dentine interdiffusion zones in all groups. Icon can be successfully integrated into an ethanol-wet dentine bonding strategy, and will result in compact and homogeneous hybrid layers of comparable thickness considered equivalent to the non-Icon controls, thus allowing for preservation of the tooth’s marginal ridge and interdental space in the case of internal/external infiltration of proximal caries.

Enhancing the protective performance of anti-impact, corrosion resistant and flame retardant polyurea coatings using bio-based supramolecular decorated montmorillonite

Developing bio-based nano-additives for enhancing mechanical strength, corrosion resistance, and flame retardancy in polyurea (PUA) coatings at low loading levels is crucial for human well-being and environmental preservation. In this study, montmorillonite (MMT) was first exfoliated by ball milling with the aid of chitosan, and then further co-assembled with phytic acid and urea to form a nanohybrid (CPN@MMT). The resulting CPN@MMT nanohybrid exhibited good compatibility and dispersibility within matrix and endowed PUA composites with improved anti-impact, corrosion resistant and flame retardant properties. Remarkably, the addition of CPN@MMT improved the mechanical and impact protection properties of PUA coatings. Electrochemical and salt spray tests confirmed that the excellent anti-corrosion performance of PUA composite coating stemmed from the dispersed nano-sheets forming a protective nano-barrier. CPN@MMT in the PUA matrix formed a compact char layer, reducing heat release and smoke by inhibiting heat diffusion and volatile gas evaporation, as evidenced by cone calorimeter and TG-FTIR tests. The enhanced fire safety was primarily attributed to the physical barrier, catalytic charring and dilution effect of CPN@MMT. Hence, a green and feasible method was developed to create bio-based nano-additive in PUA coatings with anti-impact, corrosion resistant and flame retardant performance.

The smooth-walled human RVOT contains trabeculations that cause conduction delay

Abstract Funding Acknowledgements None. Background The right ventricular outflow tract (RVOT) is the outlet from the right ventricle and is the initiating substrate of life-threatening arrhythmias. While the luminal wall of the RVOT is often assumed to be without the complex trabecular meshwork that characterizes the right ventricular free wall, the anatomy of the RVOT is an understudied subject. Aim to investigate whether trabeculations occur in the RVOT and to assess whether this impacts electrical propagation. Methods Human hearts were investigated using high-resolution MRI, histology, RNA-sequencing, and optical and electrical mapping. Results We used high-resolution MRI and serial sectioning to reconstruct the macroscopic details of the human RVOT and identified cases exhibiting much trabeculation. The smooth lumen of the RVOT varied between 9% and 23% of the total RV anterior surface (N=11). Histological analysis on additional six hearts indicated that the RVOT compact layer is thinner when trabeculations are present. RNA sequencing of four human donor hearts revealed enrichment in the subendocardial region of 88 genes associated with cardiac conduction and trabeculations (P adjusted<0.05). Finally, we selected two human donor hearts showing trabeculations in the RVOT from which we generated wedge preparation and performed optical and electrical mapping. The trabecular regions demonstrated high degree of fractionation when compared to non-trabeculated regions, which coincided with delayed activation. Conclusion Trabeculations are found in the RVOT, and their extent varies among individuals. This impacts on the thickness of the compact wall in the RVOT, restricting the depth of tissue at which clinical interventions can be performed, as well as influencing electrical propagation and possible arrhythmogenicity.

Enhanced OER performance by varying Al-WO3 electrocatalyst thickness: Process optimization

Oxygen evolution reactions (OER) are highly significant and play a critical role in the advancement of fuel cells, electrolyzers, chemicals, and solar energy conversion devices. The challenge in the quest is attributed to the absence of an efficient electrocatalyst assembly that functions optimally. A simple method of electrodeposition of Al:WO3 on a fluorinated tin oxide (FTO) electrode was used to investigate the OER in this study. The electrodepositions were achieved by employing a three-electrode cell at various scan rates ranging from 10 to 100 mV/s. During this investigation, the influence of the scan rate on electrocatalyst loadings and the impact of electrocatalyst layer thickness on the OER were examined. The electrodepositions of Al:WO3@FTO were analyzed using a range of optical, chemical, and physical techniques such as SEM, XRD, FT-IR, Raman spectroscopy, EDX, EDS mapping, and electrochemical tests. The FTIR and Raman analysis confirmed the synthesis of AL:WO3 while the peaks detected at angles 38.7° and 43° by XRD with planes (111) and (200), served as a distinctive characteristic for identifying aluminum (Al). The peaks observed at angles of 27.8°, 30.7°, 33°, 50.45°, and 58° correspond to WO3 material. The characterization techniques also confirmed that the synthesized material is highly crystalline in nature. The OER potential using Al:WO3@FTO electrodes with different electrocatalyst thicknesses, ranging from 8 nm to 31 nm was investigated by studying various electrochemical techniques such as CV, LSV, CPE, Tafel slope, HP2P splitting, EIS, TOF, short and long-term electrode stability, and double layer capacitance. The linear regression coefficient (R2) was also calculated to measure the relationship between the electrocatalyst's thickness and each electrochemical test. The findings indicated that increasing the scan rates resulted in thinner and denser electrodepositions on the FTO substrate as the thinnest film was formed at 100 mV/s. An inverse relationship between electrocatalyst layer thickness and OER activity was observed. The electrode with the thinnest and most compact electrocatalyst layer, specifically ED Al:WO3@FTO08, exhibited the lowest onset potential of 1.48 V and a maximum current of 84 mA/cm2 at 1.76 V. It also demonstrated superior reaction kinetics, as evidenced by its lower Tafel slope value of 49 mV/dec, which is the lowest among all the electrodes that were prepared. In particular, the electrode with a thin and compact electrocatalyst layer worked better in OER operations than the other five electrodes that had higher amounts of Al:WO3.

Preparation of UiO-66 MOF-Bonded Porous-Layer Open-Tubular Columns Using an In Situ Growth Approach for Gas Chromatography.

The thermally stable zirconium-based MOF, UiO-66, was employed for the preparation of bonded porous-layer open-tubular (PLOT) GC columns. The synthesis included the in situ growth of the UiO-66 film on the inner wall of the capillary through a one-step solvothermal procedure. SEM-EDX analysis revealed the formation of a thin, continuous, uniform, and compact layer of UiO-66 polycrystals on the functionalized inner wall of the column. The average polarity (ΔIav = 700) and the McReynolds constants reflected the polar nature of the UiO-66 stationary phase. Several mixtures of small organic compounds and real samples were used to evaluate the separation performance of the fabricated columns. Linear alkanes from n-pentane to n-decane were baseline separated within 1.35 min. Also, a series of six n-alkylbenzenes (C3-C8) were separated within 3 min with a minimum resolution of 3.09, whereas monohalobenzene mixtures were separated at 220 °C within 14s. UiO-66 PLOT columns are ideally suited for the isothermal separation of chlorobenzene structural isomers at 210 °C within 45 s with Rs ≥ 1.37. The prepared column featured outstanding thermal stability (up to 450 °C) without any observed bleeding or significant impact on its performance. This feature enabled the analysis of various petroleum-based samples.

Innovative multifunctional fire retardance of poly(butylene adipate-co-butylene terephthalate)-based bio-composite formulation

Poly(butylene adipate-co-butylene terephthalate) (PBAT), a biodegradable aromatic-aliphatic copolyester, has been widely applied in various fields, but it shows the flammability, resulting in serious fire risk. The flame retardancy of some PBAT/polymer blend systems have been studied, but that of neat PBAT was seldom reported. In particular, the research and development of the bio-based green flame retardant agent is highly desired. In this work, fully bio-derived modified chitosan particles (C-CS), were synthesized and used to prepare a novel PBAT-based multifunctional flame-retardant composite. The PBAT/3%C-CS composite (PC3) exhibited an excellent anti-dripping and self-extinguishing performance and achieved the highest fire safety rating (V-0). Peak of heat release rate and total heat release reduced by 39.8 % and 14.9 %, respectively. The char residue yield of the PC3 increased by 211.6 % in the PC3, compared with that of neat PBAT. Both condensed- and gas-phase played dual roles on increasing the flame-retardant performance of the PC3. The PC3 showed a relatively compact and continuous char layer which acted as a physical barrier to suppress the heat exchange and O2 entry (into the matrix) in the combustion process. Meanwhile, the concentration of O2 and H·/HO· free radicals were diluted by a small portion of non-flammable gas products in the pyrolysis process. Also, the PC3 presented elevated crystallizability and anti-bacterial effect, and reduced UV-transmittance characteristic.

Unveiling the initial oxidation mechanism of a single crystal Ni-based superalloy with pre-deformation

The role of pre-deformation on the initial oxidation mechanism of a single crystal Ni- was revealed. With pre-deformation, the recrystallized grain boundaries and dislocations provided sites for the nucleation of Al2O3 and enhanced the diffusion flux of Al irrespective of γ/γ′ interface, γ′, and γ phase. Ultimately, a thin compact α-Al2O3 layer formed, improving the oxidation resistance. Without pre-deformation, Ni and Al atoms diffused along the γ'/γ interface, however, the Al-flux is insufficient to maintain the growth of Al2O3. As a result, a loose multilayer film formed on the surface, which decreased the oxidation resistance.

Oxidation Behaviour of Fe-28Al-5Si at.% Alloyed with Ti and Mo

AbstractThe high-temperature oxidation behaviour of Fe-28Al-5Si, Fe-28Al-5Si-2Mo and Fe-28Al-5Si-2Ti (in at.%) was investigated. Cyclic oxidation tests of iron aluminides were performed at 900°C and 1100°C. The oxidation kinetics and oxidation behaviour (by measuring of total weight gain, etc.) were described. The structure of the alloys’ surfaces after oxidation, as well as the composition and morphology of oxide layers, was analysed by optical microscopy, scanning electron microscopy, SEM–EDS and X-ray diffraction. The beneficial effect of alloying with titanium or molybdenum on the oxidation resistance of Fe-Al-Si-based alloys was observed at temperatures of 900°C and 1100°C. Titanium and molybdenum suppress the formation of eutectic regions of the secondary phase in the structure, which preferentially oxidize. Therefore, a thin and compact alumina layer (only minor amounts of iron oxides and ZrO2) formed on the surface of Fe-28Al-5Si-2Mo and Fe-28Al-5Si-2Ti at 900°C. These alloys maintain low weight gains even at a temperature of 1100°C. On the other hand, alloy Fe-28Al-5Si contains a high number of eutectics-like areas, which causes ingress of the oxidation (selective oxidation of eutectic areas) and breakaway oxidation is observed at 900°C and 1100°C, respectively.

Effect of grain size on defect annealing in displacement-damaged tungsten

Pulsed laser deposition and subsequent thermal treatment were used to create compact tungsten layers with various grain sizes (1μm, 100 nm, and 10 nm). The layers were self-damaged at room temperature up to 0.23 dpa using 20.3 MeV W ions and annealed in vacuum at 473 K or 673 K prior to exposure to deuterium plasma to populate the surviving displacement defects. Thermal desorption spectroscopy was used to measure deuterium retention and study the desorption profile. Rate-equation modeling of the desorption spectra was performed to study the behavior of individual traps at both annealing temperatures. After annealing the 1μm and 100 nm samples at 473 K, the deuterium retention was found to decrease by 24% and 9%, respectively, whereas the total deuterium retention in the 10 nm sample did not change. Annealing at 673 K reduced total deuterium retention by additional 27%, 14%, and 34% in the case of the samples with a grain size of 1μm, 100 nm, and 10 nm, respectively.

РІЗНІ ПРАКТИКИ ОЦІНЮВАННЯ МІЦНОСТІ ШАРІВ ҐРУНТОВОЇ ОСНОВИ І ДИСПЕРСНИХ МАТЕРІАЛІВ ЗА РЕЗУЛЬТАТАМИ ДИНАМІЧНОГО ВИПРОБУВАННЯ КОНУСНИМ ПЕНЕТРОМЕТРОМ

Introduction. The introduction to the paper highlights the methods of standard geotechnical tests for in situ measurements of subgrade strength or strength estimation. Problem statement. The issue of the paper concerns the interpretation and the application of the results of testing of the subgrades or granular layers of a road pavement by the dynamic cone penetrometer. Purpose. The goal of the paper consists of the analysis of practices of the subgrade strength evaluation by the conversion of the dynamic cone penetration test (DCPT) results to the nominal values of the California bearing ratio (CBR) or by plotting the subgrade profile and also of practices for the layer thickness evaluation and compaction control. Results. The main principles of DCPT were reviewed with performing the analysis of factors affecting the test results. The equations of the dependence of the nominal CBR values on the penetration index as the main result of DCPT was analyzed. The assumption was made that the difference in such equations may be determined by the differed confinement conditions under testing in accordance with which the calculated values provided by the results of testing under the triaxial confinement are higher. Also the stair-stepping effect appeared when performing DCPT on cohesive soils was reviewed.

The poly (arylene ether urea) double interface layer formed in PEEU@HfO2/PEI nanocomposites enables enhanced dielectric and energy storage performance

Polyetherimide (PEI) has great potential as a dielectric because of its high-temperature resistance, but its low energy storage density limits practical applications. Incorporating hafnium dioxide (HfO2) with a moderate dielectric constant (k) and wide bandgap can simultaneously enhance the polarization intensity of PEI and potential barriers for charge injection. Nevertheless, the poor compatibility between HfO2 and PEI inevitably introduces defects, thereby weakening the inhibitory effect on dielectric loss. To tackle this issue, an organic double interface layer is introduced to enhance dielectric performance, where the polar poly(arylene ether urea) (PEEU) containing hydrogen bonds can ensure the layer's compactness. Notably, its non-bonding urea groups serve as deep traps to capture migrating carriers, and the gradient k values of HfO2, PEEU, and PEI help mitigate electric field distortions at the interface, therefore enhancing the suppression of conduction loss. The polarity of PEEU and the introduction of multiple interfaces significantly contribute to an increased k (maximum 9.7, at 1 kHz). At 300 kV mm−1, 5 vol% PEEU@HfO2/PEI achieves a discharged energy density of 3.3 J cm−3 and a high charge-discharge efficiency of 83 %, surpassing 5 vol% HfO2/PEI by 1.95 and 2.44 times, respectively. The further COMSOL simulation verifies and proves this work as a novel design strategy for nanocomposite dielectrics.

Halloysite nanotubes immobilized by copper itaconic acid complexes as smoke suppressant for soft polyvinyl chloride

AbstractCurrently, there are few reports of core–shell‐structured smoke suppressants that can provide a growth substrate and stabilize the char layer. In response to this problem, core–shell nanoparticles of halloysite nanotubes (HNTs) coated with copper itaconate complex were prepared by layer‐by‐layer assembly method. The electrostatic forces between HNTs and copper ions and the coordination between the itaconic acid and copper ions contributed this synthesis. The micromorphology, chemical composition, and structure of HNT@CuC5H4O4 were characterized, and its effects on the flame‐retardant and smoke‐inhibition properties, mechanical properties, and thermal stability of the soft polyvinyl chloride (PVC) were investigated. The results showed that the core–shell structure of HNT@CuC5H4O4 contributed to its homogeneous dispersion in PVC and the formation of interlocking mesh structure. Thus, the incorporation of HNT@CuC5H4O4 enhanced the strength and stiffness of soft PVC without sacrificing its ductility. Besides, copper ions on HNT@CuC5H4O4 could promote the cross‐linking carbonization of the PVC at high temperature. The formed char layer catalyzed by CuC5H4O4, together with its attached three‐dimensional network structure of HNT constituted a compact and continuous char layer with high thermal stability, which effectively prevented the release of combustible volatiles and toxic gases as well as heat transfer.

Improving the flame retardancy and smoke suppression of flexible PVC by incorporating zinc borate‐modified diantimony trioxide

AbstractThe properties and structure of flexible PVC by incorporating zinc borate (ZB)‐modified diantimony trioxide (Sb2O3) were investigated. The results of flame retardancy and smoke suppression testing indicate that there was an obvious maximum Limited oxygen index (LOI) value of PVC/20 wt.% ZB–Sb2O3 composites reached 37.5% and passed the UL 94 V‐0 rating. An obvious synergistic effect between ZB and Sb2O3 was observed by LOI, SDR, and TG. Moreover, remarkable decreases in the smoke density were observed when ZB–Sb2O3 was incorporated into PVC. In addition, the tensile strength and elongation at break of PVC/ZB–Sb2O3 composites was higher than PVC/Sb2O3 composites, and this ameliorative effect was mainly arising from the ZB–Sb2O3 nanoparticles, which reduced the degree of fatal defects on PVC. The addition of ZB and Sb2O3 greatly increased the amount of residual char and apparently improved the mechanical properties of PVC composites. According to scanning electron microscopy photographs of residual char, after thermal decomposition, there were many fragments linked to the condensed phase and the compact char layer. Fourier transform infrared spectroscopy shows the residues char was composed of benzene ring, the flame retardants occurred and the condensed phase with significant interactions.

Electrochemical and Mechanical Properties of Hexagonal Titanium Dioxide Nanotubes Formed by Sonoelectrochemical Anodization.

This study aimed to investigate the fabrication and characterization of hexagonal titanium dioxide nanotubes (hTNTs) compared to compact TiO2 layers, focusing on their structural, electrochemical, corrosion, and mechanical properties. The fabrication process involved the sonoelectrochemical anodization of titanium foil in various electrolytes to obtain titanium oxide layers with different morphologies. Scanning electron microscopy revealed the formation of well-ordered hexagonal TNTs with diagonals in the range of 30-95 nm and heights in the range of 3500-4000 nm (35,000-40,000 Å). The electrochemical measurements performed in 3.5% NaCl and Ringer's solution confirmed a more positive open-circuit potential, a lower impedance, a higher electrical conductivity, and a higher corrosion rate of hTNTs compared to the compact TiO2. The data revealed a major drop in the impedance modulus of hTNTs, with a diagonal of 46 ± 8 nm by 97% in 3.5% NaCl and 96% in Ringer's solution compared to the compact TiO2. Nanoindentation tests revealed that the mechanical properties of the hTNTs were influenced by their diagonal size, with decreasing hardness and Young's modulus observed with an increasing diagonal size of the hTNTs, accompanied by increased plastic deformation. Overall, these findings suggest that hTNTs exhibit promising structural and electrochemical properties, making them potential candidates for various applications, including biosensor platforms.

Evaluation of Subtitle D Covers and Exposed Geomembrane Cover for Landfills: Sustainability and Resiliency

Exposed geomembrane covers (EGMs) are considered as suitable alternatives to traditional subtitle D soil covers with compacted clay layers (CCL) for landfill cover applications. Compared to CCLs, which comprise various layers, including vegetation, erosion soil layers, and barrier liners, EGMs offer benefits such as reduced resource use. There are several risks associated with cover systems, ranging from climate-related shocks or stressors such as earthquakes, droughts, and floods to local shocks such as excessive differential settlement due to the uneven degradation of waste mass. Hence, their resilience and sustainability must be analyzed, particularly considering the escalating impact of climate change and the growing need to integrate resilience and sustainability principles into engineering designs and operations. This study comparatively assessed the resilience and sustainability of three cover systems: EGM, soil cover with geomembranes, and soil cover without geomembranes. A ((tiered quantitative life cycle assessment of sustainability and resilience) framework was employed. The resilience assessment was performed using a rating system, considering the technical performance of the cover systems, along with the environmental, economic, and social implications of the failures. Subsequently, a comprehensive sustainability assessment encompassing environmental, economic, and social dimensions was conducted. A life-cycle assessment of all cover systems was performed to evaluate environmental sustainability, and a cost-benefit analysis was employed to compare their economic aspects. Social sustainability was evaluated using a rating system. The assessments were combined to develop an integrated sustainability and resiliency index. EGM was the most resilient and sustainable alternative for landfill cover systems compared to traditional soil covers. These insights enable an objective comparison of resilience and sustainability, facilitating informed decision-making.