Surface Morphology Measurements Research Articles

Fluidized spanlastics for intranasal brain delivery of lacosamide aiming to control Status Epilepticus: Design, Characterization, Ex-vivo permeation, Radioiodination and In-vivo biodistribution studies

Status Epilepticus (SE) is a neurological condition characterized by anomalous brain activity, causing repetitive seizures lasting for more than 5 min or periods of unusual behavior without returning to a normal level of consciousness between episodes. Chitosan has shown various pharmaceutical benefits, particularly in intranasal administration. In the current manuscript, novel ultra-deformable vesicles (fluidized spanlastics) loaded with lacosamide (LCM), a model anti-epileptic drug, were formulated and compared with their chitosan containing counterparts. The formed vesicles were assessed for their particle size (PS), zeta potential (ZP), entrapment efficiency (EE%) and storage stability. Surface morphology, pH and viscosity measurements, in-vitro release study and release kinetics, and ex-vivo permeation across nasal sheep mucosa were carried out on the optimized formulations. The bio-distribution and pharmacokinetic studies were performed using the radioiodinated-LCM (131I-LCM) utilizing different routes of administration to assess the in-vivo performance of intravenous solutions (IVs), intranasal solutions (INs) and the intranasal administered optimized formula (INFS). LCM-vesicles showed PS ranging from 109.90 to 418.4 nm, negative ZP values ranging from −28.00 to −48.30 mV in case of regular vesicles and shifted to +16.70 to +18.72 mV in case of chitosan coated vesicles, high EE% values having a range of 65.76–97.25 % and good storage stability properties. The optimized formulation showed spherical shape and enhanced ex-vivo permeation approximately 4-fold higher compared to LCM solution. The results of the in-vivo study demonstrated that the brain/blood ratio (B/B) of INs was 3.3-fold higher than IVs and INs of 131I-LCM in the first 5 min. Accordingly, the prepared system has been shown to possess a promising potential for brain diagnosis and/or therapy.

Measurement of 3D joint surface morphology and estimation for shear mechanical behavior: A theoretical model and experimental investigation

The majority of rock engineering instabilities are primarily due to shear slips and failures on the joint surfaces, and the measurement of joint surface morphology is crucial for shear strength evaluation. In this study, the high-precision 3D laser scanner was first used to characterize and digitally reconstruct the surface morphology of various joints. The evaluation method of joint surface roughness was modified according to the 2D profile data and shear direction. Then, the effects of normal stress and initial joint roughness coefficient on the shear mechanical behavior were investigated by experimental method. The damage evolution characteristics and failure mechanism of the joint surface are analyzed by acoustic emission monitoring and image binarization calculations. The research results indicate that as the normal stress and initial joint roughness coefficient increase, the peak shear stress and shear displacement, residual strength, and cumulative AE counts of rock joints display an increasing trend. Based on the evolution of mechanical parameters, a new mechanical model of rock joints to predict shear strength and deformation was developed, which was validated by comparing the theoretical prediction curves with test results. A good concordance was achieved between the shear test and theoretical results, indicating that the developed model can effectively predict the shear strength and deformation of joint surfaces under different normal stress and roughness. This research results are expected to provide a valuable guidance for early warning and evaluation of geological disasters.

Thiol functionalized porous carbon nanospheres: Synthesis, characterization, experimental and DFT studies

Thiol-modified nanoporous structured frameworks prove to be efficient trapping agents for eliminating mercury (Hg(II)) ions from water. In this work, we synthesized porous carbon nanospheres and chemically functionalized them with l-cysteine molecules following a Fischer esterification reaction and investigate them for selective Hg(II) separation. The material was characterized for functional group analysis, surface morphology and water contact angle measurement by using several spectroscopic and optical techniques likely FT-IR, XPS, SEM, TEM and goniometer analyzer. The column packed material shows selective extraction of trace Hg(II) ions at wide pH range. The selectivity of Hg(II) is primarily attributed to Lewis soft–soft acid–base chelation, wherein Hg(II) forms complexes with the thiol functionalities of the adsorbent. Density functional theory (DFT) calculations suggest that the fast energetically favorable R–SH–Hg–OR complex formed over R–S–Hg–NH–R bidentate complexes, thereby promoting selective extraction of Hg(II). The preconcentration limit for Hg(II) achieved at pH 6 was found to be 0.37 ppb. The instrumental detection limit (3 s/m) obtained after preconcentration of 11 blank runs is found to be 0.04 ppb with the relative standard deviation of 3.68 %. The accuracy of the proposed column method was validated by analyzing several real samples with enrichment factor of 100 and after spiking with varying amount of analyte. The method shows a good recovery of 97–100 % of spiked amount with RSD <5 %.

Flame retardancy of cotton and cotton/polyester fabrics treated by coating with polymer blends containing aluminum and phosphorus metals under the effect of gamma irradiation

The main objective is to impart flame retardancy finishing to cotton and cotton/polyester fabrics. In this process, the fabrics were first treated by coating with poly(vinyl alcohol) (PVA)/plasticized starch (PLST) blends and then exposed to gamma irradiation. The treated fabrics were then loaded with aluminum sulphate [Al2(SO4)3] and monosodium dihydrophosphate (MSDP). The treated fabrics were characterized by the measurements of water absorption, crease recovery, surface morphology and tensile mechanical. Moreover, thermal stability of the treated fabrics was investigated by thermogravimetric analysis (TGA). The thermal stability was further investigated by determining the activation energy by two different methods based on Broido and the Horowitz–Metzger approximation equations. The results showed that the chemical and physical properties of the treated fabrics with PVA/PLST/metal composites were significantly improved. The flammability test in terms of time to catch fire (TF), time after glowing (TG) and weight left (WL) showed that the treated fabric and loaded with [Al2(SO4)3] and MSDP metals displayed improved flammability than untreated fabrics. In addition, the durability of the flame retardancy finished fabrics was evaluated by measuring the limiting oxygen index (LOI) after repeated washing cycles according a standard testing method. The results of durability test indicated that the fabrics treated with composites based on both [Al2(SO4)3] or MSDP metals proved to satisfy the flame retardancy with minimum weight lose percent.

Rheological Investigation of Highly Filled Copper(II) Oxide Nanosuspensions to Optimize Precursor Particle Content in Reductive Laser-Sintering

In this article, the particle concentration of finely dispersed copper(II) oxide nanosuspensions as precursors for reductive laser sintering (RLS) is optimized on the basis of rheological investigations. For this metallization process, a smooth, homogeneous and defect-free precursor layer is a prerequisite for adherent and reproducible copper structures. The knowledge of the rheological properties of an ink is crucial for the selection of a suitable coating technology as well as for the adjustment of the ink formulation. Different dilutions of the nanosuspension were examined for their rheological behavior by recording flow curves. A strong shear thinning behavior was found and the viscosity decreases exponentially with increasing dilution. The viscoelastic behavior was investigated by a simulated doctor blade coating process using three-interval thixotropy tests. An overshoot in viscosity is observed, which decreases with increasing thinning of the precursor. As a comparison to these results, doctor blade coating of planar glass and polymer substrates was performed to prepare precursor layers for reductive laser sintering. Surface morphology measurements of the resulting coatings using laser scanning microscopy and rheological tests show that homogeneous precursor layers with constant thickness can be produced at a particle–solvent ratio of 1.33. A too-high particle content results in an irregular coating layer with deep grooves and a peak-to-valley height Sz of up to 7.8 μm. Precise dilution control allows the fabrication of smooth surfaces with a Sz down to 1.5 μm.

Coupling Michelson-like lateral shear interferometric microscopy with self-referencing numerical phase calibration for quantitative measurement of 3D surface morphology of biological cells

A Michelson interferometer is commonly used for evaluating the morphology of a cell. However, the interference imaging with reference and object beams is easily affected by external vibrations and environmental disturbances, leading to unstable interference patterns. In this paper, the three-dimensional surface morphology of the biological cell is evaluated by a new quantitative phase imaging method, which couples Michelson-like lateral shear interferometric microscopy with self-referencing numerical phase calibration. The Michelson-like lateral shear interferometric microscopy is constructed by replacing the two plane mirrors of the traditional Michelson interferometer with two common right-angle prisms and generates interference fringe patterns. The lateral shear is created and freely adjustable by simply translating/or rotating one right-angle prism. To calculate the phase information of the biological cells quantitatively, the classical Fourier transform method is used to process the recorded interferogram, and then the self-referencing numerical phase calibration method is utilized for acquiring accurate phase information. Successfully achieving quantitative phase imaging of a cell verifies the feasibility and practicability of the proposed method.

Comparing industrial and analytical kraft lignins as biobased UV-protective additives in coatings

Lignin as the second most abundant biopolymer on Earth has the potential to become the alternative to petroleum-derived materials. It exhibits excellent UV absorption ability due to its aromatic structure and the presence of numerous phenolic, ketone, and intramolecular hydrogen bonds. Due to its complex nature, it is important to investigate its properties which is a very important step towards the valorization of lignin. Revealing its structural complexity allows for a better examination of its influence on the properties of the final lignin-based materials. In our research, we used two different kraft lignins: commercial analytical kraft lignin (AL) and industrial LignoBoost kraft lignin (KL) as UV-protect additives in BPA(Bisphenol A)-free polymer coatings based on diurethane dimethacrylate (DIUR). The maximum addition of KL and AL was 2 wt%. Both lignin samples were characterized in detail (composition analysis, ash content, molar mass and polydispersity, surface morphology, thermal properties, and quantitative measurement of hydroxyl group content). We investigated the influence of lignins on the textural and thermal properties of the coatings. Finally, we studied the application of lignin as a value-added UV-protective component by UV-Vis electronic absorption spectroscopy. KL with a higher purity and lower number of aliphatic OH had a better dispersion in the polymer matrix than AL lignin which had more agglomeration in the polymer matrix. The better dispersion resulted in producing a smoother surface in the coatings made from KL. Finally, a noticeable and significant impact of KL additive on the photoprotective properties of the coating material was demonstrated. These results showed a potential application and opportunity in the valorization of available industrial lignins toward sustainable and value-added products.

Photocatalysis and irradiative TL defect center analysis studies of Cu2+ ionic ZnO nano lattice

The objective of the study is to create a series of ZnO nano powders doped with CuO using sol–gel technology in order to look into their photocatalytic activity for the photodegradation and cleaning process. XRD, BET surface area, surface morphology, chemical analysis, and FT-IR measurements have all been used to look at the nano powders' structure from this point of view. The results suggest that the materials were made at the nanoscale level, and their hexagonal shape makes them good as catalytic nano resources. Photoluminescence and UV–visible diffusion reflection spectroscopy were also used to test the nano powders. The results show that the nano powders that were made are visually active. To find out how photocatalytic the nanoparticles are, they were used to break down CR (10 ppm) and MV (10 ppm) dyes when exposed to light. The nano powder with 1.0 mol% of CuO doped ZnO nanoparticles had the highest photocatalytic efficiency (86 %). It had a band gap energy of 3.15 eV and reacted with both dyes for 90 min. Researchers looked at radical scavengers and the effect of catalyst dose on how well they broke down substances. The reaction that broke down had pseudo-first-order kinetics, and the rate of the reaction was four times faster when 1.0 mol% Cu was added to the ZnO catalyst. The degradation efficiency only dropped by 1 % after three rounds of the process. Because of this, the 1.0 mol% Cu-ZnO was used as a photocatalyst that broke down textile dyes well and had a lot of promise to be used again. The samples were also checked for thermoluminescence while they were exposed to 25 kGy of gamma radiation. Samples were tested for their trap depth characteristics, indicating the test samples' potential for TL activity.

In situ characterization of optical micro/nano fibers using scattering loss analysis

We experimentally demonstrate the in situ characterization of optical micro/nano fibers (MNFs). The MNF (test fiber, TF) is positioned on a microfiber (probe fiber, PF) and simulated for the scattering loss at various PF and TF diameters. The TF is fabricated using chemical etching technique. The PF is a conventional single-mode fiber with an outer diameter of 125 μm. We measure the scattering loss along the TF axis at various positions i.e., diameters by mounting it on the PF. The diameter profile of the TF is inferred from the measured scattering loss and correlated with its surface morphology measurement. This work demonstrates an effective, low-cost, and non-destructive method for in situ characterization of fabricated MNFs. It can detect and determine the irregularities on the surface of OMNFs. It can also be used to quantify the local evanescent field. Detecting such local points can improve studies that are carried out using these fields in various sensing and related study domains. It is simple to implement and can be accessed by all domains of researchers.

Interlayer bonding improvement of PEEK and CF-PEEK composites with laser-assisted fused deposition modeling

Fused deposition modeling (FDM) is a cost-effective additive manufacturing technique used to fabricate industrial-grade products with intricate designs using high-performance engineering plastics like Polyetheretherketone (PEEK) and their carbon fiber (CF)-reinforced composites. However, the inherent weak interlayer bonding in the FDM results in anisotropic properties, limiting the mechanical strength and hindering widespread applications. In this study, a layer-wise, in-process laser treatment is proposed to enhance the interlayer bonding in the FDM process of both PEEK and CF-PEEK composites. The laser-assisted process selectively treats previously deposited layers, significantly improving the interlayer bonding by enlarging surface contact, reducing voids, and increasing crystallinity. To validate the effectiveness of this method, tensile and bending tests are conducted, accompanied by observations of surface morphology, roughness analysis, and crystallinity measurements. The results demonstrate significant enhancements with over a 20 % increase in tensile strength and 10–20 % increase in bending strength for both materials. This hybrid additive manufacturing method revolutionizes the mechanical properties of printed parts and opens up new possibilities for processing PEEK and CF-PEEK composites.

Effect of laser shock peening on the dissolution of precipitates and pitting corrosion of AA6061-T6 with different original surface roughness

The effect of laser shock peening (LSP) on the electrochemical corrosion behavior of AA6061-T6 with different original surface roughness in the 3.5 wt% NaCl solution was investigated by surface morphology measurement, microstructural characterization, and electrochemical corrosion testing. The results show that LSP improves passivation current density by 76.6%− 78.2% and polarization resistance by 287.2%− 288.9%, but does not change the influence law of the surface roughness on the corrosion behavior of aluminum alloy. LSP promoted the complete dissolution of nano-sized Al8Fe2Si particles, generation of ultrafine grains, and local dissolution of micron-sized Al8Fe2Si particles, contributing to the improved corrosion resistance.

Experimental and numerical investigation on mechanical and fatigue performance of corroded Q690D high-strength steel

As a prevalent environmental factor in the service process of steel structures, corrosion have a significant impact on the mechanical and fatigue properties of steel, thus deteriorating service safety. In this article, focused on corroded Q690D high-strength steel, experimental and numerical investigations have been performed. Electrolytic accelerated corrosion experiments were conducted, and 3D surface morphology measurements were employed to analyse the surface properties of specimens with various corrosion degrees. Mechanical and high-cycle fatigue tests were carried out on the corroded specimens, then degradation models between the mechanical behaviours and corrosion characteristics were established. Furthermore, the fatigue damage evolution model of Q690D high-strength steel was calibrated based on continuum damage mechanisms (CDM), and numerical simulations of the corroded specimen corresponding to the monotonic tensile tests and high cycle fatigue tests were conducted. The results show that with the increase of corrosion degree, the elastic modulus, yield stress, and tensile stress would decrease, and the fatigue performance would deteriorate. Corrosion has a greater effect on the fatigue life of long-life range and the slopes of the S-N curves after corrosion are more uniform. With the CDM parameters of non-corroded Q690D and the numerical model with consideration of surface roughness, the fatigue life of corroded Q690D could be well simulated.

Identification of tool wear and surface morphology measurements in sustainable milling of Al 6082 hybrid metal matrix composite

Aluminium hybrid metal matrix composites have significantly increased in many advanced applications owing to their unique properties. However, these hybrid composites are difficult to machine because of hard reinforcements in the matrix. After identifying the optimum cutting conditions, it's crucial to identify the tool wear mechanisms to keep surface roughness within the desired range, especially with hybrid composites. Hence, the present work mainly focuses on identifying the wear mechanism of PVD-coated TiAlN cutting tool inserts during the end milling of Al 6082 hybrid metal matrix composites. MQL, CO2, and a combination of MQL + CO2 cooling conditions were employed over the cutting zone to decrease tool wear. In the context of 300 mm of cutting length, employing CO2, MQL, and MQL + CO2 conditions led to a significant reduction in tool wear by 34.5 %, 50.1 %, and 74.7 %, respectively, compared to dry cutting. The results showed that the MQL + CO2 condition produced better results than the other cooling conditions, improving tool life and surface quality.

A New Measure of Posterior Morphology in Sagittal Craniosynostosis: The Occipital Bullet Index

Introduction: Sagittal craniosynostosis (SC) is associated with scaphocephaly, an elongated narrow head shape. Assessment of regional severity in the scaphocephalic head is limited by the use of serial computed tomographic (CT) imaging or complex computer programing. Three-dimensional measurements of cranial surface morphology provide a radiation-free alternative for assessing cranial shape. This study describes the creation of an occipital bulleting index (OBI), a novel tool using surface morphology to assess the regional severity in patients with SC. Methods: Surface imaging from CT scans or 3D photographs of 360 individuals with SC and 221 normocephalic individuals were compared to identify differences in morphology. Cartesian grids were created on each individual’s surface mesh using equidistant axial and sagittal planes. Area under the curve (AUC) analyses were performed to identify trends in regional morphology and create measures capturing population differences. Results: The largest differences were located in the medial regions posteriorly. Using these population trends, a measure was created to maximize AUC. The OBI has an AUC of 0.72 with a sensitivity of 74% and a specificity of 61%. When the frontal bossing index is applied in tandem, the two have a sensitivity of 94.7% and a specificity of 93.1%. Correlation between the two scores in individuals with SC was found to be negligible with an intraclass correlation coefficient of 0.018. Severity was found to be independent of age under 24 months, sex, and imaging modality. Conclusions: This index creates a tool for differentiating control head shapes from those with SC and has the potential to allow for objective evaluation of the regional severity, outcomes of different surgical techniques, and tracking shape changes in individuals over time, without the need for radiation.

Characterization method for electric arc erosion based on the in-situ measurement of electrode surface morphology

The electrical arc significantly influences the surface morphology and the performance of electrode. There has been ever increasing demand for the characterization method of arc erosion. In this work, an in-situ test rig has been described that makes it possible to measure the surface height point cloud data and the microscopic images consecutively during arc erosion cycling. Novel processing algorithms considering the eroded electrode morphology are proposed for characteristic parameters calculation including arc erosion volume, electrode gap and contact area. It has been observed that the inner layer metals of electrode are heated and ejected to the surface after arcing, which form higher bulges with pores. And the electrode gap decreases under higher arc erosion volume. Moreover, in the electrical endurance experiment, the change trends of contact area correlate well with the measured resistance. Based on the collected sensitive parameters, the cumulative arc erosion on the electrode surface is characterized.

Morphology measurements by AFM tapping without causing surface damage: A phase shift characterization

The morphology measurement of a surface can be done by using an atomic force microscope (AFM). However, it is difficult to ensure that the measurement does not introduce any damage to the sample surface. This paper proposes that phase shift, the phase change between the original surface and scanned area, can provide a characteristic signal of the tip-surface interaction. On a poly (methyl methacrylate) thin film, the present investigation explored the relationship between phase shift and nondestructive surface morphology measurement under the tapping mode of an AFM. The study showed that when the drive amplitude was doubled, the phase shift reached from 0.47° to 1.85°. Under this condition, wrinkles became observable. With the tip radius in the range of 15–20 nm, no phase shift appeared between a scanned area and the original surface after multiple measurements. In this case, the tip-surface energy dissipation was in the range of 10–35 eV, showing a nondestructive interaction of the surface with the AFM tip. When the tip radius was about 55 nm, under the same tip excitation parameters, the energy dissipation per tap varied from 60 to 110 eV, and a phase shift occurred in the range of 0.02–0.64°, while the surface plastic deformation was still extremely minor after multiple tip scanning. A higher phase shift was occurred on the softer surface attributed to multiple scanning under tapping mode. The study found that the phase shift characteristics was a more sensible measure to signify the transition from a nondestructive to a destructive surface morphology measurement by using the tapping mode of an AFM.

Electrochemical Study on Corrosion Damage of 7B04 Aluminum Alloy/Anodic Film/Epoxy Coating System in a Simulated Marine Atmospheric Environment

This paper investigates the electrochemical characteristics of the 7B04 aluminum alloy/anodic film/epoxy coating system in a simulated marine atmosphere using electrochemical techniques and surface morphology measurements. The coating system underwent a periodic immersion test for 480 h to simulate the harsh service conditions in a marine environment. Three equivalent circuit models were proposed based on the analysis of the electrochemical failure mechanism of the coating system. Akaike information criterion and Bayesian information criterion were used to selectively choose models for different degradation stages of the coating system, revealing its electrochemical degradation characteristics. Two-stage aging kinetics and gamma models were proposed to describe the time-varying processes of electrochemical low-frequency impedance and corrosion trend, respectively. Ultimately, low-frequency impedance is identified as the most effective and rapid evaluation index for coating performance due to its strong correlation with corrosion trends. The aforementioned models and index provide a foundation for accurately identifying corrosion stages and effectively predicting the corrosion process.

Enhanced effect of a novel bioactive glass-ceramic for dental application.

Dental caries is the most common chronic disease in humans, caused by the acid produced by the microflora in the mouth that dissolves the enamel minerals. Bioactive glass (BAG) has been used in various clinical applications due to its unique bioactive properties, such as bone graft substitutes and dental restorative composites. In this study, we introduce a novel bioactive glass-ceramic (NBGC) prepared through a sol-gel process under a water-free condition. The anti-demineralization and remineralization effects of NBGC were evaluated by comparing the measurements of bovine enamel surface morphology, surface roughness, surface micro-hardness, enamel elements, and mineral content before and after related treatments with a commercial BAG. The antibacterial effect was characterized by minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Results showed that NBGC had greater acid resistance and remineralization potential compared to commercial BAG. The fast formation of a hydroxy carbonate apatite (HCA) layer suggests efficient bioactivity. In addition to its antibacterial properties, NBGC shows promise as an ingredient in oral care products that can prevent demineralization and restore enamel.

Spatiotemporal patterns of the impact of surface roughness and morphology on urban heat island

As important determinants of urban thermal environment, surface roughness and morphology have been extensively studied for sustainable urban development. In this study, we quantify the effect of urban roughness and morphology on the surface urban heat island (SUHI) intensity and its spatiotemporal patterns, over seventeen major cities in six urban agglomerations of China. We employ multisource dataset and derive multiple measures, representative of the roughness and horizontal/vertical indicators of urban morphology. The results show that the correlation between the SUHI intensity and urban morphological indices is significantly strengthened with the heat island intensity, manifested by the contrasting Pearson's r in summer (r = 0.59 ± 0.13) and winter (0.11 ± 0.35). In general, the impact assessed using different measures of surface morphology is consistent on the SUHI intensity, while the one-dimensional (1D) roughness emerges as an adequate index not inferior to more complex morphological parameters. Our study also shows that the impact of urban morphology varies in different geographic and climatic regions, as well as with different urban management, which highlights the importance of locality and site-specific design in implementing effective urban heat mitigation strategies.

Quantitative study on surface porosity and roughness parameters of mineral and organic admixtures based on multi-scale characterisation techniques

Studying surface porosity and surface roughness of mineral and organic admixtures is vital in cement-based applications as these characteristics play a significant role in the behaviour of cement-based composites. Aiming to enhance the characteristics of coconut shell ash (CSA), gum Arabic (GA), cassava starch (CS), rice husk ash (RHA) and burnt clay powder (BCP) including their influence on cement-based composites, the surface porosity and surface roughness characteristics were comprehensively explored using scanning electron microscopy (SEM) under scale of 100 µm and Gwyddion. The surface morphological measurements, surface porosity and surface roughness of the specimens were respectively assessed using parameters such as skewness (Rsk), Kurtosis coefficient (Rku), roughness average (Ra), root mean square roughness (Rq), waviness average (Wa), root mean square waviness (Wq) and plane porosity. The roughness average values were noticed to range from 19 nm to 77 nm whilst the root mean square roughness values were found to vary from 27 nm to 107 nm. The waviness average and root mean square waviness values of specimens ranged from 26–132 nm and 34–157 nm respectively. The skewness values were observed to range from −0.18–0.72 while Kurtosis coefficient values ranged from 3 to 12. The comparisons in plane porosity quantification findings obtained using the implemented algorithms illustrated that the plane porosity values from threshold method were higher than those from segmentation method. The findings from this study extend characterisation of mineral and organic admixtures and subsequently guide management practices of waste materials through utilisation of mineral and organic admixtures in cement-based composites.