Changes In Surface Morphology Research Articles

Synthesis and clinical efficacy of novel jasmine titania tooth whitening gel on color, surface roughness and morphology

ObjectiveTo analyze the beneficial role of novel jasmine titania tooth whitening gel on the color, surface roughness and morphology of human tooth enamel, concerning age. MethodsGreen dentistry incorporating Jasmine flower extract was used to fabricate titania (titanium oxide) nanoparticles whose physicochemical characteristics were evaluated through X-ray diffraction spectroscopy, scanning electron microscopy, dynamic light scattering spectroscopy, atomic force microscopy and energy dispersive X-ray spectroscopy in order to produce a novel jasmine tooth whitening gel. This whitening gel was applied on maxillary central incisors ranging between 20 and 50 years, which were investigated for color change, surface roughness and morphology. ResultsThe titania nanoparticles depicted 100 % pure anatase phase, 30.3 nm size and a spherical shape with no impurities. The color change (whitening) was found to be maximum in tooth enamel from the youngest age group (20 years), but minimum for the oldest age group (50 years) (p = 0.001). No significant change in surface roughness or morphology of tooth enamel belonging to the youngest age group (20 years) (p = 0.111) and middle age group (p > 0.05) was observed, but it was statistically significant in the teeth belonging to the ultra-middle age group (40 years) and the oldest age group (50 years) (p = 0.001). ConclusionNovel jasmine titania tooth whitening gel containing titania (titanium oxide) nanoparticles prepared by jasmine flower extract revealed potent whitening effects in all the age groups without affecting their surface roughness or morphology. Clinical significanceThe latest trends emerging in aesthetic dentistry show the demand for cosmetic procedures, especially tooth whitening, is enhanced. This novel jasmine titania tooth whitening gel was potent enough to whiten the enamel belonging to different age groups without enhancing the surface roughness or adversely affecting the surface morphology.

Microstructure and surface morphology change of hydrogenated diamond-like carbon coating with gradient Cr and Si under high temperature and high pressure

A series of annealing treatments were designed to investigate the microstructure structure and surface morphology of hydrogenated diamond-like carbon coating with gradient Cr and Si (DCrSi) in different environments (argon & isostatic pressure) at different temperatures (400°C, 500°C, and 600°C). The pressure effect on the stability of DCrSi coatings was deduced from the analysis of the microstructure structure and surface morphology by using scanning electron microscopy (SEM), surface roughness test, and Raman spectroscopy. The experiment results show that no apparent change to the layer structure can be found in the argon annealed and HIPped coatings. Similar to argon annealed coatings, with increasing HIPping temperature, the surface roughness of coatings increases, and the sp3 content of the coatings reduces. The relatively low roughness of the HIPped surfaces compared with the argon annealed ones could be attributed to the delayed transformation from sp3 carbon bonding to sp2 carbon bonding (i.e., graphitization) by high pressure. Compared with Si-free DCr coating, for Si-containing DCrSi coatings, Si bonded with C from broken C-H bonding and C-C bonding to form SiC quasi compound. Adding silicon into DLC can increase the density of the coatings.

Evolution of shale wetting properties under long-term CO2/brine/shale interaction: Implications for CO2 storage in shale reservoirs

In the case of Carbon Geological Storage (CGS), the wettability is one of the main parameters controlling the CO2 injection capacity and CO2 plume movement, which affects the safety of long-term CO2 storage. A full evaluation of this parameter is essential for risk evaluation and storage capacity estimation. The objective of this study was to investigate the wettability changes of shales from the Chang 7 Formation in the Ordos Basin by exposing the samples to ScCO2/brine for 10/20/30/and 60 days. The mineral composition, pore structure, chemical functional groups, and surface morphology changes of the shale were analyzed using x-ray diffractometer (XRD), low-temperature nitrogen adsorption (LN-N2), infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). In addition, the solid-drop method was used to measure the contact angle of shale samples at different times of ScCO2 soaking. The results show that after 60 days of continuous ScCO2 soaking, the shale water contact angle and chemical group peak spectrum generally show an increasing trend, which is caused by the reduction of carbonate and clay mineral content. The prolonged time of ScCO2 soaking weakens the shale's water wettability and reduces the water-locking effect (water has a sealing effect in the pore channel of the reservoir), capillary force, and the height of CO2 sequestration columns, which is favorable for shale gas extraction (a method of extracting natural gas from shale rock by CO2 fracturing), but it may increase the CO2 geological leakage risk. The results have important implications for regulating the change of shale water wettability, and this study can also better provide theoretical references for Carbon Geological Storage programs.

Analisis Metode Anodizing Aluminium dengan Variasi Kuat Arus sebagai Material Velg Kendaraan

Aluminum Alloy 6061 is widely used in various engineering applications, including automotive vehicle wheels. The selection of aluminum alloy wheels involves aspects such as corrosion resistance. To enhance corrosion resistance, there are several methods, one of which is anodizing. Anodizing is a process that involves an electrolytic coating process that transforms the surface of aluminum into aluminum oxide (Al2O3), which the main process of aluminum anodizing requires a solution of sulfuric acid, chromic acid, or a mixture of sulfuric acid and oxalic acid. The sulfuric acid used must be concentrated acid, and acid is an oxidizing substance. The thickness of the oxide is approximately twice the thickness of the lost aluminum. The purpose of this research is to determine the characteristic such as surface roughness values, corrosion rates, and changes in morphology in Aluminum 6061 after undergoing anodizing. In this study, various current strengths were used, namely 0.75 Amperes, 1.5 Amperes, 2.25 Amperes, and 3 Amperes. The highest surface roughness value was obtained at 0.447 μm in the third specimen of the 0.75 Ampere variation, while the lowest was 0.075 μm in the first specimen of the 3 Ampere variation. The highest corrosion rate was observed in the 0.75 Ampere variation, with a rate of 17.724004 mpy, and the lowest was 0.0731653 mpy in the 3 Ampere variation. SEM results show that, in general, Aluminum 6061 tends to have a bright gray color, which is a surface that has been coated by cathode.

Study on the high temperature performance of recycled concrete with manufactured sand

Recycled concrete with manufactured sand (RCM) is a type of recycled concrete that uses manufactured sand as fine aggregate, and there have been limited reports on the investigation of its high temperature performance in the construction industry. This study, starting from two curing regimes, explored the high temperature performance of RCM with water-to-cementitious ratios of 0.32, 0.4, and 0.48. Various physical properties of the samples in each group were tested, including surface morphology changes, mass loss rate, microstructure and composition alterations, as well as fundamental mechanical properties like compressive strength and elastic moduli. The experimental results indicate that RCM specimens exhibit slightly higher compressive strength after 7 d of high-temperature water curing compared to the 30 d standard curing. Furthermore, following high temperature tests ranging from 200 °C to 800 °C, the strength reduction in the specimens is not significantly pronounced when compared to those subjected to standard curing. Utilizing the measured stress-strain curves and existing constitutive models for high temperature behavior of recycled concrete, this study analyzes the influencing factors affecting the performance of RCM under high temperature conditions. The findings provide theoretical support for the practical engineering application of RCM.

Tailoring surface properties of Poly(caprolactone)/Hydroxyapatite scaffolds through aminolysis and multi-walled carbon nanotube coating for bone tissue engineering

In this study, the effects of surface modification on the physicochemical properties, degradation behavior, and cellular responses of poly(caprolactone) (PCL)/hydroxyapatite (HAp) scaffolds using carboxylated multi-walled carbon nanotubes (MWCNTs) were investigated. The scaffolds were prepared using the fused deposition modeling (FDM) technique, followed by aminolysis for 15, 30, and 60 minutes. Subsequently, the scaffolds were immersed in MWCNT solutions with concentrations of 0.1 %, 0.5 %, and 1 % g/mL to achieve the desired coating. Various characterization techniques were employed to evaluate the surface morphology, chemical composition, and structural changes induced by the coating. FESEM images revealed a uniform MWCNT coating on the PCL/HAp scaffolds at an optimal concentration of 0.5 % g/mL, while lower concentrations resulted in incomplete coating and higher concentrations led to MWCNT agglomerations. The MWCNT coating successfully enhanced the conductivity of the scaffolds, with electrical conductivity increasing from near zero for the non-coated PCL/HAp scaffolds to 5 × 10−5 S/m for the MWCNT-coated scaffolds. Additionally, the coating exhibited improved wettability, as demonstrated by decreased water contact angles from 67.71° for non-coated surfaces to 51.50° for the MWCNT-coated surfaces. Furthermore, the in vitro degradation studies showed that HAp in the PCL matrix accelerated the hydrolysis rate, resulting in higher degradation rates for the PCL/HAp scaffolds than pure PCL scaffolds. The MWCNT coating further influenced the degradation behavior, with variations in degradation rates depending on the MWCNT concentration. Cell viability assays using MG-63 cells revealed improved cell viability and adhesion on the MWCNT-coated PCL/HAp scaffolds compared to plain PCL and PCL/HAp scaffolds. The cell viability increased from 84 % for plain PCL and 103 % for PCL/HAp to 109 % for the MWCNT-coated scaffolds. Moreover, FESEM images showed increased cell adhesion on the MWCNT-coated surfaces, with optimal adhesion observed on the scaffolds coated with 0.5 % g/mL MWCNTs. The results of this study highlight the potential of MWCNT coatings to improve the surface properties of PCL/HAp scaffolds, making them excellent choices for bone tissue engineering applications.

Effect of radiotherapy on microhardness and surface morphology of pretreated primary teeth with silver diamine fluoride: an in vitro study

Abstract Background: Children with head and neck cancer undergo radiation therapy, which has proved to be a successful treatment option. One of the common side effect of radiation therapy has been radiation induced caries. This is not as a result of the decreased salivary flow, but rather as a result of the direct impacts of these harmful rays on the enamel of the teeth. Silver diamine fluoride (SDF) is an effective remineralising agent for initial carious lesions and prevents demineralisation of the already deep carious agent. Various studies have also proved its effectiveness in improving the microhardness of the teeth. Hence, the objective of this study was to evaluate whether radiotherapy causes changes in the microhardness and surface morphology of enamel in primary teeth pretreated with SDF. Method: 22 primary teeth samples were divided into two groups with 11 samples in each group. The study group samples were pretreated with SDF and in the control group no pretreatment was done. Both groups were subjected to radiotherapy of 60 Gy radiation for a duration of 30 days. The samples were tested using the Vickers microhardness test and scanning electron microscope (SEM) analysis for surface morphological changes post radiotherapy. Results: It was found that there was a statistically significant difference (p<0.001) in mean microhardness values between the two groups. The mean microhardness of the SDF group (254.07 ± 35.84) was significantly higher that the control group (88.18 ± 6.79). SEM image of enamel of control teeth displayed loss of smooth homogeneous surface and more amorphous structures were seen which was very evident in comparison to the SDF group. Conclusion: Following radiation therapy, SDF application led to greater microhardness of the enamel surface and less morphological alteration in the surface enamel of primary teeth.

Effects of copper and bismuth dopants on PVA/NBT film as an X-ray dosimeter

Low-dose X-rays in the order of milligrays (mGy) are employed in diagnostic radiology. This poses a challenge, considering commercially used dosimeters have limitations in detecting low-dose X-rays. Accordingly, the goal of this research was to fabricate a nitro blue tetrazolium-doped polyvinyl alcohol (PVA/NBT) film dosimeter that could respond to low-dose X-rays while also investigating the effects of introducing copper(II) and bismuth(III) ions on the film's detecting ability. The films were synthesized by the solvent casting method and then exposed to X-ray radiation at doses in the range of 0–2.626 mGy. Optical density and UV–Vis transmittance measurements were carried out to identify changes in the film's optical characteristics brought on by X-ray radiation. In addition, changes in the film's surface morphology and chemical structure were examined by scanning electron microscopy (SEM) and FTIR spectroscopy. According to the results of the optical density measurement, introducing copper(II) ions to the film increased its sensitivity and response linearity. In contrast, the opposite was shown in the case of bismuth(III)-doped films. According to FTIR analysis, film X-ray irradiation caused the PVA to degrade. The development of grain structures on the film surface might be related to the reduction of the copper(II) and bismuth(III) ions. This study discovered that copper(II) ion-doped PVA/NBT film has promising low-dose X-ray detection properties.

Failure analysis of glass fiber and basalt fiber reinforced polymer composites under an extreme environment with high‐temperature, high‐pressure and H2S/CO2 exposure

AbstractFiber‐reinforced polymers composites (FRPs) are widely used in the industrial field, but their failure mechanism in extreme environments is usually unclear. In this work, the effect of high‐temperature, high‐pressure and H2S/CO2 extreme environment, similar to oil and gas field conditions, on raw fibers and unidirectional FRPs was investigated. The results showed that the glass fibers (GFs) suffered extensive degradation with the presence of metal sulfides in the precipitate, whereas basalt fibers (BFs) showed localized degradation. The flexural modulus of glass fiber reinforced polymer composite (GFRP) after degradation decreased by 28.8% compared to 25.6% for the basalt fiber reinforced polymer composite (BFRP). The interlaminar shear strength and flexural strength of the BFRP decreased by 20.3% and 24.7% respectively. In contrast, the GFRP had a reduction of 55.2% in flexural strength after degradation. Finite element method (FEM) analysis showed that the GFRP exhibited severe cohesive interface damage, while the primary failure mode of BFRP remained essentially unchanged with a combination of fiber damage and cohesive interface damage. This study confirms the superior degradation resistance of BF/BFRP over GF/GFRP in the simulated environment and highlights its promising application potential in oil and gas field service.Highlights Filament winding was used to fabricate the GFRP and BFRP. Revealed distinct surface morphology changes in GFs and BFs under simulated oil and gas field conditions. Superior degradation resistance of BFRP over GFRP was found in the extreme environment. Demonstrated superior chemical stability and mechanical properties of BFRP over GFRP. Used FEM to investigate the failure modes of FRPs before and after exposure.

Fabrication of Vascular Grafts Using Poly(ε-Caprolactone) and Collagen-Encapsuled ADSCs for Interposition Implantation of Abdominal Aorta in Rhesus Monkeys.

The production of small-diameter artificial vascular grafts continues to encounter numerous challenges, with concerns regarding the degradation rate and endothelialization being particularly critical. In this study, porous PCL scaffolds were prepared, and PCL vascular grafts were fabricated by 3D bioprinting of collagen materials containing adipose-derived mesenchymal stem cells (ADSCs) on the internal wall of the porous PCL scaffold. The PCL vascular grafts were then implanted in the abdominal aorta of Rhesus monkeys for up to 640 days to analyze the degradation of the scaffolds and regeneration of the aorta. Changes in surface morphology, mechanical properties, crystallization property, and molecular weight of porous PCL revealed a similar degradation process of PCL in PBS at pH 7.4 containing Thermomyces lanuginosus lipase and in situ in the abdominal aorta of rhesus monkeys. The contrast of in vitro and in vivo degradation provided valuable reference data for predicting in vivo degradation based on in vitro enzymatic degradation of PCL for further optimization of PCL vascular graft fabrication. Histological analysis through hematoxylin and eosin (HE) staining and fluorescence immunostaining demonstrated that the PCL vascular grafts successfully induced vascular regeneration in the abdominal aorta over the 640-day period. These findings provided valuable insights into the regeneration processes of the implanted vascular grafts. Overall, this study highlights the significant potential of PCL vascular grafts for the regeneration of small-diameter blood vessels.

Understanding the Relationship between Surface Quality and Chip Morphology under Sustainable Cutting Environments.

Although chip morphology changes according to the machining method and related cutting parameters, chip formation affects the quality of the machined surface. In this context, it is very important to understand the relationship between chip morphology and surface quality, especially in materials that are difficult to machine. In the presented study, the changes in chip morphology, surface morphology, and surface quality criteria (Ra and Rz) that occurred during the milling of precipitation-hardened steel in different cutting environments were analyzed. Milling experiments were carried out in dry, MQL (minimum quantity lubrication), nano-MQL (graphene), nano-MQL (hBN), Cryo, and Cryo-MQL environments using TiAlN-coated inserts and three different cutting speeds and feed rates. While the highest values in terms of Ra and Rz were measured in dry machining, the minimum values were obtained in a nano-MQL (hBN) cutting environment. Due to the lubrication and low friction provided by the MQL cutting environment, chips were formed in thinner segmented forms. This formation reduced the chip curve radius and thus provided a more stable surface morphology. On the other hand, Cryo-ambient gas could not effectively leak into the cutting zone due to the intermittent cutting process, but it increased the brittleness of the chips with the cooling effect and provided a similar surface morphology. The values of minimum Ra and Rz were obtained as 0.304 mm and 1.825 mm, respectively, at a 60 m/min cutting speed and 0.04 mm/rev feed. Consequently, the use of nano-MQL cutting medium is seriously recommended in terms of surface quality in milling operations of difficult-to-machine materials.

A water stable Cu-MOF/GO composite as a persulfate activator for efficient degradation of dye wastewater

Water pollution caused by textile dyes is considered a major and growing issue. To address this challenge, in this research, water-stable Cu-MOFs/GO composite catalysts were produced using the hydrothermal synthesis method as an efficient persulfate (PDS) activator for methyl orange (MO) degradation. We also explored the changes in surface morphology, crystal structure, surface functional groups, and valence states of the materials before and after the introduction of GO by Cu-MOFs. It was shown that Cu-MOFs/GO demonstrates a more stable surface structure, and the unique folded structure of GO provides a better hydrophobic environment for Cu metal cluster hence making MOF easier to grow. The Cu-MOFs/GO-PDS system showed a high activation performance on persulfate in a wide pH range (3–11), meanwhile, was less affected by the presence of natural anions in the environment and more inhibited by natural organic matter citric acid. Furthermore, the Cu-MOFs/GO had excellent stability, reusability and structural integrity, and the removal rate of MO was maintained after five cycles. In terms of oxidation mechanism, in addition to the generation of ·SO4− and OH· radicals, there were also singlet oxygen 1O2 and active Cu(III) in the system, and all of these active substances contributed to the removal of pollutant MO.

Wetting Behavior Driven by Surface Morphology Changes Induced by Picosecond Laser Texturing.

The laser surface texturing (LST) technique has recently been used to enhance adhesion bond strength in various coating applications and to create structures with controlled hydrophobic or superhydrophobic surfaces. The texturing processing parameters can be adjusted to tune the surface's polarity, thereby controlling the ratio between the polar and dispersed components of the surface free energy and determining its hydrophobic character. The aim of this work is to systematically select appropriate laser and scan head parameters for high-quality surface topography of metal-based materials. A correlation between texturing parameters and wetting properties was made in view of several technological applications, i.e., for the proper growth of conformal layers onto laser-textured metal surfaces. Surface analyses, carried out by scanning electron microscopy and profilometry, reveal the presence of periodic microchannels decorated with laser-induced periodic surface structures (LIPSS) in the direction parallel to the microchannels. The water contact angle varies widely from about 20° to 100°, depending on the treated material (titanium, nickel, etc.). Nowadays, reducing the wettability transition time from hydrophilicity to hydrophobicity, while also changing environmental conditions, remains a challenge. Therefore, the characteristics of environmental dust and its influence on the properties of the picosecond laser-textured surface (e.g., chemical bonding of samples) have been studied while monitoring ambient conditions.

Enhanced mechanical performance and damping behavior of CFRP composites through exfoliated MWCNT functionalization

In evaluating high-performance multiwall carbon nanotube (MWCNT) based carbon fiber composites, effective chemical functionalization of fillers for sufficient exfoliation and precise interface interactions with resin matrix are challenging to attain due to significant interlayer cohesive energy and inactive surfaces of composites. Herein, we demonstrate an effective way to produce carbon fiber-reinforced polymer (CFRP) composite with amended interfacial characteristics via incorporation of MWCNT through oxidation followed by silane functionalization with their exfoliation levels (0/48/60/72 h). The surface functional elements, morphological changes, elemental groups, quantitative information, and thermal degradation of silane functionalized MWCNTs were characterized by FESEM/HR-TEM, XRD, UV, and TG-DTA analysis, respectively. The influence of silane functionalized MWCNT reinforcement on CFRP's mechanical properties were examined using tensile, flexural, ILSS, and damping behavior was analyzed through impulse excitation technique (IET). The resulting silane-modified MWCNTs with 60 h oxidation (OAC-60) infused CFRP demonstrated significant enhancement in flexural strength (73.8%), tensile strength (58.2%), interlaminar shear strength (28.5%) compared to pure-CFRP.

Effects of photodegradation performance with PLA‐containing samples on double injection molding

AbstractThe influence of different overlay layers (ABS, PC, and PLA) is investigated on the photodegradation behavior of poly(lactic acid) (PLA)‐containing samples in double injection molding, and PLA/PLA samples serve as the control group. In terms of microstructure, an analysis is conducted on the chemical structure, thermal performance, crystallinity, and molecular weight of the base layer of samples. The carbonyl index and molecular weight of the base layer of PLA/PLA samples decrease rapidly, and the trend of crystallinity change is also fast. Among them, the number of molecular chain scissions decreases to 0.61, and the crystallinity increases to a maximum of 17.93%, which indicates that the photodegradation degree of the base layer of PLA/PLA samples is greater than that of the other two samples. The microscopic surface morphology change of the base layer of three PLA‐containing samples is analyzed. The base layer of PLA/PLA samples becomes rougher after 600 h of UV degradation. Meanwhile, compared with other PLA‐containing samples, the percentage of tensile strength loss of PLA/PLA samples is higher, decreasing by 16.64%. In summary, using acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) materials as overlay layers for double injection molding can mitigate the photodegradation of the base layer of PLA‐containing samples in double injection molding.

Observation of dynamic nanoscale thermal expansion in mirrors and graphene-aided heat dissipation by an advanced chromatic confocal microscopy

In this Letter, dynamic nano-thermal expansion images of reflective mirrors from high-intensity incident laser beams were observed in situ. The inspections are based on rapid 3D surface morphology changes on the reflective surfaces, captured by a Chromatic Confocal Microscope with Nanoscale Sensitivity (CCMNS). Nano-expansions of two types of coatings were studied: the E02 dielectric coating (coating 1) and the graphene-on-E02 complex film (coating 2), both applied to the same fused silica substrate. The superior thermal dissipation properties of coating 2, including enhanced heat dissipation, suppressed wavefront distortion, and its unique negative expansion coefficient, were observed. In addition to studying the effects of graphene coating, the CCMNS demonstrates an accurate and efficient approach for evaluating reflective mirrors. Moreover, the proposed methodology possesses enormous potential across various fields, ranging from estimating photonic elements dealing with high-intensity beams to physical thermal conductivity measurements.

Biocompatibility and Cytotoxicity of Pulp-Capping Materials on DPSCs, With Marker mRNA Expressions

ObjectivesThe present study aimed to (i) investigate biocompatibility and cytotoxicity of pulp capping materials on viability of hDPSCs, (ii) determine angiogenic, odontogenic, and osteogenic marker mRNA expressions, and (iii) observe changes in surface morphology of the hDPSCs using SEM. MethodsImpacted third molars were used to isolate the hDPSCs, which were treated with extract release fluids of the pulp capping materials (Harvard BioCal–Cap, NeoPutty MTA, TheraCal LC, and Dycal). Effects of the capping materials on cell viability were assessed using MTS assay and the apoptotic/necrotic cell ratios and ROS levels from a flow cytometry. Marker expressions (ALP, OCN, Col1A, SPARC (ON) and VEGF) were determined by RT-qPCR. Changes in surface morphology of the hDPSCs were visualized by SEM. ResultsThe MTS assay results at days 1, 3, 5 and 7 indicated that Harvard BioCal–Cap, NeoPutty MTA and TheraCal LC did not adversely affect cell viability when compared to the control group. According to the MTS assay results at day 14, no significant difference was found among Dycal, Harvard BioCal–Cap, NeoPutty MTA and TheraCal LC affecting the cell viability. Dycal was the only capping material that increases the ROS level. High levels of VEGF expression were observed in Harvard BioCal-Cap, TheraCal LC, and NeoPutty MTA. NeoPutty MTA and Dycal up-regulated OCN expression, whereas TheraCal LC up-regulated Col1A and SPARC expression. Only Dycal increased ALP expression. The hDPSCs were visualized in characteristic spindle morphology by SEM due to TheraCal LC and Harvard BioCal–Cap. ConclusionsNeoPutty MTA and Harvard BioCal–Cap showed suitable biocompatibility values, and in particular, these pulp capping materials were observed to support the angiogenic marker. Clinical SignificanceSince it was thought that cytotoxicity and biocompatibility values would contribute significantly to future studies, a new pulp capping material, NeoPutty MTA and Harvard BioCal-Cap, were used in this study.

Exploring the efficacy of various essential oils in chitosan‐based composite biopolymer films for food packaging

AbstractTo ensure food and environmental safety, biodegradable packaging materials from various natural polymers are being used to preserve the high quality of foods and to increase their shelf life in addition to environmental safety in terms of biodegradability. However, these natural polymers have some disadvantages in functionality. There are many ways to improve functionality, one such way is the addition of essential oils. Therefore, this research work was done to investigate the effectiveness of four diverse essential oils (EOs), namely, lemon‐grass oil (LGO), tea‐tree oil (TTO), thyme oil (THO), and basil oil (BO) in chitosan‐based composite films. The chitosan as a biopolymer, polyvinyl alcohol (PVA) as a compatibilizer, and four different essential oils@0.3% were blended to form composite food packaging films. These nanofilms had better mechanical strength, elasticity, and film thickness. Thermal stability and change in the weight of chitosan alone and composite films were determined by thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) was used to analyze the change in film surface morphology. The Fourier transform infrared (FTIR) spectrum of the base polymer exhibits characteristic peaks at 3400 cm−1 indicating the occurrence of hydrogen‐bonded OH groups, and peaks at 1500–1600 cm−1 corresponding to the amide II band and CO stretch of the acetyl group. Whereas TGA results confirmed the thermal stability of PVA and EO blended films compared to chitosan alone films. The biodegradability of antimicrobial chitosan‐based films exhibited around 15%–19% percentage of degradation in PVA blended films whereas chitosan alone degraded up to 32% after 30 days. Water vapor transmission was high in chitosan alone film (1.9%) and 0.25% in PVA/EO blended films displaying enhancement in hydrophobic qualities of the developed films due to change in hydrophobicity by EO addition. The chitosan and PVA alone films were transparent whereas EO blended films exhibited yellow coloration and became less transparent due to the oil droplets dispersion in films. The shelf life of tomato, bread, and paneer was better in lemongrass and tea tree oil‐incorporated films during storage.

Space-weathering induced changes in hydrated silicates: A multi-scale study combining visible/infrared spectroscopy and electron microscopy

Investigating the effects of space-weathering on primitive bodies is paramount in assessing their composition and understanding their history. For this purpose, we conducted 40 keV He and Ar ion-implantation experiments on terrestrial phyllosilicates, the main components of primitive C-class asteroids: two serpentines, and one saponite. We emulated the effects of the solar wind component of space weathering on hydrated surfaces over timescales of 1E3–4 years in the inner solar system. Spectral changes (from 0.35 to 30 μm in wavelength), surface topography variations, and elemental and morphological changes were investigated. In the visible range, we saw darkening for all samples, accompanied by reddening for the serpentine samples and blueing for the saponite. Spectroscopic features such as the silicate stretching and bending modes at 10 and 20 μm respectively, as well as the (M)-OH bending mode at 16 μm, exhibited a peak shift towards longer wavelength (red-shift), band area decrease, and band widening. The surface of Ar-implanted samples appeared polished, while no difference was noticeable for He-implanted samples. Morphological changes in the ion-implanted layers of our samples include abundant vesiculation and lattice amorphization. Mg and O appear to be particularly mobile upon ion implantation. In particular, dehydroxylation was observed for all samples. Changes observed for spectroscopic features do not correlate systematically with variations of the Mg/Fe ratio. They do correlate with oxygen loss via dehydroxylation and crystal lattice disordering and amorphization. Spectral changes in the visible range and for 10 and 20 μm features appear to be mainly due to crystal amorphization. Variation of the hydration feature at 16 μm correlates with both dehydroxylation and lattice amorphization. Compositional variations affect the hydration feature at 2.7 μm more consistently. The effects detected upon ion implantation on the samples in this work support the identification of spectral trends from the remote-sensing data of primitive bodies Ryugu and Bennu as changes induced by space-weathering. Findings are also compatible with laboratory analysis on returned weathered grains from Ryugu.

Surface Roughness Evaluation of Pre- Versus Post-Crystallization Polish of Two High-Strength Silicate Ceramics for Chairside CAD/CAM Technology

This in vitro study evaluated the surface roughness (Sa) of two high-strength silicate ceramics, lithium disilicate IPS e.max CAD, Ivoclar Vivadent (LDS group), and zirconia-reinforced lithium silicate Vita Suprinity, VITA Zahnfabrik (ZLS group). The surface roughness was investigated before and after milling using different polishing systems and timings relative to the final crystallization of the ceramics. Forty-eight samples per group were polished by a single calibrated operator using two polishing systems: Dialite LD (Brasseler) and Lithium Silicate Polishers (Meisinger) for the LDS group and Dialite LD (Brasseler) and Vita Suprinity Polishing Set Technical (VITA Zahnfabrik) for the ZLS group, both pre- and post-crystallization. Surface roughness was measured using a confocal laser microscope (OLS4000 LEXT/Olympus), with scanning electron microscopy (SEM) used to evaluate surface morphological changes. Significant differences in Sa values were found between baseline groups, with ZLS exhibiting lower values. All polishing methods significantly reduced surface roughness compared to baseline (p ≤ 0.05). No significant differences were found in LDS samples when polishing pre- or post-crystallization (p = 0.129), while for ZLS samples, post-crystallization polishing achieved significantly smoother surfaces (p < 0.001). The study concluded that the choice of polishing system and timing did not significantly affect surface roughness for LDS. However, it is recommended that post-crystallization polishing be performed for the optimal smoothness of ZLS. This study aimed to evaluate the post-milling polishing procedures of CAD/CAM high-strength restorations, emphasizing the importance of an optimal surface roughness to prevent issues such as increased risk of abrasion on opposing teeth, enhanced plaque adhesion, and mechanical failures. Investigating these polishing techniques enables clinicians to optimize clinical performance, thereby improving the quality and longevity of high-strength silicate ceramics.