Changes In Surface Morphology Research Articles

Influence of IDS and SDS compound ratio on pore structure and wettability of bituminous coal and anthracite: Experimental and simulation discussion

The pore and wetting characteristics of bituminous coal and anthracite treated with different proportions of tetrasodium iminodisuccinate (IDS) and sodium dodecyl sulfate (SDS) were measured. The pore structure characteristics of the coal were studied via low-temperature nitrogen adsorption analysis and the Frenkel-Halsey-Hill fractal theory. Zeta potential measurements were conducted to quantitatively analyze the degree of aggregation or dispersion of coal particles dissolved in solution. Changes in the coal surface morphology were observed and analyzed by scanning electron microscopy (SEM). The results show that when the ratio of IDS:SDS is 1:3, the specific surface area (SSA) values of bituminous coal and anthracite are the lowest. The composite reagent has a greater effect on improving the pore structure of anthracite than bituminous coal. Compared with bituminous coal, anthracite has better pore connectivity and a wider pore network. The absolute zeta potentials of bituminous coal and anthracite reach the maximum at an IDS:SDS ratio of 1:3, with values of 91.08 mV and 91.35 mV, respectively. The electrostatic potential distributions of the molecules show that the advantages of the electrostatic potential difference with water molecules enable IDS and SDS molecules to effectively attract water molecules and form hydrogen bonds, thus revealing the optimization mechanism of coal wettability.

Synergistic Antifungal Activity of Dialdehyde Chitosan Loaded with Copper Metal‐Organic Framework (Cu‐MOF)

AbstractFungal resistance and the environmental degradation posed by conventional fungicides necessitate the need to develop new antifungal agents that can inhibit fungal growth. This study sought to prepare biofungicides by leveraging on the antifungal activity of copper‐metal organic framework (Cu‐MOF) and dialdehyde chitosan (Cs) isolated from black soldier flies (BSF). Cs were oxidized using potassium periodate to obtain dialdehyde Cs (OCs) and thereafter, Cu‐MOF was loaded resulting in Cu‐MOF‐OCs. Fourier Transform Infrared spectrophotometer (FT‐IR) and powder X‐ray diffraction (XRD) confirmed the presence of carbonyl functional groups in OCs and sharp intense peaks associated with Cu that interacted. The changes in surface morphology and the presence of Cu in the MOFs as obtained with Scanning Electron Microscope‐ Energy Dispersive X‐ray (SEM‐EDX), indicated the successful loading of Cu‐MOF on the oxidized Cs. Thermogravimetric analysis (TGA) showed a loss of approximately 31.51 % of the loaded OCs and 40.72 % framework around ∼200 to ∼300 °C and ∼410 to ∼475 °C respectively. The antifungal activity of OCs, Cu‐MOF, and Cu‐MOF‐OCs against Aspergillus brasiliensis and Candida albicans was performed using the plate count method and the results suggested that MOF modulated the antifungal activity exerted by the OCs.

Effect of Electrolytic Plasma Polishing on Surface Properties of Titanium Alloy

Effect of Electrolytic Plasma Polishing on Surface Properties of Titanium Alloy

Severe microplastic pollution risks in urban freshwater system post-landfill fire: A case study from Brahmapuram, India

To investigate the escalating issue of microplastic (MP), pollution in urban water bodies, this study focuses on the aftermath of the Brahmapuram landfill fire in Kochi, India, analyzing its impact on MP concentrations in nearby freshwater system. The study conducted sampling sessions at the landfill site immediately before and after the fire. Post-fire, findings demonstrated a substantial increase in MP concentrations in surface waters, with levels rising from an average 25793.33 to 44863.33 particles/m³, featuring a notable presence of larger, predominantly black MPs. Sediment samples showed no significant change in MP count, but there was a significant increase in mass concentration. SEM/EDS analysis revealed changes in surface morphology and elemental composition, suggesting thermal degradation. Risk assessment using the Microplastic Pollution Index (MPI) and Risk Quotient (RQ) methods indicated heightened MP pollution risk in surface water post-fire. Hierarchical cluster analysis revealed the landfill's proximity as a significant factor influencing MP characteristics in the aquatic system. The study highlights the escalated challenge of MP pollution in urban water bodies following environmental disasters like landfill fires, underscoring the urgent need for policy and environmental management strategies.

The Cd resistant mechanism of Proteus mirabilis Ch8 through immobilizing and detoxifying

Cadmium (Cd) pollution is a serious global environmental problem, which requires a global concern and practical solutions. Microbial remediation has received widespread attention owing to advantages, such as environmental friendliness and soil amelioration. However, Cd toxicity also severely deteriorates the remediation performance of functional microorganisms. Analyzing the mechanism of bacterial resistance to Cd stress will be beneficial for the application of Cd remediation. In this study, the bacteria strain, up to 1400 mg/L Cd resistance, was employed and identified as Proteus mirabilis Ch8 (Ch8) through whole genome sequence analyses. The results indicated that the multiple pathways of immobilizing and detoxifying Cd maintained the growth of Ch8 under Cd stress, which also possessed high Cd extracellular adsorption. Firstly, the changes in surface morphology and functional groups of Ch8 cells were observed under different Cd conditions through SEM-EDS and FTIR analyses. Under 100 mg/L Cd, Ch8 cells exhibited aggregation and less flagella; the Cd biosorption of Ch8 was predominately by secreting exopolysaccharides (EPS) and no significant change of functional groups. Under 500 mg/L Cd, Ch8 were present irregular polymers on the cell surface, some cells with wrapping around; the Cd biosorption capacity exhibited outstanding effects (38.80 mg/g), which was mainly immobilizing Cd by secreting and interacting with EPS. Then, Ch8 also significantly enhanced the antioxidant enzyme activity and the antioxidant substance content under different Cd conditions. The activities of SOD and CAT, GSH content of Ch8 under 500 mg/L Cd were significantly increased by 245.47%, 179.52%, and 241.81%, compared to normal condition. Additionally, Ch8 significantly induced the expression of Acr A and Tol C (the resistance-nodulation-division (RND) efflux pump), and some antioxidant genes (SodB, SodC, and Tpx) to reduce Cd damage. In particular, the markedly higher expression levels of SodB under Cd stress. The mechanism of Ch8 lays a foundation for its application in solving soil remediation.

Enhancing Carbon Fiber Fabrics with ALD AlxOy Coatings: An Investigation of Thickness Effects on Weight, Morphology, Coloration, and Thermal Properties

This study explores the impact of non-stoichiometric aluminum oxide (AlxOy) coatings applied via thermal atomic layer deposition (ALD) on carbon fiber fabrics (CFFs), emphasizing volume per cycle, FESEM analyses, color transitions, and thermal stability enhancements. Using trimethylaluminum and water at 100 °C, AlxOy was deposited across a range of 1000 to 5000 ALD cycles, with film thicknesses extending up to 500 nm. This notable increase in the volume of material deposited per cycle was observed for the 3D CFFs, highlighting ALD’s capability to coat complex structures effectively. FESEM analyses revealed the morphological evolution of CFF surfaces post-coating, showing a transition from individual grains to a dense, continuous layer as ALD cycles increased. This morphological transformation led to significant color shifts from green to red to blue, attributed to structural coloration effects arising from variations in film thickness and surface morphology. Thermogravimetric analyses (TGA and dTG) indicated that the AlxOy coatings enhanced the thermal stability of CFFs, with a postponement in degradation onset observed in samples subjected to more ALD cycles. In essence, this research highlights the nuanced relationship between ALD processing parameters and their collective influence on both the aesthetic and functional properties of CFFs. This study illustrates ALD’s potential in customizing CFFs for applications requiring specific color and thermal resilience, balancing the discussion between the surface morphological changes and their implications for color and thermal behavior.

Effects of surface modification of sucrose particles on chocolate morphology and fat bloom during storage

In this study, a new bloom-reducing approach, modifying the surface of crystalline sugar was introduced and confirmed through two methods (circularity and Casson viscosity). Targeting the effects of sucrose shape on bloom, model chocolates were formulated with 2 sucrose surfaces (before and after modification) at 3 sucrose volume fractions (0.15, 0.50, and 0.75) in the nonfat particle phase. Bloom was evaluated by changes in whiteness index (ΔWI) and white area percentage (WA%), accompanied by polymorphic transition evaluations. Surface morphology during storage was also evaluated by scanning electron microscopy (SEM) to quantify surface roughness and porosity. Bloom and SEM results both showed similar trends: smoothing sucrose particle surface as well as reducing sucrose fraction volume significantly reduced bloom and surface morphological (roughness and porosity) change, indicating that sucrose surface modification may have a significant impact on the particulate microstructures in chocolate thus impeding bloom formation during storage.

Effect of high temperature on the mixed mode I-II fracture characteristics of hot-dry rock

To investigate the variation law of rock fracture characteristics with temperature in hot-dry reservoirs, the pure mode I, pure mode II and mixed mode I-II loading experiments were carried out on sandstone and granite at room temperature and after high-temperature (100 °C, 300 °C, 500 °C and 700 °C) treatment by using the central cracked Brazilian disk (CCBD) specimen. The changes of parameters such as failure load, fracture toughness and fracture envelope with temperature were discussed, and the changes of rock mineral composition and fracture surface morphology were analyzed by X-ray diffractometer (XRD) and scanning electron microscope (SEM), respectively. The results showed that the influence of temperature on the fracture characteristics of sandstone and granite presents different evolution laws.With the increase of temperature, the failure modes of sandstone and granite all change from brittle failure to ductile failure, but the critical temperature of the transition is different. Granite shows obvious ductile failure characteristics at 500 °C, while sandstone shows slight ductile failure characteristics at 500 °C.The failure load and fracture toughness of sandstone increase first and then decrease with the increase of temperature, which indicates that within a certain range, the temperature has a toughening effect on sandstone, and can improve its failure resistance. However, the failure load and fracture toughness of granite always decrease with the increase of temperature, which indicates that the temperature only has a deteriorating effect on granite. In the range of 100 °C to 500 °C, the temperature enhances (sandstone) or weakens (granite) the mode I fracture toughness of rocks more than it enhances or weakens the mode II fracture toughness. However, when the temperature is 700 °C, the temperature weakens the mode II fracture toughness more than the mode I fracture toughness. The area enclosed by the fracture envelope of sandstone first increases and then decreases with the increase of temperature, while the area enclosed by the fracture envelope of granite decreases with the increase of temperature. As the temperature increases, the tortuosity of the crack paths in sandstone and granite increases, the cross-section morphology becomes rougher, and the internal fissures and fragmentation increase.

Physiochemical and Electrochemical Properties of a Heat-Treated Electrode for All-Iron Redox Flow Batteries.

Iron redox flow batteries (IRFBs) are cost-efficient RFBs that have the potential to develop low-cost grid energy storage. Electrode kinetics are pivotal in defining the cycle life and energy efficiency of the battery. In this study, graphite felt (GF) is heat-treated at 400, 500 and 600 °C, and its physicochemical and electrochemical properties are studied using XPS, FESEM, Raman and cyclic voltammetry. Surface morphology and structural changes suggest that GF heat-treated at 500 °C for 6 h exhibits acceptable thermal stability while accessing the benefits of heat treatment. Specific capacitance was calculated for assessing the wettability and electrochemical properties of pristine and treated electrodes. The 600 °C GF has the highest specific capacitance of 34.8 Fg-1 at 100 mV s-1, but the 500 °C GF showed the best battery performance. The good battery performance of the 500 °C GF is attributed to the presence of oxygen functionalities and the absence of thermal degradation during heat treatment. The battery consisting of 500 °C GF electrodes offered the highest voltage efficiency of ~74%, Coulombic efficiency of ~94%, and energy efficiency of ~70% at 20 mA cm-2. Energy efficiency increased by 7% in a battery consisting of heat-treated GF in comparison to pristine GF. The battery is capable of operating for 100 charge-discharge cycles with an average energy efficiency of ~ 67% for over 100 cycles.

Effects of surfactant types on anthracite dust wettability: Experimental and molecular simulations

To study the wetting mechanism of surfactants at the solid–liquid interface of anthracite, a combination of experiments and molecular simulation was used to explore the adsorption and wetting processes of four surfactants, namely, fatty alcohol polyoxyethylene ether N = 9 (AEO9), Triton X-100, rapid penetrant T (PRT), and sodium alkyl ether sulfate (AES) on anthracite. The wetting mechanism of surfactants on anthracite was analyzed at both macroscopic and microscopic levels by surface tension, contact angle, settling time, and changes in surface morphology and functional groups on the anthracite surface. The presence of OH-π and C = O was determined to significantly enhance anthracite wettability. The anthracite/surfactant/water system was constructed from a microscopic perspective, and the interaction energies, relative concentration distributions along the Z-axis, diffusion coefficient (D) of water molecules, radial distribution functions (RDF) of hydrophilic groups and water molecules, and coordination numbers of the components were analyzed. The results show that the wetting effect depends on the adsorption state of the surfactant at the anthracite/water interface and the strength of the interaction between the surfactant and water molecules. The addition of surfactants enhances the adsorption thickness of water molecules along the Z-axis and generates more hydrogen bonds, which play a role in fixing water molecules and lead to a decrease in the D of water molecules. RPT forms the highest number of hydrogen bonds with water molecules and has the lowest D of 0.479 × 10-5 cm2/s, indicating strong wetting ability. The RDF of O atoms in surfactants and water molecules shows a similar trend, with two peaks one strong and one weak. The coordination numbers are 1.356, 1.057, 1.003, and 0.903, respectively. The final wettability of the surfactant on the anthracite depends on the synergistic interaction between the oxygen functional groups (OGs) as compared to the coordination number of the individual OGs.

Effect of MoS2 nanoparticles on the properties of Ni-W-SiC composite coatings

To improve the comprehensive protection performances of Ni-W-SiC composite coatings, we successfully manufactured Ni-W-SiC-MoS2 composite coatings using an electrodeposition technique on a 7075 aluminum alloy surface. We analysed the changes in microhardness, wear resistance, corrosion resistance, surface morphology and roughness of the composite coatings upon the addition of MoS2 nanoparticles. A microscopic characterisation of the Ni-W-SiC-MoS2 coatings was carried out by scanning electron microscope and atomic force microscope. The elemental composition was analysed by energy dispersive spectroscopy. The grain size was calculated by X-ray diffraction. The microhardnesses of the Ni-W-SiC-MoS2 composite coatings were evaluated by a microhardness tester, the wear resistance was tested by a rotary friction tester, and the corrosion resistance was evaluated using an electrochemical workstation. The tests indicate that the addition of MoS2 nanoparticles has significant effects on the micromorphology and grain size of Ni-W-SiC,and that they can uniformly codeposit with SiC nanoparticles in the Ni-W coating, exerting a synergistic effect on the improvement in the performance of the composite coating. When the amount of added MoS2 is 8g/L, the Ni-W-SiC-MoS2 coating has the smallest grain size and highest microhardness (917.6 HV). Its corrosion resistance is considerably improved compared to that of the Ni-W-SiC coating. When the MoS2 concentration is 6g/L, the Ni-W-SiC-MoS2 coating has the highest content of MoS2 nanoparticles, the friction coefficient reaches the minimum (0.24), and the wear resistance is best.

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.

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.

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.