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Bone tissue exhibits self-healing properties; however, not all defects can be repaired without surgical intervention. Bone tissue engineering offers artificial scaffolds, which can act as a temporary matrix for bone regeneration. The aim of this study was to manufacture scaffolds made of poly(lactic acid), poly(ε-caprolactone), poly(propylene fumarate), and poly(ethylene glycol) modified with bioglass, beta tricalcium phosphate (TCP), and/or wollastonite (W) particles. The scaffolds were fabricated using a gel-casting method and observed with optical and scanning electron microscopes. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetry (TG), wettability, and degradation tests were conducted. The highest content of TCP without W in the composition caused the highest hydrophilicity (water contact angle of 61.9 ± 6.3°), the fastest degradation rate (7% mass loss within 28 days), moderate ability to precipitate CaP after incubation in PBS, and no cytotoxicity for L929 cells. The highest content of W without TCP caused the highest hydrophobicity (water contact angle of 83.4 ± 1.7°), the lowest thermal stability, slower degradation (3% mass loss within 28 days), and did not evoke CaP precipitation. Moreover, some signs of cytotoxicity on day 1 were observed. The samples with both TCP and W showed moderate properties and the best cytocompatibility on day 4. Interestingly, they were covered with typical cauliflower-like hydroxyapatite deposits after incubation in phosphate-buffered saline (PBS), which might be a sign of their excellent bioactivity. [ABSTRACT FROM AUTHOR]

Transient liquid phase (TLP) bonding of Ti-6Al-4 V/UN32750 joint with a composite interlayer of Cu-0.5 wt.% CNT and a pure Cu interlayer has been investigated. TLP process was performed in a vacuum furnace at three different temperatures (900, 950, and 1000 °C) with a constant holding time (60 min). Microstructure and mechanical properties of all joints were studied using scanning electron and optical microscopes, microhardness, and shear tests. The x-ray diffraction (XRD) test was done on all fracture surfaces to do phase analysis at the interface. Results showed that the increase in the thickness of the TLP layer is associated with CNT addition, inferring that CNT enhances the diffusion of alloying elements across the interface. All joints experienced a reduction in the strength after CNT addition, with the highest strength obtained at 950 °C. The microhardness of the CNT-containing joints is higher than that of CNT-free samples due to the formation of plate-shaped Al-based phases and solid solution strengthening. All joints showed brittle fracture features. CNTs improved the brittle fracture to some extent, especially at 1000 °C. [ABSTRACT FROM AUTHOR]

Visual examination of the surface topography, in conjunction with the other sensors, may confirm the existence of chatter. Online chatter detection during real machining operations is possible with the use of sensors, and the presence of noise in their output and restricted bandwidth are the major drawbacks of these sensors. Productivity drops and manufacturing costs go up when there is a lot of chatter in the machining process. In the present paper, an integrated spindle tool system is modeled using finite element method with Timoshenko beam theory including rotational and shear deformation effects. To maximize the average stable depth of cut in an end milling process while simultaneously minimizing the chatter vibration levels, real time and offline strategies have been investigated. Machining experiments performed on Al6061-alloy specimens provide an empirical confirmation of the stability boundaries. The surface topography methods such as scanning electron microscope (SEM) and optical microscope images along with vibration levels are considered, to identify chatter marks under various machining conditions, which helps to assure cutting process stability. Stability lobe diagrams are plotted with these derived conditions and observed at an incremental level in the axial depths of the cut. The methodology shown in this paper improves the machining stability of the end milling with the reduction in the tool tip vibrations. [ABSTRACT FROM AUTHOR]

In this paper, the self-assembling nature of nano-doped liquid crystals is characterized using different techniques. Liquid crystals, namely 4, n-alkoxybenzoic acid (nOBA, where n = 7,8), doped with magnetic nanoparticles (Fe3O4 of size 20nm) are considered for the present study. The structural and morphological properties of nano-doped liquid crystals are determined by the techniques of X-ray diffraction and Scanning Electron Microscopy. Morphological properties like grains, grain boundaries, and crystal defects are elucidated using the scanning electron microscope technique. Structural properties such as crystal structure, grain size, inter-atomic spacing, lattice constant, and dislocation density are determined using X-ray diffraction studies. The characteristics measured from the X-ray diffraction studies are correlated using the statistical analysis of Scanning electron microscope images. This is an objective analysis of X-ray diffraction studies. In addition to these techniques, colorimetric studies of optical anisotropic liquid crystals are carried out by measuring the chromaticity coordinates and color purity. This study utilizes the polarizing optical microscope technique. Furthermore, the influence of nano dopants on the characteristics of liquid crystals with carbon chain length is also discussed. [ABSTRACT FROM AUTHOR]

In the present investigation, an effort has been made to join commercial pure titanium and stainless steel 304L by plasma-assisted heating techniques. The diffusion bonding is conducted at 750 °C with varying heating rates viz. 100, 150, 200, 250 °C/min with holding for 5 minutes with varying pressure condition (44 MPa). The bonding strength of the interfacial region is evaluated by the tensile test. The result shows that the diffusion of Fe in Ti leads to the formation and stabilization of Fe2Ti in the interfacial zone. To understand the effect of varying holding time and heating rate, the bond width is studied using optical and scanning electron microscopes. It is observed that the thickness of the joint is reduced by increasing the heating rate. This leads to maximum bonding strength 418 MPa for the bond made at 150 °C/min withholding the pressure to room temperature whereas the bonding strength falls to 340 MPa at 200 °C/min due to the formation of a thick brittle intermetallic compound. [ABSTRACT FROM AUTHOR]

Common tapeworms in poultry digestive tracts are called Raillietina species. The present study's objective is to characterize the morphological and genetic relationships between the cestode parasites that infect domestic pigeons (Columba livia domestica) in Saudi Arabia's Al-Qassim Region. Using optical and scanning electron microscopes, the general morphology and surface characteristics of the collected cestode parasites were examined. Using sequences from the ND1 and 18S rDNA gene areas, molecular analysis was used to confirm the taxonomy of this parasite based on its morphological characteristics. This demonstrated a high degree of similarity--up to 98.0% and 74.7%, respectively between the 18S rDNA and ND1 gene regions and other cestode species found in GenBank. Using close ties, phylogenetic research validated the placement of this Raillietina species within Davaineidae. [ABSTRACT FROM AUTHOR]

Magnesium AZ91/AlN-based surface composites have been synthesized using the friction stir processing (FSP) technique. The influence of particle addition during FSP on microstructural and mechanical properties has been investigated. Composite plates of 5, 10, and 15 vol. % AlN were synthesized using two-pass FSP with an axial force of 10 KN, a tool travel speed of 40 mm/min, and a tool rotation speed of 1200 rpm. The AZ91/AlN surface composites were analyzed microscopically with the use of an optical microscope, an x-ray diffractometer, and a scanning electron microscope. The prepared composites were tested for hardness and tensile strength. Micrographs taken in the stir zone revealed a consistent distribution of AlN particles throughout the AZ91 matrix. The AZ91/AlN surface composites were tested for hardness and tensile strength, and the findings showed that the AlN particles improved the mechanical properties without significantly decreasing ductility. The fracture surfaces of the composites were studied, and the mechanisms of fracture were identified. [ABSTRACT FROM AUTHOR]

The effect of current on resistance spot welding joints on metallurgic and mechanical properties is investigated experimentally using galvanized unequal-thickness DP600 steel sheets. The specimens were chosen to be 1.5 and 1.8 mm thicknesses. The parameters of the welding process were preferred as an electrode force at 5 kN, welding currents at 7, 9, 11, 13 and 15 kA and welding times at 180, 240, 300, 360 and 420 ms. The welded joint specimens were subject to tensile-shear strength testing to determine the ultimate tensile strength. Optimal specimens were inspected using optical microscopes and scanning electron microscopy. The effect of spot welding variables on the ultimate tensile strength was determined and the lobe diagram, which shows optimal current-time values, was obtained. The optimal welding parameters were carried out on new sheet metals successfully. The experimental results show that the welding current plays an important role in the especially crash energy absorption and load-carrying capability. [ABSTRACT FROM AUTHOR]

Machining of silica glass is a challenging task due to its physical properties like brittleness, electrically insulated, etc. Although with the use of electrochemical discharge, it is possible to make holes and channels in silica glass, but the generation of spark discharge and removal of materials is a complex phenomenon in the electrochemical discharge process. Several research works were carried out previously to control the spark discharge as well as machining accuracy using rotational tool, the addition of ultrasonic vibration, including a magnetic field, and the use of different electrolytes, etc. A novel tool feeding technique i.e. using a horizontal tool and vertically upward tool feeding technique was used during milling on glass. The effects of voltage, the tool feed rate (TFR) and the concentration of electrolyte on the material removal rate and machining quality were studied in this work. The machined channel was examined under an optical measuring microscope as well as scanning electron microscope. The machining surface was also observed using a coherence correlation interferometry image to analyze in-depth surface topography of machined channels. Material removal rate and Ra value of the bottom layer were measured. The material removal rate of 6.097 µg/min was noticed at 25 wt% of electrolyte concentration, 40 µm/s of TFR and 45 V of applied voltage. The bottom layer's surface roughness (Ra) was found as low as 0.222 µm (Ra) at parametric conditions of 40 V, 40 µm/s TFR, and 15 wt% electrolyte concentration by employing the developed novel tool feeding technique. [ABSTRACT FROM AUTHOR]

In the electric vehicles studied, the driven wheels and the differential, which are responsible for the transfer of power and rotational motion, are connected by half-shafts. The failure of two half-shafts in the rear gearbox of a three-wheeled electric vehicle, popularly known as a Tuk Tuk, is examined and evaluated in this research. Therefore, the primary goal of this work is to look at the factors that contribute to the failure of the aforementioned components. Visual examination and fractographic analysis were performed utilizing optical and scanning electron microscopes to investigate the half-shafts' mode of failure. Samples from both half-shafts were obtained for tensile testing, metallographic examination, chemical composition analysis, and fracture surface analysis. According to visual examination, reversed bending fatigue, occurring simultaneously with torsion loading, caused the fracture in the half-shaft to the left of the differential (rear view). Analysis of the fracture surface of the half-shaft to the right of the differential revealed that it resulted mainly from bending fatigue loading. Moreover, regarding the mechanical design safety of the half-shafts, calculations were performed considering different trajectories, limit speeds, and different design criteria. Finally, some recommendations are drawn to improve the design safety of this mechanical component. [ABSTRACT FROM AUTHOR]

Incoloy 800 is a Fe-based super alloy used primarily in high-temperature applications like boilerplates due to its ability to maintain its austenitic phase. Samples of 100 × 20 × 5 mm were manufactured in vertical orientation using selective laser melting (SLM) and were annealed at 980 °C for 15 min. Annealed samples were cold rolled at room temperature, in multiple passes to 20, 40, 60 and 80% reduction in thickness, perpendicular to the building direction. The aim of this study is to understand the strain hardening effect upon rolling and also to know the effect of cold rolling on texture, microstructure and hardness after rolling the annealed alloy. Microstructural features were observed under optical microscope and scanning electron microscope while the texture measurement was done using X-ray goniometer. Typical fish scale morphology was observed in the transverse plane of as-built condition, which was diminished in annealed samples. SEM study shows fine grains along with traces of lamellar cell morphology. Hardness increased with an increase in percentage reduction. Austenite (γ) phase was detected as the only phase in XRD analysis. The bulk texture of annealed sample revealed strong copper texture until 40% rolling, and thereafter, it reduced. Goss texture component showed a similar trend, while brass texture increased up to 60% rolling condition and thereafter diminished. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of the Ni element on the properties of AlCoCrFeMn HEAs, this experiment prepared AlCoCrFeMn and AlCoCrFeNiMn HEAs by using a laser-ignition self-propagation sintering technique with an equal molar ratio. And analyzed the effect of the Ni element on the microstructure of AlCoCrFeMn HEAs by using a metallurgical optical microscope (OM), scanning electron microscope (SEM), energy spectroscopic analysis (EDS), X-ray diffraction (XRD), and other experiments. Characterization equipment was used to analyze the effect of the Ni element on the microstructure, physical phase structure, wear resistance, compressive properties, and corrosion resistance of AlCoCrFeMn HEA materials. The results show that after the addition of the Ni element, the AlCoCrFeNiMn HEA changes from a single BCC phase to one consisting of BCC and a small amount of an FCC phase, with an equiaxial organization, and the yield strength reaches 780 MPa and the compressive strength is 3920 MPa. The corrosion rate is 2.08 × 10−3 mm/a, and the corrosion resistance and mechanical properties are greatly increased. [ABSTRACT FROM AUTHOR]

Present study employes a picosecond laser (532 nm) for selective P1 laser scribing on the indium tin oxide (ITO) layer and subsequent fine‐tuning of P1 scribing conditions with machine learning (ML) techniques. Initially, the scribing is performed by varying different laser parameters and further evaluate them via an optical microscope and two probe resistivity measurements. The corresponding scribing width and sheet resistance data are used as input databases for ML analysis. The classification and regression tree (CART)‐based ML analysis revealed that median pulse energy <5.7 μJ insufficient to separate the adjacent scribing regions. While pulse energy >5.7 μJ, APL > 35%, LSO > 46%, and processing speed ≥1250 mm s−1 gives ≥16 μm of scribing width. Further, the decision tree (DT) analysis showed that pulse energy of ≥8.1 μJ, and LSO ≥ 37% are required for electrically isolated lines. The feature importance score suggests that laser fluence and pulse energy determined the scribing width, whereas electrical isolation strongly depends on LSO and processing speed. Finally, the ML achieved conditions experimentally validated and reassessed via scanning electron microscope, and atomic force microscopy aligns well with optical microscope measurements. [ABSTRACT FROM AUTHOR]

In this paper, the solid-state shear milling (S3M) strategy featuring a very strong three-dimensional shear stress field was adopted to prepare the high-performance polyoxymethylene (POM)/molybdenum disulfide (MoS2) functional nanocomposite. The transmission electron microscope and Raman measurement results confirmed that the bulk MoS2 particle was successfully exfoliated into few-layer MoS2 nanoplatelets by the above simple S3M physical method. The polarized optical microscope (PLM) observation indicated the pan-milled nanoscale MoS2 particles presented a better dispersion performance in the POM matrix. The results of the tribological test indicated that the incorporation of MoS2 could substantially improve the wear resistance performance of POM. Moreover, the pan-milled exfoliated MoS2 nanosheets could further substantially decrease the friction coefficient of POM. Scanning electron microscope observations on the worn scar revealed the tribological mechanism of the POM/MoS2 nanocomposite prepared by solid-state shear milling. The tensile test results showed that the pan-milled POM/MoS2 nanocomposite has much higher elongation at break than the conventionally melt-compounded material. The solid-state shear milling strategy shows a promising prospect in the preparation of functional nanocomposite with excellent comprehensive performance at a large scale. [ABSTRACT FROM AUTHOR]

The use of aluminum alloys in automobiles is expanding, and the potential for additional increases is significant. Further growth will be determined by improvements in material qualities for existing applications or the discovery of new applications. Alloy A-356 (LM25) is commonly employed for high-quality alloy wheel rims in various motor vehicles, constituting 40% of global car usage. This study introduces 0.2% Cu into the Al–Si–Mg alloy system to enhance the mechanical properties. The alloy blend is cast into a metal mold, subjected to a 4-h cure at 540 °C, quenched with water, and precipitation hardened for 12 h at 1800 °C. Optical and scanning electron microscopes are utilized to analyze the alkali microstructure. The mechanical properties of alloyed and unalloyed castings, including hardness and tensile test results, are examined in untreated and heat-treated states. Fracture surfaces of tensile specimens are scrutinized. Intermetallic compounds formed during solidification are studied using scanning electron microscopy and x-ray diffraction analysis. The tensile strength under unalloyed (LM25) and alloyed (LM25 + 0.2 wt. % Cu) conditions before and after heat treatment [(72, 165.4 and 88.3, 237.1) and (78, 179.6 and 98, 252.9, respectively)] shows a significant increase. [ABSTRACT FROM AUTHOR]

The current research aims to fabricate the new PMMA/PEO/SiC/BaTiO3 nanostructures (PMMA—poly(methyl 2-methylpropenoate), PEO—polyethylene oxide) to use them in biomedical purposes as the radiation-shielding and in antibacterial applications due to their distinguished chemical and physical properties as well as a good gamma-ray attenuation coefficients and high antibacterial effectiveness. The PMMA/PEO/SiC/BaTiO3 nanostructures are prepared with different weight percentages of silicon carbide (SiC)/barium titanate (BaTiO3) nanoparticles (NPs) and PMMA/PEO blend to obtain nanostructures with low-weight, good flexibility, and good processability. The morphology of films’ surface for PMMA/PEO/SiC/BaTiO3 nanostructures is searched by optical microscope (OM) and scanning electron microscope (SEM). The SiC/BaTiO3 NPs are highly homogenous within the PMMA/PEO medium, according to the OM and SEM investigations. The attenuation coefficients are tested using 137Cs sources. The results demonstrate that the attenuation coefficient of PMMA/PEO is enhanced by rising of SiC/BaTiO3 NPs. The antibacterial results show that the PMMA/PEO/SiC/BaTiO3 nanostructures have antibacterial effectiveness for gram-positive and gram-negative organisms. Therefore, the PMMA/PEO/SiC/BaTiO3 nanostructures can be employed as a radiationshielding material as well as an antibacterial agent for use in the medical and environmental applications. [ABSTRACT FROM AUTHOR]

Small-sized stainless steel hand files are conventionally employed in root canal treatment procedures for canal scouting and for glide path establishment, owing to their superior flexibility and proficiency in navigating confined spaces. Given the diversity of brands available in the market, there exists potential variability in their physical characteristics, thereby influencing clinical performance. Consequently, this study aims to conduct a comparative analysis of the design, metallurgy, and mechanical characteristics among seven stainless steel hand file brands across ISO sizes 06, 08, and 10. A total of 315 new 25 mm length stainless steel hand files with apical sizes of 0.06, 0.08, and 0.10 from seven distinct brands were included in the study. A meticulous inspection of all instruments was undertaken to identify any structural deformations that might render them ineligible for the study. The design inspection involved the random selection of instruments from each group, which were examined under various microscopes, including a dental operating microscope, optical microscope, and scanning electron microscope. Furthermore, two instruments from each group underwent energy-dispersive X-ray spectroscopy analysis for elemental composition documentation. Mechanical tests were conducted to evaluate the instruments' resistance to lateral deformation (buckling) and their microhardness. Statistical analysis was executed using the nonparametric Mood's median test, with a predetermined significance level of 0.05. Regarding the instruments design, all files exhibited an active blade length ranging from 16 to 17 mm. However, variations were observed in the number of spirals, tip designs, and sizes, with the API K-File notably larger in sizes 0.06 and 0.08 compared to the other instruments. Despite uniform elements composition, differences in geometric features and mechanical properties were evident. Concerning buckling strength, the API K-File demonstrated superior performance across all tested sizes, while the Dentsply ReadySteel, SybronEndo, and Mani K-Files exhibited lower results (p < 0.05). In microhardness assessments, both the API and Oro K-Files displayed the lowest outcomes, with medians of 531 HVN and 532 HVN, respectively, whereas the SybronEndo K-File exhibited the highest microhardness (657 HVN). Despite similar metallurgical composition, the observed distinctions in geometric features and mechanical properties underscore the impact of the manufacturing process on the characteristics of glide path stainless steel endodontic files. These disparities may ultimately influence their clinical performance. [ABSTRACT FROM AUTHOR]

The activity of biomaterials used during endodontic treatment can be affected by various factors. One of them is the chemical action of the irrigant that they are exposed to. The aim of this multimethod ex vivo study was to evaluate the influence of ethylenediaminetetraacetic acid (EDTA) on the surface appearance and chemical composition of Biodentine used in perforation repair. Twenty material specimens were prepared according to manufacturers' recommendations and divided into two setting-time-based groups, tested after 45 min (group A) and 24 h (group B) of setting. Material was irrigated with 17% EDTA solution with or without simultaneous ultrasonic activation. The surface characteristics and the chemical composition analysis of the Biodentine specimens were performed with the aid of a scanning electron microscope (SEM) and an energy dispersive spectroscopy (EDS) method, respectively. The volumetric loss of material was measured by dedicated digital software in an optical microscope. Statistical analysis was performed. The EDS study confirmed that after the rinsing protocol, the percentage content of elements differed between the groups. The EDTA rinse, whether ultrasonically activated or not, visibly affected the surface appearance and chemical composition of Biodentine. The specimens' surface subjected to irrigation was more irregular under SEM than in a control group. The US activation of the liquid amplified its impact on the tested material. The average volume loss in group A after 5 min irrigation was 3.98 µm3 for each µm2 of the chosen area and it increased up to 7.74 µm3/μm2 after the ultrasonic activation. In group B, indicated volume loss values were 6.30 and 11.70 µm3/μm2 for 5 min irrigation without and with US activation, respectively. Using a 20 min irrigation time and ultrasonic activation increased it up to 32.71 µm3/µm2. Each rinsing protocol involving irrigation with ethylenediaminetetraacetic acid modified the surface features and the chemical composition of the evaluated hydraulic tricalcium silicate cement. Further research is needed to indicate the possible impact of the observed changes on its long-term clinical performance. [ABSTRACT FROM AUTHOR]

We describe a new class of the periodic banding of Ag2O precipitates through reaction-transport-reaction processes in an agarose-hydrogel column; the gel contains NaNO3 as an additive and is inserted between Ag and Ti rods with an applied constant voltage of 4.0-7.0 V. Submillimeter-scale periodic dark-brown precipitation bands were transiently generated with high reproducibility in this system, in which (i) electrochemical reactions at the metal rods to generate Ag+ and OH-, (ii) transportation of the reactant ions by the electric field, and (iii) reactions to produce Ag2O are expected to couple. The bands successively emerged mainly toward the cathode, accompanied by substantial changes in the electric current through the gel. The periodic banding depended on the applied voltage, duration of application, and concentration of NaNO3 initially loaded in the gel. The banding was most clearly observed in a 2.0 mass% agarose gel column containing 0.005 MNaNO3 under a constant applied voltage of ~5.5 V for ~3 h. This optimal condition resulted in more than ten periodic bands, of which the bandwidth (w) and the distance between the adjacent bands (d) were randomly distributed around the average values: for the bands formed up to 2 h, w = 0.25 ± 0.04mmand d = 0.42 ± 0.05 mm; for the bands formed after 2 h, w = 0.42 ± 0.11mmand d = 0.68 ± 0.07 mm. The generated periodic bands were gradually painted out with time to form an almost continuous broad band, even after the applied voltage was discontinued, although immersion of the gel in deionized water for 3 h could suppress this uniformization. Observations using optical and scanning electron microscopes with an energy-dispersive X-ray detector suggested that the periodic bands were composed of gelatinous Ag2O and micrometer-scale (1-50 μm) clusters, which comprised Ag-abundant nanoparticles with considerable size dispersion (10-500 nm). The relationship between the periodic banding and inhomogeneous distribution of the reactant ions and potential applications of the observed banding phenomena are discussed. [ABSTRACT FROM AUTHOR]

The present in vitro study focuses on the filling ability of three different bioceramic cements with or without the addition of a bioceramic sealer in an open apex model on the marginal apical adaptation, tubule infiltrations, and void distributions as well as the interface between the cement and the sealer materials. To this end, sixty mandibular premolars were used. MTA-Biorep (BR), Biodentine (BD), and Well-Root Putty (WR) were used to obturate the open apex model with or without the addition of a bioceramic sealer, namely TotalFill® BC sealer™ (TF). A digital optical microscope and scanning electron microscope (SEM) were used to investigate the cement–dentin interface, marginal apical adaptation, and the material infiltration into the dentinal tubules. Micro-computed X-ray tomography and digital optical microscopy were used to investigate the cement–sealer interface. The results were analyzed by using the Kruskal–Wallis test. No significant difference was found between the groups for the marginal apical adaptation quality (p > 0.05). Good adaptation of the dentin–cement interface was found for all tested groups and the sealer was placed between the cement material and dentinal walls. All the groups demonstrated some infiltrations into the dentinal tubules at the coronal part except for the BR group. A good internal interface was found between the cement and the sealer with the presence of voids at the external interface. A larger number of voids were found in the case of the BD-TF group compared to each of the other two groups (p < 0.05). Within the limitations of the present in vitro study, all the groups demonstrated good marginal apical adaptation. The use of a sealer in an open apex does not guarantee good filling and, in addition, creates voids at the external interfaces with the dental walls when the premixed sealer is used with powder–liquid cement systems. The use of a premixed bioceramic cement could offer fewer complications than when a powder–liquid cement system is used. [ABSTRACT FROM AUTHOR]

Bone tissue is one of the most transplanted tissues. The ageing population and bone diseases are the main causes of the growing need for novel treatments offered by bone tissue engineering. Three-dimensional (3D) scaffolds, as artificial structures that fulfil certain characteristics, can be used as a temporary matrix for bone regeneration. In this study, we aimed to fabricate 3D porous polymer scaffolds functionalized with tricalcium phosphate (TCP) particles for applications in bone tissue regeneration. Different combinations of poly(lactic acid) (PLA), poly(ethylene glycol) (PEG with molecular weight of 600 or 2000 Da) and poly(ε-caprolactone) (PCL) with TCP were blended by a gel-casting method combined with rapid heating. Porous composite scaffolds with pore sizes from 100 to 1500 µm were obtained. ATR-FTIR, DSC, and wettability tests were performed to study scaffold composition, thermal properties, and hydrophilicity, respectively. The samples were observed with the use of optical and scanning electron microscopes. The addition of PCL to PLA increased the hydrophobicity of the composite scaffolds and reduced their susceptibility to degradation, whereas the addition of PEG increased the hydrophilicity and degradation rates but concomitantly resulted in enhanced creation of rounded mineral deposits. The scaffolds were not cytotoxic according to an indirect test in L929 fibroblasts, and they supported adhesion and growth of MG-63 cells when cultured in direct contact. [ABSTRACT FROM AUTHOR]

The effect of aging treatments at various temperatures on the mechanical properties and microstructure of 10B21 cold heading steel with a 20% reduction in area (ε = 0.1) was investigated. The mechanical properties were evaluated based on tensile tests and hardness tests, while the evolution of microstructure was observed by using an optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The results reveal that aging treatment enhance the strength and hardness of 10B21 cold heading steel after drawing, and the highest values of strength and hardness are attained at an aging temperature of 300 °C. Specifically, the yield and ultrahigh tensile strength after aging at 300 °C are measured at 620 MPa and 685 MPa, respectively, which are 30 MPa and 50 MPa higher than the cold-drawn sample. Moreover, the hardness after aging at 300 °C reaches 293 HV, which has an increase of 30 HV compared to the cold-drawn state. The improvement in mechanical properties may be related to the strain-aging mechanism and the increased density of dislocations. In addition, the analysis of the TEM results reveal that the presence of the second-phase Ti(C,N) contributes to pinning the dislocations, whereas the dislocations are pinned between the cementite (Fe3C) lamellar and stacked at the grain boundaries, leading to strain hardening of the material. [ABSTRACT FROM AUTHOR]

Fiber-reinforced emulsified asphalt (FEA) is widely used in asphalt pavement structures as a stress-absorption layer. This study aimed at developing a multifunctional fiber-reinforced emulsified asphalt (MFEA) by empowering the FEA with the self-sensing ability. To achieve this purpose, carbon nanotubes (CNTs) were grafted onto the basalt fibers in the FEA. An optical microscope and scanning electron microscope (SEM) were respectively used to investigate the distribution of CNTs onto the fibers and the microstructure of CNT/fiber composite (CFC). The fabrication process of CFC was optimized based on the distribution homogeneity of the CNTs. The self-sensing ability of the MFEA was then evaluated in the laboratory using an electrochemical workstation. Based on the experimental and analytical results, 1.5 mg/mL was recommended as the optimal dosage of the suspension of CNTs for grafting CNTs onto the fiber. The electrical resistance of the developed MFEA was found to be isotropic and sensitive to the demulsification state, EA/CFC mass ratio, temperature, loading speed, and deformation magnitude, which confirms the potential of using developed MFEA as a self-sensing layer to monitor its response to environmental and traffic variation. Besides, the direct tension and pull-out tests indicate the positive influence of grafting CNTs onto basalt fibers on the mechanical performance of FEA. [ABSTRACT FROM AUTHOR]

Fly ash (FA) and coconut shell ash (CSA) are solid byproducts of industrial and agricultural waste, respectively, that are produced in enormous amounts around the world. It is considered to be a contaminant in the environment. Because of the negative impacts on the environment, research on the use of FA and CSA is being undertaken all over the world. The current study focuses on the use of FA and CSA as reinforcement in an AA7075 alloy matrix through two-step stir casting. The present study also reported on the characteristics of newly developed novel composites and their environmental effects using leaching tests. The inclusion of ceramic particles can enhance the microstructure, mechanical, and corrosion characteristics of AA7075 alloys. Optical and scanning electron microscopes were used to evaluate the homogenous distribution of FA and CSA particles in the matrix. Contrasting with the homogeneous alloy, the hybrid composite, composed of 5 wt% FA and 5 wt% CSA, exhibited a remarkable surge of 27% in maximum hardness and a 19% increase in tensile strength. To explore the corrosion resistance of these newly created composites, polarization tests and AC impedance spectra were employed. Immersing the meticulously crafted specimens in a 3.5% sodium chloride solution, the corrosion assessment revealed that the composite with 5 wt% FA and 5 wt% CSA outperformed the traditional monolithic AA7075 alloy in terms of corrosion resistance. [ABSTRACT FROM AUTHOR]

The mechanical properties of a defect-free laser melting (PBF-LB) deposit of an AISI 316L steel alloy were assessed by means of an instrumented indentation test (IIT), at both the macro- and nano-scales. The inherent non-equilibrium microstructure of the alloy was chemically homogenous and consisted of equiaxed grains and large-elongated grains (under the optical microscope) with irregular outlines composed of a much finer internal cell structure (under the scanning electron microscope). Berkovich and Vickers indenters were used to assess the indentation properties across individual grains (nano) and over multiple grains (macro), respectively. The nano-indentation over the X-Y plane revealed nearly constant indentation modulus across an individual grain but variable on average within different grains whose value depended on the relative orientation of the individual grain. The macro-indentation test was conducted to analyze the tensile-like properties of the polycrystalline SS 316L alloy over the X-Y and Y-Z planes. The macro-indentation test provided a reliable estimate of the ultimate tensile strength (UTS-like) of the alloy. Other indentation properties gave inconsistent results, and a post factum analysis was, therefore, conducted, by means of a new approach, to account for the presence of residual stresses. The already existing indentation data were supplemented with new repeated indentation tests to conduct a detailed analysis of the relaxation ability of compressive and tensile residual stresses. The developed methodology allows the effect of residual stresses and the reliability of measured macro-indentation properties to be examined as a function of a small group of indentation parameters. [ABSTRACT FROM AUTHOR]

In this study, the effect of increasing exposure time on the microstructures, porosity, mechanical properties and corrosion behavior of selective laser melted sample Al-Si10-Mg powder was investigated. The samples were processed at the same power (375 W) and scan speed (2000 mm/s), but with increasing exposure time. Exposure time equal to 40, 50 and 60 µs was applied. The features of the analyzed samples show that with increasing exposure time, greater efficiency of the heat input was obtained, with a larger size of the melt pool and Si particles and lower porosity. Specifically, at the highest exposure time the melt pool showed an increase of 19% in width and 48% in depth, while the volume percentage of the voids decreased by 50% with respect to the lowest exposure time. Moreover, with the coarser microstructure being associated with a lower level of voids, the average hardness is similar for the analyzed samples. Corrosion resistance was evaluated, being one of the most important properties that may affect the service performance of Al-Si10-Mg alloy in the aerospace, marine and automotive industries. The potentiodynamic curves of the samples show that the voids occurrence is more significant with respect to the scale of the microstructure on corrosion behavior, with the sample processed at the highest exposure time being the more resistant to corrosion. The experimental techniques used in the present study were Optical Microscope (OM), Scanning Electron Microscope (SEM), hardness and X-Ray Computed Tomography. [ABSTRACT FROM AUTHOR]

Increasing interest in utilizing bio-lubricants has been sparked by pollution caused by the mineral oil-based lubricants and their depletion. This study aimed to assess the effectiveness of Jatropha oil based grease as a basis and sodium thickener as an additive. The grease's lubricating abilities were tested using the ASTM 2266 four ball test and molybdenum disulphide as an additive. According to the findings, adding molybdenum disulphide particles decreased wear and the coefficient of friction, with the latter falling by 69% when compared to virgin Jatropha grease. Given that Jatropha grease passed the four ball test, a simulation of real-world conditions, this indicates that it is a reliable lubricant. Wear examinations were performed on steel balls using an optical microscope and scanning electron microscopy, and the results were consistent. It was found that addition of 0.25% MoS2 to virgin Jatropha grease reduced coefficient of friction to 0.12 (69%) from 0.39. Similarly wear scar diameter reduced from 800.583 µ to 788.44 µ in presence of 0.25% MoS2 blended grease. The study concludes that the grease prepared could an alternative to grease made from mineral oils. The focus on adopting Jatropha grease as a more sustainable and bio-degradable option can preserve the environment. [ABSTRACT FROM AUTHOR]

Thermal additive centrifugal abrasive flow machining (TACAFM) is the latest hybrid of abrasive flow machining, which involves a combination of centrifugal action of rotating electrode and the spark to manage the limitation of low material removal (MR). The present investigation involves the study of the morphology of internal surface hollow cylindrical brass surface finished by TACAFM process. The researchers proposed a novel spline-shaped centrifugal force-generating electrode with a curved blade instead of straight blade for improving the process efficiency. The computation of MR and percentage improvement in surface finish (%ΔRa) is done using the proposed electrode with curved blade, and the results are compared with the primitive electrode with straight blade against the process parameters (supply current, duty cycle, abrasive concentration, rotational speed of centrifugal force generating electrode and the extrusion pressure). The surface roughness plot using Taylor-Hobson tallysurf, micrographs taken by optical microscope and SEM images were used for analysis of the finished workpiece surface. The proposed electrode resulted in an 8.5% increase in MR and 27.38%ΔRa compared to initial straight spline-shaped electrode used for TACAFM process. Also, XRD and EDAX analysis was done to predict the morphological change on the finished workpiece surface. [ABSTRACT FROM AUTHOR]

Aluminum alloy 7075 exhibits excellent mechanical properties and is used in many applications as structural parts under different temper conditions. These parts could be subjected to erosive media in their service life. For this reason, the erosion resistance and tempering conditions of 7075 alloy are of interest to many researchers. In this study, the erosion behavior of forged 7075 under different hardening conditions was investigated. Erosion particles of Al2O3 with 120 mesh (110-130 μm) were used for the tests. The images of SEM and optical microscope and profilometer were analyzed. The effects of morphology and wear mechanism were clarified. The test results show that T4 temper condition has a moderate hardness, but the lowest erosive resistance. Although T0 has moderate erosive resistance, it has the lowest hardness. T6 condition has the best results in both erosive resistance and hardness. Because of the formation of fine, coherent precipitates within the aluminum matrix, these precipitates can act as obstacles to dislocation movement, increasing the material's resistance to deformation and erosion. [ABSTRACT FROM AUTHOR]

Using torch brazing techniques, 316 stainless steel was brazed to CP copper using flux-coated low silver content filler with 20% Ag. The brazing torch utilized a fuel mixture of propane gas with oxygen to produce the required heating amount due to the possibility of economic interest in employing low-silver-content filler. The brazing filler's braze ability with SUS304 and copper was scrutinized and deeply analyzed. A ferrite barrier layer was made on the stainless-steel side, and an excellent brazed joint was produced. Metallurgical studies using an optical microscope and a scanning electron microscope (SEM) confirmed the production of a ferrite layer. This layer's advantages were carefully examined with metallurgical testing, electron diffraction scanning (EDS), EDS mapping, and EDS line analyses, including preventing copper intergranular penetration into the stainless-steel grain boundary. The mechanical properties of the brazed joint and its usability were assessed through Vickers microhardness and tensile tests on the brazing seam and both base metals. The results of the brazing process showed that using flux-coated low-silver brazing techniques produced strong joints with satisfactory mechanical properties. These techniques are a cost-effective alternative to high-priced brazing fillers with high silver content. Geometrical models simulated the heat distribution using ANSYS and SOLIDWORKS software to analyze penetration depth, joint quality, surface cracks, and the relation between molten filler density variation and the wetting process. [ABSTRACT FROM AUTHOR]

In the current study, the effect of the weight percentage of filler and additive powder on the microstructural and mechanical properties of the wide gap activated diffusion brazing process was studied. IN738LC base metal powder and AMDRY BRB filler were used as filler metal for IN738LC superalloy brazing. Subsequently, diffusional heat treatment and aging cycle were used to modify the microstructure and mechanical properties in the restoration structure. Optical microscope and scanning electron microscope were used to identify the phases in the braze area and four-point bending tests were performed to evaluate the mechanical properties of the wide gap. For the sample brazed at 1180 °C for 30 min, heat treated at 1120 °C for 4 h, and aged at 850 °C for 24 h, the porosity and eutectic phases in the brazed area and the diffusion-affected zone maintained as low as possible. Thus, it can be referred to as the optimized sample. The samples containing 40 wt% filler had the optimum mechanical properties at ambient temperature and high temperature. Fractography showed that the place of crack initiation was mainly in the filler metal. [ABSTRACT FROM AUTHOR]