Introduction. Tendons are specialised, heterogeneous connective tissues, which represent a significant healthcare challenge after injury. Primary surgical repair is the gold standard modality of care; however, it is highly dependent on the extent of injuries. Tissue engineering represents an alternative solution for good tissue integration and regeneration. In this review, we look at the advanced biomaterial composites employed to improve cellular growth while providing appropriate mechanical properties for tendon and ligament repair. Methodology. Comprehensive literature searches focused on advanced composite biomaterials for tendon and ligament tissue engineering. Studies were categorised depending on the application. Results. In the literature, a range of natural and/or synthetic materials have been combined to produce composite scaffolds tendon and ligament tissue engineering. In vitro and in vivo assessment demonstrate promising cellular integration with sufficient mechanical strength. The biological properties were improved with the addition of growth factors within the composite materials. Most in vivo studies were completed in small-scale animal models. Conclusions. Advanced composite materials represent a promising solution to the challenges associated with tendon and ligament tissue engineering. Nevertheless, these approaches still demonstrate limitations, including the necessity of larger-scale animal models to ease future clinical translation and comprehensive assessment of tissue response after implantation.
A Fe 2 O 3 nanoporous structure was prepared by using hydrothermal route; its physicochemical properties were effectively characterized using XRF, BET, FT-IR, VSM, SEM and EDX, DLS, XRD, and PL techniques. The surface area of the magnetic nanoporous structure Fe 2 O 3 was higher than the normally synthesized Fe 2 O 3 nanoparticle. The outcome of the photocatalytic removal of the chromium (VI) below the visible light irradiation confirmed that 82.11% of Cr(VI) was degraded by the Fe 2 O 3 nanomaterials at 120 min of irradiation time. The improved photocatalytic activity of the nanoparticle was ascribed to efficient electron-hole separation. Fe 2 O 3 was set up to be a tough and constant photocatalyst throughout recycling experiments. The conceivable mechanism for the electron-hole separation process on the heterojunction was probable. The synthesized samples own low band gap energy and a hollow structure appropriate for the improved photocatalytic activity. The toxicity of the samples was measured by using Mus musculus skin melanoma cells (B16-F10 (ATCC®, CRL-6475TM) which are set up to be safe for human cells; as a result, this systematic approach provides a better alternative upconversion material for integral photoabsorption.
“Graphitic carbon nitride” synthesized by the solvothermal reaction between cyanuric chloride (C 3 N 3 Cl 3 ) and sodium amide (NaNH 2 ), which was one of the most common methods reported so far, was carefully examined by several analytical techniques for its chemical and structural characteristics. The chemical quantification by the electron microprobe and combustion methods showed that the product synthesized has a significant amount of hydrogen with a composition C 3 N 5 H 3 . Moreover, we found by FT-IR and IR-Raman measurements that the product consists mainly of stacked s -triazine units on the basis of the structural framework of cyanuric chloride, suggesting that s -triazine-based carbon nitride is more stable than heptazine-based one under a mild temperature condition (~200°C). The present study clearly demonstrates that hydrogen-free, pure graphitic C 3 N 4 cannot be produced by the present solvothermal reaction proposed by the earlier study.
As for magnesium (Mg) alloys, it has been noted that they are inferior to plastic deformation, but improvement in the mechanical properties by further refinement of grain size has been recently suggested. It means the importance of atomistic view of polycrystalline interface of Mg crystal. In this study, to discuss the deformation mechanism of polycrystalline Mg, atomistic grain boundary (GB) models by using coincidence site lattice (CSL) theory are constructed and are simulated for their relaxed and deformatted structures. First, GB structures in which the axis of rotation is in [11¯00] direction are relaxed at 10 Kelvin, and the GB energies are evaluated. Then, the deformation mechanism of each GB model under uniaxial tensile loading is observed by using the molecular dynamics (MD) method. The present MD simulations are based on embedded atom method (EAM) potential for Mg crystal. As a result, we were able to observe atomistically a variety of GB structures and to recognize significant difference in deformation mechanism between low-angle GBs and high-angle GBs. A close scrutiny is made on phenomena of dislocation emission processes peculiar to each atomistic local structure in high-angle GBs.
This study aimed to improve the thermal conductivity of the Aluminium 6063 for heat sinks applications used in Central Processing Unit (CPU) of computers. Several studies had used different additional elements for this goal. In this paper, we studied the influence of Titanium and Boron addition on the thermal conductivity of Aluminium 6063. Several casting alloys samples were prepared with different percentage of addition elements and then heat-treated by homogenization and aging treatments. The results showed an important modification in thermal conductivity value per rapport to the reference metal, depending on the element of addition and its percentage. The bigger evolution was by using Boron in small percentage. More than 13% of the improvement was realized in the thermal conductivity with the addition of only 0.05% of Boron.
Dispersions of individual carbon nanotubes (CNTs) are crucial for nanodevices and polymer/CNTs nanocomposites. In this paper, stable and homogenous dispersions of individual multiwalled carbon nanotubes (MWCNTs) have been synthesized. The factors influencing the dispersibility mechanism, including the surfactant concentration and the pH value, have been investigated. SEM images display the impurities sticking on MWCNTs which have been removed. The oxygen-containing groups on the surface of MWCNTs sample have been detected through FT-IR and Raman spectra. All experimental results illustrate that using fullerenols as surfactant can greatly improve the dispersibility of MWCNTs. Moreover, the prepared dispersions exhibit good stability that the sediment percentage of fullerenols-MWCNTs is only 5.2% after 5 days.
Well-dispersed nanoscale zero-valent iron (NZVI) supported inside the pores of macroporous silica foams (MOSF) composites (Mx-NZVI) has been prepared as the Cr(VI) adsorbent by simply impregnating the MOSF matrix with ferric chloride, followed by the chemical reduction with NaHB 4 in aqueous solution at ambient atmosphere. Through the support of MOSF, the reactivity and stability of NZVI are greatly improved. Transmission electron microscopy (TEM) results show that NZVI particles are spatially well-dispersed with a typical core-shell structure and supported inside MOSF matrix. The N 2 adsorption-desorption isotherms demonstrate that the Mx-NZVI composites can maintain the macroporous structure of MOSF and exhibit a considerable high surface area (503 m 2 ·g −1 ). X-ray photoelectron spectroscopy (XPS) and powder X-ray diffraction (XRD) measurements confirm the core-shell structure of iron nanoparticles composed of a metallic Fe 0 core and an Fe(II)/Fe(III) species shell. Batch experiments reveal that the removal efficiency of Cr(VI) can reach 100% when the solution contains 15.0 mg·L −1 of Cr(VI) at room temperature. In addition, the solution pH and the composites dosage can affect the removal efficiency of Cr(VI). The Langmuir isotherm is applicable to describe the removal process. The kinetic studies demonstrate that the removal of Cr(VI) is consistent with pseudo-second-order kinetic model.
The atmospheric conditions and other facilities to rear silk filaments are good in Ethiopia. In Awassa, Awash Melkassa, and Kombolcha silk rearing is started with good progress. The quality of the cocoons produced in the country is not determined in relation to commercial silk produced in major silk producing countries. So far there was no information available about the basic properties of silk filaments produced. In this research paper, the different physical properties of the eri and mulberry cocoon and their filaments were evaluated. Eri cocoons have shell ratio of approximately 14%, average fiber fineness of 3 dtex, and average weight of 3.2–3.3 g, while mulberry cocoons have raw silk ratio of 13-14%, average fiber fineness of 2 dtex, and average weight of 1.5 g. Even though the method of rearing, handling, and harvesting of the cocoons is poor, the physical properties of the silk produced in Ethiopia fall within the limits of commercial silk produced in major silk producing countries.
Cobalt ferrite (CoFe 2 O 4 ) and silica (SiO 2 ) nanopowders have been prepared by the microwave hydrothermal (M-H) method using metal nitrates as precursors of CoFe 2 O 4 and tetraethyl orthosilicate as a precursor of SiO 2 . The synthesized powders were characterized by XRD and FESEM. The (100 − x ) (CoFe 2 O 4 ) + x SiO 2 (where x = 0%, 10%, 20%, and 30%) composites with different weight percentages have been prepared using ball mill method. The composite samples were sintered at 800°C/60 min using the microwave sintering method and then their structural and morphological studies were investigated using X-ray diffraction (XRD), Fourier transformation infrared (FTIR) spectra, and scanning electron microscopy (SEM), respectively. The effect of SiO 2 content on the magnetic and electrical properties of CoFe 2 O 4 /SiO 2 nanocomposites has been studied via the magnetic hysteresis loops, complex permeability, permittivity spectra, and DC resistivity measurements. The synthesized nanocomposites with adjustable grain sizes and controllable magnetic properties make the applicability of cobalt ferrite even more versatile.
H-Zeolite A is an efficient, excellent, and reusable catalyst for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives by one-pot synthesis of β-naphthol with various aromatic aldehyde derivatives under solvent-free condition. The synthesized zeolite H-Zeolite A was characterized by XRD, SEM, and FT-IR. The synthesized products were characterized by FT-IR and 1H-NMR spectra. Simple workup procedure, short reaction time, high yield, and reusability of the catalyst are the characteristic features of these reactions.
The main objective of this paper is to analyze and compare the color strengths of mercerized and unmercerized fabric among different fabric structures. In this research work Remazol reactive dye and three types of woven fabrics were used such as 20⁎20 sheeting, 30⁎30 sheeting, and herringbone. Spectrophotometer was used to find out the amount of dye which is fixed in the fabrics after soap wash. Three different woven fabrics were dyed with reactive dye (Remazol Red, Remazol Yellow, and Remazol Blue) using pad dyeing method. It was found that mercerized fabric had higher depth of shade under the same dye concentration. In case of shade A (0.5%) 20⁎20 sheeting showed better color strength compared to other two structures but for shade B (1.5%) and shade C (4%) herringbone fabric showed better dye absorptive capacity than 20⁎20 sheeting.
The growth and properties of cadmium sulfide (CdS) thin films were prepared in a controlled manner using chemical bath deposition (CBD) method for different KMnO4 activation time such as 5 min, 10 min, 15 min, 20 min, 25 min, and 30 min on glass substrates. CdS thin films are deposited on KMnO4 activated glass substrates at 85°C with pH value of 10 for 30 min deposition time. In the chemical bath deposition (CBD) technique, KMnO4 activation time plays an important role in the growth of the CdS film. The structure of the CdS film changes with respect to the rate of deposition. The size of the particles is affected by the nucleation rate if the solution does not contain the constant number of Cd2+ and S2− ions throughout the deposition process. This change in structure of CdS is confirmed by the XRD, SEM, and AFM analysis, and the ion-by-ion nucleation growth is also examined. The optical property of the prepared CdS thin film is scrutinized using UV-Vis-NIR absorption analysis.
A new intercalation compound of insect pheromone, valeric acid (VA), based on zinc layered hydroxide (ZLH) as host release material, was successfully prepared through coprecipitation method. The as-produced organic-inorganic nanolayered material, valerate nanohybrid, VAN, shows the formation of a new peak at lower 2θ angle with basal spacing of 19.8 Å with no ZnO reflections, which indicate that the intercalation of anion between the inorganic ZLH interlamellae was accomplished. The elemental, FTIR, and ATR analyses of the nanohybrid supported the fact that the intercalation with the percentage anion loading was calculated to be 23.0% (w/w). The thermal stability property of the resulting nanohybrid was enhanced compared to the unbound anion. Field emission scanning electron micrograph of the ZnO has a nonuniform granular structure but transforms into flake-like structure with various sizes after the intercalation process. Release kinetics of anion from the interlayer of intercalated compound exhibited a slow release behavior governed by the pseudo-second-order kinetic model at different pHs of aqueous media. The valerate anion was released from VAN with the highest release rate at pH 4. These findings provide the basis to further development of controlled release formulation for insect pheromone based on ZLH intercalation.
In this investigation, static fracture, microstructure, and the mechanical behavior of SP-700 alloy (a superplastic grade) were evaluated and compared with two other titanium alloys. The comparisons were made in terms of suitably designed heat treatment cycles. The heat treatment cycles included annealing and a combination of solutionizing and aging treatments for all three alloys. Tensile properties were determined using MTS Landmark Servohydraulic Test System. Tensile tested samples’ fracture surfaces were investigated with LEO-VP SEM instrument. Ti-15-3-3-3 alloy exhibited relatively a higher combination of strength and ductility in comparison to the other two alloys. All three types of titanium alloys demonstrated a very good level of tensile strength and ductility suitable for applications in military and biomedical fields.
The experimental study of water vapour adsorption phenomenon on a zeolite, by dielectric relaxation measurement, makes it possible to determine the variations in the exchangeable cation hopping activation energy, on the surface of the solid, in relation to the number of adsorbed molecules. The present work shows that it is possible to explain the change observed in the energy, by means of simple assumptions based, on the one hand, on the models used in order to simulate the adsorption process and, on the other hand, on the distribution of the molecules adsorbed near the exchangeable cations. Thus, the phenomenological interpretation suggested here, about the change in the exchangeable cation hopping energy, obtained by dielectric relaxation measurement, makes us with a mind to conceive a simple method for explaining the results leading to new information on the organization of the first adsorbed molecules on the surface of the studied zeolite. Then, it can be verified that these conclusions confirm the assumptions already developed for interpreting the inferences from previous experiments carried out by means of other techniques.
The nc-AlTiN/Si3N4, TiAlN, and TiN coating were deposited using lateral rotating cathodes (LARC) technology on TNMG 160404 cemented carbide turning inserts. Ultrafine grain treated cemented carbide substrates were used in case of TiAlN and TiN inserts. The coated inserts were tested for their hardness and compositions were determined by X-ray diffraction studies. The grain structures of coatings were observed using scanning electron microscopy. Dry cutting tests were performed on AISI 304 stainless steel to compare the performances of these coatings in terms of wear and surface finish imparted to workpiece. 3D confocal laser microscope was used to determine the flank wear. Grey relation analysis was carried out to optimize the machining parameters. Studies reveal that nc-AlTiN/Si3N4 coating showed the highest hardness of 28 GPa. The coating also shows a dense grain structure. Furthermore, in cutting tests even under severe dry cutting conditions, the wear observed was less than the other two coatings and surface finish imparted to work parts was less than 2 μm by this coating.
Cobalt ferrite (CoFe 2 O 4 ) and silica (SiO 2 ) nanopowders have been prepared by the microwave hydrothermal (M-H) method using metal nitrates as precursors of CoFe 2 O 4 and tetraethyl orthosilicate as a precursor of SiO 2 . The synthesized powders were characterized by XRD and FESEM. The (100-x) (CoFe 2 O 4 ) + xSiO 2 (where x = 0%, 10%, 20%, and 30%) composites with different weight percentages have been prepared using ball mill method. The composite samples were sintered at 800°C/60 min using the microwave sintering method and then their structural and morphological studies were investigated using X-ray diffraction (XRD), Fourier transformation infrared (FTIR) spectra, and scanning electron microscopy (SEM), respectively. The effect of SiO 2 content on the magnetic and electrical properties of CoFe 2 O 4 /SiO 2 nanocomposites has been studied via the magnetic hysteresis loops, complex permeability, permittivity spectra, and DC resistivity measurements. The synthesized nanocomposites with adjustable grain sizes and controllable magnetic properties make the applicability of cobalt ferrite even more versatile.
The present paper discusses the aspects of the synthesizing valeric acid based poly(ether sulfone)s with active carboxylic acid pendants (VALPSU) from solution polymerization technique via nucleophilic displacement polycondensation reaction among 4,4′-dichlorodiphenyl sulfone (DCDPS) and 4,4′-bis(4-hydroxyphenyl) valeric acid (BHPA). The conditions necessary to synthesize and purify the polymer were investigated in some detail. The synthesized poly(ether sulfone)s comprise sulfone and ether linkages in addition to reactive carboxylic acid functionality; these active carboxylic acid functional groups were exploited to hold the phenyl sulphonic acid and phenyl phosphonic acid pendants. The phenyl sulphonic acid pendants in VALPSU were easily constructed by altering active carboxylic acid moieties by sulfanilic acid using N,N′-dicyclohexylcarbodiimide (DCC) mediated mild synthetic route, whereas the latter one was built in two steps. Initially, polyphosphoric acid condensation with VALPSU by 4-bromoaniline and next straightforward palladium catalyzed synthetic route, in both of which acidic pendants are clenched by polymer backbone via amide linkage. Without impairing the primary polymeric backbone modified polymers were prepared by varying the stoichiometric ratios of respective combinations. All the polymers were physicochemically characterized and pressed into tablets; electrical contacts were established to study the dielectric properties. Finally, the influence of the acidic pendants on the dielectric properties was examined.
Aerogels are a series of materials with porous structure and light weight which can be applied to many industrial divisions as insulators, sensors, absorbents, and cushions. In this study, cellulose-based aerogels (aerocelluloses) were prepared from cellulosic material (microcrystalline cellulose) in sodium hydroxide/water solvent system followed by supercritical drying operation. The average specific surface area of aerocelluloses was 124 m 2 /g. The nitrogen gas (N 2 ) adsorption/desorption isotherms revealed type H1 hysteresis loops for aerocelluloses, suggesting that aerocelluloses may possess a porous structure with cylindrically shaped pores open on both ends. FTIR and XRD analyses showed that the crystallinity of aerocelluloses was significantly decreased as compared to microcrystalline cellulose and that aerocelluloses exhibited a crystalline structure of cellulose II as compared to microcrystalline cellulose (cellulose I). To perform cationic functionalization, a cationic agent, (3-chloro-2-hydroxypropyl) trimethylammonium chloride, was used to introduce positively charged sites on aerocelluloses. The cationized aerocelluloses exhibited a strong ability to remove anionic dyes from wastewater. Highly porous and low cost aerocelluloses prepared in this study would be also promising as a fast absorbent for environmental pollutants.
Most recent history shows that polytetrafluoroethylene (PTFE) is widely used as antifrictional materials in industry for wide speed range. A high antifriction property of PTFE makes it suitable for dry friction bearing. Main disadvantage of using PTFE is its high wear rate, so extensive research had been carried out to improve the wear resistance with addition of filler material. This study focuses on four input parameters load, sliding speed, sliding distance, and percentage of glass fiber as a filler material. Taguchi method was used for experimentation; each parameter is having 3 levels with L27 orthogonal array. Grey relational analysis is used to convert multiple response parameters, namely, wear and coefficient of friction, into single grey relation grade. The optimal input parameters were selected based on the S/N ratio. It was observed that load 3 kg, sliding speed 5.1836 m/s (900 rpm), sliding distance 2 km, and 15% of glass fiber are optimal input parameters for PTFE without significantly affecting the wear rate and coefficient of friction.
