Showing papers in "Materials today communications in 2020"
TL;DR: A general understanding is provided of how various properties of nanoparticles aid in drug delivery through BBB and usher the development of novel nanotechnology-based nanomaterials for cerebral disease therapies.
Abstract: The Blood-Brain Barrier (BBB), a unique structure in the central nervous system (CNS), protects the brain from bloodborne pathogens by its excellent barrier properties. Nevertheless, this barrier limits therapeutic efficacy and becomes one of the biggest challenges in new drug development for neurodegenerative disease and brain cancer. Recent breakthroughs in nanotechnology have resulted in various nanoparticles (NPs) as drug carriers to cross the BBB by different methods. This review presents the current understanding of advanced NP-mediated non-invasive drug delivery for the treatment of neurological disorders. Herein, the complex compositions and special characteristics of BBB are elucidated exhaustively. Moreover, versatile drug nanocarriers with their recent applications and their pathways on different drug delivery strategies to overcome the formidable BBB obstacle are briefly discussed. In terms of significance, this paper provides a general understanding of how various properties of nanoparticles aid in drug delivery through BBB and usher the development of novel nanotechnology-based nanomaterials for cerebral disease therapies.
157 citations
TL;DR: In this article, the thermal and mechanical properties of bamboo fiber reinforced composite (BFRC) derived from Gigantochloa scortechinii were analyzed using a thermogravimetric analysis and differential scanning calorimetric.
Abstract: This paper presents the thermal and mechanical properties of bamboo fiber reinforced composite (BFRC) derived from Gigantochloa scortechinii. The bamboo fibers were prepared through chemical treatment by sodium hydroxide (NaOH) followed by physical milling method. The thermal characteristics of the bamboo fiber and its polymer composite were analysed using a thermogravimetric analysis and differential scanning calorimetric. The functional groups and crystallinity of the fiber were analysed with Fourier transform infrared and x-ray diffraction spectroscopy. Meanwhile, the fiber morphology was examined using a scanning electron microscope. The BFRCs with fiber volume fractions ranging from 0 % to 40 % embedded in three thermoset resins (epoxy, polyester, vinyl ester) were subjected to tensile and flexural tests and the fracture pattern was examined. The NaOH concentration of 10 % with soaking duration of 48 h was found to produce a bamboo fiber with the highest ultimate tensile and modulus strength. The tensile and flexural properties of all the BFRCs were found to be directly proportional to the fiber volume fractions. It was found that the bamboo fiber reinforced epoxy composite (BFREC) with 40 % fiber volume fraction exhibited the highest tensile and flexural strength compared to polyester and vinyl ester composites. The method of bamboo fiber composite preparation in this work may serve as a useful guide to produce a strong BFRC for external strengthening of buildings and structures.
130 citations
TL;DR: In this paper, a review of the characterization techniques, synthesis approaches and properties of carbon nanotubes (CNTs), reported by earlier researchers in the past, is presented.
Abstract: Since their first synthesis, carbon nanotubes (CNTs) gained remarkable research interest owing to their astonishing mechanical properties and extensive range of potential applications in various sectors, such as aerospace, automobile, biomedical, defence, energy, etc. This paper covers numerous characterization techniques, synthesis approaches and properties of the CNTs, reported by earlier researchers in the past. The technological and industrial needs for the development of lightweight nanocomposites have led to the significant advancements in the preparation of CNT-reinforced composites. In preliminary sections, the properties and applications of the CNT-reinforced nanocomposites are elaborated along with the issues related to their preparation. Here, various nanotubes synthesis processes, such as arc discharge, laser ablation and chemical vapour deposition, are exemplified with the support of published works. Furthermore, we have also addressed the several surface modification techniques of CNTs, such as purification, functionalization and dispersion, which make this review novel and exhaustive. In order to address the limitations and challenges incurred during the preparation of various CNT-reinforced polymer/metal matrix composites, an extensive collection of the published literature is reported and discussed, thoroughly. Based on this exhaustive review, some specific observations are made which would facilitate upcoming researches to explore the research opportunities in the preparation of CNTs and CNT-reinforced composites and their potential applications for the high-performance structures/components.
99 citations
TL;DR: This review provides an overview of how different attributes, such as chemical nature, size, shape, surface charge, topography, stiffness, and functional features of nanomaterials, influence the cell-nanomMaterials interactions.
Abstract: The utilization of nanomaterials in the biological and medical field is quickly progressing, particularly in areas where traditional diagnostics and treatment approaches have limited success. The success of nanomaterials in medical products such as biomedical implants, wound dressings and drug delivery systems rely upon their effective interaction between the extracellular matrix, cells, and intracellular components. Upon contact with mammalian cells, nanoparticles (NPs) begin to interact with the extracellular matrix, cell membrane, cytoplasmic proteins, nucleus, and other cellular organelles, which result in nanoparticle internalization and subsequent cellular responses. Such responses elicited by the mammalian cells as a result of the cell-nanomaterials interactions, both at the cellular and molecular level, are mainly determined by the morphological, chemical, and surface characteristics of the nanomaterials themselves. This review provides an overview of how such different attributes, such as chemical nature, size, shape, surface charge, topography, stiffness, and functional features of nanomaterials, influence the cell-nanomaterials interactions.
89 citations
TL;DR: In this article, the progress reported in the literature where slot-die coating has been used for the deposition of both the perovskite layer and other layers in the solar cell device stack is discussed.
Abstract: To make perovskite solar cells an industrially relevant technology large area deposition techniques are needed and one of the most promising is slot-die coating. This review article details the progress reported in the literature where slot-die coating has been used for the deposition of both the perovskite layer and other layers in the perovskite solar cell device stack. An overview of the methods used to adapt the coating process, materials and drying conditions in order to create high quality layers and devices is given and an outlook on future research directions in this field is made.
84 citations
TL;DR: In this paper, the authors discuss the requirements of BTE scaffolds and highlights the important role of additive manufacturing (AM) technologies in building bridges between biomaterials, CAD models and additives, and bone tissue engineering scaffolds.
Abstract: Large bone defects, which occur due to various causes, have substantially affected people's health and quality of life. Bone tissue engineering (BTE) is a promising approach for repairing or replacing bone injuries. The aim of BTE scaffolds is to mimic the biological function and structure of the natural bone extracellular matrix (ECM), which provides a three-dimensional (3D) environment for cell adsorption, proliferation and differentiation. Significant advances in materials science, computer-aided design (CAD) and biomedical engineering have facilitated BTE scaffolds. This paper describes the requirements of BTE scaffolds and highlights the important role of additive manufacturing (AM) technologies in building bridges between biomaterials, CAD models and additives, and BTE scaffolds. It reviews various AM technologies that are used to fabricate BTE scaffolds. These technologies are divided into seven categories: (1) stereolithography (SLA), (2) powder bed fusion (PBF), (3) binder jetting (BJ), (4) material extrusion (ME), (5) material jetting (MJ), (6) volumetric printing (VP) and (7) 4D printing (4DP). The characteristics, raw materials, accuracy, cost, advantages and disadvantages of the AM technologies are discussed. Several recommendations for future research are presented.
79 citations
TL;DR: In this paper, a simple and rapid electrochemical biosensor based on delaminated titanium carbide MXene (d-Ti3C2TX MXene) and multi-walled carbon nanotubes (MWCNTs) composite including molecularly imprinted polymers (MIPs) was formed for amyloid-β having 42-amino-acid-peptide (Aβ42) protein sensing.
Abstract: Amyloid β-protein, a polypeptide, is known as the reason of neuronal death and is widely recognized as a biomarker of Alzheimer's disease. In this study, a simple and rapid electrochemical biosensor based on delaminated titanium carbide MXene (d-Ti3C2TX MXene) and multi-walled carbon nanotubes (MWCNTs) composite including molecularly imprinted polymers (MIPs) was formed for amyloid-β having 42-amino-acid-peptide (Aβ42) protein sensing. After d-Ti3C2TX/MWCNTs composite was prepared by mixing the colloidal solution of d-Ti3C2TX MXene with MWCNTs (mass ratio 3:1), some analytic methods such as x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), UV/Vis spectroscopy, atomic force microscopy (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed for characterizations of d-Ti3C2TX MXene, MWCNTs and d-Ti3C2TX/MWCNTs composite. Later, Aβ42 imprinted d-Ti3C2TX/MWCNTs/GCE was prepared in a mixture including 100.0 mM pyrrole (monomer) containing 25.0 mM Aβ42 (template) in phosphate buffer (0.1 M, pH 7.5) by CV method for 25 cycles. Aβ42 imprinted electrode showed a linear range of 1.0 fg mL−1 - 100.0 fg mL-1 and detection limit (LOD) of 0.3 fg mL-1 were obtained. Aβ42 imprinted electrode was examined in terms of stability, repeatability, reproducibility and reusability. Finally, Aβ42 imprinted biosensor was applied to plasma samples for Aβ42 analysis.
79 citations
TL;DR: In this article, a reentrant arc-shaped honeycomb (RAH) model is proposed to improve the impact energy absorption abilities and maintain good crushing load uniformity of auxetic honeycombs, and the in-plane impact resistances and absorbed-energy characteristics of bio-inspired auxetic RAHs are numerically studied by using ABAQUS/EXPLICIT.
Abstract: In order to improve the impact energy absorption abilities and maintain good crushing load uniformity of auxetic honeycombs, a re-entrant arc-shaped honeycomb (RAH) model is proposed according to the concept of bio-inspired structure design. The in-plane impact resistances and absorbed-energy characteristics of bio-inspired auxetic RAHs subjected to a constant velocity crushing are numerically studied by using ABAQUS/EXPLICIT. It is shown that due to the introduction of re-entrant arc-shaped structures, the dynamic response curves of bio-inspired RAHs have better crushing load uniformity than conventional re-entrant honeycombs. Except for the relative density and impact velocity, the dynamic crushing behaviors of bio-inspired RAHs also depend upon the cell micro-structure parameters (e.g., the curvature). Based on the one-dimensional (1D) shock theory and absorbed-energy efficiency method, an empirical equation is deduced to evaluate the dynamic plateau stress of bio-inspired RAHs. The finite element (FE) results coincide well with those calculated by the empirical formulas. Moreover, the specific energy absorption (SEA) and energy dissipation rules of bio-inspired RAHs are discussed, which are also dependent on the curvature. These researches will provide technical support for the innovative structure design and dynamic optimization design of auxetic cellular structures.
66 citations
TL;DR: In this paper, a mini-review of the wet-chemical methods of preparing MoS2 and their electrochemical properties were summarized, and it was suggested that the modified methods of preparation and appropriate composite materials can enhance the supercapacitor properties of MoS 2 based materials.
Abstract: Molybdenum-based supercapacitors, a fast promising area where researchers are exploring the possibilities of improving the performance of its electrode materials and their derivatives for energy storage. Molybdenum sulfide (MoS2) has attracted considerable interest because of its superior properties as a supercapacitor-based material. In this mini-review, the wet-chemical methods of preparing MoS2 and their electrochemical properties were summarized. The preparation methods and their composite substrates of MoS2 based supercapacitors have been highlighted to be one of the determining factors for improving the electrochemical output being reported. This review suggested that the modified methods of preparation and appropriate composite materials can enhance the supercapacitor properties of MoS2 based materials. Finally, we explore the future opportunities for advance storage potential presented by MoS2 based materials.
62 citations
TL;DR: Nanofiltration (NF) has emerged as a potentially superior and cost-effective way to remove sediments, charged particles, chemical effluents, bacteria and other pathogens in addition to removal of toxins like arsenic or impurities such as oils.
Abstract: Nanofiltration (NF) has emerged as a potentially superior and cost-effective way to remove sediments, charged particles, chemical effluents, bacteria and other pathogens in addition to removal of toxins like arsenic or impurities such as oils. Important properties intrinsic to NF membranes include high permeation to monovalent ions, low permeation to divalent ions and higher flux than reverse osmosis membranes. In addition, NF membranes offer advantages over other membranes due to increased reliability and integrity, producing longer cycle times and hence lower costs. Due to these characteristics, NF membranes have been used in a wide range of applications, including water treatment, agri-food, biotechnology and pharmaceutical industries. In this review, we present some of the most recent and impactful advances in NF area, detailing new membrane materials and processes as well as their new potential applications. The future developments of NF uses, involving new 2-dimensional (2D) nanomaterials, such as graphene, graphene oxide, boron nitride (BN) and atomic layered transition metal dichalcogenides (TMDs), are also discussed.
61 citations
TL;DR: In this paper, the packing characteristics of polydisperse hard particle beds and the determination of the expected density achievable for a given particle size and shape distribution were investigated for discrete mixtures as well as continuous distributions.
Abstract: Several additive manufacturing (AM) methods use powder feed materials. Selective laser sintering is an example of a versatile AM method, using feed material in powder form, capable of producing polymer and metallic parts. In the variations of this technique, a laser spot or an electron beam is used to locally sinter or melt a packed powder bed. After the completion of sintering on each layer, further powder is added on top of the existing bed so that the next layer may be joined. A major challenge in this method is controlling the porosity of the powder bed so that the final part has uniform and maximum density. Uniformity in the packing of bed from one layer to the other is important for optimizing the processing parameters. This review is focused on considering the packing characteristics of polydisperse hard particle beds and the determination of the expected density achievable for a given particle size and shape distribution. Models are presented for discrete mixtures as well as continuous distributions. The effect of the initial configuration of a particle bed on its ability to form a highly dense packing is also discussed. Blending of different particle sizes and shapes can be used to substantially increase the packing density, but can also lead to separation or segregation of the bed. Through appropriate control of the particle shape and use of wide distributions, packing densities close to 100 % can theoretically be achieved, but practicality and various effects that appear at small size scales prevent from achieving such high packing densities. Recent advancements have reduced the dependence of AM part quality on the density of the packed particle bed but the packing is still important for considerations such as thermal conductivity of the bed and absorption of laser power in the bed. Improved knowledge of packed bed characteristics can be helpful in developing AM methods for novel material systems.
TL;DR: In this paper, melanin nanoparticle (MNP) reinforced cellulose nanofiber (CNF) based nanocomposite films were extracted using a combination of chemical and physical methods.
Abstract: The featured work reports the preparation, characterization and various properties of melanin nanoparticle (MNP) reinforced cellulose nanofiber (CNF) based nanocomposite films. The CNF was extracted using a combination of chemical and physical methods. The MNP was isolated from a natural source sepia ink by following a simple centrifugation technique and used as a functional nanofiller to fabricate the CNF/MNP nanocomposite films. The prepared nanocomposite films were characterized in terms of morphology, structure, chemical interactions, optical properties, surface hydrophobicity, mechanical properties, thermal stability and antioxidant activity. The MNP was shown to be evenly dispersed in the CNF matrix and biocompatible with cellulose matrix to form the nanocomposite films. Incorporation of MNP enhanced the ultraviolet blocking, mechanical properties, hydrophobicity and water vapor barrier properties of the nanocomposite films. The developed nanocomposite films also showed strong antioxidant activity. The crystalline structure, crystallinity and thermal stability of the nanocomposite films were not affected meaningfully. The sepia ink isolated MNP has a very good prospective to be used as a nanofiller for the preparation of CNF based nanocomposite films.
TL;DR: In this paper, a review of GO reinforced epoxy resins is presented, where they can be classified into two broad groups: epoxy/GO nanocomposites and epoxy-GO coatings, depending on the application types.
Abstract: Compared to graphene, graphene oxides (GO) have also been applied in many areas due to their unique structures and properties, such as tunable and functionalized surfaces, great processing and competition for scalable production. In this review, GO reinforced epoxy resins are systematically looked into, where they can be classified into two broad groups: epoxy/GO nanocomposites and epoxy/GO coatings, depending on the application types. In the epoxy/GO nanocomposites, the GO reinforcement on the different properties of epoxy matrices are described in details, like mechanical, toughness, thermal conductivity and so on. As for the epoxy/GO coatings, the GO effect on the anti-corrosion properties is one of the main concerns. For both of them, GO modification methods and dispersing routes in the respective epoxy matrices are among the most important considerations. There are some remaining unsolved issues, which will be highlighted together with the future perspectives of the GO reinforced epoxy resins.
TL;DR: Current advances in acellular 3D printed scaffolds, proper microporous structure and geometry for bone repair, and suitable materials for 3D printing the regenerative bone substitutes are explained.
Abstract: Bone injuries can be treated using tissue engineering scaffolds, but the conventional constructs have a big challenge in supplying requirements of native tissue, i.e., bioactivity potential, mechanical stability, controllable biodegradability, and proper cellular interaction. In this regard, 3D printing technology with the possibility of controlling the internal microstructure and geometry of synthesized matrixes was introduced as a promising approach for bone defect regeneration. Although a variety of novel materials, which have shown initial potential for bone repair, can be used for preparing the biocompatible matrixes, the 3D printer type and selecting an innovated technology depend on the properties of applied biomaterials. In all the used methods, tunable, controllable, and interconnected porous microstructure can be fabricated even though identification of suitable porosity and microstructure, which can supply required mechanical properties of natural bone and support cellular adhesion, proliferation, and differentiation, need to evaluate. Therefore, this mini-review explains current advances in acellular 3D printed scaffolds, proper microporous structure and geometry for bone repair, and suitable materials for 3D printing the regenerative bone substitutes. Herein, the novel and recent studies were focused and probable limitations, and existing strategies were discussed.
TL;DR: These results demonstrated that these facile nanomaterials are promising antibacterial and antibiofilm agents that can be utilized to inhibit the growth of human bacterial pathogens associated with chronic infections.
Abstract: Due to the globally identified antibiotic resistance among clinical bacteria, novel antibacterial materials are needed to circumvent drug resistance. In this study, we report a facile synthesis method for the fabrication of a uniform silver (I) oxide (Ag2O) garnished graphene oxide (GO) nanocomposite (Ag2O/GO) using sonication and characterized them by X-ray diffraction (XRD), Raman spectroscopy, and UV–vis spectroscopy. Furthermore, the antibacterial properties of Ag2O, GO, and Ag2O/GO nanocomposite were studied using drug resistant Gram-negative Escherichia coli (ESBL), Pseudomonas aeruginosa (ESBL), Klebsiella pneumoniae and Gram-positive Staphylococcus aureus by well diffusion assay, colony forming ability, and cell membrane permeability assay. The nanocomposite (15.62−1000 μg/mL) showed excellent antibacterial activity with minimum inhibitory concentration of 125 μg/mL for P. aeruginosa and K. pneumoniae; 62.5 μg/mL for E. coli, and 250 μg/mL for S. aureus. Biofilm inhibition assay revealed the inhibition of biofilm formation in a dose related manner. Inhibition of biofilm formation by ½ MIC and MIC of Ag2O and Ag2O/GO against four pathogenic and biofilm forming bacteria was found statistically significant as P ≤ 0.05 (at ½ MIC) and P ≤ 0.01 (at MIC). These results demonstrated that these facile nanomaterials are promising antibacterial and antibiofilm agents that can be utilized to inhibit the growth of human bacterial pathogens associated with chronic infections.
TL;DR: In this paper, a review of the different methods to improve interlaminar interfaces in laminated composites, including their performances and drawbacks, as well as the future trends in the related topics is presented.
Abstract: Interlaminar fracture or delamination is one of the major failure modes for fiber reinforced polymer (FRP) and fiber metal laminate (FML) composites. Many studies have been carried out to investigate the mechanisms affecting this interlaminar failure and ways to improve the interlaminar fracture toughness (ILFT) of FRP composites and FMLs. However, information on the topic is scattered, with studies having different emphases. Therefore, in this review, the studies are surveyed and put into perspective in terms of the improvements to ILFT achieved. A wide range of methods to improve the ILFT of FRP composites and FMLs is presented. For FRP composites, the methods include modifications to the constituents or interlaminar regions of the composite, applications of nano-fillers in multiscale composites approaches, and through thickness reinforcement techniques. For FMLs, studies on various surface treatment methods for the metal in FMLs are included. The strengthening mechanisms involved in each of the methods are also discussed. This review provides a comprehensive picture of the different methods to improve interlaminar interfaces in laminated composites, including their performances and drawbacks, as well as the future trends in the related topics.
TL;DR: Polythiophene doped ZnO (PTh/ZnO) photocatalysts with various weight percentages of PTh (1-10%) were synthesized via modified sol-gel and oxidative polymerization techniques.
Abstract: The present work aims to enhance the photocatalytic performance of mesoporous ZnO by doping with polythiophene (PTh) for the treatment of toxic pollutants. Polythiophene doped ZnO (PTh/ZnO) photocatalysts with various weight percentages of PTh (1–10%) were synthesized via modified sol-gel and oxidative polymerization techniques. The XRD patterns revealed a well-crystalline hexagonal wurtzite phase of ZnO, whereas the XPS, FTIR and Raman spectra confirmed the successful coupling between PTh and ZnO nanostructures. TEM results illustrate the uniform distribution of PTh onto the mesoporous ZnO. UV–vis spectroscopy revealed a small lowering in bandgap energies upon PTh incorporation. The prepared PTh/ZnO nanostructures have been successfully exploited for the photocatalytic degradation of methylene blue dye (MB) and gemifloxacin mesylate (GFM) antibiotic. All doped samples exhibited superior performances in comparison to either pure PTh or undoped ZnO. The 5% PTh/ZnO showed the highest activity with 95 % degradation efficiency of MB dye in 180 min of irradiation with rate constant value 0.0156 min−1 which is almost 2.6 higher than pure ZnO. In addition to this, 5% PTh/ZnO proven to be highly active towards the degradation of gemifloxacin mesylate antibiotic after 180 min of irradiation time, yielding ∼80 % degradation efficiency. Repeated cyclic use of the current photocatalyst indicated excellent reusability and operational stability. The reaction mechanism involved during the photocatalytic degradation is also proposed.
TL;DR: In this article, a sol-gel technique was applied to synthesize mesoporous silica (MPSS) SBA-15 and modify it to magnetic mesoporus (MMPS) Fe3O4/SBA-2015.
Abstract: In this work, a sol-gel technique was applied to synthesize mesoporous silica (MPSS) SBA-15 and modify it to magnetic mesoporous (MMPS) Fe3O4/SBA-15. The surface engineering modification was implemented according to the incipient wetness impregnation (IWI) method to create specific magnetic sites adsorbent for loading and release of Meloxicam (MEL). The MPSS and MMPS were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FT-IR), BET surface area, and thermal gravimetric analysis (TGA). Four parameters were investigated: pH, concentration of drug, dose of carriers, and contact time. The maximum drug loading efficiencies (DL%) on SBA-15 and Fe3O4/SBA-15were 31.81 % and 42.85 % respectively. The MEL released was studied in phosphate buffer solution (PBS) at pH 7.4. The release of MEL from SBA-15 and Fe3O4/SBA-15 after 18 and 24 h was 85.76 % and 78.13 % respectively. Freundlich adsorption isotherm was the most acceptable for the two carrier’s SBA-15 and Fe3O4/SBA-15. The kinetics models for the drugs release fitted well with the first order kinetic model. The drug loading process was investigated in a batch system by implementation of experimental design technique. The objective function (response) was the drug loading efficiency (DL%). A response surface method (RSM) was applied to define the optimum and significant factors that affect the drug loading process.
TL;DR: In this article, the authors presented the self-healing performance of cracks in strain-hardening cement-based composites (SHCCs) containing different amounts of magnesia expansive agents (MEAs) with different reactivities.
Abstract: This contribution presents the self-healing performance of cracks in strain-hardening cement-based composites (SHCCs) containing different amounts of magnesia expansive agents (MEAs) with different reactivities Specimens were preloaded under a four-point bending test to induce cracks and then exposed to water fog curing conditions The changes in the crack width before and after curing were measured with a digital microscope, and a water absorption test was also performed to measure the sealing ability of the cracks The test results show that three reactive MgO expansive agents can significantly improve the crack healing efficiency of SHCC under water fog curing conditions However, the self-healing effect of the 10 % dosage was not as good as that of the 5% dosage when the reactivity of the MEA was the same, and the MgO expansive agent with a reactivity value of 110 s shows the most promising effect on crack healing Moreover, it should be noted that the 10 % dosage was too high for the 110 s MgO expansive agent, resulting in poor volume stability
TL;DR: In this paper, the authors investigated the effect of processing parameters on friction stir welding of polycarbonate (PC) and found that higher heat inputs increased the volume of the preheated material in front of the FSW tool and extruded the material from the leading edge into leading edge.
Abstract: Friction stir welding (FSW) of thermoplastic materials is an attractive but a challenging process due to inherent chemical and mechanical characteristics of polymeric materials. In the present work, thermo-mechanical models were employed to investigate the effect of processing parameters on of FSW of polycarbonate (PC). The heat flux during the joining process was localized around the PC join line and led to the formation of circular rings on the upper surface. According to the simulation results, increasing the tool rotational velocity reduced the temperature gradient and decfeased the suseptibelity of crack formation around the joint line. Cracks were formed at low frictional heats and high strain rates during material stirring. On the other hand, higher heat inputs increased the volume of the preheated material in front of the FSW tool and extruded the material from the leading edge into leading edge. Consequently, less crackes were formed as the plasticized material filed SZ. The results can be used to establish more robust processing parameters for FSW of polymers.
TL;DR: In this paper, a prominent Southeast Asian flowering plant species (M. kobus) was investigated for its inhibition efficiency against mild steel corrosion in 1 1/M H2SO4.
Abstract: Magnolia kobus DC. (M. kobus), a prominent Southeast Asian flowering plant species, was investigated for its inhibition efficiency against mild steel corrosion in 1 M H2SO4. The extract (M. kobus) was identified to have 145.80 μg/g of myricetin and 102.32 μg/g syringic acid as prominent components, with a total phenolic content (TPC) of 95.26 mg/g and a total flavonoid content (TFC) of 25.38 mg/g. The mass-loss measurements showed that 500 ppm of M. kobus extract was able to inhibit corrosion, with an efficiency of 95.01% at 303 ± 1 K. Reduction of dissolved iron content in the inhibited solution than in the inhibitor free solution observed in Atomic Adsorption Spectroscopy (AAS) revealed the corrosion mitigating effect of inhibitor on mild steel. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) analysis of the protected and unprotected mild steel samples indicate adsorption of M. Kobus on the electrode surface. UV–vis and FT-IR studies complement the above results. The electrochemical studies indicated that M. kobus functioned as a mixed-type indicator and myricetin along with other plant components present in the plant extract contributed to the inhibition process.
TL;DR: In this paper, the authors highlighted the recent applications and challenges of graphene and its derivatives in stem cell proliferation, bone tissue engineering, neuronal proliferation and in biosensors, and also enlisted the recent advancements of graphene as anticancer therapy and targeted drug delivery system.
Abstract: The peculiar features of graphene like excellent physicochemical, electrical, large surface area and biocompatibility are revealing through the past decade, leading to continuous research on the use of graphene nanomaterial in various clinical applications and regenerative medicine. In this review, we highlighted the recent applications and challenges of graphene and its derivatives in stem cell proliferation, bone tissue engineering, neuronal proliferation and in biosensors. Graphene or graphene oxide has shown interesting results in angiogenesis, neuronal regeneration and immunomodulation in various in vitro and in vivo studies. Graphene based materials have a potential to be emerging as next generation nanomaterials. We discussed about the conventional procedures and related challenges in synthesis of graphene oxide. This review aims in summarizing the recent progresses of various graphene based nanomaterials and their hybrids in biomedical applications. Graphene as two dimensional, three dimensional and hybrids are attracting interest in biosensing and bioimaging. However, besides the fascinating properties of graphene, its biocompatibility and biodegradability related toxicities are still a question to researchers. Graphene nanomaterials use in various tissue scaffolds should be taken as an active area of interest by the researchers in near future. This review also enlisted the recent advancements of graphene as anticancer therapy and targeted drug delivery system. We hope the summary of this review inspires the researchers to conduct more studies on graphene based applications and its possible toxicities in humans, so that it can be implemented as cost effective and safe treatment to many pathological conditions.
TL;DR: In this paper, a simplified image quality metric is proposed for X-ray microtomography, which is sensitive to all typical microCT scan errors and artifacts, which makes it a valuable tool for defining a required minimum image quality for an analysis.
Abstract: X-ray microtomography is widely used in materials science and engineering applications for imaging and analysis of material structure and morphology. For this purpose, and especially in the case of routine analysis tasks for industrial materials applications, confidence in obtained measurement results are crucial. Despite great progress in this field over the last 10 years, with many high-quality commercial systems now available, the lack of a simple and widely-used image quality metric that can capture all important aspects of the quality of a microCT scan, continues to hinder wider acceptance of the technology. Various errors can occur during the microCT scan process, which can potentially mask the presence of pores, or affect the volumetric measurements of interest. In this work we demonstrate a simplified image quality metric which can easily be implemented. We show how this new image quality metric is sensitive to all typical microCT scan errors and artifacts, which makes it a valuable tool for defining a required minimum image quality for an analysis. The object used is a 10 mm cube of titanium alloy (Ti6Al4V) produced by laser powder bed fusion additive manufacturing. This type of coupon sample is useful for analysis of the additive manufacturing process, but it is critical that small pores are seen with good contrast. Identical porosity analysis workflows are applied to scans with different image qualities, which demonstrates the importance of image quality for reproducible analyses of this sample type. The results have implications in defining quality values for all forms of materials analysis using the technique. This work can further lead the way to incorporating microCT into future fully automated and standardized analysis workflows for quality control, when image quality meets a specified minimum criterion.
TL;DR: In this paper, a bisbenzylidene cyclopentanone and cyclohexanone-functionalized polybenzoxazine nanocomposites were used as anti-corrosion coatings.
Abstract: In this study, we synthesized and investigated bisbenzylidene cyclopentanone and cyclohexanone-functionalized polybenzoxazine nanocomposites as anti-corrosion coatings. The chemical structures of CP-BZ and CH-BZ were confirmed using Fourier transform infrared (FTIR) spectroscopy and 1H and 13C nuclear magnetic resonance spectroscopy. Differential scanning calorimetry (DSC) revealed that the thermal polymerization temperature of the uncured CH-BZ (198 °C) was significantly lower than that of the monomer 3-phenyl-3,4-dihydro-2H-benzoxazine (263 °C). We used DSC and FTIR spectroscopy to study the curing behavior of these monomers. The degradation temperature of poly(CH-BZ) (326 °C) was higher than that poly(CP-BZ) (249 °C), based on thermogravimetric analysis. We used solution dispersion and thermal ring-opening polymerization to prepare a new class of bisbenzylidene-based polybenzoxazine (PBZ; CP-BZ or CH-BZ) composites with epoxidized soybean oil (E-SBO; 10 or 20 wt%) and E-SBO/bentonite (nanoclay; 3 or 5 wt%) for use as corrosion-protection coatings for mild steel (MS). We employed salt-spray and electrochemical measurements to investigate the influence of the epoxy and nanoclay contents, respectively, on the corrosion-resistance of these coatings. A 20 wt% epoxy content in the PBZ/E-SBO coatings provided corrosion-resistance superior to those of pure PBZs. Furthermore, the addition of 20 wt% E-SBO and 3 wt% of nanoclay decreased the corrosion rate by one order of magnitude (2.653 × 10−3 mm year–1) when compared with that of pure poly(CH-BZ) (1.292 × 10-2 mm year–1) and two orders of magnitude when compared with blank(MS) (1.094 × 10-1 mm year–1) with protection efficiency (98.16 %), revealing markedly increased barrier properties of the composite coatings towards corrosive species. Thus, these materials function as excellent corrosion-resistance coatings for MS.
TL;DR: Guar gum hydrogels are reported, cross-linked with borax and loaded with silver nanoparticles, that are injectable, exhibit rapid self-healing, and show antibacterial properties towards both gram-positive and gram-negative bacteria.
Abstract: Biomaterial-based hydrogels incorporating antibacterial agents may provide sustainable solutions to biomedical device failures and the prevention of infections. Herein we report guar gum hydrogels, cross-linked with borax and loaded with silver nanoparticles, that are injectable, exhibit rapid self-healing, and show antibacterial properties towards both gram-positive and gram-negative bacteria. The hydrogels are fully characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and rheological measurements. An important focus was to minimize borax content, thus reducing the toxicity of the gels greatly, whilst retaining their favorable viscoelastic properties. When the low borax-content hydrogels are composited with curcumin-stabilized silver nanoparticles, the hydrogels show activity against Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), and Staphylococcus aureus (S. aureus).
TL;DR: In this article, a chitosan thin film was doped with different concentrations of green synthesized silver nanoparticles (AgNPs) (100−400 μg) to improve its mechanical and antimicrobial activity.
Abstract: Chitosan is a natural polysaccharide with unique physical, chemical and biological properties that potentiates its use in many biomedical applications. In this study, chitosan thin film was doped with different concentrations of green synthesized silver nanoparticles (AgNPs) (100−400 μg) to improve its mechanical and antimicrobial activity. Transmission electron microscopy (TEM), UV–vis absorption spectroscopy and dynamic light scattering (DLS) were used to characterize the silver nanoparticles. The silver-doped chitosan films were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) in addition to assessment of their mechanical and antimicrobial properties. The characterization results revealed the successful formation of spherical silver nanoparticles with a size distribution of 100 nm ± 40 nm. The mechanical properties of chitosan film doped with silver nanoparticles (300, 400 μg) showed superior mechanical properties over pure chitosan film. Compared with pure chitosan film, silver nanoparticles doped chitosan films showed significant antibacterial activity against Staphylococcus aureus. Chitosan film doped with 300 μg AgNPs showed significant antifungal activity against Candida albicans compared with pure chitosan. Accordingly, doping of chitosan film with silver nanoparticles greatly improves its mechanical properties and antimicrobial activity.
TL;DR: In this article, the authors highlight the recent developments and challenges associated with catalytic pyrolysis technology for converting municipal mixed plastic waste (MMPW) to valuable hydrocarbon fuels.
Abstract: Present study aims to highlight the recent developments and challenges associated with catalytic pyrolysis technology for converting municipal mixed plastic waste (MMPW) to valuable hydrocarbon fuels. The study identifies gaps between conventional-thermal and catalytic pyrolysis technologies. Catalyst plays major role in pyrolysis reactions that would reflect yield of liquid product. Scale-up of pyrolysis process with MMPW is viable if catalyst used in the current existing pyrolysis process. A wide scientific literature indicates that catalyst used in pyrolysis has seen changing faces from commercial catalyst to designing of catalyst to synthesis of cheaper catalyst. However, tailored catalyst found to be very effective in processing the waste to fuels. In addition, discussion extended on the yields of liquid hydrocarbon fuel variation with the use of different catalysts in thermal pyrolysis.
TL;DR: In this paper, the authors used Hyalomma tick extract as a new green inhibitor to decrease the corrosion rate of carbon steel in 1'M HCl solution, and obtained an inhibition efficiency of 95.0 %-87.3 % with 3'g/L inhibitor in the temperature range of 25−40'°C.
Abstract: In this paper, Hyalomma tick extract as a new green inhibitor was used to decrease the corrosion rate of carbon steel in 1 M HCl solution. The polarization and electrochemical impedance spectroscopy (EIS) methods were conducted to study the corrosion properties of specimens. In addition, the field emission scanning electron microscopy (FESEM) and the atomic force microscopy (AFM) methods were utilized to investigate the morphology of corroded surfaces. When the inhibitor concentration increased from 1 to 3 g/L, the inhibition efficiency increased from 84 to 95 %, due to the polarization test results. Moreover, the inhibition efficiency of 95.0 %-87.3 % was obtained utilizing 3 g/L of inhibitor in the temperature range of 25−40 °C. Polarization test results demonstrated that Hyalomma tick extract adsorption on the steel substrate acted as a mixed inhibitor. The calculated activation energy for corrosion reactions increased from 82.26–93.38 kJ/mole K and this result demonstrated that the Hyalomma tick extract was an effective inhibitor. The adsorption of Hyalomma tick extract on the carbon steel surface would follow by the Langmuir adsorption model due to both electrochemical test results. FESEM images from the corroded surfaces represented that a much smoother surface with a few micro-pits observed in the presence of 3 g/L Hyalomma tick extract as the green inhibitor.
TL;DR: In this paper, the formation of self-organized titanium oxide nanotube layers by anodic oxidation on titanium alloys in electrolyte solutions with different temperatures (5, 10, 25, 30, 50 and 70 °C).
Abstract: We have investigated the formation of self-organized titanium oxide nanotube layers by anodic oxidation on titanium alloys in electrolyte solutions with different temperatures (5, 10, 25, 30, 50 and 70 °C). Pore diameter and the wall thickness of nanotube arrays were controlled by varying anodization time and temperature. We have observed significant outcomes in the formation of TiO2 nanotube arrays at 25 °C with an average inner pore diameter of 125 nm, length of ∼250 nm, the wall thickness of 30 nm and an inter-tube space 35 nm. Nanotube arrays were smooth and circular without any defect in morphology. In addition, anodization of Commercially Pure Titanium (CP Ti) and titanium alloys (Ti-6Al-4 V, Ti-6Al-7Nb, Ti-13Nb-13Zr, and β-21 s) was carried out at optimized parameter to understand their significance on TiO2 nanotube arrays formation.
TL;DR: In this paper, a comprehensive overview of solution blow spinning, including the principles, materials, methods, and applications, is presented, along with perspectives, challenges, opportunities, and new directions of the SBS technology.
Abstract: Solution blow spinning (SBS) is a maturing nanofiber fabrication technology. Over the past decade, there has been a growing interest in employing and developing this facile method of fabricating nanofibers, sourced from different materials to suit varied applications. For the first time, this review will provide a comprehensive overview of solution blow spinning, including the principles, materials, methods, and applications. We start with the principles of the SBS method, followed by a detailed account of the different precursor polymers (i.e., synthetic, biocompatible, and bio-based materials) and composites that have been used in the SBS of nanofibers. The proceeding section presents the known applications of nanofibers obtained through SBS which are discussed primarily in the areas of energy and electronics, biomedical, environmental, membrane separation, and, textile and smart material applications. We highlight the most important and recent advances related to SBS over the last ten years. Lastly, we give perspectives, challenges, opportunities, and new directions of the SBS technology.