High performance thermoplastic composite from flat knitted multi-layer textile preform using hybrid yarn

Modern flat knitting machines using high performance yarns are able to knit fabrics including the reinforcement yarns arranged differently into knit structures. Due to their improved mechanical properties, composites made from multi-layer knit fabrics show great potential in lightweight applications. This paper reports on the development of flat knitted multi-layer textile preforms for high performance thermoplastic composites using hybrid yarns made of glass (GF) and polypropylene (PP) filaments. Such textile preforms with different reinforcements were used to consolidate into 2D thermoplastic composites. Moreover, the mechanical properties of these composites were studied. The mechanical properties of 2D composites were found to be greatly affected by different arrangements of reinforcement yarns. The integration of reinforcement yarns as biaxial inlays (warp and weft yarns) is found to be the best solution for knitting, whereas tuck stitch shaped and unidirectional arranged reinforcements offer also promising application possibilities.     

Structure, magnetic and thermal properties of Gd2MnTiO6

A new perovskite compound Gd₂MnTiO₆ was synthesized and its crystal structure, magnetic and thermal properties have been investigated. The XRD patterns were refined by the Rietveld method and the refined lattice parameters with the monoclinic space group P2₁/n (No. 14) were a=0.5398 (2), b=0.5704 (2), c=0.7767 (2) nm and β=89.68 (2)°. The antiferromagnetic behavior was observed below 16.0 K and λ-type heat capacity was measured near this temperature.     

Properties enhancement using oil palm shell nanoparticles of fibers reinforced polyester hybrid composites

Oil palm shell (OPS) nanoparticles were utilized as filler in fibers reinforced polyester hybrid composites. The OPS nanoparticles were successfully produced from the raw OPS using high-energy ball milling process. Fundamental properties including morphology, crystalline size, and particle size of the OPS nanoparticles were determined. Tri-layer natural fiber reinforcement (kenaf–coconut–kenaf fiber mat) polyester hybrid composites were prepared by hand lay-up techniques. The influences of the OPS nanoparticles loading in the natural fibers reinforced polyester hybrid composites were determined by analyzing physical, mechanical, morphological, and thermal properties of the composites. Results showed that the incorporation of the OPS nanoparticles into the hybrid composites enhanced the composite properties. Further, the natural fibers reinforced polyester hybrid composite had the highest physical, mechanical, morphological, and thermal characteristics at 3 wt.% OPS nanoparticles loading.     

Does academic collaboration equally benefit impact of research across topics? The case of agricultural,resource, environmental and ecological economics

Collaboration is a major factor in the knowledge and innovation creation in emerging science-driven industries where the technology is rapidly changing and constantly evolving, such as nanotechnology. The objective of this work is to investigate the role of individual scientists and their collaborations in enhancing the knowledge flows, and consequently the scientific production. The methodology involves two main phases. First, the data on all the nanotechnology journal publications in Canada was extracted from the SCOPUS database to create the co-authorship network, and then employ statistical data mining techniques to analyze the scientists’ research performance and partnership history. Also, a questionnaire was sent directly to the researchers selected from our database seeking the predominant properties that make a scientist sufficiently attractive to be selected as a research partner. In the second phase, an agent-based model using Netlogo has been developed to study the network in its dynamic context where several factors could be controlled. It was found that scientists in centralized positions in such networks have a considerable positive impact on the knowledge flows, while loyalty and strong connections within a dense local research group negatively affect the knowledge transmission. Star scientists appear to play a substitutive role in the network and are selected when the usual collaborators, i.e., most famous, and trustable partners are scarce or missing.     

Effect of divalent cation substitution in the magnetoplumbite structured BaFe12O19 system

Synthesis of magnetically ordered barium hexaferrite powders and the adjustment of magnetic properties for perpendicular magnetic recording media are realized through substitution of divalent cation (Ca) in the BaFe₁₂O₁₉ system. The Ca²⁺ substituted Ba_1?xCa_xFe₁₂O₁₉ (where x = 0.05, 0.1, 0.15 and 0.2) compounds have been prepared through solid state reaction technique. The powder X-ray diffraction analysis reveals that all the prepared compounds crystallized in magnetoplumbite hexagonal structure and the flat hexagonal platelet morphology of the crystallites was identified through scanning electron microscopy. The formation of magnetoplumbite structured Ba_1?xCa_xFe₁₂O₁₉ system due to mechanical activation was supported by micro-Raman measurements. Both pure and Ca substituted BaFe₁₂O₁₉ compounds exhibit sharp intense peaks which reveals defect free environment in the crystal lattice. From the room temperature magnetization studies, it was observed that the saturation magnetization (M_S) and remanent magnetization (M_R) values drastically decreases for the Ba_0.95Ca_0.05Fe₁₂O₁₉ compound which may be due to the existence of spin canting effect and leads to the reduction of super exchange fields. The increase in M_S and M_R values for the Ba_0.9Ca_0.1Fe₁₂O₁₉ and Ba_0.85Ca_0.15Fe₁₂O₁₉ compounds could be attributed to the enhanced hyperfine fields at 12k and 2b sites due to the strengthening of Fe³⁺–O–Fe³⁺ super exchange interactions. A large reduction in the coercivity value from 3,090 to 1,548 Gauss may be attributed to the fall in magneto crystalline anisotropy. The high temperature magnetization studies infer that while increasing substitution level of Ca in the BaFe₁₂O₁₉ system results in decreasing trend in Curie temperature. The room temperature dielectric measurement shows that the incorporation of Ca²⁺ in the BaFe₁₂O₁₉ system results with increase in the dielectric constant and this case substantiates the space charge polarization. The magnetically ordered BaFe particulate having higher saturation and low coercivity values with superior magnetic and dielectric behaviour exhibiting the possibility for future high-recording-density storage products.     

Ultrafast Acoustofluidic Exfoliation of Stratified Crystals

While the remarkable properties of 2D crystalline materials offer tremendous opportunities for their use in optics, electronics, energy systems, biotechnology, and catalysis, their practical implementation largely depends critically on the ability to exfoliate them from a 3D stratified bulk state. This goal nevertheless remains elusive, particularly in terms of a rapid processing method that facilitates high yield and dimension control. An ultrafast multiscale exfoliation method is reported which exploits the piezoelectricity of stratified materials that are noncentrosymmetric in nature to trigger electrically‐induced mechanical failure across weak grain boundaries associated with their crystal domain planes. In particular, it is demonstrated that microfluidic nebulization using high frequency acoustic waves exposes bulk 3D piezoelectric crystals such as molybdenum disulphide (MoS₂) and tungsten disulphide (WS₂) to a combination of extraordinarily large mechanical acceleration (≈10⁸ m s^?2) and electric field (≈10⁷ V m^?1). This results in the layered bulk material being rapidly cleaved into pristine quasi‐2D‐nanosheets that predominantly comprise single layers, thus constituting a rapid and high throughput chip‐scale method that opens new possibilities for scalable production and spray coating deposition.     

Study of sintering behavior of vapor forms of 1-octanethiol coated copper nanoparticles for application to ink-jet printing technology

Sub-50 nm copper nanoparticles coated with sub-5 nm 1-octanethiol layer for oxidation inhibition were examined to confirm the 1-octanethiol removal temperature as the sub-50 nm copper nanoparticles are sintered. As a result, 1-octanethiol Self-Assembled Multi-layers (SAMs) on sub-50 nm copper nanoparticles were successfully removed before sintering of copper nanoparticles so that a high density of copper line could be obtained. Finally, the line resistivity was measured and compared to verify the effect of sintering in different atmospheres. As a result, electrical resistivity of the copper pattern sintered in hydrogen atmosphere was measured at 6.96 x 10(-6) ohm-cm whereas that of the copper pattern sintered in mixed gas atmosphere was measured at 2.62 x 10(-5) ohm-cm. Thus, sintering of copper patterns was successfully done to show low electrical resistivity values. Moreover, removal of 1-octanethiol coating after sintering process was confirmed using X-ray photoelectron spectroscopy (XPS) analysis. By showing no sulfur content, XPS results indicate that 1-octanethiol is completely removed. Therefore, the vapor form of 1-octanethiol coating layers can be safely used as an oxidation inhibition layer for low temperature sintering processes and ink-jet applications.     

Nanoneurotherapeutics approach intended for direct nose to brain delivery

Abstract

Context: Brain disorders remain the world's leading cause of disability, and account for more hospitalizations and prolonged care than almost all other diseases combined. The majority of drugs, proteins and peptides do not readily permeate into brain due to the presence of the blood–brain barrier (BBB), thus impeding treatment of these conditions.

Objective: Attention has turned to developing novel and effective delivery systems to provide good bioavailability in the brain.

Methods: Intranasal administration is a non-invasive method of drug delivery that may bypass the BBB, allowing therapeutic substances direct access to the brain. However, intranasal administration produces quite low drug concentrations in the brain due limited nasal mucosal permeability and the harsh nasal cavity environment. Pre-clinical studies using encapsulation of drugs in nanoparticulate systems improved the nose to brain targeting and bioavailability in brain. However, the toxic effects of nanoparticles on brain function are unknown.

Result and conclusion: This review highlights the understanding of several brain diseases and the important pathophysiological mechanisms involved. The review discusses the role of nanotherapeutics in treating brain disorders via nose to brain delivery, the mechanisms of drug absorption across nasal mucosa to the brain, strategies to overcome the blood brain barrier, nanoformulation strategies for enhanced brain targeting via nasal route and neurotoxicity issues of nanoparticles.     

Adaptive reduced order modeling for nonlinear dynamical systems through a new a posteriori error estimator: Application to uncertainty quantification

Multiquery problems such as uncertainty quantification (UQ), optimization of a dynamical system require solving a differential equation at multiple parameter values. Therefore, for large systems, the computational cost becomes prohibitive. This issue can be addressed by using a cheaper reduced order model (ROM) instead. However, the ROM entails error in the solution due to approximation in a lower dimensional subspace. Moreover, the ROM lacks robustness over a wide range of parameter values. To address these issues, first, an upper bound on the norm of the state transition matrix is derived. This bound, along with the residual in the governing equation, are then used to develop an error estimator for general nonlinear dynamical systems. Furthermore, this error estimator is used in conjunction with the modified greedy search algorithm proposed by Hossain and Ghosh (Int J Numer Methods Eng, 2018;116(12-13): 741-758) to adaptively construct a robust proper orthogonal decomposition-based ROM. This adaptive ROM is subsequently deployed for UQ by invoking it in a statistical simulation. Two numerical studies: (i) viscous Burgers' equation and (ii) beam on nonlinear Winkler foundation, showed an improved accuracy of the error estimator compared to the current literature. A significant computational speed-up in UQ is achieved.     

Properties of epoxidized palm oil plasticized polytlactic acid

In this study, epoxidized palm oil (EPO) was utilized as a plasticizer for polylactic acid (PLA) using chloroform as a solvent by solution casting process at six weight ratios of PLA/EPO, 95/05, 90/10, 80/20, 70/30, 60/40, and 50/50, respectively. Fourier-transform infrared (FTIR) spectroscopy was used to identify the functional groups of PLA, EPO, and PLA/EPO blends. Thermal stability, mechanical, and morphological properties of the blends were investigated by thermogravimetric analyzer (TGA), tensile properties measurements, and scanning electron microscope (SEM) technique, respectively. The FTIR spectra indicate that there are some molecular interactions by intramolecular hydrogen bond between PLA and EPO. All sets of PLA/EPO blends show high thermal stability and significant improvement of mechanical properties compare to pure PLA. The highest elongation at break (about 210%) was obtained when the ratio of PLA/EPO blend was 80/20. Morphological results of PLA/EPO blends show that ESO was good miscible with PLA.