An experimental study of PMMA precision cryogenic micro-milling

Polymethyl methacrylate (PMMA) has been used more and more widely in the fields of microfluidic devices and high-precision optical components due to its excellent mechanical and optical properties. Micro-milling is one of the methods that has been used in the machining of polymer materials. The machinability of PMMA is highly dependent on temperature, and the cryogenic method is also applied to control the processing temperature. In this work, the PMMA was milled with different processing parameters at the temperature of -55℃ and 25℃. The influence of each milling parameter on the surface quality under different temperature conditions were investigated. According to the results, the cutting depth is the dominant factor that influenced the surface roughness. The shape accuracy of the rectangular microgroove processed under low-temperature conditions is better. The material removal mechanism under different temperatures was also discussed, and the material is cut in a brittle way under low temperatures.

Potential of magnetic nano cellulose in biomedical applications: Recent Advances

Biopolymers have attracted considerable attention in various biomedical applications. Among them, cellulose as sustainable and renewable biomass has shown potential efficacy. With the advancement in nanotechnology, a wide range of nanostructured materials have surfaced with the potential to offer substantial biomedical applications. . The progress of cellulose at the nanoscale regime (nanocelluloses) with diverse forms like cellulose nanocrystals, nanofibres and bacterial nanocellulose) has imparted remarkable properties like high aspect-ratio and high mechanical strength, and biocompatibility. The amalgamation of nanocellulose together with magnetic nanoparticles (MNC) could be explored for a synergistic effect. In this review, a brief introduction of nano cellulose , magnetic nanoparticles and the synergistic effect of MNC is described. Further, the review sheds light on the recent studies based on MNCs with their potential in the biomedical area. Finally, the review is concluded by citing the remarkable value of MNC with their futuristic applications in other fields like friction layers for triboelectric nanogenerator (TENG), energy production, hydrogen splitting, and wearable electronics.

Carbon-based nanomaterials with multipurpose attributes for water treatment: Greening the 21st-century nanostructure materials deployment

Nanotechnology is a top priority research area in a plethora of technological and scientific fields due to its economic impact and versatile capability. Among various applications, water treatment is considered among the most prospective utilization of nanotechnology, where a large number of nanostructured materials can remediate water using several different mechanistic ways. For achieving this, nanomaterials can be combined and modified with active moieties to develop different nanocomposites with structural diversity and unique physicochemical attributes. In addition, they have also been designed and integrated into membranes for improving water treatment performance. In this review, we provide an up-to-date overview of various nanostructured materials as nanoadsorbents, such as carbon-based nanomaterials, nanocomposites, and nanomembranes for remediating pesticide-based pollutants from aqueous systems using CNTs. Notably, nanomaterials are capable of efficiently removing environmental pollutants given their substantial surface area, high absorptive ability, and excellent environmental selectivity and compatibility.

Computational prediction of electrical and thermal properties of graphene and BaTiO3 reinforced epoxy nanocomposites

Graphene based materials e.g., graphene oxide (GO), reduced graphene oxide (RGO) and graphene nano platelets (GNP) as well as Barium titanate (BaTiO3) are emerging reinforcing agents which upon mixing with epoxy provides composite materials with superior mechanical, electrical and thermal properties as well as shielding against electromagnetic (EM) radiations. Inclusion of the aforementioned reinforcing agents has shown to improve the performance, however, the extent of improvement has remained uncertain. In this study, a computational modelling approach was adopted using COMSOL Multiphysics software in conjunction with Bayesian statistical analysis to investigate the effects of including various filler materials e.g. GO, RGO, GNP and BaTiO3 in influencing the direct current (DC) conductivity (σ), dielectric constant (ε) and thermal properties on the resulting epoxy polymer matrix composites. The simulation of epoxy composites were performed for different volume percentage of the filler materials by varying the geometry of the filler material. It was observed that the content of GO, RGO, GNPs and the thickness of graphene nanoplatelets can alter the DC conductivity, dielectric constant, and thermal properties of the epoxy matrix. The lower thickness of GNPs was found to offer the larger value of DC conductivity, thermal conductivity and thermal diffusivity than rest of the graphene nanocomposites, while, the RGO showed better dielectric constant value than neat epoxy, and GO, GNP nanocomposites. Similarly, BaTiO3 nanoparticles content and diameter were observed to alter the dielectric constant, DC conductivity and thermal properties of modified epoxy in several order magnitude than neat epoxy. In this way, the higher diameter particles of BaTiO3 showed better DC conductivity properties, dielectric constant value, thermal conductivity and thermal diffusivity. Moreover, this research provides guidance for further computational examination on the selection of GNP and BaTiO3 materials for the enhancement of the electrical and thermal properties of the epoxy matrix.

Synthesis of Biogenic silver nanoparticles using plant growth-promoting bacteria: Potential use as biocontrol agent against phytopathogens

Biogenic nanoparticles (NPs) derived from microbes present an excellent opportunity to deal with various challenges in medicine, diagnosis, environment and agriculture. In the area of agriculture sciences, researchers are facing challenges related to excessive utilization of pesticides which can be answered by utilizing plant growth-promoting (PGP) microbes. Herein, we have employed the culture filtrate of two PBP bacteria strains, Serratia marcescens and Burkholderia cepacia to prepare biogenic silver NPs. The biogenic silver NPs were characterized by various techniques viz. UV-VIS spectroscopy, SEM, XRD and FTIR. The biogenic AgNPs were able to control the growth of phytopathogenic fungi Aspergillus niger, A. fumigatus, Fusarium oxysporum, Pythium sp., and Rosellinia sp. by more than 80% as examined by in vitro growth reduction on agar medium. Very significantly, the growth inhibition of seedlings by phytopathogenic fungi was efficiently rescued using biogenic AgNPs derived from PGP bacteria. These results indicate the potential use of biogenic NPs to reduce the burden of chemical-based pesticides.