Effects of Minimum Quantity Lubrication (MQL) in machining processes using conventional and nanofluid based cutting fluids: A comprehensive review

Tissue engineering (TE) and regenerative medicine integrate information and technology from various fields to restore/replace tissues and damaged organs for medical treatments. To achieve this, scaffolds act as delivery vectors or as cellular systems for drugs and cells; thereby, cellular material is able to colonize host cells sufficiently to meet up the requirements of regeneration and repair. This process is multi-stage and requires the development of various components to create the desired neo-tissue or organ. In several current TE strategies, biomaterials are essential components. While several polymers are established for their use as biomaterials, careful consideration of the cellular environment and interactions needed is required in selecting a polymer for a given application. Depending on this, scaffold materials can be of natural or synthetic origin, degradable or nondegradable. In this review, an overview of various natural and synthetic polymers and their possible composite scaffolds with their physicochemical properties including biocompatibility, biodegradability, morphology, mechanical strength, pore size, and porosity are discussed. The scaffolds fabrication techniques and a few commercially available biopolymers are also tabulated.

A Comparative Review of Natural and Synthetic Biopolymer Composite Scaffolds.

Bone tissue engineering (BTE) is a rapidly growing field aiming to create a biofunctional tissue that can integrate and degrade in vivo to treat diseased or damaged tissue. It has become evident that scaffold fabrication techniques are very important in dictating the final structural, mechanical properties, and biological response of the implanted biomaterials. A comprehensive review of the current accomplishments on scaffold fabrication techniques, their structure, and function properties for BTE is provided herein. Different types of biomaterials ranging from inorganic biomaterials to natural and synthetic polymers and related composites for scaffold processing are presented. Emergent scaffolding techniques such as electrospinning, freeze-drying, bioprinting, and decellularization are also discussed. Strategies to improve vascularization potential and immunomodulation, which is considered a grand challenge in BTE scaffolding, are also presented.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adfm.202010609

Scaffold fabrication technologies and structure/function properties in bone tissue engineering

A colloidal mixture of nanometre-sized (<100 nm) metallic and non-metallic particles in conventional fluid is called nanofluid. Nanofluids are considered to be potential heat transfer fluids because of their superior thermal and tribological properties. In recent period, nanofluids have been the focus of attention of the researchers. This paper presents a summary of a number of important research works that have been published on rheological behaviour of nanofluids. This review article not only discusses the influence of particle shape and shear rate range on rheological behaviour of nanofluids but also studies other factors affecting the rheological behaviour. These other factors include nanoparticle type, volumetric concentration in different base fluids, addition of surfactant and externally applied magnetic field. From the literature review, it has been found that particle shape, its concentration, shear rate range, surfactant and magnetic field significantly affect the rheological behaviour of any nanofluid. It has been observed that nanofluids containing spherical nanoparticles are more likely to exhibit Newtonian behaviour and those containing nanotubes show non-Newtonian flow behaviour. Furthermore, nanofluids show Newtonian behaviour at low shear rate values while behave as non-Newtonian fluid at high shear rate values. Authors have also identified the inadequacies in the research works so far which require further investigations.

Rheological behaviour of nanofluids: A review

Natural bone is a mineralized biological material, which serves a supportive and protective framework for the body, stores minerals for metabolism, and produces blood cells nourishing the body. Normally, bone has an innate capacity to heal from damage. However, massive bone defects due to traumatic injury, tumor resection, or congenital diseases pose a great challenge to reconstructive surgery. Scaffold-based tissue engineering (TE) is a promising strategy for bone regenerative medicine, because biomaterial scaffolds show advanced mechanical properties and a good degradation profile, as well as the feasibility of controlled release of growth and differentiation factors or immobilizing them on the material surface. Additionally, the defined structure of biomaterial scaffolds, as a kind of mechanical cue, can influence cell behaviors, modulate local microenvironment and control key features at the molecular and cellular levels. Recently, nano/micro-assisted regenerative medicine becomes a promising application of TE for the reconstruction of bone defects. For this reason, it is necessary for us to have in-depth knowledge of the development of novel nano/micro-based biomaterial scaffolds. Thus, we herein review the hierarchical structure of bone, and the potential application of nano/micro technologies to guide the design of novel biomaterial structures for bone repair and regeneration.

Effect of the nano/microscale structure of biomaterial scaffolds on bone regeneration

Development and Performance Evaluation of Galactomannan Polymer-Based Abrasive Medium to Finish Atomic Diffusion Additively Manufactured Pure Copper Using Abrasive Flow Finishing

In the field of dry machining, recent researchindicates that surface texture has potential to influence tribological conditions. However, very little attention has been given to controlled surface texturing of cutting tools. An experimental study of the performance of the micro-texture high speed steel (HSS) grade M2 cutting tool in machining of AISI 1040 steel samples is carried out. Surface textures were made using Rockwell hardness tester on rake face of the HSS M2 tool. Structural analyses are done on cutting tool using ANSYS workbench to evaluate the effect of micro-texture on the stresses and strains generationat cutting edge of the cutting tool in cutting operations. It is found that the effect of micro-texture on stress generation is very small which can be neglected. Dry cutting tests were carried out on AISI 1040 steel sample using lathe machine with micro-textured tools and conventional cutting tool for a varying range of feed and cutting speed. The machining performance was analyzed in terms of feed force, cutting force and coefficient of friction. The results demonstrate that the surface texture on the rake face of cutting tools significantly reduces cutting forces and coefficient of friction when compared with that of the conventional tool.

/pdf/experimental-comparative-study-of-conventional-andmicro-1x5tx7mhrq.pdf

Experimental Comparative Study of Conventional andMicro- Textured Tools during Machining of AISI 1040 Alloy Steel

Bio-micromachining is upcoming future unconventional manufacturing process. It has many benefits over other conventional as well as non-conventional process, some of them are no heat-affected zone, no recast layer, no formation of the white layer, and many others. In the present paper, bio-micromachining on copper has been demonstrated. Fabrication of microchannel, as well as optimisation of the process, is done by using central composite run design (CCRD) in combination with response surface methodology (RSM). ANOVA analysis shows that the machining time is the main influencing parameter followed by inoculum size. The maximum material removal obtained was 0.571 grams, when machining time was 32 h and inoculum size was 7.5% (v/v). It is suggested to use the inoculum age of microorganism after 5 days of culture and best before 12 days, in order to get the maximum amount of material removal.

Empirical Modelling and Optimisation of Bio-Micromachining on Antimicrobial Copper to Fabricate Micromixing System

Additive manufacturing is a trending technology and has many applications in the automotive industry, aerospace industries, competitive sport, jewelry, and medicine. The customized complex parts produced using 3D printing have generally rough surfaces; the surface may contain partially sintered particles. Therefore, the surface quality needs to be enhanced; surface roughness should be decreased for further applications, and dimensional accuracy is to be achieved. The 3D printed parts have inaccessible areas like internal surfaces, narrow channels, and cavities which are difficult to finish with conventional tools. Hence, to get desired surface finish, a post-processing technique is used; chemical polishing is one of them. Chemical polishing is an economical and acceptable finishing process in today’s growing technology. And using the chemical polishing, post-processing technique improves not only surface quality but also mechanical efficiency. In this study, chemical polishing of 3D printed Inconel 718 using three different compositions H2SO4 + methanol, ethanol + HCl + FeCl3, and HF + HCl + HNO3 is studied and tried to optimize the chemical composition to achieve a better surface finish. 

M. Ravi Sankar

Papers

Development and Performance Evaluation of Galactomannan Polymer-Based Abrasive Medium to Finish Atomic Diffusion Additively Manufactured Pure Copper Using Abrasive Flow Finishing

Experimental Comparative Study of Conventional andMicro- Textured Tools during Machining of AISI 1040 Alloy Steel

Empirical Modelling and Optimisation of Bio-Micromachining on Antimicrobial Copper to Fabricate Micromixing System

Experimental Study on Chemical Polishing of Laser Powder Bed Fusion-Based Inconel 718 Features

Engineered approach coupled with machine learning in biofabrication of patient-specific nerve guide conduits - Review