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

Experimental Study and Modeling of Machining with Dry Compressed Air, Flood and Minimum Quantity Cutting Fluid Cooling Techniques

Biowastes Processed Hydroxyapatite filled Poly (Lactic acid) Bio-Composite for Open Reduction Internal Fixation of Small Bones

Magnetic abrasive finishing is one of the advanced finishing processes where in the iron (Fe) particles form a flexible matrix in which the abrasives are trapped when magnetic field is applied. In the present paper, the magnetic flux densities (MFD) are measured at various distances from the outer surface to centre on ferromagnetic and non–ferromagnetic materials with approximately same hardness. MFD is about three times higher on ferromagnetic compared to non–ferromagnetic workpiece. Complete experimental study is carried out and empirically modelled. Best final Ra value about 20 nm and 60 nm is achieved on ferromagnetic and non–ferromagnetic stainless steel, respectively. With increase in abrasive mesh size and decrease in working gap, percentage change in Ra (%ΔRa) increases. Online measurement of forces is done using indigenously developed ring type dynamometer. Normal magnetic force is much higher in case of ferromagnetic than non–ferromagnetic workpiece material but no significant change is found in tangential cutting force.

Experimental study and empirical modelling of magnetic abrasive finishing on ferromagnetic and non–ferromagnetic materials

Experimental Investigations and Surface Morphology of Bio-Micromachining on Copper

AISI 1040 steel is widely used material in most of industrial manufacturing applications. In order to meet the increasingly demanding stringent operating conditions, the functional surface of the concerned components which are made of AISI 1040 are modified in such a way that they can sustain in the aggressive environment. In this paper cladding of Ni/La 2O3 composite powder (particle size ~40µm) has been done through microwave irradiation. This processing has been explored for enhancement of surface properties of AISI 1040 steel. The favourable property of microwave processing is that the volumetric nature of heating of the material results in uniform thermal gradient, which yields uniform material properties in the processed materials. The developed Ni/La 2O3 composite clad surfaces on AISI 1040 steel substrate was characterized using scanning electron microscope for surface morphology. The average thickness was observed to be ~500 µm and the developed Ni/La 2O3 composite clad surface shows good metallurgical bonding with the AISI 1040 substrate material. The mechanical property such as hardness were also measured and found to be improved.

/pdf/experimental-investigations-of-ni-la-2o3-composite-micro-40o96a48zd.pdf

M. Ravi Sankar

Papers

Experimental Study and Modeling of Machining with Dry Compressed Air, Flood and Minimum Quantity Cutting Fluid Cooling Techniques

Biowastes Processed Hydroxyapatite filled Poly (Lactic acid) Bio-Composite for Open Reduction Internal Fixation of Small Bones

Experimental study and empirical modelling of magnetic abrasive finishing on ferromagnetic and non–ferromagnetic materials

Experimental Investigations and Surface Morphology of Bio-Micromachining on Copper

Experimental Investigations of Ni/La 2O3 Composite Micro-Cladding on AISI 1040 Steel through Microwave Irradiation