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The Indian subcontinent has an abundant source of freshwater which flows in the form of rivers, streams, and khuds. These fresh sources of water are not only used to meet the requirements of water flowing through the villages, but have been harnessed for centuries by the people living in the mountainous region as a source to meet the demands of the people in a sustainable way. One of the ancient technological innovation was the establishment of Gharats, which served the people of the mountainous region for centuries by grinding the flour. This article studies the need and importance of Gharats and the challenges these Gharats face due to the industrialization. The paper is in sync with the Sustainable Development Goal 7: Affordable and Clean Energy and proposes to conserve these ancient technological masterpieces from being extinct and suggests the upgrade of these Gharats for the conservation of these heritage sites.

Biomedical implants are extensively gaining popularity owing to ever increasing health complications and growth in trauma numbers globally. Metallic implants are the most widely used bio-implants for various orthopedics and dentistry related problems owing to their superior mechanical strength when compared to ceramics and polymers. Furthermore, titanium alloys are the preferred choice these days, because of their proximate nature to human bone and light weight. However, few shortcomings make these artificial bio-implants capricious like short life span, wear rate, surface finish, etc. Tribological behavior and performance affect the life of the implant, and has to be improved for longer sustainability of the implants. Wear tests can help in predicting the life of the movable sliding joints in bio-implants. This paper includes a review about the properties of the bio material, wear tests results, and their wear mechanisms. Further, the limitation and scope of biomaterial implants from tribological aspects of various bio-materials are reviewed.

The advancements in the field of additive manufacturing have led to the significant developments in the field of biomedical sciences. This combinational progression has led to implementation of 3D printed biological components, such as cartilage, bone parts, skin layers, and other implants. Moreover, the inception of this technology in tissue engineering through integration of living cells for specific functions is another achievement bringing about a revolution in biomedical sciences. This research article aims at providing an in-depth review of the development in the additive manufacturing technologies that have been utilized for bioprinting of various tissue types, including dermal layers, bone implants, cardio-vascular parts, etc. The authors will also discuss the challenges and limitations in the technology considering the biocompatibility, mechanical properties, and incorporation of functional materials to make these artificially 3D printed components mimic properties to human biology.

In this present study the results for the tribo-testing of AISI 4140 steel specimens under fly ash nanoparticles based lubricating oils were interpreted. The results and graphical representation of coefficient of friction (COF) response for all the trails conducted under different sliding distance, sliding speed, load and concentration percentage of fly ash nanoparticles are presented this paper. The variation of COF with respect to sliding distance (SD) in each case was studied and discussed. Interpretation of the wear mechanism for the alloy steel with nano fly ash based lubricant was performed, using spectroscopy of the worn out sample pins of the AISI 4140 steel. The spectrum showed the formation of tribofilm due to the presence of oxygen in abundance, confirmed by the Scanning Electron Microscopy (SEM) and Electron Dispersive Spectroscopy (EDS) at all spectrums. Formation of tribofilm is the cause of the reduction in the wear in fly ash nanoparticles based lubricants. EDS results at the worn tip of the AISI 4140 sample has been discussed.

Metal-based functionally graded coatings have proven effectiveness in improving anti-wear properties and surface integrity of the substrates. The use of electrodeposition coating technique, considering the economics and versatility associated with this method, is a preferred technique of depositing metal-based composite coatings. Further, Ni-based composite coatings are proven for anti-wear applications, and addition of various reinforcement for developing functional coatings need to be evaluated for different applications. This study describes the development, analysis, and performance evaluation of Ni–TiN–AlN and Ni–SiC–Cr electrodeposited composite coatings on tungsten carbide (WC) tool substrates, to impart improved anti-wear properties during machining. The composite coatings were deposited and optimized for current density values of the electrodeposition process, which was identified as the most significant parameter in both the cases. The coatings were characterized using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) for microstructural analysis. The results were further analyzed for tribological behavior through microhardness and adhesion strength tests of the deposited coatings, which are significant properties imitating anti-wear characteristics of the substrate. A significant increase of 47% and 36% in microhardness was obtained for Ni–SiC–Cr coated specimen and Ni–TiN–AlN coated specimen, respectively, compared to the uncoated WC substrates, accompanied with a good adhesion strength in both the cases. The microstructural analysis in both the cases revealed an increase in the deposited coating constituents with increasing current density, leading to a denser coating deposition up to the saturation point, and then beginning of coating delamination due to over-saturation with further increase in current density.

The demand for near dry machining increases due to the adverse effect of cutting fluid on health and the environment. MQL technique offers itself as a suitable alternative for cooling and lubrication at the cutting zone during machining. In MQL mixture of a very low quantity of lubricant and compressed air is sprayed at the cutting area. Economic factor also makes it desirable as it reduces the cutting fluid cost. In this paper, the effect of MQL parameters on surface roughness and temperature during face milling of AISI 52,100 alloy steel is studied. The MQL nozzle parameters, the nozzle elevation angle, and the spray distance were selected as a process variable. A full factorial design was used to conduct the experimentations on a vertical machining center; the analysis was done by using the Analysis of variance (ANOVA) approach. A higher value of grey relational grade gives the best combination of MQL parameters for both output responses (surface roughness and temperature). The result shows that the nozzle elevation angle at 450 and a spray distance of 40 mm was the optimum process variable for both the excellent surface finish of the work piece and low temperature at the cutting zone.

Temperature has immense effect on the surface conditions of the specimen in machining process. The traditional method for lowering the temperature used in industries is flood cooling which leads to lots of environmental and health concerns. In the present work, the effect of minimum quantity lubrication has been analyzed for the outputs like cutting temperature and surface roughness in machining of EN31 alloy steel. The technique used for this multi-response optimization is Taguchi based grey relational analysis. This technique is used to conclude the best possible levels of process variables (cutting depth, feed, cutting speed and lubricant flow rate). After validation of results, the optimal conditions for process parameters achieved are speed at 700 rpm, feed at 140 mm/min, depth of cut as 0.3 mm and lubricant flow rate as 150 ml/hr. Lubricant flow rate proves its significance for the aforementioned parameters.

Ti6Al4V alloy of titanium is a significant biomaterial due to its biocompatible nature, but it lacks required bioactivity to make it mimic properties to a human bone. Thus, hydroxyl-apatite (HAp), an inorganic compound found in human bones, is generally coated onto Ti6Al4V substrates to improve their bio-characteristics. But, HAp itself lacks certain bio-functionalities, such as allowing tissue bone regeneration and poor binding to the Ti6Al4V substrate, which results in osteoporosis and reduced bioactivity of the bio-implant, respectively. The proposed way out for this is the further doping of HAp with Strontium (Sr) for enabling tissue bone regeneration as well as addition of Polydopamine (PDA) for improved adhesion of HAp-based coatings with the substrate. Moreover, PDA results in increased drug delivery area and thus can be used as a material for enhancing resistance to bacterial growth. The present study demonstrates an experimental work on deposition of HAp, HAp with PDA and HAp with PDA and Sr coatings deposited onto Ti6Al4V alloy by means of biomimetic coating technique. Initially the pure HAp coatings were deposited using 10 SBF (simulated body fluid) solution and optimized in terms of time duration for desired coating uniformity. Then, for the optimized coating duration, the PDA pretreated Ti6Al4V substrates were coated, utilizing HAp, and Sr (at two different compositions) combinations were deposited through modified 10 SBF solutions. The characterization involving microstructural analysis and phase detection was performed for all these coatings using Scanned Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD) of the coated substrates and adhesion strength was calculated using a standard pull out adhesion test ISO 13779–4. The study showed an effective and comparatively cheap method of depositing organic coatings using biomimetic technique to obtain improved bio-functionalities in metallic implants at low temperatures.

Cryogenic treatment process is seen as a supplement to heat treatment process, as it is able to instate comparative performance characteristics to workparts, as seen in the case of heat treatment p...

Electrodeposition technique for developing functionally graded composite coatings is an economical and versatile method, used for depositing metal-based coatings. This paper presents a comparison of microstructural and mechanical properties of Ni–TiC, Ni–TiN, and Ni–TiC–TiN composite coatings deposited through electrodeposition technique on tungsten carbide cutting inserts. The variable coatings deposited at optimized current and pH value were analyzed and compared in terms of microhardness and adhesion of electrodeposited specimens. The microstructure analysis of the deposited coatings was carried out using scanning electron microscope, energy dispersive spectroscopy, and X-ray diffraction, while the adhesion strength was analyzed using scratch test. All the three composite coatings showed improved mechanical characteristics and stable microstructure over uncoated tungsten carbide inserts, with Ni–TiC–TiN coating showing maximum microhardness, and Ni–TiN coating showing maximum adhesion among the three types.

Metallic materials serve a great deal in biomedical applications due to specific desired properties mimicking to human anatomy in terms of hard tissues. Of these materials titanium-based alloys are the most preferred materials in orthopaedics and dentistry due to resemblance in mechanical behaviour of these materials to human bones and dentistry. But, these materials lack in certain characteristic properties, which makes them unable to be bioactive in nature. For this, metallic biomaterials are treated to inculcate various functional properties in them. Most common of these techniques is by surface coating using bioactive materials like hydroxyapatite (HAp). Alone HAp as well as HAp-based composite coatings find significant application in improving biomedical properties of metallic materials. This paper provides an in-depth review of various developments in applications of various conventional as well as newer metallic biomaterials and discusses techniques to improve properties of these biomaterials for number of biomedical applications.

Increase in the efficiency of a gas turbine system is possible by operating it at increased temperature of hot working gases. However, it puts a direct thermal load on the material of the blade, which in turn demands for increased cooling capacities for the blade. Present paper deals with simulation based investigations on the effects of a ceramic coating of lanthanum strontium zirconate layer onto the surface temperature profile of a TMW4 gas turbine blade through an in-between bond coat layer of NiCoCrAlY. The blade model was simulated in ANSYS Workbench v14.5 for an ultra-high temperature of 1700 °C as operating temperature and calculated convection conditions from the gases and coolant air side. Steady state thermal results show a significant effect of coating in lowering substrate temperatures of blade. The results were evaluated for models with variable thickness of coating, maintaining overall dimensions of the blade constant. A blade model of 150/200 (150 microns thick bond coat and 200 microns thick top coat) experienced 8.4% reduction in maximum temperature of the substrate, while this value increased to 26.5% for a 350/1000 model.

Titanium alloy, Ti6Al4V, is an exceptional material with several desirable properties, namely, high specific strength, high corrosion and heat resistance, which make it a promising contender in number of demanding applications. However, it has poor machinability, resulting from low thermal conductivity, high chemical reactivity with tool and spring effect during cutting. These properties lead to reduced tool life during machining, due to which its usage is limited despite excellent mechanical properties. Therefore, optimization of process parameters using response surface methodology in face milling of Ti6Al4V alloy with uncoated carbide tools has been investigated experimentally in this work. This article is focused on developing mathematical relation between input factors and response parameters, namely, surface roughness (Ra), tool wear (Tw) and tool vibration (Tv). The machining parameters are optimized for minimum Ra, Tw and Tv values. The optimal parameters are validated experimentally which showed a good agreement with the predicted results. The feed rate was found to be the most influential parameter affecting Ra and Tv, whereas cutting speed is the most effective in influencing Tw.

Ti6Al4V is the most widely used titanium alloy and is a demanding material in applications requiring high specific strength and corrosion resistance, that is, aerospace, automobile and biomedical industries. However, the poor machinability of this alloy, resulting from its low thermal conductivity, high hardness at elevated temperatures, high chemical reactivity with the cutting tool and low elastic modulus, restricts its usage. As a result, the tool life in machining of Ti6Al4V is substantially less than conventional materials such as steel and aluminium. This work reviews the various techniques employed in improving the machinability of Ti6Al4V alloy, from the perspective of cutting tool technology. The focus is onto the parameters affecting tool life in machining of Ti6Al4V alloy with some trending techniques and their feasibility, considering the economics to develop the best techno-economic method.

The paper discusses the potential ingress and combined effect of moisture and temperature on pre-fatigued glass fibre-reinforced polymers standard test specimens. An experimental investigation was conducted to analyse the behaviour of glass fibre-reinforced polymers’ in environmental conditions similar to that of tropical environments. The standard pre-fatigued glass fibre-reinforced polymers specimens were subjected to varying hygrothermal conditions: three different temperatures, i.e. natural bath, 45 ℃ and 55 ℃ to study the degradation in strength and related properties. Several macro-structural and micro-structural tests were conducted to determine the damage. The effect of these conditions on characteristics such as diffusivity, weight gain, resin volume fraction, conductivity and deterioration of ultimate tensile strength was determined. The maximum reduction in strength is found to be approximately 39% for the specimen exposed to 55 ℃ water bath for 60 days. This study shall be helpful in estimating the characteristics of glass fibre-reinforced polymers composites subjected to cyclic fatigue loads in the tropical conditions.

Advances in soft computing reshape the manufacturing industries to develop an integrated, self-adjusting manufacturing systems into dynamically scalable and highly distributed cost-efficient business model. Due to presence of uncertainty and inaccuracy in manufacturing processes, the various soft computing algorithms i.e. neural networks, fuzzy sets, genetic algorithms, ant colony optimization, adaptive neural fuzzy inference system, swarm optimization technique and simulated annealing have been applied for anticipating the performance of the metal cutting processes and optimizing them. The paper presents the state-of-the-art review on the soft computing techniques applied for the prediction of multi-response parameters in material removal processes.

Machines without vibrations during operation are something non-existent which results in deterioration of machine tools. The condition based monitoring has become a crucial technique to ensure the machine availability by timely maintenance actions and reducing breakdown maintenance. Several condition monitoring techniques have been reported viz. vibration monitoring, acoustic emission monitoring, chemical monitoring, thermal monitoring and therefore new methods to improve the reliability, effectiveness, accuracy of the fault detection need to be evaluated. Vibration analysis is proven to be an important criterion for fault diagnosis in manufacturing processes and maintenance scheduling for various manufacturing equipment. This paper presents an overview of recent trends in condition monitoring and signal processing methods used for predictive maintenance of dynamic systems.