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Influenza like pandemics are a severe threat to any established health care system as many thousands of patients would need emergency ventilator support during the acute respiratory failure stage, and this quickly overloads the existing facilities. The present article addresses the design and development of a human breathing assist machine (ventilator) prototype for use by qualified medical professionals in the emergency room, as well as in other locations, where a regular ventilator machine cannot be made available. The ventilator has been designed using readily available locally sourced materials, which can be assembled in a short time. This ensures the minimum required features to ventilate a patient in emergency conditions. The popular crank-rocker mechanism has been used to meet some of the vital design requirements of the emergency ventilator. The size of the links has been chosen to maintain a fixed inspiratory-to-expiratory (I:E) time ratio of 1:2. The kinematic linkage design has been kept modular by introducing a feature to adjust the location of the rocker tip to control the tidal volume from 100 ml to 600 ml of oxygenated air per breath. A virtual CAD model, based on the above-mentioned linkage design, has been designed to assess the variation of the position and velocity with time. Finally, a working prototype has been made, and it was observed that the I:E time ratio of 1:2 was achieved satisfactorily.

According to the World Health Organization (WHO), approximately 5% of the world’s population has a hearing loss disability caused by various reasons. The cochlea is a spiral-shaped bone found in the inner ear that is capable of doing exceptional sound analysis, in terms of both frequency and intensity which allows the perception of sound frequency in the range of 20 Hz to 20 kHz. An artificial basilar membrane having various shapes has been developed but none of those covers the whole human audible frequency range. This paper compares the mechanical characteristics of the rectangular and taper piezoelectric cantilever to develop an artificial basilar membrane that mimics the human cochlea with high sensitivity. The cantilever beam is made up of molybdenum (Mo), aluminum nitride (AlN), tungsten (W) and the desired frequency range is obtained by varying the length and thickness of the cantilever beams. The 3D design and simulations were performed by COMSOL Multiphysics to study the Eigen frequency, displacement, and stress measurements of the cantilever. The Eigen frequency is observed to be increased with an increase in the thickness and decrease in the length for both rectangular and taper cantilever beam. The rectangular beam showed higher sensitivity and lower stresses compared to the taper beam. Therefore, the rectangular cantilever beam is more suitable to mimic the basilar membrane of the human cochlea.

The potential usage of Copper (Cu) is very limited, where combined mechanical and thermal properties are desirable, which can be overcome by using carbon nanotube (CNT) as a reinforcement. An attempt was made to synthesize Cu/CNT composites by varying CNT diameter and its concentration through a molecular level mixing technique followed by uniaxial compaction and conventional sintering. The sintering behaviour of Cu and Cu/CNT composites was studied to understand the influence of different parameters. The sintering duration of Copper was decreased with an increase of CNT diameter. The maximum enhancement of properties was achieved at 0.25 wt.% CNT irrespective of its diameter, where the thermal conductivity and hardness were obtained as 328 W/mK at 20–40 nm diameter CNT composites and 81.2 ± 2.9 VHN at 40–60 nm diameter CNT composites, respectively. The conventional method of synthesize can generate the desired characteristics of composites at par with high end techniques, such as SPS.

Among the several unresolved issues, profound/total loss of low-frequency residual hearing after cochlear implant fixation is the most frequent event. Even after several attempts such as modifications in the design of electrodes, improvement in the surgical procedures and use of protective drugs to minimize the trauma and its after-effects, residual hearing has been retained in less than 50% patients only. Surgical procedure and mechanical trauma at the electrode insertion site are thought to be responsible for excess generation of reactive oxygen species (ROS) following initiation of inflammatory cytokines resulting into loss of residual hearing due to programmed cell death of essential inner ear structures. Though very recent studies have reported the use of conventional antioxidants to preserve the residual hearing, they have their own limitations. With the emerging need of better and effective antioxidants, nanoceria has spurred immense research interest on utilizing its unique catalytic characteristics for ROS-associated diseases. Nanoceria has shown effective protection against several ROS-induced damages compared to conventional antioxidants such as vitamin C and vitamin E. The objective of the present work is to develop an understanding about the underlying mechanism of loss of residual hearing and propose a novel method based on delivery of nanoceria to minimize it. The first part of the article highlights the failure of cochlear implants, nature of failures and revised surgeries due to loss of residual hearing. Subsequently, the article explores the relation among surgical/mechanical trauma, excess generation of ROS at electrode insertion site, progressive death of hair cells and loss of residual hearing. Finally, effectiveness of radical scavenging characteristics of nanoceria along with controlling parameters and involved mechanisms has been reviewed. The present work also focuses on the limitations and challenges of nanoceria in clinical applications. Based on the literature review, it is hypothesized that the residual hearing loss is associated with excess generation of ROS and it is proposed that the delivery of effective antioxidants/radical scavengers having a good longevity and regenerative ability is expected to reduce the excess level of ROS and retain the residual hearing.

The thermophysical properties of graphene nanofluids in thermosyphon have been studied at different power inputs, temperatures and angles of inclination. The thermal conductivity of the graphene nanofluid is found to be 29% higher than that of the deionized water at 45 °C. The viscosity of the graphene nanofluid increased with the concentration of graphene nanoparticles and decreased with increasing the temperature. It is observed that the wall temperature distribution of graphene nanofluid is found to be decreased in comparison to that of deionised water. The thermal resistance of thermosyphon is reduced with increasing the power input and irrespective of the inclination angle. Keywords: Graphene platelet nanoparticle, Thermosyphon, Thermal conductivity, Viscosity, Thermal resistance

Four-dimensional (4D) printing has great potential for fabricating patient-specific, stimuli-responsive 3D structures for the medical sector. Porous Shape memory polymers have high volumetric expansion and enhanced biological activity, which make them as ideal candidates for implant materials through minimally invasive surgical procedures. The objective of the present work is to develop a radiopaque, porous, and custom shaped shape memory polyurethane (SMPU) for its application in endovascular embolization. In this paper, the porous SMPU was fabricated by combining extrusion, fused filament fabrication (FFF) and salt leaching. The filament for FFF was produced by extruding the mixture of SMPU, NaCl, and Tungsten at the desired composition. The 3D printed and salt leached porous SMPU was observed to have the porosity in the range of 32.7–36% and pore sizes of

Total hip replacement (THR) is a surgical revolution that replaces an arthritic or accidentally damaged joint with a prosthetic joint. In spite of 100 years of operative history, the performance of a THR is critically challenged by implant fracture, biotribocorrosion, or osteolysis and aseptic loosening, limiting its life to merely 15–20 years. This leads to a revision of the hip replacement, which is very painful and more complex and takes longer operational time to replace some or all the parts of the original prosthesis with new ones. In this scenario, it is essential to evaluate the life of the implant to be used in a total hip arthroplasty (THA) before any invasive procedure, keeping the efficacy and safety of the patient in mind. However, it is an immense challenge for researchers to reproduce the wear mechanism and bodily fluid environment that is substantially equivalent to what a patient experiences physiologically. Other than the bearing material combinations for total hip arthroplasty (THA)—metal-on-metal, ceramic-on-polymer, metal-on-polymer, and ceramic-on-ceramic—the design of the joint and many other parameters govern wear performance and life. To imitate the in vivo loading and angular displacements under biolubricant, typical devices, called hip joint wear simulators, are employed to apply a set of motions and loads under lubrication conditions, which create an in vitro tribological environment comparable to those experienced by a THA under in vivo conditions. The hip joint simulator plays a most important role in validating the newly developed implants before use. Currently used simulators basically differ in parameters like single- or multistation(s), loading cycle, ball–cup relative position, degree of freedom, lubricant chamber, etc. This chapter reviews the simulator test results under standard protocols and explicates the requirement of preclinical assessment of wear and tribocorrosion in new hip implants before using them for THR.

Copper (Cu) gained its importance in several applications due to its attractive thermal characteristics. However, its applications are limited, wherever high strength and high thermal conductivity are desirable. Thus, an attempt was made to develop Cu/CNT composites having the improved mechanical and thermal properties. Initially, Cu/CNT composite powder was synthesized through molecular level mixing technique, where the functionalized 20–40 nm and 40–60 nm diameter CNT with varying concentrations from 0.25 to 1.0 wt.% with an increment of 0.25 wt.% were used. The powder was uniaxially compacted at 800 MPa and sintered in the range of 2–8 hr at 900 °C. The best characteristics of Cu/CNT composites obtained from the present study are as follows: Relative density (RD) – 89.1%, Hardness – 61.2 ± 0.58 VHN, Thermal conductivity – 343 W/mK and these characteristics obtained their maximum value at 0.25 wt.% CNT concentration and started to decrease irrespective of CNT diameter.

Highly conductive Copper/carbon nanotubes (Cu/CNT) composites are being explored in structural, electrical and thermal applications due to their requirement for prolonged usage in industrial applications. The conventional materials used to transport the heat and heat transfer fluid are required to be strengthened to increase their structural integrity and longevity in addition to increase their performances. Thus, the objective of present work is to study the influence of different diameters of CNT in improving the mechanical, electrical and thermal properties of Copper based composites by varying the sintering duration and CNT concentration in order to explore their usage in different potential applications. In this study, Cu/CNT composite powder was synthesized using molecular level mixing technique and consolidated by uniaxial compaction at 800 MPa followed by microwave sintering at 60, 75 and 90 min. Three diameters of CNT having the range of 10–20 nm, 20–40 nm and 40–60 nm were used with 0.25, 0.5, 0.75 and 1 wt.% concentrations to prepare the composites. The superior characteristics obtained from the present study are as follows: Hardness- 91.7 ± 1.59 VHN, Relative density– 90.9%, Electrical conductivity– 49.3 ± 0.1 MS/m, Thermal conductivity– 364.5 W/mK. It is concluded that any desired electrical and thermal characteristics of the composites can be obtained using the proposed methodology and the results obtained from the present study are at par with other high end technology.

The performance of Copper (Cu) can be enhanced by the addition of carbon nanotubes (CNT) as reinforcement in order to utilize it for prolonged industrial applications, where the mechanical and thermal properties are often appropriate for them. The aim of the current work is to develop the Cu/CNT composite products via novel molecular level mixing (MLM) technique followed by cold isostatic pressing (CIP) and microwave sintering (MW). Besides, the results are compared with the sample processed through uniaxial compaction (UA) followed by either conventional sintering (CS) or microwave sintering (MW) technique. The grain size of CIP-MW processed composites is found to be enhanced with size of CNT diameter, CNT content and sintering time in comparison to that of Copper. The maximum properties of Cu/CNT composites are obtained irrespective of the size of CNT diameter as follows: Relative density - 93.8%, Hardness - 83.2 ± 2.1 VHN, Electrical conductivity - 50.4 ± 0.2 MS/m and thermal conductivity - 372.8 W/mK. The thermal conductivity of CIP-MW processed Cu/CNT composites is found to have superior characteristics in comparison to that of UA-CS and UA-MW processing techniques and the reported results are at par with the highly expensive and high-end technique like spark plasma sintering.

Amputation is a surgical procedure to remove a part or limb from a body. Since World War II, limb amputations became more prevalent among war-affected soldiers, who returned to their normal lives through rehabilitation and training. Amputation also appeared to be a considerate solution for the casualties of accidents. Among the elderly, diseases such as diabetes and peripheral vascular disease result in amputation to prevent further spread of infection.

An attempt is made here to characterize thermal conductivity of water-based Al2O3 nanofluid and then use the same in a circular finned thermosyphon (TPCT) to measure its thermal performance. The concentration of Al2O3 nanofluid is varied within 0.05–0.25% by volume. The thermal conductivity of nanofluid is increased with concentration of Al2O3 nanoparticles as well as with temperature. A maximum of 26.7% enhancement of thermal conductivity is observed at 45 °C for 0.25% concentration by volume of nanofluid in comparison to that of de-ionized (DI) water. Variations of surface tension and contact angle of Al2O3 nanofluid are also compared with DI water. One of the smallest TPCT with different heat inputs (4 W, 8 W, and 12 W) and different inclinations (30 deg, 45 deg, 60 deg, and 90 deg) is tested for different concentration of Al2O3 nanofluid, which will find application in smaller electronic units. It is found that use of nanofluid decreases the wall temperature distribution of TPCT. Thermal resistance of TPCT decreases whenever TPCT is filled with nanofluid and a maximum of 36.4% reduction in thermal resistance is noted for 0.25% volume of nanoparticles at 4 W with an inclination of 60 deg. It is also found that performance of TPCT is higher at 60 deg inclination compared to other inclinations, especially for lower heat input.

Objective: The lower limb amputation is one of the major concerns for the amputee’s daily life and the trans-femoral (TF) amputation is being paid a lot of attention because of its functional requi...

India is currently importing different types of medical implants and devices, which cost about 0.65 million USD. Most of the imported implants and devices are found to be expensive and not suitable for Indian patients because of their design limitations. Thus, it is very much essential to develop indigenous devices at an affordable cost without compromising their functional activities. The chapter will discuss the design and development of patient-specific biomedical devices and implants as per ISO/ASTM standards in order to meet their individual requirements. In the specified area, the products being developed by our research team have been kept under two different categories namely implants and biomedical devices. Under the implant category, the products such as (i) ultrahigh molecular weight polyethylene-based acetabular cup, (ii) 3D printed shape memory polyurethane-based aneurysm coil, and (iii) different types of cerium-based anti-scavenging materials to absorb the excess reactive oxygen species (ROS) to preserve the residual hearing after cochlear implant fixation are being developed and tested. In case of biomedical devices, prosthetic and orthotic devices such as (i) polymer-based polycentric knee joint, (ii) dynamic foot, (iii) custom-made ankle-foot orthosis, (iv) suction and suspension incorporated socket for lower limb amputees, and (v) direct socket fabrication system are being developed and trialled. A discussion on the different materials including polymers, ceramic, and composites which are used to improve the performance of the above-discussed biomedical devices and implants will be deliberated in details.

The chapter proposes a Net collaborating system to establish a query-based disease rectification solution system for needy patients. Today, many developing countries are focusing on providing better rural healthcare. But the distance between rural areas and the hospitals has been a major issue in bringing better healthcare to rural masses. In this context, if usage of technology and Internet can create an interim system to identify urgency of situations and alert healthcare providers, better healthcare can reach the needy at the right time, thus reducing fatality and also outbreak of contagious diseases. A Net collaborating system establishes the urgency of a requirement by getting information through queries and routes the queries to the appropriate solution system. Connecting patients with appropriate healthcare experts will be done by mapping expertise and type of disease, thus reducing waiting time.

Poly(methyl methacrylate) (PMMA) nanocomposites containing nanoclay with and without compatibilizer (PMMA-g-MA) were prepared by melt blending followed by compression molding in order to investigate the rheological and flammability properties of developed nanocomposites. The rheological measurements at various temperatures and frequencies were performed using rheometer with parallel-plate geometry. The frequency sweep result revealed that storage modulus improved with the addition of nanoclay at lower frequency and gradually changed from liquid-like behavior to solid-like behavior due to the formation of percolating network structure. For all the samples, complex viscosity decreased as the temperature increased. Similarly, dynamic mechanical investigations exhibited a significant enhancement in storage modulus at lower temperature due to reinforcing effect of nanoclay. The flammability test also demonstrated that rate of burning was reduced by 37% with the addition of nanoclay.

A socket plays a vital role in giving the comfort to the amputees. However, the accumulation of heat inside the socket and its weight led to increase their metabolic cost. Hence, an attempt was made to increase the performance of the epoxy based sandwich composites to be used for the socket by reinforcing multiwalled carbon nanotubes (MWCNT), which was varied from 0.1 to 0.5wt%. It was homogeneously dispersed in epoxy to obtain the desired properties, where the enhancement of thermal conductivity, compressive strength and modulus of epoxy was observed to be 76.7%, 62.6% and 20.2%, respectively at 0.3wt% of MWCNT concentration beyond which the mechanical properties were found to be decreased. Hence, the epoxy, E-glass plain fabric, 2-10 layers of stockinet and 0.3wt% of MWCNT were used to prepare the sandwich composites. The flexural strength and thermal conductivity of 0.3wt% of MWCNT reinforced sandwich composites were found to be improved by 11.38±1.5% and 29.8±1.3% for the 4-10 layers and up to 10 layers of stockinet, respectively compared to unreinforced sandwich composites, which helped to reduce the weight of the socket and decrease the heat accumulation inside the socket. Thus, it is suggested to be explored for the application of socket in trans-femoral amputees to increase their comfort level by decreasing the metabolic cost.

Ultra-high molecular weight polyethylene (UHMWPE) has been used as a surface for acetabular in total joint replacements for the past 60 years. However, the performance of the implant is influenced by the increase in temperature because of the articulating motion and the contact asperities, which affects its longevity. The viscoelastic properties of multi-walled carbon nanotubes (MWCNTs) reinforced UHMWPE nanocomposites with respect to temperature and irradiation dose are not reported so far. Hence, an attempt was made to study the viscoelastic properties of UHMWPE by varying concentration of MWCNTs and intensity of irradiation dose. The test samples were subjected to sinusoidal loading in the temperature range of 30–80°C. Ultra-high molecular weight polyethylene nanocomposites were prepared at different concentrations of MWCNTs such as 0.5, 1.0, 1.5 and 2 wt-% using compression moulding process and the nanocomposites were subjected to 60Co gamma irradiation up to 100 kGy dose. The viscoelastic characteris...

Cerium and cerium-based oxides are found to be an important element in three-way catalytic converter (TWC). The effective utilization of TWC is found to be reduced due to thermal loading which results in structural deformation of ceria. Doping Zr4+ into the rare earth element can increase the oxygen storage capacity and thermal stability. Hence, an attempt was made to study the oxygen storage capacity and thermal stability of ceria by doping Zr4+ and Nd3+. Cerium-based nanocrystallite in the composition of Ce0.6Zr0.4−xNd1.3xO2 (0 ≤ x ≤ 0.4) was prepared by sol–gel synthesize technique with citric acid as a gel-forming agent. X-ray diffraction (XRD) result shows that doping Nd3+ into ceria lattice forms homogenous solid solution of cubic fluorite structure up to 25 % of substitute only. Doping higher amount of Nd3+ into ceria lattice leads to the formation of Nd2O3. Raman spectrum study confirms that oxygen storage capacity band is present in Ce0.6Zr0.4O2 and Ce0.6Zr0.3Nd0.13O2. The oxygen storage capacity was calculated through weight loss of the sample during the second heating cycle with cyclic heating from 30 to 800 °C in thermogravimetric analysis (TGA). The TGA study reveals that the oxygen storage capacity of Ce0.6Zr0.4O2 decreases after the substitution of Nd3+, which is due to the larger ionic radius of Nd3+ compared with that of Zr4+ and CeO2.

Interventional radiology technique (IRT) is being increasingly used to embolize the blood vessels or prevent the flow of blood into the diseased part of a blood vessel in a human body. Shape memory polyurethane (SMPU) has been identified as an alternate embolic agent for IRT, which can overcome vital issues such as non-target embolization, incomplete occlusion, coil migration, and others. However, its inherent lack of radiopacity and bioinertness restrict potential applications of it in IRT. The objective of the present work is to study the effect of combining SMPU and radiopaque filler materials on the mechanical, thermal, shape recovery characteristics, and radiopacity. Hybrid composite materials having Barium sulphate (BaSO4) nanoparticles and hydroxyapatite (HaP) nanoparticles in the SMPU matrix are fabricated using a twin-screw extruder, and their properties are compared with that of the composites containing only single filler. The addition of the filler in SMPU is not found to affect its shape-holding characteristics. However, the shape recovery characteristics of the hybrid composites are decreased by 20–30% during the 1st cycle, which was then recovered to more than 90% during the 2nd recovery cycle. It is observed that the shape recovery rate of the SMPU can be fine-tuned by changing its programming temperature. It is also noted that the tensile strength of composites is decreased with an increase of filler concentration due to their agglomeration and voids in the composites. In case of 10 wt% hybrid composites, the reduction of tensile strength is found to be in the range of 24–28% irrespective of individual filler concentration, and it showed better mechanical properties than individual filler at the same concentration. The radiopacity of the composites is observed to be increased with filler concentration, where BaSO4 played a dominant role in comparison to that of hydroxyapatite nanoparticles. Hence, the developed SMPU hybrid nanocomposites can be explored as embolic agents for IRT due to their suitable mechanical properties, actuation profiles, and enhanced radiopacity.

The development of polymeric nanocomposites for biomedical applications remains a major challenge in terms of tailored addition of nanoparticles to realize the simultaneous enhancement of fracture resistance and cell/blood compatibility. To address this, the present work has been planned to determine whether small addition of surface functionalized multiwalled-carbon-nanotube, MWCNT (

Energy transition from fossil fuels to renewable has been a case of debate in social, political, economic and environmental points of view owing to the long term impacts it has on populace and Governments. The energy transition requires infrastructural change for introduction, production and diffusion which takes decades to be developed. But the most important threat to the transition is the time and effort it takes to persuade the society for adaption. Many developed nations have shown improvement in the percentage of transition after a global movement took place in 2009 but still the larger part of the globe has not been able to adapt it. The paper compares various socio economic political and cultural factors affecting the transition in various countries both developing and developed. These perspectives are important for decision makers since they can adversely affect the intended benefits of any technology or at least slow down the transition.

Information systems on Agriculture can be a boon to any country, but for the farmers of India, particularly Tamilnadu, this can be the one which saves farmer's lives. But the farmers are to be given a big push towards using technology for their needs since the trust factor on technology among farmers is very low. This paper discusses about a persuasive technology method (PTM) developed to change the mindset of the farmers towards technology supported farming. The ICT system developed hass a website component and a mobile app component. The mobile app is linked to the website with details of marketing and farming accessory like dairy, organic products and farm machineries. Based on the requirement, the farmer can learn about the crops, marketing his products and by products or getting support for the field operations. Designing the persuasive technology method was done by choosing the different persuasive methods like promotion gifts, awareness get togethers and targeting the younger generation of the farming families. Effectiveness of the method chosen was tested in real time and metrics were analysed to bring out the best possible PTM.

Ultra high molecular weight polyethylene (UHMWPE) was reinforced by chemically treated multi walled carbon nanotubes (MWCNTs) up to 2.0 wt% and later subjected to gamma irradiation up to 100 kGy dose. The influence of MWCNTs on the hardness and wear resistance of UHMWPE was evaluated before and after the irradiation process. The hardness of UHMWPE was increased by 89% by homogeneous dispersion of 2 wt% MWCNTs and 100 kGy irradiation. Wear studies on the test samples revealed that the wear volume of unirradiated UHMWPE was reduced by 31%, 54% and 73% upon dispersing 2 wt% MWCNTs, 100 kGy irradiation and the combination of both, respectively. The surface morphology and topography of the wear tracks were examined to understand the wear mechanisms of UHMWPE and its composites. Though the wear mechanism observed in the polymer and composites under normal and irradiated condition is found to be the same, the severity of wear was found to be reduced for irradiated composites compared to unirradiated UHMWPE. The crosslink density (CLD) of composites was found to be higher than that of UHMWPE. It is concluded that the cumulative effect of the presence of MWCNTs and irradiation effectively increased the wear resistance of UHMWPE.

This paper deals on bio-fuel, consisting of used sunflower oil and transesterified - used sunflower oil blended with diesel. They are prepared and tested as a fuel in a direct injection (DI) single cylinder four stroke diesel engine. The main fuel properties of these fuels are measured, the engine performance characteristics are investigated and compared with that of diesel fuel. Fuels are separately prepared, blended and tested for determining the characteristics and combustion in a single cylinder diesel engine. The main fuel properties such as the specific gravity, density, flash and fire points of the blended fuels are measured. The engine performance is investigated and compared with that of diesel fuel. The experimental results showed that the specific gravity of the hybrid bio-fuels is decreased and close to that of diesel fuel. The experimental results also showed that the engine efficiency is closer to the values obtained from the diesel fuel. It is found that among the various blends, transesterifed used sunflower oil with diesel, gives better efficiency. In addition it is found that, the blend of diesel with used sunflower oil gives the lowest fuel consumption as compared to that of other blended fuels. Nomenclatures w1- weight of specific gravity bottle (g) w2- weight of specific gravity bottle + water (g) w3- weight of specific gravity bottle + sample (g)

An attempt is made to study the effects of gamma irradiation on multi walled carbon nanotubes (MWCNTs) with a specific focus on surface modification, structural changes and identification of irradiation generated defects on their surface. The as-received MWCNTs were chemically treated in order to attach required functional group on the surface and to remove traces of metallic impurities. The MWCNTs were then gamma irradiated at 25, 50, 75 and 100 kGy doses. Micro Raman analysis was performed on irradiated MWCNTs to estimate the irradiation induced defects on their surface, which revealed that the number of defects increased with dose. XRD analysis was also performed to observe the same and it was revealed that the MWCNTs were subjected to micro-straining. The selective area electron diffraction pattern revealed that traces of amorphous carbon were formed after irradiation. Various defects such as bending, variation of internal and external diameter, wall damages formed on the MWCNTs was verified using TEM. It is concluded that subjecting MWCNTs to irradiation sources has produced structural changes and defects on their surface which can influence the properties of nanocomposites.

Polypyrrole/thermally reduced graphene oxide (Ppy/TRGO) nanocomposites were synthesized via an in situ polymerization of pyrrole in the presence of TRGO in various proportions (1–5%). The synthesized nanocomposites were characterized by various techniques. SEM analysis clearly indicated the complete dispersion of TRGO in the Ppy matrix. The nanocomposite exhibited obvious improvement in the thermal stability and electrical conductivity in comparison with the pure Ppy. The aim of this study was to determine the rheological behavior of Ppy/TRGO nanocomposite at different mass ratio (100:1, 100:3 and 100:5%) and temperature (25–180 °C) by using a rotational mode in cone-plate method. The nanocomposite was found to exhibit a non-Newtonian and shear thinning behavior at both lower and higher temperature. The rheological results showed that the Ppy/TRGO nanocomposites are stabile, and does not deform at high shear rate and temperature. The shear stress ( τ , Pa) and viscosity ( η , Pa s) of the nanocomposites were increased with the addition of TRGO sheet into the Ppy. It was noted that TRGO sheets are effective material for the reinforcement of Ppy and the nanocomposite exhibit high flexibility compared with rigid pure Ppy.

The usage of cemented fixation for total hip replacement still exists for older people and patients having voids and irregular femurs. However, the huge difference between the mechanical properties of the cortical bone and bone cement led to inhomogeneous stress transfer in the stem/cement interface. Hence, an attempt was made in this direction to sort out the above mentioned problem by reinforcing the poly(methyl methacrylate) (PMMA) bone cement with single walled nanotubes (SWNTs). The SWNTs were functionalised with alkaline treatment, and the attachment of sodium ethoxide was confirmed by Fourier transform infrared spectroscopy. Later, the polymerisation was done along with the reinforcement of SWNTs, and the mechanical properties were evaluated using the nanoindenter. It is observed that the Young’s modulus and hardness of PMMA were found to be enhanced by 19 and 36% respectively at an optimum concentration of 0·15 wt-% SWNTs. It is concluded that the reinforcement of PMMA by SWNTs significant...

The usage of polymers is increased in order to replace the conventional metals because of their low cost and weight. As the processing technique of polymers plays a vital role in their properties, Polypropylene (PP) and multi walled carbon nanotubes (MWCNTs) were chosen as a matrix and reinforcement, respectively in order to confirm the effective processing method to prepare nanocomposites. The PP/MWCNTs nanocomposites with different concentration of reinforcement such as 0, 0.5, 1.0, 1.5 and 2.0 wt. % were prepared by melt mixing technique through (i) an injection molding (IM) process and (ii) the twin-screw extruder followed by an injection moulding process (TSE). It is observed that the mechanical properties of PP were found to be increased with MWCNTs concentration irrespective of the processing methods, where the optimum concentration was observed to be 1.5 wt. % of MWCNTs. It is also observed that the mechanical properties of polymer processed through TSE process was found to be less than that of the sample processed by IM process. However, an opposite trend was observed when the reinforcement was done. It is concluded that the PP/MWCNTs nanocomposites processed through TSE were found to have enhanced mechanical properties compared to that of the sample prepared through IM process.

The property of high oxygen storage capacity (OSC) of Ceria is an important component in three-way catalysts (TWC), which depends on the low reduction temperature, high surface area and stable crystalline structure. These are required to be improved using mixed oxides for the increased OSC of TWC. Though a good number of literature is available in Ceria-Zirconia mixed oxides, optimization of the composition of oxides based on OSC is very much limited. Hence, an attempt was made to optimize the composition of CexZr1-xO2 (0.4 x 0.8) (CZ) based on the OSC using thermogravimetric technique. The CZ solid solution was prepared by co-precipitation (COP) method using Ceria nitrate, and Zirconia oxy-choloride precursors, where the freshly prepared metal hydroxide precipitates were continuously stirred at 45 °C for 60 minutes followed by washing and drying to obtain the nanosized CZ particles. The formation of single nanocrystallite with less than 8 nm size solid solution was identified by XRD, and the same was confirmed by Micro Raman studies. It is observed that the trend of OSC in CZ solid solution was based on the ratio of Ce to Zr in the starting aqueous solution, where the OSC was found to be maximum at 1.5 and the corresponding OSC of the compound was about 0.14 μmol per gram of Ceria.

Property degradation of the medical grade polymers after gamma irradiation is the primary concern that limits longevity of them. Though the conventional antioxidant material helps to reduce the degradation but it limits the degree of crosslinking of the polymer. The objective of the present work is to study the influence of multi walled carbon nanotubes (MWCNTs) on restricting the degradation of mechanical properties of medical grade ultra high molecular weight polyethylene (UHMWPE) after its irradiation. UHMWPE was reinforced by chemically treated MWCNTs at different concentrations such as 0.5, 1.0, 1.5, and 2.0 wt%. The test samples were then subjected to Co⁶⁰ gamma irradiation with an integral dose of 25, 50, 75 and 100 kGy in air. The mechanical properties of irradiated samples were evaluated within 10 days, 60 and 120 days after irradiation. It was observed that the mechanical properties of virgin UHMWPE and nanocomposites were enhanced immediately after irradiation but they were found to be reduced at later stages. It was also observed that the presence of MWCNTs limited the ageing degradation of the mechanical properties of UHMWPE. Raman spectroscopic and TEM studies confirmed the formation of irradiation induced defects on the MWCNTs. Electron spin resonance studies showed that the relative radical intensity of virgin UHWMPE was reduced significantly with an increase of MWCNTs concentration confirming the radical scavenging ability of them. It is concluded that MWCNTs restricted the ageing degradation of irradiated UHMWPE.

A thrust on the enhancement of the mechanical properties of ultra high molecular weight polyethylene (UHMWPE) to enhance its longevity has taken a new direction with the advent of nanomaterials and carbon nanotubes. In the present work, UHMWPE was reinforced by chemically treated multi walled carbon nanotubes (MWCNTs) at different concentrations such as 0.5, 1.0, 1.5, 2.0, 2.5 and 5 wt%. The mechanical properties of nanocomposites were studied using a Nanoindentation technique and micro-tensile testing. It is observed that the toughness, ultimate stress, fracture strain, and yield stress of medical grade UHMWPE were enhanced by 176, 93, 70, and 44%, respectively at an optimum concentration of 2 wt% MWCNTs reinforcement. The mechanism for the enhancement of mechanical properties was confirmed by the micro-Raman and calorimetric technique. The reduction of the mechanical properties of nanocomposites beyond optimum concentration of MWCNTs was confirmed by the rheological studies. The generation of microvoids on the nanocomposites was verified by the scanning electron microscopy technique. Nanoindentation characteristics revealed that the surface hardness of UHMWPE was increased by 75% by the reinforcement of 2 wt% of MWCNTs. The Young's modulus obtained at the surface of nanocomposites was observed to be 9.8% higher than that of surface layer removed sample for 2 wt% nanocomposite. It is concluded that the presence of MWCNTs enhanced the mechanical properties and surface properties of medical grade UHMWPE.

Conventional fluids used for heat transfer applications in automobiles limit the performance enhancement and compactness of the heat exchangers. These problems can be overcome by using the technology of nanofluids. The objectives of this work are to prepare nanofluids and to study their dynamic viscosity and thermal conductivity. Chemically treated carbon nanotubes (CNTs) were added with ethylene glycol (EG) and sonicated using a bath sonicator to have a homogeneous dispersion of CNTs in EG. In this study, the nanofluids were prepared with different concentrations of CNTs varying from 0.12 to 0.4 wt%. The dynamic viscosity of nanofluids was measured using a rheometer over a temperature range of 25°C to 60°C. It was observed that the viscosity of nanofluids decreases with an increase of temperature and enhances with CNT concentration. The nanofluid follows the characteristic behavior of Newtonian fluids. A linear rise in thermal conductivity of ethylene glycol was observed with an increase of CNT concentra...

Sterilization of implants and other clinical accessories is an integral part of any medical application. Although many materials are used as implants, polyethylene stands unique owing to its versatility. Carbon nanotubes are being used as a filler material to enhance the properties of polyethylene. However, the role of multi walled carbon nanotubes (MWCNTs) as an effective antioxidant and radical scavenger in resisting the deteriorating effects of sterilization is yet to be studied in detail. The present work is aimed to investigate the mechanical properties and oxidation stability of irradiated high density polyethylene (HDPE) reinforced by MWCNTs with various concentrations such as 0.25%, 0.50%, 0.75% and 1.00 wt.%. The composites were exposed to 60Co source in air and irradiated at different dosage level starting from 25 to 100 kGy and then shelf aged for a period of 120 days prior to investigation. The loss in toughness, Young’s modulus and ultimate strength at 100 kGy for 1 wt.% MWCNTs composite were found to be 21.5%, 20.3% and 19.2%, respectively compared to that of unirradiated composite. FTIR and ESR studies confirmed the antioxidant and radical scavenging potentialities of MWCNTs with increased concentration and irradiation dosage. It was found that by the addition of 1 wt.% MWCNTs into virgin HDPE, the oxidation index of the composite at 100 kGy was decreased by 56.2%. It is concluded that the addition of MWCNTs into polyethylene not only limits the loss of mechanical properties but also improves its post irradiation oxidative stability.