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Aluminum impregnated zinc oxide engineered poly(vinylidene fluoride hexafluoropropylene)-based flexible nanocomposite for efficient harvesting of mechanical energy
Get PDFConfronting the depletion of fossil fuel energy as well as pollution generated from chemical batteries, associated with the increasing number of electronic equipment and the internet of things, results in a high requirement of lightweight, low cost, sustainable, and durable power devices. Currently, a flexible and self-powered piezoelectric energy harvester (PZEH) is a suitable alternative, which may be easily integrated with small electronics to realize real-time sustainable energy generation. Therefore, a novel PZEH has been fabricated at room temperature (30 degrees C) using Al-doped ZnO (Al@ZnO) incorporated poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) nanocomposites. Al@ZnO enables nucleation of electroactive phase within PVDF-HFP (10PALZO) exhibited polarity at a much higher fraction (FEA] >90%) compared to neat PVDF-HFP (FEA] = 63.8%). Piezoelectric energy harvesting capability of the device has been investigated under gentle repeated human finger tapping. Optimized Al@ZnO-PVDF-HFP composite (with 10 wt% loading)-based PZEH delivered a high value of open-circuit output voltage similar to 22 V. Such high output value infers a good energy conversion efficiency of the device. For further enhancement of the performance of the device, the 10PALZO nanocomposite was placed under a high electric field of 2.4 MVcm(-1) resulting in an open circuit output voltage of similar to 26 V. In addition to that, the proposed nanocomposite exhibits a good energy storage efficiency (10PALZO-P) which further enhanced to 111.2 mu Jcm(-3) (at 1 Hz) after poling under an electric field 2.4 MVcm(-1). This increment in the output value is due to the improved polarization induced by Al@ZnO within the PVDF-HFP matrix. These results highlight that the filler can efficiently maximize the device performance thereby developing new efficient energy harvesting materials
In vivo osteogenesis of plasma sprayed ternary-ion doped hydroxyapatite coatings on Ti6Al4V for orthopaedic applications
No full textPlasma-sprayed hydroxyapatite (HAp) coated metallic implants for orthopaedic and dental application have some inherent shortcomings like brittleness, low fracture toughness, poor tensile strength, slow osseointegration rate and poor antimicrobial properties. To mitigate these shortcomings, we have envisaged and developed specific compositions of Sr, Zn, Ag and F multi-ion doped HAp earlier employing Taguchi statistical principle. The aim of the present investigation is to study the feasibility of plasma spray-coated metallic implants focusing specifically on two specific compositions {based on Sr-Zn-F-HAp - (D1HAp-Ti) and Sr-Zn-Ag-HAp (D2HAp-Ti)} as envisaged earlier. Performance of the above compositions was studied and compared with no coating and pure HAp coated implants. The comprehensive study included detailed material development and characterization up to in vivo pre-clinical trial. Finally, free-flowing granules (75-104 mu m) of multi-ion doped HAp were used for plasma spray coating on Ti6Al4V substrate and analyzed the effect of multi-ion doping on HAp. Interestingly, XRD showed presence of HAp as main phase in all cases except undoped HAp coating where secondary phases like alpha-TCP and beta-TCP could also be traced. FTIR study confirmed basic functional groups of HAp for all cases. Scratch adhesion of coating as well as microhardness was found to be increased substantially by multi-ion doping The result from corrosion resistance and SBF immersion test clearly exhibited multi-ion doped HAp coated implant's superior property co over undoped HAp coating. In vivo implantation of these implants in animal femur defect model and follow up investigation up to 2 months with micro-CT, histology, radiology and fluorochrome labelling showed enhanced osseointegration of multi-ion doped samples as compared to bare, and control samples. . Hence, a multi-ion doped HAp coated titanium substrate can be used as a promising implant coating material for orthopaedic applications
Fabrication of Fe doped reduced graphene oxide (rGO) decorated WO3 based low temperature ppm level acetone sensor: Unveiling sensing mechanism by impedance spectroscopy
No full textChemiresistive MOS-based acetone sensing device is a futuristic pathway for non-invasive diagnosis of diabetes. Although their potential deployment is restricted till now due to lack of selective, low temperature operated ppm-level sensors. In this work, we demonstrated synthesis of iron doped reduced graphene oxide (rGO) decorated WO3 nanocomposites in a facile, environment friendly wet chemical sol-gel process. The as synthesized nanocomposites were comprehensively characterized by using different characterization techniques. A maximum-78% sensing response was obtained for the optimized composition of-10 wt% Fe doped 3 wt% rGO decorated WO3 based thin film (thickness-700 nm) sensor towards-10 ppm acetone gas. This sensing performance was observed at comparatively low working temperature of -130 ? with fast response (-20 s) and recovery (-75 s) time. The efficacy of the fabricated sensors was established by their capabilities to sense a very low concentration of -1 ppm acetone under similar working environment. Further illustration of versatility of the sensors revealed that, the sensors could be able to manifest a repeatable and reproducible sensing performance with prolong stability and superior selectivity for acetone over other interfering gases. The acetone sensing mechanism was illustrated with the help of electron depletion model and impedance spectroscopy study. Impedance spectroscopy quantifies different electrical properties and enlightens the smooth electronic transition mechanism between analyte and sensing material
Study and Realization of Nanocomposite Thin Film Material-based Fiber Optic Sensor for the Detection of Gases and Chemical Species
No full textThe present Ph.D. thesis entitled,” “Study and realization of nanocomposite thin based fiber optic
sensor for the detection of Gases and Chemical Species”, demonstrates the development of thinfilm
based fiber optic sensors. In the Ph.D. thesis work, various photonic materials viz, Au coated
ZnO, Ag-doped ZnO, Bi-doped ZnO, and Ag-doped TiO2 have been hydrothermally prepared over
modified fiber substrate for the development of the fiber optic sensors. The theoretical simulation
of sensing parameters viz evanescent field, penetration depth, Modal field analysis, and optical
absorption have been carried out. The clad thickness (2-5μm) is essential to developing a fiber
optic sensor which was simulated by MATLAB. In the thickness range, penetration depth (pd ≈
8.939) was found optimum at the incident angle
Coalash as sustainable material for low energy building
No full textSand, which is a naturally occurring soft mineral ranks second after water, as far as consumption is concerned globally. Due to rapid infrastructural development
worldwide, particularly in Asian region, the rate of natural formation of sand has been found to be outpaced by rate of consumption, causing greater ecological imbalances.
Coalash, an industrial waste from thermal power plants are polluting in nature, and legacy ash in huge proportion without proper utilization is posing a serious threat to
the environment. It was ideated to replace sand by coalash in concrete and mortar mix, and to evaluate the physical and thermal properties for its suitability in low energy building construction. Without compromising strength criteria, thermal transmittance value is found to be reduced up to considerable extent, which resulted lesser cooling
requirement with added economic benefit. This medium technology application could be one of the economic pathway towards Near Zero Building Construction
Optimization of oxygen plasma based etching of single layered graphene through Raman and FESEM characterization
No full textGraphene field-effect transistors (GFETs) show high electron transfer rates, high charge-carrier mobility, low electrical noise levels and flexibility of surface functionalization, which are useful to realize the sensors for various applications. The key challenge is to develop the processes to fabricate a uniform array of GFETs devices. In this paper, single-layered graphene (SLG) was synthesized on copper (Cu) substrate using chemical vapor deposition (CVD) followed by its successful transfer over silicon (Si) substrate. To realize an array of graphene-based devices/ sensors, the process of oxygen plasma based clean etching of SLG was optimized. The Raman and Field Emission Scanning Electron Microscope (FESEM) characterizations ensure the complete etching of SLG in 240 s using 200 W, RF (13.56 MHz) power. Optimized SLG etching would help to fabricate an array of GFETs as a biochemical sensor platform. (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Advances in Nanomaterials and Devices for Energy and Environment
Performance assessment of the indigenous ceramic UF membrane in bioreactor process for highly polluted tannery wastewater treatment
No full textThe present study evaluates the performance of an indigenously developed ceramic ultrafiltration (UF) membrane in a lab-scale membrane bioreactor (MBR) process to treat real tannery effluent with varying organic loading (1500-6000 mg/L). UF membrane was prepared by the coating of bentonite clay on tubular clay-alumina macroporous support. The membrane surface was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, BET adsorption-desorption, contact angle measurement, and atomic force microscopy. In the side-stream MBR process, sewage sludge from a local sewage treatment plant was used as an activated sludge source with a constant sludge retention time of 30 days. Membrane filtration was performed in cross-flow mode using a single-channel membrane module. Artificial neural network (ANN) modeling tool was used to analyze the influence of various independent input variables, namely, the hydraulic retention time (4-10 h), mixed liquor suspended solid (MLSS) concentration (2-8 g/L), and influent COD concentration (1500-6000 mg/L) on COD removal (%) with feed-forward backpropagation method. Membrane study was done at a transmembrane pressure of 4.3 bar and feed flow rate of 7.5 L/min to observe the flux declination and fouling of the UF membrane with time. Average COD and BOD concentrations obtained in the treated effluent were 147.56 and 31 mg/L, respectively, and chromium concentration was < 0.1 mg/L; thus, treated effluent quality was found to be suitable for industrial recycling purposes apart from the safe environmental discharge. An in-depth study was undertaken to understand the removal mechanism in the MBR process, nature and extent of membrane fouling, changes in the morphology of the UF membrane, surface wettability, and surface topology by detailed surface characterization of the membrane pre- and post-filtration
Cellulose-ceramic composite flexible paper separator with improved wettability and flame retardant properties for lithium-ion batteries
No full textIn quest of developing sustainable separator for lithium-ion batteries (LIBs), this research focuses on functionalization of low cost cellulose based commercial paper using duo-polymer and nano-SiO2 by designing a facile aqueous based industry friendly wet-coating process. Unlike commercial plastic based polyolefin separators (polypropylene/polyethylene), the developed paper separator shows superior thermal stability > 200 degrees C without dimensional shrinkage, excellent electrolyte wettability (147%) with zero contact angle, quicker electrolyte saturation and satisfactory mechanical strength (34.86-38.31 MPa). The electrochemical performance carried out in 2032 coin cells using fabricated paper separators shows comparable performance to that of commercial polypropylene (PP) based separator at different current densities of 0.05-0.4 mA/cm(2) with excellent columbic efficiency (> 96%) and good capacity retention on cycling. The developed separator is found to be compatible with most of the commercial electrodes (MCMB, -LiCoO2, -LiFePO4) used in today's LIBs. The functionalized cellulose-ceramic composite paper separator shows excellent flame retardant properties by offering an added safety features for its successful use in lithiumion batteries
Copper and cobalt doped bioactive glass-fish dermal collagen electrospun mat triggers key events of diabetic wound healing in full-thickness skin defect model
No full textThe wounds arising out of underlying hyperglycemic conditions such as diabetic foot ulcers demand a multi-functional tissue regeneration approach owing to several deficiencies in the healing mechanisms. Herein, four different types of electrospun microfibers by combining Rohu fish skin-derived collagen (Fcol) with a bioactive glass (BAG)/ion-doped bioactive glass, namely, Fcol/BAG, Fcol/CuBAG, Fcol/CoBAG, and Fcol/CuCoBAG was developed to accelerate wound healing through stimulation of key events such as angiogenesis and ECM re-construction under diabetic conditions. SEM analysis shows the porous and microfibrous architecture, while the EDX mapping provides evidence of the incorporation of dopants inside various inorganic-organic composite mats. The viscoelastic properties of the microfibrous mats as measured by a nano-DMA test show a higher damping factor non-uniform tan-delta value. The maximum ultimate tensile strength and toughness are recorded for fish collagen with copper doped bioactive glass microfibers while the least values are demonstrated by microfibers with cobalt dopant. In vitro results demonstrate excellent cell-cell and cell-material interactions when human dermal fibroblasts (HDFs) were cultured over the microfibers for 48 h. When these mats were applied over full-thickness diabetic wounds in the rabbit model, early wound healing is attained with Fcol/CuBAG, Fcol/ CoBAG, and Fcol/CuCoBAG microfibers. Notably, these microfibers-treated wounds demonstrate a significantly (p < 0.01) higher density of blood vessels by CD-31 immunostaining than control, Duoderm, and Fcol/BAG treated wounds. Mature collagen deposition and excellent ECM remodeling are also evident in wounds treated with fish collagen/ion-doped bioactive glass microfibers suggesting their positive role in diabetic wound healing
50 cm of Zirconia, Bismuth and Silica Erbium-doped Fibers for Double-pass Amplification with a Broadband Mirror
Get PDFErbium-doped fiber amplifiers (EDFAs) have saturated the technological market but are still widely used in high-speed and long-distance communication systems. To overcome EDFA saturation and limitations, its erbium-doped fiber is co-doped with other materials such as zirconia and bismuth. This article demonstrates and compares the performance using three different fibers as the gain medium for zirconia-erbium-doped fibers (Zr-EDF), bismuth-erbium-doped fibers (Bi-EDF), and commercial silicaerbium-doped fibers (Si- EDF). The optical amplifier was configured with a double-pass amplification system, with a broadband mirror at the end of its configuration to allow double-pass operation in the system. The important parameters in amplifiers such as optical properties, optical amplification and noise values were also examined and discussed. All three fibers were 0.5 m long and entered with different input signals: 30 dBm for low input and 10 dBm for high input. Zr-EDF turned out to be the most relevant optical amplifier as it had the highest optical gain, longest transmission distance, highest average flatness gain with minimal jitter, and relevant noise figures suitable for the latest communication technology