B. C. Yadav

EXPERIMENTAL INVESTIGATIONS ON NANOSIZED FERRIC OXIDE AND ITS LPG SENSING

Nanosized particles of α-Fe2O3 in the range of 17–64 nm were synthesized via hydroxide precipitation. The synthesized powder was investigated by XRD employing CuKα radiation and 2θ geometry. SEM images show the nanosheet like morphology. The pellet of this sensing material was made by hydraulic press under a uniaxial pressure of 616 MPa. The LPG sensing properties of α-Fe2O3 were investigated at room temperature for different exposure times of LPG. A maximum value of sensitivity and sensor response were found 3 and 213%, respectively for an exposure time of 300 s. Electrical properties of α-Fe2O3 in air were also investigated by measuring temperature–resistance (R–T) characteristics and plotting them as Arrhenius plot. Activation energy was calculated by thermal resistance method and found to have a value 1.07 eV.

Efficacy of xanthan based chlorhexidine gel as an adjunct to scaling and root planing in treatment of the chronic periodontitis

Aim: The aim of this study was to evaluate the clinical effectiveness of locally delivered xanthan-based Chlosite® gel as an adjunctive therapy to scaling and root planing in treatment of chronic periodontitis. Materials and Methods: In a randomized controlled clinical study, 30 patients were selected. Pocket depth between 5 and 7 mm was selected and each patient had two sites on the same side of the mouth. A total of 30 control sites were scaled and root planed and 30 test sites were scaled and root planed and Chlosite® gel was added. The clinical parameters, probing depth (PD), clinical attachment level (CAL), plaque index (PI) and bleeding on probing (BOP), gingival index were recorded at baseline, 6 weeks, 3 months and 6 months. Statistical Analysis: Paired/unpaired t-test was used, significance was placed at 5% level of significance, i.e., P < 0.05 was considered as a significant. Results: From baseline to a period of 6 months, significant difference was found between test and control group for PD, CAL, PI and BOP, P value being PD (P = 0.002), CAL index (P = 0.014), respectively. Conclusion: Subgingival injection of xanthan-based Chlosite® gel adjunct with scaling and root planing appeared to cause significant improvement compared with scaling and root planing alone in persons with chronic periodontitis.

Synthesis and characterization of nanostructured MnO2–CoO and its relevance as an opto-electronic humidity sensing device

Metal carboxylates are widely used in science and technology and have been the subject of intense studies due to the practical importance of their products. The present paper reports the synthesis of MnO2–CoO using metal carboxylates as precursors and the effect of humidity on the transmitted power through its thin film at room temperature. The refractive index of the material was found to be 1.445930 and the peak obtained from the photoluminescence spectra lies in the visible region. TEM reported a minimum grain size of ∼5.7 nm and SAED confirmed the crystalline nature of the material, which was further confirmed by XRD. Fluorescence characteristics also confirmed the low dimensionality of the material. The film was then investigated using SEM which exhibited the porous morphology. Through UV-Vis spectroscopy, it was found that the absorption of the film takes place in the UV region and the optical band-gap was observed to be 3.849 eV from the Tauc plot. The film was employed as a transmission based opto-electronic humidity sensor. Average sensitivity was found to be ∼2.225 μW/% RH with response and recovery times of 47 s and 59 s respectively. Experiments were repeated and the reproducibility of result was found to be ∼89%.

Fabrication and characterization of ZnO-TiO2-PANI (ZTP) micro/nanoballs for the detection of flammable and toxic gases

The present paper reports the in-situ chemical polymerization of nanocomposites thin film composed by titanium dioxide (TiO2), zinc oxide (ZnO) and polyaniline (PANI). It was found that nanocomposites sensor is highly selective and shows response to low concentration. To improve the sensing response characteristics of ZT thin film, PANI is incorporated. Thin film based LPG sensor of ZnO-TiO2-PANI composite was fabricated by spin coating of ZnO-TiO2 nanoparticles doped with PANI over inter digital electrodes (IDEs). The thin film was characterized by using XRD, SEM, TEM, UV-vis, BET and FTIR. It was also tested for gas sensing properties of LPG/NO2 which are well known flammable and toxic gases. The measured response for ZnO-TiO2-PANI based sensor was 87 for 2000 ppm of LPG and 412 for 20 ppm of NO2 at room temperature towards other testing gases together with Acetone, IPA, NH3 and CO2.

Nanostructured ferrites as room temperature humidity sensor

N including quantum dots, fullerenes, nanoparticles (zero dimension), nanotubes, nanowires, nanofibrils (one dimension), and graphene (two dimension) possess intriguing physical, chemical and biological properties. As a consequence, these materials form the basis of many interdisciplinary studies, where scientists have been inspired by self-assembly processes occurring in nature to construct advanced nanomaterials with applications in many fields. Self-assembly involves the organization of molecules into highly ordered structures through specific, local interactions among the components, without any external direction. Weak interactions, such as Van der Waals, electrostatic, and π-π interactions, as well as hydrogen bonding, and halogen bonding can lead to all kinds of challenging self-assembled nanostructures. The hierarchical structures of many peptides are attributed to self-assembly, therefore, could potentially act as building blocks for new materials with significant functionalities and a range of biological functions. In our recent work, non-covalent interactions including hydrogen bonding, hydrophobic interaction and electrostatic interaction were employed to modulate the peptide assembled nanostructures. We could successfully realize the peptide assembly transition from nanospheres to nanofiber by tuning hydrogen bond and hydrophobic interaction; furthermore, two dimension peptide nanopatch could be constructed instead of nanofiber by introducing the terminus intermolecular hydrogen bonding between the peptide and small molecules. The electrostatic interaction was proved to play an important role in peptide self-assembly and disassembly. Furthermore, it is significant to be addressed that the mechanical properties of peptide assemblies do changing after the nanostructure transition of peptide occurred. These peptide-based nanostructures could potentially be applied to be a candidate of biomaterials with potential importance in a wide range of technological applications.Z oxide (ZnO) nanoparticles (grown in the template of folic acid) are biologically useful, luminescent material. It can be used for multifunctional purposes, such as biosensor, bioimaging, targeted drug delivery and as growth promoting medicine. Though, ZnO is categorized as: “generally recognized as safe” (GRAS) but ZnO nanoparticle system may be cytotoxic. ZnO nanosystem could be of important relevance in the context of nanomedicine, where targeted treatment of biological systems at molecular level is a necessity. ZnO quantum dots with their surface modification and bio-conjugation for selective destruction of tumor cells and their potential use for drug delivery applications is the cardinal issue of this presentation..Nano-sized particle incorporation into metal matrix for fabrication of advance surface coatings find variety of applications in surface protection techniques. Al 2 O 3 , Cr 2 O 3 and SiO 2 nanoparticles have been codeposited with Zn using electrodeposition process to produce Zn nanocomposite coatings. The fabricated coatings were characterized using Scanning Electron Microscope affixed with Energy Dispersive Spectroscopy and X-ray diffractometer. The mechanical and tribological properties of the coatings were investigated using diamond microhardness indenter and dry abrasive wear tester. Zn-10g/L Cr 2 O 3 nanocomposite exhibited the highest microhardness of 228 HV and Zn-5g/L Al 2 O 3 nanocomposite possessed the highest corrosion resistance and lowest wear loss. Zn-5g/L SiO 2 nanocomposite showed good stability as compared to other composite coatings. The incorporation of the nanoparticles of Al 2 O 3 , Cr 2 O 3 and SiO 2 induce grain refinement and modify crystallographic orientation of Zn matrix. Zn-5g/L Al 2 O 3 and Zn-5g/L SiO 2 proved to be better coatings which can find variety of industrial applications where both mechanical and electrochemical properties are required.The existence of vibrations in undesired parts of mechanical machinery, civil structures, aerospace and automotive components,will cause overall setback and efficiency reductions in processes when the above parts are used. Hence is advising to completely get rid of the unnecessary vibrations or reduce them to a minimum possible value. This experiment is an effort to reduce these vibrations using Magneto Rheological fluids. A Magneto Rheological fluid provides viscous damping. The damping factor increases when a magnetic field is applied and is multiplied as the strength of the magnetic field is more, also the natural frequency of the body under test changes from to a value which is different from the initial value. This technique was utilized and a three layered MR fluid sandwich beam was fabricated. This beam was subjected to testing and analysis under both undamped and damped conditions. The controllability of variations in the various dynamic parameters like natural frequencies, vibration amplitudes and damping factors were observed. A reduction is natural frequency of beam was obtained in the presence of MR fluid under magnetic field, from 550 Hz to 300 Hz. Keywords: Magnetorheological fluid, MRFluid sandwich Beam, Natural frequency, Damping factor, Damping coefficient.A perovskite-like phase, K3B6O10Cl exhibits a large second harmonic response about four times that of KH2PO4 (KDP) and is transparent from the deep UV (180 nm) to middle-IR region. A high quality single crystal of K3B6O10Cl with dimensions up to 30 × 15 × 7 mm3 was successfully grown by the top-seeded solution growth method. Crystal morphologies and growth habits of K3B6O10Cl grown with seeds oriented along [101] and [211] were studied, and the best growth direction was obtained., The refractive indices of the crystal were measured by the minimum deviation technique and fitted to the Sellmeier equations. The nonlinear optical coefficients have been determined by the method of Maker fringes at λ=1064 nm. The suitable nonlinear optical coefficients as well as comparatively easy crystal growth make the K3B6O10Cl crystal a promising candidate for NLO materials.A carbon and fiberglass are the two mostly studied materials in air filtration industry due to their good performance with associated low cost. The advancement in the field of nanoscience and nanotechnology produced materials with improved properties than conventional materials. Nanofibers are one of the nanotechnology products, which have been explored for applications such as healthcare, water, energy, electronics, catalysis, environmental, air filtration, bioengineering and biotechnology. Pores and pore size distribution of nanofibers can be easily tunable. Recently, they have been explored in various air filtration products such as high efficiency particulate absorption (HEPA) filters and so on. In this talk, various nanofibers that are electrospun and deposited on HEPA filters, process variation, additives addition, and their performances, challenges faced and their potential application in air filtration industry will be presented.O (OA) and meniscus injury are often met from injury and aging. In the USA alone, approximately 50 million people are affected by OA, and over 50% among them require replacing total joints, which cost approximately

P1.0.5 Comparative humidity sensing based on Fe2O3 synthesized via different methods

15 billion per year. Tissue engineering (TE) approach to cartilage regeneration has promises to repair damaged or diseased cartilage. Biodegradable scaffolds as one of key elements in TE are expected to offer a complex biological microenvironment mimicking with native tissue to promote cell ingrowth and tissue regeneration. However, current scaffolds cannot simulate the complex microenvironment of native cartilage. To the end, our group developed a biodegradable extracellular matrix (ECM) hydrogel derived from pig cartilages. The hydrogel contained complex components including collagen, glycosaminoglycan, growth factors and peptides, which were mimetic with biological components in the cartilage. This hydrogel solution was flowable at 4oC and formed a solid hydrogel at a body temperature, which is appropriate for non-invasive surgery. The mechanical properties of the hydrogels could be tuned by altering ECM concentration. The chondrocytes survived and proliferated inside the hydrogel with a round shape due to a good cellular microenvironment. The hydrogel solution was easily injected into a mouse subcutaneous model and formed a solidified hydrogel in vivo. No severe immunogenetic response was observed till to 7 day implantation, indicating a good biocompatibility. The attractive injectability and biomimetic complexity showed that the cartilage-derived hydrogel would be a good candidate to be applied for cartilage regeneration.T development of silver nanoparticle (AgNPs) as a potent alternative to conventional antibiotics has been extensively investigated over the last decades. However, due to the prominent cytotoxic effect of silver on mammalian cells, there is always strong motivation to develop alternative technology that can compact bacterial infection without affecting the mammalian cells. Capping AgNPs with appropriate functional groups and incorporating them into a polymeric matrix is a feasible alternative to overcome these limitations. AgNPs with different chemical structures (nanocapsules and nanoparticles) and functionalities (polymer, lipid, and starch) were synthesized. To demonstrate application as antibacterial coatings, the stabilized AgNPs were then immobilized onto model surfaces made of a thin layer of allylamine plasma polymerized film. This substrate-independent technique preserves the AgNPs functionalities for a longer period of application time. All fabricated surface coatings exhibited superior antibacterial activity against four important Gram-positive and Gram-negative pathogens. This study further aimed to focus on investigating the effects of AgNPs surface components on delivery of engineered AgNPs from the coatings into the human fibroblast cell as well as bone marrow derived macrophages (BMDM). Most of the surfaces did not affect BMDM function or viability and demonstrated no toxicity toward fibroblast cells, except for lipid coated nanosilvers. Therefore, the chemical structures of nanoparticles significantly affect the coatings’ antibacterial, biofilm prevention and biocompatibility capabilities. We believe that such biocompatible nanostructures are of potential interest for various biomedical applications such as smart drug carriers and antibacterial coatings for medical devices and wound dressings.I order to develop compliant seal systems for SOFCs operating in the temperature range of 800-950°C, this project has focused on iterations in materials systems. The materials consisting of composites of a base glass with appropriate ceramic components in order to identify a stable sealing system with adequate and acceptable thermal characteristics, such as, the viscosity and coefficient of thermal expansion. Appropriate viscosity was targeted to ensure good flow behavior of the glass at temperatures where fuel cells operate and sealing effects are required. Viscosity variation in the composites was brought about by the selection of ceramic additives; a large number of candidates ranging from phase pure alumina, magnesia, ceria and barium zirconate, to ceria doped with 10 mole % gadolinium oxide (GDC). SCN1 glass (trade name of sealing glass developed by SEM-COM) was used as the base component, whose composition was such as to provide a CTE match with the SOFC system (in the RT-Tg range), when composited with a second ceramic phase. Additives in both nanoand micro-scale dimensions (as fine powders or in the form of fibers) were introduced mainly to block the bubbles from moving but also to make the composite structure stronger. In addition, their role was also to inhibit the growth of air bubbles within the glass matrix and to or prevent their coalescence during long soak-time at 850°C, with the goal of eliminating or minimizing the CTE drift in the resultant glass composition. No reaction between SCN1 glass and the GDC additives was discerned. Moreover, the bubbles remained small and did not move or coalesce. The CTE of the GDC composites was very close to the targeted value and not change significantly when aged up to 232 h at 850°C in air.

Synthesis of ZnO nanopetals and its application as NO2 gas sensor

Ferric oxide nanomaterial was synthesized by two hydrothermal precipitation methods as B1 and B2. Pellets as sensing elements were subjected to specially designed humidity chamber and variations in resistance with relative humidity (%RH) were measured. Pellet prepared from B2 reveal maximum average sensitivity 6.61 MΩ/%RH. Structural analysis confirmed the formation of Fe2O3 with α-phase and rhombohedral structure. Average crystallite size of materials for B1 and B2 were found 40 and 18 nm respectively. SEM images show more porosity (largest surface area) of material for B2. TEM image of material for B2 shows uniform distribution of particles having average particle sizes are around 2 nm. Optical and thermal properties were investigated by using UV-visible absorption spectroscopy and Differential scanning calorimetric techniques.