654 research outputs found
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Prediction of Surface Roughness Using Artificial Neural Network in Single Point Diamond Turning
No full textIn manufacturing industries, manufacturers focused on the quality and productivity of the product. To increase
the productivity of the product, computer numerically machine tools have been implemented during the past decades. Surface roughness is one of the most important parameters to determine the quality of product. The mechanism behind the formation of surface roughness is very dynamic, complicated, and process dependent. Several factors will influence the final surface roughness in a Diamond turning operations such as controllable factors (spindle speed, feed rate and depth of cut) and
uncontrollable factors (tool geometry and material properties of both tool and work piece). Some of the machine operator using trial and error method to set-up machine cutting conditions. This method is not much effective and efficient and the achievement of a desirable value is a repetitive and empirical process that can be very time consuming. In order to solve the problem, a surface prediction technique based on artificial neural network prediction models is developed to predict the machining response for different input
machining parameters. Thus, manufacturers can improve the quality and productivity of the product with minimum cost and time
Nanostructured polyaniline films on silicon for sensitive sensing of ammonia
No full textSilicon (Si)–nanopolyaniline (PAni) conducting platform has been electrochemically developed for the sensitive sensing of ammonia. The nano PAni films are formed through the assembly of nano granules of the polymer. The average height of the film is in the range of 50 nm. The electrical conductivity of the Si–PAni is influenced in the presence of ammonia. The response of this conductometric sensor is almost linear within 5–50 ppm of ammonia. The response and the recovery times are observed to be 10 and 60 s, respectively for 10 ppm of ammonia. The response time of the sensor for other concentrations (viz. 20, 30, 40, 50 and 60 ppm ammonia) is also in the range of 10 ± 2 s. However, the recovery of the sensor takes slightly longer time (70 ± 3 s) in case of higher concentrations (≥40 ppm) of ammonia
Moving target detection in thermal infrared imagery using spatiotemporal information
No full textAn efficient target detection algorithm for detecting moving targets in infrared imagery using spatiotemporal information is presented. The output of the spatial processing serves as input to the temporal stage in a layered manner. The spatial information is obtained using joint space–spatial-frequency distribution and Rényi entropy. Temporal information is incorporated using background subtraction. By utilizing both spatial and temporal information, it is observed that the proposed method can achieve both high detection and a low false-alarm rate. The method is validated with experimentally generated data consisting of a variety of moving targets. Experimental results demonstrate a high value of F-measure for the proposed algorithm
Thermal stability and electrical characteristics of poly(2-ethyleaniline)-Au nanocomposite
No full textThe Present work reports the synthesis of poly2-ethyleaniline (PEANI) by oxidative polymerization of 2-ethyleaniline and its composite with gold nanoparticles (AuNPs) via in situ chemical synthesis route (simultaneous polymerization and precipitation). PEANI and its nanocomposite were characterized by thermogravimetric analysis-differential Scanning Calorimetry, X-ray diffraction and Fourier transform-infrared. The structural confirmation of the polymer was confirmed by FT-IR which shows strong absorption starting at ~1,600 cm−1 and extended to near-IR, Attributed to the presence of free carrier in the polymer. XRD of Polymer shows large X-rays peaks indicating that the material is rather amorphous with a certain degree of crystallinity where as XRD of PEANI-Au nanocomposite confirms the incorporation of AuNPs in composite. The TEM image showed the formation of PEANI-AuNPs core shell nanostructure. From TGA–DSC studies it was confirmed that the decomposition of the polymer in the composite is lowered by 254 °C as compare to PEANI alone, resulting in weak structure. Whereas I–V characteristics’ shows that the composite has about 10 % lower conductance values than the polymer alone
A low loss mechanical splice for gas sensing using Hollow-Core Photonic Crystal Fibre
No full textIn this paper, a low loss mechanical splice for Hollow-Core Photonic Crystal Fibre (HC-PCF) based multi-gas sensing system is introduced. Compared with the recent micro-structured optical fibre gas cells, the proposed HC-PCF gas cell has relatively simpler construction. The gas cell is composed of HC-PCF of 50 cm length and core diameter is 10 ± 1 μm. The HC-PCF is connected to the single mode fibre (SMF) and multi mode fibre (MMF) via FC-APC connector. This creates a longitudinal gap between the two fibres which acts as a channel of gas diffusion in HC-PCF. The hollow-core and the capillaries in the cladding of HC-PCF act as gas channels. A measurement system for low gas concentrations based on this approach is also propose
Enhancement in sensitivity of fluorescence based assay for organophosphates detection by silica coated silver nanoparticles using organophosphate hydrolase
No full textThe aim of the present work is to enhance the sensitivity of the fluorescence based developed detection assay for the estimation of organophosphates by exploiting the spectral property of metal enhanced fluorescence shown by silver nanoparticles. The receptor entity consisted of organophosphorus hydrolase with a histidine tail (OPH6His) at its C terminus which has been conjugated to pH sensitive high quantum yield fluorophore i-e pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt). The introduction of silica nanoshell (∼30 nm) on silver nanoparticles (∼35 nm) ameliorated tuning of surface plasmon resonance wavelength of silver nanoparticles to the excitation wavelength of pyranine which ultimately led to a ten-fold increase in the fluorescence signal to that given by OPH6His–pyranine bioconjugate. This fluorescence enhancement resulted in lowering of detection limit from 20 ppb to 2 ppb for paraoxon and 50 ppb to 10 ppb for methyl parathion
Shock absorption ability of laminate mouth guards in two different malocclusions using fiber Bragg grating (FBG) sensor
No full textPurpose
The majority of orofacial injuries affect the upper jaw, with the maxillary incisors being most prone to injury, often accounting for as many as 80% of all cases. Children with malocclusion in the anterior segment of the maxilla are more prone to traumatic injuries than those exhibiting normal occlusion, because most often the damaging force impacts directly against the maxillary anterior teeth. Hence, because of the difference of dissipation of the impact force because of the presence or absence of malocclusion, the mouthguard's shock absorption capacity would be influenced by certain factors. In the present study, a unique in vitro experiment utilizing fiber Bragg Grating (FBG) as distributed strain sensors was carried out to evaluate the shock absorption ability of laminate customized mouthguards in two different malocclusions compared with normal occlusion.
Material and methods
The impact was produced using a customized pendulum device with three interchangeable impact objects on typhodont models with two different malocclusions and normal occlusion from different heights. Response of gratings was monitored using an optical spectrum analyzer. Strain induced because each impact was determined from the Bragg's wavelength shifts for each grating. For every model, 12 impact strikes were measured using three different impact objects on the two specified sites by releasing the object from two different heights.
Results and conclusions
The laminated mouthguards showed significant variation in shock absorption ability when different malocclusions were compared. Hence, modifications in the original design of the laminated mouthguards should be considered for athletic competitors with malocclusion to provide adequate protection against impact. FBG sensor has shown the unique advantage of high sensitivity to strain measurement and can be used in further studies. The height of the impact is an important variable in determining the shock absorption ability of mouthguards
Effect of surfactant concentration, solvents and particle size on Pi-A isotherm of silica nanoparticles
No full textWe present here, the effect of surfactant concentration, different solvents and particle sizes on isotherm of silica nanoparticles at air/water interface. The experiments were performed by Langmuir–Blodgett (LB) technique and pressure ∏–A isotherms were recorded. Silica nanoparticles (NPs) of different sizes namely; 30 nm, 150 nm and 630 nm, were synthesized by Stöber's method and characterized by using scanning electron microscopy to determine their sizes and dispersity. As-synthesized NPs were hydrophobized to varying extents through addition of varying amounts, ranging from 0.5 mg to 1.5 mg, of the cationic surfactant,cetyltrimethylammoniumbromide (CTAB). Effect on lift off area (area/particle) and corresponding yield were investigated and reported. This parametric study can
adds on in meeting the requirement of reproducibility of LB films
Luminescent behavior of cadmium sulfide quantum dots for gallic acid estimation
No full textThioglycolic acid capped cadmium sulfide (CdS/T) quantum dots have been synthesized using wet chemistry and their optical behavior has been investigated using UV–visible absorption and fluorescence spectroscopy. The role of the capping agent, sulfide source concentration, pH and temperature has been studied and discussed. Studies showed that alkaline pH leads to a decrease in the size of quantum dots and reflux temperature above 70 °C resulted in red-shift of emission spectra which is due to narrowing of the bandgap. Further, to reduce the toxicity and photochemical instability of quantum dots, the quantum dots have been functionalized with polyethylene glycol (PEG), which resulted in a 20% enhancement of the fluorescence intensity. The application potential of CdS/T-PEG quantum dots was further studied using gallic acid as a model compound. The sensing is based on fluorescence quenching of quantum dots in the presence of gallic acid, and this study showed linearity in the range from 1.3 × 10−8 to 46.5 × 10−8 mM, with a detection limit of 3.6 × 10−8 mM
Formation of circular fringes by interference of two boundary diffraction waves using holography
No full textThe theory of boundary diffraction waves (BDWs) is gaining importance due to its simplicity and physically appealing nature. The present work reports formation of circular fringes far away from the geometrically illuminated region by interference of two BDWs. One BDW is reconstructed from the hologram while the second is coming directly from the knife-edge. The uniqueness of the fringes is that their position can be controlled on the screen at will and fringes can be produced with bright as well as dark central fringe. These results could play an important role in understanding the nature of diffraction of light