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Optical fiber nanoprobe preparation for near-field optical microscopy by chemical etching under surface tension and capillary action
No full textWe propose a technique of chemical etching for fabrication of near perfect optical fiber nanoprobe (NNP). It uses photosensitive single mode optical fiber to etch in hydro fluoric (HF) acid solution. The difference in etching rate for cladding and photosensitive core in HF acid solution creates capillary ring along core-cladding boundary under a given condition. The capillary ring is filled with acid solution due to surface tension and capillary action. Finally it creates near perfect symmetric tip at the apex of the fiber as the height of the acid level in capillary ring decreases while width of the ring increases with continuous etching. Typical tip features are short taper length (~4 µm), large cone angle (~38°), and small probe tip dimension (<100 nm). A finite difference time domain (FDTD) analysis is also presented to compare near field optics of the NNP with conventional nanoprobe (CNP). The probe may be ideal for near field optical imaging and sensor applications
EMG Signal Analysis for Identifying Walking Patterns of Normal Healthy Individuals
Get PDFSurface electromyography is the technique for measuring levels of muscle activity. When a
muscle contracts, electrical activity generated as action potentials propagate along the muscle
fibers. There are two types of Surface EMG (SEMG)-Static scanning SEMG and Dynamic
SEMG. In Dynamic SEMG, electrodes are attached to the skin and muscle activity is measured
and graphed as the patient moves through various ranges of motion. The authors in this paper
discuss the use of EMG for analyzing different phases of walk by acquiring the surface EMG
from Gastrocnemius and Soleus muscles of the leg .with the subjects walking at two self selected
pace- fast and slow. These surface EMG signals picked up during the muscle activity are
interfaced with a PC system via Biometrics EMG acquisition system. The acquired signals were
processed and analyzed using filtering techniques. The results showed a marked variation in the
RMS amplitude levels and median frequency of EMG as the subject’s walking pace changed
Realization and Installation of Landslides Instrumentation Network at Mansa Devi (Haridwar), Indian Landslides
No full textLandslides and other associated m echanism of erosion have to be accepted as part of the natural proc ess. It has been observed that in rainy season and som etim es even otherwise, part of earth gives away down steep slopes causing landslides and which in turn adversely affects a variety of resources. Therefore to m itigate the losses of property and hum an lives, continuous m onitoring of active landslides and their early prediction with the help of i nstrum entation network is very m uch essential.CSIO, Chandigarh has installed an Instrum ent network at Mansa Devi (Haridwar) landslide for the first tim e in our country. The com plete system is operational round the clock and data is being collected and analy zed regularly. In this paper description of com plete instrum entation network has been explained
Development of emperical model for different process parameters during rotary electrical discharge machining of copper–steel (EN-8) system
No full textThe present work investigates the machining characteristics of EN-8 steel with copper as a tool electrode during rotary electrical discharge machining process. The empirical models for prediction of output parameters have been developed using linear regression analysis by applying logarithmic data transformation of non-linear equation. Three independent input parameters of the model viz. peak current, pulse on time and rotational speed of tool electrode are chosen as variables for evaluating the output parameters such as metal removal rate (MRR), electrode wear ratio (EWR) and surface roughness (SR). Analysis of the results, by using Taguchi's recommended signal–noise ratio formulae and ANOVA, has been conducted to identify the significant parameters and their degree of contribution in the process output. Analyzed results shows that peak current and pulse on time are the most significant and significant parameters for MRR and EWR, respectively. But peak current and electrode rotation become the most significant and significant parameters for SR, respectively. Experimental results further revealed that maximizing the MRR while minimizing EWR and improving the surface roughness, cannot be achieved simultaneously at a particular combination of control parameters setting. In addition, the predictions based on the above developed models have been verified with another set of experiments and are found to be in good agreement with the experimental results
Moiré Pattern Encoded Extended Fractional Fourier Transform Security Hologram
No full textThis paper describes a simple method for making extended fractional Fourier transform (EFRT) based Moiré pattern encoded security holograms. These security holograms contain multifold concealed and encoded anticounterfeit security features that can only be read through a key hologram and periodic patterns in the final reading process. The encoded features in these holograms are concealed and unknown to the counterfeiter. These features are encoded separately for each individual recording in angularly multiplexed extended fractional Fourier transform hologram (EFRTH). The principle of recording and reconstruction of the proposed security hologram along with experimental results are presented
Craniofacial Computerized Tomography Analysis of the midface of patients with repaired complete unilateral cleft lip and palate
No full textIntroduction: Computerized tomography (CT) makes regional anatomy available as a series of cross-sectional axial images that can be analyzed unobstructed by other anatomic features. In this study, we aimed to analyze the maxillary dentoalveolar and deeper structures in patients with surgically repaired complete unilateral cleft lip and palate (CLP) and to investigate whether significant asymmetry existed in the deeper midfacial structures, using axial CT. Methods: Axial CT scans of 15 children (7 boys, 8 girls; mean age, 11.59 ± 1.34 years) with repaired complete unilateral CLP were acquired parallel to Reid's base line. Specific landmarks applicable for CT were defined and plotted to undertake a comprehensive Craniofacial CT Analysis of the midface. Twenty-six pairs of transverse and sagittal measurements made to a cranial base midsagittal construct and interspinosum fit line, respectively, were compared by using the paired t test. Results: Significant reduction of 19.05% in the nasal chamber width (2.54 ± 1.49 mm; P <0.001), more distal position of the bony alar base (2.28 ± 1.71 mm; P <0.001), and the sagittal position of the most prominent anterolateral point on the maxillary alveolar process (1.62 ± 1.85 mm; P <0.01) were noted on the cleft side. The lower half of the bony nasal septum was consistently deviated toward the cleft side, and the nasal tip was deviated to the noncleft side in 60% of the subjects. The anterior nasal spine was deviated to the noncleft side in 73.3% of the subjects and a mean deviation of the anterior nasal spine of 2.84 ± 3.90 mm toward the noncleft side was measured. Significant sagittal and transverse asymmetry in deeper midfacial regions was not observed. Unilateral dental-arch collapse was observed in 73.3% of the sample, bilateral collapse in 20%, and no collapse in 6.7%. The soft-tissue support of the alveolar margins of the cleft did not show significant differences between the cleft and noncleft sides. Conclusions: CT is an excellent method for quantifying surface and deep craniofacial structures. Most asymmetries and deformities in the 10- to 14-year-old patients with repaired complete unilateral CLP we studied were in the dentoalveolar area near the cleft and the nasal chamber and not in the deeper regions of the maxillary complex
Fuel Adulteration Detection using Long Period Fiber Grating Sensor Technology
Get PDFAdulteration of petrol and diesel with kerosene is a common malpractice in India because kerosene has been made easily accessible at a price much cheaper than that of petrol and diesel. Such adulteration results in increased pollution, decrease in engine or machine performance, reduced lifetime of components, lower returns for money of the buyers and decrease in availability of kerosene to the needy people. There is no standard technique that is followed universally for detection of adulteration level. In this study, application potential of long period fiber grating (LPFG) sensor technology to detect fuel adulteration has been investigated. It was possible to detect presence of 10% contaminant in petrol and diesel using LPFG technique whereas the traditional technologies are able to detect presence of about more than 20% of the same
Immobilization of single walled carbon nanotubes on glass surface
No full textThe chemical modification of carbon nanotubes is an emerging area in material science. In the present study we dispersed the carbon nanotubes using optical tweezers and then investigated the covalent immobilization of Single Walled Carbon Nanotubes (SWCNTs) on chemically functionalized glass surface. Carboxylic group was created on SWCNTs and converted into acid chlorides. FT-IR spectra for functionalized SWNTs revealed three additional peaks at 1739.4 cm− 1, 3430.9 cm− 1, and 1642.0 cm− 1 corresponding to carboxyl group, hydroxyl and carbonyl group. Finally these were covalently immobilized on poly-l-lysine coated glass substrate. Atomic Force Microscopic (AFM) analysis confirmed immobilized SWCNTs on glass surface. The covalent immobilization of SWCNTs on glass has an important role in fabrication of carbon nanotubes based electrodes for biosensor and bionanotechnology application
Generation of selenium containing nano-structures by soil bacterium Pseudomonas Aeruginosa
No full textThe aim of the study was to explore the biogenesis of nano-structures through reduction of selenium by soil bacterium Pseudomonas aeruginosa. The strain under study indicated tolerance of selenium upto 50 mg L-1, using reductive mechanisms for detoxication, thus biotransforming selenium oxyanions to elemental red selenium. Partial characterization using AFM of the biotransformed selenium was carried out which indicated formation of spherical amorphous allotropic elemental selenium
Fabrication of low cost integrated micro-capillary electrophoresis analytical chip for chemical analysis
No full textA capillary electrophoresis (CE) micro-analytical chip has been designed and fabricated with integrated electrodes for sample injection, separation and electrochemical detection using standard fabrication technology. The device is ready to use that does not need any extra mechanical apparatus for electrode insertion. Silicon substrate with micro-channels and polycarbonate (PC) cover plate was bonded with CY-TOP (R), which helps to reduce the cost of mu-CE chip. The micro-capillary electrophoresis (mu-CE) chip has been successfully used for testing hydrogen peroxide, ascorbic acid, uric acid simultaneously and glucose. All these oxidizable species could be detected in less than 50s. This microsystem showed a very good reproducibility. (C) 2007 Elsevier B.V. All rights reserved