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Design and development of instrumentation for landslide monitoring and issue
Get PDFCSIO, Chandigarh has designed and developed an instrument network around standard geo-technical and geo-physical sensors and advanced associated electronics. Network was installed in 2006 for continuous instrumental monitoring of the site at Mansa Devi near Haridwar. The paper highlights design approach for network and explains technical details of different sub modules. Network performance in terms of functional reliability, data generation capability and failure rate in the field has been evaluated and necessary design modifications have been incorporated
Interference and diffraction effects in folding mirror schlieren diffraction interferometer
No full textExperimental investigations on interference and diffraction phenomenon occurring in a folding mirror schlieren diffraction interferometer have been presented. It is shown that the well-known Lloyd mirror interferometer can easily be converted into a folding mirror schlieren diffraction interferometer. Various intermediate stages occur as the basic two-beam interference pattern in Lloyd mirror interferometer is transformed into a schlieren diffraction pattern. Study of these intermediate stages gives a good insight in understanding the transition behaviour between the fundamental phenomenon of interference and diffraction taking place as the mirror-edge approaches the Airy disk
Optical absorption spectrum of single-walled carbon nanotubes dispersed in sodium cholate and sodium dodecyl sulfate
No full textCommercially procured single-walled carbon nanotubes were dispersed in 2 wt% solution of sodium cholate and also in 1 wt% solution of sodium dodecyl sulfate. The absorption spectrum of the suspensions was studied in ultraviolet–visible–near-infrared (UV–vis–NIR) range. Two distinct bands, each containing three peaks, were observed in NIR range for both the suspensions. These peaks correspond to transitions between van Hove singularities E11 and E22 in the density of states of the semiconducting nanotubes. Comparing positions of the observed peaks with the empirical Kataura plot, the diameters and chiralities of the nanotubes were estimated. Using tight binding approximations, the diameter of the nanotubes was also estimated theoretically. Discrepancies between the theoretically calculated diameters and those obtained by empirical Kataura plots are found to be higher for E11 peaks. It has been suggested that the reason for this discrepancy is that the observed E11 peaks are blue-shifted due to Coulomb interactions and exciton formation
Covalent attachment of actin filaments to Tween 80 coated polystyrene beads for cargo transportation
No full textIn this manuscript, a new strategy has been reported for circumscribed covalent attachment of barbed and pointed ends of actin filaments to polystyrene beads. A comparative study of attachment of actin filaments to polystyrene beads was performed by blocking functionally active sites on polystyrene beads with nonionic detergents such as Tween 20, Tween 80 and polyethylene glycol (PEG). Effective blocking of active sites was obtained with Tween 80 at 0.1% concentration. Attachment of single bundle of actin filament to bead was assessed by rotational motion of bead tailed actin in front and lateral view. Velocity of actin filaments attached to different size of beads in in-vitro motility assay was calculated to ascertain their attachments. Velocity of actin attached to 1.0 and 3.0 microm polystyrene beads was reduced to 3.0-4.0 and 0.0-1.0 microm/s, respectively as compared to free actin velocity of 4.0-6.0 microm/s. Single point attachment of actin filaments to different size of beads was assessed by decrease in sliding velocity. Present study provides insight into the actin-myosin based molecular motor systems for drug delivery and biosensors applications
Micellar behavior of aqueous solutions of dodecyldimethylethylammonium bromide, dodecyltrimethylammonium chloride and tetradecyltrimethylammonium chloride in the presence of α-, β-, HPβ-and γ-cyclodextrins
No full textConductivity, static fluorescence and 1 H NMR measurements have been carried out to study the micellar behavior of aqueous solutions of dodecyldimethylethylammonium bromide (DDAB), dodecyltrimethylammonium chloride (DTAC) and tetradecyltrimethylammonium chloride (TDAC) in absence and presence of α -cyclodextrin ( α -CD), β -cyclodextrin ( β -CD), hydroxypropyl- β -cyclodextrin (HP β -CD) and γ -cyclodextrin ( γ -CD). The conductivity measurements were carried out at 298.15 K. The influence of cyclodextrins on the micellar parameters, such as cmc * (apparent critical micellar concentration), β (degree of ionization) have been analyzed. Thermodynamics of the systems was discussed in terms of the change in standard free energy of micellization, . Micellization was found to be less spontaneous in presence of cyclodextrins. The fluorescence intensity of the surfactant solutions is enhanced by the addition of cyclodextrins. The association constants obtained from conductivity and fluorescence data suggest the binding of γ -CD with the surfactants to be strongest among all the cyclodextrins used. 1 H NMR chemical shift changes provide powerful means for probing the cyclodextrin–micellar interactions and inclusion of surfactant is shown by the change in the chemical shift of some of the guest and host protons in comparison with the chemical shifts of the same protons in the free compounds
Comparative Study of Different Schlieren Diffracting Elements
No full textThis paper presents an analysis of diffraction effects taking place at different Schlieren diffracting elements. Two types of diffraction effects are prominent in the Schlieren schemes. One is diffraction of direct light (source image) at the Schlieren element, which limits the sensitivity and resolution of Schlieren systems. The second type is the diffraction of light deflected from the test object at the Schlieren-diffracting element. This second type of diffraction degrades the quality of Schlieren results. Experimental results showing the effect of diffraction of light deflected from the test object at a phase knife-edge, corner of a square phase aperture and an optical fiber tip as Schlieren diffracting elements have been presented and discussed
Dual beam encoded extended fractional Fourier transform security hologram with in-built repositioning
No full textThis paper describes a simple method for making dual beam encoded ex-tended fractional Fourier transform (EFRT) security holograms. The hologram possesses different stages of encoding so that security features are concealed and remain invisible to the counterfeiter. These concealed and encoded anticounterfeit security features in the security hologram can only be read through a key hologram. Key hologram also facilitates in-built repositioning of security hologram. The method of fabrication, the principle of reconstruction and the experimental results are presented
Laser Based Projectile Speed Measurement System
No full textThe design and construction of a system to accurately determine the speed of a projectile (bullet) by measuring the time of flight between two parallel laser screens is described. Each screen is formed by a laser source and a set of prisms. At the detection end of each of the screens, a collector lens focuses the incident laser light beam onto a photodetector. The collector lens and detector are kept in a recess so that no stray or ambient light falls on the photodetector. Whenever a projectile crosses either of the screens, the corresponding photodetector senses the event, due to partial or full obscuration of the incident energy. An electronic circuit is used to accurately record the time when the projectile crosses each screen, and the time interval gives the time of flight. The distance between the screens being known, the velocity is displayed on a computer screen. Because a single collimated beam of light generates the entire optical curtain, the reduction in incident energy at the photodetector plane is independent of the entry point of the projectile into the screen. Due to the baffling of the photodetector from ambient light, the optical screens can be used at indoor or outdoor ranges equally effectively
Interferometric key readable security holograms with secrete-codes
No full textA new method is described to create secrete-codes in the security holograms for enhancing their anti-counterfeiting characteristics. To imitate these codes is di±cult as pure phase objects having complex phase distribution function are used to modulate the object beam that is recorded in conjunction with an encoded interferometric reference beam derived from a key hologram. Lloyd's folding mirror interferometer is used to convert phase variations of the reconstructed wave-front into an intensity pattern for hologram authenticity veri¯cation. Creating the secrete-codes through an interferometric reference beam from the key hologram facilitates a multi-stage authenticity veri¯cation as well as easy repositioning of the security hologram through a speci¯c Moir¶e pattern generated during the veri¯cation proces
Analysis of Rotary Electrical Discharge Machining Characteristics in Reversal Magnetic Field for Copper-En8 Steel System
No full textThe material removal rate (MRR), along with the
electrode wear rate (EWR), plays an important role in
analysing machine output during electrical discharge
machining. This work focuses on the improvement of
machine output by introducing an induced magnetic field
on the workpiece during rotary electrical discharge machining (REDM) of EN-8 steel with a rotary copper
electrode. The workpiece was placed inside the induced
magnetic field, wherein polarity of the magnetic field gets
reversed periodically. Using Taguchi’s recommended design
of experiments, we initially conducted experiments
with eight input parameters at different levels . Significant
parameters were identified with the help of the signal-tonoise
ratio and ANOVA. Finally, another set of experiments
was conducted for analysis of the process and development
of empirical expressions for MRR and EWR. Experimental
results established that rotary electrical discharge machining with a polarity reversal magnetic field delivers better machining output than machining in a non-magnetic field.Thus, this work benefits the EDM process by reducing the machining costs and by producing better geometrical
trueness on workpieces, as MRR increased and EWR
decreased