202 research outputs found
Structural and electrical characterization of tamarind seed polysaccharide (TSP) doped with NH4HCO2
No full text
Enhanced biocompatibility of multi-walled carbon nanotubes by surface modification: Future perspectives for drug delivery system
No full textPolyethyleneglycol/silver functionalized reduced graphene oxide aerogel for environmental application
No full textConformational, vibrational spectroscopic and nonlinear optical activity studies on N,N-Di-Boc-2-amino pyridine : A DFT approach
No full textStructural, vibrational spectroscopic and quantum chemical studies on indole-3-carboxaldehyde
No full textDeceleration of a Supersonic Beam of SrF Molecules
No full textThe work depicted in this thesis demonstrate the successful operation of a 4 meter long traveling-wave Stark decelerator. This is a novel tool for deceleration of heavy diatomic molecules to arbitrarily slow beams with a very small velocity spread which can serve as ideal starting point for precision tests of fundamental physics. The first part of the thesis discusses the characterization of a new Supersonic beam source for creation of SrF molecules which serves as an ideal candidate for precision test of nuclear spin dependent parity violation. The later part of the thesis discusses the the results of deceleration of a SrF molecules in the N = 1 rotation state of the SrF(v = 0) electronic ground state from a supersonic beam with an initial velocity of 340 m/s to 265 m/s using a deceleration potential with 3.25 k V voltage amplitude using a the 4 m long traveling-wave decelerator built in our research lab. Increasing the voltage amplitude of the potential to 4.8 kV, we were able to decelerate molecules from 340 m/s to 250 m/s which corresponds to a deceleration strength of 6.6 km /s2. By cooling the valve by flushing cold nitrogen gas through the valve enclosure we were able to decrease the initial velocity of the supersonic beam. With the valve cooled to ~190 K, we demonstrated deceleration of SrF molecules from 290 m/s to 120 m/s which corresponds to the removal of almost 85% of the initial kinetic energy. The thesis described the operation of the decelerator and end with an outlook for precision tests using this novel tool
AUTOMATIC IDENTIFICATION OF USER INTEREST FROM SOCIAL MEDIA
No full textAutomatic identification of user interest from social media has gained much attention in the recent years. In Twitter, users could post tweets about a wide range of topics. These tweets could be analyzed to identify the user’s interests, which could be used to personalize recommendations for that user. But the short length of these tweets poses a huge challenge in classifying the tweets using traditional classification algorithms. In this thesis, a hybrid approach has been proposed to overcome this challenge. All tweets containing URLs are grouped as sessions with session duration as 1 hour, which increases the text length considerably. These sessions are then classified into 8 pre-defined categories using logistic regression. Based on the categories which appeared frequently in these sessions, top 3 categories are identified as the interests of the user. Experiments show that the proposed approach is able to identify the user interest in a precise manner
Deceleration of a Supersonic Beam of SrF Molecules to 120 m s(-1)
No full textA beam of SrF molecules is decelerated from 290 to 120 m s(-1) . Following supersonic expansion, the molecules in the X(2) Σ (ν=0, N=1) low-field-seeking state are trapped by the moving potential wells of a traveling-wave Stark decelerator. With a deceleration strength of 9.6 km s(-2) the removal of 85 % of the initial kinetic energy in a 4 m-long modular decelerator is demonstrated. The absolute amount of kinetic energy removed is a factor of 1.5 higher compared to previous Stark-deceleration experiments. The demonstrated decelerator provides a novel tool for the creation of highly collimated and slow beams of heavy diatomic molecules, which serve as a good starting point for high-precision tests of fundamental physics
Patterns of emergence, import of egg energy and energy export via emerging dragonfly populations in a tropical pond
No full textThe most abundant dragonflies Brachythemis contaminata, Orthetrum sabina, Diplacodes trivialis, Pantala flavescens and Trithemis festiva in the tropical pond Idumban emerged from November to April during the years 1973,1974 and 1975. The date of initiation of emergence of all the species was synchronized and tied to the events following the north west monsoon in November. During the seasons '73-74 and '74-75, as many as 10,693 and 7,910 adults emerged; females outnumbered the males in all the 5 species; male populations of B. contaminata, O. sabina, D. trivialis, P. flavescens and T. festiva represented 47, 48, 46, 49 and 44% during the '73-74 season, 48, 48, 46, 46 and 49% during the '74-75 season, respectively. The adult dragonflies equivalent to 2,442 Kcal emerged from the Pond during the season '73'-74. Of this, B. contaminata contributed 30%, D. trivialis 7%, O. sabina 12%, P. flavescens 23% and T. festiva 28%. For the season '74-75, the dragonflies equivalent to 1,602 Kcal emerged from the Pond and the contribution was in the following order: B. contaminata: 31%, O. sabina: 8%, D. trivialis: 13%, P. flavescens: 27% and T. festiva: 21%. Import of energy due to inoculation of B. contaminata eggs into the Pond Idumban was 73 Kcal/ year and the output from the Pond via emerging B. contaminata population alone amounted to 620 Kcal/ year; the net energy loss from the Pond was 548 Kcal/ year. During either season, as much as 99.7% of B. contaminata eggs failed to attain adulthood due to infertility (5.8%), unhatchability (12%) and predation during the egg and nymphal stages (82.5%). During the study, the GPP of the Pond was 26,073 Kcal/m2/ year, and output of energy through emergence of 5 dragonfly species amounted to 0.0045 Kcal/m2/year, i.e. 0.00002% of the GPP is lost through the emerging carnivorous odonates; comparable values available for the emerging detritivorous chironomids, herbivorous dipterans and mayflies fall between 1.0 and 0.1%
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