Digitized archive of the Kodaikanal images: Representative results of solar cycle variation from sunspot area determination

Photographic images are valuable data resources for studying long term changes in the solar magnetic field and its influence on the Earth's climate and weather. We digitized more than 100 years of white light images stored in photographic plates and films that are available at Kodaikanal observatory starting from 1904. The digitized images were calibrated for relative plate density and aligned in such a way that the solar north is in upward direction. A semi-automated sunspot detection technique was used to identify the sunspots on the digitized images. In addition to describing the calibration procedure and availability of the data, we here present preliminary results on the sunspot area measurements and their variation with time. The results show that the white-light images have a uniform spatial resolution throughout the 90 years of observations. However, the contrast of the images decreases from 1968 onwards. The images are circular and do not show any major geometrical distortions. The measured monthly averaged sunspot areas closely match the Greenwich sunspot area over the four solar cycles studied here. The yearly averaged sunspot area shows a high degree of correlation with the Greenwich sunspot area. Though the monthly averaged sunspot number shows a good correlation with the monthly averaged sunspot areas, there is a slight anti-correlation between the two during solar maximum The Kodaikanal data archive is hosted at http://kso.iiap.res.in. The long time sequence of the Kodaikanal white light images provides a consistent data set for sunspot areas and other proxies. Many studies can be performed using Kodaikanal data alone without requiring intercalibration between different data sources.Comment: 9 pages, A&A(accepted

A study of microstructural characteristics of Ni-based superalloys at high temperatures

The microstructural characteristics of the Ni-based superalloy MAR-M245(Hf) which is used in manufacturing the components of the Space Shuttle main engine are studied. These superalloys need optimum heat treatment to get the best results. To find out the optimum heat treatment, the techniques of differential thermal analysis (DTA) and the optical photomicrographs were utilized. In the first phase, the existing experimental equipment like cutting, grinding/polishing machines and metallurgical microscope were set up to cut/polish and take the photomicrographs. In the beginning of the project a Perkin Elmer differential thermal analyzer DTA1700 along with a temperature programmed and the needed computer interface was procured and made operational. In the second year a Leitz Metallux-3 hot state research microscope was also procured and installed for in-situ observation of the superalloy samples. The hot stage when tested for the first time alloyed the thermocouple with the Tantalum heating element and has now been installed. Samples of MAR-M246(Hf), MAR-M247, Waspaloy, Udimet-41, CMSX-3, and CMSX-3 (Polycrystalline and single crystals) were studied using a differential thermal analyzer and the results are reported. Photomicrographs of the Ni-based superalloy MAR-M246 (Hf) were recorded before and after heat treatment at certain temperatures. More heat treatments need to be done before a final inference can be reached

EVALUATION OF LEUCAS ASPERA WHOLE PLANT EXTRACTS FOR DIURETIC AND LAXATIVE PROPERTY

ABSTRACTObjective: This study was undertaken to investigate diuretic and laxative potency of Leucas aspera whole plant.Methods: The dried whole plant (leaves, stems, and flowers) material was subjected to extraction by continuous hot percolation method. Inevaluation of diuretic activity male albino rats were used as the experimental animals. The first group of animals, serving as control, received normalsaline (25 ml/kg, post-operative); the second group received furosemide (10 mg/kg, post-operative) in saline. Other groups received doses of extract(200-400 mg/kg) in normal saline. The parameters determined were total urine volume, the concentration of Na(chloride) in the urine. Na+ and K+ concentrations were determined by flame photometer, and Cl−+(sodium), K concentration was estimated by titrimetric method.Laxative activity was also studied using male albino rats. The animal groups were administered orally either with vehicle (1% Tween-80 solution innormal saline, 25 ml/kg), reference standard drug, agar-agar (300 mg/kg, post-operative) in saline or doses of extract (200-400 mg/kg). After 8 h ofdrug treatment, the feces were collected and weighed.Results: This study revealed that L. aspera whole plant extracts possesses significant diuretic and laxative activity in comparison with the standarddrugs. The activity may be due to the chemical constituent present in the plant parts. The further studies may be taken up to isolate these activeconstituents.Conclusion: L. aspera whole plant possesses diuretic and laxative property since it contains a variety of phytoconstituents.Keywords: Leucas aspera, Diuretics activity, Lipchitz method, Laxative activity, Furosemide, Agar-agar.+(potassium), and Clâˆ

The propensity of molecules to spatially align in intense light fields

The propensity of molecules to spatially align along the polarization vector of intense, pulsed light fields is related to readily-accessible parameters (molecular polarizabilities, moment of inertia, peak intensity of the light and its pulse duration). Predictions can now be made of which molecules can be spatially aligned, and under what circumstances, upon irradiation by intense light. Accounting for both enhanced ionization and hyperpolarizability, it is shown that {\it all} molecules can be aligned, even those with the smallest static polarizability, when subjected to the shortest available laser pulses (of sufficient intensity).Comment: 8 pages, 4 figures, to be submitted to PR

Center to limb observations and modeling of the Ca I 4227 A line

The observed center-to-limb variation (CLV) of the scattering polarization in different lines of the Second Solar Spectrum can be used to constrain the height variation of various atmospheric parameters, in particular the magnetic fields via the Hanle effect. Here we attempt to model non-magnetic CLV observations of the $Q/I$ profiles of the Ca I 4227 A line recorded with the ZIMPOL-3 at IRSOL. For modeling, we use the polarized radiative transfer with partial frequency redistribution with a number of realistic 1-D model atmospheres. We find that all the standard FAL model atmospheres, used by us, fail to simultaneously fit the observed ($I$, $Q/I$) at all the limb distances ($\mu$). However, an attempt is made to find a single model which can provide a fit at least to the CLV of the observed $Q/I$ instead of a simultaneous fit to the ($I$, $Q/I$) at all $\mu$. To this end we construct a new 1-D model by combining two of the standard models after modifying their temperature structures in the appropriate height ranges. This new combined model closely reproduces the observed $Q/I$ at all the $\mu$, but fails to reproduce the observed rest intensity at different $\mu$. Hence we find that no single 1-D model atmosphere succeeds in providing a good representation of the real Sun. This failure of 1-D models does not however cause an impediment to the magnetic field diagnostic potential of the Ca I 4227 A line. To demonstrate this we deduce the field strength at various $\mu$ positions without invoking the use of radiative transfer.Comment: 20 pages, 10 figures, Accepted for publication in Ap

Isomerization of alpha-pinene oxide over solid acid catalysts

Master'sMASTER OF SCIENC

Seasonal abundance and host plants of coconut stick insect (Graeffea crouanii Le Guillou) in coconut plantations of Fiji islands

Field survey conducted in major coconut growing regions in the three Fiji islands viz., Viti Levu, Vanua Levu, and Taveuni, revealed the presence of only one pest species of stick insect, Graeffea crouanii. Temperature had a significant effect on the level of infestation in the farms surveyed, while the effect of rainfall and humidity on the infestation was insignificant. Severe infestation was observed in isolated pockets, and the pest distribution was discontinuous in the surveyed areas. On a damage scale index, the insect infestation on coconut palms ranged from 0 to 4 grades. The peak increase of G. crouanii populations was from November to April in wet season at each of the three hotspots: Namaumada (Viti Levu), Dawara (Vanua Levu), and Salialevu (Taveuni). The occurrence of G. crouanii at varying damage levels in the present study may be attributed to the presence of sparse coconut palms in isolated coconut plantations. The field survey identified many alternate host plants of G. crouanii in the two plant families viz., Arecaceae and Pandanaceae. The information on the seasonal abundance and infestation levels of G. crouanii and its alternate host plants are discussed in formulating location-specific pest management strategies

Ammonia Gas Sensing Characteristics of Spin Coated Polyaniline Films

The conductive layer of emeraldine base polyaniline (PANI) thin film coated on silicon has successfully tested for ammonia. The bulk PANI powder was synthesized by oxidative polymerization of aniline using ammonium peroxidisulfate in an acidic medium and dissolved in N-methyl pyrrolidone (NMP) for coating the thin film on Silicon using spin coater. FTIR, UVvisible, and SEM were used to characterize the PANI thin film. The electrical conductivity of the PANI films has been studied by measuring the change in electrical conductivity by Four Probe Set up on exposure to ammonia gas (NH3) at different concentrations from 100 ppm to 500 ppm. margin

Investigation of the Influence of Microgravity on Transport Mechanisms in a Virtual Spaceflight Chamber: A Ground Based Program

In January 1992, the IML-1 FES experiment produced a set of classic experimental data and a 40 hour holographic "movie" of an ensemble of spheres in a fluid in microgravity. Because the data are in the form of holograms, we can study the three-dimensional distribution of particles with unprecedented detail by a variety of methods and for a wide variety of interests. The possession of the holographic movie is tantamount to having a complex experiment in space while working in an easily accessible laboratory on earth. The movie contains a vast amount of useful data, including residual g, g-jitter, convection and transport data, and particle fluid interaction data. The information content in the movie is so great that we have scarcely begun to tap into the data that is actually available in the more than 1000 holograms, each containing as much as 1000 megabytes of information. This ground-based project is exploiting this data and the concept of holographic storage of spaceflight data to provide an understanding of the effects of microgravity in materials processing. This paper provides the foundation, objectives, and status of the ground based project. The primary objective of this project is to advance the understanding of microgravity effects on crystal growth, convection in materials processing in the space environment, and complex transport phenomena at low Reynolds numbers. This objective is being achieved both experimentally and theoretically. Experiments are making use of existing holographic data recorded during the IML- I spaceflight. A parallel theoretical effort is providing the models for understanding the particle fields and their physics in the microgravity environment

DETERMINING THE SOURCE OF CORONAL HELICITY THROUGH MEASUREMENTS OF BRAIDING AND SPIN HELICITY FLUXES IN ACTIVE REGIONS

ABSTRACT Magnetic helicity has become a valuable tool for understanding the energetics and dynamics of coronal magnetic fields. Recently, long time sequences of magnetograms have been used to measure the flux of helicity into active region coronae. We demonstrate how this helicity flux can be usefully decomposed into contributions of differing origin, called ''spin'' helicity and ''braiding'' helicity. These contributions could be envisioned to come at the expense of twist and writhe helicity, respectively, of a subphotospheric flux tube anchored to the regions. In order to effect this decomposition, each magnetogram is partitioned into a set of unipolar regions. We present a method of defining such regions so that they persist through the sequences and track the photospheric flow. The spin helicity of a given region quantifies the mean rotation rate of motions internal to that region, while braiding helicity is injected by the motions of whole regions about one another. Applying the method to six active regions shows cases where either spin or braiding dominates, and where they have the same signs and opposite signs. Thus, it would seem that no general statement can be made regarding the dominance of twist or writhe in supplying helicity to the corona. In one particular case, spin and braiding helicity follow different time histories but inject equal and opposite net helicities. This suggests that the spinning and braiding are driven by a kink instability in the submerged flux tube. Subject headingg s: MHD -Sun: magnetic field