Analysis of solar radiation pressure induced coupled liberations of a gravity stabilized axisymmetric satellite

A planar, fixed-orbit model of the rotation of the planet Mercury is analyzed. The model includes only the solar torques on the planet's permanent asymmetry and its solar tidal bulge. For this model, it is shown that the zero of the averaged tidal torque corresponds to an asymptotically stable periodic solution of the second kind which, for two tidal torque representations, is close to the asymptotically stable equilibrium point corresponding to an exact 32 spin-orbit resonance. A conjecture that the current rotation state of Mercury is due to transfer from capture by the zero of the averaged tidal torque to 32 resonance capture with changes in the eccentricity of the planet's orbit is discussed briefly.     

Ionic characters of lake water of Bharti promontory,Larsemann Hills,East Antarctica

The Larsemann Hills area represents a unique environmental setting between marine and glacial ecosystems. One of the promontories of this region, named Bharti, depicting similar set up was selected for the study of chemical parameters with special reference to its ionic characters. Water samples from 6 selected lakes of Bharti promontory, Larsemann Hills area were collected during the austral summer of 2004–05 and analysed for major ionic concentration and Total Dissolved Solid (TDS). This study is aimed at understanding the water chemistry of lakes of this island with emphasis on correlation between different ionic concentrations, TDS and its possible causes. The study will provide baseline data that will be useful for planning further studies. Analytical result shows that the water chemistry of these lakes is mainly governed by the lithology, precipitation, drainage and marine environment. Minor contribution of evaporation, has also been observed on the chemistry of one of the lake water. The main source of water for these lakes comes mainly from snow precipitation and its melting. The drainage line mostly goes towards eastern direction for these lakes.     

Trace elemental and Nd-Sr-Pb isotopic compositional variation in 37 lava flows of the Mandla lobe and their chemical relation to the western Deccan stratigraphic succession,India

The Mandla lobe is a 900 m thick lava pile that forms a 29,400 km² northeastern extension of the Deccan Traps. Earlier, combined field, petrographic, and major element studies have shown that this lobe comprises 37 lava flows. Using a combination of trace elements (Ba, Ti, Zr, Rb, Sr) and Nb/Zr values, we group the flows into six chemical types (A–F) that are separated stratigraphically. Combined trace element and Nd-Pb-Sr isotopic data, document the presence of lavas resembling those of the Poladpur Formation and less abundantly, the Ambenali Formation of the southwestern Deccan are in conformity with the earlier reconnaissance work. In addition, our data reveal several flows similar to those of the Mahabaleshwar Formation, the type sections of which are located?~?900 km to the southwest. Based on the isotopic data the superposition of Mahabaleshwar-like flows over flows with Ambenali- and Poladpur-like characteristics is in the same stratigraphic order seen in the southwestern Deccan type section. However, from the stratigraphy indicated by the Discriminant Function Analysis (DFA) results and the serious discrepancy between the DFA and isotopic data, it seems that few Mandla lobe flows are different and not in the same stratigraphic order as in the southwestern part of the province. To some extent the differences may be explained by faulting along four large post-Deccan normal faults near Nagapahar, Kundam, Deori, and Dindori areas across which offsets of ~150 m have been measured. This post-emplacement faulting accounts for the presence of several chemically Mahabaleshwar-like lavas at the base of the ~900 m thick Mandla lobe pile, at a lower elevation than a thick sequence dominated by chemically Poladpur-like flows. However, presence of common signature lavas (similar to that in the northeastern Deccan) cannot be ruled out in this area. They are similar to Poladpur-type lavas both chemically and isotopically. They appear in different formations and erupted at different times other than Poladpur Formation. Close similarities in petrogenetic processes between the two regions are indicated, although it is not clear whether any of the Mandla lobe lavas are far-traveled counterparts of flows cropping out in the southwestern Deccan, or whether some magma migrated laterally in dike systems over great distances. Feeder dykes have not been found in the study area except for Chakhla-Delakhari Intrusive Complex (CDIC) in Satpura region that shows major and trace elemental similarities with the Seoni lavas, although, long distance transport of magma is yet to be proved. The Poladpur-like Mandla lobe flows appear to be different flows from those of the Poldapur Formation in the southwest, as they are somewhat different in isotopic (higher ²⁰⁶Pb/²⁰⁴Pb) composition. They also differ from any known flows in the other southwestern formations, but are broadly similar to flows found in sections across the northern Deccan west of the Mandla lobe.     

Feeder and post Deccan Trap dyke activities in the northern slope of the Satpura Mountain: Evidence from new 40Ar-39Ar ages

We present new 40Ar-39 Ar plagioclase crystallization ages from the dykes exposed at the northern slope of the Satpura Mountain range near Betul-Jabalpur-Pachmarhi area,~800 km NE of the Western Ghats escarpment.Among the two plateau ages,the first age of 66.56±0.42 Ma from a dyke near Mohpani village represents its crystallization age which is either slightly older or contemporaneous with the nearby Mandla lava flows(63-65 Ma).We suggest that the Mohpani dyke might be one of the feeders for the surrounding lava flows as these lavas are significantly younger than the majority of the main Deccan lavas of the Western Ghats(66.38-65.54 Ma).The second age of 56.95±1.08 Ma comes from a younger dyke near Olini village which cuts across the lava flows of the area.The age correlates well with the Mandla lavas which are chemically similar to the uppermost Poladpur,Ambenali and Mahabaleshwar Formation lavas of SW Deccan.Our study shows that the dyke activities occurred in two phases,with the second one representing the terminal stage.     

Trace elemental signatures and mineral chemistry of clays associated with the alteration halos of the Paleoproterozoic U mineralization in Bijawars of the Sonrai Basin,Central India

Acta Geochimica - Paleoproterozoic Bijawars of the Sonrai basin consists of (a) Sonrai (mostly carbonate carbonaceous shale and phosphatic breccia) and (b) Solda Formations (commonly chloritic and...     

Trace elements geochemistry and petrogenesis of basalt from the southern part of the East Pacific Rise

Trace element geochemistry of basalt samples collected from 6°S-24°S of the southern EPR, representing a super-fast spreading axis is discussed. Trace element data classify these basalts into Normal and Transitional types of MORB, however, LREE enrichment is also observed in few of them. Chondrite normalized REE data plots show highly fractionated nature of these lavas, suggesting their derivation from the primitive mantle source. Petrogenetic modeling of the data suggests variation in the solidus pressure (14–20 kb.) and temperature (1316–1425°C), where 15 to 20% partial melting of the mantle is accountable for the generation of the melt. The pressure and temperature conditions at the beginning of the mantle melting were high along higher latitudes (24°S of EPR), but it gradually lowered down in the lower latitudinal areas (6°S of EPR), supporting for the presence of passively rising upper mantle beneath the Southern EPR.     

Longitudinal Distribution of Solar Flares and Their Association with Coronal Mass Ejections and Forbush Decreases

Major Hα solar-flare events of high optical importance have been employed to study their heliographic distribution in longitude around the Sun for the period of 2001 to 2006. A statistical analysis was performed to obtain their relationship with halo/partial-halo CMEs and Forbush decreases (Fds) of cosmic-ray intensity. Our analysis indicates that 63% of the solar flares associated with halo CMEs and Fds occur in the western hemisphere and of 37% of such flares occur in the eastern hemisphere. Similarly, we found that nearly 60% of the solar flares associated with partial- halo CMEs and Fds occur in the western hemisphere and the rest (40%) occur in the eastern hemisphere. Finally, we conclude that the flares in association with CMEs and located in the western hemisphere of the solar disk are more effective in producing Fds. The magnitudes of Fds are observed to be higher when in association of halo CMEs. A slight excess in the eastern hemisphere is found for both the halo and partial-halo CMEs.     

Effects of γ-Rays on Hatching' of the Eggs and Survival Period of Fries of Cyprinus carpio

The eggs of Cyprinus carpio were irradiated by 5 different strengths: 0.0258, 0.129, 0.258, 0.516 and 1.29 C/kg (100, 500, 1000, 2000 and 5000 R) of γ-rays in the batches of 50 fertilized eggs. The activities of eggs and hatched fries were noted after irradiation doses. The hatching percentages of the eggs were reported for each group. The percentage of hatched eggs of Cyprinus carpio after radiation doses of 0.0258, 0.129, 0.258, 0.516 and 1.29 C/kg (100, 500, 1000, 2000 and 5000 R) was 30%, 24%, 28%, 30%, and 34%, respectively. The 50% mortality period of fries for the above strengths of the γ-rays was 8 days, 7 days, 6 days. 4 days and 4 days, respectively. The survival period of the fries was 11 days, 9 days, 8 days, 7 days and 6 days, respectively. All fries hatched from the eggs irradiated by γ-rays showed early hatching, a higher percentage of mortality, a retarded and abnormal development of the body. A statistical analysis of the results by the correlation coefficient also proved that the hatching percentages of the fries and the survival period of fries are directly proportional to the strength of the γ-rays and inversely proportional to the strength of γ-rays, respectively.     

Effect of Coriolis force on the equilibrium structures of rotating stars and stars in binary systems

Kopal (Adv. Astron. Astrophys. 9:1–65, 1972) introduced the concept of Roche equipotentials to incorporate the effects of rotation and tidal distortions on the equilibrium structure and periods of small oscillations of rotating stars and stars in binary systems. However his expression for the Roche equipotential accounts for only the effects of centrifugal and gravitational forces and does not take into account the effect of Coriolis force. In this paper we have suitably modified Kopal’s expression for Roche equipotentials to incorporate into it the effect of Coriolis force as well. The modified expression for the Roche equipotential has then been used to compute the equilibrium structures and shapes of polytropic models of rotating stars and stars in binary systems.