Buckling of Piles under Liquefied Soil Conditions

The paper pertains to the analysis of piles embedded in liquefiable soils to predict its’ critical buckling load under partial to full loss of lateral support over a portion of the pile length. The analysis is based on extension of Mindlin solution for a point load acting inside a semi infinite elastic half space. Degenerated solutions obtained by using the developed method compares very well with reported results. Parametric studies showed that the depth of liquefiable soil, degradation of soil strength on liquefaction, slenderness ratio, pile stiffness factor and end conditions have significant influence on the buckling behavior of the piles.     

Free vibration of semisubmersibles: A parametric study

Like any other engineering structure, the dynamic aspects of semisubmersible offshore platforms require serious consideration. The free vibrations of the semisubmersible structures have been investigated in the present work, in which the effect of the variation of the length, draft and hull spacings on the natural frequencies and mode shapes has been studied and the nature of the variations and their reasons have been discussed.     

http://www.sciencedirect.com/science/article/pii/S1674987112000072

The Abor volcanics outcroping in the core of the Siang window in the Eastern Himalaya comprise voluminous mafic volcanics (47％-56％ w(SiO2)),with subordinate felsic volcanics (67％-75％ w(SiO2)).The felsi...     

Role of dykes in induced seismicity at Bhatsa reservoir,Maharashtra, India

The geological and hydrological conditions near the reservoir site play an important role in the generation or absence of seismic activity. Near Bhatsa reservoir, along the west coast of India intense seismic activity occurred during August–September 1983, after a lag of six years of initial impounding. From July 1983 to September 1990, 15,388 earthquakes (mostlyM ₁<3.0) were recorded, the largest being of magnitude 4.9. The spatial distribution of well located 172 earthquakes suggest a strong correlation between the epicenters and the disposition of dykes and faults around the Bhatsa region. It is inferred that these dykes have acted as barriers for the diffusion of water from the reservoir, thereby becoming zones of instability due to increased pore pressure not only along them but also over the volume they bound.     

Whose carbon is burnable? Equity considerations in the allocation of a “right to extract”

Carbon emissions—and hence fossil fuel combustion—must decline rapidly if warming is to be held below 1.5 or 2 °C. Yet fossil fuels are so deeply entrenched in the broader economy that a rapid transition poses the challenge of significant transitional disruption. Fossil fuels must be phased out even as access to energy services for basic needs and for economic development expands, particularly in developing countries. Nations, communities, and workers that are economically dependent on fossil fuel extraction will need to find a new foundation for livelihoods and revenue. These challenges are surmountable. In principle, societies could undertake a decarbonization transition in which they anticipate the transitional disruption, and cooperate and contribute fairly to minimize and alleviate it. Indeed, if societies do not work to avoid that disruption, a decarbonization transition may not be possible at all. Too many people may conclude they will suffer undue hardship, and thus undermine the political consensus required to undertake an ambitious transition. The principles and framework laid out here are offered as a contribution to understanding the nature of the potential impacts of a transition, principles for equitably sharing the costs of avoiding them, and guidance for prioritizing which fossil resources can still be extracted.     

Boundary-layer depth and entrainment zone characterization with a boundary-layer profiler

A technique for determining the height of the convective atmospheric boundary layer (CBL) with a 915 MHz boundary-layer profiler is discussed. The results are compared with CBL heights determined from radiosonde measurements. The profiler provides continuous CBL height measurements with very good time resolution (30 minutes or less), allowing for detailed understanding of the growth and fluctuations of the CBL. In addition, the profiler provides information about the degree of definition of the CBL top and the thickness of the entrainment zone. The measurements discussed were taken during the Rural Oxidants in the Southern Environment II (ROSE II) experiment.     

Reanalysis of seasonal and interannual variability of Black Sea fields for 1993–2012

A retrospective analysis has been done for the hydrophysical fields of the Black Sea for 1993–2012 with the assimilation of undisturbed monthly average profiles of temperature and salinity that were obtained by using an original procedure of joint processing of satellite altimetry and rare hydrological observations. The accuracy of the reconstructed fields of temperature and salinity of the Black Sea is evaluated by comparison with the data of sounding from the hydrological stations and the Argo floats. A comparative analysis is performed for the integral characteristics of the fields of temperature, salinity, and kinetic energy with the same characteristics of the reanalysis for 1992–2012 that assimilated the average annual profiles of temperature and salinity, surface temperature and altimetry level of the sea after being adjusted with respect to climate seasonal variability. The proposed procedure of the reanalysis execution allows a more precise reconstruction of the interannual variability of temperature and salinity stratification in the main pycnocline. The correlation between the annual and seasonal variability of the eddy of the wind friction tangential stress and the average kinetic energy at the levels is revealed.     

Trends in the solubility of iron,aluminium, manganese and phosphorus in aerosol collected over the Atlantic Ocean

The solubility of iron, aluminium, manganese and phosphorus has been determined in aerosol samples collected between 49°N and 52°S during three cruises conducted in the Atlantic Ocean as part of the European Union funded IRONAGES programme. Solubilities (defined at pH 4.7) determined for Fe and Al in samples of Saharan dust were significantly lower (medians 1.7% and 3.0%, respectively) than the solubilities of these metals in aerosols from other source regions (whole dataset medians 5.2% and 9.0%, respectively). Mn solubility also varied with aerosol source, but the median solubility of Mn in Saharan dust was very similar to the median for the dataset as a whole (55% and 56%, respectively). The observed solubility of aerosol P was ∼ 32%, with P solubility in Saharan aerosol perhaps as low as 10%. Laboratory studies have indicated that aerosol Fe solubility is enhanced by acid processing. No relationship could be found between Fe solubility and the concentrations of acid species (non-seasalt SO₄²⁻, NO₃⁻) nor the net acidity of the aerosol, so we are unable to confirm that this process is significant in the atmosphere. In terms of the supply of soluble Fe to oceanic ecosystems on a global scale, the observed higher solubility for Fe in non-Saharan aerosols is probably not significant because the Sahara is easily the dominant source of Fe to the Atlantic. On a smaller scale however, higher solubility for aerosol Fe may alter our understanding of Fe cycling in regions such as the remote Southern Ocean.     

Seismic hazard assessment and mitigation in India: an overview

The Indian subcontinent is characterized by various tectonic units viz., Himalayan collision zone in North, Indo-Burmese arc in north-east, failed rift zones in its interior in Peninsular Indian shield and Andaman Sumatra trench in south-east Indian Territory. During the last about 100 years, the country has witnessed four great and several major earthquakes. Soon after the occurrence of the first great earthquake, the Shillong earthquake (M _w: 8.1) in 1897, efforts were started to assess the seismic hazard in the country. The first such attempt was made by Geological Survey of India in 1898 and since then considerable progress has been made. The current seismic zonation map prepared and published by Bureau of Indian Standards, broadly places seismic risk in different parts of the country in four major zones. However, this map is not sufficient for the assessment of area-specific seismic risks, necessitating detailed seismic zoning, that is, microzonation for earthquake disaster mitigation and management. Recently, seismic microzonation studies are being introduced in India, and the first level seismic microzonation has already been completed for selected urban centres including, Jabalpur, Guwahati, Delhi, Bangalore, Ahmadabad, Dehradun, etc. The maps prepared for these cities are being further refined on larger scales as per the requirements, and a plan has also been firmed up for taking up microzonation of 30 selected cities, which lie in seismic zones V and IV and have a population density of half a million. The paper highlights the efforts made in India so far towards seismic hazard assessment as well as the future road map for such studies.