Development of an unsupervised remote sensing methodology of detect surface leakage from terrestrial CO2 storage sites

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Noncommutative Tachyons

When unstable Dp-branes in type II string theory are placed in a B-field, the resulting tachyonic world-volume theory becomes noncommutative. We argue that for large noncommutativity parameter, condensation of the tachyon as a noncommutative soliton leads to new decay modes of the Dp-brane into (p-2)-brane configurations, which we interpret as suitably smeared BPS D(p-1)-branes. Some of these configurations are metastable. We discuss various generalizations of this decay process.Comment: 15 pages, harvmac (b

Comments on Cosmological Singularities in String Theory

We compute string scattering amplitudes in an orbifold of Minkowski space by a boost, and show how certain divergences in the four point function are associated with graviton exchange near the singularity. These divergences reflect large tree-level backreaction of the gravitational field. Near the singularity, all excitations behave like massless fields on a 1+1 dimensional cylinder. For excitations that are chiral near the singularity, we show that divergences are avoided and that the backreaction is milder. We discuss the implications of this for some cosmological spacetimes. Finally, in order to gain some intuition about what happens when backreaction is taken into account, we study an open string rolling tachyon background as a toy model that shares some features with R^{1,1}/Z.Comment: harvmac, 40 pages; v2: references adde

Matter from Toric Geometry

We present an algorithm for obtaining the matter content of effective six-dimensional theories resulting from compactification of F-theory on elliptic Calabi-Yau threefolds which are hypersurfaces in toric varieties. The algorithm allows us to read off the matter content of the theory from the polyhedron describing the Calabi-Yau manifold. This is based on the generalized Green-Schwarz anomaly cancellation condition.Comment: 19 pages, Plain TeX, 2 figure

Dermatological manifestations in PLHIV visiting link ART centre at rural medical college hospital in Western Tamilnadu, India

Background: Ever since the early reports of human immuno deficiency infection, it presented as wide range of infectious and non-infectious dermatoses which correlate with the degree of immunodeficiency. Skin assessment remains a vital tool in the diagnosis and management of HIV infection due to relative easiness of examination. Most of skin diseases are amenable to diagnosis by inspection and biopsy. In this descriptive study, we have enumerated in detail the dermatological manifestations of Link ART centre clients.Methods: To analyze the dermatological manifestations in people living with HIV, we undertook a prospective observational study of all PLHIV on ART visiting IRT Perundurai Medical College Hospital link anti- retroviral therapy centre (LAC) during July 2015 to August 2016 with focus to skin manifestations.Results: Among the 140 clients, 22 in 2010, 12 in 2011, 6 in 2012, 51 in 2013, 36 in 2014, and 9 in 2015, 3 up to June 2016 enrolled for follow up. 31 were transferred to nearby ART, Link ART centres during this period as per their request, 4 lost for follow up and 6 deceased after enrolment, finally ninety-nine (39 male; 60 female) were utilizing our centre during the study period. Majority of participants were on ZLN (zidovudine, lamivudine, and nevirapine) regimen, hailing from rural zones, belonged to low or low middle income group, were undertaking farming, cattle rearing. CD4 counts of the asymptomatic clients in the ZLN group noted increase and decrease in the ZLE (zidovudine, lamivudine, and efavirenz), TLN (tenofovir, lamivudine, and nevirapine) group.  In the symptomatic clients, decline in the individual and the mean counts except in female ZLN subset. 70% were clinically asymptomatic and 30 % were having some dermatological manifestations. Multiple manifestations were seen in 5 clients during the study period. Dermatological manifestations observed commonly were fungal and viral infections, xerosis/ichthyoses, adverse drug reactions like lipodystrophy, and discoloration of nails.Conclusions: Skin manifestations observed in this study were due to aging and long term cosmetic side effects of highly active antiretroviral therapy  (HAART). Lipodystrophy posed significant aesthetic distress in HAART clients. Hence, early management would decrease the most offending cosmetolgical side effects of the disease and drugs. Therapy yields the declining trend in the inflammatory, infectious dermatoses

Duality and Non-Commutative Gauge Theory

We study the generalization of S-duality to non-commutative gauge theories. For rank one theories, we obtain the leading terms of the dual theory by Legendre transforming the Lagrangian of the non-commutative theory expressed in terms of a commutative gauge field. The dual description is weakly coupled when the original theory is strongly coupled if we appropriately scale the non-commutativity parameter. However, the dual theory appears to be non-commutative in space-time when the original theory is non-commutative in space. This suggests that locality in time for non-commutative theories is an artifact of perturbation theory.Comment: 7 pages, harvmac; a typo fixe

Calculation of pressure- and migration-constrained dynamic CO2 storage capacity of the North Sea Forties and Nelson dome structures

This paper presents a numerical simulation study of CO2 injection into the Forties and Nelson dome structures in the North Sea. The study assumes that these structures are fully depleted of their remaining hydrocarbon and brine has replaced their pore space, and therefore the structures can be treated as saline aquifers. Under this assumption, the objective is to calculate the dynamic CO2 storage capacity of the Forties and Nelson structures and design an injection scenario to enhance storage utilisation. In doing so, first, a detailed geological model of the dome structures and their surrounding aquifer is developed to represent the lithological facies associations and attribute them with petrophysical properties. The geological model is calibrated in terms of the surrounding aquifer support using the hydrocarbon production data. The dynamic storage capacity is subsequently estimated by numerical simulation of the two-phase (brine and CO2) process. Key performance indicators (KPIs), such as the pressure build-up and regional mass fraction of CO2, are used to constrain the injection scenarios that consequently result in the best capacity utilisation of the storage structures. In our model of fully brine saturated dome structures, based on specific constraints, namely <0.1% of the total gaseous CO2 outside the dome into an upper pressure unit and 66% of the initial hydrostatic pressure as the allowable increase in the bottom-hole pressure, we obtained a dynamic capacity of 121 million tonnes for the Forties structure and 24 million tonnes for the Nelson structure. These values are subject to change when a three phase model of residual oil, gas and water is considered in simulations

RECURRENCE QUANTIFICATION ANALYSIS OF SYSTEM SIGNALS FOR DETECTING TOOL WEAR IN A LATHE

ABSTRACT The work investigates applicability of recurrence quantification analysis (RQA) in metal cutting with an objective to detect tool wear. The effectiveness of applying a system input signal; the drive motor current, in relation to a system output signal; the tool vibration, for the analysis is also explored. The work establishes conclusively that three of the RQA variables, percent determinism, percent recurrence and entropy are sensitive to tool wear