Development of a Fiber Optic Sensor for Online Monitoring of Thin Coatings

 The thickness measurement of gas, liquid and solid layers is not only important for the basic research on nanoscience but equally valuable in contemporary applied biomedical research. Here, we have developed an optical spectroscopy based technique for the online monitoring of thin films (coatings). A low cost light emitting diode (LED) source combined with a fiber optic bundle and grating based spectrograph have been used to generate white light interferogram. We have monitored online change of refractive index of an air film (~4 μm thickness) with temperature following the change in the intensity profile of the interferogram. A thin film of water between two cover slips (thin glass plates) has also been monitored. We have proposed a schematic for further lowering the cost of the developed instrument for the online monitoring of the coating thickness (semitransparent liquid/gas/solid films) during manufacturing/processing. A brief theoretical analysis on the detection limit of the developed technique has also been discussed in the paper

Characterization of a potential CO2 storage complex in the Cambay Basin, India

Introduction High-level studies have identified that there is potential for subsurface storage of CO2 in India (Holloway et al., 2009; Vishal et al., 2021). A major challenge to the deployment of CO2 storage in India is the lack of detailed technical appraisals aimed at understanding and de-risking the storage resource. The vast majority of India’s CO2 storage resource is therefore considered to be undiscovered as per the Society of Petroleum Engineers CO2 Storage Resource Management System (SRMS) scale (SPE, 2017). Given the need to rapidly appraise India’s storage resource to support emission reductions targets, one pragmatic approach would be to first define representative storage complexes in key regions of interest for future CO2 storage developments. Theory and/or Method The notion of a CO2 storage complex is embedded in European legislation, where it provides a means of defining the storage site and surrounding geological domain which can have an effect on overall storage integrity and security, including secondary containment formations (EC, 2009). Defining a storage complex can therefore be a key starting point in identifying the specific site appraisal studies required to gain insight into the likely dynamic behavior of sites during CO2 injection, including the long-term post-injection period. This presentation will investigate how storage projects developed in NW Europe have considered the subsurface lithostratigraphy and structure to define storage complex boundaries. Through interpretation of legacy datasets acquired during legacy oil and gas exploration and development, these principles will then be applied to an area on the flank of the brownfield Gandhar Oil Field in the Cambay Basin, Gujarat. Example The lithostratigraphic determination of a potential storage complex within the Anklesvar Formation is illustrated in Figure 1. The stratigraphy of the Cambay Basin presents the possibility for several different storage concepts. Firstly, hydrocarbon-bearing sandstones of the Mid-Eocene Hazad Member may be suitable for CO2 storage, either following cessation of production, and/or as a beneficial by-product of CO2-enhanced oil recovery. The Hazad Member is sealed by shales of the Kanwa Member. Secondly, marine shales of the overlying Ardol Member provide an additional top seal, while deltaic sandstones are also present over part of the area which present an opportunity for saline aquifer storage. The sand-prone sequences within the Ardol Member may be considered as a storage opportunity in their own right, or in the context of secondary storage in the event of CO2 storage in the Hazad Member. The storage complex is capped by shales of the Telwa Member, which exhibits a variable thickness distribution across the region. The regionally extensive Y Marker in the Upper part of the Cambay Shale provides a reliable seismic reflector which can conveniently be used to define the lower storage complex boundary. In this way, thin impersistent sandstones in the upper part of the Cambay Shale are also incorporated within the storage complex. Evaluation of legacy oil and gas datasets have enabled mapping of the distribution, thickness and structural disposition of the reservoir and top seal units. This has enabled a high-level assessment of the storage potential and associated storage risks to be determined. The spatial arrangement of reservoir sands in the Hazad and Ardol Members is controlled by frequent fluctuations between transgressive and regressive sequences, and the direction of sediment input. The deltaic sands of the Hazad Member are mainly sourced from the Northeast, and are covered by transgressive shales of the Kanwa Member. Changes in baselevel and sediment input direction have influenced the distribution of the Ardol Member, leading to an uneven distribution of sands. The Telwa shale, acting as the regional seal, experiences occasional erosion beneath a second-order erosional unconformity. No major faults offset the storage complex in the study area, with the primary risk being the presence of down-cutting sandstone units affecting the Kanwa and/or Telwa member top seals. A number of key recommendations for further detailed appraisal have been identified, including the requirement to accurately determine the volumes of sandstone available for CO2 storage capacity estimations, and the requirement to carefully characterize the thickness of the Telwa Member as the ultimate top seal. Finally, the high number of legacy oil and gas wells in the region will necessitate detailed well integrity studies. Conclusions We have demonstrated for the first time how application of the storage complex concept can be applied to an onshore sedimentary basin in India. The study has enabled identification of specific activities that will be required to fully understand the CO2 storage potential of the region. These measures relate to the quantification of storage capacity, the likely dynamic behavior of the site, and the understanding of containment risk and natural barriers

PALEO HYDRATE AND ITS ROLE IN DEEP WATER PLIO-PLEISTOCENE GAS RESERVOIRS IN KRISHNA-GODAVARI BASIN, INDIA

Discovery of natural methane hydrate in deepwater sediments in the east-coast of India have generated significant interest in recent times. This work puts forward a possible relationship of multi-TCF gas accumulation through destabilization of paleo-hydrate in Plio-Pleistocene deepwater channel sands of Krishna-Godavari basin, India. Analysis of gas in the study area establishes its biogenic nature, accumulation of which is difficult to explain using the elements of conventional petroleum system. Gas generated in sediments by methanogenesis is mostly lost to the environment, can however be retained as hydrate under suitable conditions. Longer the time a layer stayed within the gas hydrate stability zone (GHSZ) greater is the chance of retaining the gas which can be later released by change in P-T conditions due to sediment burial. P-T history for selected stratigraphic units from each well is extracted using 1-D burial history model and analyzed. Hydrate stability curves for individual units through time are generated and overlain in P-T space. It transpired that hydrate formation and destabilization in reservoir units of same stratigraphic level in different wells varies both in space and time. Presence of paleo hydrates is confirmed by the occurrence of authigenic carbonate cement and low-saline formation water. We demonstrate how gas released by hydrate destabilization in areas located at greater water depths migrates laterally and updip along the same stratigraphic level to be entrapped in reservoirs which is outside the GHSZ. In areas with isolated reservoirs with poor lateral connectivity, the released gas may remain trapped if impermeable shale is overlain before the destabilization of hydrate. The sequence of geological events which might have worked together to form this gas reservoir is: deposition of organic rich sediments → methanogenesis → gas hydrate formation → destabilization of hydrate and release of gas → migration and entrapment in reservoirs.Non UBCUnreviewe

A New Method For Rapid Detection Of Total Colour (TC), Theaflavins (TF), Thearubigins (TR) and Brightness (TB) In Orthodox Teas

Theaflavins (TF) and thearubigins (TR) are the important chemical compounds, which contribute to the colour and brightness of tea liquor. Estimation of TF and TR in black tea is generally done using a spectrophotometer. But, the analysis technique undergoes rigorous time consuming effort for sample preparation; also the operation of costly spectrophotometer requires expert manpower. To overcome above problems an electronic vision system (E-Vision system) based on image processing has been developed, which is faster, low cost, repeatable and can estimate the amount of Total Colour (TC), Brightness (TB), Theaflavins (TF) and TF/TR ratio for orthodox tea liquors. This paper describes the newly developed E-Vision system, experimental methods using orthodox black tea sample, data analysis algorithms and finally, the performance of the E-Vision system as compared to the results of traditional spectrophotometer. The data analysis is done using Principal Component Analysis (PCA) and Multiple Linear Regression (MLR). A correlation has been established between colour of tea liquor images and TC, TB, TR and TF/TR ratio

Spectroscopic Studies on Dual Role of Natural Flavonoids in Detoxification of Lead Poisoning: Bench-to-Bedside Preclinical Trial

Ubiquitousness in the target organs and associated oxidative stress are the most common manifestations of heavy-metal poisoning in living bodies. While chelation of toxic heavy metals is important as therapeutic strategy, scavenging of increased reactive oxygen species, reactive nitrogen species and free radicals are equally important. Here, we have studied the lead (Pb) chelating efficacy of a model flavonoid morin using steady-state and picosecond-resolved optical spectroscopy. The efficacy of morin in presence of other flavonoid (naringin) and polyphenol (ellagic acid) leading to synergistic combination has also been confirmed from the spectroscopic studies. Our studies further reveal that antioxidant activity (2,2-diphenyl-1-picrylhydrazyl assay) of the Pb–morin complex is sustainable compared to that of Pb-free morin. The metal–morin chelate is also found to be significantly soluble compared to that of morin in aqueous media. Heavy-metal chelation and sustainable antioxidant activity of the soluble chelate complex are found to accelerate the Pb-detoxification in the chemical bench (in vitro). Considering the synergistic effect of flavonoids in Pb-detoxification and their omnipresence in medicinal plants, we have prepared a mixture (SKP17LIV01) of flavonoids and polyphenols of plant origin. The mixture has been characterized using high-resolution liquid chromatography assisted mass spectrometry. The mixture (SKP17LIV01) containing 34 flavonoids and 76 other polyphenols have been used to investigate the Pb detoxification in mouse model. The biochemical and histopathological studies on the mouse model confirm the dual action in preclinical studies

A Robust Electrochemical Sensor Based on Butterfly-shaped Silver Nanostructure for Concurrent Quantification of Heavy Metals in Water Samples

Heavy metals in drinking water have become a severe threat to human health. Detection of heavy metals has been achieved by electrochemical sensors that are modified with complex nanocomposites; however, reproducibility of these sensors is still a big challenge when applied in commercial settings. Here, a simple, very robust, and sensitive electrochemical sensor based on a screen-printed carbon electrode modified with butterfly-shaped silver nanostructure (AgNS/SPCE) has been developed for the concurrent determination of cadmium (II), lead (II), copper (II), and mercury (II) in water samples. The electrochemical behavior of the modified electrodes was investigated using cyclic voltammetry and differential pulse anodic stripping voltammetry. The AgNS/SPCE showed distinct peak potentials and a significant increase in the peak currents for all heavy metals, attributed to the high electrical conductivity and electrocatalytic activity of the synthesized butterfly-shaped AgNS. Moreover, the excellent stability and sensitivity towards simultaneous quantification of heavy metals have been obtained with detection limits of 0.4 ppb, 2.5 ppb, 7.3 ppb, and 0.7 ppb for Cd (II), Pb (II), Cu (II), and Hg (II), respectively. Besides, the constructed sensor was successfully applied to simultaneously quantify target heavy metals in spiked water samples. Owing to excellent sensitivity, high robustness, affordability, and fast response, the presented electrochemical sensor could be incorporated into a portable and miniaturized potentiostat device, making it a promising method for on-site water analysis