Evaluation of Effect of 17% EDTA and 5.25% Sodium Hypochloride Irrigating Solutions on Surface Hardness of Brasseler Endosequence Root Repair Material

Introduction: Root Perforation is an artificial communication between the root canal system and supporting tissue. Various endodontic researchers have published that sealing the perforation immediately has the best prognosis but this predisposes the repair material to come in contact with various root canal irrigants during the course of treatment. The aim of this study was to evaluate the effect of 17% EDTA and 5.25% sodium hypochlorite irrigating solutions on surface hardness of Endosequence Root Repair Material Putty (ERRM). Method: ERRM, 5.25% Sodium Hypochlorite, 17% EDTA and Deionized water were used. 42 samples were prepared and divided into 2 groups. Each group was divided in three sub groups. Sub Groups in Group I were stored in water, 5.25% NaOCl and 17% EDTA for 7 days and were subjected to hardness testing. After 7 days Group II samples were exposed to water, 5.25% NaOCl, 17% EDTA for 10 minutes and 7 days and were subjected to Vickers microhardness tester for hardness testing. Non-Parametric tests were used due to lack of normalcy of the data. Results: Exposure of ERRM to water, 17% EDTA, and 5.2% NaOCl during setting over 7 days had no significant effect on the microhardness of ERRM. NaOCl exposed samples were significantly harder than samples exposed to water for 10 minutes and 7 days. Exposure to EDTA resulted in significantly lower microhardness. Conclusion: 1. Exposure of ERRM to water, 17% EDTA, and 5.2% NaOCl during setting over 7 days had no significant effect on the microhardness of ERRM. 2. Additional exposure to Water or 17% EDTA for 10 minutes reduced the microhardness possibly due to excessive hydration by water resulting in a porous matrix and acidic nature plus calcium depletion by EDTA interfering with the C-S-H gel structure of ERRM. 3. NaOCl (5.25%) increased the microhardness possibly due to non-inhibition of calcium hydroxide formation on the surface and increasing the number and size of the surface crystal. 4. Exposure to extended period of 17% EDTA had detrimental effects on ERRM and samples lacked structural integrity

Study of geochemical interactions during chemical EOR processes

Geochemical interactions of injected fluids with reservoir fluids and minerals determine the fate of the injected species in the porous media. In addition, these interactions could result in affecting the properties of the porous media such as permeability, porosity, and wettability. With a growing energy demand and continuous depletion of easy oil, chemical enhanced oil recovery (CEOR) techniques are being investigated to satisfy future energy needs. An understanding of geochemical interactions that occur during CEOR techniques is essential to make these processes robust and economical, and make reliable field predictions. In this study, geochemical interactions during alkali surfactant polymer (ASP) floods and low salinity wettability alteration in carbonates were investigated. Experiments were performed to understand interactions of various alkalis in sandstone and carbonate cores containing gypsum. The experiments included single-phase static and transport experiments, surfactant phase behavior experiments and oil recovery corefloods. The ionic compositions of aqueous solutions were carefully monitored to understand the geochemical interactions of these alkalis. The effect of injection rate was investigated to understand if reactions reached equilibrium at the injection rates typically used in lab corefloods. The study showed sodium metaborate to be most suitable, in comparison to sodium carbonate, sodium hydroxide and sodium silicate, for sandstone and carbonate cores containing gypsum. The reaction of sodium metaborate with gypsum was found to be rate dependent and did not reach equilibrium in the lab corefloods. Ammonia was investigated as an alternative alkali for ASP floods. Single-phase static and transport experiments were performed to study its interactions with gypsum. Single-phase static and transport experiments were performed to investigate the effect of adding ammonia on surfactant adsorption. Zeta potential measurements were performed using ammonia and sodium carbonate. Ultralow IFT surfactant formulations were developed, using ammonia as the alkali, for cores containing gypsum or otherwise. Polymer stability experiments were performed to identify polymers suitable for ASP corefloods in cores containing gypsum using ammonia as the alkali. The results showed ammonia to maintained a high pH in presence of gypsum without causing any calcium precipitation. The dissolved calcium ions, however, affected surfactant phase behavior and polymer stability. Single-phase static and transport surfactant adsorption experiments showed reduction in surfactant adsorption on sandstones by adding ammonia. The surfactant adsorption results were, however, not obvious for carbonates when ammonia was used as the alkali. Good oil recoveries and low surfactant retentions were observed during ASP corefloods in sandstone and carbonate cores using ammonia. Interaction of various alkalis with acidic crude oils was also investigated to develop low-cost alkali cosolvent polymer (ACP) floods for such oils. Alkali scans were performed with various alkalis (with and without adding a cosolvent) and low IFT regions were identified. The effect of cosolvent type and divalent cations on the phase behavior results was investigated. ACP corefloods were performed in sandstone cores. The phase behavior experiments showed low IFT regions to vary for different alkalis. ACP corefloods showed good oil recoveries in sandstone cores. Single-phase static and transport experiments were performed to understand geochemical interactions during low salinity waterfloods in carbonate cores at high temperatures. Various low-salinity brines were injected in a limestone core and the ionic composition of the effluent samples were monitored. The effect of injection rate on the composition of the effluent ions was investigated. The experiments showed calcite dissolution, dolomitization and sulfate adsorption to occur on injecting low-salinity brines in limestone cores at high temperatures. The reactions reached equilibrium within 2 PV at 1 ft/d when seawater was injected in a limestone core, initially saturated with the formation brine. However, the reactions did not reach equilibrium when the SW was subsequently displaced with SW/50, even after injecting more than 3 PV. Modeling and simulation work was performed with PHREEQC, UTCHEM and UTCHEM-IPHREEQC to model lab experiments. Single-phase alkali floods and oil recovery corefloods performed using sodium metaborate and ammonia were simulated. A good agreement was obtained between experimental and simulation results. The effect of ion exchange reactions on surfactant floods was investigated. In addition, a mechanistic model was developed for low-salinity wettability alteration in carbonates by incorporating key geochemical interactions observed during the experiments. The model results showed good agreement with effluent ions of static and dynamic experiments, assuming local equilibrium. A good agreement of modeling results was observed with the low salinity oil recovery corefloods reported in the literature.Petroleum and Geosystems Engineerin

Shattered Dreams and Identity Crisis: A Critical Analysis of Bharati Mukherjee’s Wife

The Earth is a place to live in for all the creatures. Human beings have controlled on many natural activities due to his advance of science and technology. Going from one place to another place has been made very easy. Bharati Mukherjee has been in the news recently because her demise on 28th January, 2017 has given a big shock to her fans, students, colleagues and even critics. She has taken the theme of gender discrimination, cultural clash and identity crisis in her novels. Her novels deal with the issues of the dreams which shattered on an alien land. People go to a foreign land with so many colourful dreams in their minds but they do not think about the challenges of a foreign land where culture, language, eating habits etc. are totally different. Present chapter is an analysis of Bharati Mukherjee’s novel Wife. This novel has emerged as a saga of unfulfilled dreams of a wife Dimple Das Gupta who is a very ambitious woman. She lives in an imaginary world beyond her limitations and above the reality of the earthly life. The works results as a tragedy when she murders her own husband and thinks that nobody will surrender her like the TV serials. Thus, this paper explores the whims of Dimple and her broken dreams in this novel