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Polymer-Cement Composites with Self-Healing Ability for Geothermal and Fossil Energy Applications
Childers, M. Ian,Nguyen, Manh-Thuong,Rod, Kenton A.,Koech, Phillip K.,Um, Wooyong,Chun, Jaehun,Glezakou, Vassiliki-Alexandra,Linn, Diana,Roosendaal, Timothy J.,Wietsma, Thomas W.,Huerta, Nicolas John American Chemical Society 2017 Chemistry of materials Vol.29 No.11
<P>Sealing of wellbores in geothermal and tight oil/gas reservoirs by filling the annulus with cement is a well-established practice. Failure of the cement as a result of physical and/or chemical stress is a common problem with serious environmental and financial consequences. Numerous alternative cement blends have been proposed for the oil and gas industry. Most of these possess poor mechanical properties, or are not designed to work in high temperature environments. This work reports on a novel polymer-cement composite with remarkable self-healing ability that maintains the required properties of typical wellbore cements and may be stable at most geothermal temperatures. We combine for the first time experimental analysis of physical and chemical properties with density functional theory simulations to evaluate cement performance. The thermal stability and mechanical strength are attributed to the formation of a number of chemical interactions between the polymer and cement matrix including covalent bonds, hydrogen bonding, and van der Waals interactions. Self-healing was demonstrated by sealing fractures with 0.3–0.5 mm apertures, 2 orders of magnitude larger than typical wellbore fractures. This polymer-cement composite represents a major advance in wellbore cementing that could improve the environmental safety and economics of enhanced geothermal energy and tight oil/gas production.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2017/cmatex.2017.29.issue-11/acs.chemmater.7b00344/production/images/medium/cm-2017-00344c_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm7b00344'>ACS Electronic Supporting Info</A></P>
Kim, Daeji,Croudace, Ian W.,Warwick, Phillip E. Elsevier 2012 Journal of hazardous materials Vol.213 No.-
<P><B>Highlights</B></P><P>► Identification of variation in tritium loss rates in concrete samples. ► Quantification of variation in tritium loss rates under different storage conditions. ► Quantification of tritium cross-contamination rates for a range of matrix types. ► Storage strategies for routine waste characterisation involving tritium.</P> <P><B>Abstract</B></P><P>Large volumes of potentially tritium-contaminated waste materials are generated during nuclear decommissioning that require accurate characterisation prior to final waste sentencing. The practice of initially determining a radionuclide waste fingerprint for materials from an operational area is often used to save time and money but tritium cannot be included because of its tendency to be chemically mobile. This mobility demands a specific measurement for tritium and also poses a challenge in terms of sampling, storage and reliable analysis. This study shows that the extent of any tritium redistribution during storage will depend on its form or speciation and the physical conditions of storage. Any weakly or moderately bound tritium (e.g. adsorbed water, waters of hydration or crystallisation) may be variably lost at temperatures over the range 100–300°C whereas for more strongly bound tritium (e.g. chemically bound or held in mineral lattices) the liberation temperature can be delayed up to 800°C. For tritium that is weakly held the emanation behaviour at different temperatures becomes particularly important. The degree of <SUP>3</SUP>H loss and cross-contamination that can arise after sampling and before analysis can be reduced by appropriate storage. Storing samples in vapour tight containers at the point of sampling, the use of triple enclosures, segregating high activity samples and using a freezer all lead to good analytical practice.</P>
Hyeon-kyeong Cho,Eun-kyoung Yang,Hee-suk Han,Won-jung Lee,M. Ian Phillips 대한생리학회-대한약리학회 2000 The Korean Journal of Physiology & Pharmacology Vol.4 No.2
<P> The physiological roles of brain angiotensin II in mediating water deprivation-induced drinking and in regulating renal renin release were assessed in male Sprague-Dawley rats. Specific AT<SUB>1</SUB> receptor antagonists, losartan and SK 1080, and antisense oligonucleotide (AS-ODN) directed to AT<SUB>1</SUB> receptor mRNA were intracerebroventricularly (i.c.v.) administered in conscious unrestrained rats. When water was given 20 min after i.c.v. injection of AT<SUB>1</SUB> receptor antagonists in 48-h water-deprived rats, losartan and SK 1080 produced approximatly 20% and 50% decrease in 1-h water intake, respectively. In contrast, i.c.v. treatment of the AS-ODN to AT<SUB>1 </SUB>receptor mRNA for 24-h did not alter 1-h water intake in 24-h water-deprived rats, but prevented the increase in overnight water intake after 24-h water-deprivation. Six-day i.c.v. treatment of AS-ODN did not alter either the basal plasma renin concentration or renal cortical levels of renin and renin mRNA. The present results suggest that endogenous brain Ang II plays an important role in thirst and water intake through AT<SUB>1</SUB> receptors, but further studies are required to elucidate its regulatory role in renal renin synthesis.