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1. Creeping Gas Hydrate Slides

   https://doi.org/10.14379/iodp.proc.372A.2019  

   Pecher, I.A.; Barnes, P.M.; LeVay, L.J. (May 2019, Proceedings of the International Ocean Discovery Program)

   null (Ed.)

   International Ocean Discovery Program (IODP) Expedition 372 combined two research topics: actively deforming gas hydrate–bearing landslides (IODP Proposal 841-APL) and slow slip events on subduction faults (IODP Proposal 781A-Full). This expedition included a coring and logging-while-drilling (LWD) program for Proposal 841-APL and a LWD program for Proposal 781A-Full. The coring and observatory placement for Proposal 781A-Full were completed during Expedition 375. The Expedition 372A Proceedings volume focuses only on the results related to Proposal 841-APL. The results of the Hikurangi margin drilling are found in the Expedition 372B/375 Proceedings volume. Gas hydrates have long been suspected of being involved in seafloor failure. Not much evidence, however, has been found to date for gas hydrate–related submarine landslides. Solid, ice-like gas hydrate in sediment pores is generally thought to increase seafloor strength, which is confirmed by a number of laboratory measurements. Dissociation of gas hydrate to water and overpressured gas, on the other hand, may weaken and destabilize sediments, potentially causing submarine landslides. The Tuaheni Landslide Complex (TLC) on the Hikurangi margin shows evidence for active, creeping deformation. Intriguingly, the landward edge of creeping coincides with the pinch-out of the base of gas hydrate stability on the seafloor. We therefore proposed that gas hydrate may be involved in creep-like deformation and presented several hypotheses that may link gas hydrates to slow deformation. Alternatively, creeping may not be related to gas hydrates but instead be caused by repeated pressure pulses or linked to earthquake-related liquefaction. Plans for Expedition 372A included a coring and LWD program to test our landslide hypotheses. Because of weather-related downtime, the gas hydrate–related program was reduced and we focused on a set of experiments at Site U1517 in the creeping part of the TLC. We conducted a LWD and coring program to 205 m below the seafloor through the TLC and the gas hydrate stability zone, followed by temperature and pressure tool deployments. 

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2. Polymorphs, Solvatomorphs, Hydrate, and Perhydrate of Dabrafenib

   https://doi.org/10.1021/acs.cgd.2c01289  

   Rai, Sunil K.; Gunnam, Anilkumar; Beran, Gregory J.; Kaduk, James A.; Nangia, Ashwini K. (February 2023, Crystal Growth & Design)
3. Enhancement of Hydrate Stability through Substitutional Defects

   https://doi.org/10.1021/acs.cgd.3c00457  

   Fleming, Megan E.; Swift, Jennifer A. (June 2023, Crystal Growth & Design)
4. Nanolayered attributes of calcium‐silicate‐hydrate gels

   https://doi.org/10.1111/jace.16750  

   Masoumi, Saeed; Ebrahimi, Davoud; Valipour, Hamid; Abdolhosseini_Qomi, Mohammad_Javad (September 2019, Journal of the American Ceramic Society)

   Abstract Calcium‐silicate‐hydrates (C–S–H) gel, the main binding phase in cementitious materials, has a complex multiscale texture. Despite decades of intensive research, the relation between C–S–H's chemical composition and mesoscale texture remains experimentally limited to probe and theoretically elusive to comprehend. While the nanogranular texture explains a wide range of experimental observations, understanding the fundamental processes that control particles’ size and shape are still obscure. This paper strives to establish a link between the chemistry of C–S–H nanolayers at the molecular level and formation of C–S–H globules at the mesoscale via the potential‐of‐mean‐force (PMF) coarse‐graining approach. We propose a new thermomechanical load‐cycling scheme that effectively packs polydisperse coarse‐grained nanolayers and creates representative C–S–H gel structures at various packing densities. We find that the C–S–H nanolayers percolate at ~10% packing fraction, significantly below the percolation of ideal hard contact oblate particles and rather close to that of overlapping ellipsoids. The agglomeration of C–S–H nanolayers leads to the formation of globular clusters with the effective thickness of ~5 nm, in striking agreement with small angle neutron and X‐ray scattering measurements as well as nanoscale imaging observations. The study of pore structure and local packing distribution in the course of densification shows a transition from a connected pore network to isolated nanoporosity. Furthermore, the calculated mechanical properties are in excellent agreement with statistical nanoindentation experiments, positioning nanolayered morphology as a finer description of C–S–H globule models. Such high‐resolution description becomes indispensable when investigating phenomena that involve internal building blocks of globules such as shrinkage and creep. 

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5. Hydrate Transformation via Anhydrate Pairs

   https://doi.org/10.1021/acs.cgd.0c00655  

   Thornton, Alyssa M.; Hall, Victoria M.; Swift, Jennifer A. (September 2020, Crystal Growth & Design)

   null (Ed.)