Using Metal-Organic Frameworks to Determine the Crystal Structures of Non-Crystalline Compounds via the Crystalline Sponge Method

The Crystalline Sponge Method has been expanded to the structural elucidation of hydrophilic and non-aromatic compounds through the study of new potential crystalline sponges and a range of novel host-guest inclusion complexes have been presented. First, it was important to reliably synthesise high quality single crystals of the original crystalline sponge {[(ZnI2)3(TPT)2].x(solvent)}n and its ZnBr2 and ZnCl2 variants. Then crystals of these metal-organic frameworks could be used in guest encapsulation experiments. Initial encapsulation experiments focused on improving on work performed previously in the Carmalt group on the encapsulation of 2,6-diphenylphenol; this was successful resulting in the structural elucidation of a fully refined crystal structure of 2,6-diphenylphenol. The crystalline sponge {[(ZnI2)3(TPT)2].x(solvent)}n and its ZnBr2 variant were used to obtain crystal structures of the liquid agrochemical active ingredients metalaxyl-M and S-metolachlor. The encapsulation of three model compounds with similar chemical fragments to metalaxyl-M and S-metolachlor were also studied allowing for the effect of guest size on the position of the pores the guests occupy to be investigated. Additionally, the effect of changing the ZnX2 (X = I or Br) nodes of the host metal-organic framework on the pore positions the guest molecules prefer to occupy and the effect of increasing the incubation temperature on guest inclusion was also studied. Further to this, studies were performed into the use of alternative metal-organic frameworks as crystalline sponges. This work was performed with the aim of mitigating the limitations of the original crystalline sponge and increasing the range of compounds that can have their structures elucidated via the crystalline sponge method. Several novel guest inclusion complexes have been presented using the metal-organic frameworks NOTT-125 and RUM-2. This demonstrated the ability of these frameworks to successfully order and elucidate the structures of guest compounds. It was observed that the framework RUM-2 was capable of elucidating the structures of both hydrophilic and hydrophobic structures, expanding the scope of the crystalline sponge method to a larger range of potent guest molecules. Additionally, an analysis of the host-guest interactions formed was performed when using RUM-2 as a crystalline sponge. It was observed that stronger covalent host-guest interactions were formed with guest molecules containing Lewis basic functional groups. These bonds were observed to allow for increased guest occupancy and improve guest ordering in comparison to that observed when solely non-covalent interactions were formed. Furthermore, experiments were performed to test the applicability of RUM-2 to the structural elucidation of agrochemical active ingredients. The successful structural elucidation of the herbicide active ingredient molinate in addition to the successful encapsulation of metalaxyl-M into {[(ZnI2)3(TPT)2].x(solvent)}n and its ZnBr2 variant demonstrated the potential of the crystalline sponge method in the structural elucidation of hard to crystallise compounds in the research and development of new agrochemical products

Scale-dependent influence of pre-existing basement shear zones on rift faulting : a case study from NE Brazil

Rifting of continental crust initiates faults that are commonly influenced by pre-existing structures. We document newly identified faults cutting Precambrian units in the interior of the NE Brazilian margin to assess the effects of structural inheritance on both rift geometry and fault architecture. Stratigraphic and structural data indicate that the faults were active in the main phase of rifting of Gondwana. The influence of pre-existing structures on the Mesozoic rift faulting is scale dependent. Regionally, the faults trend parallel to subvertical, crustal-scale Brasiliano (c. 750–540 Ma) shear zones. Mylonitic foliations and broadly distributed low strain in the lower crust indicated by shear-wave splitting controlled the overall orientation and kinematics of the rift faults. However, outcrop observations of the faults show that at scales up to hundreds of metres, mylonitic foliations have little influence on fault architectures. Faults cross-cut shear zones and do not commonly utilize foliation planes as shear fractures. Instead, slip zones and fractures have a range of orientations that form acute angles to the local foliation orientation. This observation explains the range of focal mechanisms associated with seismicity that coincides with ancient shear zones in intra-continental areas

A Framework for Guiding Transformative Growth after School Shootings

For the last 20 years, gun violence has severely compromised safety, learning outcomes, social development, and psychological well-being in many high school communities. An emerging body of international research describes strategies developed to support students and staff members in the wake of school shootings. However, these protocols are typically designed to help administrators manage the immediate sequelae of these incidents, leaving survivors to handle the lasting consequences of their experiences on their own. This article presents a broad framework for facilitating long-term psychological growth that can be integrated into high school curricula. It is based on the complementary theories of Post-Traumatic Growth (PTG) and Transformative Learning (TL), which explain how positive psychological change can occur after a traumatic event disrupts a person’s assumptive worldview. The three segments of the TL process—questioning, exploring, and experimenting—facilitate PTG by transforming established beliefs into broader meaning perspectives that accommodate present realities. The framework below provides an organized approach to guiding high school students, staff, and communities through the full process of rebuilding global schemas after a shooting occurs. It can be implemented alongside existing crisis-response models, resulting in an expansion of their utility. Its guided-growth strategies can also be leveraged to reshape school culture and encourage collective action in the surrounding community, maximizing the possibility of positive worldview development

A Framework for Guiding Transformative Growth After High School Shootings

For the last 20 years, gun violence has severely compromised safety, learning outcomes, social development, and psychological well-being in many high school communities. An emerging body of international research describes strategies developed to support students and staff members in the wake of school shootings. However, these protocols are typically designed to help administrators manage the immediate sequelae of these incidents, leaving survivors to handle the lasting consequences of their experiences on their own. This article presents a broad framework for facilitating long-term psychological growth that can be integrated into high school curricula. It is based on the complementary theories of Post-Traumatic Growth (PTG) and Transformative Learning (TL), which explain how positive psychological change can occur after a traumatic event disrupts a person’s assumptive worldview. The three segments of the TL process—questioning, exploring, and experimenting—facilitate PTG by transforming established beliefs into broader meaning perspectives that accommodate present realities. The framework below provides an organized approach to guiding high school students, staff, and communities through the full process of rebuilding global schemas after a shooting occurs. It can be implemented alongside existing crisis-response models, resulting in an expansion of their utility. Its guided-growth strategies can also be leveraged to reshape school culture and encourage collective action in the surrounding community, maximizing the possibility of positive worldview development

Automated high accuracy, rapid beam hardening correction in X-Ray Computed Tomography of multi-mineral, heterogeneous core samples

X-ray Computed Tomography scanning is an innovative procedure that allows representing the internal structure of samples. Among its several purposes, X-ray CT is widely used for investigation of petrophysical properties of porous media. To provide accurate results, it is necessary to have high quality scan images, free of artefacts. One of the most problematic artefacts is beam hardening, which, in cylindrical shapes, increases the attenuation values with increasing distance from the centre. Until now, no automatic solution has been proposed for cylindrically-shaped cores that is both computationally feasible and applicable to all geological media. A new technique is here introduced for correcting beam hardening, using a linearization procedure of the beam hardening curve applied after the reconstruction process. We have developed an automated open source plug-in, running on ImageJ software, which does not require any a priori knowledge of the material, distance from the source or the scan conditions (current, energy), nor any segmentation of phases or calibration scan on phantom data. It is suitable for expert and non-expert use, alike. We have tested the technique on μCT scan images of a plastic rod, a sample of loose sand, several heterogeneous sandstone core samples (with near-cylindrical shapes), and finally, on an internal scan of a Berea sandstone core. The Berea core was also scanned using a medical X-ray CT scanner with a fan-beam geometry, as opposed to a cone beam geometry, showing that our algorithm is equally effective in both cases. Our correction technique successfully removes the beam hardening artefact in all cases, as well as removing the cupping effect common to internal scans. For a Berea Sandstone, with a porosity of 20%, porosity calculated using the corrected scan is 20.54%, which compares to a value of 14.24% using the software provided by the manufacturer

Case Studies and Theories of the Arms Race

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68522/2/10.1177_096701068601700212.pd

X-ray CT and multiphase flow characterization of a 'bio-grouted' sandstone core : the effect of dissolution on seal longevity

Microbially induced carbonate precipitation (MICP) is a novel method for controlling permeability in the subsurface with potential for sealing or reducing leakage from subsurface engineering works such as carbon sequestration reservoirs. The purpose of this research was to measure, at core scale, the change in reservoir permeability and capillary pressure due to MICP during seal formation, then to monitor the integrity of the seal when exposed to acidic groundwater capable of causing dissolution. The experiment was carried out with a Berea sandstone core mounted in a high pressure core holder within a medical X-ray CT scanner. Multiple full volume CT scans gave spatially resolved maps of the changing porosity and saturation states throughout the experiment. Porosity and permeability decreased with MICP whilst capillary pressure was increased. Dissolution restored much of the original porosity, but not permeability nor capillary pressure. This lead to the conclusion that injection pathways were coupled with carbonate precipitation hence preferential flow paths sealed first and transport of the dissolution fluid was limited. Provided a high enough reduction in permeability can be achieved over a substantial volume, MICP may prove to be a durable bio-grout, even in acidic environments such as a carbon sequestration reservoir

'Microbial mortar'- restoration of degraded marble structures with microbially induced carbonate precipitation

To evaluate a restoration strategy for highly degraded marble structures, microbially induced carbonate precipitation (MICP) has been employed to reduce porosity and permeability in a column filled with coarse crushed marble. A 3D X-ray tomography scan revealed the spatial variation in porosity throughout the column and tracer breakthrough curves, recorded at intervals during treatment, enabled derivation of core-scale fluid transport properties and their alteration by precipitating carbonate. Micro-continuum scale flow modelling based on the X-ray data indicated that treatment led to changes in the pore network structure with flow increasingly focused into a smaller number of faster flowing open channels

Micro-continuum modelling of injection strategies for microbially induced carbonate precipitation

Microbially induced carbonate precipitation is a promising technique for ground improvement. In order for MICP to progress from a lab-scale process to a commercially viable alternative ground improvement option, a combination of field-trials and field-scale modelling of the process is required. We present the results of a field-scale model in which differing injection strategies are evaluated and find that longer treatment times make more efficient use of reagents, but may come with higher operational costs, and that utilising multiple strains of bacteria with different reaction kinetics and transport properties may improve efficiency