Three dimensional representation and analysis of individual bead and packed bed scale chromatography using X-ray computed tomography and focused ion beam microscopy

Understanding the detailed, internal geometry of chromatography bead and packed bed structure remains a challenge, which is addressed in this thesis by using tomographic techniques to both visualise and quantify microstructural characteristics at both scales. Two main approaches were investigated for the purposes of producing accurate representations: X-ray computed tomography and focused ion beam microscopy, both providing high-resolution capability for imaging geometric features, enabling comparison between material types and techniques when considering suitability for chromatography structural research. At the bead scale, X-ray computed tomography and focused ion beam microscopy were used for imaging and comparison of the three bead types, with optimal cubic pixel sizes of 32nm and 15nm achieved respectively. Despite the superior resolution attainable for focused ion beam microscopy, drawbacks of intensive preparation requirements and the necessity for physical slicing and thus destruction highlighted that pixel dimensions were not the only consideration for sub-micron tomographic imaging. Tortuosity, which impacts important performance metrics such as transfer rates, was found to be below 2 in all cases due to the high porosities exhibited, with average pore size greatly influenced by the overall resolution. At the packed bed scale, X-ray CT was the sole technique selected using two different systems, with one system only capable of sufficiently imaging the harder ceramic samples, albeit achieving an overall superior pixel size of 2.7µm. Optimisation of X-ray conditions was required for each different material and corresponding equipment in order to achieve 3D representations of sufficient quality; to both visually display the packed bed structure in addition to providing the capability of quantifying key metrics relating to chromatography geometries and thus performance. Porosity readings of approximately 35% were in agreement with values obtained using established techniques and values, with radial discrepancies identified that were expected due to wall-effects impacting packing densities. Two industrially relevant chromatography processing considerations were examined using X-ray CT: fouling and packed bed compression. Both scales were investigated for fouling, with individual beads imaged between cycles to measure the change in simulated diffusivity due to foulant impregnation. Compression of packed beds was imaged before, during and after excessive flow through columns, where visual and quantitative changes to aspects such as simulated permeability were compared between states. The values obtained in both of these studies based upon real systems were compared to changes in porosity and tortuosity factor by applying erosion-dilation to structure in an original state

Design and Code Optimization for Systems with Next-generation Racetrack Memories

With the rise of computationally expensive application domains such as machine learning, genomics, and fluids simulation, the quest for performance and energy-efficient computing has gained unprecedented momentum. The significant increase in computing and memory devices in modern systems has resulted in an unsustainable surge in energy consumption, a substantial portion of which is attributed to the memory system. The scaling of conventional memory technologies and their suitability for the next-generation system is also questionable. This has led to the emergence and rise of nonvolatile memory ( NVM ) technologies. Today, in different development stages, several NVM technologies are competing for their rapid access to the market. Racetrack memory ( RTM ) is one such nonvolatile memory technology that promises SRAM -comparable latency, reduced energy consumption, and unprecedented density compared to other technologies. However, racetrack memory ( RTM ) is sequential in nature, i.e., data in an RTM cell needs to be shifted to an access port before it can be accessed. These shift operations incur performance and energy penalties. An ideal RTM , requiring at most one shift per access, can easily outperform SRAM . However, in the worst-cast shifting scenario, RTM can be an order of magnitude slower than SRAM . This thesis presents an overview of the RTM device physics, its evolution, strengths and challenges, and its application in the memory subsystem. We develop tools that allow the programmability and modeling of RTM -based systems. For shifts minimization, we propose a set of techniques including optimal, near-optimal, and evolutionary algorithms for efficient scalar and instruction placement in RTMs . For array accesses, we explore schedule and layout transformations that eliminate the longer overhead shifts in RTMs . We present an automatic compilation framework that analyzes static control flow programs and transforms the loop traversal order and memory layout to maximize accesses to consecutive RTM locations and minimize shifts. We develop a simulation framework called RTSim that models various RTM parameters and enables accurate architectural level simulation. Finally, to demonstrate the RTM potential in non-Von-Neumann in-memory computing paradigms, we exploit its device attributes to implement logic and arithmetic operations. As a concrete use-case, we implement an entire hyperdimensional computing framework in RTM to accelerate the language recognition problem. Our evaluation shows considerable performance and energy improvements compared to conventional Von-Neumann models and state-of-the-art accelerators

Spatial Synthesis: Centrality and Hierarchy

There is a file containing the full book in pdf format. Animated figures are attached within the pdf. To access them, download the pdf and open it will a full pdf reader, such as Adobe Acrobat. There are three zipped files with interactive maps (Imaps) that support material in Chapter 6. Download these, unzip them, and then launch the map by opening the file, index.html. There are single chapter/section files, presented as pdfs. Again, animated images are attached within the files. Download them and open using a full pdf reader to see the attachments. Finally, there is an older, partial, zipped file of much of the book, which is only of limited utility.First in a set of volumes on spatial synthesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58264/2/Spatial Synthesis.ziphttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/3/SpatialSynthesisVol1Book1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/4/06_SSFig6.5a_imap6.1.ziphttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/5/06_SSFig6.5b_imap6.2.ziphttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/6/06_SSFig6.5c_imap6.3.ziphttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/7/00_SS_CoverFull.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/8/0_SSIntroductionFull.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/9/01_SSChapter 1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/10/02_SSChapter 2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/11/03_SSChapter 3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/12/04_SSChapter 4.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/13/05_SSChapter 5.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/14/06_SSChapter 6.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/15/07_SSBibliography.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/16/08_SSAppendicesFull.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/17/09_SSImaps.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/58264/18/10_SSvirtualreality.pdfDescription of SpatialSynthesisVol1Book1.pdf : Book with animated attachmentsDescription of 06_SSFig6.5a_imap6.1.zip : Imap 6.1Description of 06_SSFig6.5b_imap6.2.zip : Imap 6.2Description of 06_SSFig6.5c_imap6.3.zip : Imap 6.3Description of 00_SS_CoverFull.pdf : Cover/frontmatterDescription of 0_SSIntroductionFull.pdf : Introduction and associated linksDescription of 01_SSChapter 1.pdf : Chapter 1Description of 02_SSChapter 2.pdf : Chapter 2Description of 03_SSChapter 3.pdf : Chapter 3Description of 04_SSChapter 4.pdf : Chapter 4Description of 05_SSChapter 5.pdf : Chapter 5Description of 06_SSChapter 6.pdf : Chapter 6Description of 07_SSBibliography.pdf : BibliographyDescription of 08_SSAppendicesFull.pdf : Appendices overviewDescription of 09_SSImaps.pdf : Appendix ImapsDescription of 10_SSvirtualreality.pdf : Appendix virtual realit

An Introduction to Particle Physics and the Standard Model

An Introduction to the Standard Model of Particle Physics familiarizes readers with what is considered tested and accepted and in so doing, gives them a grounding in particle physics in general. Whenever possible, Dr. Mann takes an historical approach showing how the model is linked to the physics that most of us have learned in less challenging a

NASA thesaurus. Volume 2: Access vocabulary

The access vocabulary, which is essentially a permuted index, provides access to any word or number in authorized postable and nonpostable terms. Additional entries include postable and nonpostable terms, other word entries and pseudo-multiword terms that are permutations of words that contain words within words. The access vocabulary contains almost 42,000 entries that give increased access to the hierarchies in Volume 1 - Hierarchical Listing