Adapting to Drought in the Colorado River Basin: A Case Study of Indigenous Voices in Water Management

Senior Project submitted to The Division of Social Studies of Bard Colleg

Nearly Monodispersion CoSm Alloy Nanoparticles Formed by an In-situ Rapid Cooling and Passivating Microfluidic Process

An in siturapid cooling and passivating microfluidic processhas been developed for the synthesis of nearly monodispersed cobalt samarium nanoparticles (NPs) with tunable crystal structures and surface properties. This process involves promoting the nucleation and growth of NPs at an elevated temperature and rapidly quenching the NP colloids in a solution containing a passivating reagent at a reduced temperature. We have shown that Cobalt samarium NPs having amorphous crystal structures and a thin passivating layer can be synthesized with uniform nonspherical shapes and size of about 4.8 nm. The amorphous CoSm NPs in our study have blocking temperature near 40 K and average coercivity of 225 Oe at 10 K. The NPs also exhibit high anisotropic magnetic properties with a wasp-waist hysteresis loop and a bias shift of coercivity due to the shape anisotropy and the exchange coupling between the core and the thin oxidized surface layer

Continuous microfluidic synthesis of zirconium-based UiO-67 using a coiled flow invertor reactor

Metal-organic frameworks (MOFs), particularly Zirconium based, have a wide variety of potential applications, such as catalysis and separation. However, these are held back by traditionally only being synthesised in long batch reactions, which causes the process to be expensive and limit the amount of reaction control available, leading to potential batch to batch variation in the products, such as particle size distributions. Microfluidics allows for batch reactions to be performed with enhanced mass/heat transfer, with the coiled flow inverter reactor (CFIR) setup narrowing the residence time distribution, which is key in controlling the particle size and crystallinity. In this work, a Zirconium based MOF, UiO-67, has been synthesised continuously using a microfluidic CFIR, which has allowed for the product to be formed in 30 min, a fraction of the traditional batch heating time of 24 h. The microfluidicially synthesised UiO-67 is also smaller product with a narrower particle size distribution (≈200 nm to ≈400 nm) than its batch counterpart (~500 nm to over 3 µm)

In Situ Growth and Characterization of Metal Oxide Nanoparticles within Polyelectrolyte Membranes

This study describes a novel approach for the inâ situ synthesis of metal oxideâ polyelectrolyte nanocomposites formed via impregnation of hydrated polyelectrolyte films with binary water/alcohol solutions of metal salts and consecutive reactions that convert metal cations into oxide nanoparticles embedded within the polymer matrix. The method is demonstrated drawing on the example of Nafion membranes and a variety of metal oxides with an emphasis placed on zinc oxide. The inâ situ formation of nanoparticles is controlled by changing the solvent composition and conditions of synthesis that for the first time allows one to tailor not only the size, but also the nanoparticle shape, giving a preference to growth of a particular crystal facet. The highâ resolution TEM, SEM/EDX, UVâ vis and XRD studies confirmed the homogeneous distribution of crystalline nanoparticles of circa 4â nm and their aggregates of 10â 20â nm. The produced nanocomposite films are flexible, mechanically robust and have a potential to be employed in sensing, optoelectronics and catalysis.The factors governing the inâ situ growth of metal oxide nanoparticles within a selfâ segregated polyelectrolyte membrane, Nafion, are investigated. By varying the binary water/alcohol solvent mixture the size, shape, and exposed crystal facets can be tailored.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137385/1/anie201606178.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137385/2/anie201606178_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137385/3/anie201606178-sup-0001-misc_information.pd

Nucleic Acid-based Detection of Bacterial Pathogens Using Integrated Microfluidic Platform Systems

The advent of nucleic acid-based pathogen detection methods offers increased sensitivity and specificity over traditional microbiological techniques, driving the development of portable, integrated biosensors. The miniaturization and automation of integrated detection systems presents a significant advantage for rapid, portable field-based testing. In this review, we highlight current developments and directions in nucleic acid-based micro total analysis systems for the detection of bacterial pathogens. Recent progress in the miniaturization of microfluidic processing steps for cell capture, DNA extraction and purification, polymerase chain reaction, and product detection are detailed. Discussions include strategies and challenges for implementation of an integrated portable platform

Polarity in ZnO nanowires: A critical issue for piezotronic and piezoelectric devices

The polar and piezoelectric nature of the wurtzite structure of ZnO nanowires with a high aspect ratio at nanoscale dimensions is of high interest for piezotronic and piezoelectric devices, but a number of issues related to polarity are still open and deserve a particular attention. In this context, chemical bath deposition offers a unique opportunity to select the O- or Zn-polarity of the resultant nanowires and is further compatible with the fabrication processes of flexible devices. The control and use of the polarity in ZnO nanowires grown by chemical bath deposition opens a new way to greatly enhance the performance of the related piezotronic and piezoelectric devices. However, polarity as an additional tunable parameter should be considered with care because it has a strong influence on many processes and properties. The present review is intended to report the most important consequences related to the polarity in ZnO nanowires for piezotronic and piezoelectric devices. After introducing the basic principles involving crystal polarity in ZnO, a special emphasis is placed on the effects of polarity on the nucleation and growth mechanisms of ZnO nanowires using chemical bath deposition, defect incorporation and doping, electrical contacts and device properties

Electrokinetic transport and fluid motion in microanalytical electrolyte systems

Electrically-driven separation schemes, such as zone electrophoresis (ZE), isotachophoresis (ITP) and isoelectric focusing (IEF), are used profoundly to fractionate mixtures of charged compounds for preparative and particularly analytical applications. Inherent to the separation process is the development of local variations in the electrical conductivity, pH, electric field, etc. One-dimensional, quantitative descriptions of the spatio-temporal evolution of these variations, and their role in the separation process, have been developed over the past two decades. These descriptions lend significant insight into the electromigrational behavior of analytes and buffer components. Nevertheless, because they are one-dimensional, such descriptions omit important effects of electrokinetic fluid motion. The fluid motion arises naturally in the context of the separation scheme, and affects the evolving spatial gradients associated with the separation process. One-dimensional simulations have also been plagued by numerical limitations associated with advection-dominant transport in regions of sharp concentration gradients. In this dissertation, the numerical difficulties are resolved, and a general two-dimensional model of electrokinetic separations is presented. Because the balance laws account for coupling of the velocity field to the ion transport, a variety of processes important to both microfluidic manipulations and analytical separations can be considered. High-ionic strength electroosmotic pumping and field-amplified sample stacking are examined in detail. It is demonstrated that unsteady fluid eddies disperse the gradients in the field variables, and this limits the efficacy of microanalysis processes. Scaling arguments suggest that, at least for simple geometries, approximate solutions to the general model are possible. Semi-analytic approximations are constructed for the fluid velocity v and electric field E, and the parameter space over which they apply is defined. These approximations reduce simulation times by about two thirds, and provide general information on the dominant physics in microanalysis processes. The scale analysis and simulation results demonstrate that although cross-sectional conductivity gradients meet or exceed those in the axial direction, the electric field is essentially unidirectional. Also, at sufficiently high electric field strengths (ca. several hundred V/cm), nonlinear electrohydrodynamic stresses begin to influence the fluid motion. Finally, if the electrical stresses are negligible, the semi-analytic solutions for v and E permit 1-D macrotransport representations of the solute transport. Effective 1-D simulations yield cross-sectionally averaged values for the field variables in orders of magnitude less simulation time than 2-D simulations

Miniature spatial transcriptomics for studying parasite-endosymbiont relationships at the micro scale

Processed gene count matrices, related metadata, corresponding ST tissue H&E microscopy images, and 3D model HTML files generated in the study "Miniature spatial transcriptomics for studying parasite-endosymbiont relationships at the micro scale"THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV