Overview and Uncertainty Analysis for an Irrigation Flow Measurement Facility

Accurate flow measurement is critical for modern water resource management. At the irrigation district level, instantaneous flow rates must be well-measured at key bifurcation points to reliably meet downstream demand in open channel systems while also minimizing diversions. Furthermore, good flow measurement at each delivery point is a pre-requisite for successful volumetric water billing. Accuracy and repeatability are important characteristics of good flow measurement. Maximizing these traits requires periodic calibration to a common standard. This paper presents an overview of calibration efforts and the engineering background behind an active flow measurement facility at the Irrigation Training and Research Center at California Polytechnic State University, San Luis Obispo (Cal Poly). The facility is fitted with two major flow measurement devices, a gravimetric weighing tank and a volumetric tank. Although both are used for comparison, verification, and calibration of closed pipe and open channel flow measurement devices, this report will focus on an uncertainty analysis for the gravimetric weighing tank

Modernizing Aging Pipe Infrastructure in Irrigation Districts

Many irrigation and water districts in California convey water through aging concrete pipelines. In addition to huge problems with leaks and failures, districts also struggle to provide turnout deliveries with more flexible schedules. This paper discusses the problems that are encountered, and various approaches that have been or can be used. The specific pipeline designs that are discussed in this paper are generally gravity flow, flowing downhill from a canal. Most of these pipelines were originally installed under the assumptions that farmers would need high flows at low pressures for surface irrigation

Conditioning of Velocity Profiles in Pipelines

This paper reports on the testing of a relatively simple flow conditioner for pipelines. This research found that a pipeline velocity flow conditioner that is constructed with an internal cone, having an inside diameter of 80 percent of the pipeline ID, provided the best results. It provided good velocity conditioning at a distance of two diameters downstream of an obstruction. The minor loss is equal to the velocity head of the flow in the original pipeline diameter

Decoding visual information from high-density diffuse optical tomography neuroimaging data

BACKGROUND: Neural decoding could be useful in many ways, from serving as a neuroscience research tool to providing a means of augmented communication for patients with neurological conditions. However, applications of decoding are currently constrained by the limitations of traditional neuroimaging modalities. Electrocorticography requires invasive neurosurgery, magnetic resonance imaging (MRI) is too cumbersome for uses like daily communication, and alternatives like functional near-infrared spectroscopy (fNIRS) offer poor image quality. High-density diffuse optical tomography (HD-DOT) is an emerging modality that uses denser optode arrays than fNIRS to combine logistical advantages of optical neuroimaging with enhanced image quality. Despite the resulting promise of HD-DOT for facilitating field applications of neuroimaging, decoding of brain activity as measured by HD-DOT has yet to be evaluated. OBJECTIVE: To assess the feasibility and performance of decoding with HD-DOT in visual cortex. METHODS AND RESULTS: To establish the feasibility of decoding at the single-trial level with HD-DOT, a template matching strategy was used to decode visual stimulus position. A receiver operating characteristic (ROC) analysis was used to quantify the sensitivity, specificity, and reproducibility of binary visual decoding. Mean areas under the curve (AUCs) greater than 0.97 across 10 imaging sessions in a highly sampled participant were observed. ROC analyses of decoding across 5 participants established both reproducibility in multiple individuals and the feasibility of inter-individual decoding (mean AUCs \u3e 0.7), although decoding performance varied between individuals. Phase-encoded checkerboard stimuli were used to assess more complex, non-binary decoding with HD-DOT. Across 3 highly sampled participants, the phase of a 60° wide checkerboard wedge rotating 10° per second through 360° was decoded with a within-participant error of 25.8±24.7°. Decoding between participants was also feasible based on permutation-based significance testing. CONCLUSIONS: Visual stimulus information can be decoded accurately, reproducibly, and across a range of detail (for both binary and non-binary outcomes) at the single-trial level (without needing to block-average test data) using HD-DOT data. These results lay the foundation for future studies of more complex decoding with HD-DOT and applications in clinical populations

Development of Software for Characterization of Local Atomic Structures in Amorphous Metals Via Weighted Voronoi Diagrams

Mentor: Kenneth F. Kelton From the Washington University Undergraduate Research Digest: WUURD, Volume 8, Issue 1, Fall 2012. Published by the Office of Undergraduate Research, Joy Zalis Kiefer Director of Undergraduate Research and Assistant Dean in the College of Arts & Sciences

Human Brain Imaging and Decoding with Ultra-High-Density Diffuse Optical Tomography

Modern brain imaging modalities, particularly functional MRI (fMRI), have enabled dramatic advances in cognitive neuroscience, human brain mapping, and neural decoding. For example, in the last decade, fMRI has decoded the identities and categories of thousands of images being viewed by human participants and has even reconstructed visual scenes and sentences. However, standard fMRI employs large, non-portable equipment that cannot be used at the bedside, cannot image many patients with metal implants, is difficult in young children, is not naturalistic, and is impractical for chronic brain-computer interface (BCI) in patients with completely locked-in syndrome whose paralysis prevents communication via ordinary means. Functional near-infrared spectroscopy (fNIRS) images blood dynamics non-invasively, like fMRI, and has potential to address many fMRI limitations. While fNIRS traditionally used sparse source-detector arrays and suffered from poor resolution and distorted point-spread functions, newer high-density diffuse optical tomography (HD-DOT) systems provide higher image quality and a superior surrogate to fMRI at the brain surface. Moving from sparse 30-mm-spaced arrays, with single-distance measurements, to high-density 13-mm-spaced arrays, with multiple-distance measurements, provides better brain specificity, improved resolution, and higher contrast-to-noise ratio. In this dissertation, I first performed simulations indicating that further reducing inter-optode spacing to 6.5 mm (ultra-high density) would further improve image quality and noise-resolution tradeoff. To realize these improvements, I then designed, constructed, and validated an ultra-high-density DOT system, which imaged stimulus-evoked activations with higher spatial resolution and decoded visual stimulus position with lower error than conventional HD-DOT. Finally, I adapted a motion-energy encoding model from previous successful fMRI studies and decoded the identities of up to 40 movie clips outside the decoder’s training set using HD-DOT. Many of the powerful fMRI decoding paradigms leverage these types of encoding models that predict how the brain responds to a generalizable set of stimulus features, yet previous fNIRS and DOT decoding studies were limited to template-based decoding or simpler methods and thus were not able to decode outside the training stimuli. This dissertation research surmounts that limitation and provides a roadmap for translating powerful fMRI decoding capabilities into naturalistic settings with HD-DOT, especially as other fully wearable HD-DOT systems continue emerging

Structural Characterization of Amorphous Cu46Zr54 using Molecular Dynamics Simulations, Reverse-Monte Carlo Simulations, and Weighted Voronoi Diagrams

Mentor: Kenneth Kelton From the Washington University Undergraduate Research Digest: WUURD, Volume 9, Issue 1, Fall 2013. Published by the Office of Undergraduate Research. Joy Zalis Kiefer Director of Undergraduate Research and Assistant Dean in the College of Arts & Sciences

Structural Characterization of Amorphous Cu46Zr54 Using Molecular Dynamics Simulations, Reverse-Monte Carlo Simulations, and Weighted Voronoi Diagrams

From the Washington University Senior Honors Thesis Abstracts (WUSHTA), Volume 6, Spring 2014. Published by the Office of Undergraduate Research. Joy Zalis Kiefer, Director of Undergraduate Research and Associate Dean in the College of Arts & Sciences; Jane Green and Stacy Ross, Editors; Kristin G. Sobotka, Undergraduate Research Coordinator. Mentor: Kenneth F. Kelto

Water Hammer Protection for Pumped Turnouts on Aging Pipelines

Water hammer in an irrigation district pipeline is typically caused by sudden changes in turnout flow rates. A sudden shutoff of a booster pump, or a rapid closure of a turnout valve, can potentially cause surge damage. The problem occurs if the pressure exceeds the pressure rating of the pipeline. As pipes age, their pressure rating typically declines. This report describes three different solutions that utilize a combination of these techniques/devices to provide district pipeline protection from water hammer