Productive Efficiency in Water Usage: An Analysis of Differences among Farm Types and Sizes in Georgia

In Georgia, the price of irrigation water is equal to the cost of extraction, including pumping and diversion, storage, treatment, and delivery costs. These water-pricing conditions are repeated in locales around the world. In lieu of established water markets, water use and its efficient use are driven more by farm-level characteristics and management strategies than by the resource price. The purpose of the research presented herein is to examine what factors guide Georgia farmers’ water use decisions. Using data envelopment analysis (DEA) to calculate technical water use efficiency scores, a second step Tobit model is estimated to determine the effect of farm type and farm size. A farms’ use of conservation tillage or organic farming positively affected their water use efficiency, while farms of smaller size or solely owned were more inefficient in water use.technical/productive water use efficiency, organic agriculture, DEA, Production Economics, Productivity Analysis, Resource /Energy Economics and Policy,

Wet spinning fibres from imogolite and carbon nanotubes

As 1D materials with high intrinsic strength and stiffness, nanotubes are promising building blocks for the next generation of fibres in structural composites. This thesis explores wet spinning techniques for assembling macroscale fibres from nanotubes. Carbon nanotubes (CNTs) are an obvious target material to compete with commercial carbon fibres, based on their excellent intrinsic mechanical properties and low density, alongside high electrical conductivity for multifunctional applications. However, studying CNT materials is challenging due to their intrinsically high optical absorbance and low X-ray scattering cross-section, as well as the dispersity of typical feedstocks in both size and helicity. Imogolite nanotubes (INTs) are an inorganic analogue that offers an opportunity to observe the assembly of nanotubes into fibres using both polarised optical microscopy (POM) and X-ray scattering (XRS). In contrast to CNTs, INTs are optically transparent and can be synthesised at low temperature to provide feedstocks that are uniform in structure and diameter. In this work, the first known pure INT fibres have been produced and used to understand the nanotube wet spinning process. In situ POM demonstrated that in cylindrical spinnerets the spinning dope undergoes plug flow with inhomogeneous alignment due to the shear thinning nature of the solutions. The use of a tapered spinneret enables good alignment of the spinning dope, due to the induced extensional flow. Using this information, CNT fibres were spun from reduced CNT solutions and the wet spinning process was refined using a combination of in situ observation and statistical experimental design. The dissolution of negatively-charged CNTs (nanotubides) was examined both from a theoretical perspective and experimentally to identify the key conditions required to obtain homogeneous spinning dopes. The optimal dissolution depended upon both degree of charging and effective stirring. The optimised CNT dope was then wet spun using a variety of coagulating systems to identify the accessible process window and optimum parameters for spinning from these reactive charged solutions. Further improvement of the CNT fibre properties is predicted to arise through the use of higher aspect ratio CNT feedstocks. However, challenges still remain in the liquid phase processing of longer CNTs. In order to create CNT fibres competitive with commercial CFs, future research should focus on how to process these longer feedstocks following the guidance in this thesis.Open Acces

Consolidated fuel reprossing program: The implications of force reflection for teleoperation in space

Previous research on teleoperator force feedback is reviewed and results of a testing program which assessed the impact of force reflection on teleoperator task performance are reported. Force relection is a type of force feedback in which the forces acting on the remote portion of the teleoperator are displayed to the operator by back-driving the master controller. The testing program compared three force reflection levels: 4 to 1 (four units of force on the slave produce one unit of force at the master controller), 1 to 1, and infinity to 1 (no force reflection). Time required to complete tasks, rate of occurrence of errors, the maximum force applied to tasks components, and variability in forces applied to components during completion of representative remote handling tasks were used as dependent variables. Operators exhibited lower error rates, lower peak forces, and more consistent application of forces using force relection than they did without it. These data support the hypothesis that force reflection provides useful information for teleoperator users. The earlier literature and the results of the experiment are discussed in terms of their implications for space based teleoperator systems. The discussion described the impact of force reflection on task completion performance and task strategies, as suggested by the literature. It is important to understand the trade-offs involved in using telerobotic systems with and without force reflection

Realism in Bret Harte

Thesis (M.A.)--Boston Universit

Milton aspiring : belief, influence, and Shakespeare

Abstract: Over the last several hundred years, literary criticism has paid generous attention to the works of John Milton and his greatest and, in space and time, closest predecessor, William Shakespeare. However as Alwin Thaler observed almost a century ago, “strangely enough . . . it has neglected the relationships between them.” Exploring the literary, ideological, and political reasons for that neglect, this dissertation searches out the ways that Shakespeare influenced Milton and, more specifically, how that influence contributed to the young Milton’s self-fashioning of the poetic identity he desired for himself: to be the vates poet of the English people. The influence of Shakespeare on the young Milton exemplifies a certain version of imitation that G.W. Pigman III has termed “dissimulative,” expanding on common notions of influence, particularly when authors with seemingly disparate approaches to their art still draw from one another in a way that is intentionally difficult to detect, however powerful. Each of the four chapters offers a reading of one of Milton’s early poems alongside one or more germane works by Shakespeare never before been read in the context of Milton’s early poetic development. Chapter 1 explores the two authors’ competing metaphysical notions of time by reading Milton’s mid-winter birth poem, On the Morning of Christ’s Nativity, hereafter referred to as the Nativity Ode, alongside Shakespeare’s play set around the “Festival of the Epiphany,” Twelfth Night: Or, What You Will. Chapter 2 explores the two authors’ competing notions of language, how it works and what it should do, by reading Milton’s A Masque to be Presented at Ludlow Castle, hereafter referred to as Comus, alongside Love’s Labour’s Lost and Measure for Measure. Chapter 3 explores the young Milton’s notions of poetic fame, the proper social role of the poet, and opposing approaches to employing poetry as a means to immortality by reading Lycidas alongside a selection of Shakespeare’s sonnets. The final chapter states a never-before suggested claim about Milton’s early verses “On Shakespeare,” namely that the young poet’s work contains layers of irony: while praising and imitating, Milton is also obliquely criticizing his latest and greatest predecessor.Englis

A Theory of Cramer-Rao Bounds for Constrained Parametric Models

A simple expression for the Cram'er-Rao bound (CRB) is presented for the scenario of estimating parameters $\theta$ that are required to satisfy a differentiable constraint function $f(\theta)$. A proof of this constrained CRB (CCRB) is provided using the implicit function theorem, and the encompassing theory of the CCRB is proven in a similar manner. This theory includes connecting the CCRB to notions of identifiability of constrained parameters; the linear model under a linear constraint; the constrained maximum likelihood problem, it's asymptotic properties and the method of scoring with constraints; and hypothesis testing. The value of the tools developed in this theory are then presented in the communications context for the convolutive mixture model and the calibrated array model