6,215 research outputs found
Maintaining the Status Quo: Recommendations for Preserving Public Argument in Parliamentary Debate
Accompanied by praise and criticism, the growth of parliamentary debate in recent years has been exponential. As Robert Trapp, current President of the National Parliamentary Debate Association points out in his May 28, 1997 letter to the membership of the NPDA, (f)rom 1994 to 1997, our Championship Tournament has grown from just over fifty teams to almost four times as many. Measured in numerical terms, the NPDA is a healthy infant. Given this growth, a discussion of the future of parliamentary debate seems appropriate.
Regardless of one\u27s perspective of what parliamentary debate is, much has been written about what parliamentary debate should be. In 1992 Epstein discussed the dissatisfaction with various forms of intercollegiate debate, and suggested that [o]ne proposed alternative to this rift in the debate community is the development of parliamentary debate under the auspices of the American Parliamentary Debate Association (APDA) and the Western States Parliamentary Debate Association (WSPDA). Johnson continued the discussion in 1994 by expressing concern that parliamentary debate may take the same path as CEDA, which is taking the same path which NDT took several years ago ... by adopting increasingly specialized styles, vocabularies and judging criteria.
These perspectives, and the manifold others expressed both formally and informally, serve to provide direction for parliamentary debate in relation to other alternatives available. While this is certainly a worthwhile undertaking, I propose that we make an effort to define parliamentary debate by what it is, rather than what it is not. To that end, I subscribe to Trapp\u27s conceptualization of parliamentary debate as a forum for public argument, and will offer practical recommendations that I believe will further this conception
Physical aging and solvent effects on the fracture of LaRC-TPI adhesives
When amorphous materials are quenched below their glass transition temperature, excess enthalpy is trapped in the glassy material because the viscosity is too great to allow the material to remain in volumetric equilibrium. Over time, this excess free volume is reduced as the material slowly approaches its equilibrium configuration. This process, known as physical aging, leads to substantial changes in the constitutive behavior of polymers, as has been widely discussed in the literature. Less is known about the effects of this physical aging process on fracture and fatigue properties of aged materials. The original goal of the summer was to investigate the effects of physical aging on the fracture and fatigue behavior of LaRC-TPI, a thermoplastic polyimide developed at NASA-Langley. Preliminary results are reported, although a lack of equipment availability prevented completion of this task. In the process of making specimens, the current LaRC-TPI was observed to be extremely susceptible to environmental stress cracking. A study of the unique failure patterns resulting from this degradation process in bonded joints was conducted and is also reported herein
Effects of Secondary Air Injection Upon the Fluidization Characteristics of the Lower Stage in a Two-Stage, Variable-Area Fluidized Bed Riser
A transparent scale model of a two-stage fluidized bed coal dryer with a small diameter lower stage and a large diameter upper stage, separated by a conical transition zone with secondary air injection ports, has been constructed to study the effects of secondary air injection upon the fluidization characteristics of the lower riser stage. The superficial velocity of the lower stage of the riser was held constant within the turbulent fluidization regime while the superficial gas velocity in the upper riser stage was varied by changing the volumetric flow rates of air introduced between the upper and lower riser stages. Through examination of time series pressure data via standard deviation, autocorrelation, spectral density plots and visual observation of dense bed height, it becomes apparent that secondary air injection has a dominant effect upon the fluidization characteristics below the injection location, leading to a transition from a dense to a dilute bed
Micro-CT Image-Derived Metrics Quantify Arterial Wall Distensibility Reduction in a Rat Model of Pulmonary Hypertension
We developed methods to quantify arterial structural and mechanical properties in excised rat lungs and applied them to investigate the distensibility decrease accompanying chronic hypoxia-induced pulmonary hypertension. Lungs of control and hypertensive (three weeks 11% O2) animals were excised and a contrast agent introduced before micro-CT imaging with a special purpose scanner. For each lung, four 3D image data sets were obtained, each at a different intra-arterial contrast agent pressure. Vessel segment diameters and lengths were measured at all levels in the arterial tree hierarchy, and these data used to generate features sensitive to distensibility changes. Results indicate that measurements obtained from 3D micro-CT images can be used to quantify vessel biomechanical properties in this rat model of pulmonary hypertension and that distensibility is reduced by exposure to chronic hypoxia. Mechanical properties can be assessed in a localized fashion and quantified in a spatially-resolved way or as a single parameter describing the tree as a whole. Micro-CT is a nondestructive way to rapidly assess structural and mechanical properties of arteries in small animal organs maintained in a physiological state. Quantitative features measured by this method may provide valuable insights into the mechanisms causing the elevated pressures in pulmonary hypertension of differing etiologies and should become increasingly valuable tools in the study of complex phenotypes in small-animal models of important diseases such as hypertension
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