A 43-GHz AlInAs/GaInAs/InP HEMT grid oscillator

A 36-element hybrid grid oscillator has been fabricated. The active devices are InP-based High Electron Mobility Transistors (HEMT's). The grid oscillates at 43 GHz with an effective radiated power of 200 mW. Measurements show the E and H-plane radiation patterns have side lobes 10 dB below the main beam. These results are a significant improvement over a previous millimeter-wave grid oscillator, which had a divided beam because of substrate mode

Rule Governed Variation in Elicited Narratives in Peruvian Sign Language (LSP)

Wordless books offer a single-source methodology for the crosslinguistic elicitation of both spoken and signed narratives (Chafe, 1974). Yet, Labov (1972), in Sociolinguistic Patterns, argued that the most natural narratives result when subjects are emotionally engaged in their own life stories. We added a twist to the traditional single-source elicitation using Mercer Mayer’s book, Frog, Where are you? (Slobin 2004, 2005), where Deaf subjects, tested in groups, saw each other’s recountings. They embellished each upon the other in a spirit of one-upmanship, rendering richer and more natural narratives with the feel of storytelling in a face-to face tradition. This poster presents the results of transcription (using Elán, an annotation software) and linguistic analysis of two excerpts from this group elicitation (n=4) compared with a single-subject elicitation of the same narrative. The group elicitation yielded a richer and more varied use of options (involving classifiers, Size and Shape Specifiers, role shift, affect marking, facial adverbs, and narrative perspective, including personification), yet worked within the same LSP grammatical constraints in terms of lexical choice, use of space, ordering of ground before figure, perspective, agreement, tense, syntax, and non-manual grammar marking). We present a comparative analysis of elicitation under these two conditions and argue for the group elicitation as a more natural and productive approach to single source elicitation

Modelling of quasi-optical arrays

A model for analyzing quasi-optical grid amplifiers based on a finite-element electromagnetic simulator is presented. This model is deduced from the simulation of the whole unit cell and takes into account mutual coupling effects. By using this model, the gain of a 10×10 grid amplifier has been accurately predicted. To further test the validity of the model three passive structures with different loads have been fabricated and tested using a new focused-beam network analyzer that we developed

Improving the Accuracy of Software-Based Energy Analysis for Residential Buildings

This presentation describes the basic components of software-based energy analysis for residential buildings, explores the concepts of 'error' and 'accuracy' when analysis predictions are compared to measured data, and explains how NREL is working to continuously improve the accuracy of energy analysis methods

Controlling uranyl oxo group interactions to group 14 elements using polypyrrolic Schiff-base macrocyclic ligands

Heterodinuclear uranyl/group 14 complexes of the aryl- and anthracenyl-linked Schiff-base macrocyclic ligands LMe and LA were synthesised by reaction of UO2(H2L) with M{N(SiMe3)2}2 (M = Ge, Sn, Pb). For complexes of the anthracenyl-linked ligand (LA) the group 14 metal sits out of the N4-donor plane by up to 0.7 Å resulting in relatively short M⋯OUO distances which decrease down the group; however, the solid state structures and IR spectroscopic analyses suggest little interaction occurs between the oxo and group 14 metal. In contrast, the smaller aryl-linked ligand (LMe) enforces greater interaction between the metals; only the PbII complex was cleanly accessible although this complex was relatively unstable in the presence of HN(SiMe3)2 and some organic oxidants. In this case, the equatorial coordination of pyridine-N-oxide causes a 0.08 Å elongation of the endo UO bond and a clear interaction of the uranyl ion with the Pb(II) cation in the second donor compartment

Seismic Performance Assessment of Reinforced Concrete Structures: Quantifying The Effects of Damage and Informal Construction

Earthquakes have led to extensive loss of human life, destruction of the built environment, displacement of residents from their homes, and high economic costs in many parts of the world. These impacts largely stem from building collapse and damage, and reinforced concrete (RC) structures are a significant contributor. The behavior of RC buildings in earthquakes is highly uncertain, particularly when a building has been damaged or built informally. The goal of this research is to develop improved assessment techniques of RC buildings that increase the understanding of the seismic performance of RC structures in order to improve community outcomes in major earthquakes. This dissertation is a compilation of two studies that each present a new methodology for assessing seismic performance. In each, the methodology is also exercised for a set of archetype structures. These frameworks employ nonlinear simulation models and computationally efficient analysis methods. In a post-earthquake environment, repair and demolition decision making play a significant role in community recovery. These decisions are made based on a number of factors, including the future seismic performance of buildings. The connection between the extent of damage---and how best to evaluate damage---and the change in performance is not well understood. Chapter 2 of this dissertation presents a new computationally-efficient framework for evaluating future seismic performance based on damage. This relationship is affected by building characteristics: short period buildings are more sensitive to damage and highly ductile buildings are capable of withstanding higher levels of damage. The framework and the findings in this study can be used in conjunction with component-level assessments and visual inspection to guide post-earthquake decision making about repair and demolition. Informally-constructed houses have had devastating consequences in recent earthquakes. Informally constructed homes are those that are built without explicit engineering design or code-compliance, and may be built with low-quality materials. Despite the ubiquity of this type of construction, few seismic performance assessments have been conducted. Chapter 3 presents a methodology for evaluating the collapse risk of informally-built RC houses. This framework is exercised for houses in Puerto Rico, where informal construction is prevalent. This work revealed which building components and characteristics are most critical for seismic safety. Open-ground-story houses are most vulnerable to collapse, but can be improved through improved column detailing or retrofit. One-story houses are generally safer than two-story houses, heavier buildings generate larger seismic forces on building components. Confined masonry construction is safer than infilled masonry. These findings are used to provide recommendations for homeowners, builders, and local organizations that will improve seismic safety. The methods outlined in this study can be applied more broadly to areas where informal construction is common and seismic hazard is high.</p

Uranyl to Uranium(IV) Conversion through Manipulation of Axial and Equatorial Ligands

The controlled manipulation of the axial oxo and equatorial halide ligands in the uranyl dipyrrin complex, UO2Cl(L), allows the uranyl reduction potential to be shifted by 1.53 V into the range accessible to naturally occurring reductants that are present during uranium remediation and storage processes. Abstraction of the equatorial halide ligand to form the uranyl cation causes a 780 mV positive shift in the UV/UIV reduction potential. Borane functionalization of the axial oxo groups causes the spontaneous homolysis of the equatorial U–Cl bond and a further 750 mV shift of this potential. The combined effect of chloride loss and borane coordination to the oxo groups allows reduction of UVI to UIV by H2 or other very mild reductants such as Cp*2Fe. The reduction with H2 is accompanied by a B–C bond cleavage process in the oxo-coordinated borane

Molecularly controlled epoxy network nanostructures

AbstractEpoxy thermosets continue to be used in a variety of coatings, adhesives, and structural composites. Nanostructural heterogeneities have been proposed to determine the physical properties of these materials, but the presence and origin of these features is disputed. Here, we combine nano-chemical imaging and nano-thermal analysis to establish a connection between internal crosslinking and the appearance of nanoscale chemical heterogeneities in epoxy resins. Deflection of an AFM probe is used as a local sensor to detect photothermal expansion in response to infrared excitation, and nanoscale lateral variations are detected in response to illumination at wavenumbers associated with crosslinking. Furthermore, these heterogeneous chemical features correspond to an increased range of local thermal transitions, and only arise within highly cross-linked resins; lightly cross-linked specimens are found to be homogeneous

Assessment of the U.S. Department of Energy's Home Energy Scoring Tool

The National Renewable Energy Laboratory (NREL) conducted a series of assessments of the U.S. Department of Energy's (DOE) proposed Home Energy Scoring Tool (HEST). This report is an assessment of the 4/27/2012 release of HEST. Predictions of electric and natural gas consumption were compared with weather-normalized utility billing data for a mixture of newer and older homes located in Oregon, Wisconsin, Minnesota, North Carolina and Texas