Selling Solar: Financing Household Solar Energy in the Developing World

Based on value chain analyses of case studies, outlines the issues and challenges for developing a solar energy industry, with a focus on the need for a financing infrastructure that serves purchasers, manufacturers, distributors, and investors

In-shock Cooling in Numerical Simulations

We model a one-dimensional shock-tube using smoothed particle hydrodynamics and investigate the consequences of having finite shock-width in numerical simulations. We investigate the cooling of gas during passage through the shock for different cooling regimes. For a shock temperature of 10^5K, the maximum temperature of the gas is much reduced and the cooling time was reduced by a factor of 2. At lower temperatures, we are especially interested in the production of molecular Hydrogen and so we follow the ionization level and H_2 abundance across the shock. This regime is particularly relevent to simulations of primordial galaxy formation for halos in which the virial temperature of the galaxy is sufficiently high to partially re-ionize the gas. The effect of in-shock cooling is substantial: the maximum temperature the gas reaches compared to the theoretical temperature was found to vary between 0.15 and 0.81 for the simulations performed. The downstream ionization level is reduced from the theoretical level by a factor of between 2.4 and 12.5, and the resulting H_2 abundance was found to be reduced to a fraction of 0.45 to 0.74 of its theoretical value. At temperatures above 10^5K, radiative shocks are unstable and will oscillate. We reproduce these oscillations and find good agreement with the previous work of Chevalier and Imamura (1982), and Imamura, Wolff and Durisen (1984). The effect of in-shock cooling in such shocks is difficult to quantify, but is undoubtedly present.Comment: 8 pages, LaTeX, 7 figure

Calibration Modeling Methodology to Optimize Performance for Low Range Applications

Calibration is a vital process in characterizing the performance of an instrument in an application environment and seeks to obtain acceptable accuracy over the entire design range. Often, project requirements specify a maximum total measurement uncertainty, expressed as a percent of full-scale. However in some applications, we seek to obtain enhanced performance at the low range, therefore expressing the accuracy as a percent of reading should be considered as a modeling strategy. For example, it is common to desire to use a force balance in multiple facilities or regimes, often well below its designed full-scale capacity. This paper presents a general statistical methodology for optimizing calibration mathematical models based on a percent of reading accuracy requirement, which has broad application in all types of transducer applications where low range performance is required. A case study illustrates the proposed methodology for the Mars Entry Atmospheric Data System that employs seven strain-gage based pressure transducers mounted on the heatshield of the Mars Science Laboratory mission

Automatic Pulmonary Nodule Detection in CT Scans Using Convolutional Neural Networks Based on Maximum Intensity Projection

Accurate pulmonary nodule detection is a crucial step in lung cancer screening. Computer-aided detection (CAD) systems are not routinely used by radiologists for pulmonary nodule detection in clinical practice despite their potential benefits. Maximum intensity projection (MIP) images improve the detection of pulmonary nodules in radiological evaluation with computed tomography (CT) scans. Inspired by the clinical methodology of radiologists, we aim to explore the feasibility of applying MIP images to improve the effectiveness of automatic lung nodule detection using convolutional neural networks (CNNs). We propose a CNN-based approach that takes MIP images of different slab thicknesses (5 mm, 10 mm, 15 mm) and 1 mm axial section slices as input. Such an approach augments the two-dimensional (2-D) CT slice images with more representative spatial information that helps discriminate nodules from vessels through their morphologies. Our proposed method achieves sensitivity of 92.67% with 1 false positive per scan and sensitivity of 94.19% with 2 false positives per scan for lung nodule detection on 888 scans in the LIDC-IDRI dataset. The use of thick MIP images helps the detection of small pulmonary nodules (3 mm-10 mm) and results in fewer false positives. Experimental results show that utilizing MIP images can increase the sensitivity and lower the number of false positives, which demonstrates the effectiveness and significance of the proposed MIP-based CNNs framework for automatic pulmonary nodule detection in CT scans. The proposed method also shows the potential that CNNs could gain benefits for nodule detection by combining the clinical procedure.Comment: Submitted to IEEE TM

Interim report on the analysis of the microwave power module

The results of a traveling wave tube multistage depressed collector (TWT-MDC) design study in support of the DARPA/DoD Microwave Power Module (MPM) Program are described. The study stressed the MDC as a key element in obtaining the required high overall efficiencies in the MPM application. The results showed that an efficient MDC, utilizing conventional design and fabrication techniques can be designed for the first generation MPM TWT, which permits a package one wavelength thick (.66 in. at 18 GHz). The overall TWT efficiency goal of 40 percent for electronic countermeasure (ECM) applications appears to be readily achievable. However, the 50 percent goal for radar applications presents a considerable challenge

Neuronal cell proliferation and ocular enlargement in black moor goldfish

The mechanisms that control cell proliferation in the developing nervous system are not well understood. In larval and adult goldfish addition of new retinal neurons continues as the eye grows, but the factors that modulate the rate of cell proliferation are unknown. The eyes of Black Moors grow excessively during postembryonic life, probably as a direct result of abnormally elevated intraocular pressure. Ocular growth must be partly autonomous in Black Moors because in some individuals the two eyes are very different in size. To determine whether cell proliferation and neuronal cell number in the retina were correlated with size of the eye, we counted dividing neuronal progenitor cells (rod precursors) and mature retinal neurons (ganglion cells) in the retinas of ocularly asymmetric fish. Rod Precursors, which are scattered across the retina in the outer nuclear layer, were labeled with 3 H-thymidine and counted on histological sections processed for autoradiography. Ganglion cells were counted in retinal whole mounts. We found that the total population of dividing rod precursors and the total number of ganglion cells were systematically greater in the large eye compared to the small eye of individual fish. We conclude that control of the rate of neuronal proliferation in the teleost retina is intrinsic to the eye and is probably regulated by the same factors that control ocular growth.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50040/1/902760207_ftp.pd

The elimination of the influence of ambient environmental effects on the structure of `inert\u27 polymers

The construction and use of a vacuum chamber suitable for conventional X-ray diffraction has revealed the influence of the ambient environment, including moisture, on the bulk structure of very thin polymer films. It is concluded that studies of thin film organic systems, even those thought not to be perturbed by ambient water vapor and other contaminants, may benefit from undertaking some studies in such small sample vacuum chambers