Outsourcing for New Technology Adoption

Leveraging the advantages of outsourcing in the area of new technology adoption depends not only on selecting the right vendor, but on developing a comprehensive strategy that assesses the internal technology environment and meets organizational needs.     

Z-source inverter for motor drives

This paper presents a Z-source inverter system and control for general-purpose motor drives. The Z-source inverter system employs a unique LC network in the dc link and a small capacitor on the ac side of the diode front end. By controlling the shoot-through duty cycle, the Z-source can produce any desired output ac voltage, even greater than the line voltage. As a result, the new Z-source inverter system provides ride-through capability during voltage sags, reduces line harmonics, improves power factor and reliability, and extends output voltage range. Analysis, simulation, and experimental results will be presented to demonstrate these new features.     

Linearity of a Silicon Photodiode at 30 MHz and Its Effect on Heterodyne Measurements

The effect of optical irradiance on the linearity of a Si photodiode was studied. These results are compared for light modulated at 30 MHz and at dc as the optical irradiance was varied over a 9 decade range. We discuss how these results affect the use of this detector as a heterodyne receiver. As the optical irradiance varied from 10⁻² to 10⁺³ mW/cm², while maintaining constant total power, the photocurrent was constant to about 1%, but as the power density increased further, the photocurrent increased about 13%. At the highest densities that we could achieve, about 6×10⁷ mW/cm² there was only slight evidence of the onset of saturation. These results are of importance in our work to use optical heterodyne detection to measure filter transmittances over a wide dynamic range. The results provide guidelines for achieving maximum accuracy when using this particular diode as an optical heterodyne receiver.     

Evolution of Thermophysical Characteristics in Tin Oxide: From Pressed Powder Compact to Fired Porous Body

The thermal response of a ceramic body during firing will be controlled by its thermophysical characteristics. Laser flash measurements have been used to investigate the thermal conductivity of pressed powder compacts of pure tin oxide as a function of temperature. After an initial decrease up to 150°C attributed to removal of surface species, the thermal conductivity increases progressively with thermal treatment up to 1000°C. Because there is almost no variation in the pore volume fraction, the behavior is explained by grain boundary formation and neck growth, which increase the contact area between particles. Supporting evidence is given by an increase in mechanical strength. Finally, thermal treatment above 1000°C increases the thermal conductivity due to a reduction in the number of grain boundaries per unit length of heat path.     

Phonological competition and cooperation in form-related priming: Sequential and nonsequential processes in word production.

Phonological competition theory states that competition among discrepant segments of similar words leads to inhibition of high-frequency word-naming responses in form-related priming tasks. If segments are selected sequentially, competition should be greater for begin-related pairs (storage-story), in which discrepant segments are late in the words, than for end-related pairs (glory-story), in which discrepant segments are selected before the shared ones. This pattern was not observed in standard visual priming, probably because of the influence of parallel orthographic input. However, it was observed in a repetitive word-pair production task in which visual input was absent. The findings favor a class of models in which nonsequential activation of phonological content precedes sequential selection of the segments of words to be spoken. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implementing energy efficiency: Challenges and opportunities for rural electric co-operatives and small municipal utilities

Challenges in implementing demand side management (DSM) programs in rural electric co-operatives and small municipal utilities are not well understood, yet these organizations sell roughly 15% of electricity in the US, many are more coal-intensive than investor-owned utilities (IOUs), and they are politically important—rural electric co-operatives cover about 75% of the US land area and municipal utilities are found in every state except Hawaii. We provide a background on rural co-operatives and municipal utilities in the context of the US electric sector and highlight the challenges and opportunities of implementing DSM programs in these institutions. Where past studies of utility DSM have mostly focused on IOUs or consisted of qualitative case studies of municipal utilities with exemplary DSM performance, this study makes a unique contribution to the DSM literature by systematically analyzing an entire co-operative and municipal utility population in Minnesota through the use of a survey. In doing so, we provide policy recommendations relevant to energy planners and policy makers to support DSM in rural electric co-operatives and municipal utilities.     

High Count Rate Electron Probe Microanalysis

Reducing the measurement uncertainty of quantitative analyses made using electron probe microanalyzers (EPMA) requires a careful study of the individual uncertainties from each definable step of the measurement. Those steps include measuring the incident electron beam current and voltage, knowing the angle between the electron beam and the sample (takeoff angle), collecting the emitted x rays from the sample, comparing the emitted x-ray flux to known standards (to determine the k-ratio) and transformation of the k-ratio to concentration using algorithms which includes, as a minimum, the atomic number, absorption, and fluorescence corrections.This paper discusses the collection and counting of the emitted x rays, which are diffracted into the gas flow or sealed proportional x-ray detectors. The representation of the uncertainty in the number of collected x rays collected reduces as the number of counts increase. The uncertainty of the collected signal is fully described by Poisson statistics. Increasing the number of x rays collected involves either counting longer or at a higher counting rate. Counting longer means the analysis time increases and may become excessive to get to the desired uncertainty. Instrument drift also becomes an issue. Counting at higher rates has its limitations, which are a function of the detector physics and the detecting electronics.Since the beginning of EPMA analysis, analog electronics have been used to amplify and discriminate the x-ray induced ionizations within the proportional counter. This paper will discuss the use of digital electronics for this purpose. These electronics are similar to that used for energy dispersive analysis of x rays with either Si(Li) or Ge(Li) detectors except that the shaping time constants are much smaller.     

Neonatal benign sacrococcygeal teratoma with N-type rectobulbar fistula

A unique case of benign sacrococcygeal teratoma associated with an N-type rectobulbar fistula is reported.