US East Coast offshore wind energy resources and their relationship to peak‐time electricity demand

This study characterized the annual mean US East Coast (USEC) offshore wind energy (OWE) resource on the basis of 5 years of high‐resolution mesoscale model (Weather Research and Forecasting–Advanced Research Weather Research and Forecasting) results at 90 m height. Model output was evaluated against 23 buoys and nine offshore towers. Peak‐time electrical demand was analyzed to determine if OWE resources were coincident with the increased grid load. The most suitable locations for large‐scale development of OWE were prescribed, on the basis of the wind resource, bathymetry, hurricane risk and peak‐time generation potential. The offshore region from Virginia to Maine was found to have the most exceptional overall resource with annual turbine capacity factors (CF) between 40% and 50%, shallow water and low hurricane risk. The best summer resource during peak time, in water of ≤ 50 m depth, is found between Long Island, New York and Cape Cod, Massachusetts, due in part to regional upwelling, which often strengthens the sea breeze. In the South US region, the waters off North Carolina have adequate wind resource and shallow bathymetry but high hurricane risk. Overall, the resource from Florida to Maine out to 200 m depth, with the use of turbine CF cutoffs of 45% and 40%, is 965–1372 TWh (110–157 GW average). About one‐third of US or all of Florida to Maine electric demand can technically be provided with the use of USEC OWE. With the exception of summer, all peak‐time demand for Virginia to Maine can be satisfied with OWE in the waters off those states. Copyright © 2012 John Wiley & Sons, Ltd.     

Supersonic Flow Structure in the Entrance Part of a Mixing Chamber of 2D Model Ejector

The paper deals with experimental and numerical results of investigation into supersonic and transonic flow past a two-dimensional model ejector. Results of optical measurements show a flow structure and flow parameter development in the entrance part of the mixing chamber of the ejector. Numerical results are obtained by means of both the straight solution of shock waves in supersonic flow field using classical relations of parameters of shock waves and the Fluent 6 program. Results of numerical solutions are compared with experimental pictures of flow fields. Flow structure development in the mixing chamber is analysed in detail.     

Alcohol-related infractions among college students: Associations with subsequent drinking as a function of sensitivity to punishment.

Problematic alcohol use on college campuses is a significant concern. Violations of campus alcohol policies can lead to disciplinary action from the university. These and other alcohol-related legal infractions may be a sign of significant alcohol-related problems. However, few studies have focused on determining predictors of alcohol-related infractions among college students. Likewise, the role of infractions in reducing future use is unclear. In the present study, we tested whether alcohol-related infractions were associated with decreased alcohol use, and whether the effect of the infraction varied as a function of initial drinking levels, sensitivity to punishment (SP), and sensitivity to reward (SR) in a 6-month prospective design. Alcohol use, grade point average, and SR were significantly associated with receiving an alcohol-related infraction. For heavier drinkers, receiving an infraction was associated with decreased drinking at follow-up, and this decrease was most pronounced among those with higher sensitivity to punishment. SP appeared to increase responsiveness to the infraction, resulting in greater attenuation of drinking at follow-up. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Impact ionization suppression by quantum confinement: Effects onthe DC and microwave performance of narrow-gap channel InAs/AlSb HFET's

InAs/AlSb heterostructure field-effect transistors (HFET's) are subject to impact ionization induced short-channel effects because of the narrow InAs channel energy gap. In principle, the effective energy gap to overcome for impact ionization can be increased by quantum confinement (channel quantization) to alleviate impact ionization related nonidealities such as the kink effect and a high gate leakage current. We have studied the effects of quantum well thickness on the dc and microwave performance of narrow-gap InAs/AlSb HFET's fabricated on nominally identical epitaxial layers which differ only by their quantum well thickness. We show that a thinner quantum well postpones the onset of impact ionization and suppresses short-channel effects. As expected, the output conductance g_DS and the gate leakage current are reduced. The f_MAX/f_T ratio is also significantly improved when the InAs well thickness is reduced from 100 to 50 Å. The use of the thinner well reduces the cutoff frequency f_T, the transconductance g_m, and the current drive because of the reduced low-field mobility due to interface roughness scattering in thin InAs/AlSb channel layers: the low-field mobility was μ=21 000 and 9000 cm²/Vs for the 100- and 50-Å quantum wells, respectively. To our knowledge, the present work is the first study of the link between channel quantization, in-plane impact ionization, and device performance in narrow-gap channel HFET's     

Reaction analysis in stripline circuits

In this paper, a full-wave layered-interconnect simulator (UA-FWLIS), which is capable of simulating EM effects in packaging-interconnect problems, is introduced. Standard integral-equation-based method of moment (MoM) techniques are employed in UA-FWLIS. However, instead of using standard time-consuming numerical integration techniques, we have analytically evaluated the MoM reaction elements, thereby greatly improving the computational efficiency of the simulator. This paper illustrates the application of the simulator by employing it in the studies of coupling in a stripline structure and S-parameters for an interconnect     

Extension of an absolute vector error correction technique to wideband, high-frequency measurements

The authors have previously demonstrated how a transmitter (Tx), a reciprocal transmitter/receiver (Tx/Rx) signal path and two unidirectional receiver (Rx) paths can be used together with short, open and load standards for the absolute vector error correction (AVEC) of a Tx/Rx module. Once calibrated, this Tx/Rx module can then provide accurate vector measurements of the signals that are flowing into and/or out of the test port. In order to simplify the analysis, the AVEC technique was applied to a simplified baseband circuit that did not include frequency conversion mixers in a previous paper. Now, in this paper the authors first show how the AVEC technique can be extended to the vector calibration of high-frequency receivers that involve frequency conversion mixers. The authors then show how to calibrate a system that allows for wideband absolute phase relationship measurements of periodic modulated signals, provided that the same local oscillator is employed for the two down-conversion receivers, and different radio frequencies and intermediate frequencies are employed in these receivers. This novel AVEC technique is one of the key concepts in the design of a wideband absolute vector signal measurement system, which overcomes the limitations of traditional measurement instruments by combining the features of vector signal analysers, spectrum analysers and vector network analysers.     

Development of a new method for making high dynamic range, vector mixer characterisations

Vector network analysers (VNAs) employ static error models that allow for the removal of static instrumentation errors, thereby enabling the accurate measurement of vector scattering parameters for devices under test (DUTs). Since standard VNA error models are inherently based on relative measurements (i.e. either the reflected or transmitted signal is measured relative to the incident signal at the same frequency), they typically do not provide information about the magnitude and phase of the signal that is input into the DUT, or the signal that is transmitted through the DUT into the second receiver. Such information is crucial for VNA measurements of frequency-offsetting DUTs like mixers. In previous papers, the authors demonstrated how the inclusion of an additional bidirectional signal path allows for the absolute vector error correction (AVEC) of a one-port transmitter/receiver module, thereby allowing for the accurate vector measurement of the signals that are flowing into and/or out of the test port. The authors show how the AVEC method can be used to calibrate multi-port systems, thereby allowing for vector measurements of mixer DUTs (MUTs).     

Thermomechanical stress fields in high-temperature fibrous composites. II: Laminated plates

The results of Part I of this work are extended to laminated plates. It is assumed that the plates are, at most, macroscopically orthotropic, and that they are subjected to a uniform change in temperature and to in-plane mechanical loads. Average stresses and microstress fields are evaluated in each layer of the plate. Failure envelopes based on critical magnitudes of interface and axial matrix stresses are constructed for one of the SiC/Ti---Al---Nb systems of Part I.     

Gate metallurgy effects in InAs/AlSb HFETs: Preliminary results and demonstration of surface fermi level shifts

The effect of gate metallurgy on depletion-mode InAs/AlSb heterostructure field-effect transistors (HFETs) is studied for the first time by carefully comparing the characteristics of Al- and Ti/Au-gate transistors. HFETs fabricated simultaneously from the same molecular beam epitaxial layers and processed identically, but differing only in the metal used for the gate electrode, feature very different gate and drain I-V characteristics. The metal dependence indicates that the Fermi level is not completely pinned at the surface of InAs/AlSb quantum wells. We also show that the gate metal modifies the charge control properties of InAs/AlSb HFETs: Al-gate HFETs exhibit an enhanced kink effect accompanied by a marked transconductance compression at zero gate bias, whereas the Ti/Au-gate devices exhibit nearly kink-free drain characteristics. The gate metal dependence is shown to be a consequence of the increased channel equilibrium electron concentration accompanying the Al-metallization.