North Carolina State University

About: North Carolina State University is a education organization based out in Raleigh, North Carolina, United States. It is known for research contribution in the topics: Population & Thin film. The organization has 44161 authors who have published 101744 publications receiving 3456774 citations. The organization is also known as: NCSU & North Carolina State University at Raleigh.

Reversibly deformable and mechanically tunable fluidic antennas

Abstract: A method of manufacturing a fluidic structure is disclosed. A cavity that defines a shape of an element of the fluidic structure within a material is formed. The cavity is filled with liquid metal. The cavity is sealed. The fluidic structure behaves as an antenna. A fluidic antenna includes a material that defines a shape of the fluidic antenna by a cavity filled with liquid metal formed within the material, where the material further defines at least one mechanical property of the fluidic antenna.

An efficient chromatin immunoprecipitation (ChIP) protocol for studying histone modifications in Arabidopsis plants

Abstract: Chromatin immunoprecipitation (ChIP) is a powerful tool for the characterization of covalent histone modifications and DNA-histone interactions in vivo. The procedure includes DNA-histone cross-linking in chromatin, shearing DNA into smaller fragments, immunoprecipitation with antibodies against the histone modifications of interest, followed by PCR identification of associated DNA sequences. In this protocol, we describe a simplified and optimized version of ChIP assay by reducing the number of experimental steps and isolation solutions and shortening preparation times. We include a nuclear isolation step before chromatin shearing, which provides a good yield of high-quality DNA resulting in at least 15 mug of DNA from each immunoprecipitated sample (from 0.2 to 0.4 g of starting tissue material) sufficient to test > or =25 genes of interest. This simpler and cost-efficient protocol has been applied for histone-modification studies of various Arabidopsis thaliana tissues and is easy to adapt for other systems as well.

A comparison of unit root test criteria

Abstract: During the past 15 years, the ordinary least squares estimator and the corresponding pivotal statistic have been widely used for testing the unit-root hypothesis in autoregressive processes. Recently, several new criteria, based on maximum likelihood estimators and weighted symmetric estimators, have been proposed. In this article, we describe several different test criteria. Results from a Monte Carlo study that compares the power of the different criteria indicate that the new tests are more powerful against the stationary alternative. Of the procedures studied, the weighted symmetric estimator and the unconditional maximum likelihood estimator provide the most powerful tests against the stationary alternative. As an illustration, the weekly series of one-month treasury-bill rates is analyzed.

Supernova Remnants in the Sedov Expansion Phase: Thermal X-Ray Emission

Abstract: Improved calculations of X-ray spectra for supernova remnants (SNRs) in the Sedov-Taylor phase are reported, which for the first time include reliable atomic data for Fe L-shell lines. This new set of Sedov models also allows for a partial collisionless heating of electrons at the blast wave and for energy transfer from ions to electrons through Coulomb collisions. X-ray emission calculations are based on the updated Hamilton-Sarazin spectral model. The calculated X-ray spectra are successfully interpreted in terms of three distribution functions: the electron temperature and ionization timescale distributions, and the ionization timescale-averaged electron temperature distribution. The comparison of Sedov models with a frequently used single nonequilibrium ionization (NEI) timescale model reveals that this simple model is generally not an appropriate approximation to X-ray spectra of SNRs. We find instead that plane-parallel shocks provide a useful approximation to X-ray spectra of SNRs, particularly for young SNRs. Sedov X-ray models described here, together with simpler plane shock and single-ionization timescale models, have been implemented as standard models in the widely used XSPEC v11 spectral software package.

Control Strategies for Battery Energy Storage for Wind Farm Dispatching

Abstract: Integrating a battery energy storage system (BESS) with a large wind farm can smooth out the intermittent power from the wind farm. This paper focuses on development of a control strategy for optimal use of the BESS for this purpose. The paper considers a conventional feedback-based control scheme with revisions to incorporate the operating constraints of the BESS, such as state of charge limits, charge/discharge rate, and lifetime. The goal of the control is to have the BESS provide as much smoothing as possible so that the wind farm can be dispatched on an hourly basis based on the forecasted wind conditions. The effectiveness of this control strategy has been tested by using an actual wind farm data. Finally, it is shown that the control strategy is very important in determining the proper BESS size needed for this application.