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.

Variation in Lignin Content and Composition (Mechanisms of Control and Implications for the Genetic Improvement of Plants).

Abstract: Lignin, a complex phenolic polymer, is important for mechanical support, water transport, and defense in vaseular plants. Compressive strength and hydrophobicity of xylem cell walls are imparted by the lignin polymer, which is deposited during the terminal differentiation of tracheids and other cell types. The resistance of xylem to compressive stresses imposed by water transport and by the mass of the plants is important to growth and development. In addition, the insolubility and complexity of the lignin polymer makes it resistant to degradation by most microorganisms. Therefore, lignin serves an important function in plant defense. Variation in lignin content, composition, and location is likely to affect these essential processes. The constraints on the amount, composition, and localization of lignin for normal xylem function and plant defense are not known. Lignin composition, quantity, and distribution also affect the agroindustrial uses of plant material. Digestibility and dietary conversion of herbaceous crops are affected by differences in lignin content and composition (Akin et al., 1986, 1991). Lignin is an undesirable component in the conversion of wood into pulp and paper; remova1 of lignin is a major step in the paper making process. Furthermore, the resistance of lignin to microbial degradation enhances its persistence in soils. Lignin is, therefore, a significant component in the global carbon cycle. The mechanisms of control of lignin composition and quantity have wide implications regarding the adaptation and evolution of land plants and provide a basis for improved genetic manipulation of lignin for agroindustrial end uses. In this Update, we will focus on the levels of control of lignin variation, including (a) metabolic control, (b) regulation of individual enzymes in the biosynthetic pathway, and (c) regulation of gene expression. These levels of regulation affect variation in lignin content, quality, and distribution. Finally, the implications of these regulatory mechanisms for the genetic improvement of lignin for

The increasing importance of atmospheric demand for ecosystem water and carbon fluxes

Abstract: US Department of Energy; National Science Foundation (NSF) [DEB 1552747]; NSF [DEB 1552976, EF 1241881, EAR 125501, EAR 155489]; NOAA/GFDL-Princeton University Cooperative Institute for Climate Science

Coordinating Hundreds of Cooperative, Autonomous Vehicles in Warehouses

Abstract: The Kiva warehouse-management system creates a new paradigm for pick-pack-and-ship warehouses that significantly improves worker productivity. The Kiva system uses movable storage shelves that can be lifted by small, autonomous robots. By bringing the product to the worker, productivity is increased by a factor of two or more, while simultaneously improving accountability and flexibility. A Kiva installation for a large distribution center may require 500 or more vehicles. As such, the Kiva system represents the first commercially available, large-scale autonomous robot system. The first permanent installation of a Kiva system was deployed in the summer of 2006.

Mechanical Properties and Stacking Fault Energies of NiFeCrCoMn High-Entropy Alloy

Abstract: Materials with low stacking fault energies have been long sought for their many desirable mechanical attributes. Although there have been many successful reports of low stacking fault alloys (for example Cu-based and Mg-based), many have lacked sufficient strength to be relevant for structural applications. The recent discovery and development of multicomponent equiatomic alloys (or high-entropy alloys) that form as simple solid solutions on ideal lattices has opened the door to investigate changes in stacking fault energy in materials that naturally exhibit high mechanical strength. We report in this article our efforts to determine the stacking fault energies of two- to five-component alloys. A range of methods that include ball milling, arc melting, and casting, is used to synthesize the alloys. The resulting structure of the alloys is determined from x-ray diffraction measurements. First-principles electronic structure calculations are employed to determine elastic constants, lattice parameters, and Poisson’s ratios for the same alloys. These values are then used in conjunction with x-ray diffraction measurements to quantify stacking fault energies as a function of the number of components in the equiatomic alloys. We show that the stacking fault energies decrease with the number of components. Nonequiatomic alloys are also explored as a means to further reduce stacking fault energy. We show that this strategy leads to a means to further reduce the stacking fault energy in this class of alloys.