8,500 research outputs found
Dry Matter and Minerals in Loblolly Pine Plantation on Four Arkansas Soils
Average contents of N, P, K, Ca, and Na and total above ground dry matter were determined in 19-year-old unthinned loblolly pine (Pinus taeda L.) plantations in southeastern Arkansas. Three stands were sampled on each of four sites: well and poorly drained coastal plain soils and well and poorly drained loessial soils. Total dry weights, determined from 15 felled trees on each of the 12 plots, ranged from 127,000 kg/ha on poorly drained loessial soil to 173,300 kg/ha on poorly drained coastal plain soil. Ranking of sites, in descending order of production of dry matter, P, K, and Na was: coastal plain poorly drained, coastal plain well drained, loess well drained, and loess poorly drained. Quantity of Ca in stemwood and stembark was 36% higher on well than poorly drained soils; P was 30% higher on coastal plain than loess soils. Results permit calculation of nutrient drain in timber harvests. Bark in 19-year-old plantations contained 44, 44, 25, and 50% of total N, P, K, and Ca in the stems
Numerical optimization techniques for bound circulation distribution for minimum induced drag of Nonplanar wings: Computer program documentation
A two dimensional advanced panel far-field potential flow model of the undistorted, interacting wakes of multiple lifting surfaces was developed which allows the determination of the spanwise bound circulation distribution required for minimum induced drag. This model was implemented in a FORTRAN computer program, the use of which is documented in this report. The nonplanar wakes are broken up into variable sized, flat panels, as chosen by the user. The wake vortex sheet strength is assumed to vary linearly over each of these panels, resulting in a quadratic variation of bound circulation. Panels are infinite in the streamwise direction. The theory is briefly summarized herein; sample results are given for multiple, nonplanar, lifting surfaces, and the use of the computer program is detailed in the appendixes
Design-thinking, making, and innovating: Fresh tools for the physician\u27s toolbox
Medical school education should foster creativity by enabling students to become \u27makers\u27 who prototype and design. Healthcare professionals and students experience pain points on a daily basis, but are not given the tools, training, or opportunity to help solve them in new, potentially better ways. The student physician of the future will learn these skills through collaborative workshops and having dedicated \u27innovation time.\u27 This pre-clinical curriculum would incorporate skills centered on (1) Digital Technology and Small Electronics (DTSE), (2) Textiles and Medical Materials (TMM), and (3) Rapid Prototyping Technologies (RPT). Complemented by an on-campus makerspace, students will be able to prototype and iterate on their ideas in a fun and accessible space. Designing and making among and between patients and healthcare professionals would change the current dynamic of medical education, empowering students to solve problems in healthcare even at an early stage in their career. By doing so, they will gain empathy, problem-solving abilities, and communication skills that will extend into clinical practice. Our proposed curriculum will equip medical students with the skills, passion, and curiosity to impact the future of healthcare
Inverter-Based Low-Voltage CCII- Design and Its Filter Application
This paper presents a negative type second-generation current conveyor (CCII-). It is based on an inverter-based low-voltage error amplifier, and a negative current mirror. The CCII- could be operated in a very low supply voltage such as ±0.5V. The proposed CCII- has wide input voltage range (±0.24V), wide output voltage (±0.24V) and wide output current range (±24mA). The proposed CCII- has no on-chip capacitors, so it can be designed with standard CMOS digital processes. Moreover, the architecture of the proposed circuit without cascoded MOSFET transistors is easily designed and suitable for low-voltage operation. The proposed CCII- has been fabricated in TSMC 0.18μm CMOS processes and it occupies 1189.91 x 1178.43μm2 (include PADs). It can also be validated by low voltage CCII filters
Nanoantenna-Microcavity Hybrids with Highly Cooperative Plasmonic-Photonic Coupling
Nanoantennas offer the ultimate spatial control over light by concentrating
optical energy well below the diffraction limit, whereas their quality factor
(Q) is constrained by large radiative and dissipative losses. Dielectric
microcavities, on the other hand, are capable of generating a high Q-factor
through an extended photon storage time but have a diffraction-limited optical
mode volume. Here we bridge the two worlds, by studying an exemplary hybrid
system integrating plasmonic gold nanorods acting as nanoantennas with an
on-resonance dielectric photonic crystal (PC) slab acting as a low-loss
microcavity and, more importantly, by synergistically combining their
advantages to produce a much stronger local field enhancement than that of the
separate entities. To achieve this synergy between the two polar opposite types
of nanophotonic resonant elements, we show that it is crucial to coordinate
both the dissipative loss of the nanoantenna and the Q-factor of the low-loss
cavity. In comparison to the antenna-cavity coupling approach using a
Fabry-Perot resonator, which has proved successful for resonant amplification
of the antenna's local field intensity, we theoretically and experimentally
show that coupling to a modest-Q PC guided resonance can produce a greater
amplification by at least an order of magnitude. The synergistic
nanoantenna-microcavity hybrid strategy opens new opportunities for further
enhancing nanoscale light-matter interactions to benefit numerous areas such as
nonlinear optics, nanolasers, plasmonic hot carrier technology, and
surface-enhanced Raman and infrared absorption spectroscopies.Comment: Revised version after acceptanc
An Algorithmic Framework for Multiobjective Optimization
Multiobjective (MO) optimization is an emerging field which is increasingly being encountered in many fields globally. Various metaheuristic techniques such as differential evolution (DE), genetic algorithm (GA), gravitational search algorithm (GSA), and particle swarm optimization (PSO) have been used in conjunction with scalarization techniques such as weighted sum approach and the normal-boundary intersection (NBI) method to solve MO problems. Nevertheless, many challenges still arise especially when dealing with problems with multiple objectives (especially in cases more than two). In addition, problems with extensive computational overhead emerge when dealing with hybrid algorithms. This paper discusses these issues by proposing an alternative framework that utilizes algorithmic concepts related to the problem structure for generating efficient and effective algorithms. This paper proposes a framework to generate new high-performance algorithms with minimal computational overhead for MO optimization
Interpretation of scanning tunneling quasiparticle interference and impurity states in cuprates
We apply a recently developed method combining first principles based Wannier
functions with solutions to the Bogoliubov-de Gennes equations to the problem
of interpreting STM data in cuprate superconductors. We show that the observed
images of Zn on the surface of BiSrCaCuO can only be understood
by accounting for the tails of the Cu Wannier functions, which include
significant weight on apical O sites in neighboring unit cells. This
calculation thus puts earlier crude "filter" theories on a microscopic
foundation and solves a long standing puzzle. We then study quasiparticle
interference phenomena induced by out-of-plane weak potential scatterers, and
show how patterns long observed in cuprates can be understood in terms of the
interference of Wannier functions above the surface. Our results show excellent
agreement with experiment and enable a better understanding of novel phenomena
in the cuprates via STM imaging.Comment: 5 pages, 5 figures, published version (Supplemental Material: 5
pages, 11 figures) for associated video file, see
http://itp.uni-frankfurt.de/~kreisel/QPI_BSCCO_BdG_p_W.mp
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