2,004 research outputs found
Computer program for Bessel and Hankel functions
A set of FORTRAN subroutines for calculating Bessel and Hankel functions is presented. The routines calculate Bessel and Hankel functions of the first and second kinds, as well as their derivatives, for wide ranges of integer order and real or complex argument in single or double precision. Depending on the order and argument, one of three evaluation methods is used: the power series definition, an Airy function expansion, or an asymptotic expansion. Routines to calculate Airy functions and their derivatives are also included
Continuous Synthesis of Zn2Al-CO3 Layered Double Hydroxides for the Adsorption of Reactive Dyes from Water
A novel pilot scale approach to continuous synthesis of layered double hydroxides (LDHs) was used to produce Zn2Al-CO3. The Zn2Al-CO3 was calcined and used in the adsorption of Reactive Black 5 (RB5) and Reactive Orange 16 (RO16) from water. The specific surface area of the LDH was 50.1 m2 g-1, while the surface area of the calcined LDH (MMO) was 57.8 m2 g-1. X-ray diffraction indicated complete breakdown of the LDH at 500 °C for 4 hours, with amorphous Al2O3 or AlOOH alongside ZnO. Reaction variables in the adsorption system; temperature, adsorbent dose, pH, initial concentration and the effect of competing anions were investigated across four temperatures from 10 °C to 40 °C. Maximum adsorption capacity calculated from the Langmuir isotherm was 895 mg g-1 and 589 mg g-1 at 20 °C, for RB5 and RO16, respectively. Intercalation of dye molecules was the main mode of adsorption, as indicated by shifts in (003) reflection from 11.5° to 4.5° and 3.2° for RB5 and RO16 respectively. Adsorption was best modelled by the pseudo 2nd order kinetic model. The intra-particle diffusion model indicated multiple stages of adsorption; surface adsorption occurs initially, followed by, intra-particle diffusion of dye molecules into the interlayer region. Regeneration through calcination resulted in an adsorption equal to 99 ± 2%
Janus Configurations, Chern-Simons Couplings, And The Theta-Angle in N=4 Super Yang-Mills Theory
We generalize the half-BPS Janus configuration of four-dimensional N=4 super
Yang-Mills theory to allow the theta-angle, as well as the gauge coupling, to
vary with position. We show that the existence of this generalization is
closely related to the existence of novel three-dimensional Chern-Simons
theories with N=4 supersymmetry. Another closely related problem, which we also
elucidate, is the D3-NS5 system in the presence of a four-dimensional
theta-angle.Comment: 66 p
A Model for Conducting Research with Learning Disabled Adolescents and Young Adults
This research was published by the KU Center for Research on Learning, formerly known as the University of Kansas Institute for Research in Learning Disabilities.Issues from the field of learning disabilities and the field of education in general which impact the learning disabled individual are discussed as they relate to research with learning disabled adolescents and young adults . Based on this knowledge of the context in which the LD adolescent is required to function, a research model that allows a commitment to programmatic research leading to the validation of interventions as well as the generation and investigation of new research questions is presented. Critical questions within the three research areas of the Institute epidemiology, intervention, and generalization-- are discussed as they relate to this research model
Monitoring Sustainable Global Development Along Shared Socioeconomic Pathways
Sustainable global development is one of the most prevalent challenges facing
the world today, hinging on the equilibrium between socioeconomic growth and
environmental sustainability. We propose approaches to monitor and quantify
sustainable development along the Shared Socioeconomic Pathways (SSPs),
including mathematically derived scoring algorithms, and machine learning
methods. These integrate socioeconomic and environmental datasets, to produce
an interpretable metric for SSP alignment. An initial study demonstrates
promising results, laying the groundwork for the application of different
methods to the monitoring of sustainable global development.Comment: 5 pages, 1 figure. Presented at NeurIPS 2023 Workshop: Tackling
Climate Change with Machine Learnin
Mercury Orbiter: Report of the Science Working Team
The results are presented of the Mercury Orbiter Science Working Team which held three workshops in 1988 to 1989 under the auspices of the Space Physics and Planetary Exploration Divisions of NASA Headquarters. Spacecraft engineering and mission design studies at the Jet Propulsion Lab were conducted in parallel with this effort and are detailed elsewhere. The findings of the engineering study, summarized herein, indicate that spin stabilized spacecraft carrying comprehensive particles and fields experiments and key planetology instruments in high elliptical orbits can survive and function in Mercury orbit without costly sun shields and active cooling systems
Towards the Continuous Hydrothermal Synthesis of ZnO@Mg2Al-CO3 Core-Shell Composite Nanomaterials
Core-shell Zinc Oxide/Layered Double Hydroxide (ZnO@LDH) composite nanomaterials have been produced by a one-step continuous hydrothermal synthesis process, in an attempt to further enhance the application potential of layered double hydroxide (LDH) nanomaterials. The synthesis involves two hydrothermal reactors in series with the first producing a ZnO core and the second producing the Mg2Al-CO3 shell. Crystal domain length of single phase ZnO and composite ZnO was 25 nm and 42 nm, respectively. The ZnO@LDH composite had a specific surface area of 76 m2 g−1, which was larger than ZnO or Mg2Al-CO3 when produced separately (53 m2 g−1 and 58 m2 g−1, respectively). The increased specific surface area is attributed to the structural arrangement of the Mg2Al-CO3 in the composite. Platelets are envisaged to nucleate on the core and grow outwards, thus reducing the face–face stacking that occurs in conventional Mg2Al-CO3 synthesis. The Mg/Al ratio in the single phase LDH was close to the theoretical ratio of 2, but the Mg/Al ratio in the composite was 1.27 due to the formation of Zn2Al-CO3 LDH from residual Zn2+ ions. NaOH concentration was also found to influence Mg/Al ratio, with lower NaOH resulting in a lower Mg/Al ratio. NaOH concentration also affected morphology and specific surface area, with reduced NaOH content in the second reaction stage causing a dramatic increase in specific surface area (> 250 m2 g−1). The formation of a core-shell composite material was achieved through continuous synthesis; however, the final product was not entirely ZnO@Mg2Al-CO3. The product contained a mixture of ZnO, Mg2Al-CO3, Zn2Al-CO3, and the composite material. Whilst further optimisation is required in order to remove other crystalline impurities from the synthesis, this research acts as a stepping stone towards the formation of composite materials via a one-step continuous synthesis
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