Removal of Boron from aqueous solutions by adsorption using fly ash, zeolite and demineralized lignite

In the present study for the purpose of removal of boron from water by adsorption using adsorbents like fly ash, natural zeolite and demineralized lignite was investigated. Boron in water was removed with fly ash, zeolite and demineralized lignite with different capacities. 94% boron was removed using fly ash. Batch experiments were conducted to test removal capacity, to obtain adsorption isotherms, thermodynamic and kinetic parameters. Boron removal by all adsorbents was affected by pH of solution; maximum adsorption was achieved at pH 10. Adsorption of boron on fly ash was investigated by Langmuir, Freundlich, Dubinin-Radushkevich models. Standard entropy and enthalpy changes of adsorption of boron on fly ash were, =S0 = -0.69 kJ/mol K and =H0 = -215.34 kJ/mol, respectively. The negative value of S0 indicated decreased randomness at the solid/solution interface during the adsorption boron on the fly ash sample. Negative values of H0 showed the exothermic nature of the process. The negative values of G0 implied that the adsorption of boron on fly ash samples was spontaneous. Adsorption of boron on fly ash occurred with a pseudo-second order kinetic model, intraparticle diffusion of boron species had also some effect in adsorption kinetics

Single-stage experimental evaluation of boundary layer bleed techniques for high lift stator blades. Part 3 - Data and performance of unslotted 0.75 hub diffusion factor stator

Boundary layer bleed techniques for high lift compressor stator blade

Single-Stage Experimental Evaluation of Boundary Layer Blowing Techniques for High Lift Stator Blades. III - Data and Performance of Single-Slotted 0.65 Hub Diffusion Factor Stator

Test on overall and blade element performance of single slotted 0.65 hub diffusion factor stator with self energized blowing boundary layer contro

Single-stage experimental evaluation of boundary layer blowing techniques for high lift stator blades. 4 - Data and performance of double-slotted 0.75 hub diffusion factor stator

Boundary layer hub diffusion-factor stator blowing techniqu

Phylogenetic signal in amphibian sensitivity to copper sulfate relative to experimental temperature

The release of large quantities of chemicals into the environment represents a major source of environmental disturbance. In recent years, the focus of ecotoxicology has shifted from describing the effects of chemical contaminants on individual species to developing more integrated approaches for predicting and evaluating long term effects of chemicals across species and ecosystems. Traditional ecotoxicology is typically based on data of sensitivity of a few surrogate species to a contaminant and often considers little variability in chemical sensitivity within and among taxonomic groups. This approach assumes that evolutionary history and phylogenetic relatedness among species have little or no impact on species’ sensitivity to chemical compounds. Few studies have tested this assumption. Using phylogenetic comparative methods and published data for amphibians, we show that sensitivity to copper sulfate, a commonly used pesticide, exhibits a strong phylogenetic signal when controlling for experimental temperature. Our results indicate that evolutionary history needs to be accounted for to make accurate predictions of amphibian sensitivity to this contaminant under different temperature scenarios. Since physiological and metabolic traits showing high phylogenetic signal likely underlie variation in species sensitivity to chemical stressors, future studies should evaluate and predict species vulnerability to pollutants using evolutionarily informed approaches

Structural Control of Metamaterial Oscillator Strength and Electric Field Enhancement at Terahertz Frequencies

The design of artificial nonlinear materials requires control over the internal resonant charge densities and local electric field distributions. We present a MM design with a structurally controllable oscillator strength and local electric field enhancement at terahertz frequencies. The MM consists of a split ring resonator (SRR) array stacked above an array of nonresonant closed conducting rings. An in-plane, lateral shift of a half unit cell between the SRR and closed ring arrays results in a decrease of the MM oscillator strength by a factor of 4 and a 40% change in the amplitude of the resonant electric field enhancement in the SRR capacitive gap. We use terahertz time-domain spectroscopy and numerical simulations to confirm our results and we propose a qualitative inductive coupling model to explain the observed electromagnetic reponse.Comment: 11 pages, 5 figure

Electromechanically Tunable Metasurface Transmission Waveplate at Terahertz Frequencies

Dynamic polarization control of light is essential for numerous applications ranging from enhanced imaging to materials characterization and identification. We present a reconfigurable terahertz metasurface quarter-waveplate consisting of electromechanically actuated micro-cantilever arrays. Our anisotropic metasurface enables tunable polarization conversion cantilever actuation. Specifically, voltage-based actuation provides mode selective control of the resonance frequency, enabling real-time tuning of the polarization state of the transmitted light. The polarization tunable metasurface has been fabricated using surface micromachining and characterized using terahertz time domain spectroscopy. We observe a ~230 GHz cantilever actuated frequency shift of the resonance mode, sufficient to modulate the transmitted wave from pure circular polarization to linear polarization. Our CMOS-compatible tunable quarter-waveplate enriches the library of terahertz optical components, thereby facilitating practical applications of terahertz technologies