Exploring ocean acidification in undergraduate chemistry workshops

BACKGROUND Ocean acidification (OA) has profound impacts on marine ecosystems, particularly the Great Barrier Reef. While many studies investigate students’ understanding of climate change, there is a paucity of research on OA (Aubrecht, 2018; Danielson & Tanner, 2015). Literature suggests effective climate change education is affect-driven and personally relevant (Rousell & Cutter-Mackenzie-Knowles, 2020; Monroe et al., 2019). AIMS This study aims to investigate how to develop students’ understanding of and concern about OA. DESCRIPTION OF INTERVENTION Three first-year undergraduate chemistry workshops were designed with different pedagogical approaches. The Community of Inquiry workshop engaged students in philosophical discussion about the scientific, ethical, and social complexities of OA. In the Socioscientific Issues workshop students debated how we should respond to OA. The control workshop aligned with current practices and involved students solving chemistry problems within the context of OA. DESIGN AND METHODS The interventions were implemented in Semester 1 2022. A quasi-experimental design was used, students self-selected their workshop. Mixed-methods evaluation involved collection of pre- and post-test data and audio recording students’ group discussions during workshops. These data are undergoing statistical and thematic analysis, informed by literature. CONCLUSIONS Insights from this project will inform development of an OA inquiry-based learning opportunity that builds students’ knowledge and fosters care for the environment. REFERENCES Aubrecht, K. B. (2018). Teaching relevant climate change topics in undergraduate chemistry courses: Motivations, student misconceptions, and resources. Current Opinion in Green and Sustainable Chemistry, 13, 44-49. Danielson, K. I., & Tanner, K. D. (2015). Investigating undergraduate science students’ conceptions and misconceptions of ocean acidification. CBE–Life Sciences 14(3), ar29. Monroe, M. C., Plate, R. R., Oxarart, A., Bowers, A. & Chaves, W. A. (2019). Identifying effective climate change education strategies: A systematic review of the research. Environmental Education Research, 25(6), 791-812. Rousell, D. & Cutter-Mackenzie-Knowles, A. (2020). A systematic review of climate change education: Giving children and young people a ‘voice’ and a ‘hand’ in redressing climate change. Children's Geographies, 18(2), 191-208

Tailoring Single and Multiphoton Probabilities of a Single Photon On-Demand Source

As typically implemented, single photon sources cannot be made to produce single photons with high probability, while simultaneously suppressing the probability of yielding two or more photons. Because of this, single photon sources cannot really produce single photons on demand. We describe a multiplexed system that allows the probabilities of producing one and more photons to be adjusted independently, enabling a much better approximation of a source of single photons on demand.Comment: 4 pages, LaTex, 2 figures, twocolumn and RevTex Style for PR

Structure, Transport and Magnetic properties in La2x_{2x}Sr2−2x_{2-2x}Co2x_{2x}Ru2−2x_{2-2x}O6_{6}

The perovskite solid solutions of the type La$_{2x}$Sr$_{2-2x}$Co$_{2x}$Ru$_{2-2x}$O$_{6}$ with 0.25 $\leq$ x $\leq$ 0.75 have been investigated for their structural, magnetic and transport properties. All the compounds crystallize in double perovskite structure. The magnetization measurements indicate a complex magnetic ground state with strong competition between ferromagnetic and antiferromagnetic interactions. Resistivity of the compounds is in confirmation with hopping conduction behaviour though differences are noted especially for $x$ = 0.4 and 0.6. Most importantly, low field (50Oe) magnetization measurements display negative magnetization during the zero field cooled cycle. X-ray photoelectron spectroscopy measurements indicate presence of Co$^{2+}$/Co$^{3+}$ and Ru$^{4+}$/Ru$^{5+}$ redox couples in all compositions except $x$ = 0.5. Presence of magnetic ions like Ru$^{4+}$ and Co$^{3+}$ gives rise to additional ferromagnetic (Ru-rich) and antiferromagnetic sublattices and also explains the observed negative magnetization.Comment: Accepted for publication in J. Magn. Magn. Mate

Integrated CO2 capture-fixation chemistry via interfacial ionic liquid catalyst in laminar gas/liquid flow

Simultaneous capture of carbon dioxide (CO2) and its utilization with subsequent work-up would significantly enhance the competitiveness of CO2-based sustainable chemistry over petroleum-based chemistry. Here we report an interfacial catalytic reaction platform for an integrated autonomous process of simultaneously capturing/fixing CO2 in gas-liquid laminar flow with subsequently providing a work-up step. The continuous-flow microreactor has built-in silicon nanowires (SiNWs) with immobilized ionic liquid catalysts on tips of cone-shaped nanowire bundles. Because of the superamphiphobic SiNWs, a stable gas-liquid interface maintains between liquid flow of organoamines in upper part and gas flow of CO2 in bottom part of channel. The intimate and direct contact of the binary reagents leads to enhanced mass transfer and facilitating reactions. The autonomous integrated platform produces and isolates 2-oxazolidinones and quinazolines-2,4(1H,3H)-diones with 81-97% yields under mild conditions. The platform would enable direct CO2 utilization to produce high-valued specialty chemicals from flue gases without pre-separation and work-up steps. ? 2017 The Author(s).1115Ysciescopu

Paraxial propagation of a quantum charge in a random magnetic field

The paraxial (parabolic) theory of a near forward scattering of a quantum charged particle by a static magnetic field is presented. From the paraxial solution to the Aharonov-Bohm scattering problem the transverse transfered momentum (the Lorentz force) is found. Multiple magnetic scattering is considered for two models: (i) Gaussian $\delta$ -correlated random magnetic field; (ii) a random array of the Aharonov-Bohm magnetic flux line. The paraxial gauge-invariant two-particle Green function averaged with respect to the random field is found by an exact evaluation of the Feynman integral. It is shown that in spite of the anomalous character of the forward scattering, the transport properties can be described by the Boltzmann equation. The Landau quantization in the field of the Aharonov-Bohm lines is discussed.Comment: Figures and references added. Many typos corrected. RevTex, 25 pages, 9 figure

Reversible magnetization of MgB2 single crystals with a two-gap nature

We present reversible magnetization measurements on MgB2 single crystals in magnetic fields up to 2.5 T applied parallel to the crystal's c-axis. This magnetization is analyzed in terms of the Hao-Clem model, and various superconducting parameters, such as the critical fields [Hc(0) and Hc2(0)], the characteristic lengths [xi(0) and lambda(0)], and the Ginzburg-Landau parameter, kappa, are derived. The temperature dependence of the magnetic penetration depth, lambda(T), obtained from the Hao-Clem analysis could not be explained by theories assuming a single gap. Our data are well described by using a two-gap model.Comment: 20 pages, 1 table, 4 figures, will be published in Phys. Rev.

Astrophysical S-factor of the 7^7Be(p,γ)8p,\gamma)^8B reaction from Coulomb dissociation of 8^8B

The Coulomb dissociation method to obtain the astrophysical S-factor, $S_{17}(0)$, for the $^7$Be($p,\gamma)^8$B reaction at solar energies is investigated by analysing the recently measured data on the breakup reaction $^{208}$Pb$(^8$B,$^7$Be$~p)^{208}$Pb at 46.5 MeV/A beam energy. Breakup cross sections corresponding to E1, $E2$ and $M1$ transitions are calculated with a theory of Coulomb excitation that includes the effects of the Coulomb recoil as well as relativistic retardation. The interplay of nuclear and Coulomb contributions to the breakup process is studied by performing a full quantum mechanical calculation within the framework of the distorted-wave Born Approximation. In the kinematical regime of the present experiment, both nuclear as well as Coulomb-nuclear interference processes affect the pure Coulomb breakup cross sections very marginally. The $E2$ cross sections are strongly dependent on the model used to describe the structure of $^8$B. The value of $S_{17}(0)$ is deduced with and without $E2$ and $M1$ contributions added to the $E1$ cross sections and the results are discussed.Comment: 10 pages, with 4 figures included with psfig; Physics Letters B, in pres

Phase diagrams of spin ladders with ferromagnetic legs

The low-temperature properties of the spin S=1/2 ladder with anisotropic ferromagnetic legs are studied using the continuum limit bosonization approach. The weak-coupling ground state phase diagram of the model is obtained for a wide range of coupling constants and several unconventional gapless ''spin-liquid'' phases are shown to exist for ferromagnetic coupling. The behavior of the ladder system in the vicinity of the ferromagnetic instability point is discussed in detail.Comment: 11 pages, 4 figure

Experimental Implementation of Projective Measurement in Bell Basis

A scheme for direct projection of a quantum state on Bell states is described. The method is based on constructing an average Hamiltonian with Bell eigenstates and then, projecting the state on these eigenstates. The projection is performed by adding the results of a direct and time-reversed evolution. Experimental demonstration is shown for pairs of dipolar-coupled nuclear spins.Comment: 10 pages, 3 figures, submitte

Holographic principle in the BDL brane cosmology

We study the holographic principle in the brane cosmology. Especially we describe how to accommodate the 5D anti de Sitter Schwarzschild (AdSS$_5$) black hole in the Binetruy-Deffayet-Langlois (BDL) approach of brane cosmology. It is easy to make a connection between a mass $M$ of the AdSS$_5$ black hole and a conformal field theory (CFT)-radiation dominated universe on the brane in the moving domain wall approach. But this is not established in the BDL approach. In this case we use two parameters $C_1, C_2$ in the Friedmann equation. These arise from integration and are really related to the choice of initial bulk matter. If one chooses a bulk energy density $\rho_B$ to account for a mass $M$ of the AdSS$_5$ black hole and the static fifth dimension, a CFT-radiation term with $\rho_{CFT} \sim M/a^{4}$ comes out from the bulk matter without introducing a localized matter distribution on the brane. This means that the holographic principle can be established in the BDL brane cosmology.Comment: 9 pages, a version to appear in PR