Magnetism and superconductivity driven by identical 4ff states in a heavy-fermion metal

The apparently inimical relationship between magnetism and superconductivity has come under increasing scrutiny in a wide range of material classes, where the free energy landscape conspires to bring them in close proximity to each other. This is particularly the case when these phases microscopically interpenetrate, though the manner in which this can be accomplished remains to be fully comprehended. Here, we present combined measurements of elastic neutron scattering, magnetotransport, and heat capacity on a prototypical heavy fermion system, in which antiferromagnetism and superconductivity are observed. Monitoring the response of these states to the presence of the other, as well as to external thermal and magnetic perturbations, points to the possibility that they emerge from different parts of the Fermi surface. This enables a single 4$f$ state to be both localized and itinerant, thus accounting for the coexistence of magnetism and superconductivity.Comment: 4 pages, 4 figure

Low-Viscosity Nonaqueous Sulfolane-Amine-Methanol Solvent Blend for Reversible CO2 Capture

In this work, the absorption–desorption performance of CO2 in six new solvent blends of amine (diisopropylamine (DPA), 2-amino-2-methyl-1-propanol (AMP), methyldiethanolamine (MDEA), diethanolamine (DEA), diisopropanolamine (DIPA), and ethanolamine (MEA)), sulfolane, and methanol has been monitored using ATR-FTIR spectroscopy. Additionally, NMR-based species confirmation and solvent viscosity analysis were done for DPA solvent samples. The identified CO2 capture products are monomethyl carbonate (MMC), carbamate, carbonate, and bicarbonate anions in different ratios. The DPA solvent formed MMC entirely with 0.88 molCO2/molamine capture capacity, 0.48 molCO2/molamine cyclic capacity, and 3.28 mPa·s CO2-loaded solvent viscosity. MEA, DEA, DIPA, and MDEA were shown to produce a low or a negligible amount of MMC while AMP occupied an intermediate position.publishedVersio

Electron tunneling between two electrodes mediated by a molecular wire containing a redox center

We derive an explicit expression for the quantum conductivity of a molecular wire containing a redox center, which is embedded in an electrochemical environment. The redox center interacts with the solvent, and the average over the solvent configurations is performed numerically. Explicit calculations have been performed for a chain of three atoms. When the redox center interacts strongly with neighboring electronic levels, the current-potential curves show interesting features like rectification, current plateaus and negative differential resistance. Electronic spectroscopy of intermediate states can be performed at constant small bias by varying the electrochemical potential of the wire

Magnetic dipolar coupling and collective effects for binary information codification in cost-effective logic devices

Physical limitations foreshadow the eventual end to traditional Complementary Metal Oxide Semiconductor (CMOS) scaling. Therefore, interest has turned to various materials and technologies aimed to succeed to traditional CMOS. Magnetic Quantum dot Cellular Automata (MQCA) are one of these technologies. Working MQCA arrays require very complex techniques and an excellent control on the geometry of the nanomagnets and on the quality of the magnetic thin film, thus limiting the possibility for MQCA of representing a definite solution to cost-effective, high density and low power consumption device demand. Counter-intuitively, moving towards bigger sizes and lighter technologies it is still possible to develop multi-state logicdevices, as we demonstrated, whose main advantage is cost-effectiveness. Applications may be seen in low costlogicdevices where integration and computational power are not the main issue, eventually using flexible substrates and taking advantage of the intrinsic mechanical toughness of systems where long range interactions do not need wirings. We realized cobalt micrometric MQCA arrays by means of Electron Beam Lithography, exploiting cost-effective processes such as lift-off and RF sputtering that usually are avoided due to their low control on array geometry and film roughness. Information relative to the magnetic configuration of MQCA elements including their eventual magnetic interactions was obtained from Magnetic Force Microscope (MFM) images, enhanced by means of a numerical procedure and presented in differential maps. We report the existence of bi-stable magnetic patterns, as detected by MFM while sampling the z-component of magnetic induction field, arising from dipolar inter-element magnetostatic coupling, able to store and propagate binaryinformation. This is achieved despite the array quality and element magnetic state, which are low and multi-domain, respectively. We discuss in detail shape, inter-element spacing and dot profile effects on the magneticcoupling. Numerical Finite Element Method (FEM) simulations show a possible microspin arrangement producing such magnetostatic couplin

A monitoring campaign (2013-2020) of ESA's Mars Express to study interplanetary plasma scintillation

The radio signal transmitted by the Mars Express (MEX) spacecraft was observed regularly between the years 2013-2020 at X-band (8.42 GHz) using the European Very Long Baseline Interferometry (EVN) network and University of Tasmania's telescopes. We present a method to describe the solar wind parameters by quantifying the effects of plasma on our radio signal. In doing so, we identify all the uncompensated effects on the radio signal and see which coronal processes drive them. From a technical standpoint, quantifying the effect of the plasma on the radio signal helps phase referencing for precision spacecraft tracking. The phase fluctuation of the signal was determined for Mars' orbit for solar elongation angles from 0 - 180 deg. The calculated phase residuals allow determination of the phase power spectrum. The total electron content (TEC) of the solar plasma along the line of sight is calculated by removing effects from mechanical and ionospheric noises. The spectral index was determined as $-2.43 \pm 0.11$ which is in agreement with Kolomogorov's turbulence. The theoretical models are consistent with observations at lower solar elongations however at higher solar elongation ($>$160 deg) we see the observed values to be higher. This can be caused when the uplink and downlink signals are positively correlated as a result of passing through identical plasma sheets.Comment: The paper has 13 figures and one table. It has been accepted for publication in PASA and the article will receive its DOI in a week's tim

Life cycle assessment and resource management options for bio-ethanol production from cane molasses in Indonesia

The intent of this thesis is to analyse the sustainability of producing bio-ethanol from cane molasses in Indonesia and its potential to replace gasoline in the transportation sector. A field trip was conducted in East Java, Indonesia, and data was gathered for analysis. Life cycle assessment (LCA) was performed to analyse the net emissions and energy consumption in the process chain. The greenhouse gas (GHG) emissions of the life cycle are 17.45 gCO2e per MJ of ethanol produced. In comparison to gasoline, this results in a 78% reduction in GHG emissions in the complete process chain. Net Energy Value (NEV) and Net Renewable Energy Value (NREV) were 6.65 MJ/l and 24 MJ/l. Energy yield ratio (ER) was 9.43 MJ of ethanol per MJ of fossil energy consumed in the process. Economic allocation was chosen for allocating resources between sugar and molasses. Sensitivity analysis of various parameters was performed. The emissions and energy values are highly sensitive to sugarcane yield, ethanol yield and the price of molasses. Alternative management options were considered for optimizing the life cycle. Utilizing ethanol from all the mills in Indonesia has a potential to replace 2.3% of all motor gasoline imports. This translates in import savings of 2.3 trillion IDR per year. Use of anaerobic digestion or oxidation ponds for waste water treatment is unviable due to high costs and issues with gas leakage. Utilizing 15% of cane trash in the mill can enable grid independency. Environmental impacts due to land use change (Direct & Indirect) can be crucial in overall GHG calculations. Governmental regulation is necessary to remove current economic hurdles to aid a smoother transition towards bioethanol production and utilization.Harnessing agricultural feedstock and residues for bioethanol production - towards a sustainable biofuel strategy in Indonesi