Resnick Sustainability Institute

The Chinese economy has been recovering slowly from the global financial crisis, but it cannot achieve the same rapid development of the pre-recession period. Instead, the country has entered a new phase of economic development—a 'new normal'. We use a structural decomposition analysis and environmental input–output analysis to estimate the determinants of China's carbon emission changes during 2005–2012. China's imports are linked to a global multi-regional input–output model based on the Global Trade and Analysis Project database to calculate the embodied CO2 emissions in imports. We find that the global financial crisis has affected the drivers of China's carbon emission growth. From 2007 to 2010, the CO2 emissions induced by China's exports dropped, whereas emissions induced by capital formation grew rapidly. In the 'new normal', the strongest factors that offset CO2 emissions have shifted from efficiency gains to structural upgrading. Efficiency was the strongest factor offsetting China's CO2 emissions before 2010 but drove a 1.4% increase in emissions in the period 2010–2012. By contrast, production structure and consumption patterns caused a 2.6% and 1.3% decrease, respectively, in China's carbon emissions from 2010 to 2012. In addition, China tends to shift gradually from an investment to a consumption-driven economy. The proportion of CO2 emissions induced by consumption had a declining trend before 2010 but grew from 28.6%–29.1% during 2010–2012.

Non-aromatic peptides fluoresce under pressure.

A solar-driven CO2 reduction (CO2R) cell was constructed, consisting of a tandem GaAs/InGaP/TiO2/Ni photoanode in 1.0 M KOH(aq) (pH = 13.7) to facilitate the oxygen-evolution reaction (OER), a Pd/C nanoparticle-coated Ti mesh cathode in 2.8 M KHCO3(aq) (pH = 8.0) to perform the CO2R reaction, and a bipolar membrane to allow for steady-state operation of the catholyte and anolyte at different bulk pH values. At the operational current density of 8.5 mA cm–2, in 2.8 M KHCO3(aq), the cathode exhibited <100 mV overpotential and >94% Faradaic efficiency for the reduction of 1 atm of CO2(g) to formate. The anode exhibited a 320 ± 7 mV overpotential for the OER in 1.0 M KOH(aq), and the bipolar membrane exhibited ∼480 mV voltage loss with minimal product crossovers and >90 and >95% selectivity for protons and hydroxide ions, respectively. The bipolar membrane facilitated coupling between two electrodes and electrolytes, one for the CO2R reaction and one for the OER, that typically operate at mutually different pH values and produced a lower total cell overvoltage than known single-electrolyte CO2R systems while exhibiting ∼10% solar-to-fuels energy-conversion efficiency.

at 350 mV overpotential). The oxidation state of titanium and the potential of zero charge were also a function of the number of ALD cycles, indicating a correlation between oxidation state, potential of zero charge, and activity of the tuned electrocatalysts.

Almost all clean hydrogen that is used in industry is made by cogenerating low-cost hydrogen and other commodities. We propose a framework to make the world's hydrogen from low-cost cogeneration processes.

Abstract. China is the world's largest energy consumer and CO2 emitter. Cities contribute 85 % of the total CO2 emissions in China and thus are considered the key areas for implementing policies designed for climate change adaption and CO2 emission mitigation. However, understanding the CO2 emission status of Chinese cities remains a challenge, mainly owing to the lack of systematic statistics and poor data quality. This study presents a method for constructing a CO2 emissions inventory for Chinese cities in terms of the definition provided by the IPCC territorial emission accounting approach. We apply this method to compile CO2 emissions inventories for 20 Chinese cities. Each inventory covers 47 socioeconomic sectors, 20 energy types and 9 primary industry products. We find that cities are large emissions sources because of their intensive industrial activities, such as electricity generation, production for cement and other construction materials. Additionally, coal and its related products are the primary energy source to power Chinese cities, providing an average of 70 % of the total CO2 emissions. Understanding the emissions sources in Chinese cities using a concrete and consistent methodology is the basis for implementing any climate policy and goal.

Identifying subjects with mild cognitive impairment (MCI) most likely to decline in cognition over time is a major focus in Alzheimer's disease (AD) research. Neuroimaging biomarkers that predict decline would have great potential for increasing the efficacy of early intervention. In this study, we used high-resolution MRI, combined with a cortical unfolding technique to increase visibility of the convoluted medial temporal lobe (MTL), to assess whether gray matter thickness in subjects with MCI correlated to decline in cognition over two years. We found that thickness in the entorhinal (ERC) and subicular (Sub) cortices of MCI subjects at initial assessment correlated to change in memory encoding over two years (ERC: r = 0.34; P = .003) and Sub (r = 0.26; P = .011) but not delayed recall performance. Our findings suggest that aspects of memory performance may be differentially affected in the early stages of AD. Given the MTL's involvement in early stages of neurodegeneration in AD, clarifying the relationship of these brain regions and the link to resultant cognitive decline is critical in understanding disease progression.

We calculate the effective dielectric tensor of a metal film penetrated by cylindrical holes filled with a nematic liquid crystal (NLC) whose director is parallel to the film and can be controlled by a static magnetic field whose direction can be rotated in an arbitrary direction in the plane of the film. We consider both randomly distributed holes (using a Maxwell-Garnett approximation) and a square lattice of holes (using a Fourier technique). Both the holes and the lattice constant of the square lattice are assumed small compared to the wavelength. The films are found to exhibit extraordinary light transmission at special frequencies, ωsp, related to the surface plasmon (SP) resonances of the composite film, which depends on the direction of the applied magnetic field.

Electric power grid complexity is growing rapidly as we attempt to support technical, business, and societal goals for which power grids were not originally designed. To ensure grid stability and have the ability to remain reliable under highly dynamic destabilizing conditions requires that grid control systems evolve in ways that address transformational changes and the resultant operational problems. Ultra-large scale power system control architecture - a macro architecture for grid control that handles multi-objective, multi-constraint problems in a framework that can support coordinated control across utility organizational boundaries and, potentially, prosumer premises. The keys to this approach are three-fold: rectify the macro-structure of grid control to eliminate the emerging chaos; introduce two-axis distributed control; apply multi-level hierarchical optimization tools to grid control design. This paper describes emerging issues in grid control and provides reasons why the present path of grid control evolution is problematic and presents an ultra-large scale architecture for grid control that can solve today's problems and those expected over the next 30 years.

Progress in understanding resonant subwavelength structures has fueled an explosion of interest in fundamental processes and nanophotonic devices. The carrier density and optical properties of photonic nanostructures are typically fixed at the time of fabrication, but field effect tuning of the potential and carrier density enables the photonic dispersion to be altered, yielding new approaches to energy conversion and tunable radiative emission. Electrochemical in metals yields tunable resonances and reveals the plasmoelectric effect, a newly-discovered photoelectrochemical potential. Finally, while plasmons are usually described in a classical electromagnetic theory context, under single photon excitation quantum coherent states emerge. We demonstrate entanglement or coherent superposition states of single plasmons using two plasmon-quantum interference in chip-based plasmon waveguide directional couplers.

Coordinate-transformation-inspired optical devices have been mostly examined\nin the continuous-wave regime: the performance of an invisibility cloak, which\nhas been demonstrated for monochromatic excitation, %would inevitably is likely\nto deteriorate for short pulses. Here we investigate pulse dynamics of flexural\nwaves propagating in transformed plates. We propose a practical realization of\na waveshifter and a rotator for flexural waves based on the coordinate\ntransformation method. Time-resolved measurements reveal how the waveshifter\ndeviates a short pulse from its initial trajectory, with no reflection at the\nbend and no spatial and temporal distortion of the pulse. Extending our\nstrategy to cylindrical coordinates, we design a wave rotator. We demonstrate\nexperimentally how a pulsed plane wave is twisted inside the rotator, while its\nwavefront is recovered behind the rotator and the pulse shape is preserved,\nwith no extra time delay. We propose the realization of the dynamical mirage\neffect, where an obstacle appears oriented in a deceptive direction.\n

Media featuring both optical gain and disorder, such as random lasers,\nrepresent formidable challenges as subjects of research due to the high\ncomplexity of the light propagation within them; however, dramatic advances in\nthis nascent field have been furnished by the paradigm of applying wavefront\nshaping techniques to the beam pumping the system. We present here a\ntheoretical and experimental study employing this approach in a gain medium\nwhere the disorder arises not from random scattering but rather from the\nmultimodality of a waveguide: an amplifying multimode fiber. The shaping of the\ncore-guided pump prior to its injection affects the complex, speckle-like\npatterns of excitation within the fiber volume. Thus we are offered the\nintriguing prospect of manipulating the spatially heterogeneous gain in a\nsystem where the disorder, albeit highly complex, may be fully understood in\nterms of the discrete eigenmodes of a well-known waveguide. We study our medium\nin two different configurations: as an optical amplifier, and as a fiber laser.\nIn the first configuration we show that dependence upon the pump configuration,\nof the amplifier transmission function, surprisingly survives several physical\nmechanisms which at first sight would appear to severely limit it. This insight\nis then carried on to the lasing cavity configuration, where we find striking\nparallels between the behavior of the system and that of random lasers; more\nimportantly, the pump shaping shows a strong ability to control the complex\nemission, in particular - to selectively favor individual spectral lines and\nstabilize single-mode operation.\n