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Ni/Li Disordering in Layered Transition Metal Oxide: Electrochemical Impact, Origin, and Control
Lithium-ion batteries (LIBs) not only power most of today’s hybrid electric vehicles (HEV) and electric vehicles (EV) but also are considered as a very promising system for grid-level storage. Large-scale applications for LIBs require substantial improvement in energy density, cost, and lifetime. Layered Li(NixMnyCoz)O2 (NMC, x+y+z=1) materials from solid-solution approaches to LiMO2 (M = Ni, Mn, Co, etc) are the most promising candidates for their high reversible capacity, better environmental compatibility, and lower cost compared with the traditional LiCoO2. In order to further boost Li storage capacity, a great deal of attention has been directed toward developing Ni-rich NMCs. However, structural disorder as a result of Ni/Li exchange in octahedral sites becomes a critical issue when Ni content increases to high values, as it leads to a detrimental effect on Li diffusivity, cycling stability, first-cycle efficiency, and overall electrode performance. Increasing efforts have been dedicated to improving the electrochemical performance of NMC materials via reduction of cationic mixing. Therefore, it is important to summarize this research field and provide in-depth insight into impact of Ni/Li disorder on electrochemical characteristics in layered NMC materials and its origin to accelerate the future development of NMC materials with high performance. In this Account, we start by analyzing the impact of Ni/Li disorder on electrochemical characteristics in layered NMC materials. The antisite Ni in the Li layer can limit the rate performance by impeding the Li-ion transport. It will also degrade the cycling stability by inducing the anisotropic stress in the bulk structure. Nevertheless, the antisite Ni-ions don’t always bring drawbacks to the electrochemical performance, some studies including our works found that it can improve the thermal stability and the cycling structure stability of Ni-rich NMC materials. We next discussed the driving forces and the kinetic advantages accounting for the Ni/Li exchange and summarized that the steric effect of cation size and the magnetic interactions between TM cations are the two main driving forces to promote the Ni/Li exchange during synthesis procedure and the electrochemical cycling, and the low energy barrier of Ni2+ migration from the 3a site in TM layer to 3b site in Li layer further provides the kinetic advantage. Based on above understandings, we reviewed the progress made to control the Ni/Li disorder and summarized three main ways: (i) suppressing the driving force from the steric effect by ion exchange; (ii) tuning the magnetic interaction by cationic substitution; (iii) kinetic controlling of Ni migration. Finally, our brief outlooks on the future development of controlling the Ni/Li disorder in NMC materials are provided. It is believed that this Account will provide significant understanding and inspirations toward developing high-performance NMC materials with controlled Ni/Li disorder.
Integrated Two-Stage Alkaline-Oxidative Pretreatment of Hybrid Poplar. Part 1: Impact of Alkaline Pre-Extraction Conditions on Process Performance and Lignin Properties
We previously demonstrated that a two-stage pretreatment comprising of an alkaline pre-extraction followed by a Cu-catalyzed alkaline–oxidative treatment is effective at pretreating hardwoods under relatively mild reaction conditions. In this work, we focus on characterizing how biomass source and reaction conditions used during the alkaline pre-extraction impact the subsequent processing stages as well as lignin yields and properties. Specifically, three hybrid poplars were subjected to the first stage alkaline pre-extraction under various conditions including differences in time (15–300 min), temperature (95–155 °C), and alkali loadings (50–200 mg NaOH/g biomass), and the impact on total mass solubilization, lignin recovery, and lignin purity was determined. Empirical correlations were developed between reaction conditions and mass solubilization and lignin recovery during the pre-extraction stage. For select conditions, lignin properties were assessed and include β-O-4 content determined by 13C NMR, molecular mass distributions as determined by gel permeation chromatography, and susceptibility to depolymerization to aromatic monomers using thioacidolysis and formic acid catalyzed depolymerization. We found alkaline pre-extraction performed at higher temperatures generated lignins exhibiting lower contamination by polysaccharides, lower aromatic monomer yields from depolymerization, lower molar masses, and lower β-O-4 contents relative to the lower temperature pre-extractions. Lastly, the pre-extracted biomass from select conditions was assessed for its response to the subsequent Cu-catalyzed alkaline–oxidative treatment and enzymatic hydrolysis. It was demonstrated that minor differences in delignification during pre-extraction have quantifiable impacts on the subsequent efficacy of the second stage of pretreatment and enzymatic hydrolysis with improved lignin removal during the first pre-extraction stage resulting in improved hydrolysis yields.
Mesoscale Convective Systems Represented in High Resolution E3SMv2 and Impact of New Cloud and Convection Parameterizations
Mesoscale convective systems (MCSs) play an important role in modulating the global hydrological cycle, general circulation, and radiative energy budget. In this study, we evaluate MCS simulations in the second version of U.S. Department of Energy (DOE) Energy Exascale Earth System Model (E3SMv2). E3SMv2 atmosphere model (EAMv2) is run at the uniform 0.25? horizontal resolution. We track MCSs consistently in the model and observations using the PyFLEXTRKR algorithm, which defines MCS based on both cloud-top brightness temperature (Tb) and surface precipitation. Results from using Tb only to define MCS, commonly used in previous studies, are also discussed. Furthermore, sensitivity experiments are performed to examine the impact of new cloud and convection parameterizations developed for EAMv3 on simulated MCSs. Our results show that EAMv2 simulated MCS precipitation is largely underestimated in the tropics and contiguous United States. This is mainly attributed to the underestimated precipitation intensity in EAMv2. In contrast, the simulated MCS frequency becomes more comparable to observations if MCSs are defined only based on cloud-top Tb. The Tb-based MCS tracking method, however, includes many cloud systems with very weak precipitation which conflicts with the MCS definition. This result illustrates the importance of accounting for precipitation in evaluating simulated MCSs. We also find that the new physics parameterizations help increase the relative contribution of convective precipitation to total precipitation in the tropics, but the simulated MCS properties are generally not improved. This suggests that simulating MCSs will remain a challenge for the next version of E3SM.
Machine learning model to project the impact of COVID-19 on U.S. motor gasoline demand
Owing to the global lockdowns that resulted from the COVID-19 pandemic, fuel demand plummeted and the price of oil futures went negative in April 2020. Robust fuel demand projections are crucial to economic and energy planning and policy discussions. Here we incorporate pandemic projections and people's resulting travel and trip activities and fuel usage in a machine-learning-based model to project the US medium-term gasoline demand and study the impact of government intervention. We found that under the reference infection scenario, the US gasoline demand grows slowly after a quick rebound in May, and is unlikely to fully recover prior to October 2020. Under the reference and pessimistic scenario, continual lockdown (no reopening) could worsen the motor gasoline demand temporarily, but it helps the demand recover to a normal level quicker. Under the optimistic infection scenario, gasoline demand will recover close to the non-pandemic level by October 2020. The COVID 19 pandemic and consequent lockdown has had a substantial impact on mobility and therefore fuel demand and it is not clear when demand will recover. Ou et al. use a machine learning model that integrates health recovery scenarios to project the near-term future of gasoline demand.
Revisiting the climate impacts of cool roofs around the globe using an Earth system model
Not Available
A Cost of Tractability? Estimating Climate Change Impacts Using a Single Crop Market Understates Impacts on Market Conditions and Variability
Scientists estimate that U.S. Corn Belt crop yields will increase or decrease, on average, and become more variable with climate change. Corn and soybean farming dominates this region, but studies typically do not assess the joint impact of new distributions of corn and soybean yields on markets. We use a structural economic model with projections of climate-driven yield changes to simulate these effects. Our findings suggest that a narrow focus on a single crop in this key growing region risks underestimating the impact on price distributions and average crop receipts, and can lead to incorrect signs on estimated impacts.
Signatures of the Martian regolith components entrained in some impact-melt glasses in shergottites
Abstract not provided
Geochemically-Driven Petrophysical Transformations in Caney Shale and Their Impact on Reservoir Productivity
Geochemically-Driven Petrophysical Transformations in Caney Shale and Their Impact on Reservoir Productivity
HTGR technology economic/ business analysis and trade studies impacts. Impacts of HTGR commericialization on the U.S. economy
The approach to this task was to initially review the 2012 Business Plan and supporting analyses for the above impacts. With that understanding as a base, the Business Plan impacts are updated in terms of the GDP and job creation as a result of additional studies and inputs such as the revised market assessment from Task 1.1. For the impacts on U.S. competitiveness, the NGNP Industry Alliance team members have been utilized to provide inputs on supplier infrastructure development and on vendor capability.
The ISO 50001 Impact Estimator Tool (IET 50001 V1.1.4) - User Guide and Introduction to the ISO 50001 Impacts Methodology
ISO 50001-Energy management systems – Requirements with guidance for use, is an internationally developed standard that provides organizations with a flexible framework for implementing an energy management system (EnMS) with the goal of continual energy performance improvement. The ISO 50001 standard was first published in 2011 and has since seen growth in the number of certificates issued around the world, primarily in the industrial (agriculture, manufacturing, and mining) and service (commercial) sectors. Policy makers in many regions and countries are looking to or are already using ISO 50001 as a basis for energy efficiency, carbon reduction, and other energy performance improvement schemes. The Impact Estimator Tool 50001 (IET 50001 Tool) is a computational model developed to assist researchers and policy makers determine the potential impact of ISO 50001 implementation in the industrial and service (commercial) sectors for a given region or country. The IET 50001 Tool is based upon a methodology initially developed by the Lawrence Berkeley National Laboratory that has been improved upon and vetted by a group of international researchers. By using a commonly accepted and transparent methodology, users of the IET 50001 Tool can easily and clearly communicate the potential impact of ISO 50001 for a region or country.
High impact pressure regulator withstands impacts of over 15,000 g
High impact pressure regulator used with a high impact gas scannograph withstands impacts of over 15,000 g. By the passage of fluid through the first and second chambers of the regulator, the pressure of the scannograph is regulated from a specific input valve to the desired output pressure valve.
Prediction of impact force and duration during low velocity impact on circular composite laminates
Two simple and improved models--energy-balance and spring-mass--were developed to calculate impact force and duration during low velocity impact of circular composite plates. Both models include the contact deformation of the plate and the impactor as well as bending, transverse shear, and membrane deformations of the plate. The plate was transversely isotropic graphite/epoxy composite laminate and the impactor was a steel sphere. Calculated impact forces from the two analyses agreed with each other. The analyses were verified by comparing the results with reported test data.
The record of impact on earth - Implications for a major Cretaceous/Tertiary impact event
Cratering mechanics suggests that if the proposed Cretaceous-Tertiary impact event occurred in the ocean, it may have been able to locally excavate the oceanic crust and bring upper mantle material to the surface, thereby creating a geophysical anomaly that has yet to be detected. If the siderophile enrichments in the Cretaceous-Tertiary boundary layer denote projectile-contaminated ejecta from a major impact, the source of this material will probably be ejecta which had been accelerated upwards as the projectile penetrated the target rocks. The difficulties in defining projectile types from the siderophile anomalies in the relatively well known environment of impact melt rocks suggest that more detailed geochemistry and mineralogy will be needed before the siderophile enrichments at the Cretaceous-Tertiary boundary can be linked to a specific meteoritic compositional class.
Prediction of impact force and duration due to low-velocity impact on circular composite laminates
Two simple and improved models - energy-balance and spring-mass - were developed to calculate impact force and duration during low velocity impact of circular composite plates. Both models include the contact deformation of the plate and the impactor as well as bending, transverse shear, and membrane deformations of the plate. The plate was transversely isotropic graphite/epoxy composite laminate and the impactor was a steel sphere. Calculated impact forces from the two analyses agreed with each other. The analyses were verified by comparing the results with reported test data.
Anomalous quartz from the Roter Kamm impact crater, Namibia - Evidence for post-impact hydrothermal activity?
Quartz pebbles from the Roter Kamm impact crater (the Namib Desert, SWA/Namibia) were examined for evidence of impact-induced hydrothermal activity, using results from microprobe analyses, neutron activation analyses, transmission IR spectroscopy, and X-ray diffractometry. It was found that the pebbles consisted of pure quartz, which contains three different types of fluid inclusions. These were identified as primary inclusions (5-10 microns) that record the formation conditions of the quartz, very small (less than 1 micron) secondary inclusions associated with the grain boundaries, and late inclusions of irregular size. It is concluded that the quartz and the primary inclusions may provide evidence for a postimpact phase of extensive hydrothermal activity, generated by the residual heat from the kinetic energy of the impact.
Long-term particle flux variability indicated by comparison of Interplanetary Dust Experiment (IDE) timed impacts for LDEF's first year in orbit with impact data for the entire 5.75-year orbital lifetime
The electronic sensors of the Interplanetary Dust Experiment (IDE) recorded precise impact times and approximate directions for submicron to approximately 100-micron size particles on all six primary sides of the spacecraft for the first 346 days of the Long Duration Exposure Facility (LDEF) orbital mission. Previously-reported analyses of the timed impact data have established their spatio-temporal features, including the demonstration that a preponderance of the particles in this regime are orbital debris and that a large fraction of the debris particles are encountered as megameter-size clouds, some of which persist for long times. Short-term fluxes within such clouds can rise several orders of magnitude above the long-term average. These finding are consistent with the results of the first catastrophic hypervelocity laboratory impacts on a real satellite, recently reported in the press. Analysis continues on the geometric and evolutionary characteristics of these clouds, as well as on the isolation and characterization of the natural micrometeoroid component in the IDE data, but the unexpectedly large short-term variations in debris flux raises the question of how representative an indication of the multi-year average flux is given by the nearly one year of timed data. It has, therefore, always been one of the goals of IDE to conduct an optical survey of the craters on the IDE detectors, to obtain full-mission fluxes for comparisons with the timed data. This work is underway, and the results presently in hand are significant. Optical scanning of the ram and wake (East and West) panels is complete, and it is clear that the first year was in some respects not representative of the subsequent years. The 5.75-year average flux on East panel was 90 percent of the value predicted by the average flux recorded during the first year, while it was only 34 percent on West panel. This suggests that western hemisphere spacecraft launches are a major contributor to the long-term flux and that their contribution is primarily in the smaller end of the size distribution. This conclusion follows from the fact that a closely-spaced series of launch failures (Titan, Delta, Ariane, and Challenger) caused a virtual hiatus in launch activity during a large part of the later years of the LDEF mission. We hope to provide a quantification of the particle size distribution function in this case.
The Manson impact structure - Its contribution to impact materials observed at the Cretaceous/Tertiary boundary
The Manson impact structure (MIS) in Iowa is an excellently preserved complex crater that formed 65.7 Ma ago at the K/T boundary. Drill and seismic data have been used to identify three primary terranes within the 35-km diameter crater: (1) an outermost ring graben composed of listric normal fault blocks that structurally preserve Paleozoic and Cretaceous strata, impact ejecta, and possibly earliest Tertiary lake sediments; (2) a crater moat region of slumped and fallback materials overlain by Tertiary lake sediments in most areas; and (3) a central peak of uplifted basement rock capped in many areas by impact breccia. It is argued that concentrations of Ir at a K/T boundary exposure near Gubbio, Italy and clasts of glass reported from the K/T boundary in Haiti are consistent with possible production in the MIS.