Equity, Mobility, and Sustainability: Analyzing Geographic and Demographic Disparities in Urban Bikeability

Cities currently produce 70% of the world’s greenhouse gas emissions, and the transportation sector accounts for a third of emissions from major cities. Consequently, improving urban infrastructure to support low-carbon methods of transportation such as cycling can play a critical role in emissions reductions. Improving bikeability also provides an affordable means of mobility and can present health and wellbeing benefits. Efforts to improve city bike infrastructure, however, have historically targeted privileged communities while overlooking underserved populations, such as low-income residents, people of color, and people with disabilities. To ensure urban bike networks serve all residents, it is important to evaluate where disparities in bikeability occur and who they impact. Building upon a multi-objective, network-based approach of quantifying bikeability, we analyze the geographic and demographic equity of cycling in three U.S. case study cities. We find that the network-wide bikeability of a city is not necessarily indicative of its equity level, as significant disparities in bikeability can exist even in a city that is highly bike-friendly overall. These disparities are observed when stratifying by socioeconomic status and when accounting for the accessibility needs of vulnerable cyclist populations, such as youth, seniors, women, and people with disabilities. Using this framework, future equity analyses can help inform urban planning decisions to provide sustainable transportation options that are more equitable and accessible for all

The organizational determinants of open innovation: a literature framework and future research directions

This paper aims to explore the organizational determinants of open innovation (OI). A review of 154 publications taken from management and innovation journals makes us identify four dimensions of ‘resource-related’ organizational factors that can determine OI: resource investment (what or how many resources are being invested), organizational structure (where resources are being attributed), human capital (who or what individual-level characteristics are) and the attitudes of individuals (how resources are being treated). We also identify core theoretical lenses and propose moderating and mediating mechanisms that can explain the relationship between the dimensions and OI. Based on this, we generate a literature framework and propose that the effects of organizational factors on the implementation of OI can be achieved by influencing firms’ dynamic abilities, and that these effects vary across costs-related contingencies. We also suggest several directions for addressing relevant unexplored questions within the framework

Elucidation of the Local and Long-Range Structural Changes that Occur in Germanium Anodes in Lithium-Ion Batteries

Metallic germanium is a promising anode material in secondary lithium-ion batteries (LIBs) due to its high theoretical capacity (1623 mAh/g) and low operating voltage, coupled with the high lithium-ion diffusivity and electronic conductivity of lithiated Ge. Here, the lithiation mechanism of micron-sized Ge anodes has been investigated with X-ray diffraction (XRD), pair distribution function (PDF) analysis, and in-/ex-situ high-resolution Li-7 solid-state nuclear magnetic resonance (NMR), utilizing the structural information and spectroscopic fingerprints obtained by characterizing a series of relevant Li(x)Gey model compounds. In contrast to previous work, which postulated the formation of Li9Ge4 upon initial lithiation, we show that crystalline Ge first reacts to form a mixture of amorphous and crystalline Li7Ge3 (space group P32(1)2). Although Li7Ge3 was proposed to be stable in a recent theoretical study of the Li-Ge phase diagram (Morris, A. J.; Grey, C. P.; Pickard, C. J. Phys. Rev. B: Condens. Matter Mater. Phys. 2014, 90, 054111), it had not been identified in prior experimental studies. Further lithiation results in the transformation of Li7Ge3, via a series of disordered phases with related structural motifs, to form a phase that locally resembles Li7Ge2, a process that involves the gradual breakage of the Ge-Ge bonds in the Ge-Ge dimers (dumbbells) on lithiation. Crystalline Li15Ge4 then grows, with an overlithiated phase, Li15+delta Ge4, being formed at the end of discharge. This study provides comprehensive experimental evidence, by using techniques that probe short-, medium-, and long-range order, for the structural transformations that occur on electrochemical lithiation of Ge; the results are consistent with corresponding theoretical studies regarding stable lithiated LixGey phases

Origin of additional capacities in metal oxide lithium-ion battery electrodes

Metal fluorides/oxides (MFx/MxOy) are promising electrodes for lithium-ion batteries that operate through conversion reactions. These reactions are associated with much higher energy densities than intercalation reactions. The fluorides/oxides also exhibit additional reversible capacity beyond their theoretical capacity through mechanisms that are still poorly understood, in part owing to the difficulty in characterizing structure at the nanoscale, particularly at buried interfaces. This study employs high-resolution multinuclear/multidimensional solid-state NMR techniques, with in situ synchrotron-based techniques, to study the prototype conversion material RuO2. The experiments, together with theoretical calculations, show that a major contribution to the extra capacity in this system is due to the generation of LiOH and its subsequent reversible reaction with Li to form Li2O and LiH. The research demonstrates a protocol for studying the structure and spatial proximities of nanostructures formed in this system, including the amorphous solid electrolyte interphase that grows on battery electrodes

Structures of Delithiated and Degraded LiFeBO₃, and Their Distinct Changes upon Electrochemical Cycling

Lithium iron borate (LiFeBO₃) has a high theoretical specific capacity (220 mAh/g), which is competitive with leading cathode candidates for next-generation lithium-ion batteries. However, a major factor making it difficult to fully access this capacity is a competing oxidative process that leads to degradation of the LiFeBO₃ structure. The pristine, delithiated, and degraded phases of LiFeBO₃ share a common framework with a cell volume that varies by less than 2%, making it difficult to resolve the nature of the delithiation and degradation mechanisms by conventional X-ray powder diffraction studies. A comprehensive study of the structural evolution of LiFeBO₃ during (de)­lithiation and degradation was therefore carried out using a wide array of bulk and local structural characterization techniques, both in situ and ex situ, with complementary electrochemical studies. Delithiation of LiFeBO₃ starts with the production of Li_<i>t</i>FeBO₃ (<i>t</i> ≈ 0.5) through a two-phase reaction, and the subsequent delithiation of this phase to form Li_{<i>t</i>–<i>x</i>}FeBO₃ (<i>x</i> < 0.5). However, the large overpotential needed to drive the initial two-phase delithiation reaction results in the simultaneous observation of further delithiated solid-solution products of Li_{<i>t</i>–<i>x</i>}FeBO₃ under normal conditions of electrochemical cycling. The degradation of LiFeBO₃ also results in oxidation to produce a Li-deficient phase D-Li_<i>d</i>FeBO₃ (<i>d</i> ≈ 0.5, based on the observed Fe valence of ∼2.5+). However, it is shown through synchrotron X-ray diffraction, neutron diffraction, and high-resolution transmission electron microscopy studies that the degradation process results in an irreversible disordering of Fe onto the Li site, resulting in the formation of a distinct degraded phase, which cannot be electrochemically converted back to LiFeBO₃ at room temperature. The Li-containing degraded phase cannot be fully delithiated, but it can reversibly cycle Li (D-Li_{<i>d</i>+<i>y</i>}FeBO₃) at a thermodynamic potential of ∼1.8 V that is substantially reduced relative to the pristine phase (∼2.8 V)

Identifying the chemical and structural irreversibility in LiNi0.8Co0.15Al0.05O2 - a model compound for classical layered intercalation

Anisotropic disorder along the c-axis results from static disorder

Effects of a patient-derived de novo coding alteration of CACNA1I in mice connect a schizophrenia risk gene with sleep spindle deficits

© 2020, The Author(s). CACNA1I, a schizophrenia risk gene, encodes a subtype of voltage-gated T-type calcium channel CaV3.3. We previously reported that a patient-derived missense de novo mutation (R1346H) of CACNA1I impaired CaV3.3 channel function. Here, we generated CaV3.3-RH knock-in animals, along with mice lacking CaV3.3, to investigate the biological impact of R1346H (RH) variation. We found that RH mutation altered cellular excitability in the thalamic reticular nucleus (TRN), where CaV3.3 is abundantly expressed. Moreover, RH mutation produced marked deficits in sleep spindle occurrence and morphology throughout non-rapid eye movement (NREM) sleep, while CaV3.3 haploinsufficiency gave rise to largely normal spindles. Therefore, mice harboring the RH mutation provide a patient derived genetic model not only to dissect the spindle biology but also to evaluate the effects of pharmacological reagents in normalizing sleep spindle deficits. Importantly, our analyses highlighted the significance of characterizing individual spindles and strengthen the inferences we can make across species over sleep spindles. In conclusion, this study established a translational link between a genetic allele and spindle deficits during NREM observed in schizophrenia patients, representing a key step toward testing the hypothesis that normalizing spindles may be beneficial for schizophrenia patients

Origin of additional capacities in metal oxide lithium-ion battery electrodes

Metal fluorides/oxides (MFx/MxOy) are promising electrodes for lithium-ion batteries that operate through conversion reactions. These reactions are associated with much higher energy densities than intercalation reactions. The fluorides/oxides also exhibit additional reversible capacity beyond their theoretical capacity through mechanisms that are still poorly understood, in part owing to the difficulty in characterizing structure at the nanoscale, particularly at buried interfaces. This study employs high-resolution multinuclear/multidimensional solid-state NMR techniques, with in situ synchrotron-based techniques, to study the prototype conversion material RuO2. The experiments, together with theoretical calculations, show that a major contribution to the extra capacity in this system is due to the generation of LiOH and its subsequent reversible reaction with Li to form Li2O and LiH. The research demonstrates a protocol for studying the structure and spatial proximities of nanostructures formed in this system, including the amorphous solid electrolyte interphase that grows on battery electrodes