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We present a method to simulate ultrafast pump-probe time-resolved circular dichroism (TRCD) spectra based on time-dependent density functional theory trajectory surface hopping. The method is applied to simulate the TRCD spectrum along the photoinduced ring-opening of provitamin D. Simulations reveal that the initial decay of the signal is due to excited state relaxation, forming the rotationally flexible previtamin D. We further show that oscillations in the experimental TRCD spectrum arise from isomerizations between previtamin D rotamers with different chirality, which are associated with the helical conformation of the triene unit. We give a detailed description of the formation dynamics of different rotamers, playing a key role in the natural regulation vitamin D photosynthesis. Going beyond the sole extraction of decay rates, simulations greatly increase the amount of information that can be retrieved from ultrafast TRCD, making it a sensitive tool to unravel details in the sub-picosecond dynamics of photoinduced chirality changes.

Many physical, epidemiological, or physiological dynamical processes on networks support front-like propagation, where an initial localized perturbation grows and systematically invades all nodes in the network. A key question is then to extract estimates for the dynamics. In particular, if a single node is seeded at a small concentration, when will other nodes reach the same initial concentration? Here, motivated by the study of toxic protein propagation in neurodegenerative diseases, we present and compare three different estimates for the arrival time in order of increasing analytical complexity: the linear arrival time, obtained by linearizing the underlying system; the Lambert time, obtained by considering the interaction of two nodes; and the nonlinear arrival time, obtained by asymptotic techniques. We use the classic Fisher-Kolmogorov-Petrovsky-Piskunov equation as a paradigm for the dynamics and show that each method provides different insight and time estimates. Further, we show that the nonlinear asymptotic method also gives an approximate solution valid in the entire domain and the correct ordering of arrival regions over large regions of parameters and initial conditions.

Per- and polyfluoroalkyl substances (PFAS) contamination in water sources near potential PFAS users is well known. Therefore, it is useful for PFAS stakeholders to visualize hot-spot areas and bring attention to the water systems that are near to those areas. Towards this end, we extracted information about PFAS sources, drinking water information, sewer water information, and Source Water Assessment Protection Program (SWAPP) information from publicly available sources to create five different maps in ArcGIS Online that highlight PFAS contamination in relation to potential PFAS users. Following the FAIR (Findable, Accessible, Interoperable and Reusable) principles, we created a Figshare repository that includes all data and associated metadata with these five ArcGIS maps. Moreover, the Figshare repository includes a metadata description of the maps in JSON format that adheres to a draft Minimum Information about Geospatial Information System (MIAGIS) standard we have developed. We hope this MIAGIS draft will assist in establishing a GIS standards group that will develop the draft into a full standard for the wider GIS community. We have also developed a miagis Python package that facilitates the generation of a MIAGIS-compliant JSON metadata file.

In recent years, United States federal funding agencies, including the National Institutes of Health (NIH) and the National Science Foundation (NSF), have implemented public access policies to make research supported by funding from these federal agencies freely available to the public. Enforcement is primarily through annual and final reports submitted to these funding agencies, where all peer-reviewed publications must be registered through the appropriate mechanism as required by the specific federal funding agency. Unreported and/or incorrectly reported papers can result in delayed acceptance of annual and final reports and even funding delays for current and new research grants. So, it’s important to make sure every peer-reviewed publication is reported properly and in a timely manner. For large collaborative research efforts, the tracking and proper registration of peer-reviewed publications along with generation of accurate annual and final reports can create a large administrative burden. With large collaborative teams, it is easy for these administrative tasks to be overlooked, forgotten, or lost in the shuffle. In order to help with this reporting burden, we have developed the Academic Tracker software package, implemented in the Python 3 programming language and supporting Linux, Windows, and Mac operating systems. Academic Tracker helps with publication tracking and reporting by comprehensively searching major peer-reviewed publication tracking web portals, including PubMed, Crossref, ORCID, and Google Scholar, given a list of authors. Academic Tracker provides highly customizable reporting templates so information about the resulting publications is easily transformed into appropriate formats for tracking and reporting purposes. The source code and extensive documentation is hosted on GitHub (https://moseleybioinformaticslab.github.io/academic_tracker/) and is also available on the Python Package Index (https://pypi.org/project/academic_tracker) for easy installation.

In recent years, United States federal funding agencies, including the National Institutes of Health (NIH) and the National Science Foundation (NSF), have implemented public access policies to make research supported by funding from these federal agencies freely available to the public. Enforcement is primarily through annual and final reports submitted to these funding agencies, where all peer-reviewed publications must be registered through the appropriate mechanism as required by the specific federal funding agency. Unreported and/or incorrectly reported papers can result in delayed acceptance of annual and final reports and even funding delays for current and new research grants. So, it’s important to make sure every peer-reviewed publication is reported properly and in a timely manner. For large collaborative research efforts, the tracking and proper registration of peer-reviewed publications along with generation of accurate annual and final reports can create a large administrative burden. With large collaborative teams, it is easy for these administrative tasks to be overlooked, forgotten, or lost in the shuffle. In order to help with this reporting burden, we have developed the Academic Tracker software package, implemented in the Python 3 programming language and supporting Linux, Windows, and Mac operating systems. Academic Tracker helps with publication tracking and reporting by comprehensively searching major peer-reviewed publication tracking web portals, including PubMed, Crossref, ORCID, and Google Scholar, given a list of authors. Academic Tracker provides highly customizable reporting templates so information about the resulting publications is easily transformed into appropriate formats for tracking and reporting purposes. The source code and extensive documentation is hosted on GitHub (https://moseleybioinformaticslab.github.io/academic_tracker/) and is also available on the Python Package Index (https://pypi.org/project/academic_tracker) for easy installation.

One of the main technological challenges oxide-based solid-state batteries face today is the densification of their components to reach good interfacial contact. The most common approach requires co-sintering of the different components (electroactive material, catholyte and conducting additive) at high temperatures which often results in the inter-diffusion of elements that deteriorate the overall cathode performance. In this work, the impact of different carbon grades in the thermal response of LATP-NMC622-Carbon electrodes is evaluated and shown to significantly influence the chemical compatibility between components. By means of a combination of bulk and surface characterization techniques including gas adsorption, X-ray diffraction, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and thermogravimetric analysis, it is shown that carbons with low surface area are more adequate as result in higher oxidation temperatures and hence are less reactive.

In his landmark article for this journal, Francis Mechner (2017) presents a novel analysis of the confluence of unique combinations of variables accounting for aesthetic experiences, a phenomenon he calls synergetics. He proposes that artists, musicians, and writers use novel devices to capitalize on those effects. In my response to Mechner's fascinating article, I question the generality of such synergetic experiences to a wide array of audience members. I also question whether the evolutionary basis for aesthetic creativity accounts for the ubiquity of aesthetic activity, as Mechner suggests. I do share `Mechner’s emphasis on the importance of culturally nesting aesthetic contributions. But I suggest understanding aesthetic activities across cultures and subcultures requires additional mechanisms serving important bridging functions. I explore dispositional analysis, drawing on both Wittgenstein’s aesthetic language games and derived stimulus relationships. The behavioral functions of aesthetic experiences are those playing roles in cultural contingencies: motivational events, antecedent stimulus events, and consequences of aesthetic activities. Two kinds of aesthetic responses are discussed: 1) aesthetic creative responses by artists, writers or musicians, and 2) responses of audience members to those creations. These resulting aesthetic stimuli may play critical roles in cultural metacontingencies.

Replacing state-of-the-art graphite with metallic Li anodes could dramatically increase the energy density of Li-ion technology. However, efforts to achieve uniform Li plating and stripping in conventional liquid electrolytes have had limited success. An alternative approach is to use a solid electrolyte to stabilize the Li interface during cycling. One of the most promising solid electrolytes is Li 7 La 3 Zr 2 O 12 , which has high ionic conductivity at room temperature, high shear modulus and chemical and electrochemical stability against Li. Despite these properties, Li filament propagation has been observed through LLZO at current densities below what is practical. By combining recent achievements in reducing interface resistance and optimizing microstructure, we demonstrate Li cycling at current densities competitive with Li-ion. Li|LLZO|Li cells are capable of cycling at up to 0.9 ± 0.7 mA cm −2 , 3.8 ± 0.9 mA cm −2 , and 6.0 ± 0.7 mA cm -2 at room temperature, 40 and 60 °C, respectively. Extended stability is shown in Li plating/stripping tests that passed 3 mAh cm −2 charge per cycle for a cumulative capacity of 702 mAh cm −2 using a 1 mA cm −2 current density. These results demonstrate that solid-state batteries using metallic Li anodes can approach charge/discharge rates and cycling stability comparable to SOA Li-ion.

Thin-film lithium solid electrolytes can serve as passivation layers, interfacial coatings, and enable 3D solid-state batteries. Here we present an Atomic Layer Deposition (ALD) process for synthesis of amorphous lithium borate-carbonate (LBCO) films. These films exhibit ionic conductivities up to 2.2 × 10−6 S cm−1, six times greater than previously reported for any ALD solid electrolyte. First principles calculations trace the high conductivity to contributions from enhanced rotational motion of the carbonate and borate anions achieved by precise control of Li and C content by ALD. The high conductivity, coupled with a wide band gap and electrochemical stability window, leads to a total area specific resistance (ASR) of 0.9999 from 0–6 volts vs. Li metal. The LBCO ALD solid electrolyte exhibits stability upon exposure to air, and in contact with both Li metal anodes and cathode materials. Thin-film full cells containing Li metal electrodes exhibit high coulombic efficiency for over 150 cycles with no capacity fading. These characteristics make glassy LBCO a promising new material for solid-state Li metal batteries.

The garnet-type solid-state electrolyte, based on the nominal formula Li7La3Zr2O12 (LLZO), is unique in that it is a fast Li-ion conductor, exhibits sufficient mechanical properties, and is also chemically and electrochemically stable against metallic Li. Despite these promising attributes, additional challenges must be overcome before solid-state batteries based on LLZO are viable. Demonstrating low Li–LLZO interfacial resistance (R Li–LLZO) is a critical milestone along the path to commercialization. While several studies have characterized R Li–LLZO, nearly all report values significantly higher than conventional LIBs employing liquid electrolytes. Thus, strategies to reduce R Li–LLZO to values comparable to, or lower than, LIBs are needed [1]. In this study, the impact of surface chemistry on the interfacial resistance between the LLZO solid-state electrolyte and a metallic Li electrode is revealed [1]. Control of surface chemistry allows the interfacial resistance to be reduced to 2 Ω cm2, lower than that of liquid electrolytes, without the need for interlayer coatings. A mechanistic understanding of the origins of ultra-low resistance is provided by quantitatively evaluating the linkages between interfacial chemistry, Li wettability, and electrochemical phenomena. A combination of Li contact angle measurements, X-ray photoelectron spectroscopy (XPS), first-principles calculations, and impedance spectroscopy demonstrates that the presence of common LLZO surface contaminants, Li2CO3 and LiOH, result in poor wettability by Li and high interfacial resistance. On the basis of this mechanism, a simple procedure for removing these surface layers is demonstrated, which results in a dramatic increase in Li wetting and the elimination of nearly all interfacial resistance. The low interfacial resistance is maintained over one-hundred cycles and suggests a straightforward pathway to achieving high energy and power density solid-state batteries. [1] A. Sharafi, E. Kazyak, A. L. Davis, S. Yu, T Thompson, D. J. Siegel, N. P. Dasgupta, J. Sakamoto, Chem. Mater. 29, 7961(2017)

An innovative behavior analysis program was created, developed and matured, then unexpectedly imploded at Arizona State University between 1955 and 1970. The program included many who later became leaders in behavior analysis, and trained distinguished doctoral students. The conditions giving rise to the program in the first instance, and what caused the abrupt dissolution of the program in 1970 is the subject of this historical investigation. Consideration is given to more general implications of this series of events with possible lessons learned.

Lithium solid electrolytes are a promising platform for achieving high energy density, long-lasting, and safe rechargeable batteries, which could have widespread societal impact. In particular, the ceramic oxide garnet Li7La3Zr2O12 (LLZO) has been shown to be a promising electrolyte due to its stability and high ionic conductivity. Two major challenges for commercialization are the manufacture of thin layers and the creation of stable, low-impedance interfaces with both anode and cathode materials. Atomic layer deposition (ALD) has recently been shown to be a powerful method for depositing both solid electrolytes and interfacial layers to improve the stability and performance at electrode–electrolyte interfaces in battery systems. Herein, we present a thermal ALD process for LLZO, demonstrating the ability to tune composition within the amorphous as-deposited film, which is studied using in situ quartz crystal microbalance measurements. Postannealing using a variety of substrates and gas environments was ...

A novel sol-gel chemistry approach was developed to enable the simple integration of a cast-in-place, ambiently-dried insulation into high temperature applications. The insulation was silica-based and synthesized using methyltrimethoxysilane (MTMS) as the precursor. MTMS created a unique silica microstructure that was mechanically robust, macroporous, and superhydrophobic. To allow for casting into and around small, orthogonal features, zirconia fibers were added to increase stiffness and minimize contraction that could otherwise cause cracking during drying. Nano-sized titania powder was incorporated as an opacifier to reduce radiative heat transport. To assess relevance to high temperature thermoelectric generator technology, a comprehensive set of materials characterization experiments were conducted. The silica gel was thermally stable, retained superhydrophobicity with a water contact angle >150°, and showed a high electrical resistance >1 GΩ, regardless of heating temperature (up to 600 °C in Ar for 4 h). In addition, The silica-based thermal insulation exhibited a Young's modulus ∼3.7 MPa and a low thermal conductivity

Prader–Willi syndrome (PWS) is a genomic imprinting disorder characterized by infantile hypotonia with a poor suck and failure to thrive, hypogenitalism/hypogonadism, behavior and cognitive problems, hormone deficiencies, hyperphagia, and obesity. The Stanford Binet and Wechsler (WAIS-R; WISC-III) intelligence (IQ) tests were administered on 103 individuals with PWS from two separate cohorts [University of California, Irvine (UCI) (N = 56) and Vanderbilt University (N = 47)] and clinical information obtained including growth hormone (GH) treatment, PWS molecular classes, weight and height. Significantly higher IQ scores (p < .02) were found representing the vocabulary section of the Stanford Binet test in the growth hormone (GH) treated group when compared with non-GH treatment in the pediatric-based UCI PWS cohort with a trend for stabilization of vocabulary IQ scores with age in the GH treated maternal disomy (UPD) 15 subject group. Significant differences (p = .05) were also found in the adult-based Vanderbilt PWS cohort with 15q11-q13 deletion subjects having lower Verbal IQ scores compared with UPD 15. No difference in body mass index was identified based on the PWS molecular class or genetic subtype. Medical care and response to treatment with growth hormone may influence intelligence impacted by PWS genetic subtypes and possibly age, but more studies are needed.

The demand for energy storage systems has exponentially grown over the last decade. Li-ion battery, containing liquid electrolyte, is the most advanced and implemented technology for transport and stationary markets.[1] However, safety limitations of these systems mainly due to flammable and volatile electrolyte represent the major threat to reach complete market maturity.[2] Replacing liquid by safe solid electrolyte is foreseen as a realistic strategy while maintaining high energy and power densities. Among solid-state electrolyte materials, oxide-based ceramic electrolytes show high ionic conductivity, intrinsic safety and wide electrochemical window. The development of all-inorganic solid batteries is still at its infancy and presents various challenges due to the mechanical properties and processing of these materials.[3] High processing temperatures is certainly needed leading to chemical reactions and elemental diffusion, detrimental to maintain the battery performances. Developing a fully inorganic solid-state battery, consisting of a composite cathode, solid electrolyte and lithium metal anode by co-sintering the first two components, remains a great challenge. The composite cathode comprises the active material, and an ionic and an electronic conductive filler, that should form stable interfaces under processing as well as during cycling. But densification of oxide-based ceramic electrolytes requires temperatures as high as 1000 °C and co-sintering at these temperatures can induce numerous chemical side- reactions at composite cathode[4] which is detrimental to maintain the battery performance. To control the sintering process, the threshold temperature at which the material is stable and maintains the electrochemical performance needs to be defined and the reaction byproducts need to be identified to prevent and control their impact. In this work we will present the impact of heat treatment on the stability of composite cathode mixture with LiNi0.6Co0.2Mn0.2O2 (NMC), Li1+xAlxTi2-xP3O12 (LATP) and Ketjen black (KB). The study optimizes the threshold conditions such as heating atmosphere and temperature in determining the chemical and electrochemical compatibility of the composite and explains the reaction mechanism at threshold limits. Surface based analysis of the active material demonstrates that the NMC surface reconstruction acts as barrier to electrochemistry after heat treatment at temperatures above threshold limits. Also, it underlines the fact that each element of the composite has inevitable contribution to the reaction mechanism and is determined by both heating atmosphere and temperature. Alternatives to enhance the threshold limits will be proposed. Reference: [1] M. Armand and J. M. Tarascon, “Building better batteries,” Nature, vol. 451, no. 7179. Nature Publishing Group, pp. 652–657, 07-Feb-2008, doi: 10.1038/451652a. [2] D. Lisbona and T. Snee, “A review of hazards associated with primary lithium and lithium-ion batteries,” Process Saf. Environ. Prot., vol. 89, no. 6, pp. 434–442, Nov. 2011, doi: 10.1016/j.psep.2011.06.022. [3] K. Kerman, A. Luntz, V. Viswanathan, Y.-M. Chiang, and Z. Chen, “Review—Practical Challenges Hindering the Development of Solid State Li Ion Batteries,” J. Electrochem. Soc., vol. 164, no. 7, pp. A1731–A1744, Jun. 2017, doi: 10.1149/2.1571707jes. [4] L. Miara et al., “About the Compatibility between High Voltage Spinel Cathode Materials and Solid Oxide Electrolytes as a Function of Temperature,” vol. 8, no. 40, pp. 26842–26850, Oct. 2016, doi: 10.1021/acsami.6b09059.

The elastic modulus, fracture toughness, ionic conductivity, Li and water stability of dense (~ 97%) fine-grain (~ 10 μm) Li 1.2 Zr 1.9 Sr 0.1 (PO 4 ) 3 (LZSP) consolidated by reactive hot-pressing was investigated. Low values of elastic modulus (25.2 and 40.9 GPa), fracture toughness (0.29 and 0.37 MPa-m 1/2 ), total conductivity (2.1 × 10 − 5 S/cm) at room temperature were exhibited as a result of the presence of microcracks formed during cooling from the hot-pressing temperature. The lattice conductivity of LZSP is 0.85 × 10 − 4 S/cm with an activation energy for bulk conductivity of 0.29 eV. The results of Li/LZSP/Li cell impedance as a function of time and surface examination suggest that LZSP is not stable against metallic lithium. The results of the water stability test suggest that LZSP is a possible membrane for use in aqueous Li-Air cells. The results of this study reveal for the case of lithium zirconium phosphates are as follows: 1] a small grain size is required to prevent microcracking to avoid a reduction in total conductivity and mechanical properties and 2] even though they do not contain a transition metal cation they are not stable against Li at room temperature.

The recent discovery of fast ion-conducting solid electrolytes could enable solid-state and other advanced battery chemistries with higher energy densities and enhanced safety. In addition to high ionic conductivity, a viable electrolyte should also exhibit an electrochemical window that is wide enough to suppress undesirable electronic transport (i.e., self-discharge and/or short circuiting) arising from charge injection or extraction from the electrodes. Here, direct current chronoamperometry, alternating current electrochemical impedance spectroscopy, and optical absorption band gap measurements are combined with first-principles calculations to systematically characterize the electrochemical window of the promising superionic conductor Li7La3Zr2O12 (LLZO). Negligible electronic current was measured within LLZO for a wide range of voltages relevant for high-voltage cathodes. This auspicious behavior is consistent with both the large band gap (∼6 eV) predicted for LLZO and the absolute positions of its ...

The use of LiCoPO4 as a Li-ion cathode material can enable high energy 5 V batteries. However, LiCoPO4 shows limited cycle life and much less than theoretical energy density. In order to address these shortcomings, Fe, Cr and Si substituted-LiCoPO4 (Cr,Si-LiCo0.9Fe0.1PO4) was investigated as an improved LiCoPO4 based cathode material. Fe substitution greatly improves the cycle life and increases the energy density. Cr substitution further increases the energy density, cycle life and rate capability. Si substitution reduces the reactivity of the cathode with electrolyte thereby increasing cycle life. In combination, the substituents lead to a LiCoPO4 based cathode material with no capacity fade over 250 cycles in Li/Cr,Si-LiCo0.9Fe0.1PO4 half cells, a discharge capacity of 140 mAh g−1 at C/3 at an average discharge voltage of 4.78 V giving an energy density of 670 Wh per kg of cathode. In graphite/Cr,Si-LiCo0.9Fe0.1PO4 full Li-ion cells, the cathode material shows an energy density of 550 Wh per kg of cathode material at 1C rate for the initial cycles and 510 Wh per kg of cathode material at the 250th cycle.

Differences in thermal contraction/expansion and volume changes during discharge/charge cycles lead to internal stresses that ultimately cause degradation of solid-state composite cathodes, hindering the realization of their practical applications. The mechanical equilibrium equation is solved using the smoothed boundary method for the residual stresses induced by cooling from the sintering temperature and by (de)lithiation in polycrystalline composite microstructures that are similar to realistic solid-state composite cathodes. The composite slabs' deformations under the fabrication and operation conditions are also predicted from the simulations. The effects of cathode thickness and selections of different cathode materials on the resulting residual stresses and deformations are examined. It is found that the (de)lithiation stresses during cycling are more than twice the residual thermal stresses after sintering. Furthermore, the maximum (de)lithiation and residual thermal stresses are sensitive to the cathode thickness only when the cathode-layer thickness is comparable to that of the electrolyte separator layer. We also investigate the impact of the lithium site fraction of the cathode particles prior to sintering on the cycling stresses and deformations, which may pave the path toward an approach to mitigating mechanically induced degradation.

Talk given at the (internal) Simula Research Seminar, in Son (Norway)

We present a method to predict wavelength-dependent product quantum yields (PQYs) for photochemical reactions and applied it to Z/E-isomerization and several ring-closing reactions of Z-2,5-dimethyl-1,3,5-hexatriene and truncated previtamin D. Using branching ratios from surface hopping molecular dynamics, individual trajectories are correlated with the absorption spectra of their initial structures. The wavelength-dependent PQYs are computed by dividing the average spectrum of the initial structures of the product-forming trajectories by the average spectrum of all initial structures. Accurate absorption spectra are calculated using the correlated ADC(2) method with an implicit solvent. Calculations reproduce the experimentally found trend of increasing six-ring formation and decreasing Z/E-isomerization on the red side of the spectrum. Over all seven reactions studied, the mean absolute error (MAE) between experimental and calculated PQYs (MAE) amounts to 8.1%, with the largest MAE of 18.6%. For four reactions, predicted values agree quantitatively with experiments within 5.6%.

This paper is concerned with the study of the equilibrium exchange of ammonium ions with two natural zeolite samples sourced in Australia from Castle Mountain Zeolites and Zeolite Australia. A range of sorption models including Langmuir Vageler, Competitive Langmuir, Freundlich, Temkin, Dubinin Astakhov and Brouers–Sotolongo were applied in order to gain an insight as to the exchange process. In contrast to most previous studies, non-linear regression was used in all instances to determine the best fit of the experimental data. Castle Mountain natural zeolite was found to exhibit higher ammonium capacity than Zeolite Australia material when in the freshly received state, and this behavior was related to the greater amount of sodium ions present relative to calcium ions on the zeolite exchange sites. The zeolite capacity for ammonium ions was also found to be dependent on the solution normality, with 35–60% increase inuptake noted when increasing the ammonium concentration from 250 to 1000 mg/L. The optimal fit ofthe equilibrium data was achieved by the Freundlich expression as confirmed by use of Akaikes Information Criteria. It was emphasized that the bottle-point method chosen influenced the isotherm profile in several ways, and could lead to misleading interpretation of experiments, especially if the constant zeolite mass approach was followed. Pre-treatment of natural zeolite with acid and subsequently sodium hydroxide promoted the uptake of ammonium species by at least 90%. This paper highlighted the factors which should be taken into account when investigating ammonium ion exchange with natural zeolites.

Oils derived from vegetable oils tend to not meet the standards for industrial lubricants because of unacceptable low temperature properties, pour point (PP) and/or cloud point (CP). However, a catalytic amount of perchloric acid with oleic and coconut (coco) fatty acids produced a coco-oleic estolide. The resulting coco-oleic estolide was separated into two components based on the extent of oligomerization: coco-oleic dimer estolide and coco-oleic trimer plus estolide. These two estolides were then esterified with a series of different branched alcohols; the coco-oleic dimer estolide esters had the lowest PP = −45 °C when with esterified 2-hexyldecanol and PP = −39 °C with 2-octyldodecanol. The best CP performer from the same series was the 2-octyldodecanol ester, CP = −37 °C. The coco-oleic trimer plus estolide esters had slightly higher PPs (−24 to −39 °C) with the same alcohols. The viscosities and viscosity indexes were as expected in terms of trends. The coco-oleic dimer estolide esters ranged 27.5–51.7 cSt @ 40 °C and 3.0–9.5 cSt @ 100 °C, whereas the coco-oleic trimer plus estolide esters ranged 120.8–227.7 cSt @ 40 °C and 17.9–29.4 cSt at 100 °C for the same series as the dimer esters. Outside the series tested, an iso-stearyl trimer plus ester had the highest reported viscosity of 417.3 cSt @ 40 °C and 38.9 cSt @ 100 °C. Because these new branched estolide esters have excellent viscosity and low temperature physical properties without the addition of other chemicals, they minimize the effect on the environment while replacing nonrenewable products.

The oxide garnet material Li7La3Zr2O12 shows remarkably high ionic conductivity when doped with supervalent ions that are charge compensated by Li vacancies and is currently one of the best candidates for development of a technologically relevant solid electrolyte. Determination of optimal dopant concentration, however, has remained a persistent problem due to the extreme difficulty of establishing the actual (as compared to nominal) stoichiometry of intentionally doped materials and by the fact that it is still not entirely clear what level of lattice expansion/contraction best promotes ionic diffusion. By combining careful synthesis, neutron diffraction, high-resolution X-ray diffraction (XRD), Raman measurements, and density functional theory calculations, we show that structure and stoichiometry are intimately related such that the former can in many cases be used as a gauge of the latter. We show that different Li-vacancy creating supervalent ions (Al3+ vs Ta5+) affect the structure very differently,...

The effect of hot-pressing temperature on the microstructure and Li-ion transport of Al-doped, cubic Li7La3Zr2O12 (LLZO) was investigated. At fixed pressure (62 MPa), the relative density was 86%, 97%, and 99% when hot-pressing at 900°C, 1000°C, and 1100°C, respectively. Electrochemical impedance spectroscopy showed that the percent grain-boundary resistance decreased with increasing hot-pressing temperature. Hot pressing at 1100°C resulted in a total conductivity of 0.37 mS/cm at room temperature where the grain boundaries contributed to 8% of the total resistance; one of the lowest grain-boundary resistances reported. We believe hot pressing is an appealing technique to minimize grain-boundary resistance and enable correlations between LLZO composition and bulk ionic conductivity.

To investigate the role of tachysterol in the photophysical/photochemical regulation of vitamin D photosynthesis, we studied its electronic absorption properties and excited state dynamics using time-dependent density functional theory (TDDFT), second-order approximate coupled cluster theory (CC2), and non-adiabatic surface hopping molecular dynamics in the gas phase. In excellent agreement with experiments, the simulated electronic spectrum shows a broad absorption band with a remarkably higher extinction coefficient than the other vitamin D photoisomers provitamin D, lumisterol, and previtamin D. The broad band arises from the spectral overlap of four different ground state rotamers. After photoexcitation, the first excited singlet state (S1) decays with a lifetime of 882 fs. The S1 dynamics is characterized by a strong twisting of the central double bond. In 96% of all trajectories this is followed by unreactive relaxation to the ground state near a conical intersection. The double-bond twisting in the chemically unreactive trajectories induces a strong interconversion between the different rotamers. In 2.3% of the trajectories we observed [1,5]-sigmatropic hydrogen shift forming the partly deconjugated toxisterol D1. 1.4% previtamin D formation is observed via hula-twist double bond isomerization. In both reaction channels, we find a strong dependence between photoreactivity and dihedral angle conformation: hydrogen shift only occurs in cEc and cEt rotamers and double bond isomerization occurs mainly in cEc rotamers. Hence, our study confirms the previously formed hypothesis that cEc rotamers are more prone to previtamin D formation than other isomers. In addition, we also observe the formation of a cyclobutene-toxisterol in the hot ground state in 3 trajectories (0.7%). Due to its large extinction coefficient and mostly unreactive behavior, tachysterol acts mainly as a Sun shield suppressing previtamin D formation. Tachysterol shows stronger toxisterol formation than previtamin D and can thus be seen as the major degradation route of vitamin D. Absorption of low energy ultraviolet light by the cEc rotamer can lead to previtamin D formation. In addition, the cyclobutene-toxisterol, which possibly reacts thermally to previtamin D, is also preferably formed at long wavelengths. These two mechanisms are consistent with the wavelength dependent photochemistry found in experiments. Our study reinforces a recent hypothesis that tachysterol constitutes a source of previtamin D when only low energy ultraviolet light is available, as it is the case in winter or in the morning and evening hours of the day.

Transitioning skutterudite (SKD) thermoelectric technology from space to terrestrial power generation requires oxidation suppression technology. One approach involves the development of protective coatings consisting of the following properties: (i) low thermal conductivity to prevent parasitic heat loss, (ii) low electrical conductivity to prevent short-circuiting, (iii) coefficient(s) of thermal expansion matching that of the thermoelectric material, and (iv) adequate thermal stability and mechanical strength for durability. In this work, n-type Ba0.05Yb0.025CoSb3 and p-type Ce0.9Co0.5Fe3.5Sb12 were coated with a silica-based enamel to prevent their oxidation. This work demonstrates the efficacy of enamel coatings for suppressing oxidation of n-type SKD, and for the first time, p-type SKD in static and thermal cyclic heating tests up to 600 °C in air. The coating process, physical characterization of the enamel, and materials characterization data are presented and discussed.

A series of 26 different antioxidants and commercial antioxidant packages designed for petroleum-based materials, containing both natural and synthetic-based materials, were evaluated with dimeric coconut-oleic estolide 2-ethylhexyl ester (2-EH), a bio-based material. The different antioxidants were categorized into different classes of phenolic, aminic, and blended/others materials. The oxidation onset temperatures (OT) using non-isothermal pressurized differential scanning calorimetry (PDSC) were measured and recorded under previously reported standard conditions. The aminic series gave the best resistance to oxidation as defined by the PDSC method with OT of 246.6 and 244.7 °C for the best two performers, which was a 38 °C improvement over the uninhibited or unformulated dimer estolide material. The phenolic series, containing most of the naturally occurring antioxidants, was the least successful formulation package for the dimer estolide. The blended/other materials, which were specifically designed for petroleum-based lubricants, did not have the best OT, since the estolides and other bio-based materials interact differently than their petroleum counterparts. A number of potential antioxidants have been identified as useful additives for the estolides esters. The OT of the estolide and formulated materials correlated well with other bio-based materials such as biodiesel.

LiCoPO 4 is a promising cathode material for use in high voltage Li-ion batteries. One of the problems with LiCoPO 4 is limited cycle life. One possible cause for the limited cycle life of LiCoPO 4 is mechanical degradation. As a consequence, the mechanical properties, elastic modulus, E , and fracture toughness, K IC , of hot-pressed dense (~98%) polycrystalline (15–20 μm) single phase LiCoPO 4 were investigated. E for the hot-pressed LiCoPO 4 specimen is ~137 GPa while the E value for the LiCoPO 4 specimen after annealing at 600 °C is ~106 GPa. The fracture toughness of the hot-pressed LiCoPO 4 sample is ~0.41 MPa m 1/2 , which increased to ~0.53 MPa m 1/2 after annealing. These low K IC values reveal that LiCoPO 4 is a brittle material. It is believed that the decrease in E and increase in K IC with annealing is associated with a reduction in residual stress.

The thermoelectric skutterudite Ba0.3Co4Sb12 is a promising candidate for waste heat recovery applications. Recently, it was demonstrated that the addition of silver nanoparticles (AgNP) to Ba0.3Co4Sb12 increases both the thermoelectric figure of merit and electrical conductivity. This study is the first to examine the effect of AgNP addition on the material’s mechanical properties. This study also found that the Young’s modulus, E, shear modulus, G, and bulk modulus, B, decreased linearly with increasing volume fraction porosity, P. Resonant ultrasound spectroscopy was employed to measure the elastic moduli, and Vickers indentation was used to determine the hardness, H, and fracture toughness, K C. Trends in the mechanical properties as a function of grain size, porosity, and the AgNP are discussed in terms of the pertinent literature. While K C was independent of AgNP addition, porosity, and grain size, both E and H decreased linearly with increasing porosity. In addition, this study is the first to identify (i) the Ag3Sb phase formed and (ii) the enhanced densification that occurs when the AgNP is sintered with Ba0.3Co4Sb12 powders, where both effects are consistent with the eutectic and peritectic reactions observed in the binary phase diagram Ag–Sb. These eutectic/peritectic reactions may also be linked to the enhancement of electrical conductivity previously observed when Ag is added to Ba0.3Co4Sb12. Also, similar beneficial eutectic/peritectic reactions may be available for other systems where conductive particles are added to other antimonides or other thermoelectric systems.

LiCoPO 4 is a promising cathode material to enable high energy, abuse tolerant Li-ion batteries. However, LiCoPO 4 has relatively poor electronic conductivity which may be improved by chemical substitution. In this work, the ionic and electronic conductivities of dense, polycrystalline LiCoPO 4 and Fe 2+ /Fe 3+ -substituted LiCoPO 4 (Li 1− x Co 0.9 Fe 0.1 PO 4 ) are measured and compared. Both materials are predominantly ionic conductors with relatively good bulk ionic and relatively poor electronic conductivities. Li 1− x Co 0.9 Fe 0.1 PO 4 exhibits both higher bulk ionic and electronic conductivity. The increased bulk ionic conductivity of Li 1− x Co 0.9 Fe 0.1 PO 4 is believed to originate mainly from extra Li vacancies and the increased electronic conductivity is believed to originate mainly from creating more mobile hole polarons compared to LiCoPO 4 as a result of Fe 2+ /Fe 3+ substitution.

High concentration Electrolytes (HCEs) exhibit a small molar ratio of solvent to salt, usually in the range of 2…4:1. Localized Superconcentrated Electrolytes (LSEs) are derived from HCEs but contain a co-solvent that is used to dissipate the solvent-salt complexes, leading to significantly reduced viscosity and therefore improved conductivity. One of these co-solvents is 1,1,2,2-Tetrafluoroethyl 2,2,3,3-Tetrafluoropropyl Ether (TTE). They can be prepared using solvents that have a high anodic stability such as Sulfolane (SL) making them ideal candidates for cycling lithium metal in conjunction with advanced cathode materials above 4,5 V. Since the introduction of the LSE concept, proposed by Jiangfeng et al. [1] most published variations used Lithium bis(fluorosulfone)imid (LiFSI) as the conducting lithium salt [2]. The structurally similar salt Lithium bis-(trifluoromethanesulforyl)imid (LiTFSI) is commonly used in classical electrolytes, especially for Lithium-Sulfur batteries because of its good ion separation and resulting high conductivity. It has however rarely been used in LSEs to date [3]. Although LiFSI and LiTFSI are very similar in structure, in contact with lithium metal their decomposition products display significant differences and can therefore lead to drastic divergencies in lithium passivation and deposition behavior [4, 5]. In this study we present a comparison of LSEs containing LiFSI and/or LiTFSI. The kinetics of Solid Electrolyte Interphase (SEI) formation is investigated by Electrochemical Impedance Spectroscopy (EIS) and differences in SEI composition are discerned using X-Ray Photoelectron Spectroscopy (XPS). Resulting divergencies in SEI stability and morphology of cycled Lithium metal are being investigated by Galvanostatic Cycling and Scanning Electron Microscopy (SEM) while principal conclusions are being drawn from Nernst-Potentials and solvent complex geometries obtained by Density Functional Theory (DFT). Our results show that the main LiTFSI decomposition fragment form a SEI that is unsuitable for efficient cycling of lithium metal in a HCE. This however can be remedied by applying the LSE principle to it where the stoichiometric addition of TTE improves the electrolytes electrochemical performance, so that a stable SEI can be formed on lithium metal. Because of its comparatively high conductivity it would be advantageous to use the LiTFSI based LSE over a FSI-based one. To further enhance the LSE multiple commonly employed electrolyte additives are being considered. In this regard results from EIS, XPS and galvanostatic cycling are correlated with theoretical predictions obtained from DFT calculations. In conclusion, this study highlights the influence of TTE on the formation of the SEI in the presence of LiTFSI. The co-solvent TTE serves a double purpose: dissipating solvent-salt complexes while simultaneously acting as additive during the initial passivation phase. Further, our results show that additives, that are applied in common electrolytes do not necessarily work the same way when used in an LSE, sometimes deteriorating the SEI rather than improving it. The reason for this is that the chemical nature of a SEI significantly differs when formed from SL based electrolytes compared to ones containing 1,3-Dioxolan or ethylene carbonate. Qian J, Henderson WA, Xu W et al. (2015) High rate and stable cycling of lithium metal anode. Nat Commun 6: 6362. doi: 10.1038/ncomms7362 Ren X, Chen S, Lee H et al. (2018) Localized High-Concentration Sulfone Electrolytes for High-Efficiency Lithium-Metal Batteries. Chem 4(8): 1877–1892. doi: 10.1016/j.chempr.2018.05.002 Piwko M, Thieme S, Weller C et al. (2017) Enabling electrolyte compositions for columnar silicon anodes in high energy secondary batteries. Journal of Power Sources 362: 349–357. doi: 10.1016/j.jpowsour.2017.07.046 Howlett PC, Izgorodina EI, Forsyth M et al. (2006) Electrochemistry at Negative Potentials in Bis(trifluoromethanesulfonyl)amide Ionic Liquids. Zeitschrift für Physikalische Chemie 220(10): 1483–1498. doi: 10.1524/zpch.2006.220.10.1483 Shkrob IA, Marin TW, Zhu Y et al. (2014) Why Bis(fluorosulfonyl)imide Is a “Magic Anion” for Electrochemistry. J. Phys. Chem. C 118(34): 19661–19671. doi: 10.1021/jp506567p Figure 1

Solid state electrolytes could enable significant improvements in energy density, cycle life, and safety of next-generation battery chemistries. The ability to fabricate thin electrolyte films with high ionic conductivity and excellent stability on complex architectures has been a bottleneck to realizing a wide range of 3D structured thin film and bulk batteries. Recent progress in ALD for solid state electrolytes has shown great promise, and enabling even higher conductivities and stability with Li metal anodes could dramatically enhance the energy and power density of ALD-based batteries. In addition, ALD films with high conductivity and good stability could be used for interfacial engineering of bulk-type solid and liquid based batteries to improve stability and safety. This work demonstrates a novel ALD process for glassy lithium borate-carbonate thin films with ionic conductivities above 10-6 S/cm at 298K. This represents a 6x improvement over the previous best reported value for an ALD solid electrolyte.1 The composition, structure, and stability of the films are characterized with X-ray photoelectron spectroscopy and a range of electrochemical measurements. These experiments are compared with those calculated with Density Functional Theory and Molecular Dynamics to elucidate the origins of the high ionic conductivity and excellent stability. The properties are studied as a function of deposition temperature showing tradeoffs between process conditions and performance, and demonstrating the precise control afforded by the ALD process.2 The optimized film remains an ionic conductor when in contact with metallic Li, with no measurable changes even over several weeks, and displays stable cycling when paired with a thin-film cathode and Li metal anode. References (1) Pearse, A. J.; Schmitt, T. E.; Fuller, E. J.; El-Gabaly, F.; Lin, C. F.; Gerasopoulos, K.; Kozen, A. C.; Talin, A. A.; Rubloff, G.; Gregorczyk, K. E.; Chem. Mater. 2017, 29, 3740–3753. (2) Kazyak, E.; Chen, K. H.; Davis, A. L.; Yu, S.; Sanchez, A. J.; Lasso, J.; Bielinski, A. R.; Thompson, T.; Sakamoto, J.; Siegel, D. J.; Dasgupta, N. P.; J. Mater. Chem. A 2018, 6, 19425–19437.

In this paper, we use the occasion of the design of a learning space (The Idea Zone) in a science center setting, the Museum of Science and Industry, to illustrate the importance of attending to communication issues in the design of a process to design the space. We explore communication processes in the conceptual design phase, with specific attention to bringing Needfinding to a participatory design framework. Use of the World Cafe is made to create a conversational space for the participatory design process. We reflect on the recursive nature of designing communication process for participatory design of the Idea Zone and offer seven principles that integrate the theories and practices of both communication and design, bringing particular attention to generative metaphors, reflective practice, and emergence of a “third language” for designing together with others.

Li7La3Zr2O12 (LLZO) garnet is attracting interest as a promising Li-ion solid electrolyte. LLZO exists in a tetragonal and cubic polymorph where the cubic phase exhibits ∼2 orders of magnitude higher Li-ion conduction. It has been suggested that a critical Li vacancy concentration (0.4–0.5 atoms per formula unit) is required to stabilize the cubic polymorph of Li7La3Zr2O12. This has been confirmed experimentally for Al3+ doping on the Li+ site. Substitution of M5+ (M = Ta, Nb) for Zr4+ is an alternative means to create Li vacancies and should have the same critical Li vacancy concentration, nevertheless, subcritically doped compositions (0.25 moles of Li vacancies per formula unit) have been reported as cubic. Adventitious Al, from alumina crucibles, was likely present in these studies that could have acted as a second dopant to introduce vacancies. In this work, Al-free subcritically doped (Li6.75La3Zr1.75Ta0.25O12) and critically doped (Li6.5La3Zr1.5Ta0.5O12) compositions are investigated. X-ray diffraction indicates that both compositions are cubic. However, upon further materials characterization, including SEM analysis, Raman spectroscopy, Electrochemical Impedance Spectroscopy, and neutron diffraction it is evident that the subcritically doped composition is a mixture of cubic and tetragonal phases. The results of this study confirm that 0.4–0.5 Li vacancies per formula unit are required to stabilize the cubic polymorph of LLZO.

The influence of hierarchical TiO2 inclusions on electrical and thermal transport properties has been investigated in the Ba-filled skutterudite compound Ba0.3Co4Sb12 synthesized by ball milling followed by hot pressing. The hierarchical TiO2, with the morphology of nanocrystallite aggregates, was prepared using a carbon sphere-templated method. It was found that TiO2 inclusions strongly enhance the Seebeck coefficient while they weakly degrade the electric conductivity. In addition, TiO2 inclusions reduce significantly the lattice thermal conductivity through all-scale length phonon scattering due to the hierarchically-structured TiO2 particles. ZT values up to 1.2 were obtained for Ba0.3Co4Sb12 with an optimal amount and dispersion of TiO2 inclusions. These observations demonstrate an exciting scientific opportunity to raise the figure-of-merit of filled skutterudites via hierarchical dispersion.

Presently, the only commercially available power generating thermoelectric (TE) modules are based on bismuth telluride (Bi2Te3) alloys and are limited to a hot side temperature of 250 °C due to the melting point of the solder interconnects and/or generally poor power generation performance above this point. For the purposes of demonstrating a TE generator or TEG with higher temperature capability, we selected skutterudite based materials to carry forward with module fabrication because these materials have adequate TE performance and are mechanically robust. We have previously reported the electrical power output for a 32 couple skutterudite TE module, a module that is type identical to ones used in a high temperature capable TEG prototype. The purpose of this previous work was to establish the expected power output of the modules as a function of varying hot and cold side temperatures. Recent upgrades to the TE module measurement system built at the Fraunhofer Institute for Physical Measurement Techniques allow for the assessment of not only the power output, as previously described, but also the thermal to electrical energy conversion efficiency. Here we report the power output and conversion efficiency of a 32 couple, high temperature skutterudite module at varying applied loading pressures and with different interface materials between the module and the heat source and sink of the test system. We demonstrate a 7% conversion efficiency at the module level when a temperature difference of 460 °C is established. Extrapolated values indicate that 7.5% is achievable when proper thermal interfaces and loading pressures are used.

Acetic- and butyric-capped oleic estolide 2-ethylhexyl (2-EH) esters were synthesized in a perchloric acid catalyzed (0.05 equiv) one-pot process from industrial 90 % oleic acid and either acetic or butyric fatty acids at two different ratios. This was directly followed by the esterification process incorporated into an in-situ second step to provide a low viscosity estolide ester functional fluid. The monoestolide and polyestolides were separated via vacuum distillation (6–13 Pa) at 240–250 °C. The physical properties of these materials were followed throughout the synthetic process and are reported. The final low viscosity acetic- and butyric-capped monoestolide 2-EH esters had viscosities of 19.9 and 24.2 cSt at 40 °C and 4.8 and 5.5 cSt at 100 °C with viscosity indexes (VI) of 161 and 163, respectively. Both monoestolide esters displayed excellent pour points (PPs). The PPs of the two were as follows: acetic-capped estolide 2-EH ester PP = −45 °C and butyric-capped estolide 2-EH ester PP = −27 °C. The biodegradable short-capped oleic estolide 2-EH esters had excellent low temperature properties and should perform well in low viscosity applications.

Vegetable oil-based oils usually fail to meet the rigorous demands of industrial lubricants by not having acceptable low temperature properties, pour point (PP) and/or cloud point (CP). Oleic estolide was produced from oleic fatty acid and a catalytic amount of perchloric acid. The oleic estolide was then esterified with a series of 16 different alcohols that were either branched or linear-chained. The new estolide esters physical properties were recorded and evaluated as a potential industrial lubricant. The linear-chain esters had higher low temperature properties (PP = −9 to −33 °C) but still compete well with other commercial bio-based materials. The oleic estolide ethyl ester yielded the best PP at −33 °C for the linear-chain series. The branched alcohol produced the best PP (−24 to −39 °C) and CP (−30 to