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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,009 records · Page 56
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Polymer Solar Cells with 18.74% Efficiency: From Bulk Heterojunction to Interdigitated Bulk Heterojunction

The most popular approach to fabricating organic solar cells (OSCs) is solution processing a mixture of donor (D) and acceptor (A) materials into an active layer with a bulk heterojunction (BHJ) nanostructure. In this work, it is demonstrated that the interdigitated heterojunction (IHJ) is a more suitable nanostructure of the active layer for high-performance OSCs whereas it is a long standing challenge to realize well-defined IHJ structures. Here, a facile and versatile sequential solution processing method is developed to produce an IHJ nanostructure with power conversion efficiency reaching 18.74% (18.10% for BHJ the counterpart) by fabricating a donor film with nanopores created by a wax additive, sequentially casting the acceptor on top of infiltrating the nanopores. Compared to the BHJ, the IHJ structure with an interpillar distance within the exciton diffusion length can afford a large bulk D/A interface for efficient exciton dissociation with a minimized charge recombination while free electrons and holes can transport to the respective electrodes through more straightforward pathways, thus enhance performance. Furthermore, the D or A phase in the IHJ device contacts with only one electrode, which can prevent shunting between the anode and cathode and facilitate the industrial mass production of OSCs.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Impact of Electrolyte Composition on Bulk Electrolysis of Furfural over Platinum Electrodes

Partial oxidation of furanic biomass derivatives such as furfural is of interest for the sustainable production of chemicals including furoic acid, maleic acid, and 2,5-furandicarboxylic acid (FDCA). The oxidative bulk electrolysis of furfural is here investigated on platinum electrodes in acidic media. The effects of potential, concentration, pH, and supporting anion are studied, and selectivity trends are coupled with attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) to illuminate adsorbate structures that influence the catalysis. Increasing potential is found to shift selectivity from primarily C 5 products to C 4 products, coincident with oxidation of the Pt surface. Selectivity changes are also observed moving from pH 1 to pH 4, with an increase in C 5 products at higher pH. Furthermore, changing from the weakly adsorbing perchlorate anion to the specifically-adsorbing phosphate anion results in a number of changes that manifest differently depending on potential and pH. Selectivity to furoic acid is found to be highest above the pKa of phosphoric acid due to the strongly adsorbed phosphate ions suppressing flat-lying configurations of furfural that lead to C−C cleavage. These results point toward opportunities to use electrolyte engineering to tune selectivity and optimize surface conditions to disfavor binding of inhibitory products.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

A Guide to Nonaqueous Electrochemistry of f-Element Complexes

Electrochemistry is a powerful tool for assessing and understanding the redox chemistry of molecular complexes. Cyclic voltammetry enables the f-element community to study molecules in unusually high or low oxidation states, which potentially pose important broad-scope questions of electronic structure. In the pursuit of boundary-pushing compounds, reactive air- and moisture-sensitive species are often encountered, which can be challenging to characterize, especially when they are chemically incompatible with certain solvents, electrolytes, or electrodes or when their potentials lie outside of common electrochemical windows. Nonaqueous solvents and pseudo reference electrodes complicate many of the standard practices in acquiring high-quality and reproducible electrochemical data. This guide presents a detailed discussion of selecting appropriate cell conditions and referencing and addresses metrics for evaluating electrochemical and chemical reversibility. These methodological approaches have been extended to best practices for the electrochemical analysis of radioactive transuranic complexes.

Electrodes↗
DOE OSTI2025

Amino Acid Sequence Controls Enhanced Electron Transport in Heme-Binding Peptide Monolayers

Metal-binding proteins have the exceptional ability to facilitate long-range electron transport in nature. Despite recent progress, the sequence-structure–function relationships governing electron transport in heme-binding peptides and protein assemblies are not yet fully understood. In this work, the electronic properties of a series of heme-binding peptides inspired by cytochrome bc1 are studied using a combination of molecular electronics experiments, molecular modeling, and simulation. Self-assembled monolayers (SAMs) are prepared using sequence-defined heme-binding peptides capable of forming helical secondary structures. Following monolayer formation, the structural properties and chemical composition of assembled peptides are determined using atomic force microscopy and X-ray photoelectron spectroscopy, and the electronic properties (current density–voltage response) are characterized using a soft contact liquid metal electrode method based on eutectic gallium–indium alloys (EGaIn). Our results show a substantial 1000-fold increase in current density across SAM junctions upon addition of heme compared to identical peptide sequences in the absence of heme, while maintaining a constant junction thickness. These findings show that amino acid composition and sequence directly control enhancements in electron transport in heme-binding peptides. Overall, this study demonstrates the potential of using sequence-defined synthetic peptides inspired by nature as functional bioelectronic materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Detecting lithium plating dynamics in a solid-state battery with operando X-ray computed tomography using machine learning

Operando X-ray micro-computed tomography (µCT) provides an opportunity to observe the evolution of Li structures inside pouch cells. Segmentation is an essential step to quantitatively analyzing µCT datasets but is challenging to achieve on operando Li-metal battery datasets due to the low X-ray attenuation of the Li metal and the sheer size of the datasets. Herein, we report a computational approach, batteryNET, to train an Iterative Residual U-Net-based network to detect Li structures. The resulting semantic segmentation shows singular Li-related component changes, addressing diverse morphologies in the dataset. In addition, visualizations of the dead Li are provided, including calculations about the volume and effective thickness of electrodes, deposited Li, and redeposited Li. We also report discoveries about the spatial relationships between these components. The approach focuses on a method for analyzing battery performance, which brings insight that significantly benefits future Li-metal battery design and a semantic segmentation transferrable to other datasets.

25 ENERGY STORAGE↗
DOE OSTI2022

High current density electroreduction of CO 2 into formate with tin oxide nanospheres

In this study, we demonstrate three-dimensional (3D) hollow nanosphere electrocatalysts for CO 2 conversion into formate with excellent H-Cell performance and industrially-relevant current density in a 25 cm 2 membrane electrode assembly electrolyzer device. Varying calcination temperature maximized formate production via optimizing the crystallinity and particle size of the constituent SnO 2 nanoparticles. The best performing SnO 2 nanosphere catalysts contained ~ 7.5 nm nanocrystals and produced 71–81% formate Faradaic efficiency (FE) between -0.9 V and -1.3 V vs. the reversible hydrogen electrode (RHE) at a maximum formate partial current density of 73 ± 2 mA cm geo -2 at -1.3 V vs. RHE. The higher performance of nanosphere catalysts over SnO 2 nanoparticles and commercially-available catalyst could be ascribed to their initial structure providing higher electrochemical surface area and preventing extensive nanocrystal growth during CO 2 reduction. Our results are among the highest performance reported for SnO 2 electrocatalysts in aqueous H-cells. We observed an average 68 ± 8% FE over 35 h of operation with multiple on/off cycles. In situ Raman and time-dependent X-ray diffraction measurements identified metallic Sn as electrocatalytic active sites during long-term operation. Further evaluation in a 25 cm 2 electrolyzer cell demonstrated impressive performance with a sustained current density of 500 mA cm geo -2 and an average 75 ± 6% formate FE over 24 h of operation. Our results provide additional design concepts for boosting the performance of formate-producing catalysts.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Large-area low-noise flexible organic photodiodes for detecting faint visible light

Silicon photodiodes are the foundation of light-detection technology; yet their rigid structure and limited area scaling at low cost hamper their use in several emerging applications. A detailed methodology for the characterization of organic photodiodes based on polymeric bulk heterojunctions reveals the influence that charge-collecting electrodes have on the electronic noise at low frequency. The performance of optimized organic photodiodes is found to rival that of low-noise silicon photodiodes in all metrics within the visible spectral range, except response time, which is still video-rate compatible. Solution-processed organic photodiodes offer several design opportunities exemplified in a biometric monitoring application that uses ring-shaped, large-area, flexible, organic photodiodes with silicon-level performance.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

Electromagnetic Energy-Assisted Thermal Conversion of Fossil-Based Hydrocarbons to Low-Cost Hydrogen

The goal of this project was to develop and optimize catalysts for methane decomposition, particularly focusing on regeneration via an electromagnetic energy-assisted mechanism, to produce hydrogen more cost-effectively compared to electrolysis routes. To achieve this goal, the project pursued several key objectives. The project began with the preparation and testing of various catalysts. A nickel-silica based catalyst was identified as the most promising material for the pyrolysis of methane into carbon and hydrogen. Kinetic parameters for methane decomposition were determined, aiding in computational modeling efforts. Structured catalysts were investigated, highlighting the need for frequent cleaning or regeneration to maintain performance, with methane conversion rates exceeding 70% in tube furnace tests. Computational fluid dynamics modeling was employed to optimize reactor designs and electrode angles, leading the project team to propose a multi-compartment thermal conversion system for larger setups. This modeling work was important in understanding reaction characteristics, carbon deposition rates, and temperature profiles under various conditions. A bench-scale reactor system was assembled to evaluate catalyst regeneration using electromagnetic energy-assisted mechanisms. Experiments demonstrated the potential for carbon removal, though further optimization is needed. The carbon produced from the methane conversion process was evaluated for potential use in lithium-ion battery electrodes. The carbon exhibited properties similar to commercially available high-purity multi-walled carbon nanotubes and nanofibers, with a carbon content greater than 95%. Coin cell batteries assembled with this carbon showed that lower replacement levels (10% to 33%) outperformed the control group, improving specific capacity density and stability. However, higher replacement levels (100%) demonstrated poorer performance, suggesting that excessive carbon substitution negatively impacts battery performance. These findings indicate the potential marketability of the produced carbon as a component in lithium-ion batteries, though further testing is necessary to confirm long-term advantages and disadvantages associated with the use of the carbon product. These results however justified further technoeconomic assessments to determine if the process can provide low-cost hydrogen. The economic feasibility and technical performance of methane decomposition for hydrogen production were assessed, focusing on three plant configurations: 100E (electrically heated), 100C (combustion heated using produced hydrogen), and PE-Hybrid (a combination of pyrolysis (indicating decomposition) and electrolysis). The Levelized Cost of Hydrogen (LCOH) for the pyrolysis configurations was found to be approximately 25% lower than that of electrolysis. The 100E configuration had the lowest LCOH at $\$$3.12/kg. Including carbon product sales significantly improved the economics, with the 100C configuration achieving a negative LCOH of -$\$$0.35/kg. The PE-Hybrid configuration was not economically advantageous compared to pure pyrolysis plants due to its complexity and additional equipment requirements. Ultimately, methane pyrolysis presents a viable method for near carbon dioxide-free hydrogen production, with significant economic advantages over electrolysis, especially when considering the sale of carbon byproducts. The 100E and 100C configurations showed the most promise, with the choice between them ultimately depending on the prices of power and natural gas. In conclusion, this technology has the potential to lower hydrogen production costs by leveraging the methane decomposition process with the sale of valuable carbon byproducts. By optimizing catalyst performance and integrating electromagnetic energy-assisted regeneration, the process can achieve higher efficiency and economic viability, making it a competitive alternative to traditional hydrogen production methods.

08 HYDROGEN↗
DOE OSTI2024

Flexible Soft X-Ray Image Sensors based on Metal Halide Perovskites With High Quantum Efficiency

Soft X-ray imaging is a powerful tool to explore the structure of cells, probe material with nanometer resolution, and investigate the energetic phenomena in the universe. Conventional soft X-ray image sensors are by and large Si-based charge coupled devices that suffer from low frame rates, complex fabrication processes, mechanical inflexibility, and required cooling below -60 °C. Here, a soft X-ray photodiode is reported based on low-cost metal halide perovskite with comparable performance to commercial Si-based device. Nanothrough network electrode minimized the optical loss due to the shadowing of insensitive layers, while a multidimensional perovskite heterojunction is generated to reduce the photo-generated carrier loss. Further, this strategy promoted a record quantum efficiency of 8 × 10 3 % without cooling, several orders of magnitude greater than the previously achieved. Flexible and curved soft X-ray imaging arrays are fabricated based on this high-performance device structure, demonstrating stable soft X-ray response and sharp imaging capabilities. This work highlights the low-cost and efficient perovskite photodiode as a strong candidate for the next-generation soft X-ray image sensors.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Optically Induced Picosecond Lattice Compression in the Dielectric Component of a Strongly Coupled Ferroelectric/Dielectric Superlattice

Above-bandgap femtosecond optical excitation of a ferroelectric/dielectric BaTiO 3 /CaTiO 3 superlattice leads to structural responses that are a consequence of the screening of the strong electrostatic coupling between the component layers. Time-resolved X-ray free-electron laser diffraction shows that the structural response to optical excitation includes a net lattice expansion of the superlattice consistent with depolarization-field screening driven by the photoexcited charge carriers. The depolarization-field-screening-driven expansion is separate from a photoacoustic pulse launched from the bottom electrode on which the superlattice is epitaxially grown. The distribution of diffracted intensity of superlattice X-ray reflections indicates that the depolarization-field-screening-induced strain includes a photoinduced expansion in the ferroelectric BaTiO 3 and a contraction in CaTiO 3 . The magnitude of expansion in BaTiO 3 layers is larger than the contraction in CaTiO 3 . The difference in the magnitude of depolarization-field-screening-driven strain in the BaTiO 3 and CaTiO 3 components can arise from the contribution of the oxygen octahedral rotation patterns at the BaTiO 3 /CaTiO 3 interfaces to the polarization of CaTiO 3 . The depolarization-field-screening-driven polarization reduction in the CaTiO 3 layers points to a new direction for the manipulation of polarization in the component layers of a strongly coupled ferroelectric/dielectric superlattice.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Cellulose regulated lignin/cellulose-based carbon materials with hierarchical porous structure for energy storage

Lignin has gained extensive attention as an ideal carbon precursor due to its abundance and high carbon content. However, the agglomeration of lignin and additional corrosive and unrecyclable reagents in direct pyrolysis still limit the development of lignin-based porous carbons. Herein, a facile and eco-friendly strategy was proposed to fabricate hierarchical porous lignin/cellulose-based carbon materials (LCs). In the process, cellulose nanofibrils acted as the skeleton of the bio-aerogels, which supported lignin and benefit the preparation of the LCs. Moreover, the specific surface area and the graphitization degree of LCs can be regulated by varying the cellulose content. Without activation, the bio-based carbon material (LC30) had a high specific surface area of 1770 m 2 g –1 , which displayed high specific capacitance of 216.2 F g –1 at the current density of 0.5 A g –1 . The supercapacitor based on LC30 also showed outstanding energy density of 12.3 Wh kg –1 at the power density of 50 W kg –1 . The sustainable raw material, simple and harmless preparation process, and remarkable electrochemical performance enable LC30, a promising supercapacitor electrode for energy storage.

25 ENERGY STORAGE↗
DOE OSTI2026

Dispersion of high oxygen permeability ionomers in water-propanol solutions

There is a growing interest in high oxygen permeability ionomers (HOPI) for better-performing proton exchange membrane fuel cell (PEMFC) catalyst layers. In this study, we used small-angle x-ray scattering (SAXS) to analyze dispersions of two types of perfluorinated sulfonic acid (PFSA) ionomers and a HOPI in water and propanol solvents, at concentrations between 1 wt% and 15 wt%. HOPI dispersions exhibited the interference peak typical of ionomers; by separately fitting the peak and higher- q regions with several models, we demonstrated that HOPI aggregates have a closer average spacing than conventional PFSA ionomers, and smaller aggregate size when assuming a cylindrical geometry. By measuring conventional PFSA ionomers with two side chain lengths and several equivalent weights, we showed that these side chain parameters alone did not explain the differences in aggregate spacing or size. In addition, the pattern was present whether samples were prepared in a 50/50 water/propanol or a more propanol-rich mixture. As such, the structural differences of HOPI could be due to its different backbone monomer. A better understanding of the influence of the HOPI chemistry on dispersion properties could help explain the ink structure and drying characteristics of HOPI observed in prior work. Future study of ionomer-catalyst mixtures, such as measuring ionomer adsorption to carbon, would help elucidate the role of ionomer from ink formulation to the cast electrode.

Aquivion↗
DOE OSTI2026

Cobalt-Doped Tungsten Oxide Nanoparticles for Electrochemical Sensing and Detection of a Penicillin Antibiotic: Amoxicillin

A sensitive electrochemical sensor for the determination of antibacterial amoxicillin (AMXL) in pharmaceutical dosage and environmental samples was developed, since its residues were found in water, food, and biological samples to pose adverse health risks such as immune–allergic reactions and antimicrobial resistance. WO 3 -based sensors are reported to provide higher sensitivity, selectivity, and stability during the electrochemical reaction. Considering this, Co-doped WO 3 nanostructures were synthesized by the hydrothermal method yielding a mixture of nanoparticle and nanorod structures and applied to the assay of AMXL. Extensive characterizations were carried out by SEM, XRD, TEM, and XPS analysis that confirm the monoclinic crystal structure with a uniform Co distribution in the WO 3 lattice. The optimum doping amount of Co in the lattice is found to be 1.80 at %. The electrochemical performance of the Co-WO 3 /carbon paste electrode (CPE) was evaluated for the determination of AMXL under optimum conditions using cyclic voltammetry, electrochemical impedance spectroscopy, and square wave voltammetry. The Co-WO 3 /CPE showed two linear detection ranges at 0.01–0.1 μM with the linear regression I pa = 3.73 [AMXL] + 0.77 with R 2 = 0.96 and at 0.1 to 30.0 μM with the linear regression I pa = 3.76 [AMXL] + 0.69 with R 2 = 0.95. The limit of detection was 9.1 nM (SNR = 3), and the limit of quantification was 30.6 nM (SNR = 10). The sensitivities for lower and higher concentration ranges were 63.22 and 63.73 μA μM –1 cm –2 , respectively. Furthermore, Co-WO 3 /CPE showed high selectivity and anti-interference capabilities. In conclusion, the sensing and disposable Co-WO 3 /CPE sensor showed a great potential for AMXL analysis in spiked soil, water, and Amoxil tablet samples with desirable percentage recovery.

Shanbhag, Mahesh M. [KLE Technological University,↗
DOE OSTI2026

Synthesis of NiRu-Layered Double Hydroxide for Enhanced Oxygen Evolution Reaction

Nickel−ruthenium layered double hydroxide (NiRu-LDH) was synthesized by coprecipitation using formamide as both solvent and intercalant. The synthesis was performed at various temperatures to study the impact of temperature on electrochemical performance. Temperature plays a vital role in optimizing LDH synthesis to enhance oxygen evolution reaction (OER) efficiency. The optimal temperature yielded a well-defined morphology with balanced crystallinity, leading to more active sites and improved charge transfer. Electrochemical tests indicated that the NiRu-LDH sample prepared at 50 °C (NiRu-LDH-50) required only 280 mV overpotential versus the reversible hydrogen electrode to achieve 10 mA/cm 2 and exhibited a low Tafel slope of 52 mV/dec, demonstrating excellent catalytic kinetics. This study presents the synthesis of NiRu-LDH via coprecipitation and emphasizes how reaction temperature influences LDH structural properties and OER performance.

Catalysts↗
DOE OSTI2021

An open-endcap blade trap for radial-2D ion crystals

We present the design and experimental demonstration of an open-endcap radio frequency trap to confine ion crystals in the radial-two dimensional (2D) structural phase. The central axis of the trap is kept free of obstructions to allow for site-resolved imaging of ions in the 2D crystal plane, and the confining potentials are provided by four segmented blade electrodes. We discuss the design challenges, fabrication techniques, and voltage requirements for implementing this open-endcap trap. Finally, we validate its operation by confining up to 29 ions in a 2D triangular lattice, oriented such that both in-plane principal axes of the 2D crystal lie in the radial direction.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2023

Self-assembly of co-continuous nanostructured copolymer templates with compositional and architectural dispersity

In our previous DOE-supported project (DE-SC0016208), we demonstrated that a particular architecture dubbed ‘randomly end-linked copolymer networks’ (RECNs) led to especially robust self-assembly of disordered cocontinuous nanostructures. Such structures, wherein both microphases are fully percolating in three dimensions, are attractive for a wide-variety of energy-relevant applications including purification membranes, separators in batteries and fuel cells, catalyst supports, and high surface area electrodes. In the current project we sought to substantially extend our fundamental understanding of how different types of randomness in blocky copolymer architecture contribute to the robust formation of disordered cocontinuous nanostructures. To do so, we filled in the sizable gap between the previously studied cases of randomly linked linear multiblock copolymers and RECNs by studying two intermediate cases: (i) random miktoarm star polymers, which contain dispersity in the number of the two chemically-incompatible strands located at each junction and therefore the preferred interfacial curvature of each polymer, and (ii) randomly branched copolymers, which also possess bridging strands that stretch across domains and apply local ‘elastic’ forces to the interfaces. In addition, we studied a different network architecture, statistically crosslinked copolymer networks, that is more straightforward to prepare using chain growth polymerization methods, enabling more facile formation of cocontinuous nanostructures. Finally, we extended our approaches from model systems based on polystyrene and poly(lactic acid) to copolymer architectures containing either (i) polysulfone, an engineering polymer that provides excellent mechanical properties for membrane applications, or (ii) polyacrylonitrile, providing a convenient route to nanoporous carbon materials.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Multi-layer anodes for high-current applications

In this work, we present a combination of experiments and modeling of a two-layer anode structure designed by EnPower Inc. for high-energy and fast-charge capabilities. The anode consists of lower porosity near the current collector and higher porosity near the separator with comparable active materials in both regions. A pseudo-two-dimensional electrochemical–thermal model was designed to represent the performance of this electrode. Simulations, consistent with experiments, show superior ion transport and lithiation in the multi-layer anode (MLA) compared to a conventional single-layer anode (SLA). Surprisingly, this improved transport in MLA manifests as enhanced cathode performance during high-rate discharge and this, in turn, provides higher energy density for MLA. Similarly, during fast charge, less irreversible lithium is deposited due to this improved transport in MLA, and hence MLA exhibits less capacity fade compared to SLA. Polarization analysis demonstrates marginally lower cumulative overpotential for MLA in different case studies; however, MLA cells maintain a significantly higher capacity in the same conditions and have more than double the cycle life. Further, this means despite the apparently limited polarization benefit provided by MLA; the MLA structure can more reliably be employed in cell designs. Additional design changes are also analyzed by means of the model.

25 ENERGY STORAGE↗
DOE OSTI2021

Toward the Development of a High-Voltage Mg Cathode Using a Chromium Sulfide Host

Development of Mg-ion batteries as advanced electrochemical energy storage systems relies on the design and discovery of high-voltage positive electrode (cathode) materials. To date, a variety of sulfide cathodes have been reported (e.g., Mg x Mo 6 S 8 , Mg x Ti 2 S4, etc.), but the voltages of these materials are too low to prepare a high energy density Mg cell. Theoretical computations predicted that Mg x Cr 2 S 4 operating with the high-voltage Cr 3+/4+ redox couple would serve as a suitable cathode candidate, but experimental attempts to extract Mg 2+ from the lattice have been largely unsuccessful. Here, we show that reversible electrochemical activity within a thiospinel framework (AB 2 S 4 ) relies on a redox-active transition metal present in the B site; otherwise, anionic redox activity triggers decomposition of the spinel structure. Since Cr and S states are highly coupled in MgCr 2 S 4 , the Cr 3+/4+ redox couple is inaccessible so that reversible (de)intercalation of Mg 2+ cannot occur and charging leads to dissolution of the active material. These findings point to an insufficiency in the screening criteria previously used to identify MgCr 2 S 4 as a promising Mg cathode. Thus, a computable descriptor based on the electronic structure of the discharged material is proposed to predict the prevalence of cation vs anion redox and improve future surveys of potential candidates. It is unlikely that the high-voltage Cr redox couple will be accessible to oxidation in the presence of sulfur within the restrictions of a spinel framework; however, it is possible that a suitable layered Mg x CrS 2 structure could serve as a reversible high-voltage Mg cathode.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗