Hydraulic and biological characterization of a large Kaplan turbine
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Martinez, J. J. (ORCID:0000000208705537)↗
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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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The "Perfect Storm" for Distributed Wind Markets
Close to 1 GW of distributed wind has been installed across all 50 states, the District of Columbia, Puerto Rico, and the U.S. Virgin Islands. Yet the number of installations varies greatly by state, even when wind resources are similar. This article examines three key factors that over the past thirteen years have shown to be enablers of success for distributed wind installations in the United States: 1) favorable policy environments, including consistent incentives, administrative support for cutting through red tape, and favorable interconnection, net metering, and permitting policies; 2) high electricity prices that would be displaced by wind energy generation, and, 3) favorable wind resources, enabling steady production of energy. Not all conditions need to be met simultaneously, yet of the studied markets for distributed wind in Iowa, New York, Washington, and Oregon, the most successful ones exhibit at least two out of the three conditions mentioned. We describe steps that policymakers, regulators, and market players have taken in the past to increase distributed wind installations in the United States.
Foster, Nikolas AF↗
Hydrokinetic tidal energy resource assessment following international electrotechnical commission guidelines
Marine renewable energy can be used as a viable energy source to alleviate the impact of the climate crisis and have a carbon-free electricity sector in the future. Especially the energetic tidal streams are an attractive source of clean energy due to the periodic occurrence of high tidal flows daily. However, before any deployment of tidal turbine farms, it is essential to perform a resource assessment depending on the scope and scale of the project. Here, the International Electrotechnical Commission has developed a technical standard for assessing the tidal stream resource "IEC 62600-201 TS" to aid in this effort: determine a particular site's feasibility and perform the project layout design. In this study, we implemented and validated a high-resolution three-dimensional numerical model and provided results following the IEC TS for a project layout design in a highly energetic tidal channel, Tacoma Narrows of Puget Sound, in the State of Washington, USA. Implementation of the guidelines has helped adequately identify the undisturbed theoretical and technical resources with less bias, where the latter included energy extraction from the flow field arranging a hypothetical tidal energy converter (TEC) array. Also, following the standard, we carefully assessed the changes to channel flow properties from TECs, such as the kinetic energy flux and annual energy production (AEP), to provide the detailed information required for a larger project layout design. Ultimately, this work has shown the important role of IEC TS in tidal stream resource assessment, which can simultaneously act as a benchmark for other studies worldwide.
13 HYDRO ENERGY↗
Calcareous organic matter coatings sequester siderophores in alkaline soils
Although most studies on organic matter stabilization in soils have focused on adsorption to aluminosilicate and iron oxide minerals due to their strong interactions with organic nucleophiles, stabilization within alkaline soils has been empirically correlated with exchangeable Ca concentrations. Yet the extent of competing processes within natural soil remain unclear. We employed sub-micron scale techniques to investigate the minerology and organic carbon on individual fine particles within an alkaline soil from Eastern Washington. XRD, Mössbauer spectroscopy, TEM-EDX-SAED, and XPS analysis demonstrated a mineral assemblage dominated by quartz, feldspars, iron oxides, and calcite. Although exposed Si, Al, and Fe accounted for ~30% of the surface elemental composition, most of the organic carbon and nitrogen was associated with Ca-rich coatings. Adsorption isotherms of two siderophores with the same soil showed greater adsorption of pyoverdine compared with less polar enterobactin. Using NanoSIMS to map the distribution of isotopically labeled siderophores across the surfaces of fine grains, we observed a preference for binding to surfaces heavily coated with organic matter. We propose a mechanism of adsorption by which organic molecules aggregate within calcareous soils via calcium bridging, favoring the stabilization of larger molecules with a greater number of nucleophilic functional groups.
54 ENVIRONMENTAL SCIENCES↗
Capacity contributions of Southern Oregon offshore wind to the Pacific Northwest and California
Variable renewable energy generation poses unique capacity challenges, which increasingly depend on weather events at varying timescales. Facilitated by transmission planning, geographic and technological diversity of the generation fleet may provide a mitigation to capacity shortfalls. In this work, offshore wind (OSW) energy is sited in the areas off the West Coast between Coos Bay, Oregon, and Crescent City, California. Three generation and transmission scenarios are modeled within the Western Interconnection: (i) 3.4 gigawatts (GW) of installed OSW capacity connected to Southern Oregon through a High Voltage Alternating Current (HVAC) Radial Topology in 2030; (ii) 12.9 GW of installed OSW capacity connected to Washington, Oregon, and California through a High Voltage Direct Current (HVDC) Radial Topology post-2030, and (iii) the same 12.9 GW connected to the same locations through a Multi-terminal DC (MTDC) Backbone Topology post-2030. Zonal dispatch simulations assuming coincident wind, solar, and hydropower production and loads over 18 meteorological years, accounting for temperature-dependent equipment derating and forced outages, serve as inputs to the Associated System Capacity Contribution (ASCC) methodology. The capacity credit is 33%, 25% and 34% for the 2030 HVAC Radial Topology, 2030+ HVDC Radial Topology, and 2030+ MTDC Backbone Topology, respectively. Transmission design is shown to mitigate the typical erosion of marginal capacity contribution as more OSW is developed, underscoring the opportunity for grid modernization while decarbonizing the generation mix.
17 WIND ENERGY↗
First-principles characterization of formate and carboxyl adsorption on the stoichiometric CeO2(111) and CeO2(110) surfaces
Molecular adsorption of formate and carboxyl on the stoichiometric CeO2(111) and CeO2(110) surfaces was studied using periodic density functional theory (DFT+U) calculations. Two distinguishable adsorption modes (strong and weak) of formate are identified. The bidentate configuration is more stable than the monodentate adsorption configuration. Both formate and carboxyl bind at the more open CeO2(110) surface are stronger. The calculated vibrational frequencies of two adsorbed species are consistent with experimental measurements. Finally, the effects of U parameters on the adsorption of formate and carboxyl over both CeO2 surfaces were investigated. We found that the geometrical configurations of two adsorbed species are not affected by using different U parameters (U=0, 5, and 7). However, the calculated adsorption energy of carboxyl pronouncedly increases with the U value while the adsorption energy of formate only slightly changes (<0.2 eV). The Bader charge analysis shows the opposite charge transfer occurs for formate and carboxyl adsorption where the adsorbed formate is negatively charge whiled the adsorbed carboxyl is positively charged. Interestingly, with the increasing U parameter, the amount of charge is also increased. This work was supported by the Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL) and by a Cooperative Research and Development Agreement (CRADA) with General Motors. The computations were performed using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington. Part of the computing time was also granted by the National Energy Research Scientific Computing Center (NERSC)
adsorption↗
Atomic-scale Imaging of PGM-free Catalyst Active Sites by 30 keV 4D-STEM
Platinum group metal (PGM)-free catalysts have attracted a large amount of attention due to their potential for enabling low-cost, commercially viable hydrogen fuel cells and electrolyzers [1]. Degradation of cell performance remains a significant challenge, however, currently limiting implementation of devices that utilize PGM-free materials [2]. Controlling degradation in these materials requires a better understanding of the atomic structure of active sites, thought to be FeN4 structures within a graphitic carbon lattice, which would enable more accurate prediction of the associated degradation pathways. The exact structural arrangement of active sites in these materials is still debated since a range of structures have been computationally predicted and methods to directly validate these models are still needed [1,3-5].While scanning transmission electron microscopy (STEM) has provided initial glimpses into the nature of the proposed active sites, detailed evaluation of the structure of these sites is challenging since they involve defects, edges, and nitrogen dopants in the graphitic lattice, which are susceptible to beam damage [6,7]. Conventional STEM imaging and spectroscopy methods exacerbate this problem with dose-inefficiency or nonideal contrast characteristics for imaging light and heavy elements simultaneously. A method that minimizes damage while generating dose-efficient, easily-interpretable contrast for both light and heavy elements is therefore needed to facilitate imaging of sensitive active site atomic structure.Here, we demonstrate direct atomic-scale imaging of PGM-free catalyst active sites by low-voltage four-dimensional (4D)-STEM. To accomplish this, we pair a 30 keV aberration-corrected probe, which minimizes knock-on damage, with a fast pixelated detector that has optimal performance at low beam energies [8]. We show how this setup enables relatively simple center-of-mass (CoM) techniques [9,10] to produce images with an increased signal-to-noise ratio (SNR) and light-element contrast over conventional imaging modes, allowing the entire active site structure to be imaged at the atomic scale. Moreover, we show how electron ptychography [11,12] enables images with further improved characteristics to be obtained, for example by minimizing residual aberrations, which provides a more accurate structural representation. The increased understanding that these low-voltage 4D-STEM techniques will provide about the atomic structure of PGM-free active sites and their associated degradation pathways will facilitate rational design of next-generation materials, promoting development of low-cost hydrogen fuel cells, electrolyzers, and other energy conversion devices [13]. References:[1] U Martinez et al., Adv. Mater. 31 (2019), p. 1806545.[2] Y Shao et al., Adv. Mater. 31 (2019), p. 1807615.[3] J Kneebone et al., J. Phys. Chem. C 121, (2017), p.16283.[4] T Mineva et al., ACS Catal. 9 (2019), p. 9359.[5] J Li et al., Nat. Catal. 4 (2021), p. 10.[6] T Susi et al., ACS Nano 6 (2012), p. 8837.[7] P Zelenay and DJ Myers, US Department of Energy Hydrogen and Fuel Cells Program 2017 Annual Merit Review and Peer Evaluation Meeting, Washington, DC (2017).[8] H Ryll et al., J. Inst. 11 (2016), p. P04006.[9] K Müller et al., Nat. Commun. 5 (2014), p. 5653.[10] I Lazic et al., Ultramicroscopy 160 (2016), p. 265.[11] H Yang et al., Nat. Commun. 7 (2016), p. 12532.[12] Y Jiang et al., Nature 559 (2018), p. 343. [13] Research sponsored by the Hydrogen and Fuel Cell Technologies Office, Office of Energy Efficiency and Renewable Energy, US Department of Energy (DOE). Research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.
Zachman, Michael↗
Peptoid Backbone Flexibilility Dictates Its Interaction with Water and Surfaces: A Molecular Dynamics Investigation
Peptoids are peptide-mimetic biopolymers that are easy-to-synthesize and adaptable for use in drugs, chemical scaffolds, and coatings. However, there is insufficient information about their structural preferences and interactions with the environment in various applications. We conducted a study to understand the fundamental differences between peptides and peptoids using molecular dynamics simulations with semi-empirical (PM6) and empirical (AMBER) potentials, in conjunction with metadynamics enhanced sampling. From studies of single molecules in water and on surfaces, we found that sarcosine (model peptoid) is much more flexible than alanine (model peptide) in different environments. However, the sarcosine and alanine interact similarly with a hydrophobic or a hydrophilic. Finally, this study highlights the conformational landscape of peptoids and the dominant interactions that drive peptoids towards these conformations. ACKNOWLEDGMENT: MD simulations and manuscript preparation were supported by the MS3 (Materials Synthesis and Simulation Across Scales) Initiative at Pacific Northwest National Laboratory (PNNL), a multi-program national laboratory operated by Battelle for the U.S. Department of Energy. CJM was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences Division of Chemical Sciences, Geosciences, and Biosciences. MDB was supported by the US Department of Energy, Office of Basic Energy Sciences, Biomolecular Materials Program at PNNL. Computing resources were generously allocated by University of Washington's IT department and PNNL's Institutional Computing program. The authors greatly acknowledge conversations with Dr. Kayla Sprenger, Josh Smith, and Dr. Yeneneh Yimer.
alanine↗
Efficient Capture of Perrhenate and Pertechnetate by a Mesoporous Zr Metal–Organic Framework and Examination of Anion Binding Motifs
At the Hanford Site in southeastern Washington state, the U.S. Department of Energy intends to treat 56 million gallons of legacy nuclear waste by encasing it in borosilicate glass via vitrification. This process ineffectively captures radioactive pertechnetate (TcO 4 –) because of the ion’s volatility, thereby requiring a different remediation method for this long-lived (t 1/2 = 2.1 × 10 5 years), environmentally mobile species. Currently available sorbents lack the desired combination of high uptake capacity, fast kinetics, and selectivity. Here, we evaluate the ability of the chemically and thermally robust Zr 6 -based metal–organic framework (MOF), NU-1000, to capture perrhenate (ReO 4 –), a pertechnetate simulant, and pertechnetate. Our material exhibits an excellent perrhenate uptake capacity of 210 mg/g, reaches saturation within 5 min, and maintains perrhenate uptake in the presence of competing anions. Additionally, experiments with pertechnetate confirm perrhenate is a suitable surrogate. Single-crystal X-ray diffraction indicates both chelating and nonchelating perrhenate binding motifs are present in both the small pore and the mesopore of NU-1000. Postadsorption diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) further elucidates the uptake mechanism and powder X-ray diffraction (PXRD) and Brunauer–Emmett–Teller (BET) surface area analysis confirm the retention of crystallinity and porosity of NU-1000 throughout adsorption.
36 MATERIALS SCIENCE↗
Quantification of CO 2 Mineralization at the Wallula Basalt Pilot Project
In 2013, the Pacific Northwest National Laboratory led a geologic carbon sequestration field demonstration where ~1000 tonnes of CO 2 was injected into several deep Columbia River Basalt zones near Wallula, Washington. Rock core samples extracted from the injection zone two years after CO 2 injection revealed nascent carbonate mineralization that was qualitatively consistent with expectations from laboratory experiments and reactive transport modeling. In this study, we report on a new detailed analysis of the 2012 pre-injection and 2015 post-injection hydrologic tests that capitalizes on the difference in fluid properties between scCO 2 and water to assess changes in near-field, wellbore, and reservoir conditions that are apparent approximately two years following the end of injection. This comparative hydrologic test analysis method provides a new way to quantify the amount of injected CO 2 that was mineralized in the field test. Modeling results indicate that approximately 60% of the injected CO 2 was sequestered via mineralization within two years, with the resulting carbonates occupying ~4% of the available reservoir pore space. The method presented here provides a new monitoring tool to assess the fate of CO 2 injected into chemically reactive basalt formations but could also be adapted for long-term monitoring and verification within more traditional subsurface carbon storage reservoirs.
54 ENVIRONMENTAL SCIENCES↗
Water Availability for Biorefineries in the Contiguous United States and the Implications for Bioenergy Production Distribution
Renewable biofuel production depends on many factors, including feedstock availability, refinery and shipment infrastructure, and in particular, water availability. This study assesses water requirement and availability for mainstream biorefinery technologies in the contiguous United States (CONUS). The assessment is conducted in newly defined spatial units, namely, biorefinery planning boundaries, considering feedstock availability, transportation cost, and refinery capacity requirement for cost-effectiveness. The results suggest that the total biorefinery water use in the CONUS by 2030 will be low compared to the total water availability. However, biorefinery water requirements can aggravate the water stress situation in many regions, including the Great Plains, California Central Valley, and the upper Columbia-Snake River basin in Washington. Bioenergy productions in these regions can be largely constrained by water. Here, it is projected that biofuel production will concentrate in Northern Plains, Lake States, and Corn Belt regions, which contribute 94.4% of the conventional, 86.1% of biodiesel, and 54.8% of cellulosic biofuel production mandated by the renewable fuel standard. If biorefineries are constrained to use less than 10% of the locally available water, up to 7% of planned cellulosic biofuel production will be affected. Findings from this study can aid the sustainable planning of national bioenergy production.
54 ENVIRONMENTAL SCIENCES↗
Tc(VII) and Cr(VI) Interaction with Naturally Reduced Ferruginous Smectite from a Redox Transition Zone
Fe(II)-rich clay minerals found in subsurface redox transition zones (RTZs) can serve as important source of electron equivalents limiting the transport of redox active contaminants. While most laboratory reactivity studies are based on reduced model clays, the reactivity of naturally reduced clays in field samples remains poorly explored. Characterization of the clay size fraction of a fine-grained unit from RTZ interface at the Hanford site, Washington, including mineralogy, crystal chemistry, and Fe(II)/(III) content, indicates that ferruginous montmorillonite is the dominant mineralogical component. Oxic and anoxic fractions differ significantly in Fe(II) concentration, but FeTOTAL remains constant demonstrating no Fe loss during reduction-oxidation cycling. At its native pH of 8.6, the anoxic fraction despite its significant Fe(II) (~23% of FeTOTAL), exhibits minimal reactivity with TcO4- and CrO42- and much slower reaction kinetics than that measured in studies with biologically/chemically reduced model clays. Reduction capacity is enhanced by added Fe(II) (if Fe(II)SORBED >8% clay Fe(II)LABILE), however the kinetics of this conceptually surface-mediated reaction remain sluggish. Surface-sensitive Fe L-edge X-ray absorption spectroscopy shows that Fe(II)SORBED and the resulting reducing equivalents are not available in the outermost few nanometers of clay surfaces. Slow kinetics thus appear related to diffusion-limited access to electron equivalents retained within clay mineral.
Environmental Molecular Sciences Laboratory↗
Field Validation of Supercritical CO 2 Reactivity with Basalts
Continued global use of fossil fuels places a premium on developing technology solutions to minimize increases in atmospheric CO 2 levels. CO 2 storage in reactive basalts might be one of these solutions by permanently converting injected gaseous CO 2 into solid carbonates. Herein we report results from a field demonstration where ~1000 MT of CO 2 was injected into a natural basalt formation in Eastern Washington State. Following two years of post-injection monitoring, cores were obtained from within the injection zone and subjected to detailed physical and chemical analysis. Nodules found in vesicles throughout the cores were identified as the carbonate mineral, ankerite Ca[Fe, Mg, Mn](CO 3 ) 2 . Carbon isotope analysis showed the nodules are chemically distinct as compared with natural carbonates present in the basalt and clear correlation with the isotopic signature of the injected CO 2 . These findings provide field validation of rapid mineralization rates observed from years of laboratory testing with basalts.
54 ENVIRONMENTAL SCIENCES↗
CO 2 Mineral Sequestration in Naturally Porous Basalt
Continental flood basalts are extensive geologic features currently being evaluated as reservoirs that are suitable for long-term storage of carbon emissions. Favorable attributes of these formations for containment of injected carbon dioxide (CO2) include high mineral trapping capacity, unique structural features, and enormous volumes. We experimentally investigated mineral carbonation in whole core samples retrieved from the Grand Ronde basalt, the same formation into which ~1000 t of CO2 was recently injected in an eastern Washington pilot-scale demonstration. The rate and extent of carbonate mineral formation at 100 °C and 100 bar were tracked via time-resolved sampling of bench-scale experiments. Basalt cores were recovered from the reactor after 6, 20, and 40 weeks, and three-dimensional X-ray tomographic imaging of these cores detected carbonate mineral formation in the fracture network within 20 weeks. Under these conditions, a carbon mineral trapping rate of 1.24 ± 0.52 kg of CO2/m3 of basalt per year was estimated, which is orders of magnitude faster than rates for deep sandstone reservoirs. On the basis of these calculations and under certain assumptions, available pore space within the Grand Ronde basalt formation would completely carbonate in ~40 years, resulting in solid mineral trapping of ~47 kg of CO2/m3 of basalt.
Xiong, Wei↗
First-Principles Thermodynamics Study of Spinel MgAl 2 O 4 Surface Stability
The surface stability of all possible terminations for three low-index (111, 110, 100) structures of the spinel MgAl2O4 has been studied using first-principles based thermodynamic approach. The surface Gibbs free energy results indicate that the 100_AlO2 termination is the most stable surface structure under ultra-high vacuum at T=1100 K regardless of Al-poor or Al-rich environment. With increasing oxygen pressure, the 111_O2(Al) termination becomes the most stable surface in the Al-rich environment. The oxygen vacancy formation is thermodynamically favorable over the 100_AlO2, 111_O2(Al) and the (111) structure with Mg/O connected terminations. On the basis of surface Gibbs free energies for both perfect and defective surface terminations, the 100_AlO2 and 111_O2(Al) are the most dominant surfaces in Al-rich environment under atmospheric condition. This is also consistent with our previously reported experimental observation. This work was supported by a Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL). The computing time was granted by the National Energy Research Scientific Computing Center (NERSC). Part of computing time was also granted by a scientific theme user proposal in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington.
ab initio calculation↗
Mechanisms of Semiconducting 2H to Metallic 1T Phase Transition in Two-dimensional MoS 2 Nanosheets
In the present work, phase transition mechanisms from semiconducting 2H phase to metallic 1T phase in MoS 2 nanosheets were studied using density functional theory (DFT) method. Various 2H→1T phase transition mechanisms that consist of nucleation and propagation steps, which simulated by collective rotational and rotational/translational movements, single atom translational movement, as well as the gliding movement of one row for sulfur (S) atoms, on both the basal plane and Mo- and S-edges with different S coverages were investigated. On the perfect basal plane, the 1T phase nucleation is unlikely due to the extremely high barrier of 2.25 eV/atom. Whereas the presence of defective S vacancies on the basal plane dramatically facilitate the 1T phase nucleation and propagation around the defective sites by the collective rotational movement of three S atoms. On the 2H phase basal plane with two S vacancies, the kinetic barriers for the 1T phase nucleation are as low as of 0.66~0.77 eV/atom. Like the promoting effect of S vacancies on the phase transition over the basal plane, DFT results suggest that the S coverage on the Mo- and S-edges will affect the 1T phase nucleation and propagation. The 1T phase nucleation starting with the translational movement of single S atom on the bare Mo-edge and the gliding movement of an entire row of S atoms on the S-edge with 50%S coverage are kinetically favorable. While the 1T phase formation at the Mo-edge with 50%S coverage and the S-edge with 100% S coverage are unlikely. The present work not only confirms the important role of S vacancies/coverages in the 2H-1T phase transition, but also provides new insight into how and where the 2H-1T phase transition occurs at the atomic level, which also sheds light on the general phase transition mechanism for two-dimensional transition metal dichalcogenide materials. The work was financially supported by the National Natural Science Foundation of China (No. 21476012, 21571012, and 91534201). Q. Jin appreciates the joint Ph.D. scholarship support from the China Scholarship Council. The computing time was granted by a scientific theme user proposal in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington. D. Mei is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.
Molybdenum disulfide, phase transition, sulfur vac↗
Determination of the Dominant Catalyst Derived from the Classic [RhCp*Cl[subscript 2]][subscript 2] Precatalyst System: Is it Single-Metal Rh[subscript 1]Cp*-Based, Subnanometer Rh4 Cluster-Based, or Rh(0)[subscript n] Nanoparticle-Based Cyclohexene Hydrogenation Catalysis at Room Temperature and Mild Pressures?
Abstract not provided
Bayram, Ercan↗
Impact of pH on Aqueous-Phase Phenol Hydrogenation Catalyzed by Carbon-Supported Pt and Rh
In aqueous phase, the rates of hydrogenation of aromatic substrates such as phenol on Pt/C and Rh/C are influenced by varying activity of hydronium ions. Decreasing the pH from 8 to 1 increases the rate of hydrogenation of phenol on Pt at 20 bar H 2 and 80 °C by 15-fold. This increase is attributed to weakening of the hydrogen binding energy (HBE) on the metal surface with decreasing pH. A weaker HBE at lower pH is also predicted by ab initio molecular dynamics simulations, providing atomistic insight into the impact of electrolyte ion distribution and interfacial solvent reorganization on HBE. The lower HBE results in a decrease in the activation energy for addition of adsorbed H from the metal to the adsorbed organic (with a Brønsted–Evans–Polanyi slope of ~1). In conclusion, the kinetic model derived accounts also for the lack of pH dependence at low hydrogen coverages (at 1 bar H 2 on Pt or up to 70 bar H 2 on Rh), when the weakening of the HBE decreases the hydrogen coverage.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗