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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Recent advances in hybrid metal oxide–zeolite catalysts for low-temperature selective catalytic reduction of NOx by ammonia

A hybrid catalytic system comprised of metal oxide and Cu or Fe exchanged zeolite components represents a potential advancement of state-of-the-art for selective catalytic reduction (SCR) of NOx by ammonia, including an elegant solution to the current challenge of improving the low-temperature efficiency of SCR catalysts. The idea is to enable in-situ NO oxidation over metal oxide component and concomitant fast SCR over zeolite component in the so-called “bifunctional mechanism”. This review is presented in the wake of growing interest in this innovative catalytic system. We begin this review by presenting key parameters that contribute to the synergy between metal oxide and zeolite components. Then, we discuss the materials selection for both components and their possible interactions in the system, followed by a summary of recent NH3-SCR investigations over multiple metal oxide–zeolite pairs and additional discussion on pairing techniques potentially explorable in upcoming studies. Finally, we end the review by providing the perspectives on future challenges in the development of this catalytic system.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

The rhizosphere and cropping system, but not arbuscular mycorrhizae, affect ammonia oxidizing archaea and bacteria abundances in two agricultural soils

Arbuscular mycorrhizal fungi (AMF) form symbioses with roots that can enhance plant nutrition. While AMF have been shown to have a role in soil nitrogen (N) cycling, it is unclear whether AMF affect N cycling microbes such as ammonia-oxidizing bacteria (AOB) and archaea (AOA), which convert ammonium into nitrite in the first step of nitrification. In this study, we examined the effects of AMF on AOA and AOB abundances within the corn rhizosphere and bulk soil of conventional (corn-soybean rotation with inorganic fertilizer) and diversified (cornsoybean- oats/alfalfa-oats rotation with composted manure) systems. We hypothesized that AMF would decrease AOA and AOB abundances in a cropping-system dependent manner, possibly due to competition for ammonium. We grew corn deficient or proficient in AMF symbiosis in microcosms for 10 weeks. At the end of the experiment, both soils planted with the AMF-proficient corn genotype had higher ammonium and lower nitrate pool sizes compared to the same soils planted with the AMF-deficient corn genotype. Likewise, total plant N was higher in the AMF-proficient genotype compared to the AMF-deficient genotype. Despite changes in soil inorganic N pool sizes, AOA and AOB abundances were unaffected by plant AMF-proficiency. Instead, AOA abundance was greater in the rhizosphere than in the bulk soil regardless of cropping system, and AOB abundance was greater in the conventional than the diversified cropping system soil regardless of proximity to the root. These data indicate that 1) AMF did not affect AOA or AOB abundance in these N-rich soils but other factors such as root proximity and inorganic fertilization did and 2) AOA and AOB have differing ecological niches within rhizosphere and bulk soil that should be considered when managing for nitrogen losses.

Wattenburger, Cassandra↗
DOE OSTI2026

Ammonia in northeast Colorado is increasing, rising most quickly in regions close to confined animal feeding operations

The Colorado Front Range urban corridor and nearby agricultural operations are important source regions of atmospheric ammonia (NH 3 ). Upslope flows periodically transport these emissions into Rocky Mountain National Park (RMNP), located 50 km west of the urban corridor, where wet and dry deposition of excess reactive nitrogen (N) impacts ecosystems. Here, we use a combination of in situ passive NH 3 measurements and NH 3 vertical column density retrievals from the Infrared Atmospheric Sounding Interferometer (IASI) to assess variability and changes in NH 3 across three land use categories in the northeast Colorado source region (agricultural, urban, and remote) during the period 2013-2023. A strong seasonal cycle is present across the region with increased NH 3 during summer months. Elevated NH 3 is spatially correlated with the number of permitted animal units in confined animal feeding operations (CAFOs) within 12 km. Ground-level NH 3 concentrations are strongly positively correlated with monthly gridded IASI satellite column densities. Satellite retrievals reveal an increasing trend in NH 3 column amounts of ∼3% per year in agricultural and ∼2% per year in urban sub-regions. The magnitude of the trend observed in NH 3 columns averaged over the agricultural sub-region is > 3 times larger than observed near and over Denver. The largest increases in NH 3 are closely aligned with the distribution of CAFOs. Reductions in particle sulfate associated with declining sulfur dioxide (SO 2 ) emissions could account for only ∼0.1% per year increase in gaseous NH 3 . Wildfire smoke across the region has increased but appears unlikely to explain the majority of the observed NH 3 increase.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Effect of pelleting process variables on physical properties and sugar yields of ammonia fiber expansion pretreated corn stover

Pelletization process variables including grind size (4, 6 mm), die speed (40, 50, 60 Hz), and preheating (none, 70 degrees C) were evaluated to understand their effect on pellet quality attributes and sugar yields of ammonia fiber expansion (AFEX) pretreated biomass. The bulk density of the pelletized AFEX corn stover was three to six times greater compared to untreated and AFEX-treated corn stover. Also the durability of the pelletized AFEX corn stover was >97.5% for all pelletization conditions studied except for preheated pellets. Die speed had no effect on enzymatic hydrolysis sugar yields of pellets. Pellets produced with preheating or a larger grind size (6 mm) had similar or lower sugar yields. Pellets generated with 4 mm AFEX-treated corn stover, a 60 Hz die speed, and no preheating resulted in pellets with similar or greater density, durability, and sugar yields compared to other pelletization conditions.

09 BIOMASS FUELS↗
DOE OSTI2018

Incorporating anaerobic co-digestion of steam exploded or ammonia fiber expansion pretreated sugarcane residues with manure into a sugarcane-based bioenergy-livestock nexus

The co-digestion of pretreated sugarcane lignocelluloses with dairy cow manure (DCM) as a bioenergy production and waste management strategy, for intensive livestock farms located in sugarcane regions, was investigated. Ammonia fiber expansion (AFEX) increased the nitrogen content and accelerated the biodegradability of sugarcane bagasse (SCB) and cane leaf matter (CLM) through the cleavage of lignin carbohydrate crosslinks, resulting in the highest specific methane yields (292–299 L CH4/kg VSadded), biogas methane content (57–59% v/v) and biodegradation rates, with or without co-digestion with DCM. To obtain comparable methane yields, untreated and steam exploded (StEx) SCB and CLM had to be co-digested with DCM, at mass ratios providing initial C/N ratios in the range of 18 to 35. Co-digestion with DCM improved the nutrient content of the solid digestates, providing digestates that could be used as biofertilizer to replace CLM that is removed from sugarcane fields during green harvesting.

09 BIOMASS FUELS↗
DOE OSTI2014

Ammonia reactions with the stored oxygen in a commercial lean NO x trap catalyst

Ammonia is an important intermediate of the NO x reduction in a NO x storage and reduction catalyst (aka lean NO x trap). NH 3 formed under rich conditions in the reduced front part of the catalyst is transported by convection downstream to the unregenerated (still oxidized) zone of the catalyst, where it further reacts with the stored oxygen and NO x . In this paper, the kinetics and selectivity of NH 3 reactions with the stored oxygen are studied in detail with a commercial Ba-based NO x storage catalyst containing platinum group metals (PGM), Ba and Ce oxides. Furthermore, steady-state NH 3 decomposition, NH 3 oxidation by O 2 and NO, and N 2 O decomposition are examined in light-off experiments. Periodic lean/rich cycling is measured first with O 2 and NH 3 , and then with NO x + O 2 and NH 3 to discriminate between the NH 3 reactions with the stored oxygen and the stored NO x . The reaction of NH 3 with the stored O 2 is highly selective towards N 2 , however a certain amount of NO x and N 2 O is also formed. The formed NO x by-product is efficiently adsorbed on the NO x storage sites such that the NO x is not detected at the reactor outlet except at high temperatures. The stored NO x reacts with NH 3 feed in the next rich phase, contributing to the N 2 O formation. Water inhibits the reactions of NH 3 with the stored oxygen. On the contrary, the presence of CO 2 increases the NH 3 consumption. Furthermore, CO 2 is able to provide additional oxygen for NH 3 oxidation, forming –CO in analogy to the reverse water gas shift reaction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Na + -gated nanochannel membrane for highly selective ammonia (NH 3 ) separation in the Haber-Bosch process

Currently, cryogenic condensation is the predominant process for recovering ammonia (NH 3 ) in the Haber-Bosch (HB) process, which is highly energy intensive. To be more compatible with the reaction conditions in the HB process and thus minimize the pressure and temperature swing during reactant recycling, energy-efficient technologies for NH 3 extraction at elevated temperature and pressure are greatly needed. In this work, the Na + -gated nanochannel membrane, shown exclusively for water conduction in our previous work, also exhibited highly NH 3 -selective performance, with NH 3 /H 2 selectivity as high as 4,280 and NH 3 /N 2 selectivity > 10,000 at temperature up to 250 °C and pressure up to 35 bar. Excellent stability of the Na + -gated nanochannel membrane was demonstrated during a 100-h run in ternary NH 3 /H 2 /N 2 gas mixture at 200 °C and 35 bar, consistent with structural characterization by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transfer infrared (FTIR) spectroscopy. A techno-economic analysis (TEA) was conducted for the HB process using the Na + -gated nanochannel membrane and the traditional HB process with condenser. Finally, under the optimized separation conditions, > 80% energy savings and approximately 20% reduction of the net NH 3 production cost can be achieved, demonstrating the great potential of the Na + -gated nanochannel membrane for NH 3 separation in the HB process.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Impacts of anthropogenic gadolinium on the activity of the ammonia oxidizing bacterium Nitrosomonas europaea

Widespread use of gadolinium-based contrast agents in medical imaging has resulted in increased Gd inputs to municipal wastewater treatment plants. Others have reported that typical wastewater treatment does not attenuate Gd, resulting in discharges to natural waters. However, whether elevated Gd impacts the performance of biological treatment has not been investigated. We examined whether gadolinium chloride or Gd chelated with diethylenetriaminepentaacetic acid (DTPA) affected the activity of the model nitrifying bacterium Nitrosomonas europaea. At nominal GdCl 3 additions ranging from 1 to 500 µM, no impact was observed compared to the control. Most (>98%) of the added Gd precipitated, and extracellular GdPO 4 nanoparticles were observed. When chelated with DTPA, Gd remained soluble, but no statistically significant impact on ammonia oxidation was observed until the highest concentrations tested. At 300 and 500 µM Gd-DTPA, a temporary reduction of nitrite production relative to the control (effect size 1.3 mg l -1 and 1.5 mg l -1 , respectively, at 24 h) was seen. By itself, DTPA was highly inhibitory. Modeling suggested that DTPA likely chelated other metals, but adjusting the concentrations of the most abundant metals in the medium, calcium and magnesium, indicated that lowering their free ion activities was probably not the cause of inhibition. Complexation of other essential metals was more likely. Furthermore, our studies indicate that while the low bioavailability of Gd may limit its ecosystem impacts, the role of synthetic ligands used with Gd and other rare earth elements should e considered as the production, use and disposal of these elements increases.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Decomposition of ammonia on ZrB 2 (0001)

Zirconium diboride has been recently identified as a promising substrate for the growth of Group-III nitride semiconductors using reactive vapors that include ammonia as the nitrogen source. Adsorption energies and dissociation pathways of NH 3 on the (0001) surface of ZrB 2 were investigated using density functional theory calculations. Here, our results indicate that NH 3 readily adsorbs onto the ZrB 2 surface terminated with Zr and decomposes to atomic N and H with relatively small activation barriers. The resulting atomic species are found to be mobile with the computed diffusion barriers between 0.11 and 0.78 eV.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Rotational dynamics in ammonia borane: Evidence of strong isotope effects

This work reports anelastic spectroscopy measurements on the partially deuterated (ND3BH3 and NH3BD3) and perdeuterated (ND3BD3) ammonia borane (NH3BH3) compounds. The relaxations previously reported in NH3BH3 are observed in all the samples, and are ascribed to the rotational and torsional dynamics of NH(D)3BH(D)3 complexes. A new thermally activated peak appears at 70 K (for a vibration frequency of 1 kHz) in the spectrum of NH3BD3 and ND3BD3. The peak is practically a single-time Debye process, indicating absence of interaction between the relaxing units, and has a strikingly high intensity. A secondary relaxation process is also detected around 55 K. The anelastic spectrum of the ND3BH3 only displays this less intense process at 55 K. The analysis of the peaks supplies information about the dynamics of the relaxing species, and the obtained results provide indications on the effect of partial and selective deuteration on the hydrogen (deuterium) dynamics.

hydrogen absorbing materials↗
DOE OSTI2021

Green hydrogen from microalgal liquefaction byproducts with ammonia recovery and effluent recycle for developing circular processes

Hydrothermal liquefaction is a promising technology for microalgae-based biofuel production. However, hydrothermal liquefaction’s aqueous wastes have little established reuse, and contain significant fractions of toxic ammoniacal nitrogen. Careful reuse of this waste can assure microalgae-based biofuels are produced with less environmental impact and larger energy efficiency. Microbial electrolysis cells were investigated to valorize this waste product by converting the leftover organics into hydrogen and remove ammonia. Waste hydrothermal liquefaction aqueous phase from two microalgal strains, Tetraselmis sp. and Chlorella sp. were used as feedstocks for hydrogen production in microbial electrolysis cells. Chlorella and Tetraselmis aqueous phase-fed microbial electrolysis cells reach an average current density of 5.1 ± 0.19 A/m 2 and 3.8 ± 0.08 A/m 2 . Compound removal rates and mass removal percentages were also investigated for each feedstock. Additionally, acetic acid, propionic acid, ethanol, and glycerol were effectively removed from the aqueous byproduct. Further, microbial electrolysis cells separated up to 34.3% of ammoniacal nitrogen present in the aqueous phase. Charge transfer analysis indicated that proton transfer, not ammonium transfer, contributed to the majority of the hydrogen production in the cathode. Finally, the microbial electrolysis cell effluent was reused to grow the same microalgal strains, leading to the development of a circular biofuel production system. Microalgae regrowth studies using microbial electrolysis cell effluent showed nearly complete removal of total organic carbon, but significantly less removal of total nitrogen. Tetraselmis sp. growth occurred with the Tetraselmis-derived MEC effluent, however, the control medium without effluent produced the most growth. These findings support the possibility of a circular biofuel framework using MECs, but additional constraints, including the removal of inorganic contaminants, are necessary to realize the circular processes.

09 BIOMASS FUELS↗
DOE OSTI2015

GaN nanowires with pentagon shape cross-section by ammonia-source molecular beam epitaxy

In this study, ammonia-based molecular beam epitaxy (NH 3 -MBE) was used to grow catalyst-assisted GaN nanowires on (11¯02) r-plane sapphire substrates. Dislocation free [112¯0] oriented nanowires are formed with pentagon shape cross-section, instead of the usual triangular shape facet configuration. Specifically, the cross-section is the result of the additional two nonpolar {101¯0} side facets, which appear due to a decrease in relative growth rate of the {101¯0} facets to the {101¯1} and {101¯1} facets under the growth regime in NH 3 -MBE. Compared to GaN nanowires grown by Ni-catalyzed metal–organic chemical vapor deposition, the NH 3 -MBE grown GaN nanowires show more than an order of magnitude increase in band-edge to yellow luminescence intensity ratio, as measured by cathodoluminescence, indicating improved microstructural and optical properties.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2025

200 h of discharge cycling with an all-aqueous copper thermally regenerative ammonia battery

Thermally regenerative ammonia batteries (TRABs) offer an approach to energy storage and electricity generation by harnessing low-grade heat (T < 150 °C). A TRAB discharge resembles that of a flow battery, where electrochemical reactions produce electrical power from energy stored within aqueous electrolytes. While there are many types of TRABs, the all-aqueous copper TRAB (Cu aq -TRAB) has produced the largest power and energy storage densities. Despite many improvements to TRAB performance, most tests have only lasted a few hours, which are not representative of operation times expected of these devices. Herein, we operated a Cu aq -TRAB for 200 h of constant current discharging to assess battery performance and component stability. After 200 h of testing, the average power density increased slightly to 7.2 mW cm -2 , which was within 0.01 % of starting conditions. Likewise, the average energy density for the final cycle was only 0.03 % lower than the initial cycle. The overall insensitivity of the power cell to cycling represents a major milestone in the advancement of TRAB systems. In conclusion, energy dispersive X-ray spectroscopy provides evidence to suggest that these small changes in power and energy density are likely to the membrane acclimating to TRAB electrolytes.

25 ENERGY STORAGE↗
DOE OSTI2019

The double spin asymmetry of nitrogen in elastic and quasielastic kinematics from a solid ammonia dynamically polarized target

Solid ammonia is commonly used as a dynamically polarized proton target for electron and muon scattering cross-section asymmetry measurements. As spin 1$^{+}$ particles, the $^{14}$N nuclei in the target are also polarized and contribute a non-trivial asymmetry background that should be addressed. HereWe describe here a method to extract the nitrogen contribution to the asymmetry, and report the cross-section asymmetries of electron-nitrogen scattering at beam energies of $E=1.7$ GeV and $E=2.2$ GeV, and momentum transfer of $Q^{2}=0.023-0.080$ GeV$^{2}$.

47 OTHER INSTRUMENTATION↗
DOE OSTI2017

CuNi Nanoparticles Assembled on Graphene for Catalytic Methanolysis of Ammonia Borane and Hydrogenation of Nitro/Nitrile Compounds

Here we report a solution phase synthesis of 16 nm CuNi nanoparticles (NPs) with the Cu/Ni composition control. These NPs are assembled on graphene (G) and show Cu/Ni composition-dependent catalysis for methanolysis of ammonia borane (AB) and hydrogenation of aromatic nitro (nitrile) compounds to primary amines in methanol at room temperature. Among five different CuNi NPs studied, the G-Cu 36 Ni 64 NPs are the best catalyst for both AB methanolysis (TOF = 49.1 mol H2 mol CuNi -1 min -1 and E a = 24.4 kJ/mol) and hydrogenation reactions (conversion yield >97%). In conclusion, the G-CuNi represents a unique noble-metal-free catalyst for hydrogenation reactions in a green environment without using pure hydrogen.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2022

First-Principles Insights into the Thermocatalytic Cracking of Ammonia-Hydrogen Blends on Fe(110): 1. Thermodynamics

Ammonia (NH 3 ) is being considered as a practical means to transport hydrogen (H 2 ) because of its higher volumetric energy density for the same temperature and pressure. Thermodynamics suggest high temperature is needed to decompose NH 3 to nitrogen (N 2 ) and H 2 . Furthermore, overcoming decomposition kinetic barriers requires a catalyst. Via density functional theory, we study this reaction on a model catalyst: the close-packed (110) facet of α-Fe. Specifically, we predict detailed in-operando temperature- and pressure-dependent surface phase diagrams on this benchmark catalyst that offer insights for the design of optimal NH 3 decomposition catalysts. Here, we explore the equilibrium composition(s) of the Fe(110) surface when exposed to NH 3 –H 2 mixtures. Further, we predict that both N and NH partially cover the Fe(110) surface at 300–400 °C (far above the NH 3 decomposition-formation coexistence temperature at standard partial pressures of 1 bar: ~ 180 °C) and 2–4 bar of total reactor pressure. At the equilibrium N/NH coverage, these species inhibit coadsorption of H, indicating that direct H 2 production may occur. However, from thermodynamics alone, removal of N/NH as N 2 (g) is extremely unfavorable even at these elevated temperatures–effectively deactivating the surface toward further NH 3 decomposition. Thus, catalysts that remain active toward N–H bond breaking but with weakened N binding relative to Fe are needed to enable high-turnover catalytic NH 3 decomposition to release H 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

First-Principles Insights into the Thermocatalytic Cracking of Ammonia-Hydrogen Blends on Fe(110). 2. Kinetics

Ammonia (NH 3 ) is an energy-rich molecule that is routinely synthesized from nitrogen (N 2 ) and hydrogen (H 2 ). NH 3 ’s more favorable physical properties compared to H 2 suggests it may offer a way to more conveniently store, transport, and, when needed, extract H 2 via thermal decomposition. However, the high kinetic barrier and endoergicity to decompose to H 2 and N 2 require high temperatures. The standard reaction free energy indicates nearly 100% thermodynamic conversion to the diatomic molecules only at ~673 K and higher. However, even at these temperatures, a catalyst, e.g., iron (Fe), is needed for favorable kinetic conversion. Here, in this study, we explore via density functional theory the kinetics of NH 3 decomposition on the most stable facet of body-centered cubic Fe, namely, (110), under typical high-temperature and finite-pressure operando conditions. We predict coverage-dependent energetics of elementary surface reactions, often neglected in atomic-scale modeling. From these models, we find the recombinative desorption of adsorbed N as N 2 is rate-determining at 573.15–773.15 K and even at an extreme case of 1173.15 K. From microkinetic modeling, we find that the steady-state turnover frequencies (TOFs) for N 2 and H 2 generation rates (r$_{H_2}$) depend exponentially on temperature. The catalyst achieves a steady-state TOF of 36.4 s –1 and an r$_{H_2}$ of 0.107 μmol cm –2 s –1 for a feed of 1.8 bar NH 3 with 0.2 bar H 2 at 1173.15 K. However, at 773.15 K, with the same feed composition and velocity, the steady-state TOF and r$_{H_2}$ decrease to 0.14 s –1 and 4.10 × 10 –4 μmol cm –2 s –1 , respectively, as the process is significantly hindered by slow N 2 desorption. Although at first glance counterintuitive, our simulations suggest that surface modifications that reduce Fe’s reactivity toward NH x species should enhance its overall NH 3 decomposition activity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Machine-Learned Force Field for Molecular Dynamics Simulations of Nonequilibrium Ammonia Synthesis on Iron Catalysts

Ammonia (NH 3 ) is one of the most important industrial chemicals. The conventional NH 3 synthesis method-the Haber–Bosch process-converts atmospheric nitrogen (N 2 ) into NH 3 using H 2 with an iron (Fe) catalyst. However, this process requires high pressures (100–200 atm) and temperatures (700–800 K) near thermal equilibrium. Recently, Fe-based nanocatalysts have been reported to produce promising NH 3 yields under atmospheric pressures and temperature-modulated nonequilibrium conditions. Understanding the mechanism of nonequilibrium catalysis with programmed temperature variation could help to optimize this fully electrified and less energy-intensive process. Although reactive molecular dynamics (RMD) simulations can be a useful tool to model nonequilibrium catalytic processes, they require the development of accurate force fields (i.e., interatomic potentials). Here, we present a machine-learned (ML) force field within the Deep Potential MD (DPMD) framework, trained using periodic density functional theory (DFT) calculations, to model NH 3 synthesis on Fe catalysts with various surface adsorbates such as *N, *H, *N 2 , *H 2 , *NH, *NH 2 , and *NH 3 . Here, we generated the DFT data from static models of elementary reactions on the most stable (110) surface of body-centered cubic Fe, which then were augmented by data from constant number of particles–volume–temperature (NVT) DFT-MD trajectories at various temperatures. Finally, we utilized the fully optimized ML force field to investigate reaction dynamics at an Fe(110) surface at linearly increasing temperatures using NVT-DPMD simulations. Our simulations indicate that pulsed temperature ramping could prove favorable for NH3 synthesis. For example, we conducted ramping under multiple sets of conditions: (i) from 900 to 1200 K over periods of 0.1–0.3 ns for Fe surfaces precovered with N or NH along with H; and (ii) from 300 to 600 K over 0.1–0.3 ns for Fe surfaces precovered with NH 3 . While our simulations so far are limited to short time scales (very rapid heating), these observations shed light on the mechanism of the high NH 3 synthesis rate achieved in a novel temperature-modulated nonequilibrium catalytic reactor using pulsed heating and cooling.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗