On-line Gas Analysis Research Articles

A Comprehensive Online Analytical System Coupled with Standardized Data Analysis for the Electrochemical Reduction of CO2

The electrochemical reduction of CO2 (CO2RR) is a promising way to convert detrimental CO2 emissions into sustainable fuels and chemicals, and thus to achieve a circular carbon economy. 1 Depending on catalyst type and reaction conditions, different gaseous and liquid products can be obtained from the CO2RR, and their production rates vary with reaction time. It becomes thus imperative, for any catalytic performance analysis, to be able to assess the product distribution online during CO2RR. 2,3 However, while gaseous products are readily analyzed online by gas chromatography, liquid products are typically only assessed at the end of the reaction due to the lack of suitable automated liquid sampling and analysis methods. In addition, reaction parameters such as CO2 mass flow rates, temperatures and pressures are seldom recorded, causing the loss of significant information on catalysts, electrodes, and electrolyzers behavior.To overcome these issues, we assemble a comprehensive analytical system coupling online gas and liquid product analysis by gas and liquid chromatography leveraging a special automated liquid sampling valve with electrochemical protocols that assess CO2RR performance, electrolyzer cell resistance and electrode surface area. In addition, we record CO2 mass flow rates, electrolyzer temperatures, as well as gas and liquid flow pressures. 4 To rapidly and reproducibly handle the large and heterogeneous data volume obtained we implement a standardized data pipeline based on our own open-source software,5 which automatically parses the numerous different raw data files, composes a data set following FAIR practices,6 and post-processes and plots the data in a standardized way. We validate the analytical system by carrying out CO2RR at 200 mA/cm2 on Cu gas diffusion electrodes, following the changes in selectivity with reaction time for > 10 gaseous and liquid products, and recording mass flow rates, electrolyzer temperatures and pressures. The modular nature of our analytical system, combined with the standardized data pipeline, allows us to freely increase the number and type of sensors used with minimal impact on the data analysis time, as well as to multiplex our analysis to 8 parallel electrolyzer cells, paving the way for a much deeper and faster understanding of the function of CO2RR catalysts, electrodes, and electrolyzers.

Wavelength-modulated photoacoustic spectroscopic instrumentation system for multiple greenhouse gas detection and in-field application in the Qinling mountainous region of China

We present a sensitive and compact quantum cascade laser-based photoacoustic greenhouse gas sensor for the detection of CO2, CH4 and CO and discuss its applicability toward on-line real-time trace greenhouse gas analysis. Differential photoacoustic resonators with different dimensions were used and optimized to balance sensitivity with signal saturation. The effects of ambient parameters, gas flow rate, pressure and humidity on the photoacoustic signal and the spectral cross-interference were investigated. Thanks to the combined operation of in-house designed laser control and lock-in amplifier, the gas detection sensitivities achieved were 5.6 ppb for CH4, 0.8 ppb for CO and 17.2 ppb for CO2, signal averaging time 1 s and an excellent dynamic range beyond 6 orders of magnitude. A continuous outdoor five-day test was performed in an observation station in China’s Qinling National Botanical Garden (E longitude 108°29’, N latitude 33°43’) which demonstrated the stability and reliability of the greenhouse gas sensor.

Silane Gas Production Through Hydrolysis of Magnesium Silicide by Hydrochloric Acid

Monosilane (SiH4) is a common precursor for the production of high-purity silicon for solar PV applications. As an alternative to carbothermic reduction of silica to produce metallurgical grade silicon with subsequent conversion to silane, an alternative route over magnesiothermic reduction of silica to Mg2Si has been explored in our earlier work. In the current work, silane gas production through hydrolysis of Mg2Si in HCl acid solution was studied. Two sources of Mg2Si were chosen: a commercial Mg2Si source and a Mg2Si source produced through magnesiothermic reduction of high-purity natural quartz. Effects of various parameters on the hydrolysis of Mg2Si, including different experimental setups, temperature of the acid solution, acid concentration, reaction time, and relative amounts of reactants were studied. The evolution of produced gases was determined by two different methods: firstly, by passing the produced gas through a KOH solution to capture Si with subsequent analysis of the Si content in the KOH solution by inductively coupled plasma mass spectrometry and secondly, on-line gas analysis by GC–MS. The silane distribution between different silane species with reaction time was evaluated and the activation energy of silane formation was calculated. The results indicated comparable silane yields obtained from the on-line GC–MS method and KOH solution analysis method, as well as for commercial Mg2Si and the Mg2Si–MgO mixture produced through magnesiothermic reduction. Furthermore, adding HCl acid to Mg2Si in water led to higher SiH4 formation yield than adding Mg2Si to acid. However, the total silane yield for the two methods was similar at approximately 32%.Graphical

Advanced Analytical System with Standardized Data Analysis for Electrochemical CO2 Reduction

Electrochemical CO2 reduction (CO2RR) is a promising way to convert CO2 emissions into sustainable fuels and chemicals, approaching a circular carbon economy. 1 Depending on catalyst type and reaction conditions, different gaseous and liquid products can be obtained from the CO2RR, and their production rates vary with reaction time. Thus, assessing the product distribution online during CO2RR is a key component of any catalytic performance analysis. 2,3 However, while gaseous products are readily analyzed online, liquid products are assessed typically only at the end of the reaction due to the lack of suitable automated liquid sampling and analysis methods. In addition, electrolyzer parameters such as gas flow rates, temperatures and pressures are seldom recorded, causing the loss of significant information on catalysts, electrodes, and electrolyzers behavior.To overcome these issues, we assemble a comprehensive analytical system coupling online gas and liquid product analysis by chromatography (leveraging a special automated liquid sampling valve) with electrochemical protocols to assess CO2RR performance, electrolyzer cell resistance and electrode surface area. In addition, we record CO2 gas flow rates, electrolyzer temperatures, and gas and liquid pressures. 4 To rapidly and reproducibly handle the large and heterogeneous data volume obtained we implement a standardized data pipeline based on our own open-source software,5 which automatically parses the numerous different raw data files, composes a data set following FAIR practices,6 and post-processes and plots the data in a standardized way (see example in Fig. 1 below). We validate the analytical system by carrying out CO2RR at 200 mA/cm2 on Cu gas diffusion electrodes, following the changes in selectivity with reaction time for > 10 gaseous and liquid products, and recording mass flow rates, electrolyzer temperatures and pressures. The modular nature of our analytical system, combined with the standardized data pipeline, allows us to freely increase the number and type of sensors used with minimal impact on the data analysis time, as well as to multiplex our analysis to parallel electrolyzer cells, paving the way for a much deeper and faster understanding of the function of CO2RR catalysts, electrodes, and electrolyzers.

Design and first application of a novel laboratory reactor for alkali studies in chemical looping applications

Alkali compounds are readily released during biomass conversion and their complex interactions with reactor walls and sampling equipment makes detailed investigations challenging. This study evaluates a novel laboratory-scale fluidized bed reactor for chemical looping combustion (CLC) studies. The reactor design is based on detailed consideration of the behavior of alkali-containing molecules and aerosol particles and is guided by computational fluid dynamic simulations. The design allows for interactions between gaseous alkali and a fluidized bed, while minimizing alkali interactions with walls before and after the fluidized bed. The function of the laboratory reactor is demonstrated in experiments using online gas and alkali analysis. Alkali is continuously fed to the reactor as KOH or KCl aerosol with and without a fluidized bed of the oxygen carrier CaMn0.775Ti0.125Mg0.1O3-δ present in inert, reducing and oxidizing conditions at temperatures up to 900 °C. Alkali uptake by the OC is characterized in all conditions, and observed to sensitively depend on gas composition, reactor temperature and type of alkali compound. The experimental setup is concluded to have a significantly improved functionality compared to a previously used reactor, which opens up for detailed studies of interactions between alkali compounds and oxygen carriers used in CLC.

Online pressure and gas analysis of lithium-ion cells during abuse tests

Online pressure and gas analysis of lithium-ion cells during abuse tests Dr Carlos Ziebert, Leader of the Group Batteries – Calorimetry and Safety, KIT, explains how online venting gas analysis of batteries can be performed using a combination of battery calorimetry and online mass spectrometry. The main objective of the AnaLiBa project (Analytics of LithiumIon- Batteries) is the joint method development of a standardised sample handling process for the gas analysis of large cells by combining an accelerating rate calorimeter (ARC) and online mass spectrometry (MS). It is a part of the competence cluster Analytics/Quality Assurance (AQua) funded by the German Federal Ministry of Education and Research (BMBF). The Fraunhofer Institute for Chemical Technology coordinates the project.

Catalytic pyrolysis of waste printed circuit board with copper slag for the production of H2-rich gas

Co-pyrolysis of waste printed circuit boards (WPCB) and copper slag (CS) to generate high-value products is a promising approach in view of synergistic waste disposal and the circular economy. In this study, the catalytic pyrolysis of WPCB with CS to generate H2-rich gas (H2, CO, CH4, etc.) was proposed. The pyrolysis behavior of CS on WPCB was investigated by thermogravimetric analysis, and the pyrolysis gas release characteristics were determined by an online gas analyzer. The results showed that the catalytic effect of CS was weaker at low temperatures (500 °C). The minerals in CS were co-pyrolyzed with WPCB alone to explore the catalytic effect. Metal oxides increased the gas yield. The order of catalytic performance was CaO > Al2O3 > Fe3O4. This study clarified the catalytic influence of CS and its components on WPCB and provided insight into the application of synergistic treatment of two different solid wastes.

Kinetics study comparing bacterial growth and iron oxidation kinetics over a range of temperatures 5–45 °C

This comprehensive study summarizes kinetic data from experiments performed over a wide temperature range that overlaps the physiological operating temperature windows for most mesophilic Fe-oxidizers. Three acidophilic autotrophic bacterial strains Acidithiobacillus (At.) ferrivorans, At. ferrooxidans and Leptospirillum (L.) ferriphilum were investigated in this work in order to compare their growth and iron oxidation kinetics over a temperature range of 5–45 °C. On-line gas analysis was applied to determine the O2 and CO2 consumption rates during the culture incubation. Despite the genotypic differences these three strains share many common physiological traits. At t = 30 °C, the specific growth rate (μ) at all three species reached 0.11 h−1 which is equivalent to generation time 6.5 h. Maximum ferrous‑iron oxidation rate per unit of biomass was achieved with L. ferriphilum at t = 40 °C and approached 10 mmol Fe2+ (C-mmol) h−1. The temperature of incubation had a profound effect on the specific rates, while the kinetic parameter Ks/Ki at the Acidithiobacilli strains remained unaffected. Cultures with Leptospirillum incubated at temperatures >35 °C were capable of iron oxidation at redox potentials close to +950 mV and kept constant specific rates until Fe2+ depletion. The parameter Ks/Ki at L. ferriphilum was two order of magnitude lower than for the Acidithiobacilli. However, this feature disappears at temperatures below 30 °C, where Ks/Ki has a value comparable to Acidithiobacilli, which suggests that L. ferriphillum uses different Fe oxidation systems depending on temperature conditions. Strong correlation was observed between ferrous iron oxidation, and carbon dioxide fixation in the exponentially growing cultures with the yield coefficient (YSX) approaching 14 μmol C fixed per mmol Fe2+ oxidized. The kinetic parameters differed significantly between bacterial strains under “extreme” temperatures (t < 10 °C; t > 35 °C). All three bacterial strains were capable of oxidizing iron over the entire range (5–45 °C) of incubation temperatures. Neither At. ferrivorans nor At. ferrooxidans showed exponential growth at the temperature 40 °C. Bacterial iron oxidation not associated with growth was observed during incubation at 5 °C. At. ferrivorans, was the only species that can grow exponentially at a temperature of 5 °C. Moreover, it differed from the other species by greater sensitivity to low pH which seems to be more pronounced at temperatures t < 10 °C, with minimum of pH 1.9 for growth.

Synthesis and evaluation of novel and efficient Ni-based dual functional materials (DFMs) for integrated CO2 capture and hydrogenation

We report on the synthesis and evaluation of novel, highly active and stable bimetallic DFMs for simultaneous CO2 adsorption and subsequent hydrogenation to value added products. The DFMs contain various combinations of Ni (5–15 wt%) and Cu (5–15 wt%) with Na2O (5–15 wt%) as adsorbent supported on alumina (γ-Al2O3). The DFMs were synthesized via sequential incipient wetness impregnation method and were thoroughly characterized by combination of various surface sensitive and bulk sensitive analytical tools such as XRD, XPS, BET surface area, HR-TEM and H2-TPR. The DFMs were evaluated for CO2 capture and subsequent hydrogenation in a fixed-bed quartz tubular reactor connected with an online gas analyzer. The results demonstrated that at an operating temperature of 320℃, the DFM with a composition of 10 wt%Ni5wt%Cu/10 wt%Na2O.Al2O3 resulted in exceptionally high CO2 adsorption (310.84 μmol/g) and subsequent hydrogenation to methane (249.2 μmol CH4/gDFM). The XPS analysis revealed that this DFM contains comparatively larger percentage of highly ionized and/or induced Ni2+ as well as Cu+1 species. The results of H2-TPR also clearly indicated improvement in its reducibility. Moreover, the TEM analysis results revealed the presence of well-dispersed and smaller metal oxide particles in the bimetallic 10 wt%Ni5wt%Cu/10 wt%Na2O.Al2O3 DFM. In this regards, the exceptional high performance of the 10 wt%Ni5wt%Cu/10 wt%Na2O.Al2O3 DFM was attributed to the synergistic effects of the bimetallic combination of Ni with Cu resulting in enhanced physicochemical properties and thus demonstrated exceptionally higher performance.

On-line multi-gas component measurement in the mud logging process based on Raman spectroscopy combined with a CNN-LSTM-AM hybrid model

The qualitative and quantitative analysis of gas components extracted from drilling fluids during mud logging is essential for identifying drilling anomalies, reservoir characteristics, and hydrocarbon properties during oilfield recovery. Gas chromatography (GC) and gas mass spectrometers (GMS) are currently used for the online analysis of gases throughout the mud logging process. Nevertheless, these methods have limitations, including expensive equipment, high maintenance costs, and lengthy detection periods. Raman spectroscopy can be applied to the online quantification of gases at mud logging sites due to its in-situ analysis, high resolution, and rapid detection. However, laser power fluctuations, field vibrations, and the overlapping of characteristic peaks of different gases in the existing online detection system of Raman spectroscopy can affect the quantitative accuracy of the model. For these reasons, a gas Raman spectroscopy system with a high reliability, low detection limits, and increased sensitivity has been designed and applied to the online quantification of gases in the mud logging process. The near-concentric cavity structure is used to improve the signal acquisition module in the gas Raman spectroscopic system, thus enhancing the Raman spectral signal of the gases. One-dimensional convolutional neural networks (1D-CNN) combined with long- and short-term memory networks (LSTM) are applied to construct quantitative models based on the continuous acquisition of Raman spectra of gas mixtures. In addition, the attention mechanism is used to futher improve the quantitative model performance. The results indicated that our proposed method has the capability to continuously on-line detect 10 hydrocarbon and non-hydrocarbon gases in the mud logging process. The limitation of detection (LOD) for different gas components based on the proposed method are in the range of 0.0035%–0.0223%. Based on the proposed CNN-LSTM-AM model, the average detection errors of different gas components range from 0.899% to 3.521%, and their maximum detection errors range from 2.532% to 11.922%. These results demonstrate that our proposed method has a high accuracy, low deviation, and good stability and can be applied to the on-line gas analysis process in the mud logging field.

Investigation of hydrogen-rich syngas production from biomass gasification with CaO and steam based on real-time gas release behaviors

Real-time gas release behaviors in biomass gasification using steam and CaO under various operating conditions were investigated by on-line gas analysis to mechanistically understand the enhanced production of hydrogen-rich syngas. Without steam and CaO, the syngas yields increased from 146.6 mL/g at 600 °C to 831.5 mL/g at 850 °C with improved cold gas efficiency (CGE) but corresponding to a low H2/CO ratio of 0.14. By introducing steam with CaO, the syngas yield further increased to > 1000 mL/g with 4 times growth in H2/CO ratio, and the CGE increased to 71.6%. The release of H2 was prolonged and intensified with the synergistic use of steam and CaO, while CH4 and CO almost unchanged. The increase in steam/biomass ratio mainly contributed to the elevated releasing rate of H2 after 6 min, and the growth in CaO dosage led to improved H2 evolutions all through the reaction period where the peak was from 33.1 mL/min∙g without catalyst to ∼100 mL/min∙g under catalyst/biomass = 2. Ternary diagram analysis indicated that CaO and steam with higher addition amount (e.g., CaO/biomass = 1, steam/biomass = 7.5) were more suitable for producing hydrogen-rich syngas with less CO2 emission and the elevated CGE. These synergistic effects were possibly due to that CaO addition in the presence of steam can catalyze the volatiles cracking and absorb CO2 to drive the chemical equilibrium of steam reforming and water gas shift reactions shifting forward, which consequently facilitated H2 formation. The current work will provide fundamentals for efficient conversion of biomass waste to high quality syngas.

Influence of dynamic stretching on ankle joint stiffness, vertical stiffness and running economy during treadmill running.

The purpose of the present study was to investigate whether and how dynamic stretching of the plantarflexors may influence running economy. A crossover design with a minimum of 48 h between experimental (dynamic stretching) and control conditions was used. Twelve recreational runners performed a step-wise incremental protocol to the limit of tolerance on a motorised instrumented treadmill. The initial speed was 2.3 m/s, followed by increments of 0.2 m/s every 3 min. Dynamic joint stiffness, vertical stiffness and running kinematics during the initial stage of the protocol were calculated. Running economy was evaluated using online gas-analysis. For each participant, the minimum number of stages completed before peak O2 uptake (V̇O2peak) common to the two testing conditions was used to calculate the gradient of a linear regression line between V̇O2 (y-axis) and speed (x-axis). The number of stages, which ranged between 4 and 8, was used to construct individual subject regression equations. Non-clinical forms of magnitude-based decision method were used to assess outcomes. The dynamic stretching protocol resulted in a possible decrease in dynamic ankle joint stiffness (−10.7%; 90% confidence limits ±16.1%), a possible decrease in vertical stiffness (−2.3%, ±4.3%), a possibly beneficial effect on running economy (−4.0%, ±8.3%), and very likely decrease in gastrocnemius medialis muscle activation (−27.1%, ±39.2%). The results indicate that dynamic stretching improves running economy, possibly via decreases in dynamic joint and vertical stiffness and muscle activation. Together, these results imply that dynamic stretching should be recommended as part of the warm-up for running training in recreational athletes examined in this study.

Operando X‐ray Powder Diffraction Study of Mechanochemical Activation Tested for the CO Oxidation over Au@Fe2O3 as Model Reaction

AbstractMechanochemistry has proven to be an excellent green synthesis method for preparing organic, pharmaceutical, and inorganic materials. Mechanocatalysis, inducing a catalytic reaction by mechanical forces, is an emerging field because neither external temperature nor pressure inputs are required. Previous studies reported enhanced catalytic activity during the mechanical treatment of supported gold catalysts for CO oxidation. So far, the processes inside the milling vessel during mechanocatalysis could not be monitored. In this work, the results of high‐energy operando X‐ray powder diffraction experiments and online gas analysis will be reported. A specific milling setup with a custom‐made vessel and gas dosing system was developed. To prove the feasibility of the experimental setup for operando diffraction studies during mechanocatalysis, the CO oxidation with Au@Fe2O3 as a catalyst was selected as a well‐known model reaction. The operando studies enabled monitoring morphology changes of the support as well as changes in the crystallite size of the gold catalyst. The change of the crystal size is directly correlated to changes in the active surface area and thus to the CO2 yield. The studies confirm the successful implementation of the operando setup, and its potential to be applied to other catalytic reactions.

Design and operation of an industrial size adsorption-based cleaning system for biogas use in fuel cells

The use of biogas, one of the main players in the energy transition, requires the efficient removal of harmful traces of impurities. Reliable and robust purification systems are therefore required before the biogas is fed into cogeneration or upgrading plants.In this work, an industrial-scale biogas purification system for the deep removal of impurities is analysed. The experimental design phase in the laboratory and the subsequent evaluation of the system's performance in the field, are presented. The work was carried out as part of the DEMOSOFC project, where the first industrial-scale SOFC system was operated in a real wastewater treatment plant fed with sewage gas.The system is an adsorption-based plant that uses multiple sorbents. The on-site operation lasted more than 15,000 h and was used to analyse the performance with real sewage biogas. A continuous and innovative online gas analyser was also installed, and its measurements were verified with analyses from an external laboratory.The performance of the sorbents met the expectations measured in the laboratory. The loading rate – measured in % of the maximum loading rate of the sorbents – was 35% for H2S and 1.8% for siloxanes, confirming the optimal design of the purification unit.

Practical approach for an easy determination of the limit of detection and uncertainty budget associated with on-line measurements of gas and aerosols by ion chromatography

The Monitor for Aerosols and Gases in Ambient air (MARGA) is an on-line gas and aerosol sampling and analysis system based on ion chromatography (IC) that allows the monitoring at 1-h time resolution of major water-soluble atmospheric species in the gas phase (NH3, HCl, HONO, HNO3, SO2) and the particle phase (NH4+, Na+, K+, Ca2+, Mg2+, Cl−, NO3−, SO42−). The lack of a common procedure among users to determine the LOD and the uncertainty of measurements for each species led to the comparison of four different operational approaches for the LOD determination, one manual and three automatic. This comparison highlighted the high NO3− blank values around 0.6 μg m−3 when using a HNO3-based cation eluent, so the p-TSA-based eluent was proposed instead. A model for an easy estimation of measurement uncertainties is suggested based on main sources of uncertainty (liquid sample volume, air volume, representativeness of the sample, accuracy of the internal standard preparation, chemical background, repeatability), applied to a real dataset acquired in a rural site in the North of France. It gives relative average uncertainties between 5 and 30% for NH3, HONO, HNO3, SO2, NH4+ NO3− and SO42−, while Na+, K+, Ca2+, Mg2+ and Cl− range between 45% and >100%. A comparison between our dataset and other studies confirmed that the variation of the uncertainty budget depends on environmental concentrations of the species and site typology. The practical recommendations drawn in this paper may be helpful to the user community of gas and aerosol online samplers coupled to IC analysis.

Experimental study on dynamic release and transformation of sulfur during pyrolysis of Shanxi high-sulfur anthracites based on MFBRA and XPS

Pyrolytic desulfurization of two Shanxi high-sulfur anthracites was investigated experimentally under hydrogen atmospheres using a micro fluidized bed reaction analyzer (MFBRA), the dynamic release behavior of sulfur-containing gas during pyrolysis was characterized by a rapid online gas analyzer, and the transformation between sulfur-containing components in the resultant char was analyzed based on morphological and XPS characterizations. The results show that the dynamic release of sulfur-containing gas features two intensity peaks at 530–560 °C and 812–830 °C, respectively, indicating that the sulfur release proceeds by two subsequent processes: the reduction reaction of pyrite and the organic sulfur decomposition. The migration from inorganic to organic sulfur occurs predominately at lower temperatures, while the transformation between different forms of organic sulfur components is dominant at higher temperatures. Overall, the anthracite coal with a higher organic sulfur content has a higher sulfur removal efficiency in the hydrogen atmosphere. The research results provide the essential data supporting the development of highly efficient pyrolysis desulfurization technology for clean and efficient utilization of high sulfur anthracite coal resources.

Electrolyte Reactivity at the Charged Ni-Rich Cathode Interface and Degradation in Li-Ion Batteries.

The chemical and electrochemical reactions at the positive electrode–electrolyte interface in Li-ion batteries are hugely influential on cycle life and safety. Ni-rich layered transition metal oxides exhibit higher interfacial reactivity than their lower Ni-content analogues, reacting via mechanisms that are poorly understood. Here, we study the pivotal role of the electrolyte solvent, specifically cyclic ethylene carbonate (EC) and linear ethyl methyl carbonate (EMC), in determining the interfacial reactivity at charged LiNi0.33Mn0.33Co0.33O2 (NMC111) and LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes by using both single-solvent model electrolytes and the mixed solvents used in commercial cells. While NMC111 exhibits similar parasitic currents with EC-containing and EC-free electrolytes during high voltage holds in NMC/Li4Ti5O12 (LTO) cells, this is not the case for NMC811. Online gas analysis reveals that the solvent-dependent reactivity for Ni-rich cathodes is related to the extent of lattice oxygen release and accompanying electrolyte decomposition, which is higher for EC-containing than EC-free electrolytes. Combined findings from electrochemical impedance spectroscopy (EIS), TEM, solution NMR, ICP, and XPS reveal that the electrolyte solvent has a profound impact on the degradation of the Ni-rich cathode and the electrolyte. Higher lattice oxygen release with EC-containing electrolytes is coupled with higher cathode interfacial impedance, a thicker oxygen-deficient rock-salt surface reconstruction layer, more electrolyte solvent and salt breakdown, and higher amounts of transition metal dissolution. These processes are suppressed in the EC-free electrolyte, highlighting the incompatibility between Ni-rich cathodes and conventional electrolyte solvents. Finally, new mechanistic insights into the chemical oxidation pathways of electrolyte solvents and, critically, the knock-on chemical and electrochemical reactions that further degrade the electrolyte and electrodes curtailing battery lifetime are provided.

Systematic assessment of process analytical technologies for biologics.

The application of process analytical technology (PAT) for biotherapeutic development and manufacturing has been employed owing to technological, economic, and regulatory advantages across the industry. Typically, chromatographic, spectroscopic, and/or mass spectrometric sensors are integrated into upstream and downstream unit operations in in-line, on-line, or at-line fashion to enable real-time monitoring and control of the process. Despite the widespread utility of PAT technologies at various unit operations of the bioprocess, a holistic business value assessment of PAT has not been well addressed in biologics. Thus, in this study, we evaluated PAT technologies based on predefined criteria for their technological attributes such as enablement of better process understanding, control, and high-throughput capabilities; as well as for business attributes such as simplicity of implementation, lead time, and cost reduction. The study involved an industry-wide survey, where input from subject matter industry experts on various PAT tools were collected, assessed, and ranked. The survey results demonstrated on-line liquid Chromatography (LC), in-line Raman, and gas analysis techniques are of high business value especially at the production bioreactor unit operation of upstream processing. In-line variable path-length UV/VIS measurements (VPE), on-line LC, multiangle light scattering (MALS), and automated sampling are of high business value in Protein A purification and polishing steps of the downstream process. We also provide insights, based on our experience in clinical and commercial manufacturing of biologics, into the development and implementation of some of the PAT tools. The results presented in this study are intended to be helpful for the current practitioners of PAT as well as those new to the field to gauge, prioritize and steer their projects for success.

Simultaneous investigation of coal ignition and soot formation in two-stage O2/N2 and O2/CO2 atmospheres

Due to the intermittent nature of most renewable energy sources, the flexible oxy-coal combustion technology equipped with carbon capture, utilization, and storage (CCUS) will play an indispensable role in achieving carbon neutrality. In this work, we fundamentally investigated coal stream ignition and soot evolution in a series of staged O2/N2 and O2/CO2 atmospheres for two kinds of coal samples. A novel two-stage flat-flame burner can provide a controlled temperature (1500 K) and atmosphere that are comparable to those in practical boilers. We incorporated in-situ Mie scattering of coal particles, visible light of coal flame, laser-induced incandescence (LII) of soot, as well as online soot particle sampling (in combustion) and gas analysis (in pyrolysis). Compared with conventional O2/N2 atmosphere, the O2/CO2 case under the same oxygen fraction (XO2 = 0.3) substantially delays the ignition of coal streams (i.e., 10.1 ms for lignite and 8.9 ms for bituminous coal) on the more representative two-stage burner, and reduces soot volume fraction in the coal flame (i.e., by 26% for lignite and 48% for bituminous coal). The growth and oxidation of primary soot are retarded by the O2/CO2 ambience, which might be attributed to the lowered coal/char surface temperature and the smaller O2 diffusion coefficient in oxy-mode. In particular, we find that elevating oxygen fraction reduces soot volume fraction in the O2/N2 case, but exceptionally promotes soot formation in the O2/CO2 case. When the effect of coal rank is concerned, the bituminous coal ignites much later than the lignite due to less amount of combustible light gases released during pyrolysis. The lowered local temperatures in bituminous coal combustion lead to reduced soot forming ability in the O2/CO2 ambience, but in O2/N2 conditions, burning bituminous coal is sootier.

Acute Cardiorespiratory Responses to Different Exercise Modalities in Chronic Heart Failure Patients—A Pilot Study

The purpose of this study was to compare the acute cardiorespiratory responses and time spent above different %VO2peak intensities between three “iso-work” protocols: (a) a high intensity interval training protocol (HIIT), (b) a higher intensity continuous protocol (CON70) and (c) a lower intensity continuous protocol (CON50) in patients with chronic heart failure (CHF). Ten male CHF patients (aged 55.1 ± 16.2 years) performed in separate days a single session of a HIIT protocol consisted of 4 sets × 4 min cycling at 80% VO2peak with 3 min of recovery at 50% VO2peak, a CON70 protocol corresponding to 70% VO2peak and a CON50 protocol corresponding to 50% VO2peak. Cardiopulmonary data were collected by an online gas analysis system. The HIIT and CON70 elicited higher cardiorespiratory responses compared to CON50 with no differences between them (p > 0.05). In HIIT and CON70, patients exercised longer at >80% and >90% VO2peak. The completion rate was 100% for the three protocols. Not any adverse events were observed in either protocol. Both HIIT and CON70 elicited a stronger physiological stimulus and required shorter time than CON50. Both HIIT and CON70 also induced comparable hemodynamic responses and ventilatory demand.