Gas Analysis System Research Articles

A Portable and Autonomous Mass Spectrometric System for On-Site Environmental Gas Analysis.

We developed a portable mass spectrometric system ("miniRuedi") for quantificaton of the partial pressures of He, Ne (in dry gas), Ar, Kr, N2, O2, CO2, and CH4 in gaseous and aqueous matrices in environmental systems with an analytical uncertainty of 1-3%. The miniRuedi does not require any purification or other preparation of the sampled gases and therefore allows maintenance-free and autonomous operation. The apparatus is most suitable for on-site gas analysis during field work and at remote locations due to its small size (60 cm × 40 cm × 14 cm), low weight (13 kg), and low power consumption (50 W). The gases are continuously sampled and transferred through a capillary pressure reduction system into a vacuum chamber, where they are analyzed using a quadrupole mass spectrometer with a time resolution of ≲1 min. The low gas consumption rate (<0.1 mL/min) minimizes interference with the natural mass balance of gases in environmental systems, and allows the unbiased quantification of dissolved-gas concentrations in water by gas/water equilibration using membrane contractors (gas-equilibrium membrane-inlet mass spectrometry, GE-MIMS). The performance of the miniRuedi is demonstrated in laboratory and field tests, and its utility is illustrated in field applications related to soil-gas formation, lake/atmosphere gas exchange, and seafloor gas emanations.

Higher resolution helium measuring system for deuterium plasma on EAST tokamak via normal Penning gauge

Although the deuterium and helium have almost the same mass, a Penning Optical Gas Analyzer (POGA) system on the basis of the spectroscopic method and Penning discharging has been designed on EAST, since 2014. The POGA system was developed successfully in 2015, it was the first time that EAST could detect helium partial pressure in deuterium plasma (wall conditioning and plasma operation scenario). With dedicated calibration and proper adjustment of the parameters, the minimum concentration of helium in deuterium gas can be measured as about 0.5% instead of 1% on the other tokamak devices. Moreover, the He and D2 partial pressures are measured simultaneously. At present, the measurable range of deuterium partial pressure is 1 × 10−7 mbar to 1 × 10−5 mbar, meanwhile the range of helium is 1 × 10−8 mbar to 1 × 10−5 mbar. The measurable range can be modified by means of the adjustment of POGA system’s parameters. It is possible to detect the interesting part of the gas with a time resolution of less than 5 ms (the 200 ms because of conductance of transfer pipe at present). The POGA system was routinely employed to wall conditioning and helium enrichment investigation in 2015. Last but not the least, the low temperature plasma of POGA is generated by normal penning gauge Pfeiffer IKR gauge instead of Alcatel CF2P, which has been suspended for a few years and was used for almost all the POGA systems in the world.

Effects of a structured midsole on spatio-temporal variables and running economy in overground running

Research to enhance running performance has led to the design of a leaf spring-structured midsole shoe (LEAF). In treadmill running, it has been shown that LEAF led to an increased running economy and increased stride length (SL) through a horizontal foot shift during stance compared to a standard foam shoe (FOAM). The purpose of this study was to analyse whether (a) these findings can also be observed in overground running and (b) relations exist between spatio-temporal variables and running economy. Ten male long-distance heel-strike runners ran at their individual 2 mmol/l blood lactate speed with LEAF and FOAM in randomized order. Kinematic data were recorded with an inertial measurement unit synchronized with 2D video. Oxygen consumption was measured using an automated metabolic gas analysis system. Blood lactate was collected after each run. The strike pattern was unaffected by LEAF. SL was increased by 0.9 ± 1.1 cm (95% CI 0.2 to 1.5; p = .040; dz = 0.76), stride rate (SR) was reduced by −0.4 ± 0.3 strides/min (95% CI −0.6 to −0.1; p = .029; dz = 0.82) and oxygen consumption tended to be reduced by 1% (−0.4 ± 0.6 ml/min/kg; 95% CI −0.8 to 0.0; p = .082; dz = 0.62) when running with LEAF compared to FOAM. Changes in oxygen consumption in LEAF were correlated with SL (r = 0.71; p = .022) and SR (r = −0.68; p = .031). It can be concluded that LEAF has the potential to cause small changes in spatio-temporal variables during running. Runners increasing SL and decreasing SR in response to LEAF can achieve small improvements in running economy, which is beneficial in terms of performance.

A novel membrane inlet‐infrared gas analysis (MI‐IRGA) system for monitoring of seawater carbonate system

AbstractIncreased atmospheric CO2 concentrations are driving changes in ocean chemistry at unprecedented rates resulting in ocean acidification, which is predicted to impact the functioning of marine biota, in particular of marine calcifiers. However, the precise understanding of such impacts relies on an analytical system that determines the mechanisms and impact of elevated pCO2 on the physiology of organisms at scales from species to entire communities. Recent work has highlighted the need within experiments to control all aspects of the carbonate system to resolve the role of different inorganic carbon species on the physiological responses observed across taxa in real‐time. Presently however, there are limited options available for continuous quantification of physiological responses, coupled with real‐time calculation of the seawater carbonate chemistry system within microcosm environments. Here, we describe and characterise the performance of a novel pCO2 membrane equilibrium system (the Membrane Inlet Infra‐Red Gas Analyser, MI‐IRGA) integrated with a continuous pH and oxygen monitoring platform. The system can detect changes in the seawater carbonate chemistry and determine organism physiological responses, while providing the user with real‐time control over the microcosm system. We evaluate the systems control, response time and associated error, and demonstrate the flexibility of the system to operate under field conditions and within a laboratory. We use the system to measure physiological parameters (photosynthesis and respiration) for the corals Pocillipora damicornis and Porites cylindrica; in doing so we present a novel dataset examining the interactive role of temperature, light and pCO2 on the physiology of P. cylindrica.

Raman analyzer for sensitive natural gas composition analysis

Raman spectroscopy is of significant importance in industrial gas analysis due to its unique capability of quantitative multigas measurement, especially diatomics (N2 and H2), with a single laser. This paper presents the development of a gas analyzer system based on high pressure Raman scattering in a multipass Raman cell and demonstrates its feasibility for real-time natural gas analysis. A 64-pass Raman cell operated at elevated pressure (5 bar) is used to create multiplicative enhancement (proportional to number of passes times pressure) of the natural gas Raman signal. A relatively low power 532-nm continuous wave laser beam (200 mW) is used as the source and the signals are measured through a cooled charge-coupled device grating spectrometer (30-s exposure). A hybrid algorithm based on background-correction and least-squares error minimization is used to estimate gas concentrations. Individual gas component concentration repeatability of the order of 0.1% is demonstrated. Further, the applicability of the technique for natural gas analysis is demonstrated through measurements on calibrated gas mixtures. Experimental details, analyzer characterization, and key measurements are presented to demonstrate the performance of the technique.

Competition between H2O and CO2 during the gasification of Powder River Basin coal

Reaction kinetics of Powder River Basin coal gasification were measured in a modified drop tube fixed bed reactor, accompanied with a rapid response, real-time gas analysis system. The material was rapidly heated and quickly pyrolyzed, followed by a slow gasification with long residence time. Tests are done at 833°C and elevated pressure to 4atm. The conditions were chosen to minimize mass transfer restrictions, so that only surface reactions were measured. The experimental data was fitted using Langmuir-Hinshelwood models to describe both reaction kinetics and degree of surface saturation. CO2 addition into steam gasification, steam addition into CO2 gasification, and injection of steam into an in-progress CO2 gasification test were performed. We found a rarely observed competition mechanism, in which H2O molecules primarily occupy active sites when H2O and CO2 are both present. With sufficient steam partial pressure, the reaction rate in mixtures of H2O and CO2 is equal to steam reaction rate. A newly developed L-H type model was presented to describe this competition mechanism. This model contains a steam reaction rate term and a supplementary CO2 reaction rate term, and matches our experimental results.

Multi-component gas emission measurements of the active lava lake of Nyiragongo, DR Congo

Between 2007 and 2011 four measurement campaigns (June 2007, July 2010, June 2011, and December 2011) were carried out at the crater rim of Nyiragongo volcano, DR Congo. Nyiragongo is one of the most active volcanoes in Africa. The ground-based remote sensing technique Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS), which uses scattered sunlight, the in-situ Multi-Component Gas Analyzer System (Multi-GAS) and alkaline impregnated filter were simultaneously applied during all field trips. The bromine monoxide to sulfur dioxide (BrO/SO2) and carbon dioxide to sulfur dioxide (CO2/SO2) molar ratios were determined, among other ratios. During the different field trips variations of the level of the lava lake up to several tens of meters were observed during intervals of the order of minutes up to days and also between the years. The measured gas ratios presented covariations with the lava lake level changes. BrO/SO2 ratios and CO2/SO2 ratios showed similar behavior. Annual CO2/SO2 and BrO/SO2 average values are generally positively correlated. In June 2011 increased BrO/SO2 as well as increased CO2/SO2 ratios have been observed before a sudden decrease of the lava lake.Overall the Cl/S ratio, determined by filter-pack sampling, shows an increasing trend with time, which is accompanied by a decreasing sulfur dioxide flux, the later measured nearly continuously by automated MAX-DOAS instruments since 2004.Mean gas emission fluxes of CO2, Cl and ‘minimum-BrO’ fluxes are calculated using their ratio to SO2. The first two show an increase with time, in contrast to the SO2 fluxes.A simple conceptual model is proposed which can explain in particular the June 2011 data, but as well our entire data set. The proposed model takes up the idea of convective magma cells inside the conduit and the possible temporary interruption of part of the cycling. We propose than two alternatives to explain the observed gas emission variation: 1. It is assumed that the diffuse and fumarolic degassing could have significant influence on measured gas composition. The measured gas composition might rather represent a gas mixture of plume, diffuse and fumarolic degassing than only representing the volcanic plume. 2. It is proposed that the interruption of the convection has taken place in the upper part of the conduit and deep degassing of CO2 and bromine initially continues while mixing already with gas emissions from an ageing source, which is characterized by an already diminishing sulfur content. These complex process but as well as the gas mixing of different sources, could explain general features of our dataset, but can unfortunately neither be confirmed nor disproven by the data available today.

Is passive metatarsophalangeal joint stiffness related to leg stiffness, vertical stiffness and running economy during sub-maximal running?

This study examined whether passive metatarsophalangeal joints (MPJ) stiffness was associated with leg stiffness (Kleg) vertical stiffness (Kvert) and running economy (RE) during sub-maximal running. Nine male experienced runners underwent passive MPJ stiffness measurements in standing and sitting positions followed by sub-maximal running on an instrumented treadmill. With the individual foot position properly aligned, the MPJ passive stiffness in both sitting (MPJsit) and standing positions (MPJstand) were measured with a computerized dynamometer. Data were collected at a running speed of 2.78m/s, representing a stabilized level of energy expenditure. Pedar pressure insole was used to determine the contact time (tc) and peak reaction force for the calculation of Kleg and Kvert. A respiratory gas analysis system was used to estimate the RE. Bivariate correlation test was performed to examine the correlation among MPJ stiffness, contact time, Kleg, Kvert, and RE. The results showed that MPJsit and MPJstand were inversely correlated with RE (p=0.04, r=−0.68 to −0.69), suggesting that stiffer MPJ improves RE. In addition, MPJsit was correlated positively with Kleg (p<0.01, r=0.87),Kvert (p=0.03, r=0.70) but inversely with tc (p=0.02, r=−0.76), while MPJstand was correlated positively with the Kvert (p=0.02, r=0.77). These findings suggested that strength of toe plantar flexors provides stability and agility in the stance phase for more effective and faster forward movement.

Effects of plasma assisted combustion on pollutant emissions of a premixed flame of natural gas and air

The recently increasing interest in plasma assisted combustion is mainly motivated by new possibilities for ignition and flame stabilization, in addition to pollutant emission reduction and control. In a chemically active environment, the plasma generates radicals, excited chemical species and ions, thus increasing the combustion process reaction rate. In this paper, the effect of plasma assisted combustion on pollutant emissions of a premixed flame of natural gas and air is investigated by using two gas analyzer systems to acquire a diversity of pollutant gases. The plasma is created by using a gliding arc discharge at the equivalence ratios of ϕ=1.2 and 1.4, with applied electrical power ranging between 220W and 370W. The use of a gliding arc discharge leads to a reduction in the emissions of hydrocarbons and carbon monoxide. Meanwhile, the carbon dioxide emissions increase due to a faster oxidation of carbon monoxide and the water concentration in the exhaust gases is reduced with the use of plasma at the expense of higher hydrogen generation.

Experimental study on detailed emissions speciation of an HCCI engine equipped with a three-way catalytic converter

The purpose of the current study is to provide comprehensive quantitative data on hydrocarbon species concentrations in exhaust gases from a homogeneous charge compression ignition (HCCI) engine fuelled with gasoline. Additionally, the obtained results yielded assessment of the efficiency of a standard three-way catalytic converter (TWC) for this kind of engines. Experiments were performed on a single cylinder direct injection engine with ability to be operated in a negative valve overlap mode, to achieve HCCI combustion. The engine was run under variable operating conditions and mixture formation strategies, which provided different compositions of cylinder-out exhaust gases. Fourier transform infrared gas analytical system was used for measurements of exhaust gas compositions. The results showed how different control strategies and injection timings during NVO affect the compositions of unburnt hydrocarbons. To provide a baseline for HCCI results, the research engine was also operated in spark ignition combustion mode. Measurements of exhaust compositions upstream and downstream TWC revealed low conversion efficiency in terms of hydrocarbons oxidation for HCCI combustion. Obtained results indicate that besides reduction of regulated toxic compounds, emissions of specific hydrocarbons could be problematic in the light of future applications of HCCI combustion systems.

Sequestration of CO2 using Cu nanoparticles supported on spherical and rod-shape mesoporous silica

The CO2 sequestration is one of the most promising solutions to tackle global warming. In this study, spherical mesoporous silica particles (MPS-S) and rod-shaped mesoporous silica particles (MPS-R) loaded with Cu nanoparticles were selectively prepared and employed for CO2 adsorption. For the first time uniform Cu nanoparticles were incorporated into the rod-shaped mesoporous silica particles by post-synthesis modification using both N-[3-(trimethoxysilyl)propyl]ethylenediamine (PEDA) and ethylenediamine (EDA) as coupling agents. The physiochemical properties of the mesoporous and copper grifted silica composites were investigated by CHN elemental analysis, FTIR spectroscopy, thermogravimetric analysis, X-ray diffraction, energy dispersive X-ray spectroscopy (EDX), surface area analysis, scanning, transmission electron microscopy and gas analysis system (GSD 320, TERMO). The mesoporous silica shows highly ordered mesoporous structures, with the rod-shaped particles having a higher surface area than the spherical ones. Copper nanoparticles with an average diameter of 6.0nm were uniformly incorporated into the MPS-S and MPS-R. Moreover, Cu-loaded mesoporous silica exhibits up to 40% higher CO2 adsorption capacity than the bare MPS. The MPS-R modified with Cu nanoparticles showed a maximum CO2 adsorption capacity of 0.62mmol/g and the humidity showed a slight negative effect on CO2 uptake process. The enhancement of CO2 adsorption onto transition metal/mesoporous substrates provides basis for imminent CO2 sequestration.

A biologically-inspired multi-joint soft exosuit that can reduce the energy cost of loaded walking.

BackgroundCarrying load alters normal walking, imposes additional stress to the musculoskeletal system, and results in an increase in energy consumption and a consequent earlier onset of fatigue. This phenomenon is largely due to increased work requirements in lower extremity joints, in turn requiring higher muscle activation. The aim of this work was to assess the biomechanical and physiological effects of a multi-joint soft exosuit that applies assistive torques to the biological hip and ankle joints during loaded walking.MethodsThe exosuit was evaluated under three conditions: powered (EXO_ON), unpowered (EXO_OFF) and unpowered removing the equivalent mass of the device (EXO_OFF_EMR). Seven participants walked on an instrumented split-belt treadmill and carried a load equivalent to 30 % their body mass. We assessed their metabolic cost of walking, kinetics, kinematics, and lower limb muscle activation using a portable gas analysis system, motion capture system, and surface electromyography.ResultsOur results showed that the exosuit could deliver controlled forces to a wearer. Net metabolic power in the EXO_ON condition (7.5 ± 0.6 W kg−1) was 7.3 ± 5.0 % and 14.2 ± 6.1 % lower than in the EXO_OFF_EMR condition (7.9 ± 0.8 W kg−1; p = 0.027) and in the EXO_OFF condition (8.5 ± 0.9 W kg−1; p = 0.005), respectively. The exosuit also reduced the total joint positive biological work (sum of hip, knee and ankle) when comparing the EXO_ON condition (1.06 ± 0.16 J kg−1) with respect to the EXO_OFF condition (1.28 ± 0.26 J kg−1; p = 0.020) and to the EXO_OFF_EMR condition (1.22 ± 0.21 J kg−1; p = 0.007).ConclusionsThe results of the present work demonstrate for the first time that a soft wearable robot can improve walking economy. These findings pave the way for future assistive devices that may enhance or restore gait in other applications.Electronic supplementary materialThe online version of this article (doi:10.1186/s12984-016-0150-9) contains supplementary material, which is available to authorized users.

An Evaluation of Methodologies for Determining Delay Times in the Cone Calorimeter Fire Test

Abstract An important step in calibrating a cone calorimeter apparatus is the determination of gas delay times. Gas concentration measurements must be made simultaneously in time with the main combustion events and processes (i.e., ignition, changes in mass loss rate, smoke production, and observed phenomena) to produce accurate results from the test. The calibration methodology prescribed in ASTM E1354-14e1 does not specify direct measurement of the transit time of gases through the apparatus or the response time of the individual analyzers, instead estimating total delay time by relating the thermal lag in the stack thermocouple to the transient response of the gas analyzers. Other methods to account for gas delay times are used in practice, leading to varying opinions on the method that is most suitable for oxygen consumption calorimetry. Furthermore, studies have shown that analyzer delay times are not consistent test-to-test, but depend on both the characteristics of the gas analyzer and sampling system (gas transit time) and the rates of production or consumption of gaseous species during a particular test (analyzer response time). In the present work, a methodology was proposed for measuring analyzer delay times by injecting a gas mixture of known concentration into the cone calorimeter exhaust stream. Delay times were computed using various methods, including ASTM E1354 and gas injection, and were evaluated with a series of cone calorimeter tests on various materials. Gas delay times determined by the ASTM E1354 method were found to produce inconsistent results for the cone calorimeter used in this study; results were significantly improved when alternative criteria were applied to the method. The square wave method was found to produce very good results for specimens with heat release rates greater than 3 kW; however, delay times in carbon monoxide production were not well represented. The gas injection method was found to produce excellent results, closely tracking oxygen consumption, carbon monoxide production, and carbon dioxide production in time, and as a result, the derived heat release rate coincided with observed events.

Early atmospheric detection of carbon dioxide from carbon capture and storage sites

ABSTRACTThe early atmospheric detection of carbon dioxide (CO2) leaks from carbon capture and storage (CCS) sites is important both to inform remediation efforts and to build and maintain public support for CCS in mitigating greenhouse gas emissions. A gas analysis system was developed to assess the origin of plumes of air enriched in CO2, as to whether CO2 is from a CCS site or from the oxidation of carbon compounds. The system measured CO2 and O2 concentrations for different plume samples relative to background air and calculated the gas differential concentration ratio (GDCR = −ΔO2/ΔCO2). The experimental results were in good agreement with theoretical calculations that placed GDCR values for a CO2 leak at 0.21, compared with GDCR values of 1–1.8 for the combustion of carbon compounds. Although some combustion plume samples deviated in GDCR from theoretical, the very low GDCR values associated with plumes from CO2 leaks provided confidence that this technology holds promise in providing a tool for the early detection of CO2 leaks from CCS sites. Implications: This work contributes to the development of a cost-effective technology for the early detection of leaks from sites where CO2 has been injected into the subsurface to enhance oil recovery or to permanently store the gas as a strategy for mitigating climate change. Such technology will be important in building public confidence regarding the safety and security of carbon capture and storage sites.

Technical note: A facility for respiration measurements in cattle

A respiration system consisting of 4 climate-controlled chambers and 1 set of flowmeters and analyzers was constructed and validated. Each chamber had volume of 21.10m3 (3.68×2.56×2.24m) and was made from steel with double-glazed windows on either side enabling visual contact between animals. The chambers are independently climate-controlled and can maintain temperature and relative humidity in a range from 5 to 45°C and 30 to 80%, respectively. A flow generator and mass flowmeter continuously pull air from each chamber and a slight negative pressure inside the chamber is ensured. Air from all chambers and ambient air share a common gas analysis and data acquisition system for monitoring O2, CO2, and CH4 concentrations over the measurement period, with the cycle time set to 20min. Analyzers are regularly calibrated and the chambers have mean recoveries of 99.0 and 98.0% for CO2 and CH4, respectively. The chambers are equipped with infrared cameras and electronic feed and water bins for intake measurements, as well as sensors for monitoring animal position and heart rate. Data acquisition and analysis software is used to calculate the rate of consumption of O2 and production of CO2 and CH4. The dynamic respiration measurements are integrated with feed intake data and other sensors. The daily gas exchanges are estimated by integration to determine methane emission and heat production. We conducted a trial with 12 lactating 3/4 Holstein × 1/4 Gyr crossbred dairy cows (6 multiparous and 6 primiparous) under 2 feeding regimens (ad libitum or restricted) to validate the system. Two 22-h respiration measurements were obtained from each cow. Restricted-fed cows showed lower values for milk yield, methane emission, and heat production compared with ad libitum-fed animals. We found no difference between groups for CH4 produced per kilogram of dry matter intake. Repeatability for CH4 emission and heat production was high (0.97 and 0.92, respectively). The respiration system described herein is a useful tool for measuring the dynamic and accumulated data of heat production, methane emission, and feed intake.

On-line analysis of organic emissions from residential wood combustion with single-photon ionisation time-of-flight mass spectrometry (SPI-TOFMS)

A study about the temporal variation of organic emissions from a modern wood log fired masonry heater was carried out with different gas analysis techniques: single-photon ionisation time-of-flight mass spectrometry (SPI-TOFMS) for real-time analysis of volatile (VOC), intermediate-volatile (IVOC) and semi-volatile organic compounds (SVOC), and a gas analyser system for gaseous components CO2, CO, NOx and organic gaseous carbon (OGC, quantified by flame ionisation detector). The emissions of three in Europe common types of firewood (beech, birch and spruce) were investigated by combustion of six consecutive batches of 2.5kg each over 4h. Batchwise emissions and temporal variations during combustion were discussed. Emission factors over the whole combustion cycle for OGC, VOC and IVOC were right up to one order of magnitude lower than in many previous studies due to latest improvements of air staging technology in wood log fired masonry heaters, whereas CO and NOx remained comparable. Regarding each combustion experiment, more than 50% of the total intensity of the mass spectra occurred during the combustion of the first two batches. Moreover, the molecular signatures of burning phases (‘ignition’, ‘stable combustion’ and ‘ember’) were examined by using non-negative matrix factorisation (NMF) and principal component analysis (PCA) in sequence. Marker substances for wood or biomass combustion, such as phenolic species or furan derivatives, exhibited highest relative abundance during ‘stable combustion’, whereas ‘ember’ is distinctly characterised by polyunsaturated hydrocarbons, such as benzene or naphthalene, through pyrosynthesis; in ‘ignition’, secondary decomposition products dominated. Nevertheless, highest quantitative emissions always occurred during ‘ignition’ at the beginning of each batch, followed by the phases ‘ember’ and ‘stable combustion’.

Aqueous Mesocosm Techniques Enabling the Real-Time Measurement of the Chemical and Isotopic Kinetics of Dissolved Methane and Carbon Dioxide.

Previous studies of microbially mediated methane oxidation in oceanic environments have examined the many different factors that control the rates of oxidation. However, there is debate on what factor(s) are limiting in these types of environments. These factors include the availability of methane, O2, trace metals, nutrients, the density of cell population, and the influence that CO2 production may have on pH. To look at this process in its entirety, we developed an automated mesocosm incubation system with a Dissolved Gas Analysis System (DGAS) coupled to a myriad of analytical tools to monitor chemical changes during methane oxidation. Here, we present new high temporal resolution techniques for investigating dissolved methane and carbon dioxide concentrations and stable isotopic dynamics during aqueous mesocosm and pure culture incubations. These techniques enable us to analyze the gases dissolved in solution and are nondestructive to both the liquid media and the analyzed gases enabling the investigation of a mesocosm or pure culture experiment in a completely closed system, if so desired.

Novel micro-reactor flow cell for investigation of model catalysts using in situ grazing-incidence X-ray scattering.

The design, fabrication and performance of a novel and highly sensitive micro-reactor device for performing in situ grazing-incidence X-ray scattering experiments of model catalyst systems is presented. The design of the reaction chamber, etched in silicon on insulator (SIO), permits grazing-incidence small-angle X-ray scattering (GISAXS) in transmission through 10 µm-thick entrance and exit windows by using micro-focused beams. An additional thinning of the Pyrex glass reactor lid allows simultaneous acquisition of the grazing-incidence wide-angle X-ray scattering (GIWAXS). In situ experiments at synchrotron facilities are performed utilizing the micro-reactor and a designed transportable gas feed and analysis system. The feasibility of simultaneous in situ GISAXS/GIWAXS experiments in the novel micro-reactor flow cell was confirmed with CO oxidation over mass-selected Ru nanoparticles.

Packed Bed Chemical Looping Platform: Design and Operation of 30 kWth Pilot Unit

Chemical looping combustion is a novel flameless combustion, where the conventional combustion is divided into reducer and oxidizer with assistance of the oxygen carrier. Due to its instinctive CO2 separation, high efficient and environmental-friendly property, chemical looping combustion attains more concerns. Large-scale experimental unit is a vital to chemical looping combustion, especially the commercial development. The reactor configuration of the worldwide pilot units are fluidized bed or moving bed, and the pilot unit with packed bed has not been reported. In this study, the pilot scale chemical looping packed bed unit with a nominal thermal capacity of 30kWth is designed on the basis of previous laboratory scale investigation. The pilot unit includes four parts, which is gas system, reaction system, tail gas treatment and gas analysis system, and auxiliary electrical system. The pilot packed bed reactor is made from 310s stainless steel tube with a 0.089 m o.d., a 0.079 m i.d., and 2.0 m height. A K-type thermocouple with 13 measurement points is located at the center of the packed bed reactor to obtain the axial temperature profile. The packed bed chemical looping platform is constructed to demonstrate the feasibility of generating high purity hydrogen from syngas derived from biomass wastes with on-site carbon capture. Two testing runs were presented using 5mm × 4-6mm cylindrical oxygen carriers comprising of 50wt % iron oxide (Fe2O3). The pure CO and the mixture of CO and H2 with a flow of 15 SLPM are the fuels of the two tests. The first test resulted in a full CO conversion with a 25.0% conversion of the oxygen carriers during reduction, the production of 3.82mol hydrogen with an average purity of 98.0%, and the maximum temperature rise is 219K during air combustion. The second test leaded to a full fuel conversion with a 35.7% conversion of the oxygen carriers during reduction, the production of 4.67mol hydrogen with an average purity of 98.0%, and the maximum temperature rise is 290K during air combustion. The two testing runs, the first operation of packed bed chemical looping pilot unit, supported syngas-based chemical looping application for hydrogen and power co-generation with in suit carbon capture and also demonstrated the design of the 30kWth pilot chemical looping platform with packed bed reactor.

The Spatial Distribution of Absolute Skeletal Muscle Deoxygenation During Ramp-Incremental Exercise Is Not Influenced by Hypoxia.

Time-resolved near-infrared spectroscopy (TRS-NIRS) allows absolute quantitation of deoxygenated haemoglobin and myoglobin concentration ([HHb]) in skeletal muscle. We recently showed that the spatial distribution of peak [HHb] within the quadriceps during moderate-intensity cycling is reduced with progressive hypoxia and this is associated with impaired aerobic energy provision. We therefore aimed to determine whether reduced spatial distribution of skeletal muscle [HHb] was associated with impaired aerobic energy transfer during exhaustive ramp-incremental exercise in hypoxia. Seven healthy men performed ramp-incremental cycle exercise (20 W/min) to exhaustion at 3 fractional inspired O2 concentrations (FIO2): 0.21, 0.16, 0.12. Pulmonary O2 uptake ([Formula: see text]) was measured using a flow meter and gas analyser system. Lactate threshold (LT) was estimated non-invasively. Absolute muscle deoxygenation was quantified by multichannel TRS-NIRS from the rectus femoris and vastus lateralis (proximal and distal regions). [Formula: see text] and LT were progressively reduced (p<0.05) with hypoxia. There was a significant effect (p<0.05) of FIO2 on [HHb] at baseline, LT, and peak. However the spatial variance of [HHb] was not different between FIO2 conditions. Peak total Hb ([Hbtot]) was significantly reduced between FIO2 conditions (p<0.001). There was no association between reductions in the spatial distribution of skeletal muscle [HHb] and indices of aerobic energy transfer during ramp-incremental exercise in hypoxia. While regional [HHb] quantified by TRS-NIRS at exhaustion was greater in hypoxia, the spatial distribution of [HHb] was unaffected. Interestingly, peak [Hbtot] was reduced at the tolerable limit in hypoxia implying a vasodilatory reserve may exist in conditions with reduced FIO2.