Gas Analysis System Research Articles

Automation of Gas Analyzer at Converter Shop in Steel Melt Shop

The main objective of the project “Automation of Gas Analyzers at Converter shop in Steel Melt Shop” is to analyze the concentration of CO, CO2, H2 and O2 present in the converter gas at different locations namely Dry Gas Analyzer, Wet Gas Analyzer and Common Wet Gas Analyzer which is released as a result of BLOWING process. The measurement of CO concentration in Dry Gas Analyzer is important for the Gas Recovery, storage and distribution of Gas to different customers for heating of Furnaces. The measurement of CO2 concentration in Dry Gas Analyzer is important to control the entry of air into the system and also for reducing the excessive heat generated in the Gas duct. The measurement of H2 concentration in Dry Gas Analyzer is important to know the leakages of water into the Converter to prevent explosion by stopping the blow. The measurement of O2 concentration in Wet Gas Analyzer and Common Wet Gas Analyzer is important to control the entry of air into the system and also to prevent formation of explosive mixture in the system leading to unsafe conditions like a massive explosion, if the percentage of oxygen goes beyond 2%. From the ID Fan the Gas is sent either to the Flare stack for flaring or to the Gas Holder for storing the gas based on CO concentration(CO>30% and O2<2%).The release gas is sampled before scrubber in hot condition by Dry Gas Analyzer system to measure CO,CO2&H2 concentrations. The gas concentration after ID Fan before flare stack is measured using Wet Gas Analyzer to measure concentration of Oxygen percentage. The Common Wet Gas Analyzer is installed in the common gas duct to Gas recovery plant to measure concentration of Oxygen percentage to prevent air entry into the gas holder and to stop the blowing process and gas recovery in case O2 concentration is above 2%.

3A1-E04 呼気ガス分析のためのサンプル採取装置の開発(医療ロボティクス・メカトロニクス(1))

3A1-E04 呼気ガス分析のためのサンプル採取装置の開発(医療ロボティクス・メカトロニクス(1))

Ammonia detection by a novel Pyrex microsystem based on thermal creep phenomenon

Our research work aims to develop a microfluidic system for gas analysis by using an original principle of integrated pumping. This microsystem can detect ammonia and the gas flow parameters inside the channel can be also controlled. The proposed microdevice consists in a microchannel including an integrated gas sensor with a heater. The trioxide tungsten (WO3) is implemented as a sensitive layer. The integrated heater is used for two reasons: to optimize the sensor response and to induce the gas pumping inside the microchannel by thermal creep phenomenon, therefore, no external pumping system is required. The study of the pumping effect generation has been realized by thermal and microfluidic simulations. Thermal simulations have been performed to estimate the thermal gradient along the microchannel. In addition, the microfluidic modeling allows us to determine the mass flow rate for different thermal gradient profiles, obtained from the thermal simulations. Finally, a complete Pyrex microsystem has been realized to detect ammonia. The existence of the thermal pumping has been demonstrated experimentally.

Blood Lactate Concentrations are Mildly Affected by Mobile Gas Exchange Measurements

We sought to investigate the effects of wearing a mobile respiratory gas analysis system during a treadmill test on blood lactate (bLa) concentrations and commonly applied bLa thresholds. A total of 16 recreational athletes (31±3 years, VO2max: 58±6 ml · min(-1) · kg(-1)) performed one multistage treadmill test with and one without gas exchange measurements (GEM and noGEM). The whole bLa curve, the lactate threshold (LT), the individual anaerobic thresholds according to Stegmann (IATSt) and Dickhuth (IATDi), and a fixed bLa concentration of 4 mmol ∙ l(-1) (OBLA) were evaluated. The bLa curve was shifted slightly leftward in GEM compared to noGEM (P<0.05), whereas the heart rate response was not different between conditions (P=0.89). There was no difference between GEM and noGEM for LT (2.61±0.34 vs. 2.64±0.39 m · s(-1), P=0.49) and IATSt (3.47±0.42 vs. 3.55±0.47 m · s(-1), P=0.12). However, IATDi (3.57±0.39 vs. 3.66±0.44 m · s(-1), P<0.01) and OBLA (3.85±0.46 vs. 3.96±0.47 m · s(-1), P<0.01) occurred at slower running velocities in GEM. The bLa response to treadmill tests is mildly affected by wearing a mobile gas analysis system. This also applies to bLa thresholds located at higher exercise intensities. While the magnitude of the effects is of little importance for recreational athletes, it might be relevant for elite athletes and scientific studies.

The energy demands of portable gas analysis system carriage during walking and running

The aim of this study was to evaluate the carriage of a portable gas analyser during prolonged treadmill exercise at a variety of speeds. Ten male participants completed six trials at different speeds (4, 8 and 12 km h− 1) for 40 min whilst wearing the analyser (P) or where the analyser was externally supported (L). Throughout each trial, respiratory gases, heart rate (HR), perceptions of effort and energy expenditure (EE) were measured. Significantly higher EE occurred during P12 (p = 0.01) than during L12 (855.3 ± 104.3; CI = 780.7–930.0 and 801.5 ± 82.2 kcal; CI = 742.7–860.3 kcal, respectively), but not at the other speeds; despite this, perceptions of effort and HR responses were unaffected. This additional EE is likely caused by alterations to posture which increase oxygen demand. The use of such systems is unlikely to affect low-intensity tasks, but researchers should use caution when interpreting data, particularly when exercise duration exceeds 30 min and laboratory-based analysers should be used where possible.

Effect of chewing speed on energy expenditure in healthy subjects

Objective. The aim of the study was to investigate the effect of rate of chewing on energy expenditure in human subjects. Materials and methods. Fourteen healthy subjects (aged 18–24 years) within the normal range of BMI participated in a cross-over experiment consisting of two 6-min sessions of gum chewing, slow (∼60 cycles/min) and fast (∼120 cycles/min) chewing. The resting energy expenditure (REE) and during gum chewing was measured using a ventilated hood connected to a gas analyzer system. The normality of data was explored using the Shapiro-Wilk test. The energy expenditure rate during chewing and the energy expenditure per chewing cycle were compared between the two chewing speeds using Wilcoxon signed ranks tests. Results. The energy expenditure per chewing cycle during slow chewing (median 1.4, range 5.2 cal; mean 2.1±1.6 cal) was significantly higher than that during fast chewing (median 0.9, range 2.2 cal; mean 1.0±0.7 cal) (p < 0.005). However, the energy expenditure rate was not significantly different between the two chewing speeds (p > 0.05). Conclusions. The results of this study suggest that chewing at a slower speed could increase the energy expenditure per cycle and might affect the total daily energy expenditure.

The Effects of Carbohydrate Loading 48 Hours Before a Simulated Squash Match

The aim of this study was to ascertain whether a high carbohydrate diet in the days before movement patterns simulating a squash match would increase carbohydrate oxidation during the match, and alter physical performance. Nine New Zealand level squash players were recruited to complete a simulated squash match on two occasions: 1) following a 48-hr high carbohydrate (11.1g·kg-1); and 2) following a calorie-matched low carbohydrate (2.1 g·kg-1) diet. The interventions were assigned in a randomized, single-blind, cross-over design. The match simulation was designed to mimic a five-game match lasting approximately 1 hr. Performance was measured as time to complete each game. Expired respiratory gases and heart rate were continuously collected throughout the trial using a portable gas analysis system. Capillary blood glucose and lactate samples were obtained during a 90 s rest period between each game. Rating of perceived exertion was also recorded after each set. Respiratory exchange ratio was significantly higher during exercise following the high CHO diet (0.80 vs. 0.76) p < .001) and this was associated with significantly faster time to complete the games (2340 ± 189 s vs. 2416 ± 128 s, p = .036). Blood glucose and lactate concentrations were also significantly higher in the high carbohydrate condition (p = .038 and p = .021 respectively). These results suggest that ingestion of a diet high in carbohydrate (>10 g/kg body weight) preceding simulated competitive squash produces increased rates of carbohydrate oxidation and maintains higher blood glucose concentrations. These metabolic effects were associated with improved physical performance.

Isotope exchange between gaseous hydrogen and uranium hydride powder

Isotope exchange between gaseous hydrogen and solid uranium hydride has been studied by flowing hydrogen (deuterium) gas through packed powder beds of uranium deuteride (hydride). We used a residual gas analyzer system to perform real-time analysis of the effluent gas composition. We also developed an exchange and transport model and, by fitting it to the experimental data, extracted kinetic parameters for the isotope exchange reaction. Our results suggest that, from approximately 70 to 700kPa and 25 to 400°C, the gas-to-solid exchange rate is controlled by hydrogen and deuterium transport within the ∼0.7μm diameter uranium hydride particles. We use our kinetic parameters to show that gas chromatographic separation of hydrogen and deuterium using uranium hydride could be feasible.

Slowed oxygen uptake kinetics in hypoxia correlate with the transient peak and reduced spatial distribution of absolute skeletal muscle deoxygenation

It remains unclear whether an overshoot in skeletal muscle deoxygenation (HHb; reflecting a microvascular kinetic mismatch of O2 delivery to consumption) contributes to the slowed adjustment of oxidative energy provision at the onset of exercise. We progressively reduced the fractional inspired O2 concentration (F(I,O2)) to investigate the relationship between slowed pulmonary O2 uptake (V(O2)) kinetics and the dynamics and spatial distribution of absolute[HHb]. Seven healthy men performed 8 min cycling transitions during normoxia (F(I,O2) = 0.21),moderate hypoxia (F(I,O2) = 0.16) and severe hypoxia (F(I,O2)= 0.12). V(O2) uptake was measured using a flowmeter and gas analyser system. Absolute [HHb] was quantified by multichannel,time-resolved near-infrared spectroscopy from the rectus femoris and vastus lateralis (proximal and distal regions), and corrected for adipose tissue thickness. The phase II V(O2) time constant was slowed (P <0.05) as F(I,O2) decreased (normoxia, 17 ± 3 s;moderate hypoxia, 22 ± 4 s; and severe hypoxia, 29 ± 9 s). The [HHb] overshoot was unaffected by hypoxia, but the transient peak [HHb] increased with the reduction in F(I,O2) (P <0.05). Slowed V(O2) kinetics in hypoxia were positively correlated with increased peak [HHb] in the transient (r(2) = 0.45; P <0.05), but poorly related to the [HHb] overshoot. A reduction of spatial heterogeneity in peak [HHb]was inversely correlated with slowed V(O2) kinetics (r(2) = 0.49; P <0.05). These data suggest that aerobic energy provision at the onset of exercise may be limited by the following factors: (i) the absolute ratio (i.e. peak [HHb]) rather than the kinetic ratio (i.e. [HHb] overshoot) of microvascular O2 delivery to consumption; and (ii) a reduced spatial distribution in the ratio of microvascular O2 delivery to consumption across the muscle.

Flow-based ammonia gas analyzer with an open channel scrubber for indoor environments

A robust and fully automated indoor ammonia gas monitoring system with an open channel scrubber (OCS) was developed. The sample gas channel dimensions, hydrophilic surface treatment to produce a thin absorbing solution layer, and solution flow rate of the OCS were optimized to connect the OCS as in-line gas collector and avoid sample humidity effects. The OCS effluent containing absorbed ammonia in sample gas was injected into a derivatization solution flow. Derivatization was achieved with o-phthalaldehyde and sulfite in pH 11 buffer solution. The product, 1-sulfonateisoindole, is detected with a home-made fluorescence detector. The limit of detection of the analyzer based on three times the standard deviation of baseline noise was 0.9ppbv. Sample gas could be analyzed 40 times per hour. Furthermore, relative humidity of up to 90% did not interfere considerably with the analyzer. Interference from amines was not observed. The developed gas analysis system was calibrated using a solution-based method. The system was used to analyze ammonia in an indoor environment along with an off-site method, traditional impinger gas collection followed by ion chromatographic analysis, for comparison. The results obtained using both methods agreed well. Therefore, the developed system can perform on-site monitoring of ammonia in indoor environments with improved time resolution compared with that of other methods.

Effect of Shoes' Heel Height on the Energy Cost during Jogging

The purpose of this study is to examine the changes of energy cost during a high-heeled continuous jogging. Thirteen healthy female volunteers jointed in this study with heel height of the shoes varied from 1, 4.5 and 7 cm, respectively. Each subjects jogged on the treadmill with K4b2 portable gas analysis system. The results of this study showed that ventilnation, relative oxygen consumption and energy expenditure increased with the increase of heel height and these values shows significantly larger when the heel height reached to 7 cm. Present study suggest that wearing high heel shoes jogging could directly increase energy consumption, causing neuromuscular fatigue.

Evaluation of a new JMA aircraft flask sampling system and laboratory trace gas analysis system

Abstract. We established and evaluated a flask air sampling system on a cargo C-130H aircraft, as well as a trace gas measurement system for the flask samples, as part of a new operational monitoring program of the Japan Meteorological Agency (JMA). Air samples were collected during each flight, between Kanagawa Prefecture (near Tokyo) and Minamitorishima (an island located nearly 2000 km southeast of Tokyo), from the air-conditioning system on the aircraft. Prior to the operational employment of the sampling system, a quality assurance test of the sampled air was made by specially coordinated flights at a low altitude of 1000 ft over Minamitorishima and comparing the flask values with those obtained at the surface. Based on our storage tests, the flask samples remained nearly stable until analyses. The trace gas measurement system has, in addition to the nondispersive infrared (NDIR) and vacuum ultraviolet resonance fluorescence (VURF) analyzers, two laser-based analyzers using wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) and off-axis integrated cavity output spectroscopy (ICOS). Laboratory tests of the laser-based analyzers for measuring flask samples indicated relatively high reproducibility with overall precisions of less than ±0.06 ppm for CO2, ±0.68 ppb for CH4, ±0.36 ppb for CO, and ±0.03 ppb for N2O. Flask air sample measurements, conducted concurrently on different analyzers were compared. These comparisons showed a negligible bias in the averaged measurements between the laser-based measurement techniques and the other methods currently in use. We also estimated that there are no significant isotope effects for CH4, CO and N2O using standard gases with industrial isotopic compositions to calibrate the laser-based analyzers, but CO2 was found to possess isotope effects larger than its analytical precision.

Evaluation of a new blood gas analysis system: RapidPoint 500®

We present here evaluation of a new blood gas analysis system, RapidPoint 500(®) (Siemens Healthcare Diagnostics). The aim of this research was to compare the ergonomics and analytical performances of this analyser with those of the RapidLab 1265 for the following parameters: pH, partial oxygen pressure, partial carbon dioxide pressure, sodium, potassium, ionized calcium, lactate and the CO-oximetry parameters: hemoglobin, oxyhemoglobin, carboxyhemoglobin, methemoglobin, reduced hemoglobin, neonatal bilirubin; as well as with the Dimension Vista 500 results for chloride and glucose. The Valtec protocol, recommended by the French Society of Clinical Biology (SFBC), was used to analyze the study results. The experiment was carried out over a period of one month in the Department of medical biochemistry. One hundred sixty five samples from adult patients admitted to the ER or hospitalized in intensive care were tested. The RapidPoint 500(®) was highly satisfactory from an ergonomic point of view. Intra-and inter- assay coefficients of variation (CV) with the three control levels were below those recommended by the SFBC for all parameters, and the comparative study gave coefficients of determination higher than 0.91. Taken together, the RapidPoint 500(®) appears fully satisfactory in terms of ergonomics and analytical performance.

Tunable Diode Laser Based Concentration Measurements of Water Vapour and Methane on a Solid Oxide Fuel Cell

This paper presents concentration measurements of water vapour and methane, taken in-situ on an operational solid oxide fuel cell (SOFC) test rig using tunable diode laser spectroscopy (TDLS). Methane concentration measurements are presented for the TDLS system and are compared with concentration measurements taken using gas chromatography (GC). Furthermore, purge times for the SOFC gas-analysis system have been calculated using TDLS, which are measurements that cannot be obtained directly using GC. Finally, water vapour concentration measurements in the SOFC cathode are shown for different system operating conditions: a dry cathode cycle and during the introduction of water vapour. As GC cannot be used to measure water vapour in the SOFC cathode stream, a direct comparison cannot be made with the TDLS measurements.

High Precision Evaluation of Gas Composition and Current Efficiency for High Temperature H2O and CO2 Electrolysis

A method to evaluate current efficiency was developed for high temperature electrolysis using solid oxide cells (SOECs). For a fuel electrode, depending on range, our gas analysis system achieved ±0.4-0.6% uncertainty for 10-90% mole fraction analysis of H2 and H2O. For an air electrode, O2 and N2 was measured with ± 0.2% and ±0.4% uncertainty, respectively. Case studies for both electrodes clarified that current efficiency can be evaluated with ±1.1-2.8% uncertainty at practical 90-50% steam utilizations in the case of ± 1.0% uncertainty in gas-flow-rate measurement.

Reference values for the incremental shuttle walk test in healthy subjects: from the walk distance to physiological responses

OBJECTIVE: To determine reference values for incremental shuttle walk distance (ISWD) and peak physiological responses during the incremental shuttle walk test (ISWT), as well as to develop a series of predictive equations for those variables in healthy adults. METHODS: We evaluated 103 healthy participants ≥ 40 years of age (54 women and 49 men). We fitted each participant with a gas analysis system for use during the ISWT. Oxygen consumption (VO2), carbon dioxide production, minute ventilation, heart rate (HR), ISWD, and maximal walking velocity (MWV) were obtained as primary outcomes. We also assessed hand grip strength (HGS) and lean body mass (LBM). RESULTS: The regression analysis models, including physiological variables, ISWD, and MWV (adjusted for age, body mass, height, and sex), produced R2 values ranging from 0.40 to 0.65 (for HR and peak VO2, respectively). Using the models including LBM or HGS, we obtained no significant increase in the R2 values for predicting peak VO2, although the use of those models did result in slight increases in the R2 values for ISWD and MWV (of 8% and 12%, respectively). The variables ISWD, MWV, and ISWD × body mass, respectively, explained 76.7%, 73.3%, and 81.2% of peak VO2 variability. CONCLUSIONS: Our results provide reference values for ISWD and physiological responses to the ISWT, which can be properly estimated by determining simple demographic and anthropometric characteristics in healthy adults ≥ 40 years of age. The ISWT could be used in assessing physical fitness in the general adult population and in designing individualized walking programs.

A centrifugal ice microtome for measurements of atmospheric CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; on air trapped in polar ice cores

Abstract. For atmospheric CO2 reconstructions using ice cores, the technique to release the trapped air from the ice samples is essential for the precision and accuracy of the measurements. We present here a new dry extraction technique in combination with a new gas analytical system that together show significant improvements with respect to current systems. Ice samples (3–15 g) are pulverised using a novel centrifugal ice microtome (CIM) by shaving the ice in a cooled vacuum chamber (−27 °C) in which no friction occurs due to the use of magnetic bearings. Both, the shaving principle of the CIM and the use of magnetic bearings have not been applied so far in this field. Shaving the ice samples produces finer ice powder and releases a minimum of 90% of the trapped air compared to 50%–70% when needle crushing is employed. In addition, the friction-free motion with an optimized design to reduce contaminations of the inner surfaces of the device result in a reduced system offset of about 2.0 ppmv compared to 4.9 ppmv. The gas analytical part shows a higher precision than the corresponding part of our previous system by a factor of two, and all processes except the loading and cleaning of the CIM now run automatically. Compared to our previous system, the complete system shows a 3 times better measurement reproducibility of about 1.1 ppmv (1 σ) which is similar to the best reproducibility of other systems applied in this field. With this high reproducibility, no replicate measurements are required anymore for most future measurement campaigns resulting in a possible output of 12–20 measurements per day compared to a maximum of 6 with other systems.

The upper limit of the cardiorespiratory training zone (40–84%HRR) is overestimated for postmenopausal women

The purpose of this study was to examine the heart rate reserve (HRR) at first and second ventilatory thresholds (VT's) in postmenopausal women and compare it with optimal intensity range recommended by the ACSM (40-84%HRR). An additional aim was to evaluate whether a higher aerobic power level corresponded to a higher HRR at VT's. Fifty-eight postmenopausal women participated in this study (aged 48-69). A graded 25 Wmin(-2) cycle ergometer (Monark E839) exercise protocol was performed in order to assess aerobic power. The heart rate and gas-exchange variables were measured continuously using a portable gas analyzer system (Cosmed K4b). The first (VT1) and the second (VT2) VT's were determined by the time course curves of ventilation and O2 and CO2 ventilatory equivalents. A K-means clustering analysis was used in order to identify VO2max groups (cut-off of 30.5 mlkg(-1)min(-1)) and differences were evaluated by an independent sample t-test. Bland-Altman plots were performed to illustrate the agreement between methods. The women's HRR values at VT1 were similar to 40% HRR in both VO2max groups. At VT2 both VO2max groups exhibited negative differences (P<0.01) for the predicted 84%HRR intensity (-14.46% in the lower VO2max group and -16.32% in the higher VO2max group). An upper limit of 84% overestimates the %HRR value for the second ventilatory threshold, suggesting that the cardiorespiratory target zone for this population should be lower and narrower (40-70%HRR).

Rapšu eļļas degvielas patēriņa un izmešu emisijas pētījumi, iesmidzinot ūdens–bioetanola maisījumu motora ieplūdes sistēmā / The Rapeseed Oil Fuel Consumption and Exhaust Emissions Research Injecting a Water–Bioethanol Blend in the Engine Intake System

AbstractA research on the NOxreduction potential in diesel engine emissions injecting a 50% water-bioethanol blend in the engine intake system was carried out. Experiments were conducted on the test bench equipped with an Opel 16 DA four-cylinder 1.6-litre diesel engine and a two-tank system to run the engine on rapeseed oil. Toxic emissions were estimated using AVL SESAM FTIR multicomponent exhaust gas analytical system; the fuel consumption was measured using Kern 440-49A electronic weighing system. Three repetitions at the 1500 min-1and 2500 min-1engine crankshaft rotational speeds were performed; duration of each repetition - 120 seconds. Investigation results showed that such approach can reduce the nitrogen oxide content in exhaust gases by 32%, without significantly affecting other toxic emissions, at the same time reducing fuel consumption by 16-21%. Both rapeseed oil fuel and additive WE50 were derived from renewable resources, which plays an important role in elimination of climate changes.

Missing a trick

Karsten Brink Floor, FLSmidth Inc. Automation Division/FLSmidth Airloq A/S, Denmark, argues that, despite their low use, kiln inlet gas analysis systems are vital to optimising cement production and outlines the company's new Kinloq system.