Measurement Of Gas Volume Research Articles

Correlation of CT measurements of total body gas volume and hounsfield units with post-mortem interval

Accurate estimation of the post-mortem interval (PMI) may be a matter of crucial importance in forensic investigations.A preliminary investigation to assess whether longitudinal changes in organ Hounsfield units (HU) and total body gas volume (TBGV), as measured from serial PMCT scans, correlate with postmortem interval (PMI).: Eight euthanised lambs each had five whole body CT scans performed over seven days and measurements were taken from the brain, heart, lungs, liver, kidneys and spleen. HU tissue density was measured directly from the PMCT images, while TBGV was calculated using ImageJ software. A random effect model was fitted with the subject fitted as a random intercept. Ethical and Animal Welfare approval was obtained. : The average increase in TBGV was 422 ml/Kg with a change of 77 ml/Kg per day. For each additional post-mortem day, the HU of the brain, heart, lung, liver and spleen decreased by per day since death, while HU for the kidneys increased by day since death. Expect for the kidney where it increased, there was clear and progressive decrease in tissue densities and for all organs there was an increase in TBGV over time. However, the overlap in values between cases indicates that more work is required before either HU or TBGV can be developed as non-invasive methods to reliably determine time of death in humans.

Molybdenum oxide catalyst for wastewater treatment studied by faradaic efficiency

The measurements of gas volumes evolved during electrochemical wastewater treatment provide the information on the process faradaic efficiency. This work demonstrates how it enables identification of the water oxidation pathway (2 or 4 electron) in flow electrolysis process through the application of the formulae suggested in the study. This way, the real wastewater oxidation strength, i.e. production of hydrogen peroxide can be determined based on calculations. These provide more accurate results than direct measurements of accumulated hydrogen peroxide concentration after the electrolysis process, as its instability may lead to its immediate decomposition and false results. As an example provided in the paper, the application of MoO3 as a catalyst in the carbon composite electrode indicates almost no hydrogen peroxide detected after the process, whereas its oxidative properties owing to production of hydroxyradicals demonstrate complete decomposition of wastewater analogue (methylene blue). The calculations point to high production of H2O2. Using pure carbon material without the catalyst in the same experiment, decomposition occurs at much lower rate. The possible mechanisms behind the processes are discussed. The approach presented in the work can aid to efficient development of catalysts towards two-electron water oxidation.

Design improving the quality of natural gas volume measurement with G1.6÷G25 meters by optimizing their metrological verification

Design improving the quality of natural gas volume measurement with G1.6÷G25 meters by optimizing their metrological verification

AUTOMATED NATURAL GAS VOLUME MEASUREMENT SYSTEM

One of the main problems in the gas supply industry remains the insufficient accuracy in determining the volumes of consumed gas. On the one hand, this is due to the use of faulty or outdated measuring equipment in metering stations, and on the other hand, the operating conditions of metering stations do not always meet the requirements of technical documentation. In particular, the absence of automated data collection and processing systems from metering stations complicates, and sometimes prevents, the monitoring of actual natural gas consumption. Therefore, the task of creating automated gas volume measurement complexes remains relevant.
 The aim of this work is to substantiate the structure and elements of such a complex.
 The article presents a generalized structure of a gas metering station based on an automated measurement complex. One of the key elements of complex, ensuring the quality and accuracy of measurements, is the gas flow converter under working conditions.
 The authors have analyzed the methods of gas flow measurement that have gained the widest popularity in measurement practice and the possibilities of using devices based on them, considering the peculiarities of the operational use of the complex. In turn, the operating conditions are determined by internal technological, external mechanical, and design factors.
 A separate issue in the creation of an automated complex is the application of interfaces for data exchange with other systems or remote data transmission. The paper formulates requirements for the functionality of the electronic computing unit and its software, which, in addition to polling, registration, indication, and calculations, include self-diagnostics.
 The application of the complex will significantly improve the quality of natural gas metering and contribute to increased resource utilization efficiency, gas consumption forecasting, loss reduction, prevention of possible emergency situations, and more, based on the collection, processing, and analysis of measurement data.

An effective method for measuring the stiffness of a sealed vessel that can be applied to RPC gas volumes

A known volume of air is injected into or aspirated from a sealed vessel. In the ideal gas approximation, the corresponding vessel deformation is measurable. The linear correlation between pressure and deformation in the measurements carried out demonstrates the vessel’s elastic response. Measurements of several RPC gas volumes are reported. Different expansion and compression slopes of pressure vs volume plots, highlight a structure problem, for example, unglued spacers. Defective stiffness values of the electrode materials are also highlighted by anomalous slope values.

Menstrual Cycle Variation in MRI-Based Quantification of Intraluminal Gas in Women With and Without Dysmenorrhea.

Women frequently report increased bloating, flatulence, and pain during the perimenstrual period. However, it is unknown whether women have more intraluminal gas during menses. To evaluate whether pain-free women or women with dysmenorrhea have different amounts of intraluminal bowel gas during the menses, we utilized magnetic resonance imaging (MRI) to determine colonic gas volumes throughout the menstrual cycle. To avoid dietary influence, the participants were instructed to avoid gas-producing foods before their scheduled MRI. We verified the measurement repeatability across the reviewers and obtained an intraclass correlation coefficient of 0.92. There were no significant differences in intraluminal gas volume between menses and non-menses scans (p = 0.679). Even among the women with dysmenorrhea, there was no significant difference in the intraluminal gas volume between menses and non-menses (p = 0.753). During menstruation, the participants with dysmenorrhea had less intraluminal gas than participants without dysmenorrhea (p = 0.044). However, the correlation between the bowel gas volume and the pain symptoms were not significant (p > 0.05). Although increased bowel symptoms and bloating are reported in the women with dysmenorrhea during menses, our results do not support the hypothesis that increased intraluminal gas is a contributing factor. Although dietary treatment has been shown in other studies to improve menstrual pain, the mechanism responsible for abdominal symptoms requires further investigation. Our findings demonstrate that the intraluminal bowel gas volume measurements are feasible and are unaffected by menses under a controlled diet. The method described might prove helpful in future mechanistic studies in clarifying the role of intraluminal bowel gas in other conditions.

Comparison of two gas volume measurement systems by evaluating biochemical methane potential

AbstractThe objective of this study is to compare and analyze the efficiency of an automated measurement system for biogas flow with a control performed by a programmable logic controller (PLC) called the SAMB compared to commercial equipment widely disseminated for this purpose, the automatic methane potential test system (AMPTS II). The objective is to identify the accuracy in gas flow analysis of the two systems. The experiments were conducted in triplicate at a constant temperature of 37°C in anaerobic reactors. Two synthetic substrates and two natural substrates combined with a microbial inoculum were used. Considering the different ways the two systems capture data, the results show that all samples differed statistically between them (p < 0.01) in each system. However, in relation to paired substrates between systems, the samples did not present statistically significant differences (p > 0.05). Thus, with the advancement and globalization of knowledge, it is necessary to develop systems capable of generating standardized, precise, and accurate data. In this context, the systems evaluated here present different forms of methane measurement but the results have no significant statistical differences.

Pulmonary Function Testing in the Coronavirus Disease Era: Lessons and Opportunities.

Pulmonary Function Testing in the Coronavirus Disease Era: Lessons and Opportunities.

Original Article: Clinical Research.

Aim:In this study, we aimed to investigate the possible role of endotrophin, a profibrotic byproduct of collagen VI, in the complex process of fibrosis development in the disease group with pulmonary fibrosis among interstitial lung diseases.Material and Method:When the patients’ participation in the study were completed, smoking or alcohol drinking conditions, and family history were recorded. Their weights and heights were recorded and body mass index (BMI) was calculated. In every patient, Spirometry with bronchodilator testing, determination of single-breath DLCO, and plethysmographic measurement of thoracic gas volume and airway resistance were performed. Blood samples were obtained for the inflammation markers such as sedimentation rate, C-reactive protein (CRP), complete blood count, liver and renal function tests, and lactate dehydrogenase levels. Serum endotrophin levels were measured in all patients.Results:Thirty-five patients with interstitial lung disease who were having pulmonary fibrosis, 35 patients with interstitial lung disease without pulmonary fibrosis, and 20 control patients without any signs or symptoms of interstitial lung disease were included in the study. Age distribution was similar between groups. The fibrotic ILD group was more commonly smoker or ex-smoker compared with the non-fibrotic ILD patients or control cases. Fibrotic ILD patients were leaner, having significantly decreased total lung capacity, diffusion capacity, and higher LDH levels. In the comparison of the 3 study groups regarding the endotrophin levels, there was a significant difference between groups. The fibrotic and non-fibrotic patient groups were compared for the Endotrophin levels and the difference was also significant. However, there was not any significant difference regarding the endotrophin levels between control cases and non-fibrotic ILD patients. Smoked cigarette pocket x year showed a significant positive correlation and DLCO % and KCO % showed a significant negative correlation with the endotrophin levels.Conclusion:Serum endotrophin levels significantly increase in fibrotic ILD patients compared with the non-fibrotic ILD patients and control cases. Endotrophin may be suggested as a diagnostic marker in fibrotic interstitial lung diseases.

State Primary Standard of Gas Volume and Flow Rate Units for the Pressure Range of 1 MPa to 5 MPa (PVTt-15)

For the first time in Ukraine a primary measurement standard of gas volume and flow rate units in a pressure range of 1 MPa to 5 MPa has been created. The standard is based on realisation of the units by PVTt principle and units dissemination using critical Venturi nozzles. Gas passing through the nozzle during its calibration fills an evacuated collection tank located downstream the nozzle, and the respective time interval is measured. Mass flow rate is calculated by multiplying the volume of the collection tank by the gas density change and dividing by the tank filling time. Density values are determined by the equation of state and the measured initial and final pressure and temperature values. The structural and functional scheme of the measurement standard is shown in Figure 3.
 The standard consists of two units. The first unit is intended to realise, keep and transfer the units of gas volume and flow rate. The general view of the block is shown in Figure 4. The unit contains high pressure collection tank, precision water thermostat, vacuum pump, piston gas pressure gauge, flow switch, fine filter, a set of seven Venturi nozzles with diameters from 0.1 mm to 3.0 mm. The second unit is designed to form a stationary gas flow and provide a critical gas flow rate (at the speed of sound) at the nozzle throat. In the case of an elementary reversible adiabatic (isoentropic) process at a critical velocity, the mass flow rate of gas passing through the nozzle is maximally possible. The unit consists of equipment for reducing the pressure from 150 bar to 70 bar and from 70 bar to 10 bar, the heat exchanger and the instruments measuring the pressure and temperature of the gas flow. The created measurement standard will assure metrological traceability of the measurements of gas volume and volume flow rate at high pressures for the flow rate up to
 100 m3/h and calibration of the primary reference nozzles with a throat diameter from 0.1 mm to 3 mm.

Methodology and software for measuring the specific differences of the calculated volumes of natural gas

The most accurate measurement of natural gas volumes by domestic meters can be achieved only in case when the gas parameters (pressure, temperature) are maximally approximated to the standard conditions. Otherwise, it is necessary to perform additional measurements of these parameters, but most domestic gas meters do not include the measuring instruments to obtain these quantities; or to carry out approximate mathematical calculations, which from the point of view of metrology is unreliable.The purpose of the work is mathematical modeling of specific differences of the accounted volumes of natural gas and development of methods for their measurement.The methodology of measurement by indirect methods of changing the volumes of natural gas in gas supply systems of residential buildings with domestic gas meters is developed. The dependence is obtained for estimating the specific differences of natural gas volumes in domestic consumers by measuring the volume of gas by a household gas meter, the temperature parameters of the air in the room near the gas pipeline and the gas and air meter. The physical quantities of the ambient air parameters are identified, which are determined by the method of direct measurement, and based on the obtained results, a methodology for estimating the metrological characteristics of the indirect measurement of the specific differences of natural gas volumes is developed.The results obtained by theoretical development are confirmed by experimental studies on a certified calibration setup operating on natural gas.The results obtained can be the basis for reviewing the existing and developing new regulatory documents for determining the specific differences in natural gas volumes recorded by domestic gas meters. Prospects for further research are the development of the structure of the information measurement system and devices for the determination of the specific losses of natural gas in house systems of gas supply.

Theoretical and Experimental Gas Volume Quantification of Micro- and Nanobubble Ultrasound Contrast Agents.

The amount of gas in ultrasound contrast agents is related to their acoustic activity. Because of this relationship, gas volume has been used as a key variable in normalizing the in vitro and in vivo acoustic behavior of lipid shell-stabilized bubbles with different sizes and shell components. Despite its importance, bubble gas volume has typically only been theoretically calculated based on bubble size and concentration that is typically measured using the Coulter counter for microbubbles and nanoparticle tracking analysis (NTA) for nanoscale bubbles. However, while these methods have been validated for the analysis of liquid or solid particles, their application in bubble analysis has not been rigorously studied. We have previously shown that resonant mass measurement (RMM) may be a better-suited technique for sub-micron bubble analysis, as it can measure both buoyant and non-buoyant particle size and concentration. Here, we provide validation of RMM bubble analysis by using headspace gas chromatography/mass spectrometry (GC/MS) to experimentally measure the gas volume of the bubble samples. This measurement was then used as ground truth to test the accuracy of theoretical gas volume predictions based on RMM, NTA (for nanobubbles), and Coulter counter (for microbubbles) measurements. The results show that the headspace GC/MS gas volume measurements agreed well with the theoretical predictions for the RMM of nanobubbles but not NTA. For nanobubbles, the theoretical gas volume using RMM was 10% lower than the experimental GC/MS measurements; meanwhile, using NTA resulted in an 82% lower predicted gas volume. For microbubbles, the experimental gas volume from the GC/MS measurements was 27% lower compared to RMM and 72% less compared to the Coulter counter results. This study demonstrates that the gas volume of nanobubbles and microbubbles can be reliably measured using headspace GC/MS to validate bubble size measurement techniques. We also conclude that the accuracy of theoretical predictions is highly dependent on proper size and concentration measurements.

Volume and rate measurement of slowly generated gas bubbles

The use of an inverted burette arrangement that allowed volume and time-course tracking of bubble movement via camera imaging is shown here to improve on the classical inverted jar (or beaker) method for measuring gases generated in small volumes and at slow rates (below 1 mL/s). In tests involving discrete gas volume measurements delivered at 0.57 mL/s, comparison with pre-set air volume delivered by a syringe pump showed high correspondence, linearity, and repeatability. Tests with continuous gas flows at 0.2, 0.32 and 0.57 mL/s revealed average bubble count versus volume trends that displayed high linearity to indicate that the bubble volumes (at any flowrate) were constant. The average bubble count versus time also showed linear trends and repeatability indicating that the time intervals between the appearance of any two bubbles (at a particular flowrate) were uniform. The analytical and simulated results helped to explain why bubble size determination by high speed camera recording for measuring gas volume and flowrate is fraught with inherent problems. An analysis using light ray tracing showed that flowrate determination using such an approach would necessitate complicated image correction when two cameras are used for simultaneous recording due to distortion effects resulting from refraction. A virtual gate approach involving the binarization of images recorded with a standard camera is shown to be more feasible in establishing the flowrate using bubble counting or finding the time interval between bubbles.

Restriction of lung volumes but normal function of pulmonary tissue in mulibrey nanism

Mulibrey nanism (MUL) is a rare growth restriction disorder with multiple organ manifestations caused by genetic defects affecting the TRIM37 protein. A perimyocardial heart disease is the most serious manifestation. Many MUL children appear to suffer from airway obstruction related to infection or exercise, prompting use of inhaled therapies. Asthma medication is continued up to adolescence or even to adulthood due to persisting of symptoms. The pulmonary pathophysiology has previously not been evaluated in any MUL cohort. Thirty three finnish MUL patients (median age 20 years) were investigated with several lung function tests: spirometry with bronchodilatation test, single-breath diffusing capacity for carbon monoxide, single-breath lung volume measurements with helium dilution, and thoracic gas volume, airway resistance and specific conductance measurements with a body plethysmograph. As MUL typically affects body proportions, all variables were compared with reference values and with predicted values calculated from sitting height. Total lung capacity and forced vital capacity were markedly reduced (total lung capacity [TLC] and forced vital capacity [FVC], P < .001, 51%-63% of predicted) and also forced expiratory volume in the first second was reduced (FEV1; P < .001, 47%-57%). No signs of airway obstruction was seen (normal FEV1/FVC and specific airway conductance SGaw). Diffusing capacity (DLCO) was decreased (P < .001, 60%-67%) but when related to alveolar volume it was increased (DLCO/VA, P < .001, 130%-148%). Bronchodilatation suggesting active asthma (FEV1 change ≥12% and ≥​​200 mL) was found only in one patient. MUL patients typically have volume restriction of the lungs, but function of the pulmonary tissue remains intact. Evidence of asthma in lung function testing at adult age is rare.

Pengaruh Penambahan Urea pada Mediad dan Pemanasan terhadap Produksi Biogas

Biogas is one of the energy sources originating from livestock waste, besides being environmentally friendly (renewable energy), it can also be used for sustainable energy. Biogas is a mixture of gases resulting from an anaerobic fermentation process from livestock manure (cow). The purpose of this study was to determine the effect of adding various urea concentrations and heating in deep biogas production. This study applied a completely randomized design (RAL) with two treatment factors: heating (heating and without heating) and urea concentration (2%, 4%, 6%, 8%). Observations carried out in the form of measuring the temperature of biogas media, gas volume, CO2, the volume of methane gas, and the time of biogas formation. Variant analysis showed that the heating interaction and urea concentration showed a significant effect (P &lt;0.05) on the measurement of biogas media temperature, gas volume, CO2, methane volume, and biogas formation time. The results showed that the combination of heating treatment with 8% urea concentration was the best treatment in producing biogas with the characteristics of gas volume of 16.67 ml, CO2 content of 0.08%, methane volume of 15.49 ml, with the time of biogas formation which is on the day 10.&#x0D;

COMBINATION OF THE ISOCHORIC METHOD AND THE EXPANSION METHOD TO DETERMINE DENSITIES OF HYDROGEN AT TEMPERATURES UP TO 500°C

Utilization of hydrogen as an alternative fuel is promising because it is environmentally friendly. Hydrogen system design requires accurate hydrogen densities. The density of hydrogen is determined based on experimental data. For gases that have a low density such as hydrogen, the effective measurement method is required. An apparatus has been designed to measure PVT properties of hydrogen at pressures up to 1 MPa and temperatures up to 500ºC. The apparatus uses a combination of isochoric and expansion methods. The method doesn’t need a measurement of pressures and temperatures along the isochoric line as required usually in the isochoric conventional method. Moreover, it doesn't need direct measurements of gas mass and gas volume. The volume was determined by measuring nitrogen at a pressure of 0.5 MPa and at temperatures up to 500ºC and by using Span’s equation of state. Measurements of hydrogen have been performed at a pressure up to 0.7 MPa and temperatures up to 498.217ºC. Densities of hydrogen obtained from the present measurement are compared with that obtained from calculation of Leachman's equation of state. Maximum deviation is 1.42% at a temperature of 498.217ºC and at a pressure of 0.2947 MPa and minimum deviation is 0.11% at temperature and pressure of 399.461ºC and 0.6981 MPa respectively.

Precise Measurement of Gas Volumes by Means of Low-Offset MEMS Flow Sensors with μL/min Resolution.

Experiments devoted to evaluate the performance of a MEMS thermal flow sensor in measuring gas volumes are described. The sensor is a single-chip platform, including several sensing structures and a low-offset, low-noise readout interface. A recently proposed offset compensation approach is implemented obtaining low temperature drift and excellent long time stability. The sensor is fabricated by applying a simple micromachining procedure to a chip produced using the BCD6s process of STMicroelectronics. Application of a gas conveyor allowed inclusion of the sensing structure into a channel of sub-millimeter cross-section. The results of measurements performed by making controlled air volumes pass through the sensor channel in both directions at rates from 0.1 to 5 mL/min are described.

Investigations into the identification and control of outburst risk in Australian underground coal mines

Australian coal mines currently use gas content to assess outburst risk. The gas content threshold values for each mine are indirectly determined from measurement of gas volume liberated from 150g coal samples during Q3 residual gas content testing. It has been more than twenty years since this method, known as desorption rate index (DRI), was presented to the Australian coal industry, and in that time, there have been significant changes in mining conditions and the outburst threshold limits used at the benchmark Bulli seam mines. NSW Regulations list matters to be considered in developing control measures to manage the risk of gas outburst, and specifies that gas content, or DRI method, is used as the basis for determining outburst control zone. Whilst Queensland Regulations state that a coal or rock outburst is a high potential incident, there is no guidance provided to assist mine operators to define outburst prone conditions. A research project is planned at UOW to investigate the application of the DRI method and other potentially significant factors, such as gas pressure, coal toughness and permeability, which can be utilised by mine operators to assess outburst risk and determine appropriate outburst threshold limits and controls.

Validity of Prediction of Thoracic Gas Volume and Body Composition Using Air Displacement Plethysmography in People Living with HIV in Southwest Ethiopia

Background: Body composition assessment has become increasingly popular in clinical and research areas. But any body composition measurement technique that is used in both clinical and research settings should be reliable and valid. Objectives: Our first aim was to compare predicted thoracic gas volume (Vtgpred) with measured thoracic gas volume (Vtgmeas) using the BOD POD in people living with HIV/AIDS (PLWHA) in Southwest Ethiopia. The second aim was to determine the effect of thoracic gas volume (Vtg) measurement ways on estimation of body fat (BF) using the BOD POD in PLWHA in Southwest Ethiopia. Method: Cross-sectional study was conducted on 68 PLWHA who had follow up at Jimma University Specialized Hospital (JUSH). Subjects were collected using convenience sampling technique. Agreement between the methods was tested using paired t-test, Pearson’s correlation, linear regression, and Bland-Altman plot. Result: Much percent of study subjects were malnourished (60.3%). Vtg and percent body fat (%BF) did not differ significantly (p>0.05) between the two modes of assessment (predicted and measured). Strong correlation was observed between Vtgpred and Vtgmeas (r=0.82, p<0.001). Correlation between predicted %BF (%BFpred) and measured %BF (%BFmeas) was also strong(r=0.92, p<0.001). The regression of Vtgmeas(Y) against Vtgpred (X) (Y=- 0.369+1.140X, R2=0.68, SEE=0.015) did not significantly deviated from the line of identity. Similarly, the regression of %BFmeas (Y) against %BFpred (X=1·70+0.94X, R2=0·96) did not significantly deviated from the line of identity. Bland- Altman plot of the differences against the mean of Vtgpred and Vtgmeas and the differences against the mean of %BFpred and %BFmeas showed no systematic differences. Conclusion: The BOD-POD is a reliable technique to predict Vtg and body composition in PLWHA in Southwest Ethiopia. Therefore, researchers and clinicians can confidently use the predicted Vtg and body fat in place of the measured ones in PLWHA in Southwest Ethiopia.

Rectal Gas Volume Measured by Computerized Tomography Identifies Evacuation Disorders in Patients With Constipation.

Approximately one third of patients who present to gastroenterology care with constipation have rectal evacuation disorders. We aimed to compare rectal gas volume, measured by computerized tomography (CT), in constipated patients with and without rectal evacuation disorders. In a retrospective study, we collected data from 1553 patients with constipation, evaluated over 20 years. We analyzed data from 141 patients evaluated by anorectal manometry, balloon expulsion tests, and colon transit tests, collecting records of abdominal and pelvic CT examinations. Patients were classified into 3 subgroups: those with rectal evacuation disorders, slow-transit constipation, or normal-transit constipation. Two observers used standard CT software to identify variable regions of interest on each cross-sectional CT image that contained rectum and measured areas of gas in each slice; they then summated entire volumes of rectal gas. For the 3 groups, we compared rectal gas volume, maximal rectal gas transaxial area (measured by CT), and area of rectal gas (vertical) on the 2-dimensional abdominal film (scout) using the Kruskal-Wallis test. The intraclass correlation coefficient between 2 observers' measurements of rectal gas volume was 0.99 (P < .001). There were overall group differences in rectal gas volume and the maximal rectal gas transaxial area (both P < .001). The median rectal gas volume was higher in patients with rectal evacuation disorders (13.84 cm3) than in patients with slow-transit (2.51 cm3) or normal-transit constipation (1.33 cm3, both P < .05). Similarly, the area of rectal gas, which correlated with the maximal rectal gas transaxial area (Spearman correlation coefficient, 0.7; P< .001), showed overall 3-group differences (P= .033), with greater areas of rectal gas on the abdominal scout film in patients with rectal evacuation disorders than in those with normal-transit constipation. In an analysis of patients with constipation, we found rectal gas volume, determined by abdominal CT imaging, to be greater in patients with than without rectal evacuation disorders.