Gas Profiles Research Articles

Comprehensive Molecular Profiling and Clinicopathological Characteristics of Gastric-Type Mucinous Carcinoma of the Uterine Cervix in Japanese Women.

Gastric-type mucinous carcinoma (GAS) of the uterine cervix is the most common adenocarcinoma that develops independently of human papillomavirus infection; it is typically diagnosed at an advanced stage and has a poorer prognosis than usual-type endocervical adenocarcinoma. Few studies have examined the molecular profile of GAS, but genetic alterations in TP53 and STK11 have been repeatedly reported. We analyzed the clinicopathological characteristics and molecular profile of GAS. Fresh-frozen tissue specimens and formalin-fixed paraffin-embedded (FFPE) tissues from 13 patients with GAS treated between January 2000 and December 2020 were analyzed. We performed next-generation sequencing on eight fresh-frozen GAS specimens using the Cancer Hotspot Panel v2 (cases 1-8) and the FoundationOne companion diagnostic (F1CDx) assay on six FFPE samples (cases 8-13). Seventy-four genomic alterations were identified in 42 genes. In order of frequency, TP53, ATRX, CDKN2A, KRAS, APC, and STK11 were altered in at least three cases. Targetable genomic alterations were identified in all six patients' specimens analyzed using the F1CDx assay. GAS harbors various genomic alterations associated with sustained activation of signaling pathways or cell cycle regulation in addition to abnormalities in TP53, and precision medicine based on molecular profiling will be necessary to overcome GAS.

CFD Analysis of Exhaust System of a Formula Racing Vehicle

This study investigates about the designing and Computational Fluid Dynamics (CFD) analysis of the exhaust system of a formula student vehicle. Based on FSAE rules KTM Duke 390 engine is used and the noise level is to keep below 110 dB. The main aim of the design is to have a smooth flow exhaust gases without restriction to increase engine efficiency and to keep minimal backpressure. An absorptive type of muffler is finalized to attenuate the sound levels. Based on three different equations, exhaust runner dimensions are calculated and CFD analysis is performed to choose the optimum runner dimensions. Using ASHRAE guidelines muffler dimensions range is calculated. Using Ricardo software based on effective volumetric efficiency analysis, volume of muffler that fits in ASHRAE dimension range was finalized. Both runner and muffler are analyzed and CFD analysis was carried out which resulted in streamline velocity profile of the exhaust gas and acceptable values of pressure, velocity and velocity streamline was found. CFD analysis of the full exhaust system was carried out to understand the flow characteristics of exhaust gases.

The hot gas distribution, X-ray luminosity, and baryon budget in the L-Galaxies semi-analytic model of galaxy formation

ABSTRACT Hot ionized gas is important in the baryon cycle of galaxies and contributes the majority of their ‘missing baryons’. Until now, most semi-analytic models of galaxy formation have paid little attention to hot gaseous haloes and their X-ray emission. In this paper, we adopt the one-dimensional model from Sharma et al. instead of the isothermal sphere to describe the radial distribution of hot gas in the L-Galaxies semi-analytic model. The hot gas halo can be divided into two parts according to the ratio of the local thermal instability time-scale and the free-fall time-scale: a cool core with tTI/tff = 10 and a stable outer halo with tTI/tff > 10. We update the prescriptions of cooling, feedback, and stripping based on the new hot gas profiles, and then reproduce several X-ray observational results like the radial profiles of hot gas density, and the scaling relations of X-ray luminosity and temperature. We find: (1) Consistent with observations, flatter density profiles in halo centers produce lower X-ray emission than an isothermal sphere; (2) Cool core regions prone to precipitation have higher gas temperature than the virial temperature, and a larger TX/T200 ratio in smaller haloes leads to a steeper slope in the LX–TX relation; (3) The ionized gas in the unbounded reservoir and low-temperature intergalactic gas in low-mass haloes could be the main components of the halo ‘missing baryons’. Our model outputs can predict the observations of hot gas in the nearby universe and produce mock surveys of baryons probed by future X-ray telescopes.

Integrated characterization of wormhole growth and propagation dynamics in CHOPS reservoirs with a unified and consistent ensemble-based framework

In this paper, a unified and consistent ensemble-based framework has been established for the first time to simulate the wormhole growth and propagation dynamics in a cold heavy oil production with sand (CHOPS) reservoir. More specifically, a recently modified pressure-gradient-based (PGB) sand failure criterion has been integrated into a reservoir simulator via a damped-iterative-ensemble-Kalman-filter (damped-IEnKF) framework in which foamy oil mechanisms are considered to quantify the changes in porosity and permeability in a CHOPS reservoir conditioned to its oil, water, gas, and sand production profiles. Subsequently, such an integrated model was applied to a single-well case from the Cold Lake heavy oil deposit and then a five-well case from the Lloydminster heavy oil area by alternatively combining the skin factor concept to reduce the computational expenses without compromising the simulation accuracy. The composite impact of sand failure and slurry flow on the multiphase flow behaviour was examined with different sets of relative permeability curves at each distinct production stage. By conditioning the simulated model to the observed production in the five-well case, skin factors have been alternatively assigned to each well to quantify the near wellbore damage on the initiation and development of wormhole networks. Not only have the production profiles been well matched, but also satisfactory agreements between the simulation outcomes and the in-situ observations have been obtained for both cases. It is found that the saturations of residual oil and connate water can be both significantly reduced by the sand failure mechanism, while the overall relative permeability can be reduced by the presence of slurry flow. A high pressure difference in the vicinity of a wellbore was formed owing to a large skin factor with respect to the restricted wellbore flow rate, significantly aggravating the sand failure. To better reproduce the production profiles in the five-well case, different skin factors were used for each well. In practice, the wormhole growth and propagation dynamics can be accurately and efficiently evaluated and forecasted with such an integrated model in a CHOPS reservoir, demonstrating its practicality and reliability in simulating the wormhole network dynamics and evaluating the performance of subsequent enhanced oil recovery (EOR) processes within a unified, efficient, and consistent framework.

Preflight Evaluation of the Environmental Trace Gases Monitoring Instrument with Nadir and Limb Modes (EMI-NL) Based on Measurements of Standard NO2 Sample Gas

Hyperspectral observations are used to retrieve high-resolution horizontal distribution and vertical profiles of trace gases (O3, NO2, HCHO, and SO2), thereby playing a vital role in monitoring the spatio-temporal distribution and transportation of atmospheric pollutants. These observations reflect air quality changes on global and regional scales, including China, thereby elucidating the impacts of anthropogenic and natural emissions on atmospheric composition and global climate change. The DaQi 02 (DQ02) satellite carries the Environmental Trace Gases Monitoring Instrument with Nadir and Limb modes (EMI-NL) onboard, which will simultaneously perform nadir and limb measurements of high-resolution ultraviolet and visible solar scattered light in the nadir and limb directions. Combined with the absorption of different trace gases in this wavelength band, this information can provide high-resolution horizontal and vertical distributions of trace gases. We examined the spectral measuring ability and instrument characteristics of both modules of EMI-NL by measuring different light sources and concentrations of the NO2 sample gas. In the nadir module test, when the NO2 sample gas concentration was 198 ppm and 513 ppm with scattered sunlight as the light source, the average relative errors of spatial pixels were 4.02% and 3.64%, respectively. At the NO2 sample gas concentration of 198 ppm with the integrating sphere as the light source, the average relative error of spatial pixels was −2.26%. In the limb module test, when the NO2 sample gas concentration was 198 ppm and 1000 ppm with the tungsten halogen lamp as the light source, the average relative errors of spatial pixels were −3.07% and 8.32%, respectively. When the NO2 sample gas concentration was 198 ppm and 1000 ppm with the integrating sphere as the light source, the spatial pixel average errors were −3.5% and 8.06%, respectively. The retrieved NO2 slant column density between different spatial pixels exhibited notable inconsistency in both modules, which could be used to estimate the stripe of spatial dimension. These results confirm the ability of EMI-NL to provide accurate spaceborne monitoring of NO2 globally.

Evidence for powerful winds and the associated reverse shock as the origin of the Fermi bubbles

ABSTRACT The Fermi bubbles are large gamma-ray-emitting structures. They are symmetric about the Galactic Centre (GC), and their creation is therefore attributed to intensive energy injection at the GC. In this study, we focus on the non-equilibrium X-ray gas structures associated with the bubbles. We show that a combination of the density, temperature, and shock age profiles of the X-ray gas can be used to distinguish the energy-injection mechanisms. By comparing the results of numerical simulations with observations, we indicate that the bubbles were created by a fast wind from the GC because it generates a strong reverse shock and reproduces the observed temperature peak there. On the other hand, instantaneous energy injection at the GC cannot reproduce the temperature profile. The wind had a speed of ${\sim} 1000\rm \: km\: s^{-1}$, and blew for ∼107 yr. Because the mass flux of the wind is large, the entrainment of interstellar gas by wide-angle outflows from the black hole is required. Thus, the wind may be the same as active galactic nuclei outflows often observed in other galaxies and thought to regulate the growth of galaxies and their central black holes.

Gas Profiles Unravel Fractured and Compartmentalized Reservoirs

The profiles of gas in reservoirs of the Nene Oil Field in the Lower Congo Basin was modelled and evaluated for the objective of delineating the reservoir structure. The wells are NNM Well 6, NNM Well 301 and NNM Well 302. The C1 profiles show significant difference between wells 6 and 301 relative to well 302. The C1 profile for Well 302 unravels gas migrations from different compartments at the reservoir depth and mixes at a depth of 1.5KM. The observation also indicates the presence of a fracture that allow homogenization of the gases at that depth. The iC4/nC4 ratio for NNM Well 302 showed a profile for which the ratio is greater than 1.0 throughout the well section downdip. The observation portrays biodegradation throughout the well section generation from an immature source. The study shows that the NNM Well 6 reservoir is laterally compartmentalized from others, while all the well shoe some potential for vertical continuity of the wells

Retrieval of tropospheric ozone profiles using ground-based MAX-DOAS

In recent years, surface ozone concentrations have increased in many cities in China. Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) is a powerful technique for retrieving the profiles of tropospheric trace gases, such as NO2, SO2, and HCHO. However, since the difficulties in deducting the effects of stratospheric ozone, there are few studies on the retrieval of tropospheric ozone profiles using MAX-DOAS measurements. Here, we developed an accurate inversion method to retrieve tropospheric ozone concentrations during the PRIDE-GBA Campaign, wherein the ozone differential slant column densities (DSCDs) were retrieved in QDOAS software using the “time-interpolated zenith spectrum” as the reference spectrum. The tropospheric DSCDs (DSCDstrop) were then calculated by subtracting the simulated stratospheric DSCDs (DSCDsstr, simulated from the SCIATRAN model) from the DSCDs. Tropospheric ozone profiles were retrieved from the DSCDstrop using the optimal estimation method (OEM). The results showed that high values of tropospheric ozone were mainly distributed below 1 km, which is consistent with lidar measurements. In addition, the observed surface ozone concentrations were highly correlated with the in-situ measurements, with correlation coefficients (R) of 0.75 and 0.81, respectively. Combined with the retrieved NO2 and HCHO profiles using the MAX-DOAS measurements, we found that the planetary boundary layer ozone pollution of HeShan Observatory during the PRIDE-GBA Campaign are controlled by the NOx-limited regime. The results of this study indicate that the MAX-DOAS technique has the potential to retrieve tropospheric ozone profiles with high temporal and spatial resolution.

Evaluation of Three Marine Algae on Degradability, In Vitro Gas Production, and CH4 and CO2 Emissions by Ruminants

Livestock production systems are responsible for producing ~18% of the total anthropogenic greenhouse gas (GHG) emissions. Numerous alternatives, such as feed additives or supplements, have been proposed to meet these challenges. Marine algae have been proposed for gas reduction in ruminants; nevertheless, there are still very few experimental reports. Thus, the objective of the current study was to identify the volatile organic compounds (VOCs) in three marine algae—Kelp (Macrocystis pyrifera), Ulva (Ulva spp.), and Silk (Mazzaella spp.)—and to test their in vitro ruminal fermentation characteristics, gas profiles, and ability to mitigate biogas production. The evaluation of the VOCs in marine algae was performed using a flash gas chromatography electronic nose (FGC-E-Nose). The in vitro study was elaborated through in vitro incubation and gas production. The data obtained were analyzed using a completely randomized design. In total, forty-three volatile compounds were identified for Kelp algae, thirty-eight were identified for Ulva algae, and thirty-six were identified for Silk algae; the compounds were from different chemical families and included aromas, alcohols, aldehydes, phenolics, carboxylic acids, esters, and nutraceutical properties. Dry matter degradability was significantly (p < 0.05) affected by the algae type. The cumulative ruminal gas production was different (p < 0.05) between treatments. Kelp algae presented a major (V; p < 0.05) volume of gas produced compared to the other algae. Lag time (l; p < 0.05) was increased by Kelp alga; however, there were no differences (p>0.05) between the Silk and Ulva algae. The gas production rate was higher (s; p < 0.05) for Silk algae compared to the others. Ulva and Silk algae demonstrated a significant (p < 0.05) decrease in carbon dioxide emissions. Nevertheless, Kelp algae reduced the proportional methane (CH4) production (p < 0.05) after 48 h of incubation, with the lowest emission rate of 47.73%. In conclusion, algae have numerous bio compounds that provide some properties for use in ruminant diets as additives to reduce methane and carbon dioxide emissions.

USE OF QUIZEZ AS А SUMMATIVE ASSESSMENT IN TEACHING STUDENTS OF AN OIL AND GAS PROFILE

At the moment there is an increasing literary evidence for the design of feedback in higher education. The role of assessing the students’ knowledge is an essential part in teaching. Students are often dissatisfied with standard models of giving feedback and their perceptions often do not align with that of teachers who feel that students may undervalue the feedback. Standard feedback tends to give limited information that focuses on the assessment product and does not engage students in learning processes. This article gives a brief outline of using summative assessment in teaching the oil and gas profile students. Actually the research is based on the idea that modern pedagogical technologies implemented nowadays are more effective and motivational than the previous methods of teaching. This research investigated the validity of using the quizzes as a form of summative assessment, instead taking an exam or questionnaires. The participants’ level of knowledge of English, in which this research was conducted, was intermediate at the University specialized in oil and gas profile, where greater demands are imposed on developing vocabulary skills by the recommended curriculum. The results of this research revealed that the role of assessment is indispensable and it has an ability to motivate students to learn English. The results of this research will also be used as a basis upon which specific suggestions for the practical implementation of assessment in the everyday classroom can be made.

Numerical and experimental investigation of gas–gas diffusion and convection

Gas-to-gas diffusion and convection phenomena exist in a wide range of applications, including industrial and scientific processes, food production and storage, and breathing gases. To analyze gas–gas mixing phenomena, a numerical model based on open-source tool libraries was developed and validated; an experimental model was built up and repeated physical tests were performed. Comparative mixing gas–gas profiles and O2 concentration time histories were presented to analyze gas–gas phenomena and to validate the developed numerical solver. Practically, relevant assessments of the gas-to-gas diffusion and convection process demonstrated that (1) obstacles accelerated gas–gas diffusion and convection, (2) diffusion and convection stabilized after a certain time period, and (3) stronger diffusion and convection occurred during the initial stages of the gas-to-gas contact.

Modeling analysis of the temperature profile and trapped annular pressure induced by thermal-expanded liquid in a deep gas well

The trapped annular pressure (TAP) caused by thermal expansion is one of the serious challenges for the safe production of a deep gas well. Therefore, this article proposes a model to calculate the temperature profile of the deep gas well based on the heat transfer process and the gas properties. With the help of the temperature model, the TAP in the tubing–casing annulus is analyzed according to the annular fluid distribution and the volume consistence law. The results indicate that the temperature inside the tubing string decreases faster under higher bottom hole pressure. When the tubing–casing annulus is totally filled with the annular protection liquid, the TAP continues increasing with the production rate. Considering the high production rate, the TAP is inevitable and high enough to damage the integrity of the deep gas well. The nitrogen gas mitigates the TAP by reducing the annular liquid volume and providing the extra space to accommodate the thermal-expanded annular liquid. A good mitigation performance can be achieved no matter how large the production rate is. The mitigation performance can be divided into the fast-decreasing stage, the efficient control stage, and the stable stage. These three stages occur as the nitrogen gas column length increases. The compression of the nitrogen gas volume plays a major role in the fast decrease stage while the reduction of the annular liquid plays a major role in the stable stage. For the best cost-effectiveness, the nitrogen gas column is recommended in the efficient control stage and should not exceed 15%.

An exploration of the properties of cluster profiles for the thermal and kinetic Sunyaev–Zel’dovich effects

ABSTRACT With the advent of high-resolution, low-noise CMB measurements, the ability to extract cosmological information from thermal Sunyaev–Zel’dovich effect and kinetic Sunyaev–Zel’dovich effect will be limited not by statistical uncertainties but rather by systematic and theoretical uncertainties. The theoretical uncertainty is driven by the lack of knowledge about the electron pressure and density. Thus, we explore the electron pressure and density distributions in the IllustrisTNG hydrodynamical simulations, and we demonstrate that the cluster properties exhibit a strong dependence on the halo concentration – providing some of the first evidence of cluster assembly bias in the electron pressure and density. Further, our work shows evidence for a broken power-law mass dependence, with lower pressure in lower mass haloes than previous work and a strong evolution with mass of the radial correlations in the electron density and pressure. Both of these effects highlight the differing impact of active galactic nuclei and supernova feedback on the gas in galaxy groups compared to massive clusters. We verified that we see qualitatively similar features in the SIMBA hydrodynamical simulations, suggesting these effects could be generic features. Finally, we provide a parametric formula for the electron pressure and density profile as a function of dark matter halo mass, halo concentration, and redshift. Despite our extensions, the best-fitting formulae are not able to fully capture the features seen in certain mass, radius, and redshift regimes, thereby highlighting the challenges of precision modelling gas profiles.

Electromigration of Au on Ge(111): Adatom and island dynamics

We have observed the motion of two-dimensional phases of Au on Ge(111) under an electric bias by in operando low energy electron microscopy. Electromigration of Au results in a complex dynamics that depends on the nature of the involved mobile phases: two-dimensional adatom gas or two-dimensional islands. We show that the Au adatoms move at the surface in the direction opposite to the electric current. The wind force induced by the electron flow is measured: the effective valence of Au (${Z}^{*}=\ensuremath{-}82\ifmmode\pm\else\textpm\fi{}15$) is directly deduced from the coverage profile of a Au adatom gas spatially retained by a strong Erlich-Schwoebel barrier at a downhill step edge. The velocity of two-dimensional Au islands versus island size reveals a mass transport by terrace diffusion inside the islands. The energy barrier for diffusion above 820 K is $1.16\ifmmode\pm\else\textpm\fi{}0.08$ eV and it strongly increases up to $3.1\ifmmode\pm\else\textpm\fi{}0.6$ eV below. We attribute this change of regime to a modification of diffusing species from single Au atoms at high temperature to Au clusters at low temperature. The strong shape fluctuations of the 2D islands is consistent with a nearly vanishing line tension of $1.2\ifmmode\pm\else\textpm\fi{}0.4$ meV/nm at 800 K.

The synergy of Fe(III) and NO2- drives the anaerobic oxidation of methane.

The anaerobic oxidation of methane (AOM) driven by NO2- or Fe(III) alone was limited by slow electron delivery and ineffective enrichment of microbes. The flexible coupling between Fe(III) and NO2- potentially cooperated to accelerate AOM. One negative control was fed CH4 and NO2-, and four treatment reactors were supplemented with CH4, NO2- and ferric citrate (FC)/ferric chloride (FCH)/ chelate iron (FCI)/ferric hydroxide (FH) and were anaerobically operated for 1200 days to verify the synergy and promicrobial roles of Fe(III) and NO2- in improving AOM. The changes in gas and ion profiles were observed in the reactors, and microbial development was studied using 16S rRNA gene sequencing with the Illumina platform. The results indicated that the combined Fe(III) and NO2- treatment improved AOM, and their synergy followed the order of FC > FCI > FCH > FH. The biochemical reaction of Fe3+ with NO2- and its secondary process accelerated electron transfer to microbial cells and subsequently enhanced AOM in the reactors. The total organic carbon (TOC) content, NH4+ content, NO3- content, and pH value altered the dominant bacteria the most in the FC reactor, FCI, FCH, and FH groups, respectively. Several dominant bacterial species were enriched, whereas only two archaea were highly concentrated in the FC and FCI groups. Only bacteria were detected in the FCH group, and archaea contributed substantially to the FH group. These findings contribute to an improved understanding of the interactions among nitrogen, iron and CH4 that are paramount to accelerating the process of AOM for engineering applications.

In Vitro Infant Fecal Fermentation Characteristics of Human Milk Oligosaccharides Were Controlled by Initial Microbiota Composition More than Chemical Structure.

Human milk oligosaccharides (HMOs), multifunctional glycans naturally present in human milk, are known to contribute to the infant's microbiota and immune system development. However, the molecular specificity of HMOs on microbiota and associated fermentation is not yet fully understood, and is important for the development of infant formula optimum functionality. In vitro fermentation is carried out on structurally different HMOs with infant fecal inocula dominated by Bifidobacterium longum, Bifidobacterium breve, and Bacteroides. The gas, metabolite (SCFA, lactate, and succinate) profiles, and microbiota responses differ between individual microbiota inocula patterns regardless of HMO structure. In terms of HMO pairs with same sugar composition but different glycosidic bonds, gas and metabolite profiles are similar with the B. longum- and B. breve-dominated inocula. However, large individual variations are observed with the Bacteroides-dominated inocula. The microbial communities at the end of fermentation are closely related to the initial microbiota composition. The findings demonstrate that short-term in vitro fermentation outcomes largely depend on the initial gut microbiota composition more than the impact of HMO molecular specificity. These results advance the current understanding for the design of personalized infant nutritional solutions and therapies in future.

Biorefinery upgrading of herbaceous biomass to renewable hydrocarbon fuels, Part 1: Process modeling and mass balance analysis

Process simulation has long been a well-established tool to track key operational, design, and mass and energy balance metrics for pre-commercial technologies such as advanced lignocellulosic biofuels. While tools such as this are well-documented in the public literature around 2nd-generation cellulosic ethanol technologies (which have been scaled up to commercial deployment to some degree over the past decade), such models and analysis information remain more sparse for more complex biorefinery pathways focused on producing drop-in hydrocarbon fuels and blend-stocks, particularly regarding information required to support air emissions or other environmental analysis. In this work, we summarize key details for an established “design case” modeling the conversion of herbaceous lignocellulosic biomass into a renewable diesel hydrocarbon blend-stock based on a representative lipid pathway from oleaginous yeast. The process is based on a biochemical deconstruction and upgrading approach utilizing deacetylation and dilute acid pretreatment, followed by enzymatic hydrolysis, fermentation, and catalytic upgrading of hydrolysate sugars to fuels. We provide key mass and energy balance outputs from the process models, with accompanying stream tables and component-level flowrates. A total of 12 model scenarios are presented spanning two feedstocks, three biorefinery scales, and two processing approaches for the lignin/residual solids waste streams. This “Part 1” manuscript presents the resulting impacts across the 12 cases on fuel yields and key output streams, focused here on direct biorefinery air emissions for selected components including CO 2 as well as sulfur (SOx) and nitrogen oxides (NOx). In the context of cleaner production, the latter focus on selected biorefinery air emission outputs establishes an initial baseline estimate and accompanying framework of the model cases, upon which an accompanying “Part 2” study will build to refine the values for these and other air pollutants across these scenarios, also considering mitigation options to comply with applicable regulatory standards. We also highlight further optimization opportunities based on potential tradeoffs identified here between air emissions versus life-cycle greenhouse gas profiles attributed to the disposition of lignin/residual solids.

Synergetic use of IASI profile and TROPOMI total-column level 2 methane retrieval products

Abstract. The thermal infrared nadir spectra of IASI (Infrared Atmospheric Sounding Interferometer) are successfully used for retrievals of different atmospheric trace gas profiles. However, these retrievals offer generally reduced information about the lowermost tropospheric layer due to the lack of thermal contrast close to the surface. Spectra of scattered solar radiation observed in the near-infrared and/or shortwave infrared, for instance by TROPOMI (TROPOspheric Monitoring Instrument), offer higher sensitivity near the ground and are used for the retrieval of total-column-averaged mixing ratios of a variety of atmospheric trace gases. Here we present a method for the synergetic use of IASI profile and TROPOMI total-column level 2 retrieval products. Our method uses the output of the individual retrievals and consists of linear algebra a posteriori calculations (i.e. calculation after the individual retrievals). We show that this approach has strong theoretical similarities to applying the spectra of the different sensors together in a single retrieval procedure but with the substantial advantage of being applicable to data generated with different individual retrieval processors, of being very time efficient, and of directly benefiting from the high quality and most recent improvements of the individual retrieval processors. We demonstrate the method exemplarily for atmospheric methane (CH4). We perform a theoretical evaluation and show that the a posteriori combination method yields a total-column-averaged CH4 product (XCH4) that conserves the good sensitivity of the corresponding TROPOMI product while merging it with the high-quality upper troposphere–lower stratosphere (UTLS) CH4 partial-column information of the corresponding IASI product. As a consequence, the combined product offers additional sensitivity for the tropospheric CH4 partial column, which is not provided by the individual TROPOMI nor the individual IASI product. The theoretically predicted synergetic effect is verified by comparisons to CH4 reference data obtained from collocated XCH4 measurements at 14 globally distributed TCCON (Total Carbon Column Observing Network) stations, CH4 profile measurements made by 36 individual AirCore soundings, and tropospheric CH4 data derived from continuous ground-based in situ observations made at two nearby Global Atmospheric Watch (GAW) mountain stations. The comparisons clearly demonstrate that the combined product can reliably detect the actual variations of atmospheric XCH4, CH4 in the UTLS, and CH4 in the troposphere. A similar good reliability for the latter is not achievable by the individual TROPOMI and IASI products.

Correlations of Dark Matter, Gas, and Stellar Profiles in Dark Matter Halos

Halos of similar mass and redshift exhibit a large degree of variability in their differential properties, such as dark matter, hot gas, and stellar mass density profiles. This variability is an indicator of diversity in the formation history of these dark matter halos that is reflected in the coupling of scatters about the mean relations. In this work, we show that the strength of this coupling depends on the scale at which halo profiles are measured. By analyzing the outputs of the IllustrisTNG hydrodynamical cosmological simulations, we report the radial- and mass-dependent couplings between the dark matter, hot gas, and stellar mass radial density profiles utilizing the population diversity in dark matter halos. We find that for the same mass halos, the scatters in the density of baryons and dark matter are strongly coupled at large scales (r > R 200), but the coupling between gas and dark matter density profiles fades near the core of halos (r < 0.3R 200). We then show that the correlation between halo profile and integrated quantities induces a radius-dependent additive bias in the profile observables of halos when halos are selected on properties other than their mass. We discuss the impact of this effect on cluster abundance and cross-correlation cosmology with multiwavelength cosmological surveys.

Physics-Informed Neural Networks Help Predict Fluid Flow in Porous Media

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 203033, “Prediction of Fluid Flow in Porous Media Using Physics-Informed Neural Networks,” by Muhammad M. Almajid, SPE, and Moataz O. Abu-Alsaud, SPE, Saudi Aramco. The paper has not been peer reviewed. The authors of the complete paper write that the realm of reservoir engineering is considered to belong to the small-data regime because of the complex physical systems involved and the inherent uncertainty of the problems. The objective of the paper is to present a physics-informed neural network (PINN) technique that is able to use information from the fluid-flow physics and observed data to model the Buckley-Leverett problem. Fractional-Flow Theory Through their study of fluid displacement in sands, Buckley and Leverett introduced the fractional-flow theory. The theory estimates the rate at which one fluid displaces another and, consequently, the change in fluid saturations. The theory has been applied to many fluid-flow processes in porous media such as waterflooding, carbonated waterflooding, alcohol flooding, miscible flooding, steam flooding, foam flooding, low-salinity waterflooding, and carbon sequestration. The authors use the fractional-flow theory to simulate the displacement of water-filled porous media by gas, a process detailed in the complete paper. Once the Buckley-Leverett solution is obtained, the saturation profile of gas or water can be plotted at different times. It is noteworthy that a gas viscosity of 0.2 cp in this case is used so that the shock is visually apparent in the Buckley-Leverett solution. Additionally, having this large of a gas viscosity is justified. For instance, foamed gas can develop apparent viscosities orders of magnitude larger than unfoamed gas. Fig. 1 plots the gas-saturation profile along the dimensionless distance. Obtaining the corresponding water-saturation profiles is trivial. The authors compare the analytical solution and the PINN prediction with respect to water saturation.