Macrophysical Parameters Research Articles

MATHEMATICAL MODELING AND EXPERIMENTAL INVESTIGATION OF THE PROCESS OF NON-STATIONARY HEAT TRANSFER IN A BLOCK FOAM GLASS SAMPLE AT THE ANNEALING STAGE

The specifics of the technology for the production of block foam glass are presented, the results of experimental studies of the properties of the material are presented, a method for improving production based on mathematical modeling of heat transfer processes is proposed. It is shown that the processes of high-temperature processing of foam glass make a key contribution to the formation of a high-quality porous structure, therefore, this area of ​​research needs the development of adequate methods for calculating the main macrophysical parameters based on the theory of heat transfer. A technique for checking the adequacy of the mathematical model of heat transfer is presented using the example of spontaneous cooling of a foam glass block. The entire procedure for checking the adequacy of the mathematical model was carried out in three stages. At the first stage, the degree of validation of the model is assessed, functional dependencies with the results of an experimental study based on the Pearson determination coefficient. The main stage includes the evaluation of the confidence intervals of the experimental data and the discussion of the convergence of the results of the analytical calculation with the results of the experimental data. The final stage, at which a comprehensive assessment of the adequacy of the mathematical model is given, includes both the results of the preparatory and the main stages. The results of the study showed that it can be concluded that the calculated data have sufficient convergence with the experimental data and indicate the adequacy of the developed mathematical model of heat transfer.

Reduced electric field and gas temperature effects on chemical product dynamics in air surface dielectric barrier discharges: from macro-physical parameters to micro-chemical mechanisms.

To gain insights into the mechanisms of plasma chemical product interactions, the dynamic changes of the surface dielectric barrier discharge (SDBD) products are experimentally related to the reduced electric field and gas temperature. The higher applied voltage and frequency cause faster product changes from the O3-containing to the O3-free state, while raising the electron energy and gas temperature. The electron energy affects the electron collision reactions and the production of various reactive species, steering the chemical reactions towards the predominant production of NO over O3. The gas temperature affects the generation and quenching rates of the key products. Collectively, this work bridges macro-physical parameters and micro-chemical mechanisms through the electron energy and gas temperature effects, and contributes to better understanding of the physico-chemical processes in low-temperature plasmas.

Influence of the crust on the neutron star macrophysical quantities and universal relations

Background: Measurements of neutron-star macrophysical properties thanks to multimessenger observations offer the possibility to constrain the properties of nuclear matter. Indeed, cold and dense matter as found inside neutron stars, in particular in their core, is not accessible to terrestrial laboratories.Purpose: We investigate the consequences of using equations of state that employ models for the core and the crust that are not calculated consistently on the neutron-star macrophysical properties, on some of the so-called universal relations and on the constraints obtained from gravitational-wave observations.Methods: We use various treatments found in the literature to connect together nonconsistent core and crust equations of state. We then compute the mass, the radius, the tidal deformability, and the moment of inertia for each model. Finally, we assess the discrepancies in the neutron-star macrophysical properties obtained when consistent models for the whole star and nonconsistent ones are employed.Results: The use of crust models nonconsistent with the core introduces an error on the macrophysical parameters which can be as large as the estimated accuracy of current and next-generation telescopes. The precision of some of the universal relations reported in the literature is found to be overestimated. We confirm that the equation of the crust has limited influence on the macrophysical properties.Conclusions: The discrepancy between results obtained for a fully consistent equation of state and a nonconsistent one can be reduced if one connects the core and the crust models at baryon densities around 0.08--$0.1\phantom{\rule{4pt}{0ex}}{\mathrm{fm}}^{\ensuremath{-}3}$. The equation of the crust cannot be probed with current multimessenger observations and near-future ones.

The mathematical model of stress sensitivities on tight reservoirs of different sedimentary rocks and its application

In this paper, five types of sedimentary rocks (the Turbidite, the Beach bar sand, the Glutenite and the two outcrop cores) with permeability (k，10−3μm2) grades (k < 0.1, 0.1＜k ≤ 0.3, 0.3＜k ≤ 0.5, 0.5＜k ≤ 1.0, 1.0＜k ≤ 3.0) are studied for the building of the model. The uniaxial compression tests, the stress sensitivity tests, and the CT structure scanning have been done, then the data and the curves obtained from the lab are carefully analyzed and examined. Studies on the grain sizes, the components ratios of the different grains, and the original pore structures are conducted in order to get the stress sensitivities of the rocks. Those of the Glutenite, the Turbidite and the Beach bar sand with the same permeability level (k ≤ 0.1 × 10−3μm2) are found having the order of stress sensitivity from high to low, and the maximum drops of permeability is range from 20.8% to 30.7%. Based on the experiment results, combined with the unequal diameter tortuous capillary bundle model and the contact deformation theory of Hertz, a mathematical model on stress sensitivities of tight reservoirs is established, which takes the characteristic parameters (Young's moduli, Poisson's ratios) of the reservoir rock materials, the pore structure parameters (the pore radii, the throat radii), and the macro physical parameters (the original permeability values) into account. The calculation error of the model is 2.6%. Finally, taking the actual data of the tight reservoirs in Jiyang Depression of Bohai Bay Basin as an example, this model is introduced into productivity equation to predict the production under the different formation pressures. It is suggested that the formation energy retention rate of the Glutenite reservoir to be above 0.9, the Turbidite reservoir above 0.85, and the Beach bar sand reservoir above 0.78.

Space‐Based Analysis of the Cloud Thermodynamic Phase Transition for Varying Microphysical and Meteorological Regimes

AbstractPhase transitions leading to cloud glaciation occur at temperatures that vary between 38°C and 0°C depending on aerosol types and concentrations, the meteorology, and cloud microphysical and macrophysical parameters, although the relationships remain poorly understood. Here, we statistically retrieve a cloud glaciation temperature from two passive space‐based instruments that are part of the NASA/CNES A‐Train, the POLarization and Directionality of the Earth's Reflectances (POLDER) and the MODerate resolution Imaging Spectroradiometer (MODIS). We compare the glaciation temperature for varying bins of cloud droplet effective radius, latitude, and large‐scale vertical pressure velocity and specific humidity at 700 hPa. Cloud droplet size has the strongest influence on glaciation temperature: For cloud droplets larger than 21 m, the glaciation temperature is 6°C higher than for cloud droplets smaller than 9 m. Stronger updrafts are also associated with lower glaciation temperatures.

Modeling of Macro-Physical Parameters of Foam Glass under Exposure of Cyclic Thermal Effects

The process of the raw materials mixture heat treatment in the foam glass production is of great importance in the formation of the finished product thermal characteristics. Selection of optimal temperature regimes at the stages when the process of glass particles melting is activated and thermal decomposition of the gasifier occurs is of particular importance. Otherwise, a situation when the gasifier has decomposed by mass on the layers close to the material surface at that the reaction has not been initiated at the raw materials mixture center may emerge. The problem can be solved by the uniform heating throughout the raw materials mixture entire volume. The fact that excessive heating can entail additional financial costs for manufacturers’ energy resources and as a result the cost of the material can be increased and affect its competitiveness among thermal insulation materials should be taken into account. A method for calculating temperature fields allowing to simulate the thermophysical heating process in the center of the material under study on the basis of its surface temperature indicators has been presented in the paper. Such an approach may make calculation of the rational time intervals for the raw material mixture heat treatment prior to the foaming stages and partially optimization of the production process possible.

Insight into the chemical reaction process of coal self-heating after N2 drying

It is generally considered that changes in physical rather than chemical structures are responsible for the increase in the spontaneous combustion tendency of coal after inert drying. In this paper, an isothermal flow reactor was combined with FTIR and ESR techniques to study the room temperature oxidation of coal samples under the effects of drying temperatures, numbers of drying-oxidation cycles and anaerobic heating temperatures. Macro-physical parameters such as gaseous generation, oxygen consumption, coal core temperature and micro-chemical structural parameters such as functional groups and free radicals were examined. After coal drying, the thermal decomposition of oxygen-containing functional groups generates free radical active sites, which can be oxidized and are exothermic at room temperature, accompanied by the generation of large amounts of CO and CO2 gaseous products. In addition, the active sites and oxygen-containing functional groups can be transformed into one another under certain conditions. The results indicate that the inherent reason responsible for self-heating and uncontrolled spontaneous combustion of N2-dried coal is the room temperature oxidation of the active sites, especially the room temperature oxidation of the secondary active sites generated by thermal decomposition of the oxygen-containing functional groups. The results presented in this research have applications to reveal the chemical reaction mechanism determining why lignite is more prone to spontaneous combustion after inert drying.

Long-Range Transport of Water Channelized through the Southern Subtropical Jet

In this study, an air mass (containing a cirrus cloud) was detected by light detection and ranging (lidar) above São Paulo (Brazil) in June 2007 and tracked around the globe, thanks to Lagrangian calculations as well as ground-based and satellite observations. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data were also used to provide locations of occurrence of cirrus around the globe and extract their respective macro physical parameters (altitude and temperature). An analysis of the air mass history based on Lagrangian trajectories reveals that water coming from the Equator is channelized through the southern subtropical jet for weeks. In this case, the back-trajectories showed that the cirrus cloud detected at São Paulo was a mixture of air masses from two different locations: (1) the active convective area located around the Equator, with transport into the upper troposphere that promotes cirrus cloud formation; and (2) the South Pacific Ocean, with transport that follows the subtropical jet stream (STJ). Air masses coming from equatorial convective regions are trapped by the jet, which contributes to maintaining the lifetime of the cirrus cloud for a few days. The cloud disappears near the African continent, due to a southern excursion and warmer temperatures, then reappears and is detected again by the lidar system in São Paulo after 12 days. The observed cloud is located at a similar altitude, revealing that sedimentation is small or compensated by radiative uplift.

European In-Situ Snow Measurements: Practices and Purposes.

In-situ snow measurements conducted by European institutions for operational, research, and energy business applications were surveyed in the framework of the European Cooperation in Science and Technology (COST) Action ES1404, called “A European network for a harmonised monitoring of snow for the benefit of climate change scenarios, hydrology, and numerical weather prediction”. Here we present the results of this survey, which was answered by 125 participants from 99 operational and research institutions, belonging to 38 European countries. The typologies of environments where the snow measurements are performed range from mountain to low elevated plains, including forests, bogs, tundra, urban areas, glaciers, lake ice, and sea ice. Of the respondents, 93% measure snow macrophysical parameters, such as snow presence, snow depth (HS), snow water equivalent (SWE), and snow density. These describe the bulk characteristics of the whole snowpack or of a snow layer, and they are the primary snow properties that are needed for most operational applications (such as hydrological monitoring, avalanche forecast, and weather forecast). In most cases, these measurements are done with manual methods, although for snow presence, HS, and SWE, automatized methods are also applied by some respondents. Parameters characterizing precipitating and suspended snow (such as the height of new snow, precipitation intensity, flux of drifting/blowing snow, and particle size distribution), some of which are crucial for the operational services, are measured by 74% of the respondents. Parameters characterizing the snow microstructural properties (such as the snow grain size and shape, and specific surface area), the snow electromagnetic properties (such as albedo, brightness temperature, and backscatter), and the snow composition (such as impurities and isotopes) are measured by 41%, 26%, and 13% of the respondents, respectively, mostly for research applications. The results of this survey are discussed from the perspective of the need of enhancing the efficiency and coverage of the in-situ observational network applying automatic and cheap measurement methods. Moreover, recommendations for the enhancement and harmonization of the observational network and measurement practices are provided.

Effects of Wintertime Polluted Aerosol on Clouds over the Yangtze River Delta: Case Study

ABSTRACT The effects of aerosol on clouds are examined over the Yangtze River Delta (YRD) using 3 months of satellite data from the polluted wintertime from December 2013 to February 2014. The relationships between aerosol properties, and cloud micro- and macro-physical parameters are analyzed in detail to clarify the differences in cloud development under various aerosol and meteorological conditions. Complex relationships between the aerosol optical depth (AOD), and the cloud droplet radius (CDR), liquid water path (LWP) and cloud optical thickness (COT) exist in four regions of interest (ROIs). High aerosol loading does not obviously affect LWPs and COTs; in fact, aerosols inhibit development of low- and medium-low clouds over coastal areas—an effect that is more pronounced in low clouds (< 5 km) than high ones. Low aerosol loading plays a positive role in promoting the COT of high- and low-clouds over areas dominated by maritime aerosol. Aerosol loading exerts a significant influence on COTs, LWPs and CDRs in valley and coal industry districts except during high-cloud conditions. The ranges of COTs, LWPs and CDRs in dry-polluted areas are lower than in other places, which suggests that dust aerosol has little effect on cloud properties. Synoptic conditions also strongly impact cloud distribution, in particular, an unstable synoptic condition leads to cloud development on a larger horizontal and vertical scale. Ground pollution enhances the amount of low-level cloud cover even under stable conditions. Aerosol plays an important role in wintertime cloud evolution in the low layers of the troposphere (< 5 km) when the atmosphere is stable.

Calculating the thermodynamic characteristics of hydrophobic hydration of chromium(III) and cobalt(III) tris-acetylacetonates in water and regularities of their solvation in aqueous alcoholic solvents

Based on the scaled-particle theory, the Gibbs energy of the formation of cavities in the structure of water and some alcohols are calculated for the processes of dissolution of cobalt(III) and chromium(III) tris-acetylacetonates. The contribution from the hydrophobic hydration of the tris-acetylacetonate molecules in water is calculated. The location of the inversion area is clarified for a number of aqueous alcoholic solvents, and the effect the solvent’s macrophysical parameters have on the patterns of tris-acetylacetonate solvation is analyzed.

A 35-GHz Polarimetric Doppler Radar for Long-Term Observations of Cloud Parameters—Description of System and Data Processing

AbstractA 35-GHz radar has been operating at the Meteorological Observatory Lindenberg (Germany) since 2004, measuring cloud parameters continuously. The radar is equipped with a powerful magnetron transmitter and a high-gain antenna resulting in a high sensitivity of −55 dBZ at 5-km height for a 10-s averaging time. The main purpose of the radar is to provide long-term datasets of cloud parameters for model evaluation, satellite validation, and climatological studies. Therefore, the system operates with largely unchanged parameter settings and a vertically pointing antenna. The accuracy of the internal calibration (budget calibration) has been appraised to be 1.3 dB. Cloud parameters are derived by two different approaches: macrophysical parameters have been deduced for the complete period of operation through combination with ceilometer measurements; a more enhanced target classification and the calculation of liquid and ice water contents are realized by algorithms developed in the framework of the European CloudNet project.

A new WRF-Chem treatment for studying regional-scale impacts of cloud processes on aerosol and trace gases in parameterized cumuli

Abstract. A new treatment of cloud effects on aerosol and trace gases within parameterized shallow and deep convection, and aerosol effects on cloud droplet number, has been implemented in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) version 3.2.1 that can be used to better understand the aerosol life cycle over regional to synoptic scales. The modifications to the model include treatment of the cloud droplet number mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. These changes have been implemented in both the WRF-Chem chemistry packages as well as the Kain–Fritsch (KF) cumulus parameterization that has been modified to better represent shallow convective clouds. Testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS). The simulation results are used to investigate the impact of cloud–aerosol interactions on regional-scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column-integrated BC can be as large as −50% when cloud–aerosol interactions are considered (due largely to wet removal), or as large as +40% for sulfate under non-precipitating conditions due to sulfate production in the parameterized clouds. The modifications to WRF-Chem are found to account for changes in the cloud droplet number concentration (CDNC) and changes in the chemical composition of cloud droplet residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to the latest version of WRF-Chem, and it is anticipated that they will be included in a future public release of WRF-Chem.

Radiative effect of dust aerosols on cloud microphysics and meso-scale dynamics during monsoon breaks over Arabian sea

During monsoon breaks (large scale rainfall below the long term normal), dry air laddened with dust aerosols intrude over central India through Arabian sea (AS) from West Asian desert regions. To understand the effect of these dust aerosols on marine clouds over AS during monsoon breaks, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and Cloud and the Earth's Radiant Energy System (CERES) data have been analyzed for the period 2007 to 2013. The vertical profile of dust backscatter coefficient (DBS) showed an elevated layer between 2 and 5 km and the maximum heating rate observed is 9 K/Day which is higher by 3 K/day as compared to the heating observed in June to September (JJAS) mean. Semi-direct effect due to the interaction of the long range transported dust with pristine cloud environment is observed in both warm and cold clouds. Significant differences in shortwave and longwave fluxes at the top of the atmosphere (TOA), cloud micro and macrophysical parameters are observed between the clouds with and without dust. Also, the percentage differences are more in cold clouds as compared to warm clouds. Dust induced semi-direct effect is found to be more pronounced in cold clouds, while indirect effect in warm clouds. Zonal anomalies of dynamical parameters due to dust induced heating, affect the circulation patterns in the immediate meso-scale environment, which strengthen/extend the monsoon break situation.

Linear and circular polarimetry observations of gamma-ray burst afterglows

Follow-up observations of large numbers of gamma-ray burst (GRB) afterglows, facilitated by the Swift satellite, have produced a large sample of spectral energy distributions and light curves, from which the basic micro- and macrophysical parameters of afterglows may be derived. However, a number of phenomena have been observed that defy explanation by simple versions of the standard fireball model, leading to a variety of new models. Polarimetry has shown great promise as a diagnosis of afterglow physics, probing the magnetic field properties of the afterglow and geometrical effects (e.g. jet breaks). Unfortunately, high quality polarimetry of a significant sample of afterglows is difficult to acquire, requiring specialised instrumentation and observing modes. In this talk I will review the recent successes in afterglow polarimetry, also showing first results of new instruments and observing campaigns. I will particularly focus on jet breaks.

MODIS Cloud-Top Property Refinements for Collection 6

AbstractThis paper summarizes the Collection-6 refinements in the Moderate Resolution Imaging Spectroradiometer (MODIS) operational cloud-top properties algorithm. The focus is on calibration improvements and on cloud macrophysical properties including cloud-top pressure–temperature–height and cloud thermodynamic phase. The cloud phase is based solely on infrared band measurements. In addition, new parameters will be provided in Collection 6, including cloud-top height and a flag for clouds near the tropopause. The cloud parameters are improved primarily through 1) improved knowledge of the spectral response functions for the MODIS 15-μm carbon dioxide bands gleaned from comparison of coincident MODIS and Atmospheric Infrared Sounder (AIRS) radiance measurements and 2) continual comparison of global MODIS and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) instantaneous cloud products throughout the course of algorithm refinement. Whereas the cloud-top macrophysical parameters were provided through Collection 5 solely at 5-km spatial resolution, these parameters will be available additionally at 1-km spatial resolution in Collection 6.

Retrieval of macrophysical cloud parameters from MIPAS: algorithm description

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard ENVISAT has the potential to be particularly useful for studying high, thin clouds, which have been difficult to observe in the past. This paper details the development, implementation and testing of an optimal-estimation-type retrieval for three macrophysical cloud parameters (cloud top height, cloud top temperature and cloud extinction coefficient) from infrared spectra measured by MIPAS. A preliminary estimation of a parameterisation of the optical and geometrical filling of the measurement field-of-view by cloud is employed as the first step of the retrieval process to improve the choice of a priori for the macrophysical parameters themselves. Preliminary application to single-scattering simulations indicates that the retrieval error stemming from uncertainties introduced by noise and by a priori variances in the retrieval process itself is small – although it should be noted that these retrieval errors do not include the significant errors stemming from the assumption of homogeneity and the non-scattering nature of the forward model. Such errors are preliminarily and qualitatively assessed here, and are likely to be the dominant error sources. The retrieval converges for 99% of input cases, although sometimes fails to converge for vetically-thin (&lt;1 km) clouds. The retrieval algorithm is applied to MIPAS data; the results of which are qualitatively compared with CALIPSO cloud top heights and PARASOL cloud opacities. From comparison with CALIPSO cloud products, it must be noted that the cloud detection method used in this algorithm appears to potentially misdetect stratospheric aerosol layers as cloud. This algorithm has been adopted by the European Space Agency's "MIPclouds" project.

Effect of Macrophysical Parameters of Clouds on Broadband Solar Radiation (295–2800 nm) at a Subtropical Location

The present study describes the effect of clouds (macro-physical parameters) on global solar radiation (G). Data from four years of hourly measurements of G on a horizontal surface were used. These data were collected at the South Valley University (SVU) meteorological research station (26.2°N, 32.7°E, 96 m above mean see level. In addition, the cloud modification factor for G (CMFG) was estimated in three cases: high-level, mid-level, and low-level clouds. For every level, the variation of hourly CMFG as a function of cloud amount (CA) was illustrated. A third-order polynomial between hourly values of CMFG and CA was established. Furthermore, the effect of CA in the attenuation of G relative to its corresponding value in cloudless conditions is discussed. For cloud cover > 88%, G was reduced by 54%, 34%, and 28% by low-, mid-, and high-level clouds, respectively.

Additional cyclic strain hardening and its relation to material structure, mechanical characteristics, and lifetime

The authors have analyzed the susceptibility of metallic materials to cyclic strain hardening depending on both their microphysical characteristics and macrophysical parameters represented by standard mechanical characteristics. At the microlevel, the degree of additional hardening is related to the material stacking fault energy. The materials with a high level of the stacking fault energy do not exhibit additional cyclic hardening under non-proportional loading, while those with a low energy are susceptible to a considerable strain hardening. For the macrolevel, on the basis of analysis of the mechanical properties of metallic materials, the authors have derived a correlation dependence between the hardening levels under static and cyclic loading. An approximate quantitative method to determine maximum strain hardening levels under non-proportional low-cycle strain-controlled loading is proposed. The lifetime under non-proportional loading has been shown to correlate well with the level of additional hardening.