Water Frost Research Articles

Observations of Water Frost on Mars With THEMIS: Application to the Presence of Brines and the Stability of (Sub)Surface Water Ice

AbstractCharacterizing the exchange of water between the Martian atmosphere and the (sub)surface is a major challenge for understanding the mechanisms that regulate the water cycle. Here we present a new data set of water ice detected on the Martian surface with the Thermal Emission Imaging System (THEMIS). The detection is based on the correlation between bright blue‐white patterns in visible images and a temperature measured in the infrared that is too warm to be associated with ice and interpreted instead as water ice. Using this method, we detect ice down to 21.4°S, 48.4°N, on pole‐facing slopes at mid‐latitudes, and on any surface orientation poleward of 45° latitude. Water ice observed with THEMIS is most likely seasonal rather than diurnal. Our data set is consistent with near‐infrared frost detections and predictions by the Mars Planetary Climate Model. Water frost average temperature is 170 K, and the maximum temperature measured is 243 K, lower than the water ice melting point. Melting of pure water ice on the surface is unlikely due to cooling by latent heat during its sublimation. However, 243 THEMIS images show frosts that are hot enough to form brines if salts are present on the surface. The water vapor pressure at the surface, calculated from the ice temperature, indicates a dry atmosphere in early spring, during the recession of the ice cap. The large amount of water vapor released by the sublimation of warm frost cannot stabilize subsurface ice at mid‐latitudes.

Evidence for transient morning water frost deposits on the Tharsis volcanoes of Mars

The present-day water cycle on Mars has implications for habitability and future human exploration. Water ice clouds and water vapour have been detected above the Tharsis volcanic province, suggesting the active exchange of water between regolith and atmosphere. Here we report observational evidence for extensive transient morning frost deposits on the calderas of the Tharsis volcanoes (Olympus, Arsia and Ascraeus Montes, and Ceraunius Tholus) using high-resolution colour images from the Colour and Stereo Surface Imaging System on board the European Space Agency’s Trace Gas Orbiter. The transient bluish deposits appear on the caldera floor and rim in the morning during the colder Martian seasons but are not present by afternoon. The presence of water frost is supported by spectral observations, as well as independent imagery from the European Space Agency’s Mars Express orbiter. Climate model simulations further suggest that early-morning surface temperatures at the high altitudes of the volcano calderas are sufficiently low to support the daily condensation of water—but not CO2—frost. Given the unlikely seasonal nature of volcanic outgassing, we suggest the observed frost is atmospheric in origin, implying the role of microclimate in local frost formation and a contribution to the broader Mars water cycle.

Analysis of frost layer growth behavior on cryogenic surfaces in ultralow dew point environments by experimental tests and numerical simulations

Maintaining an ultralow dew point is essential for the operation of transonic cryogenic wind tunnels, as it significantly influences aerodynamic characteristics. Even in extremely dry conditions, minute quantities of frost can form on cryogenic surfaces, which compromises data quality. Conducting experiments on frost desublimation in such ultralow dew point environments poses significant challenges due to the demanding experimental conditions. Therefore, this study aimed to explore the desublimation characteristics of cryogenic surfaces in ultralow dew point environments and to address the challenges of experimental investigations under such extreme conditions. Initially, the study experimentally investigated frost formation by assessing the impact of various factors, such as temperature and water vapor content. It was observed that the type of frost formed depended on the water vapor content, and altering the surface temperature influenced the growth region of the frost crystals. The irregular growth of the frost layer on low-temperature surfaces was evident, as temperature markedly affected both the growth rate and the diffusion direction of frost formation. Moreover, the process of trace water frost formation was simulated using a dispersive multiphase model, predicting the frost layer's thickness. The numerical results suggest that the frost layer is micrometers thick, with a minimum thickness of 20 μm. A nonlinear relationship was identified between frost growth and dew point level. This research lays the groundwork for a deeper understanding of desublimation characteristics in ultralow dew point environments and for further investigation of low-temperature heat and mass transfer phenomena.

Water vapor condensation in optical instruments on Mars

Modern high-sensitivity spectrometers rely on photons reflecting thousands of times between extremely reflective mirrors to generate absorption pathlengths that are kilometers long. The absorption spectrum of trace gas species is enhanced when cooling the gas sample, however, should any atmospheric volatiles condense within the gas cell, the highly-reflective mirrors may become marred, drastically cutting down the effective optical path length. In the Martian atmosphere, the first volatile to condense is typically water vapor, thus understanding the variability of the water frost point is essential for determining the performance limit of any optical instrument. We will examine these performance limits and map the maximum temperatures at which water vapor will condense on the Martian surface with respect to a model instrument being prepared for flight. The variability of the frost point with time and solar longitude (Ls) therefore reveals areas of the Martian surface at which the precision of a high-sensitivity spectrometer is optimized. We find that the optimal performance is achieved during northern fall and winter (Ls = 180°–360°) at polar and mid-latitude locations in the northern hemisphere, and during northern spring (Ls = 0°–90°) at equatorial and mid-latitude locations in the southern hemisphere when the frost point reaches the lowest maximums.

MAVEN/IUVS Observations of OH Prompt Emission: Daytime Water Vapor in the Thermosphere of Mars

AbstractWe report the highest altitude detection of water vapor on Mars to date. The daytime limb observations by the Imaging Ultraviolet Spectrograph (IUVS) on the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft are of hydroxyl (OH) prompt emission near 308 nm, which is excited directly from the photodissociation of water vapor by the solar Lyman‐α flux. Average IUVS daytime water vapor densities near 130 km are 3 × 107 cm−3 around perihelion. The water vapor densities diurnally vary with a peak near midday and no detection at sunrise and sunset. To evaluate the large daytime water vapor densities for self‐consistency, we also report the simultaneous observation of OH solar fluorescence emission near 308 nm in the thermosphere, which enables the retrieval of OH densities. Using a one‐dimensional photochemical model initialized with the daytime IUVS water vapor densities, modeled peak OH densities are in good agreement with the observed IUVS peak OH densities. Because the observed thermospheric temperatures are controlled by solar insolation and cross the water frost point during the day, we suggest that the IUVS observed water vapor is created by the daily sublimation of water ice particles supplied from below. We discuss the implications of the IUVS observations on the present day loss of water vapor from Mars in the form of atomic hydrogen.

Experimental investigation of the pore fractal characteristics and damage degradation mechanism of sandstone after cyclic Freeze‒thaw treatments

To reveal the microscopic pore characteristics and strength weakening mechanism of rock under the influence of cyclic freeze-thaw treatment, uniaxial compression tests and MIP (mercury intrusion porosimetry) were conducted on red sandstone specimens with different numbers of freeze-thaw cycles (0, 20, 40, 60, and 80). The experimental results showed that cyclic F-T (freeze-thaw) treatment can lead to an increase in porosity and the expansion of the pore structure. Specifically, the porosity increased by nearly 30.22% from 8.467% without freeze-thaw to 11.026% after 80 freeze-thaw cycles. The distribution ratios of mesopores (2–10 μm) and micropores (less than 0.1 μm) changed from 0.7% to 19.9% without freeze‒thaw to 12.6% and 11.6% after 80 freeze‒thaw cycles, which showed an expansion trend from small to large pores. For the PFD (pore fractal dimension) of sandstone, three fractal models (capillary pressure model, Menger sponge model and thermodynamic model) were used to calculate the pore fractal dimension of different freeze-thaw cycles, which gradually increased with the increase in freeze‒thaw cycles. Specifically, the PFD increased by 3.02, 3.01 and 2.65% after 20, 40, 60, and 80 freeze-thaw cycles, respectively. Additionally, the PFD calculated by the capillary pressure model and Menger sponge model had piecewise characteristics, which can better characterize pore fractal characteristics with pore diameters less than 2 μm. In summary, based on thermodynamic theory and pore water frost heaving deformation theory, a freeze-thaw damage degradation model based on the porosity of a fractured rock mass was established, and the theoretical value obtained was in good agreement with the experimental results.

Research on high precision optical fiber acoustic emission system for weak damage location on concrete

• Concrete weak AE location requires high detection accuracy of the system. • Random fiber laser enables the system to pick up weak AE waves on concrete. • Simulation and tests verify that the system can detect concrete AE wave reliably. • Random fiber laser and adaptive search strategy ensure a high location accuracy. • Accurate time difference of arrival can be used for a high precision AE location. A high precision optical fiber acoustic emission (AE) locating system with designed random fiber lasers (RFLs) and a proposed adaptive time of arrival extraction strategy for weak damage source location on concrete is proposed. The low frequency-noise and narrow linewidth of RFLs enable the system to obtain a high signal detection resolution of 8.32 × 10 −7 m/s within 500 kHz. Meanwhile, an adaptive threshold search strategy to optimize the onset time of the AE wave, thus maintaining small location errors from the perspective of improving the time difference of arrival (TDOA). Then, AE source localization is transformed into a genetic algorithm optimization process with TDOA as a parameter. The reliability of the RFL sensor in detecting weak pseudo-damage source signals from concrete is verified by simulation and experiment on a concrete slab with dimensions of 0.9 m × 0.9 m × 0.1 m. A total of 64 pseudo damage source location tests are performed at 16 random points on a concrete slab surface. The maximum axial location error of the system is 2.78%. The root mean square errors and standard deviations of the absolute errors are 2.8 cm and 9 mm, respectively. The accuracy and robustness of location are analyzed. Finally, the proposed system is used to locate the plane mapping points of concrete specimens cracked by crack water frost heaving, and the locating accuracy is 93.4%.

Mechanical and Self-Healing Performance of Yellow River Alluvial Silt Treated with Composite Flexible Curing Agent

The silt in the Yellow River alluvial plain has low clay content, low cohesion and poor structure. Its stability has always been a difficult problem in the engineering field. In order to improve the engineering properties of the silt in the alluvial plain of the Yellow River, a new type of silt composite flexible curing agent was prepared by using sintered red mud and matrix asphalt as the main materials to comprehensively stabilize the silt. The aim of this study was to investigate the effects of sintered red mud-asphalt composite flexible curing agent on aged mechanical properties of treated silt, in which the replacement levels of the flexible curing agent below 10% by weight are compared. Apart from the compressive strength, the drying shrinkage, low temperature freeze-thaw and high temperature self-healing ability are measured. The test results show that the flexible curing agent has a positive effect on improving the mechanical properties of stabilized silt. The flexible curing agent series exhibit higher compressive strength, better water stability, resistance to freeze-thaw and high temperature self-healing ability, and lower drying shrinkage compared to silt and cement stabilized silt. The preferred dosage 4%~6% of the flexible curing agent is obtained by mechanical property analysis. The SEM images show that the incorporation of the flexible curing agent helps the silt form dense cementation and non-connected microporous structure, that is beneficial to the improvement of water stability and frost resistance. The asphalt component in the flexible curing agent can reorganize and diffuse in the soil, fill the internal pores and micro cracks, and realize the repair of soil damage and structural reinforcement.

Effect of temperature gradients on water migration, frost heave and thaw-settlement of a clay during freezing-thaw process

ABSTRACT During the freezing process, water migration is a decisive factor for the estimation of frost heave and thaw-settlements of fine and mixed-grain soils. One-dimensional freezing tests with and without a water supply were carried out. The influence of different temperature gradients of a saturated clay on parameters such as water intake, frost heave, and thaw-settlements is discussed here. A new approach is presented to describe the rate of water intake, which consists of three parameters. This study shows that all three parameters were influenced by the temperature gradient. This approach helps predict frost heave and thaw-settlement in cold regions.

Study on the Mechanical Properties and Design Parameters of Floor Slabs Waste Subgrade Filler

In recent years, there have been more and more studies on the use of construction and demolition waste (CDW) as subgrade filler. The physical performance indexes of a single material of floor slabs waste (FSW) are studied, which meet the requirements of subgrade specification. From the perspective of construction quality control, it is proposed that when FSW is used as subgrade filler, the compaction thickness and the maximum allowable particle size should be controlled according to different layers, and the gradation of subgrade filler is evaluated by using the nonuniformity coefficient (Cu) and curvature coefficient (Cc). The compaction test of FSW shows that the maximum dry density and optimum moisture content of different gradations do not change much. The crushing value under the freeze-thaw cycle is proposed to evaluate the frost resistance of FSW. The crushing value of FSW after water absorption and frost heaving changes a little. The CBR and resilience modulus tests were carried out on the FSW such that the results show that they have a good relationship and the relevant expressions under different compaction degrees are fitted. When performing on-site compaction testing, it is proposed that the upper roadbed adopts the sand replacement method according to the different layers of the FSW subgrade and the settlement discrepancy method should be adopted for other parts. Through laboratory tests and construction field detective, the quality control requirements, road performance indexes, and design indexes of FSW materials are put forward.

Evaluation of grainflow mechanisms for martian recurring slope lineae (RSL)

Recurring slope lineae (RSL) are dark narrow features that incrementally lengthen and fade at least once each Mars year. Their origin has remained enigmatic. We report quantitative modeling of three hypotheses related to triggering of over-steepened sand caches that result in dry-grain flow. First, sand could be supplied by either wind blowing upslope from within the crater or by wind blowing into the crater from the outside. Without cementation, grain flows should be directly correlated with temporal variations in potential sediment transport. Second, deliquesced perchlorate salts could increase soil cohesion; with the loss of water this soil cohesion may be reduced. The timing of accumulation versus release can be distinct from each other. Third, seasonal water frost could act in a similar cementation capacity. We assess these hypotheses using atmospheric modeling to determine wind speed, wind direction, temperature, and relative humidity at three craters (Rauna, Krupac, and Palikir) that host confirmed RSL and that cover a large latitudinal range. Overall, we find no convincing support for any of these hypotheses. Deliquescence is predicted to occur only at Rauna crater and its formation does not correlate with RSL activity. The occurrence of frost is inconsistently correlated with RSL activity among the three craters. Upslope winds at Palikir crater transport a significant amount of sediment only when RSL are active. However, the largest sediment flux into the crater is also during periods of RSL activity, thus supporting both internal and external contributions. Sediment transport into Krupac crater to S- and SW-facing slopes is also maximized when RSL are active, but there is no correlated upslope transport. This supports the hypothesis that RSL formation is dominated by external sediment supply alone. On the other hand, W- and NW-facing Krupac and all RSL at Rauna show no correlations with any directional sediment transport. Nonetheless, we suggest that the mixed success of the external sediment transport model is still quantitatively better than any competitor (including water), and that we simply lack the model and data resolution to treat RSL at the required meter scales. In all of the aeolian models, favorably-directed potential sediment flux greatly exceeds the volume of sand that must be displaced to form RSL. We conclude that RSL may require a particular combination of favorable strong winds, local sediment traps, and a supply of sand grains that easily saltate on Mars (~100 μm in diameter).

Water absorptivity and frost resistance performance of self-ignition coal gangue autoclaved aerated concrete

Self-ignition coal gangue (SCG) used as one of precursors to fabricate autoclaved aerated concrete (AAC). Aiming at studying water absorptivity and frost resistance performance of SCG-based AAC (SCGAAC), three-period water absorption tests and freeze-thaw tests were carried out and the corresponding results were recorded and analyzed. In order to modify the water absorptivity of SCGAAC, foam stabilizer was applied to adjust pore structure while calcium stearate was expected to change hydrophilic feature of SCG. It was demonstrated that the compressive strength of SCGAAC containing foam stabilizer or calcium stearate declined at different levels. For water absorption, foam stabilizer failed to decrease the water content and even increased water absorption rates. Calcium stearate controlled water absorption rate successfully although the ultimate water content hardly reduced. All of the SCGAAC samples exhibited intact appearance after 50 freeze-thaw cycles and showed excellent frost resistance performance. Three models were proposed to predict water absorptivity and frost resistance performance of SCGAAC and the corresponding prediction results matched test resulted well.

Cloud Formation From a Localized Water Release in the Upper Mesosphere: Indication of Rapid Cooling.

Polar mesospheric clouds (PMCs) occur in the summer near 82 ‐85km altitude due to seasonal changes of temperature and humidity. However, water vapor and associated PMCs have also been observed associated with rocket exhaust. The effects of this rocket exhaust on the temperature of the upper mesosphere are not well understood. To investigate these effects, 220 kg of pure water was explosively released at 85 km as part of the Super Soaker sounding rocket experiment on the night of January 25–26, 2018 at Poker Flat Research Range (65°N, 147°W). A cloud formed within 18 s and was measured by a ground‐based Rayleigh lidar. The peak altitude of the cloud appeared to descend from 92 to 78 km over 3 min. Temperatures leading up to the release were between 197 and 232 K, about 50 K above the summertime water frost point when PMCs typically occur. The apparent motion of the cloud is interpreted in terms of the expansion of the explosive release. Analysis using a water vapor radiative cooling code coupled to a microphysical model indicates that the cloud formed due to the combined effects of rapid radiative cooling (∼25 K) by meter‐scale filaments of nearly pure water vapor (∼1 ppv) and an increase in the frost point temperature (from 150 to 200 K) due to the high concentration of water vapor. These results indicate that water exhaust not only acts as a reservoir for mesospheric cloud production but also actively cools the mesosphere to induce cloud formation.

单向冻结黏性土水热特性冻胀试验研究

单向冻结黏性土水热特性冻胀试验研究

NONSTANDARD RAW MATERIALS FOR ANORTHITE CERAMICS PRODUCTION

The paper analyzes the Russian and foreign research into the use of nonstandard raw materials in the production of constructional anorthite ceramics. The raw materials with different chemical composition are investigated. It is shown that the use of nonstandard raw materials in the ceramic mixture makes it possible to obtain constructional products with 43.1 MPa compressive strength, 2150 kg/m3 density, about 7 % water absorption and frost resistance that meets the requirements of regulatory documents. The physical and mechanical properties are obtained due to the anorthite phase containing in the composition of end ceramic products, which is confirmed by the X-ray phase and microscopic analyses.

Diagnostics of frost water accumulation and technological regulation of the construction of the roadbed

The relevance and content of technological regulation of production processes with continuous monitoring of changes in soil characteristics in areas of high-temperature permafrost due to the extremely unstable state of the roadbed during the work are substantiated.
 Aim: Formation of a technical and technological system that operates on the principles of direct and feedback between the characteristics of geotechnical structures and the parameters of construction equipment for the most efficient and high-quality production of works.
 Methods: Methods of technological regulation for the purpose of reducing soil moisture at the stage of freezing water accumulation at the base of the mound being built are proposed.
 Conclusion: The expediency of using opto-fiber cable for monitoring the state of the roadbed as a continuous sensor along the length of the route that can register changes in soil properties during the construction of Railways is shown.

Mars: Quantitative Evaluation of Crocus Melting behind Boulders

Abstract The possibility of liquid water on present-day Mars has been debated for half a century. Melting is physically difficult under Martian environmental conditions, because with the total pressure of the atmosphere near the triple point pressure of water, evaporative cooling of ice is high near the melting point. Here, a suite of quantitative models is used to investigate whether melting of seasonal water frost can occur on present-day Mars. An updated and generalized parameterization is derived for the turbulent convective heat flux that results from the buoyancy of water vapor. A three-dimensional surface energy balance model is used to calculate surface temperatures; it includes terrain shadowing, self heating, and subsurface conduction. Protruding topography creates locations that experience a rapid transition from conditions where water frost accumulates to high solar energy input. Beyond the pole-facing side of a boulder, CO2 and frost can accumulate seasonally, and once the Sun reemerges and the CO2 frost disappears, the water frost is heated to near melting temperature within one or two sols. Dust contained in the CO2 frost facilitates the formation of a protective sublimation lag. Temperatures within about 10 K of the melting point are reached within one or two sols after the end of water frost accumulation. For expected sublimation lag thicknesses, evaporative cooling is not significantly reduced. Overall, melting of pure water ice is not expected under present-day Mars conditions. However, at temperatures that are readily reached, seasonal water frost can melt on a salt-rich substrate. Hence, crocus melting behind boulders can lead to the formation of brines under present-day Mars conditions.

A Simplified Viscoelastic Solution of the Frost Heaving Force of Cavity Water behind Tunnel Linings

With the high demand for construction of tunnels in China’s severe cold regions, the problem of frost heaving has become an important factor that endangers tunnel safety. This paper attempts to investigate the effect of frost heave of cavity water that widely exists in the tunneling engineering on the tunnel stability. According to the actual deformation of the surrounding rock of the tunnel, the viscoelastic behavior is considered to the surrounding rock. On the premise of the elastic solution of stagnant water frost heave, the viscoelastic solution of frost heaving pressure is deduced by Laplace transform using the generalized Kelvin model based on the elastic‐viscoelastic correspondence principle. The frost heaving force is analyzed through a case study with variations in the size of the cavity defect as well as the constitutive model parameters. It is concluded that the frost heaving force increases with the cavity defect size; over time, the frost heaving force gradually increases, but it will eventually stabilize. It is found that when the frost heaving force reaches a certain level, the surrounding rock with low strength or the lining with insufficient strength will crack, and the frost heaving force will not continue to increase.

High‐Resolution Thermal Environment of Recurring Slope Lineae in Palikir Crater, Mars, and Its Implications for Volatiles

AbstractA thermophysical model for rough terrain is developed that is capable of processing spatial domains of megapixel size. This computational advance makes it possible to characterize thermal environments on Mars at unprecedented scale and at a resolution of 1 m per pixel. The model is applied to Palikir Crater, Mars, where many recurring slope lineae (RSL) are located, often in bedrock alcoves. In areas with RSL, subsurface water ice is not stable, that is, any subsurface ice is lost to the atmosphere in the long term. On large portions of the craters walls, water frost accumulates continuously for up to hundreds of sols each Mars year, but no relation is found between the location of RSL and seasonal water frost accumulation. Some RSL do not have access to even 1 m2 of water frost, at any time of the year. Where water frost is present, it stops accumulating in early southern spring at the latest, long before major RSL activity. Based on the model results, neither CO2 frost, perennial subsurface ice, nor seasonal water frost patches (>1 m2) are connected with RSL activity.

The study of strength of sandy soils reinforced with cement with the addition of «DorZem Ds-1», for use in the construction of foundations of roads

Currently, road organizations are faced with the problem of increasing the bearing capacity of the layers of road pavement. This problem can be solved by using new design solutions, technologies and materials. The use of local road construction materials, industrial waste, stabilization and strengthening of soils in the foundations of the pavement will increase the bearing capacity of the pavement, reduce transportation costs for the delivery of materials and reduce the cost of construction. Strengthening of soils – a set of measures to improve their strength and water resistance. In the process of strengthening the soils for use in the foundations of the pavement the main task is to obtain a new building material with the desired structural and mechanical properties. The process of strengthening is a process of structure formation, new connections are created by influencing the soil structure-forming binders (cement, lime, organic binders, etc.). When stabilizing the properties of soils, mainly the content of water in the soil, use stabilizers. They usually are water-repellent additives. When strengthening the soil can use different types of modifiers: Russian and foreign. We used the modifier «Dorzem DS-1». It is a powdery substance. The use of «Dorzem DS-1» fundamentally changes the process of crystallization. The mechanism of binding of soil particles changes from «bonding» to the «plexus» – when hitting the «Dorzem DS-1» in the ground begin to form crystalline dlinnorylye of communication, which «envelop» all the elements. On the strength of they, like Kevlar thread (strong, flexible). Due to this, strong, wear-resistant structures are obtained (cement, lime, organic binders, etc.). Several years in a row on the instructions of road construction organizations of the city of Bryansk employees of the Department «Roads» BGITU conducted research to strengthen clay soils. Recently, road organizations began to prefer sandy soils. They are enough in the Bryansk region, but they are mostly fine-grained and dusty. Performing the task of LLC «Bryansk road construction company №1», we have previously been installed grain composition of sandy soil. Its density and humidity were determined. From the silty sand specimens have been fabricated reinforced soil using Portland cement grade 400, modifiers the «Palace area DS-1» and water for mixing, tested. The samples had cuboid shape with dimensions: 10х10х10 cm and 7х7х7 cm. The compressive strength was determined as the average value of four samples in a series made from a mixture of one composition. The Age of the samples during the tests was 28 days, which corresponds to the brand strength of the main mineral binder of the 1st type (Portland cement) – GOST23558-94 p. 6.1. Laboratory tests of samples from the soil treated with cement and cement plus the additive «Dorzem DS-1» showed that the greatest strength can be achieved by adding to the soil 12 % of the cement over the weight of the soil and 3 % of the additive. The strength obtained in this case is 4,882 MPa, i.e. about 5 MPa. In the manufacture of samples of hardened soil cement with one (12 % in excess of the weight of the clay) strength is much lower 3,712 MPa. This pattern is observed in other formulations of recipes. The use of additives «Dorzem DS-1» in strengthening the soil can improve the performance of water resistance and frost resistance, eliminate the formation of cracks.