Salt Lake Region Research Articles

Mechanical Properties, Corrosion Damage Evolution Laws, and Durability Deterioration Indicators of High-Performance Concrete Exposed to Saline Soil Environment for 8 Years

Most of the current studies rely on simulated brine corrosion environments and lack long-term investigations into concrete corrosion damage evolution under actual corrosive conditions. In this paper, high-performance concrete (HPC) with various mix ratios is designed in the context of the Qinghai Salt Lake region in China, and the evolution of corrosion damage of HPC with different water–binder ratios (W/B) and different fly ash (FA) admixtures under long-term field exposure conditions is obtained by testing the ultrasonic velocity and strengths of the HPC in the field exposure of the HPC in the Qinghai Salt Lake region. The results show that the corrosion resistance of HPC is related to its water–binder ratio and mineral admixture type and dosage under the exposure of 8 years in Qinghai Salt Lake area. HPC with a fly ash dosage of 15–35% and silica fume dosage of 10% exhibits better corrosion resistance when the water–binder ratio (W/B) is between 0.24 and 0.38. The dependence relationship between the corrosion resistance coefficient of HPC and the relative dynamic elastic modulus (Erd) and 28 d standard maintenance strength was also established. The Erd of HPC with a corrosion resistance coefficient of 0.80 or above was 0.73–0.93, not 0.60, which provides an important experimental basis for determining the corrosion damage index of HPC in the high-saline brine environment of the salt lake.

Spatio-temporal change and driving mechanisms of land use/cover in Qarhan Salt Lake area during from 2000 to 2020, based on machine learning

The significance of land use classification has garnered attention due to its implications for climate and ecosystems. This paper establishes a connection by introducing and applying automatic machine learning (Auto ML) techniques to salt lake landscape, with a specific focus on the Qarhan Salt Lake area. Utilizing Landsat-5 Thematic Mappe (TM) and Landsat-8 Operational Land Imager (OLI) imagery, six machine learning algorithms were employed to classify eight land use types from 2000 to 2020. Results show that XGBLD performed optimally with 77% accuracy. Over two decades, salt fields, construction land, and water areas increased due to transformations in saline land and salt flats. The exposed lakes area exhibited a rise followed by a decline, mainly transforming into salt flats. Agricultural land areas slightly increased, influenced by both human activities and climate. Our analysis reveals a strong correlation between salt fields and precipitation, while exposed lakes demonstrate a significant negative correlation with evaporation and temperature, highlighting their vulnerability to climate change. Additionally, human water usage was identified as a significant factor impacting land use change, emphasizing the dual influence of anthropogenic activities and natural factors. This paper addresses the void in the application of Auto ML in salt lake environments and provides valuable insights into the dynamic evolution of land use types in the Qarhan Salt Lake region.

Geochemical Behaviour and Influencing Factors of Salt-Forming Elements in Lithium-Rich Salt Lake Region: A Case Study from the Nalenggele River Basin, Qaidam Basin

Geochemical Behaviour and Influencing Factors of Salt-Forming Elements in Lithium-Rich Salt Lake Region: A Case Study from the Nalenggele River Basin, Qaidam Basin

Advanced risk assessment framework for land subsidence impacts on transmission towers in salt lake region

To ensure the continuous transmission of clean energy for electricity, transmission towers often traverse geologically challenging terrains. This is particularly evident in the Salt Lake region, where the convergence of unique geological attributes and environmental stressors leads to recurrent land subsidence incidents, jeopardizing the integrity of power lines. In light of the prohibitive costs associated with indiscriminate remedial actions, precision in risk assessment and management is imperative to streamline these interventions. The objective of this study is to propose an accurate and effective framework for assessing the risk of land subsidence for power transmission towers. To achieve this, by utilizing the Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technology and cross-validation from field investigations, representative sample disaster datasets of surface deformation points of transmission towers are obtained in the first. Two optimization approaches for susceptibility modeling were employed to further enhance the susceptibility model for land subsidence and obtain high-precision susceptibility results along the transmission towers. Then, combined on-site damage investigation with SBAS-InSAR technology to conduct subsidence vulnerability analysis of transmission towers. Finally, the ultimate outcome of this process was the development of a risk assessment matrix based on spatial probability (susceptibility) and damage scales (vulnerability), aimed at more accurately assessing land subsidence risk. This framework could identify the spatial distribution of subsidence susceptibility in transmission towers exposed to potential damage, which could be followed by a more detailed transmission tower-based vulnerability and risk assessment. The method has been successfully applied in the Salt Lake area, and the susceptibility results based on the Grey Wolf Optimization-Random Forest (GW0-RF) model have shown the best modeling effect, and the area under of receiver operating characteristic curve (AUC) = 0.95. The vulnerability results show that 105 towers have been most severely damaged by land subsidence The risk distribution map shows that the central part of the Salt Lake area is the core zone for future land subsidence risk management. A total of 101 towers are in the high and very high risk level. The insights garnered from this investigation furnish a comprehensive understanding of the risk landscape for transmission towers, underpinning future-focused design, planning, and management strategies.

Changing of mechanical property and bearing capacity of strongly chlorine saline soil under freeze-thaw cycles

Freeze-thaw cycles and compactness are two critical factors that significantly affect the engineering properties and safety of building foundations, especially in seasonally frozen regions. This paper investigated the effects of freeze-thaw cycles on the shear strength of naturally strongly chlorine saline soil with the compactness of 85%, 90% and 95%. Three soil samples with different compactness were made. Size and mass changes were measured and recorded during freeze-thaw cycles. Shear strength under different vertical pressures was determined by direct shear tests, and the cohesion and friction angle were measured and discussed. Microstructure characteristic changes of saline soil samples were observed using scanning electron microscopy under different freeze-thaw cycles. Furthermore, numerical software was used to calculate the subsoil-bearing capacity and settlement of the electric tower foundation in the Qarhan Salt Lake region under different freeze-thaw cycles. Results show that the low-density soil shows thaw settlement deformation, but the high-density soil shows frost-heaving deformation with the increase in freeze-thaw cycles. The shear strength of the soil samples first increases and then decreases with the increase in freeze-thaw cycles. After 30 freeze-thaw cycles, the friction angle of soil samples is 28.3%, 29.2% and 29.6% lower than the soil samples without freeze-thaw cycle, the cohesion of soil samples is 71.4%, 60.1% and 54.4% lower than the samples without freeze-thaw cycle, and the cohesion and friction angle of soil samples with different compactness are close to each other. Microstructural changes indicate that the freeze-thaw cycle leads to the breakage of coarse particles and the aggregation of fine particles. Correspondingly, the structure type of soil changes from a granular stacked structure to a cemented-aggregated system. Besides, the quality loss of soil samples is at about 2% during the freeze-thaw cycles. Results suggest that there may be an optimal compactness between 90 and 95%, on the premise of meeting the design requirements and economic benefits. This study can provide theoretical guidance for foundation engineering constructions in seasonally frozen regions.

Influence of Drying Conditions on the Durability of Concrete Subjected to the Combined Action of Chemical Attack and Freeze-Thaw Cycles.

The durability of concrete is critical for the service life of concrete structures, and it is influenced by various factors. This paper investigates the impact of the relative humidity (RH) of the curing environment on the durability of five different concrete types. The aim is to determine a suitable approach for designing concrete that is well-suited for use in the salt lake region of Inner Mongolia. The concrete types comprise ordinary Portland cement (OPC), high-strength expansive concrete (HSEC), high-strength expansive concrete incorporating silica fume, fly ash, and blast furnace slag (HSEC-SFB), steel fiber-reinforced high-strength expansive concrete (SFRHSEC), and high elastic modulus polyethylene fiber-reinforced high-strength expansive concrete (HFRHSEC). All these concrete types underwent a 180-day curing process at three distinct relative humidities (RH = 30%, 50%, and 95%) before being subjected to freeze-thaw cycles in the Inner Mongolia salt lake brine. The curing environment with a 95% RH is referred to as the standard condition. The experimental results reveal that the durability of OPC and HSEC decreases significantly with increasing relative humidity. In comparison with the control sample cured in 95% RH, the maximum freeze-thaw cycles for concrete cured in lower RHs are only 31% to 76% for OPC and 66% to 77% for HSEC. However, the sensitivity of the durability of HSEC-SFB, SFRHSEC, and HFRHSEC to variations in RH in the curing environment diminishes. In comparison with the corresponding reference value, the maximum freeze-thaw cycles for samples cured in dry conditions increase by 14% to 17% for HSEC-SFB and 21% for SFRHSEC. Specifically, the service life of HFRHSEC cured in a low RH is 25% to 46% higher than the reference value. The durability of HSEC-SFB, SFRHSEC, and HFRHSEC has been proven to be appropriate for structures located in the salt lake region of Inner Mongolia.

Lithium and strontium isotopic systematics in the Nalenggele River catchment of Qaidam basin, China: Quantifying contributions to lithium brines and deciphering lithium behavior in hydrological processes

The salt lakes fed by the Nalenggele River in the Qaidam Basin, located on the northeastern Qinghai Tibetan Plateau (QTP), are major brine lithium reservoirs in China. The quantitative identifications of the Li sources and their dynamic behavior shed light on the formation mechanism of the brine Li deposits in closed-basin of arid regions. This study presents Li and Sr isotope ratios (δ7Li, 87Sr/86Sr) and other hydrogeochemical parameters for river waters, springs, spring river waters, shallow groundwaters, surface brines, and intercrystalline brines around the Nalenggele River Basin (NRB) and its adjacent small watersheds. The results indicate that the Nalenggele River water is a mixing product of hot springs and regional surface meltwater, and the source of dissolved Li in the NRB is mainly supplied by the hot springs. With multi-tracer models, it is confirmed that around 84.9 %−93.4 % of dissolved Li is provided by the Li-rich hot spring waters, which account for only 3–5 % of the total water input. Furthermore, the dissolved Li in the streams of different hydrological regions shows various isotopic fractionation behavior. In general, the lower average δ7Li values (average of +5.6 ‰) with more enriched Li with respect to Na in the waters of the piedmont Gobi region indicates a significant additional input of dissolved Li from bedrock and sediments. The second-stage alluvial fan of the NRB produces 7Li enrichments and Li-depleted waters (compared with Na), which can be explained by the adsorption of clay or Fe (Mn) oxide phases that fractionate Li isotopes. The highest average δ7Li values (+12.76 ‰) are observed when Li is not adsorbed by the scarce fine clastic sediments in the hypersaline environment of the salt lake region. It can be concluded that the continuous halite precipitation during the brine evolution not only causes the abnormal enrichment of Li in the brine (compared with Na) but also continuously sequesters the 6Li from the brines, resulting in a significant 7Li enrichment. Overall, these findings advance the understanding of the lithium sources of Li-rich brines and its enrichment and metallogenic process during water migration in hyper-arid regions and have crucial indicative significance for lithium cycling under a strong evaporation environment.

Damage and Deterioration Model of Basalt Fiber/Magnesium Oxychloride Composites Based on GM(1, 1)-Markov in the Salt Spray Corrosion Environment

This study was designed to solve the problem of magnesium hazards due to potash extraction in the salt lake region. Using basalt fiber (BF) as the reinforcement material and magnesium oxychloride cement (MOC) as the gelling material, a BF/MOC composite material was prepared. Firstly, the effect of BF addition content on the basic mechanical properties of the composites was investigated. Then, through the salt spray corrosion test, the durability damage deterioration evaluation analysis was carried out from both macroscopic and microscopic aspects using mass change, relative dynamic modulus of elasticity (RDME) change, SEM analysis and FT-IR analysis. Finally, a GM(1, 1)-Markov model was established to predict the durability life of composite materials by using durability evaluation indicators. The results show that: when the BF content is 0.10% (by volumetric content), the composites have the best mechanical properties and resistance to salt spray corrosion. However, when the volume of BF content exceeds 0.10%, a large number of magnesium salt crystallization products are observed from the microscopic point of view, and the corrosion of the main strength phase of MOC is more serious. The prediction results of the GM(1, 1)-Markov model are highly identical with the raw data. In addition, using the change of RDME as a predictor, RDME is more sensitive to environmental factor compared to the change of mass. Predictions using the change of RDME as a threshold indicate that MOC-BF0.10 has the longest durability life, which is 836 days. The model is important to promote the application of MOC composites in the salt lake region and to promote the healthy development of green building materials.

Terrible Revolution: Latter-day Saints and the American Apocalypse

Terrible Revolution: Latter-day Saints and the American Apocalypse

Luminescence chronology and environmental implications of palaeolacustrine sediments beneath linear dunes in northern Qarhan Salt Lake region

Luminescence chronology and environmental implications of palaeolacustrine sediments beneath linear dunes in northern Qarhan Salt Lake region

Extraction and analysis of saline soil deformation in the Qarhan Salt Lake region (in Qinghai, China) by the sentinel SBAS-InSAR technique

The instability of saline soil foundation affects the safety of artificial construction, and may cause ground collapse, building destruction and road damage. It is fundamental to reduce the potential engineering geological disasters by exploring the dynamic evolution of saline soil. Most of the previous researches of saline soil were conducted by simulated experiments and traditional geodetic surveying methods. Restricted to the limited sampling points, the spatiotemporal evolution characteristics of saline soil were difficult to find out in a large scale. This paper exploited SBAS-InSAR method to extract the deformation of the Qarhan Salt Lake (in Qinghai, China) section along Qinghai-Tibet railway, based on 119 image data acquired by Sentinel-1A from 2015 to 2020. The results showed that the deformation trends varied frequently in this saline mud flat. Between the adjacent areas with different deformation trends along Qinghai-Tibet railway, discontinuities caused by uplift and subsidence were very obvious. Besides, among the areas with brine exploitation or artificial construction, the maximum subsidence rate reached50 mm/yr, and the maximum cumulative subsidence exceeded 320 mm in the latest 5 years. In the saline mud flat closed to the rivers and lakes, the deformation trend was continuous uplift. Nevertheless, there were obvious seasonal deformation characteristics in those areas far away from the water body. Further analysis found out a sharply subsidence caused by the salt collapsibility appeared in rainy seasons. While an uplift trend induced by the salt swelling or frost heave was remarkable in dry seasons. Subsequently, the relationships were analyzed between the time series deformation and external environmental factors. Furthermore, the deformation mechanism of saline soilin the Qarhan Salt Lake region was interpreted then. In general, this study provides complete spatiotemporal evolution information of saline soil, and demonstrates the deformation characteristics of saline soil in the Qarhan Salt Lake region successfully. Related results would contribute to the safety monitoring for large-scale infrastructure construction in the saline soil areas.

Livelihood security enhancement though innovative water management in dryland India

ABSTRACT Locally nuanced community-based shallow groundwater management interventions have proven important in saline and sodic monsoonal regions. A mixed methods approach characterizes achievement of regeneration of the formerly degraded socio-ecological system of Laporiya village in the semi-arid Salt Lake region of Rajasthan state (India), with a focus on locally adapted chauka systems. Local people are key participants and agents as well as principal beneficiaries of innovative nature-based management interventions. Technological innovations and governance are adapted to environmental processes and local livelihood priorities, resisting imposed engineered solutions. Findings are transferrable to dryland areas facing similar challenges of declining water and livelihood security.

Model efficiency performance assessment through a standard triangular diagram (STD)

Model efficiency performance provides reliable and acceptable criteria by comparing the factual data with the model results based on a set of significant parameters’ comparisons. In this paper, a standard triangular diagram (STD) is proposed for such a goal through the comparisons of arithmetic averages, standard deviations, and serial correlation coefficients ratios. It provides also the comparison among different dimensional units. The application of the STD concept is presented for a set of annual rainfall records at different locations based on monthly hydro-meteorological data (rainfall, potential evaporation, soil moisture, and surface runoff) from Salt Lake (in Turkey) region, monthly flow series from trans-boundary Tigris River and autoregressive moving average, ARIMA, and stochastic model ensemble of simulations.

Brine-freeze-thaw Durability and Crack Density Model of Concrete in Salt Lake Region

The brine-freeze-thaw durability (defined as the durability under freeze-thaw cycles in Qinghai salt lake brine) of concrete (ordinary Portland cement concrete (OPC), high performance concrete (HPC-a), high performance concrete with steel fiber (HPC-b), and high performance concrete with high Young’s modulus polyethylene fiber (HPC-c)) was systematically investigated by the relative dynamic elastic modulus, the relative mass, the appearance, the scanning electron microscopy, and the X-ray diffraction. In addition, the low-temperature physical and chemical corrosion mechanism and a crack density model after the modified relative dynamic elastic modulus being taken into consideration were proposed. The results show that the deterioration of OPC is the severest, followed by HPC-a, HPC-c and HPC-b. The admixture or the fiber is mixed into concrete, which can improve the brine-freeze-thaw durability of concrete. The critical mass growth of the failure of concrete is 3.7%. The cause of the deterioration of concrete under the brine-freeze-thaw cycles is physical and chemical corrosion, not freezing and thawing. The crack density model can effectively describe the deterioration evolution of concrete.

Wintertime spatial distribution of ammonia and its emission sources in the Great Salt Lake region

Abstract. Ammonium-containing aerosols are a major component of wintertime air pollution in many densely populated regions around the world. Especially in mountain basins, the formation of persistent cold-air pools (PCAPs) can enhance particulate matter with diameters less than 2.5 µm (PM2.5) to levels above air quality standards. Under these conditions, PM2.5 in the Great Salt Lake region of northern Utah has been shown to be primarily composed of ammonium nitrate; however, its formation processes and sources of its precursors are not fully understood. Hence, it is key to understanding the emission sources of its gas phase precursor, ammonia (NH3). To investigate the formation of ammonium nitrate, a suite of trace gases and aerosol composition were sampled from the NOAA Twin Otter aircraft during the Utah Winter Fine Particulate Study (UWFPS) in January and February 2017. NH3 was measured using a quantum cascade tunable infrared laser differential absorption spectrometer (QC-TILDAS), while aerosol composition, including particulate ammonium (pNH4), was measured with an aerosol mass spectrometer (AMS). The origin of the sampled air masses was investigated using the Stochastic Time-Inverted Lagrangian Transport (STILT) model and combined with an NH3 emission inventory to obtain model-predicted NHx (=NH3+pNH4) enhancements. Enhancements represent the increase in NH3 mixing ratios within the last 24 h due to emissions within the model footprint. Comparison of these NHx enhancements with measured NHx from the Twin Otter shows that modelled values are a factor of 1.6 to 4.4 lower for the three major valleys in the region. Among these, the underestimation is largest for Cache Valley, an area with intensive agricultural activities. We find that one explanation for the underestimation of wintertime emissions may be the seasonality factors applied to NH3 emissions from livestock. An investigation of inter-valley exchange revealed that transport of NH3 between major valleys was limited and PM2.5 in Salt Lake Valley (the most densely populated area in Utah) was not significantly impacted by NH3 from the agricultural areas in Cache Valley. We found that in Salt Lake Valley around two thirds of NHx originated within the valley, while about 30 % originated from mobile sources and 60 % from area source emissions in the region. For Cache Valley, a large fraction of NOx potentially leading to PM2.5 formation may not be locally emitted but mixed in from other counties.

Comparative analysis of the quality and health-promoting compounds of two-shaped fruits of wild Lycium ruthenicum Murr. from the Qinghai–Tibet Plateau

Lycium ruthenicum Murr. is an econo-ecological tree species that abounds in the Qinghai–Tibet Plateau, which is located in the Chaka Salt Lake region of Qinghai Province, China. This study compared the phenotypes and main inclusions in two-shaped berries (flat peach and sphere types) at different developmental stages of L. ruthenicum Murr. to provide first-hand information for targeted breeding toward higher quality and stronger stress resistance of the fruit. Results showed the distinct advantage of the quality characters of flat peach-type fruits over the sphere-type with regard to the length of bearing shoot, internode, peduncle, single fruit weight, and 100-pod weight. In terms of inclusions, the anthocyanin contents in two-shaped fruits showed no significant difference at S5. Anthocyanin accumulated in the developing fruits, and the amount peaked at S4 and then gradually decreased. The expression profiles of the key genes in anthocyanin biosynthesis were correlated with anthocyanin accumulation during fruit development, and the high expressions of flavonoid 3′,5′-hydroxylase gene and dihydroflavonol 4-reductase gene were found to be the critical factors of specific delphinidin accumulation. Sphere-type mature fruits had considerable higher total polyphenol level than flat peach fruits, but the opposite result was observed for polysaccharides. The contents of Ca, Co, Cr, Cu, K, Li, Mn, P, Ti, V, and Al presented no considerable differences, whereas B, Mg, Na, Si, and Zn exhibited evident advantages in sphere-type fruits. α-Toc was the most abundant component in both fruits and no evident difference in its content was observed. The data on nutritional contents provide a theoretical basis for different breeding goals of L. ruthenicum and its further utilization as health food.

Experimental research on physical properties of saline soil subgrade filler in Chaerhan region.

In order to improve the engineering stability of saline soil of high chloride content in the Chaerhan salt lake region,six typical characteristics saline soil samples were selected,and tests on their primary physical properties(total salt content,specific gravity of soil,liquid limit,plastic limit,maximum dry density,and optimal water content) were conducted.The relationships among them were analyzed,a series of variation laws between salt content and these basic physical parameters were determined,and regression equations were derived.This research can improve future engineering design and construction in saline soils and can also help prevent subgrade filler from undermining subgrade stability and producing disease.

Antagonistic yeasts from a salt-lake region in Egypt: identification of a taxonomically distinct group of phylloplane strains related to Sporisorium.

Non-pathogenic yeasts antagonising microorganisms that cause pre- and postharvest diseases of plants have been found in diverse habitats. Their practical applicability as biocontrol agents (BCAs) depends on the strength of their antagonistic activity and/or spectrum of sensitive target microorganisms. In this study, yeasts were isolated from the phylloplane and fruits of plants growing in the alkaline water lake region Wadi El-Natrun, Egypt, and tested for antifungal and antibacterial activity. All phylloplane yeast isolates belonged to the Basidiomycota and most of them could antagonise at least certain test organisms. One group of isolates showing strong antagonism against almost all fungi and yeasts appears to represent a hitherto undescribed species distantly related to the smut genus Sporisorium. This is the first report of antagonistic activity in Sporisorium. The isolates assigned to Naganishia and Papiliotrema were more effective against bacteria. The broadest range and intensity of antagonism was observed in the fruit-associated strains belonging to the ascomycetous species Wickerhamomyces subpelliculosus. The Wickerhamomyces strains are good broad-spectrum BCA candidates, the Sporisorium strains could be used as efficient antifungal BCAs, whereas the Papiliotrema isolate can be exploited as an antibacterial biocontrol agent.

Effect of boric acid and lithium chloride on magnesium oxysulfate cement

To reduce the production cost of magnesium oxysulfate cement(MOS) in western China and the Salt Lake region, the use of salt lake by-products such as magnesium slag, etc. to prepare raw materials for MOS has become an effective way. However, the raw material of MOS obtained through this route contains some impurities, mainly boron and lithium. Therefore, to study the effect of boron and lithium elements on the performance of MOS, boron acid and lithium chloride were used to study the effect of boron and lithium on the setting time and compressive strength of MOS. And the influence of boric acid and lithium chloride on the hydration products and microstructure of MOS was discussed. The results show:Additives (boric acid and lithium chloride) did not change the MOS hydration phase and the micro-morphology, but delayed the MOS hydration process and increased MOS initial setting and final setting time, resulting in a decrease of the MOS’s early compressive strength, but had no effect on the MOS’s later compressive strength.

Geochronology and mineral composition of the pleistocene sediments in Xitaijinair Salt Lake region, Qaidam Basin: Preliminary results

Xitaijinair (XT) Salt Lake, located in the western Qaidam Basin, is significant for reconstructing the evolution of inland drying climate. However, the chronological and mineralogical records from this lake are rare. This study investigated the chronology (accelerator mass spectrometry (AMS) 14C ages and optically stimulated luminescence (OSL) ages) and mineral compositions of sediment in the 240-cm-deep XT Section of the Xitaijinair Salt Lake region. The conclusions are drawn as follows: (1) Nine AMS 14C ages, ranging between 33 and 40 cal ka BP, are obviously younger than the two OSL ages (57.9 and 69.1 ka). The 14C ages probably reflect contamination with modern carbon. (2) Both 14C and OSL ages indicate that the surface of Xitaijinair Salt Lake region has suffered erosion. (3) The sediments of XT Section are composed of silicates (quartz, muscovite, clinochlore and albite), carbonates (calcite, dolomite, and ankertie), halite and gypsum.