scholarly journals Artificial biocrust establishment on materials of potash tailings piles along a salinity gradient

2021 ◽  
Author(s):  
V. Sommer ◽  
A. Palm ◽  
A. Schink ◽  
P. Leinweber ◽  
N. Gose ◽  
...  
Keyword(s):  
Sodium Alginate ◽  
Soil Stabilization ◽  
Salinity Gradient ◽  
Bare Soil ◽  
Photosynthetic Performance ◽  
Dune Sand ◽  
Future Studies ◽  
Sand Surface ◽  
Salt Gradient ◽  
Hydrological Cycles

Abstract Biocrust communities provide a pallet of ecosystem services, such as soil stabilization, altering of hydrological cycles and primary production, and often are the first colonizers of unvegetated surfaces during succession. Therefore, artificially establishing biocrusts can improve soil properties, for example, by stabilizing bare soil surfaces against erosion or by accumulating nutrients. In this study, the establishment of artificial biocrusts was tested for the restoration of potash tailings piles that result from potash fertilizer production and mostly consist of NaCl. A biocrust cover as primary vegetation could decrease the saline seepage waters by trapping rainwaters, thereby reducing the environmental pollution. In a laboratory experiment, we created a salt gradient by mixing the tailings materials with non-saline dune sand. Surface material of the abandoned potash tailings pile Neuhof-Ellers (NE) and material of the Infiltration Hampering Stratum (IHS) were tested, along with a treatment with bone charplus (BCplus) and sodium alginate. A mixture of 50% (w/w) IHS and dune sand was most successful for the establishment of green biocrust microalgae, based on increased biomass and photosynthetic performance. The chlorophyll a content was negatively correlated with the electrical conductivity (EC), and was significantly increased in the BCplus and sodium alginate treatment, while biocrusts failed to establish on pure tailings piles substrates. The limit of the substrates EC for biocrust establishment was 35 mS cm−1. This limit provides a baseline for future studies that should use BCplus and sodium alginate to increase the success of biocrust establishment on potash tailings piles.

scholarly journals Compaction and Collapse Characteristics of Dune Sand Stabilized with Lime-Silica Fume Mix

2016 ◽  
Vol 20 (2) ◽  
pp. 1 ◽  
Author(s):  
Mohammed Y. Fattah ◽  
Hasan H. Joni ◽  
Ahmed S. A. Al-Dulaimy
Keyword(s):  
Silica Fume ◽  
Soil Stabilization ◽  
Ground Improvement ◽  
Construction Materials ◽  
California Bearing Ratio ◽  
Dune Sand ◽  
Dune Sands ◽  
Maximum Percentage ◽  
Collapse Characteristics ◽  
Sand Stabilized

The purpose of this research is to assess the suitability of dune sands as construction materials. Moreover, such a goal is considered beneficial in determining appropriate methods for soil stabilization or ground improvement and to assessing the suitability of dune sands as subgrade layer for carrying roads and rail foundation. Dune sand samples were collected from a region in Baiji area in Salah-Aldeen governorate, North of Iraq. A grey-colored densified silica fume (SF) and lime (L) are used. Three percentages are used for lime (3%, 6%, and 9%), and four rates are used for silica fume (3%, 6%, 9% and 12%) and the maximum percentage of silica fume is mixed with the proportions of lime. Unsoaked California Bearing Ratio (CBR) on compacted dune sands treated dune sands with L-SF by mixing and cured for one day. The increasing in CBR ranged between 443 – 707% at 2.54 mm penetration and 345 – 410% at 5.08 mm penetration.   ResumenEl propósito de esta investigación es evaluar el uso de arena de dunas como materiales de construcción. Además, este objetivo permite determinar los métodos apropiados para la estabilización del suelo, el mejoramiento del terreno y la evaluación de pertinencia de la arena de dunas en capas subbase para carreteras y cimientos férreos. Se recolectaron muestras de arena de dunas en el área de Baiji, del comisionado Salah-Aldeen, al norte de Irak. Se utilizó vapor de óxido de silicio (SF, en inglés), grisáceo y densificado, y óxido de calcio (L). Se utilizaron tres porcentajes para el óxido de calcio (3 %, 6 % y 9 %), y cuatro para el óxido de silicio (3 %, 6 %,  9% y 12%) y el máximo porcentaje del óxido de silicio se mezcló con las proporciones de óxido de calcio. Se realizó en seco el Ensayo de Relación de Soporte de California (del inglés California Bearing Ratio, CBR) en arena de dunas compactada y tratada con la mezcla L-SF curada durante un día. El incremento en el ensayo CBR osciló entre 443-707 % en la penetración de 2.5 mm y 345-410 % en la penetración de 5.08 mm.

Experimental investigation on a novel composite salt-gradient solar pond with East-West side reflector

2021 ◽  
pp. 1-31
Author(s):  
Dhandapani Sathish ◽  
Selvaraj Jegadheeswaran
Keyword(s):  
Thermal Energy ◽  
Salinity Gradient ◽  
The Novel ◽  
Solar Pond ◽  
Triple Layer ◽  
Solar Radiation Intensity ◽  
Salt Gradient ◽  
Cost Efficient ◽  
East West ◽  
Diurnal Period

Abstract A salt gradient solar pond acts as an eco-friendly and cost-efficient device for storing thermal energy storage. It is crucial to enrich the efficiency of the salt gradient solar pond to boost its thermal energy storage.This current study investigates the hexagonal composite salinity gradient solar pond (HCSGSP) augmented with a dual inclined reflector and triple-layer transparent cover. A micro solar pond having a hexagonal cross-section was fabricated and experimented at Coimbatore, India having a datum and surface area of 1 m and 0.679 m2 respectively. The novel usage of composite salt (Sodium chloride 30%, Magnesium chloride 10%, and Potassium chloride 60%) led to the enhancement of the daily average ponds' temperature. The pond's upper portion was packed with a triple layer glazed cover which shows an uplift of thermal energy and the pond is provided with inclined reflectors made of plywood fixed with mirrors on the east west direction. The purpose of the mirrors is to increase the solar radiation intensity during the diurnal period and also it acts as an insulator which minimizes the heat losses during the nocturnal period.The maximum thermal efficiencies of the top convective, middle non-convective, and bottom convective layers of reformed solar pond were measured to be 23.44%, 30.68%, and 35.63% respectively whereas they were 1.32%, 12.32%, and 23.44% respectively in case of conventional pond.

The Influence of Height of LCZ on the Salinity Diffusion of Solar Pond

2013 ◽  
Vol 448-453 ◽  
pp. 1521-1524
Author(s):  
Chun Juan Gao ◽  
Qi Zhang ◽  
Hai Hong Wu ◽  
Liang Wang ◽  
Xi Ping Huang
Keyword(s):  
Solar Energy ◽  
Fresh Water ◽  
Salt Water ◽  
Salinity Gradient ◽  
Good Method ◽  
Convective Zone ◽  
Solar Ponds ◽  
Solar Pond ◽  
Salt Gradient ◽  
And Diffusion

The solar ponds with a surface of 0.3m2were filled with different concentration salt water and fresh water. The three layer’s structure of solar ponds was formed in the laboratory ponds by using the salinity redistribution. The performance and diffusion of salinity were xperimentally in the solar pond. The measurements were taken and recorded daily at various locations in the salt-gradient solar pond during a period of 30 days of experimentation. The experimental results showed that the salinity gradient layer can sustain a longer time when the lower convective zone is thicker, which is benefit to store solar energy. Therefore, properly increasing the height of LCZ is a good method to enhance the solar pond performance.

Experimental Investigations on Salt Gradient Solar Pond with Additional Non-Convective Zone for Improved Thermal Performance and Stability

2021 ◽  
Vol 43 ◽  
pp. 59-71
Author(s):  
Devendra B. Sadaphale ◽  
S.P. Shekhawat ◽  
Vijay R. Diware
Keyword(s):  
Heat Storage ◽  
Salinity Gradient ◽  
Convective Zone ◽  
Salt Flux ◽  
Maximum Temperature ◽  
Experimental Investigations ◽  
Thickness Variation ◽  
Salty Water ◽  
Solar Pond ◽  
Salt Gradient

Salt gradient solar ponds are to be designed for thermal efficiency and salinity profile stability. As the salt flux moves upward in the pond, the gradient gets destabilized. This is counteracted by intrusion of salt at different levels as and when required. The density of salt is highest at the bottom and minimum at the top. Hence the destabilization effect is more at top that is at the interface of upper convective zone and non-convective zone (NCZ). In order to keep the interface stable, it is desirable to provide a higher slope of salt gradient near it. However, throughout the non-convective zone, it is not feasible to provide higher slope due to solubility limitations. Hence Husain et al (2012) to divide the NCZ into two parts. The top few centimeters may be given a higher slope and the rest of the zone may be given mild slope as usual. Husain et al (2012) have given analysis for the same and found it to be feasible. However, the experimental feasibility of the same needs to be verified. The present work has done an attempt for the same. In this study, an insulated solar pond with a surface area of 1.40 m2and a depth of 1.14 m is built at the SSBT’s College of Engineering and Technology, Jalgaon in the Maharashtra State (India). The three salty water zones (upper convective, non-convective and heat storage) were formed by filling the pond with salty water of various densities. 6 Thermocouples (type Pt100A) (C+0.2%) were used to measure the temperature profile within the pond. A maximum temperature of 47°C was recorded in the heat storage zone in time span considered for study. The results obtained from experimentation is verified with the concept suggested by Hussain et al (2012) it has been found that they are in a good agreement. The influence of varying the thicknesses of the zones present in a salinity gradient solar pond on the temperatures of the upper convective zone (UCZ) and the lower convective zone (LCZ) is investigated. Also, it is found that by adding the additional non convective zone of 50 mm thickness above the UCZ the heat collection capacity of the LCZ is increased noticeably. The study finds that thickness variation of the zones within the pond is a practical feasibility. The system worked for the entire experimental duration effectively without failure.

Strengthening of Dune Sand with Sodium Alginate Biopolymer

2019 ◽  
Author(s):  
Hadi Fatehi ◽  
Maysam Bahmani ◽  
Ali Noorzad
Keyword(s):  
Sodium Alginate ◽  
Dune Sand

scholarly journals A Prototype of Salt Gradient Solar Pond as Alternative Energy Source for Coastal Communities in Bengkulu

2019 ◽  
Vol 2 (2) ◽  
pp. 25-27
Author(s):  
Afdhal Kuniawan Mainil
Keyword(s):  
Alternative Energy ◽  
Saline Solution ◽  
Salt Water ◽  
Salinity Gradient ◽  
Maximum Temperature ◽  
Average Temperature ◽  
Solar Pond ◽  
Storage Zone ◽  
Salt Gradient ◽  
Further Development

One of the developing technologies of renewable energy is the Salt Gradient Solar Pond (SGSP). SGSP utilize solar energy by storing its thermal energy in a pond of saline solution. Bengkulu Province has a high intensity of sunlight and a long coastline with an abundance of salt water. Therefore, it is a very suitable location for further development of SGSP technology. The design of SGSP prototype had been carried out by using a 1 m3 cylinder as the saline solution pond. The density and temperature of the solution were measured at 11 points from the bottom to the top of the cylinder. The results show that the keeper of the pond, the more density of the solution, in which the highest solution density was at the bottom of the pond, i.e., 1.206 gr/cm3. The average temperature of the solution was 44.2°C. The maximum temperature, which was 48.7 °C, was observed around the storage zone, about 0.3 m from the pond‘s bottom. The results of the measurements of salinity gradient and temperatures show that this prototype of SGSP is appropriate to be used for storing heat around the storage zone.

The behaviour of a stable salinity gradient heated from below

1968 ◽  
Vol 33 (1) ◽  
pp. 183-200 ◽  
Author(s):  
J. S. Turner
Keyword(s):  
Boundary Layer ◽  
Stability Criterion ◽  
Salinity Gradient ◽  
Bottom Layer ◽  
Diffusive Boundary Layer ◽  
Advancing Front ◽  
Steady Rate ◽  
Diffusive Boundary ◽  
Salt Gradient ◽  
The Given

The motions resulting when a linear, stable salt gradient is heated uniformly and at a steady rate from below are investigated theoretically and by laboratory experiment. A convecting, growing layer is first formed whose depth, temperature and salinity differences from the fluid above, are all increasing as t½. The way in which these quantities depend on the salinity gradient and heating rate is also predicted, and verified experimentally. A stability criterion is then developed which describes the breakdown of the diffusive boundary layer ahead of the advancing front, and leads to an expression for the thickness of the bottom layer when a second layer forms above it. The predicted form of dependence of layer thickness on the given parameters is again borne out by the experiments.

An Early Developmental Marker for Radial Glia in Rat Spinal Cord

1996 ◽  
Vol 54 ◽  
pp. 36-37
Author(s):  
V. Kriho ◽  
H.-Y. Yang ◽  
C.-M. Lue ◽  
N. Lieska ◽  
G. D. Pappas
Keyword(s):  
Spinal Cord ◽  
Intermediate Filament ◽  
Radial Glia ◽  
Rat Spinal Cord ◽  
Future Studies ◽  
Spinal Cord Development ◽  
Median Septum ◽  
Differentiation Marker ◽  
Early Developmental ◽  
Developing Rat

Radial glia have been classically defined as those early glial cells that radially span their thin processes from the ventricular to the pial surfaces in the developing central nervous system. These radial glia constitute a transient cell population, disappearing, for the most part, by the end of the period of neuronal migration. Traditionally, it has been difficult to definitively identify these cells because the principal criteria available were morphologic only.Using immunofluorescence microscopy, we have previously defined a phenotype for radial glia in rat spinal cord based upon the sequential expression of vimentin, glial fibrillary acidic protein and an intermediate filament-associated protein, IFAP-70/280kD. We report here the application of another intermediate filament-associated protein, IFAP-300kD, originally identified in BHK-21 cells, to the immunofluorescence study of radial glia in the developing rat spinal cord.Results showed that IFAP-300kD appeared very early in rat spinal cord development. In fact by embryonic day 13, IFAP-300kD immunoreactivity was already at its peak and was observed in most of the radial glia which span the spinal cord from the ventricular to the subpial surfaces (Fig. 1). Interestingly, from this time, IFAP-300kD immunoreactivity diminished rapidly in a dorsal to ventral manner, so that by embryonic day 16 it was detectable only in the maturing macroglial cells in the marginal zone of the spinal cord and the dorsal median septum (Fig. 2). By birth, the spinal cord was essentially immuno-negative for this IFAP. Thus, IFAP-300kD appears to be another differentiation marker available for future studies of gliogenesis, especially for the early stages of radial glia differentiation.

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