Search results for: acid soil

Authors: F. Adjel, S. Almi, D. Barkat

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The synergistic solvent extraction of cobalt (II) from 0.33 mol dm-3 Na2SO4 aqueous solutions with capric acid (HL) in the absence and presence of tri-n-octylphosphine oxide (TOPO) in chloroform at 25°C, has been studied. The extracted species when the capric acid compound was used alone, is CoL2(HL)2. In the presence of TOPO, a remarkable enhancement on the extraction of nickel (II) with 0.02 mol dm-3 capric acid was observed upon the addition of 0.0025 to 0.01 mol dm-3 TOPO in chloroform. From an synergistic extraction- equilibrium study, the synergistic enhancement was ascribed to the adduct formation CoL2(HL)2 n(TOPO). The TOPO-HL interaction strongly influences the synergistic extraction efficiency. The synergistic extraction stoichiometry of cobalt (II) with capric acid and TOPO is studied with the methods of slope analysis. The equilibrium constants were determined.

Keywords: solvent extraction, cobalt (II), capric acid, TOPO, synergism

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Authors: Malika Foudia, Larbi Zerroual

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The objective of this work is to improve the electrical proprieties of lead-acid battery with the addition of additives in electrolyte and in the cured plates before oxidation. The results showed that the addition of surfactant in sulfuric acid and 3% mineral additive in the cured plates change the morphology and the crystallite size of PAM after oxidation. The discharge capacity increases with the decrease of the crystallite size and the resistance of the active mass. This shows that the addition of mineral additive and the surfactant additive to the PAM, the electrical performance and the cycle life of lead- acid battery are significantly increases.

Keywords: lead-acid battery, additives, positive plate, impedance (EIS).

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Authors: F. Adjel, C. Bensmail, S. Almi, D. Barkat

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The synergistic solvent extraction of cobalt (II) from 0.33 mol dm^-3 Na2SO4 aqueous solutions with capric acid (HL) in the absence and presence of methyl isobutyl cétone (MIBK) in chloroform at 25°C, has been studied. The extracted species when the capric acid compound was used alone, is CoL2(HL)2. In the presence of MIBK, a remarkable enhancement on the extraction of nickel (II) with 0.02 mol dm^-3 capric acid was observed upon the addition of 0.0025 to 0.01 mol dm^-3 MIBK in chloroform. From a synergistic extraction-equilibrium study, the synergistic enhancement was ascribed to the adduct formation CoL2(HL)2 n(MIBK). The MIBK-HL interaction strongly influences the synergistic extraction efficiency. The synergistic extraction stoichiometry of cobalt (II) with capric acid and MIBK is studied with the methods of slope analysis. The equilibrium constants were determined.

Keywords: solvent extraction, cobalt (II), capric acid, MIBK, synergism

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Authors: Mohammad Khattak, Bikash Adhikari, Sambodh Adhikari

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This research deals with the physical, microstructural, mechanical, and shrinkage characteristics of flyash-based soil-geopolymer mixtures. Medium and high plastic soils were obtained from local construction projects. Class F flyash was used with a mixture of sodium silicate and sodium hydroxide solution to develop soil-geopolymer mixtures. Several mixtures were compacted, cured at different curing conditions, and tested for unconfined compressive strength (UCS), linear shrinkage, and observed under scanning electron microscopy (SEM). The results of the study demonstrated that the soil-geopolymer mixtures fulfilled the UCS criteria of cement treated design (CTD) and cement stabilized design (CSD) as recommended by the department of transportation for pavement base and subbase layers. It was found that soil-geopolymer demonstrated either similar or better UCS and shrinkage characteristics relative to conventional soil-cement mixtures. The SEM analysis revealed that microstructure of soil-geopolymer mixtures exhibited development and steady growth of geopolymerization during the curing period. Based on mechanical, shrinkage, and microstructural characteristics it was suggested that the soil-geopolymer mixtures, has an immense potential to be used as pavement subgrade, subbase, and base layers.

Keywords: soil-geopolymer, pavement base, soil stabilization, unconfined compressive strength, shrinkage, microstructure, and morphology

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Authors: Tatiana V. Raudina, Sergey P. Kulizhskiy

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A large part of Russia is located in permafrost areas. These areas are widely used because there are concentrated valuable natural resources. Therefore to explore of cryosols it is important due to the significant increase of anthropogenic stress as well as the problem of global climate change. In the north of Western Siberia permafrost phenomena is widespread. Permafrost as a factor of soil formation and cryogenesis as a process have a great impact on the soil formation of these areas. Based on the research results of permafrost-affected soils tundra landscapes formed in the central part of the Tazovskiy Peninsula in cryogenic conditions, data were obtained which characterize the morphological features of soils. The specificity of soil cover distribution and manifestation of soil-forming processes within the study area are noted. Permafrost features such as frost cracking, cryoturbation, thixotropy, movement of humus are formed. The formation of these features is increased with the development of the territory. As a consequence, there is a change in the components of the environment and the destruction of the soil cover.

Keywords: gleyed and nongleyed soils, permafrost, soil cryogenesis (pedocryogenesis), soil-forming macroprocesses

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Authors: Qasar Saleem

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The aim of this project was to synthesize and analyze Polylactic acid-grafted TiO2 nanocomposite. When dispersed at the nanoscale TiO2 can behave as see through transparent UV filters and thermomechanical materials. The synthesis plan involved three stages. First, dispersion of TiO2 white powder in water/ethanol solvent system. Second grafting TiO2 surface by oligomers of lactic acid aimed at changing its surface features. Third polymerization of lactic acid monomer with grafted TiO2 in the presence of anhydrous stannous chloride as a catalyst. Polylactic acid grafted-TiO2 nanocomposite was synthesized by melt polycondensation in situ of lactic acid onto titanium oxide (TiO2) nanoparticles surface. The product was characterized by TGA, DSC, FTIR, and UV analysis and degradation observation. An idea regarding bonds between the grafting polymer and surface modified titanium oxide nanoparticles. Characteristics peaks of Ti–carbonyl bond, the related intensities of the Fourier transmission absorption peaks of graft composite, the melt and decomposition behavior stages of Polylactic acid-grafted TiO2 nanocomposite convinced that oligomers of polylactic acid were chemically bonded on the surface of TiO2 nanoparticles. Through grafting polylactic acid, the Polylactic acid grafted -TiO2 sample shown good absorption in UV region and degradation behavior under normal atmospheric conditions. Regaining transparency of degraded white opaque Polylactic acid-grafted TiO2 nanocomposite on heating was another character. Polylactic acid-grafted TiO2 nanocomposite will be a potential candidate in future for biomedical, UV shielding and environment friendly material.

Keywords: condensation, nanocomposites, oligomers, polylactic

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Authors: Sayantani Neogi, Sean Taylor, Julia Budka

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This paper presents the results of the investigations of soil/sediment sequences associated with the New Kingdom town at Sai Island, Sudan. During the course of this study, geoarchaeological surveys have been undertaken in the vicinity of this Pharaonic town within the island and the soil block samples for soil micromorphological analysis were accordingly collected. The intention was to better understand the archaeological site in its environmental context and the nature of the land surface prior to the establishment of the settlement. Soil micromorphology, a very powerful geoarchaeological methodology, is concerned with the description, measurement and interpretation of soil components and pedological features at a microscopic scale. Since soil profiles themselves are archives of their own history, soil micromorphology investigates the environmental and cultural signatures preserved within buried soils and sediments. A study of the thin sections from these soils/sediments has been able to provide robust data for providing interesting insights into the various nuances of this site, for example, the nature of the topography and existent environmental condition during the time of Pharaonic site establishment. These geoarchaeological evaluations have indicated that there is a varied hidden landscape context for this pharaonic settlement, which indicates a symbiotic relationship with the Nilotic environmental system.

Keywords: geoarchaeology, New Kingdom, Nilotic environment, soil micromorphology

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Authors: U. A. Asli, H. Hamid, Z. A. Zakaria, A. N. Sadikin, R. Rasit

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This study investigated the effect of a dilute acid, lime and ammonia aqueous pretreatment on the fermentable sugars conversion from empty fruit bunch (EFB) biomass. The dilute acid treatment was carried out in an autoclave, at 121ºC with 4 % of sulphuric acid. In the lime pretreatment, 3 wt % of calcium hydroxide was used, whereas the third method was done by soaking EFB with 28 % ammonia solution. Then the EFB biomass was subjected to a two-stage-acid hydrolysis process. Subsequently, the hydrolysate was fermented by using instant baker’s yeast to produce bioethanol. The highest glucose yield was 890 mg/g of biomass, obtained from the sample which underwent lime pretreatment. The highest bioethanol yield of 6.1mg/g of glucose was achieved from acid pretreatment. This showed that the acid pretreatment gave the most fermentable sugars compared to the other two pretreatments.

Keywords: bioethanol, biomass, empty fruit bunch (EFB), fermentable sugars

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Authors: Nwanneka Mmonwuba

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Solid waste disposal to the environment was investigated by analyzing the quality characteristics of waste, air quality, and heavy metal concentration in the soil. The characteristics of waste were analyzed by enumerating the number of houses, hostels, hotels, markets, schools, and industries with the type of waste being discharged or deposited into the dump site. The percentage of waste was estimated with organic ranking first for both wet and dry seasons, 54% and 44%, respectively. The ambient air quality was analyzed using the crown gas monitor analyzer. The analysis showed that the mean concentration of NO₂, SO₂, and Co is 0.74, 0.37, and 47.35 ppm for the wet season and 0.47, 0.35, and 37.65 ppm for the dry season, respectively, and do not conform with the USEPA standard. The chemical analysis of the groundwater sample indicates alkalinity ranging from 7.38 to 9.11. the heavy metals concentration in the soil of cadmium, iron, copper, calcium, and potassium with 0.053, 0.722, 0227, 21.3, and 9.019, respectively, obtained from 0.3 m at the subsurface failed to conform to the NRC (2013) standard. Iron consent in the soil can be corrected using ascorbic acid and soda ash. The permanent reduction of effects is to try relocating people who live very close to the dumpsite, or the dumpsite should be sited elsewhere and replaced with a sanitary landfill.

Keywords: solid waste, groundwater, disposal, dumpsite

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Authors: Seyed Abolhasan Naeini, Hamidreza Rahmani

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Laboratory consolidated undrained triaxial (CU) tests were carried out to study the strength behavior of silty soil reinforced with randomly plastic waste bottle chips. Specimens mixed with plastic waste chips in triaxial compression tests with 0.25, 0.50, 0.75, 1.0, and 1.25% by dry weight of soil and tree different length including 4, 8, and 12 mm. In all of the samples, the width and thickness of plastic chips were kept constant. According to the results, the amount and size of plastic waste bottle chips played an important role in the increasing of the strength parameters of reinforced silt compared to the pure soil. Because of good results, the suggested method of soil improvement can be used in many engineering problems such as increasing the bearing capacity and settlement reduction in foundations.

Keywords: reinforcement, silt, soil improvement, triaxial test, waste bottle chips

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Authors: A. U. Adamu, Hamisu Abdu, A. A. Saidu

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The enzymatic synthesis of 3-O-β-D-glucopyranoside-betulinic acid using Novozyme-435 as a catalyst was studied. The effect of various parameters such as substrate molar ratio, reaction temperature, reaction time, re-used enzymes and amount of enzymes were investigated. The optimum rection conditions for the enzymatic glycosidation of betulinic acid in an organic solvent using Novozym-435 was found to be at 1:1.2 substrate molar ratio, 55oC, 24 h and 180 mg of enzymes with percentage conversion of 88.69 %.

Keywords: betulinic acid, glycosidation, novozyme-435, optimization

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Authors: Irit Rutman Halili, Tehila Zvulun, Natali Elgabsi, Revaya Cohen, Shlomo Sarig

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Active sand dunes (ASD) may cause significant damage to field crops and livelihood, and therefore, it is necessary to find a treatment that would enhance ADS soil stability. Biological soil crusts (biocrusts) contain microorganisms on the soil surface. Metabolic polysaccharides secreted by biocrust cyanobacteria glue the soil particles into aggregates, thereby stabilizing the soil surface. Filter cake powder (FCP) is a waste by-product in the final stages of the production of sugar from sugarcane, and its disposal causes significant environmental pollution. FCP contains high concentrations of polysaccharides and has recently been shown to be soil stability enhancing agent in ASD. It has been reported that adding FCP to the ASD soil surface by dispersal significantly increases the level of penetration resistance of soil biocrust (PRSB) nine weeks after a single treatment. However, it was not known whether a similar effect could be obtained by administering the FCP in liquid form by means of spraying. It has now been found that spraying a water solution of FCP onto the ASD soil surface significantly increased the level of penetration resistance of soil biocrust (PRSB) three weeks after a single treatment. These results suggest that FCP spraying can be used as a short-term soil stability-enhancing agent for ASD, while administration by dispersal might be more efficient over the long term. Finally, an additional benefit of using FCP as a soil stabilizer, either by dispersal or by spraying, is the reduction in environmental pollution that would otherwise result from the disposal of FCP solid waste.

Keywords: active sand dunes, filter cake powder, biological soil crusts, penetration resistance of soil biocrust

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Authors: Zhaofeng Li, Jun Kang Chow, Yu-Hsing Wang

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This paper attempts to bridge the soil properties and the mechanical response of soil in the discrete element method (DEM) simulation. The artificial neural network (ANN) was therefore adopted, aiming to reproduce the stress-strain-volumetric response when soil properties are given. 31 biaxial shearing tests with varying soil parameters (e.g., initial void ratio and interparticle friction coefficient) were generated using the DEM simulations. Based on these 45 sets of training data, a three-layer neural network was established which can output the entire stress-strain-volumetric curve during the shearing process from the input soil parameters. Beyond the training data, 2 additional sets of data were generated to examine the validity of the network, and the stress-strain-volumetric curves for both cases were well reproduced using this network. Overall, the ANN was found promising in predicting the soil behavior and reducing repetitive simulation work.

Keywords: artificial neural network, discrete element method, soil properties, stress-strain-volumetric response

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Authors: M. Cortés, E. Vera, O. Rojas

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The research studies of the kinetics of the corrosion process that attacks concrete and occurs within sewerage systems agree on the amount of variables that interfere in the process. This study aims to check the impact of the pH levels of the corrosive environment and the concrete surface, the concentrations of chemical sulfuric acid, and in turn, measure the resistance of concrete to this attack under controlled laboratory conditions; it also aims to contribute to the development of further research related to the topic, in order to compare the impact of biogenic sulfuric acid and chemical sulfuric acid involvement on concrete structures, especially in scenarios such as sewerage systems.

Keywords: acid sulfuric, concrete, corrosion, biogenic

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Authors: Yasmeen Saleem, Pedro Berliner, Nurit Agam

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The most severe limitation for plant production in arid areas is water. Rainfall events are rare but can have pulses of high intensity. As a result, crusts are formed, which decreases infiltration into the soil, and results additionally in erosive losses of soil. Direct evaporation of water from the wetted soil can account for large fractions of the water stored in the soil. Different kinds of mulches have been used to decrease the loss of water in arid and semi-arid region. This study aims to evaluate the effect of polystyrene styrofoam pellets mulch on soil infiltration, runoff, and evaporation as a more efficient and economically viable mulch alternative. Polystyrene styrofoam pellets of two sizes (0.5 and 1 cm diameter) will be placed on top of the soil in two mulch layer depths (1 and 2 cm), in addition to the non-mulched treatment. The rainfall simulator will be used as an artificial source of rain. The preliminary results in the prototype experiment indicate that polystyrene styrofoam pellets decreased runoff, increased soil-water infiltration. We are still testing the effect of these pellets on decreasing the soil-water evaporation.

Keywords: synthetic mulch, runoff, evaporation, infiltration

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Authors: Ayuko Itsuki, Sachiyo Aburatani

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Soil neutral sugar contents in Kasuga-yama Hill Primeval Forest (Nara, Japan) were examined using the Waksman’s approximation analysis to clarify relations with the neutral sugar constituted the soil organic matter and the microbial biomass. Samples were selected from the soil surrounding laurel-leaved (BB-1) and Carpinus japonica (BB-2) trees for analysis. The water and HCl soluble neutral sugars increased microbial biomass of the laurel-leaved forest soil. Arabinose, xylose, and galactose of the HCl soluble fraction were used immediately in comparison with other neutral sugars. Rhamnose, glucose, and fructose of the HCl soluble fraction were re-composed by the microbes.

Keywords: forest soil, neutral sugaras, soil organic matter, Waksman’s approximation analysis

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Authors: M. A. Stoian, D. M. Cocarta, A. Badea

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The main sources of soil pollution due to petroleum contaminants are industrial processes involve crude oil. Soil polluted with crude oil is toxic for plants, animals, and humans. Human exposure to the contaminated soil occurs through different exposure pathways: Soil ingestion, diet, inhalation, and dermal contact. The present study research is focused on soil contamination with heavy metals as a consequence of soil pollution with petroleum products. Human exposure pathways considered are: Accidentally ingestion of contaminated soil and dermal contact. The purpose of the paper is to identify the human health risk (carcinogenic risk) from soil contaminated with heavy metals. The human exposure and risk were evaluated for five contaminants of concern of the eleven which were identified in soil. Two soil samples were collected from a bioremediation platform from Muntenia Region of Romania. The soil deposited on the bioremediation platform was contaminated through extraction and oil processing. For the research work, two average soil samples from two different plots were analyzed: The first one was slightly contaminated with petroleum products (Total Petroleum Hydrocarbons (TPH) in soil was 1420 mg/kg_d.w.), while the second one was highly contaminated (TPH in soil was 24306 mg/kg_d.w.). In order to evaluate risks posed by heavy metals due soil pollution with petroleum products, five metals known as carcinogenic were investigated: Arsenic (As), Cadmium (Cd), Chromium^VI (Cr^VI), Nickel (Ni), and Lead (Pb). Results of the chemical analysis performed on samples collected from the contaminated soil evidence soil contamination with heavy metals as following: As in Site 1 = 6.96 mg/kg_d.w; As in Site 2 = 11.62 mg/kg_d.w, Cd in Site 1 = 0.9 mg/kg_d.w; Cd in Site 2 = 1 mg/kg_d.w; Cr^VI was 0.1 mg/kg_d.w for both sites; Ni in Site 1 = 37.00 mg/kg_d.w; Ni in Site 2 = 42.46 mg/kg_d.w; Pb in Site 1 = 34.67 mg/kg_d.w; Pb in Site 2 = 120.44 mg/kg_d.w. The concentrations for these metals exceed the normal values established in the Romanian regulation, but are smaller than the alert level for a less sensitive use of soil (industrial). Although, the concentrations do not exceed the thresholds, the next step was to assess the human health risk posed by soil contamination with these heavy metals. Results for risk were compared with the acceptable one (10^-6, according to World Human Organization). As, expected, the highest risk was identified for the soil with a higher degree of contamination: Individual Risk (IR) was 1.11×10^-5 compared with 8.61×10^-6. 

Keywords: carcinogenic risk, heavy metals, human health risk assessment, soil pollution

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Authors: P. Defossez, J. M. Bonnefond, D. Garrigou, P. Trichet, F. Danjon

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Windstorm damage to European forests has ecological, social and economic consequences of major importance. Most trees during storms are uprooted. While a large amount of work has been done over the last decade on understanding the aerial tree response to turbulent wind flow, much less is known about the root-soil interface, and the impact of soil moisture and root-soil system fatiguing on tree uprooting. Anchorage strength is expected to be reduced by water-logging and heavy rain during storms due to soil strength decrease with soil water content. Our paper is focused on the maritime pine cultivated on sandy soil, as a representative species of the Forêt des Landes, the largest cultivated forest in Europe. This study aims at providing knowledge on the effects of soil saturation on root anchorage. Pulling experiments on trees were performed to characterize the resistance to wind by measuring the critical bending moment (Mc). Pulling tests were performed on 12 maritime pines of 13-years old for two unsaturated soil conditions that represent the soil conditions expected in winter when wind storms occur in France (w=11.46 to 23.34 % gg⁻¹). A magnetic field digitizing technique was used to characterize the three-dimensional architecture of root systems. The soil mechanical properties as function of soil water content were characterized by laboratory mechanical measurements as function of soil water content and soil porosity on remolded samples using direct shear tests at low confining pressure ( < 15 kPa). Remarkably Mc did not depend on w but mainly on the root system morphology. We suggested that the importance of soil water conditions on tree anchorage depends on the tree size. This study gives a new insight on young tree anchorage: roots may sustain by themselves anchorage, whereas adhesion between roots and surrounding soil may be negligible in sandy soil.

Keywords: roots, sandy soil, shear strength, tree anchorage, unsaturated soil

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Authors: T. M. Agbede, A. O. Adekiya

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Field experiments were conducted during 2013, 2014 and 2015 cropping seasons at Rufus Giwa Polytechnic, Owo, Ondo State, southwest Nigeria. The objective of the investigation was to determine the effect of Cocoa Pod Ash (CPA) and Poultry Manure (PM) applied solely and their combined form, as sources of fertilizers on soil properties, leaf nutrient composition, growth and yield of yam. Three soil amendments: CPA, PM (sole forms), CPA and PM (mixture), were applied at 20 t ha^-1 with an inorganic fertilizer (NPK 15-15-15) at 400 kg ha^-1 as a reference and a natural soil fertility, NSF (control). The five treatments were arranged in a randomized complete block design with three replications. The test soil was slightly acidic, low in organic carbon (OC), N, P, K, Ca and Mg. Results showed that soil amendments significantly increased (p = 0.05) tuber weights and growth of yam, soil and leaf N, P, K, Ca and Mg, soil pH and OC concentrations compared with the NSF (control). The mixture of CPA+PM treatment increased tuber weights of yam by 36%, compared with inorganic fertilizer (NPK) and 19%, compared with PM alone. Sole PM increased tuber weight of yam by 15%, compared with NPK. Sole or mixed forms of soil amendments showed remarkable improvement in soil physical properties, nutrient availability, compared with NPK and the NSF (control). Integrated application of CPA at 10 t ha^-1 + PM at 10 t ha^-1 was the most effective treatment in improving soil physical properties, increasing nutrient availability and yam performance than sole application of any of the fertilizer materials.

Keywords: cocoa pod ash, leaf nutrient composition, poultry manure, soil properties, yam

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Authors: Hassnen M. Jafer, W. Atherton, F. Ruddock, E. Loffill

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This study represents the results of an experimental work using two types of fly ashes as a cement replacement in soft soil stabilisation. The fly ashes (FA1 and FA2) used in this study are by-products resulting from an incineration processes between 800 and 1200 ˚C. The stabilised soil in this study was an intermediate plasticity silty clayey soil with medium organic matter content. The experimental works were initially conducted on soil treated with different percentages of FA1 (0, 3, 6, 9, 12, and 15%) to identify the optimum FA1 content. Then FA1 was chemically activated by FA2 which has high alkalinity by blending the optimum content of FA1 with different portions of FA2. The improvement levels were evaluated dependent on the results obtained from consistency limits and compaction tests along with the results of unconfined compressive strength (UCS) tests which were conducted on specimens of soil treated with FA1 and FA2 and exposed to different periods of curing (zero, 7, 14, and 28 days). The results indicated that the FA1 and FA2 used in this study effectively improved the physical and geotechnical properties of the soft soil where the index of plasticity (IP) was decreased significantly from 21 to 13.17 with 12% of FA1; however, there was a slight increase in IP with the use of FA2. Meanwhile, 12% of FA1 was identified as the optimum percentage improving the UCS of stabilised soil significantly. Furthermore, FA2 was found effective as a chemical activator to FA1 where the UCS was improved significantly after using FA2.

Keywords: fly ashes, soft soil stabilisation, waste materials, unconfined compressive strength

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Authors: Mthokozisi B. C. Simelane

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Despite the various efforts by governmental and non-governmental organizations aimed at eradicating the disease, malaria is said to kill a child every 30 seconds. Traditional healers use different concoctions prepared from medicinal plants to treat malaria. In the quest to bio-prospect plant-derived triterpenes for anti-malaria activity, we report here the in vivo antiplasmodial activity of ursolic acid acetate (ursolic acid isolated from dichloromethane extract of Mimusops caffra was chemically modified to its acetate derivative). The transdermal administration of ursolic acid acetate (UAA) dose dependently showed complete inhibition of the parasites’ growth at the highest concentration of 400 mg/kg after 15 days of Plasmodium berghei infection. UAA prevented the in vitro aggregation of MDH but did not prevent the expression of PfHsp 70 in E. coli XL1 blue cells. It, however, enhanced PfHsp70 ATPase activity with the specific activity of 65 units (amount of phosphate released 73.83 nmolPi/min.mg). Ursolic acid acetate prevented the formation of hemozoin (60 ± 0.02% at 6 mg/ml). The results suggest that Ursolic acid acetate possesses potential anti-malaria properties.

Keywords: Mimusops caffra, ursolic acid acetate, hemozoin, Malaria

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Authors: Rupa Rani, Vipin Kumar

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Endosulfan, an organochlorine pesticide is of environmental concern due to its apparent persistence and toxicity. It has been reported as contaminants in soil, air, and water and is bioaccumulated and magnified in ecosystems. The combined use of microorganisms and plants has great potential for remediating soil contaminated with organic compounds such as pesticides. The objective of this study was to evaluate whether the bacterial inoculation influences plant growth promotion, endosulfan degradation in soil and endosulfan accumulation in different plant parts. Lycopersicon esculentum L. (Tomato) was grown in endosulfan spiked soil and inoculated with endosulfan tolerant bacterial strains. Endosulfan residues from different parts of plants and soil were extracted and estimated by using gas chromatograph equipped with 63Ni electron capture detector (GC-ECD). The inoculation of bacterial strains into the soil with plants showed a beneficial effect on endosulfan degradation and plant biomass production. Maximum endosulfan (90%) degradation was observed after 120 days of bacterial inoculation in the soil. Furthermore, there was significantly less endosulfan accumulation in roots and shoots of bacterial strains inoculated plants as compared to uninoculated plants. The results show the effectiveness of inoculated endosulfan tolerant bacterial strains to increase the remediation of endosulfan contaminated soil.

Keywords: organochlorine pesticides, endosulfan, degradation, plant-bacteria partnerships

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Authors: Yu-Han Tao, Hui-Qin Xu

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The present study aimed to explain the protective effect of Cornus officinalis characteristic components, under AGEs damage to HUVEC. After cultured HUVEC adhered, Cornus officinalis characteristic components such as loganin, morroniside, oleanolic acid, ursolic acid and aminoguanidine (positive control dug) hatched, after 1h the AGEs (200 mg/L) were added. After 24h, LDH, SOD, MDA, NO, ET, and AngⅡ, TGF-β, IL-1β, ROS in the supernatant were determined. The results showed the Cornus officinalis characteristic compounds could improve vitality of SOD, NO, reduce the MDA, ET, AngⅡ, TGF-β, IL-1β, ROS significantly when compared with the model groug. Loganin, oleanic acid, ursolic acid, had significant protective effect on AGEs injured HUVEC. As a conclusion, characteristic components in Cornus officinalis had a positive effect after HUVEC injured by AGEs.

Keywords: Cornus officinalis, morroniside, oganin, oleanolic acid, ursolic acid

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Authors: Shiza Zafar

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The tannery effluents contaminated about 400 acres land area in Kasur, Pakistan, has been reclaimed by removing polluted water after the long term effluent logging from the nearby tanneries. In an effort to describe the status of reclaimed soil for agricultural practices, the results of physicochemical analysis of the soil are reported in this article. The concentrations of the parameters such as pH, Electrical Conductivity (EC), Organic Matter (OM), Organic Carbon (OC), Available Phosphorus (P), Potassium (K), and Sodium (Na) were determined by standard methods of analysis and results were computed and compared with various international standards for agriculture recommended by international organizations, groups of experts and or individual researchers. The results revealed that pH, EC, OM, OC, K, and Na are in accordance with the prescribed limits but P in soil exceeds the satisfactory range of P in agricultural soil. Thus, the reclaimed soil in Kasur can be inferred fit for the purpose of agricultural activities.

Keywords: soil toxicity, agriculture, reclaimed land, physico-chemical analysis

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Authors: Kanchan Vishwakarma, Shivesh Sharma, Nitin Kumar

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Soil is incoherent matter on Earth’s surface having organic and mineral content. The spatial variation of 4 soil enzyme activities and microbial biomass were assessed for two seasons’ viz. monsoon and winter along the latitudinal gradient in North-central India as the area of this study is fettered with respect to national status. The study was facilitated to encompass the effect of climate change, enzyme activity and biomass on nutrient cycling. Top soils were sampled from 4 sites in North-India. There were significant correlations found between organic C, N & P wrt to latitude gradient in two seasons. This distribution of enzyme activities and microbial biomass was consequence of alterations in temperature and moisture of soil because of which soil properties change along the latitude transect.

Keywords: latitude gradient, microbial biomass, moisture, soil, organic carbon, temperature

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Authors: Shreya Thusoo, Karan Modi, Ankit Kumar Jha, Rajesh Kumar

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Since the evolution of computational tools and simulation software, there has been considerable increase in research on Soil Structure Interaction (SSI) to decrease the computational time and increase accuracy in the results. To aid the designer with a proper understanding of the response of structure in different soil types, the presented paper compares the deformation, shear stress, acceleration and other parameters of multi-storey building for a specific input ground motion using Response-spectrum Analysis (RSA) method. The response of all the models of different heights have been compared in different soil types. Finite Element Simulation software, ANSYS, has been used for all the computational purposes. Overall, higher response is observed with SSI, while it increases with decreasing stiffness of soil.

Keywords: soil-structure interaction, response spectrum, analysis, finite element method, multi-storey buildings

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Authors: Hanamariam Mekonnen

Abstract:

Ethiopian farmers traditionally produce charcoal under several kilns on cultivated land: particularly in Kasiry micro-watershed Fagita Lekoma district of Northwestern Ethiopia. However, the effects of such soil heating and remnants of charcoal leftover on soils have not been adequately documented. Hence, this study tried to quantify the effects of such kiln sites on selected soil properties and wheat crop performance. Soils from four kiln sites were thus purposively sampled at depths of 0-20 cm, 20-40 cm and 40-60 cm and were compared with the respective soil layers of none-kiln sites from similar adjacent fields. While soil moisture content was sampled at kiln and none-kiln site in wet and dry seasons from each depth. In addition, a pot experiment was conducted using two sources of biochar (Acacia decurrens and Eucalyptus Camaldulensis) with four rates (0, 10, 20, and 40 t/ha) and compared with crops grown from soils of 1kiln sites without biochar application laid out in a CRD with three replications. The data were analyzed using SAS software Version 9.4.The result revealed notable variations of kiln site soils and along soil depth. The appreciable increased (p<0.05) soil pH (5.5 to 5.74), organic carbon (3.89 to 4.27%), TN (0.30 to 0.32%), CEC (32.59 to 35.23 cmolckg-1), Ca (6.44 to 7.9 cmolckg-1), Mg (4.48 to 5.46 cmolckg-1), and significantly (p<0.01) Av. P (30.25 to 46.4 ppm) and K (2.11 to 2.82 cmolckg-1) were recorded from the none-kiln to kiln soils, respectively. On the other hand, ex. acidity and aluminum, available Fe and Mn were reduced from 2.20 to 1.54, 1.95 to 1.31 cmolckg-1 and 57.46 to 41.40 and 5.65 to 3.86 ppm, respectively, from the control to the kiln. Soil texture was significantly affected by soil heating and along soil depth. The sand content was (p<0.05) varied between the value of 23% to 29% from none-kiln to kiln site, and clay content was (p<0.01) increased from 0-20 cm (32%) soil depth to 40-60 cm (43%) deeper soil. Significantly (p<0.05) higher Soil moisture content was recorded at none-kiln site (45.85%) compared to kiln (40.44%) in wet season, whereas in dry season, lower moisture content was revealed at kiln site (26%) compared to none-kiln (30.7%). As wet to dry season, soil moisture was decreased from 43% to 28% respectively. Bulk density (P<0.01) varied between 0.88 to 0.94 gcm-3 from control to kiln in dry season. Similarly, the value of soil pH (6.10), Av. P (58.12), exchangeable bases (Ca (9.83), Mg (6.19) and K (3.67)) were (p<0.01) higher at the 0-20 cm soil depth as compared to the deeper soils, the result of soil moisture (30 to 42%) and CEC (31 to 36 cmolckg-1) increased down the soil profile. After wheat harvest, soil pH, Av. P, CEC, and exchangeable bases (Mg, K and Na) were significantly higher in the kiln soil, while soil moisture and OC increased by the applied biochar of 20 and 40 ton/ha. High yield 2.28 gpot-1 (p<0.01) was recorded in kiln soil, growth parameters of wheat were significantly increased with increasing biochar rates.

Keywords: biochar, kasiry micro-watershed, kiln site, none-kiln site, soil properties

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Authors: Jacqueline Michella Anak Nathen

Abstract:

Subgrade soil is an essential component in the design of road structures as it provides lateral support to the pavement. One of the main reasons for the failure of the pavement is the settlement of the subgrade and the high susceptibility to moisture, which leads to a loss of strength of the subgrade. Construction over weak or soft subgrade affects the performance of the pavement and causes instability of the pavement. If the mechanical properties of the subgrade soils are lower than those required, the soil stabilisation method can be an option to improve the soil properties of the weak subgrade. Soil stabilisation is one of the most popular techniques for improving poor subgrade soils, resulting in a significant improvement in the subgrade soil’s tensile strength, shear strength, and bearing capacity. Soil stabilisation encompasses the various methods used to alter the properties of soil to improve its engineering properties. Soil stabilisation can be broadly divided into four types: thermal, electrical, mechanical, and chemical. The most common method of improving the physical and mechanical properties of soils is stabilisation using binders such as cement and lime. However, soil stabilisation with conventional methods using cement and lime has become uneconomical in recent years, so there is a need to look for an alternative, such as fiber. Although not a new technique, adding fiber is a very practical alternative to soil stabilisation. Various types of fibers, such as natural, synthetic, and waste fibers, have been used as stabilising agents to improve the strength and durability of subgrade soils. This review provides a comprehensive comparison of the effectiveness of natural, synthetic, and waste fibers in stabilising subgrade soils.

Keywords: subgrade, soil stabilisation, pavement, fiber, stabiliser

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Authors: Jeferson Brito Fernades, Breno Padovezi Rocha, Roger Augusto Rodrigues, Heraldo Luiz Giacheti

Abstract:

The geotechnical projects demand the appropriate knowledge of soil characteristics and parameters. The determination of geotechnical soil parameters can be done by means of laboratory or in situ tests. In countries with tropical weather, like Brazil, unsaturated soils are very usual. In these soils, the soil suction has been recognized as an important stress state variable, which commands the geo-mechanical behavior. Triaxial and direct shear tests on saturated soils samples allow determine only the minimal soil shear strength, in other words, no suction contribution. This paper briefly describes the triaxial test with controlled suction as well as discusses the influence of suction on the shear strength parameters of a lateritic tropical sandy soil from a Brazilian research site. In this site, a sample pit was excavated to retrieve disturbed and undisturbed soil blocks. The samples extracted from these blocks were tested in laboratory to represent the soil from 1.5, 3.0 and 5.0 m depth. The stress curves and shear strength envelopes determined by triaxial tests varying suction and confining pressure are presented and discussed. The water retention characteristics on this soil complement this analysis. In situ CPT tests were also carried out at this site in different seasons of the year. In this case, the soil suction profile was determined by means of the soil water retention. This extra information allowed assessing how soil suction also affected the CPT data and the shear strength parameters estimative via correlation. The major conclusions of this paper are: the undisturbed soil samples contracted before shearing and the soil shear strength increased hyperbolically with suction; and it was possible to assess how soil suction also influenced CPT test data based on the water content soil profile as well as the water retention curve. This study contributed with a better understanding of the shear strength parameters and the soil variability of a typical unsaturated tropical soil.

Keywords: site characterization, triaxial test, CPT, suction, variability

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Authors: H. Masaeli, R. Ziaei, F. Khoshnoudian

Abstract:

Shock response analysis of the soil–structure systems induced by near–fault pulses is investigated. Vibration transmissibility of the soil–structure systems is evaluated by Shock Response Spectra (SRS). Medium–to–high rise buildings with different aspect ratios located on different soil types as well as different foundations with respect to vertical load bearing safety factors are studied. Two types of mathematical near–fault pulses, i.e. forward directivity and fling step, with different pulse periods as well as pulse amplitudes are selected as incident ground shock. Linear versus nonlinear Soil–Structure Interaction (SSI) condition are considered alternatively and the corresponding results are compared. The results show that nonlinear SSI is likely to amplify the acceleration responses when subjected to long–period incident pulses with normalized period exceeding a threshold. It is also shown that this threshold correlates with soil type, so that increased shear–wave velocity of the underlying soil makes the threshold period decrease.

Keywords: nonlinear soil–structure interaction, shock response spectrum, near–fault ground shock, rocking isolation

Procedia PDF Downloads 306