oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Genesis and Micromorphology of Saline and Gypsiferous Aridisols on Different Geomorphic Surfaces in Nough Area, Rafsanjan  [cached]
M. H. Farpour,M. K. Eghbal,H. Khademi
Journal of Science and Technology of Agriculture and Natural Resources , 2003,
Abstract: Gypsiferous Aridisols are of great importance and extent in arid and semi-arid environments. There is a close relationship between soil genesis and landscape positions. This study aimed to determine the genesis and classification of gypsiferous soils and to investigate the relationship between micro-and macro-morphology of gypsum crystals and geomorphic positions in Rafsanjan area. The study area is located in Nough, 30 km north of Rafsanjan with a mean annual precipitation of 60 mm. Seven representative pedons were selected on different geomorphic positions. Physico-chemical, micromorphological, XRD, and SEM observations were performed on soil samples. Rock pediment geomorphic surfaces, that are in fact peripheries of old closed water bodies in central Iran, are the source of gypsum in the area. Large gypsum pendants and microforms of lenticular, vermiform, platy, and interlocked gypsum plates are found in rock pediment. The amount of gypsum and the size of pendants decrease moving down the slope. Lenticular and interlocked gypsum plates are found in a transition of pediment and playa. Puffy ground is observed on the saline surface of playa. Lenticular and vermiform gypsum crystals increase down the slope, but alabastrine gypsum is the most dominant form of gypsum in the playa surface. Large amounts of soft gypsum nodules are found on the rock pediment surface (western slope). In addition, spindle form of gypsum and palycrete bundles are observed in this position. Wind action played a significant role in the genesis and development of soil in rock pediment. A close relationship was found between morphology of gypsum crystals and geomorphic positions.
Chemistry of Minerals and Geothermobarometry of Volcanic Rocks in the Region Located in Southeast of Bam, Kerman Province  [PDF]
Abdollah Yazdi, Afshin Ashja-Ardalan, Mohammad-Hashem Emami, Rahim Dabiri, Mohammad Foudazi
Open Journal of Geology (OJG) , 2017, DOI: 10.4236/ojg.2017.711110
Abstract: In this paper, tectonic and geothermobarometric environments have been studied with respect to the combination of pyroxene, olivine and plagioclase in volcanic rocks in the southeast of Bam. The combination of volcanic rocks in the region consists of olivine basalt, basalt, alkaline basalt, andesite, trachyandesite and pyroxene andesite. This combination is the result of the processes of crystallization and sometimes contamination. Plagioclase, clinopyroxene, olivine, and amphibole constitute the major minerals (rock forming minerals) in these rocks. Porphyritic to mega-porphyritic textures with microlithic, glumero-porphyritic and amigdaluidal matrix are observed. Based on the thermometric calculations, plagioclase, pyroxene, and olivine minerals and the rocks of this region are crystallized at a pressure of 1.5 to 7 kb and temperatures ranging from about 700°C to 1250°C.
Clay Mineralogy of Gypsiferous Soil Developed on Different Landforms in the Eastern Part of Isfahan  [cached]
H. R. Karimzadeh,A. Jalalian,H. Khademi
Journal of Science and Technology of Agriculture and Natural Resources , 2004,
Abstract: Clay minerals deserve special attention as they play a crucial role in many soils. The clay mineralogy of five gypsiferous soils from different landforms in eastern Isfahan was investigated using X-ray diffraction (XRD). In addition, soil aggregates and wind-deposited sediments were examined by scanning electron microscope (SEM) and analyzed by energy dispersive X-ray analyzer (EDX). The results indicate the presence of palygorskite, mica, kaolinite, chlorite, and quartz with a trace amount of vermiculite and randomly interstratified layers in all soils. Smectite occurs in soils of both the piedmont plain and old river terrace, but not in the alluvial fan soils. Mica, chlorite, quartz, and kaolinite were probably inherited from the parent material. Palygorskite seems to increase with depth in the alluvial fan, whereas, in the old terrace soils, this clay mineral decreases with depth. Palygorskite present in alluvial fan soil appears to have been formed authigenically when the basin was covered with shallow hyper-saline lagoons toward the end of the Tertiary. Palygorskite in the old terrace seems to be mostly detrital and an eolian origin of palygorskite is likely because a large amount of palygorskite is present in upper soil horizons. A higher proportion of smectite in deep soils of the old terrace, as compared with palygorskite, suggests the possibility of authigenic formation of smectite from palygorskite. .
Commercial production of crops irrigated with gypsiferous mine water
NZ Jovanovic, JG Annandale, AS Claassens, SA Lorentz, PD Tanner, ME Aken, FDI Hodgson
Water SA , 2002,
Abstract: The use of gypsiferous mine water for irrigation of agricultural crops is a promising technology that could add value through agricultural production and utilise mine effluent. Crop response to irrigation with gypsiferous mine water, as well as the impact on soil and groundwater resources were investigated in a three-year field trial set up at Kleinkopje Colliery (Witbank, Mpumalanga Province, South Africa). Sugar-beans, maize and wheat were irrigated with four centre pivots on virgin and rehabilitated land, under three irrigation management regimes using two qualities of mine water. Good crop yields were obtained compared to dry-land cropping. Waterlogging in certain areas of the fields indicated that especially rehabilitated land should be properly prepared and, where necessary, waterways built to prevent yield reduction. Soil salinity increased over the duration of the trial due to high concentrations of Ca2+, SO42- and Mg2+ in the irrigation water, but this never reached levels critical to yields of most crops. Exchangeable Ca2+ and Mg2+ in the soil increased with time, whilst K+ decreased. Plant analyses indicated possible nutrient deficiencies, which should be easily managed through corrective fertilisation. The groundwater impact was limited based on borehole measurements, indicating the presence of a buffer zone between the cropped soil profile and groundwater, but this should be monitored over a longer period. Commercial production of crops under irrigation with gypsiferous mine water is feasible and the resulting environmental impact is limited, but further research is required to confirm these findings over a longer period. WaterSA Vol.28(4) 2002: 413-422
Use of small-scale liquefaction features to assess paleoseismicity: an example from the Saline River fault zone, Southeast Arkansas, USA  [PDF]
Randel T. Cox,Christopher Lowe,Yanjun Hao,Shannon A. Mahan
Frontiers in Earth Science , 2014, DOI: 10.3389/feart.2014.00031
Abstract: Large-scale liquefaction features (e.g., sand blows, lateral-spread fissure vents) that can be recognized on remote-sensing imagery and photography have been of great utility in developing chronologies of paleo-earthquakes. In areas where large-scale features are obscured on imagery by forest cover and Holocene exposure is lacking, small-scale liquefaction features (e.g., convoluted bedding, clastic intrusions, foundered and suspended blocks, water-escape structures) offer an alternative data source that can be investigated in meter-scale excavations. In order to assess the geographic extent of Holocene sand blow fields in southeast Arkansas that were previously mapped on river terraces and flood plains using aerial photography, we investigated the distribution of small-scale liquefaction features in alluvium along streams within a forested region between the sand blow fields. Our results suggest that the fields are not continuous and do not reflect a single large liquefaction field related to paleo-earthquakes >M 6.5. Features at one of our sites suggests the Desha County sand blow field may be larger than presently mapped, and that the distance from the center of the field to the farthest liquefaction may be ~30 km. The empirical relationship of magnitude and distance to farthest liquefaction suggests a field of this size could have been produced by a M 6.3 earthquake. We also found Holocene liquefaction features that we interpret as resulting from ground shaking near previously documented Pleistocene and Holocene surface ruptures of the Saline River fault zone. Liquefaction during a paleo-earthquake (~M 5.5) may have coincided with movement on that fault zone ~AD 1700.
ANTHROPONOTIC CUTANEOUS LEISHMANIASIS IN THE CITY OF BAM, SOUTHEAST IRAN
A. Nadim,M.R. Aflatoonian
Iranian Journal of Public Health , 1995,
Abstract: Due to the high prevalence of anthroponotic cutaneous leishmaniosis (ACL) in Barn city, a survey was carried out to determine epidemiological characteristics of ACL in Barn in 1992. For this purpose, 23 out of the total 51 schools (elementary, junior high and senior high) were randomly selected and 6053 students were examined. The prevalence of acute sores and scars were 2% and 17% respectively. A map of the city was prepared, showing the residence of acute cases seen in schools. 3 parts with higher concentration of cases were selected and house - to - house visits were made, examining all age groups. In 2155 persons examined, the prevalence of acute cases was 3.6% and prevalence of scars 26.9%.
Results from the First Flight of BAM  [PDF]
G. S. Tucker,H. P. Gush,M. Halpern,W. Towlson
Physics , 1996,
Abstract: A new instrument, BAM (Balloon-borne Anisotropy Measurement), designed to measure cosmic microwave background (CMB) anisotropy at medium angular scales was flown for the first time in July of 1995. BAM is unique in that it uses a cryogenic differential Fourier transform spectrometer coupled to a lightweight off-axis telescope. The very successful first flight of BAM demonstrates the potential of the instrument for obtaining high quality CMB anisotropy data.
Saline Systems highlights for 2006
Shiladitya DasSarma
Aquatic Biosystems , 2007, DOI: 10.1186/1746-1448-3-1
Abstract: Saline environments and biodiversity associated with such environments are challenged from both human activities and natural dynamics. For example, recent climatic changes have led to increasingly intense monsoon rains in some regions and to decreasing precipitation levels in others. Nowhere are such changes more in evidence than in the salinity characteristics of many coastal estuarine bodies and inland saline lakes. Saline Systems specializes in meeting the publication needs of researchers working in such saline environments and provides an interdisciplinary and readily accessible forum for scientists worldwide [1]. In 2006, Saline Systems has published a wide variety of important studies on saline environments, including detailed analyses of halophilic species inhabiting them, and those important to biotechnology and aquaculture.Four reports in Saline Systems, volume 2 established baseline hydrogeochemistry for several geographically dispersed saline ecosystems. The paper by Weber et al. [2] provided perspective on the effects of more than a century of human activity on Fleet, Dorset, a coastal lagoon in the southeast of Britain, using modeling of historical data on land use, livestock, and human population. The study found that livestock were the main nutrient source throughout, but inputs from inorganic fertilizers were substantial in the modern period, and an ancient swan community also contributed to the on-going environmental challenges. The authors concluded that a combination of measures is essential to address these challenges.Two studies reported on salinity and hydrological studies of salt ponds in islands, the British Virgin Islands in the Caribbean [3] and Christmas and Washington Islands in the Pacific [4]. The study of Jarecki and Walkey [3] found that salt ponds were increasingly threatened by rapid coastal fluctuations and isolated from the sea, exhibiting dramatic fluctuations in salinity in response to rainfall and evaporation. The study of Saen
Prediction of the environmental impact and sustainability of large-scale irrigation with gypsiferous mine-water on groundwater resources
JG Annandale, NZ Jovanovic, FDI Hodgson, BH Usher, ME Aken, AM van der Westhuizen, KL Bristow, JM Steyn
Water SA , 2005,
Abstract: Irrigation of agricultural crops is one of the most cost-effective options for the utilisation of gypsiferous mine wastewater. In addition, it creates the opportunity to produce crops during the dry season. Gypsum is a slightly soluble salt and concentrating the gypsiferous soil solution through crop evapotranspiration precipitates gypsum in the soil profile, removing it from the water system and reducing the potential for groundwater pollution. In previous research, it was found that crops can be commercially produced under irrigation with gypsiferous mine-water with no obvious impact on groundwater in the short term (3 years). It was, however, recommended that monitoring should continue to confirm findings over a longer period and for different conditions. A research project was therefore initiated in 2001 to determine the impact of irrigation with several gypsiferous water/soil combinations on crop performance, soil properties and groundwater quality. Field trials were carried out in South Africa on three mines: Kleinkopjé and New Vaal Collieries (Anglo Coal), and at Syferfontein (Sasol). Different crop and pasture species were grown on different soil types under centre-pivot irrigation with different mine-water qualities. Intensive monitoring systems were established in each irrigated field to determine the components of the soil-water and salt balance. Boreholes were also installed to monitor groundwater level and quality. Field water and salt balance data were used for calibration and validation of the mechanistic, generic crop, Soil-Water Balance (SWB) Model. The results of the field trials indicated that high crop and pasture yields can be obtained, provided site selection, land preparation, fertilisation and irrigation water management are appropriate. The results of the soil-water and salt balance studies indicated that considerable volumes of mine-water can be used and substantial amounts of salts can be removed from the water system through precipitation of gypsum in the soil profile. The groundwater impact was limited based on borehole measurements, indicating the presence of a zone of attenuation between the cropped soil profile and groundwater, but this should be monitored over a longer period. With appropriate management, water and salt runoff, and under specific conditions, drainage and salts leached can be intercepted, thereby minimising unwanted impacts on groundwater. Thirty-year scenario simulations were run with SWB and the generated salt loads from this model were used as input into a separate groundwater model in order to predict the likely long-term effects of irrigation with gypsiferous mine-water on groundwater. The results of these simulations showed that while salts reached the groundwater, there was a drop in concentration of the plume as it moved away from the irrigated area. This was due largely to dilution by infiltration from rainfall recharge and the dispersive characteristics of the aquifer. The simulations als
Classification of Cancer Recurrence with Alpha-Beta BAM  [PDF]
María Elena Acevedo,Marco Antonio Acevedo,Federico Felipe
Mathematical Problems in Engineering , 2009, DOI: 10.1155/2009/680212
Abstract: Bidirectional Associative Memories (BAMs) based on first model proposed by Kosko do not have perfect recall of training set, and their algorithm must iterate until it reaches a stable state. In this work, we use the model of Alpha-Beta BAM to classify automatically cancer recurrence in female patients with a previous breast cancer surgery. Alpha-Beta BAM presents perfect recall of all the training patterns and it has a one-shot algorithm; these advantages make to Alpha-Beta BAM a suitable tool for classification. We use data from Haberman database, and leave-one-out algorithm was applied to analyze the performance of our model as classifier. We obtain a percentage of classification of 99.98%.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.