نتایج جستجو برای: precipitation variation has little effect on karst dissolution rates

تعداد نتایج: 9836548  

Journal: :مرتع و آبخیزداری 0
مهرنوش قدیمی دکتری ژئومورفولوژی دانشگاه تهران حسن احمدی استاد گروه آبخیزداری دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران ابراهیم مقیمی استاد دانشکده جغرافیا، دانشگاه تهران منصور جعفربیگلو استادیار دانشکده جغرافیا، دانشگاه تهران

to evaluate the hydrogeochemical characteristics of karst water resources of oshtorankooh, chemistry details of springs has been considered as the most important evacuator of karst resources. this research has been performed to study hydrogeochemical nature of karst springs and their origin with an emphasis on the type of formation.  accordingly, five samples of the water of permanent springs o...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - پژوهشکده مهندسی فرایند 1395

abstract: mineral scaling in oil and gas production equipment is one of the most important problem that occurs while water injection and it has been recognized to be a major operational problem. the incompatibility between injected and formation waters may result in inorganic scale precipitation in the equipment and reservoir and then reduction of oil production rate and water injection rate. ...

Journal: :Hydrology and Earth System Sciences 2023

Abstract. Cave-monitoring studies clarify the climatic, surface vegetation, and karst processes affecting cave system lay foundation for interpreting geochemical stalagmite records. Here we report monitoring of air, bedrock chemistry, drip water δ13CDIC, δ18O, δD, as well 16 trace elements, covering a full annual cycle spanning months between November 2019 March 2021 in La Vallina northwestern ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1391

in this research we have studied the effect of some transition-metals (cu, ag and au) substitutions on two-electron reduction potential of flavins by application of dft method. all geometries have been optimized at blyp level of theory and “6-31+g** + lanl2dz” mixed basis set. the frequency job at the same method and basis sets has been performed to obtain gibbs free energy of compounds. it h...

پایان نامه :0 1374

having conducted the experiment and analysed the data, the researcher computed the groups mean scores and variances for the test relating to the research question. as the final atep, a t-test was conodonted for the hypothesis. as noted earlier, the significance level was determined at .05 and .01 respectively. the observed t-value was higher than the critical t-value at. 5 and .01 levels. conse...

Vulnerability assessment and mapping of hazard pollution is raised on as an important management strategy to protect the karst. Karstic aquifers in semi-arid regions of the West of Iran with regard to the natural conditions of the region, are susceptible to contamination. Estimation of amount and vulnerability mapping of aquifers in the karst religion of Bistoun- Paraw – Kermanshah plain agains...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2017
Adam V Subhas Jess F Adkins Nick E Rollins John Naviaux Jonathan Erez William M Berelson

Near-equilibrium calcite dissolution in seawater contributes significantly to the regulation of atmospheric [Formula: see text] on 1,000-y timescales. Despite many studies on far-from-equilibrium dissolution, little is known about the detailed mechanisms responsible for calcite dissolution in seawater. In this paper, we dissolve 13C-labeled calcites in natural seawater. We show that the time-ev...

1997
W. B. White

Chemical reactions pertinent to karst systems divide broadly into (a) speciation reactions within aqueous solutions, (b) dissolution/precipitation and other acid/base reactions between aqueous solutions and solid minerals, and (c) redox reactions involving various carbon and sulfur-bearing species. As a backdrop against which other chemistry can be evaluated, selected phase diagrams and equilib...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید باهنر کرمان - دانشکده ادبیات و علوم انسانی 1389

abstract translation has become a cultural act which plays a significant role in human life. with the emergence of functional translation theories, and skopos theory in particular, translation has been considered as a purposeful, interpersonal and intercultural activity which is produced for particular recipients and directed by a specific purpose. this purpose determines the translatio...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1389

growing demands and requires of high data rate systems cause significant increase of high frequency systems for wideband communication applications. as mixers are one of the main blocks of each receivers and its performance has great impact on receiver’s performance; in this thesis, a new solution for ku-band (12-18 ghz) mixer design in tsmc 0.18 µm is presented. this mixer has high linearity a...

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