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

تعداد نتایج: 9836548  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه 1377

the methods which are used to analyze microstrip antennas, are divited into three categories: empirical methods, semi-empirical methods and full-wave analysis. empirical and semi-empirical methods are generally based on some fundamental simplifying assumptions about quality of surface current distribution and substrate thickness. thses simplificatioms cause low accuracy in field evaluation. ful...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - پژوهشکده علوم انسانی و اجتماعی 1390

this study attempts to investigate the effect of peers’ revision in comparison to that of the teacher, and whether peers’ comments and teachers’ comments facilitate students’ revision? if yes, which one is more effective? also attempts have been made to see which aspects of language are more highlighted by peers versus teachers when commenting. besides, it is investigating the student’s attitud...

Journal: :Acta Carsologica 2007

The purpose of this study is to investigate the performance and three-dimensional behavior of the flow in a mixed flow pump and the way cavitation phenomenon is affected by different parameters such as fluid temperature, pump speed and flow rate. Computational fluid dynamic software FLUENT 6.3 was utilized to simulate the whole flow field of the pump. RNG k-ε model combined with standard wall f...

2008
Caihong Hu Yonghong Hao Tian-Chyi J. Yeh Bo Pang Zening Wu

In China, 9Ð5% of the landmass is karst terrain and of that 47,000 km2 is located in semiarid regions. In these regions the karst aquifers feed many large karst springs within basins of thousands of square kilometres. Spring discharges reflect the fluctuation of ground water level and variability of ground water storage in the basins. However, karst aquifers are highly heterogeneous and monitor...

2011
Nighat Razvi Saeed Ahmad Siddiqui Lubna Ghazal Khan

The present work was conducted on the effect of surfactant on the dissolution rate of ibuprofen tablets. The cationic (Cetyl Trimethyl bromide) and anionic (Sodium dodecyl sulphate) surfactant present in the dissolution media have remarkable effect on the dissolution rate of Ibuprofen. Maximum dissolution was obtained in the presence of anionic surfactant (Sodium dodecyl sulphate) at 0.5% conce...

Journal: :Corrosion Science 2021

• The nanoscale TiO 2 layer was covered by anatase and ilmenite crystallites. thin evolution modelled a Loriers-Haycock model. Titanium precipitation ratii were defined measured. A phenomenological model proposed to link mass variation corrosion rate. Corrosion rates of all studied materials stand between 6.6 μm/year at 300 °C. titanium alloys in primary water °C led global weight gain due oxid...

2017
Yen Adams Jann Rune Ursin

In terms of storage capacity and containment efficiency, deep saline aquifers are among the best candidates for CO2 storage. However, salt precipitation in the wellbore vicinity and fines mobilization ensued from in situ mineral dissolution could impair CO2 injectivity and reduce the quality and capacity of deep saline reservoirs for CO2 storage. The mechanisms of salt precipitation and its imp...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - پژوهشکده فنی و مهندسی 1388

asymmetric polyethersulfone (pes) microfiltration flat sheet membranes were composed by the phase inversion method (pim) and were used as supports. composite membranes were fabricated by coating silicone rubber as selective layer. effect of different concentrations of pes and pdms and different solvent such as nmp, dmf and dms effects as pes solvents and support thickness and different coagulat...

Journal: :Global change biology 2013
Dolaporn S Novem Auyeung Vidya Suseela Jeffrey S Dukes

Shifts in nitrogen (N) mineralization and nitrification rates due to global changes can influence nutrient availability, which can affect terrestrial productivity and climate change feedbacks. While many single-factor studies have examined the effects of environmental changes on N mineralization and nitrification, few have examined these effects in a multifactor context or recorded how these ef...

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