نتایج جستجو برای: submerged bridge
تعداد نتایج: 61705 فیلتر نتایج به سال:
CH4 and N2O emissions from Spartina alterniflora and Phragmites australis in experimental mesocosms.
Spartina alterniflora, a perennial grass with C(4)-photosynthesis, shows great invading potential in the coastal ecosystems in the east of China. We compared trace gas emissions from S. alterniflora with those from a native C(3) plant, Phragmites australis, by establishing brackish marsh mesocosms to experimentally assess the effects of plant species (S. alterniflora vs. P. australis), flooding...
Living stromatolites growing in a hot spring in Yellowstone National Park are composed of silica-encrusted cyanobacterial mats. Two cyanobacterial mat types grow on the stromatolite surfaces and are preserved as two distinct lithofacies. One mat is present when the stromatolites are submerged or at the water-atmosphere interface and the other when stromatolites protrude from the hot spring. The...
The amphibious leafless sedge Eleocharis vivipara develops C 4 -like traits as well as Kranz anatomy under terrestrial conditions, but it develops C 3 -like traits without Kranz anatomy under submerged conditions. When submerged plants are exposed to aerial conditions, they rapidly produce new photosynthetic tissues with C 4 -like traits. In this study, experiments were performed to determine w...
INTRODUCTION Central to the management of salmonid fisheries in the UK is assessment of the size and age composition of adult fish returning to fresh water. Assessment is most commonly achieved by mark-recapture studies, full river trapping or by the use of fish counters. In hydroelectric installations in Scotland, the electrical resistivity counter is presently employed to count fish automatic...
N.sitophila was grown under controlled conditions of solid state and submerged fermentation on Sago hampas. The optimum conditions of protein enrichment previously established for sugar beet pulp was used for this study. Under this condition the protein content of Sago hampas under solid state increased from 1.4 to 14.45% (W/W) whereas for Sago hampas and Sago starch, the protein content under ...
Invasion by free-floating species, such as Eichhornia crassipes, is one of the most critical threats to the biodiversity and sustainability of wetland ecosystems, where all plants experience spatial heterogeneity in substrate nutrients. However, few studies have focused on the effects of free-floating invaders on the capacity of submerged plants to utilize substrate nutrients. A 10-week greenho...
this paper presents a new bridge management system (j-bms). it is integrated with a concrete bridge rating expert system that can be used to evaluate the serviceability of existing concrete bridges. the proposed j-bms not only evaluates the performance of bridges, but also offers a rehabilitation strategy based on a combination of maintenance cost minimization and quality maximization. in this ...
مبدل های چند سطحی در زمینه های توان بالا و ولتاژ بالا کاربردهای زیادی را داشته است. هدف یک مبدل چند سطحی، ساختن یک ولتاژ سینوسی از سطوح مختلف ولتاژ dc است. مبدل های چند سطحی ساختارهای متفاوت دارند. یکی از ساختارهای مرسوم ، مبدل های چندسطحی کسکید می باشد. مبدل های چندسطحی کسکید از سری کردن h-bridge ها بدست می آید. اگر منابع تغذیه ولتاژ dc اعمال شده به تمام پل ها یکسان باشد، مبدل را مبدل چندسطحی ...
In this study, we have investigated variations in the potential of floating and submerged leaves of longleaf pondweed (Potamogeton nodosus) to withstand silver ion (Ag+)-toxicity. Both floating and submerged leaves changed clear colorless AgNO3 solutions to colloidal brown in the presence of light. Transmission electron microscopy revealed the presence of distinct crystalline Ag-nanoparticles (...
Submerged vanes are low aspect ratio flow-training structures mounted vertically on the river bed at an angle to the prevailing flow. The aim of application of vane is to generate a secondary circulation in the main flow, designed to modify the near-bed flow pattern and thus redistribute flow and sediment transport within the channel cross section. Collar is a flat sheet with low thickness fixe...
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