نتایج جستجو برای: medium sand

تعداد نتایج: 263517  

2015
Shengbo Xie Jianjun Qu Yuanming Lai Xiangtian Xu Yingjun Pang

Previous research has shown that the temperature of underlying permafrost decreases after the ground surface is covered with sand. No significant conclusions have yet been drawn that explain why this happens, because the heat transfer mechanism effects of the sand layer on the underlying permafrost remain unclear. These mechanisms were studied in the present work. We found that the upward short...

2015
KEON KIM CHUN CHOI

There are several types of firing tests of cannonballs. In ground firing tests, cannonballs without gunpowder charged are fired against sand heap. When a cannonball collides into sand, the cannonball’s penetration depth, stress and sand temperature depend on the sand properties. Sand tends to become harder than before after plenty of cannonball firing. This is because kinetic energy of a cannon...

Journal: :Journal of the Engineering Mechanics Division 1975

2012
Rajeev Goel S K Kapoor Kshipra Misra R K Sharma

Present study is carried out for the removal of As(lII) from water using commonly available adsorbents such as sand, from Yamuna river (Delhi ), as well as from Ganga river (Kolkata), activated carbon, Hametite ore and sand -iron scrap mixture. All these adsorbents are used as received but sand and activated carbon which do not show much adsorption for As(lII) are modified by treating with diff...

2012
Xuejun Yang Carol C. Baskin Jerry M. Baskin Guangzheng Liu Zhenying Huang

The success of seedling establishment of desert plants is determined by seedling emergence response to an unpredictable precipitation regime. Sand burial is a crucial and frequent environmental stress that impacts seedling establishment on sand dunes. However, little is known about the ecological role of seed mucilage in seedling emergence in arid sandy environments. We hypothesized that seed m...

Journal: :Journal of nematology 1982
J M Cupello J J Petersen A R Chauthani

To prevent losses during long-distance shipment, a new delivery system was developed for the mosquito parasite Romanomermis culicivorax. A specially designed shipping container, two types of culture media (sand and a mixture of sand, vermiculite, and charcoal [SVC]), and two types of insert (polystyrene and polyester urethane foam [PUF]) were tested. Cultures shipped in SVC/PUF insert combinati...

2009
F. Martínez S. Castillo E. Carmona M. Avilés

The dispersion of soilborne plant pathogens could be greater in closed soilless growing systems than in open ones. The effect of three soilless growing systems (open, closed and closed with slow sand filtration) on the dispersion of Verticillium dahliae propagules and the severity of the disease in strawberry (Fragaria × ananassa Duch.) has been analysed. V. dahliae dispersion in a closed syste...

Journal: :Journal of contaminant hydrology 2015
H Kurlanda-Witek B T Ngwenya I B Butler

Biofilms are a common constituent of the subsurface and are known to influence contaminant transport; however only a few studies to date have addressed microbial controls on nanoparticle mobility in porous media. The impact of a 3-day Pantoea agglomerans biofilm on the mobility of zinc oxide (ZnO) nanoparticles was studied in column experiments containing sand and glass beads at near-neutral pH...

Journal: :Journal of water and health 2009
Richard L Whitman Katarzyna Przybyla-Kelly Dawn A Shively Meredith B Nevers Muruleedhara N Byappanahalli

Beach sand contains fecal indicator bacteria, often in densities greatly exceeding the adjacent swimming waters. We examined the transferability of Escherichia coli and F+ coliphage (MS2) from beach sand to hands in order to estimate the potential subsequent health risk. Sand with high initial E. coli concentrations was collected from a Chicago beach. Individuals manipulated the sand for 60 sec...

Journal: :Water science and technology : a journal of the International Association on Water Pollution Research 2001
H Brix C A Arias M del Bubba

Sorption of phosphorus (P) to the bed sand medium is a major removal mechanism for P in subsurface flow constructed wetlands. Selecting a sand medium with a high P-sorption capacity is therefore important to obtain a sustained P-removal. The P-removal capacities of 13 Danish sands were evaluated and related to their physico-chemical characteristics. The P-removal properties of sands of differen...

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