Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Study of the curative role of "Draas" in evacuating dunes threatening roads in the Lower Algerian Sahara: physical model on a smaller scale

100%

Sebaa A. K. , Belhamra M. , Sebaa A. K. , Belhamra M.

nr 4-I

Study of the curative role of "Draas" in evacuating dunes threatening roads in the Lower Algerian Sahara: physical model on a smaller scale

89%

Sebaa A. K. , Belhamra M.

Archives of Civil Engineering

2018

tom Vol. 64, nr 4/I

15--35

Sand drifting on road networks in the region of the Lower Algerian Sahara is one of the main problems for the sector. Machines are repeatedly deployed to overcome this phenomenon. The long experience acquired while dealing with the removal of sand from roads pushed us to focus on obstacles called "Draas". The purpose of this study is to perform an optimization of these special protective structures called “Draas”, using a reduced physical model. Model tests were performed in flow channel. The principle of modeling the wind transport using a reduced model is to simulate the wind using a liquid stream while respecting the laws of hydraulic and sedimentological similarity. The results obtained are extrapolated to make a normal size prototype.

Can pit conductance be blocked under low ionic strength? Effect of deionized water on intervessel connectivity in a halophytic desert shrub (Tamarix gallica L.)

62%

Halis Y. , Benhaddya M. L. , Bachi O. E. , Lahcini A. , Belhamra M.

Acta Physiologiae Plantarum

2014

tom 36

nr 04

The fact that the porosity and permeability of intervessel pit pathways are significantly reduced by low ionic strength (deionized water) evokes the question of to what degree the pit membrane permeability can be reduced, and whether the network of laterally connected vessels can be affected by low ionic strength. Isolated stem segments of Tamarix gallica were used to (1) evaluate the effect of low ionic strength on lateral pit pathways in xylem of the halophytic plant; (2) visualize the blocked pathways by tracing the vessel network before and after treatments, using two apoplastic tracers. The results showed that the degree of intervessel contacts was significantly decreased by deionized water. Blockage of some laterally connected vessels could be clearly visualized in samples perfused with deionized water. These results suggested that some intervessel pit pathways might be blocked under low ionic strength, causing a reduction in the intervessel connectivity. Also, our results supported the idea that pit membranes might differ in their structure and/or chemical nature within the same xylem network. This study may contribute to an understanding of the complex interactions among sap salinity, pit pathways, and intervessel connectivity.