Free-Boundary Seepage from Asymmetric Soil Channels
We present an inverse method for the study of the seepage from soil channels without lining. We give integral representations of the complex potential, velocity field, stream lines, free phreatic lines, and contour of the channel by means of Levi-Civita's function 𝜔. For different values of the Taylor coefficients of 𝜔, we calculate numerically the contour of the channel, the phreatic lines, the seepage loss, the velocity field, the stream lines, and the equipotential lines. Examples are given for various symmetric or asymmetric channels, with smooth contours or with angular points.
Analysis and Estimation of Downward Seepage from Lining and Unlining Triangular Open Channel
: This research concerns to study the quantity of seepage running downward from triangular open channel with lining and unlining using computer program SEEP/W (which is a sub-program of Geo-Studio). Using SEEP/W experiments two groups were carried out with three different downstream slopes of triangular open channel, three different upstream slopes, three variable free board, three different height of triangular open channel, for first group using three different permeability for soil around the triangular open channel and for second group using three different permeability for lining layer and for soil around triangular open channel. For each run the quantity of seepage were determined. Dimensional analysis was used with helping of the theoretical results to develop empirical equations in order to determine the quantity of seepage running downward the triangular open channel for lining and unlining. Also, Verify the SEEP/W results with analytical method of Vedernikov’s equation. Results show good agreement for triangular open channel unlining layer.
Time and Heritage
As a historian studying what can be considered a form of intellectual history, I have slowly come to adopt Michel de Certeau’s observation made at the end of the 1980s that ‘objectifying the past, for the last three centuries, has undoubtedly left unconsidered time within a discipline that has continued to use it as a taxonomic instrument’. To a certain degree, time has become commonplace for the historian who has preserved or instrumentalized it. It is not considered because it is inconceivable, but because we do not think of it or, more simply, we do not think about it. As a historian attempting to pay attention to the time I’m living in, I have thus, like many others, noticed the swift development of the category of the present until it has become obvious that the present is omnipresent. This is what I refer to here as ‘presentism’.