Author
Francois Clemens
Other affiliations: Norwegian University of Science and Technology, City University of New York
Bio: Francois Clemens is an academic researcher from Delft University of Technology. The author has contributed to research in topics: Sanitary sewer & Combined sewer. The author has an hindex of 23, co-authored 170 publications receiving 2032 citations. Previous affiliations of Francois Clemens include Norwegian University of Science and Technology & City University of New York.
Topics: Sanitary sewer, Combined sewer, Asset management, Flood myth, Wastewater
Papers published on a yearly basis
Papers
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TL;DR: Using data from the Eindhoven wastewater system in The Netherlands both dry weather flow and wet weather flow situations have been studied, finding the smallest catchment area consistently shows the largest mean peak factors and vice versa.
24 citations
TL;DR: In this article, the influence of the coding system on quality of inspection data is studied, and it is concluded that the increase in detail does not lead to more information, and that added detail leads to more mistakes.
Abstract: In order to provide information about the decisions on proactive and reactive maintenance, sewers are visually inspected. Previous research showed that the quality of visual inspection data is questionable. A coding system prescribes which and how defects should be recorded. This article studies the influence of the coding system on quality of inspection data. A database with the examinations of the Dutch sewer inspector course is studied. Through time, 10 photos of the inside of a sewer were evaluated according to two different coding systems: the concise NEN3399:1992 and the more detailed and extensive NEN3399:2004.This article compares both coding systems by evaluating candidate responses to photos showing sewers with clearly visible defects. Results show that added detail in the coding system of 2004 leads to more mistakes. Therefore, it can be concluded that the increase in detail does not lead to more information.
24 citations
TL;DR: IR frame analysis and 2D temperature mapping demonstrate that: i) the detection limit is very low (ratio between lateral and main discharges: 0.025) and ii) the quantification of the lateral discharge is impossible.
23 citations
TL;DR: The much over-looked element in new sanitation, the transport systems which bridge the source and treatment facilities, is the focus of this study, and the viscosity of black-water with ground kitchen waste is found to be higher than that of black water, which can be attributed to the presence of larger particles in the slurry.
22 citations
TL;DR: In this paper, the authors present a methodology to determine the probability to overestimate, underestimate, or accurately estimate the real condition of a pipe using visual inspection, based on the analysis of double inspections of the same sewer pipes and has been tested using the extensive data-set of the city of Braunschweig in Germany.
Abstract: Closed Circuit Television Inspection is used since decades as industry standard for sewer system inspection and structural performance evaluation. In current practice, inspection data are helpful to support asset management decisions. However, the quality and uncertainty of sewer condition assessment is rarely questioned. This article presents a methodology to determine the probability to underestimate, overestimate or accurately estimate the real condition of a pipe using visual inspection. The approach is based on the analysis of double inspections of the same sewer pipes and has been tested using the extensive data-set of the city of Braunschweig in Germany. Results indicate that the probability to inspect correctly a pipe in poor condition is close to 80%. The probability to overestimate the condition of a pipe in bad condition (false negative) is 20% whereas the probability to underestimate the condition of a pipe in good condition (false positive) is 15%. Finally, sewer condition evaluation ...
21 citations
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6,278 citations
4,201 citations
Journal Article•
TL;DR: In this article, the authors present a document, redatto, voted and pubblicato by the Ipcc -Comitato intergovernativo sui cambiamenti climatici - illustra la sintesi delle ricerche svolte su questo tema rilevante.
Abstract: Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.
4,187 citations
01 Jan 1997
TL;DR: The boundary layer equations for plane, incompressible, and steady flow are described in this paper, where the boundary layer equation for plane incompressibility is defined in terms of boundary layers.
Abstract: The boundary layer equations for plane, incompressible, and steady flow are
$$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$
2,598 citations