A mathematical model for unsteady mixed flows in closed water pipes

We present the formal derivation of a new unidirectional model for unsteady mixed flows in non uniform closed water pipe. In the case of free surface incompressible flows, the \FS-model is formally obtained, using formal asymptotic analysis, which is an extension to more classical shallow water models. In the same way, when the pipe is full, we propose the \Pres-model, which describes the evolution of a compressible inviscid flow, close to gas dynamics equations in a nozzle. In order to cope the transition between a free surface state and a pressured (i.e. compressible) state, we propose a mixed model, the \PFS-model, taking into account changes of section and slope variation

Managing Spoilers in a Hybrid War: The Democratic Republic of Congo (1996-2010)

Scholarship on the management of spoilers in a hybrid type of conflict is almost non-existent. Through an examination of the recent Congolese wars and peace efforts (1996–2010), we develop an understanding of how spoilers are managed in a conflict characterised by both interstate and intrastate dynamics. Certainly, more strategies of dealing with spoiler behaviours in this type of conflict are likely to emerge as similar cases are investigated, but our discussion recommends these non-related, but strongly interacting principles: the practice of inclusivity, usually preferred in the management of spoilers, is more complex, and in fact ineffective, particularly when concerned groups’ internal politics and supportive alliances are unconventional. Because holding elections is often deemed indispensable in peacemaking efforts, it is vital that total spoilers be prevented from winning or disrupting them. The toughest challenge is the protection of civilians, especially when the state lacks a monopoly on the use of violence and governance remains partitioned across the country

Unit cost-functions for value estimation of waterborne sewer infrastructure

Please help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected] Ingenieurswes