The safety of lifelines, as the most important urban facilities, under different conditions highly depends on the safe design and performance of these buried structures. This cannot be achieved unless their actual behaviors are well understood and considered at the designing stage. A new physical model was developed in Amirkabir University of Technology to study the behavior of buried pipes und...

We report results on the synchronization of an organ pipe either by a second pipe or by a loudspeaker, positioned side by side. Classical theory suggests oscillation death for the synchronization of two organ pipes. With our measurements we clearly exclude this scenario. Rather, we identify the aeroacoustical coupling by the oscillating wind sheet at the pipe mouth as the source of a self-regul...

We study the version of the C-PLANARITY problem in which edges connecting the same pair of clusters must be grouped into pipes, which generalizes the STRIP PLANARITY problem. We give algorithms to decide several families of instances for the two variants in which the order of the pipes around each cluster is given as part of the input or can be chosen by the algorithm.

We present a brief historical overview of the classical theory of a radiating point charge, described by the Lorentz-Dirac equation. A recent development is the discovery of tunnelling of a charge through a potential barrier, in a completely classical context. Also, a concrete example is discussed of the existence of several physically acceptable solutions for a range of initial data. We end by...

A theory of field induced electron emission from electrolytic conductors is proposed in which an electron associated with an immobile anion at the surface is destabilised as a cation moves into the bulk. This electron may be thermally emitted over a field-lowered barrier. Equations are developed for the potential barrier that must be surmounted by the electron and the form of the current versus...

We show that the sphaleron energy which identifies with the (instanton) potential barrier for B-violation is reduced in the presence (background) of an electroweak Z-string. We also show that for large enough Higgs coupling, λ, the sphaleron energy can go negative. For such λ, electroweak Z-strings can reduce their energy by accumulating sphaleron bound states. This further endows them with bar...

Many stormwater modeling problems consider watersheds comprised of complex flow networks including surfaces, streets, pipes, and channels. Ideally, hydrologic methods would be used to model the accumulation of runoff on surfaces while hydraulic methods would be used to explicitly model the flow in each street, pipe, and channel. In many practical circumstances, however, only the largest pipes a...

District heating networks are used worldwide, especially in Scandinavian countries and also in many other countries, e.g. Germany, Russia, United States, South Korea and China. From an environmental point of view, district heating networks are a good alternative to more traditional building heating systems. In 1970th, the third generation of district heating systems was established on the marke...

Viscoelastic coatings are often used to protect pipelines in the oil and gas industry. However, over time defects and areas of corrosion often form in these pipelines and so it is desirable to monitor the structural integrity of these coated pipes using techniques similar to those used on uncoated pipelines. A common approach is to use ultrasonic guided waves that work on the pulse-echo princip...