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3D numerical simulation of flow field around twin piles

100%

Amini A. , Parto A. A.

Acta Geophysica

2017

tom Vol. 65, no. 6

1243--1251

In this study to identify the flow pattern and local scour mechanism around pile groups, the flow field was simulated using FLOW-3D software. A pair of pile on a flat-bed channel with side by side and tandem arrangements was investigated. To establish Navier–Stokes equations, the RNGk-ε turbulence model was used and the results were verified using experimental data. In case of FLOW-3D capability, it was found that the software was able to properly simulate the expected interaction between the pile groups. The results of flow field simulation showed that Reynolds number and the pile spacing are the most influential variables in forming vortices. The flow around tandem pile and the downward flow around wake vortices were more intense and complicate in comparison with side by side arrangements and single pile.

Application of Electrical Resistivity Imaging for Engineering Site Investigation. A Case Study on Prospective Hospital Site, Varamin, Iran

100%

Amini A. , Ramazi H.

Acta Geophysica

2016

tom Vol. 64, no. 6

2200--2213

The article addresses the application of electrical resistivity imaging for engineering site investigation in Pishva Hospital, Varamin, Iran. Some aqueduct shafts exist in the study area backfilled by loose materials. The goals of this study are to detect probable aqueduct tunnels and their depth, investigate filling quality in the shafts as well as connection(s) between them. Therefore, three profiles were surveyed by dipoledipole electrode array. Also, to investigate the potentially anomalous areas more accurately, five additional resistivity profiles were measured by a Combined Resistivity Sounding-Profiling array (CRSP). According to the results of 2-D inversion modelling, a main aqueduct tunnel was detected beneath the central part of the site. Finally, the resistivity pattern of the detected aqueduct system passing the investigated area was provided using the obtained results.

A low-jitter, full-differential PLL in 0.18μm CMOS technology

70%

Modarresi F. , Ghasemzadeh M. , Mazlumi M. , Amini A. , Abolfathi T.

tom Vol. 7, nr 4

119--122

This paper presents a Phase Locked Loop (PLL) which works with minimum jitter in the operation frequency range of 600MHZ to 900MHZ. Utilizing a full differential architecture that consists of several blocks of differential VCO, a differential PFD and a differential CPL leads to limiting the RMS jitter to 4.06ps, with 50mV power supply noise in the frequency range of 750MHz. Simulation results using 0.18μm CMOS TSMC standard technology demonstrate the power-consumption of 4.6mW at the supply voltage of 1.8V.

Radiotracer technique for pipeline leak detection in the National Iranian Oil Company

70%

Rahimi H. , Naimpour M. A. , Abedinzadeh A. , Amini A. , Kraś J.

Nukleonika

1999

tom Vol. 44, nr 3

491-498

Physical and chemical principles of application of isotope tracers to control of tightness and localization of leaks in underground pipelines have been presented. The method shows many advantages. It is sensitive and easy to apply. The test and preliminary works are not time-consuming. In addition, the isotopic test can be carried out without stopping the line or changing the product composition.

Przedstawiono fizyczne i chemiczne podstawy zastosowania znaczników izotopowych do kontroli szczelności i lokalizacji wycieków w rurociągach podziemnych. Metoda znacznikowa odznacza się wysoką czułością oraz łatwością stosowania. Przeprowadzenie badań nie jest czasochłonne oraz nie wymaga zatrzymywania naturalnego przebiegu procesu czy zmiany składu produktu. Jako radioznacznika używano bromku metylu - wytwarzanego w specjalnym generatorze - znakowanego 82Br. Minimalna oznaczona wielkość wycieku wynosi jeden litr na godzinę. Prezentowane badania szczelności rurociągów naftowych były pierwszymi pomiarami tego typu, przeprowadzonymi w Iranie. Aktualnie Iran dysponuje zespołem ludzkim i aparaturą pozwalającą na prowadzenie tego typu pomiarów dla rurociągów: 8-,10-,16- i 18-calowych.