scholarly journals Experimental Investigation of Flood Energy Dissipation through Embankment Followed by Emergent Vegetation

2021 ◽  
Author(s):  
Afzal Ahmed ◽  
Manousos Valyrakis ◽  
Abdul Razzaq Ghumman ◽  
Ghufran Ahmed Pasha ◽  
Rashid Farooq
Keyword(s):  
Experimental Investigation ◽  
Energy Dissipation ◽  
Open Channel ◽  
Maximum Energy ◽  
Defense System ◽  
Maximum Increase ◽  
Defense Systems ◽  
Rigid Vegetation ◽  
Embankment Height ◽  
Vegetation Models

The combination of hard (artificial) and soft (natural) solutions i.e., composite defense systems against flooding and tsunami opens a new window for engineering innovation for researchers nowadays. In this study, the experimental investigation of flood energy dissipation phenomena through composite defense systems comprising of embankment and rigid vegetation models in an open channel flume, is conducted. The flow regime through the composite defense system is classified in two main types, which are further subdivided in two sub-categories. Various combinations of embankment and vegetation and spacing between embankment and vegetation are analyzed. Against the selected range of initial Froude numbers, three different sizes of embankment models, three spacings between the embankment and vegetation (Ldv) and vegetated corridors of two different porosities (PR), are tested to examine the effect of these three parameters on the characteristics of the generated hydraulic jumps and flood energy dissipation within the defense system. It is found that embankment size and vegetation porosity have a greater impact on flood energy dissipation while the selected range of Ldv is less effective. Amongst the assessed composite flood defense systems, the maximum energy dissipation (55%) is observed for the combination of maximum embankment height and vegetation porosity (93%). For fixed combinations of embankment size and Ldv, the maximum increase of energy dissipation (18%) is found for decreasing vegetation porosity from 97% to 93%.

scholarly journals Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 80
Author(s):  
Bo Zhang ◽  
Sizhi Zeng ◽  
Fenghua Tang ◽  
Shujun Hu ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Loading Rate ◽  
Effective Elastic Modulus ◽  
Maximum Energy ◽  
Numerical Results ◽  
Energy Dissipation Capacity

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.

scholarly journals Dependence of the energy efficiency of the acousto-optic modulator of terahertz radiation on the dimensions of the ultrasound transducer

2021 ◽  
Vol 2091 (1) ◽  
pp. 012011
Author(s):  
P A Nikitin ◽  
A K Nikitin
Keyword(s):  
Energy Efficiency ◽  
Experimental Investigation ◽  
Terahertz Radiation ◽  
Sulfur Hexafluoride ◽  
Maximum Energy ◽  
Ultrasound Transducer ◽  
Optimal Size ◽  
Acousto Optic Interaction ◽  
Acousto Optic Modulator ◽  
Ultrasound Power

Abstract The paper presents results of experimental investigation of an acousto-optic modulator of terahertz radiation based on liquefied sulfur hexafluoride. It was found that the intensity of diffracted radiation at a fixed ultrasound power depends on the dimensions of the ultrasound transducer. The optimal size of the ultrasound transducer in the direction orthogonal to the plane of the acousto-optic interaction was determined, at which the maximum energy efficiency of the acousto-optic modulator was achieved.

scholarly journals Study of Mechanical Energy Dissipation by Normal and Decalcified Animals Bones

2019 ◽  
Vol 16 (1) ◽  
pp. 113-119
Author(s):  
Abdul Rauf ◽  
Syed Ismail Ahmad
Keyword(s):  
Energy Dissipation ◽  
Viscoelastic Properties ◽  
Applied Load ◽  
Mechanical Energy ◽  
Maximum Energy ◽  
Hysteresis Curve ◽  
Normal Bone ◽  
Dissipation Of Energy ◽  
Mechanical Energy Dissipation ◽  
Energy Dissipated

The energy dissipated properties of normal and decalcified femur, rib and scapula bones of animals ox and camel have been studied by uniform bending technique. A hysteresis curve has been observed between the elevation in bone and load applied. It is observed that the energy dissipated as calculated from the hysteresis loop for rib is more than that of femur and scapula of ox and camel. It has been observed that the dissipation of energy in normal bone is less than that of decalcified bone under the same condition of applied load. The highest energy dissipation was observed in case of rib bone of camel compared to that of any other bone, rib of camel and scapula of ox dissipates maximum energy than femur bones. The study suggests that this technique is simple, elegant and inexpensive besides accurate in determining viscoelastic properties of bone.

A Longitudinal Study of Cellular Changes in Experimental Otitis Media

1979 ◽  
Vol 87 (5) ◽  
pp. 685-700 ◽  
Author(s):  
Marcos V. Goycoolea ◽  
Michael M. Paparella ◽  
Anna Mary Carpenter ◽  
S. K. Juhn
Keyword(s):  
Longitudinal Study ◽  
Otitis Media ◽  
Experimental Animal ◽  
Middle Ear ◽  
Defense System ◽  
Tube Obstruction ◽  
Defense Systems ◽  
Cellular Changes ◽  
Staining Techniques ◽  
The Continuum

A longitudinal sequential study of otitis media in an experimental animal (cat) using eustachian tube obstruction was done. Fifty animals were used. The continuum of mucoperiosteal changes from one day to six months after obstruction revealed gradual changes that were similar for each animal. Stages were defined, and by using different staining techniques, including immunocytochemistry, an overall middle ear defense system was postulated and documented. Nonspecific as well as specific defense systems, including localized immunity, were described. Effusions were studied in a continuum, and their pathogenesis was discussed.

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