25 research outputs found
Using negative velocity feedback controller to reduce the vibration of a suspended cable
The system of suspended cable with mixed excitation forces is controlled in this paper by using negative linear velocity feedback controller. The equations of motion of this system contain quadratic and cubic nonlinearities. The multiple scale perturbation technique is applied to determine the response of the nonlinear system near the simultaneous sub-harmonic and combined resonance case of this system. The stability of the obtained numerical solution is investigated using frequency response equations. The effect of different parameters on the vibrating system are investigated and reported
Contribution of 3-D electrical resistivity tomography for landmines detection
Landmines are a type of inexpensive weapons
widely used in the pre-conflicted areas in many countries
worldwide. The two main types are the metallic and nonmetallic
(mostly plastic) landmines. They are most commonly
investigated by magnetic, ground penetrating radar
(GPR), and metal detector (MD) techniques. These geophysical
techniques however have significant limitations in
resolving the non-metallic landmines and wherever the host
materials are conductive. In this work, the 3-D electric resistivity
tomography (ERT) technique is evaluated as an alternative
and/or confirmation detection system for both landmine
types, which are buried in different soil conditions and
at different depths. This can be achieved using the capacitive
resistivity imaging system, which does not need direct
contact with the ground surface. Synthetic models for each
case have been introduced using metallic and non-metallic
bodies buried in wet and dry environments. The inversion
results using the L1 norm least-squares optimization method
tend to produce robust blocky models of the landmine body.
The dipole axial and the dipole equatorial arrays tend to have
the most favorable geometry by applying dynamic capacitive
electrode and they show significant signal strength for data
sets with up to 5% noise. Increasing the burial depth relative
to the electrode spacing as well as the noise percentage in the
resistivity data is crucial in resolving the landmines at different
environments. The landmine with dimension and burial
depth of one electrode separation unit is over estimated while
the spatial resolutions decrease as the burial depth and noise
percentage increase
Using negative velocity feedback controller to reduce the vibration of a suspended cable
The system of suspended cable with mixed excitation forces is controlled in this paper by using negative linear velocity feedback controller. The equations of motion of this system contain quadratic and cubic nonlinearities. The multiple scale perturbation technique is applied to determine the response of the nonlinear system near the simultaneous sub-harmonic and combined resonance case of this system. The stability of the obtained numerical solution is investigated using frequency response equations. The effect of different parameters on the vibrating system are investigated and reported
Using negative velocity feedback controller to reduce the vibration of a suspended cable
The system of suspended cable with mixed excitation forces is controlled in this paper by using negative linear velocity feedback controller. The equations of motion of this system contain quadratic and cubic nonlinearities. The multiple scale perturbation technique is applied to determine the response of the nonlinear system near the simultaneous sub-harmonic and combined resonance case of this system. The stability of the obtained numerical solution is investigated using frequency response equations. The effect of different parameters on the vibrating system are investigated and reported
Groundwater resources assessment using integrated geophysical techniques in the southwestern region of Peninsular Malaysia.
Combined geophysical techniques such as multi-electrode resistivity, induced polarization, and borehole geophysical techniques were carried out on volcano-sedimentary rocks in the north of Gemas as part of the groundwater resource’s investigations. The result identifies four resistivity units: the tuffaceous mudstone, tuffaceous sandstone, the tuff bed, and the shale layer. Two types of aquifer systems in terms of storage were identified within the area: one within a fracture system (tuff), which is the leaky area through which vertical flow of groundwater occurs, and an intergranular property of the sandy material of the aquifer which includes sandstone and tuffaceous sandstone. The result also reveals that the aquifer occupies a surface area of about 3,250,555 m2 with a mean depth of 43.71 m and a net volume of 9.798 × 107 m3. From the approximate volume of the porous zone (28 %) and the total aquifer volume, a usable capacity of (274.339 ± 30.177) × 107 m3 of water in the study area can be deduced. This study provides useful information that can be used to develop a much broader understanding of the nature of groundwater potential in the area and their relationship with the local geology