Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Sensitivity


Synthesis and Characterization of Carbon Nanotubes Hydrogen Gas Sensor

Russul R .Ibraheem; Asama N. Naje

Engineering and Technology Journal, 2015, Volume 33, Issue 6, Pages 1059-1065

Two types of carbon nanotubes (MWCNTs and SWCNTs) films were used tofabricate hydrogen gas sensors. CNTs films were deposited on porous silicon substrate by the drop casting method. The two sensors showed high sensitivity to hydrogen gas at different concentrations. Experimental results indicated that the SWCNTs have a better performance than MWCNTs. The SWCNTs gas sensor shows high sensitivity at 150oC with 29sec response time, whereas MWCNTs gas sensor shows best sensitivity at 200oC with 24sec response time.

Design Aspects and Sensitivity Analysis of Tenth Order Active Bandpass Filter

Muneer A. Hashem; Wail I. Khalil; Raad B. Raheem

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 396-413

The design and sensitivity aspects of five stages tenth order active bandpass filter suitable for signal processing in electronic circuits are introduced. Simulation process performed is started by evaluating the voltage transfer function of the filter using the nodal approach to the second order activenet work model which represents each stage. The sensitivity analysis with respect to some parameter changes such as resonance frequency and quality factor is treated for proper choice of component values. The computational difficulties in the analog domain manipulations that arises through the cascaded arrangement of the filteris overcome by factorizing the terms in the denominator of the stated voltage transfer function with the aid of MATLAB 7.10.0(R2010a)software program. It was found that the increasing in the quality factor increases the magnitude, phase responses, higher deviation in magnitude sensitivity due to change in resonance frequency and lower frequency range due to change in quality factor. An increasing in the resonance frequency results in a better impulse and step response. The phase sensitivity due to change in resonance frequency shows that an increase in the quality factor gives higher deviation and this deviation is less in the sensitivity due to change in the quality factor. The simulation process of the circuit is done via the introduction of the Multisim software package version 9.0.155, offers good agreements with the results obtained.

Influence of Shape Design of MEMS (Micro-Cantilever Based Sensor) on High-Sensitivity

Ibtissam Mahdi Shihab

Engineering and Technology Journal, 2012, Volume 30, Issue 20, Pages 3581-3595

In this paper, a novel analysis was carried out on the biosensor microcantilevers
in order to increase the sensitivity of a micro- cantilever based
biosensor piezoresistive. Holes were made and compared with the basic
rectangular (R), triangular (T), and step(S) profile cantilever. Effect of changing
the micro-cantilevers profile and its cross-section shape was investigated. A finite
element ANSYS was used to analyze these models. The micro-cantilevers are
made of silicon with elastic modulus 130Gpa and poisson’s ratio 0.28. Several
cases were studied by making one, two and three holes in each biosensor
piezoresistive micro-cantilevers (rectangular (R), triangular (T), and step(S) profile
cantilever). Results showed that triangular micro-cantilever with two holes (T22)
has the better sensitivity, also showed T12 respectively 61.7% and 65% higher
sensitivity than R12, S12.

Sensitivity and Lower Limit Detection Determined of XRF for Copper and Zinc Suspended in lubricated Grease

Abdulhadi K. Judran AL-Ogaili

Engineering and Technology Journal, 2009, Volume 27, Issue 8, Pages 1554-1558

In this work different weight percent of copper and zinc powders of 20 ìm particle
size were blended carefully with grease , and the final weight of samples are 2 g . The
samples were placed in containers were made from tephlon of 2.5 cm as a diameter . The
bottom window of container was fitted with 6 ìm mylar film . The samples were
subjected to X- ray fluorescence to measure the Cu Ká and Zn Ká lines intensities .
Sensitivity (m) and Lower Limit Detection (LLD) were calculated and plotted against
the weight fraction for all samples .