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Number of results: 6
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Abstract

The aim of the study was to determine the configuration of pathologic audiograms in patients with excessive noise exposure, and to calculate the frequency of notches in the audiogram in patients with and without excessive noise exposure by avoiding the effect of age-related hearing loss. We have analyzed 514 audiograms of 257 patients aged between 20 to 50 years: 240 patients (mean age of 38.7 years) with excessive noise exposure and 17 patients (mean age of 41.2 years) with notches in the audiogram, but without a history of excessive noise exposure. For statistical data analysis we have used the Chi-square test and Fisher exact test with the level of significance p < 0.05. Pathologic audiograms were classified into five different types: Slope at 4000 Hz (0.8%), Slope at 2000 Hz (15.1%), Notch at 4000 Hz (67.4%), Notch at 2000 Hz (0.8%), Flat (8.9%), and 7% were out of this classification. A total of 190 (79.2%) patients with excessive noise exposure had a notch in the audiogram. Left ear notches were the most common. Among the patients with notched audiograms, 91.8% had a history of excessive noise exposure, either occupational or nonoccupational, and 8.2% did not report any excessive noise exposure.
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Authors and Affiliations

Lidija Ristovska
Zora Jachova
Nikica Atanasova
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Abstract

In this paper, a conventional mushroom-type EBG unit cell is made compact by etching a C-slot at its conducting surface. Further, the C-slotted mushroom-type EBG unit cell is coupled with a microstrip line using a novel groove-coupling technique to design a notch filter. The arrangement has achieved in the reduction of the electrical size of the mushroom type EBG unit cell by 46:15% and create a stop band suppression of -12 dB. The proposed EBG is applied to notch a narrow band centered at 5:2 GHz along with an ultra-wideband antenna. The far field gain of the antenna is suppressed by -5:8 dBi along the direction of its major lobe at 5:2 GHz. The overall size of the antenna system is 19x27x1:6mm3 which is compact. The performance of the antenna is validated from the simulation and measured results.

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Authors and Affiliations

Kumaresh Sarmah
Sivaranjan Goswami
Angana Sarma
Sunandan Baruah
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Abstract

In this paper a band notch characteristics reconfigurable UWB leaf shape monopole antenna is reported. The proposed antenna size is 42×32×1.6 mm3 and simulated S11 -10dB impedance bandwidth is from 2.1 to 13.0 GHz. The notch bands are embodied into the designed antenna to suppress Bluetooth and WiFi bands from 2.3-2.7 GHz and 4.6-5.3 GHz. The PIN Diode is loaded to slot on the DGS to achieve notch bands. It has 4.48dB and 1.7dB gain achieved when diode ON and OFF condition. Further, it encompasses a bio-inspired leaf shape patch having high feasibility for deployment in secret and military purposes.
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Authors and Affiliations

Pachiyaannan Muthusamy
1
Srikanta Nallapaneni
2
Krishna Chaitanya Perumalla
2
Bharghava Punna
2

  1. Department of Electronics and Communication Engineering, Advanced RF Microwave & Wireless Communication Laboratory, Vignan’s Foundation for Science Technology and Research (Deemed to be University), Andhra Pradesh, India
  2. Department of Electronics and CommunicationEngineering, Advanced RF Microwave & Wireless CommunicationLaboratory, Vignan’s Foundation for Science Technology and Research(Deemed to be University), Andhra Pradesh, India
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Abstract

The article presents an analysis of the change in air voids in asphalt mixtures subjected to fatigue tests at three temperatures of 0°C, 10°C and 25°C. The X-ray computerized tomography imaging method, XCT, was used to identify the air voids in the samples. The research allowed to determine changes in the content of air voids in subsequent fatigue cycles in the sample area. The relationship between air voids volume and the stiffness modulus value was also determined during fatigue for three temperatures. The largest changes were found in samples with notches at 0°C. The analysis of the change in the content of air voids showed that the micro-cracking nucleation processes develop with the number of fatigue cycles. Using the numerical model finite element method we determined the distribution and change in fatigue damage in the extreme areas of the sample during various stages of fatigue. We found clear relationship between the damage and the increased content of air voids.

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Authors and Affiliations

P. Mackiewicz
A. Szydło
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Abstract

Many studies have been developed aiming to improve digital filters realizations, recurring to intricate structures and analyzing probabilistically the error's behavior. The work presented in this paper analyzes the feasibility of fixed-point implementation of classical infinite impulse response notch filters: Butterworth, Chebyshev I and II, and elliptic. To scrutinize the deformations suffered for distinct design specifications, it is assessed: the effect of the quality factor and normalized cut-off frequency, in the number of significant bits necessary to represent the filter's coefficients. The implications brought to FPGA implementation are also verified. The work focuses especially on the implementation of power line notch filters used to improve the signal-to-noise ratio in biomedical signals. The results obtained, when quantizing the digital notch filters, show that by applying second-order sections decomposition, low-order digital filters may be designed using only part of double precision capabilities. High-order notch filters with harsh design constraints are implementable using double precision, but only in second-order sections. Thus, it is revealed that to optimize computation time in real-time applications, an optimal digital notch filter implementation platform should have variable arithmetic precision. Considering these implementation constraints, utmost operation performance is finally estimated when implementing digital notch filters in Xilinx Virtex-5 field-programmable gate arrays. The influence of several design specifications, e.g. type, and order, in the filter's behavior was evaluated, namely in regard to order, type, input and coefficient number of bits, quality factor and cut-off frequency. Finally the implications and potential applications of such results are discussed.
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Authors and Affiliations

Eduardo Pinheiro
Octavian Postolache
Pedro Girão
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Abstract

The fracture reason of steel wire cable is complex, and the corrosion and local bending effect of anchorage end of steel wire cable under tension are one of the main factors. Taking the steel wire of an arch bridge cable as the research object, the notch method was used to simulate the corrosion pits on the surface of the steel wire, and the tension and bending mechanical properties of the high strength notched steel wire were tested. The bending finite element model of the high strength steel wire was established by ANSYS WORKBENCH, and the tension and bending mechanical properties of the notched steel wire under different vertical loads and pretension were studied. The test and calculation results show that the test data are close to the finite element calculation results and the variation law is consistent. Under the same vertical load, the deformation of steel wire notch decreases with the increase of pretension; The stress at the bottom of the notch is the largest at 180˚ direction and the smallest at 90˚ direction of the vertical load.Under the same vertical load and pretension, the stress of spherical shape at the notch is the largest, followed by ellipsoid shape, and groove shape is the smallest, and there is a high stress zone at the edge of groove shape. When the pretension is applied, the initial stress increases with the increase of pretension, while the stress at the notch caused by bending decreases with the increase of pretension.
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Authors and Affiliations

Hongyu Fei
1
ORCID: ORCID
Quansheng Sun
1
ORCID: ORCID
Jianxi Yang
1
ORCID: ORCID

  1. School of Civil Engineering, Northeast Forestry University, 150040 Harbin, China

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