The aim of the study was to examine the relationship between tinnitus pitch and maximum hearing loss, frequency range of hearing loss, and the edge frequency of the audiogram, as well as, to analyze tinnitus loudness at tinnitus frequency and normal hearing frequency.
The study included 212 patients, aged between 21 to 75 years (mean age of 54.4 ± 13.5 years) with chronic subjective tinnitus and sensorineural hearing loss. For the statistical data analysis we used Chisquare test and Fisher’s exact test with level of significance p < 0:05.
Tinnitus pitch corresponding to the frequency range of hearing loss, maximum hearing loss and the edge frequency was found in 70.8%, 37.3%, and 16.5% of the patients, respectively. The majority of patients had tinnitus pitch from 3000 to 8000 Hz corresponding to the range of hearing loss (p < 0:001). The mean tinnitus pitch was 3545 Hz ± 2482. The majority (66%) of patients had tinnitus loudness 4–7 dB SL. The mean sensation level at tinnitus frequency was 4.9 dB SL ± 1.9, and 13 dB SL ± 2.9 at normal hearing frequency.
Tinnitus pitch corresponded to the frequency range of hearing loss in majority of patients. There was no relationship between tinnitus pitch and the edge frequency of the audiogram. Loudness matching outside the tinnitus frequency showed higher sensation level than loudness matching at tinnitus frequency.
The association of phytoplasma was investigated in sand olive [Dodonaea viscosa ssp. Angustifolia (L. f.) J.G. West], cowpea [Vigna unguiclata (L.)] Wap and alfalfa (Medicago sativa L.) plants exhibiting witches broom, fasciation and little leaf symptoms, respectively. Sequence analysis of ~1.7 kb DNA fragments amplified by P1/P7 primer set confirmed the association of ‘Candidatus Phytoplasma aurantifolia’ within symptomatic alfalfa, while ‘Ca. Phytoplasma cynodontis’ was associated within cowpea and sand olive.
The research paper presents the results of hydraulic conductivity, pore structure, phase composition and microstructural tests of hardening slurries prepared using Portland cement, bentonite, water and fluidized-bed ashes coming from hard coal and lignite combustion. The slurries were subjected to long-term (210 days) exposure to the filtering action of an environment strongly aggressive to a cement binder. A sulphate solution 2- with sodium content of SO4 2- = 6700 mg/l was applied, which modelled sulphate aggression. The comparative base were samples subjected to filtration in tap water (neutral environment).
The test covered dependencies between hydraulic conductivity k10 (filtration coefficient) and the parameters characterizing porous structure in the slurry, as well as the impact of an aggressive medium on slurry tightness (its porosity and hydraulic conductivity). Changes in the phase composition and slurry microstructure were analysed in terms of its corrosion resistance to the action of sulphate aggression.
Observations from other researchers have been confirmed that the use of fluidized fly-ash addition has a positive effect on increasing the resistance of cement matrix exposed to sulphate aggressiveness.
The compactness of dimension stone blocks was previously controlled through various methods that were partially based on personal experiences, acoustic and visual observance of materials. With the development of technology, the ultrasonic pulse method is frequently used for the examination of stone test pieces and with an analysis of acquired data through the tomography method, the compactness is determined. The monolith stone blocks that are found at a site contain hidden discontinuities. The technique of data acquisition and the use of various instruments enable a good overview of the block interior. With an increased number of measurements, a suitable classification is prepared that helps reduce modification costs and increases the quality of stone blocks. The control methodology of compactness is based on the passage of longitudinal waves through the stone block without damaging the block during control. High differences in speed show irregularities in the material. With the observation system, we can prepare a tomography of the measured profiles that show us the locations of irregularities that should be observed more closely. During in situ measurements, the data for comparison with measured results are acquired. Determination of critical locations is of extreme importance before the processing of the block into smaller stone products or during the reconstruction of older stone elements or sculptures. The purpose of “in situ” measurements is to prepare a simple and fast method for the evaluation of materials compactness and for production work.
It can be expected that there is a considerable correlation between combustion air flow rate and the concentrations of carbon monoxide, hydrocarbons and nitrogen oxide in the flue gas. The influence of temperature and oxygen concentration in the combustion zone on the concentrations of carbon monoxide, hydrocarbons and nitrogen oxide in the flue gas, for high and low combustion air flow, was analysed. Oxygen concentration for which the concentration of carbon monoxide is the lowest was determined, as well as the mutual relation between carbon monoxide and nitrogen oxide concentration.
Cross layer cooperative protocol which exploits the benefits of physical layer cooperative communication, is one of the widely recognized MAC layer protocol design strategies for future wireless networks. This paper presents performance analysis of a cooperative mac and these performance parameters are compared those of the legacy IEEE 802.11 DCF MAC. Appropriate relay station selection is the main hurdle in designing efficient cooperative MAC protocol for wireless networks. This cooperative mac demonstrated that intermediate relay nodes themselves can initiate cooperation for relaying data frame to the receiver on behalf of the sender. This procedure makes the selection process of a “helper node” more distributed in nature as well as it contributes to increase throughput of a wireless network by reducing the overheads that are usually incurred in the helper selection process. It has been shown by thorough analytical analysis that the proposed cooperative MAC protocol offers higher throughput and lower frame transmission delay in both ideal and error prone wireless environment. These performance metrics are also evaluated while the wireless nodes are mobile as well.
Industrial applications require functional surfaces with a strictly defined micro-texture. Therefore engineered surfaces need to undergo a wide range of finishing processes. One of them is the belt grinding process, which changes the surface topography on a range of roughness and micro-roughness scales. The article describes the use of machined surface images in the monitoring process of micro-smoothing. Machined surface images were applied in the estimation of machined surface quality. The images were decomposed using two-dimensional Discrete Wavelet Transform. The approximation component was analyzed and described by the features representing the geometric parameters of image objects. Determined values of image features were used to create the model of the process and estimation of appropriate time of micro-smoothing.
An axially symmetric, gravity driven, steady flow of a grounded polar ice sheet with a prescribed temperature field is considered.
The ice is treated as an incompressible, non-linearly viscous, anisotropic fluid, the internal structure (fabric) of which evolves as ice descends from the free surface to depth in an ice sheet. The evolution of the ice fabric is described by an orthotropic constitutive law which relates the deviatoric stress to the strain-rate, strain, and three structure tensors based on the current (rotating) principal stretch axes. The solution of the problem is constructed as a leading-order approximation derived from asymptotic expansions in a small parameter that reflects the small ratio of stress and velocity gradients in the lateral direction of the ice sheet to those in the thickness direction. Numerical simulations of the flow problem have been carried out for various sets of rheological parameters defining the limit strength of the anisotropic fabric in ice. The results of calculations illustrate the influence of the ice anisotropy, basal melt conditions and temperature field in ice on the glacier thickness and lateral span, and on the depth profiles of the flow velocity.