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To correlate headng impairment and simultaneous occupational exposure to noise and organic solvents, it was made a cross-sectional research in 140 workers from a paper factory's with more than five years in same factory job. Workers were distributed in three groups as follows: unexposed (n=43), exposed to noise (n=50) and exposed to noise and organic solvents (n=47). Medical examination included audiometry to look for hearing impairment. The risk of hypoacusia was greater in exposed workers than in unexposed ones. Exposure to noise longer than five years was related to Odds Ratio (OR)=11,85 (1,46-66.57) and a hearing impairment prevalence of 22%. Simultaneous occupational exposure to noise and solvents produced OR=14.4 (1.78-77.3) and 25.53% hypoacusia prevalence. For men exposed to noise and solvents, the risk of hearing impairment was 1,22 times greater than for workers exposed to noise only [OR=1.22 (0.43-3.43)]. It was determined that workers simultaneously exposed to noise and solvents had not a greater risk to suffer hearing impairment than those exposed only to noise. [ABSTRACT FROM AUTHOR]

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Copyright of Signo y Pensamiento is the property of Pontificia Universidad Javeriana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lámpsakos is the property of Fundacion Universitaria Luis Amigo, Facultad de Ingenierias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Semestre Económico is the property of Sello Editorial de la Universidad de Medellin and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Cuadernos de Vivienda y Urbanismo is the property of Pontificia Universidad Javeriana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Iberoamericana de Ingeniería Mecánica is the property of Editorial UNED and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Habanera de Ciencias Médicas is the property of Universidad de Ciencias Medicas de La Habana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of 3C Tecnologia is the property of Area de Innovacion y Desarrollo, SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper reports the main design elements of a programmable gain transimpedance amplifier (TIA) with a photodiode as sensor device. The photodiode and the TIA are part of the measurement system of a plate reader with two reading modes, absorbance and fluorescence. The photodiodes are one of the most used sensors in spectroscopy systems and TIA are fundamental for conditioning signals from such sensor block. An analysis of some aspects that must be considered in their design, such as bandwidth, gain, noise as well as the main sources of noise that affect their operation is done. An analysis of the stability of the system to ensure proper operation. Emphasis on the characteristics of the components used and detail some layout suggestions of printed circuit boards in order to minimize the leakage currents. The design presented is a novel and feasible alternative to maximize the dynamic range of measurement plate readers or other optical spectroscopy system designed and produced by the Cuban biopharmaceutical industry. [ABSTRACT FROM AUTHOR]

In this paper the performance of the he×agonal, rectangular, circular two-dimension constellations of four and si×teen symbols with optimum rotations, concatenated with a golden symbol interleaver for a channel with class A noise is studied. This channel presents a white noise in the background plus impulsive noise. The system proposed achieves a great improvement in the symbol error rate. The symbols error probability is reduced for at least in one order of magnitude of 1×10-2 and the bit error rate is diminished in an order of magnitude of 1×10-3 in comparison to when no concatenation is utilized. [ABSTRACT FROM AUTHOR]

Copyright of Direito da Cidade is the property of Editora da Universidade do Estado do Rio de Janeiro (EdUERJ) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Investigación Bibliotecológica is the property of UNAM, Centro Universitario de Investigaciones Bibliotecologicas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High Noise Levels are one of the environmental and occupational problems arising from petrochemical plants. Noise generated by the gas flow in pipes is caused by the high velocity and turbulence. Accessories such as valves, elbows, ejectors and restrictions can reach noise levels, capable of affecting the performance and health of workers in these areas. Petrochemical plants have strict safety regulations; they operate at high pressure and temperatures and have little space to spare. The solution to control noise levels is covering the surface of pipes according to critical frequencies and availability of materials on place. The choice of lagging material was done according to critical frequencies at each section of the line, to match higher values of acoustic Transmission loss (TL) with critical frequencies. Sound masking was considered, since it is a common phenomenon in these cases where there are several noise sources, some very close to each other, and with noise intensity fluctuation in more than 10 decibels. This makes difficult the perception of a lower noise source when it is close to another source with higher noise intensity. This paper presents results of two studies performed at a methanol synthesis plant in Venezuela, which shows the behavior of acoustic lagging in gas lines at different stages in the areas of compression, synthesis and reformation in the methanol plant. Results are compared with theoretically estimated levels. [ABSTRACT FROM AUTHOR]

Copyright of Ciencia en su PC is the property of Instituto de Informacion Cientifica y Tecnologica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Detecting windows or intervals of when a continuous process is operating in a state of steadiness is useful for long term monitoring and especially when steady-state models are being used to optimize the process or plant on-line. In this paper a method, which is called as sigma -- gamma, on moving windows based that improves significantly existent algorithms is presented. On the measurements, it combines algorithms based on standard deviation analysis with moving average method and it can be applied not only on measurements which have been corrupted by additive white noise; but also on time series which have been corrupted by additive colored noise. Its performance is evaluated by comparing with two very recent methods. For different levels and noise types, tests point out that proposed method offers a significantly reduction on Type I and Type II errors. The base time series for algorithm's testing are related with the essential waveform's response below electrical generation units' work. [ABSTRACT FROM AUTHOR]

This paper is related to the application of Artificial Neural Networks (ANN) for noise cancelation in electric digital signals. The use of ANN is a novel technique in noise reduction, which only needs the noisy version of the signal to obtain the clean one. In this work is employed a FIR Multilayer Perceptron network. First is applied a software approach in Matlab, where the network is trained, and it's designed a strategy to reach the optimal network for noise cancelation in two cases study: simulated noise in Matlab and noise obtained through a Data Acquisition System connected to a sensor. Good results were achieved in the cancelation of both noises. Second approach is used to describe the ANN in hardware. The optimal FIR Multilayer Perceptron architecture of Matlab is implemented in VHDL (Very High Speed Integrated Circuit Hardware Description Language) to download in a Xilinx XC3S1200E FPGA (Field Programmable Gate Array), setting as goal in the design highlight the parallelism of ANN operation. After been obtained the VHDL design, a noise cancelation application is simulated, with good results, considering the errors produced by the less accuracy of the numerical format of VHDL ANN. Finally the design is downloaded in the FPGA and is checked that works according to the results of the software approach. [ABSTRACT FROM AUTHOR]

Copyright of Nexus (1900-9909) is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Cuidarte is the property of Universidad de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The managers of environmental noise measurements in environmental control agencies, or in general every person that works in this subject have to think on the representativeness of the unit measurement time interval, and how to evaluate it in order to get good quality results regarding the unit measurement time without increasing the measurement costs. A methodology for deciding if a certain measuring time interval -in this case, fifteen (15) minutes- is representative of noise pressure levels occurring during one hour is proposed in this paper. This methodology allows optimizing the use of stationary sound level meters and proposes a strategy for reducing the costs of environmental noise measurements and of the designing of noise maps in general. [ABSTRACT FROM AUTHOR]

Copyright of Revista Tecno Lógicas is the property of Instituto Tecnologico Metropolitano and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the first part of this paper the basics of the estimation of the stochastic production function is discussed. In the second part an application of the former is presented aimed at the hierarquization of the educational institutions which depend of the District of Bogotá, according to a measure of the technical efficiency --using inputs to maximize the output. For the present, a Cobb-Douglas production function is assumed with a symmetric noise and a semi-normal efficiency perturbations. Using maximum likelihood the parameters are obtained and the efficiency for each institution is calculated. [ABSTRACT FROM AUTHOR]

The sampling points for the range devices, and in general for the 3D sensors, in the acquisition process, they are always affected by the noise due to the inherent limitations of the physical process of measure. The noise happens in form of atypical values, or in form of small deviations of the sampling points from the true surface. For this reason, some pre-processing type is required to obtain a model of valid surface from the group of physical measures. In this paper, three explored techniques are exposed to define a strategy of selection of representative points of a range image (random selection, SOM, k-means), with the purpose of reducing the noise of the data and later, to trace a triangular mesh to obtain an approximate fitting of the surface to model. [ABSTRACT FROM AUTHOR]

The foothills areas are characterized by low velocity shallow layers and rugged topopgraphy. Inside these stratas a coherent noise named back scattering is produced, that noise overlaps the waves comming from the deeper reflectors. In seismic sections of the colombian foothills this signal is observed, obscuring the subsurface image. A method to attenuate this signal is presented in this paper, the approach is based in the prediction of this noise and the posterior remotion from the seismic records. The shallow layer response is simulated through the numerical modeling in finite elements of the acustic wave propagation in a subsurface model. Lately, the shallow layer response is subtracted trace by trace from the synthetic record, getting a high noise's attenuation in the shot. We present results obtained by synthetic data modeling. [ABSTRACT FROM AUTHOR]

A phenomenological (termohydraulic-neutronic) model is presented in this paper. It allows the description of the temperature fluctuation field propagation in a PWR. In the model it is considered some different kinds of noise sources, but the related to temperature fluctuation has been considered as the dominant one. Possibilities for parameter estimation application of the model are discussed in details. One expression for temperature reactivity coefficient estimation --parameter related to the safe work of the reactor-- has been obtained and commented. The reported results from the model, has been compared with noise measurements performed in 1986-1987 at the second unit of Paks nuclear power plant in Hungary. The good agreements of results validated the developed model. The described method can lye applied to on-line monitoring of this parameter. [ABSTRACT FROM AUTHOR]

In the present paper the step response method for system time constant calculations is described, revealing the connections between auto-regression coefficients and transient functions for a given system. The general calculational results obtained through this method (ARSTEP algorithm) for thermocouples, ionization chambers, and self-powered detectors used in nuclear power plants are given. The typical transfer function for these detectors and for the physical system described by means of a third order differential equation, as well as transfer function for dynamical processes of reactor core is found. On these basis, and with the aim to made it useful also for the neutronical sensors, a new algorithm for improving the ARSTEP code system is proposed. [ABSTRACT FROM AUTHOR]

This paper examines the main steps of the noise analysis technique implementation in our country from 1988. The review identifies two main areas: improvements of nuclear power plant operational surveillance techniques and non-nuclear industrial application. Some of the on-going research programs including projects on noise analysis instrumentation developments at the Higher Institute for Nuclear Sciences and Technology are also reported. [ABSTRACT FROM AUTHOR]

Copyright of Semestre Económico is the property of Sello Editorial de la Universidad de Medellin and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ingeniería y Competitividad is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)