WorldWideScience

Sample records for factors noise fuel

  1. Mechanism and optimization of fuel injection parameters on combustion noise of DI diesel engine

    Institute of Scientific and Technical Information of China (English)

    张庆辉; 郝志勇; 郑旭; 杨文英; 毛杰

    2016-01-01

    Combustion noise takes large proportion in diesel engine noise and the studies of its influence factors play an important role in noise reduction. Engine noise and cylinder pressure measurement experiments were carried out. And the improved attenuation curves were obtained, by which the engine noise was predicted. The effect of fuel injection parameters in combustion noise was investigated during the combustion process. At last, the method combining single variable optimization and multivariate combination was introduced to online optimize the combustion noise. The results show that injection parameters can affect the cylinder pressure rise rate and heat release rate, and consequently affect the cylinder pressure load and pressure oscillation to influence the combustion noise. Among these parameters, main injection advance angle has the greatest influence on the combustion noise, while the pilot injection interval time takes the second place, and the pilot injection quantity is of minimal impact. After the optimal design of the combustion noise, the average sound pressure level of the engine is distinctly reduced by 1.0 dB(A) generally. Meanwhile, the power, emission and economy performances are ensured.

  2. Critical Petermann K factor for intensity noise squeezing

    NARCIS (Netherlands)

    van der Lee, A.M.; van Druten, N.J.; van Exter, M.P.; Woerdman, J.P.; Poizat, J.P.; Grangier, P.

    2000-01-01

    We investigate the impact of the Petermann-excess-noise factor K >= 1 on the possibility of intensity noise squeezing of laser light below the standard quantum limit. Using an N-mode model, we show that squeezing is limited to a floor level of 2(K-1) times the shot noise limit. Thus, even a modest P

  3. Preliminary Mathematical Model for Jet Fuel Exacerbated Noise-Induced Hearing Loss

    Science.gov (United States)

    2013-01-01

    hearing loss . Noise alone induces hearing loss due to loss of hair cells in the cochlea, associated with oxidative stress. Jet fuel toxicity in association with noise may be at least partially explained by increased free radical production and oxidative stress at the cellular level, resulting in hair cell dysfunction and loss. This project combines a physiologically-based pharmacokinetic (PBPK) model to describe jet fuel component concentrations in the cochlea with pharmacodynamic (PD) models of free radical formation in the cochlea by both noise and

  4. Critical petermann K factor for intensity noise squeezing

    Science.gov (United States)

    van Der Lee AM; van Druten NJ; van Exter MP; Woerdman; Poizat; Grangier

    2000-11-27

    We investigate the impact of the Petermann-excess-noise factor K>/=1 on the possibility of intensity noise squeezing of laser light below the standard quantum limit. Using an N-mode model, we show that squeezing is limited to a floor level of 2(K-1) times the shot noise limit. Thus, even a modest Petermann factor significantly impedes squeezing, which becomes impossible when K>/=1.5. This appears as a serious limitation for obtaining sub-shot-noise light from practical semiconductor lasers. We present experimental evidence for our theory.

  5. [Noise--a stress factor in occupational and other environments].

    Science.gov (United States)

    Zober, A

    1984-03-01

    The effects of noise on health can be divided into aural effects and extraaural effects. The following review describes - after some historical remarks - first the physical and technical basis of noise analysis. The definition of "equivalent continuous sound level" (Lm) and "rating sound level" (Lr) is given. Extraaural noise effects mainly come from the environment (traffic noise, construction noise on building sites). One must distinguish physical and vegetative reactions. An important extraaural effect is the disturbance of sleep. The objectivation and quantification of extraaural effects of noise on health is very difficult because there exist a lot of disturbing factors. The most important aural effect of noise on health is the occupational hearing loss. To assess these effects, information about physiology, pathophysiology and clinical indications of noise induced labyrinthine deafness is necessary. As examples results of investigations into the effect of noise on arc welders, professional musicians and building workers are presented. Generation of noise should be minimised by technical methods, exposure to noise by personal protection. The methods for occupational medical check-up of the employment accident insurance fund are specially mentioned. The results of these preventive procedures can be seen in the decreasing numbers of occupational hearing loss.

  6. The noise factor in railway locomotives.

    Science.gov (United States)

    Rotter, T

    1982-09-01

    This article concerns the problem of acoustic work conditions on railway locomotives. The objective results of sonometric surveys in locomotive cabins are compared with subject data received from locomotive crews obtained by means of a specific questionnaire 'The Subjective Estimation of Noise'. The analysis touched 9 type of locomotives; steam, diesel and electric engines. We asked drivers of different age groups and with varying lengths of professional service for their opinions The aim of the investigation was to determine the following points: 1. to analyse the drivers' subjective estimation of the noise in the locomotive cabins; 2. to define length of time for which the driver remains under the influence of the noise after finishing work; 3. to investigate the question of perception and understanding of sounds and vocal signals used in the locomotive. These problems are a small part of the general plan to improve work conditions on the Polish National Railways.

  7. Jet transport energy management for minimum fuel consumption and noise impact in the terminal area

    Science.gov (United States)

    Bull, J. S.; Foster, J. D.

    1974-01-01

    Significant reductions in both noise and fuel consumption can be gained through careful tailoring of approach flightpath and airspeed profile, and the point at which the landing gear and flaps are lowered. For example, the noise problem has been successfully attacked in recent years with development of the 'two-segment' approach, which brings the aircraft in at a steeper angle initially, thereby achieving noise reduction through lower thrust settings and higher altitudes. A further reduction in noise and a significant reduction in fuel consumption can be achieved with the 'decelerating approach' concept. In this case, the approach is initiated at high airspeed and in a drag configuration that allows for low thrust. The landing flaps are then lowered at the appropriate time so that the airspeed slowly decelerates to V sub r at touchdown. The decelerating approach concept can be applied to constant glideslope flightpaths or segmented flightpaths such as the two-segment approach.

  8. Proton exchange membrane fuel cell diagnosis by spectral characterization of the electrochemical noise

    Science.gov (United States)

    Maizia, R.; Dib, A.; Thomas, A.; Martemianov, S.

    2017-02-01

    Electrochemical noise analysis (ENA) has been performed for the diagnosis of proton-exchange membrane fuel cell (PEMFC) under various operating conditions. Its interest is related with the possibility of a non-invasive on-line diagnosis of a commercial fuel cell. A methodology of spectral analysis has been developed and an evaluation of the stationarity of the signal has been proposed. It has been revealed that the spectral signature of fuel cell, is a linear slope with a fractional power dependence 1/fα where α = 2 for different relative humidities and current densities. Experimental results reveal that the electrochemical noise is sensitive to the water management, especially under dry conditions. At RHH2 = 20% and RHair = 20%, spectral analysis shows a three linear slopes signature on the spectrum at low frequency range (f power spectral density, calculated thanks to FFT, can be used for the detection of an incorrect fuel cell water balance.

  9. Effective Evaluation of the Noise Factor of Microchannel Plate

    Directory of Open Access Journals (Sweden)

    Honggang Wang

    2015-01-01

    Full Text Available To improve the noise performance of microchannel plate (MCP, we have presented a method using the sine random signals with Poisson distribution as the noise-excitation for electron source. By using this method, the effective evaluation of noise characteristics of MCP has been implemented through measuring and analyzing its noise factor. The results have demonstrated that the noise factor of filmed MCP is lower than 1.8. Additionally, as the open area ratio and the input electron energy are 72% and 400 eV, respectively, the noise characteristics of unfilmed MCP are improved evidently. Moreover, larger open area ratio, higher input electron energy, and higher voltage across the MCP all can reduce effectively the noise factor within a certain range. Meanwhile, the ion barrier film extends the life of image tube but at the cost of an increased noise factor. Therefore, it is necessary that a compromise between the optimum thickness of ion barrier film, open area ratio, input electron energy, and voltage across the MCP must be reached.

  10. The noise factor of receiver coil matching networks in MRI.

    Science.gov (United States)

    Cao, Xueming; Fischer, Elmar; Gruschke, Oliver; Korvink, Jan G; Hennig, Jürgen; Maunder, Adam M; De Zanche, Nicola; Zaitsev, Maxim

    2017-04-01

    In typical MRI applications the dominant noise sources in the received signal are the sample, the coil loop and the preamplifier. We hypothesize that in some cases (e.g. for very small receiver coils) the matching network noise has to be considered explicitly. Considering the difficulties of direct experimental determinations of the noise factor of matching networks with sufficient accuracy, it is helpful to estimate the noise factor by calculation. A useful formula of the coil matching network is obtained by separating commonly used coil matching network into different stages and calculating their noise factor analytically by a combination of the noise from these stages. A useful formula of the coil matching network is obtained. ADS simulations are performed to verify the theoretical predictions. Thereafter carefully-designed proof-of-concept phantom experiments are carried out to qualitatively confirm the predicted SNR behavior. The matching network noise behavior is further theoretically investigated for a variety of scenarios. It is found that in practice the coil matching network noise can be improved by adjusting the coil open port resonant frequency.

  11. JP-8 jet fuel can promote auditory impairment resulting from subsequent noise exposure in rats.

    Science.gov (United States)

    Fechter, Laurence D; Gearhart, Caroline; Fulton, Sherry; Campbell, Jerry; Fisher, Jeffrey; Na, Kwangsam; Cocker, David; Nelson-Miller, Alisa; Moon, Patrick; Pouyatos, Benoit

    2007-08-01

    We report on the transient and persistent effects of JP-8 jet fuel exposure on auditory function in rats. JP-8 has become the standard jet fuel utilized in the United States and North Atlantic Treaty Organization countries for military use and it is closely related to Jet A fuel, which is used in U.S. domestic aviation. Rats received JP-8 fuel (1000 mg/m(3)) by nose-only inhalation for 4 h and half of them were immediately subjected to an octave band of noise ranging between 97 and 105 dB in different experiments. The noise by itself produces a small, but permanent auditory impairment. The current permissible exposure level for JP-8 is 350 mg/m(3). Additionally, a positive control group received only noise exposure, and a fourth group consisted of untreated control subjects. Exposures occurred either on 1 day or repeatedly on 5 successive days. Impairments in auditory function were assessed using distortion product otoacoustic emissions and compound action potential testing. In other rats, tissues were harvested following JP-8 exposure for assessment of hydrocarbon levels or glutathione (GSH) levels. A single JP-8 exposure by itself at 1000 mg/m(3) did not disrupt auditory function. However, exposure to JP-8 and noise produced an additive disruption in outer hair cell function. Repeated 5-day JP-8 exposure at 1000 mg/m(3) for 4 h produced impairment of outer hair cell function that was most evident at the first postexposure assessment time. Partial though not complete recovery was observed over a 4-week postexposure period. The adverse effects of repeated JP-8 exposures on auditory function were inconsistent, but combined treatment with JP-8 + noise yielded greater impairment of auditory function, and hair cell loss than did noise by itself. Qualitative comparison of outer hair cell loss suggests an increase in outer hair cell death among rats treated with JP-8 + noise for 5 days as compared to noise alone. In most instances, hydrocarbon constituents of the fuel

  12. Analysis of power tiller noise using diesel-biodiesel fuel blends

    Directory of Open Access Journals (Sweden)

    N Keramat Siavash

    2015-09-01

    Full Text Available Introduction: There are several sources of noise in an industrial and agriculture environment. Machines with rotating or reciprocating engines are sound-producing sources. Also, the audio signal can be analyzed to discover how well a machine operates. Diesel engines complex noise SPL and sound frequency content both strongly depend on fuel combustion, which produces the so-called combustion noise. Actually, the unpleasant sound signature of diesel engines is due to the harsh and irregular self-ignition of the fuel. Therefore, being able to extract combustion noise from the overall noise would be of prime interest. This would allow engineers to relate the sound quality back to the combustion parameters. The residual noise produced by various sources, is referred to as mechanical noise. Since diesel engine noise radiation is associated with the operators’ and pedestrians’ discomfort, more and more attention to being paid to it. The main sources of noise generation in a diesel engine are exhaust system, mechanical processes such as valve train and combustion that prevail over the other two. In the present work, experimental tests were conducted on a single cylinder diesel engine in order to investigate the combustion noise radiation during stationary state for various diesel and biodiesel fuel blends. Materials and Methods: The engine used in the current study is an ASHTAD DF120-RA70 that is a single cylinder 4 stroke water cooled diesel engine and its nominal power is 7.5 hp at 2200 rpm. The experiment has been done at three positions (Left ear of operator, 1.5 and 7.5 meter away from exhaust based on ISO-5131 and SAE-J1174 standards. For engine speed measurement the detector Lurton 2364 was utilized with a measurement accuracy of 0.001 rpm. To obtain the highest accuracy, contact mode of detector was used. The engine noise was measured by HT157 sound level meter and was digitalized and saved with Sound View software. HT157 uses alow impedance

  13. Subcritical Noise Analysis Measurements with Fresh and Spent Research Reactor Fuels Elements

    Energy Technology Data Exchange (ETDEWEB)

    Valentine, T.E.; Mihalczo, J.T.; Kryter, R.C.; Miller, V.C.

    1999-02-01

    The verification of the subcriticality is of utmost importance for the safe transportation and storage of nuclear reactor fuels. Transportation containers and storage facilities are designed such that nuclear fuels remain in a subcritical state. Such designs often involve excess conservatism because of the lack of relevant experimental data to verify the accuracy of Monte Carlo codes used in nuclear criticality safety analyses. A joint experimental research program between Oak Ridge National Laboratory, Westinghouse Safety Management Solutions, Inc., and the University of Missouri was initiated to obtain measured quantities that could be directly related to the subcriticality of simple arrays of Missouri University Research Reactor (MURR) fuel elements. A series of measurement were performed to assess the reactivity of materials such as BORAL, stainless steel, aluminum, and lead that are typically used in the construction of shipping casks. These materials were positioned between the fuel elements. In addition, a limited number of measurements were performed with configurations of fresh and spent (irradiated) fuel elements to ascertain the reactivity of the spent fuel elements. In these experiments, fresh fuel elements were replaced by spent fuel elements such that the subcritical reactivity change could be measured. The results of these measurements were used by Westinghouse Safety Management Solutions to determine the subcriticality of MURR fuel elements isolated by absorbing materials. The measurements were interpreted using the MCNP-DSP Monte Carlo code to obtain the subcritical neutron multiplication factor k(sub eff), and the bias in K(sub eff) that are used in criticality safety analyses.

  14. Making Tensor Factorizations Robust to Non-Gaussian Noise

    CERN Document Server

    Chi, Eric C

    2010-01-01

    Tensors are multi-way arrays, and the Candecomp/Parafac (CP) tensor factorization has found application in many different domains. The CP model is typically fit using a least squares objective function, which is a maximum likelihood estimate under the assumption of i.i.d. Gaussian noise. We demonstrate that this loss function can actually be highly sensitive to non-Gaussian noise. Therefore, we propose a loss function based on the 1-norm because it can accommodate both Gaussian and grossly non-Gaussian perturbations. We also present an alternating majorization-minimization algorithm for fitting a CP model using our proposed loss function.

  15. Environmentally Responsible Aviation: Propulsion Research to Enable Fuel Burn, Noise and Emissions Reduction

    Science.gov (United States)

    Van Zante, Dale; Suder, Kenneth

    2015-01-01

    The NASA Environmentally Responsible Aviation (ERA) program is maturing technologies to enable simultaneous reduction of fuel burn, noise and emissions from an aircraft engine system. Three engine related Integrated Technology Demonstrations (ITDs) have been completed at Glenn Research Center in collaboration with Pratt Whitney, General Electric and the Federal Aviation Administration. The engine technologies being matured are: a low NOx, fuel flexible combustor in partnership with Pratt Whitney; an ultra-high bypass, ducted propulsor system in partnership with Pratt Whitney and FAA; and high pressure ratio, front-stage core compressor technology in partnership with General Electric. The technical rationale, test configurations and overall results from the test series in each ITD are described. ERA is using system analysis to project the benefits of the ITD technologies on potential aircraft systems in the 2025 timeframe. Data from the ITD experiments were used to guide the system analysis assumptions. Results from the current assessments for fuel burn, noise and oxides of nitrogen emissions are presented.

  16. Noise Factor and Antenna Gains in the Signal/Noise Equation for Over- the-Horizon Radar

    Science.gov (United States)

    1990-08-01

    August 1990 MTR1o989 AD-A23 1 203 M. M. Weiner Noise Factor and Antenna Gains in the Signal/Noise Equation for Over -the-Horizon Radar OTtOS ELECTE NW...I!D T:II.ASSI 1. E) August 1990 MTR10989 M. M. Weiner Noise Factor and Antenna Gains in the Signal/Noise Equation for Over -the-Horizon Radar CONTRACT...output terminals of the equivalent lossless receive antenna (J) s/b = sc (3-4) We further note that the receive antenna power gain g, is related to the

  17. Noise

    Science.gov (United States)

    Noise is all around you, from televisions and radios to lawn mowers and washing machines. Normally, you ... sensitive structures of the inner ear and cause noise-induced hearing loss. More than 30 million Americans ...

  18. Making tensor factorizations robust to non-gaussian noise.

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Eric C. (Rice University, Houston, TX); Kolda, Tamara Gibson

    2011-03-01

    Tensors are multi-way arrays, and the CANDECOMP/PARAFAC (CP) tensor factorization has found application in many different domains. The CP model is typically fit using a least squares objective function, which is a maximum likelihood estimate under the assumption of independent and identically distributed (i.i.d.) Gaussian noise. We demonstrate that this loss function can be highly sensitive to non-Gaussian noise. Therefore, we propose a loss function based on the 1-norm because it can accommodate both Gaussian and grossly non-Gaussian perturbations. We also present an alternating majorization-minimization (MM) algorithm for fitting a CP model using our proposed loss function (CPAL1) and compare its performance to the workhorse algorithm for fitting CP models, CP alternating least squares (CPALS).

  19. Signal and Noise scaling factors in digital holography

    CERN Document Server

    Lesaffre, Max; Atlan, Michael; Gross, Michel

    2013-01-01

    An experimental study on how reconstructed image signal and noise scale with acquisition and reconstruction parameters is proposed. Monte-carlo simulation is performed to emphasize that the measured noise is shot-noise.

  20. Energy efficient low-noise neural recording amplifier with enhanced noise efficiency factor.

    Science.gov (United States)

    Majidzadeh, V; Schmid, A; Leblebici, Y

    2011-06-01

    This paper presents a neural recording amplifier array suitable for large-scale integration with multielectrode arrays in very low-power microelectronic cortical implants. The proposed amplifier is one of the most energy-efficient structures reported to date, which theoretically achieves an effective noise efficiency factor (NEF) smaller than the limit that can be achieved by any existing amplifier topology, which utilizes a differential pair input stage. The proposed architecture, which is referred to as a partial operational transconductance amplifier sharing architecture, results in a significant reduction of power dissipation as well as silicon area, in addition to the very low NEF. The effect of mismatch on crosstalk between channels and the tradeoff between noise and crosstalk are theoretically analyzed. Moreover, a mathematical model of the nonlinearity of the amplifier is derived, and its accuracy is confirmed by simulations and measurements. For an array of four neural amplifiers, measurement results show a midband gain of 39.4 dB and a -3-dB bandwidth ranging from 10 Hz to 7.2 kHz. The input-referred noise integrated from 10 Hz to 100 kHz is measured at 3.5 μVrms and the power consumption is 7.92 μW from a 1.8-V supply, which corresponds to NEF = 3.35. The worst-case crosstalk and common-mode rejection ratio within the desired bandwidth are - 43.5 dB and 70.1 dB, respectively, and the active silicon area of each amplifier is 256 μm × 256 μm in 0.18-μm complementary metal-oxide semiconductor technology.

  1. The relation between psychoacoustical factors and annoyance under different noise reduction conditions for railway noise.

    Science.gov (United States)

    Kasess, Christian H; Maly, Thomas; Majdak, Piotr; Waubke, Holger

    2017-05-01

    The A-weighted sound pressure level (SPL) is commonly used to assess the effect of noise reduction measures on noise-induced annoyance. While for road traffic noise loudness seems to be a better descriptor of annoyance, for railway noise a systematic investigation seems to be lacking. Thus, in this study, the relation between annoyance and perceptually motivated descriptors was investigated for various conditions of binaural recordings of pass-bys of cargo and passenger trains. The conditions included free field and spectral mitigations caused by a 4 m high noise barrier, a 1 m high noise barrier close to the track, and rail dampers. Forty listeners performed a free magnitude estimation of annoyance for different presentation levels and the ratings were fit to various models. Further, level changes required to evoke a noticeable change in annoyance (annoyance thresholds) were acquired. The models based on the A-weighted SPL explained the ratings and thresholds better when the reduction measure was explicitly provided as a parameter. However, the optimal models were loudness-level-based models, which were able to better describe the annoyance, even independently of the reduction measure. Both experiments underline the effectiveness of loudness when describing the annoyance in the area of railway noise reduction.

  2. Noise and signal scaling factors in digital holography in weak illumination: relationship with shot noise.

    Science.gov (United States)

    Lesaffre, M; Verrier, N; Gross, M

    2013-01-01

    We have performed off-axis heterodyne holography with very weak illumination by recording holograms of the object with and without object illumination in the same acquisition run. We have experimentally studied how the reconstructed image signal (with illumination) and noise background (without) scale with the holographic acquisition and reconstruction parameters that are the number of frames and the number of pixels of the reconstruction spatial filter. The first parameter is related to the frequency bandwidth of detection in time, the second one to the bandwidth in space. The signal to background ratio varies roughly like the inverse of the bandwidth in time and space. We have also compared the noise background with the theoretical shot-noise background calculated by Monte Carlo simulation. The experimental and Monte Carlo noise background agree very well with each other.

  3. Geometric factors affecting noise suppresion and thrust loss of divergent-lobe supersonic jet noise suppressor

    Science.gov (United States)

    Huff, R. G.; Groesbeck, D. E.

    1973-01-01

    The thrust loss and noise suppression of a divergent-lobe supersonic jet noise suppressor were experimentally determined over a range of nozzle pressure ratios of 1.5 to 4.0. These small-scale cold flow tests were made to determine the effect on thrust and noise of: suppressor length, rearward facing step height, suppressor divergence angle, and ejector shroud length and location. Noise suppression was achieved at nozzle pressure ratios of 2.5 and greater. Maximum lobe jet noise attenuation of 15 db with thrust loss differences of 1.5 percent compared to the convergent nozzle were obtained at a nozzle pressure ratio of 3.5 with an ejector shroud two nozzle diameters long. Without the ejector the attenuation was 13 db with thrust loss differences of 11 percent. Short suppressors approximately one primary nozzle throat diameter long performed as well as longer suppressors. Rearward facing step height had a significant effect on noise suppression. Ejector shrouds two nozzle diameters in length are feasible.

  4. Evaluation of a Hydrogen Fuel Cell Powered Blended-Wing-Body Aircraft Concept for Reduced Noise and Emissions

    Science.gov (United States)

    Guynn, Mark D.; Freh, Joshua E.; Olson, Erik D.

    2004-01-01

    This report describes the analytical modeling and evaluation of an unconventional commercial transport aircraft concept designed to address aircraft noise and emission issues. A blended-wing-body configuration with advanced technology hydrogen fuel cell electric propulsion is considered. Predicted noise and emission characteristics are compared to a current technology conventional configuration designed for the same mission. The significant technology issues which have to be addressed to make this concept a viable alternative to current aircraft designs are discussed. This concept is one of the "Quiet Green Transport" aircraft concepts studied as part of NASA's Revolutionary Aerospace Systems Concepts (RASC) Program. The RASC Program was initiated to develop revolutionary concepts that address strategic objectives of the NASA Enterprises, such as reducing aircraft noise and emissions, and to identify advanced technology requirements for the concepts.

  5. Factors Affecting Noise Levels of High-Speed Handpieces

    Science.gov (United States)

    2012-06-01

    office communication and increase patient anxiety. Purpose: To determine if three noise-reducing techniques utilized in larger scale , non- dental...hearing loss may cause confusion, fear, and loneliness , and that sometimes hearing loss is accompanied by dizziness, which would be a handicap in the...employee noise exposures equal or exceed an 8- hour time-weighted average sound level (TWA) of 85 decibels measured on the A scale (slow response) or

  6. [Noise-reduction function and its affecting factors of urban plant communities in Shanghai].

    Science.gov (United States)

    Zhang, Qing-Fei; Zheng, Si-Jun; Xia, Lei; Wu, Hai-Ping; Zhang, Ming-Li; Li, Ming-Sheng

    2007-10-01

    The factor analysis on the relationships between excess noise attenuation (decrement after noise propagating 30 m) and 8 structural characteristics of 19 urban plant communities in Shanghai showed that all the plant communities had notable effects on reducing noise, and the noise attenuation ability of the communities was significantly higher than that of lawn (P attenuation ability, i.e., those of > or = 10 dB(A), 6-10 dB(A), and attenuation ability of the communities were leaf area index, average bifurcate height, average height, coverage, and average canopy diameter, and their correlation coefficients with noise attenuation were 0.343, 0.318, 0.285, 0.226 and 0.193, respectively. These five factors had a cumulative contribution rate of 65.47%, suggesting that they should be considered in stress when designing urban greenbelt for noise reduction.

  7. Noise-intolerance and state-dependent factors in patients with whiplash associated disorder

    NARCIS (Netherlands)

    Blokhorst, M.G.B.G.; Meeldijk, S.J.; Luijtelaar, E.L.J.M. van; Toor, T. van; Lousberg, R.; Ganzevles, P.

    2005-01-01

    An experiment was carried out in which the level of noise-intolerance in patients with a Whiplash Associated Disorder (WAD) was compared to healthy matched control subjects. In addition, the relationship between state-dependent factors (as headache, neck pain, fatigue and tension) and noise-intolera

  8. Background Noise Acceptance and Personality Factors Involved in Library Environment Choices by College Students

    Science.gov (United States)

    Gordon-Hickey, Susan; Lemley, Trey

    2012-01-01

    For decades, academic libraries made efforts to provide study environments differing in acoustic environment. The present study aimed to provide an evidence basis for this practice by comparing background noise acceptance and personality factors of two groups of college-aged students self identified as preferring quiet or background noise when…

  9. 77 FR 22067 - Publication of Inflation Adjustment Factor, Nonconventional Source Fuel Credit, and Reference...

    Science.gov (United States)

    2012-04-12

    ... Internal Revenue Service Publication of Inflation Adjustment Factor, Nonconventional Source Fuel Credit, and Reference Price for Calendar Year 2011 AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice. SUMMARY: Publication of the inflation adjustment factor, nonconventional source fuel credit, and...

  10. Empirical formulae for excess noise factor with dead space for single carrier multiplication

    KAUST Repository

    Dehwah, Ahmad H.

    2011-09-01

    In this letter, two empirical equations are presented for the calculation of the excess noise factor of an avalanche photodiode for single carrier multiplication including the dead space effect. The first is an equation for calculating the excess noise factor when the multiplication approaches infinity as a function of parameters that describe the degree of the dead space effect. The second equation can be used to find the minimum value of the excess noise factor for any multiplication when the dead space effect is completely dominant, the so called "deterministic" limit. This agrees with the theoretically known equation for multiplications less than or equal to two. © 2011 World Scientific Publishing Company.

  11. Determining the direction of causality between psychological factors and aircraft noise annoyance

    Directory of Open Access Journals (Sweden)

    Maarten Kroesen

    2010-01-01

    Full Text Available In this paper, an attempt is made to establish the direction of causality between a range of psychological factors and aircraft noise annoyance. For this purpose, a panel model was estimated within a structural equation modeling approach. Data were gathered from two surveys conducted in April 2006 and April 2008, respectively, among the same residents living within the 45 Level day-evening-night contour of Amsterdam Airport Schiphol, the largest airport in the Netherlands (n=250. A surprising result is that none of the paths from the psychological factors to aircraft noise annoyance were found to be significant. Yet 2 effects were significant the other way around: (1 from ′aircraft noise annoyance′ to ′concern about the negative health effects of noise′ and (2 from ′aircraft noise annoyance′ to ′belief that noise can be prevented.′ Hence aircraft noise annoyance measured at time 1 contained information that can effectively explain changes in these 2 variables at time 2, while controlling for their previous values. Secondary results show that (1 aircraft noise annoyance is very stable through time and (2 that changes in aircraft noise annoyance and the identified psychological factors are correlated.

  12. In Vitro Studies and Preliminary Mathematical Model for Jet Fuel and Noise Induced Auditory Impairment

    Science.gov (United States)

    2015-06-01

    impairment in stimulus encoding was exacerbated by low level (non-damaging) noise (8 kHz octave band at 85 dB sound pressure level) exposure. The results...and necrosis were enhanced when cells were exposed to JP-8 or hydrocarbons with oligomycin (in vitro noise surrogate). The PD model is designed to...death. The PD model will be parameterized using results from in vitro studies, and is designed to be interfaced with a physiologically-based

  13. Noise as an explanatory factor in work-related fatality reports.

    Science.gov (United States)

    Deshaies, Pierre; Martin, Richard; Belzile, Danny; Fortier, Pauline; Laroche, Chantal; Leroux, Tony; Nélisse, Hugues; Girard, Serge-André; Arcand, Robert; Poulin, Maurice; Picard, Michel

    2015-01-01

    Noise exposure in the workplace is a common reality in Québec, Canada as it is elsewhere. However, the extent to which noise acts as a causal or contributive factor in industrial work-related accidents has not been studied thoroughly despite its plausibility. This article aims to describe the importance or potential importance, during investigations looking into the specific causes of each work-related fatal accident, of noise as an explanatory factor. The written information contained in the accident reports pertaining to contextual and technical elements were used. The study used multiple case qualitative content analysis. This descriptive study was based on the content analysis of the 788 reports from the Commission de la santé et de la sécurité du travail du Québec [Workers' Compensation Board (WCB)] investigating the fatal work-related accidents between 1990 and 2005. The study was descriptive (number and percentages). Noise was explicitly stated as one of the explanatory factors for the fatal outcome in 2.2% (17/788) of the fatal accidents, particularly when the work involved vehicular movement or the need to communicate between workers. Noise was not typically considered a unique cause in the accident, notably because the investigators considered that the accident would have probably occurred due to other risk factors (for example, disregard of safety rules, shortcomings in work methods, and inadequate training). Noise is an important risk factor when communication is involved in work. Since noise is ubiquitous and may also interfere with vigilance and other risk factors for accidents, it may be a much more important contributing factor to accidents than is currently recognized.

  14. Transforming growth factor β1 inhibition protects from noise-induced hearing loss

    Directory of Open Access Journals (Sweden)

    Silvia eMurillo-Cuesta

    2015-03-01

    Full Text Available Excessive exposure to noise damages the principal cochlear structures leading to hearing impairment. Inflammatory and immune responses are central mechanisms in cochlear defensive response to noise but, if unregulated, they contribute to inner ear damage and hearing loss. Transforming growth factor ß (TGF-ß is a key regulator of both responses and high levels of this factor have been associated with cochlear injury in hearing loss animal models. To evaluate the potential of targeting TGF-ß as a therapeutic strategy for preventing or ameliorating noise-induced hearing loss, we studied the auditory function, cochlear morphology, gene expression and oxidative stress markers in mice exposed to noise and treated with TGF-ß1 peptidic inhibitors P17 and P144, just before or immediately after noise insult. Our results indicate that systemic administration of both peptides significantly improved both the evolution of hearing thresholds and the degenerative changes induced by noise-exposure in lateral wall structures. Moreover, treatments ameliorated the inflammatory state and redox balance. These therapeutic effects were dose-dependent and more effective if the TGF-ß1 inhibitors were administered prior to inducing the injury. In conclusion, inhibition of TGF-ß1 actions with antagonistic peptides represents a new, promising therapeutic strategy for the prevention and repair of noise-induced cochlear damage.

  15. Environmental Factors Having an Impact on the Noise Induced by Motor Vahicles

    Directory of Open Access Journals (Sweden)

    Rasa Akelaitytė

    2013-12-01

    Full Text Available The transport sector is rapidly developing industry in Lithuania. Over the past few years, a significant increase in motor vehicles on our roads can be noticed. Both light and heavy vehicles create economic benefits, and, at the same time, cause ecological and social problems such as noise, a growing number of accidents and environmental pollution. In order to reduce the rate of accidents, many places have been equipped with speed-limiting humps. However, the vehicles approaching them will increase noise levels. The article describes a calculation method of how to determine the influence of various factors caused by car noise. Reflections on the surface, the atmosphere and sound waves on road obstacles can increase or decrease sounds in the environment. The above introduced factors must be taken into account conducting noise measurement tests.Article in Lithuanian

  16. Identification of noise in linear data sets by factor analysis

    Energy Technology Data Exchange (ETDEWEB)

    Roscoe, B.A.; Hopke, Ph.K. (Illinois Univ., Urbana (USA))

    1982-01-01

    A technique which has the ability to identify bad data points, after the data has been generated, is classical factor analysis. The ability of classical factor analysis to identify two different types of data errors make it ideally suited for scanning large data sets. Since the results yielded by factor analysis indicate correlations between parameters, one must know something about the nature of the data set and the analytical techniques used to obtain it to confidentially isolate errors.

  17. [Noise as a stress factor for the onset of hearing disorders in workers using drilling equipment].

    Science.gov (United States)

    Nedić, O; Rodić-Strugar, J; Solak, Z; Filipović, D

    2001-01-01

    Noise is one of the commonest environmental pollutants and it is defined as a sound which bothers, irritates, which is unpleasant and can damage hearing. The degree of negative effects of noise depends on its intensity, spectrum of frequency, nature, duration of exposition and individual sensibility. This work is supposed to establish the degree of correlation between hearing damage and professional exposition to one of physical stressors of work environment--noise. Investigation regarding work conditions included intensity and frequency analysis of noise at workplaces. The examination sample included 101 workers of "NIS--Naftagas" section "Hidrosonda" employed as drilling workers. The control group consisted of 50 workers not exposed to noise or any other professional influences, like workers from the examination sample. The results on the observed workplaces show that noise is of high intensity and bad frequency spectrum. Exposition of workers to noise is a highly important factor for hearing damages (p = 0.002). The relative risk for hearing damage is four times greater in relation to the control group (odds ratio 4.1). Attributable fraction (preventive potential) of noise factor is 61%. Smoking associated with exposition to noise multiplies the risk of hearing damage (odds ratio 5.8) while with non-smokers the risk decreases (odds ratio 3.0). Professional hearing disorders occur slowly and increase with time spent at noisy workplaces. At the beginning it presents with buzzing in ears and dizziness followed by latent phase after which hearing disorders occur. Tone audiometry is used to register first signs of hearing loss, whereas manifestations in social contacts come later. Once diagnosed hearing disorders cannot be cured so a lot more care should be paid to this problem. It is necessary to provide adequate work conditions by applying appropriate technologies, tools, work organisation, personal protection equipment, as well as previous and periodical

  18. Identification of noise in linear data sets by factor analysis

    Energy Technology Data Exchange (ETDEWEB)

    Roscoe, B.A.; Hopke, P.K.

    1981-01-01

    The approach to classical factor analysis described in this paper, i.e. doing the analysis for varying numbers of factors without prior assumptions to the number of factors, prevents one from getting eroneous results by inherent computer code assumptions. Identification of a factor containing most of the variance of one variable with little variance of other variables, pinpoints a possible difficulty in the data, if the singularity has no obvious physical significance. Examination of the factor scores will determine whether the problem is isolated to a few samples or over all the samples. Having this information, one may then go back to the raw data and take the appropriate corrective action. Classical factor analysis has the ability to identify several types of errors in data after it has been generated. It is then ideally suited for scanning large data sets. The ease of the identification technique makes it a beneficial tool to use before reduction and analysis of large data sets and should, in the long run, save time and effort.

  19. Some factors to consider in handling and storing spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, W.J.

    1985-11-01

    This report includes information from various studies performed under the Wet Storage Task of the Behavior of Spent Fuel in Storage Project of the Commercial Spent Fuel Management (CSFM) Program at Pacific Northwest Laboratory. Wet storage experience has been summarized earlier in several other reports. This report summarizes pertinent items noted during FY 1985 concerning recent developments in the handling and storage of spent fuel and associated considerations. The subjects discussed include recent publications, findings, and developments associated with: (1) storage of water reactor spent fuel in water pools, (2) extended-burnup fuel, (3) fuel assembly reconstitution and reinsertion, (4) rod consolidation, (5) variations in the US Nuclear Regulatory Commission's definition of failed fuel, (6) detection of failed fuel rods, and (7) extended integrity of spent fuel. A list of pertinent publications is included.

  20. Identification of noise in linear data sets by factor analysis

    Energy Technology Data Exchange (ETDEWEB)

    Roscoe, B.A.; Hopke, P.K.

    1982-01-01

    With the use of atomic and nuclear methods to analyze samples for a multitude of elements, very large data sets have been generated. Due to the ease of obtaining these results with computerized systems, the elemental data acquired are not always as thoroughly checked as they should be leading to some, if not many, bad data points. It is advantageous to have some feeling for the trouble spots in a data set before it is used for further studies. A technique which has the ability to identify bad data points, after the data has been generated, is classical factor analysis. The ability of classical factor analysis to identify two different types of data errors make it ideally suited for scanning large data sets. Since the results yielded by factor analysis indicate correlations between parameters, one must know something about the nature of the data set and the analytical techniques used to obtain it to confidentially isolate errors.

  1. 78 FR 21008 - Publication of Inflation Adjustment Factor, Nonconventional Source Fuel Credit, and Reference...

    Science.gov (United States)

    2013-04-08

    .... 45K). The inflation adjustment factor and reference price are used to determine the credit allowable.... DATES: The 2012 inflation adjustment factor, nonconventional source fuel credit, and reference price... Internal Revenue Service Publication of Inflation Adjustment Factor, Nonconventional Source Fuel Credit...

  2. 76 FR 19524 - Publication of Inflation Adjustment Factor, Nonconventional Source Fuel Credit, and Reference...

    Science.gov (United States)

    2011-04-07

    .... 45K). The inflation adjustment factor and reference price are used to determine the credit allowable.... DATES: The 2010 inflation adjustment factor, nonconventional source fuel credit, and reference price... Internal Revenue Service Publication of Inflation Adjustment Factor, Nonconventional Source Fuel Credit...

  3. Impact of Bulldozer's Engine Load Factor on Fuel Consumption, CO2 Emission and Cost

    Directory of Open Access Journals (Sweden)

    V. Kecojevic

    2011-01-01

    Full Text Available Problem statement: Bulldozers consume a large amount of diesel fuel and consequently produce a significant quantity of CO2. Environmental and economic cost issues related to fuel consumption and CO2 emission represent a substantial challenge to the mining industry. Approach: Impact of engine load conditions on fuel consumption and the subsequent CO2 emission and cost was analyzed for Caterpillar bulldozers. Results were compared with the data on bulldozers' fuel consumption from an operating coal surface mine in the United States. Results: There is a strong linear correlation among power, fuel consumption and engine load factor. Reduction in load factor by 15% may significantly reduce the fuel consumption and the CO2 emission. Conclusion/Recommendation: Application of appropriate bulldozer's load factor may help mine operators manage fuel consumption, cost and environmental burden.

  4. Noise as an explanatory factor in work-related fatality reports

    Directory of Open Access Journals (Sweden)

    Pierre Deshaies

    2015-01-01

    The study used multiple case qualitative content analysis. This descriptive study was based on the content analysis of the 788 reports from the Commission de la santé et de la sécurité du travail du Québec [Workers′ Compensation Board (WCB] investigating the fatal work-related accidents between 1990 and 2005. The study was descriptive (number and percentages. Noise was explicitly stated as one of the explanatory factors for the fatal outcome in 2.2% (17/788 of the fatal accidents, particularly when the work involved vehicular movement or the need to communicate between workers. Noise was not typically considered a unique cause in the accident, notably because the investigators considered that the accident would have probably occurred due to other risk factors (for example, disregard of safety rules, shortcomings in work methods, and inadequate training. Noise is an important risk factor when communication is involved in work. Since noise is ubiquitous and may also interfere with vigilance and other risk factors for accidents, it may be a much more important contributing factor to accidents than is currently recognized.

  5. Railway noise annoyance and the importance of number of trains, ground vibration, and building situational factors.

    Science.gov (United States)

    Gidlöf-Gunnarsson, Anita; Ögren, Mikael; Jerson, Tomas; Öhrström, Evy

    2012-01-01

    Internationally accepted exposure-response relationships show that railway noise causes less annoyance than road traffic and aircraft noise. Railway transport, both passenger and freight transport, is increasing, and new railway lines are planned for environmental reasons. The combination of more frequent railway traffic and faster and heavier trains will, most probably, lead to more disturbances from railway traffic in the near future. To effectively plan for mitigations against noise and vibration from railway traffic, new studies are needed to obtain a better basis of knowledge. The main objectives of the present study was to investigate how the relationship between noise levels from railway traffic and general annoyance is influenced by (i) number of trains, (ii) the presence of ground borne vibrations, and (iii) building situational factors, such as orientation of balcony/patio and bedroom window. Socio-acoustic field studies were executed in residential areas; (1) with relatively intense railway traffic; (2) with strong vibrations, and; (3) with the most intense railway traffic in the country. Data was obtained for 1695 respondents exposed to sound levels ranging from L(Aeq,24h) 45 to 65 dB. Both number of trains and presence of ground-borne vibrations, and not just the noise level per se, are of relevance for how annoying railway noise is perceived. The results imply that, for the proportion annoyed to be equal, a 5 - 7 dB lower noise level is needed in areas where the railway traffic causes strong ground-borne vibrations and in areas with a very large number of trains. General noise annoyance was twice as high among residents in dwellings with balcony / patio oriented towards the railway and about 1.5 times higher among residents with bedroom windows facing the railway.

  6. Railway noise annoyance and the importance of number of trains, ground vibration, and building situational factors

    Directory of Open Access Journals (Sweden)

    Anita Gidlöf-Gunnarsson

    2012-01-01

    Full Text Available Internationally accepted exposure-response relationships show that railway noise causes less annoyance than road traffic and aircraft noise. Railway transport, both passenger and freight transport, is increasing, and new railway lines are planned for environmental reasons. The combination of more frequent railway traffic and faster and heavier trains will, most probably, lead to more disturbances from railway traffic in the near future. To effectively plan for mitigations against noise and vibration from railway traffic, new studies are needed to obtain a better basis of knowledge. The main objectives of the present study was to investigate how the relationship between noise levels from railway traffic and general annoyance is influenced by (i number of trains, (ii the presence of ground borne vibrations, and (iii building situational factors, such as orientation of balcony/patio and bedroom window. Socio-acoustic field studies were executed in residential areas; (1 with relatively intense railway traffic; (2 with strong vibrations, and; (3 with the most intense railway traffic in the country. Data was obtained for 1695 respondents exposed to sound levels ranging from L Aeq,24h 45 to 65 dB. Both number of trains and presence of ground-borne vibrations, and not just the noise level per se, are of relevance for how annoying railway noise is perceived. The results imply that, for the proportion annoyed to be equal, a 5 - 7 dB lower noise level is needed in areas where the railway traffic causes strong ground-borne vibrations and in areas with a very large number of trains. General noise annoyance was twice as high among residents in dwellings with balcony / patio oriented towards the railway and about 1.5 times higher among residents with bedroom windows facing the railway.

  7. Human response to wind turbine noise - perception, annoyance and moderating factors

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, Eja

    2007-05-15

    The aims of this thesis were to describe and gain an understanding of how people who live in the vicinity of wind turbines are affected by wind turbine noise, and how individual, situational and visual factors, as well as sound properties, moderate the response. Methods A cross-sectional study was carried out in a flat, mainly rural area in Sweden, with the objective to estimate the prevalence of noise annoyance and to examine the dose-response relationship between A-weighted sound pressure levels (SPLs) and perception of and annoyance with wind turbine noise. Subjective responses were obtained through a questionnaire (n = 513; response rate: 68%) and outdoor, A-weighted SPLs were calculated for each respondent. To gain a deeper understanding of the observed noise annoyance, 15 people living in an area were interviewed using open-ended questions. The interviews were analysed using the comparative method of Grounded Theory (GT). An additional cross-sectional study, mainly exploring the influence of individual and situational factors, was carried out in seven areas in Sweden that differed with regard to terrain (flat or complex) and degree of urbanization (n = 765; response rate: 58%). To further explore the impact of visual factors, data from the two cross-sectional studies were tested with structural equation modelling. A proposed model of the influence of visual attitude on noise annoyance, also comprising the influence of noise level and general attitude, was tested among respondents who could see wind turbines versus respondents who could not see wind turbines from their dwelling, and respondents living in flat versus complex terrain. Dose-response relationships were found both for perception of noise and for noise annoyance in relation to A-weighted SPLs. The risk of annoyance was enhanced among respondents who could see at least one turbine from their dwelling and among those living in a rural in comparison with a suburban area. Noise from wind turbines was

  8. Impact of noise and other factors on speech recognition in anaesthesia

    DEFF Research Database (Denmark)

    Alapetite, Alexandre

    2008-01-01

    effect, recognition rates for common noises (e.g. ventilation, alarms) are only slightly below rates obtained in a quiet environment. Finally, a redundant architecture succeeds in improving the reliability of the recognitions. Conclusion: This study removes some uncertainties regarding the feasibility...... operations. Objective: The aim of the experiment is to evaluate the relative impact of several factors affecting speech recognition when used in operating rooms, such as the type or loudness of background noises, type of microphone, type of recognition mode (free speech versus command mode), and type...... of training. Methods: Eight volunteers read aloud a total of about 3 600 typical short anaesthesia comments to be transcribed by a continuous speech recognition system. Background noises were collected in an operating room and reproduced. A regression analysis and descriptive statistics were done to evaluate...

  9. Consideration of some factors affecting low-frequency fuselage noise transmission for propeller aircraft

    Science.gov (United States)

    Mixson, J. S.; Roussos, L. A.

    1986-01-01

    Possible reasons for disagreement between measured and predicted trends of sidewall noise transmission at low frequency are investigated using simplified analysis methods. An analytical model combining incident plane acoustic waves with an infinite flat panel is used to study the effects of sound incidence angle, plate structural properties, frequency, absorption, and the difference between noise reduction and transmission loss. Analysis shows that these factors have significant effects on noise transmission but they do not account for the differences between measured and predicted trends at low frequencies. An analytical model combining an infinite flat plate with a normally incident acoustic wave having exponentially decaying magnitude along one coordinate is used to study the effect of a localized source distribution such as is associated with propeller noise. Results show that the localization brings the predicted low-frequency trend of noise transmission into better agreement with measured propeller results. This effect is independent of low-frequency stiffness effects that have been previously reported to be associated with boundary conditions.

  10. Removing non-stationary noise in spectrum sensing using matrix factorization

    Science.gov (United States)

    van Bloem, Jan-Willem; Schiphorst, Roel; Slump, Cornelis H.

    2013-12-01

    Spectrum sensing is key to many applications like dynamic spectrum access (DSA) systems or telecom regulators who need to measure utilization of frequency bands. The International Telecommunication Union (ITU) recommends a 10 dB threshold above the noise to decide whether a channel is occupied or not. However, radio frequency (RF) receiver front-ends are non-ideal. This means that the obtained data is distorted with noise and imperfections from the analog front-end. As part of the front-end the automatic gain control (AGC) circuitry mainly affects the sensing performance as strong adjacent signals lift the noise level. To enhance the performance of spectrum sensing significantly we focus in this article on techniques to remove the noise caused by the AGC from the sensing data. In order to do this we have applied matrix factorization techniques, i.e., SVD (singular value decomposition) and NMF (non-negative matrix factorization), which enables signal space analysis. In addition, we use live measurement results to verify the performance and to remove the effects of the AGC from the sensing data using above mentioned techniques, i.e., applied on block-wise available spectrum data. In this article it is shown that the occupancy in the industrial, scientific and medical (ISM) band, obtained by using energy detection (ITU recommended threshold), can be an overestimation of spectrum usage by 60%.

  11. Advanced Thermally Stable Coal-Derived Jet Fuels Compositional Factors Affecting Thermal Degradation of Jet Fuels

    Science.gov (United States)

    1992-12-01

    Hou, R.M. Copenhaver Fuel Science Program Department of Materials Science & Engineering The Pennsylvania State University 209 Academic Projects...AMMM, M. Sobbilif Y. LU. L N% R.M. Cap..kavw 7. PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES) .. PERFORMING ORGANIZATION Fuel Science Program REPORT...NUMBER Department of Materials Science & Engineering The Pennsylvania State University 209 Academic Projects Builiding University Park, PA 16802 9

  12. Strategic Noise Mapping of Herakleion: The Aircraft Noise Impact as a factor of the Int. Airport relocation

    Directory of Open Access Journals (Sweden)

    Vogiatzis Konstantinos

    2014-09-01

    Full Text Available In the framework of the European Directive 2002/49/EC, the city of Herakleion in Crete Island (Greece recently completed (2013 its Strategic Noise Map (SNM and relevant Noise Action Plan (NAP. Strategic noise mapping and action plans are important tools to define the main strategies to reduce noise exposure of residents and introduce and preserve "quite zones". Within this framework and as a part of the Herakleion city Strategic Noise Mapping general a specific analysis was introduced in the urban area of Alikarnassos (east part of the city adjacent to the International Airport “Nikos Kazantzakis”. The 2nd biggest airport in Greece, airport is proposed to be relocated in Kastelli area (some 37 km south of the Herakleion city centre, far away from dense populated areas, within the next decade but in the mean time, air traffic (take of, taxi and landing procedures, especially during the extended spring and summer period, are affecting the city. This paper analyzes the extended acoustic measurement monitoring program and the modelling of environmental noise levels within the city’s SNM introducing - state of the art - qualitative surveys on the sound perception and noise annoyance by the residents as well as in depth analysis of the urban and architectural tissue. All these results have been transcribed in several maps introducing a very comprehensive evaluation tool towards an efficient noise action plan leading to the eventual relocation of the airport. This paper presents the main results of this research aiming to the evaluation of the inffluence at the inhabitants’ sonic comfort from aircraft operation.

  13. FUEL CONSUMPTION: A MAJOR FACTOR INFLUENCING SALES OF NEW PERSONAL VEHICLES. EVIDENCE FROM ROMANIAN DATA

    Directory of Open Access Journals (Sweden)

    Daniela Pîrvu

    2013-03-01

    Full Text Available The purpose of this paper is to demonstrate empirically the validity of our supposition: the fuel consumption is currently the most important factor that influences sales of new personal vehicles. Factors that characterize an economical vehicle make 60 per cent of new personal vehicle buying decisions and the fuel consumption is the most important of these factors. The linear model for estimating the number of new personal vehicle registrations has good fit to the data.

  14. Factoring-based method for the design of a nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Guzman-Arriaga, Rafael; Espinosa-Paredes, Gilberto [Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186 Col. Vicentina, Mexico 09340, D. F. (Mexico)

    2010-05-15

    In this work a simple method for a fuel lattice design is presented. The method is focused on finding the radial distribution of the fuel rods having different fissile contents to obtain a prescribed neutron multiplication factor k{sub {infinity}} to a certain discharge burnup and to minimize the rod power peaking. This method is based on the factorization of the fissile content of each fuel bar and the performance of this novel method was demonstrated with a fuel design composed of enriched uranium for a typical boiling water reactor (BWR). The results show that the factoring-based method for the design of a nuclear fuel converges to a minimum rod power peaking and a prescribed k{sub {infinity}} in few iterations. A comparative analysis shows that the proposed method is more efficient than existing methods. (author)

  15. Shear wave velocity versus quality factor: results from seismic noise recordings

    Science.gov (United States)

    Boxberger, Tobias; Pilz, Marco; Parolai, Stefano

    2017-08-01

    The assessment of the shear wave velocity (vs) and shear wave quality factor (Qs) for the shallow structure below a site is necessary to characterize its site response. In the past, methods based on the analysis of seismic noise have been shown to be very efficient for providing a sufficiently accurate estimation of the vs versus depth at reasonable costs for engineering seismology purposes. In addition, a slight modification of the same method has proved to be able to provide realistic Qs versus depth estimates. In this study, data sets of seismic noise recorded by microarrays of seismic stations in different geological environments of Europe and Central Asia are used to calculate both vs and Qs versus depth profiles. Analogous to the generally adopted approach in seismic hazard assessment for mapping the average shear wave velocity in the uppermost 30 m (vs30) as a proxy of the site response, this approach was also applied to the quality factor within the uppermost 30 m (Qs30). A slightly inverse correlation between both parameters is found based on a methodological consistent determination for different sites. Consequently, a combined assessment of vs and Qs by seismic noise analysis has the potential to provide a more comprehensive description of the geological structure below a site.

  16. Estimation of random errors for lidar based on noise scale factor

    Science.gov (United States)

    Wang, Huan-Xue; Liu, Jian-Guo; Zhang, Tian-Shu

    2015-08-01

    Estimation of random errors, which are due to shot noise of photomultiplier tube (PMT) or avalanche photodiode (APD) detectors, is very necessary in lidar observation. Due to the Poisson distribution of incident electrons, there still exists a proportional relationship between standard deviation and square root of its mean value. Based on this relationship, noise scale factor (NSF) is introduced into the estimation, which only needs a single data sample. This method overcomes the distractions of atmospheric fluctuations during calculation of random errors. The results show that this method is feasible and reliable. Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB05040300) and the National Natural Science Foundation of China (Grant No. 41205119).

  17. Noise and Fano-factor Control in AC-Driven Aharonov-Casher Ring

    Directory of Open Access Journals (Sweden)

    Phillips A. H.

    2011-01-01

    Full Text Available The spin dependent current and Fano factor of Aharonov-Casher semiconducting ring is investigated under the effect of microwave, infrared, ultraviolet radiation and magnetic field. Both the average current and the transport noise (Fano factor characteristics are expressed in terms of the tunneling probability for the respective scattering channels. For spin transport induced by microwave and infrared radiation, a random oscillatory behavior of the Fano factor is observed. These oscillations are due to constructive and destructive spin interference effects. While for the case of ultraviolet radiation, the Fano factor becomes constant. This is due to that the oscillations has been washed out by phase averaging (i.e. ensemble dephasing over the spin transport channels. The present investigation is very important for quantum computing and information processing.

  18. Noise and Fano-Factor Control in AC-Driven Aharonov-Casher Ring

    Directory of Open Access Journals (Sweden)

    Zein W. A.

    2011-01-01

    Full Text Available The spin dependent current and Fano factor of Aharonov-Casher semiconducting ring is investigated under the effect of microwave, infrared, ultraviolet radiation and magnetic field. Both the average current and the transport noise (Fano factor characteristics are expressed in terms of the tunneling probability for the respective scattering channels. For spin transport induced by microwave and infrared radiation, a random oscillatory behavior of the Fano factor is observed. These oscillations are due to constructive and destructive spin interference effects. While for the case of ultraviolet radiation, the Fano factor becomes constant. This is due to that the oscillations has been washed out by phase averaging (i.e. ensemble dephasing over the spin transport channels. The present investigation is very important for quantum computing and information processing.

  19. Crucial factors influencing public acceptance of fuels treatments

    Science.gov (United States)

    Sarah. McCaffrey

    2009-01-01

    An important component of the wildland fire problem in the United States is the growing number of people living in high fire hazard areas. How people in these areas contribute to fire risk--or potentially decrease it--will be shaped by their attitudes and beliefs toward different fuel treatment approaches. Understanding the issues and concerns that influence public...

  20. Assessment of factors responsible for polymer electrolyte membrane fuel cell electrode performance by statistical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Velayutham, G.; Dhathathreyan, K.S.; Rajalakshmi, N. [Centre For Fuel Cell Technology, Project of ARC International, 120, Mambakkam Main Road, Medavakkam, Chennai 600 100 (India); Sampangi Raman, D. [Indian Statistical Institute, Nelson Manickam Road, Chennai 600 029 (India)

    2009-06-01

    The performance of the fuel cell electrode depends on many factors: types of materials and their properties, composition, process parameters and fuel cell operation conditions. In the present paper, cathode electrode performance in a PEM fuel cell as a function of Teflon concentration in the substrate materials and in micro-layer carbon, pore former in the micro-layer, amount of carbon used in the diffusion layer and Platinum and Nafion loading in the catalyst layer are studied. These six factors each at two levels are considered. A full factorial design would have required 2{sup 6}, i.e., 64 experiments to be carried out. With the use of Taguchi method, L{sub 12} designs, the number of experiments can be reduced to 12. The electrode current density values are taken as responses for the analysis. Statistical sensitivity analysis (ANOVA analysis) is used to compute the effects and the contributions of the various factors to the fuel cell electrode. Some graphic representations are employed in order to display the results of the statistical analysis made for different current values. The behavior of cathode PEM fuel cell electrode was studied using humidified hydrogen and compressed air. The present paper examines the six main factors and their levels responsible for altering the performance particularly when the fuel is operated under ambient pressure. (author)

  1. EFFECT SIGNIFICANCE ASSESSMENT OF THE THERMODYNAMICAL FACTORS ON THE SOLID OXIDE FUEL CELL OPERATION

    Directory of Open Access Journals (Sweden)

    V. A. Sednin

    2015-01-01

    Full Text Available Technologies of direct conversion of the fuel energy into electrical power are an upcoming trend in power economy. Over the last decades a number of countries have created industrial prototypes of power plants on fuel elements (cells, while fuel cells themselves became a commercial product on the world energy market. High electrical efficiency of the fuel cells allows predictting their further spread as part of hybrid installations jointly with gas and steam turbines which specifically enables achieving the electrical efficiency greater than 70 %. Nevertheless, investigations in the area of increasing efficiency and reliability of the fuel cells continue. Inter alia, research into the effects of oxidizing reaction thermodynamic parameters, fuel composition and oxidation reaction products on effectiveness of the solid oxide fuel cells (SOFC is of specific scientific interest. The article presents a concise analysis of the fuel type effects on the SOFC efficiency. Based on the open publications experimental data and the data of numerical model studies, the authors adduce results of the statistical analysis of the SOFC thermodynamic parameters effect on the effectiveness of its functioning as well as of the reciprocative factors of these parameters and gas composition at the inlet and at the outlet of the cell. The presented diagrams reflect dimension of the indicated parameters on the SOFC operation effectiveness. The significance levels of the above listed factors are ascertained. Statistical analysis of the effects of the SOFC functionning process thermodynamical, consumption and concentration parameters demonstrates quintessential influence of the reciprocative factors (temperature – flow-rate and pressure – flow-rate and the nitrogen N2 and oxygen O2 concentrations on the operation efficiency in the researched range of its functioning. These are the parameters to be considered on a first-priority basis while developing mathematical models

  2. Emission factors of carbonaceous particulate matter and polycyclic aromatic hydrocarbons from residential solid fuel combustions

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Guofeng [Jiangsu Academy of Environmental Science, Nanjing (China). Inst. of Atmospheric Sciences

    2014-07-01

    Emission inventory is basic for the understanding of environmental behaviors and potential effects of compounds, however, current inventories are often associated with relatively high uncertainties. One important reason is the lack of emission factors, especially for the residential solid fuel combustion in developing countries. In the present study, emission factors of a group of pollutants including particulate matter, organic carbon, elemental carbon (sometimes known as black carbon) and polycyclic aromatic hydrocarbons were measured for a variety of residential solid fuels including coal, crop straw, wood, and biomass pellets in rural China. The study provided a large number of emission factors that can be further used in emission estimation. Composition profiles and isomer ratios were investigated and compared so as to be used in source apportionment. In addition, the present study identified and quantified the influence of factors like fuel moisture, volatile matter on emission performance.

  3. Review of NO/sub x/ emission factors for stationary fossil fuel combustion sources. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Milligan, R.J.; Sailor, W.C.; Wasilewski, J.; Kuby, W.C.

    1979-09-01

    A review of recent NOx test data was performed, and summaries of emission factors presented for various types of stationary source combustion and for various fossil fuels. The effects of combustion modifications on NOx emissions are quantified. Background data are given to help the user determine the reliability of each factor in particular applications.

  4. Strong negative self regulation of prokaryotic transcription factors increases the intrinsic noise of protein expression.

    Science.gov (United States)

    Stekel, Dov J; Jenkins, Dafyd J

    2008-01-18

    Many prokaryotic transcription factors repress their own transcription. It is often asserted that such regulation enables a cell to homeostatically maintain protein abundance. We explore the role of negative self regulation of transcription in regulating the variability of protein abundance using a variety of stochastic modeling techniques. We undertake a novel analysis of a classic model for negative self regulation. We demonstrate that, with standard approximations, protein variance relative to its mean should be independent of repressor strength in a physiological range. Consequently, in that range, the coefficient of variation would increase with repressor strength. However, stochastic computer simulations demonstrate that there is a greater increase in noise associated with strong repressors than predicted by theory. The discrepancies between the mathematical analysis and computer simulations arise because with strong repressors the approximation that leads to Michaelis-Menten-like hyperbolic repression terms ceases to be valid. Because we observe that strong negative feedback increases variability and so is unlikely to be a mechanism for noise control, we suggest instead that negative feedback is evolutionarily favoured because it allows the cell to minimize mRNA usage. To test this, we used in silico evolution to demonstrate that while negative feedback can achieve only a modest improvement in protein noise reduction compared with the unregulated system, it can achieve good improvement in protein response times and very substantial improvement in reducing mRNA levels. Strong negative self regulation of transcription may not always be a mechanism for homeostatic control of protein abundance, but instead might be evolutionarily favoured as a mechanism to limit the use of mRNA. The use of hyperbolic terms derived from quasi-steady-state approximation should also be avoided in the analysis of stochastic models with strong repressors.

  5. Strong negative self regulation of Prokaryotic transcription factors increases the intrinsic noise of protein expression

    Directory of Open Access Journals (Sweden)

    Jenkins Dafyd J

    2008-01-01

    Full Text Available Abstract Background Many prokaryotic transcription factors repress their own transcription. It is often asserted that such regulation enables a cell to homeostatically maintain protein abundance. We explore the role of negative self regulation of transcription in regulating the variability of protein abundance using a variety of stochastic modeling techniques. Results We undertake a novel analysis of a classic model for negative self regulation. We demonstrate that, with standard approximations, protein variance relative to its mean should be independent of repressor strength in a physiological range. Consequently, in that range, the coefficient of variation would increase with repressor strength. However, stochastic computer simulations demonstrate that there is a greater increase in noise associated with strong repressors than predicted by theory. The discrepancies between the mathematical analysis and computer simulations arise because with strong repressors the approximation that leads to Michaelis-Menten-like hyperbolic repression terms ceases to be valid. Because we observe that strong negative feedback increases variability and so is unlikely to be a mechanism for noise control, we suggest instead that negative feedback is evolutionarily favoured because it allows the cell to minimize mRNA usage. To test this, we used in silico evolution to demonstrate that while negative feedback can achieve only a modest improvement in protein noise reduction compared with the unregulated system, it can achieve good improvement in protein response times and very substantial improvement in reducing mRNA levels. Conclusion Strong negative self regulation of transcription may not always be a mechanism for homeostatic control of protein abundance, but instead might be evolutionarily favoured as a mechanism to limit the use of mRNA. The use of hyperbolic terms derived from quasi-steady-state approximation should also be avoided in the analysis of stochastic

  6. Estimated Bounds and Important Factors for Fuel Use and Consumer Costs of Connected and Automated Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, T. S. [Argonne National Lab. (ANL), Argonne, IL (United States); Gonder, Jeff [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chen, Yuche [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lin, Z. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liu, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gohlke, D. [US Dept. of Energy, Washington, DC (United States)

    2016-11-01

    This report details a study of the potential effects of connected and automated vehicle (CAV) technologies on vehicle miles traveled (VMT), vehicle fuel efficiency, and consumer costs. Related analyses focused on a range of light-duty CAV technologies in conventional powertrain vehicles -- from partial automation to full automation, with and without ridesharing -- compared to today's base-case scenario. Analysis results revealed widely disparate upper- and lower-bound estimates for fuel use and VMT, ranging from a tripling of fuel use to decreasing light-duty fuel use to below 40% of today's level. This wide range reflects uncertainties in the ways that CAV technologies can influence vehicle efficiency and use through changes in vehicle designs, driving habits, and travel behavior. The report further identifies the most significant potential impacting factors, the largest areas of uncertainty, and where further research is particularly needed.

  7. A fuel-based approach for emission factor development for highway paving construction equipment in China.

    Science.gov (United States)

    Li, Zhen; Zhang, Kaishan; Pang, Kaili; Di, Baofeng

    2016-12-01

    The objective of this paper is to develop and demonstrate a fuel-based approach for emissions factor estimation for highway paving construction equipment in China for better accuracy. A highway construction site in Chengdu was selected for this study with NO emissions being characterized and demonstrated. Four commonly used paving equipment, i.e., three rollers and one paver were selected in this study. A portable emission measurement system (PEMS) was developed and used for emission measurements of selected equipment during real-world highway construction duties. Three duty modes were defined to characterize the NO emissions, i.e., idling, moving, and working. In order to develop a representative emission factor for these highway construction equipment, composite emission factors were estimated using modal emission rates and the corresponding modal durations in the process of typical construction duties. Depending on duty mode and equipment type, NO emission rate ranged from 2.6-63.7mg/s and 6.0-55.6g/kg-fuel with the fuel consumption ranging from 0.31-4.52 g/s correspondingly. The NO composite emission factor was estimated to be 9-41mg/s with the single-drum roller being the highest and double-drum roller being the lowest and 6-30g/kg-fuel with the pneumatic tire roller being the highest while the double-drum roller being the lowest. For the paver, both time-based and fuel consumption-based NO composite emission rates are higher than all of the rollers with 56mg/s and 30g/kg-fuel, respectively. In terms of time-based quantity, the working mode contributes more than the other modes with idling being the least for both emissions and fuel consumption. In contrast, the fuel-based emission rate appears to have less variability in emissions. Thus, in order to estimate emission factors for emission inventory development, the fuel-based emission factor may be selected for better accuracy.

  8. [Genetic factors in susceptibility to age- and noise-related hearing loss].

    Science.gov (United States)

    Sliwińiska-Kowalska, Mariola; Pawelczyk, Małgorzata; Kowalski, Tomasz Jarema

    2006-10-01

    Individual susceptibility to age-related hearing loss (AHL) and noise-induced hearing loss (NIHL) varies greatly, and this inter-individual variation is due to an interaction of environmental factors, individual factors, and susceptibility genes. Majority of studies on susceptibility genes for AHL and NIHL have been performed in mice model. These findings suggest the role of the same genes in the development of AHL and NIHL, the more so as the pathogenesis of both diseases is similar with a crucial role of oxidative stress. The alleles responsible for AHL have been localized to the chromosome 10 (Ahl gene). Ahl-/- mice develop hearing impairment at early age and are also oversensitive to noise. Ahl gene is a recessive gene and it is probably responsible for the synthesis of cell junction proteins. In mice ahl codes for cadherin (CDH) proteins. The cadherin of interest is named otocadherin or CDH23, and it is localized to the links between stereocilia of hair cells. A hypomorphic 753G>A single nucleotide polymorphism (SNP) in Cdh 23 is associated with AHL, and the 753A variant is also correlated with susceptibility to NIHL. An increased susceptibility to AHL and NIHL may rely on the SNPs of several other genes, including the groups of oxidative stress genes, K+ ions recycling genes, monogenic deafness genes (including Connexin 26 gene, which mutation is responsible for the most frequent hereditary deafness in Caucasians), as well as mitochondrial genes. Several oxidative stress enzyme (sod1-/-, gpx -/-) knock-out mice have been shown to be more susceptible to NIHL than wild strains. Current large-scale cohort studies on AHL and NIHL performed under the European projects in between-lab collaboration along with a dynamic progress in the field of genetics of deafness open up new opportunities to find human AHL and NIHL susceptibility genes and develop methods for AHUNIHL treatment.

  9. Land and Water Use, CO2 Emissions, and Worker Radiological Exposure Factors for the Nuclear Fuel Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Brett W Carlsen; Brent W Dixon; Urairisa Pathanapirom; Eric Schneider; Bethany L. Smith; Timothy M. AUlt; Allen G. Croff; Steven L. Krahn

    2013-08-01

    The Department of Energy Office of Nuclear Energy’s Fuel Cycle Technologies program is preparing to evaluate several proposed nuclear fuel cycle options to help guide and prioritize Fuel Cycle Technology research and development. Metrics are being developed to assess performance against nine evaluation criteria that will be used to assess relevant impacts resulting from all phases of the fuel cycle. This report focuses on four specific environmental metrics. • land use • water use • CO2 emissions • radiological Dose to workers Impacts associated with the processes in the front-end of the nuclear fuel cycle, mining through enrichment and deconversion of DUF6 are summarized from FCRD-FCO-2012-000124, Revision 1. Impact estimates are developed within this report for the remaining phases of the nuclear fuel cycle. These phases include fuel fabrication, reactor construction and operations, fuel reprocessing, and storage, transport, and disposal of associated used fuel and radioactive wastes. Impact estimates for each of the phases of the nuclear fuel cycle are given as impact factors normalized per unit process throughput or output. These impact factors can then be re-scaled against the appropriate mass flows to provide estimates for a wide range of potential fuel cycles. A companion report, FCRD-FCO-2013-000213, applies the impact factors to estimate and provide a comparative evaluation of 40 fuel cycles under consideration relative to these four environmental metrics.

  10. Observation of the Fundamental Nyquist Noise Limit in an Ultra-High $Q$-Factor Cryogenic Bulk Acoustic Wave Cavity

    CERN Document Server

    Goryachev, Maxim; van Kann, Frank; Galliou, Serge; Tobar, Michael E

    2014-01-01

    Thermal Nyquist noise fluctuations of high-$Q$ Bulk Acoustic Wave (BAW) cavities have been observed at cryogenic temperatures with a DC Superconducting Quantum Interference Device (SQUID) amplifier. High $Q$ modes with bandwidths of few tens of milliHz produce thermal fluctuations with a Signal-To-Noise ratio of up to 23dB. The estimated effective temperature from the Nyquist noise is in good agreement with the physical temperature of the device, confirming the validity of the equivalent circuit model and the non-existence of any excess resonator self-noise. The measurements also confirm that the quality factor remains extremely high ($Q>10^8$ at low order overtones) for very weak (thermal) system motion at low temperatures, when compared to values measured with relatively strong external excitation. This result represents an enabling step towards operating such a high-Q acoustic device at the standard quantum limit.

  11. Mutagenicity and Pollutant Emission Factors of Solid-Fuel Cookstoves: Comparison with Other Combustion Sources

    Science.gov (United States)

    Mutlu, Esra; Warren, Sarah H.; Ebersviller, Seth M.; Kooter, Ingeborg M.; Schmid, Judith E.; Dye, Janice A.; Linak, William P.; Gilmour, M. Ian; Jetter, James J.; Higuchi, Mark; DeMarini, David M.

    2016-01-01

    Background: Emissions from solid fuels used for cooking cause ~4 million premature deaths per year. Advanced solid-fuel cookstoves are a potential solution, but they should be assessed by appropriate performance indicators, including biological effects. Objective: We evaluated two categories of solid-fuel cookstoves for eight pollutant and four mutagenicity emission factors, correlated the mutagenicity emission factors, and compared them to those of other combustion emissions. Methods: We burned red oak in a 3-stone fire (TSF), a natural-draft stove (NDS), and a forced-draft stove (FDS), and we combusted propane as a liquified petroleum gas control fuel. We determined emission factors based on useful energy (megajoules delivered, MJd) for carbon monoxide, nitrogen oxides (NOx), black carbon, methane, total hydrocarbons, 32 polycyclic aromatic hydrocarbons, PM2.5, levoglucosan (a wood-smoke marker), and mutagenicity in Salmonella. Results: With the exception of NOx, the emission factors per MJd were highly correlated (r ≥ 0.97); the correlation for NOx with the other emission factors was 0.58–0.76. Excluding NOx, the NDS and FDS reduced the emission factors an average of 68 and 92%, respectively, relative to the TSF. Nevertheless, the mutagenicity emission factor based on fuel energy used (MJthermal) for the most efficient stove (FDS) was between those of a large diesel bus engine and a small diesel generator. Conclusions: Both mutagenicity and pollutant emission factors may be informative for characterizing cookstove performance. However, mutagenicity emission factors may be especially useful for characterizing potential health effects and should be evaluated in relation to health outcomes in future research. An FDS operated as intended by the manufacturer is safer than a TSF, but without adequate ventilation, it will still result in poor indoor air quality. Citation: Mutlu E, Warren SH, Ebersviller SM, Kooter IM, Schmid JE, Dye JA, Linak WP, Gilmour MI, Jetter

  12. Cultural and Demographic Factors Influencing Noise Exposure Estimates from Use of Portable Listening Devices in an Urban Environment

    Science.gov (United States)

    Fligor, Brian J.; Levey, Sandra; Levey, Tania

    2014-01-01

    Purpose: This study examined listening levels and duration of portable listening devices (PLDs) used by people with diversity of ethnicity, education, music genre, and PLD manufacturer. The goal was to estimate participants' PLD noise exposure and identify factors influencing user behavior. Method: This study measured listening levels of 160…

  13. Cultural and Demographic Factors Influencing Noise Exposure Estimates from Use of Portable Listening Devices in an Urban Environment

    Science.gov (United States)

    Fligor, Brian J.; Levey, Sandra; Levey, Tania

    2014-01-01

    Purpose: This study examined listening levels and duration of portable listening devices (PLDs) used by people with diversity of ethnicity, education, music genre, and PLD manufacturer. The goal was to estimate participants' PLD noise exposure and identify factors influencing user behavior. Method: This study measured listening levels of 160…

  14. Fast Prediction of Differential Mode Noise Input Filter Requirements for FLyback and Boost Unity Power Factor Converters

    DEFF Research Database (Denmark)

    Andersen, Michael Andreas E.

    1997-01-01

    Two new and simple methods to make predictions of the differential mode (DM) input filter requirements are presented, one for flyback and one for boost unity power factor converters. They have been verified by measurements. They give the designer the ability to predict the DM input noise filter...

  15. Epidemiology and Risk Factors for Leisure Noise-Induced Hearing Damage in Flemish Young Adults

    Directory of Open Access Journals (Sweden)

    Sofie Degeest

    2017-01-01

    Full Text Available Context: Young people regularly expose themselves to leisure noise and are at risk for acquiring hearing damage. Aims: The objective of this study was to compare young adults’ hearing status in relation to sociodemographic variables, leisure noise exposure and attitudes and beliefs towards noise. Settings and Design: A self-administered questionnaire regarding hearing, the amount of leisure noise exposure and attitudes towards noise and hearing protection as well as an audiological test battery were completed. Five hundred and seventeen subjects between 18 and 30 years were included. Subject and Methods: Hearing was evaluated using conventional audiometry, transient evoked and distortion product otoacoustic emissions. On the basis of their hearing status, participants were categorised into normal hearing, sub-clinical or clinical hearing loss. Statistical Analysis Used: Independent samples t-tests, chi-square tests and multiple regression models were used to evaluate the relation between groups based on hearing status, sociodemographics, leisure noise and attitudes towards noise. Results: Age was significantly related to hearing status. Although, the subjects in this study frequently participated in leisure activities, no significant associations between leisure noise exposure and hearing status could be detected. No relation with subjects’ attitudes or the use of hearing protection devices was found. Conclusions: This study could not demonstrate clinically significant leisure noise-induced hearing damage, which may lead to more non-protective behaviour. However, the effects of leisure noise may become noticeable over a long-term use since age was found to be related with sub-clinical hearing loss. Longitudinal studies are needed to evaluate the long-term effects of noise exposure.

  16. THE CALCULATION OF BURNABLE POISON CORRECTION FACTORS FOR PWR FRESH FUEL ACTIVE COLLAR MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Croft, Stephen [Los Alamos National Laboratory; Favalli, Andrea [Los Alamos National Laboratory; Swinhoe, Martyn T. [Los Alamos National Laboratory

    2012-06-19

    Verification of commercial low enriched uranium light water reactor fuel takes place at the fuel fabrication facility as part of the overall international nuclear safeguards solution to the civilian use of nuclear technology. The fissile mass per unit length is determined nondestructively by active neutron coincidence counting using a neutron collar. A collar comprises four slabs of high density polyethylene that surround the assembly. Three of the slabs contain {sup 3}He filled proportional counters to detect time correlated fission neutrons induced by an AmLi source placed in the fourth slab. Historically, the response of a particular collar design to a particular fuel assembly type has been established by careful cross-calibration to experimental absolute calibrations. Traceability exists to sources and materials held at Los Alamos National Laboratory for over 35 years. This simple yet powerful approach has ensured consistency of application. Since the 1980's there has been a steady improvement in fuel performance. The trend has been to higher burn up. This requires the use of both higher initial enrichment and greater concentrations of burnable poisons. The original analytical relationships to correct for varying fuel composition are consequently being challenged because the experimental basis for them made use of fuels of lower enrichment and lower poison content than is in use today and is envisioned for use in the near term. Thus a reassessment of the correction factors is needed. Experimental reassessment is expensive and time consuming given the great variation between fuel assemblies in circulation. Fortunately current modeling methods enable relative response functions to be calculated with high accuracy. Hence modeling provides a more convenient and cost effective means to derive correction factors which are fit for purpose with confidence. In this work we use the Monte Carlo code MCNPX with neutron coincidence tallies to calculate the influence of

  17. Noise-induced hearing loss and symphony orchestra musicians: risk factors, effects, and management.

    Science.gov (United States)

    Teie, P U

    1998-01-01

    Although industrial and recreational noise have been recognized as potential causes of noise-induced hearing loss for quite some time, it is only recently that the sound levels within a symphony orchestra have been implicated as possible sources of harmful noise levels. Many studies have concluded that not only are dangerous levels of noise present within the symphony orchestra, but there is evidence of noise-induced hearing loss among symphony orchestra musicians. Although hearing protection designed for industrial use may not be appropriate for the special listening needs of professional musicians, recent advances in hearing protection design have made hearing protection practical for this population. Suggestions are made for monitoring and protecting the professional ear.

  18. 0069 Psychosocial work factors, occupational noise exposure, common mental disorders, and the risk of tinnitus

    DEFF Research Database (Denmark)

    Winther Frederiksen, Thomas; Ramlau-Hansen, Cecilia H; Stokholm, Zara A

    2014-01-01

    -2010. The study database contained information on individual short-term and long-term noise exposure levels, hearing levels and questionnaire information on common mental disorders and psychosocial work factors. Associations between noise exposure levels, hearing levels, depression, anxiety, burn-out symptoms...... the participants, 17% reported tinnitus, 16% had a hearing handicap (WHO-definition), 3% anxiety disorder, 14% burn-out symptoms, 4% depression, and 8% reported work-related stress. CONCLUSIONS: Tinnitus is expected to represent a heterogeneous group of underlying disorders. We aim at contributing to a better...

  19. Presampling, algorithm factors, and noise: considerations for CT in particular and for medical imaging in general.

    Science.gov (United States)

    Kachelriess, Marc; Kalender, Willi A

    2005-05-01

    CT scanners acquire noisy data at discrete sample positions. Typically, a convention of how to continue these data from discrete integer positions to the continuous domain must be applied during processing. We study the properties of three typical one-dimensional spatial domain interpolation algorithms in terms of a cost or quality factor Q. This figure of merit Q is a function of spatial resolution, data noise, and dose and is used to optimize detector design. Spatial resolution R is defined as either mean square width delta or as the full width at half maximum W of the point spread function (PSF). Our results show that a trapezoidal interpolation algorithm is optimal for the high resolution domain (relative to the detector aperture size g) and should be replaced by a triangular or Gaussian interpolation function for spatial resolutions of about 1.3g or larger; these result in bell-shaped PSFs. Assuming such a hybrid algorithm we find a 1.5-fold increase of Q2-this is equivalent to 50% improved dose usage-when smoothing the data to a spatial resolution of 3g or more compared to a highest resolution reconstruction. Therefore it is advisable to use detectors of one-third of the size of the desired spatial resolution W and to compensate for the 1.5-fold increase in Q2 by reducing dose by 33%. Under the presence of moderately sized septa (e.g., 10% of the spatial resolution element size) the benefit of optimizing still lies in the order of 30% improved dose usage; in that case the detector size g should be on the order of W/2 and a dose reduction of 23% can be achieved. Again, bell-shaped PSFs show a better tradeoff between noise and resolution for a given dose than rectangular-shaped PSFs. The general interpretation of our results is that the degree of freedom of choosing the weighting or interpolation function for a given resolution is large for small detectors and small for large detectors. Thus systems with small g have a higher potential of optimization compared

  20. Basic fibroblast growth factor protects auditory neurons and hair cells from noise exposure and glutamate neurotoxicity

    Institute of Scientific and Technical Information of China (English)

    翟所强; 王大君; 王嘉陵

    2003-01-01

    The purpose of the present study was to determine protectivie effects of basic fibroblast growth factor (bFGF) on cochlear neurons and hair cells in vitro and in vivo. In experiment I, cultured spiral ganglion neurons (SGNs) prepared from P3 mice were exposed to 20mM glutamate for 2 hours before the culture medium was replaced with fresh medium containing 0, 25, 50, and 100 ng/ml bFGF, respectively. Fourteen days later, all cultures were fixed with 4% paraformaldehyde, and stained with 1% toluidine blue. The number of surviving SGNs were counted and the length of SGNs neurites were measured. Exposure to 20 mM glutamate for 24 hours resulted in an inhibition on neurite outgrowth of SGNs and elevated cell death. Treatment of the cultures with bFGF led to promotion of neurite outgrowth and elevated number of surviving SGNs. Effects of bFGF were dose dependent with the highest potency at 100 ng/ml. In experiment Ⅱ, in vivo studies were carried out with guinea pigs in which bFGF or artificial perilymph was perfused into the cochlea to assess possible protective effects of bFGF on cochlear hair cells and compound action potentials(CAP). The CAPs were measured before, immediatly and 48 hours after exposure to noise. Significant differences in CAP were observed (p<0. 05 ) among the bFGF perfused group, control group(t =3. 896 ) and artificial perilymph perfused group (t =2. 520) at 48 hours after noise exposure, Cochleae were removed and hair cell Loss was analyzed in surface preparations prepared from all experimental animals. Acoustic trauma caused loss of 651 and 687 inner hair cells in the control and artificial perilymph perfused group, respectively. In sharp contrast, only 31 inner hair cells were lost in the bFGF perfused ears. Similarly, more outer hair cells died in the control and perilymph perfuesed group (41830 and 41968, respectively) than in the group treated with bFGF (34258). Our results demonstrate that bFGF protected SGNs against glutmate

  1. Derivation of correction factor to be applied for calculated results of PWR fuel isotopic composition by ORIGEN2 code

    Energy Technology Data Exchange (ETDEWEB)

    Suyama, Kenya; Nomura, Yasushi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Murazaki, Minoru [Tokyo Nuclear Service Inc., Tokyo (Japan); Mochizuki, Hiroki [The Japan Research Institute Ltd., Tokyo (Japan)

    2001-11-01

    For providing conservative PWR spent fuel compositions from the view point of nuclear criticality safety, correction factors applicable for result of burnup calculation by ORIGEN2 were evaluated. Its conservativeness was verified by criticality calculations using MVP. To calculate these correction factors, analyses of spent fuel isotopic composition data were performed by ORIGEN2. Maximum or minimum value of the ratio of calculation result to experimental data was chosen as correction factor. These factors are given to each set of fuel assembly and ORIGEN2 library. They could be considered as the re-definition of recommended isotopic composition given in Nuclear Criticality Safety Handbook. (author)

  2. Prevalence and risk factors of noise-induced hearing loss among liquefied petroleum gas (LPG) cylinder infusion workers in Taiwan.

    Science.gov (United States)

    Chang, Shu-Ju; Chang, Chin-Kuo

    2009-12-01

    We assessed the exposure levels of noise, estimated prevalence, and identify risk factors of noise-induced hearing loss (NIHL) among male workers with a cross-sectional study in a liquefied petroleum gas cylinder infusion factory in Taipei City. Male in-field workers exposed to noise and administrative controls were enrolled in 2006 and 2007. Face-to-face interviews were applied for demographics, employment history, and drinking/smoking habit. We then performed the measurements on noise levels in field and administration area, and hearing thresholds on study subjects with standard apparatus and protocols. Existence of hearing loss > 25 dBHL for the average of 500 Hz, 1 kHz, and 2 kHz was accordingly determined for NIHL. The effects from noise exposure, predisposing characteristics, employment-related factors, and personal habits to NIHL were estimated by univariate and multivariate logistic regressions. A total of 75 subjects were involved in research and 56.8% of in-field workers had NIHL. Between the in-field and administration groups, hearing thresholds on the worse ear showed significant differences at frequencies of 4 k, 6 k, and 8 kHz with aging considered. Adjusted odds ratio for field noise exposure (OR=99.57, 95% CI: 3.53, 2,808.74) and frequent tea or coffee consumption (OR=0.03, 95% CI: 0.01, 0.51) were found significant. Current study addressed NIHL in a specific industry in Taiwan. Further efforts in minimizing its impact are still in need.

  3. On the Minimum Safety Factor in Elastic Buckling of Fuel Rod

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Kyu; Kim, Jae Yong; Yoon, Kyung Ho; Lee, Young Ho; Lee, Kang Hee; Kang, Heung Seok; Song, Kun Woo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-10-15

    Elastic buckling of a thin tube is an instantaneous collapse phenomenon due to an external pressure. This should be prohibited for a PWR (Pressurized Water Reactor) fuel rod. There is an engineering formula of it; however, safety factor used to be applied to the calculation results since there will be uncertainty in the parameters of the formulae such as dimensional tolerances, environmental conditions and so forth. It is a designer's responsibility to determine an appropriate safety factor that is acceptably economically conservative. Mechanical properties of a material are usually adopted from a material handbook. However, they are usually different from the measured values of the material actually used. A local dimension anomaly critically affects the elastic buckling. Conventional safety factors against the elastic buckling seemed to be large (more than 3.5). However, the reason for this is rarely found. Engineering experience may be incorporated. Therefore, it is highly necessary to propose a minimum safety factor on the elastic buckling while accommodating the above mentioned uncertainties. It is so especially for the dual cooled fuel rod since it has never been used before. The primary purpose of this work is to quantify the aforementioned uncertainties of the parameters in the elastic buckling formula, especially for an outer cladding of the currently studied dual cooled fuel rod. It is extended from the previous theoretical and experimental study

  4. Self-reported noise exposure as a risk factor for long-term sickness absence

    DEFF Research Database (Denmark)

    Clausen, Thomas; Christensen, Karl Bang; Lund, Thomas;

    2009-01-01

    -quarter and three-quarters of their time at work had an increased risk of 43% (CI: 10-85%) for sickness absence of two weeks or longer compared to men that reported never to be exposed to loud noise. Men that reported to be little/rarely exposed to loud noise had an increased risk of 37% (CI: 7-76%). Men...... that reported to be exposed to loud noise more than three-quarters of their time at work did not have an increased risk of sickness absence. This latter result might be due a healthy worker effect and/or more frequent use of hearing protection in this group. Along with evidence from previous studies......Self-reported noise exposure is on the rise in Denmark. Little is known, however, about the social consequences, including sickness absence, of noise exposure. The aim of this paper was to investigate the association between self-reported noise exposure and long-term sickness absence...

  5. State-of-the-Art Review on Sustainable Design and Construction of Quieter Pavements—Part 2: Factors Affecting Tire-Pavement Noise and Prediction Models

    Directory of Open Access Journals (Sweden)

    Okan Sirin

    2016-07-01

    Full Text Available Traffic noise is a combination of noises produced from a number of sources. Of all the traffic noise sources, tire-pavement noise, which is emitted as a result of the interaction of rolling, slipping, or dragging tires and the pavement surface, is the dominant contributor of overall noise, particularly when vehicles are moving at higher speeds. Therefore, a number of research studies have been conducted to identify and analyze the factors affecting the generation of tire-pavement interaction noise. This helps in identifying and selecting appropriate noise mitigation techniques. In this paper, an extensive literature survey on the factors affecting tire-pavement noise is presented, and different views on the impact of each individual factor are discussed. From the literature survey, it is also evident that there is a potential correlation between pavement’s material characteristics and tire-pavement noise. A comprehensive discussion about this correlation is presented in the paper. In addition, this paper discusses various mathematical models for predicting pavement noise, and their advantages and shortcomings.

  6. Test Research on Exhaust Noise for Gasoline Engine Combusting Methanol-Gasoline Flexible Fuel%汽油机燃用甲醇-汽油灵活燃料的排气噪声试验研究

    Institute of Scientific and Technical Information of China (English)

    黄华; 崔国旭; 施兵峰; 陈振斌

    2016-01-01

    Under the condition that electronic control gasoline engine parameters aren't made any adjustment, and calibration based on pure gasoline fuel control strategy, the test combusting methanol-gasoline flexible fuel is carried out. It researches the influence on the exhaust noise characteristics by combusting flexible fuel (M15 and M85) through an engine. The test result under wide throttle open shows that in middle and high speed, exhaust noise of using methanol-gasoline fuel is higher than gasoline (M0), and the higher the methanol proportion, the heavier the exhaust noise is. At low speed, the condition is opposite. Through the curve of cylinder pressure and exhaust speed, it illustrates the reason of noise change. At last it researches noise change through simulating car driving on road at test bench, and the result shows that the noise decreases overall.%在电控汽油机参数未作任何调整的情况下,采用基于纯汽油标定的燃油控制策略,研究了某款车用汽油机燃用甲醇-汽油灵活燃料(M15和M85)对排气噪声特性的影响.结果表明:节气门全开时燃用甲醇-汽油混合燃料,在中、高转速时,排气噪声高于纯汽油(M0),且甲醇比例越高,排气噪声越大;在低转速时,则相反.同时,通过缸压曲线和排气流速,分析了噪声变化的原因.最后在台架上模拟整车在道路上运行时的噪声变化情况,总体上噪声下降.

  7. Noise suppression by noise

    OpenAIRE

    Vilar, J. M. G.; Rubí Capaceti, José Miguel

    2001-01-01

    We have analyzed the interplay between an externally added noise and the intrinsic noise of systems that relax fast towards a stationary state, and found that increasing the intensity of the external noise can reduce the total noise of the system. We have established a general criterion for the appearance of this phenomenon and discussed two examples in detail.

  8. Occupational Exposure to Mineral Turpentine and Heavy Fuels: A Possible Risk Factor for Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    Rafik Helou

    2014-06-01

    Full Text Available Background: The association between solvents and Alzheimer's disease (AD has been the subject of several studies. Yet, only few studies have examined the various solvents separately, and the controls have rarely been monitored long enough. For these reasons and others, we believe that further studies are required. Objectives: The objective of this study was to identify solvents associated with the clinicoradiological diagnostic of AD or mixed-type dementia (MD. Methods: A retrospective case-control study was performed in 156 patients followed up at the Memory Diagnostic Center of Bertinot Juel Hospital (France. The inclusion criteria were known occupation(s, a Mini-Mental State Examination (MMSE score ≥10 at the first visit, a neuropsychological evaluation performed and a diagnosis established in our Memory Diagnostic Center. The diagnostics were crossed with 9 solvents belonging to two classes of solvents. Exposure was evaluated using French national job-exposure matrices. Results: Certain petroleum-based solvents and fuels (i.e. mineral turpentine, diesel fuel, fuel oil and kerosene were associated with a diagnosis of AD or MD. This association was still significant after adjustment for age, sex and education (adjusted OR: 6.5; 95% CI: 2-20. Conclusion: Occupational exposure to mineral turpentine and heavy fuels may be a risk factor for AD and MD.

  9. Use of impedance spectroscopy to investigate factors that influence the performance and durability of proton exchange membrane (PEM) fuel cells

    Science.gov (United States)

    Roy, Sunil K.

    an insight into the problem of flooding which adversely affects the performance of the fuel cell was established. A comprehensive model for base-level noise in impedance measurements for normal (non-flooded) conditions was developed and actual noise in flooded conditions was calculated by transient fixed-frequency measurements. A comparison of the actual noise to the base-level noise was used to detect onset of flooding. Also, graphical methods were used to interpret impedance spectra in terms of interfacial capacitance. The effective interfacial capacitance decreased with increase in current and decreased slowly with time. The decreases in interfacial capacitance with higher current density can be attributed to an excess amount of water i.e., flooding; whereas, the decrease in interfacial capacitance with time may be related to catalyst dissolution and deactivation.

  10. Particulate emission factors for mobile fossil fuel and biomass combustion sources.

    Science.gov (United States)

    Watson, John G; Chow, Judith C; Chen, L-W Antony; Lowenthal, Douglas H; Fujita, Eric M; Kuhns, Hampden D; Sodeman, David A; Campbell, David E; Moosmüller, Hans; Zhu, Dongzi; Motallebi, Nehzat

    2011-05-15

    PM emission factors (EFs) for gasoline- and diesel-fueled vehicles and biomass combustion were measured in several recent studies. In the Gas/Diesel Split Study (GD-Split), PM(2.5) EFs for heavy-duty diesel vehicles (HDDV) ranged from 0.2 to ~2 g/mile and increased with vehicle age. EFs for HDDV estimated with the U.S. EPA MOBILE 6.2 and California Air Resources Board (ARB) EMFAC2007 models correlated well with measured values. PM(2.5) EFs measured for gasoline vehicles were ~two orders of magnitude lower than those for HDDV and did not correlate with model estimates. In the Kansas City Study, PM(2.5) EFs for gasoline-powered vehicles (e.g., passenger cars and light trucks) were generally fuel, corresponding to 0.3 and 2 g/mile, respectively. These values are comparable to those of on-road HDDV. EFs for biomass burning measured during the Fire Laboratory at Missoula Experiment (FLAME) were compared with EFs from the ARB Emission Estimation System (EES) model. The highest PM(2.5) EFs (76.8±37.5 g/kg) were measured for wet (>50% moisture content) Ponderosa Pine needles. EFs were generally fuels with low moisture content but underestimated measured EFs for fuel with moisture content >40%. Average EFs for dry chamise, rice straw, and dry grass were within a factor of three of values adopted by ARB in California's San Joaquin Valley (SJV). Discrepancies between measured and modeled emission factors suggest that there may be important uncertainties in current PM(2.5) emission inventories.

  11. STUDY ON THE RELATIONSHIP BETWEEN ADJUSTABLE OPERATIONAL PARAMETERS AND NOISE OF SINGLE-CYLINDER DIESEL ENGINE

    Institute of Scientific and Technical Information of China (English)

    何勇; 鲍一丹

    2001-01-01

    A Model S195 (8.8 kW) single cylinder was used in this study to determine the effect of four operational parameters, i.e. intake valve close angle, exhaust valve open angle, fuel delivery angle and fuel injection pressure on noise. Single factor and multi-factor quadratic regressive orthogonal methods were adopted in the experiments to find the relationship between the four parameters and noise. By means of optimization technique, the optimum operational parameters for two working conditions of the engine were selected and the test results showed that optimum adjustment could reduce noise by 2-4 dB.

  12. Environmental data book 2011. Estimated emission factors for fuels, electricity, heat and transport in Sweden; Miljoefaktaboken 2011. Uppskattade emissionsfaktorer foer braenslen, el, vaerme och transporter

    Energy Technology Data Exchange (ETDEWEB)

    Gode, Jenny; Martinsson, Fredrik; Hagberg, Linus; Oeman, Andreas; Hoeglund, Jonas; Palm, David

    2011-04-15

    The environmental data book summarizes current and general emission factors for most fuels and sources of Swedish electricity and heat and to power vehicles. Emission data are compiled for wood fuels, energy crops, bio-oils, waste fuels, fossil fuels and peat, biofuels, wind power, hydro power, nuclear power and solar power

  13. The effects of aquaculture production noise on the growth, condition factor, feed conversion, and survival of rainbow trout, Oncorhynchus mykiss

    Science.gov (United States)

    Davidson, J.; Bebak, J.; Mazik, P.

    2009-01-01

    Intensive aquaculture systems, particularly recirculating systems, utilize equipment such as aerators, air and water pumps, blowers, and filtration systems that inadvertently increase noise levels in fish culture tanks. Sound levels and frequencies measured within intensive aquaculture systems are within the range of fish hearing, but species-specific effects of aquaculture production noise are not well defined. Field and laboratory studies have shown that fish behavior and physiology can be negatively impacted by intense sound. Therefore, chronic exposure to aquaculture production noise could cause increased stress, reduced growth rates and feed conversion efficiency, and decreased survival. The objective of this study was to provide an in-depth evaluation of the long term effects of aquaculture production noise on the growth, condition factor, feed conversion efficiency, and survival of cultured rainbow trout, Oncorhynchus mykiss. Rainbow trout were cultured in replicated tanks using two sound treatments: 117??dB re 1????Pa RMS which represented sound levels lower than those recorded in an intensive recycle system and 149??dB re 1????Pa RMS, representing sound levels near the upper limits known to occur in recycle systems. To begin the study mean fish weights in the 117 and 149??dB tanks were 40 and 39??g, respectively. After five months of exposure no significant differences were identified between treatments for mean weight, length, specific growth rates, condition factor, feed conversion, or survival (n = 4). Mean final weights for the 117 and 149??dB treatments were 641 ?? 3 and 631 ?? 10??g, respectively. Overall specific growth rates were equal, i.e. 1.84 ?? 0.00 and 1.84 ?? 0.01%/day. Analysis of growth rates of individually tagged rainbow trout indicated that fish from the 149??dB tanks grew slower during the first month of noise exposure (p noise thereafter. This study further suggests that rainbow trout growth and survival are unlikely to be affected

  14. Photobiomodulation rescues the cochlea from noise-induced hearing loss via upregulating nuclear factor κB expression in rats.

    Science.gov (United States)

    Tamura, Atsushi; Matsunobu, Takeshi; Tamura, Risa; Kawauchi, Satoko; Sato, Shunichi; Shiotani, Akihiro

    2016-09-01

    Photobiomodulation (PBM) is a noninvasive treatment that can be neuroprotective, although the underlying mechanisms remain unclear. In the present study, we assessed the mechanism of PBM as a novel treatment for noise-induced hearing loss, focusing on the nuclear factor (NF)-κB signaling pathway. Sprague-Dawley rats were exposed to 1-octave band noise centered at 4kHz for 5h (121dB). After noise exposure, their right ears were irradiated with an 808nm diode laser beam at an output power density of 165mW/cm(2) for 30min a day for 5 consecutive days. Measurement of the auditory brainstem response revealed an accelerated recovery of auditory function in the groups treated with PBM compared with the non-treatment group at 4, 7, and 14 days after noise exposure. Immunofluorescent image analysis for inducible nitric oxide synthase and cleaved caspase-3 showed lesser immunoreactivities in outer hair cells in the PBM group compared with the non-treatment group. However, immunofluorescent image analysis for NF-κB, an upstream protein of inducible nitric oxide synthase, revealed greater activation in the PBM group compared with the naïve and non-treatment groups. Western blot analysis for NF-κB also showed stronger activation in the cochlear tissues in the PBM group compared with the naïve and non-treatment groups (p<0.01, each). These data suggest that PBM activates NF-κB to induce protection against inducible nitric oxide synthase-triggered oxidative stress and caspase-3-mediated apoptosis that occur following noise-induced hearing loss.

  15. Speech Enhancement Algorithm Using Sub band Two Step Decision Directed Approach with Adaptive Weighting factor and Noise Masking Threshold

    Directory of Open Access Journals (Sweden)

    Deepa Dhanaskodi

    2011-01-01

    Full Text Available Problem statement: Speech Enhancement plays an important role in any of the speech processing systems like speech recognition, mobile communication, hearing aid. Approach: In this work, human perceptual auditory masking effect is incorporated into the single channel speech enhancement algorithm. The algorithm is based on a criterion by which the audible noise may be masked rather than being attenuated and thereby reducing the chance of distortion to speech. The basic decision directed approach is for efficient reduction of musical noise, that includes the estimation of the a priori SNR which is a crucial parameter of the spectral gain, follows the a posteriori SNR with a delay of one frame in speech frames. In this work a simple adaptive speech enhancement technique, using an adaptive sigmoid type function to determine the weighting factor of the TSDD algorithm is employed based on a sub band approach. In turn the spectral estimate is used to obtain a perceptual gain factor. Results: Objective and subjective measures like SNR, MSE, IS distance and were obtained, which shows the ability of the proposed method for efficient enhancement of noisy speech Conclusion/Recommendations: Performance assessment shows that our proposal can achieve a more significant noise reduction and a better spectral estimation of weak speech spectral components from a noisy signal as compared to the conventional speech enhancement algorithm.

  16. Main Influencing Factors of Automobile Fuel Consumption Testing with Ultrasonic Technology%汽车超声波油耗测试主要影响因素

    Institute of Scientific and Technical Information of China (English)

    付百学; 胡胜海

    2014-01-01

    Combining with the development level and development trend of automotive fuel consumption test technology, and adopting the ultrasonic technology and single-chip microcomputer control technology, a research was made on the automotive fuel consumption test technology. The mathematical calculation model of automobile fuel consumption test was established based on the fuel consumption test theory of ultrasonic time difference method. The fuel flow rate was modified by means of flow correction coefficient based on fluid mechanics theory. Analyzing the geometry parameters’ influence of the ultrasonic flow sensor on automobile fuel consumption test, and using the 3 d coordinate method, the ultrasonic flow sensor’s geometry parameters can be accurately calculated. By analyzing the environmental temperature’s influence on the flow rate correction coefficient and the propagation velocity of ultrasonic wave in the fuel, modification measures were put forward. Quantitatively analyzing the parameters of sound and threshold value which influence calculating ultrasonic transmission time, eliminating the frequency noise using the maximum likelihood estimation method, and reasonably choosing the threshold value, the simulation results showed that automobile fuel consumption testing accuracy was up to 12 ns. Comprehensively taking into account the influencing factors of fuel consumption test and taking corrective measures can optimize the mathematical calculation model of automobile fuel consumption test, and improve the automobile fuel consumption test accuracy. Thus, it will lay a theoretical foundation for the research and development of an ultrasonic automobile fuel consumption testing instrument.%结合汽车油耗测试技术的研发水平及发展趋势,采用超声波技术和单片机控制技术,进行汽车油耗测试技术研究。基于超声波时差法油耗测试理论,构建汽车油耗测试的数学计算模型。基于流体力学理论,采用

  17. 78 FR 17660 - Draft Guidance for E85 Flexible Fuel Vehicle Weighting Factor for Model Years 2016-2019 Vehicles...

    Science.gov (United States)

    2013-03-22

    ... AGENCY Draft Guidance for E85 Flexible Fuel Vehicle Weighting Factor for Model Years 2016-2019 Vehicles... determined by weighting the gasoline and E85 values of the model together using the specified factor (see 40... that EPA provide a weighting factor to use for 2016 and later model year vehicles. EPA has assessed the...

  18. Experimental factors that influence carbon monoxide tolerance of high-temperature proton-exchange membrane fuel cells

    Science.gov (United States)

    Kwon, Kyungjung; Yoo, Duck Young; Park, Jung Ock

    The poisoning effect of carbon monoxide (CO) on high-temperature proton-exchange membrane fuel cells (PEMFCs) is investigated with respect to CO concentration, operating temperature, fuel feed mode, and anode Pt loading. The loss in cell voltage when CO is added to pure hydrogen anode gas is a function of fuel utilization and anode Pt loading as well as obvious factors such as CO concentration, temperature and current density. The tolerance to CO can be varied significantly using a different experimental design of fuel utilization and anode Pt loading. A difference in cell performance with CO-containing hydrogen is observed when two cells with different flow channel geometries are used, although the two cells show similar cell performance with pure hydrogen. A different combination of fuel utilization, anode Pt loading and flow channel design can cause an order of magnitude difference in CO tolerance under identical experimental conditions of temperature and current density.

  19. Experimental factors that influence carbon monoxide tolerance of high-temperature proton-exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Kyungjung; Yoo, Duck Young; Park, Jung Ock [Energy and Environment Lab, Samsung Advanced Institute of Technology, Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-712 (Korea)

    2008-10-15

    The poisoning effect of carbon monoxide (CO) on high-temperature proton-exchange membrane fuel cells (PEMFCs) is investigated with respect to CO concentration, operating temperature, fuel feed mode, and anode Pt loading. The loss in cell voltage when CO is added to pure hydrogen anode gas is a function of fuel utilization and anode Pt loading as well as obvious factors such as CO concentration, temperature and current density. The tolerance to CO can be varied significantly using a different experimental design of fuel utilization and anode Pt loading. A difference in cell performance with CO-containing hydrogen is observed when two cells with different flow channel geometries are used, although the two cells show similar cell performance with pure hydrogen. A different combination of fuel utilization, anode Pt loading and flow channel design can cause an order of magnitude difference in CO tolerance under identical experimental conditions of temperature and current density. (author)

  20. Factors limiting performance in a multitone intensity-discrimination task: disentangling non-optimal decision weights and increased internal noise.

    Directory of Open Access Journals (Sweden)

    Daniel Oberfeld

    Full Text Available To identify factors limiting performance in multitone intensity discrimination, we presented sequences of five pure tones alternating in level between loud (85 dB SPL and soft (30, 55, or 80 dB SPL. In the "overall-intensity task", listeners detected a level increment on all of the five tones. In the "masking task", the level increment was imposed only on the soft tones, rendering the soft tones targets and loud tones task-irrelevant maskers. Decision weights quantifying the importance of the five tone levels for the decision were estimated using methods of molecular psychophysics. Compatible with previous studies, listeners placed higher weights on the loud tones than on the soft tones in the overall-intensity condition. In the masking task, the decisions were systematically influenced by the to-be-ignored loud tones (maskers. Using a maximum-likelihood technique, we estimated the internal noise variance and tested whether the internal noise was higher in the alternating-level five-tone sequences than in sequences presenting only the soft or only the loud tones. For the overall-intensity task, we found no evidence for increased internal noise, but listeners applied suboptimal decision weights. These results are compatible with the hypothesis that the presence of the loud tones does not impair the precision of the representation of the intensity of the soft tones available at the decision stage, but that this information is not used in an optimal fashion due to a difficulty in attending to the soft tones. For the masking task, in some cases our data indicated an increase in internal noise. Additionally, listeners applied suboptimal decision weights. The maximum-likelihood analyses we developed should also be useful for other tasks or other sensory modalities.

  1. A proposed model of factors influencing hydrogen fuel cell vehicle acceptance

    Science.gov (United States)

    Imanina, N. H. Noor; Kwe Lu, Tan; Fadhilah, A. R.

    2016-03-01

    Issues such as environmental problem and energy insecurity keep worsening as a result of energy use from household to huge industries including automotive industry. Recently, a new type of zero emission vehicle, hydrogen fuel cell vehicle (HFCV) has received attention. Although there are argues on the feasibility of hydrogen as the future fuel, there is another important issue, which is the acceptance of HFCV. The study of technology acceptance in the early stage is a vital key for a successful introduction and penetration of a technology. This paper proposes a model of factors influencing green vehicle acceptance, specifically HFCV. This model is built base on two technology acceptance theories and other empirical studies of vehicle acceptance. It aims to provide a base for finding the key factors influencing new sustainable energy fuelled vehicle, HFCV acceptance which is achieved by explaining intention to accept HFCV. Intention is influenced by attitude, subjective norm and perceived behavioural control from Theory of Planned Behaviour and personal norm from Norm Activation Theory. In the framework, attitude is influenced by perceptions of benefits and risks, and social trust. Perceived behavioural control is influenced by government interventions. Personal norm is influenced by outcome efficacy and problem awareness.

  2. The influence of acoustical and non-acoustical factors on short-term annoyance due to aircraft noise in the field - The COSMA study.

    Science.gov (United States)

    Bartels, Susanne; Márki, Ferenc; Müller, Uwe

    2015-12-15

    Air traffic has increased for the past decades and is forecasted to continue to grow. Noise due to current airport operations can impair the physical and psychological well-being of airport residents. The field study investigated aircraft noise-induced short-term (i.e., within hourly intervals) annoyance in local residents near a busy airport. We aimed at examining the contribution of acoustical and non-acoustical factors to the annoyance rating. Across four days from getting up till going to bed, 55 residents near Cologne/Bonn Airport (M=46years, SD=14years, 34 female) rated their annoyance due to aircraft noise at hourly intervals. For each participant and each hour, 26 noise metrics from outdoor measurements and further 6 individualized metrics that took into account the sound attenuation due to each person's whereabouts in and around their homes were obtained. Non-acoustical variables were differentiated into situational factors (time of day, performed activity during past hour, day of the week) and personal factors (e.g., sensitivity to noise, attitudes, domestic noise insulation). Generalized Estimation Equations were applied for the development of a prediction model for annoyance. Acoustical factors explained only a small proportion (13.7%) of the variance in the annoyance ratings. The number of fly-overs predicted annoyance better than did equivalent and maximum sound pressure levels. The proportion of explained variance in annoyance rose considerably (to 27.6%) when individualized noise metrics as well as situational and personal variables were included in the prediction model. Consideration of noise metrics related to the number of fly-overs and individual adjustment of noise metrics can improve the prediction of short-term annoyance compared to models using equivalent outdoor levels only. Non-acoustical factors have remarkable impact not only on long-term annoyance as shown before but also on short-term annoyance judged in the home environment. Copyright

  3. Exposures to road traffic, noise, and air pollution as risk factors for type 2 diabetes: A feasibility study in Bulgaria

    Directory of Open Access Journals (Sweden)

    Angel M Dzhambov

    2016-01-01

    Full Text Available Type 2 diabetes mellitus (T2DM is a growing public health problem in Bulgaria. While individual and lifestyle determinants have been researched; till date there has been no study on environmental risks such as road traffic, noise, and air pollution. As a first step toward designing a large-scale population-based survey, we aimed at exploring the overall associations of prevalent T2DM with exposures to road traffic, noise, and air pollution. A total of 513 residents of Plovdiv city, Bulgaria were recruited. Individual data on self-reported doctor-diagnosed T2DM and confounding factors were linked to objective and self-rated exposure indicators. Logistic and log-link Poisson regressions were conducted. In the fully adjusted logistic models, T2DM was positively associated with exposures to L den 71-80 dB (odds ratio (OR = 4.49, 95% confidence interval (CI: 1.38, 14.68, fine particulate matter (PM 2.5 25.0-66.8 μg/m 3 (OR = 1.32, 95% CI: 0.28, 6.24, benzo alpha pyrene 6.0-14.02 ng/m 3 (OR = 1.76, 95% CI: 0.52, 5.98 and high road traffic (OR = 1.40, 95% CI: 0.48, 4.07. L den remained a significant risk factor in the: Poisson regression model. Other covariates with consistently high multivariate effects were age, gender, body mass index, family history of T2DM, subjective sleep disturbance, and especially bedroom location. We concluded that residential noise exposure might be associated with elevated risk of prevalent T2DM. The inferences made by this research and the lessons learned from its limitations could guide the designing of a longitudinal epidemiological survey in Bulgaria.

  4. Exposures to road traffic, noise, and air pollution as risk factors for type 2 diabetes: A feasibility study in Bulgaria.

    Science.gov (United States)

    Dzhambov, Angel M; Dimitrova, Donka D

    2016-01-01

    Type 2 diabetes mellitus (T2DM) is a growing public health problem in Bulgaria. While individual and lifestyle determinants have been researched; till date there has been no study on environmental risks such as road traffic, noise, and air pollution. As a first step toward designing a large-scale population-based survey, we aimed at exploring the overall associations of prevalent T2DM with exposures to road traffic, noise, and air pollution. A total of 513 residents of Plovdiv city, Bulgaria were recruited. Individual data on self-reported doctor-diagnosed T2DM and confounding factors were linked to objective and self-rated exposure indicators. Logistic and log-link Poisson regressions were conducted. In the fully adjusted logistic models, T2DM was positively associated with exposures to L(den) 71-80 dB (odds ratio (OR) = 4.49, 95% confidence interval (CI): 1.38, 14.68), fine particulate matter (PM) 2.5 25.0-66.8 μg/m 3 (OR = 1.32, 95% CI: 0.28, 6.24), benzo alpha pyrene 6.0-14.02 ng/m 3 (OR = 1.76, 95% CI: 0.52, 5.98) and high road traffic (OR = 1.40, 95% CI: 0.48, 4.07). L(den) remained a significant risk factor in the: Poisson regression model. Other covariates with consistently high multivariate effects were age, gender, body mass index, family history of T2DM, subjective sleep disturbance, and especially bedroom location. We concluded that residential noise exposure might be associated with elevated risk of prevalent T2DM. The inferences made by this research and the lessons learned from its limitations could guide the designing of a longitudinal epidemiological survey in Bulgaria.

  5. Emission factors of air pollutants from CNG-gasoline bi-fuel vehicles: Part I. Black carbon.

    Science.gov (United States)

    Wang, Yang; Xing, Zhenyu; Xu, Hui; Du, Ke

    2016-12-01

    Compressed natural gas (CNG) is considered to be a "cleaner" fuel compared to other fossil fuels. Therefore, it is used as an alternative fuel in motor vehicles to reduce emissions of air pollutants in transportation. To quantify "how clean" burning CNG is compared to burning gasoline, quantification of pollutant emissions under the same driving conditions for motor vehicles with different fuels is needed. In this study, a fleet of bi-fuel vehicles was selected to measure the emissions of black carbon (BC), carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) for driving in CNG mode and gasoline mode respectively under the same set of constant speeds and accelerations. Comparison of emission factors (EFs) for the vehicles burning CNG and gasoline are discussed. This part of the paper series reports BC EFs for bi-fuel vehicles driving on the real road, which were measured using an in situ method. Our results show that burning CNG will lead to 54%-83% reduction in BC emissions per kilometer, depending on actual driving conditions. These comparisons show that CNG is a cleaner fuel than gasoline for motor vehicles in terms of BC emissions and provide a viable option for reducing BC emissions cause by transportation. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Soil factors of ecosystems' disturbance risk reduction under the impact of rocket fuel

    Science.gov (United States)

    Krechetov, Pavel; Koroleva, Tatyana; Sharapova, Anna; Chernitsova, Olga

    2016-04-01

    Environmental impacts occur at all stages of space rocket launch. One of the most dangerous consequences of a missile launch is pollution by components of rocket fuels ((unsymmetrical dimethylhydrazine (UDMH)). The areas subjected to falls of the used stages of carrier rockets launched from the Baikonur cosmodrome occupy thousands of square kilometers of different natural landscapes: from dry steppes of Kazakhstan to the taiga of West Siberia and mountains of the Altai-Sayany region. The study aims at assessing the environmental risk of adverse effects of rocket fuel on the soil. Experimental studies have been performed on soil and rock samples with specified parameters of the material composition. The effect of organic matter, acid-base properties, particle size distribution, and mineralogy on the decrease in the concentration of UDMH in equilibrium solutions has been studied. It has been found that the soil factors are arranged in the following series according to the effect on UDMH mobility: acid-base properties > organic matter content >clay fraction mineralogy > particle size distribution. The estimation of the rate of self-purification of contaminated soil is carried out. Experimental study of the behavior of UDMH in soil allowed to define a model for calculating critical loads of UDMH in terrestrial ecosystems.

  7. The combustion of fuel oil and the factors influencing pollutant formation

    Energy Technology Data Exchange (ETDEWEB)

    Sedighi, Kurosh.

    1990-03-01

    This study presents in-flame and flue gas emission data with particular emphasis on the emission of NO{sub x} compounds arising from oil spray combustion. Experimental studies were carried out in a cylindrical ceramic-lined tunnel furnace using a pressure jet swirl oil burner. This burner was characterized in terms of the droplet size and spray pattern it produced in order to investigate the effect of these parameters on system performance with regard to NO formation. Six operating conditions were used and the NO and NO{sub x} emissions in the flame and post flame regions were reported. The majority of NO in the system was formed via the oxidation of nitrogenous species produced close to the burner. The effect of mean droplet size on the NO formation was investigated and the results showed that any factor which tended to produce smaller fuel droplets promoted an increase in the NO emission. In-flame radial and axial profiles were used to elucidate the mechanism of NO formation with regard to burner operation conditions. The burning rate of the fuel droplets was also modelled theoretically for the experimental conditions investigated. Predictions of NO formation chemistry were undertaken using a kinetic package. A post-processing NO model using the FLUENT computer code was also used. (Author).

  8. Test of the Influence of Using Mixed Methanol-gasoline Fuel on Engine Exhaust Noise%甲醇汽油对发动机排气噪声影响的试验

    Institute of Scientific and Technical Information of China (English)

    殷俊; 张冰蔚

    2015-01-01

    With an improved 1.5 VCT engine as the test platform, the influence of combusting methanol-gasoline flexible fuel on the engine exhaust noise was investigated. The result of full speed load character test shows that the exhaust noise of the engine at middle and high speed for using methanol-gasoline fuel is higher than that for using gasoline. The difference of the engine exhaust noise between them can reach the maximum value of 4.0 dB (A) at 6 000 r/min speed. The result of load character test at 4 500 r/min speed shows that the exhaust noise for using methanol-gasoline fuel will increase when the load reaches 32%of the maximum load of M0.%以一款经过改造后的1.5 VCT发动机为试验研究平台,研究燃用甲醇汽油灵活燃料对排气噪声特性的影响.外特性试验结果表明甲醇汽油在中、高转速时使排气噪声增大,其中6 000 r/min时最大增加4.0 dB(A);负荷特性(4 500 r/min)试验表明负荷达到M0最大负荷的32%以上时排气噪声也会增大.

  9. Estimation of retention factor of cesium in sodium pool under fuel pin failure scenario in SFR

    Energy Technology Data Exchange (ETDEWEB)

    Pradeep, Arjun [Computational Simulation Section, Safety Engineering Division, Nuclear and Safety Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Rao, P. Mangarjuna, E-mail: pmr@igcar.gov.in [Computational Simulation Section, Safety Engineering Division, Nuclear and Safety Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Nashine, B.K.; Chellapandi, P. [Computational Simulation Section, Safety Engineering Division, Nuclear and Safety Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer We model retention factor of cesium in infinite dilute solution of sodium pool. Black-Right-Pointing-Pointer We study variation in retention factor with cover gas temperature gradient. Black-Right-Pointing-Pointer Increasing height and temperature difference decreases the retention factor. Black-Right-Pointing-Pointer In infinite dilution regime retention factor is independent of cesium inventory. Black-Right-Pointing-Pointer The retention factor is useful in estimating source term in cover gas region. - Abstract: Radioactive source term in argon (Ar) cover gas region of the primary vessel due to cesium (Cs) leaked from the failed fuel pins into the primary coolant of Sodium cooled Fast Reactor (SFR) depends on its thermodynamic and kinetic behavior with the coolant sodium. Evaluation of this source term requires detailed knowledge on the distribution of Cs between large volume of the liquid sodium, and the inert Ar cover gas. Solute-solvent combination like liquid Cs and sodium, with relative volatility greater than unity, is an important system to be analyzed in the context of SFR safety. Distribution of Cs between Ar cover gas and liquid sodium pool is complicated by the imposition of temperature difference across the cover gas region and its resultant enrichment of the more volatile solute. An analytical model has been developed to obtain the geometry dependent Retention Factor (RF) of Cs in the sodium pool as a function of the height of cover gas, initial mass inventory of Cs, the temperature difference across the cover gas region (between the sodium pool surface and top roof bottom plate) for an infinite dilute solution of Cs in the sodium pool. The model predicted results are validated with available experimental results in the literature and found that they are fairly in good agreement. In the infinite dilute solution (IDS) regime sodium pool is having the retention capacity to keep the Cs from being released into

  10. PWR-UO{sub 2} nuclear fuel criticality study: control rod effects on infinite neutron multiplication factor and spent fuel composition

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, R.V.; Pereira, C., E-mail: claubia@nuclear.ufmg.br; Silva, C.A.M.; Costa, A.L.; Veloso, M.A.F.; Oliveira, A.H. de

    2013-10-15

    Highlights: • A three-dimensional model of a PWR fuel were simulated. • Results using TRITON/T6-DEPL module in SCALE 6.0 and two libraries (238 and 44 groups) were compared. • Variations in the infinite neutron multiplication factor and the nuclides concentrations, both under control rod insertion effects were analysed. • Results show very good agreement with those published by OECD. -- Abstract: Deterministic and stochastic nuclear codes are software packages used to perform reactor physics calculations, especially in PWRs, the most common type of nuclear reactor currently in operation. The NEA Expert Group on Burn-up Credit Criticality Safety has published a Benchmark with results obtained from simulations of PWR-UO{sub 2} nuclear fuel. The same simulations were performed at DEN/UFMG with SCALE 6.0, a modular nuclear system code developed by Oak Ridge National Laboratory using two different neutron energy libraries (238 and 44 groups). The results obtained using a three-dimensional model with the T6-DEPL sequence of the TRITON module in SCALE 6.0 for spent fuel inventory and infinite neutron multiplication factor calculations show very good agreement with those published by the OECD. The main goal of this work is to validate the methodology at DEN/UFMG for future use in simulations related to Angra I, II and III Nuclear Power Plants.

  11. On non-negative matrix factorization algorithms for signal-dependent noise with application to electromyography data

    Science.gov (United States)

    Devarajan, Karthik; Cheung, Vincent C.K.

    2017-01-01

    Non-negative matrix factorization (NMF) by the multiplicative updates algorithm is a powerful machine learning method for decomposing a high-dimensional nonnegative matrix V into two nonnegative matrices, W and H where V ~ WH. It has been successfully applied in the analysis and interpretation of large-scale data arising in neuroscience, computational biology and natural language processing, among other areas. A distinctive feature of NMF is its nonnegativity constraints that allow only additive linear combinations of the data, thus enabling it to learn parts that have distinct physical representations in reality. In this paper, we describe an information-theoretic approach to NMF for signal-dependent noise based on the generalized inverse Gaussian model. Specifically, we propose three novel algorithms in this setting, each based on multiplicative updates and prove monotonicity of updates using the EM algorithm. In addition, we develop algorithm-specific measures to evaluate their goodness-of-fit on data. Our methods are demonstrated using experimental data from electromyography studies as well as simulated data in the extraction of muscle synergies, and compared with existing algorithms for signal-dependent noise. PMID:24684448

  12. Multi-noise factors flight tracks clustering for airport noise prediction%面向机场噪声预测的多噪声因素航迹聚类

    Institute of Scientific and Technical Information of China (English)

    吕宗平; 李永祥; 徐涛

    2015-01-01

    The existing noise prediction model mainly adopts machine learning methods to predict single noise monitoring point value,which is unable to estimate and forecast the scope and area of the noise in its totality.A flight tracks similarity measure method based on the measure of area between in the flight tracks was presented,combined with tracks data,aircraft speeds and aircraft engine thrust,multi-noise factors flight tracks clustering model for airport noise prediction was built.The flight tracks clustering results were put into INM (integrated noise model).The experimental results show that the noise influence area and noise value made by the flight tracks within the same cluster are very similar,and the proposed model can measure the flight tracks similarity more profitably and the results of flight tracks clustering are better.%现有的噪声预测模型主要采用机器学习的方法预测单一噪声监测点,无法从全局上对噪声的影响范围和大小进行整体评估和预测。为此,提出一种基于航迹间面积的航迹相似性度量方法,结合航迹数据、飞行速度、飞机发动机推力等因素,构建适合机场噪声预测的多噪声影响因素航迹聚类模型。将使用该模型获得的聚类结果导入机场噪声预测模型软件INM (integrated noise model),实验分析结果表明,簇内航迹对机场周围的噪声影响范围和大小相似,能够更好地度量航迹之间的相似性,航迹聚类效果更好。

  13. Minimum-noise production of translation factor eIF4G maps to a mechanistically determined optimal rate control window for protein synthesis

    Science.gov (United States)

    Meng, Xiang; Firczuk, Helena; Pietroni, Paola; Westbrook, Richard; Dacheux, Estelle; Mendes, Pedro; McCarthy, John E.G.

    2017-01-01

    Gene expression noise influences organism evolution and fitness. The mechanisms determining the relationship between stochasticity and the functional role of translation machinery components are critical to viability. eIF4G is an essential translation factor that exerts strong control over protein synthesis. We observe an asymmetric, approximately bell-shaped, relationship between the average intracellular abundance of eIF4G and rates of cell population growth and global mRNA translation, with peak rates occurring at normal physiological abundance. This relationship fits a computational model in which eIF4G is at the core of a multi-component–complex assembly pathway. This model also correctly predicts a plateau-like response of translation to super-physiological increases in abundance of the other cap-complex factors, eIF4E and eIF4A. Engineered changes in eIF4G abundance amplify noise, demonstrating that minimum stochasticity coincides with physiological abundance of this factor. Noise is not increased when eIF4E is overproduced. Plasmid-mediated synthesis of eIF4G imposes increased global gene expression stochasticity and reduced viability because the intrinsic noise for this factor influences total cellular gene noise. The naturally evolved eIF4G gene expression noise minimum maps within the optimal activity zone dictated by eIF4G's mechanistic role. Rate control and noise are therefore interdependent and have co-evolved to share an optimal physiological abundance point. PMID:27928055

  14. Overweight, air and noise pollution: Universal risk factors for pediatric pre-hypertension

    Directory of Open Access Journals (Sweden)

    Roya Kelishadi

    2011-01-01

    Prevention and control of the modifiable risk factors of pre-HTN from prenatal period can have long-term health impact on primordial and primary prevention of chronic non-communicable diseases. This review presents a general view on the diagnosis, prevalence and etiology of pre-HTN along with practical measures for its prevention and control.

  15. Factors Affecting Pupils' Noise Annoyance in Schools: The Building and Testing of Models

    Science.gov (United States)

    Boman, Eva; Enmarker, Ingela

    2004-01-01

    This article reports two studies intended to develop and assess conceptual models of how different factors mediate and moderate the annoyance reaction in school environments. In the first, a survey of 207 pupils was conducted where assumptions about mediators and moderators were formulated and tested. In the best model, general sensitivity and…

  16. An analysis of harmful factors to storage stability of the reduced metallic fuel produced by the advanced spent fuel management process

    Energy Technology Data Exchange (ETDEWEB)

    Ju, J. S.; You, G. S.; Cho, I. J.; Kook, D. H.; Lee, J. C.; Seo, G. S.; Lee, E. P.; Seo, H. S. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-03-01

    This study was performed for the selection of alloying elements to make the metallic fuel alloys having a good stability to oxidation. Harmful factors on oxidation were also analyzed. Several basic properties such as microstructure, immiscibility, thermal and fission product effects were surveyed. The oxidation properties of metal uranium and uranium alloys were also studied. The results from this study are applicable to the selection of the alloying elements to stabilize the reduced uranium metal in the 2nd year research in phase 2, and also do an important role to increase the storage temperature. 29 refs., 37 figs., 5 tabs. (Author)

  17. Microelectromechanical System (MEMS) Gyroscope Noise Analysis and Scale Factor Characterization over Temperature Variation

    Science.gov (United States)

    2016-07-01

    bias sensitivity indicate that by multiplying the sensitivity coefficient by the current measured temperature, then subtracting that voltage value ...actual scale factors measured are slightly below the manufacturer’s nominal value of 0.012 V/°/s.) Approved for public release; distribution is...deviation value when tau was 3600 s, or 1 h. The results for both trials are presented in Table 3. Table 3 Rate random walk (°/h3/2) calculated using

  18. Noise sensitivity and sleep disturbance

    NARCIS (Netherlands)

    Laszlo, H.E.; Janssen, S.A.; Babisch, W.; Hansell, A.L.

    2012-01-01

    It has been shown that noise induced health effects are strongly related to non-acoustical factors such as noise sensitivity. It is a stable personality trait and it can be conceptualised as a causal pathway confounder and/or effect modifier between noise and health. Furthermore noise sensitivity pa

  19. Materials for fuel cells

    Directory of Open Access Journals (Sweden)

    Sossina M Haile

    2003-03-01

    Full Text Available Because of their potential to reduce the environmental impact and geopolitical consequences of the use of fossil fuels, fuel cells have emerged as tantalizing alternatives to combustion engines. Like a combustion engine, a fuel cell uses some sort of chemical fuel as its energy source but, like a battery, the chemical energy is directly converted to electrical energy, without an often messy and relatively inefficient combustion step. In addition to high efficiency and low emissions, fuel cells are attractive for their modular and distributed nature, and zero noise pollution. They will also play an essential role in any future hydrogen fuel economy.

  20. Electricity production by a microbial fuel cell fueled by brewery wastewater and the factors in its membrane deterioration

    Institute of Scientific and Technical Information of China (English)

    Afşin Y. Çetinkaya; Emre Oğuz Köroğlu; Neslihan Manav Demir; Derya Yılmaz Baysoy; Bestamin Özkaya; Mehmet Çakmakçı

    2015-01-01

    Electricity production from brewery wastewater using dual-chamber microbial fuel cells (MFCs) with a tin-coated copper mesh in the anode was investigated by changing the hydraulic retention time (HRT). The MFCs were fed with wastewater samples from the inlet (inflow, MFC-1) and outlet (outflow, MFC-2) of an anaerobic digester of a brewery wastewater treatment plant. Both chemical oxygen demand removal and current density were improved by decreasing HRT. The best MFC performance was with an HRT of 0.5 d. The maximum power densities of 8.001 and 1.843 µW/cm2 were obtained from reactors MFC-1 and MFC-2, respectively. Microbial diversity at different condi-tions was studied using PCR-DGGE profiling of 16S rRNA fragments of the microorganisms from the biofilm on the anode electrode. The MFC reactor had mainlyGeobacter,Shewanella, andClostridium species, and some bacteria were easily washed out at lower HRTs. The fouling characteristics of the MFC Nafion membrane and the resulting degradation of MFC performance were examined. The ion exchange capacity, conductivity, and diffusivity of the membrane decreased significantly after foul-ing. The morphology of the Nafion membrane and MFC degradation were studied using scanning electron microscopy and attenuated total reflection-Fourier transform infrared spectroscopy.

  1. Emission factors of air pollutants from CNG-gasoline bi-fuel vehicles: Part II. CO, HC and NOx.

    Science.gov (United States)

    Huang, Xiaoyan; Wang, Yang; Xing, Zhenyu; Du, Ke

    2016-09-15

    The estimation of emission factors (EFs) is the basis of accurate emission inventory. However, the EFs of air pollutants for motor vehicles vary under different operating conditions, which will cause uncertainty in developing emission inventory. Natural gas (NG), considered as a "cleaner" fuel than gasoline, is increasingly being used to reduce combustion emissions. However, information is scarce about how much emission reduction can be achieved by motor vehicles burning NG (NGVs) under real road driving conditions, which is necessary for evaluating the environmental benefits for NGVs. Here, online, in situ measurements of the emissions from nine bi-fuel vehicles were conducted under different operating conditions on the real road. A comparative study was performed for the EFs of black carbon (BC), carbon monoxide (CO), hydrocarbons (HCs) and nitrogen oxides (NOx) for each operating condition when the vehicles using gasoline and compressed NG (CNG) as fuel. BC EFs were reported in part I. The part II in this paper series reports the influence of operating conditions and fuel types on the EFs of CO, HC and NOx. Fuel-based EFs of CO showed good correlations with speed when burning CNG and gasoline. The correlation between fuel-based HC EFs and speed was relatively weak whether burning CNG or gasoline. The fuel-based NOx EFs moderately correlated with speed when burning CNG, but weakly correlated with gasoline. As for HC, the mileage-based EFs of gasoline vehicles are 2.39-12.59 times higher than those of CNG vehicles. The mileage-based NOx EFs of CNG vehicles are slightly higher than those of gasoline vehicles. These results would facilitate a detailed analysis of the environmental benefits for replacing gasoline with CNG in light duty vehicles. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. 燃料电池汽车空辅系统噪声有源控制技术%Active Noise Control Technology of Air Auxiliary System in Fuel Cell Vehicles

    Institute of Scientific and Technical Information of China (English)

    胡佳杰; 左曙光; 何吕昌; 张孟浩

    2013-01-01

      燃料电池汽车(FCV)的动力系统及噪声特性与传统汽车相比有着很大差异,其中空气辅助系统已成为主要的噪声源。虽然有源噪声控制(ANC)是近年来的研究热点;但是,由于噪声源与环境的时变性,对空辅系统的中低频段噪声更有效的对策是使用自适应有源噪声控制技术(AANC)。在归纳总结有源噪声控制技术的发展进程及基本原理的基础上,阐述近年来有源噪声控制的研究现状,并重点分析关注自适应算法的研究进展;由此对自适应有源噪声控制在燃料电池汽车空辅系统减振降噪方面的应用前景进行预测和展望。%The power system and its noise characteristic of Fuel Cell Vehicle (FCV) are quite different from those of traditional cars. In FCV, the air auxiliary system becomes one of the main noise sources. In recent years, active noise control (ANC) has become a research focus. It has advantages for the traditional passive noise control in middle-and low-frequency range. However, because of the time-variation property of noise sources and environments, it is necessary to use adaptive active noise control (AANC) in middle-and low-frequency noise control of the air auxiliary system in FCV. In this paper, the development progress of ANC technology was summarized, and the research of ANC in recent years was expatiated. Analysis was focused on the research progress of adaptive algorithm. Finally, the prospect of the ANNC application in the field of vibration and noise reduction of the air auxiliary system in FCV was forecasted.

  3. Cooking with Fire: The Mutagenicity- and PAH-Emission Factors of Solid-Fuel Cookstoves

    Science.gov (United States)

    Emissions from solid fuels used for cooking cause ~4 million premature deaths per year. Advanced solid-fuel cookstoves are a potential solution, but they should be assessed by appropriate performance indicators, including biological effects. We evaluated two categories of solid...

  4. Critical factors in transitioning from fuel cell to cold fusion technology

    Energy Technology Data Exchange (ETDEWEB)

    Mcgraw, T.F.; Davis, R.R.

    1998-07-01

    The fuel cell industry possesses much of the required manufacturing equipment and knowledge-base (e.g., proton conduction and hydrogen safety) necessary to develop cold fusion systems. Key factors in making a transition to cold fusion technology are discussed. Loading of reaction material can be provided by electrolytic charging and high gas over-pressure. Effective pressures over 10,000 atmospheres are required in cold fusion systems, giving a loading of H/M = 1; and a combination of loading methods is highly desirable. Systems must be designed to provide continuous flow of hydrogen ions ({much{underscore}gt}10{sup 17}/sec for ten kilowatts), with an input power source of 50 watts (est.). Cold fusion experiments have shown that helium is formed during the reaction, and physical changes occur in the reaction material. These revelations impact design and operation of cold fusion systems, as the reaction material must be replaced periodically, while the systems must maintain integrity during operation. Safety and cost are also highly important considerations.

  5. Enhancing factors of electricity generation in a microbial fuel cell using Geobacter sulfurreducens.

    Science.gov (United States)

    Kim, Mi-Sun; Cha, Jaehwan; Kim, Dong-Hoon

    2012-10-01

    In this study, we investigated various cultural and operational factors to enhance electricity generation in a microbial fuel cell (MFC) using Geobacter sulfurreducens. The pure culture of G. sulfurreducens was cultivated using various substrates including acetate, malate, succinate, and butyrate, with fumarate as an electron acceptor. Cell growth was observed only in acetate-fed medium, when the cell concentrations increased 4-fold for 3 days. A high acetate concentration suppressed electricity generation. As the acetate concentration was increased from 5 to 20 mM, the power density dropped from 16 to 13 mW/m2, whereas the coulombic efficiency (CE) declined by about half. The immobilization of G. sulfurreducens on the anode considerably reduced the enrichment period from 15 to 7 days. Using argon gas to create an anaerobic condition in the anode chamber led to increased pH, and electricity generation subsequently dropped. When the plain carbon paper cathode was replaced by Pt-coated carbon paper (0.5 mg Pt/cm2), the CE increased greatly from 39% to 83%.

  6. Numerical Studies on Heat Release Rate in Room Fire on Liquid Fuel under Different Ventilation Factors

    Directory of Open Access Journals (Sweden)

    N. Cai

    2012-01-01

    Full Text Available Heat release rate (HRR of the design fire is the most important parameter in assessing building fire hazards. However, HRR in room fire was only studied by computational fluid dynamics (CFD in most of the projects determining fire safety provisions by performance-based design. In contrast to ten years ago, officers in the Far East are now having better knowledge of CFD. Two common questions are raised on CFD-predicted results on describing free boundaries; and on computing grid size. In this work, predicting HRR by the CFD model was justified with experimental room pool fire data reported earlier. The software fire dynamics simulator (FDS version 5 was selected as the CFD simulation tool. Prescribed input heating rate based on the experimental results was used with the liquid fuel model in FDS. Five different free boundary conditions were investigated to predict HRR. Grid sensitivity study was carried out using one stretched mesh and multiple uniform meshes with different grid sizes. As it is difficult to have the entire set of CFD predicted results agreed with experiments, macroscopic flow parameters on the mass flow rate through door opening predicted by CFD were also justified by another four conditions with different ventilation factors.

  7. Lower Hearing Threshold by Noise

    Institute of Scientific and Technical Information of China (English)

    龙长才; 邵峰; 张燕萍; 秦佑国

    2004-01-01

    We demonstrate that noise can be a benefit factor that enables us to hear weaker signals. We measured the hearing thresholds of subjects for pure tone in different noise levels. The results show that pure tone thresholds with noise of some levels are lower than that without noise. The largest down-shift of the threshold by noise among the examined subjects is 5. 7dB, and the smallest is 1.7dB.

  8. Exact Calculation of Noise Maps and g-Factor in GRAPPA using a k-space Analysis

    CERN Document Server

    Rabanillo, Iñaki; Alberola-López, Carlos; Hernando, Diego

    2016-01-01

    Noise characterization in MRI has multiple applications, including quality assurance and protocol optimization. It is particularly important in the presence of parallel imaging acceleration, where the noise distribution can contain severe spatial heterogeneities. If the parallel imaging reconstruction is a linear process, an exact noise analysis is possible by taking into account the correlations between all the samples involved. However, for k-space based techniques like GRAPPA, the exact analysis has been considered computationally prohibitive due to the very large size of the noise covariance matrices required to characterize the noise propagation from k-space to image-space. Previous methods avoid this computational burden by approximating the GRAPPA reconstruction as a pixel-wise linear operation performed in the image-space. However, these methods are not exact in the presence of non-uniform k-space undersampling (e.g.: containing a calibration region). For this reason, in this work we develop an exact ...

  9. Effect of Attitudinal, Situational and Demographic Factors on Annoyance Due to Environmental Vibration and Noise from Construction of a Light Rapid Transit System.

    Science.gov (United States)

    Wong-McSweeney, Daniel; Woodcock, James; Waddington, David; Peris, Eulalia; Koziel, Zbigniew; Moorhouse, Andy; Redel-Macías, María Dolores

    2016-12-14

    The aim of this paper is to determine what non-exposure factors influence the relationship between vibration and noise exposure from the construction of a Light Rapid Transit (LRT) system and the annoyance of nearby residents. Noise and vibration from construction sites are known to annoy residents, with annoyance increasing as a function of the magnitude of the vibration and noise. There is not a strong correlation between exposure and levels of annoyance suggesting that factors not directly related to the exposure may have an influence. A range of attitudinal, situational and demographic factors are investigated with the aim of understanding the wide variation in annoyance for a given vibration exposure. A face-to-face survey of residents (n = 350) near three sites of LRT construction was conducted, and responses were compared to semi-empirical estimates of the internal vibration within the buildings. It was found that annoyance responses due to vibration were strongly influenced by two attitudinal variables, concern about property damage and sensitivity to vibration. Age, ownership of the property and the visibility of the construction site were also important factors. Gender, time at home and expectation of future levels of vibration had much less influence. Due to the measurement methods used, it was not possible to separate out the effects of noise and vibration on annoyance; as such, this paper focusses on annoyance due to vibration exposure. This work concludes that for the most cost-effective reduction of the impact of construction vibration and noise on the annoyance felt by a community, policies should consider attitudinal factors.

  10. Characterization of control rod worths and fuel rod power peaking factors in the university of Utah TRIGA Mark I reactor

    OpenAIRE

    Alroumi Fawaz; Kim Donghoon; Schow Ryan; Jevremovic Tatjana

    2016-01-01

    Control rod reactivity (worths) for the three control rods and fuel rod power peaking factors in the University of Utah research reactor (100 kW TRIGA Mark I) are characterized using the AGENT code system and the results described in this paper. These values are compared to the MCNP6 and existing experimental measurements. In addition, the eigenvalue, neutron spatial flux distributions and reaction rates are analyzed and discussed. The AGENT code system is ...

  11. Factors influencing household uptake of improved solid fuel stoves in low- and middle-income countries: a qualitative systematic review.

    Science.gov (United States)

    Debbi, Stanistreet; Elisa, Puzzolo; Nigel, Bruce; Dan, Pope; Eva, Rehfuess

    2014-08-13

    Household burning of solid fuels in traditional stoves is detrimental to health, the environment and development. A range of improved solid fuel stoves (IS) are available but little is known about successful approaches to dissemination. This qualitative systematic review aimed to identify factors that influence household uptake of IS in low- and middle-income countries. Extensive searches were carried out and studies were screened and extracted using established systematic review methods. Fourteen qualitative studies from Asia, Africa and Latin-America met the inclusion criteria. Thematic synthesis was used to synthesise data and findings are presented under seven framework domains. Findings relate to user and stakeholder perceptions and highlight the importance of cost, good stove design, fuel and time savings, health benefits, being able to cook traditional dishes and cleanliness in relation to uptake. Creating demand, appropriate approaches to business, and community involvement, are also discussed. Achieving and sustaining uptake is complex and requires consideration of a broad range of factors, which operate at household, community, regional and national levels. Initiatives aimed at IS scale up should include quantitative evaluations of effectiveness, supplemented with qualitative studies to assess factors affecting uptake, with an equity focus.

  12. Fuel flexible fuel injector

    Science.gov (United States)

    Tuthill, Richard S; Davis, Dustin W; Dai, Zhongtao

    2015-02-03

    A disclosed fuel injector provides mixing of fuel with airflow by surrounding a swirled fuel flow with first and second swirled airflows that ensures mixing prior to or upon entering the combustion chamber. Fuel tubes produce a central fuel flow along with a central airflow through a plurality of openings to generate the high velocity fuel/air mixture along the axis of the fuel injector in addition to the swirled fuel/air mixture.

  13. Analysis of factors affecting the implementation of back-end nuclear fuel cycle policy in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yung Myung; Yang, Maeng Ho; Kim, Hyun Joon; Chung, Hwan Sam; Oh, Keun Bae; Lee, Byung OoK; Ko, Han Suk; Song, Ki Dong; Lee, Man Ki; Moon, Ki Hwan; Lee, Han Myung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-01-01

    In this study, the back-end nuclear fuel cycle acceptability is surveyed and analyzed in the following three aspects. To begin with, the future political situation and energy-environmental issues are analyzed as part of the socio-economic aspect. Secondly, the domestic situation of nuclear industries and the fuel cycle policy of foreign countries are surveyed as the technical aspect. Finally, NPT, IAEA safeguards and nuclear export control regimes are analyzed as the institutional aspect. The unification period of South and North Korea also will greatly affect the implementation of back-end fuel cycle policy, and public attitudes will affect the acquisition of site, construction, and operation of nuclear facilities. An effort to release international restrictions on the back-end fuel cycle is also required to accelerate the implementation of the policy. In this regard, the back-end fuel cycle policy should be clear-cut to avoid misunderstanding with respect to nuclear proliferation. Importantly, agreements with foreign countries should be amended at a mutual equivalent level. (Author) 30 refs., 5 figs., 25 tabs.

  14. Assessing the emission factors of low-pour-fuel-oil and diesel in steam boilers

    Directory of Open Access Journals (Sweden)

    Ohijeagbon, I.O.

    2012-12-01

    Full Text Available The purpose of this study is to examine the emissions effects resulting from the use of low pour fuel oil (LPFO and diesel fuels in industrial steam boilers operation. The method of ultimate analysis of the products of combustion and emissions of pollutant analysis were used to estimate the annual rate of emissions of boilers. The results shows that the levels of uncontrolled boiler emissions on the environment can lead to increased greenhouse effects, global warming, and pollution and toxilogical impacts on human health. Only carbon monoxide emission was found to vary with the levels of oxygen generation in the products of combustion, while other substances were generally in relation to constituents and rates of consumption of fuel.

  15. Concurrent Phosphorus Recovery and Energy Generation in Mediator-Less Dual Chamber Microbial Fuel Cells: Mechanisms and Influencing Factors.

    Science.gov (United States)

    Almatouq, Abdullah; Babatunde, Akintunde O

    2016-03-29

    This study investigated the mechanism and key factors influencing concurrent phosphorus (P) recovery and energy generation in microbial fuel cells (MFC) during wastewater treatment. Using a mediator-less dual chamber microbial fuel cell operated for 120 days; P was shown to precipitate as struvite when ammonium and magnesium chloride solutions were added to the cathode chamber. Monitoring data for chemical oxygen demand (COD), pH, oxidation reduction potential (ORP) and aeration flow rate showed that a maximum 38% P recovery was achieved; and this corresponds to 1.5 g/L, pH > 8, -550 ± 10 mV and 50 mL/min respectively, for COD, pH(cathode), ORP and cathode aeration flow rate. More importantly, COD and aeration flow rate were shown to be the key influencing factors for the P recovery and energy generation. Results further show that the maximum P recovery corresponds to 72 mW/m² power density. However, the energy generated at maximum P recovery was not the optimum; this shows that whilst P recovery and energy generation can be concurrently achieved in a microbial fuel cell, neither can be at the optimal value.

  16. Factors That Facilitate Or Hinder Fuel-Saving Initiatives and Technology

    Science.gov (United States)

    2015-12-01

    technology at various levels to support fuel efficiency. During the literature review , many of the theories pertaining to the use and acceptance of...Morris, M. (1996). User acceptance of information technology : Theories and models . Annual Review of Information Science and Technology , 31, 3–32...7 B. TECHNOLOGY ACCEPTANCE MODEL ...........................................8 1. Evolution of TAM

  17. Inspection of copper canisters for spent nuclear fuel by means of ultrasonic array system. Modelling, defect detection and grain noise estimation

    Energy Technology Data Exchange (ETDEWEB)

    Wu Ping; Stepinski, T. [Uppsala Univ., (Sweden). Dept. of Material Science

    1998-07-01

    The work presented in the report has been split into three overlapping tasks which have the following objectives: (1) development of beam-forming tools, and verification of modeling tools; (2) investigation of detection and resolution limits; (3) evaluation of attenuation, estimation and suppression of grain noise. For beam-forming tools, a method of designing steered and/or focused beams in immersed solids is presented based on geometrical acoustics. Presently, the beam designs are only related to delays but not to apodization. These focused, steered beams are intended to be used for sizing defects and inspecting the regions close to canisters outer walls. The modeling tool developed previously for simulating elastic fields radiated by planar arrays into immersed solids has been verified by comparing with the results obtained from PASS, a software developed by Dr. Didier Cassereau, France. The results from our modeling tool are in excellent agreement with those from PASS. Since the array coming with the ALLIN ultrasonic array system is not planar, but cylindrically curved in elevation, and it works not in transmission mode, but in pulse echo mode, the above modeling tool for the planar arrays cannot be applied directly. Therefore, the modeling tool has been upgraded for the ALLIN array. The theory underlying this modeling tool is the extended angular spectrum approach (ASA) which was developed based on the conventional ASA that only applies to planar sources. Experimental verification of the modeling tool has shown that the results from the tool agree very well with the measurements. To quantify the fields from the ALLIN array and to facilitate the comparison of simulated results with the measured ones, the ALLIN array system has been calibrated based on the existing functionality, and an analytical model has been proposed for simulating measured acoustic echo pulses. To investigate the detection and resolution limits, we have carried out a series of experiments

  18. DOE perspective on fuel cells in transportation

    Energy Technology Data Exchange (ETDEWEB)

    Kost, R.

    1996-04-01

    Fuel cells are one of the most promising technologies for meeting the rapidly growing demand for transportation services while minimizing adverse energy and environmental impacts. This paper reviews the benefits of introducing fuel cells into the transportation sector; in addition to dramatically reduced vehicle emissions, fuel cells offer the flexibility than use petroleum-based or alternative fuels, have significantly greater energy efficiency than internal combustion engines, and greatly reduce noise levels during operation. The rationale leading to the emphasis on proton-exchange-membrane fuel cells for transportation applications is reviewed as are the development issues requiring resolution to achieve adequate performance, packaging, and cost for use in automobiles. Technical targets for power density, specific power, platinum loading on the electrodes, cost, and other factors that become increasingly more demanding over time have been established. Fuel choice issues and pathways to reduced costs and to a renewable energy future are explored. One such path initially introduces fuel cell vehicles using reformed gasoline while-on-board hydrogen storage technology is developed to the point of allowing adequate range (350 miles) and refueling convenience. This scenario also allows time for renewable hydrogen production technologies and the required supply infrastructure to develop. Finally, the DOE Fuel Cells in Transportation program is described. The program, whose goal is to establish the technology for fuel cell vehicles as rapidly as possible, is being implemented by means of the United States Fuel Cell Alliance, a Government-industry alliance that includes Detroit`s Big Three automakers, fuel cell and other component suppliers, the national laboratories, and universities.

  19. Noise-control needs in the developing energy technologies

    Energy Technology Data Exchange (ETDEWEB)

    Keast, D.N.

    1978-03-01

    The noise characteristics of existing energy conversion technologies, e.g., from obtaining and processing fossil fuels to power plants operations, and of developing energy technologies (wind, geothermal sources, solar energy or fusion systems) are discussed in terms of the effects of noise on humans, animals, structures, and equipment and methods for noise control. Regulations for noise control are described. Recommendations are made for further research on noise control and noise effects. (LCL)

  20. Noise factor of a high-speed cinematography system; Facteur de bruit d'une chaine de cinematographie ultrarapide: application a la fusion par confinement inertiel

    Energy Technology Data Exchange (ETDEWEB)

    Secroun, A

    2000-03-01

    Inertial confinement fusion simulates in a laboratory the thermodynamic state of the center of stars, thus leading to the determination of stellar parameters. In order to reach that aim, high-speed cinematography brings up instruments specifically adapted to picosecond measurement, for which it is necessary to know the final precision. A model of the noise factor of the instruments under study is introduced and confronted to the experimental results obtained. (authors)

  1. Noise sensitivity in relation to baseline arousal, physiological response and psychological features to noise exposure during task performance

    NARCIS (Netherlands)

    White, K.; Hofman, W.F.; van Kamp, I.

    2010-01-01

    People who consider themselves sensitive to noise, experience more noise annoyance, sleep disturbance and reduced daytime performance. Besides psychological factors, an association with cardiovascular reactions during noise has been established in noise sensitives. Decreased efficiency of the parasy

  2. Effects of traffic noise

    Energy Technology Data Exchange (ETDEWEB)

    Gottlob, D.

    1986-02-01

    One of the main sources of noise is road traffic. In 1984 there were over 25 million cars, 1.2 million lorries, 1.3 million motor cycles and 1.6 million mopeds using our roads. Opinion polls showed that 21% of the population felt that they were affected by traffic noise as a nuisance factor. An outline of the effects of this noise on the affected population is given, illustrated by diagrams. Details about noise emissions (drive-past level) of the different types of vehicles in city traffic are stated and the effects of noise described. The author goes into the nuisance effect (noise is not a physical factor, but a psychosocial one), changes in behaviour (ways of speaking, reduction of stress on households in proportion to rising income and higher educational levels) and the consequences for health (the reaction of the body to noise is primarily a consequence of the psychosomatic organisation of ow bodies). In conclusion, the author deals with the subjective efficiency of noise protection measures. (HWJ).

  3. Factors affecting the performance of microbial fuel cells for sulfur pollutants removal.

    Science.gov (United States)

    Zhao, Feng; Rahunen, Nelli; Varcoe, John R; Roberts, Alexander J; Avignone-Rossa, Claudio; Thumser, Alfred E; Slade, Robert C T

    2009-03-15

    A microbial fuel cell (MFC) has been developed for removal of sulfur-based pollutants and can be used for simultaneous wastewater treatment and electricity generation. This fuel cell uses an activated carbon cloth+carbon fibre veil composite anode, air-breathing dual cathodes and the sulfate-reducing species Desulfovibrio desulfuricans. 1.16gdm(-3) sulfite and 0.97gdm(-3) thiosulfate were removed from the wastewater at 22 degrees C, representing sulfite and thiosulfate removal conversions of 91% and 86%, respectively. The anode potential was controlled by the concentration of sulfide in the compartment. The performance of the cathode assembly was affected by the concentration of protons in the cation-exchanging ionomer with which the electrocatalyst is co-bound at the three-phase (air, catalyst and support) boundary.

  4. Emission factors of gaseous pollutants from recent kerosene space heaters and fuels available in France in 2010.

    Science.gov (United States)

    Carteret, M; Pauwels, J-F; Hanoune, B

    2012-08-01

    Laboratory measurements of the gaseous emission factors (EF) from two recent kerosene space heaters (wick and injector) with five different fuels have been conducted in an 8-m(3) environmental chamber. The two heaters tested were found to emit mainly CO(2), CO, NO, NO(2), and some volatile organic compounds (VOCs). NO(2) is continuously emitted during use, with an EF of 100-450 μg per g of consumed fuel. CO is normally emitted mainly during the first minutes of use (up to 3 mg/g). Formaldehyde and benzene EFs were quantified at 15 and 16 μg/g, respectively, for the wick heater. Some other VOCs, such as 1,3-butadiene, were detected with lower EFs. We demonstrated the unsuitability of a 'biofuel' containing fatty acid methyl esters for use with the wick heater, and that the accumulation of soot on the same heater, whatever the fuel, leads to a dramatic increase in the CO EF, up to 16 mg/g, which could be responsible for chronic and acute CO intoxications. Our results show that in spite of new technologies and emission standards for unvented kerosene space heaters, as well as for the fuels, the use of these heaters in indoor environments still leads to NO(x) levels in excess of current health recommendations. Whereas injection heaters generate more nitrogen oxides than wick heaters, prolonged use of the latter leads to a soot buildup, concomitant with high CO emissions, which could be responsible for acute and chronic intoxications. The use of a biofuel in a wick heater is also of concern. Maintenance of the heaters and adequate ventilation of the room during use of kerosene space heaters are therefore of prime importance to reduce personal exposure. © 2011 John Wiley & Sons A/S.

  5. 噪声作业场所环境危险因素对噪声性听力损失的影响%Effect of environmental risk factors in occupational noise exposure on noise-induced hearing loss

    Institute of Scientific and Technical Information of China (English)

    刘移民; 李旭东; 李永胜; 郭晓; 肖吕武; 肖启华; 何国权; 吴琳

    2008-01-01

    Objective To observe the effect of environmental risk factors in occupational noise exposure on hearing loss and find out the susceptible population of noise induced heating loss(NIHL).Methods A case-control study was designed to study the effect of environmental risk factors on NIHL 2400 workers exposed to 75~120 dB noises from an air conditioning factory in southern China served as the subjects.202 workers were selected from 10% of population with the maximum hearing shift of the left ear to 3000 Hz noises as the NIHL susceptible group while 204 workers from 10%of population with the least heating shift as the NIHL tolerant group.A questionnaire was designed to carry out an investigation,and an occupational health survey was used to identify the occupational risk factors which might affect the hearing system.The univariate analysis and multivariate analysis were used to observe the effect of environmental risk factors on NIHL.Results The results of univariate analysis showed that smoking,alcohol drinking,organic solvent,heavy metal,heat,dust were significantly was associated with NIHL(P<0.05).Multivariate analysis showed that only heat was associated with NIHL(P<0.05),and OR value was 1.804(95%CI:1.101~2.958).Conclusion Exposure to heat may be a high risk factor of NIHL.%目的 探讨噪声作业场所除噪声外其他环境危险因素对个体听力损失的影响,从环境因素出发寻找噪声性听力损失(NIHL)的高危易感人群.方法 采用病例对照研究方法,选择南方某市某大型空调生产企业连续性噪声暴露强度在75~120 dB范围内2400名作业工人为研究对象,比较同一噪声暴露组内噪声作业人员的左耳3000 Hz频段听阈位移情况,筛选出听阈位移最大的10%个体作为本研究的易感人群组,共202例;听阈位移最小的10%个体作为耐受人群组,共204例.并对两组人群进行作业场所职业卫生调查和问卷调查,通过单因素和多因素分析环境因素对

  6. FUEL CELL ELECTRODE MATERIALS

    Science.gov (United States)

    FUEL CELL ELECTRODE MATERIALS. RAW MATERIAL SELECTION INFLUENCES POLARIZATION BUT IS NOT A SINGLE CONTROLLING FACTOR. AVAILABLE...DATA INDICATES THAT AN INTERRELATIONSHIP OF POROSITY, AVERAGE PORE VOLUME, AND PERMEABILITY CONTRIBUTES TO ELECTRODE FUEL CELL BEHAVIOR.

  7. Noise Pollution

    Science.gov (United States)

    ... Search Clean Air Act Overview Share Facebook Twitter Google+ Pinterest Contact Us Clean Air Act Title IV - ... noises in the community (from your neighbor, boom cars, lawn equipment, etc.) and from commercial businesses (factory, ...

  8. Statistical modelling of forest fire danger rating based on meteorological, topographical and fuel factors in the Republic of Korea

    Science.gov (United States)

    Won, M.; Yoon, S.; Jang, K.; Lim, J.

    2016-12-01

    Most of fires were human-caused fires in Korea, but meteorological factors are also big contributors to fire behavior and its spread. Thus, meteorological factors as well as social factors were considered in the fire danger rating systems. This study aims to develop an advanced Korean Forest Fire Danger Rating System (KFFDRS) using weather data of automatic mountain meteorology observation systems(AMOSs) to support forest fire prevention strategy in South Korea. The KFFDRS consists of three, 10-scale indices: daily weather index (DWI), fuel model index (FMI), and topography model index (TMI). DWI represents the meteorological characteristics, such as humidity (relative and effective), temperature and wind speed, and we integrated nine logistic regression models of the past into one national model. One integrated national model is [1+exp{2.706+(0.088×maximum temperature)-(0.055×relative humidity)-(0.023×effective humidity)-(0.104×mean wind speed)}-1]-1 and all weather variables significantly (pfusion of mountain weather data with 55 random sampling in forest fire event days. One integrated national model showed 10% high accuracy than nine logistic regression models when it is applied fused mountain weather data. These findings would be necessary for the policy makers in the Republic of Korea for the prevention of forest fires.

  9. Soil-geochemical factors of rocket fuel migration in the landscape

    Science.gov (United States)

    Krechetov, P. P.; Kasimov, N. S.; Koroleva, T. V.

    2015-10-01

    The effect of different soil-geochemical factors on the migration of asymmetric dimethylhydrazine (UDMH) in the landscape has been studied. Experimental studies have been performed on soil and rock samples with specified parameters of the material composition. The effect of organic matter, acid-base properties, particle size distribution, and mineralogy on the decrease in the concentration of UDMH in equilibrium solutions has been studied. It has been found that the soil-geochemical factors are arranged in the following series according to the effect on UDMH mobility: acid-base properties > organic matter content > clay fraction mineralogy > particle size distribution.

  10. Factors affecting fuel break effectiveness in the control of large fires on the Los Padres National Forest, California

    Science.gov (United States)

    Syphard, Alexandra D.; Keeley, Jon E.; Brennan, Teresa J.

    2011-01-01

    As wildfires have increased in frequency and extent, so have the number of homes developed in the wildland-urban interface. In California, the predominant approach to mitigating fire risk is construction of fuel breaks, but there has been little empirical study of their role in controlling large fires.We constructed a spatial database of fuel breaks on the Los Padres National Forest in southern California to better understand characteristics of fuel breaks that affect the behaviour of large fires and to map where fires and fuel breaks most commonly intersect. We evaluated whether fires stopped or crossed over fuel breaks over a 28-year period and compared the outcomes with physical characteristics of the sites, weather and firefighting activities during the fire event. Many fuel breaks never intersected fires, but others intersected several, primarily in historically fire-prone areas. Fires stopped at fuel breaks 46% of the time, almost invariably owing to fire suppression activities. Firefighter access to treatments, smaller fires and longer fuel breaks were significant direct influences, and younger vegetation and fuel break maintenance indirectly improved the outcome by facilitating firefighter access. This study illustrates the importance of strategic location of fuel breaks because they have been most effective where they provided access for firefighting activities.

  11. Analysis and Comparison Based on Component Stress Factor of Dual Active Bridge and Isolated Full Bridge Boost Converters for Bidirectional Fuel Cells Systems

    DEFF Research Database (Denmark)

    Pittini, Riccardo; Mira Albert, Maria del Carmen; Zhang, Zhe;

    2014-01-01

    This paper presents an analysis and comparison of isolated topologies for bidirectional fuel cell systems. The analyzed topologies are the dua l active bridge (DAB) and the isolated full bridge boost converter (IFBBC). The analysis is performed based on the component stress factor (CSF). Results ...

  12. Characterization of control rod worths and fuel rod power peaking factors in the university of Utah TRIGA Mark I reactor

    Directory of Open Access Journals (Sweden)

    Alroumi Fawaz

    2016-01-01

    Full Text Available Control rod reactivity (worths for the three control rods and fuel rod power peaking factors in the University of Utah research reactor (100 kW TRIGA Mark I are characterized using the AGENT code system and the results described in this paper. These values are compared to the MCNP6 and existing experimental measurements. In addition, the eigenvalue, neutron spatial flux distributions and reaction rates are analyzed and discussed. The AGENT code system is widely benchmarked for various reactor types and complexities in their geometric arrangements of the assemblies and reactor core material distributions. Thus, it is used as a base methodology to evaluate neutronics variables of the research reactor at the University of Utah. With its much shorter computation time than MCNP6, AGENT provides agreement with the MCNP6 within a 0.5 % difference for the eigenvalue and a maximum difference of 10% in the power peaking factor values. Differential and integral control rod worths obtained by AGENT show well agreement with MCNP6 and the theoretical model. However, regulating the control rod worth is somewhat overestimated by both MCNP6 and AGENT models when compared to the experimental/theoretical values. In comparison to MCNP6, the total control rod worths and shutdown margin obtained with AGENT show better agreement to the experimental values.

  13. Influence Factors of Audible Noise Caused by Corona Discharge on UHVDC Transmission Lines Under High Altitude Condition

    Institute of Scientific and Technical Information of China (English)

    TIAN Feng; YU Zhanqing; ZENG Rong; LIU Lei; LI Min; LI Ruihai

    2012-01-01

    Audible noises (AN) generated by corona discharges on ultra high voltage direct current (UHVDC) transmission lines is one of the key issues of UHVDC power projects. Experimental results were obtained synchronously by 10 Briiel & Kjeer outdoor AN instruments under the full-scale test lines in National Laboratory for UHV Technology in Kunming at an altitude of 2 100 m. Long-term statistical measurements of the AN level were performed almost 24 hours a day and 5 ~ 6 days a week in 2 years. Influences of voltage, line configurations, temperature and humidity on the characteristics of AN levels were analysed. The measurement results show that the AN level rises with increasing line voltage, decreasing minimum conductor height and increasing bundle radius. The pole spacing has no significant influence on the peak value of the AN level. The AN level varies about _+ 1 dB in the temperature range of 15~22℃, and no more than ±2 dB within 6.8~24.4 ℃. The results also indicate that in a relative low range of absolute humidity, about 5 ~ 7. 99 g/ma, the AN level fluctuates slightly at different measurement points. However, in a relative high absolute humidity range, about 8 ~ 11. 5 g/ma, the AN level decreases with the increase of absolute humidity.

  14. Turbine combustor with fuel nozzles having inner and outer fuel circuits

    Science.gov (United States)

    Uhm, Jong Ho; Johnson, Thomas Edward; Kim, Kwanwoo

    2013-12-24

    A combustor cap assembly for a turbine engine includes a combustor cap and a plurality of fuel nozzles mounted on the combustor cap. One or more of the fuel nozzles would include two separate fuel circuits which are individually controllable. The combustor cap assembly would be controlled so that individual fuel circuits of the fuel nozzles are operated or deliberately shut off to provide for physical separation between the flow of fuel delivered by adjacent fuel nozzles and/or so that adjacent fuel nozzles operate at different pressure differentials. Operating a combustor cap assembly in this fashion helps to reduce or eliminate the generation of undesirable and potentially harmful noise.

  15. Performance Factors and Sulfur Tolerance of Metal Supported Solid Oxide Fuel Cells with Nanostructured Ni:GDC Infiltrated Anodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Sudireddy, Bhaskar Reddy; Hagen, Anke

    2016-01-01

    stainless steel (FeCr) and showed excellent performance characteristics at 650°C with fuel utilization corrected area specific resistances of 0.35 Ωcm2 and 0.7 Ωcm2 respectively. The sulfur tolerance testing was performed by periodic addition of 2, 5, and 10 ppm H2S in hydrogen based fuel under...

  16. Longitudinal Study of Human Hearing: Its Relationship to Noise and Other Factors 2. Results from the First Three Years

    Science.gov (United States)

    1979-11-01

    rural Illinois school system. Am. J. Dis. Child., 80: 254-259. Eagles, E. 1., S. M. Wishik, L. G. Doerfler , W. Melnick, and H. S. Levine 1963 Hearing...sensitivity and related factors in children. Laryngoscope, Monograph Suppl., 1-143. Eagles, E. L., S. M. Wishik, and L. G. Doerfler 1967 Hearing

  17. An examination of the factors fueling migration amongst Community Service practitioners

    Directory of Open Access Journals (Sweden)

    Candice Reardon

    2014-01-01

    Full Text Available Background: Research is needed in order to understand the potential influence of the Bilateral Agreement between South Africa and the United Kingdom (UK, as well as other more recent international and local policies restricting movement of South African health workers abroad; and to determine what effect they have on the migration intentions and plans of health professionals in South Africa.Aim: The aims were to (1 explore the migration intentions and the factors that influence these intentions amongst Community Service (CS nurses and doctors; (2 explore their views and opinions about the Bilateral Agreement between the UK and South Africa (SA and other UK policies around the recruitment and employment of foreign health professionals; and (3 understand the impact of these policies on the migration plans of these CS doctors and nurses.Method: Qualitative focus groups and interviews were conducted with 23 CS doctors and nurses. To supplement this, 6 interviews were conducted with nurses and a doctor who had worked in the UK.Results: A higher disposition toward moving abroad was apparent amongst those who had experienced a challenging and frustrating CS year. Poor working conditions, including long work hours, high patient loads and inadequate resources and equipment, as well as low salaries and the perceived ambivalence of the government to the complaints of health practitioners, were influencing decisions to migrate abroad.Conclusion: The findings suggest that government efforts to better manage, recognise and respect the work and contribution of health professionals to the country would go a long way toward retaining health professionals.

  18. An examination of the factors fueling migration amongst Community Service practitioners

    Directory of Open Access Journals (Sweden)

    Candice Reardon

    2014-01-01

    Full Text Available Background: Research is needed in order to understand the potential influence of the Bilateral Agreement between South Africa and the United Kingdom (UK, as well as other more recent international and local policies restricting movement of South African health workers abroad; and to determine what effect they have on the migration intentions and plans of health professionals in South Africa.Aim: The aims were to (1 explore the migration intentions and the factors that influence these intentions amongst Community Service (CS nurses and doctors; (2 explore their views and opinions about the Bilateral Agreement between the UK and South Africa (SA and other UK policies around the recruitment and employment of foreign health professionals; and (3 understand the impact of these policies on the migration plans of these CS doctors and nurses.Method: Qualitative focus groups and interviews were conducted with 23 CS doctors and nurses. To supplement this, 6 interviews were conducted with nurses and a doctor who had worked in the UK.Results: A higher disposition toward moving abroad was apparent amongst those who had experienced a challenging and frustrating CS year. Poor working conditions, including long work hours, high patient loads and inadequate resources and equipment, as well as low salaries and the perceived ambivalence of the government to the complaints of health practitioners, were influencing decisions to migrate abroad.Conclusion: The findings suggest that government efforts to better manage, recognise and respect the work and contribution of health professionals to the country would go a long way toward retaining health professionals.

  19. Analysis of influence factors of freight vehicle fuel economy%影响货运车辆燃料经济性因素分析

    Institute of Scientific and Technical Information of China (English)

    孟兴凯; 张志芳; 曾诚; 阳冬波

    2013-01-01

    The structural performance factors and the using factors of truck play an important role on truck fuel economy.In this paper, the influence of engine, vehicle type, transmission system, lubrication oil, tires and other factors on the truck fuel economy are discussed.Driver operating procedures and envi-ronmental factors are introduced in details, when it comes to the effect of use factors on fuel economy.%货运车辆的结构性能因素和使用因素是燃料经济性的主要影响因素,文章详述了货运车辆的发动机、车型、传动系、润滑油以及轮胎等因素对燃料经济性的影响;另外还介绍了驾驶员驾驶技术及环境等因素对车辆燃料经济性的影响。

  20. Anthropogenic and technogenic factors of operational risk at hazardous industrial objects of fuel-power complex

    Science.gov (United States)

    Magid, S. I.; Arkhipova, E. N.; Kulichikhin, V. V.; Zagretdinov, I. Sh.

    2016-12-01

    Technogenic and anthropogenic accidence at hazardous industrial objects (HIO) in the Russian Federation has been considered. The accidence level at HIO, including power plants and network enterprises, is determined by anthropogenic reasons, so-called "human factor", in 70% of all cases. The analysis of incidents caused by personnel has shown that errors occur most often during accidental situations, launches, holdups, routine switches, and other effects on equipment controls. It has been demonstrated that skills needed to perform type and routine switches can be learned, to certain limits, on real operating equipment, while combating emergency and accidental situations can be learned only with the help of modern training simulators developed based on information technologies. Problems arising during the following processes have been considered: development of mathematical and software support of modern training equipment associated, in one way or another, with adequate power-generating object modeling in accordance with human operator specifics; modeling and/or simulation of the corresponding control and management systems; organization of the education system (functional supply of the instructor, education and methodological resources (EMR)); organization of the program-technical, scalable and adaptable, platform for modeling of the main and secondary functions of the training simulator. It has been concluded that the systemic approach principle on the necessity and sufficiency in the applied methodology allows to reproduce all technological characteristics of the equipment, its topological completeness, as well as to achieve the acceptable counting rate. The initial "rough" models of processes in the equipment are based on the normative techniques and equation coefficients taken from the normative materials as well. Then, the synthesis of "fine" models has been carried out following the global practice in modeling and training simulator building, i

  1. Airport noise and teratogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, L.D.; Layde, P.M.; Erickson, J.D.

    1979-07-01

    It has been suggested that exposure to high-noise levels near major airports may cause increased incidence of birth defects in the offspring of parents residing near these airports. Using data gathered in Metropolitan Atlanta during 1970 to 1972, we compared the rates of seventeen categories of defects in high- and low-noise census tracts. No significant differences were observed. However, when we subdivided the category of central nervous system defects into several subcategories of specific defects, we noted a significantly increased incidence of spina bifida without hydrocephalus in the high-noise areas. Because of the small number of cases associated with this finding we did a matched case-control study using all cases of central nervous system defects born during the years 1968 to 1976. No significantly increased risk for residents in the high-noise areas was noted in this study. It is our opinion that noise or other factors associated with residence near airports are unlikely to be important environmental teratogens.

  2. Magnetic field dependence of the internal quality factor and noise performance of lumped-element kinetic inductance detectors

    CERN Document Server

    Flanigan, Daniel; Abitbol, Maximilian H; Bryan, Sean; Cantor, Robin; Day, Peter K; Jones, Glenn; Mauskopf, Philip; McCarrick, Heather; Miller, Amber; Zmuidzinas, Jonas

    2016-01-01

    We present a technique for increasing the internal quality factor of kinetic inductance detectors (KIDs) by nulling ambient magnetic fields with a properly applied magnetic field. The KIDs used in this study are made from thin-film aluminum, they are mounted inside a light-tight package made from bulk aluminum, and they are operated near $150 \\, \\mathrm{mK}$. Since the thin-film aluminum has a slightly elevated critical temperature ($T_\\mathrm{c} = 1.4 \\, \\mathrm{K}$), it therefore transitions before the package ($T_\\mathrm{c} = 1.2 \\, \\mathrm{K}$), which also serves as a magnetic shield. On cooldown, ambient magnetic fields as small as approximately $30 \\, \\mathrm{\\mu T}$ can produce vortices in the thin-film aluminum as it transitions because the bulk aluminum package has not yet transitioned and therefore is not yet shielding. These vortices become trapped inside the aluminum package below $1.2 \\, \\mathrm{K}$ and ultimately produce low internal quality factors in the thin-film superconducting resonators. W...

  3. Speech intelligibility index predictions for young and old listeners in automobile noise: Can the index be improved by incorporating factors other than absolute threshold?

    Science.gov (United States)

    Saweikis, Meghan; Surprenant, Aimée M.; Davies, Patricia; Gallant, Don

    2003-10-01

    While young and old subjects with comparable audiograms tend to perform comparably on speech recognition tasks in quiet environments, the older subjects have more difficulty than the younger subjects with recognition tasks in degraded listening conditions. This suggests that factors other than an absolute threshold may account for some of the difficulty older listeners have on recognition tasks in noisy environments. Many metrics, including the Speech Intelligibility Index (SII), used to measure speech intelligibility, only consider an absolute threshold when accounting for age related hearing loss. Therefore these metrics tend to overestimate the performance for elderly listeners in noisy environments [Tobias et al., J. Acoust. Soc. Am. 83, 859-895 (1988)]. The present studies examine the predictive capabilities of the SII in an environment with automobile noise present. This is of interest because people's evaluation of the automobile interior sound is closely linked to their ability to carry on conversations with their fellow passengers. The four studies examine whether, for subjects with age related hearing loss, the accuracy of the SII can be improved by incorporating factors other than an absolute threshold into the model. [Work supported by Ford Motor Company.

  4. Spin-noise correlations and spin-noise exchange driven by low-field spin-exchange collisions

    Science.gov (United States)

    Dellis, A. T.; Loulakis, M.; Kominis, I. K.

    2014-09-01

    The physics of spin-exchange collisions have fueled several discoveries in fundamental physics and numerous applications in medical imaging and nuclear magnetic resonance. We report on the experimental observation and theoretical justification of spin-noise exchange, the transfer of spin noise from one atomic species to another. The signature of spin-noise exchange is an increase of the total spin-noise power at low magnetic fields, on the order of 1 mG, where the two-species spin-noise resonances overlap. The underlying physical mechanism is the two-species spin-noise correlation induced by spin-exchange collisions.

  5. How the user can influence particulate emissions from residential wood and pellet stoves: Emission factors for different fuels and burning conditions

    Science.gov (United States)

    Fachinger, Friederike; Drewnick, Frank; Gieré, Reto; Borrmann, Stephan

    2017-06-01

    For a common household wood stove and a pellet stove we investigated the dependence of emission factors for various gaseous and particulate pollutants on burning phase, burning condition, and fuel. Ideal and non-ideal burning conditions (dried wood, under- and overload, small logs, logs with bark, excess air) were used. We tested 11 hardwood species (apple, ash, bangkirai, birch, beech, cherry, hickory, oak, olive, plum, sugar maple), 4 softwood species (Douglas fir, pine, spruce, spruce/fir), treated softwood, beech and oak wood briquettes, paper briquettes, brown coal, wood chips, and herbaceous species (miscanthus, Chinese silver grass) as fuel. Particle composition (black carbon, non-refractory, and some semi-refractory species) was measured continuously. Repeatability was shown to be better for the pellet stove than for the wood stove. It was shown that the user has a strong influence on wood stove emission behavior both by selection of the fuel and of the burning conditions: Combustion efficiency was found to be low at both very low and very high burn rates, and influenced particle properties such as particle number, mass, and organic content in a complex way. No marked differences were found for the emissions from different wood species. For non-woody fuels, much higher emission factors could be observed (up to five-fold increase). Strongest enhancement of emission factors was found for burning of small or dried logs (up to six-fold), and usage of excess air (two- to three-fold). Real world pellet stove emissions can be expected to be much closer to laboratory-derived emission factors than wood stove emissions, due to lower dependence on user operation.

  6. Mass transfer in fuel cells

    Science.gov (United States)

    Walker, R. D., Jr.

    1973-01-01

    Developments in the following areas are reported: surface area and pore size distribution in electrolyte matrices, electron microscopy of electrolyte matrices, surface tension of KOH solutions, water transport in fuel cells, and effectiveness factors for fuel cell components.

  7. Low noise road surfaces

    OpenAIRE

    Bolčina, Matjaž

    2014-01-01

    Noise is everywhere. Noise is a sound that makes people stressful and irritate. It often couses sleep disorders and also health problems like different cardiovascular disorders, hearing loss…In most cases traffic noise is the most disturbing. There are different ways to prevent people from traffic noise like building noise barriers and insulation of facades. However noise barriers and insulation of facades do not prevent noise formation, but are lowering existing noise. Another disadvantage i...

  8. Shot noise suppression in avalanche photodiodes.

    Science.gov (United States)

    Ma, Feng; Wang, Shuling; Campbell, Joe C

    2005-10-21

    We identify a new shot noise suppression mechanism in a thin (approximately 100 nm) heterostructure avalanche photodiode. In the low-gain regime the shot noise is suppressed due to temporal correlations within amplified current pulses. We demonstrate in a Monte Carlo simulation that the effective excess noise factors can be < 1, and reconcile the apparent conflict between theory and experiments. This shot noise suppression mechanism is independent of known mechanisms such as Coulomb interaction, or reflection at heterojunction interfaces.

  9. Acceptable noise level as a deciding factor for prescribing hearing aids for older adults with cochlear hearing loss e A scoping review

    Institute of Scientific and Technical Information of China (English)

    Hemanth Narayan Shetty; Swathi Subbanna

    2015-01-01

    Older adults often find it difficult to perceive speech, especially in noisy conditions. Though hearing aid is one of the rehabilitative devices available to older adults to alleviate hearing loss, some of them may experience annoyance through hearing aid and hence reject it, may be due to circuitry noise and/or background noise. Acceptable noise level is a direct behavioural measure to estimate the extent of how much a person is able to put up with noise while simultaneously listening to speech. Acceptable noise level is a central auditory measure and it is not influenced by age, gender, presentation level or speaker. Using this measure, we can quantify the annoyance level experienced by an individual. This in-formation is of utmost importance and caution should be paid before setting the parameters in hearing aid, especially for those who are unable to accept noise. In this review article, an attempt has been made to document how to optimize the hearing aid program by setting parameters such as noise reduction circuit, microphone sensitivity and gain. These adjustments of parameters might help to reduce rejection rate of hearing aids, especially in those individuals who are annoyed by background noise. Copyright © 2015 The Authors. Production & hosting by Elsevier (Singapore) Pte Ltd On behalf of PLA General Hospital Department of Otolaryngology Head and Neck Surgery. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  10. Road-Traffic Noise: Annoyance, Risk Perception, and Noise Sensitivity in the Finnish Adult Population

    Science.gov (United States)

    Okokon, Enembe Oku; Turunen, Anu W.; Ung-Lanki, Sari; Vartiainen, Anna-Kaisa; Tiittanen, Pekka; Lanki, Timo

    2015-01-01

    Exposure to road-traffic noise commonly engenders annoyance, the extent of which is determined by factors not fully understood. Our aim was to estimate the prevalence and determinants of road-traffic noise annoyance and noise sensitivity in the Finnish adult population, while comparing the perceptions of road-traffic noise to exhausts as environmental health problems. Using a questionnaire that yielded responses from 1112 randomly selected adult Finnish respondents, we estimated road-traffic noise- and exhausts-related perceived exposures, health-risk perceptions, and self-reported annoyance on five-point scales, while noise sensitivity estimates were based on four questions. Determinants of noise annoyance and sensitivity were investigated using multivariate binary logistic regression and linear regression models, respectively. High or extreme noise annoyance was reported by 17% of respondents. Noise sensitivity scores approximated a Gaussian distribution. Road-traffic noise and exhausts were, respectively, considered high or extreme population-health risks by 22% and 27% of respondents. Knowledge of health risks from traffic noise, OR: 2.04 (1.09–3.82) and noise sensitivity, OR: 1.07 (1.00–1.14) were positively associated with annoyance. Knowledge of health risks (p traffic noise, and perceive it to be a significant health risk, almost comparable to traffic exhausts. There is no distinct noise-sensitive population subgroup. Knowledge of health risks of road-traffic noise, and attitudinal variables are associated with noise annoyance and sensitivity. PMID:26016432

  11. Aircraft, road and railway traffic noise as risk factors for heart failure and hypertensive heart disease-A case-control study based on secondary data.

    Science.gov (United States)

    Seidler, Andreas; Wagner, Mandy; Schubert, Melanie; Dröge, Patrik; Römer, Karin; Pons-Kühnemann, Jörn; Swart, Enno; Zeeb, Hajo; Hegewald, Janice

    2016-11-01

    Several studies point to an elevated risk for cardiovascular diseases induced by traffic noise. We examined the association between aircraft, road traffic and railway noise and heart failure or hypertensive heart disease (HHD) in a large case-control study. The study population consisted of individuals that were insured by three large statutory health insurance funds in the Rhine-Main area of Germany. Based on insurance claims and prescription data, 104,145 cases of heart failure or HHD diagnosed 2006-10 were identified and compared with 654,172 control subjects. Address-specific exposure to aircraft, road and railway traffic noise in 2005 was estimated. Odds Ratios were calculated using logistic regression analysis, adjusted for age, sex, local proportion of persons receiving unemployment benefits, and individual socioeconomic status (available for 39% of the individuals). A statistically significant linear exposure-risk relationship with heart failure or hypertensive heart disease was found for aircraft traffic noise (1.6% risk increase per 10dB increase in the 24-h continuous noise level; 95% CI 0.3-3.0%), road traffic noise (2.4% per 10dB; 95% CI 1.6-3.2%), and railway noise (3.1% per 10dB; 95% CI 2.2-4.1%). For individuals with 24-h continuous aircraft noise levels aircraft noise levels exceeding 50dB six or more times, a significantly increased risk was observed. In general, risks of HHD were considerably higher than the risks of heart failure. Regarding the high prevalence of traffic noise from various sources, even low risk increases for frequent diseases are relevant for the population as a whole. Copyright © 2016 Elsevier GmbH. All rights reserved.

  12. Study on noise of precision panel saw

    Institute of Scientific and Technical Information of China (English)

    HUWan-yi; QIYing-jie; ZHANGZhao-hao; QIXiao-jie

    2003-01-01

    According to ZBJ65015-89 standard about noise level testing method of woodworking toot, the noise testing for MJg0# and MJCl125 precision panel saws was conducted by using model ND2 precision soundqevel apparatus and double frequency wave filter. The testing results showed that the unloaded running noise source of precision panel saw was mainly from main saw blade and its aeromechanic noise was the largest. The rotating speed was determined as an important factor to impact dynamic characters of precision panel saw as the unloaded running noise increased along with speed increasing. For reducing noise of precision panel saw, the first important way is to reduce the aeromechanic noise produced by main saw blade rotating at high speed; based on assuring the processing precision, choosing tow speed is a better way to drop dawn noise; from the view of design, the diameter of clamping lid is better of half of outer diameter of main saw blade.

  13. Experimental studies of factors influencing the self-ignition of gaseous and liquid fuel free jets; Experimentelle Untersuchungen von Einflussfaktoren auf die Selbstzuendung von gasfoermigen und fluessigen Brennstofffreistrahlen

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, Christian

    2010-07-01

    In the present work, the investigation of influencing factors on the auto-ignition of gaseous and liquid free fuel jets are presented. The fuel dimethyl ether (DME) is injected into a high pressure/high temperature atmosphere. The temperature of up to 770 K and pressure of 40 bar enable auto-ignition of the transient free fuel jet during the inflow. To study the influences on the auto-ignition of the gaseous free jet, an extended autoignition probability is established. It includes the time and space resolved auto-ignition probability concerning the ignition limit of the fuel/air-mixture. This state of the autoignition probability is expanded by the auto-ignition probability concerning the local mixture temperature. To gain information of the local temperature, the molar mixture is applied as database. Therefrom the adiabatic local temperature is calculated. To determine a limiting temperature, above which auto-ignition of the local mixture is feasible, a numerical study with the software package HOMREA is performed. Additionally the influence of the flow field on the auto-ignition probability is investigated. As experimental database the time resolved velocity field of the instationary fuel jet is applied and the local strain rate is obtained. To define a critical strain rate, above which an auto-ignition is not possible, a numerical simulation with INSFLA is performed. A coupling of these three single ignition probabilities yield an extended auto-ignition probability. It reveals an abrupt rise in the local ignition probability over a large spatial extend. This time and space resolved rise of the calculated ignition probability shows an excellent agreement with high-speed video sequences of the auto-ignition of the free fuel jet and also with studies of the Laser-induced fluorescence (LIF) of formaldehyde. It turns out that the influence of the flow on the auto-ignition under the conditions of the experiment is negligible. To study the characteristics of the

  14. Performance Factors and Sulfur Tolerance of Metal Supported Solid Oxide Fuel Cells with Nanostructured Ni:GDC Infiltrated Anodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Persson, Åsa Helen; Sudireddy, Bhaskar Reddy

    2015-01-01

    ’s commercially available and relevant SOFC fuels such as natural gas and diesel etc. contain trace amounts of sulfur. Thus, tolerance towards sulfur poisoning is desirable. Ceria and gadolinium doped ceria (GDC) have been reported in the literature to have a beneficial effect on the tolerance towards sulfur...

  15. Performance Factors and Sulfur Tolerance of Metal Supported Solid Oxide Fuel Cells with Nanostructured Ni:GDC Infiltrated Anodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Sudireddy, Bhaskar Reddy; Hagen, Anke;

    2015-01-01

    stainless steel (FeCr) and showed excellent performance characteristics at 650ºC with area specific resistances (ASR) of 0.35 Ωcm2 and 0.7 Ωcm2 respectively. The sulfur tolerance testing was performed by addition/removal of 2, 5, and 10 ppm H2S in hydrogen based fuel under galvanostatic operation...

  16. Study on noise of rapeseed oil blends in a single-cylinder diesel engine

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Y.D.; He, Y. [College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310029 (China)

    2006-09-15

    This study was undertaken to obtain the knowledge necessary for reducing noise of mixed oil composed of rapeseed oil and conventional diesel oil and for improving the performance of engine fuelled by the mixture. A S195 (8.8kW) type single-cylinder diesel engine was used to determine the effect of four adjustable working parameters, i.e. intake-valve-closing angle ({alpha}), exhaust-valve-opening angle ({beta}), fuel delivery angle ({theta}) and injection pressure (P, in 10{sup 4}Pa) on noise when an oil mixture of 30% rapeseed oil and 70% diesel oil was used. Single-factor and multi-factor quadratic regressive orthogonal design test method were adopted in the experiments to find the relationship between noise and four adjustable working parameters. Relationship between these parameters and noise was analysed under two typical operating conditions and mathematical equations characterizing the relationship were formulated. The equation of noise from the regressive test under each operating condition was set as the objective function and the ranges for the four adjustable working parameters were the given constraint condition. Models of nonlinear programming were then constructed. Computer-aided optimization of the working parameters for 30:70 rapeseed oil/diesel oil mixed fuel was achieved. Field test verified that the engine (in use) working condition was found to be bad at maladjustment. The optimum working parameters for two working conditions of the engine were used to adjust the four working parameters. Test results showed that optimum adjustment could achieve noise reduction between 2 and 4dB and that the power could be increased by 0.6-1.8kW. The experimental results also provided useful reference material for selection of the most preferable combination of working parameters. (author)

  17. Development of PEM fuel cell technology at international fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, D.J.

    1996-04-01

    The PEM technology has not developed to the level of phosphoric acid fuel cells. Several factors have held the technology development back such as high membrane cost, sensitivity of PEM fuel cells to low level of carbon monoxide impurities, the requirement to maintain full humidification of the cell, and the need to pressurize the fuel cell in order to achieve the performance targets. International Fuel Cells has identified a hydrogen fueled PEM fuel cell concept that leverages recent research advances to overcome major economic and technical obstacles.

  18. Strategies for Railway Noise

    Science.gov (United States)

    Bovey, E. C.

    1996-05-01

    Strategies are much talked about, but frequently lack any substance. The general concepts of strategic planning are discussed and the need for it to have a focus, i.e., a clear objective, are emphasized. A structural approach to strategic plan development is advocated, with a definition of the relevant issues being a prerequisite for success. Strategies, however, must be flexible and constantly reviewed even though the measures of success are often blurred. Railway noise is clearly amenable to strategic planning, but the issues will vary depending on the objectives of the organization. It is evident that railway noise technology, application and development, while important, needs to be substantially supplemented by other factors such as logistics and management issues to form an effective strategy in this domain.

  19. Calculation of thermal noise in grating reflectors

    CERN Document Server

    Heinert, Daniel; Friedrich, Daniel; Hild, Stefan; Kley, Ernst-Bernhard; Leavey, Sean; Martin, Iain W; Nawrodt, Ronny; Tünnermann, Andreas; Vyatchanin, Sergey P; Yamamoto, Kazuhiro

    2013-01-01

    Grating reflectors have been repeatedly discussed to improve the noise performance of metrological applications due to the reduction or absence of any coating material. So far, however, no quantitative estimate on the thermal noise of these reflective structures exists. In this work we present a theoretical calculation of a grating reflector's noise. We further apply it to a proposed 3rd generation gravitational wave detector. Depending on the grating geometry, the grating material and the temperature we obtain a thermal noise decrease by up to a factor of ten compared to conventional dielectric mirrors. Thus the use of grating reflectors can substantially improve the noise performance in metrological applications.

  20. Spin-noise correlations and spin-noise exchange driven by low-field spin-exchange collisions

    OpenAIRE

    Dellis, A. T.; Loulakis, M.; Kominis, I. K.

    2013-01-01

    The physics of spin exchange collisions have fueled several discoveries in fundamental physics and numerous applications in medical imaging and nuclear magnetic resonance. We here report on the experimental observation and theoretical justification of spin-noise exchange, the transfer of spin-noise from one atomic species to another. The signature of spin-noise exchange is an increase of the total spin-noise power at low magnetic fields, on the order of 1 mG, where the two-species spin-noise ...

  1. Inhibitory noise

    Directory of Open Access Journals (Sweden)

    Alain Destexhe

    2010-03-01

    Full Text Available Cortical neurons in vivo may operate in high-conductance states, in which the major part of the neuron's input conductance is due to synaptic activity, sometimes several-fold larger than the resting conductance. We examine here the contribution of inhibition in such high-conductance states. At the level of the absolute conductance values, several studies have shown that cortical neurons in vivo are characterized by strong inhibitory conductances. However, conductances are balanced and spiking activity is mostly determined by fluctuations, but not much is known about excitatory and inhibitory contributions to these fluctuations. Models and dynamic-clamp experiments show that, during high-conductance states, spikes are mainly determined by fluctuations of inhibition, or by inhibitory noise. This stands in contrast to low-conductance states, in which excitatory conductances determine spiking activity. To determine these contributions from experimental data, maximum likelihood methods can be designed and applied to intracellular recordings in vivo. Such methods indicate that action potentials are indeed mostly correlated with inhibitory fluctuations in awake animals. These results argue for a determinant role for inhibitory fluctuations in evoking spikes, and do not support feed-forward modes of processing, for which opposite patterns are predicted.

  2. Noise Pollution Prevention in Wind Turbines: Status and Recent Advances

    Directory of Open Access Journals (Sweden)

    Greg Naterer

    2012-05-01

    Full Text Available The global push towards sustainability has led to increased interest in alternative power sources other than coal and fossil fuels. One of these sustainable sources is to harness energy from the wind through wind turbines. However, a significant hindrance preventing the widespread use of wind turbines is the noise they produce. This study reviews recent advances in the area of noise pollution from wind turbines. To date, there have been many different noise control studies. While there are many different sources of noise, the main one is aerodynamic noise. The largest contributor to aerodynamic noise comes from the trailing edge of wind turbine blades. The aim of this paper is to critically analyse and compare the different methods currently being implemented and investigated to reduce noise production from wind turbines, with a focus on the noise generated from the trailing edge.

  3. Generation of indirect combustion noise by compositional inhomogeneities

    Science.gov (United States)

    Magri, Luca; O'Brien, Jeff; Ihme, Matthias

    2016-11-01

    The generation of indirect combustion noise in nozzles and turbine stages is commonly attributed to temperature inhomogeneities and vorticity fluctuations. Here, compositional inhomogeneities in a multi-component gas mixture are shown to produce indirect noise both theoretically and numerically. The chemical potential function is introduced as an additional acoustic source mechanism. The contribution of the compositional noise is compared to the entropy noise and direct noise by considering subsonic, supersonic and shocked nozzles downstream of the combustor exit. It is shown that the compositional noise is dependent on the local mixture composition and can exceed entropy noise for fuel-lean conditions and supersonic/shocked nozzle flows. This suggests that compositional indirect combustion noise may require consideration with the implementation of advanced combustion concepts in gas turbines, including low-emissions combustors, high-power-density engine cores, or compact burners.

  4. Recycling of ash - an important factor in the forest fuel cycle; Askaaterfoering - en viktig faktor i skogsbraenslets kretslopp

    Energy Technology Data Exchange (ETDEWEB)

    Lundborg, A.

    1997-12-31

    If energy sources are to be called renewable, they must be used on the conditions set by nature and natural balance must be maintained. The ash from biofuels from forests contains almost all the minerals and nutrients (except nitrogen) which were present in the fuel and should be recycled to the forest. This conference paper describes the composition and properties of ash, its production and handling, and its ecological effects when recycled. The chemical properties of ash depend largely on the content of minerals, nutrients and heavy metals in the fuel, and on how the combustion process is conducted. Ash from bioforests or from waste combustion may contain heavy metals and may be unsuitable for recycling. Ash is strongly alkaline and needs processing before recycling. In forests that grow on peat the addition of ash causes a strong growth of trees. On firm ground, however, the effect of adding ash is more in the nature of long-time forest care. 4 refs.

  5. Noise in eukaryotic gene expression

    Science.gov (United States)

    Blake, William J.; KÆrn, Mads; Cantor, Charles R.; Collins, J. J.

    2003-04-01

    Transcription in eukaryotic cells has been described as quantal, with pulses of messenger RNA produced in a probabilistic manner. This description reflects the inherently stochastic nature of gene expression, known to be a major factor in the heterogeneous response of individual cells within a clonal population to an inducing stimulus. Here we show in Saccharomyces cerevisiae that stochasticity (noise) arising from transcription contributes significantly to the level of heterogeneity within a eukaryotic clonal population, in contrast to observations in prokaryotes, and that such noise can be modulated at the translational level. We use a stochastic model of transcription initiation specific to eukaryotes to show that pulsatile mRNA production, through reinitiation, is crucial for the dependence of noise on transcriptional efficiency, highlighting a key difference between eukaryotic and prokaryotic sources of noise. Furthermore, we explore the propagation of noise in a gene cascade network and demonstrate experimentally that increased noise in the transcription of a regulatory protein leads to increased cell-cell variability in the target gene output, resulting in prolonged bistable expression states. This result has implications for the role of noise in phenotypic variation and cellular differentiation.

  6. Occupational noise management

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-06-15

    Occupational noise is a frequently encountered on-the-job health hazard. This guide presented the responsibilities and regulatory requirements related to business activities where noise above 80 decibels is present. The guide provided a definition of noise and discussed noise hazards, types of noise, and on-the-job noise exposure. A risk assessment to noise in the work environment was also discussed. A guide to a hearing conservation program was also included. The main purpose of a hearing conservation program is the prevention of noise induced hearing loss for employees exposed to occupational noise. The components of such a program were outlined, with particular reference to noise monitoring; noise exposure control; worker education and training; hearing (audiometric) testing; and annual program review and record keeping. It was concluded that in terms of record keeping, it can be very helpful to file noise exposure assessments, particularly personal exposure measurements, with hearing test records to facilitate for future reference. refs., appendices.

  7. Noise and Hearing Protection

    Science.gov (United States)

    ... ENTCareers Marketplace Find an ENT Doctor Near You Noise and Hearing Protection Noise and Hearing Protection Patient ... it is. How can I tell if a noise is dangerous? People differ in their sensitivity to ...

  8. The Procedure for Determination of Special Margin Factors to Account for a Bow of the VVER-1000 Fuel Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Tsyganov, Sergey V.; Marin, Stanislav V.; Shishkov, Lev K. [Russian Research Center ' Kurchatov Institute' , 1., Kurchatov sq., 123182 Moscow (Russian Federation)

    2008-07-01

    Starting from 1980's, the problem of bow of the VVER-1000 reactor FAs and the effect of that on the operational safety is being discussed. At the initial period of time, the extension of time for dropping control rods of the control and protection system associated with this bow posed the highest threat. Later on, new more rigid structures were developed for FAs that eliminated the problems of control rods. However, bow of the VVER-1000 reactor FAs is observed up to now. The scale of this bow reduced significantly but it still effects safety. Even a minor bow available may lead to the noticeable increase of power of individual fuel pins associated with the local variation of the coolant amount. This effect must be taken into account on designing fuel loadings to eliminate the exceeding of set limitations. The introduction of additional special margins is the standard method for taking this effect into account. The present paper describes the conservative technique for the assessment of additional margins for bow of FAs of state-of-the-art designs. This technique is employed in the VVER-1000 reactor designing. The chosen conservatism degree is discussed as well as the method for its assurance and acceptable ways for its slackening. The example of the margin evaluation for the up-to-date fuel loading is given. (authors)

  9. Evaluation of the effects of exposure to organic solvents and hazardous noise among US Air Force Reserve personnel

    Directory of Open Access Journals (Sweden)

    Hayley Hughes

    2013-01-01

    Full Text Available Hearing loss affects many workers including those in the military and may be caused by noise, medications, and chemicals. Exposures to some chemicals may lead to an increase in the incidence of hearing loss when combined with hazardous noise. This retrospective study evaluated the risk for hearing loss among Air Force Reserve personnel exposed to occupational noise with and without exposures to toluene, styrene, xylene, benzene, and JP-8 (jet fuel. Risk factors associated with hearing loss were determined using logistic and linear regression. Stratified analysis was used to evaluate potential interaction between solvent and noise exposure. The majority of the subjects were male (94.6% and 35 years or older on the date of their first study audiogram (66%. Followed for an average of 3.2 years, 9.2% of the study subjects had hearing loss in at least one ear. Increasing age (odds ratio [OR] = 1.03 per year of age and each year of follow-up time (OR = 1.23 were significantly associated with hearing loss. Low and moderate solvent exposures were not associated with hearing loss. Linear regression demonstrated that hearing loss was significantly associated with age at first study audiogram, length of follow-up time, and exposure to noise. Hearing decreased by 0.04 decibels for every decibel increase in noise level or by almost half a decibel (0.4 dB for every 10 decibel increase in noise level.

  10. Long-term exposure to road traffic noise, ambient air pollution, and cardiovascular risk factors in the HUNT and lifelines cohorts.

    Science.gov (United States)

    Cai, Yutong; Hansell, Anna L; Blangiardo, Marta; Burton, Paul R; de Hoogh, Kees; Doiron, Dany; Fortier, Isabel; Gulliver, John; Hveem, Kristian; Mbatchou, Stéphane; Morley, David W; Stolk, Ronald P; Zijlema, Wilma L; Elliott, Paul; Hodgson, Susan

    2017-08-01

    Blood biochemistry may provide information on associations between road traffic noise, air pollution, and cardiovascular disease risk. We evaluated this in two large European cohorts (HUNT3, Lifelines). Road traffic noise exposure was modelled for 2009 using a simplified version of the Common Noise Assessment Methods in Europe (CNOSSOS-EU). Annual ambient air pollution (PM10, NO2) at residence was estimated for 2007 using a Land Use Regression model. The statistical platform DataSHIELD was used to pool data from 144 082 participants aged ≥20 years to enable individual-level analysis. Generalized linear models were fitted to assess cross-sectional associations between pollutants and high-sensitivity C-reactive protein (hsCRP), blood lipids and for (Lifelines only) fasting blood glucose, for samples taken during recruitment in 2006-2013. Pooling both cohorts, an inter-quartile range (IQR) higher day-time noise (5.1 dB(A)) was associated with 1.1% [95% confidence interval (95% CI: 0.02-2.2%)] higher hsCRP, 0.7% (95% CI: 0.3-1.1%) higher triglycerides, and 0.5% (95% CI: 0.3-0.7%) higher high-density lipoprotein (HDL); only the association with HDL was robust to adjustment for air pollution. An IQR higher PM10 (2.0 µg/m3) or NO2 (7.4 µg/m3) was associated with higher triglycerides (1.9%, 95% CI: 1.5-2.4% and 2.2%, 95% CI: 1.6-2.7%), independent of adjustment for noise. Additionally for NO2, a significant association with hsCRP (1.9%, 95% CI: 0.5-3.3%) was seen. In Lifelines, an IQR higher noise (4.2 dB(A)) and PM10 (2.4 µg/m3) was associated with 0.2% (95% CI: 0.1-0.3%) and 0.6% (95% CI: 0.4-0.7%) higher fasting glucose respectively, with both remaining robust to adjustment for air/noise pollution. Long-term exposures to road traffic noise and ambient air pollution were associated with blood biochemistry, providing a possible link between road traffic noise/air pollution and cardio-metabolic disease risk.

  11. Assessment of Traffic Noise Impacts

    DEFF Research Database (Denmark)

    Rich, Jeppe Husted; Nielsen, Otto Anker

    2004-01-01

    A steady growth in traffic intensities in most urban areas throughout the world has forced planners and politicians to seriously consider the resulting environmental impact, such as traffic noise, accidents and air pollution. The assessment of such negative factors is needed in order to reveal...... the true social benefit of infrastructure plans. The paper presents a noise assessment model for the Copenhagen region, which brings together GIS technology and non-linear hedonic regression models to reveal the implicit costs of traffic noise measured as the marginal percentage loss in property values...... with respect to the decibel traffic noise. The model distinguishes between houses and apartments and shows that the ability to include refined accessibility variables have significant impact on estimated prices....

  12. Fuel assembly reconstitution

    Energy Technology Data Exchange (ETDEWEB)

    Morgado, Mario M.; Oliveira, Monica G.N.; Ferreira Junior, Decio B.M.; Santos, Barbara O. dos; Santos, Jorge E. dos, E-mail: mongeor@eletronuclear.gov.b [ELETROBRAS Termonuclear S.A. - ELETRONUCLEAR, Angra dos Reis, RJ (Brazil)

    2009-07-01

    Fuel failures have been happened in Nuclear Power Plants worldwide, without lost of integrity and safety, mainly for the public, environment and power plants workers. The most common causes of these events are corrosion (CRUD), fretting and pellet cladding interaction. These failures are identified by increasing the activity of fission products, verified by chemical analyses of reactor coolant. Through these analyses, during the fourth operation cycle of Angra 2 Nuclear Power Plant, was possible to observe fuel failure indication. This indication was confirmed in the end of the cycle during the unloading of reactor core through leakage tests of fuel assembly, using the equipment called 'In Mast Sipping' and 'Box Sipping'. After confirmed, the fuel assembly reconstitution was scheduled, and happened in April, 2007, where was identified the cause and the fuel rod failure, which was substitute by dummy rods (zircaloy). The cause was fretting by 'debris'. The actions to avoid and prevent fuel assemblies failures are important. The goals of this work are to describe the methodology of fuel assembly reconstitution using the FARE (Fuel Assembly Reconstitution Equipment) system, to describe the results of this task in economic and security factors of the company and show how the fuel assembly failures are identified during operation and during the outage. (author)

  13. Prediction of the local power factor in BWR fuel cells by means of a multilayer neural network; Prediccion del factor local de potencia en celdas de combustible BWR mediante una red neuronal multicapas

    Energy Technology Data Exchange (ETDEWEB)

    Montes, J.L.; Ortiz, J.J.; Perusquia C, R. [ININ, Carretera Mexico-Toluca s/n, 52750 La Marquesa, Ocoyoacac, Estado de Mexico (Mexico); Francois, J.L.; Martin del Campo M, C. [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Morelos (Mexico)]. e-mail: jlmt@nuclear.inin.mx

    2007-07-01

    To the beginning of a new operation cycle in a BWR reactor the reactivity of this it increases by means of the introduction of fresh fuel, the one denominated reload fuel. The problem of the definition of the characteristics of this reload fuel represents a combinatory optimization problem that requires significantly a great quantity of CPU time for their determination. This situation has motivated to study the possibility to substitute the Helios code, the one which is used to generate the new cells of the reload fuel parameters, by an artificial neuronal network, with the purpose of predicting the parameters of the fuel reload cell of a BWR reactor. In this work the results of the one training of a multilayer neuronal net that can predict the local power factor (LPPF) in such fuel cells are presented. The prediction of the LPPF is carried out in those condition of beginning of the life of the cell (0.0 MWD/T, to 40% of holes in the one moderator, temperature of 793 K in the fuel and a moderator temperature of 560 K. The cells considered in the present study consist of an arrangement of 10x10 bars, of those which 92 contains U{sup 235}, some of these bars also contain a concentration of Gd{sub 2}O{sub 3} and 8 of them contain only water. The axial location inside the one assembles of recharge of these cells it is exactly up of the cells that contain natural uranium in the base of the reactor core. The training of the neuronal net is carried out by means of a retro-propagation algorithm that uses a space of training formed starting from previous evaluations of cells by means of the Helios code. They are also presented the results of the application of the neuronal net found for the prediction of the LPPF of some cells used in the real operation of the Unit One of the Laguna Verde Nuclear Power station. (Author)

  14. 基于非负矩阵分解的机场噪声监测点优化布局%Optimal Locating Method for the Layout of Airport Noise Monitoring Sites Based on Non-negative Matrix Factorization

    Institute of Scientific and Technical Information of China (English)

    李永华; 唐先超

    2014-01-01

    近年来国内民航迅速发展,机场的新建、扩建和航空运输量的持续增长使得机场噪声污染事件不仅持续上升,而且噪声污染程度也日益加重,因而强化机场附近噪声污染的监测对机场建设及其环境评估十分重要。针对机场噪声污染监测问题,提出一种基于非负矩阵分解(NMF)方法对机场噪声监测点布局问题进行优化求解。该方法以大量网格点作为候选监测点,对单个飞机噪声事件候选监测点的噪声值所形成的矩阵按非负矩阵分解进行区域划分,得到噪声影响子区域。进一步以各子区域的中心点作为该区域的噪声影响代表点,以此确定机场噪声监测点数目和位置。研究结果表明所获得的解比贪心算法得到的解更优,需要的监测点更少。%With the rapid development of domestic civil aviation in recent years, noise pollution of airports is becoming a serious problem. Thus, strengthening the noise monitoring in the airport vicinity is very important for airport construction and environmental evaluation. Aiming at the monitoring of airport noise pollution, an optimization method based on non-negative matrix factorization (NMF) is put forward to optimize the layout of the noise monitoring sites. In this method, large number of the grid nodes is employed as the candidate monitoring points, and the non-negative matrix composed of the noise values from single flight event at the candidate monitoring points is formed. Then, the non-negative matrix is factorized to obtain the effective subdivision of noise. Furthermore, the location and number of the noise monitoring sites are determined by the representative central point of the effective subdivisions. It is shown that this method needs fewer monitoring locating sites and can get better results than the greedy algorithm.

  15. Quantum limited heterodyne detection of spin noise

    Science.gov (United States)

    Cronenberger, S.; Scalbert, D.

    2016-09-01

    Spin noise spectroscopy is a powerful technique for studying spin relaxation in semiconductors. In this article, we propose an extension of this technique based on optical heterodyne detection of spin noise, which provides several key advantages compared to conventional spin noise spectroscopy: detection of high frequency spin noise not limited by detector bandwidth or sampling rates of digitizers, quantum limited sensitivity even in case of very weak probe power, and possible amplification of the spin noise signal. Heterodyne detection of spin noise is demonstrated on insulating n-doped GaAs. From measurements of spin noise spectra up to 0.4 Tesla, we determined the distribution of g-factors, Δg/g = 0.49%.

  16. Influence of fuel mass load, oxygen supply and burning rate on emission factor and size distribution of carbonaceous particulate matter from indoor corn straw burning

    Institute of Scientific and Technical Information of China (English)

    Guofeng Shen; Miao Xue; Siye Wei; Yuanchen Chen; Bin Wang; Rong Wang; Huizhong Shen

    2013-01-01

    The uncertainty in emission estimation is strongly associated with the variation in emission factor (EF),which could be influenced bya variety of factors such as fuel properties,stove type,fire management and even methods used in measurements.The impacts of thesefactors are complicated and often interact with each other.Controlled burning experiments were conducted to investigate the influencesof fuel mass load,air supply and burning rate on the emissions and size distributions of carbonaceous particulate matter (PM) fromindoor corn straw bunting in a cooking stove.The results showed that the EFs of PM (EFpM),organic carbon (EFoc) and elementalcarbon (EFEc) were independent of the fuel mass load.The differences among them under different burning rates or air supply amountswere also found to be insignificant (P > 0.05) in the tested circumstances.PM from the indoor corn straw burning was dominated byfine PM with diameter less than 2.1 μm,contributing 86.4% ± 3.9% of the total.The size distribution of PM was influenced by theburning rate and air supply conditions.On average,EFPM,EFoc and EFEC for corn straw burned in a residential cooking stove were(3.84 ± 1.02),(0.846 ± 0.895) and (0.391 ± 0.350) g/kg,respectively.EFPM,EFoc and EFEc were found to be positively correlatedwith each other (P < 0.05),but they were not significantly correlated with the EF of co-emitted CO,suggesting that special attentionshould be paid to the use of CO as a surrogate for other incomplete combustion pollutants.

  17. Development of multi-dimensional thermal hydraulic modeling using mixing factors for wire wrapped fuel pin bundles with inter-subassembly heat transfer in fast reactors

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, M.; Kamide, H.; Ohshima, H. [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1996-10-01

    Temperature distributions in fuel subassemblies of fast reactors interactively affect heat transfer from center to outer region of the core (inter-subassembly heat transfer) and cooling capability of an inter-wrapper flow, as well as maximum cladding temperature. The prediction of temperature distribution in the sub-assembly is, therefore one of the important issues for the reactor safety assessment. To treat the complex phenomena in the core, a multi-dimensional thermal hydraulic analysis is the most promising method. From the studies on the multi-dimensional thermal hydraulic modeling for the fuel sub-assemblies, the modeling have been recommended through the analysis of sodium experiments using driver subassembly test rig PLANDTL-DHX and blanket subassembly test rig CCTL-CFR. Computations of steady states experiments in the test rigs using the above modeling showed quite good agreement to the experimental data. In the present study, the use of this modeling was extended to transient analyses, and its applicability was examined. Firstly, non-dimensional parameters used to determine the mixing factors were modified from the ones based on bundle-averaged values to the ones by local values. Secondly, a new threshold function was derived and introduced to cut off the mixing factor of thermal plumes under inertia force dominant conditions. In the results of this validation, the accuracy was comparable between the modeling and the experimental instrumentation. Thus the present modeling is capable of predicting the thermal hydraulic fields of the wire wrapped fuel pin bundles with inter-subassembly heat transfer under the conditions from rated steady operations to transitions toward natural circulation decay heat removal modes. (J.P.N.)

  18. Dimethyl Ether as a Fuel for Diesel Engines

    DEFF Research Database (Denmark)

    Sorenson, Spencer C.

    1999-01-01

    DME has recently been shown to be an attractive high cetane fuel for diesel engines, offering the advantages of soot free operation, with low engine noise, the potential for low NOx emissions, and low reactivity emissions of hydrocarbons and unburned fuel. DME has physical characteristics similar...... of engine fuels systems in regard to lubricity and suitable sealing materials....

  19. Research on Influence Factors of Fuel Combustion in Oxy-fuel Boilers%富氧燃烧条件下锅炉燃料燃烧影响因素研究

    Institute of Scientific and Technical Information of China (English)

    杨铭; 王春华; 王志华; 赵占明; 李文兴; 姜冠佳

    2015-01-01

    Based on the calculation method of fuel combustion in boiler under the condition of the oxygen-enriched combustion, combining with the characteristics of oxygen-enriched boiler thermodynamic system, the fuel combustion calculation software was developed using Visual Basic 6.0. By the software, the influence of the oxygen concentration on the boiler efficiency, combustion air volume and smoke gas volume was analyzed as well as the impact of discharge smoke temperature, excess oxygen coefficient on the boiler thermal efficiency. The results show that theoretical air volume and smoke volume decrease with the increase of oxygen concentration; the boiler thermal efficiency rises with the increase of oxygen concentration and reduction of excess oxygen coefficient; the higher the smoke temperature, the slower the boiler thermal efficiency rising rate; under lower oxygen concentration, the oxygen concentration has significant influence on the combustion air volume, smoke volume, boiler thermal efficiency and fuel consumption; on the other hand, under higher oxygen concentration, oxygen concentration has relatively less influence on the above mentioned factors.%以他人建立的富氧燃烧条件下锅炉燃料燃烧计算为框架,结合富氧锅炉热力系统的特点,运用Visual Basic 6.0开发了富氧燃烧条件下燃料燃烧计算软件,分析了锅炉操作参数中氧气浓度对锅炉效率、空气量、烟气量的影响;分析了富氧燃烧条件下排烟温度、过量氧气系数对锅炉热效率的影响。结果显示:理论空气量和理论干烟气量随着氧气浓度的增加而减少;锅炉热效率随着氧气浓度的增加和过量氧气系数的减小呈上升趋势,而且排烟温度越高,锅炉热效率上升越慢;低氧气浓度下,氧气浓度的变化对锅炉燃烧用空气量、烟气量、锅炉热效率、燃料消耗量的影响较为显著;高氧气浓度下,影响相对减弱。

  20. Longitudinal Study of Human Hearings: Its Relationship to Noise and Other Factors. 1. Design of Five Year Study; Data from First Year

    Science.gov (United States)

    1977-03-01

    that exposure to loud noises causes more histological damage in young than in adult guinea pigs (Jauhiainen et al., 1972) and that kittens lose more...particular care . Further, serial studies offer several advantages over cross-sectional studies. The major reasons why serial studies of auditory

  1. Occupational noise, smoking, and a high body mass index are risk factors for age-related hearing impairment and moderate alcohol consumption is protective: A European population-based multicenter study

    DEFF Research Database (Denmark)

    Fransen, E.; Topsakal, V.; Hendrickx, J.J.

    2008-01-01

    exposure was associated with a significant loss of hearing at high sound frequencies (> 1 kHz). Smoking significantly increased high-frequency hearing loss, and the effect was dose-dependent. The effect of smoking remained significant when accounting for cardiovascular disease events. Taller people had......-tone average [PTA]) were collected and the participants filled out a questionnaire on environmental risk factors and medical history. People with a history of disease that could affect hearing were excluded. PTAs were adjusted for age and sex and tested for association with exposure to risk factors. Noise...

  2. Can Noise Kill People?

    Institute of Scientific and Technical Information of China (English)

    刘玲娣

    2007-01-01

    Someone is singing next door,but you feel unhappy because her singing is just making a noise.We know that too much noise makes people feel terrible. Scientists are still trying to find out more about noise,but already it is known that a noise of over 85 decibels can make some people tired and anxious.

  3. Aircraft propeller induced structure-borne noise

    Science.gov (United States)

    Unruh, James F.

    1989-01-01

    A laboratory-based test apparatus employing components typical of aircraft construction was developed that would allow the study of structure-borne noise transmission due to propeller induced wake/vortex excitation of in-wake structural appendages. The test apparatus was employed to evaluate several aircraft installation effects (power plant placement, engine/nacelle mass loading, and wing/fuselage attachment methods) and several structural response modifications for structure-borne noise control (the use of wing blocking mass/fuel, wing damping treaments, and tuned mechanical dampers). Most important was the development of in-flight structure-borne noise transmission detection techniques using a combination of ground-based frequency response function testing and in-flight structural response measurement. Propeller wake/vortex excitation simulation techniques for improved ground-based testing were also developed to support the in-flight structure-borne noise transmission detection development.

  4. Active Noise Control for Dishwasher noise

    Science.gov (United States)

    Lee, Nokhaeng; Park, Youngjin

    2016-09-01

    The dishwasher is a useful home appliance and continually used for automatically washing dishes. It's commonly placed in the kitchen with built-in style for practicality and better use of space. In this environment, people are easily exposed to dishwasher noise, so it is an important issue for the consumers, especially for the people living in open and narrow space. Recently, the sound power levels of the noise are about 40 - 50 dBA. It could be achieved by removal of noise sources and passive means of insulating acoustical path. For more reduction, such a quiet mode with the lower speed of cycle has been introduced, but this deteriorates the washing capacity. Under this background, we propose active noise control for dishwasher noise. It is observed that the noise is propagating mainly from the lower part of the front side. Control speakers are placed in the part for the collocation. Observation part of estimating sound field distribution and control part of generating the anti-noise are designed for active noise control. Simulation result shows proposed active noise control scheme could have a potential application for dishwasher noise reduction.

  5. Ranking of Reactions Based on Sensitivity of Protein Noise Depends on the Choice of Noise Measure.

    Directory of Open Access Journals (Sweden)

    Sucheta Gokhale

    Full Text Available Gene expression is a stochastic process. Identification of the step maximally affecting noise in the protein level is an important aspect of investigation of gene product distribution. There are numerous experimental and theoretical studies that seek to identify this important step. However, these studies have used two different measures of noise, viz. coefficient of variation and Fano factor, and have compared different processes leading to contradictory observations regarding the important step. In this study, we performed systematic global and local sensitivity analysis on two models of gene expression to investigate relative contribution of reaction rate parameters to steady state noise in the protein level using both the measures of noise. We analytically and computationally showed that the ranking of parameters based on the sensitivity of the noise to variation in a given parameter is a strong function of the choice of the noise measure. If the Fano factor is used as the noise measure, translation is the important step whereas for coefficient of variation, transcription is the important step. We derived an analytical expression for local sensitivity and used it to explain the distinct contributions of each reaction parameter to the two measures of noise. We extended the analysis to a generic linear catalysis reaction system and observed that the reaction network topology was an important factor influencing the local sensitivity of the two measures of noise. Our study suggested that, for the analysis of contributions of reactions to the noise, consideration of both the measures of noise is important.

  6. Fossil Fuels.

    Science.gov (United States)

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with fossil fuels. Some topics covered are historic facts, development of fuels, history of oil production, current and future trends of the oil industry, refining fossil fuels, and environmental problems. Material in each unit may…

  7. Fossil Fuels.

    Science.gov (United States)

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with fossil fuels. Some topics covered are historic facts, development of fuels, history of oil production, current and future trends of the oil industry, refining fossil fuels, and environmental problems. Material in each unit may…

  8. Development of DUPIC fuel cycle technology - Assessment of Wolsong NPP fuel handling system for DUPIC fuel

    Energy Technology Data Exchange (ETDEWEB)

    Na, Bok Gyun; Nam, Gung Ihn [Korea Power Engineering Company, Taejon (Korea)

    2000-04-01

    The DUPIC fuel loading and discharge path of Wolsong NPP is studied assuming that DUPIC fuel is used at Wolsong NPP. Spent DUPIC fuel discharge path is irrelevant, since it uses the same spent fuel discharge path. Number of factors such as safety, economics of design change, radiation exposure to operators, easy of operation and maintenance, etc, are considered in the evaluation of path. A more detailed analysis of cost estimation of the selected path is also carried out. The study shows that DUPIC fuel loading path following through Spent Fuel Storage Bay and Spent Fuel Discharge Port in reverse direction will minimize the design change and additional equipment and radiation exposure to operators. The estimated total cost of using DUPIC fuel in Wolsong NPP based on price index of year 2000 is around 4.5 billion won. 4 refs., 30 figs., 13 tabs. (Author)

  9. Idling - cruising the fuel inefficiency highway.

    Energy Technology Data Exchange (ETDEWEB)

    Gaines, L.; Levinson, T. (Energy Systems); (DOE)

    2011-06-30

    What is the purpose of idling? The scale of idling can be small, as when parents idle their vehicles while waiting for their children outside of school, or it can be large, as when ocean liners are in port. In many cases, the primary purpose for idling is to control the temperature of a passenger or freight compartment. Large line-haul trucks idle overnight to keep fuel and the engine warm, for the resting driver's comfort, to mask out noises and smells, and for safety. In addition, all classes of trucks idle during the workday at ports and terminals, busy delivery sites, border crossings, and other work sites. They may be idling to enable slow movement in a queue (creep idling) or to provide other services. Bus drivers also idle their vehicles while they wait for passengers and to warm up in the morning. Even locomotive engines are idled so they start, for hotel load, to keep the battery charged, to keep the toilet water from freezing, and for air brakes, or because the operator idles out of habit. Although this document focuses on long-haul trucks, much of the information applies to other vehicles as well. The impacts of idling are substantial, with as much as 6 billion gallons of fuel burned unnecessarily each year in the United States at a cost of over $20 billion. The extra hours of engine operation also cost the owners money for more frequent maintenance and overhauls. In addition, idling vehicles emit particulates (PM{sub 10}), nitrogen dioxide (NO{sub 2}), carbon monoxide (CO), and carbon dioxide (CO{sub 2}). These emissions, along with noise from idling vehicles, have led to many local and state restrictions on idling. Two main factors have combined to create a surge of interest in idling reduction (IR): (1) Increasing restrictions on idling for heavy vehicles and (2) The price of diesel fuel. Because stakeholders focus their efforts on improving different factors (air quality, fuel economy, noise level), they do not necessarily agree on the most

  10. An overview of health effects on noise

    Science.gov (United States)

    Osada, Y.

    1988-12-01

    Although noise can damage the inner ear and cause other pathological changes, its most common negative effects are non-somatic, such as a perception of noisiness and disturbance of daily activities. According to the definition of health by WHO, this should be considered as a health hazard. These health effects of noise can be classified into the following three categories: (I) hearing loss, perception of noisiness and masking are produced along the auditory pathway and are thus direct and specific effects of noise; (II) interference with performance, rest and sleep, a feeling of discomfort and some physiological effects are produced as indirect and non-specific effects via reticular formation of the midbrain; (III) annoyance is not merely a feeling of unpleasantness but the feeling of being bothered or troubled, and includes the development of a particular attitude toward the noise source. Individual or group behavioral responses will be evoked when annoyance develops. Annoyance and behavioral response are integrated and composite effects. The health effects of noise are modified by many factors related to both the noise and the individual. Noise level, frequency spectrum, duration and impulsiveness modify the effects. Sex, age, health status and mental character also have an influence on the effects. Direct effects of noise are most dependent on the physical nature of the noise and least dependent on human factors. Indirect effects are more dependent, and integrated effects most dependent, on human factors.

  11. Formant discrimination in noise for isolated vowels

    Science.gov (United States)

    Liu, Chang; Kewley-Port, Diane

    2004-11-01

    Formant discrimination for isolated vowels presented in noise was investigated for normal-hearing listeners. Discrimination thresholds for F1 and F2, for the seven American English vowels /eye, smcapi, eh, æ, invv, aye, you/, were measured under two types of noise, long-term speech-shaped noise (LTSS) and multitalker babble, and also under quiet listening conditions. Signal-to-noise ratios (SNR) varied from -4 to +4 dB in steps of 2 dB. All three factors, formant frequency, signal-to-noise ratio, and noise type, had significant effects on vowel formant discrimination. Significant interactions among the three factors showed that threshold-frequency functions depended on SNR and noise type. The thresholds at the lowest levels of SNR were highly elevated by a factor of about 3 compared to those in quiet. The masking functions (threshold vs SNR) were well described by a negative exponential over F1 and F2 for both LTSS and babble noise. Speech-shaped noise was a slightly more effective masker than multitalker babble, presumably reflecting small benefits (1.5 dB) due to the temporal variation of the babble. .

  12. Road-Traffic Noise: Annoyance, Risk Perception, and Noise Sensitivity in the Finnish Adult Population

    Directory of Open Access Journals (Sweden)

    Enembe Oku Okokon

    2015-05-01

    Full Text Available Exposure to road-traffic noise commonly engenders annoyance, the extent of which is determined by factors not fully understood. Our aim was to estimate the prevalence and determinants of road-traffic noise annoyance and noise sensitivity in the Finnish adult population, while comparing the perceptions of road-traffic noise to exhausts as environmental health problems. Using a questionnaire that yielded responses from 1112 randomly selected adult Finnish respondents, we estimated road-traffic noise- and exhausts-related perceived exposures, health-risk perceptions, and self-reported annoyance on five-point scales, while noise sensitivity estimates were based on four questions. Determinants of noise annoyance and sensitivity were investigated using multivariate binary logistic regression and linear regression models, respectively. High or extreme noise annoyance was reported by 17% of respondents. Noise sensitivity scores approximated a Gaussian distribution. Road-traffic noise and exhausts were, respectively, considered high or extreme population-health risks by 22% and 27% of respondents. Knowledge of health risks from traffic noise, OR: 2.04 (1.09–3.82 and noise sensitivity, OR: 1.07 (1.00–1.14 were positively associated with annoyance. Knowledge of health risks (p < 0.045 and positive environmental attitudes (p < 000 were associated with higher noise sensitivity. Age and sex were associated with annoyance and sensitivity only in bivariate models. A considerable proportion of Finnish adults are highly annoyed by road-traffic noise, and perceive it to be a significant health risk, almost comparable to traffic exhausts. There is no distinct noise-sensitive population subgroup. Knowledge of health risks of road-traffic noise, and attitudinal variables are associated with noise annoyance and sensitivity.

  13. Mechanics of underwater noise

    CERN Document Server

    Ross, Donald

    1976-01-01

    Mechanics of Underwater Noise elucidates the basic mechanisms by which noise is generated, transmitted by structures and radiated into the sea. Organized into 10 chapters, this book begins with a description of noise, decibels and levels, significance of spectra, and passive sonar equation. Subsequent chapters discuss sound waves in liquids; acoustic radiation fundamentals; wind-generated ocean ambient noise; vibration isolation and structural damping; and radiation by plate flexural vibrations. Other chapters address cavitation, propeller cavitation noise, radiation by fluctuating-force (dipo

  14. Thermal noise engines

    CERN Document Server

    Kish, Laszlo B

    2010-01-01

    Electrical heat engines driven by the Johnson-Nyquist noise of resistors are introduced. They utilize Coulomb's law and the fluctuation-dissipation theorem of statistical physics that is the reverse phenomenon of heat dissipation in a resistor. No steams, gases, liquids, photons, fuel, combustion, phase transition, or exhaust/pollution are present here. In these engines, instead of heat reservoirs, cylinders, pistons and valves, resistors, capacitors and switches are the building elements. For the best performance, a large number of parallel engines must be integrated and the characteristic size of the elementary engine must be at the 10 nanometers scale. At room temperature, in the most idealistic case, a two-dimensional ensemble of engines of 25 nanometer characteristic size integrated on a 2.5x2.5 cm silicon wafer with 12 Celsius degree temperature difference between the warm-source and the cold-sink would produce a specific power of about 0.8 Watt. Regular and coherent (correlated-cylinder states) version...

  15. The management of complex system innovations. A theoretic approach to network formation and critical success factor identification using the case of fuel cell vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Venghaus, Sandra

    2011-07-01

    Given the economic, ecological and social importance of automotive transportation, the development of alternative fueling and propulsion technologies requires a wise and sustainable political course of action. Not least the public debate on the impact of transport emissions on climate change and the call for limits to automotive CO-2-emissions reflect the relevance of the topic. In the search for innovative alternatives to the conventional gasoline or diesel propulsion technology, electromobility and hydrogen-based fuel cell vehicles constitute the two most widely discussed long-term options. The market introduction of fuel cell vehicles serves as an expedient example of a highly complex system innovation (CSI), which requires the cooperation of a variety of actors from formerly independent economic sectors in order to overcome the significant barriers to market entry. As will be discussed, such CSI can only be successfully implemented in an environment, within which the complexity-induced knowledge gap is reduced by a systematic exchange of information with respect to both the critical success factors identified by each of the involved stakeholders as well as their cooperation needs and expectations. Given this challenge, a framework is developed, which serves as the basis for a structured dialogue among the multiple stakeholders involved in the development process of a complex system innovation. The framework can thus best be classified as a corporate moderation and decision-support tool to achieve transparency in and impose structure on complex contexts. Methodically, the presented thesis addresses the development of a holistic approach to the management of complex system innovations from two perspectives: (1) a theoretical perspective of analyzing underlying structures and processes of CSI management (i.e., the CSI Management Framework), as well as (2) the development of a strategic approach for the practical implementation of CSI management in complex networks

  16. Core/Combustor Noise - Research Overview

    Science.gov (United States)

    Hultgren, Lennart S.

    2017-01-01

    Contributions from the combustor to the overall propulsion noise of civilian transport aircraft are starting to become important due to turbofan design trends and advances in mitigation of other noise sources. Future propulsion systems for ultra-efficient commercial air vehicles are projected to be of increasingly higher bypass ratio from larger fans combined with much smaller cores, with ultra-clean burning fuel-flexible combustors. Unless effective noise-reduction strategies are developed, combustor noise is likely to become a prominent contributor to overall airport community noise in the future. This presentation gives a brief overview of the NASA outlook on pertinent issues and far-term research needs as well as current and planned research in the core/combustor-noise area. The research described herein is aligned with the NASA Ultra-Efficient Commercial Transport strategic thrust and is supported by the NASA Advanced Air Vehicle Program, Advanced Air Transport Technology Project, under the Aircraft Noise Reduction Subproject. The overarching goal of the Advanced Air Transport Technology (AATT) Project is to explore and develop technologies and concepts to revolutionize the energy efficiency and environmental compatibility of fixed wing transport aircrafts. These technological solutions are critical in reducing the impact of aviation on the environment even as this industry and the corresponding global transportation system continue to grow.

  17. On the effect of temperature on the threshold stress intensity factor of delayed hydride cracking in light water reactor fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Holston, Anna-MariaAlvarez; Stjarnsater, Johan [Studsvik Nuclear AB, Nykoping (Sweden)

    2017-06-15

    Delayed hydride cracking (DHC) was first observed in pressure tubes in Canadian CANDU reactors. In light water reactors, DHC was not observed until the late 1990s in high-burnup boiling water reactor (BWR) fuel cladding. In recent years, the focus on DHC has resurfaced in light of the increased interest in the cladding integrity during interim conditions. In principle, all spent fuel in the wet pools has sufficient hydrogen content for DHC to operate below 300°C. It is therefore of importance to establish the critical parameters for DHC to operate. This work studies the threshold stress intensity factor (K{sub IH}) to initiate DHC as a function of temperature in Zry-4 for temperatures between 227°C and 315°C. The experimental technique used in this study was the pin-loading testing technique. To determine the K{sub IH}, an unloading method was used where the load was successively reduced in a stepwise manner until no cracking was observed during 24 hours. The results showed that there was moderate temperature behavior at lower temperatures. Around 300°C, there was a sharp increase in K{sub IH} indicating the upper temperature limit for DHC. The value for K{sub IH} at 227°C was determined to be 2.6 ± 0.3 MPa √m.

  18. Fuel distribution

    Energy Technology Data Exchange (ETDEWEB)

    Tison, R.R.; Baker, N.R.; Blazek, C.F.

    1979-07-01

    Distribution of fuel is considered from a supply point to the secondary conversion sites and ultimate end users. All distribution is intracity with the maximum distance between the supply point and end-use site generally considered to be 15 mi. The fuels discussed are: coal or coal-like solids, methanol, No. 2 fuel oil, No. 6 fuel oil, high-Btu gas, medium-Btu gas, and low-Btu gas. Although the fuel state, i.e., gas, liquid, etc., can have a major impact on the distribution system, the source of these fuels (e.g., naturally-occurring or coal-derived) does not. Single-source, single-termination point and single-source, multi-termination point systems for liquid, gaseous, and solid fuel distribution are considered. Transport modes and the fuels associated with each mode are: by truck - coal, methanol, No. 2 fuel oil, and No. 6 fuel oil; and by pipeline - coal, methane, No. 2 fuel oil, No. 6 oil, high-Btu gas, medium-Btu gas, and low-Btu gas. Data provided for each distribution system include component makeup and initial costs.

  19. Spin Noise Exchange in Coupled Alkali-Metal Vapors

    CERN Document Server

    Dellis, A T; Kominis, I K

    2013-01-01

    The physics of spin exchange collisions has fueled a large number of discoveries in fundamental physics, chemistry and biology, and has led to several applications in medical imaging and nuclear magnetic resonance. We here report on the experimental observation and theoretical justification of a novel effect, the transfer of spin noise from one atomic species to another, through the mechanism of spin exchange. Essentially, we extend the foundational studies of spin exchange into the deeper layer of quantum fluctuations. The signature of spin noise exchange is an increase of the total spin noise power at low magnetic fields where the two-species spin noise resonances overlap.

  20. Road-traffic noise: annoyance, risk perception, and noise sensitivity in the Finnish adult population.

    Science.gov (United States)

    Okokon, Enembe Oku; Turunen, Anu W; Ung-Lanki, Sari; Vartiainen, Anna-Kaisa; Tiittanen, Pekka; Lanki, Timo

    2015-05-26

    Exposure to road-traffic noise commonly engenders annoyance, the extent of which is determined by factors not fully understood. Our aim was to estimate the prevalence and determinants of road-traffic noise annoyance and noise sensitivity in the Finnish adult population, while comparing the perceptions of road-traffic noise to exhausts as environmental health problems. Using a questionnaire that yielded responses from 1112 randomly selected adult Finnish respondents, we estimated road-traffic noise- and exhausts-related perceived exposures, health-risk perceptions, and self-reported annoyance on five-point scales, while noise sensitivity estimates were based on four questions. Determinants of noise annoyance and sensitivity were investigated using multivariate binary logistic regression and linear regression models, respectively. High or extreme noise annoyance was reported by 17% of respondents. Noise sensitivity scores approximated a Gaussian distribution. Road-traffic noise and exhausts were, respectively, considered high or extreme population-health risks by 22% and 27% of respondents. Knowledge of health risks from traffic noise, OR: 2.04 (1.09-3.82) and noise sensitivity, OR: 1.07 (1.00-1.14) were positively associated with annoyance. Knowledge of health risks (pnoise sensitivity. Age and sex were associated with annoyance and sensitivity only in bivariate models. A considerable proportion of Finnish adults are highly annoyed by road-traffic noise, and perceive it to be a significant health risk, almost comparable to traffic exhausts. There is no distinct noise-sensitive population subgroup. Knowledge of health risks of road-traffic noise, and attitudinal variables are associated with noise annoyance and sensitivity.

  1. Low Frequency Noise Measurement and Analysis of Capacitive Micro-Accelerometers: Temperature Effect

    Science.gov (United States)

    Mohd-Yasin, Faisal; Nagel, David J.; Ong, D. S.; Korman, Can E.; Chuah, H. T.

    2008-06-01

    A noise measurements of micro-accelerometers were performed using a special measurement system. A common spectral behavior of noise is found, with 1/ f noise dominating at low frequencies and white thermal noise being the limiting factor at higher frequencies. A temperature dependent and an acceleration dependant of the noise are found in the accelerometers, in agreement and contract of the theories, respectively.

  2. Solar noise storms

    CERN Document Server

    Elgaroy, E O

    2013-01-01

    Solar Noise Storms examines the properties and features of solar noise storm phenomenon. The book also presents some theories that can be used to gain a better understanding of the phenomenon. The coverage of the text includes topics that cover the features and behavior of noise storms, such as the observable features of noise storms; the relationship between noise storms and the observable features on the sun; and ordered behavior of storm bursts in the time-frequency plane. The book also covers the spectrum, polarization, and directivity of noise storms. The text will be of great use to astr

  3. Effects of environmental factors on corrosion behaviors of metal-fiber porous components in a simulated direct methanol fuel cell environment

    Institute of Scientific and Technical Information of China (English)

    Wei Yuan; Bo Zhou; Yong Tang; Zhao-chun Zhang; Jun Deng

    2014-01-01

    To enable the use of metallic components in direct methanol fuel cells (DMFCs), issues related to corrosion resistance must be considered because of an acid environment induced by the solid electrolyte. In this study, we report the electrochemical behaviors of metal-fiber-based porous sintered components in a simulated corrosive environment of DMFCs. Three materials were evaluated:pure copper, AISI304, and AISI316L. The environmental factors and related mechanisms affecting the corrosion behaviors were analyzed. The results demonstrated that AISI316L exhibits the best performance. A higher SO42-concentration increases the risk of material corrosion, whereas an increase in methanol concentration inhibits corrosion. The morphological features of the corroded samples were also characterized in this study.

  4. Helicopter Noise And Noise Abatement Procedures

    Directory of Open Access Journals (Sweden)

    Borivoj Galović

    2004-03-01

    Full Text Available The helicopter generated noise at and around the airports islower than the noise generated by aeroplanes, since their numberof operations, i. e. the number of takeoffs and landings ismuch lower than the takeoffs and landings of the aeroplanes.Out of some hundred operations a day, helicopters participatewith approximately 15%, but the very impact of noise is by nomeans negligible, since the number of helicopter flights aboveurban areas is constantly increasing.This paper attempts to analyse this phenomenon and thetype of helicopter generated noise, its negative impacts, to explainthe flight procedures and the operative procedures duringtakeoff, landing and overflight of helicopters in operations inthe vicinity and outside airports, as well as the methods of measuringand determining the limit of noise [eve~ and the resultingproblems.

  5. Factors Nuclear Power Plant Fuel Cost Factor Analysis%核电厂核燃料成本的影响因素分析

    Institute of Scientific and Technical Information of China (English)

    陈诚

    2016-01-01

    近年来,随着我国经济建设体系的不断发展完善,能源需求量在日益增长的同时,也对能源的经济性提出了更高的要求和标准。相较于水电、风电的市场价格,核电价格无疑最具优势。但由于核燃料自身的成本较高,增加了核电厂管理运营的难度,制约了核电市场竞争力的进一步提升。%In recent years,with the continuous development and improvement of China's economic construction system,energy demand is growing,but also on energy economy put forward higher requirements and standards.Hydropower,wind power coMPared to the market price,nuclear power is undoubtedly the most advantageous price.However,due to the higher cost of fuel itself,increase the difficulty of operating a nuclear power plant management,restricted further enhance the market competitiveness of nuclear power.

  6. Modularity, noise, and natural selection.

    Science.gov (United States)

    Marroig, Gabriel; Melo, Diogo A R; Garcia, Guilherme

    2012-05-01

    Most biological systems are formed by component parts that are to some degree interrelated. Groups of parts that are more associated among themselves and are relatively autonomous from others are called modules. One of the consequences of modularity is that biological systems usually present an unequal distribution of the genetic variation among traits. Estimating the covariance matrix that describes these systems is a difficult problem due to a number of factors such as poor sample sizes and measurement errors. We show that this problem will be exacerbated whenever matrix inversion is required, as in directional selection reconstruction analysis. We explore the consequences of varying degrees of modularity and signal-to-noise ratio on selection reconstruction. We then present and test the efficiency of available methods for controlling noise in matrix estimates. In our simulations, controlling matrices for noise vastly improves the reconstruction of selection gradients. We also perform an analysis of selection gradients reconstruction over a New World Monkeys skull database to illustrate the impact of noise on such analyses. Noise-controlled estimates render far more plausible interpretations that are in full agreement with previous results. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  7. Noise exposure under hyperbaric conditions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-01

    Objective evidence exists that divers demonstrate a hearing deficit greater than would be expected from ageing effects alone. Deafness in divers may be caused by a number of factors other than exposure to excessive noise levels, eg barotrauma, ear infection etc. This review concentrates on the concern that exposure of commercial divers to noise while at work may cause a hearing deficit. Sound pressure levels recorded both underwater and in diving chambers often exceed those allowable to workers onshore. However, the sound perceived by the diver is modified both in amplitude and in frequency when he is either underwater or in pressurised chambers. Broadly the effect of this modification is to attenuate the sound and thus offer some protection from high noise levels. The degree of attentuation varies with the frequency of the sound, however it is also possible under specific conditions associated with gas density for the sensitivity to particular frequencies to be amplified above that for normal atmospheric air. The levels of sound observed from some underwater tools are of concern even after allowing for a significant de-sensitisation of the divers` hearing. Reports of tinnitus and temporary hearing loss following a dive are sure signs that the noise levels have been harmful. It is not possible at present to describe risk criteria for hearing damage due to noise exposure associated with diving. (author)

  8. Fuel Cells

    DEFF Research Database (Denmark)

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Fuel cells have been the subject of intense research and development efforts for the past decades. Even so, the technology has not had its commercial breakthrough yet. This entry gives an overview of the technological challenges and status of fuel cells and discusses the most promising applications...... of the different types of fuel cells. Finally, their role in a future energy supply with a large share of fluctuating sustainable power sources, e.g., solar or wind, is surveyed....

  9. Noise Gating Solar Images

    Science.gov (United States)

    DeForest, Craig; Seaton, Daniel B.; Darnell, John A.

    2017-08-01

    I present and demonstrate a new, general purpose post-processing technique, "3D noise gating", that can reduce image noise by an order of magnitude or more without effective loss of spatial or temporal resolution in typical solar applications.Nearly all scientific images are, ultimately, limited by noise. Noise can be direct Poisson "shot noise" from photon counting effects, or introduced by other means such as detector read noise. Noise is typically represented as a random variable (perhaps with location- or image-dependent characteristics) that is sampled once per pixel or once per resolution element of an image sequence. Noise limits many aspects of image analysis, including photometry, spatiotemporal resolution, feature identification, morphology extraction, and background modeling and separation.Identifying and separating noise from image signal is difficult. The common practice of blurring in space and/or time works because most image "signal" is concentrated in the low Fourier components of an image, while noise is evenly distributed. Blurring in space and/or time attenuates the high spatial and temporal frequencies, reducing noise at the expense of also attenuating image detail. Noise-gating exploits the same property -- "coherence" -- that we use to identify features in images, to separate image features from noise.Processing image sequences through 3-D noise gating results in spectacular (more than 10x) improvements in signal-to-noise ratio, while not blurring bright, resolved features in either space or time. This improves most types of image analysis, including feature identification, time sequence extraction, absolute and relative photometry (including differential emission measure analysis), feature tracking, computer vision, correlation tracking, background modeling, cross-scale analysis, visual display/presentation, and image compression.I will introduce noise gating, describe the method, and show examples from several instruments (including SDO

  10. Noise-Measuring Method

    DEFF Research Database (Denmark)

    Diamond, J. M.

    1965-01-01

    A noise-measuring method based on the use of a calibrated noise generator and an output meter with a special scale is described. The method eliminates the effect of noise contributions occurring in the circuits following the device under test....

  11. Introductory guide to noise

    CSIR Research Space (South Africa)

    Ferreira, T.M

    1973-01-01

    Full Text Available The difference between sound and noise varies from one human being to another. Noise, then, is simply unwanted sound and to understand how it can be combatted we must know more about its nature. A guide of acceptable levels of noise are investigated....

  12. Feasibility study of a mini fuel cell to detect interference from a cellular phone

    Science.gov (United States)

    Abdullah, M. O.; Gan, Y. K.

    Fuel cells produce electricity without involving combustion processes. They generate no noise, vibration or air pollution and are therefore suitable for use in many vibration-free power-generating applications. In this study, a mini alkaline fuel cell signal detector system has been designed, constructed and tested. The initial results have shown the applicability of such system for used as an indicator of signal disturbance from cellular phones. A small disturbance even at 4 mV cm -1, corresponding to an amplitude of 12-18 mG in terms of electromagnetic field, can be well detected by such a device. Subsequently, a thermodynamics model has been developed to provide a parametric study by simulation to show the likely performance of the fuel cell alone in other environments. As such the model can provide many useful generic design data for alkaline fuel cells. Two general conclusions can be drawn from the present theoretical study: (i) fuel cell performance increases with temperature, pressure and correction factor, C f; (ii) the temperature factor (E/ T) increases with increasing temperature and with increasing pressure factor.

  13. Cognition and aided speech recognition in noise: specific role for cognitive factors following nine-week experience with adjusted compression settings in hearing aids.

    Science.gov (United States)

    Rudner, Mary; Foo, Catharina; Rönnberg, Jerker; Lunner, Thomas

    2009-10-01

    The working memory model for Ease of Language Understanding (ELU) proposes that language understanding under taxing conditions is related to explicit cognitive capacity. We refer to this as the mismatch hypothesis, since phonological representations based on the processing of speech under established conditions may not be accessed so readily when input conditions change and a match becomes problematic. Then, cognitive capacity requirements may differ from those used for processing speech hitherto. In the present study, we tested this hypothesis by investigating the relationship between aided speech recognition in noise and cognitive capacity in experienced hearing aid users when there was either a match or mismatch between processed speech input and established phonological representations. The settings in the existing digital hearing aids of the participants were adjusted to one of two different compression settings which processed the speech signal in qualitatively different ways ("fast" or "slow"). Testing took place after a 9-week period of experience with the new setting. Speech recognition was tested under different noise conditions and with match or mismatch (i.e. alternative compression setting) manipulations of the input signal. Individual cognitive capacity was measured using a reading span test and a letter monitoring test. Reading span, a reliable measure of explicit cognitive capacity, predicted speech recognition performance under mismatch conditions when processed input was incongruent with recently established phonological representations, due to the specific hearing aid setting. Cognitive measures were not main predictors of performance under match conditions. These findings are in line with the ELU model.

  14. Ultra Low Noise Poroelastic Road Surfaces

    Directory of Open Access Journals (Sweden)

    Jerzy A. Ejsmont

    2016-04-01

    Full Text Available Noise is one of the most important environmental problems related to road traffic. During the last decades, the noise emitted by the engines and powertrains of vehicles was greatly reduced and tires became a clearly dominant noise source. The article describes the concept of low noise poroelastic road surfaces that are composed of mineral and rubber aggregate bound by polyurethane resin. Those surfaces have a porous structure and are much more flexible than standard asphalt or cement concrete pavements due to high content of rubber aggregate and elastic binder. Measurements performed in several European countries indicate that such surfaces decrease tire/road noise between 7 dB and 12 dB with respect to reference surfaces such as dense asphalt concrete or stone matrix asphalt. Furthermore, poroelastic road surfaces ascertain the rolling resistance of car tires, which is comparable to classic pavements. One of the unforeseen properties of the poroelastic road surfaces is their ability to decrease the risks related to car fires with fuel spills. The article presents the road and laboratory results of noise, rolling resistance, and fire tests performed on a few types of poroelastic road surfaces.

  15. Shot noise of a quantum shuttle

    DEFF Research Database (Denmark)

    Novotny, Tomas; Donarini, Andrea; Flindt, Christian

    2004-01-01

    even in the quantum limit, confirming that shuttling is universally a low noise phenomenon. In approaching the semiclassical limit, the Fano factor shows a giant enhancement (Fsimilar or equal to10(2)) at the shuttling threshold, consistent with predictions based on phase-space representations......We formulate a theory for shot noise in quantum nanoelectromechanical systems. As a specific example, the theory is applied to a quantum shuttle, and the zero-frequency noise, measured by the Fano factor F, is computed. F reaches very low values (Fsimilar or equal to10(-2)) in the shuttling regime...

  16. Long-term maintenance of reducing conditions in a spent nuclear fuel repository. A re-examination of critical factors

    Energy Technology Data Exchange (ETDEWEB)

    Gascoyne, M. [Gascoyne GeoProjects Inc, Pinawa, MB (Canada)

    1999-04-01

    Penetration of oxidising groundwaters to depths of 500 m in a permeable bedrock, over a glacial/interglacial cycle, may compromise the stability of a spent nuclear fuel repository and cause the release and migration towards the surface of actinides and associated fission products. This report examines the potential for the penetration of oxygen (O{sub 2}) to depths of 500 m in a fractured crystalline rock environment, typical of the Fennoscandian Shield. Previous studies performed for the Swedish program of nuclear waste disposal (principally the SITE-94 safety assessment) have indicated that O{sub 2} might reach repository depths during a deglaciation when melt-water from the base of an ice sheet could enter the bedrock, driven by strong hydraulic gradients. This report re-examines aspects of this scenario and finds that: 1. The capacity of flow-path minerals to scavenge O{sub 2} from recharging groundwater may be lower than expected due to a previously unrecognised depletion of Fe(II)-bearing minerals in the active flow-paths in a fractured crystalline rock. 2. Assumptions in the SITE-94 assessment, such as the use of a continental-scale flow model, the lack of structural controls on groundwater flow, a preferred horizontal permeability, and the use of permeabilities to depths of 10 km that are up to two orders of magnitude greater than comparable environments, are disproportionately simplistic and represent an extremely conservative case. 3. Assumptions of a thin, discontinuous permafrost, a warm-based ice sheet, and high-O{sub 2} content melt-water at the repository site are unrealistic and overly conservative. A more realistic scenario, which includes a greater influence of permafrost, a cold based ice sheet, lower bedrock permeabilities and a more-limited, regional-scale flow path, is recommended as being more appropriate for use in the safety assessment. Under this revised scenario, it is believed that O{sub 2} will not penetrate to repository depths over

  17. Self-reported sleep disturbances due to railway noise: exposure-response relationships for nighttime equivalent and maximum noise levels.

    Science.gov (United States)

    Aasvang, Gunn Marit; Moum, Torbjorn; Engdahl, Bo

    2008-07-01

    The objective of the present survey was to study self-reported sleep disturbances due to railway noise with respect to nighttime equivalent noise level (L(p,A,eq,night)) and maximum noise level (L(p,A,max)). A sample of 1349 people in and around Oslo in Norway exposed to railway noise was studied in a cross-sectional survey to obtain data on sleep disturbances, sleep problems due to noise, and personal characteristics including noise sensitivity. Individual noise exposure levels were determined outside of the bedroom facade, the most-exposed facade, and inside the respondents' bedrooms. The exposure-response relationships were analyzed by using logistic regression models, controlling for possible modifying factors including the number of noise events (train pass-by frequency). L(p,A,eq,night) and L(p,A,max) were significantly correlated, and the proportion of reported noise-induced sleep problems increased as both L(p,A,eq,night) and L(p,A,max) increased. Noise sensitivity, type of bedroom window, and pass-by frequency were significant factors affecting noise-induced sleep disturbances, in addition to the noise exposure level. Because about half of the study population did not use a bedroom at the most-exposed side of the house, the exposure-response curve obtained by using noise levels for the most-exposed facade underestimated noise-induced sleep disturbance for those who actually have their bedroom at the most-exposed facade.

  18. A Goldilocks principle for modeling radial velocity noise

    CERN Document Server

    Feng, Fabo; Jones, H R A; Butler, R P; Vogt, S

    2016-01-01

    The doppler measurements of stars are diluted and distorted by stellar activity noise. Different choices of noise models and statistical methods have led to much controversy in the confirmation of exoplanet candidates obtained through analysing radial velocity data. To quantify the limitation of various models and methods, we compare different noise models and signal detection criteria for various simulated and real data sets in the Bayesian framework. According to our analyses, the white noise model tend to interpret noise as signal, leading to false positives. On the other hand, the red noise models are likely to interprete signal as noise, resulting in false negatives. We find that the Bayesian information criterion combined with a Bayes factor threshold of 150 can efficiently rule out false positives and confirm true detections. We further propose a Goldilocks principle aimed at modeling radial velocity noise to avoid too many false positives and too many false negatives. We propose that the noise model w...

  19. Adaptive Noise Reduction System

    Directory of Open Access Journals (Sweden)

    Ivana Ropuš

    2013-01-01

    Full Text Available Noise is an all-present environment pollutant, considered to be one of the greatest contemporary pollutants. World-wide, co-ordinated actions are conducted in order to develop systems which minimise the noise influence onto society.In this article we argue that novel approach to suppression of influence of noise is useful. Furthermore, we argue that the efficient approach is formulation of the efficient, broadly applicable, ubiquituous, adaptive noise-protection system. The approach combines the natural noise-protection form based on plants with the artificially formed coatings.Elements of the system are discussed, its formation and maintenance analysed and perspectives conjectured.

  20. Taguchi Method for Investigating the Performance Parameters and Exergy of a Diesel Engine Using Four Types of Diesel Fuels

    Directory of Open Access Journals (Sweden)

    Dara K. Khidir

    2016-05-01

    Full Text Available The effects of changes in engine operating parameters, i.e., engine speed, throttle and water temperature, for four types of diesel fuel (A, B, C and D of different specific gravities, as supplied from local market and refineries, were studied and simultaneously optimized. The experiment design was based on Taguchi’s “L' 16” orthogonal table, and the engine was put to test at different engine speeds, throttling opening percentages and water temperatures, using different fuels. The data were analyzed using S/N (signal to noise ratio for each factor. The obtained results show that the optimum operating conditions for minimum BSFC (brake specific fuel consumption are achieved when the engine speed is 2500 rpm, the throttle is placed at 75% of full throttling, the water temperature is 80 oC and the engine is using fuel type D. Also, results of S/N ratio reveal that the throttle has significant influence on brake thermal and exergic efficiencies. Water temperature is the second most effective factor and then comes the influence of engine speed. The least effective factor among the studied parameters for the types of fuel considered in this experiment is the fuel type.

  1. Ambient air quality measurements from a continuously moving mobile platform: Estimation of area-wide, fuel-based, mobile source emission factors using absolute principal component scores

    Science.gov (United States)

    Larson, Timothy; Gould, Timothy; Riley, Erin A.; Austin, Elena; Fintzi, Jonathan; Sheppard, Lianne; Yost, Michael; Simpson, Christopher

    2017-03-01

    We have applied the absolute principal component scores (APCS) receptor model to on-road, background-adjusted measurements of NOx, CO, CO2, black carbon (BC), and particle number (PN) obtained from a continuously moving platform deployed over nine afternoon sampling periods in Seattle, WA. Two Varimax-rotated principal component features described 75% of the overall variance of the observations. A heavy-duty vehicle feature was correlated with black carbon and particle number, whereas a light-duty feature was correlated with CO and CO2. NOx had moderate correlation with both features. The bootstrapped APCS model predictions were used to estimate area-wide, average fuel-based emission factors and their respective 95% confidence limits. The average emission factors for NOx, CO, BC and PN (14.8, 18.9, 0.40 g/kg, and 4.3 × 1015 particles/kg for heavy duty vehicles, and 3.2, 22.4, 0.016 g/kg, and 0.19 × 1015 particles/kg for light-duty vehicles, respectively) are consistent with previous estimates based on remote sensing, vehicle chase studies, and recent dynamometer tests. Information on the spatial distribution of the concentrations contributed by these two vehicle categories relative to background during the sampling period was also obtained.

  2. Low-noise amplifier

    Directory of Open Access Journals (Sweden)

    V. B. Gulkov

    2012-11-01

    Full Text Available The mixture of signal and noise processing device is considered in this article. It contains two channels: the main channel (MC contains the mixture of signal and noise, and compensation channel (CC that extracts just a noise from the mixture. The feature of the processing circuit is that the mixture samples are formed by short impulses at the moments of passing signal through zero. Further antiphase noise is set in the channels, adder by which the noise is removed from mixture is set on the cannels output. Study of the described device was carried out for simulated AM signal and white Gaussian noise in simulation environment Matlab. The results are shown, that device reduces noise by 16 dB of power.

  3. Noise from wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Fegeant, Olivier [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Building Sciences

    2002-02-01

    A rapid growth of installed wind power capacity is expected in the next few years. However, the siting of wind turbines on a large scale raises concerns about their environmental impact, notably with respect to noise. To this end, variable speed wind turbines offer a promising solution for applications in densely populated areas like the European countries, as this design would enable an efficient utilisation of the masking effect due to ambient noise. In rural and recreational areas where wind turbines are sited, the ambient noise originates from the action of wind on the vegetation and about the listener's ear (pseudo-noise). It shows a wind speed dependence similar to that of the noise from a variable speed wind turbine and can therefore mask the latter for a wide range of conditions. However, a problem inherent to the design of these machines is their proclivity to pure tone generation, because of the enhanced difficulty of avoiding structural resonances in the mechanical parts. Pure tones are deemed highly annoying and are severely regulated by most noise policies. In relation to this problem, the vibration transmission of structure-borne sound to the tower of the turbine is investigated, in particular when the tower is stiffened at its upper end. Furthermore, since noise annoyance due to wind turbine is mostly a masking issue, the wind-related sources of ambient noise are studied and their masking potentials assessed. With this aim, prediction models for wind-induced vegetation noise and pseudo-noise have been developed. Finally, closely related to the effect of masking, is the difficulty, regularly encountered by local authorities and wind farm developers, to measure noise immission from wind turbines. A new measurement technique has thus been developed in the course of this work. Through improving the signal-to-noise ratio between wind turbine noise and ambient noise, the new technique yields more accurate measurement results.

  4. Frequency domain analysis of noise in autoregulated gene circuits

    OpenAIRE

    Simpson, Michael L.; Cox, Chris D.; Sayler, Gary S.

    2003-01-01

    We describe a frequency domain technique for the analysis of intrinsic noise within negatively autoregulated gene circuits. This approach is based on the transfer function around the feedback loop (loop transmission) and the equivalent noise bandwidth of the system. The loop transmission, T, is shown to be a determining factor of the dynamics and the noise behavior of autoregulated gene circuits, and this T-based technique provides a simple and flexible method for the analysis of noise arisin...

  5. What Do Contrast Threshold Equivalent Noise Studies Actually Measure? Noise vs. Nonlinearity in Different Masking Paradigms.

    Directory of Open Access Journals (Sweden)

    Alex S Baldwin

    Full Text Available The internal noise present in a linear system can be quantified by the equivalent noise method. By measuring the effect that applying external noise to the system's input has on its output one can estimate the variance of this internal noise. By applying this simple "linear amplifier" model to the human visual system, one can entirely explain an observer's detection performance by a combination of the internal noise variance and their efficiency relative to an ideal observer. Studies using this method rely on two crucial factors: firstly that the external noise in their stimuli behaves like the visual system's internal noise in the dimension of interest, and secondly that the assumptions underlying their model are correct (e.g. linearity. Here we explore the effects of these two factors while applying the equivalent noise method to investigate the contrast sensitivity function (CSF. We compare the results at 0.5 and 6 c/deg from the equivalent noise method against those we would expect based on pedestal masking data collected from the same observers. We find that the loss of sensitivity with increasing spatial frequency results from changes in the saturation constant of the gain control nonlinearity, and that this only masquerades as a change in internal noise under the equivalent noise method. Part of the effect we find can be attributed to the optical transfer function of the eye. The remainder can be explained by either changes in effective input gain, divisive suppression, or a combination of the two. Given these effects the efficiency of our observers approaches the ideal level. We show the importance of considering these factors in equivalent noise studies.

  6. Noise Scaling and Community Noise Metrics for the Hybrid Wing Body Aircraft

    Science.gov (United States)

    Burley, Casey L.; Brooks, Thomas F.; Hutcheson, Florence V.; Doty, Michael J.; Lopes, Leonard V.; Nickol, Craig L.; Vicroy, Dan D.; Pope, D. Stuart

    2014-01-01

    An aircraft system noise assessment was performed for the hybrid wing body aircraft concept, known as the N2A-EXTE. This assessment is a result of an effort by NASA to explore a realistic HWB design that has the potential to substantially reduce noise and fuel burn. Under contract to NASA, Boeing designed the aircraft using practical aircraft design princip0les with incorporation of noise technologies projected to be available in the 2020 timeframe. NASA tested 5.8% scale-mode of the design in the NASA Langley 14- by 22-Foot Subsonic Tunnel to provide source noise directivity and installation effects for aircraft engine and airframe configurations. Analysis permitted direct scaling of the model-scale jet, airframe, and engine shielding effect measurements to full-scale. Use of these in combination with ANOPP predictions enabled computations of the cumulative (CUM) noise margins relative to FAA Stage 4 limits. The CUM margins were computed for a baseline N2A-EXTE configuration and for configurations with added noise reduction strategies. The strategies include reduced approach speed, over-the-rotor line and soft-vane fan technologies, vertical tail placement and orientation, and modified landing gear designs with fairings. Combining the inherent HWB engine shielding by the airframe with added noise technologies, the cumulative noise was assessed at 38.7 dB below FAA Stage 4 certification level, just 3.3 dB short of the NASA N+2 goal of 42 dB. This new result shows that the NASA N+2 goal is approachable and that significant reduction in overall aircraft noise is possible through configurations with noise reduction technologies and operational changes.

  7. Noise performance of frequency modulation Kelvin force microscopy.

    Science.gov (United States)

    Diesinger, Heinrich; Deresmes, Dominique; Mélin, Thierry

    2014-01-02

    Noise performance of a phase-locked loop (PLL) based frequency modulation Kelvin force microscope (FM-KFM) is assessed. Noise propagation is modeled step by step throughout the setup using both exact closed loop noise gains and an approximation known as "noise gain" from operational amplifier (OpAmp) design that offers the advantage of decoupling the noise performance study from considerations of stability and ideal loop response. The bandwidth can be chosen depending on how much noise is acceptable and it is shown that stability is not an issue up to a limit that will be discussed. With thermal and detector noise as the only sources, both approaches yield PLL frequency noise expressions equal to the theoretical value for self-oscillating circuits and in agreement with measurement, demonstrating that the PLL components neither modify nor contribute noise. Kelvin output noise is then investigated by modeling the surrounding bias feedback loop. A design rule is proposed that allows choosing the AC modulation frequency for optimized sharing of the PLL bandwidth between Kelvin and topography loops. A crossover criterion determines as a function of bandwidth, temperature and probe parameters whether thermal or detector noise is the dominating noise source. Probe merit factors for both cases are then established, suggesting how to tackle noise performance by probe design. Typical merit factors of common probe types are compared. This comprehensive study is an encouraging step toward a more integral performance assessment and a remedy against focusing on single aspects and optimizing around randomly chosen key values.

  8. Motor Fuel Excise Taxes

    Energy Technology Data Exchange (ETDEWEB)

    2015-09-01

    A new report from the National Renewable Energy Laboratory (NREL) explores the role of alternative fuels and energy efficient vehicles in motor fuel taxes. Throughout the United States, it is common practice for federal, state, and local governments to tax motor fuels on a per gallon basis to fund construction and maintenance of our transportation infrastructure. In recent years, however, expenses have outpaced revenues creating substantial funding shortfalls that have required supplemental funding sources. While rising infrastructure costs and the decreasing purchasing power of the gas tax are significant factors contributing to the shortfall, the increased use of alternative fuels and more stringent fuel economy standards are also exacerbating revenue shortfalls. The current dynamic places vehicle efficiency and petroleum use reduction polices at direct odds with policies promoting robust transportation infrastructure. Understanding the energy, transportation, and environmental tradeoffs of motor fuel tax policies can be complicated, but recent experiences at the state level are helping policymakers align their energy and environmental priorities with highway funding requirements.

  9. Spectra for the product of Gaussian noises

    CERN Document Server

    Kish, L B; Gingl, Z; Granqvist, C G

    2012-01-01

    Products of Gaussian noises often emerge as the result of non-linear detection techniques or as a parasitic effect, and their proper handling is important in many practical applications, including in fluctuation-enhanced sensing, indoor air or environmental quality monitoring, etc. We use Rice's random phase oscillator formalism to calculate the power density spectra variance for the product of two Gaussian band-limited white noises with zero-mean and the same bandwidth W. The ensuing noise spectrum is found to decrease linearly from zero frequency to 2W, and it is zero for frequencies greater than 2W. Analogous calculations performed for the square of a single Gaussian noise confirm earlier results. The spectrum at non-zero frequencies, and the variance of the square of a noise, is amplified by a factor two as a consequence of correlation effects between frequency products. Our analytic results is corroborated by computer simulations.

  10. Low-noise amplifiers for satellite communications

    Science.gov (United States)

    Whelehan, J.

    1984-02-01

    It is pointed out that over the past several years significant advances have been made in the overall capability of both microwave and mm-wave receivers. This is particularly apparent in the telecom market. Integral parts of advanced receiver technology are low-noise receivers. The advances currently being achieved in low-noise technology are partly based on developments in GaAs semiconductor technology. The development of high-cutoff-frequency beam lead mixer diodes has led to the development of mm-wave low-noise mixers with excellent low-noise capability. The advanced techniques are now being employed in field-deployable systems. Low noise is an important factor in satellite communications applications. Attention is given to C-band fixed satellite service, C-band parametric amplifiers, C-band FET, and X band, the Ku band, and the 30/20 GHz band.

  11. assessment of noise pollutio noise pollutio noise pollution from ...

    African Journals Online (AJOL)

    eobe

    sawmill noise on the metropolis was developed. the metropolis was ... INTRODUCTION. INTRODUCTION ... auditory fatigue and hearing loss, and indirect n auditory effects such as speech interfere annoyance .... acoustic environment for workers [29]. In particular, ..... and corn mills”, African Journal of Health Science,. Vol.

  12. Fuel cells:

    DEFF Research Database (Denmark)

    Sørensen, Bent

    2013-01-01

    A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil and nucl......A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil...... and nuclear fuel-based energy technologies....

  13. Noise removal in multichannel image data by a parametric maximum noise fraction estimator

    DEFF Research Database (Denmark)

    Conradsen, Knut; Ersbøll, Bjarne Kjær; Nielsen, Allan Aasbjerg

    1991-01-01

    Some approaches to noise removal in multispectral imagery are presented. The primary contribution of the present work is the establishment of several ways of estimating the noise covariance matrix from image data and a comparison of the noise separation performances. A case study with Landsat MSS...... data demonstrates that the principal components are not sorted correctly in terms of visual image quality, whereas the minimum/maximum autocorrelation factors and the maximum noise fractions (MAFs) are. A case study with Landsat TM data shows an ordering which is consistent with the spatial wavelength...... in the components. The case studies indicate that a better noise separation is attained when using more complex noise models than the simple model implied by MAF analysis. (L.M.)...

  14. Adaptive noise cancellation

    CERN Document Server

    Akram, N

    1999-01-01

    In this report we describe the concept of adaptive noise canceling, an alternative method of estimating signals corrupted by additive noise of interference. The method uses 'primary' input containing the corrupted signal and a 'reference' input containing noise correlated in some unknown way with the primary noise, the reference input is adaptively filtered and subtracted from the primary input to obtain the signal estimate. Adaptive filtering before subtraction allows the treatment of inputs that are deterministic or stochastic, stationary or time variable. When the reference input is free of signal and certain other conditions are met then noise in the primary input can be essentially eliminated without signal distortion. It is further shown that the adaptive filter also acts as notch filter. Simulated results illustrate the usefulness of the adaptive noise canceling technique.

  15. Acceptable noise level

    DEFF Research Database (Denmark)

    Olsen, Steen Østergaard; Nielsen, Lars Holme; Lantz, Johannes;

    2012-01-01

    The acceptable noise level (ANL) is used to quantify the amount of background noise that subjects can accept while listening to speech, and is suggested for prediction of individual hearing-aid use. The aim of this study was to assess the repeatability of the ANL measured in normal-hearing subjec...... using running Danish and non-semantic speech materials as stimuli and modulated speech-spectrum and multi-talker babble noises as competing stimuli....

  16. Noise at the Interface

    DEFF Research Database (Denmark)

    Prior, Andrew

    2011-01-01

    The notion of noise occupies a contested territory, in which it is framed as pollution and detritus even as it makes its opposite a possibility - noise is always defined in opposition to something else, even if this ‘other’ is not quite clear. This paper explores noise in the context of ‘the inte...... interface’ asking what its affordances as an idea may contribute to our understanding of interface. I draw historically on information theory in particular to initiate this exploration....

  17. Internal noise estimates correlate with autistic traits.

    Science.gov (United States)

    Vilidaite, Greta; Yu, Miaomiao; Baker, Daniel H

    2017-08-01

    Previous neuroimaging research has reported increased internal (neural) noise in sensory systems of autistic individuals. However, it is unclear if this difference has behavioural or perceptual consequences, as previous attempts at measuring internal noise in ASD psychophysically have been indirect. Here, we use a "gold standard" psychophysical double-pass paradigm to investigate the relationship between internal noise and autistic traits in the neurotypical population (n = 43). We measured internal noise in three tasks (contrast perception, facial expression intensity perception, and number summation) to estimate a global internal noise factor using principal components analysis. This global internal noise was positively correlated with autistic traits (rs  = 0.32, P = 0.035). This suggests that increased internal noise is associated with the ASD phenotype even in subclinical populations. The finding is discussed in relation to the neural and genetic basis of internal noise in ASD. Autism Res 2017, 10: 1384-1391. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

  18. Fuel cells

    Directory of Open Access Journals (Sweden)

    D. N. Srivastava

    1962-05-01

    Full Text Available The current state of development of fuel cells as potential power sources is reviewed. Applications in special fields with particular reference to military requirements are pointed out.

  19. Landing gear noise attenuation

    Science.gov (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  20. Future Fuels

    Science.gov (United States)

    2006-04-01

    Storage Devices, Fuel Management, Gasification, Fischer-Tropsch, Syngas , Hubberts’s Peak UNCLAS UNCLAS UNCLAS UU 80 Dr. Sujata Millick (703) 696...prices ever higher, and perhaps lead to intermittent fuel shortages as production fluctuates. Clearly, this competition for resources also provides oil...producers multiple options for selling their products, and raises the possibility that the US could face shortages resulting from shifts in

  1. NOISE AND SENSITIVITY IN POLYSILICON PIEZORESISTIVE CANTILEVERS*

    Institute of Scientific and Technical Information of China (English)

    于晓梅; 江兴流; J.THAYSEN; O.HANSEN; A.BOISEN

    2001-01-01

    Piezoresistive cantilevers with dimensions of 200 × 50 × 1.8μm3 have been fabricated from polycrystalline silicon using reactive ion etching (RIE) and back etching processes. Full Wheatstone bridges have been designed symmetrically on-chip, with two resistors placed on the cantilevers and two resistors on the substrate. The differential measurements of the two cantilevers can reduce the thermal shift of the signal in the system and the external noise in the laboratory.The characteristics of the fabricated cantilevers have been analysed by measuring the noise and the sensitivity. The measured noise spectra show that the 1/f noise is the dominant noise source at low frequencies. With the linear relation between 1/f noise and bias voltages, the Hooge factor (c) was calculated to be 0.0067. The 1/f noise was explained in terms of a lattice scattering model, which occurs in the depletion region of the grains. The displacement sensitivity of the cantilevers was calculated to be 1× 10-6nm-1 by measuring the resistance change and the vertical deflection of the cantilever. The gauge factor of the piezoresistive cantilever was calculated to be 19. At a 3V bias voltage and 1000 Hz measurement bandwidth, 1 nm of minimum detectable deflection has been obtained.

  2. Fuel cell engineering

    CERN Document Server

    Sundmacher

    2012-01-01

    Fuel cells are attractive electrochemical energy converters featuring potentially very high thermodynamic efficiency factors. The focus of this volume of Advances in Chemical Engineering is on quantitative approaches, particularly based on chemical engineering principles, to analyze, control and optimize the steady state and dynamic behavior of low and high temperature fuel cells (PEMFC, DMFC, SOFC) to be applied in mobile and stationary systems. * Updates and informs the reader on the latest research findings using original reviews * Written by leading industry experts and scholars * Review

  3. Noise and Health: How does noise affect us?

    NARCIS (Netherlands)

    Miedema, H.M.E.

    2001-01-01

    Noise annoyance is a primary indication that noise is a problem, and by itself noise annoyance means that the quality of life is adversely affected. Results from noise annoyance research are presented that make possible a detailed evaluation of noise exposures with respect to the annoyance induced.

  4. Noise of high-performance aircraft at afterburner

    Science.gov (United States)

    Tam, Christopher K. W.; Parrish, Sarah A.

    2015-09-01

    The noise from a high-performance aircraft at afterburner is investigated. The main objective is to determine whether the dominant noise components are the same or similar to those of a hot supersonic laboratory jet. For this purpose, measured noise data from F-22A Raptors are analyzed. It is found, based on both spectral and directivity data, that there is a new dominant noise component in addition to the usual turbulent mixing noise. The characteristic features of the new noise component are identified. Measured data indicates that the new noise component is observed only when the rate of fuel burn of the engine is increased significantly above that of the intermediate power setting. This suggests that the new noise component is combustion related. The possibility that it is indirect combustion noise generated by the passage of hot spots from the afterburner through the nozzle of the jet is investigated. Because flow and temperature data were not measured in the F-22A engine tests, to provide support to the proposition, numerical simulations of indirect combustion noise generation due to the passing of an entropy wave pulse (a hot spot) through a military-style nozzle are carried out. Sound generation is observed at the front and at the back of the pulse. This creates a fast and a slow acoustic wave as the sound radiates out from the nozzle exit. Quantitative estimates of the principal directions of acoustic radiation due to the emitted fast and slow acoustic waves are made. It is found that there are reasonably good agreements with measured data. To estimate the intensity level (IL) of the radiated indirect combustion noise, a time-periodic entropy wave train of 15 percent temperature fluctuation is used as a model of the hot spots coming out of the afterburner. This yields an IL of 175.5 dB. This is a fairly intense noise source, well capable of causing the radiation of the new jet noise component.

  5. 多层套管燃料元件工程热点因子敏感性分析%Sensitivity Analysis of Engineering Hot Spot Factor for Multi-layer Tube Fuel Element

    Institute of Scientific and Technical Information of China (English)

    胡跃春; 邓才玉; 李海涛; 徐涛忠

    2014-01-01

    为保证反应堆的安全,并对燃料元件的制造加工提出合理可行的要求,从元件制造加工和反应堆运行测量两方面对多层套管燃料元件工程热点因子的敏感性进行了分析。结果表明:流道间隙偏差直接影响元件热源的导出,由此引起的工程热点因子造成的温升较大。%For ensuring reactor safety and putting forward reasonable requirements of fuel element manufacture , the sensitivity analysis of engineering hot spot factor for multi-layer tube fuel element was completed from both aspects of fuel manufacture and reactor operation measurement .The result shows that the flow channel deviation is of direct effect on fuel element heat transfer ,yielding a higher temperature rise caused by the relevant engineering hot spot factor .

  6. Nonlinear Biochemical Signal Processing via Noise Propagation

    OpenAIRE

    Kim, Kyung Hyuk; Qian, Hong; Sauro, Herbert M.

    2013-01-01

    Single-cell studies often show significant phenotypic variability due to the stochastic nature of intra-cellular biochemical reactions. When the numbers of molecules, e.g., transcription factors and regulatory enzymes, are in low abundance, fluctuations in biochemical activities become significant and such "noise" can propagate through regulatory cascades in terms of biochemical reaction networks. Here we develop an intuitive, yet fully quantitative method for analyzing how noise affects cell...

  7. On Noise Assessment for Blended Wing Body Aircraft

    Science.gov (United States)

    Guo, Yueping; Burley, Casey L; Thomas, Russell H.

    2014-01-01

    system noise studies, which include aerodynamic performance, propulsion efficiency, flight profile limitation and many other factors. For a future aircraft concept to achieve the NASA N+2 noise goal it will require a range of fully successful noise reduction technology developments.

  8. Mediality is Noise

    DEFF Research Database (Denmark)

    Prior, Andrew

    This PhD is concerned with the use of noise as a material within media arts practice, especially in ‘post-digital’ contexts such as glitch electronica, glitch art and uses of old media. It examines the relationship between informational culture and noise, exploring the ways in which the structuring...

  9. Sounding Off about Noise

    Science.gov (United States)

    Crumpton, Michael A.

    2005-01-01

    Noise in a community college library can be part of the nature of the environment. It can also become a huge distraction for those who see the library as their sanctuary for quiet study and review of resources. This article describes the steps that should be taken by library staff in order to be proactive about noise and the library environment,…

  10. Speech communications in noise

    Science.gov (United States)

    1984-07-01

    The physical characteristics of speech, the methods of speech masking measurement, and the effects of noise on speech communication are investigated. Topics include the speech signal and intelligibility, the effects of noise on intelligibility, the articulation index, and various devices for evaluating speech systems.

  11. Development and Fielding of a Direct Methanol Fuel Cell

    Science.gov (United States)

    2010-03-01

    fuel cell to power operational test instrumentation in support of the future combat systems test and evaluation. This unit also has application by the German Bundeswehr as a battery-charging station and auxiliary power unit. The direct methanol fuel cell is characterized by its low noise emission, minimal thermal signature, and high fuel efficiency that will enable continuously sustained operation for long duration missions in the

  12. The influences of low frequency noise on mental performance

    Directory of Open Access Journals (Sweden)

    J. Hatami

    2008-01-01

    Full Text Available AbstractBackground and Purpose: Although the evolution of industrial systems toward digital technologies decreased the exposure to high levels of noise, it has created some problems encountered with low level and provoking noise (low frequency noise. In the present work, the mental performance of students exposed to low frequency and reference noises at low and high levels (45 & 65 dB were studied. Additionally, other factors such as annoyance, sensitivity to low frequency noise and hearing status of participants were considered.Materials and Methods: After generating low frequency and reference noises required for the study, a pilot study was conducted. Then, 54 students participated in the main study after preliminary tests. Their mental performances were evaluated with standard psychological tests while they were exposed to low frequency and reference noises at 45 and 65 dBA.Results: The results showed that noise annoyance and low frequency noise sensitivity do not have a significant correlation with age and sex. The results also revealed that, low frequency noise at 65 dB can decrease concentration (P=0.003 and increase response time (P=0.039 of performance in comparison with low frequency noise at 45 dB. On the other hand, reference noise at 65 dB can increase speed (P<0.001 of performance in comparison with reference noise at 45 dB.Conclusion: Low frequency noise can reduce the mental performance and increase its response time.Key words: Low Frequency Noise, Reference Noise, Noise Annoyance, Mental PerformanceJ Mazand Univ Med Sci 2008; 18(63: 55-65(Persian

  13. Noise in Coevolving Networks

    CERN Document Server

    Diakonova, Marina; Miguel, Maxi San

    2014-01-01

    Coupling dynamics of the states of the nodes of a network to the dynamics of the network topology leads to generic absorbing and fragmentation transitions. The coevolving voter model is a typical system that exhibits such transitions at some critical rewiring. We study the robustness of these transitions under two distinct ways of introducing noise. Noise affecting all the nodes destroys the absorbing-fragmentation transition, giving rise in finite-size systems to two regimes: bimodal magnetisation and dynamic fragmentation. Noise Targeting a fraction of nodes preserves the transitions but introduces shattered fragmentation with its characteristic fraction of isolated nodes and one or two giant components. Both the lack of absorbing state for homogenous noise and the shift in the absorbing transition to higher rewiring for targeted noise are supported by analytical approximations.

  14. Assessment of Noise Exposure and Noise Annoyance in a Steel Factory

    Directory of Open Access Journals (Sweden)

    Leila Ibrahimi Ghavam Abadi

    2016-09-01

    Full Text Available Background Noise pollution is one of the most important risk factors in industrial settings. This study aimed to assess noise exposure and noise-induced annoyance among workers of a steel factory. Methods This cross-sectional study was conducted on 70 healthy male participants (33 office employees and 37 production line workers in a steel plant. Results The results showed that 24.24% of employees in office areas and 54% of blue-collar workers had high noise annoyance. Also, noise levels in two parts of steel factory and percentage of responds by participants that felt highly annoyed showed a significant relationship (P < 0.05. Feeling of discomfort was a major complaint that was stated by office employees (%59 and blue-collar workers (%38. Conclusions The findings of this investigation have clearly revealed that employees in both parts of steel factory are annoyed by noise. A higher noise level resulted in higher noise annoyance in the exposed workers. The need for implementing noise conservation program was established.

  15. Polarization-induced phase noise in fiber optic Michelson interferometer with Faraday rotator mirrors

    Science.gov (United States)

    Wu, Yuefeng; Li, Fang; Zhang, Wentao; Xiao, Hao; Liu, Yuliang

    2008-11-01

    Polarization-induced phase noise in Michelson interferometer with imperfect Faraday rotator mirrors was investigated. This kind of noise generates from the rotation angle errors of Faraday rotator mirrors and external polarization perturbation. The conversion factor κ, representing the magnitude conversion ability from polarization-noise to polarization induced phase-noise, have been theoretically evaluated and experimentally investigated.

  16. Solar fuels

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, J.R.

    1978-11-17

    The paper is concerned with (1) the thermodynamic and kinetic limits for the photochemical conversion and storage of solar energy as it is received on the earth's surface, and (2) the evaluation of a number of possible photochemical reactions with particular emphasis on the production of solar hydrogen from water. Procedures for generating hydrogen fuel are considered. Topics examined include the general requirements for a fuel-generation reaction, the photochemical reaction, limits on the conversion of light energy to chemical energy, an estimate of chemical storage efficiency, and the water decomposition reaction.

  17. NASA's Aeroacoustic Tools and Methods for Analysis of Aircraft Noise

    Science.gov (United States)

    Rizzi, Stephen A.; Lopes, Leonard V.; Burley, Casey L.

    2015-01-01

    Aircraft community noise is a significant concern due to continued growth in air traffic, increasingly stringent environmental goals, and operational limitations imposed by airport authorities. The ability to quantify aircraft noise at the source and ultimately at observers is required to develop low noise aircraft designs and flight procedures. Predicting noise at the source, accounting for scattering and propagation through the atmosphere to the observer, and assessing the perception and impact on a community requires physics-based aeroacoustics tools. Along with the analyses for aero-performance, weights and fuel burn, these tools can provide the acoustic component for aircraft MDAO (Multidisciplinary Design Analysis and Optimization). Over the last decade significant progress has been made in advancing the aeroacoustic tools such that acoustic analyses can now be performed during the design process. One major and enabling advance has been the development of the system noise framework known as Aircraft NOise Prediction Program2 (ANOPP2). ANOPP2 is NASA's aeroacoustic toolset and is designed to facilitate the combination of acoustic approaches of varying fidelity for the analysis of noise from conventional and unconventional aircraft. The toolset includes a framework that integrates noise prediction and propagation methods into a unified system for use within general aircraft analysis software. This includes acoustic analyses, signal processing and interfaces that allow for the assessment of perception of noise on a community. ANOPP2's capability to incorporate medium fidelity shielding predictions and wind tunnel experiments into a design environment is presented. An assessment of noise from a conventional and Hybrid Wing Body (HWB) aircraft using medium fidelity scattering methods combined with noise measurements from a model-scale HWB recently placed in NASA's 14x22 wind tunnel are presented. The results are in the form of community noise metrics and

  18. Noise and Hearing Loss Prevention

    Science.gov (United States)

    ... visit this page: About CDC.gov . NOISE AND HEARING LOSS PREVENTION Recommend on Facebook Tweet Share Compartir Worker ... noise levels cannot be adequately reduced. Noise and Hearing Loss on the NIOSH Science Blog Read and comment ...

  19. Low-enriched fuel particle performance review. [UO2

    Energy Technology Data Exchange (ETDEWEB)

    Homan, F.; Nabielek, H.; Yang, L.

    1978-08-01

    The available data on low-enriched uranium (LEU) fuel particles were reviewed under the United States-Federal Republic of Germany Agreement. The most influential factors controlling the irradiation performance of LEU fuel particles were found to be plutonium transport, fission product transport, fuel particle mechanical performance, and fuel particle chemical performance.

  20. FET noise studies

    Science.gov (United States)

    Pucel, R. A.

    1981-03-01

    The GaAs FET oscillator is an alternative device for voltage-controlled oscillator (VCO) applications because of its inherent wide-band electronic tunability, the variety of operating modes possible such as common source, common gate, etc., and the ease of circuit design. However, it has one major drawback, namely, its high near-carrier 1/f noise which makes it unsuitable for many applications, such as radar systems. This report describes the progress made during the report period in understanding the physical mechanisms responsible for this noise. During this period, an extensive experimental study was made of the 1/f noise properties of a variety of oscillators constructed of FET chips fabricated under controlled conditions. Using in-house grown epitaxial wafers, FET's were fabricated from both buffered and unbuffered active layers, with and without epitaxially grown contact layers, and with and without surface passivation. The experimental results show a good correlation between the trap-generated 1/f baseband noise and the near-carrier 1/f FM noise. The primary sources of the noise are presumed to be either deep traps within the depletion layer under the gate or surface states at the gate-semiconductor interface, probably the latter. An improvement of the order of 10 dB in the near carrier FM noise level is obtained when a buffer layer separates the active layer from the substrate. Optical experiments indicated an electron trap level approximately 0.41 eV below the conduction band. A noise model was devised to explain the modulation process for upconverting baseband 1/f noise to the carrier band by depletion layer modulation.

  1. A design on low noise imaging circuit for SWIR sensor

    Science.gov (United States)

    Fan, Ben; Han, Zhixue; Ma, Fei; Dong, Shuli

    2016-11-01

    SWIR (Short Wave Infrared) imaging is an important imaging technology in space remote sensing. According to the characteristics of SWIR detector, the whole scheme of low noise imaging circuit is presented in this paper. For certain key circuit which noise is sensitive in the design, such as bias generation circuit, analysis of noise sources and calculation of theoretical noise value of actual circuit which is usually ignored in previous researches are proposed in order to estimate the level of circuit noise and optimize the circuit to reduce noise. The structure of analog filter amplifier circuit is also analyzed by introducing noise-factor analytic approach, based on the analysis result some design principles of the circuit are proposed. The noise suppression methods in the design are separately analyzed in both time suppression and space suppression; some specific methods for these two kinds of measures are listed in this paper. The final experiment results indicate that the low noise imaging circuit design based on above methods is reasonable and effective, the circuit has a higher SNR and can work normally at room temperature, and the whole design meets the original requirement of low noise. This low noise circuit for SWIR detector and its methods to analyze and calculate noise value are valuable examples for future similar designs.

  2. Irradiation behavior of metallic fast reactor fuels

    Energy Technology Data Exchange (ETDEWEB)

    Pahl, R.G.; Porter, D.L.; Crawford, D.C.; Walters, L.C.

    1991-01-01

    Metallic fuels were the first fuels chosen for liquid metal cooled fast reactors (LMR's). In the late 1960's world-wide interest turned toward ceramic LMR fuels before the full potential of metallic fuel was realized. However, during the 1970's the performance limitations of metallic fuel were resolved in order to achieve a high plant factor at the Argonne National Laboratory's Experimental Breeder Reactor II. The 1980's spawned renewed interest in metallic fuel when the Integral Fast Reactor (IFR) concept emerged at Argonne National Laboratory. A fuel performance demonstration program was put into place to obtain the data needed for the eventual licensing of metallic fuel. This paper will summarize the results of the irradiation program carried out since 1985.

  3. Criteria for environmental noise assessment

    OpenAIRE

    Hadzi-Nikolova, Marija; Mirakovski, Dejan; Doneva, Nikolinka

    2015-01-01

    The noise assessment generally refers to the assessment of noise impact from a specific source, such as noise originating from certain industrial plants, road traffic, and this is not always an easy task. Practically in every surrounding, a number of different sources contribute to the ambiental noise at a certain point. Standardization of noise level includes recommendations for noise level prescribed by legislation, which are enabling stay in the environment without danger to human heal...

  4. Controlled Noise Seismology

    KAUST Repository

    Hanafy, Sherif M.

    2015-08-19

    We use controlled noise seismology (CNS) to generate surface waves, where we continuously record seismic data while generating artificial noise along the profile line. To generate the CNS data we drove a vehicle around the geophone line and continuously recorded the generated noise. The recorded data set is then correlated over different time windows and the correlograms are stacked together to generate the surface waves. The virtual shot gathers reveal surface waves with moveout velocities that closely approximate those from active source shot gathers.

  5. Quantum Noise in Amplifiers and Hawking/Dumb-Hole Radiation as Amplifier Noise

    CERN Document Server

    Unruh, W G

    2011-01-01

    The quantum noise in a linear amplifier is shown to be thermal noise. The theory of linear amplifiers is applied first to the simplest, single or double oscillator model of an amplifier, and then to linear model of an amplifier with continuous fields and input and outputs. Finally it is shown that the thermal noise emitted by black holes first demonstrated by Hawking, and of dumb holes (sonic and other analogs to black holes), arises from the same analysis as for linear amplifiers. The amplifier noise of black holes acting as amplifiers on the quantum fields living in the spacetime surrounding the black hole is the radiation discovered by Hawking. For any amplifier, that quantum noise is completely characterized by the attributes of the system regarded as a classical amplifier, and arises out of those classical amplification factors and the commutation relations of quantum mechanics.

  6. Study on low-phase-noise optoelectronic oscillator and high-sensitivity phase noise measurement system.

    Science.gov (United States)

    Hong, Jun; Liu, An-min; Guo, Jian

    2013-08-01

    An analytic model for an injection-locked dual-loop optoelectronic oscillator (OEO) is proposed and verified by experiments in this paper. Based on this theoretical model, the effect of injection power on the single-sideband phase noise of the OEO is analyzed, and results suggest that moderate injection is one key factor for a balance between phase noise and spur for OEO. In order to measure superlow phase noise of OEOs, a cross-correlation measurement system based on the fiber delay line is built, in which high linear photodetector and low-phase-noise amplifier are used to improve systematic sensitivity. The cross-correlation measurement system is validated by experiments, and its noise floor for the X band is about -130 dBc/Hz at 1 kHz and -168 dBc/Hz at 10 kHz after a cross correlation of 200 times.

  7. Fuel choices in urban Indian households

    Energy Technology Data Exchange (ETDEWEB)

    Farsi, Mehdi; Filippini, Massimo [Centre for Energy Policy and Economics, Department of Management, Technology and Economics, ETH Zurich, Switzerland and Department of Economics, University of Lugano, (Switzerland); Pachauri, Shonali [International Institute for Applied Systems Analysis, Schlossplatz 1, A-2361, Laxenburg, (Austria)

    2007-12-15

    This paper applies an ordered discrete choice framework to model fuel choices and patterns of cooking fuel use in urban Indian households. The choices considered are for three main cooking fuels: firewood, kerosene, and LPG (liquid petroleum gas). The models, estimated using a large microeconomic dataset, show a reasonably good performance in the prediction of households' primary and secondary fuel choices. This suggests that ordered models can be used to analyze multiple fuel use patterns in the Indian context. The results show that lack of sufficient income is one of the main factors that retard households from using cleaner fuels, which usually also require the purchase of relatively expensive equipment. The results also indicate that households are sensitive to LPG prices. In addition to income and price, several socio-demographic factors such as education and sex of the head of the household are also found to be important in determining household fuel choice. (Author).

  8. Epidemiology of noise and legal aspects

    Directory of Open Access Journals (Sweden)

    Simone Alexandrino

    2016-12-01

    Full Text Available This article provides a brief interdisciplinary approach to the health-disease phenomenon in the workplace related to occupational noise exposure and regulatory developments involving the subject. What justifies the discussion of this theme is the constant regulatory changes in the regulation of the maximum tolerance limit for exposure to occupational noise in decibels, which despite being the result of tests carried out in accredited laboratories by the Ministry of Labor and Employment can not be effective for avoid the illness of workers. It is intended to answer the following questions: What is epidemiology and how occupational noise exposure can be a risk factor for workers; why there are so many changes in the rules governing the fixing of maximum decibels to which workers can be "safely" exposed; whether the rules governing the safety of workers exposed to occupational noise are effective in protecting the health of these people.

  9. Measuring the Noise Caused by Tehran Metro

    Directory of Open Access Journals (Sweden)

    Majid Abbas Pour

    1999-03-01

    Full Text Available One of the most common and important sources of noise in the residential environments are vehicles such as airplanes and subways. Trafficking of vehicles in streets and highways, psychologically, have damaging impacts on people living close to such areas. The development and expansion of the trading and industrial units is another factor that causes more and more exposure to noise.We have aimed at measuring the noises caused by vibration of subways of the Line of Karaj-Tehran-Mehrshahr and its effect on its surrounding area.To study this effect we designed a mathematical model and put the information of this subway line in the mentioned model. Then we analyzed the findings.This model demonstrated that we can control the harsh noise of the subway by reducing the speed of the train to 60Km/h in some points and increase in other parts to 130Km/h.

  10. Noise enhances information transfer in hierarchical networks.

    Science.gov (United States)

    Czaplicka, Agnieszka; Holyst, Janusz A; Sloot, Peter M A

    2013-01-01

    We study the influence of noise on information transmission in the form of packages shipped between nodes of hierarchical networks. Numerical simulations are performed for artificial tree networks, scale-free Ravasz-Barabási networks as well for a real network formed by email addresses of former Enron employees. Two types of noise are considered. One is related to packet dynamics and is responsible for a random part of packets paths. The second one originates from random changes in initial network topology. We find that the information transfer can be enhanced by the noise. The system possesses optimal performance when both kinds of noise are tuned to specific values, this corresponds to the Stochastic Resonance phenomenon. There is a non-trivial synergy present for both noisy components. We found also that hierarchical networks built of nodes of various degrees are more efficient in information transfer than trees with a fixed branching factor.

  11. [Effects of noise on inner ear].

    Science.gov (United States)

    Bouccara, Didier; Ferrary, Evelyne; Sterkers, Olivier

    2006-11-01

    The effects of noise on health depend both on individual factors and characteristics of sound exposure. In case of acoustic trauma, reversible or irreversible lesions of inner ear components are possible. Most often there is immediately an acute tinnitus and hearing loss. Audiometric tests demonstrate hearing loss on the high frequency, generally focused on 4 kHz. Immediate treatment is recommended even there is no currently indicator of the ability to restore hearing. New perspectives on treatment are directed to local treatment and/or using new procedure as antioxidative treatment. Occupational and leisure are the two conditions in which chronic exposure to noise is found. Detection and prevention of noise-induced hearing loss is easier in case of industrial workers than in case of noise exposition for musicians and other sounds and stage technicians or concert managers, and of course non-professional with exposure to amplified music.

  12. Shot Noise in a Mesoscopic Interferometer

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guang-Biao; WANG Shun-Jin; LI Lei

    2006-01-01

    The charge conductance and the shot noise in an Aharonov-Bohm interferometer with double quantum dots embedded and coupled to each other by a capacity are studied in the framework of the equation of motion of Green's flunction.From the impurity Anderson model Hamiltonian,the equations of motion of nonequilibrium Green functions are derived and solved including the effects of two body correlations under Lacrolx's approximation.Our results show that the conductance,the shot noise,and the Fano factor (the ratio of the shot noise to the Poisson noise)as functions of the magnetic flux oscillate with the period of h/e,and their oscillation behaviour is similar to the resuIts of the experiment replacing the capacitive coupling by tunnelling between the two dots.The experiment is suggested to test the results.

  13. Fuel Cells

    Science.gov (United States)

    Hawkins, M. D.

    1973-01-01

    Discusses the theories, construction, operation, types, and advantages of fuel cells developed by the American space programs. Indicates that the cell is an ideal small-scale power source characterized by its compactness, high efficiency, reliability, and freedom from polluting fumes. (CC)

  14. Transport fuel

    DEFF Research Database (Denmark)

    Ronsse, Frederik; Jørgensen, Henning; Schüßler, Ingmar

    2014-01-01

    Worldwide, the use of transport fuel derived from biomass increased four-fold between 2003 and 2012. Mainly based on food resources, these conventional biofuels did not achieve the expected emission savings and contributed to higher prices for food commod - ities, especially maize and oilseeds...

  15. Effect of external classroom noise on schoolchildren's reading and mathematics performance: correlation of noise levels and gender.

    Science.gov (United States)

    Papanikolaou, M; Skenteris, N; Piperakis, S M

    2015-02-01

    The present study investigated the effect of low, medium, and high traffic road noise as well as irrelevant background speech noise on primary school children's reading and mathematical performance. A total of 676 participants (324 boys, 47.9% and 352 girls, 52.1%) of the 4th and 5th elementary classes participated in the project. The participants were enrolled in public primary schools from urban areas and had ages ranging from 9 to 10 years and from. Schools were selected on the basis of increasing levels of exposure to road traffic noise and then classified into three categories (Low noise: 55-66 dB, Medium noise: 67-77 dB, and High noise: 72-80 dB). We measured reading comprehension and mathematical skills in accordance with the national guidelines for elementary education, using a test designed specifically for the purpose of this study. On the one hand, children in low-level noise schools showed statistically significant differences from children in medium- and high-level noise schools in reading performance (plevel noise schools differed significantly from children in high-level noise schools but only in mathematics performance (p=0.001). Girls in general did better in reading score than boys, especially in schools with medium- and high-level noise. Finally the levels of noise and gender were found to be two independent factors.

  16. Stochastic noise in splicing machinery.

    Science.gov (United States)

    Melamud, Eugene; Moult, John

    2009-08-01

    The number of known alternative human isoforms has been increasing steadily with the amount of available transcription data. To date, over 100 000 isoforms have been detected in EST libraries, and at least 75% of human genes have at least one alternative isoform. In this paper, we propose that most alternative splicing events are the result of noise in the splicing process. We show that the number of isoforms and their abundance can be predicted by a simple stochastic noise model that takes into account two factors: the number of introns in a gene and the expression level of a gene. The results strongly support the hypothesis that most alternative splicing is a consequence of stochastic noise in the splicing machinery, and has no functional significance. The results are also consistent with error rates tuned to ensure that an adequate level of functional product is produced and to reduce the toxic effect of accumulation of misfolding proteins. Based on simulation of sampling of virtual cDNA libraries, we estimate that error rates range from 1 to 10% depending on the number of introns and the expression level of a gene.

  17. Noise pollution in a Refining & Petrochemical Company in Nigeria.

    Directory of Open Access Journals (Sweden)

    J.O. Osarenmwinda

    2015-04-01

    Full Text Available Nowadays, the concern about noise pollution is acquiring considerable importance especiallly in industrial enviroment where there exist alot of machinerys and equipment. The aim of this study was to determine the level of noise pollution generated by some plants specifically Carbon Black Plant, Power Plant & Utilities, Waste Water treatment Plant and Fuels Plant in Warri Refining & Petrochemical Company (WRPC, Warri, Nigeria and recommmend strageties for noise control. Noise level data was obtained from the environmental monitoring unit of WRPC for period April to November, 2012 .The results showed that the noise level exceeded the 85 dB(A WHO recommended limit for industrial area in the Carbon Black Plant,Power Plant & Utilities and Fuels Plant in WRPC but was lower than 85 dB(A in Waste Water treatment Plant section of WRPC.It was observed that such noise pollution can present health problems to the workers.Recommendations have been made to the company in this study to remedy this problems and challenges.

  18. Acoustics Noise Test Cell

    Data.gov (United States)

    Federal Laboratory Consortium — The Acoustic Noise Test Cell at the NASA/Caltech Jet Propulsion Laboratory (JPL) is located adjacent to the large vibration system; both are located in a class 10K...

  19. Noise upon the Sinusoids

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer

    2005-01-01

    Sinusoids are used for making harmonic and other sounds. In order to having life in the sounds and adding a wide variety of noises, irregularities are inserted in the frequency and amplitudes. A simple and intuitive noise model is presented, consisting of a low-pass filtered noise, and having...... control for strength and bandwidth. The noise is added on the frequency and amplitudes of the sinusoids, and the resulting irregularity’s (jitter and shimmer) bandwidth is derived. This, together with an overview of investigation methods of the jitter and shimmer results in an analysis of the necessary...... samplerate of the shimmer and jitter. A harmonic model introduces individual and common irregularity, and adds a correlation control. The model has been implemented in max/msp and used in contemporary music compositions....

  20. Noise upon the sinusoids

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer

    2005-01-01

    Sinusoids are used for making harmonic and other Sounds. In order to having life in the sounds and adding a wide variety of noises, irregularities are inserted in the frequency and amplitudes. A simple and intuitive noise model is presented, consisting of a low-pass filtered noise, and having...... control for strength and bandwidth. The noise is added on the frequency and amplitudes of the sinusoids, and the resulting irregularity's (jitter and shimmer) bandwidth is derived. This, together with an overview of investigation methods of the jitter and shimmer results in an analysis of the necessary...... samplerate of the shimmer and jitter. A harmonic model introduces individual and common irregularity, and adds a correlation control. The model has been implemented in max/msp and used in contemporary Music compositions....

  1. Acoustics Noise Test Cell

    Data.gov (United States)

    Federal Laboratory Consortium — The Acoustic Noise Test Cell at the NASA/Caltech Jet Propulsion Laboratory (JPL) is located adjacent to the large vibration system; both are located in a class 10K...

  2. Conservative Noise Filters

    Directory of Open Access Journals (Sweden)

    Mona M.Jamjoom

    2016-05-01

    Full Text Available Noisy training data have a huge negative impact on machine learning algorithms. Noise-filtering algorithms have been proposed to eliminate such noisy instances. In this work, we empirically show that the most popular noise-filtering algorithms have a large False Positive (FP error rate. In other words, these noise filters mistakenly identify genuine instances as outliers and eliminate them. Therefore, we propose more conservative outlier identification criteria that improve the FP error rate and, thus, the performance of the noise filters. With the new filter, an instance is eliminated if and only if it is misclassified by a mutual decision of Naïve Bayesian (NB classifier and the original filtering criteria being used. The number of genuine instances that are incorrectly eliminated is reduced as a result, thereby improving the classification accuracy.

  3. Noise and Neuronal Heterogeneity

    CERN Document Server

    Barber, Michael J

    2010-01-01

    We consider signal transaction in a simple neuronal model featuring intrinsic noise. The presence of noise limits the precision of neural responses and impacts the quality of neural signal transduction. We assess the signal transduction quality in relation to the level of noise, and show it to be maximized by a non-zero level of noise, analogous to the stochastic resonance effect. The quality enhancement occurs for a finite range of stimuli to a single neuron; we show how to construct networks of neurons that extend the range. The range increases more rapidly with network size when we make use of heterogeneous populations of neurons with a variety of thresholds, rather than homogeneous populations of neurons all with the same threshold. The limited precision of neural responses thus can have a direct effect on the optimal network structure, with diverse functional properties of the constituent neurons supporting an economical information processing strategy that reduces the metabolic costs of handling a broad...

  4. SELECTED PROBLEMS OF PROTECTION AGAINST ROAD TRAFFIC NOISE

    Directory of Open Access Journals (Sweden)

    Władysław Gardziejczyk

    2015-11-01

    Full Text Available The paper presents factors for assessment of road traffic noise level and possible actions towards the minimization of excessive noise in the roadway neighborhood. Changes of equivalent sound level values were analyzed in relation to traffic intensity, categorization and vehicles speed. In relation to measures reducing noise level in roadway’s surroundings particular attention was given to anti-noise protections and tyre/noise reduction. Acoustic effectiveness of specific solutions was showed based on chosen examples. It was proved that when admissible noise level is slightly exceeded the need for noise barrier use may be replaced by a proper design and maintenance of road pavement or by enforcement of speed limit.

  5. Jet Engine Noise Reduction

    Science.gov (United States)

    2009-04-01

    Technology Solutions, Lockheed Martin Robert S. Carnes , M.D. NRAC Member, Battelle Memorial Institute MajGen Paul A. Fratarangelo, USMC (Ret) NRAC...Development, Acquisition) (VADM Architzel). The Naval Research Advisory Committee members (Bowes, Bowler, Carnes and Fratarangelo) have broad...Lockheed Martin ADP Boeing: Jet Engine Noise Reduction for Tactical Fighter Aircraft Mr. Tom Kaemming, K. Viswanathan, Ph . D. Tactical Jet Noise

  6. Simulation-Based Prediction of Equivalent Continuous Noises during Construction Processes.

    Science.gov (United States)

    Zhang, Hong; Pei, Yun

    2016-08-12

    Quantitative prediction of construction noise is crucial to evaluate construction plans to help make decisions to address noise levels. Considering limitations of existing methods for measuring or predicting the construction noise and particularly the equivalent continuous noise level over a period of time, this paper presents a discrete-event simulation method for predicting the construction noise in terms of equivalent continuous level. The noise-calculating models regarding synchronization, propagation and equivalent continuous level are presented. The simulation framework for modeling the noise-affected factors and calculating the equivalent continuous noise by incorporating the noise-calculating models into simulation strategy is proposed. An application study is presented to demonstrate and justify the proposed simulation method in predicting the equivalent continuous noise during construction. The study contributes to provision of a simulation methodology to quantitatively predict the equivalent continuous noise of construction by considering the relevant uncertainties, dynamics and interactions.

  7. Simulation-Based Prediction of Equivalent Continuous Noises during Construction Processes

    Directory of Open Access Journals (Sweden)

    Hong Zhang

    2016-08-01

    Full Text Available Quantitative prediction of construction noise is crucial to evaluate construction plans to help make decisions to address noise levels. Considering limitations of existing methods for measuring or predicting the construction noise and particularly the equivalent continuous noise level over a period of time, this paper presents a discrete-event simulation method for predicting the construction noise in terms of equivalent continuous level. The noise-calculating models regarding synchronization, propagation and equivalent continuous level are presented. The simulation framework for modeling the noise-affected factors and calculating the equivalent continuous noise by incorporating the noise-calculating models into simulation strategy is proposed. An application study is presented to demonstrate and justify the proposed simulation method in predicting the equivalent continuous noise during construction. The study contributes to provision of a simulation methodology to quantitatively predict the equivalent continuous noise of construction by considering the relevant uncertainties, dynamics and interactions.

  8. ICBEN review of research on the biological effects of noise 2011-2014.

    Science.gov (United States)

    Basner, Mathias; Brink, Mark; Bristow, Abigail; de Kluizenaar, Yvonne; Finegold, Lawrence; Hong, Jiyoung; Janssen, Sabine A; Klaeboe, Ronny; Leroux, Tony; Liebl, Andreas; Matsui, Toshihito; Schwela, Dieter; Sliwinska-Kowalska, Mariola; Sörqvist, Patrik

    2015-01-01

    The mandate of the International Commission on Biological Effects of Noise (ICBEN) is to promote a high level of scientific research concerning all aspects of noise-induced effects on human beings and animals. In this review, ICBEN team chairs and co-chairs summarize relevant findings, publications, developments, and policies related to the biological effects of noise, with a focus on the period 2011-2014 and for the following topics: Noise-induced hearing loss; nonauditory effects of noise; effects of noise on performance and behavior; effects of noise on sleep; community response to noise; and interactions with other agents and contextual factors. Occupational settings and transport have been identified as the most prominent sources of noise that affect health. These reviews demonstrate that noise is a prevalent and often underestimated threat for both auditory and nonauditory health and that strategies for the prevention of noise and its associated negative health consequences are needed to promote public health.

  9. Active noise control primer

    CERN Document Server

    Snyder, Scott D

    2000-01-01

    Active noise control - the reduction of noise by generating an acoustic signal that actively interferes with the noise - has become an active area of basic research and engineering applications. The aim of this book is to present all of the basic knowledge one needs for assessing how useful active noise control will be for a given problem and then to provide some guidance for designing, setting up, and tuning an active noise-control system. Written for students who have no prior knowledge of acoustics, signal processing, or noise control but who do have a reasonable grasp of basic physics and mathematics, the book is short and descriptive. It leaves for more advanced texts or research monographs all mathematical details and proofs concerning vibrations, signal processing and the like. The book can thus be used in independent study, in a classroom with laboratories, or in conjunction with a kit for experiment or demonstration. Topics covered include: basic acoustics; human perception and sound; sound intensity...

  10. Noise composed of multiplication of two dichotomous noises

    Institute of Scientific and Technical Information of China (English)

    Li Jing-Hui

    2008-01-01

    In this paper, we introduce a noise which is composed of multiplication of two dichotomous noises, and derive the probability density and the statistical properties of this noise. The obtained results can help study the resonant activation phenomenon, the phenomenon of stochastic resonance, the transport of particles, and the nonequilibrium (phase) transition for the systems driven by this noise.

  11. Improving the performance of dual fuel engines running on natural gas/LPG by using pilot fuel derived from jojoba seeds

    Energy Technology Data Exchange (ETDEWEB)

    Selim, Mohamed Y.E. [Mechanical Engineering Department, College of Engineering, UAE University, Jimmi, Al-Ain, P.O. Box 17555, Abu Dhabi (United Arab Emirates); Radwan, M.S.; Saleh, H.E. [Mechanical Power Engineering Department, Faculty of Engineering at Mattaria, Helwan University, Cairo (Egypt)

    2008-06-15

    The use of jojoba methyl ester as a pilot fuel was investigated for almost the first time as a way to improve the performance of dual fuel engine running on natural gas or liquefied petroleum gas (LPG) at part load. The dual fuel engine used was Ricardo E6 variable compression diesel engine and it used either compressed natural gas (CNG) or LPG as the main fuel and jojoba methyl ester as a pilot fuel. Diesel fuel was used as a reference fuel for the dual fuel engine results. During the experimental tests, the following have been measured: engine efficiency in terms of specific fuel consumption, brake power output, combustion noise in terms of maximum pressure rise rate and maximum pressure, exhaust emissions in terms of carbon monoxide and hydrocarbons, knocking limits in terms of maximum torque at onset of knocking, and cyclic variability data of 100 engine cycles in terms of maximum pressure and its pressure rise rate average and standard deviation. The tests examined the following engine parameters: gaseous fuel type, engine speed and load, pilot fuel injection timing, pilot fuel mass and compression ratio. Results showed that using the jojoba fuel with its improved properties has improved the dual fuel engine performance, reduced the combustion noise, extended knocking limits and reduced the cyclic variability of the combustion. (author)

  12. Quantification of airport community noise impact in terms of noise levels, population density, and human subjective response

    Science.gov (United States)

    Deloach, R.

    1981-01-01

    The Fraction Impact Method (FIM), developed by the National Research Council (NRC) for assessing the amount and physiological effect of noise, is described. Here, the number of people exposed to a given level of noise is multiplied by a weighting factor that depends on noise level. It is pointed out that the Aircraft-noise Levels and Annoyance MOdel (ALAMO), recently developed at NASA Langley Research Center, can perform the NRC fractional impact calculations for given modes of operation at any U.S. airport. The sensitivity of these calculations to errors in estimates of population, noise level, and human subjective response is discussed. It is found that a change in source noise causes a substantially smaller change in contour area than would be predicted simply on the basis of inverse square law considerations. Another finding is that the impact calculations are generally less sensitive to source noise errors than to systematic errors in population or subjective response.

  13. Design and Noise Optimization of RF Low Noise Amplifier for IEEE Standard 802.11A WLAN

    Directory of Open Access Journals (Sweden)

    Munish Kumar

    2012-05-01

    Full Text Available Low noise amplifier is the front end block of radio-frequency receiver system. Its design required various characteristics such as power gain, noise figure, insertion losses and power consumption. In this paper we have proposed a single stage low noise amplifier design with high gain and low noise using inductive source degeneration topology for frequency range of 3 GHz to 7 GHz and also use the active biasing devices. A range of devices like inductors and capacitors are used to achieve 50 Ω input impedance with a low noise factor. The design process is simulated process is using Advance Design System (ADS and implemented in TSMC 0.18 µm CMOS technology. A single stage low noise amplifier has a measured forward gain 25.4 dB and noise figure 2.2 dB at frequency 5.0 GHz.

  14. Subjective assessment of simulated helicopter blade-slap noise

    Science.gov (United States)

    Lawton, B. W.

    1976-01-01

    The effects of several characteristics of helicopter blade slap upon human annoyance are examined. Blade slap noise was simulated by using continuous and impulsive noises characterized by five parameters: The number of sine waves in a single impulse; the frequency of the sine waves; the impulse repetition frequency; the sound pressure level (SPL) of the continuous noise; and the idealized crest factor of the impulses. Ten second samples of noise were synthesized with each of the five parameters at representative levels. The annoyance of each noise was judged by 40 human subjects. Analysis of the subjective data indicated that each of the five parameters had a statistically significant effect upon the annoyance judgments. The impulse crest factor and SPL of the continuous noise had very strong positive relationships with annoyance. The other parameters had smaller, but still significant, effects upon the annoyance judgments.

  15. Cardiovascular effects of environmental noise: Research in Germany

    Directory of Open Access Journals (Sweden)

    Christian Maschke

    2011-01-01

    Full Text Available Research on systematic noise effects started in Germany back in the fifties with basic experimental studies on humans. As a result, noise was classified as a non-specific stressor, which could cause an ergotropic activation of the complete organism. In the light of this background research a hypothesis was proposed that long-term noise exposure could have an adverse effect on health. This hypothesis was further supported by animal studies. Since the sixties, the adverse effects of chronic road traffic noise exposure were further examined in humans with the help of epidemiological studies. More epidemiological aircraft noise studies followed in the 1970s and thereafter. The sample size was increased, relevant confounding factors were taken into account, and the exposure and health outcomes were investigated objectively and with higher quality measures. To date, more than 20 German epidemiological traffic noise studies have focused on noise-induced health effects, mainly on the cardiovascular system. In particular, the newer German noise studies demonstrate a clear association between residential exposure to traffic noise (particularly night noise and cardiovascular outcomes. Nevertheless, additional research is needed, particularly on vulnerable groups and multiple noise exposures. The epidemiological findings have still not been fully considered in German regulations, particularly for aircraft noise. The findings, however, were taken into account in national recommendations. The Federal Environment Agency recommends noise rating levels of 65 dB(A for the day and 55 dB(A for the night, as a short-term goal. In the medium term, noise rating levels of 60 / 50 (day, night should be reached and noise rating levels of 55 / 45 in the long run.

  16. Solid oxide fuel cell anode image segmentation based on a novel quantum-inspired fuzzy clustering

    Science.gov (United States)

    Fu, Xiaowei; Xiang, Yuhan; Chen, Li; Xu, Xin; Li, Xi

    2015-12-01

    High quality microstructure modeling can optimize the design of fuel cells. For three-phase accurate identification of Solid Oxide Fuel Cell (SOFC) microstructure, this paper proposes a novel image segmentation method on YSZ/Ni anode Optical Microscopic (OM) images. According to Quantum Signal Processing (QSP), the proposed approach exploits a quantum-inspired adaptive fuzziness factor to adaptively estimate the energy function in the fuzzy system based on Markov Random Filed (MRF). Before defuzzification, a quantum-inspired probability distribution based on distance and gray correction is proposed, which can adaptively adjust the inaccurate probability estimation of uncertain points caused by noises and edge points. In this study, the proposed method improves accuracy and effectiveness of three-phase identification on the micro-investigation. It provides firm foundation to investigate the microstructural evolution and its related properties.

  17. Community response to tramway noise

    NARCIS (Netherlands)

    Miedema, H.M.E.; Berg, R. van den

    1988-01-01

    A study concerning tramway noise is described and results are presented. The study consisted of a social survey and a noise measurement program. It appeared that tramway noise does not contribute to the annoyance of the total noise if tramway annoyance is substantially below road traffic annoyance

  18. Community response to tramway noise

    NARCIS (Netherlands)

    Miedema, H.M.E.; Berg, R. van den

    1988-01-01

    A study concerning tramway noise is described and results are presented. The study consisted of a social survey and a noise measurement program. It appeared that tramway noise does not contribute to the annoyance of the total noise if tramway annoyance is substantially below road traffic annoyance (

  19. An investigation of community noise in high-rise residential environments.

    Science.gov (United States)

    Alam, Sheikh Mahbub; Eang, Lee Siew; Tan, Alan; Tiong, Tan Sze

    2010-06-01

    High-rise dwellers in Singapore are often subjected to several community noise sources in close proximity. These include food center, children playground, soccer playground, basketball playground, waste disposal truck, etc. A scientific and reliable approach is required for evaluation of the community noise and its impact on high-rise dwellers. A comprehensive noise survey by a cluster sampling technique, conducted among 522 households in five residential towns in Singapore, showed that community noise was one of the prime sources of noise in a high-rise residential environment. From a subjective noise survey, undertaken concurrent with objective noise measurements, a mean outdoor noise level of 59 dBA was established as an acceptable noise level in the indoor environment. To investigate the level of noise exposure from different community noise sources, software modeling and simulations were carried out. The predicted results were validated with field measured data at five 16 story residential buildings. Analysis of noise exposure data showed that except for waste disposal truck, noise exposure due to other community noise sources (building distance of 15 m) were within the established acceptable noise level. A factor analysis of the survey data identified the key factors related to the disturbance due to community noise sources.

  20. Measurement of Acceptable Noise Level with Background Music

    OpenAIRE

    Ahn, Hyun-Jung; Bahng, Junghwa; Lee, Jae Hee

    2015-01-01

    Background and Objectives Acceptable noise level (ANL) is a measure of the maximum background noise level (BNL) that a person is willing to tolerate while following a target story. Although researchers have used various sources of target sound in ANL measures, a limited type of background noise has been used. Extending the previous study of Gordon-Hickey & Moore (2007), the current study determined the effect of music genre and tempo on ANLs as possible factors affecting ANLs. We also investi...

  1. Fouling in your own nest: vessel noise increases biofouling.

    Science.gov (United States)

    Stanley, Jenni A; Wilkens, Serena L; Jeffs, Andrew G

    2014-01-01

    Globally billions of dollars are spent each year on attempting to reduce marine biofouling on commercial vessels, largely because it results in higher fuel costs due to increased hydrodynamic drag. Biofouling has been long assumed to be primarily due to the availability of vacant space on the surface of the hull. Here, it is shown that the addition of the noise emitted through a vessel's hull in port increases the settlement and growth of biofouling organisms within four weeks of clean surfaces being placed in the sea. More than twice as many bryozoans, oysters, calcareous tube worms and barnacles settled and established on surfaces with vessel noise compared to those without. Likewise, individuals from three species grew significantly larger in size in the presence of vessel noise. The results demonstrate that vessel noise in port is promoting biofouling on hulls and that underwater sound plays a much wider ecological role in the marine environment than was previously considered possible.

  2. Fuel control system for dual fuel engines

    Energy Technology Data Exchange (ETDEWEB)

    Helmich, M.J.; Ryan, W.P.; Marvin, D.H.

    1987-11-24

    A fuel governing system for an engine adapted for operation on a first fuel and a second fuel is described comprising: a first fuel governing system including a spontaneous motion metering means; and a second fuel governing system, the second fuel governing system further comprising: means for providing a first signal indicative of position of the first fuel metering means, which signal approximates total load on the engine, means for providing a second signal of the selected percentage of first fuel relative to total load, means for controlling flow of the second fuel to the engine, which flow causes reflective displacement of the first fuel metering means, means for determining the difference between the first signal and the second signal, which difference is indicative of distance the first fuel metering means must be moved to attain the selected percentage of first fuel relative to total load, and means for causing operation of the means for controlling flow of the second fuel to the engine to cause displacement of the first fuel metering means equal to the distance the first fuel metering means must be moved to attain the selected percentage of first fuel relative to total load.

  3. Study of fuel cell and gas turbine hybrid power systems

    OpenAIRE

    Basurto, M. T.

    2002-01-01

    Environmental awareness and the interest in distributed generation caused by electricity market de-regulation are factors that promote research on renewable energies. Fuel cells transform the chemical energy stored in fuel into electricity by means of electrochemical reactions. Among the different fuel cell types, high temperature fuel cells (HTFCS) have many advantages: high efficiency, low emissions, fuel flexibility, modularity and high quality waste heat. The main disadvant...

  4. Solid Acid Fuel Cell Stack for APU Applications

    Energy Technology Data Exchange (ETDEWEB)

    Duong, Hau H. [SAFCell, Inc., Pasadena, CA (United States)

    2011-04-15

    Solid acid fuel cell technology affords the opportunity to operate at the 200-300 degree centigrade regime that would allow for more fuel flexibility, compared to polymer electrode membrane fuel cell, while avoiding the relatively more expensive and complex system components required by solid oxide fuel cell. This project addresses many factors such as MEA size scalability, fuel robustness, stability, etc., that are essential for successful commercialization of the technology.

  5. Nonlinear biochemical signal processing via noise propagation.

    Science.gov (United States)

    Kim, Kyung Hyuk; Qian, Hong; Sauro, Herbert M

    2013-10-14

    Single-cell studies often show significant phenotypic variability due to the stochastic nature of intra-cellular biochemical reactions. When the numbers of molecules, e.g., transcription factors and regulatory enzymes, are in low abundance, fluctuations in biochemical activities become significant and such "noise" can propagate through regulatory cascades in terms of biochemical reaction networks. Here we develop an intuitive, yet fully quantitative method for analyzing how noise affects cellular phenotypes based on identifying a system's nonlinearities and noise propagations. We observe that such noise can simultaneously enhance sensitivities in one behavioral region while reducing sensitivities in another. Employing this novel phenomenon we designed three biochemical signal processing modules: (a) A gene regulatory network that acts as a concentration detector with both enhanced amplitude and sensitivity. (b) A non-cooperative positive feedback system, with a graded dose-response in the deterministic case, that serves as a bistable switch due to noise-induced ultra-sensitivity. (c) A noise-induced linear amplifier for gene regulation that requires no feedback. The methods developed in the present work allow one to understand and engineer nonlinear biochemical signal processors based on fluctuation-induced phenotypes.

  6. Noise exposure assessment with task-based measurement in complex noise environment

    Institute of Scientific and Technical Information of China (English)

    LI Nan; YANG Qiu-ling; ZENG Lin; ZHU Liang-liang; TAO Li-yuan; ZHANG Hua; ZHAO Yi-ming

    2011-01-01

    Background Task-based measurement (TBM) is a method to assess the eight-hour A-weighted equivalent noise exposure level (LAeq. 8h) besides dosimeter. TBM can be better used in factories by non-professional workers and staffs.However, it is still not clear if TBM is equal or similar with dosimeter for LAeq.8h measurement in general. This study considered the measurement with dosimeter as real personal noise exposure level (PNEL) and assessed the accuracy of TBM by comparing the consistencies of TBM and dosimeter in LAeq.8h measurement.Methods The study was conducted in one automobile firm among 387 workers who are exposed to unstable noise.Dosimeters and TBM were used to compare the two strategies and assess the degree of agreement and causes of disagreement. Worker's PNEL was measured via TBM for noise; the real PNEL was also recorded. The TBM for noise was computed with task/position noise levels measured via sound level meter and workers' exposure information collected via working diary forms (WDF) filled by participants themselves. Full-shift noise exposure measurement via personal noise dosimeters were taken as the real PNEL. General linear model (GLM) was built to analyze the accuracy of TBM for noise and the source of difference between TBM for noise and real PNEL.Results The LAeq.8h with TBM were slightly higher than the real PNELs, except the electricians. Differences of the two values had statistical significance in stamping workers (P <0.001), assembly workers (P=0.015) and welding workers (P=0.001). The correlation coefficient of LAeq.8h with TBM and real PNELs was 0.841. Differences of the two results were mainly affected by real PNEL (F=11.27, P=0.001); and work groups (F=3.11, P <0.001) divided by jobs and workshops were also independent factors. PNEL of workers with fixed task/position ((86.53±8.82) dB(A)) was higher than those without ((75.76±9.92) dB(A)) (t=8.84, P <0.01). Whether workers had fixed task/position was another factor on the

  7. Noise and Function

    CERN Document Server

    Weinstein, Steven

    2016-01-01

    Noise is widely understood to be something that interferes with a signal or process. Thus, it is generally thought to be destructive, obscuring signals and interfering with function. However, early in the 20th century, mechanical engineers found that mechanisms inducing additional vibration in mechanical systems could prevent sticking and hysteresis. This so-called "dither" noise was later introduced in an entirely different context at the advent of digital information transmission and recording in the early 1960s. Ironically, the addition of noise allows one to preserve information that would otherwise be lost when the signal or image is digitized. As we shall see, the benefits of added noise in these contexts are closely related to the phenomenon which has come to be known as stochastic resonance, the original version of which appealed to noise to explain how small periodic fluctuations in the eccentricity of the earth's orbit might be amplified in such a way as to bring about the observed periodic transiti...

  8. Optimization of fuel rod enrichment distribution for BWR fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Yasushi; Hida, Kazuki; Sakurada, Koichi; Yamamoto, Munenari [Toshiba Corp., Kawasaki, Kanagawa (Japan). Nuclear Engineering Lab.

    1996-09-01

    A practical method was developed for determining the optimum fuel enrichment distribution within a boiling water reactor fuel assembly. The method deals with two different optimization problems, i.e. the combinatorial optimization problem of grouping fuel rods into a given number of rod groups with the same enrichment, and the problem of determining an optimal enrichment for each fuel rod under the resultant rod-grouping pattern. In solving these problems, the primary goal is to minimize a predefined objective function over a given exposure period. The objective function used here is defined by the linear combination C{sub 1}X + C{sub 2}X{sub G}, where X and X{sub G} stand, respectively, for control variables giving constraint to the local power peaking factor and the gadolinium rod power. C{sub 1} and C{sub 2} are user-definable weighting factors to accommodate design preferences. The algorithm for solving this combinatorial optimization problem starts by finding the optimal enrichment vector without any rod-grouping, and promising candidates of rod-grouping patterns are found by exhaustive enumeration based on the resulting fuel enrichment ordering. This latter problem is solved using the method of approximation programming. A practical application is shown for a contemporary 8 x 8 Pu mixed-oxide fuel assembly with 10 gadolinium-poisoned rods. (author)

  9. Noise performance of frequency modulation Kelvin force microscopy

    Directory of Open Access Journals (Sweden)

    Heinrich Diesinger

    2014-01-01

    Full Text Available Noise performance of a phase-locked loop (PLL based frequency modulation Kelvin force microscope (FM-KFM is assessed. Noise propagation is modeled step by step throughout the setup using both exact closed loop noise gains and an approximation known as “noise gain” from operational amplifier (OpAmp design that offers the advantage of decoupling the noise performance study from considerations of stability and ideal loop response. The bandwidth can be chosen depending on how much noise is acceptable and it is shown that stability is not an issue up to a limit that will be discussed. With thermal and detector noise as the only sources, both approaches yield PLL frequency noise expressions equal to the theoretical value for self-oscillating circuits and in agreement with measurement, demonstrating that the PLL components neither modify nor contribute noise. Kelvin output noise is then investigated by modeling the surrounding bias feedback loop. A design rule is proposed that allows choosing the AC modulation frequency for optimized sharing of the PLL bandwidth between Kelvin and topography loops. A crossover criterion determines as a function of bandwidth, temperature and probe parameters whether thermal or detector noise is the dominating noise source. Probe merit factors for both cases are then established, suggesting how to tackle noise performance by probe design. Typical merit factors of common probe types are compared. This comprehensive study is an encouraging step toward a more integral performance assessment and a remedy against focusing on single aspects and optimizing around randomly chosen key values.

  10. Road Traffic Noise

    Science.gov (United States)

    Beckenbauer, Thomas

    Road traffic is the most interfering noise source in developed countries. According to a publication of the European Union (EU) at the end of the twentieth century [1], about 40% of the population in 15 EU member states is exposed to road traffic noise at mean levels exceeding 55 dB(A). Nearly 80 million people, 20% of the population, are exposed to levels exceeding 65 dB(A) during daytime and more than 30% of the population is exposed to levels exceeding 55 dB(A) during night time. Such high noise levels cause health risks and social disorders (aggressiveness, protest, and helplessness), interference of communication and disturbance of sleep; the long- and short-term consequences cause adverse cardiovascular effects, detrimental hormonal responses (stress hormones), and possible disturbance of the human metabolism (nutrition) and the immune system. Even performance at work and school could be impaired.

  11. Noise and Tinnitus

    Directory of Open Access Journals (Sweden)

    Mansoureh Adel Ghahraman

    1999-03-01

    Full Text Available Tinnitus from the Latin word tinnire meaning ringing is the perception of sound within the human ear in the absence of corresponding external sound. The most common cause is noise induced hearing loss. Tinnitus may be induced by an acoustic trauma or a permanent noise in the workplace. In case that Tinnitus is induced by acoustic trauma the site of lesion is commonly the base of the cochlea. Tinnitus in the senile population is mostly accompanying presbycusis. Although the incidence of permanent tinnitus following noise exposure is high, little is published about this issue. In the current article we are aimed at studying the prevalence of tinnitus in Minoo and other manufactures.

  12. ECG De-noising

    DEFF Research Database (Denmark)

    Kærgaard, Kevin; Jensen, Søren Hjøllund; Puthusserypady, Sadasivan

    2015-01-01

    Electrocardiogram (ECG) is a widely used noninvasive method to study the rhythmic activity of the heart and thereby to detect the abnormalities. However, these signals are often obscured by artifacts from various sources and minimization of these artifacts are of paramount important. This paper...... proposes two adaptive techniques, namely the EEMD-BLMS (Ensemble Empirical Mode Decomposition in conjunction with the Block Least Mean Square algorithm) and DWT-NN (Discrete Wavelet Transform followed by Neural Network) methods in minimizing the artifacts from recorded ECG signals, and compares...... their performance. These methods were first compared on two types of simulated noise corrupted ECG signals: Type-I (desired ECG+noise frequencies outside the ECG frequency band) and Type-II (ECG+noise frequencies both inside and outside the ECG frequency band). Subsequently, they were tested on real ECG recordings...

  13. High Octane Fuel: Terminal Backgrounder

    Energy Technology Data Exchange (ETDEWEB)

    Moriarty, Kristi [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-02-11

    The Bioenergy Technologies Office of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy sponsored a scoping study to assess the potential of ethanol-based high octane fuel (HOF) to reduce energy consumption and greenhouse gas emissions. When the HOF blend is made with 25%-40% ethanol by volume, this energy efficiency improvement is potentially sufficient to offset the reduced vehicle range often associated with the decreased volumetric energy density of ethanol. The purpose of this study is to assess the ability of the fuel supply chain to accommodate more ethanol at fuel terminals. Fuel terminals are midstream in the transportation fuel supply chain and serve to store and distribute fuels to end users. While there are no technical issues to storing more ethanol at fuel terminals, there are several factors that could impact the ability to deploy more ethanol. The most significant of these issues include the availability of land to add more infrastructure and accommodate more truck traffic for ethanol deliveries as well as a lengthy permitting process to erect more tanks.

  14. Noise Source Location Optimization

    Directory of Open Access Journals (Sweden)

    Ed O’Keefe

    1994-01-01

    Full Text Available This article describes a method to determine locations of noise sources that minimize modal coupling in complex acoustic volumes. Using the acoustic source scattering capabilities of the boundary element method, predictions are made of mode shape and pressure levels due to various source locations. Combining knowledge of the pressure field with a multivariable function minimization technique, the source location generating minimum pressure levels can be determined. The analysis also allows for an objective comparison of “best/worst” locations. The technique was implemented on a personal computer for the U.S. Space Station, predicting 5–10 dB noise reduction using optimum source locations.

  15. Community response to noise.

    Science.gov (United States)

    Yano, Takashi; Gjestland, Truls; Lee, Soogab

    2012-01-01

    Activities from 2008 to 2011 by ICBEN community response to noise team were summarized. That is, individual community-based indexes such as community tolerance Level, Zuricher Fluglarm Index (ZFI) and Frankfurter Fluglarm Index (FFI/FNI) were newly proposed, differences in railway bonus between Europe and Asia were discussed by a Swedish survey, socio-acoustic surveys were reported from developing countries, and annoyance equivalents and dominant source models were proposed as the adequate combined noise model. Furthermore, not only negative, but also positive aspects of sound were discussed as soundscape studies. Finally, seven items were listed as future team activities.

  16. Community response to noise

    Directory of Open Access Journals (Sweden)

    Takashi Yano

    2012-01-01

    Full Text Available Activities from 2008 to 2011 by ICBEN community response to noise team were summarized. That is, individual community-based indexes such as community tolerance Level, Zuricher Fluglarm Index (ZFI and Frankfurter Fluglarm Index (FFI/FNI were newly proposed, differences in railway bonus between Europe and Asia were discussed by a Swedish survey, socio-acoustic surveys were reported from developing countries, and annoyance equivalents and dominant source models were proposed as the adequate combined noise model. Furthermore, not only negative, but also positive aspects of sound were discussed as soundscape studies. Finally, seven items were listed as future team activities.

  17. Noise and Hearing Loss: A Review

    Science.gov (United States)

    Daniel, Eileen

    2007-01-01

    Background: Noise-induced hearing loss is a major cause of deafness and hearing impairment in the United States. Though genetics and advanced age are major risk factors, temporary and permanent hearing impairments are becoming more common among young adults and children especially with the increased exposure to portable music players. Though…

  18. 航天电子设备多余物检测信号特性的影响因素分析%Factors affecting characteristics of acoustic signals in particle impact noise detection for aerospace devices

    Institute of Scientific and Technical Information of China (English)

    陈金豹; 翟国富; 王淑娟; 刘泳; 王洪元

    2013-01-01

    According to the mechanism of sound generation and the method of spectral analysis, the influences of the operation variables and particle physical parameters on acoustic spectrum are investigated systematically in the particle impact noise detection (PIND) for aerospace devices. The particle size, physical property, acceleration and frequency of vibration conditions are considered as four factors affecting acoustic signals, and the effect laws of them are presented. The physical property is determined as the key factor, and the feasibility of particle size and material identification is confirmed using the orthogonal test method. The results are of great value for identification of particles.%依据微粒碰撞产生声波的机理,运用频谱分析法,系统地研究航天电子设备多余物噪声检测过程中各操作变量和微粒物理参数对声波频谱的影响.通过单因素试验,详细分析了微粒粒径、微粒材质属性、振动力学条件中加速度和频率等4个因素对声音信号频谱分布的影响规律.同时,采用正交试验法确定了关键影响因素为微粒材质属性,并提出了微粒材质和粒径识别的可行性.该结果为进一步识别多余物微粒的参数提供了指导依据.

  19. New opportunities for aircraft noise policy in the Netherlands

    NARCIS (Netherlands)

    Kroesen, M.

    2010-01-01

    This papers aims (1) to provide a review of the (non-acoustic) social-psychological determinants of aircraft noise annoyance, (2) evaluate Schiphol’s noise policy from a social-psychological perspective and (3) review a governance model that can effectively address non-acoustic factors in aircraft n

  20. The Effects of Syntactic Complexity on Processing Sentences in Noise

    Science.gov (United States)

    Carroll, Rebecca; Ruigendijk, Esther

    2013-01-01

    This paper discusses the influence of stationary (non-fluctuating) noise on processing and understanding of sentences, which vary in their syntactic complexity (with the factors canonicity, embedding, ambiguity). It presents data from two RT-studies with 44 participants testing processing of German sentences in silence and in noise. Results show a…

  1. Seismic exploration noise reduction in the Marginal Ice Zone.

    Science.gov (United States)

    Tollefsen, Dag; Sagen, Hanne

    2014-07-01

    A sonobuoy field was deployed in the Marginal Ice Zone of the Fram Strait in June 2011 to study the spatial variability of ambient noise. High noise levels observed at 10-200 Hz are attributed to distant (1400 km range) seismic exploration. The noise levels decreased with range into the ice cover; the reduction is fitted by a spreading loss model with a frequency-dependent attenuation factor less than for under-ice interior Arctic propagation. Numerical modeling predicts transmission loss of the same order as the observed noise level reduction and indicates a significant loss contribution from under-ice interaction.

  2. Aviation fuels outlook

    Science.gov (United States)

    Momenthy, A. M.

    1980-01-01

    Options for satisfying the future demand for commercial jet fuels are analyzed. It is concluded that the most effective means to this end are to attract more refiners to the jet fuel market and encourage development of processes to convert oil shale and coal to transportation fuels. Furthermore, changing the U.S. refineries fuel specification would not significantly alter jet fuel availability.

  3. Psychoacoustic study on contribution of fan noise to engine noise

    Science.gov (United States)

    Zhang, Junhong; Liu, Hai; Bi, Fengrong; Ni, Guangjian; Zhang, Guichang; Lin, Jiewei; Yu, Hanzhengnan

    2012-07-01

    There are more researches on engine fan noise control focusing on reducing fan noise level through optimizing fan structure, and a lot of research achievements have been obtained. However, researches on the effect of fan noise to engine noise quality are lacking. The influences of the effects of fan structure optimization on the engine noise quality are unclear. Thus, there will be a decline in fan noise level, but the deterioration of engine noise quality. Aiming at the above problems, in consideration of fan structure design and engine noise quality, an innovative method to analyze the contribution of fan noise to engine noise quality using psychoacoustic theory is proposed. The noises of diesel engine installing different cooling fans are measured by using the acoustic pressure method. The experiment results are regarded as analysis samples. The model of sensory pleasantness is used to analyze the sound quality of a diesel engine with different cooling fans. Results show that after installing 10-blade fan in medium diameter the sensory pleasantness at each test point is increased, and the increase is 13.53% on average, which indicate the improvement of the engine noise quality. In order to verify the psychoacoustical analysis, the subjective assessment is carried out. The test result shows the noise quality of engine installed 10-blade fan in medium diameter is most superior. 1/3 octave frequency spectrum analysis is used to study the reason of the improvement of engine noise quality. It is found that after installing proper cooling fan the sound pressure level below 400 Hz are obviously increased, the frequency assignment and spectral envelope are more reasonable and a proper cooling fan can optimize the spectrum structure of the engine noise. The psychoacoustic study is applied in the contribution of fan noise to engine noise, and the idea of engine sound quality improvement through the structure optimization is proposed.

  4. Noise sources and noise suppression in CMOS imagers

    Science.gov (United States)

    Pain, Bedabrata; Cunningham, Thomas J.; Hancock, Bruce R.

    2004-01-01

    Mechanisms for noise coupling in CMOS imagers are complex, since unlike a CCD, a CMOS imager has to be considered as a full digital-system-on-a-chip, with a highly sensitive front-end. In this paper, we analyze the noise sources in a photodiode CMOS imager, and model their propagation through the signal chain to determine the nature and magnitude of noise coupling. We present methods for reduction of noise, and present measured data to show their viability. For temporal read noise reduction, we present pixel signal chain design techniques to achieve near 2 electrons read noise. We model the front-end reset noise both for conventional photodiode and CTIA type of pixels. For the suppression of reset noise, we present a column feedback-reset method to reduce reset noise below 6 electrons. For spatial noise reduction, we present the design of column signal chain that suppresses both spatial noise and power supply coupling noise. We conclude by identifying problems in low-noise design caused by dark current spatial distribution.

  5. Stabilizing platinum in phosphoric acid fuel cells

    Science.gov (United States)

    Remick, R. J.

    1982-01-01

    Platinum sintering on phosphoric acid fuel cell cathodes is discussed. The cathode of the phosphoric acid fuel cell uses a high surface area platinum catalyst dispersed on a conductive carbon support to minimize both cathode polarization and fabrication costs. During operation, however, the active surface area of these electrodes decreases, which in turn leads to decreased cell performance. This loss of active surface area is a major factor in the degradation of fuel cell performance over time.

  6. Analysis of environmental factors impacting the life cycle cost analysis of conventional and fuel cell/battery-powered passenger vehicles. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-01-31

    This report presents the results of the further developments and testing of the Life Cycle Cost (LCC) Model previously developed by Engineering Systems Management, Inc. (ESM) on behalf of the U.S. Department of Energy (DOE) under contract No. DE-AC02-91CH10491. The Model incorporates specific analytical relationships and cost/performance data relevant to internal combustion engine (ICE) powered vehicles, battery powered electric vehicles (BPEVs), and fuel cell/battery-powered electric vehicles (FCEVs).

  7. Flicker (1/f) noise in tunnel junction DC SQUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Koch, R.H.; Clarke, J.; Goubau, W.M.; Martinis, J.M.; Pegrum, C.M.; Van Harlingen, D.J.

    1983-04-01

    We have measured the spectral density of the 1/f voltage noise in current-biased resistively shunted Josephson tunnel junctions and dc SQUIDs. A theory in which fluctuations in the temperature give rise to fluctuations in the critical current and hence in the voltage predicts the magnitude of the noise quite accurately for junctions with areas of about 2 x 10/sup 4/ ..mu..m/sup 2/, but significantly overestimates the noise for junctions with areas of about 6 ..mu..m/sup 2/. DC SQUIDs fabricated from these two types of junctions exhibit substantially more 1/f voltage noise than would be predicted from a model in which the noise arises from critical current fluctuations in the junctions. This result was confirmed by an experiment involving two different bias current and flux modulation schemes, which demonstrated that the predominant 1/f voltage noise arises not from critical current fluctuations, but from some unknown source that can be regarded as an apparent 1/f flux noise. Measurements on five different configurations of dc SQUIDs fabricated with thin-film tunnel junctions and with widely varying areas, inductances, and junction capacitances show that the spectral density of the 1/f equivalent flux noise is roughtly constant, within a factor of three of (10/sup -10//f)phi/sup 2//sub 0/Hz/sup -1/. It is emphasized that 1/f flux noise may not be the predominant source of 1/f noise in SQUIDS fabricated with other technologies.

  8. A Goldilocks principle for modelling radial velocity noise

    Science.gov (United States)

    Feng, F.; Tuomi, M.; Jones, H. R. A.; Butler, R. P.; Vogt, S.

    2016-09-01

    The Doppler measurements of stars are diluted and distorted by stellar activity noise. Different choices of noise models and statistical methods have led to much controversy in the confirmation of exoplanet candidates obtained through analysing radial velocity data. To quantify the limitation of various models and methods, we compare different noise models and signal detection criteria for various simulated and real data sets in the Bayesian framework. According to our analyses, the white noise model tend to interpret noise as signal, leading to false positives. On the other hand, the red noise models are likely to interpret signal as noise, resulting in false negatives. We find that the Bayesian information criterion combined with a Bayes factor threshold of 150 can efficiently rule out false positives and confirm true detections. We further propose a Goldilocks principle aimed at modelling radial velocity noise to avoid too many false positives and too many false negatives. We propose that the noise model with RHK-dependent jitter is used in combination with the moving average model to detect planetary signals for M dwarfs. Our work may also shed light on the noise modelling for hotter stars, and provide a valid approach for finding similar principles in other disciplines.

  9. Curing the noise epidemic

    Science.gov (United States)

    Mazer, Susan

    2005-09-01

    The argument is made that design does not stop when the fixed architectural and acoustical components are in place. Spaces live and breathe with the people who reside in them. Research and examples are presented that show that noise, auditory clutter, thrives on itself in hospitals. Application of the Lombard reflex studies fit into the hospital setting, but do not offer solutions as to how one might reduce the impact. In addition, the basis for looking at the noise component as a physical as well cultural dynamic will be addressed. Whether the result of the wrong conversation in the wrong place or the right conversation in an unfortunate place, talk mixed with sounds of technology is shown to cause its own symptoms. From heightened anxiety and stress to medical errors, staff burnout, or HIPAA violations, the case is made that noise is pandemic in hospitals and demands financial and operational investment. An explanation of how to reduce noise by design of the dynamic environment - equipment, technology, staff protocols is also provided.

  10. The Role that Natural Environment Plays in Reducing Noise Pollution

    Directory of Open Access Journals (Sweden)

    Nasim Saber Maash

    1999-03-01

    Full Text Available Noise pollution is one of the major problems for the present time and it can affect the life of human being. Noise pollution is excessive, displeasing human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life. Researchers have mentioned a lot of devastating effects of noise that can disrupt the physical and psychological health of human beings. Noise pollution has also been considered as an important issue which needs to be solved in industrial countries and also as a main factor that is required to be minimized in factory construction and also in producing machinery. In the current article we are aimed at discussing some solutions that natural environment can bring to mankind regarding the reduction of noise pollution.

  11. Fuel performance annual report for 1991. Volume 9

    Energy Technology Data Exchange (ETDEWEB)

    Painter, C.L.; Alvis, J.M.; Beyer, C.E. [Pacific Northwest Lab., Richland, WA (United States); Marion, A.L. [Oregon State Univ., Corvallis, OR (United States). Dept. of Nuclear Engineering; Payne, G.A. [Northwest Coll. and Univ. Association for Science, Richland, WA (United States); Kendrick, E.D. [Nuclear Regulatory Commission, Washington, DC (United States)

    1994-08-01

    This report is the fourteenth in a series that provides a compilation of information regarding commercial nuclear fuel performance. The series of annual reports were developed as a result of interest expressed by the public, advising bodies, and the US Nuclear Regulatory Commission (NRC) for public availability of information pertaining to commercial nuclear fuel performance. During 1991, the nuclear industry`s focus regarding fuel continued to be on extending burnup while maintaining fuel rod reliability. Utilities realize that high-burnup fuel reduces the amount of generated spent fuel, reduces fuel costs, reduces operational and maintenance costs, and improves plant capacity factors by extending operating cycles. Brief summaries of fuel operating experience, fuel design changes, fuel surveillance programs, high-burnup experience, problem areas, and items of general significance are provided.

  12. Tandem Cylinder Noise Predictions

    Science.gov (United States)

    Lockhard, David P.; Khorrami, Mehdi R.; CHoudhari, Meelan M.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

    2007-01-01

    In an effort to better understand landing-gear noise sources, we have been examining a simplified configuration that still maintains some of the salient features of landing-gear flow fields. In particular, tandem cylinders have been studied because they model a variety of component level interactions. The present effort is directed at the case of two identical cylinders spatially separated in the streamwise direction by 3.7 diameters. Experimental measurements from the Basic Aerodynamic Research Tunnel (BART) and Quiet Flow Facility (QFF) at NASA Langley Research Center (LaRC) have provided steady surface pressures, detailed off-surface measurements of the flow field using Particle Image Velocimetry (PIV), hot-wire measurements in the wake of the rear cylinder, unsteady surface pressure data, and the radiated noise. The experiments were conducted at a Reynolds number of 166 105 based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent shedding process and simulate the effects of a high Reynolds number flow. The parallel computational effort uses the three-dimensional Navier-Stokes solver CFL3D with a hybrid, zonal turbulence model that turns off the turbulence production term everywhere except in a narrow ring surrounding solid surfaces. The current calculations further explore the influence of the grid resolution and spanwise extent on the flow and associated radiated noise. Extensive comparisons with the experimental data are used to assess the ability of the computations to simulate the details of the flow. The results show that the pressure fluctuations on the upstream cylinder, caused by vortex shedding, are smaller than those generated on the downstream cylinder by wake interaction. Consequently, the downstream cylinder dominates the noise radiation, producing an overall directivity pattern that is similar to that of an isolated cylinder. Only calculations based on the full length of the model span were able to

  13. Reduction of turbomachinery noise

    Science.gov (United States)

    Waitz, Ian A. (Inventor); Brookfield, John M. (Inventor); Sell, Julian (Inventor); Hayden, Belva J. (Inventor); Ingard, K. Uno (Inventor)

    1999-01-01

    In the invention, propagating broad band and tonal acoustic components of noise characteristic of interaction of a turbomachine blade wake, produced by a turbomachine blade as the blade rotates, with a turbomachine component downstream of the rotating blade, are reduced. This is accomplished by injection of fluid into the blade wake through a port in the rotor blade. The mass flow rate of the fluid injected into the blade wake is selected to reduce the momentum deficit of the wake to correspondingly increase the time-mean velocity of the wake and decrease the turbulent velocity fluctuations of the wake. With this fluid injection, reduction of both propagating broad band and tonal acoustic components of noise produced by interaction of the blade wake with a turbomachine component downstream of the rotating blade is achieved. In a further noise reduction technique, boundary layer fluid is suctioned into the turbomachine blade through a suction port on the side of the blade that is characterized as the relatively low-pressure blade side. As with the fluid injection technique, the mass flow rate of the fluid suctioned into the blade is here selected to reduce the momentum deficit of the wake to correspondingly increase the time-mean velocity of the wake and decrease the turbulent velocity fluctuations of the wake; reduction of both propagating broad band and tonal acoustic components of noise produced by interaction of the blade wake with a turbomachine component downstream of the rotating blade is achieved with this suction technique. Blowing and suction techniques are also provided in the invention for reducing noise associated with the wake produced by fluid flow around a stationary blade upstream of a rotating turbomachine.

  14. Fuel lattice design using heuristics and new strategies

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz S, J. J.; Castillo M, J. A.; Torres V, M.; Perusquia del Cueto, R. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Pelta, D. A. [ETS Ingenieria Informatica y Telecomunicaciones, Universidad de Granada, Daniel Saucedo Aranda s/n, 18071 Granada (Spain); Campos S, Y., E-mail: juanjose.ortiz@inin.gob.m [IPN, Escuela Superior de Fisica y Matematicas, Unidad Profesional Adolfo Lopez Mateos, Edif. 9, 07738 Mexico D. F. (Mexico)

    2010-10-15

    This work show some results of the fuel lattice design in BWRs when some allocation pin rod rules are not taking into account. Heuristics techniques like Path Re linking and Greedy to design fuel lattices were used. The scope of this work is to search about how do classical rules in design fuel lattices affect the heuristics techniques results and the fuel lattice quality. The fuel lattices quality is measured by Power Peaking Factor and Infinite Multiplication Factor at the beginning of the fuel lattice life. CASMO-4 code to calculate these parameters was used. The analyzed rules are the following: pin rods with lowest uranium enrichment are only allocated in the fuel lattice corner, and pin rods with gadolinium cannot allocated in the fuel lattice edge. Fuel lattices with and without gadolinium in the main diagonal were studied. Some fuel lattices were simulated in an equilibrium cycle fuel reload, using Simulate-3 to verify their performance. So, the effective multiplication factor and thermal limits can be verified. The obtained results show a good performance in some fuel lattices designed, even thought, the knowing rules were not implemented. A fuel lattice performance and fuel lattice design characteristics analysis was made. To the realized tests, a dell workstation was used, under Li nux platform. (Author)

  15. In-Flight Evaluation of Noise Levels and Assessment of Active Noise Reduction Systems in the Seahawk S-70B-2 Helicopter

    Science.gov (United States)

    1992-11-01

    Library Qantas Airways Limited Civil Aviation Authority Gas & Fuel Corporation of Vic., Manager Scientific Services Ampol Petroleum (Vic) Pty Ltd...Aircraft 3 2.3 Recording and Measurement System 5 2.4 Analysis Equipment 5 2.5 Test Procedure 5 3. RESULTS 7 3.1 Ambient Noise Levels in the S-70B-2 7...using spectral analysis techniques to determine the acoustic characteristics of this noise, b) measuring at-ear SPLs under the ALPHA helmet and

  16. Fuel processors for fuel cell APU applications

    Science.gov (United States)

    Aicher, T.; Lenz, B.; Gschnell, F.; Groos, U.; Federici, F.; Caprile, L.; Parodi, L.

    The conversion of liquid hydrocarbons to a hydrogen rich product gas is a central process step in fuel processors for auxiliary power units (APUs) for vehicles of all kinds. The selection of the reforming process depends on the fuel and the type of the fuel cell. For vehicle power trains, liquid hydrocarbons like gasoline, kerosene, and diesel are utilized and, therefore, they will also be the fuel for the respective APU systems. The fuel cells commonly envisioned for mobile APU applications are molten carbonate fuel cells (MCFC), solid oxide fuel cells (SOFC), and proton exchange membrane fuel cells (PEMFC). Since high-temperature fuel cells, e.g. MCFCs or SOFCs, can be supplied with a feed gas that contains carbon monoxide (CO) their fuel processor does not require reactors for CO reduction and removal. For PEMFCs on the other hand, CO concentrations in the feed gas must not exceed 50 ppm, better 20 ppm, which requires additional reactors downstream of the reforming reactor. This paper gives an overview of the current state of the fuel processor development for APU applications and APU system developments. Furthermore, it will present the latest developments at Fraunhofer ISE regarding fuel processors for high-temperature fuel cell APU systems on board of ships and aircrafts.

  17. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL)Provides testing for technology readiness of fuel cell systems The FCL investigates, tests and verifies the performance of fuel-cell systems...

  18. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL) Provides testing for technology readiness of fuel cell systems The FCL investigates, tests and verifies the performance of fuel-cell systems...

  19. Fuel cells: A survey

    Science.gov (United States)

    Crowe, B. J.

    1973-01-01

    A survey of fuel cell technology and applications is presented. The operating principles, performance capabilities, and limitations of fuel cells are discussed. Diagrams of fuel cell construction and operating characteristics are provided. Photographs of typical installations are included.

  20. Neuron dynamics in the presence of 1/f noise

    Science.gov (United States)

    Sobie, Cameron; Babul, Arif; de Sousa, Rogério

    2011-05-01

    Interest in understanding the interplay between noise and the response of a nonlinear device cuts across disciplinary boundaries. It is as relevant for unmasking the dynamics of neurons in noisy environments as it is for designing reliable nanoscale logic circuit elements and sensors. Most studies of noise in nonlinear devices are limited to either time-correlated noise with a Lorentzian spectrum (of which the white noise is a limiting case) or just white noise. We use analytical theory and numerical simulations to study the impact of the more ubiquitous “natural” noise with a 1/f frequency spectrum. Specifically, we study the impact of the 1/f noise on a leaky integrate and fire model of a neuron. The impact of noise is considered on two quantities of interest to neuron function: The spike count Fano factor and the speed of neuron response to a small steplike stimulus. For the perfect (nonleaky) integrate and fire model, we show that the Fano factor can be expressed as an integral over noise spectrum weighted by a (low-pass) filter function given by F(t,f)=sinc2(πft). This result elucidates the connection between low-frequency noise and disorder in neuron dynamics. Under 1/f noise, spike dynamics lacks a characteristic correlation time, inducing the leaky and nonleaky models, to exhibit nonergodic behavior and the Fano factor, increasing logarithmically as a function of time. We compare our results to experimental data of single neurons in vivo [Teich, Heneghan, Lowen, Ozaki, and Kaplan, J. Opt. Soc. Am. AJNRSDS1084-752910.1364/JOSAA.14.000529 14, 529 (1997)] and show how the 1/f noise model provides much better agreement than the usual approximations based on Lorentzian noise. The low-frequency noise, however, complicates the case for an information-coding scheme based on interspike intervals by introducing variability in the neuron response time. On a positive note, the neuron response time to a step stimulus is, remarkably, nearly optimal in the presence

  1. Annoyance of low frequency noise and traffic noise

    DEFF Research Database (Denmark)

    Mortensen, F.R.; Poulsen, Torben

    2001-01-01

    The annoyance of different low frequency noise sources was determined and compared to the annoyance from traffic noise. Twenty-two subjects participated in laboratory listening tests. The sounds were presented by loudspeakers in a listening room and the spectra of the low frequency noises were...

  2. Evaluating noise abatement measures using strategic noise maps

    NARCIS (Netherlands)

    Borst, H.C.; Miedema, H.M.E.; Laan, W.P.N. van der; Lohman, W.J.A.

    2006-01-01

    Noise annoyance due to transportation is widespread in industrialized countries and in urban areas in the developing countries. The European Noise Directive (END) requires an assessment of the noise situation as well as the formulation of action plans for the reduction of the number of people

  3. Evaluating noise abatement measures using strategic noise maps

    NARCIS (Netherlands)

    Borst, H.C.; Miedema, H.M.E.; Laan, W.P.N. van der; Lohman, W.J.A.

    2006-01-01

    Noise annoyance due to transportation is widespread in industrialized countries and in urban areas in the developing countries. The European Noise Directive (END) requires an assessment of the noise situation as well as the formulation of action plans for the reduction of the number of people harmfu

  4. Rating environmental noise on the basis of noise maps

    NARCIS (Netherlands)

    Miedema, H.M.E.; Borst, H.C.

    2006-01-01

    A system that rates noise on the basis of noise maps has been developed which is based on empirical exposure-response relationships, so that effects in the community will be lower if the system gives a better rating. It is consistent with noise metrics and effect endpoint chosen in the EU, i.e., it

  5. Noise sensitivity and reactions to noise and other environmental conditions

    NARCIS (Netherlands)

    Miedema, H.M.E.; Vos, H.

    2003-01-01

    This article integrates findings from the literature and new results regarding noise sensitivity. The new results are based on analyses of 28 combined datasets (N=23 038), and separate analyses of a large aircraft noise study (N=10939). Three topics regarding noise sensitivity are discussed, namely,

  6. Guidance Document for Alternative Diesel Fuels Proposed as Drop-In Fuels to Displace Diesel Fuels as Specified By ASTM Specification D975

    Science.gov (United States)

    2014-07-01

    stability is the resistance to change when the fuel is heated. Oxidation stability is the resistance to change when the fuel is in an oxidizing...environment. Storage stability is the resistance to change while the fuel is in storage. Factors that influence storage stability include presence of

  7. Future aviation fuels overview

    Science.gov (United States)

    Reck, G. M.

    1980-01-01

    The outlook for aviation fuels through the turn of the century is briefly discussed and the general objectives of the NASA Lewis Alternative Aviation Fuels Research Project are outlined. The NASA program involves the evaluation of potential characteristics of future jet aircraft fuels, the determination of the effects of those fuels on engine and fuel system components, and the development of a component technology to use those fuels.

  8. Vertical distribution of fuels in Pinus yunnanensis forest and related affecting factors%云南松林可燃物的垂直分布及影响因子

    Institute of Scientific and Technical Information of China (English)

    王叁; 牛树奎; 李德; 王景华; 陈锋; 孙武

    2013-01-01

    In order to understand the effects of fuel loadings spatial distribution on forest fire kinds and behaviors, the canopy fuels and floor fuels of Pinups yunnanensis forests with different canopy density, diameter at breast height ( DBH) , tree height, and stand age and at different altitude, slope grade, position, and aspect in Southwest China were taken as test objects, with the fuel loadings and their spatial distribution characteristics at different vertical layers compared and the fire behaviors in different stands analyzed. The relationships between the fuel loadings and the environmental factors were also analyzed by canonical correspondence analysis ( CCA). In different stands, there existed significant differences in the vertical distribution of fuels. Pinus yunnanensis-oak-Syzy-gium aromaticum, Pinus yunnanensis-oak, and Pinus yunnanensis forests were likely to occur floor fire but not crown fire, while Pinus yunnanensis-Platycladus orientalis, Pinus yunnanensis-Keteleeria fortune, and Keteleeria fortune-Pinus yunnanensis were not only inclined to occur floor fire, but also, the floor fire could be easily transformed into crown fire. The crown fuels were mainly affected by the stand age, altitude, DBH, and tree height, while the floor fuels were mainly by the canopy density, slope grade, altitude, and stand age.%为研究可燃物负荷量空间分布对林火种类和火行为的影响,以川西南地区不同类型云南松林的冠层可燃物和地表可燃物、4个地形因子(海拔、坡度、坡位和坡向)和4个林分因子(郁闭度、胸径、树高和林龄)为对象,比较不同林分相同垂直层面和不同空间层次上的可燃物负荷量及分布特征,分析不同林分的林火行为趋势;并运用典型相关分析(CCA)分析可燃物负荷量与环境因子的关系.结果表明:不同林分组成中,可燃物垂直分布呈显著性差异.云南松-栎类-丁香林、云南松-栎类林和云南松纯林容易发生地表

  9. Noise-Induced Hearing Loss

    Science.gov (United States)

    ... America Information For… Media Policy Makers Noise-Induced Hearing Loss Recommend on Facebook Tweet Share Compartir Hearing plays ... sounds over an extended period. Preventing Noise-Induced Hearing Loss Hearing loss caused by exposure to loud sound ...

  10. Jet pump noise analysis for BWRs

    Energy Technology Data Exchange (ETDEWEB)

    Castillo-Duran, R.; Hernandez-lopez, H.; Ortiz-Villafuerte, J.; Alonso-Vargas, G. [Instituto Nacional de Investigaciones Nucleares, Mexico (Mexico); Calleros-Micheland, G. [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Veracruz (Mexico)

    2004-07-01

    The use of noise analysis for detection of BWR component malfunction is a powerful tool in determining abnormal operation conditions, during the life of a nuclear power plant. Since the eighties, several nuclear reactors have reported problems related with jet pumps and recirculation loops. The NRC (Nuclear Regulatory Commission) recommends performing periodic monitoring to individual pressure drop jet pumps, to prevent structural failure. In this work, noise analysis methods are used for detection of jet pumps abnormal operation conditions in a BWR. Power signals obtained from the backup process computer of a BWR are analyzed with a home-developed software, called NOISE, for noise diagnostic of power signals. The computer program takes individual signals from the tabular report of the process computer. The normalized power spectral density (NPSD) is then obtained, using a Prime Factor Algorithm to calculate the Fast Fourier Transform. The NPSD of the jet pumps pressure drop, of Unit 2 of the Laguna Verde Nuclear Power Plant, showed a noticeable change in jet pump 6 during 2003, considering the period from the startup test to operation during 2003. This abnormal condition was due to that the jet pump throat was partially blocked. The noise analysis methodology is shown to be a useful tool for malfunction detection, and could be applied to create a data bank for monitoring the dynamic behavior of BWR jet pumps. (authors)

  11. Noise minimization in eukaryotic gene expression.

    Directory of Open Access Journals (Sweden)

    Hunter B Fraser

    2004-06-01

    Full Text Available All organisms have elaborate mechanisms to control rates of protein production. However, protein production is also subject to stochastic fluctuations, or "noise." Several recent studies in Saccharomyces cerevisiae and Escherichia coli have investigated the relationship between transcription and translation rates and stochastic fluctuations in protein levels, or more generally, how such randomness is a function of intrinsic and extrinsic factors. However, the fundamental question of whether stochasticity in protein expression is generally biologically relevant has not been addressed, and it remains unknown whether random noise in the protein production rate of most genes significantly affects the fitness of any organism. We propose that organisms should be particularly sensitive to variation in the protein levels of two classes of genes: genes whose deletion is lethal to the organism and genes that encode subunits of multiprotein complexes. Using an experimentally verified model of stochastic gene expression in S. cerevisiae, we estimate the noise in protein production for nearly every yeast gene, and confirm our prediction that the production of essential and complex-forming proteins involves lower levels of noise than does the production of most other genes. Our results support the hypothesis that noise in gene expression is a biologically important variable, is generally detrimental to organismal fitness, and is subject to natural selection.

  12. Noise minimization in eukaryotic gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, Hunter B.; Hirsh, Aaron E.; Giaever, Guri; Kumm, Jochen; Eisen, Michael B.

    2004-01-15

    All organisms have elaborate mechanisms to control rates of protein production. However, protein production is also subject to stochastic fluctuations, or noise. Several recent studies in Saccharomyces cerevisiae and Escherichia coli have investigated the relationship between transcription and translation rates and stochastic fluctuations in protein levels, or more generally, how such randomness is a function of intrinsic and extrinsic factors. However, the fundamental question of whether stochasticity in protein expression is generally biologically relevant has not been addressed, and it remains unknown whether random noise in the protein production rate of most genes significantly affects the fitness of any organism. We propose that organisms should be particularly sensitive to variation in the protein levels of two classes of genes: genes whose deletion is lethal to the organism and genes that encode subunits of multiprotein complexes. Using an experimentally verified model of stochastic gene expression in S. cerevisiae, we estimate the noise in protein production for nearly every yeast gene, and confirm our prediction that the production of essential and complex-forming proteins involves lower levels of noise than does the production of most other genes. Our results support the hypothesis that noise in gene expression is a biologically important variable, is generally detrimental to organismal fitness, and is subject to natural selection.

  13. Fuel composition and secondary organic aerosol formation: gas-turbine exhaust and alternative aviation fuels.

    Science.gov (United States)

    Miracolo, Marissa A; Drozd, Greg T; Jathar, Shantanu H; Presto, Albert A; Lipsky, Eric M; Corporan, Edwin; Robinson, Allen L

    2012-08-07

    A series of smog chamber experiments were performed to investigate the effects of fuel composition on secondary particulate matter (PM) formation from dilute exhaust from a T63 gas-turbine engine. Tests were performed at idle and cruise loads with the engine fueled on conventional military jet fuel (JP-8), Fischer-Tropsch synthetic jet fuel (FT), and a 50/50 blend of the two fuels. Emissions were sampled into a portable smog chamber and exposed to sunlight or artificial UV light to initiate photo-oxidation. Similar to previous studies, neat FT fuel and a 50/50 FT/JP-8 blend reduced the primary particulate matter emissions compared to neat JP-8. After only one hour of photo-oxidation at typical atmospheric OH levels, the secondary PM production in dilute exhaust exceeded primary PM emissions, except when operating the engine at high load on FT fuel. Therefore, accounting for secondary PM production should be considered when assessing the contribution of gas-turbine engine emissions to ambient PM levels. FT fuel substantially reduced secondary PM formation in dilute exhaust compared to neat JP-8 at both idle and cruise loads. At idle load, the secondary PM formation was reduced by a factor of 20 with the use of neat FT fuel, and a factor of 2 with the use of the blend fuel. At cruise load, the use of FT fuel resulted in no measured formation of secondary PM. In every experiment, the secondary PM was dominated by organics with minor contributions from sulfate when the engine was operated on JP-8 fuel. At both loads, FT fuel produces less secondary organic aerosol than JP-8 because of differences in the composition of the fuels and the resultant emissions. This work indicates that fuel reformulation may be a viable strategy to reduce the contribution of emissions from combustion systems to secondary organic aerosol production and ultimately ambient PM levels.

  14. Catalytic Fuel Conversion Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This facility enables unique catalysis research related to power and energy applications using military jet fuels and alternative fuels. It is equipped with research...

  15. Fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, Hirofumi.

    1989-05-22

    This invention aims to maintain a long-term operation with stable cell output characteristics by uniformly supplying an electrolyte from the reserver to the matrix layer over the entire matrix layer, and further to prevent the excessive wetting of the catalyst layer by smoothly absorbing the volume change of the electrolyte, caused by the repeated stop/start-up of the fuel cell, within the reserver system. For this purpose, in this invention, an electrolyte transport layer, which connects with an electrolyte reservor formed at the electrode end, is partly formed between the electrode material and the catalyst layer; a catalyst layer, which faces the electrolyte transport layer, has through-holes, which connect to the matrix, dispersely distributed. The electrolyte-transport layer is a thin sheet of a hydrophilic fibers which are non-wovens of such fibers as carbon, silicon carbide, silicon nitride or inorganic oxides. 11 figs.

  16. Intercode Advanced Fuels and Cladding Comparison Using BISON, FRAPCON, and FEMAXI Fuel Performance Codes

    Science.gov (United States)

    Rice, Aaren

    As part of the Department of Energy's Accident Tolerant Fuels (ATF) campaign, new cladding designs and fuel types are being studied in order to help make nuclear energy a safer and more affordable source for power. This study focuses on the implementation and analysis of the SiC cladding and UN, UC, and U3Si2 fuels into three specific nuclear fuel performance codes: BISON, FRAPCON, and FEMAXI. These fuels boast a higher thermal conductivity and uranium density than traditional UO2 fuel which could help lead to longer times in a reactor environment. The SiC cladding has been studied for its reduced production of hydrogen gas during an accident scenario, however the SiC cladding is a known brittle and unyielding material that may fracture during PCMI (Pellet Cladding Mechanical Interaction). This work focuses on steady-state operation with advanced fuel and cladding combinations. By implementing and performing analysis work with these materials, it is possible to better understand some of the mechanical interactions that could be seen as limiting factors. In addition to the analysis of the materials themselves, a further analysis is done on the effects of using a fuel creep model in combination with the SiC cladding. While fuel creep is commonly ignored in the traditional UO2 fuel and Zircaloy cladding systems, fuel creep can be a significant factor in PCMI with SiC.

  17. Reactivity and burnout of wood fuels

    DEFF Research Database (Denmark)

    Dall'Ora, Michelangelo

    This thesis deals with the combustion of wood in pulverised fuel power plants. In this type of boiler, the slowest step in the wood conversion process is char combustion, which is one of the factors that not only determine the degree of fuel burnout, but also affect the heat release profile...

  18. Noise Measurement in Microsensor Applications

    OpenAIRE

    Moghaddam, Saeed

    2016-01-01

    In this research, spectral coherence noise measurement technique is used to measure noise of capacitive accelerometers, based on measuring the spectral coherence and outputs of two identical sensors exposed to the same input stimulus. This effective technique can be applied to any sensor characterization problem where there is interest in distinguishing instrumental noise from background noise. The simulation study has been done in MATLAB to verify the proposed method reliability to calculate...

  19. Cost reductions of fuel cells for transport applications: fuel processing options

    Science.gov (United States)

    Teagan, W. P.; Bentley, J.; Barnett, B.

    The highly favorable efficiency/environmental characteristics of fuel cell technologies have now been verified by virtue of recent and ongoing field experience. The key issue regarding the timing and extent of fuel cell commercialization is the ability to reduce costs to acceptable levels in both stationary and transport applications. It is increasingly recognized that the fuel processing subsystem can have a major impact on overall system costs, particularly as ongoing R&D efforts result in reduction of the basic cost structure of stacks which currently dominate system costs. The fuel processing subsystem for polymer electrolyte membrane fuel cell (PEMFC) technology, which is the focus of transport applications, includes the reformer, shift reactors, and means for CO reduction. In addition to low cost, transport applications require a fuel processor that is compact and can start rapidly. This paper describes the impact of factors such as fuel choice, operating temperature, material selection, catalyst requirements, and controls on the cost of fuel processing systems. There are fuel processor technology paths which manufacturing cost analyses indicate are consistent with fuel processor subsystem costs of under 150/kW in stationary applications and 30/kW in transport applications. As such, the costs of mature fuel processing subsystem technologies should be consistent with their use in commercially viable fuel cell systems in both application categories.

  20. ASSESSMENT OF WORK ZONE NOISE LEVELS AT A CEMENT ...

    African Journals Online (AJOL)

    Osondu

    2012-03-24

    Mar 24, 2012 ... factors affecting human health in today's ... Cement production is one of the major ... The offices and restaurant were considered as .... Figure 1 Classification of noise levels in different production sections during operation ...

  1. Hydraulic characteristics of HANARO fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S.; Chung, H. J.; Chun, S. Y.; Yang, S. K.; Chung, M. K. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    This paper presents the hydraulic characteristics measured by using LDV (Laser Doppler Velocimetry) in subchannels of HANARO, KAERI research reactor, fuel bundle. The fuel bundle consists of 18 axially finned rods with 3 spacer grids, which are arranged in cylindrical configuration. The effects of the spacer grids on the turbulent flow were investigated by the experimental results. Pressure drops for each component of the fuel bundle were measured, and the friction factors of fuel bundle and loss coefficients for the spacer grids were estimated from the measured pressure drops. Implications regarding the turbulent thermal mixing were discussed. Vibration test results measured by using laser vibrometer were presented. 9 refs., 12 figs. (Author)

  2. Practical ranges of loudness levels of various types of environmental noise, including traffic noise, aircraft noise, and industrial noise

    NARCIS (Netherlands)

    Salomons, E.M.; Janssen, S.A.

    2011-01-01

    In environmental noise control one commonly employs the A-weighted sound level as an approximate measure of the effect of noise on people. A measure that is more closely related to direct human perception of noise is the loudness level. At constant A-weighted sound level, the loudness level of a noi

  3. Low-frequency noise complaints

    DEFF Research Database (Denmark)

    Pedersen, Christian Sejer; Møller, Henrik; Persson-Waye, Kerstin

    2006-01-01

    In Denmark and in other industrialized countries there are cases where people complain about annoying low-frequency or infrasonic noise in their homes. Besides noise annoyance people often report other adverse effects such as insomnia, headache, lack of concentration etc. In many cases the noise...

  4. NOISE IN TEXTILE MILLS

    Directory of Open Access Journals (Sweden)

    P. Meshgi

    1977-06-01

    Full Text Available The mean noise levels were measured in the different sections of six representative mills in the Isfahan area, and audiometric measurements were made in 282 male workers employed in these mills. The mean noise levels were on average 95 dBA in the weaving sections and 88 d BA in the spinning sections. The audiometric findings showed a significant loss of gearing in the textile workers as compared to controls who were employed in a quiet environment. The study indicated that noisiness depended; on the whole, on the age and number of machines deployed per unit area of shop-floor. On the basis of this study certain recommendations were made to improve the working conditions.

  5. Ex / Noise / CERN / Deerhoof

    CERN Multimedia

    CERN, SM18,

    2015-01-01

    Indie rockers Deerhoof battled with the noise of CERN’s magnet test facilities on 30 August 2015. The band visited CERN at the invitation of ATLAS physicist James Beacham, whose pilot project Ex/Noise/CERN collides experimental music artists with experimental particle physics. Credits: -Producer- CERN Video Productions James Beacham François Briard -Director- Noemi Caraban -Camera- Yann Krajewski Piotr Traczyk Noemi Caraban -Crane operator- Antonio Henrique Jorge-Costa -Live recording at CERN- Mixing at Rec studio/Geneva By Serge Morattel -Infography- Daniel Dominguez Noemi Caraban -Deerhoof- John Dieterich Satomi Matsuzaki Ed Rodriguez Greg Saunier w/Deron Pulley SPECIAL THANKS TO: Michal Strychalski Marta Bajko Maryline Charrondiere Luca Bottura Christian Giloux Rodrigue Faes Mariane Catallon Georgina Hobgen Hailey Reissman Marine Bass

  6. Development and application of reactor noise diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Joakim K.H

    1999-04-01

    the paper presented here, we elaborate a modified and successful factorisation technique that takes the noise structure and the approximations performed into account. Due to an unseated fuel element, a local density wave oscillation appeared in the Swedish BWR Forsmark-1 in 1996. It is of great practical importance to locate the responsible element as soon as possible. We have developed a method for the localisation of such a thermohydraulic channel instability. The localisation method was tested on simulated data and then applied to a measurement taken in Forsmark-1 in early 1997. The results demonstrate the applicability and accuracy of the method. The noise present in the Ringhals PWRs has been investigated and in the course of this work, we have developed a new strategy towards the analysis of core barrel vibrations (CBM). This new approach unites the CBM analysis in the time and frequency domains. We have also developed and applied a new model for the determination of vibration properties such as the amplitude, amount of anisotropy and the preferred direction of the vibrations. This method is quantitative and suitable for long-term trend analysis of CBM vibrations 69 refs, 19 figs

  7. Development and application of reactor noise diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Joakim K.H

    1999-04-01

    the paper presented here, we elaborate a modified and successful factorisation technique that takes the noise structure and the approximations performed into account. Due to an unseated fuel element, a local density wave oscillation appeared in the Swedish BWR Forsmark-1 in 1996. It is of great practical importance to locate the responsible element as soon as possible. We have developed a method for the localisation of such a thermohydraulic channel instability. The localisation method was tested on simulated data and then applied to a measurement taken in Forsmark-1 in early 1997. The results demonstrate the applicability and accuracy of the method. The noise present in the Ringhals PWRs has been investigated and in the course of this work, we have developed a new strategy towards the analysis of core barrel vibrations (CBM). This new approach unites the CBM analysis in the time and frequency domains. We have also developed and applied a new model for the determination of vibration properties such as the amplitude, amount of anisotropy and the preferred direction of the vibrations. This method is quantitative and suitable for long-term trend analysis of CBM vibrations 69 refs, 19 figs

  8. Noise Phobia in Dog

    Directory of Open Access Journals (Sweden)

    Mangle

    Full Text Available Fear of thunderstorms and other forms of noise phobia are common problems in dogs. Administering medications along with changing the pet’s environment, and using behavior modification techniques can help ease the fear. Above all, do not give your pet any attention or reward when he is showing signs of fear; this will only reinforce the fearful behavior. [Veterinary World 2008; 1(11.000: 351-352

  9. Aircraft Noise Prediction

    OpenAIRE

    2014-01-01

    This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper add...

  10. Model of flicker noise effects on phase noise in oscillators

    Science.gov (United States)

    Centurelli, Francesco; Ercolani, Alessandro; Tommasino, Pasquale; Trifiletti, Alessandro

    2003-05-01

    Phase noise models that describe the near-carrier spectrum in an accurate but insightful way are needed, to better optimize the oscillator design. In this paper we present a model to describe the effect of flicker noise sources on the phase noise of an oscillator, that can be applied both to linear oscillators and to nonlinear structures like relaxation and ring oscillators, so extending previous works that considered only the effect of the flicker noise superimposed to the control voltage of a VCO. In the phase noise of an oscillator we can separate the effect of high frequency noise sources, that can be described by a short-time-constant system, and the effect of low frequency noises (mostly flicker sources), described by a system with time constants much slower than the oscillation period. Flicker noise has been considered to cause a change in the circuit bias point; this bias point change can be mapped in a shift of the oscillation frequency by exploiting Barkhausen conditions (for linear oscillators) or obtaining this link by simulations. The power spectral density of the oscillator can then be obtained as the probability distribution of the oscillation frequency, starting from the flicker noise probability distribution. If the effect of high frequency noise sources is also taken into account, the overall oscillator spectrum can be obtained as a convolution of the spectrum due to flicker sources with the Lorentzian-shaped spectrum due to white noise sources, in analogy with the description of inhomogeneous broadening of laser linewidth.

  11. Noise Analysis of MAIA System and Possible Noise Suppression

    Directory of Open Access Journals (Sweden)

    J. Svihlik

    2011-04-01

    Full Text Available This paper is devoted to the noise analysis and noise suppression in a system for double station observation of the meteors now known as MAIA (Meteor Automatic Imager and Analyzer. The noise analysis is based on acquisition of testing video sequences in different light conditions and their further statistical evaluation. The main goal is to find a suitable noise model and subsequently determine if the noise is signal dependent or not. Noise and image model in the wavelet domain should be based on Gaussian mixture model (GMM or Generalized Laplacian Model (GLM and the model parameters should be estimated by moment method. Furthermore, noise should be modeled by GMM or GLM also in the space domain. GMM and GLM allow to model various types of probability density functions. Finally the advanced denoising algorithm using Bayesian estimator is applied and its performance is verified.

  12. Physical Mechanisms of Seismometer Site Noise and Self-Noise

    Science.gov (United States)

    Bainbridge, G. S.; Parker, T.; Townsend, B.; Upadhyaya, S.

    2016-12-01

    Ideally any seismometer installation should have a noise level corresponding to a predefined specification, to ensure the noise level is below the signals of interest. In practice seismic data may contain unforeseen noise artifacts and may vary widely in quality from one station to another due to particular site conditions, problematic installation methods, or a defective or unsuitable instrument. Also some modes of ground motion can be considered as noise, for example local vibration or tilt motion obscuring teleseismic signals. In this study we present an analysis of the physical phenomena which most commonly cause noise artifacts in broadband seismic data, based on data from controlled laboratory experiments as well as field installations. Each different physical mechanism gives rise to noise with particular distinguishing characteristics which can enable the user to diagnose noise symptoms, trace them to a root cause, take corrective action, and evolve towards best practices for particular environments and use cases.

  13. Ambiguity functions and noise floor suppression in random noise radar

    Science.gov (United States)

    Axelsson, Sune R. J.

    2006-09-01

    Noise radar can be used in a great number of applications including SAR. The non-periodic waveform suppresses the range ambiguity and reduces the probability of intercept and interference. Due to the randomness of the waveform, a noise floor limiting the possible side lobe suppression accompanies the correlation integral involved. In strong clutter scenes with dominant reflectors, the induced noise floor can be too high and further suppression is needed. In this paper, the ambiguity function of random noise waveforms is first analyzed, and an improved formulation is introduced to include the noise floor effect. The use of mismatched filtering for improved sidelobe suppression is then discussed. Finally, an iterative subtraction algorithm is analyzed for noise floor cancellation in the presence of dominating reflectors. This method is successfully tested on random step frequency radar data and noise sodar data.

  14. A GUIDE TO FUEL PERFORMANCE

    Energy Technology Data Exchange (ETDEWEB)

    LITZKE,W.

    2004-08-01

    Heating oil, as its name implies, is intended for end use heating consumption as its primary application. But its identity in reference name and actual chemical properties may vary based on a number of factors. By name, heating oil is sometimes referred to as gas oil, diesel, No. 2 distillate (middle distillate), or light heating oil. Kerosene, also used as a burner fuel, is a No. 1 distillate. Due to the higher heat content and competitive price in most markets, No. 2 heating oil is primarily used in modern, pressure-atomized burners. Using No. 1 oil for heating has the advantages of better cold-flow properties, lower emissions, and better storage properties. Because it is not nearly as abundant in supply, it is often markedly more expensive than No. 2 heating oil. Given the advanced, low-firing rate burners in use today, the objective is for the fuel to be compatible and achieve combustion performance at the highest achievable efficiency of the heating systems--with minimal service requirements. Among the Oil heat industry's top priorities are improving reliability and reducing service costs associated with fuel performance. Poor fuel quality, fuel degradation, and contamination can cause burner shut-downs resulting in ''no-heat'' calls. Many of these unscheduled service calls are preventable with routine inspection of the fuel and the tank. This manual focuses on No. 2 heating oil--its performance, properties, sampling and testing. Its purpose is to provide the marketer, service manager and technician with the proper guidelines for inspecting the product, maintaining good fuel quality, and the best practices for proper storage. Up-to-date information is also provided on commercially available fuel additives, their appropriate use and limitations.

  15. Aircraft noise prediction

    Science.gov (United States)

    Filippone, Antonio

    2014-07-01

    This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper addresses items for further research and development. Examples are shown for several airplanes, including the Airbus A319-100 (CFM engines), the Bombardier Dash8-Q400 (PW150 engines, Dowty R408 propellers) and the Boeing B737-800 (CFM engines). Predictions are done with the flight mechanics code FLIGHT. The transfer function between flight mechanics and the noise prediction is discussed in some details, along with the numerical procedures for validation and verification. Some code-to-code comparisons are shown. It is contended that the field of aircraft noise prediction has not yet reached a sufficient level of maturity. In particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.

  16. Scaling model for a speed-dependent vehicle noise spectrum

    Directory of Open Access Journals (Sweden)

    Giovanni Zambon

    2017-06-01

    Full Text Available Considering the well-known features of the noise emitted by moving sources, a number of vehicle characteristics such as speed, unladen mass, engine size, year of registration, power and fuel were recorded in a dedicated monitoring campaign performed in three different places, each characterized by different number of lanes and the presence of nearby reflective surfaces. A full database of 144 vehicles (cars was used to identify statistically relevant features. In order to compare the vehicle transit noise in different environmental condition, all 1/3-octave band spectra were normalized and analysed. Unsupervised clustering algorithms were employed to group together spectrum levels with similar profiles. Our results corroborate the well-known fact that speed is the most relevant characteristic to discriminate between different vehicle noise spectrum. In keeping with this fact, we present a new approach to predict analytically noise spectra for a given vehicle speed. A set of speed-dependent analytical functions are suggested in order to fit the normalized average spectrum profile at different speeds. This approach can be useful for predicting vehicle speed based purely on its noise spectrum pattern. The present work is complementary to the accurate analysis of noise sources based on the beamforming technique.

  17. An assessment of psychological noise reduction by landscape plants.

    Science.gov (United States)

    Yang, Fan; Bao, Zhi Yi; Zhu, Zhu Jun

    2011-04-01

    The emphasis in the term 'Green Transportation' is on the word 'green'. Green transportation focuses on the construction of a slow transport system with a visually pleasing, easy and secure trip environment composed of urban parks, green roadside spaces and some other space that is full of landscape plants. This trip environment encourages residents to make trip choices that reduce fuel consumption and pollution and is one of the most important ways of popularizing green transportation. To study the psychological benefits provided by urban parks and other landscape environments, we combined a subjective approach (a questionnaire) with an objective quantitative approach (emotional tests using an electroencephalogram; EEG). Using a questionnaire survey, we found that 90% of the subjects believed that landscape plants contribute to noise reduction and that 55% overrated the plants' actual ability to attenuate noise. Two videos (showing a traffic scene and a plant scene) were shown to 40 participants on video glasses. We detected and recorded EEG values with a portable electroencephalograph, and a comparison between the results of the two groups revealed that there was a highly significant asymmetry between the EEG activity of the vegetation scene and traffic scene groups. The results suggest that the emotions aroused by noise and visual stimuli are manifested in the synchronization of beta frequency band and the desynchronization of alpha frequency band, indicating that landscape plants can moderate or buffer the effects of noise. These findings indicate that landscape plants provide excess noise attenuating effects through subjects' emotional processing, which we term 'psychological noise reduction'.

  18. Air-borne noise of thermal module and system for notebook personal computers:experimental study

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Thermal performance is the most important issue to be considered when a thermal module is designed for a notebook personal computer (PC).Because the fan causes air-borne noise and affects the user's comfort,the acoustic characteristics of the module attract more attention.Experiments were conducted to study the noise sources,the noise characteristic and the main factors influencing the noise level.The difference between the air-borne noise of the thermal module and the whole computer system was analyzed and its propagating characteristics were derived.The influence of I/O ports on the air-borne noise was also studied experimentally.

  19. Acoustic Prediction Methodology and Test Validation for an Efficient Low-Noise Hybrid Wing Body Subsonic Transport

    Science.gov (United States)

    Kawai, Ronald T. (Compiler)

    2011-01-01

    This investigation was conducted to: (1) Develop a hybrid wing body subsonic transport configuration with noise prediction methods to meet the circa 2007 NASA Subsonic Fixed Wing (SFW) N+2 noise goal of -52 dB cum relative to FAR 36 Stage 3 (-42 dB cum re: Stage 4) while achieving a -25% fuel burned compared to current transports (re :B737/B767); (2) Develop improved noise prediction methods for ANOPP2 for use in predicting FAR 36 noise; (3) Design and fabricate a wind tunnel model for testing in the LaRC 14 x 22 ft low speed wind tunnel to validate noise predictions and determine low speed aero characteristics for an efficient low noise Hybrid Wing Body configuration. A medium wide body cargo freighter was selected to represent a logical need for an initial operational capability in the 2020 time frame. The Efficient Low Noise Hybrid Wing Body (ELNHWB) configuration N2A-EXTE was evolved meeting the circa 2007 NRA N+2 fuel burn and noise goals. The noise estimates were made using improvements in jet noise shielding and noise shielding prediction methods developed by UC Irvine and MIT. From this the Quiet Ultra Integrated Efficient Test Research Aircraft #1 (QUIET-R1) 5.8% wind tunnel model was designed and fabricated.

  20. Fuel corrosion processes under waste disposal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Shoesmith, D.W. [Univ. of Western Ontario, Dept. of Chemistry, London, Ontario (Canada)

    1999-09-01

    Under the oxidizing conditions likely to be encountered in the Yucca Mountain Repository, fuel dissolution is a corrosion process involving the coupling of the anodic dissolution of the fuel with the cathodic reduction of oxidants available within the repository. The oxidants potentially available to drive fuel corrosion are environmental oxygen, supplied by the transport through the permeable rock of the mountain and molecular and radical species produced by the radiolysis of available aerated water. The mechanism of these coupled anodic and cathodic reactions is reviewed in detail. While gaps in understanding remain, many kinetic features of these reactions have been studied in considerable detail, and a reasonably justified mechanism for fuel corrosion is available. The corrosion rate is determined primarily by environmental factors rather than the properties of the fuel. Thus, with the exception of increase in rate due to an increase in surface area, pre-oxidation of the fuel has little effect on the corrosion rate.

  1. Local Fuel Rod Crud Prediction Tool Applications

    Energy Technology Data Exchange (ETDEWEB)

    Krammen, Michael A.; Karoutas, Zeses E.; Wang, Guoqiang; Young, Michael Y

    2009-06-15

    A code system with attendant methods has been developed for modeling local fuel rod crud. This tool is used to perform the Crud Induced Localized Corrosion (CILC) risk assessment recommended by the EPRI crud and corrosion guidelines, which were developed in response to the INPO zero fuel failures by 2010 initiatives. The methodology is in production use. This paper will describe the range of problems the methodology has already been applied to and the especial pertinence to low duty fuel applications. The methodology begins with Computational Fluid Dynamics (CFD) computations over a fuel assembly grid span. The CFD results provide detailed relative variations in local heat transfer coefficient over the grid span. These very local relative variations are used to determine very local thermal hydraulic conditions over the entire axial length of every fuel rod in a reactor core over the life of the rod in reactor. The expansion using the local relative variations is currently accomplished with the HIDUTYDRV code. The very local thermal hydraulic conditions are combined with reactor coolant crud concentrations derived from EPRI BOA analysis as input to models for predicting very local fuel rod crud deposition. The reactor coolant crud concentrations are determined over each reactor cycle by reactor system wide crud mass balance calculations. The reactor coolant crud concentrations are used to calculate local crud thickness using mass transfer models which are a function of the local thermal conditions. The advanced crud deposition models also include models for calculating local crud dryout. Local crud deposition and crud dryout are strongly dependent on very local boiling or steaming, which are predicted through the translation of the CFD results. The local crud thickness and degree of local crud dryout are key factors in determining the margin or risk for local fuel rod cladding crud induced fuel failure. The development and first application of these methods was in

  2. Effects of uncertainty in SAPRC90 rate constants and selected product yields on reactivity adjustment factors for alternative fuel vehicle emissions. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bergin, M.S.; Russell, A.G.; Yang, Y.J.; Milford, J.B.; Kirchner, F.; Stockwell, W.R.

    1996-07-01

    Tropospheric ozone is formed in the atmosphere by a series of reactions involving volatile organic compounds (VOCs) and nitrogen oxides (NO{sub x}). While NOx emissions are primarily composed of only two compounds, nitrogen oxide (NO) and nitrogen dioxide (NO{sub 2}), there are hundreds of different VOCs being emitted. In general, VOCs promote ozone formation, however, the rate and extent of ozone produced by the individual VOCs varies considerably. For example, it is widely acknowledged that formaldehyde (HCHO) is a very reactive VOC, and produces ozone rapidly and efficiently under most conditions. On the other hand, VOCs such as methane, ethane, propane, and methanol do not react as quickly, and are likely to form less urban ozone than a comparable mass of HCHO. The difference in ozone forming potential is one of the bases for the use of alternative fuels. The fuels considered in this study included compressed natural gas, LPG, mixtures of methanol and gasoline, ethanol and gasoline, and a reformulated gasoline.

  3. Plant Performance of Solid Oxide Fuel Cell Systems Fed by Alternative Fuels

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2016-01-01

    Different plant design for several fuel types such as natural gas, methanol, ethanol, DME, ammonia and pure hydrogen are presented and analysed. Anode recirculation which is an important issue in SOFC plants are also explored and studied. It is shown that depending on type of the fuel whether fuel...... recirculation is needed or not and if so then what would be the effect of anode recycling on plant efficiency. A single study with similar conditions and prerequisites will thus reveal the importance of fuel recirculation on plant performance with alternative fuels. It is also shown that increasing anode...... recycle increases plant efficiency only if fuel utilization factor is low. Other important issues such as why plant efficiency is lower when it is fed with hydrogen or biogas compared to when it is fed by other fuels such as methanol, ethanol, DME and ammonia will also be discussed and explained...

  4. 营运货车道路运行油耗及碳排放因子研究%Research on Fuel Consumption & Carbon Emission Factor of Road Freight Trucks

    Institute of Scientific and Technical Information of China (English)

    彭美春; 李嘉如; 胡红斐

    2015-01-01

    针对营运货车实际道路运行油耗及碳排放因子进行了测算,以不同载质量的125辆营运货车为试验车辆,采用车载测试方法采集了连续6个月车辆运行油耗、里程等数据,运用数据甄别筛选、正态分布检验、均值求解、误差分析、质量控制分析等方法进行数据处理统计分析,测算出各类营运货车百公里油耗均值与偏差,并基于碳平衡方法计算出各类货车的碳排放因子均值。测算结果可用于对营运货车道路运行油耗和碳排放水平进行评价,及对碳排放总量进行估算。%Fuel consumption and carbon emission factor of road freight trucks are measured. A total of 125 road freight trucks of different payload mass are chosen for test. The study collects the vehicle operating data including fuel consumption, driving mileage and so on for 6 months continuously by test device on vehicle, and test data are processed for statistic analysis with the methods of data screening, normal distribution test, solution of mean value, error analysis, quality control methods, etc, through which the mean value and deviation of fuel consumption of different freight trucks and average carbon emission factor based on carbon neutral principle for 5 kinds of freight vehicle. The measurement results can be used in evaluation of the fuel consumption and carbon emission of freight trucks as well as estimation of total carbon emission.

  5. Optimization of Resilient Wheels for Rolling Noise Control

    Science.gov (United States)

    BOUVET, PASCAL; VINCENT, NICOLAS; COBLENTZ, ARNAUD; DEMILLY, FRANÇOIS

    2000-03-01

    Resilient wheels are currently used on light rail systems such as tramways to prevent squealing noise and to reduce impact noise. On the other hand, they are rarely found on main lines (passenger rolling stock and freight rolling stock). Although manufacturers often claim that resilient wheels are favourable for rolling noise control, no extensive theoretical investigation confirming this statement has been published to date. In this paper, it is shown how resilient wheels can be effectively optimised in order to reduce rolling noise emission, compared to a conventional monobloc wheel. A preliminary analysis of the physical phenomena accounting for rolling noise generation emphasizes the key design parameters affecting both wheel and radiation. These parameters are the radial dynamic stiffness and damping loss factor of the rubber layer. The tread mass is also relevant. The influence of these design parameters is then qualified by a parametric study performed with the TWINS software. An optimum radial dynamic stiffness of the resilient layer is found which depends on operating conditions. Reductions in overall rolling noise up to 3 dB(A) are calculated for the configurations investigated. However, poor selection of the design parameters can lead to a noise increase compared to a standard monobloc wheel. It is also shown that a proper design for rolling noise control will not affect wheel efficiency with regard to squeal noise.

  6. Assessment of honking impact on traffic noise in urban traffic environment of Nagpur, India.

    Science.gov (United States)

    Vijay, Ritesh; Sharma, Asheesh; Chakrabarti, Tapan; Gupta, Rajesh

    2015-01-01

    In context of increasing traffic noise in urban India, the objective of the research study is to assess noise due to heterogeneous traffic conditions and the impact of honking on it. Traffic volume, noise levels, honking, road geometry and vehicular speed were measured on national highway, major and minor roads in Nagpur, India. Initial study showed lack of correlation between traffic volume and equivalent noise due to some factors, later identified as honking, road geometry and vehicular speed. Further, frequency analysis of traffic noise showed that honking contributed an additional 2 to 5 dB (A) noise, which is quite significant. Vehicular speed was also found to increase traffic noise. Statistical method of analysis of variance (ANOVA) confirms that frequent honking (p impact on traffic noise apart from traffic volume and type of road. The study suggests that honking must also be a component in traffic noise assessment and to identify and monitor "No Honking" zones in urban agglomerations.

  7. Underwater vehicle sonar self-noise prediction based on genetic algorithms and neural network

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-guang; SHI Zhong-kun

    2006-01-01

    The factors that influence underwater vehicle sonar self-noise are analyzed, and genetic algorithms and a back propagation (BP) neural network are combined to predict underwater vehicle sonar self-noise. The experimental results demonstrate that underwater vehicle sonar self-noise can be predicted accurately by a GA-BP neural network that is based on actual underwater vehicle sonar data.

  8. Assessment of ambient noise levels in the intensive care unit of a university hospital

    Directory of Open Access Journals (Sweden)

    Hatem O Qutub

    2009-01-01

    Conclusion : Some sources of environmental noise, such as the use of oxygen, suction equipment or respirators are unavoidable. Nevertheless, hospital ICUs should have measures to minimize the level of exposure to noise in the ICU. Further research in this area might focus on the noise level and other modifiable environmental stress factors in the ICU that affect patients as well as the staff.

  9. Noise tolerant spatiotemporal chaos computing

    Energy Technology Data Exchange (ETDEWEB)

    Kia, Behnam; Kia, Sarvenaz; Ditto, William L. [Department of Physics and Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822 (United States); Lindner, John F. [Physics Department, The College of Wooster, Wooster, Ohio 44691 (United States); Sinha, Sudeshna [Indian Institute of Science Education and Research (IISER), Mohali, Punjab 140306 (India)

    2014-12-01

    We introduce and design a noise tolerant chaos computing system based on a coupled map lattice (CML) and the noise reduction capabilities inherent in coupled dynamical systems. The resulting spatiotemporal chaos computing system is more robust to noise than a single map chaos computing system. In this CML based approach to computing, under the coupled dynamics, the local noise from different nodes of the lattice diffuses across the lattice, and it attenuates each other's effects, resulting in a system with less noise content and a more robust chaos computing architecture.

  10. Noise tolerant spatiotemporal chaos computing.

    Science.gov (United States)

    Kia, Behnam; Kia, Sarvenaz; Lindner, John F; Sinha, Sudeshna; Ditto, William L

    2014-12-01

    We introduce and design a noise tolerant chaos computing system based on a coupled map lattice (CML) and the noise reduction capabilities inherent in coupled dynamical systems. The resulting spatiotemporal chaos computing system is more robust to noise than a single map chaos computing system. In this CML based approach to computing, under the coupled dynamics, the local noise from different nodes of the lattice diffuses across the lattice, and it attenuates each other's effects, resulting in a system with less noise content and a more robust chaos computing architecture.

  11. Noise-induced coherent switch

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Taking the famous genetic toggle switch as an example,we numerically investigated the effect of noise on bistability.We found that extrinsic noise resulting from stochastic fluctuations in synthesis and degradation rates and from the environmental fluctuation in gene regulatory processes can induce coherent switch,and that there is an optimal noise intensity such that the noise not only can induce this switch,but also can amplify a weak input signal.In addition,we found that the intrinsic noise introduced through the Poisson τ-leap algorithm cannot induce such a switch.

  12. Noise-Mediated Generalized Synchronization

    Institute of Scientific and Technical Information of China (English)

    CHEN Yue-Hua; WU Zhi-Yuan; YANG Jun-Zhong

    2007-01-01

    @@ We investigate a drive-response system by considering the impacts of noise on generalized synchronization (GS).It is found that a small amount of noise can turn the system from desynchronization to the GS state in the resonant case no matter how noise is injected into the system. In the non-resonant case, noise with intensity in a certain range is helpful in building GS only when the noise is injected to the driving system. The mechanism behind the observed phenomena is discussed.

  13. Instrument Variables for Reducing Noise in Parallel MRI Reconstruction

    Directory of Open Access Journals (Sweden)

    Yuchou Chang

    2017-01-01

    Full Text Available Generalized autocalibrating partially parallel acquisition (GRAPPA has been a widely used parallel MRI technique. However, noise deteriorates the reconstructed image when reduction factor increases or even at low reduction factor for some noisy datasets. Noise, initially generated from scanner, propagates noise-related errors during fitting and interpolation procedures of GRAPPA to distort the final reconstructed image quality. The basic idea we proposed to improve GRAPPA is to remove noise from a system identification perspective. In this paper, we first analyze the GRAPPA noise problem from a noisy input-output system perspective; then, a new framework based on errors-in-variables (EIV model is developed for analyzing noise generation mechanism in GRAPPA and designing a concrete method—instrument variables (IV GRAPPA to remove noise. The proposed EIV framework provides possibilities that noiseless GRAPPA reconstruction could be achieved by existing methods that solve EIV problem other than IV method. Experimental results show that the proposed reconstruction algorithm can better remove the noise compared to the conventional GRAPPA, as validated with both of phantom and in vivo brain data.

  14. Instrument Variables for Reducing Noise in Parallel MRI Reconstruction

    Science.gov (United States)

    Lin, Hong

    2017-01-01

    Generalized autocalibrating partially parallel acquisition (GRAPPA) has been a widely used parallel MRI technique. However, noise deteriorates the reconstructed image when reduction factor increases or even at low reduction factor for some noisy datasets. Noise, initially generated from scanner, propagates noise-related errors during fitting and interpolation procedures of GRAPPA to distort the final reconstructed image quality. The basic idea we proposed to improve GRAPPA is to remove noise from a system identification perspective. In this paper, we first analyze the GRAPPA noise problem from a noisy input-output system perspective; then, a new framework based on errors-in-variables (EIV) model is developed for analyzing noise generation mechanism in GRAPPA and designing a concrete method—instrument variables (IV) GRAPPA to remove noise. The proposed EIV framework provides possibilities that noiseless GRAPPA reconstruction could be achieved by existing methods that solve EIV problem other than IV method. Experimental results show that the proposed reconstruction algorithm can better remove the noise compared to the conventional GRAPPA, as validated with both of phantom and in vivo brain data. PMID:28197419

  15. Embedded Acoustic Sensor Array for Engine Fan Noise Source Diagnostic Test: Feasibility of Noise Telemetry via Wireless Smart Sensors

    Science.gov (United States)

    Zaman, Afroz; Bauch, Matthew; Raible, Daniel

    2011-01-01

    Aircraft engines have evolved into a highly complex system to meet ever-increasing demands. The evolution of engine technologies has primarily been driven by fuel efficiency, reliability, as well as engine noise concerns. One of the sources of engine noise is pressure fluctuations that are induced on the stator vanes. These local pressure fluctuations, once produced, propagate and coalesce with the pressure waves originating elsewhere on the stator to form a spinning pressure pattern. Depending on the duct geometry, air flow, and frequency of fluctuations, these spinning pressure patterns are self-sustaining and result in noise which eventually radiate to the far-field from engine. To investigate the nature of vane pressure fluctuations and the resulting engine noise, unsteady pressure signatures from an array of embedded acoustic sensors are recorded as a part of vane noise source diagnostics. Output time signatures from these sensors are routed to a control and data processing station adding complexity to the system and cable loss to the measured signal. "Smart" wireless sensors have data processing capability at the sensor locations which further increases the potential of wireless sensors. Smart sensors can process measured data locally and transmit only the important information through wireless communication. The aim of this wireless noise telemetry task was to demonstrate a single acoustic sensor wireless link for unsteady pressure measurement, and thus, establish the feasibility of distributed smart sensors scheme for aircraft engine vane surface unsteady pressure data transmission and characterization.

  16. HTGR fuel and fuel cycle technology

    Energy Technology Data Exchange (ETDEWEB)

    Lotts, A.L.; Coobs, J.H.

    1976-08-01

    The status of fuel and fuel cycle technology for high-temperature gas-cooled reactors (HTGRs) is reviewed. The all-ceramic core of the HTGRs permits high temperatures compared with other reactors. Core outlet temperatures of 740/sup 0/C are now available for the steam cycle. For advanced HTGRs such as are required for direct-cycle power generation and for high-temperature process heat, coolant temperatures as high as 1000/sup 0/C may be expected. The paper discusses the variations of HTGR fuel designs that meet the performance requirements and the requirements of the isotopes to be used in the fuel cycle. Also discussed are the fuel cycle possibilities, which include the low-enrichment cycle, the Th-/sup 233/U cycle, and plutonium utilization in either cycle. The status of fuel and fuel cycle development is summarized.

  17. Noise Emission from Laboratory Air Blowers

    Science.gov (United States)

    Rossing, Thomas D.; Windham, Betty

    1978-01-01

    Product noise ratings for a number of laboratory air blowers are reported and several recommendations for reducing laboratory noise from air blowers are given. Relevant noise ratings and methods for measuring noise emission of appliances are discussed. (BB)

  18. Impact of Aviation Fuel Quality on Flight Safety and Environment

    Directory of Open Access Journals (Sweden)

    A.V. Yakovleva

    2013-07-01

    Full Text Available The role of aviation fuels quality for provision of flight safety is described. Statistics on jet fuel consumption all over the world and Ukraine in particular is presented. Analysis of flight accidents is done; the role of fuel quality as a reason of such events as well as a factor affecting the environment is investigated.

  19. A method for limitation of probability of accumulation of fuel elements claddings damage in WWER

    OpenAIRE

    Sergey N. Pelykh; Mark V. Nikolsky; S. D. Ryabchikov

    2014-01-01

    The aim is to reduce the probability of accumulation of fuel elements claddings damage by developing a method to control the properties of the fuel elements on stages of design and operation of WWER. An averaged over the fuel assembly WWER-1000 fuel element is considered. The probability of depressurization of fuel elements claddings is found. The ability to predict the reliability of claddings by controlling the factors that determine the properties of the fuel elements is proved. The expedi...

  20. Genetic noise control via protein oligomerization

    Energy Technology Data Exchange (ETDEWEB)

    Ghim, C; Almaas, E

    2008-06-12

    Gene expression in a cell entails random reaction events occurring over disparate time scales. Thus, molecular noise that often results in phenotypic and population-dynamic consequences sets a fundamental limit to biochemical signaling. While there have been numerous studies correlating the architecture of cellular reaction networks with noise tolerance, only a limited effort has been made to understand the dynamical role of protein-protein associations. We have developed a fully stochastic model for the positive feedback control of a single gene, as well as a pair of genes (toggle switch), integrating quantitative results from previous in vivo and in vitro studies. In particular, we explicitly account for the fast protein binding-unbinding kinetics, RNA polymerases, and the promoter/operator sequences of DNA. We find that the overall noise-level is reduced and the frequency content of the noise is dramatically shifted to the physiologically irrelevant high-frequency regime in the presence of protein dimerization. This is independent of the choice of monomer or dimer as transcription factor and persists throughout the multiple model topologies considered. For the toggle switch, we additionally find that the presence of a protein dimer, either homodimer or heterodimer, may significantly reduce its intrinsic switching rate. Hence, the dimer promotes the robust function of bistable switches by preventing the uninduced (induced) state from randomly being induced (uninduced). The specific binding between regulatory proteins provides a buffer that may prevent the propagation of fluctuations in genetic activity. The capacity of the buffer is a non-monotonic function of association-dissociation rates. Since the protein oligomerization per se does not require extra protein components to be expressed, it provides a basis for the rapid control of intrinsic or extrinsic noise. The stabilization of phenotypically important toggle switches, and nested positive feedback loops in

  1. Effects of Fuel Quantity on Soot Formation Process for Biomass-Based Renewable Diesel Fuel Combustion

    KAUST Repository

    Jing, Wei

    2016-12-01

    Soot formation process was investigated for biomass-based renewable diesel fuel, such as biomass to liquid (BTL), and conventional diesel combustion under varied fuel quantities injected into a constant volume combustion chamber. Soot measurement was implemented by two-color pyrometry under quiescent type diesel engine conditions (1000 K and 21% O2 concentration). Different fuel quantities, which correspond to different injection widths from 0.5 ms to 2 ms under constant injection pressure (1000 bar), were used to simulate different loads in engines. For a given fuel, soot temperature and KL factor show a different trend at initial stage for different fuel quantities, where a higher soot temperature can be found in a small fuel quantity case but a higher KL factor is observed in a large fuel quantity case generally. Another difference occurs at the end of combustion due to the termination of fuel injection. Additionally, BTL flame has a lower soot temperature, especially under a larger fuel quantity (2 ms injection width). Meanwhile, average soot level is lower for BTL flame, especially under a lower fuel quantity (0.5 ms injection width). BTL shows an overall low sooting behavior with low soot temperature compared to diesel, however, trade-off between soot level and soot temperature needs to be carefully selected when different loads are used.

  2. Turbine Fuel Alternatives (Near Term)

    Science.gov (United States)

    1989-10-01

    There was some evidence that the use of the alcohol blends affected the combustion properties of the fuel. A temperature survey was conducted with a T-34C...Jet-A. Also, the corrected fuel flow is lower when using an alcohol blend than when operating on Jet-A. These two factors indicate the combustion ...VERSUS CORRECTED TURBINE OUTLET TEMPERATURE A-7 200, -T ’go-I 190 170- ETA oix 15X ETANOL ! ¶,0-1 1 20- S 110j 1. 001 9 0 I 7 0 10 zo 460 500 540 580

  3. Calibration of an audio frequency noise generator

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1966-01-01

    A noise generator of known output is very convenient in noise measurement. At low audio frequencies, however, all devices, including noise sources, may be affected by excess noise (1/f noise). It is therefore very desirable to be able to check the spectral density of a noise source before it is u...

  4. Progress Scored by CAS in Fuel Cell Engine and Hydrogen Energy Technology

    Institute of Scientific and Technical Information of China (English)

    Zhang Huamin

    2004-01-01

    @@ The fuel cell is an energy conversion device, in which the energy stored in fuel and oxidant is transformed into electricity and heat energy via electrochemical reactions. It has the advantage of high energy transform efficiency, low noise and environmental friendliness. It can also achieve energy supply diversity.

  5. Dynamical decoupling noise spectroscopy

    CERN Document Server

    Alvarez, Gonzalo A

    2011-01-01

    Decoherence is one of the most important obstacles that must be overcome in quantum information processing. It depends on the qubit-environment coupling strength, but also on the spectral composition of the noise generated by the environment. If the spectral density is known, fighting the effect of decoherence can be made more effective. Applying sequences of inversion pulses to the qubit system, we generate effective filter functions that probe the environmental spectral density. Comparing different pulse sequences, we recover the complete spectral density function and distinguish different contributions to the overall decoherence.

  6. Noise hazard course

    CERN Multimedia

    2003-01-01

    A 1/2 day course to promote awareness of the risks incurred by noise at the work place and recommendations to settle them. Next course Wednesday 24th September 2003. Costs are covered by TIS, Jacques Coillard from Bureau Véritas will present the course. Registration is obligatory. For more information and to enrol on this course go to the safety section of Human Resources Training and Development web pages, or contact : Ana-Paula Bernardes/TIS-GS (71385) or e-mail Ana-Paula.Bernardes@cern.ch

  7. Noise hazard course

    CERN Multimedia

    2003-01-01

    A 1/2 day course to promote awareness of the risks incurred by noise at the work place and recommendations to settle them. Next course Wednesday 24th September 2003. Costs are covered by TIS, Jacques Coillard from Bureau Véritas will present the course. Registration is obligatory. For more information and to enrol on this course go to the safety section of Human Resources Training and Development web pages, or contact: Ana-Paula Bernardes/TIS-GS (71385) or e-mail Ana-Paula.Bernardes@cern.ch

  8. Thermal analysis of IRT-T reactor fuel elements

    OpenAIRE

    Naymushin, Artem Georgievich; Chertkov, Yuri Borisovich; Lebedev, Ivan Igorevich; Anikin, Mikhail Nikolaevich

    2015-01-01

    The article describes the method and results of thermo-physical calculations of IRT-T reactor core. Heat fluxes, temperatures of cladding, fuel meat and coolant were calculated for height of core, azimuth directions of FA and each fuel elements in FA. Average calculated values of uniformity factor of energy release distribution for height of fuel assemblies were shown in this research. Onset nucleate boiling temperature and ONB-ratio were calculated. Shows that temperature regimes of fuel ele...

  9. Adaptive neuro-fuzzy methodology for noise assessment of wind turbine.

    Science.gov (United States)

    Shamshirband, Shahaboddin; Petković, Dalibor; Hashim, Roslan; Motamedi, Shervin

    2014-01-01

    Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD) could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.

  10. Adaptive neuro-fuzzy methodology for noise assessment of wind turbine.

    Directory of Open Access Journals (Sweden)

    Shahaboddin Shamshirband

    Full Text Available Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS. This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.

  11. Research on Processing Multi-noise Signals in Mobile Multimedia Communication Based on HFC

    Institute of Scientific and Technical Information of China (English)

    ZENG Qinghui; HU Xiulin; ZHUANG Zhaowen; ZENG Yilin; MA Tao; ZHANG Yunyu; YANG Haizhou

    2001-01-01

    As well known, noise is one of mainobjects of signals processing. However, many kindsof noises are affecting widely on mobile communica-tion along with enlarging mobile networks and rapidlyincreasing application range of multimedia commu-nication. The noises include 1/f noise; burst noise;multichannel noise; thermal and shot noise etc., allof which here are called "multi-noise (MN)" and atthe same time, the signals affected by "multi-noise"is called "multi-noise signals". The article firstly ana-lyzes some disturbance factors of multi-noise that af-fects multimedia flow. Then, it describes briefly hi-erarchical fuzzy control (HFC) technology and its ap-plication procedure for online identification and con-trolling multi-noise signals in mobile multimedia com-munication networks. Lastly, how to make a specialhierarchical fuzzy control program is also discussed.With different test examples, the article demonstratesthe ability of hierarchical fuzzy control to identifyflow states and control signal distortion in multime-dia communication. The hierarchical fuzzy controland hierarchical fuzzy control programs provide anadvanced efficient tool for supervising the distributedstates of multi-noise and movement characteristics ofmulti-noise signals in mobile multimedia communica-tion.

  12. Monitoring of Noise During Ganeshotsav

    Directory of Open Access Journals (Sweden)

    Mrs. P. Saler

    2011-09-01

    Full Text Available Sound is a form of energy emitted by a vibrating body causing change in pressure of the surrounding elastic medium through which energy is transmitted. Noise has been defined as unwanted sound. Noise is a disturbance to the human environment which is escalating at a high rate. There are numerous effects of noise on human and environment due to the increase in noise pollution slowly, insensibly; we seem to accept noise and the physiological and psychological deterioration that accompanies it as an inevitable part of our lives. Althoughattempts have been made to regulate noise pollution by setting standards for some of the major sources of noise, we often are unable to monitor them. One such source of noise in India is celebration of festival and especially in Maharashtra, the biggest festival- Ganeshostav. The way noise levels are increasing year by year during this festival, it seems we enjoy these sounds, though it has harmful effects on Human Health and Environment. This paper focuses on study of noise pollution during Ganesh Festival and also its other causes and effects.

  13. Occupational noise in printing companies.

    Science.gov (United States)

    Mihailovic, Aleksandra; Grujic, Selena D; Kiurski, Jelena; Krstic, Jelena; Oros, Ivana; Kovacevic, Ilija

    2011-10-01

    The extent of noise in five printing companies in Novi Sad, Serbia, was determined using TES-1358A Sound Analyzer with RS-232 Interface. The data on equivalent A-level (dBA), as well as, maximum and minimum sound pressure levels were collected. It was found that folders and offset printing units are the predominant noise sources, with the average L (eq) levels of 87.66 and 82.7 dBA, respectively. Forty percent of the machines produced noise levels above the limiting threshold level of 85 dBA, allowed by law. The noise in all printing companies was dominated by higher frequency noise, and the maximum level mostly appeared at 4,000 Hz. For offset printing machines and folders, the means of L (eq) levels exceeded the permissible levels given by NR-80 curve at higher frequencies. There are no published studies of occupational noise and hearing impairment of workers exposed to hazardous noise in printing industry in Serbia. More extensive studies are needed to determine the exact impact of noise on the workers. Technical and organizational measures in order to control noise and prevent noise exposure, and general hearing conservation program to protect workers, should be introduced in printing industry.

  14. On Physical Aeroacoustics with Some Implications for Low-Noise Aircraft Design and Airport Operations

    Directory of Open Access Journals (Sweden)

    Luís M. B. C. Campos

    2015-02-01

    Full Text Available Air traffic is growing at a steady rate of 3% to 5% per year in most regions of the world, implying a doubling every 15–25 years. This requires major advances in aircraft noise reduction at airports, just not to increase the noise exposure due to the larger number of aircraft movements. In fact it can be expected, as a consequence of increased opposition to noise by near airport residents, that the overall noise exposure will have to be reduced, by bans, curfews, fines, and other means and limitations, unless significantly quieter aircraft operations are achieved. The ultimate solution is aircraft operations inaudible outside the airport perimeter, or noise levels below road traffic and other existing local noise sources. These substantial noise reductions cannot come at the expense of a degradation of cruise efficiency, that would affect not just economics and travel time, but would increase fuel consumption and emission of pollutants on a global scale. The paper reviews the: (i current knowledge of the aircraft noise sources; (ii the sound propagation in the atmosphere and ground effects that determine the noise annoyance of near-airport residents; (iii the noise mitigation measures that can be applied to current and future aircraft; (iv the prospects of evolutionary and novel aircraft designs towards quieter aircraft in the near term and eventually to operations inaudible outside the airport perimeter. The 20 figures and 1 diagram with their legends provide a visual summary of the review.

  15. Neurally based measurement and evaluation of environmental noise

    CERN Document Server

    Soeta, Yoshiharu

    2015-01-01

    This book deals with methods of measurement and evaluation of environmental noise based on an auditory neural and brain-oriented model. The model consists of the autocorrelation function (ACF) and the interaural cross-correlation function (IACF) mechanisms for signals arriving at the two ear entrances. Even when the sound pressure level of a noise is only about 35 dBA, people may feel annoyed due to the aspects of sound quality. These aspects can be formulated by the factors extracted from the ACF and IACF. Several examples of measuring environmental noise—from outdoor noise such as that of aircraft, traffic, and trains, and indoor noise such as caused by floor impact, toilets, and air-conditioning—are demonstrated. According to the noise measurement and evaluation, applications for sound design are discussed. This book provides an excellent resource for students, researchers, and practitioners in a wide range of fields, such as the automotive, railway, and electronics industries, and soundscape, architec...

  16. A simple method for NMR t1 noise suppression

    Science.gov (United States)

    Mo, Huaping; Harwood, John S.; Yang, Danzhou; Post, Carol Beth

    2017-03-01

    t1 noise appears as random or semi-random spurious streaks along the indirect t1 (F1) dimension of a 2D or nD NMR spectrum. It can significantly downgrade spectral quality, especially for spectra with strong diagonal signals such as NOESY, because useful and weak cross-peaks can be easily buried under t1 noise. One of the significant contributing factors to t1 noise is unwanted and semi-random F2 signal modulation during t1 acquisition. As such, t1 noise from different acquisitions is unlikely to correlate with each other strongly. In the case of NOESY, co-addition of multiple spectra significantly reduces t1 noise compared with conventional acquisition with the same amount of total acquisition time and resolution.

  17. International Space Station Noise Constraints Flight Rule Process

    Science.gov (United States)

    Limardo, Jose G.; Allen, Christopher S.; Danielson, Richard W.

    2014-01-01

    Crewmembers onboard the International Space Station (ISS) live in a unique workplace environment for as long as 6 -12 months. During these long-duration ISS missions, noise exposures from onboard equipment are posing concerns for human factors and crewmember health risks, such as possible reductions in hearing sensitivity, disruptions of crew sleep, interference with speech intelligibility and voice communications, interference with crew task performance, and reduced alarm audibility. The purpose of this poster is to describe how a recently-updated noise constraints flight rule is being used to implement a NASA-created Noise Exposure Estimation Tool and Noise Hazard Inventory to predict crew noise exposures and recommend when hearing protection devices are needed.

  18. How to encourage road noise abatement in Nordic municipalities

    DEFF Research Database (Denmark)

    Sørensen, Claus Hedegaard

    2008-01-01

    municipalities actively provide and implement road noise abatement measures in situations of existent residential areas and roads. For the municipal organisation, regularly mapping the noise problem and making status reports of the achievements are very important. Civil servants should also use any opportunity...... to already existing residential areas and roads is: which conditions in the municipal organisation and its institutional environment contribute to making municipalities provide and implement noise abatement measures? Th e assumption is that three factors infl uence how the municipalities prioritize among...... political issues: the municipal organisation itself, the local institutional environment (citizens, business and NGOs), and the state and trans-municipal networks. A study of the anatomy of municipal road noise abatement policy shows that conditions for implementing road noise abatement in existing...

  19. GHz bandwidth noise eater hybrid optical amplifier: design guidelines.

    Science.gov (United States)

    Danion, Gwennaël; Bondu, François; Loas, Goulc'hen; Alouini, Mehdi

    2014-07-15

    This Letter describes the design of an optical amplifier system optimized to reduce the relative intensity noise (RIN) of the input signal, and discloses its performance in terms of intensity noise reduction and bandwidth, without phase noise degradation. This polarization-maintaining amplifier is composed of an erbium-doped fiber amplifier (EDFA) cascaded with a semiconductor optical amplifier (SOA). The EDFA is sized to feed the SOA with a constant power corresponding to the optimal saturation level for noise reduction, through coherent population oscillations. When properly optimized, such an amplifier provides, simultaneously, 17 dB optical gain, 5.4 dB noise factor, and 20 dB reduction of the input-RIN across a 3 GHz bandwidth, without any electronics feedback loop.

  20. Thermal noise free opto-mechanics using strong optical springs

    CERN Document Server

    Page, Michael; Zhao, Chunnong; Blair, David; Ju, Li; Pan, Huang-Wei; Chao, Shiuh; Mitrofanov, Valery; Sadeghian, Hamed

    2016-01-01

    Thermal noise generally greatly exceeds quantum noise in optomechanical devices unless the mechanical frequency is very high or the thermodynamic temperature is very low. This paper addresses the design concept for a novel optomechanical device capable of ultrahigh quality factors with negligible thermal noise. The proposed system consists of a minimally supported millimeter scale pendulum mounted in a Double End-Mirror Sloshing (DEMS) cavity that is topologically equivalent to a Membrane-in-the-Middle (MIM) cavity. The radiation pressure inside the high-finesse cavity allows for high optical stiffness, cancellation of terms which lead to unwanted negative damping and suppression of quantum radiation pressure noise. We solve for the optical spring dynamics of the system using the Hamiltonian, find the noise spectral density and show that stable optical trapping is possible. We also assess various loss mechanisms, one of the most important being the acceleration loss due to the optical spring. We show that pra...

  1. Development of Active Noise Control System for Quieting Transformer Noise

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bok Kyu; Song, Seik Young; Choi, Huo Yul [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Yun, Dae Hea; Lee, Hyuk Jae [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

    1997-12-31

    The passive noise control technique made use of sound-absorbing or soundproofing materials, so it required a large area and high cost for installation and had a drawback of poor performance at low frequency. Compared to this, the Active Noise Control attenuates noise sound pressure by using secondary source which has same performance ay low-frequency. Furthermore, it is able to save space and expenses. - research on adaptive algorithms - evaluation of global attenuation of the control - computer simulation - real-time Active Noise Control System Hardware Implementation - ANC system setting in the noisy area.

  2. Development of Active Noise Control System for Quieting Transformer Noise

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bok Kyu; Song, Seik Young; Choi, Huo Yul [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Yun, Dae Hea; Lee, Hyuk Jae [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

    1997-12-31

    The passive noise control technique made use of sound-absorbing or soundproofing materials, so it required a large area and high cost for installation and had a drawback of poor performance at low frequency. Compared to this, the Active Noise Control attenuates noise sound pressure by using secondary source which has same performance ay low-frequency. Furthermore, it is able to save space and expenses. - research on adaptive algorithms - evaluation of global attenuation of the control - computer simulation - real-time Active Noise Control System Hardware Implementation - ANC system setting in the noisy area.

  3. Thermionic fuel element technology status

    Science.gov (United States)

    Holland, J. W.; Horner, M. W.; Yang, L.

    1985-01-01

    The results of research, conducted between the mid-1960s and 1973, on the multiconverter thermionic fuel elements (TFEs) that comprise the reactor core of an SP-100 thermionic reactor system are presented. Fueled-emitter technology, insulator technology and cell and TFE assembly technology of the prototypical TFEs which were tested in-pile and out-of-pile during these years are described. The proto-TFEs have demonstrated reproducible performance within 5 percent and no premature failures within the 1.5 yr of operation (with projected 3-yr lifetimes). The two primary life-limiting factors had been identified as thermionic emitter dimensional increase due to interactions with the fuel and electrical insulator structural damage from fast neutrons. Multiple options for extending TFE lifetimes to 7 yr or longer are available and will be investigated in the 1984-1985 SP-100 program for resolution of critical technology issues. Design diagrams and test graphs are included.

  4. Decoherence from 1/f Flux Noise

    Science.gov (United States)

    2014-12-30

    separate experiment, they have suppressed the surface spin susceptibility by a factor of 3 by enclosing the sample in an evacuated hermetic cell and...noise in this cell. Finally, they have begun to investigate possible magnetic contributions to high- frequency loss . For a typical coplanar geometry, the...magnetic participation ratio of a ~ 1 nm layer of adsorbed molecular oxygen is around 10-4, of the same order as the dielectric participation ratio

  5. Near-ambient solid polymer fuel cell

    Science.gov (United States)

    Holleck, G. L.

    1993-01-01

    Fuel cells are extremely attractive for extraterrestrial and terrestrial applications because of their high energy conversion efficiency without noise or environmental pollution. Among the various fuel cell systems the advanced polymer electrolyte membrane fuel cells based on sulfonated fluoropolymers (e.g., Nafion) are particularly attractive because they are fairly rugged, solid state, quite conductive, of good chemical and thermal stability and show good oxygen reduction kinetics due to the low specific adsorption of the electrolyte on the platinum catalyst. The objective of this program is to develop a solid polymer fuel cell which can efficiently operate at near ambient temperatures without ancillary components for humidification and/or pressurization of the fuel or oxidant gases. During the Phase 1 effort we fabricated novel integral electrode-membrane structures where the dispersed platinum catalyst is precipitated within the Nafion ionomer. This resulted in electrode-membrane units without interfacial barriers permitting unhindered water diffusion from cathode to anode. The integral electrode-membrane structures were tested as fuel cells operating on H2 and O2 or air at 1 to 2 atm and 10 to 50 C without gas humidification. We demonstrated that cells with completely dry membranes could be self started at room temperature and subsequently operated on dry gas for extended time. Typical room temperature low pressure operation with unoptimized electrodes yielded 100 mA/cm(exp 2) at 0.5V and maximum currents over 300 mA/cm(exp 2) with low platinum loadings. Our results clearly demonstrate that operation of proton exchange membrane fuel cells at ambient conditions is feasible. Optimization of the electrode-membrane structure is necessary to assess the full performance potential but we expect significant gains in weight and volume power density for the system. The reduced complexity will make fuel cells also attractive for smaller and portable power supplies and as

  6. Mathematical modeling of polymer electrolyte fuel cells

    Science.gov (United States)

    Sousa, Ruy; Gonzalez, Ernesto R.

    Fuel cells with a polymer electrolyte membrane have been receiving more and more attention. Modeling plays an important role in the development of fuel cells. In this paper, the state-of-the-art regarding modeling of fuel cells with a polymer electrolyte membrane is reviewed. Modeling has allowed detailed studies concerning the development of these cells, e.g. in discussing the electrocatalysis of the reactions and the design of water-management schemes to cope with membrane dehydration. Two-dimensional models have been used to represent reality, but three-dimensional models can cope with some important additional aspects. Consideration of two-phase transport in the air cathode of a proton exchange membrane fuel cell seems to be very appropriate. Most fuel cells use hydrogen as a fuel. Besides safety concerns, there are problems associated with production, storage and distribution of this fuel. Methanol, as a liquid fuel, can be the solution to these problems and direct methanol fuel cells (DMFCs) are attractive for several applications. Mass transport is a factor that may limit the performance of the cell. Adsorption steps may be coupled to Tafel kinetics to describe methanol oxidation and methanol crossover must also be taken into account. Extending the two-phase approach to the DMFC modeling is a recent, important point.

  7. Simulation of realistic instrument noise for GRACE follow-on.

    Science.gov (United States)

    Ellmer, Matthias; Mayer-Gürr, Torsten

    2014-05-01

    Computer simulations have been an indispensable tool in assessing and predicting the performance of gravity recovery satellite missions, both present and future. Future satellite missions like GRACE follow-on will measure Earth's gravity with a much higher precision than their predecessors. This increased precision makes it necessary to reevaluate the applicability of current simulation strategies to future gravity missions. In past simulation efforts, effects that are known to be relevant factors for mission performance are often approximated or modeled incompletely. One such effect is the noise applied to simulated observables like precise orbits or K-Band ranges. These noisy observables are generated by adding simple white noise of a specific power to noise-free raw measurements. The noisy observables are then used in closed-loop simulations to quantify the performance of specific instruments, or a mission scenario as a whole. This work presents strategies to generate more realistic noise for satellite missions as implemented in the GROOPS (Gravity Recovery Object Orientated Programming System) software package. A generic interface for different noise generators is implemented in GROOPS. This interface is used to add different types of noise, such as white noise, colored or correlated noise, or noise with a given power spectral density to generated observables. It is thus possible to study the effect of the chosen noise model on the generated observable, and conversely the recovered gravity field as a whole. A better knowledge of the noise characteristics of the instruments on GRACE and GRACE follow-on will allow us to improve our understanding of their complex interactions. It will also allow us to improve our processing strategies for both simulated and real data, and will thus lead to a more precise and better understood recovered gravity field.

  8. Measurement and Assessment of Noise Within Passenger Trains

    Science.gov (United States)

    HARDY, A. E. J.

    2000-03-01

    Railways are becoming increasingly market-driven. Consequently, it is important that passengers are provided with a comfortable environment that reflects the operator's desired image for the service. A major factor in determining how passengers perceive the environment within trains is the level and nature of sound to which they are exposed. Unfortunately, the subject of noise within railway vehicles has had less attention in recent years, and is therefore less well developed, than external “environmental” noise. Two specific areas that merit investigation are methods for its quantification and assessment. A variety of criteria are used for assessing the noise environment within buildings, and may be considered appropriate for the quantification of internal train noise. These include “noise criteria” (NC), “preferred noise criteria” (PNC), “noise rating” (NR), and “room criterion” (RC). Recently, the automotive industry has also been using loudness level. Simple descriptors, such as the A-weighted sound level, have not been found to correlate well with perceived acoustic comfort. A complicating factor when considering internal rail vehicle noise is that its level and quality is not constant, with significant variability likely to occur over the duration of a journey. This difficulty is compounded by acoustic spatial variation within a vehicle. The paper considers the problems inherent in the quantification of noise within rail vehicles, and in the determination of the relationship between this noise and passenger response. Methods by which these problems may be overcome are discussed, drawing on real data and on long experience of study in this field.

  9. HTGR Fuel performance basis

    Energy Technology Data Exchange (ETDEWEB)

    Shamasundar, B.I.; Stansfield, O.M.; Jensen, D.D.

    1982-05-01

    The safety characteristics of the high-temperature gas-cooled reactor (HTGR) during normal and accident conditions are determined in part by HTGR fuel performance. During normal operation, less than 0.1% fuel failure occurs, primarily from defective particles. This low fuel failure fraction limits circulating activity to acceptable levels. During severe accidents, the radiological consequence is influenced by high-temperature fuel particle behavior. An empirical fuel failure model, supported by recent experimental data, is presented. The onset of significant fuel particle failure occurs at temperatures in excess of 1600/sup 0/C, and complete fuel failure occurs at 2660/sup 0/C. This indicates that the fuel is more retentive at higher temperatures than previously assumed. The more retentive nature of the fuel coupled with the high thermal capacitance of the core results in slow release of fission products from the core during severe accidents.

  10. Analysis of nuclear characteristics and fuel economics for PWR core with homogeneous thorium fuels

    Energy Technology Data Exchange (ETDEWEB)

    Joo, H. K.; Noh, J. M.; Yoo, J. W.; Song, J. S.; Kim, J. C.; Noh, T. W

    2000-12-01

    The nuclear core characteristics and economics of an once-through homogenized thorium cycle for PWR were analyzed. The lattice code, HELIOS has been qualified against BNL and B and W critical experiments and the IAEA numerical benchmark problem in advance of the core analysis. The infinite multiplication factor and the evolution of main isotopes with fuel burnup were investigated for the assessment of depletion charateristics of thorium fuel. The reactivity of thorium fuel at the beginning of irradiation is smaller than that of uranium fuel having the same inventory of {sup 235}U, but it decrease with burnup more slowly than in UO{sub 2} fuel. The gadolinia worth in thorium fuel assembly is also slightly smaller than in UO{sub 2} fuel. The inventory of {sup 233}U which is converted from {sup 232}Th is proportional to the initial mass of {sup 232}Th and is about 13kg per one tones of initial heavy metal mass. The followings are observed for thorium fuel cycle compared with UO{sub 2} cycle ; shorter cycle length, more positive MTC at EOC, more negative FTC, similar boron worth and control rod. Fuel economics of thorium cycle was analyzed by investigating the natural uranium requirements, the separative work requirements, and the cost for burnable poison rods. Even though less number of burnable poison rods are required in thorium fuel cycle, the costs for the natural uranium requirements and the separative work requirements are increased in thorium fuel cycle. So within the scope of this study, once through cycle concept, homogenized fuel concept, the same fuel management scheme as uranium cycle, the thorium fuel cycle for PWR does not have any economic incentives in preference to uranium.

  11. Fuels Combustion Research: Supercritical Fuel Pyrolysis

    National Research Council Canada - National Science Library

    Glassman, Irvin

    2001-01-01

    Present and anticipated variation in jet propulsion fuels due to advanced engine compression ratios and airframe cooling requirements necessitate greater understanding of chemical phenomena associated...

  12. Fuels Combustion Research: Supercritical Fuel Pyrolysis

    National Research Council Canada - National Science Library

    Glassman, Irvin

    2000-01-01

    Present and anticipated variation in jet propulsion fuels due to advanced engine compression ratios and airframe cooling requirements necessitate greater understanding of chemical phenomena associated...

  13. Noise in Lead Beta Alumina.

    Science.gov (United States)

    1987-05-01

    single crystal and ceramic samples. The temperature dependance for diffusion noise (I>O,1OHz) is greater than can be accounted for by Equation (1). This...3.2 3.3 3.4 3.5 3.6 3.7 1000/T IN 1/9 Figure 2. Temperature Dependance of Nyqutst Noise (5kHz) and Diffusion Noise (lOHz) of Single Crystal and

  14. Noise of sliding rough contact

    Science.gov (United States)

    Le Bot, Alain

    2017-01-01

    This article is a discussion about the origin of friction noise produced when rubbing solids having rough surfaces. We show that noise emerges from numerous impacts into the contact between antagonist asperities of surfaces. Prediction of sound sources reduces to a statistical problem of contact mechanics. On the other hand, contact is also responsible of dissipation of vibration. This leads to the paradoxical result that the noise may not be proportional to the number of sources.

  15. Status: Crewmember Noise Exposures on the International Space Station

    Science.gov (United States)

    Limardo-Rodriguez, Jose G.; Allen, Christopher S.; Danielson, Richard W.

    2015-01-01

    The International Space Station (ISS) provides a unique environment where crewmembers from the US and our international partners work and live for as long as 6 to 12 consecutive months. During these long-durations ISS missions, noise exposures from onboard equipment are posing concerns for human factors and crewmember health risks, such as possible reductions in hearing sensitivity, disruptions of crew sleep, interference with speech intelligibility and voice communications, interference with crew task performance, and reduced alarm audibility. It is crucial to control acoustical noise aboard ISS to acceptable noise exposure levels during the work-time period, and to also provide a restful sleep environment during the sleep-time period. Acoustic dosimeter measurements, obtained when the crewmember wears the dosimeter for 24-hour periods, are conducted onboard ISS every 60 days and compared to ISS flight rules. NASA personnel then assess the acoustic environment to which the crewmembers are exposed, and provide recommendations for hearing protection device usage. The purpose of this paper is to provide an update on the status of ISS noise exposure monitoring and hearing conservation strategies, as well as to summarize assessments of acoustic dosimeter data collected since the Increment 36 mission (April 2013). A description of the updated noise level constraints flight rule, as well as the Noise Exposure Estimation Tool and the Noise Hazard Inventory implementation for predicting crew noise exposures and recommending to ISS crewmembers when hearing protection devices are required, will be described.

  16. Analysis and removing noise from speech using wavelet transform

    Science.gov (United States)

    Tomala, Karel; Voznak, Miroslav; Partila, Pavol; Rezac, Filip; Safarik, Jakub

    2013-05-01

    The paper discusses the use of Discrete Wavelet Transform (DWT) and Stationary Wavelet Transform (SWT) wavelet in removing noise from voice samples and evaluation of its impact on speech quality. One significant part of Quality of Service (QoS) in communication technology is the speech quality assessment. However, this part is seriously overlooked as telecommunication providers often focus on increasing network capacity, expansion of services offered and their enforcement in the market. Among the fundamental factors affecting the transmission properties of the communication chain is noise, either at the transmitter or the receiver side. A wavelet transform (WT) is a modern tool for signal processing. One of the most significant areas in which wavelet transforms are used is applications designed to suppress noise in signals. To remove noise from the voice sample in our experiment, we used the reference segment of the voice which was distorted by Gaussian white noise. An evaluation of the impact on speech quality was carried out by an intrusive objective algorithm Perceptual Evaluation of Speech Quality (PESQ). DWT and SWT transformation was applied to voice samples that were devalued by Gaussian white noise. Afterwards, we determined the effectiveness of DWT and SWT by means of objective algorithm PESQ. The decisive criterion for determining the quality of a voice sample once the noise had been removed was Mean Opinion Score (MOS) which we obtained in PESQ. The contribution of this work lies in the evaluation of efficiency of wavelet transformation to suppress noise in voice samples.

  17. Jet Engine Noise Generation, Prediction and Control. Chapter 86

    Science.gov (United States)

    Huff, Dennis L.; Envia, Edmane

    2004-01-01

    Aircraft noise has been a problem near airports for many years. It is a quality of life issue that impacts millions of people around the world. Solving this problem has been the principal goal of noise reduction research that began when commercial jet travel became a reality. While progress has been made in reducing both airframe and engine noise, historically, most of the aircraft noise reduction efforts have concentrated on the engines. This was most evident during the 1950 s and 1960 s when turbojet engines were in wide use. This type of engine produces high velocity hot exhaust jets during takeoff generating a great deal of noise. While there are fewer commercial aircraft flying today with turbojet engines, supersonic aircraft including high performance military aircraft use engines with similar exhaust flow characteristics. The Pratt & Whitney F100-PW-229, pictured in Figure la, is an example of an engine that powers the F-15 and F-16 fighter jets. The turbofan engine was developed for subsonic transports, which in addition to better fuel efficiency also helped mitigate engine noise by reducing the jet exhaust velocity. These engines were introduced in the late 1960 s and power most of the commercial fleet today. Over the years, the bypass ratio (that is the ratio of the mass flow through the fan bypass duct to the mass flow through the engine core) has increased to values approaching 9 for modern turbofans such as the General Electric s GE-90 engine (Figure lb). The benefits to noise reduction for high bypass ratio (HPBR) engines are derived from lowering the core jet velocity and temperature, and lowering the tip speed and pressure ratio of the fan, both of which are the consequences of the increase in bypass ratio. The HBPR engines are typically very large in diameter and can produce over 100,000 pounds of thrust for the largest engines. A third type of engine flying today is the turbo-shaft which is mainly used to power turboprop aircraft and helicopters

  18. Road traffic noise and stroke

    DEFF Research Database (Denmark)

    Sørensen, Mette; Hvidberg, Martin; Andersen, Zorana J

    2011-01-01

    Epidemiological studies suggest that long-term exposure to road traffic noise increases the risk of cardiovascular disorders. The aim of this study was to investigate the relation between exposure to road traffic noise and risk for stroke, which has not been studied before.......Epidemiological studies suggest that long-term exposure to road traffic noise increases the risk of cardiovascular disorders. The aim of this study was to investigate the relation between exposure to road traffic noise and risk for stroke, which has not been studied before....

  19. Noise Pollution and Health Effects

    Directory of Open Access Journals (Sweden)

    Geravandi

    2015-01-01

    Full Text Available Background Noise pollution is of particular importance due to the physical and psychological effects on humans. Noise is a stressor that affects the autonomic nervous system and the endocrine system. Noise is also a threat to marine and terrestrial ecosystems. Health risks from noise are correlated with road traffic. In other words, noise health effects are the health consequences of elevated sound levels. Objectives This study aims to determine the effect of noise pollution (near roadways on health issues in Ahvaz, Iran. Materials and Methods In this cross-sectional study, equivalent sound pressure level were measured by sound level meters TES-1353 in 75 locations around 4 roadways, which had a high load of traffic in Ahvaz City during day time. During the study, 820 measurements were recorded at measuring stations, for 7 days per week with 1-hour interval between each measurement. Statistical analysis was carried out by SPSS software. Results According to the research findings, the equivalent sound pressure levels in all stations were 76.28 ± 3.12 dB (Mean ± SD. According to sound measurements and the survey questionnaire, noise pollution is higher than EPA (US Environmental Protection Agency and Iran standard level. Based on result of this study the worst noise health effects were the nervousness and sleep quality during 2012. Conclusions According to the results of this study, with increasing load of traffic, there is an increasing need for proper consideration plans to control noise pollution and prevent its effects.

  20. Adjusting phenotypes by noise control.

    Directory of Open Access Journals (Sweden)

    Kyung H Kim

    2012-01-01

    Full Text Available Genetically identical cells can show phenotypic variability. This is often caused by stochastic events that originate from randomness in biochemical processes involving in gene expression and other extrinsic cellular processes. From an engineering perspective, there have been efforts focused on theory and experiments to control noise levels by perturbing and replacing gene network components. However, systematic methods for noise control are lacking mainly due to the intractable mathematical structure of noise propagation through reaction networks. Here, we provide a numerical analysis method by quantifying the parametric sensitivity of noise characteristics at the level of the linear noise approximation. Our analysis is readily applicable to various types of noise control and to different types of system; for example, we can orthogonally control the mean and noise levels and can control system dynamics such as noisy oscillations. As an illustration we applied our method to HIV and yeast gene expression systems and metabolic networks. The oscillatory signal control was applied to p53 oscillations from DNA damage. Furthermore, we showed that the efficiency of orthogonal control can be enhanced by applying extrinsic noise and feedback. Our noise control analysis can be applied to any stochastic model belonging to continuous time Markovian systems such as biological and chemical reaction systems, and even computer and social networks. We anticipate the proposed analysis to be a useful tool for designing and controlling synthetic gene networks.

  1. High level white noise generator

    Science.gov (United States)

    Borkowski, Casimer J.; Blalock, Theron V.

    1979-01-01

    A wide band, stable, random noise source with a high and well-defined output power spectral density is provided which may be used for accurate calibration of Johnson Noise Power Thermometers (JNPT) and other applications requiring a stable, wide band, well-defined noise power spectral density. The noise source is based on the fact that the open-circuit thermal noise voltage of a feedback resistor, connecting the output to the input of a special inverting amplifier, is available at the amplifier output from an equivalent low output impedance caused by the feedback mechanism. The noise power spectral density level at the noise source output is equivalent to the density of the open-circuit thermal noise or a 100 ohm resistor at a temperature of approximately 64,000 Kelvins. The noise source has an output power spectral density that is flat to within 0.1% (0.0043 db) in the frequency range of from 1 KHz to 100 KHz which brackets typical passbands of the signal-processing channels of JNPT's. Two embodiments, one of higher accuracy that is suitable for use as a standards instrument and another that is particularly adapted for ambient temperature operation, are illustrated in this application.

  2. 77 FR 699 - Regulation of Fuels and Fuel Additives: Identification of Additional Qualifying Renewable Fuel...

    Science.gov (United States)

    2012-01-05

    ... January 5, 2012 Part V Environmental Protection Agency 40 CFR Part 80 Regulation of Fuels and Fuel Additives: Identification of Additional Qualifying Renewable Fuel Pathways Under the Renewable Fuel Standard... Fuels and Fuel Additives: Identification of Additional Qualifying Renewable Fuel Pathways Under...

  3. The Comparative Analysis of Aversive and Ordinary Noise.

    Science.gov (United States)

    Mobley, C. Marion, Jr.

    There is a vast amount of literature concerning the psychological and physiological effects of ordinary noise on the individual. However, few publications have addressed the analysis of aversive noise. This research analyzes three noises which produce the familiar goose flesh or chilling effect responsivity. These aversive sounds which are made by chalk squeaking on the chalkboard, fingernails on the chalkboard and rubbing styrofoam against a smooth surface are digitally compared to ordinary noise to show how these aversive sounds differ from sounds which are only annoying. This work, which uses Fast Fourier Transform (FFT) analysis is a combination with cross correlation analysis and other innovative methods to produce comparative data on noises, illustrates subtle differences between ordinary and aversive noise which may be useful for future work in acoustics or experimental psychology. The literature review shows disagreement among the numerous works on the effects of ordinary noise on human subjects. One explanation for this difference is the failure to adequately measure and define the dynamic nature of the noise used. The existing literature also establishes that a mixture of tones plus random noise is more annoying (but not aversive) than either the random noise or the tones alone. This investigation shows that one property of aversive noises is the combination of randomness plus tones which vary rapidly with time. This paper utilizes a new digital technique which improves the FFT analyzer resolution by a factor of 25. The resulting +/-2 Hz accuracy facilitated the presentation of frequency variation as a function of time data. Other computer generated graphical data includes the percent harmonic deviation as a function of time, the rate of change of fundamental frequency, and the rate of change in harmonic deviation. From these dynamic data, average values are calculated which show the aversive noise to be consistently greater in mean frequency deviation

  4. A laboratory comparison of emission factors, number size distributions and morphology of ultrafine particles from eleven different household cookstove-fuel systems

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes all data used to generate figures in the manuscript and supporting information for the publication entitled "Emission factors, number size...

  5. Composite nuclear fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    Dollard, W.J.; Ferrari, H.M.

    1982-04-27

    An open lattice elongated nuclear fuel assembly including small diameter fuel rods disposed in an array spaced a selected distance above an array of larger diameter fuel rods for use in a nuclear reactor having liquid coolant flowing in an upward direction. Plenums are preferably provided in the upper portion of the upper smaller diameter fuel rods and in the lower portion of the lower larger diameter fuel rods. Lattice grid structures provide lateral support for the fuel rods and preferably the lowest grid about the upper rods is directly and rigidly affixed to the highest grid about the lower rods.

  6. Neuron dynamics in the presence of 1/f noise

    CERN Document Server

    Sobie, Cameron; de Sousa, Rogerio

    2010-01-01

    We present numerical simulations of the leaky integrate and fire model of the neuron subject to 1/f and other types of noise spectra. The impact of noise is considered on two quantities of interest to neuron function: The spike count Fano factor and the speed of neuron response to a small step-like stimulus. Under 1/f noise, spike dynamics lacks a characteristic correlation time, leading to non-ergodic behavior and Fano factor monotonically increasing as a function of time. We compare our results to experimental data of single neurons in vivo [M.C. Teich et al., J. Opt. Soc. Am. A 14, 529 (1997)], and show how the 1/f noise model provides much better agreement than the usual approximations based on Lorentzian noise. The low frequency noise, however, complicates the case for information coding scheme based on interspike intervals by introducing variability in the neuron response time. On the other hand, the neuron response time to a step stimulus is, remarkably, nearly optimal in the presence of 1/f noise. An ...

  7. A survey of noise-induced hearing impairment in workers of a factory of electrical products in Hangzhou city and its relevant contributing factors%杭州某电器厂工人职业性听力损害调查研究及相关因素分析

    Institute of Scientific and Technical Information of China (English)

    陈旭红

    2014-01-01

    目的:调查研究噪声对杭州地区某电器厂工人听力的影响,并探讨其影响因素。方法采用精密脉冲声级计测定电器厂噪声作业环境的噪声强度,采用听力计检测噪声作业工人的听力状况,测定听力损害罹患率,将听力损害与接噪工龄、工种、性别、年龄进行统计学分析。结果该电器厂噪声性质为中高频连续稳态噪声,平均噪声强度92.34±8.62 dB(A),工人职业性听力损害的罹患率为19.97%,听力损害随接噪工龄增加而升高,各工龄组间比较差异有显著性(P<0.05);不同工种听力损害的检出率由高到低依次为磨工、铆工、冲压、折弯工、总装、剪板、焊接。结论生产性噪声对作业工人的听力损害有显著影响。%Objective To understand the effects of noise on the hearing of workers of an electric appliance plant in Hangzhou and study the contributing factors in order to obtain scientific knowledge of the prevention of noise induced -hearing loss .Method Noise levels were measured using a precision pulse sound level meter .Audiometric tests were conducted with an audiometer , and the prevalence rate was also calculated .Applied statistical method to analyze the relationship between noise-induced hearing impairment and length of service ,type of work ,age and gender .Findings The noise of the plant was mainly intermediate or high frequency , which was continuous and steady .The average noise intensity was 92.34 ±8.62 dB(A).The prevalence rate of occupational noise-induced hearing impairment was 19.97%.The rate of noise-induced hearing impairment increased as length of service increased ,and was significant among different types of work.The attack rate of hearing impairment of all types of work from high to low were grinder , riveter, punching workers, bend workers , assembly workers , clip workers and welders .Conclusion The productive noise has significant impact on

  8. Physiological, Psychological, and Social Effects of Noise

    Science.gov (United States)

    Kryter, K. D.

    1984-01-01

    The physiological, and behavioral effects of noise on man are investigated. Basic parameters such as definitions of noise, measuring techniques of noise, and the physiology of the ear are presented prior to the development of topics on hearing loss, speech communication in noise, social effects of noise, and the health effects of noise pollution. Recommendations for the assessment and subsequent control of noise is included.

  9. Annoyance due to simulated blade-slap noise

    Science.gov (United States)

    Powell, C. A.

    1978-01-01

    The effects of several characteristics of blade slap noise on annoyance response were studied. These characteristics or parameters were the sound pressure level of the continuous noise used to simulate helicopter broadband noise, the ratio of impulse peak to broadband noise or crest factor, the number of pressure excursions comprising an impulse event, the rise and fall time of the individual impulses, and the repetition frequency of the impulses. Analyses were conducted to determine the correlation between subjective response and various physical measures for the range of parameters studied. A small but significant improvement in the predictive ability of PNL was provided by an A-weighted crest factor correlation. No significant improvement in predictive ability was provided by a rate correction.

  10. Noise-induced synchronization, desynchronization, and clustering in globally coupled nonidentical oscillators

    KAUST Repository

    Lai, Yi Ming

    2013-07-09

    We study ensembles of globally coupled, nonidentical phase oscillators subject to correlated noise, and we identify several important factors that cause noise and coupling to synchronize or desynchronize a system. By introducing noise in various ways, we find an estimate for the onset of synchrony of a system in terms of the coupling strength, noise strength, and width of the frequency distribution of its natural oscillations. We also demonstrate that noise alone can be sufficient to synchronize nonidentical oscillators. However, this synchrony depends on the first Fourier mode of a phase-sensitivity function, through which we introduce common noise into the system. We show that higher Fourier modes can cause desynchronization due to clustering effects, and that this can reinforce clustering caused by different forms of coupling. Finally, we discuss the effects of noise on an ensemble in which antiferromagnetic coupling causes oscillators to form two clusters in the absence of noise. © 2013 American Physical Society.

  11. Feasibility of Johnson Noise Thermometry based on Digital Signal Processing Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, In Koo [KAERI, Daejeon (Korea, Republic of); Kim, Yang Mo [Chungnam National University, Daejeon (Korea, Republic of)

    2014-08-15

    This paper presents an implementation strategy of noise thermometry based on a digital signal processing technique and demonstrates its feasibilities. A key factor in its development is how to extract the small thermal noise signal from other noises, for example, random noise from amplifiers and continuous electromagnetic interference from the environment. The proposed system consists of two identical amplifiers and uses a cross correlation function to cancel the random noise of the amplifiers. Then, the external interference noises are eliminated by discriminating the difference in the peaks between the thermal signal and external noise. The gain of the amplifiers is estimated by injecting an already known pilot signal. The experimental simulation results of signal processing methods have demonstrated that the proposed approach is an effective method in eliminating an external noise signal and performing gain correction for development of the thermometry.

  12. Studying the Noise Control Engineering Protocols in Industry

    Directory of Open Access Journals (Sweden)

    Hamid Golshah

    1999-03-01

    Full Text Available Today, sound is one of the detrimental factors in the workplace and its harmful impact has been so important that scientists have named it “Noise Pollutions”. Hearing is one of the five senses of human being which is also a medium for communicating with other s and enjoying the pleasant feeling of listening to a piece of music. In spite of this, changes in the intensity and frequency of sound can make it annoying. Using Sound Level Meter to measure the dB of noise in the workplace and noise control principles will be discussed here.

  13. Quantum Noise Locking

    CERN Document Server

    McKenzie, K; Goda, K; Lam, P K; Grosse, N; Gray, M B; Mavalvala, N; McClelland, D E; Kenzie, Kirk Mc; Mikhailov, Eugeniy; Goda, Keisuke; Lam, Ping Koy; Grosse, Nicolai; Gray, Malcolm B.; Mavalvala, Nergis; Clelland, David E. Mc

    2005-01-01

    Quantum optical states which have no coherent amplitude, such as squeezed vacuum states, can not rely on standard readout techniques to generate error signals for control of the quadrature phase. Here we investigate the use of asymmetry in the quadrature variances to obtain a phase-sensitive readout and to lock the phase of a squeezed vacuum state, a technique which we call noise locking (NL). We carry out a theoretical derivation of the NL error signal and the associated stability of the squeezed and anti-squeezed lock points. Experimental data for the NL technique both in the presence and absence of coherent fields are shown, including a comparison with coherent locking techniques. Finally, we use NL to enable a stable readout of the squeezed vacuum state on a homodyne detector.

  14. Quantum noise locking

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, Kirk [Center for Gravitational Physics, Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Mikhailov, Eugeniy E [LIGO Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Goda, Keisuke [LIGO Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Lam, Ping Koy [Quantum Optics Group, Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Grosse, Nicolai [Quantum Optics Group, Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Gray, Malcolm B [Center for Gravitational Physics, Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Mavalvala, Nergis [LIGO Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); McClelland, David E [Center for Gravitational Physics, Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia)

    2005-10-01

    Quantum optical states which have no coherent amplitude, such as squeezed vacuum states, cannot rely on standard readout techniques to generate error signals for control of the quadrature phase. Here we investigate the use of asymmetry in the quadrature variances to obtain a phase-sensitive readout and to lock the phase of a squeezed vacuum state, a technique which we call noise locking (NL). We carry out a theoretical derivation of the NL error signal and the associated stability of the squeezed and anti-squeezed lock points. Experimental data for the NL technique both in the presence and absence of coherent fields are shown, including a comparison with coherent locking techniques. Finally, we use NL to enable a stable readout of the squeezed vacuum state on a homodyne detector.

  15. THE AIRPORT NOISE PREDICTION METHOD AND THE INFLUENCING FACTORS BA SE D ONI NM (IN TEGRATED NOI SE MODEL)%基于综合噪声模型 INM 的机场噪声预测方法及其影响因素研究

    Institute of Scientific and Technical Information of China (English)

    李冉

    2013-01-01

    The aircraft noise pollution has come a serious environmental problem as the development of civil aviation , the improvement of airport construction and the growth of airport projects .Currently , the most effective ways of solving the airport noise pollution are to protect the sensitive areas around airport and optimize the land use according the prediction and assessment of airport noise .Therefore, the accuracy of airport noise assessment is very important .In this paper , we introduced the status of airport noise assessment in China and the assessment criteria and described the airport noise assessment method .Meanwhile , we used INM ( Integrated Noise Model ) which was developed by FAA ( Federal Aviation Administration ) to analyse various influence factors .These factors include aircraft fleet , runway use、flight time、ter-rain condition、flight rocedure .They will decide the levels and range of the airport noise .Therefore, this paper contributed the further devel-opment of airport noise predicting technic and method .%随着我国航空运输业的不断发展,全国机场布局规划的不断完善,机场建设项目近年不断增多,飞机噪声污染已经成为各城市日益严重的环境问题,目前,通过机场噪声的预测和评价,根据预测结果对机场周边敏感保护目标采取措施,改变和优化机场周边土地利用规划,是解决机场噪声问题的最有效方式,因此确保机场噪声预测准确性显得尤为重要。本文主要对我国机场噪声评价现状和评价指标进行了介绍,重点对机场噪声影响评价技术方法进行了论述,结合FAA(美国联邦航空局)开发的机场噪声模型INM(综合噪声模型)对影响机场噪声预测的各种因素进行了详细分析,分别研究了机型组合、起降方向、航班时刻安排、地形条件、飞行程序等多种因素对机场噪声程度和分布范围的影响分析,为机场噪声预测技术

  16. Shot noise of the spin inelastic tunneling through a quantum dot with single molecule-magnet

    Institute of Scientific and Technical Information of China (English)

    Chang Bo; Liang Jiu-Qing

    2011-01-01

    We have studied the quantum fluctuations of inelastic spin-electron scattering in quantum dot with an embedded biaxial single molecule-magnet and particularly investigated the zero-frequency shot noise and Fano factor in different magnetic fields. It is found that the shot noise and Fano factor exhibit a stepwise behaviour as bias increases in the presence of interaction between the electron and molecule-magnet for a weak magnetic field. As magnetic field becomes strong, a dip is displayed in the shot-noise-bias curve due to the suppression of inelastic shot noise caused by the quantum tunneling of magnetisation. Because of the spontaneous inelastic tunneling at zero bias, a small shot noise occurs, which results in the case of Fano factor F > 1. Moreover, our results show that the sweeping speed can also influence the shot noise and Fano factor obviously.

  17. DUPIC fuel compatibility assessment

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hang Bok; Rho, G. H.; Park, J. W. [and others

    2000-03-01

    The purpose of this study is to assess the compatibility of DUPIC(Direct Use of Spent PWR Fuel in CANDU Reactors) fuel with the current CANDU 6 reactor, which is one of the technology being developed to utilize the spent PWR fuel in CANDU reactors. The phase 1 study of this project includes the feasibility analysis on applicability of the current core design method, the feasibility analysis on operation of the DUPIC fuel core, the compatibility analysis on individual reactor system, the sensitivity analysis on the fuel composition, and the economic analysis on DUPIC fuel cycle. The results of the validation calculations have confirmed that the current core analysis system is acceptable for the feasibility study of the DUPIC fuel compatibility analysis. The results of core simulations have shown that both natural uranium and DUPIC fuel cores are almost the same from the viewpoint of the operational performance. For individual reactor system including reactively devices, the functional requirements of each system are satisfied in general. However, because of the pronounced power flattening in the DUPIC core, the radiation damage on the critical components increases, which should be investigated more in the future. The DUPIC fuel composition heterogeneity dose not to impose any serious effect on the reactor operation if the fuel composition is adjusted. The economics analysis has been performed through conceptual design studies on the DUPIC fuel fabrication, fuel handling in a plant, and spent fuel disposal, which has shown that the DUPIC fuel cycle is comparable to the once-trough fuel cycle considering uncertainties associated with unit costs of the fuel cycle components. The results of Phase 1 study have shown that it is feasible to use the DUPIC fuel in CANDU reactors without major changes in hardware. However further studies are required to confirm the safety of the reactor under accident condition.

  18. The West London Schools Study: the effects of chronic aircraft noise exposure on child health.

    Science.gov (United States)

    Haines, M M; Stansfeld, S A; Brentnall, S; Head, J; Berry, B; Jiggins, M; Hygge, S

    2001-11-01

    Previous field studies have indicated that children's cognitive performance is impaired by chronic aircraft noise exposure. However, these studies have not been of sufficient size to account adequately for the role of confounding factors. The objective of this study was to test whether cognitive impairments and stress responses (catecholamines, cortisol and perceived stress) are attributable to aircraft noise exposure after adjustment for school and individual level confounding factors and to examine whether children exposed to high levels of social disadvantage are at greater risk of noise effects. The cognitive performance and health of 451 children aged 8-11 years, attending 10 schools in high aircraft noise areas (16 h outdoor Leq > 63 dBA) was compared with children attending 10 matched control schools exposed to lower levels of aircraft noise (16 h outdoor Leq < 57 dBA). Noise exposure was associated with impaired reading on difficult items and raised annoyance, after adjustment for age, main language spoken and household deprivation. There was no variation in the size of the noise effects in vulnerable subgroups of children. High levels of noise exposure were not associated with impairments in mean reading score, memory and attention or stress responses. Aircraft noise was weakly associated with hyperactivity and psychological morbidity. Chronic noise exposure is associated with raised noise annoyance in children. The cognitive results indicate that chronic aircraft noise exposure does not always lead to generalized cognitive effects but, rather, more selective cognitive impairments on difficult cognitive tests in children.

  19. Thermodynamic analysis of biofuels as fuels for high temperature fuel cells

    Science.gov (United States)

    Milewski, Jarosław; Bujalski, Wojciech; Lewandowski, Janusz

    2013-02-01

    Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC) are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV) for projects was estimated and commented.

  20. Thermodynamic analysis of biofuels as fuels for high temperature fuel cells

    Directory of Open Access Journals (Sweden)

    Milewski Jarosław

    2013-02-01

    Full Text Available Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC and molten carbonate fuel cell (MCFC have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV for projects was estimated and commented.

  1. Active Noise Control of Radiated Noise from Jets Originating NASA

    Science.gov (United States)

    Doty, Michael J.; Fuller, Christopher R.; Schiller, Noah H.; Turner, Travis L.

    2013-01-01

    The reduction of jet noise using a closed-loop active noise control system with highbandwidth active chevrons was investigated. The high frequency energy introduced by piezoelectrically-driven chevrons was demonstrated to achieve a broadband reduction of jet noise, presumably due to the suppression of large-scale turbulence. For a nozzle with one active chevron, benefits of up to 0.8 dB overall sound pressure level (OASPL) were observed compared to a static chevron nozzle near the maximum noise emission angle, and benefits of up to 1.9 dB OASPL were observed compared to a baseline nozzle with no chevrons. The closed-loop actuation system was able to effectively reduce noise at select frequencies by 1-3 dB. However, integrated OASPL did not indicate further reduction beyond the open-loop benefits, most likely due to the preliminary controller design, which was focused on narrowband performance.

  2. Energy-based wavelet de-noising of hydrologic time series.

    Science.gov (United States)

    Sang, Yan-Fang; Liu, Changming; Wang, Zhonggen; Wen, Jun; Shang, Lunyu

    2014-01-01

    De-noising is a substantial issue in hydrologic time series analysis, but it is a difficult task due to the defect of methods. In this paper an energy-based wavelet de-noising method was proposed. It is to remove noise by comparing energy distribution of series with the background energy distribution, which is established from Monte-Carlo test. Differing from wavelet threshold de-noising (WTD) method with the basis of wavelet coefficient thresholding, the proposed method is based on energy distribution of series. It can distinguish noise from deterministic components in series, and uncertainty of de-noising result can be quantitatively estimated using proper confidence interval, but WTD method cannot do this. Analysis of both synthetic and observed series verified the comparable power of the proposed method and WTD, but de-noising process by the former is more easily operable. The results also indicate the influences of three key factors (wavelet choice, decomposition level choice and noise content) on wavelet de-noising. Wavelet should be carefully chosen when using the proposed method. The suitable decomposition level for wavelet de-noising should correspond to series' deterministic sub-signal which has the smallest temporal scale. If too much noise is included in a series, accurate de-noising result cannot be obtained by the proposed method or WTD, but the series would show pure random but not autocorrelation characters, so de-noising is no longer needed.

  3. Common mode noise modeling and its suppression in ultra-high efficiency full bridge boost converter

    DEFF Research Database (Denmark)

    Makda, Ishtiyaq Ahmed; Nymand, Morten; Madawala, Udaya

    2013-01-01

    In this paper, common mode noise modeling of low-voltage high-current isolated full bridge boost dc-dc converters intended for fuel cell application is presented. Due to the tightly coupled primary and secondary windings of the transformer, such converter has inherently large capacitive coupling...... between input and output which is normally associated with high common mode noise generation. In this work, common mode noise sources in the converter are identified, and a common mode noise model is developed. Based on the established noise model, a practical CM filter is designed to comply...... with the CISPR-A requirements. Finally, a 3kW dc-dc converter including filters has been built and tested to verify the theoretical model. Experimental results confirm the theoretical analysis of the converter....

  4. A review and tutorial discussion of noise and signal-to-noise ratios in analytical spectrometry—III. Multiplicative noises

    NARCIS (Netherlands)

    Alkemade, C.T.J.; Snelleman, W.; Boutilier, G.D.; Winefordner, J.D.

    1980-01-01

    In this review, signal-to-noise ratios are discussed in a tutorial fashion for the case of multiplicative noise. Multiplicative noise is introduced simultaneously with the analyte signal and is therefore much more difficult to reduce than additive noise. The sources of noise, the mathematical repres

  5. Selection of Fuel by Using Analytical Hierarchy Process

    Directory of Open Access Journals (Sweden)

    Asilata M. Damle,

    2015-04-01

    Full Text Available Selection of fuel is a very important and critical decision one has to make. Various criteria are to be considered while selecting a fuel. Some of important criteria are Fuel Economy, Availability of fuel, Pollution from vehicle, Maintenance of the vehicle. Selection of best fuel is a complex situation. It needs a multi-criteria analysis. Earlier, the solution to the problem were found by applying classical numerical methods which took into account only technical and economic merits of the various alternatives. By applying multi-criteria tools, it is possible to obtain more realistic results. This paper gives a systematic analysis for selection of fuel by using Analytical Hierarchy Process (AHP. This is a multi-criteria decision making process. By using AHP we can select the fuel by comparing various factors in a mathematical model. This is a scientific method to find out the best fuel by making pairwise comparisons.

  6. Survey of nuclear fuel cycle economics: 1970--1985

    Energy Technology Data Exchange (ETDEWEB)

    Prince, B. E.; Peerenboom, J. P.; Delene, J. G.

    1977-03-01

    This report is intended to provide a coherent view of the diversity of factors that may affect nuclear fuel cycle economics through about 1985. The nuclear fuel cycle was surveyed as to past trends, current problems, and future considerations. Unit costs were projected for each step in the fuel cycle. Nuclear fuel accounting procedures were reviewed; methods of calculating fuel costs were examined; and application was made to Light Water Reactors (LWR) over the next decade. A method conforming to Federal Power Commission accounting procedures and used by utilities to account for backend fuel-cycle costs was described which assigns a zero net salvage value to discharged fuel. LWR fuel cycle costs of from 4 to 6 mills/kWhr (1976 dollars) were estimated for 1985. These are expected to reach 6 to 9 mills/kWr if the effect of inflation is included.

  7. Spin-flip noise in a multiterminal spin valve

    OpenAIRE

    Belzig, Wolfgang; Zareyan, Malek

    2004-01-01

    We study shot noise and cross-correlations in a four terminal spin-valve geometry using a Boltzmann-Langevin approach. The Fano factor (shot noise to current ratio) depends on the magnetic configuration of the leads and the spin-flip processes in the normal metal. In a four-terminal geometry, spin-flip processes are particularly prominent in the cross-correlations between terminals with opposite magnetization.

  8. Study on Noise Acceptance and Personality Factors of University Students in Library%高校学生在图书馆中的噪音接受能力与个性因素研究

    Institute of Scientific and Technical Information of China (English)

    肖红

    2015-01-01

    针对图书馆噪音问题,介绍美国南阿拉巴马大学进行背景噪音分组实验来研究人对声音环境的需求本质,并对结果进行分析。重点分析实验结果对我国图书馆的影响和引发的思考。%The paper aims at the issue of library noise, introduces background noise grouping experiment to study the nature of human need for sound environment in University of South Alabama in United States, and analyzes the results. The paper focuses on in-fluences and enlightenments of the research results on China’s library.

  9. [Influence of environmental noise on sleep quality and sleeping disorders-implications for health].

    Science.gov (United States)

    Kohlhuber, M; Bolte, G

    2011-12-01

    Environmental noise is a well-known risk factor influencing sleep-wake behavior and sleep quality. Epidemiologic studies have shown that environmental noise is regarded as the most annoying environmental factor. Noise causes modifications in physiologic and mental functions and may result in health outcomes like elevated blood pressure and ischemic heart disease. Reactions to high sound levels during sleep are decreased sleep intensity, arousals, and increased stress hormone secretion. Effects of poor sleep quality are reduced cognitive performance, tiredness, and psychosomatic symptoms. Long-term consequences of recurrent sleep loss due to environmental noise may be heart disease and increased medication intake. Arousals occur especially due to single noise events and intermittent noise. Laboratory and field studies showed no habituation of physiologic parameters to high sound levels. Sleep is especially sensitive to noise; therefore, sound levels during nighttime should be much lower than during daytime.

  10. Cf-source-driven neutron-noise measurements of subcriticality for a 4. 95 wt% /sup 235/U-enriched uranyl fluoride solution cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Mihalczo, J.T.; Kryter, R.T.; King, W.T.; Blakeman, E.D.

    1986-01-01

    A method for determining the reactivity of subcritical systems of fissile material, using neutron-noise power spectral density measurements in conjunction with a /sup 252/Cf source, has been tested in experiments with an aqueous solution containing uranium fluoride (4.95 wt% /sup 235/U). The kappasub(eff)-values obtained from the ratio of spectral densities G*/sub 12/G/sub 13//G/sub 11/G/sub 23/ agreed with those from break-frequency noise analysis and with bias-corrected transport theory calculations within the statistical uncertainty of the measurements. Corrections for the effects of spatial modes and source-detector locations appear to be well-understood, since measurements for a variety of source-detector positions resulted in essentially the same kappasub(eff)-values. Modal correction factors were such that ignoring them would result in higher values of kappasub(eff) than actually occur. The measurements have demonstrated the applicability of the /sup 252/Cf-source-driven neutron-noise analysis method to the measurement of the subcritical neutron multiplication factor for a fuel solution system.

  11. The analysis on the restricting factors and countermeasures of airport noise pollution control%机场噪声污染防治制约因素与对策

    Institute of Scientific and Technical Information of China (English)

    吴娜伟; 王亚男; 李冉; 虞朝晖; 孙琪

    2014-01-01

    With the rapid development of air transport industry, the airport noise problemhas become increasingly prominent.The construction and development of airports wereobstructed byseveral issues, such as imperfect airport noise control standards, unreasonable airport site selection, and unfulfillment of deceasing-noise measuresimplementation. As an important pre management means to control the environmental risks of the airport construction project, environmental impact assessment not only has great influence on controlling the negative effects of airport noise, but also benefit to achieve the connection between the selection and construction of the airport and the local city planning. And this will avoid the old development pattern of“the airport being surrounded by city”, then to achieve the coordinated development of the airport and the city.%随着我国航空运输业的迅速发展,机场噪声问题日益突出。飞机噪声控制标准不完善、机场选址不合理、降噪措施落实不到位等问题,不利于机场的建设和发展。环境影响评价作为控制机场建设项目环境风险重要的前置性的管理手段,对控制机场噪声的不良环境影响具有重要作用,也有利于实现机场选址和建设与当地有关的规划衔接,避免走“城市包围机场”的老路,有利于实现到机场和城市发展的协调。

  12. Relationship between noise and job stress at a private thread spinning company

    Directory of Open Access Journals (Sweden)

    Andi Mursali

    2009-04-01

    Full Text Available Noise exposure is one of the major occupational hazards in many places, and has several health effects, including hearing loss and psychological effects such as sleep disturbances and mental stress. The objective of this research was to determine the relationship between noise and stress and other risk factors that affect job stress. A cross-sectional comparative design involved a total of 326 workers consisting of 220 workers in high noise conditions and 106 workers in low noise conditions. The data were collected directly from the respondents by filling out the questionnaire on worker characteristics, the stress diagnostic questionnaire, and the symptom checklist 90, through discussions with company management, and by measurement of noise levels. The job stress prevalence in workers in high noise conditions was 55% and in those in low noise conditions 24.5%. The results showed that risk factors such as gender of workers, noise conditions, habitual use of ear plugs, shift work, and work stressors had a significant relationship with job stress. Multivariate analysis indicated that the habit of using earplugs was a dominant risk factor causing job stress. The prevalence of job stress in high noise conditions was higher than that in workers in low noise conditions. Noise conditions have a significant relationship with job stress (OR=2.46; 95% CI 1.33 - 4.55. Workers in high noise conditions who did not always use or never had used ear plugs had a higher chance of experiencing stress than those in low noise conditions who did not need ear plugs (OR=21.76; 95% CI 8.09 - 58.52. This study supported that noise exerts its health effect via stress, since noise often raise stress in various ways.

  13. Relationship between noise and job stress at a private thread spinning company

    Directory of Open Access Journals (Sweden)

    Andi Mursali

    2016-02-01

    Full Text Available Noise exposure is one of the major occupational hazards in many places, and has several health effects, including hearing loss and psychological effects such as sleep disturbances and mental stress. The objective of this research was to determine the relationship between noise and stress and other risk factors that affect job stress. A cross-sectional comparative design involved a total of 326 workers consisting of 220 workers in high noise conditions and 106 workers in low noise conditions. The data were collected directly from the respondents by filling out the questionnaire on worker characteristics, the stress diagnostic questionnaire, and the symptom checklist 90, through discussions with company management, and by measurement of noise levels. The job stress prevalence in workers in high noise conditions was 55% and in those in low noise conditions 24.5%. The results showed that risk factors such as gender of workers, noise conditions, habitual use of ear plugs, shift work, and work stressors had a significant relationship with job stress. Multivariate analysis indicated that the habit of using earplugs was a dominant risk factor causing job stress. The prevalence of job stress in high noise conditions was higher than that in workers in low noise conditions. Noise conditions have a significant relationship with job stress (OR=2.46; 95% CI 1.33 - 4.55. Workers in high noise conditions who did not always use or never had used ear plugs had a higher chance of experiencing stress than those in low noise conditions who did not need ear plugs (OR=21.76; 95% CI 8.09 - 58.52. This study supported that noise exerts its health effect via stress, since noise often raise stress in various ways.

  14. Phase noise in RF and microwave amplifiers.

    Science.gov (United States)

    Boudot, Rodolphe; Rubiola, Enrico

    2012-12-01

    Understanding amplifier phase noise is a critical issue in many fields of engineering and physics, such as oscillators, frequency synthesis, telecommunication, radar, and spectroscopy; in the emerging domain of microwave photonics; and in exotic fields, such as radio astronomy, particle accelerators, etc. Focusing on the two main types of base noise in amplifiers, white and flicker, the power spectral density of the random phase φ(t) is Sφ(f) = b(0) + b(-1)/f. White phase noise results from adding white noise to the RF spectrum in the carrier region. For a given RF noise level, b(0) is proportional to the reciprocal of the carrier power P(0). By contrast, flicker results from a near-dc 1/f noise-present in all electronic devices-which modulates the carrier through some parametric effect in the semiconductor. Thus, b(-1) is a parameter of the amplifier, constant in a wide range of P(0). The consequences are the following: Connecting m equal amplifiers in parallel, b(-1) is 1/m times that of one device. Cascading m equal amplifiers, b(-1) is m times that of one amplifier. Recirculating the signal in an amplifier so that the gain increases by a power of m (a factor of m in decibels) as a result of positive feedback (regeneration), we find that b(-1) is m(2) times that of the amplifier alone. The feedforward amplifier exhibits extremely low b(-1) because the carrier is ideally nulled at the input of its internal error amplifier. Starting with an extensive review of the literature, this article introduces a system-oriented model which describes the phase flickering. Several amplifier architectures (cascaded, parallel, etc.) are analyzed systematically, deriving the phase noise from the general model. There follow numerous measurements of amplifiers using different technologies, including some old samples, and in a wide frequency range (HF to microwaves), which validate the theory. In turn, theory and results provide design guidelines and give suggestions for CAD and

  15. Risk behaviour and noise exposure among adolescents.

    Science.gov (United States)

    Bohlin, Margareta C; Erlandsson, Soly I

    2007-01-01

    Adolescents in Western society often expose themselves to high levels of sound in gyms, rock concerts, discotheques etc. As these behaviours are as threatening to young people's health as more traditional risk behaviours are, our aim in the present study was to analyze the relationship between self-exposure to noise, risk behaviours and risk judgements among 310 Swedish adolescents aged 15-20 (167 men; 143 women). Adolescents' behaviour in different traditional risk situations correlated with behaviour in noisy environments, while judgements about traditional risks correlated with judgements regarding noise exposure. It is an interesting finding that although young women judge risk situations as generally more dangerous than young men do, they nevertheless behave in the same way. We suggest that this difference is a social and cultural phenomenon which underscores the importance of adopting a gender perspective in the analysis of risk factors. Adolescents reporting permanent tinnitus judged loud music as more risky than adolescents with no symptoms and they did not listen to loud music as often as those with occasional tinnitus. Research on hearing prevention for young people needs to acknowledge and make use of theories on risk behaviour, especially due to the existence of a relationship between adolescents' risk-taking in noisy environments and other types of risk-taking. Similarly, theories on risk behaviour should acknowledge noise as a risk factor.

  16. Fast High-Quality Noise

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Wyvill, Geoff

    2007-01-01

    At the moment the noise functions available in a graphics programmer's toolbox are either slow to compute or they involve grid-line artifacts making them of lower quality. In this paper we present a real-time noise computation with no grid-line artifacts or other regularity problems. In other wor...

  17. Consumer oriented product noise testing

    Science.gov (United States)

    Blomberg, Les

    2005-09-01

    This paper explores the need for product noise measurements and how best to meet that need in the near future. Currently there is only a small market place for quieter consumer products. This is not because of lack of interest. No one really wants to announce to everyone in their house that they just flushed the toilet, few really want the entire neighborhood to know they are mowing their yard, etc. The small market place is primarily due to a lack of regulations on product noise, a lack of information easily available to consumers about which products are quieter, and market consolidation resulting in fewer manufacturers, most of whom are unwilling to emphasize their quieter products at the risk of eroding sales of their noisier ones (that currently have greater market share). In the absence of the EPA fulfilling its statutory requirement to regulate and label product noise under the Noise Control Act of 1972, and with the unwillingness of most industries to voluntarily publish accurate product noise data, there is a significant role for ``Consumer Oriented Product Noise Testing.'' This paper explores the Noise Pollution Clearinghouse's ongoing and planned product noise testing, evaluating its advantages, disadvantages, and limitations.

  18. Noise and health of children

    NARCIS (Netherlands)

    Passchier, W.

    2000-01-01

    The world of the child is becoming noisier and noisier. Compared to the mid-fifties environ-mental noise levels (sources such as road traffic, aircraft) increased substantially, causing higher noise levels during day- and night-time at home, at school and during out- and indoors leisure time activit

  19. Generation of spatiotemporal colored noise

    OpenAIRE

    García Ojalvo, Jordi; Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria

    1992-01-01

    We develop an algorithm to simulate a Gaussian stochastic process that is non-δ-correlated in both space and time coordinates. The colored noise obeys a linear reaction-diffusion Langevin equation with Gaussian white noise. This equation is exactly simulated in a discrete Fourier space. Peer Reviewed

  20. Divide and conquer spot noise

    NARCIS (Netherlands)

    Leeuw, W.C. de; Liere, R. van

    1997-01-01

    The design and implementation of an interactive spot noise algorithm is presented. Spot noise is a technique which utilizes texture for the visualization of flow fields. Various design tradeoffs are discussed that allow an optimal implementation on a range of high end graphical workstations. Two app