Transient Emissions Research Articles

Neuro-fuzzy model tree approach to virtual sensing of transient diesel soot and NOx emissions

Diesel engine combustion and emission formation are highly nonlinear and thus create a challenge related to engine diagnostics and engine control with emission feedback. This article describes the development of neuro-fuzzy models for prediction of transient NOX and soot emission from a diesel engine. The modeling techniques are motivated by the idea of divide and conquer the input–output space. The complex problem is divided into multiple simpler subproblems, which are then identified using simpler class of models. This article explores two different choices of local models, specifically polynomial and neural networks. The modeling technique is augmented with input relevance algorithm to select the most relevant input regressors. Two algorithms, namely, orthogonal least square and automatic relevance determination, are introduced. The models are data driven, and an advanced experimental setup incorporating a medium duty diesel engine and fast emission analyzers for soot and NOX is used to generate training data. The choice of local models and input relevance algorithm is validated with instantaneous emission recorded during transient schedules different from those used in development. High prediction accuracy, both qualitatively and quantitatively, is demonstrated with low computational cost.

Cochlear condition and olivocochlear system of gas station attendants exposed to organic solvents

Introduction: Organic solvents have been increasingly studied due to its ototoxic action. Objective: Evaluate the conditions of outer hair cells and olivocochlear system in individuals exposed to organic solvents. Method: This is a prospective study. 78 gas station attendants exposed to organic solvents had been evaluated from three gas stations from Santa Maria city, Rio Grande do Sul (RS). After applying the inclusion criteria, the sample was constituted by 24 individuals. The procedures used on the evaluation were audiological anamnesis, Transient otoacoustic emissions (TEOAES) and research for the suppressive effect of TEOAES. A group control (GC) compounded by 23 individuals was compared to individuals exposed and non-exposed individuals. The data collection has been done in the room of Speech Therapy of Workers Health Reference Center of Santa Maria. Results: The TEOAES presence was major in the left ear in both groups; the average relation of TEOAES signal/noise in both ears was greater in GE; the TEOAES suppressive effect in the right ear was higher in the individual of GE (62,5%) and in the left ear was superior in GC (86,96%), with statistically significant difference. The median sign/noise ratio of TEOAES, according to the frequency range, it was higher in GC in three frequencies ranges in the right ear and one in the left ear. Conclusion: It was not found signs of alteration on the outer hair cells neither on the olivocochlear medial system in the individuals exposed to organic solvents.

Optimal energy management for a diesel hybrid electric vehicle considering transient PM and quasi-static NOx emissions

In this paper, optimal energy management strategies are derived to balance fuel consumption, raw particulate matter (PM) emissions, and raw nitrogen oxide (NOx) emissions for a Diesel hybrid electric vehicle. Two methods for the derivation of these strategies are compared. One method is based on dynamic programming and steady-state engine maps only. The second method is based on dynamic programming, steady-state engine maps, and a validated transient PM emission model. As a result, only the second method allows for the generation of smooth engine set point trajectories to reduce transient PM emissions without compromising fuel consumption and NOx emissions.

Alterations in cochlear function after exposure to short term broad band noise assessed by otoacoustic emissions.

Sudden or chronic exposure to sound alters the functioning of cochlea. This results in temporary or permanent alteration of functioning of cochlear cells. Alteration of functioning of outer hair cells (OHC) of cochlea following exposure to noise can be assessed by measurement of transient otoacoustic emissions (TEOAE). Such a measurement is of great clinical importance in early detection of the damage to the OHC. In this study we aim to study effect of noise on outer hair cell function by studying the changes in TEOAE's amplitude following exposure to short term broad band noise in healthy volunteers. Twenty volunteers' ten males and ten females participated in the study. They underwent pure tone and impedance audiometry to rule out ear pathology. Then pre-exposure TEOAE's were recorded. After that they were exposed to broad band noise for two minutes. After gap of five minutes again TEOAE's were recorded. Pre and post exposure amplitude of TEOAE's was analysed statistically.s There was statistically significant difference between pre exposure and post-exposure amplitude of TEOAE's. Pre and post exposure values for A & B amplitudes showed p-value of 0.0001 whereas values for A-B amplitude showed p-value of 0.0001. Measurement of TEOAE's can detect early changes in the functioning of outer hair cells which cannot be picked by routine pure tone audiometry. Thus they can be used in assessing early changes in cochlear function following exposure to noise in individuals exposed to sudden noise or working in noisy environments. Thus preventive methods to reduce the noise induced hearing loss in such individuals can be implemented.

Auditory brainstem response in neonates: influence of gender and weight/gestational age ratio.

OBJECTIVE: To investigate the influence of gender and weight/gestational age ratio on the Auditory Brainstem Response (ABR) in preterm (PT) and term (T) newborns. METHODS: 176 newborns were evaluated by ABR; 88 were preterm infants - 44 females (22 small and 22 appropriate for gestational age) and 44 males (22 small and 22 appropriate for gestational age). The preterm infants were compared to 88 term infants - 44 females (22 small and 22 appropriate for gestational age) and 44 males (22 small and 22 appropriate for gestational age). All newborns had bilateral presence of transient otoacoustic emissions and type A tympanometry. RESULTS: No interaural differences were found. ABR response did not differentiate newborns regarding weight/gestational age in males and females. Term newborn females showed statistically shorter absolute latencies (except on wave I) than males. This finding did not occur in preterm infants, who had longer latencies than term newborns, regardless of gender. CONCLUSIONS: Gender and gestational age influence term infants' ABR, with lower responses in females. The weight/gestational age ratio did not influence ABR response in either groups.

Amplitude das emissões otoacústicas produto de distorção e o uso de contraceptivos hormonais: estudo preliminar

OBJETIVO: Identificar se há diferença na amplitude das emissões otoacústicas de mulheres que utilizam e que não utilizam contraceptivo hormonal. MÉTODOS: Participaram da pesquisa 30 mulheres, sendo 15 que utilizam o método contraceptivo hormonal e 15 que não o utilizam, todos sem queixa auditiva e com audição dentro dos padrões de normalidade. A coleta de dados foi realizada por meio das emissões otoacústicas transientes e pelas emissões otoacústicas produto de distorção. RESULTADOS: Não houve diferença entre os valores de amplitude das emissões otoacústicas produto de distorção para as frequências de 1 kHz, 1,4 kHz, 2,8 kHz, 4 kHz e 6 kHz, na orelha direita, nos grupos estudados. Na frequência de 2 kHz houve tendência à diferença entre os valores de amplitude das emissões otoacústicas produto de distorção, comparando-se o grupo de mulheres que não usam contraceptivo hormonal e o grupo das que usam. Na orelha esquerda, não houve diferença entre os valores de amplitude das emissões otoacústicas produto de distorção para as frequências de 1 kHz, 1,4 kHz, 2 kHz, 2,8 kHz, 4 kHz e 6 kHz, nos dois grupos analisados. CONCLUSÃO: Não foram observadas diferenças na amplitude das emissões otoacústicas produto de distorção pelo uso de contraceptivo hormonal, nos grupos estudados.

Space-Frequency Analysis and Experimental Measurement of Magnetic Field Emissions Radiated by High-Speed Railway Systems

This paper shows that in the radiated emission spectrum of high-speed railway systems, a low-frequency range exists in which the magnetic field space-frequency distribution is determined, to a large extent, by the railway infrastructure features. To prove this, electromagnetic modeling of a suitably long stretch of the railway infrastructure is developed, and an ad hoc experimental campaign is carried out for comparison. Modeling and experimental measurements refer to a 50 km stretch of the Italian 2 × 25 kV ac railway system. Infrastructure simulation is obtained by resorting to a simplified approach based on multiconductor transmission line. To this end, short segments of uniform lines are cascade-connected with lumped networks representing equipment and electrical devices placed along the line, and the radiated magnetic field is evaluated from the corresponding noise-current distributions. Since the emission source, i.e., the train, has unknown electrical properties, it is represented as a unit-current source. Thus, the proposed model provides a transfer ratio between the radiated magnetic field and the current source. As a result, the maximum values of train current corresponding to magnetic field limits provided by the International Standards can be readily derived. An optimized measurement procedure is used to show that in the frequency band 60-120 kHz, transient emissions due to random and unpredictable phenomena are negligible. In such a frequency range, where continuous and persistent emissions are present, the structure of time-frequency measurement data is readily explained, and the role of the railway infrastructure on the radiated magnetic field is unambiguously identified.

Alterações auditivas associadas a complicações e comorbidades no diabetes mellitus tipo 2

OBJETIVO: Investigar a presença de alterações auditivas, representadas por diminuição do limiar audiométrico e/ou ausência de emissões otoacústicas, associadas às características gerais, complicações crônicas e comorbidades em pacientes com diabetes tipo 2. MÉTODOS: Estudo realizado em unidade de atenção secundária, em Fortaleza, de abril a julho de 2010. Amostra de 152 pacientes de 36 a 60 anos de idade, portadores de diabetes tipo 2. Analisou-se dados clínicos relacionados ao diabetes e à avaliação audiológica, composta por audiometria tonal liminar, emissões otoacústicas evocadas por estímulo transiente e emissões otoacústicas evocadas produto de distorção. RESULTADOS: O gênero feminino predominou, com 95 (62,5%) pacientes. A média de idade foi 53,4 anos. Verificou-se perda auditiva sensorioneural em 96 (63,2%) pacientes, sendo a maioria perda coclear (83,3%). Cento e catorze pacientes (75%) apresentaram ausência de emissões transientes e 120 (78,9%), ausência de emissões produto de distorção. Os homens diabéticos demonstraram 4,4 vezes mais chance de perda auditiva que as mulheres. Quanto maior o tempo da doença, maior a probabilidade de perda auditiva. Os pacientes diabéticos acima de 50 anos também apresentaram maior chance para perda auditiva. CONCLUSÃO: Das comorbidades e complicações associadas ao diabetes, o sobrepeso/obesidade constitui fator de risco para alteração auditiva, estando associado à perda auditiva e ausência de emissões transientes. Os pacientes diabéticos com sobrepeso/obesidade apresentaram três vezes mais chances de alterações na audiometria e emissões otoacústicas.

Optimal control of the transient emissions and the fuel efficiency of a diesel hybrid electric vehicle

As an important technical innovation which has emerged in the automotive industry, powertrain hybridization has been considered as one of the most effective ways for addressing transportation energy consumption and environmental concerns. However, owing to the complex physical and chemical nature of the engine combustion process, and the dynamic interactions between the engine and the alternative power source, it is difficult to optimize simultaneously and precisely both the engine fuel consumption and the emissions, especially during transient operations. Targeted at achieving both global energy optimization and reduction in the transient emissions, a control-oriented diesel engine emission model is first investigated and identified using a large number of experimental data. On this basis, a two-mode hybrid energy management strategy is proposed. In the ‘fuel-efficiency-improving’ mode, a dynamic programming algorithm is used to seek global optimization of the fuel economy and to ensure sustainability of the battery’s state of charge over any given driving cycle while, in the ‘emission-reducing’ mode, the management strategy utilizes a linear quadratic regulator to optimize locally the surging emissions due to undesired engine torque transients. At the end of each emission-reducing mode, the locally optimized engine operation is driven back to match the globally optimized trajectory, i.e. the initial states of the next fuel-efficiency-improving mode. This seamless integration of the two modes will realize a reduction in the local transient emissions without losing optimality of the global fuel efficiency and sustainability of the battery’s state of charge. Experimental results demonstrate that the proposed modeling and control strategy can considerably reduce the local soot emissions of a power-split diesel hybrid electric vehicle but can still maintain a high fuel efficiency and a high state of charge of the battery.

Characterizing the energy distribution around GPR antennas

Antenna height, orientation, shielding and subsurface properties all impact GPR responses. Although the basic concepts are generally understood, clarifying the key relationships can aid interpretation. Our long term goal is to develop easily parameterized models of transmitting and receiving components of GPR systems that will provide for quantitative interpretation of data acquired with real systems. Our first step was to develop modeling capacity and response presentation tools to help with development; the initial results have been both informative and forced a better understanding of near and far field. We are using three-dimensional (3D) finite-difference time-domain (FDTD) modeling. Model results can be presented in a variety of forms. In this paper, we focus on presenting the emitted energy characteristics and use radiation pattern display format for infinitesimal dipoles, resistively loaded dipoles and shielded dipoles. Patterns are computed for a range of environments such as free-space and over loss-less half-spaces with various properties. The energy distribution patterns are presented to investigate the behavior with distance away from the transmitter feed point, and as a function of height above the ground surface. The numerical simulations provide expected insights plus demonstrate the benefit of ground-coupling and the impact of shielding on GPR responses. Further, using the total radiated energy parameter is a novel method for displaying directivity , for GPR transient emissions. • We developed a novel, systematic way for displaying UWB antenna radiation patterns. • Transition to far-field behavior is at much larger distance than previously thought. • Shields are not needed to get energy into ground but decrease energy emitted in air. • Shielding & Rx also contribute to transmitted signals. • A minimum antenna height is highly beneficial for energy going into the subsurface.

The Research Progress of Particulate Emissions from Vehicles with Gasoline Direct Injection Engines

The objective of this research is to introduce the main gasoline direct injection vehicle particulate emissions characteristics researches in the world. Many investigations of particulate sizing and number count from gasoline direct injection (GDI) vehicles at different driving cycles were performed. Lots of particulate emissions are measured for FTP-75, NEDC, HWTET, SC03, and US06 cycles and these cycles can reflect different aspects of the particulate emissions. In some papers, both engine-out and tailpipe emissions were measured. Some investigation showed high sensitivity of the particulate number or size distribution to changes with the engine control parameters including A/F, ignition timing, EOI and so on.On the whole, the particulate number during different Driving Cycle is shown along with further analysis of the transient particulate emissions. The cold start process obviously affects particulate formation. Even beyond cold start, the particulate number emissions decrease as the test progresses. The results coming from the particulate measurement system sampling directly from the exhaust showed very rapid increases in particulate emissions during engine transients.

Programa de triagem auditiva neonatal: influência do tempo de vida dos recém-nascidos na pesquisa das emissões otoacústicas transientes

OBJETIVO: este estudo visa analisar os resultados da triagem auditiva neonatal por meio das emissões otoacústicas transientes em bebês recém-nascidos em relação a diferentes tempos de vida. MÉTODO: foram analisados os prontuários de 1689 bebês avaliados no ano de 2008, em duas maternidades de Santa Catarina. Os bebês foram divididos em dois grupos: no grupo 1 a triagem foi realizada nas primeiras 24 horas após o nascimento, e no grupo 2, foi realizada entre 24 e 48 horas após o nascimento dos bebês. RESULTADOS: no grupo 1, dos 894 bebês submetidos a triagem, o índice de "falha" foi de 4,5%, equivalente a 39 bebês. No grupo 2, dos 795 bebês, 1,5% (12 bebês)"falharam no teste. Os achados demonstraram que a triagem realizada por meio das emissões otoacústicas transientes nos bebês nascidos nas primeiras 24 horas apresentaram maior índice de "falha" do que a triagem realizada após 48 horas do nascimento dos bebês. CONCLUSÃO: a triagem auditiva neonatal deve ser realizada nas maternidades, antes da alta hospitalar, porém, após as primeiras 24 horas de vida, a fim de evitar a interferência de artefatos.

Does Hyperandrogenism Affect the Otoacoustic Emissions and Medial Olivocochlear Reflex in Female Adults?

To evaluate the effects of hyperandrogenism on otoacoustic emission levels and the medial olivocochlear reflex in adult female subjects. Women have a hearing advantage over men. Otoacoustic emission levels tend to be higher in female subjects, in both newborns and adults. This discrepancy has been presumed to result from prenatal androgen exposure in male subjects. The study involved 37 polycystic ovary syndrome patients who were referred from the endocrinology department and 26 healthy volunteers. All participants who showed normal otoscopic findings, hearing thresholds, and acoustic admittance were included. All polycystic ovary syndrome patients showed biochemical signs of hyperandrogenism. Cochlear activity of participants was evaluated by means of distortion product otoacoustic emissions and transient otoacoustic emissions. The medial olivocochlear reflex was evoked with contralateral acoustic stimulation and recorded with distortion product otoacoustic emissions and transient otoacoustic emissions. Neither distortion products nor transient otoacoustic emission levels showed a statistically significant difference between the right and left ears (p > 0.05). Comparisons of distortion products and transient otoacoustic emission levels between the patient and control groups showed no statistically significant difference (p > 0.05). Comparison of the medial olivocochlear reflex response between the 2 groups also revealed no statistically significant difference (p > 0.05). Hyperandrogenism did not seem to influence otoacoustic emission levels or the medial olivocochlear reflex response in adult female subjects.

English

OBJECTIVE: To determine the incidence of Auditory impairment in the population of New born infants in a Neonatal intensive Care unit of a Tertiary Care centre using Oto-Acoustic Emissions. METHODS: 648 Newborn infants admitted to NICU in paediatric dept between June 2011 to May 2012 were taken as subjects for the study. OAE testing was done using a Portable OAE device. Each ear was tested separately and interpreted as Pass/Fail depending on the OAE response. RESULTS: Out of 648 infants 613 infants passed the OAE test after the second screening which takes the sensitivity of the test to 94.59%. Out of the 82 infants who failed the test, 22(26.8%) were preterm with Hyperbilirubinemia, 14(17.07%) were preterm with respiratory distress, 17 (20.73%) were preterm only and 29(35.36%) were term babies. CONCLUSION: Transient Otoacoustic Emissions are a very quick and Noninvasive technique, and suitable for hearing screening in infants. Two-stage screening for hearing improved identification of newborns with hearing loss in a cost effective manner.

Simultaneous conjugate observations of small‐scale structures in Saturn's dayside ultraviolet auroras: Implications for physical origins

AbstractSmall‐scale features in Saturn's dayside UV auroras are examined using images obtained on 32 Hubble Space Telescope visits close to Saturn equinox when both northern and southern emissions were simultaneously observed, allowing their interhemispheric conjugacy to be investigated. Eastward‐propagating patches in the dawn‐to‐noon sector were observed on ~70% of visits, which when present were nearly always observed both north and south. The patches were generally not closely conjugate, however, but typically displaced in local time by ~0.5–1 h, with maxima in one hemisphere falling near minima in the other. Averaged angular velocities were ~80% of rigid corotation, larger than plasma angular velocities reported in the outer magnetosphere to which the emissions are likely conjugate. We suggest the patches are associated with field‐aligned currents of eastward‐propagating ULF waves, specifically second harmonic Alfvén resonances with typical azimuthal wave numbers m ≈ 20 and plasma rest frame periods ~80 min, plausibly driven by drift‐bounce resonance with hot magnetospheric water ions. Transient dusk sector emissions of ~10–30 min duration were also observed on ~40% of visits, and found to be strictly nonconjugate, with enhancements in one hemisphere, north or south, being unaccompanied by enhancements in the other. We suggest an association with open flux tubes, and discuss one scenario where hemispheric symmetry is broken on newly opened flux tubes via the interplanetary magnetic field Y component, plausibly consistent with nonconjugate events north and south, preferential postnoon occurrence, and time scales of a few tens of minutes, though the expected relationship with the Y component remains to be established.

Investigation on Transient Emissions of a Turbocharged Diesel Engine Fuelled by HVO Blends

Investigation on Transient Emissions of a Turbocharged Diesel Engine Fuelled by HVO Blends

Transient Emissions Characteristics of a Turbocharged Engine Fuelled by Biodiesel Blends

Transient Emissions Characteristics of a Turbocharged Engine Fuelled by Biodiesel Blends

Results of an Early Hearing Detection Program

Introduction and objectivesNeonatal hearing loss is a public health problem that meets the requirements for submission to universal screening. Our objective was to analyse the results of the early hearing detection and intervention program implemented at our centre between January 2007 and December 2010. MethodsWe studied 26,717 newborns during the period mentioned, using transient otoacoustic emissions (TOAEs) for the screening. The diagnostic phase was carried out at the hearing loss department. ResultsIn our area, there were 27,935 births between January 2007 and December 2010. The screening was performed on 26,717 children. Of these, 24,173 had positive TOAEs, 1040 had no TOAEs and 1504 presented TOAEs in 1 ear with absence of TOAEs in the contralateral ear. Risk factors associated with hearing loss were found in 4674 infants. In a second phase of the program, TOAEs were given to 5156 children, of whom 4626 had positive otoacoustic emissions in both ears, 323 had no TOAEs in 1 ear and 207 failed this second phase. Of all children studied, 3.8% were referred to auditory brainstem response (ABR) testing and 26 children entered the cochlear implant program. The program achieved a coverage of 95.64%. ConclusionsThe early hearing detection and intervention program at our hospital is suitable for our environment, achieving 95.64% of coverage. We consider the relationship between effectiveness and efficiency to be positive.

Universal time control of AKR: Earth is a spin‐modulated variable radio source

AbstractAuroral kilometric radiation (AKR) is known to be transient emissions generated by rapidly accelerated electrons together with sudden auroral activation in the polar magnetosphere. In contrast, the characteristics and relationship with the auroral acceleration of rather continuous AKR emissions are not well understood. We examine the emission using long‐term data and report that the continuous AKR emission frequency changes with universal time (UT) as the Earth rotates, indicating that the Earth is a spin‐modulated variable radio source. The observed UT variation of AKR frequency means that the acceleration altitude changes periodically with planetary rotation. The observations indicate that the diurnal wobble of the tilted geomagnetic field in the solar wind flow alters the magnetosphere‐ionosphere (M‐I) coupling state in the polar magnetosphere, giving rise to periodic variation of auroral particle acceleration altitude. These observations of planetary radio wave properties provide insight into the physics of planetary particle acceleration.

Comparative evaluation of emission and fuel economy of an automotive spark ignition vehicle fuelled with methane enriched biogas and CNG using chassis dynamometer

The fuel economy and mass emission of an automotive spark ignition vehicle fuelled with the methane enriched biogas (93% CH4) and base CNG (89.14%) were evaluated using chassis dynamometer under modified Indian driving cycle (MIDC). The transient emissions were also measured with respect to time. The emissions such as CO, HC and NOx are marginally higher with the enriched biogas than base CNG. But, the experimental results indicate that the vehicle’s emission with the enriched biogas fuel meets to the BS IV Emission Norms. There is no significant change in fuel economy of the vehicle fuelled with the enriched biogas (24.11km/kg) as compared to base CNG (24.38km/kg). The experimental data indicates transient emission characteristics (CO, HC and NOx) of the vehicle with respect to time for both fuels are very higher with urban cycle (low speed) than extra urban cycle (high speed) and the findings could be useful to find out scopes of further improvement in transient emission and performance of the engine. As the methane enriched biogas gives similar performance like fossil CNG, the enriched biogas could be used as an auto fuel for spark ignition vehicles.