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Sample records for click-evoked otoacoustic emissions

  1. Temporal suppression and augmentation of click-evoked otoacoustic emissions

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Harte, James; Dau, Torsten

    2008-01-01

    This study investigates and models temporal suppression of click-evoked otoacoustic emissions (CEOAEs). This suppression-effect is created when a suppressor-click is presented close in time to a test-click. The analysis was carried out for short time-frames of short- and long-latency CEOAEs. The...... latter is defined as a CEOAE with duration greater than 20 ms, typically observed for test subjects with spontaneous otoacoustic emissions (SOAEs). Previous studies have tended to exclude these test subjects but they are incorporated here. The results from six exemplary subjects demonstrate that temporal...... temporal suppression and augmentation of CEOAEs. Recently, a feedback automatic gain control (AGC) system has been used to model CEOAE suppression. However, this system cannot account for augmentation and therefore another, dynamic nonlinear model was developed. Suppression and augmentation were modeled...

  2. Sex and Ear Differences in Spontaneous and Click-Evoked Otoacoustic Emissions in Young Adults

    Science.gov (United States)

    Snihur, Adrian W. K.; Hampson, Elizabeth

    2011-01-01

    Effects of sex and handedness on the production of spontaneous and click-evoked otoacoustic emissions (OAEs) were explored in a non-hearing impaired population (ages 17-25 years). A sex difference in OAEs, either produced spontaneously (spontaneous OAEs or SOAEs) or in response to auditory stimuli (click-evoked OAEs or CEOAEs) has been reported in…

  3. Effect of age on click-evoked otoacoustic emission A systematic review

    Institute of Scientific and Technical Information of China (English)

    Jinfeng Liu; Ningyu Wang

    2012-01-01

    OBJECTIVE: The aims of this study were to investigate the changes of the total intensity of transient evoked otoacoustic emission (TEOAE) and signal-to-noise ratio in various frequency bands as a function of aging, and to explore the role of age-related decline of cochlear outer hair cells.DATA SELECTION: Inclusion criteria: (1) Articles should involve the total TEOAE level or sig-nal-to-noise ratio. (2) The measurement and analysis system used was Otodynamics ILO analysis system (ILO88, ILO92, ILO96 or ILO292). (3) Studies involved groups of greater than 10 subjects and TEOAE results were from normally hearing ears. (4) If more papers from the same author or laboratory analyzed the same subjects, only one was used. MAIN OUTCOME MEASURES: The correlations of the age scale with the total level and sig-nal-to-noise ratio of TEOAE was determined, respectively.RESULTS: (1) TEOAE total level gradually increased until 2 months of age, and then decreased with increasing age. Significant negative correlations between total TEOAE level and age were found (r = -0.885, P = 0.000). (2) The most rapid decrease of TEOAE amplitude occurred at 1 year old. The total TEOAE level decreased about 4.25 dB SPL between 2 months to 1 year old, then about 0.26-0.52 dB SPL from 1 year to 10 years old, about 0.23 dB SPL from 11 years to 25 years old, and about 0.14 dB SPL from 26 years to 60 years old. (3) The signal-to-noise ratio in the fre-quency bands centered at 1.5, 2, 3 and 4 kHz decreased with increasing age after 2 months of age. Significant negative correlations between the signal-to-noise ratio and age were found for frequency bands ranging from 1.5 kHz to 4 kHz, with the highest correlations at 4 kHz (r = -0.890, P < 0.01), then at 3 kHz (r = -0.889, P < 0.01), at 2 kHz (r = -0.850, P < 0.01) and at 1.5 kHz (r = -0.705, P < 0.05). Conversely, a positive correlation between the signal-to-noise ratio centered at 1 kHz and age was found, but was not statistically significant (r = 0

  4. Noise-evoked otoacoustic emissions in humans

    NARCIS (Netherlands)

    Maat, B; Wit, HP; van Dijk, P

    2000-01-01

    Click-evoked otoacoustic emissions (CEOAEs) and acoustical responses evoked by bandlimited Gaussian noise (noise-evoked otoacoustic emissions; NEOAEs) were measured in three normal-hearing subjects. For the NEOAEs the first- and second-order Wiener kernel and polynomial correlation functions up to t

  5. Wiener kernel analysis of a noise-evoked otoacoustic emission

    NARCIS (Netherlands)

    van Dijk, P; Maat, A; Wit, H P

    1997-01-01

    In one specimen of the frog species, Rana esculenta, the following were measured: (1) a spontaneous otoacoustic emission; (2) a click-evoked otoacoustic emissions; and (3) a noise evoked otoacoustic emission. From the noise evoked emission response, a first-and a second-order Wiener kernel and the f

  6. Can a static nonlinearity account for the dynamics of otoacoustic emission suppression?

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Shera, Christopher A.; Harte, James; Dau, Torsten

    This study investigates whether time-dependent compression mechanisms in the cochlea are necessary to explain dynamic properties of otoacoustic emissions (OAEs). Dynamic properties of click-evoked OAEs (CEOAEs) have been observed in temporal suppression; the effect where the CEOAE magnitude is re...

  7. Efferent inhibition of otoacoustic emissions in preterm neonates

    Directory of Open Access Journals (Sweden)

    Renata Mota Mamede Carvallo

    2015-10-01

    Full Text Available ABSTRACT INTRODUCTION: Abnormalities in auditory function of newborns may occur not only because of preterm birth, but also from the use of medications and from diseases related to prematurity. OBJECTIVE: To analyze the inhibitory effect from stimulation of the olivocochlear efferent system on transient evoked otoacoustic emissions in preterm neonates, comparing these data with those from full-term neonates. METHODS: This was a prospective, cross-sectional, contemporary cohort study with 125 neonates, pooled into two groups: full-term (72 full-term neonates, 36 females and 36 males, born at 37-41 weeks of gestational age; and preterm (53 neonates, 28 males and 25 females, born at ≤36 weeks of gestational age, evaluated at the corrected gestational age of 37-41 weeks. Otoacoustic emissions were recorded using linear and nonlinear click-evoked stimuli, with and without contralateral stimulation. RESULTS: The inhibitory effect of the efferent pathway in otoacoustic emissions was different (p = 0.012 between groups, and a mean reduction of 1.48 dB SPL in full-term births and of 1.02 dB SPL in preterm births was observed for the non-linear click-evoked stimulus. CONCLUSION: The results suggest a reduced inhibitory effect of the olivocochlear efferent system on otoacoustic emissions in preterm neonates.

  8. Backward Propagation of Otoacoustic Emissions

    Institute of Scientific and Technical Information of China (English)

    HE Wenxuan; REN Tianying

    2006-01-01

    Normal mammalian ears not only detect but also generate sounds. The ear-generated sounds, I.e., otoacoustic emissions (OAEs), can be measured in the external ear canal using a tiny sensitive microphone. In spite of wide applications of OAEs in diagnosis of hearing disorders and in studies of cochlear functions, the question of how the cochlea emits sounds remains unclear. The current dominating theory is that the OAE reaches the cochlear base through a backward traveling wave. However, recently published works, including experimental data on the spatial pattern ofbasilar membrane vibrations at the emission frequency, demonstrated only forward traveling waves and no signs of backward traveling waves. These new findings indicate that the cochlea emits sounds through cochlear fluids as compression waves rather than through the basilar membrane as backward traveling waves. This article reviews different mechanisms of the backward propagation of OAEs and summarizes recent experimental results.

  9. Dynamics of spontaneous otoacoustic emissions

    Science.gov (United States)

    Bergevin, Christopher; Salerno, Anthony

    2015-12-01

    Spontaneous otoacoustic emissions (SOAEs) have become a hallmark feature in modern theories of an `active' inner ear, given their numerous correlations to auditory function (e.g., threshold microstructure, neurophysiological tuning curves), near universality across tetrapod classes, and physiological correlates at the single hair cell level. However, while several different classes of nonlinear models exist that describe the mechanisms underlying SOAE generation (e.g., coupled limit-cycle oscillators, global standing waves), there is still disagreement as to precisely which biophysical concepts are at work. Such is further compounded by the idiosyncratic nature of SOAEs: Not all ears emit, and when present, SOAE activity can occur at seemingly arbitrary frequencies (though always within the most sensitive range of the audiogram) and in several forms (e.g., peaks, broad `baseline' plateaus). The goal of the present study was to develop new signal processing and stimulation techniques that would allow for novel features of SOAE activity to be revealed. To this end, we analyzed data from a variety of different species: human, lizard, and owl. First, we explored several strategies for examining SOAE waveforms in the absence of external stimuli to further ascertain what constitutes `self-sustained sinusoids' versus `filtered noise'. We found that seemingly similar peaks in the spectral domain could exhibit key differences in the time domain, which we interpret as providing critical information about the underlying oscillators and their coupling. Second, we introduced dynamic stimuli (swept-tones, tone bursts) at a range of levels, whose interaction with SOAEs could be visualized in the time-frequency domain. Aside from offering a readily accessible way to visualize many previously reported effects (e.g., entrainment, facilitation), we observed several new features such as subharmonic distortion generation and competing pulling/pushing effects when multiple tones were

  10. Signal processing approaches on otoacoustic emissions

    OpenAIRE

    Cheng, Jun

    2000-01-01

    The recent achievement on the measurement of otoacoustic emissions (OAEs) is based on a novel technical development of digital signal processing. OAEs measured in the external ear canal are normal by-products of the active process in hearing, which was discovered by Kemp (1978). Outer hair cells (OHCs) are thought to be the active source in the generation of this energy. Signal processing methods play a crucial role in the detection of OAEs in noise and artifacts, and in the...

  11. Otoacoustic emissions measured in children diagnosed with attention-deficit/hyperactivity disorder

    Science.gov (United States)

    McFadden, Dennis; Westhafer, J. Gregory; Pasanen, Edward G.; Tucker, David M.; Carlson, Caryn L.

    2003-10-01

    Attention-deficit/hyperactivity disorder (ADHD) is generally acknowledged to be more prevalent in males than in females. Further, some precursors to ADHD appear early in life. Together these facts suggest that ADHD may be influenced by androgenic mechanisms operating early in development. This reasoning raises the question of whether the otoacoustic emissions (OAEs) of children with ADHD are masculinized. Click-evoked OAEs were measured for one click level in 8 boys and 3 girls diagnosed as ADHD/Combined, in 11 males and 5 females diagnosed as ADHD/Inattentive (IA), and in 17 male and 18 female controls. The ages of these samples ranged between 7 and 15. As in adults, the CEOAEs of the control males were weaker than those of the control females. Further, the CEOAEs of the ADHD/IA males were weaker than in the control males (a hypermasculinization) and the CEOAEs of the IA females were weaker than in the female controls (a masculinization). The CEOAEs of the Combined groups were slightly stronger (feminized) than those of the control males and females. One interpretation is that the IA subgroup of ADHD boys and girls (but not the Combined subgroup) was exposed to higher-than-normal levels of androgens sometime early in development. [Work supported by NIDCD.

  12. Spontaneous Otoacoustic Emissions in Tinnitus Patients

    Institute of Scientific and Technical Information of China (English)

    SHI Yongbing; William Martin

    2006-01-01

    Otoacoustic emissions (OAEs) are believed to be the products of active cochlear mechanics. They are generally associated with relatively intact outer hair cell function. OAEs usually decrease or become undetectable when hearing loss of cochlear origin exceeds 40-50 dB HL. Subjective tinnitus is a perception of sound without detectable corresponding source. It is most often seen in patients with hearing loss. It is also frequently seen in patients with head injuries. Studies have suggested that the prevalence of spontaneous otoacoustic emissions(SOAEs) is lower in patients with hearing loss and tinnitus than in normal population. There have also been reports on association between tinnitus and SOAEs of unusually high amplitudes, which can be controlled by aspirin administration. The current paper is a preliminary review of clinical data collected from a group oftinnitus patients in an attempt to elucidate on the relationship between SOAEs and tinnitus from a clinical point of view. Audiometric, tinnitus and SOAE data from 59 patients seen at the Oregon Health & Science University Tinnitus Clinic were retrospectively studied. Fifty-four of these 59 patients showed sensorineural hearing loss of various degrees at the time of evaluation, mostly affecting high frequencies. SOAEs were detected in 26 ears (22%) of 1 8 patients(30.5%). There was no difference in SOAE prevalence between male and female patients. SOAEs were recorded in four of the five patients whose pure tone thresholds were within normal limits up to 8000 Hz. SOAEs appeared to be recorded at a higher rate in patients whose tinnitus started following motor vehicle accidents or head injuries(5/10) than in other patients.Time course of tinnitus did not appear to affect SOAE detection rate. There were no correlations between SOAE frequency and matched tinnitus pitch or frequency of maximum hearing loss. Significance of these findings is discussed.

  13. Can components in distortion-product otoacoustic emissions be separated?

    DEFF Research Database (Denmark)

    Christensen, Anders Tornvig; W. Purcell, David; Christensen, Flemming;

    2012-01-01

    . Specifically, DPOAEs from 500 Hz to 4000 Hz were measured in 20 normal-hearing human ears, using exponentially swept, fixed-ratio primaries. Source separation by group delays relied on gating in the DPOAE latency domain, obtained by an inverse Fourier transform of DPOAE magnitude and phase. Source separation......Otoacoustic emissions are signals emitted from the cochlea, either spontaneously or evoked by stimuli. Measured with an acoustic probe sealed in the ear-canal, they reveal information about a part of the mechanism of hearing that is otherwise inaccessible. Outer hair cells in the cochlea work to...... improve hearing sensitivity by means of nonlinear amplification, which produces distortion. In the measurement of otoacoustic emissions, two tones can be delivered to the cochlea to invoke this nonlinearity and elicit the distortion-product otoacoustic emission (DPOAE). DPOAEs arise mainly from two...

  14. Distortion product otoacoustic emission fine structure of symphony orchestra musicians

    DEFF Research Database (Denmark)

    Reuter, Karen; Hammershøi, Dorte

    Otoacoustic emissions (OAE) are sounds produced by the healthy inner ear. They can be measured as low-level signals in the ear canal and are used to monitor the functioning of outer hair cells.Several studies indicate that OAE might be a more sensitive measure to detect early noise-induced hearing...... losses than puretone audiometry. The distortion product otoacoustic emission (DPOAE) fine structure is obtained when the ear is stimulated by dual tone stimuli using a high frequency resolution. It is characterized by quasi-periodic variations across frequency, as it can be observed in the hearing...

  15. Distortion product otoacoustic emission fine structure of symphony orchestra musicians

    DEFF Research Database (Denmark)

    Reuter, Karen; Hammershøi, Dorte

    2006-01-01

    Otoacoustic emissions (OAE) are sounds produced by the healthy inner ear. They can be measured as low-level signals in the ear canal and are used to monitor the functioning of outer hair cells. Many studies indicate that OAE might be a more sensitive measure to detect early noise-induced haring...... losses than pure-tone audiometry. The distortion product otoacoustic emission (DPOAE) fine structure is obtained when the ear is stiumulated by dual tone stimuli using a high frequency resolution. It is characterized by quasi-periodic variations across frequency, as it can be observed in the hearing...

  16. Fine structures in hearing thresholds and distortion product otoacoustic emissions

    DEFF Research Database (Denmark)

    Hammershøi, Dorte; Ordoñez, Rodrigo Pizarro; Torrente, Marina;

    2010-01-01

    Otoacoustic emissions (OAEs) are weak sounds that can be recorded in the external ear. They are generated by the active amplification of the outer hair cells, and are by many believed to reflect the status of the most vulnerable part of the hearing better than ordinary behavioral thresholds. Dist...

  17. Ellipsoidal reflector for measuring oto-acoustic emissions

    DEFF Research Database (Denmark)

    Epp, Bastian; Pulkki, Ville; Heiskanen, Vesa

    2014-01-01

    A truncated prolate ellipsoidal reflector having the ear canal of a listener at one focal point and large- diaphragm low-noise microphone at the other focal point is proposed for free-field recordings of oto-acoustic emissions. A prototype reflector consisting of three pieces is presented, which...

  18. Temperature dependence of anuran distortion product otoacoustic emissions

    NARCIS (Netherlands)

    Meenderink, Sebastlaan W. F.; Van Dijk, Pim

    2006-01-01

    To study the possible involvement of energy dependent mechanisms in the transduction of sound within the anuran ear, distortion product otoacoustic emissions (DPOAEs) were recorded in the northern leopard frog over a range of body temperatures. The effect of body temperature depended on the stimulus

  19. Obtaining reliable phase-gradient delays from otoacoustic emission data

    OpenAIRE

    Shera, Christopher A.; Bergevin, Christopher

    2012-01-01

    Reflection-source otoacoustic emission phase-gradient delays are widely used to obtain noninvasive estimates of cochlear function and properties, such as the sharpness of mechanical tuning and its variation along the length of the cochlear partition. Although different data-processing strategies are known to yield different delay estimates and trends, their relative reliability has not been established. This paper uses in silico experiments to evaluate six methods for extracting delay trends ...

  20. Effect of vitamin B12 deficiency on otoacoustic emissions

    OpenAIRE

    KARLI, R.; Gül, A; UĞUR, B.

    2013-01-01

    SUMMARY The aim of this study was to investigate the possible association between otoacoustic emission (OAE) values and cochlear function in patients with vitamin B12 deficiency and no evidence of symptomatic hearing loss. Two groups were studied: Group 1: patients with vitamin B12 deficiency; Group 2: a matched control group of patients with normal vitamin B12 levels. There was no evidence of symptomatic hearing loss in either group. Transiently evoked OAEs (TEOAEs) and spontaneous OAEs (SOA...

  1. Wavelet analysis demonstrates no abnormality in contralateral suppression of otoacoustic emissions in tinnitus patients

    NARCIS (Netherlands)

    Geven, Leontien I.; Wit, Hero P.; de Kleine, Emile; van Dijk, Pim

    2012-01-01

    The efferent auditory system is thought to play a role in the origin of tinnitus. Part of this system can be tested in humans with contralateral suppression of otoacoustic emissions. Stimulation of the medial olivocochlear efferent system is responsible for this reduction of otoacoustic emissions af

  2. Effects of changes in dynamic characteristics of the middle ear on transient-evoked otoacoustic emissions

    Directory of Open Access Journals (Sweden)

    Špirić Sanja

    2011-01-01

    Full Text Available Transient-evoked otoacoustic emissions are transmitted through the middle ear. The purpose of this study was to investigate the effects of dynamic properties of the transmission system on the measurability of transient otoacoustic emissions. The authors analyzed the presence of transient otoacoustic emissions in 48 children with serous otitis media regarding the tympanogram, presence and type of effusion and pure tone average findings. The results obtained in this research show the predominant absence of transient otoacoustic emissions in patients with type B tympanogram (69.1% especially if the effusion is mucoid (77.5% with the hearing loss of 15 decibel hearing level. This research shows that disorders in dynamic characteristics of the middle ear in patients with serous otitis obstruct the transmission of acoustic energy and affect the measurability of transient otoacoustic emissions, especially if the effusion is mucoid and hearing loss of 15 decibel hearing level.

  3. Music Listening Behavior, Health, Hearing and Otoacoustic Emission Levels

    OpenAIRE

    Kathleen Hutchinson Marron; Brittany Sproat; Danielle Ross; Sarah Wagner; Helaine Alessio

    2014-01-01

    This study examined the relationship between hearing levels, otoacoustic emission levels and listening habits related to the use of personal listening devices (PLDs) in adults with varying health-related fitness. Duration of PLD use was estimated and volume level was directly measured. Biomarkers of health-related fitness were co-factored into the analyses. 115 subjects ages 18–84 participated in this study. Subjects were divided into two sub-groups; PLD users and non-PLD users. Both groups c...

  4. Effects of noise overexposure on distortion product otoacoustic emissions

    DEFF Research Database (Denmark)

    de Toro, Miguel Angel Aranda

    The risk of noise-induced hearing loss (NIHL) at the workplace can be predicted according to the International Standard ISO 1999:1990. The standard is applicable to all types of noise and it is based on measurements of the total acoustic energy (LEX,8ℎ). Therefore, noises with equal energy are...... with measurements of distortion product otoacoustic emissions (DPOAE). The assumption is that a difference in the temporary changes from the stimuli may be indicative of a higher risk of NIHL. The results suggest that the risk of NIHL for low-level impulses may be predicted on an energy basis, whereas...

  5. Obtaining reliable phase-gradient delays from otoacoustic emission data.

    Science.gov (United States)

    Shera, Christopher A; Bergevin, Christopher

    2012-08-01

    Reflection-source otoacoustic emission phase-gradient delays are widely used to obtain noninvasive estimates of cochlear function and properties, such as the sharpness of mechanical tuning and its variation along the length of the cochlear partition. Although different data-processing strategies are known to yield different delay estimates and trends, their relative reliability has not been established. This paper uses in silico experiments to evaluate six methods for extracting delay trends from reflection-source otoacoustic emissions (OAEs). The six methods include both previously published procedures (e.g., phase smoothing, energy-weighting, data exclusion based on signal-to-noise ratio) and novel strategies (e.g., peak-picking, all-pass factorization). Although some of the methods perform well (e.g., peak-picking), others introduce substantial bias (e.g., phase smoothing) and are not recommended. In addition, since standing waves caused by multiple internal reflection can complicate the interpretation and compromise the application of OAE delays, this paper develops and evaluates two promising signal-processing strategies, the first based on time-frequency filtering using the continuous wavelet transform and the second on cepstral analysis, for separating the direct emission from its subsequent reflections. Altogether, the results help to resolve previous disagreements about the frequency dependence of human OAE delays and the sharpness of cochlear tuning while providing useful analysis methods for future studies. PMID:22894215

  6. Effects of salicylates and aminoglycosides on spontaneous otoacoustic emissions in the Tokay gecko

    OpenAIRE

    Stewart, Charles E; Hudspeth, A. James

    2000-01-01

    The high sensitivity and sharp frequency discrimination of hearing depend on mechanical amplification in the cochlea. To explore the basis of this active process, we examined the pharmacological sensitivity of spontaneous otoacoustic emissions (SOAEs) in a lizard, the Tokay gecko. In a quiet environment, each ear produced a complex but stable pattern of emissions. These SOAEs were reversibly modulated by drugs that affect mammalian otoacoustic emissions, the salicylates and the aminoglycoside...

  7. Modeling Stimulus-Frequency Otoacoustic Emissions in the Gecko

    Science.gov (United States)

    Bergevin, Christopher; Shera, Christopher A.

    2009-02-01

    Although lizards lack the basilar-membrane traveling waves evident in mammals, their ears produce stimulus-frequency otoacoustic emissions (SFOAEs) with latencies comparable to those measured in many mammals (1-2 ms or greater). To probe the origin of these relatively long OAE delays, we developed a model of SFOAE generation in the gecko. The model inner ear comprises a collection of linear, coupled oscillators (hair bundles and associated tectorium) whose effective damping manifests a small degree of irregularity. The model reproduces the major qualitative features of gecko SFOAEs, including their substantial delays. The SFOAE delays predicted by the model increase with the assumed sharpness of tuning, reflecting the build-up time associated with mechanical resonance.

  8. Relating psychophysical and otoacoustic emission suppression tuning curves

    Science.gov (United States)

    Digiovanni, Jeffrey J.; Zettner, Erika M.

    2001-05-01

    Psychophysical tuning curves (PTCs) are a well established method for estimating frequency selectivity in humans. PTCs are closely related to the shape of neural tuning curves. Furthermore, these two measurements are believed to represent frequency resolution processes primarily occurring in the cochlea. More recently, otoacoustic emission suppression tuning curves (STCs) have been measured and found to be characteristically similar in shape and tip frequency to PTCs (Abdala et al., 1996). STCs may represent an objective, noninvasive, measure of initial stages of cochlear tuning. The goal of this study was to compare and quantify the difference between transient evoked STCs (TE-STC) and PTCs. TE-STCs and PTCs were obtained in each normal-hearing subject with 4000-Hz probe tones. Preliminary data show that Q10 values and tip levels follow the same trend for both tuning curves. However, actual values of these parameters differ. Implications of methodological differences between these two paradigms will be discussed.

  9. Assessment evaluation of transient evoked otoacoustic emission by contralateral suppression in tinnitus patient with normal hearing

    Directory of Open Access Journals (Sweden)

    Helnaz Mokrian

    2014-01-01

    Conclusion: The suppression of the transient evoked otoacoustic emission by contralateral white noise did not reach statistically significant levels in tinnitus patients while the amplitude in control group reduced significantly.

  10. Transiently Evoked Otoacoustic Emissions in Children with Otitis Media with Effusion

    Directory of Open Access Journals (Sweden)

    Dimitris G. Balatsouras

    2012-01-01

    Full Text Available Introduction. Otitis media with effusion is a common pediatric disease whose diagnosis is based on pneumatic otoscopy, pure-tone audiometry, and tympanometry. The aim of this study was to evaluate transiently evoked otoacoustic emissions in the diagnosis of otitis media with effusion as compared to tympanometry. Patients and Methods. 38 children with bilateral otitis media with effusion were studied. 40 normal children of similar age and sex were used as controls. All subjects underwent pneumatic otoscopy, standard pure-tone audiometry, tympanometry, and transiently evoked otoacoustic emissions. Results. In the group of children with bilateral otitis media, transiently evoked otoacoustic emissions were absent in 51 ears (67%. In the remaining 25 ears (33% the mean emission amplitude was reduced, as compared to the mean value of the control group. Conclusions. Transiently evoked otoacoustic emissions should be included in the diagnostic workup of otitis media with effusion because it is a fast, reliable, and objective test. Transiently evoked otoacoustic emissions should always be used in conjunction with tympanometry, because a more meaningful interpretation of transiently evoked otoacoustic emissions measures is possible.

  11. Response level of the transient-evoked otoacoustic emissions on infants having a gastroesophageal reflux

    OpenAIRE

    Camboim, Elizângela Dias; Scharlach, Renata Coelho; Farias, Kelvânio Vitório de; Oliveira, Lívia Karla Gadêlha de; Vasconcelos, Dênis; de Azevedo, Marisa Frasson

    2011-01-01

    Introduction: The transient-evoked otoacoustic emissions (TEOAE) have been the most widespread technique to perform neonatal hearing screening. Scrutinizing their measures by way of an association with other alterations that may impair the infant's auditory system is important. Objective: Analyze the incidence and the response levels of the transient-evoked otoacoustic emissions on infants having a physiological gastroesophageal reflux disease (GERD). Method: A prospective study was performed...

  12. Otoacoustic emissions recorded in people with chronic migraine

    Institute of Scientific and Technical Information of China (English)

    Lori Cameron; Wei Sun

    2014-01-01

    Migraine, a moderate to severe chronic headache occurring on one or both sides, is a common disease affects young people. Although hearing loss in subjects with migraine is not rare, the correlation of migraine with hearing loss is not clear. In this study, we examined hearing loss in young migraine subjects to determine if migraine may be a factor in causing cochlear dysfunction. Seven college students with migraine and three age matched subjects without history of migraine were assessed using extended high frequency audiometry and distortion product otoacoustic emissions (DPOAEs). There was no significant difference in regular audiometry threshold between the migraine group and the control group. However, high frequency audiometry (9e16 kHz) showed thresholds at 25 dB nHL or higher in six out of twenty ears in the migraine group. The amplitude of DPOAEs were reduced for more than 10 dB in the migraine group in comparison with the control group. These data suggest that migraine may affect cochlear dysfunction evidenced by the reduced amplitude of DPOAE and high frequency pure-tone audiometry.

  13. Music Listening Behavior, Health, Hearing and Otoacoustic Emission Levels

    Directory of Open Access Journals (Sweden)

    Kathleen Hutchinson Marron

    2014-07-01

    Full Text Available This study examined the relationship between hearing levels, otoacoustic emission levels and listening habits related to the use of personal listening devices (PLDs in adults with varying health-related fitness. Duration of PLD use was estimated and volume level was directly measured. Biomarkers of health-related fitness were co-factored into the analyses. 115 subjects ages 18–84 participated in this study. Subjects were divided into two sub-groups; PLD users and non-PLD users. Both groups completed audiological and health-related fitness tests. Due to the mismatch in the mean age of the PLD user versus the non-PLD user groups, age-adjusted statistics were performed to determine factors that contributed to hearing levels. Age was the most significant predictor of hearing levels across listening and health-related fitness variables. PLD user status did not impact hearing measures, yet PLD users who listened less than 8 hours per week with intensities of less than 80 dBA were found to have better hearing. Other variables found to be associated with hearing levels included: years listening to PLD, number of noise environments and use of ear protection. Finally, a healthy waist-to-hip ratio was a significant predictor of better hearing, while body mass index approached, but did not reach statistical significance.

  14. The Effects of Auditory Selective Attention on Contralateral Suppression of Stimulus-Frequency Otoacoustic Emissions

    Directory of Open Access Journals (Sweden)

    Bahram Jalaee

    2011-09-01

    Full Text Available Background and Aim: To date, the function of auditory efferent system remains unclear. There is evidence that medial olivocochlear bundle receives descending input from the cortex. In this study, the effect of auditory selective attention on stimulus-frequency otoacoustic emissions (SFOAE was analyzed to investigate the modification of peripheral auditory system by auditory cortex activity in frequency specific mode.Methods: Thirty-six normal hearing adult subjects with their age ranging from 18 to 30 years (mean age: 21.9 years participated in this cross-sectional study. Contralateral suppression of stimulus-frequency otoacoustic emissions was recorded in the right ear at 2 KHz. In order to eliminate the auditory attention, subjects were instructed to read a text. Besides, in order to evaluate the effect of auditory attention on contralateral suppression, subjects were instructed to detect target tones in background noise at 1000, 2000, and 4000 KHz.Results: A significant increase at contralateral suppression of stimulus-frequency otoacoustic emissions was observed in auditory selective attention conditions (p≤0.001. The largest magnitude of stimulus-frequency otoacoustic emissions suppression was seen at 2 KHz.Conclusion: The results of this study indicated that the activities of medial olivocochlear bundle enhanced by contralateral auditory selective attention increase the magnitude of stimulus-frequency otoacoustic emissions suppression. In fact, these results provided evidence for influence of auditory cortex on the peripheral auditory system via corticofugal pathways in a frequency specific way.

  15. Transient evoked otoacoustic emission input/output function and cochlear reflectivity: experiment and model.

    Science.gov (United States)

    Sisto, Renata; Moleti, Arturo

    2008-11-01

    The complex input/output function of transient evoked otoacoustic emissions is evaluated at different stimulus levels. The experimental response functions were best fitted to the reflectivity functions predicted by theoretical one-dimensional transmission-line models in the perturbative limit. Along with the otoacoustic emission sources usually considered, linear reflection from roughness (place-fixed) and nonlinear distortion (wave-fixed), a wave-fixed scattering potential is also considered, associated with the breaking of the scale-invariance symmetry, as a new additional mechanism for otoacoustic emission generation. A good fit was obtained, across stimulus level and frequency, for roughness, and not for nonlinear distortion, nor for scale-invariance violation. The phase-gradient delay of the same transient evoked otoacoustic emissions was consistent with the latency measured using a wavelet time-frequency technique, at all stimulus levels and frequencies. The results suggest that cochlear reflectivity is dominated by a component with a rapidly rotating phase, at all stimulus levels, in apparent contradiction with the usual assumption that, at high stimulus levels, a significant contribution to the transient evoked otoacoustic response should come from nonlinear distortion. Possible interpretations of this phenomenology are critically reviewed and discussed, considering the theoretical uncertainties and the limitations of the experimental technique. PMID:19045787

  16. Effects of spontaneous otoacoustic emissions on pure-tone frequency difference limens

    DEFF Research Database (Denmark)

    Hansen, Rói; Santurette, Sébastien; Verhulst, Sarah

    2014-01-01

    Pure-tone frequency difference limens (FDLs) have been shown to vary in the vicinity of spontaneous otoacoustic emissions (SOAEs). As lower FDLs have been observed near SOAEs when measured ipsi- and contralaterally to the emission ear, it has been proposed that prolonged ongoing stimulation of ne...

  17. A pilot study of changes in otoacoustic emissions after exposure to live music

    DEFF Research Database (Denmark)

    Ordoñez, Rodrigo Pizarro; Hammershøi, Dorte; Borg, Carsten;

    2012-01-01

    Otoacoustic Emissions (TEOAE). Sound exposure was measured using a Behind the Ear Hearing aid (BTE) modified to log equivalent levels. The main observations from this study are: There are measurable changes in the auditory function after attendance to a single concert; The DPOAE measurements were more robust...

  18. Design of an Acoustic Probe to Measure Otoacoustic Emissions Below 0.5 kHz

    DEFF Research Database (Denmark)

    Christensen, Anders Tornvig; Ordoñez, Rodrigo; Hammershøi, Dorte

    2015-01-01

    Our ability to hear is reflected in low-level acoustic signals emitted from the ear. These otoacoustic emissions (OAEs) can be measured with an acoustic probe assembly coupling one or more small loudspeakers and microphones into the sealed ear canal. The electroacoustic instrumentation of...

  19. Does over-exposure modify the fine structure of distortion product otoacoustic emissions?

    DEFF Research Database (Denmark)

    Reuter, Karen; Hammershøi, Dorte

    It is investigated, whether the pattern of distortion product otoacoustic emission (DPOAE) fine structure (quasi-periodic variations across frequency) is altered by an acoustical over-exposure. DPOAE fine structures are determined in 16 normal-hearing humans using a high frequency-resolution and...

  20. Relating 2f1-f2 distortion product otoacoustic emission and equivalent rectangular bandwidth

    DEFF Research Database (Denmark)

    Christensen, Anders Tornvig; Ordoñez, Rodrigo; Hammershøi, Dorte

    2016-01-01

    To explore the extent of distortion product otoacoustic emission (DPOAE) toward low frequencies we measured in 21 normal-hearing human subjects its dependence on the ratio between evoking stimulus frequencies, f1 and f2, at 2f1-f2 distortion frequencies 88, 176 and 264 Hz. The "optimal" ratio evo...

  1. Individual cochlear delays measured with tone-burst-evoked otoacoustic emissions

    DEFF Research Database (Denmark)

    Pigasse, Gilles; Harte, James; Dau, Torsten

    Methods to estimate cochlear delay in humans have been traditionally based on either phase-derived group delays from otoacoustic emissions (OAEs), or auditory brainstem responses (ABR). These methods demonstrate large variability in cochlear delay estimates, and are derived from across subject av...

  2. Stability of the Medial Olivocochlear Reflex as Measured by Distortion Product Otoacoustic Emissions

    Science.gov (United States)

    Mishra, Srikanta K.; Abdala, Carolina

    2015-01-01

    Purpose: The purpose of this study was to assess the repeatability of a fine-resolution, distortion product otoacoustic emission (DPOAE)-based assay of the medial olivocochlear (MOC) reflex in normal-hearing adults. Method: Data were collected during 36 test sessions from 4 normal-hearing adults to assess short-term stability and 5 normal-hearing…

  3. Nonlinear time-domain cochlear model for transient stimulation and human otoacoustic emission

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Dau, Torsten; Shera, Christopher A.

    2012-01-01

    This paper describes the implementation and performance of a nonlinear time-domain model of the cochlea for transient stimulation and human otoacoustic emission generation. The nonlinearity simulates compressive growth of measured basilar-membrane impulse responses. The model accounts for reflect...

  4. Noise Levels during Aerobics and the Potential Effects on Distortion Product Otoacoustic Emissions

    Science.gov (United States)

    Torre, Peter, III; Howell, Jennifer C.

    2008-01-01

    The purpose of this study was to measure noise levels during aerobics classes and to examine how outer hair cell (OHC) function, using distortion product otoacoustic emissions (DPOAEs), may be affected by this exposure. Fifty individuals (48 women and 2 men, ages 19-41 years) participated in 50-min aerobics classes. Noise levels were measured…

  5. Response level of the transient-evoked otoacoustic emissions on infants having a gastroesophageal reflux

    Directory of Open Access Journals (Sweden)

    Camboim, Elizângela Dias

    2011-07-01

    Full Text Available Introduction: The transient-evoked otoacoustic emissions (TEOAE have been the most widespread technique to perform neonatal hearing screening. Scrutinizing their measures by way of an association with other alterations that may impair the infant's auditory system is important. Objective: Analyze the incidence and the response levels of the transient-evoked otoacoustic emissions on infants having a physiological gastroesophageal reflux disease (GERD. Method: A prospective study was performed at Santa Juliana Hospital's Otorhinolaryngology Department. 118 prematurely-born and timely-born babies, from newly-born to 6 months old, who were sent by pediatricians and gastropediatricians, participated in the study and they were divided into two groups: Study Group: 63 infants clinically diagnosed of a physiological gastroesophageal reflux disease, and Control Group: 55 infants without a physiological gastroesophageal reflux. The peripheral hearing function was evaluated by both transient-evoked otoacoustic emissions and otoscopy examinations performed by an otorhinolaryngologist. Results: The average response levels of the transient-evoked otoacoustic emissions were higher in the non-reflux group for frequency bands of 2kHz, 2.5kHz, 3kHz, 3.5kHz and 4.5kHz bilaterally, with a statistically significant difference, achieving the average values of 7.71dB and 7dB in the right ear found in the frequency bands of 2 and 4kHz, respectively. Conclusion: There was a lower incidence and a lower response level of the transient-evoked otoacoustic emissions in physiological gastroesophageal reflux children in comparison with children having no reflux.

  6. Probing cochlear tuning and tonotopy in the tiger using otoacoustic emissions

    OpenAIRE

    Bergevin, Christopher; Walsh, Edward J.; McGee, JoAnn; Shera, Christopher A.

    2012-01-01

    Otoacoustic emissions (sound emitted from the ear) allow cochlear function to be probed noninvasively. The emissions evoked by pure tones, known as stimulus-frequency emissions (SFOAEs), have been shown to provide reliable estimates of peripheral frequency tuning in a variety of mammalian and non-mammalian species. Here, we apply the same methodology to explore peripheral auditory function in the largest member of the cat family, the tiger (Panthera tigris). We measured SFOAEs in 9 unique ear...

  7. The influence of probe level on the tuning of stimulus frequency otoacoustic emissions and behavioral test in human

    OpenAIRE

    Wang, Yao; Gong, Qin; Zhang, Tao

    2016-01-01

    Background Frequency selectivity (FS) of the auditory system is established at the level of the cochlea and it is important for the perception of complex sounds. Although direct measurements of cochlear FS require surgical preparation, it can also be estimated with the measurements of otoacoustic emissions or behavioral tests, including stimulus frequency otoacoustic emission suppression tuning curves (SFOAE STCs) or psychophysical tuning curves (PTCs). These two methods result in similar est...

  8. Otoacoustic emissions as an instrument of epidemiological surveillance in the health of the workers

    Directory of Open Access Journals (Sweden)

    Oliveira, Priscila Feliciano de

    2011-10-01

    Full Text Available Introduction: The noise is a harmful agent to the hearing, being frequent in urban and work environments. Among the structures of the hearing system, the outer hair cells are the first to be injured, and otoacoustic emissions identify minimal cochlear alterations. Objective: Analyze cochlear alterations with otoacoustic emissions transient evoked in individuals exposed to combined risk: noise and chemical products. Method: 49 workers of a cement company participated of the research, aged between 19 and 49 years old, exposure time of at least two years and normal hearing thresholds. Was performed an anamnesis and otoacoustic emissions before and post work activity. The results of the exam were related with the variable: time of exposure to the noise, age, exposure to chemical products and sound habits. The statistical tests used were: T of Student, chi-squared Pearson test and Fisher's exact test and is characterized by a prospective clinical study. Results: At the first testing, had presence of emissions in all of the workers. The average of amplitude is of 10,22 dBSPL in the right ear and 9,48 dBSPL in the left ear. In the second testing there were a variation of 0,69 dBSPL in the lef ear and 0,42 dBSPL in the right ear, of which 79,6% of individuals had presence of emission bilaterally and 20,4% absence in at least one ear. Analyzing the relation between variations of emissions with the variable was not observed statistically significant data. Conclusion: The otoacoustic emissions in the workers health search to prevent the damage to the hearing system through cochlear changings.

  9. Effects of Low-Frequency Biasing on Otoacoustic and Neural Measures Suggest that Stimulus-Frequency Otoacoustic Emissions Originate Near the Peak Region of the Traveling Wave

    OpenAIRE

    Lichtenhan, Jeffery T.

    2011-01-01

    Stimulus-frequency otoacoustic emissions (SFOAEs) have been used to study a variety of topics in cochlear mechanics, although a current topic of debate is where in the cochlea these emissions are generated. One hypothesis is that SFOAE generation is predominately near the peak region of the traveling wave. An opposing hypothesis is that SFOAE generation near the peak region is deemphasized compared to generation in the tail region of the traveling wave. A comparison was made between the effec...

  10. Simultaneous measurement of auditory-steady-state responses and otoacoustic emissions to estimate peripheral compression

    DEFF Research Database (Denmark)

    Sanchez Lopez, Raul; Epp, Bastian

    2016-01-01

    outer hair cells in the inner ear play an important role in the compressive nonlinearity, it is desirable to selectively obtain information about the inner ear. In the current study, the signal in the ear canal present during ASSR measurements is utilized to extract sinusoidally-amplitude modulated...... otoacoustic emissions (SAMOAEs). It is hypothesized that the stimulus used to evoke ASSRs will cause acoustic energy to be reflected back from the inner ear into the ear canal, where it can be picked up as an otoacoustic emission (OAE) and provide information about cochlear processing. Results indicate that...... SAMOAE in connection with ASSR may be possible by a proposed method to minimize the distortion. The ability to evaluate SAMOAE over a large input level range during ASSR measurement will provide information about the state of the peripheral auditory system without the need of additional measurement time....

  11. High frequency hearing thresholds and product distortion otoacoustic emissions in cystic fibrosis patients,

    Directory of Open Access Journals (Sweden)

    Lucia Bencke Geyer

    2015-12-01

    Full Text Available ABSTRACT INTRODUCTION: The treatment of patients with cystic fibrosis involves the use of ototoxic drugs, mainly aminoglycoside antibiotics. Due to the use of these drugs, fibrocystic patients are at risk of developing hearing loss. OBJECTIVE: To evaluate the hearing of patients with cystic fibrosis by High Frequency Audiometry and Distortion Product Otoacoustic Emissions. METHODS: Cross-sectional study. The study group consisted of 39 patients (7-20 years of age with cystic fibrosis and a control group of 36 individuals in the same age group without otologic complaints, with normal audiometric thresholds and type A tympanometric curves. High Frequency Audiometry and Distortion Product Otoacoustic Emissions tests were conducted. RESULTS: The study group had significantly higher thresholds at 250, 1000, 8000, 9000, 10,000, 12,500, and 16,000 Hz (p = 0.004 as well as higher prevalence of otoacoustic emission alterations at 1000 and 6000 Hz (p = 0.001, with significantly lower amplitudes at 1000, 1400, and 6000 Hz. There was a significant association between alterations in hearing thresholds in High Frequency Audiometry with the number of courses of aminoglycosides administered (p = 0.005. Eighty-three percent of patients who completed more than ten courses of aminoglycosides had hearing loss in High Frequency Audiometry. CONCLUSION: A significant number of patients with cystic fibrosis who received repeated courses of aminoglycosides showed alterations in High Frequency Audiometry and Distortion Product Otoacoustic Emissions. The implementation of ten or more aminoglycoside cycles was associated with alterations in High Frequency Audiometry.

  12. Distortion product otoacoustic emission phase and component analysis in human newborns

    OpenAIRE

    Abdala, Carolina; Dhar, Sumitrajit

    2010-01-01

    Apical distortion product otoacoustic emissions (DPOAEs) are comprised of at least two components, as evidenced by the interference pattern of alternating maxima and minima known as fine structure. DPOAE fine structure is produced by the shifting phase relationship in the ear canal, between the generator and characteristic frequency (CF) component of the response. Each component arises from a different cochlear region and, according to theory, reflects a distinct generation mechanism. The ana...

  13. Influence of acute hyperglycemia on otoacoustic emissions and the medial olivocochlear reflexa)

    OpenAIRE

    Jacobs, Peter G.; Konrad-Martin, Dawn; Mcmillan, Garnett P.; McDermott, Daniel; Fausti, Stephen A.; Kagen, David; Wan, Eric A.

    2012-01-01

    Stimulus-frequency (SF) otoacoustic emission (OAE) amplitude and the amplitude of medial olivocochlear (MOC) inhibition of SF OAEs for ipsilateral, contralateral and bilateral MOC reflex elicitors were recorded in six subjects with type 2 diabetes during a glucose tolerance test (GTT). Five of the six subjects were tested twice for a total of 11 trials and three subjects were tested in a control experiment. During the GTT experiment, the subjects’ blood glucose was elevated from a euglycemic ...

  14. Long-Term Effects of Acoustic Trauma on Electrically Evoked Otoacoustic Emission

    OpenAIRE

    Halsey, Kärin; Fegelman, Karen; Raphael, Yehoash; Grosh, Karl; Dolan, David F.

    2005-01-01

    Electrically evoked otoacoustic emissions (EEOAEs) are sounds measured in the ear canal when alternating current (AC) stimulation is passed into the cochlea. These sounds are attributed to the motile responses of outer hair cells (OHCs). The EEOAE has characteristic amplitude, phase, and fine structure. Multicomponent analysis of the EEOAE shows short (SDC) and long delay components (LDC) that are thought to originate from OHCs near the AC stimulating site and from OHCs at more remote locatio...

  15. Transient evoked otoacoustic emissions testing for screening of sensorineural deafness in puppies

    OpenAIRE

    McBrearty, A; J. Penderis

    2011-01-01

    Background: Transient evoked otoacoustic emissions (TEOAE) are widely used for human neonatal deafness screening, but have not been reported for clinical use in dogs. Hypothesis/Objectives: To investigate the feasibility of TEOAE testing in conscious puppies and the ability of TEOAE testing to correctly identify deaf and hearing ears, as defined by brainstem auditory evoked response (BAER). Animals: Forty puppies from 10 litters. Methods: Prospective study on puppies presented ...

  16. Distortion Product Otoacoustic Emissions: A Tool for Hearing Assessment and Scientific Study

    OpenAIRE

    Abdala, Caroline; Visser-Dumont, Leslie

    2001-01-01

    Distortion product otoacoustic emissions (DPOAEs) reflect outer hnir cell integrity and cochlear function. When used appropriately in the audiology clinic, they are an effective diagnostic tool and can detect hearing loss with accuracy. DPOAEs are easily and rapidly recorded in newborns and children, and provide basic hearing screening information as well as detailed diagnostic information in cases of suspected hearing loss. In the past decade, solid guidelines hnve been established to select...

  17. Community based universal neonatal hearing screening by health visitors using otoacoustic emissions

    OpenAIRE

    Owen, M.(School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom); Webb, M.; Evans, K.

    2001-01-01

    OBJECTIVES—To carry out a pilot study to test the feasibility of health visitors (HVs) performing neonatal otoacoustic emissions (OAE) hearing screening in the community using Echoport ILO288 and to evaluate its acceptability to parents and HVs.
DESIGN—Prospective cohort study.
SETTING—Local health centres and babies' homes in urban and rural settings in West Gloucestershire.
PARTICIPANTS—Twelve HVs, 683 babies, and their parents.
MAIN OUTCOME MEASURES—Coverage rate, a...

  18. Modification of otoacoustic emissions following ear-level exposure to MP3 player music.

    Science.gov (United States)

    Bhagat, Shaum P; Davis, Anne M

    2008-12-01

    The purpose of this study was to examine if a pre-determined exposure level and duration of MP3 player music would result in significant changes in cochlear function when measured with audiometric and physiological methods. Distortion-product otoacoustic emissions (DPOAEs), synchronized spontaneous otoacoustic emissions (SSOAEs), and hearing thresholds were measured in 20 normal-hearing adults before and after a 30-minute MP3 player music exposure. DPOAEs were acquired with 65/45 dB SPL primary tones (f(2)=0.842-7.996 kHz) with a frequency resolution of 8 points/octave. A probe microphone system recorded ear-canal music levels and was used to equalize levels at approximately 85 dBC across individuals during the music presentation. Comparison of pre- and post-exposure measurements revealed no significant differences in hearing thresholds, but DPOAE levels in half-octave bands centered from 1.4-6.0 kHz were significantly reduced following the music exposure. Post-exposure shifts in SSOAE frequency and level were highly variable in individuals identified with SSOAEs. The results for the exposure conditions explored in this study indicate that changes in otoacoustic emissions may precede the development of music-induced hearing threshold shifts. PMID:19085399

  19. Effects of salicylates and aminoglycosides on spontaneous otoacoustic emissions in the Tokay gecko.

    Science.gov (United States)

    Stewart, C E; Hudspeth, A J

    2000-01-01

    The high sensitivity and sharp frequency discrimination of hearing depend on mechanical amplification in the cochlea. To explore the basis of this active process, we examined the pharmacological sensitivity of spontaneous otoacoustic emissions (SOAEs) in a lizard, the Tokay gecko. In a quiet environment, each ear produced a complex but stable pattern of emissions. These SOAEs were reversibly modulated by drugs that affect mammalian otoacoustic emissions, the salicylates and the aminoglycoside antibiotics. The effect of a single i.p. injection of sodium salicylate depended on the initial power of the emissions: ears with strong control SOAEs displayed suppression at all frequencies, whereas those with weak control emissions showed enhancement. Repeated oral administration of acetylsalicylic acid reduced all emissions. Single i.p. doses of gentamicin or kanamycin suppressed SOAEs below 2.6 kHz, while modulating those above 2.6 kHz in either of two ways. For ears whose emission power at 2.6-5.2 kHz encompassed more than half of the total, individual emissions displayed facilitation as great as 35-fold. For the remaining ears, emissions dropped to as little as one-sixth of their initial values. The similarity of the responses of reptilian and mammalian cochleas to pharmacological intervention provides further evidence for a common mechanism of cochlear amplification. PMID:10618439

  20. Comparison of transient and distortion-product otoacoustic emissions during the luteal and follicular phases of the menstrual cycle.

    Science.gov (United States)

    Gurbuzler, Levent; Yelken, Kursat; Aladag, Ibrahim; Eyibilen, Ahmet; Koc, Sema

    2012-08-01

    We conducted a study to examine cochlear activity in women with a naturally occurring menstrual cycle by measuring transient otoacoustic emissions (TOAEs) and distortion-product otoacoustic emissions (DPOAEs). Our study population was made up of 11 women aged 20 to 40 years (mean: 35.6) who were not taking a contraceptive medication or hormone therapy. Measurements of TOAEs and DPOAEs were made during both the follicular phase and the luteal phase of the menstrual cycle. We found no statistically significant difference in any of the TOAE amplitude values between the two phases. Although a sharp decrease at the 0.75 kHz frequency was seen in DPOAEs during both phases, none of the amplitude values in the tested frequencies were significantly different between the two phases. The absence of TOAE and DPOAE amplitude changes suggests that it is unnecessary to take into account the phase of the menstrual cycle when interpreting the results of otoacoustic emissions testing. PMID:22930081

  1. A STUDY OF HEARING EVALUATION FOR NEONATES WITH HYPERBILIRUBINEMIA USING OTOACOUSTIC EMISSION AND BRAIN STEM AUDITORY EVOKED RESPONSE

    Directory of Open Access Journals (Sweden)

    Poornima

    2014-03-01

    Full Text Available Jaundice is one of the most common problems occurring in newborns. Although most of jaundiced patients are normal; because of the bilirubin toxicity, high serum levels can lead to kernicterus. It is important to identify and evaluate the jaundice early to prevent complications like bilirubin encephalopathy leading to hearing loss. Such early detection is possible only if some form of routine screening is used, one of which is otoacoustic emission. By detecting the hearing loss in time with screening methods we can ensure normal language development by appropriate intervention like hearing aids and infant stimulation. In this study otoacoustic emission will be followed by brain stem auditory evoked response and the results will be analyzed to look for the effectiveness of using otoacoustic emission for mass screening. METHODOLOGY: after obtaining approval and clearance from the institutional ethics committee this study included 105 children which satisfied the inclusion criteria. A standard case record was maintained for each subject. The neonate was subjected to otoacoustic emission just before discharge from the hospital. Otoacoustic emission was followed by brain stem auditory evoked response and the results compiled. Result of brain stem auditory evoked response was taken as gold standard and the results were analyzed. RESULTS: Abnormal OAE changes were seen in 6 and abnormal BERA was seen in 9 babies out of a total of 105 babies tested with hyperbilirubinemia. CONCLUSION: use of otoacoustic emissions as initial screening test provides as easy, cost effective and quick method to detect infants with hearing loss. As it is less invasive and less time consuming than BERA, dpOAE can be used as initial screening method for hearing loss in infants with BERA being reserved for infants that fail dpOAE.

  2. Continued Maturation of the Click-Evoked Auditory Brainstem Response in Preschoolers

    Science.gov (United States)

    Spitzer, Emily; White-Schwoch, Travis; Carr, Kali Woodruff; Skoe, Erika; Kraus, Nina

    2016-01-01

    Background Click-evoked auditory brainstem responses (ABRs) are a valuable tool for probing auditory system function and development. Although it has long been thought that the human auditory brainstem is fully mature by age 2 yr, recent evidence indicates a prolonged developmental trajectory. Purpose The purpose of this study was to determine the time course of ABR maturation in a preschool population and fill a gap in the knowledge of development. Research Design Using a cross-sectional design, we investigated the effect of age on absolute latencies, interwave latencies, and amplitudes (waves I, III, V) of the click-evoked ABR. Study Sample A total of 71 preschoolers (ages 3.12–4.99 yr) participated in the study. All had normal peripheral auditory function and IQ. Data Collection and Analysis ABRs to a rarefaction click stimulus presented at 31/sec and 80 dB SPL (73 dB nHL) were recorded monaurally using clinically-standard recording and filtering procedures while the participant sat watching a movie. Absolute latencies, interwave latencies, and amplitudes were then correlated to age. Results Developmental changes were restricted to absolute latencies. Wave V latency decreased significantly with age, whereas wave I and III latencies remained stable, even in this restricted age range. Conclusions The ABR does not remain static after age 2 yr, as seen by a systematic decrease in wave V latency between ages 3 and 5 yr. This finding suggests that the human brainstem has a continued developmental time course during the preschool years. Latency changes in the age 3–5 yr range should be considered when using ABRs as a metric of hearing health. PMID:25597458

  3. Comparison of cochlear delay estimates using otoacoustic emissions and auditory brainstem responses

    DEFF Research Database (Denmark)

    Harte, James; Pigasse, Gilles; Dau, Torsten

    2009-01-01

    Different attempts have been made to directly measure frequency specific basilar membrane (BM) delays in animals, e.g., laser velocimetry of BM vibrations and auditory nerve fiber recordings. The present study uses otoacoustic emissions (OAEs) and auditory brainstem responses (ABRs) to estimate B...... synaptic delays. This allows a comparison between individual OAE and BM delays over a large frequency range in the same subjects, and offers support to the theory that OAEs are reflected from a tonotopic place and carried back to the cochlear base via a reverse traveling wave....

  4. Changes in distortion product oto-acoustic emissions after exposure to continuous and impulsive noise

    DEFF Research Database (Denmark)

    de Toro, Miguel Angel Aranda; Ordoñez, Rodrigo Pizarro; Hammershøi, Dorte

    Temporary changes in hearing of the subjects were monitored with distortion product otoacoustic emissions (DPOAEs) after control sound exposures in a laboratory. The objectives of the experiment was to investigate whether the +5 dB penalty for impulsiveness used in international standards and...... legislation correlates to a higher risk of hearing damage. Subjects were exposed to two types of binaural recordings consisting of a continuous broad-band noise-exposure normalized to LEX,8h = 80 dBA and the interaction of the previous stimulus with a noise of impulsive character normalized to LEX,8h = 75 + 5...

  5. Changes in distortion product oto-acoustic emissions after exposure to continuous and impulsive noise

    DEFF Research Database (Denmark)

    de Toro, Miguel Angel Aranda; Ordoñez, Rodrigo Pizarro; Hammershøi, Dorte

    Temporary changes in the hearing of human subjects were monitored with distortion product otoacoustic emissions (DPOAEs) after control sound exposures in a laboratory. The objectives of the experiment were to investigate whether the +5~dB penalty for impulsiveness used in international standards...... and legislation correlates to a higher risk of hearing damage. Subjects were exposed to two types of binaural recordings consisting of a continuous broad-band noise-exposure normalized to LEX,8h = 80~dB and the interaction of the previous stimulus with a noise of impulsive character normalized to LEX...

  6. Recovery of distortion product otoacoustic emissions (DPOAE) after impulse vs. continuous equal-energy exposures

    DEFF Research Database (Denmark)

    de Toro, Miguel Angel Aranda; Ordoñez, Rodrigo Pizarro; Reuter, Karen;

    2008-01-01

    impulse and continuous noise. Noise exposures are normalized to have the same energy (LAeq,8h= 80dB). The effects in the hearing of the subjects are monitored by measuring the recovery of the distortion product otoacoustic emissions (DPOAE) with high-time resolution. The results can be used to investigate...... the validity of current assessment methods and descriptors of the temporal characteristics of sound exposures and their relation to the temporal effects produced on the human hearing as well as investigating selected issues that may lead to possible improvements or alternative measuring methods. [Work...... supported by the Danish Research Council for Technology and Production.]...

  7. Otoacoustic emissions from the cochlea as a convenient model for investigation of convectively unstable nonlinear systems

    Science.gov (United States)

    Mills, David

    2005-03-01

    Two tones introduced into the ear canal result in acoustic emissions at distortion product frequencies. Evidence suggests that the nonlinearity responsible for these distortion product otoacoustic emissions is the saturating response of hair cell transducer channels. Emissions from the normal mammalian cochlea are particularly strong and can be detected at very low sound levels. This, and other evidence, suggests the existence in mammals of a ``cochlear amplifier'' involving physical amplification of the traveling wave/basilar membrane motion driving hair cell transduction channels. A feed-back or feed-forward process equivalent to a convective instability seems required. The nonlinearity is essential in limiting amplification at high sound levels, thereby providing necessary range compression. Analysis focuses on observed input-output, or ``growth,'' functions, defined by the measurement of the amplitude of emission components as a function of varying stimulus levels with fixed stimulus frequencies. Typical growth functions demonstrate the complexity of the response, and restrict potential models of the system.

  8. Evaluation of Distortion and Transient Evoked Otoacoustic Emission in Tinnitus Patients with Normal Hearing

    Directory of Open Access Journals (Sweden)

    Helnaz Mokrian

    2014-01-01

    Full Text Available Introduction: Tinnitus is a perception of sound without external source. The exact etiology of tinnitus is not fully understood, although some researchers believe that the condition usually starts in the cochlea. The aim of this study was to determine the potential contribution of outer hair cell dysfunction to chronic tinnitus, by application of Distortion-Product Evoked Otoacoustic Emission (DPOAE and Transient Evoked Otoacoustic Emission (TEOAE and also to determine the relationship between tinnitus loudness and the amplitude of these two potentials.   Materials and Methods: This study was conducted on 20 tinnitus patients aged 20–45 years and 20 age- and gender-matched control subjects. DPOAE and TEOAE were performed on each subject.   Results: The difference in the amplitudes of TEOAE between the two groups was not significantly different (P=0.08, but the amplitude of DPOAE in patients with tinnitus was significantly lower than the corresponding value in the control subjects (P=0.01. There was no correlation between tinnitus loudness and the amplitudes of neither DPOAE nor TEOAE.   Conclusion:  Abnormal findings in the DPOAE of tinnitus sufferers suggest some form of cochlear dysfunction in these patients. As there was no correlation between the amplitude of the recorded potentials and tinnitus loudness, factors other than cochlear dysfunction may also influence the loudness of tinnitus.

  9. Optimizing swept-tone protocols for recording distortion-product otoacoustic emissions in adults and newborns.

    Science.gov (United States)

    Abdala, Carolina; Luo, Ping; Shera, Christopher A

    2015-12-01

    Distortion-product otoacoustic emissions (DPOAEs), which are routinely used in the audiology clinic and research laboratory, are conventionally recorded with discrete tones presented sequentially across frequency. However, a more efficient technique sweeps tones smoothly across frequency and applies a least-squares-fitting (LSF) procedure to compute estimates of otoacoustic emission phase and amplitude. In this study, the optimal parameters (i.e., sweep rate and duration of the LSF analysis window) required to record and analyze swept-tone DPOAEs were tested and defined in 15 adults and 10 newborns. Results indicate that optimal recording of swept-tone DPOAEs requires use of an appropriate analysis bandwidth, defined as the range of frequencies included in each least squares fit model. To achieve this, the rate at which the tones are swept and the length of the LSF analysis window must be carefully considered and changed in concert. Additionally, the optimal analysis bandwidth must be adjusted to accommodate frequency-dependent latency shifts in the reflection-component of the DPOAE. Parametric guidelines established here are equally applicable to adults and newborns. However, elevated noise during newborn swept-tone DPOAE recordings warrants protocol adaptations to improve signal-to-noise ratio and response quality. PMID:26723333

  10. Stimulus-frequency otoacoustic emissions in human newborns.

    Science.gov (United States)

    Kalluri, Radha; Abdala, Carolina

    2015-01-01

    This study presents the first reported measurements of stimulus frequency emissions (SFOAEs) in 15 human newborns and compares their magnitudes and phase-gradient delays to those reported in adults. SFOAEs in newborns were measured at stimulus levels as low as 15 dB sound pressure level (SPL). Responses were compared between adults and newborns at stimulus levels where SFOAEs in both age groups demonstrated approximately linear growth (<40 dB SPL for newborns, <25 dB SPL for adults). Neonates had adult-like SFOAE delays when compared in this fashion, which compensates for newborn middle ear inefficiencies. PMID:25618103

  11. Spontaneous otoacoustic emissions in the European edible frog (Rana esculenta): spectral details and temperature dependence.

    Science.gov (United States)

    van Dijk, P; Wit, H P; Segenhout, J M

    1989-11-01

    Spontaneous otoacoustic emissions were recorded in 41 ears of 29 European edible frogs (Rana esculenta). Emission frequencies ranged from 450 to 1350 Hz. The distribution of frequencies shows two distinct populations: one above and one below 1 kHz. With one exception, a maximum number of two emissions were recorded per ear, each in a different population. An amplitude distribution of a frog emission was sampled, from which it was concluded that the emission is generated by an active oscillator. The spectral width of an emission ranged from 1 to 200 Hz (average 38 Hz). There was negative correlation between sound pressure level of an emission and spectral width. In 4 frogs the dependence of emission power and frequency on temperature was investigated. An emission could be 'switched on and off' within a few degrees centigrade. At temperatures below the switching interval no emission was recorded; for higher temperatures emission power showed no dependence on temperature. Frequency increased with temperature (Q10 = 1.1 to 1.3). This yields a mismatch with temperature dependence of best frequencies of auditory fibers. The consequences of this mismatch are discussed. PMID:2691473

  12. Compensating for Deviant Middle Ear Pressure in Otoacoustic Emission Measurements, Data, and Comparison to a Middle Ear Model

    NARCIS (Netherlands)

    Hof, Janny R.; de Kleine, Emile; Avan, Paul; Anteunis, Lucien J. C.; Koopmans, Peter J.; van Dijk, Pim

    2012-01-01

    Objective: Deviant middle ear pressure has a negative effect on the forward and backward transmission of stimulus and emissions through the middle ear. Resolving this deviant middle ear pressure is expected to lead to better middle ear transmission and, as a result of this, stronger otoacoustic emis

  13. Auto-inflammatory challenge of the endolymphatic sac - Cochlear damage measured by distortion product oto-acoustic emissions

    DEFF Research Database (Denmark)

    Larsen, Michael; Friis, Morten; Karlsen, Charlotte Vestrup;

    2015-01-01

    CONCLUSION: Twenty-five rats were challenged by an immunologic attack of the endolymphatic sac. After 6 months, distortion product oto-acoustic emissions (DPOAE) revealed a dysfunction of the outer hair cells and immunological active cells were observed in the endolymphatic sac. This information ...

  14. Effects of background noise on transiently evoked otoacoustic emissions in newborn hearing screening

    Directory of Open Access Journals (Sweden)

    Chandrakant Vishwakarma

    2015-01-01

    Full Text Available Introduction: Newborn hearing screening program is one of the services offered in Neonatal Intensive Care Units (NICU by most of the neonatologist today. Aim of the Study: Present study aimed to investigate the ambient noise levels which allow successful transient evoked otoacoustic emission testing. Method: 25 normal hearing neonates (group 1 and 25 normal hearing adults (group 2 participated in the study. Both groups were tested at 30 dB sound pressure level (SPL, 40 dB SPL and 50 dB SPL noise levels. Results and Discussion: Tests results showed with increase in noise levels number of passing subjects decreased and also testing was done at times more than once. Conclusion: Tester should take care of noise levels while doing the test in NICU, which can give false negative responses.

  15. Separating medial olivocochlear from acoustic reflex effects on transient evoked otoacoustic emissions in unanesthetized mice

    Science.gov (United States)

    Xu, Yingyue; Cheatham, Mary Ann; Siegel, Jonathan

    2015-12-01

    Descending neural pathways in the mammalian auditory system are believed to modulate the function of the peripheral auditory system [3, 8, 10]. These pathways include the medial olivocochlear (MOC) efferent innervation to the cochlear outer hair cells (OHCs) and the acoustic reflex pathways mediating middle ear muscle (MEM) contractions. The MOC effects can be monitored noninvasively using otoacoustic emissions (OAEs) [5, 6], which are acoustic byproducts of cochlear function [7]. In this study, we applied a sensitive method to determine when and to what degree contralateral MEM suppression contaminated MOC efferent effects on TEOAEs in unanesthetized mice. The lowest contralateral broadband noise evoking MEM contractions varied across animals. Examples of potential MOC-mediated TEOAE suppression with contralateral noise below MEM contraction thresholds were seen, but this behavior did not occur in the majority of cases.

  16. Relation of distortion product otoacoustic emission and tinnitus in normal hearing patients: A pilot study

    Directory of Open Access Journals (Sweden)

    Datt Modh

    2014-01-01

    Full Text Available Introduction: Tinnitus, the perception of the sound in the absence of an external acoustic source, disrupts the daily life 1 out of every 200 adults, yet its physiological basis remains largely a mystery. The generation of tinnitus is commonly linked with the impaired functioning of the outer hair cells (OHC inside the cochlea. Otoacoustic emissions are the objective test used to assess their activity. Objective: The objective of the investigation was to study the features of Distortion product OtoAcoustic emissions (DPOAE in a group of tinnitus patients with normal hearing and to find out whether there is any difference in DPOAE findings in the tinnitus patients with normal hearing and in persons with normal hearing with no complaint of tinnitus. Materials and Methods: The participants consisted of two groups. The subject group consisted of 16 ears of patients, in which 6 subjects were having tinnitus in both ears while 4 subjects were having tinnitus only in one ear. All subjects were aged between 20 to 60 years with complaint of tinnitus with audiometrically normal hearing. Control group was comprised of 16 audiometrically normal hearing ears of persons who were age and gender matched with the subject groups and had no complaint of tinnitus. Both the subject group as well as control group was subjected for DPOAE test. Findings of both the groups were compared using the unpaired t test. Result and conclusion: It was observed that the amplitudes of DPOAE were significantly lower in tinnitus patients than that of persons without complaint of tinnitus, at a frequency of 1281-1560, 5120-6250, 7243-8837 Hz, which imply that decrease of DPOAEs amplitudes may be related to the presence of tinnitus. It can be concluded that there is association between tinnitus and reduced OHC activity which indicate the OHC of cochlea are involved in the generation of tinnitus.

  17. Distortion-product otoacoustic emission reflection-component delays and cochlear tuning: Estimates from across the human lifespan

    DEFF Research Database (Denmark)

    Abdala, Carolina; Guérit, François; Luo, Ping; Shera, Christopher A.

    2014-01-01

    A consistent relationship between reflection-emission delay and cochlear tuning has been demonstrated in a variety of mammalian species, as predicted by filter theory and models of otoacoustic emission (OAE) generation. As a step toward the goal of studying cochlear tuning throughout the human...... lifespan, this paper exploits the relationship and explores two strategies for estimating delay trends—energy weighting and peak picking—both of which emphasize data at the peaks of the magnitude fine structure. Distortion product otoacoustic emissions (DPOAEs) at 2f1f2 were recorded, and their reflection...... yielding slightly shorter delays and the latter somewhat smaller confidence intervals. Delay and tuning estimates from young adults roughly match those obtained from SFOAEs. Although the match is imperfect, reflection-component delays showed the expected bend (apical-basal transition) near 1 k...

  18. Distortion product otoacoustic emissions provide clues to hearing mechanisms in the frog

    Science.gov (United States)

    Vassilakis, Pantelis; Narins, Peter M.

    2003-10-01

    Cubic distortion product otoacoustic emissions (DPOAEs) were recorded from 10 Rana pipiens and 10 Rana catesbeiana, 5 males and 5 females each. The I/O curves obtained from the amphibian papilla (AP) of both species are very similar to the respective mammalian curves, indicating that, like in the mammalian cochlea, there may be an amplification process active in the frog AP. The DPOAE level dependence on primary levels is also similar to the mammalian case, suggesting a mechanical structure in the frog inner ear may be functioning analogously to the mammalian basilar membrane. DPOAE audiograms were obtained for primary frequencies spanning the animals hearing range and levels determined by the previous experiments. R. catesbeiana produce stronger emissions than R. pipiens and, consistent with previously reported sexual dimorphism in the mammalian and anuran auditory systems, females from both species produce stronger emissions than males. Additionally, the 2f1-f2 DPOAE is generated primarily at the DPOAE frequency place, while the 2f2-f1 DPOAE is generated primarily at a frequency place between the primaries. This difference in mammalian and frog DPOAEs may be linked to an anatomical difference that results in the acoustic energy following opposite paths through the mammalian and frog inner ears. [Work supported by NIH Grant No. DC-00222 to Peter M. Narins.] a)Currently at De Paul Univ., School of Music, Chicago, IL 60614.

  19. Otoacoustic emission (OAE)-based measurement of the functioning of the human cochlea and the efferent auditory system

    OpenAIRE

    Mishra, Srikanta Kumar

    2010-01-01

    The discovery of otoacoustic emissions (OAE) has advanced our understanding of cochlear mechanics and the efferent auditory system. OAE are sounds generated within normal cochlea either spontaneously or in response to stimulation. The ability to measure OAE non-invasively, objectively and quickly makes a powerful tool to probe cochlear mechanics. Stimulation of the efferent auditory system causes changes in cochlear amplification processes and hence changes characteristics of OAE. Contrala...

  20. Distortion-product otoacoustic-emission suppression tuning in human infants and adults using absorbed sound power

    OpenAIRE

    Keefe, Douglas H.; Abdala, Carolina

    2011-01-01

    The greatest difference in distortion product otoacoustic emission (DPOAE) suppression tuning curves (STCs) in infant and adult ears occurs at a stimulus frequency of 6 kHz. These infant and adult STCs are much more similar when constructed using the absorbed power level of the stimulus and suppressor tones rather than using sound pressure level. This procedure incorporates age-related differences in forward and reverse transmission of sound power through the ear canal and middle ear. These r...

  1. Fluid Shifts: Otoacoustical Emission Changes in Response to Posture and Lower Body Negative Pressure

    Science.gov (United States)

    Melgoza, R.; Kemp, D.; Ebert, D.; Danielson, R.; Stenger, M.; Hargens, A.; Dulchavsky, S.

    2016-01-01

    INTRODUCTION: The purpose of the NASA Fluid Shifts Study is to characterize fluid distribution and compartmentalization associated with long-duration spaceflight and to correlate these findings with vision changes and other elements of the visual impairment and intracranial pressure (VIIP) syndrome. VIIP signs and symptoms, as well as postflight lumbar puncture data, suggest that elevated intracranial pressure (ICP) may be associated with spaceflight-induced cephalad fluid shifts, but this hypothesis has not been tested. Due to the invasive nature of direct measures of ICP, a noninvasive technique of monitoring ICP is desired for use during spaceflight. The phase angle and amplitude of otoacoustic emissions (OAEs) have been shown to be sensitive to posture change and ICP (1, 2), therefore use of OAEs is an attractive option. OAEs are low-level sounds produced by the sensory cells of the cochlea in response to auditory stimulation. These sounds travel peripherally from the cochlea, through the oval window, to the ear canal where they can be recorded. OAE transmission is sensitive to changes in the stiffness of the oval window, occurring as a result of changes in cochlear pressure. Increased stiffness of the oval window largely affects the transmission of sound from the cochlea at frequencies between 800 Hz and 1600 Hz. OAEs can be self-recorded in the laboratory or on the ISS using a handheld device. Our primary objectives regarding OAE measures in this experiment were to 1) validate this method during preflight testing of each crewmember (while sitting, supine and in head-down tilt position), and 2) determine if OAE measures (and presumably ICP) are responsive to lower body negative pressure and to spaceflight. METHODS: Distortion-product otoacoustic emissions (DPOAEs) and transient evoked otoacoustic emissions (TEOAEs) were recorded preflight using the Otoport Advance OAE system (Otodynamics Ltd., Hatfield, UK). Data were collected in four conditions (seated

  2. Influence of sound-conditioning on noise-induced susceptibility of distortion-product otoacoustic emissions.

    Science.gov (United States)

    Luebke, Anne E; Stagner, Barden B; Martin, Glen K; Lonsbury-Martin, Brenda L

    2015-07-01

    Cochlear damage caused by loud sounds can be attenuated by "sound-conditioning" methods. The amount of adaptation for distortion product otoacoustic emissions (DPOAEs) measured in alert rabbits previously predicted an ear's susceptibility to a subsequent noise exposure. The present study investigated if sound-conditioning influenced the robustness of such DPOAE adaptation, and if such conditioning elicited more protection by increasing the amount of DPOAE adaptation. Toward this end, rabbits were divided into two study groups: (1) experimental animals exposed to a sound-conditioning protocol, and (2) unconditioned control animals. After base-line measures, all rabbits were exposed to an overstimulation paradigm consisting of an octave band noise, and then re-assessed 3 weeks post-exposure to determine permanent changes in DPOAEs. A major result was that prior sound-conditioning protected reductions in DPOAE levels by an average of 10-15 dB. However, DPOAE adaptation decreased with sound-conditioning, so that such conditioning was no longer related to noise-induced reductions in DPOAEs. Together, these findings suggest that sound-conditioning affected neural pathways other than those that likely mediate DPOAE adaptation (e.g., medial olivocochlear efferent and/or middle-ear muscle reflexes). PMID:26233006

  3. Statistical quantification of 24-hour and monthly variabilities of spontaneous otoacoustic emission frequency in humans.

    Science.gov (United States)

    Haggerty, H S; Lusted, H S; Morton, S C

    1993-10-01

    Previous evidence has suggested a relationship between spontaneous otoacoustic emissions (SOAEs) and established, biological cycles, although detailed statistical quantifications of the suggested relationships do not exist in the literature. In an attempt to statistically quantify the purported circadian and monthly influences on this phenomenon, two experiments were undertaken. The first experiment was conducted over eight weeks, investigating 31 SOAEs recorded from eight women and two men. Time series statistical analysis examined whether daily, weekly, and/or monthly cycles characterized SOAE frequency variability. Results yielded a significant monthly cycle for the majority of SOAEs recorded from the women but for none of the SOAEs recorded from the men. These results suggest the possibility that SOAE frequency fluctuation in women may be entrained to the monthly menstrual cycle. In the second experiment, hourly SOAE frequency stability was examined over a 24-h period to ascertain the nature of the daily frequency variation as precisely as possible. Four SOAEs from two subjects were examined, and time series analysis of these data included (1) modelling the autocorrelation structure of the measurements, (2) resolving each 24-h series of measurements into cyclical components of various periodicities, and (3) testing the statistical significance of given cycles within the spectrum of each series. Findings included a significant 24-h variability of frequency for each SOAE, suggesting the possibility of a circadian influence on frequency fluctuation. Results from the two experiments provide quantitative evidence supporting a hypothetical relationship between SOAEs and established, biological cycles. PMID:8276731

  4. Masculinizing effects on otoacoustic emissions and auditory evoked potentials in women using oral contraceptives.

    Science.gov (United States)

    McFadden, D

    2000-04-01

    The otoacoustic emissions (OAEs) and auditory evoked potentials (AEPs) measured in two separate large scale studies were examined retrospectively for potential differences between those women using, and those not using, oral contraception (OC). Fourteen dependent variables were examined, all of which exhibited substantial sex differences. For 13 of those 14 dependent variables, the means for the users of OC were shifted away from the means of the non-users in the direction of the males. Specifically, for four different measures of OAE strength, for seven of eight measures of AEP latency or amplitude, and for two cognitive tests (mental rotation and water level), the means for the users of OC were located intermediate to those of the non-users of OC and the males. Few of these differences between users and non-users of OC achieved statistical significance, but the near universality of the direction of the difference suggests that oral contraceptives do produce a weak masculinizing effect on some auditory structures. These weak masculinizing effects appear to run contrary to the facts that the levels of both free testosterone and estradiol are lower in women using OC than in normal-cycling women. Past findings on auditory sex differences may have underestimated those sex differences. PMID:10748325

  5. Tinnitus is associated with reduced sound level tolerance in adolescents with normal audiograms and otoacoustic emissions

    Science.gov (United States)

    Sanchez, Tanit Ganz; Moraes, Fernanda; Casseb, Juliana; Cota, Jaci; Freire, Katya; Roberts, Larry E.

    2016-01-01

    Recent neuroscience research suggests that tinnitus may reflect synaptic loss in the cochlea that does not express in the audiogram but leads to neural changes in auditory pathways that reduce sound level tolerance (SLT). Adolescents (N = 170) completed a questionnaire addressing their prior experience with tinnitus, potentially risky listening habits, and sensitivity to ordinary sounds, followed by psychoacoustic measurements in a sound booth. Among all adolescents 54.7% reported by questionnaire that they had previously experienced tinnitus, while 28.8% heard tinnitus in the booth. Psychoacoustic properties of tinnitus measured in the sound booth corresponded with those of chronic adult tinnitus sufferers. Neither hearing thresholds (≤15 dB HL to 16 kHz) nor otoacoustic emissions discriminated between adolescents reporting or not reporting tinnitus in the sound booth, but loudness discomfort levels (a psychoacoustic measure of SLT) did so, averaging 11.3 dB lower in adolescents experiencing tinnitus in the acoustic chamber. Although risky listening habits were near universal, the teenagers experiencing tinnitus and reduced SLT tended to be more protective of their hearing. Tinnitus and reduced SLT could be early indications of a vulnerability to hidden synaptic injury that is prevalent among adolescents and expressed following exposure to high level environmental sounds. PMID:27265722

  6. Attentional modulation of the inner ear: a combined otoacoustic emission and EEG study.

    Science.gov (United States)

    Wittekindt, Anna; Kaiser, Jochen; Abel, Cornelius

    2014-07-23

    Attending to a single stimulus in a complex multisensory environment requires the ability to select relevant information while ignoring distracting input. The underlying mechanism and involved neuronal levels of this attentional gain control are still a matter of debate. Here, we investigated the influence of intermodal attention on different levels of auditory processing in humans. It is known that the activity of the cochlear amplifier can be modulated by efferent neurons of the medial olivocochlear complex. We used distortion product otoacoustic emission (DPOAE) measurements to monitor cochlear activity during an intermodal cueing paradigm. Simultaneously, central auditory processing was assessed by electroencephalography (EEG) with a steady-state paradigm targeting early cortical responses and analysis of alpha oscillations reflecting higher cognitive control of attentional modulation. We found effects of selective attention at all measured levels of the auditory processing: DPOAE levels differed significantly between periods of visual and auditory attention, showing a reduction during visual attention, but no change during auditory attention. Primary auditory cortex activity, as measured by the auditory steady-state response (ASSR), differed between conditions, with higher ASSRs during auditory than visual attention. Furthermore, the analysis of cortical oscillatory activity revealed increased alpha power over occipitoparietal and frontal regions during auditory compared with visual attention, putatively reflecting suppression of visual processing. In conclusion, this study showed both enhanced processing of attended acoustic stimuli in early sensory cortex and reduced processing of distracting input, both at higher cortical levels and at the most peripheral level of the hearing system, the cochlea. PMID:25057201

  7. The Effect of Learning Disability on Contralateral Suppression of Otoacoustic Emissions in Primary Students

    Directory of Open Access Journals (Sweden)

    Saeid Sarough Farahani

    2006-06-01

    Full Text Available Background and Aim: One of the most significant complaints of children with learning disability (LD is difficulty in understanding speech in the presence of background noise. Different studies have shown that the medial olivocochlear bundle(MOCB may play a role in hearing in noise. The MOCB function can be evaluated by the contralateral suppression of tone burst evoked otoacoustic emissions (TBEOAEs.The aim of the present study was to evaluate frequency specifications of MOCB by the contralateral suppression of TBEOAEs at 1,2,3 and 4 KHz in response to contralateral white noise in LD students. Materials and Methods: This case-control study was conducted on 34 LD students aged 7-11 years and 31 normal students matched for age.The contralateral suppression of TBEOAEs was evaluated by comparing TBEOAEs amplitudes with and without contralateral white noise. Results: In the absence of noise there was no significant difference between TBEOAEs amplitudes of two groups. In the presence of noise significant decrease was seen in TBEOAEs amplitudes at 1,2,3 and 4 KHz in both groups. In LD students the amount of this decrement at 1,2 and 4 KHz was lower than in the normal students. Conclusion: A significant diminished suppression effect at 1,2 and 4 KHz in LD students indicates that at these frequency regions MOCB function was reduced. Therefore it suggests that the assessment of MOCB by evaluating the suppression effect of TBEOAEs included in the test battery approach used in the diagnostic of LD students.

  8. Distortion product otoacoustic emissions in college music majors and nonmusic majors

    Directory of Open Access Journals (Sweden)

    Rebecca L. Warner Henning

    2016-01-01

    Full Text Available The presence and absence of distortion product otoacoustic emissions (DPOAEs as well as DPOAE amplitudes were compared between college music majors and a control group of nonmusic majors. Participants included 28 music majors and 35 nonmusic majors enrolled at a university with ages ranging from 18-25 years. DPOAEs and hearing thresholds were measured bilaterally on all the participants. DPOAE amplitudes were analyzed at the following f2 frequencies: 1,187 Hz, 1,500 Hz, 1,906 Hz, 2,531 Hz, 3,031 Hz, 3812 Hz, 4,812 Hz, and 6,031 Hz. Significantly more music majors (7/28 than nonmusic majors (0/35 exhibited absent DPOAEs for at least one frequency in at least one ear. Both groups of students reported similar histories of recreational and occupational noise exposures that were unrelated to studying music, and none of the students reported high levels of noise exposure within the previous 48 h. There were no differences in audiometric thresholds between the groups at any frequency. At DPOAE f2 frequencies from 3,031 Hz to 6,031 Hz, nonsignificantly lower amplitudes of 2-4 dB were seen in the right ears of music majors versus nonmajors, and in the right ears of music majors playing brass instruments compared to music majors playing nonbrass instruments. Given the greater prevalence of absent DPOAEs in university music majors compared to nonmusic majors, it appears that early stages of cochlear damage may be occurring in this population. Additional research, preferably longitudinal and across multiple colleges/universities, would be beneficial to more definitively determine when the music students begin to show signs of cochlear damage, and to identify whether any particular subgroups of music majors are at a greater risk of cochlear damage.

  9. Audiologic and otoacoustic emission evaluation in individuals exposed to noise and plaguecides

    Directory of Open Access Journals (Sweden)

    Morini, Renata Graziele

    2009-09-01

    Full Text Available Introduction: The noise induced hearing loss (NIHL has been studied for many years and today the specialized literature also studies the synergic action of chemicals. Objective: To research the audiologic findings and DPOAE in workers exposed to occupational noise and plaguecides and to compare them with data obtained in individuals without exposure to these harmful elements. Method: 51 individuals were evaluated (102 ears, divided into three groups. Group I was composed by 17 workers with exposure to noise and plaguecides, all with neurosensorial auditory loss; group II was composed by 17 workers with exposure to noise and plaguecides with audiometric thresholds within normality standards (up to 25 dBNA and group III by 17 healthy individuals without auditory alterations and without exposure to noise and plaguecides, control group. Results: In the audiologic anamnesis, as for groups I and II, we observed that the main auditory complaints presented by the workers were those of recruitment (29.5%, tinnitus (26.5%, allergy (23.5% and arterial hypertension (12%. The findings of the audiometry appointed that the research's individuals did not present with auditory losses in the frequencies of 500 Hz, 1 and 2 kHz, the losses occurred in the frequencies of 3 and 8 kHz. As for the distortion-product otoacoustic emissions (DPOAEs, we observed that the individuals in group III had a major incidence of responses when compared to those of groups I and II. Conclusion: The results analysis allowed us to conclude that the DPOAE test represents an important tool for follow up and prevention of NIHL.

  10. Reduced àudiogram ripple' in normally-hearing subjects with weak otoacoustic emissions.

    Science.gov (United States)

    Kapadia, S; Lutman, M E

    1999-01-01

    Correspondence between spectral patterns in otoacoustic emissions (OAE) and the fine structure of the pure-tone audiogram has often been noted, but the link is by no means clearly understood nor complete in all subjects. This paper presents part of a broader study focusing on individuals with normal hearing but anomalously weak OAEs, the primary purpose of which was to determine the reasons for the weak OAEs. Subjects were selected from an exhaustive search of some 400 ears of highly co-operative adults, and comprised a test group of subjects with normal hearing thresholds but weak OAEs, and a control group of normals from the same sample. Reported here are data on audiogram fine structure measured in the two groups of subjects. The basic finding is that the subjects with weak OAEs also exhibited significantly less audiogram fine structure than the controls, as evaluated by analysing the periodicity in the respective threshold curves as well as by identifying and quantifying individual peaks in the curves. These findings first provide further evidence of an underlying link between the fine structure of the audiogram and OAEs, as proposed by Kemp in his original work. Second, assuming that the degree of fine structure would be largely unaffected by minor middle ear alterations, our findings suggest that predominantly cochlear rather than middle ear factors are responsible for the low levels of OAEs in the normal subjects of our test group. Finally, the results presented suggest that, like OAEs, audiogram fine structure measurements provide information on the auditory system that is not available in the conventional pure-tone audiogram. PMID:10548372

  11. Abnormal fast fluctuations of electrocochleography and otoacoustic emissions in Menière's disease.

    Science.gov (United States)

    Gerenton, Grégory; Giraudet, Fabrice; Djennaoui, Idir; Pavier, Yoann; Gilain, Laurent; Mom, Thierry; Avan, Paul

    2015-09-01

    The responses of cochlear hair cells to sound stimuli depend on the resting position of their stereocilia bundles, which is sensitive to the chemical and mechanical environment. Cochlear hydrops, a hallmark of Menière's disease (MD), which is likely to come with disruption of this environment, results in hearing symptoms and electrophysiological signs, such as excessive changes in the cochlear summating potential (SP) and in the postural shifts of distortion-product otoacoustic emissions (DPOAEs). Here, SP from the basal part of the cochlea and DPOAEs from the apical part of the cochlea were recorded concomitantly in 73 patients with a definite MD, near an attack (n = 40) or between attacks with no clinical symptoms (n = 33), to compare their sensitivities to posture and evaluate their stability. The phase of the 2f1-f2 DPOAEs was monitored during body tilt, with stimuli f1 = 1 kHz and f2 = 1.2 kHz at 72 dB SPL. Extratympanic electrocochleography was performed in response to 95-dBnHL clicks. The normal limits of the DPOAE phase shift with body tilt, [-18°, +38°], and of the SP to action-potential (AP) ratio, cochlear responses from one data sample to the next. They emphasize how hydrops hinders normal hair-cell operation and may generate fast fluctuations in inner-ear functioning. If these fluctuations also occur on shorter time scales, it might explain the imperfect diagnostic sensitivity of SP and DPOAE tests, as averaging procedures would tend to level out transient fluctuations characteristic of hydrops. PMID:26232527

  12. Mechanical tuning of the moth ear: distortion-product otoacoustic emissions and tympanal vibrations.

    Science.gov (United States)

    Mora, Emanuel C; Cobo-Cuan, Ariadna; Macías-Escrivá, Frank; Pérez, Martha; Nowotny, Manuela; Kössl, Manfred

    2013-10-15

    The mechanical tuning of the ear in the moth Empyreuma pugione was investigated by distortion-product otoacoustic emissions (DPOAE) and laser Doppler vibrometry (LDV). DPOAE audiograms were assessed using a novel protocol that may be advantageous for non-invasive auditory studies in insects. To evoke DPOAE, two-tone stimuli within frequency and level ranges that generated a large matrix of values (960 frequency-level combinations) were used to examine the acoustic space in which the moth tympanum shows its best mechanical and acoustical responses. The DPOAE tuning curve derived from the response matrix resembles that obtained previously by electrophysiology, and is V-shaped and tuned to frequencies between 25 and 45 kHz with low Q10dB values of 1.21±0.26. In addition, while using a comparable stimulation regime, mechanical distortion in the displacement of the moth's tympanal membrane at the stigma was recorded with a laser Doppler vibrometer. The corresponding mechanical vibration audiograms were compared with DPOAE audiograms. Both types of audiograms have comparable shape, but most of the mechanical response fields are shifted towards lower frequencies. We showed for the first time in moths that DPOAE have a pronounced analogy in the vibration of the tympanic membrane where they may originate. Our work supports previous studies that point to the stigma (and the internally associated transduction machinery) as an important place of sound amplification in the moth ear, but also suggests a complex mechanical role for the rest of the transparent zone. PMID:23868848

  13. Distortion product otoacoustic emissions in college music majors and nonmusic majors.

    Science.gov (United States)

    Henning, Rebecca L Warner; Bobholz, Kate

    2016-01-01

    The presence and absence of distortion product otoacoustic emissions (DPOAEs) as well as DPOAE amplitudes were compared between college music majors and a control group of nonmusic majors. Participants included 28 music majors and 35 nonmusic majors enrolled at a university with ages ranging from 18-25 years. DPOAEs and hearing thresholds were measured bilaterally on all the participants. DPOAE amplitudes were analyzed at the following f2 frequencies: 1,187 Hz, 1,500 Hz, 1,906 Hz, 2,531 Hz, 3,031 Hz, 3812 Hz, 4,812 Hz, and 6,031 Hz. Significantly more music majors (7/28) than nonmusic majors (0/35) exhibited absent DPOAEs for at least one frequency in at least one ear. Both groups of students reported similar histories of recreational and occupational noise exposures that were unrelated to studying music, and none of the students reported high levels of noise exposure within the previous 48 h. There were no differences in audiometric thresholds between the groups at any frequency. At DPOAE f2 frequencies from 3,031 Hz to 6,031 Hz, nonsignificantly lower amplitudes of 2-4 dB were seen in the right ears of music majors versus nonmajors, and in the right ears of music majors playing brass instruments compared to music majors playing nonbrass instruments. Given the greater prevalence of absent DPOAEs in university music majors compared to nonmusic majors, it appears that early stages of cochlear damage may be occurring in this population. Additional research, preferably longitudinal and across multiple colleges/universities, would be beneficial to more definitively determine when the music students begin to show signs of cochlear damage, and to identify whether any particular subgroups of music majors are at a greater risk of cochlear damage. PMID:26780957

  14. Distortion product otoacoustic emissions in college music majors and nonmusic majors

    Science.gov (United States)

    Henning, Rebecca L. Warner; Bobholz, Kate

    2016-01-01

    The presence and absence of distortion product otoacoustic emissions (DPOAEs) as well as DPOAE amplitudes were compared between college music majors and a control group of nonmusic majors. Participants included 28 music majors and 35 nonmusic majors enrolled at a university with ages ranging from 18-25 years. DPOAEs and hearing thresholds were measured bilaterally on all the participants. DPOAE amplitudes were analyzed at the following f2 frequencies: 1,187 Hz, 1,500 Hz, 1,906 Hz, 2,531 Hz, 3,031 Hz, 3812 Hz, 4,812 Hz, and 6,031 Hz. Significantly more music majors (7/28) than nonmusic majors (0/35) exhibited absent DPOAEs for at least one frequency in at least one ear. Both groups of students reported similar histories of recreational and occupational noise exposures that were unrelated to studying music, and none of the students reported high levels of noise exposure within the previous 48 h. There were no differences in audiometric thresholds between the groups at any frequency. At DPOAE f2 frequencies from 3,031 Hz to 6,031 Hz, nonsignificantly lower amplitudes of 2-4 dB were seen in the right ears of music majors versus nonmajors, and in the right ears of music majors playing brass instruments compared to music majors playing nonbrass instruments. Given the greater prevalence of absent DPOAEs in university music majors compared to nonmusic majors, it appears that early stages of cochlear damage may be occurring in this population. Additional research, preferably longitudinal and across multiple colleges/universities, would be beneficial to more definitively determine when the music students begin to show signs of cochlear damage, and to identify whether any particular subgroups of music majors are at a greater risk of cochlear damage. PMID:26780957

  15. Contralateral acoustic suppression of transient evoked otoacoustic emissions: Activation of the medial olivocochlear system

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    Komazec Zoran

    2003-01-01

    Full Text Available Medial olivocochlear pathway represents the final part of efferent acoustic pathway which comes from the superior olivary complex ending at outer hair cells. Activation of medial olivocochlear system (MOCS alters the cochlear output decreasing the travelling wave within cochlea. Stimulation of MOCS provides protection against moderate levels of noise, encoding noise signals as well as selecting hearing attention. Activation of MOCS can be performed using contralateral acoustic stimulation. The principal result of presentation of contralateral acoustic stimulation during screening of transient evoked otoacoustic emission (TEOAE is an attenuation of the TEOAE amplitude. Thirty-eight ears were examined in this study: twenty-eight ears from 14 normal-hearing adults and 10 patients with unilateral deafness. Healthy subjects were exposed to contralateral broad-band noise of various intensities (40, 30, 20 and 10 dB SL, as well as 30 dB SL pure tone stimulation (1 kHz and 4 kHz. A decrease of TEOAE amplitudes during contralateral stimulation with 40 and 30 dB SL broad-band noise and pure tones was established. This effect was a result of MOCS activation. A greater intensity of contralateral stimulation evoked greater decrease of TEOAE amplitude; stimulation with broad-band noise caused greater attenuation than with pure tone stimulation. Contralateral stimulation of deaf ears in the group with unilateral deafness was also performed. Statistically significant difference between TEOAE amplitude before and during contralateral stimulation was not established. This circumstance explains that activation of MOCS and consequent reduction of outer hair cells motility is very possibly caused by contralateral acoustic stimulation. Apart from studying physiological significance of efferent auditory system, results of this and similar studies can be used for production of hearing aids improving speech discrimination in noisy environment.

  16. Theory of forward and reverse middle-ear transmission applied to otoacoustic emissions in infant and adult ears

    OpenAIRE

    Keefe, Douglas H.; Abdala, Carolina

    2007-01-01

    The purpose of this study is to understand why otoacoustic emission (OAE) levels are higher in normal-hearing human infants relative to adults. In a previous study, distortion product (DP) OAE input/output (I/O) functions were shown to differ at f2=6 kHz in adults compared to infants through 6 months of age. These DPOAE I/O functions were used to noninvasively assess immaturities in forward/reverse transmission through the ear canal and middle ear [Abdala, C., and Keefe, D. H., (2006). J. Aco...

  17. Recovery of Otoacoustic Emission Function in Luetic Endolymphatic Hydrops: A Possible Measure of Improvement in Cochlear Function

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    Robert H. Chun

    2009-01-01

    Full Text Available Syphilis is a preventable and curable multi-organ disease caused by Treponema pallidum that may also affect the inner ear. First reported in 1887 by Adam Politzer, luetic endolymphatic hydrops (LEH is a treatable complication of syphilis which causes a potentially reversible sensorineural hearing loss. Symptoms of LEH include fluctuating hearing loss (often low frequency, tinnitus, and vertigo. Though audiometric parameters have been examined in patients with otosyphilis, few studies have examined the use of otoacoustic emissions (OAEs as a tool to measure improvement in cochlear function. Here we report an improvement in hearing loss, speech discrimination, and OAEs following treatment of LEH.

  18. Distortion-product otoacoustic emission reflection-component delays and cochlear tuning: estimates from across the human lifespan.

    Science.gov (United States)

    Abdala, Carolina; Guérit, François; Luo, Ping; Shera, Christopher A

    2014-04-01

    A consistent relationship between reflection-emission delay and cochlear tuning has been demonstrated in a variety of mammalian species, as predicted by filter theory and models of otoacoustic emission (OAE) generation. As a step toward the goal of studying cochlear tuning throughout the human lifespan, this paper exploits the relationship and explores two strategies for estimating delay trends-energy weighting and peak picking-both of which emphasize data at the peaks of the magnitude fine structure. Distortion product otoacoustic emissions (DPOAEs) at 2f1-f2 were recorded, and their reflection components were extracted in 184 subjects ranging in age from prematurely born neonates to elderly adults. DPOAEs were measured from 0.5-4 kHz in all age groups and extended to 8 kHz in young adults. Delay trends were effectively estimated using either energy weighting or peak picking, with the former method yielding slightly shorter delays and the latter somewhat smaller confidence intervals. Delay and tuning estimates from young adults roughly match those obtained from SFOAEs. Although the match is imperfect, reflection-component delays showed the expected bend (apical-basal transition) near 1 kHz, consistent with a break in cochlear scaling. Consistent with other measures of tuning, the term newborn group showed the longest delays and sharpest tuning over much of the frequency range. PMID:25234993

  19. Comparing Distortion Product Otoacoustic Emissions to Intracochlear Distortion Products Inferred from a Noninvasive Assay.

    Science.gov (United States)

    Martin, Glen K; Stagner, Barden B; Dong, Wei; Lonsbury-Martin, Brenda L

    2016-08-01

    The behavior of intracochlear distortion products (iDPs) was inferred by interacting a probe tone (f3) with the iDP of interest to produce a "secondary" distortion product otoacoustic emission termed DPOAE(2ry). Measures of the DPOAE(2ry) were then used to deduce the properties of the iDP. This approach was used in alert rabbits and anesthetized gerbils to compare ear-canal 2f1-f2 and 2f2-f1 DPOAE f2/f1 ratio functions, level/phase (L/P) maps, and interference-response areas (IRAs) to their simultaneously collected DPOAE(2ry) counterparts. These same measures were also collected in a human volunteer to demonstrate similarities with their laboratory animal counterparts and their potential applicability to humans. Results showed that DPOAEs and inferred iDPs evidenced distinct behaviors and properties. That is, DPOAE ratio functions elicited by low-level primaries peaked around an f2/f1 = 1.21 or 1.25, depending on species, while the corresponding inferred iDP ratio functions peaked at f2/f1 ratios of ~1. Additionally, L/P maps showed rapid phase variation with DPOAE frequency (fdp) for the narrow-ratio 2f1-f2 and all 2f2-f1 DPOAEs, while the corresponding DPOAE(2ry) measures evidenced relatively constant phases. Common features of narrow-ratio DPOAE IRAs, such as large enhancements for interference tones (ITs) presented above f2, were not present in DPOAE(2ry) IRAs. Finally, based on prior experiments in gerbils, the behavior of the iDP directly measured in intracochlear pressure was compared to the iDP inferred from the DPOAE(2ry) and found to be similar. Together, these findings are consistent with the notion that under certain conditions, ear-canal DPOAEs provide poor representations of iDPs and thus support a "beamforming" hypothesis. According to this concept, distributed emission components directed toward the ear canal from the f2 and basal to f2 regions can be of differing phases and thus cancel, while these same components directed toward fdp add in

  20. The Effect of Acute Otitis Media on Transient Otoacoustic Emissions A Clinical Guide to Successful Treatment Course

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    A. Bayat

    Full Text Available Introduction & Objective: Acute otitis media (AOM is the most common causes of acquired hearing loss in children with increasing incidence. In young children the diagnosis is restricted to otoscopy and tympanometry whereas evaluation of the auditory function is impossible due to noncompliance during pure tone audiometry. For this purpose, measurement of otoacoustic emissions, especially transient evoked ones (TEOAEs, can be applied. The aim of this study was to evaluate the effect of AOM on TEOAEs in young children before and after treatment course.Material & Methods: In an analytic, cross-sectional design, 42 young children with AOM, both sexes, aged 2 to 4.5 years were evaluated through tympanometry and transient otoacoustic emissions (TEOAEs. TEOAEs signal to noise ratio (SNR and reproducibility of AOM patients were compared before, two weeks and six weeks after the treatment course. Then AOM responses were compared with an age-matched control group. The results were analyzed using SPSS 16.Results: Our findings revealed that TEOAE parameters in AOM subjects were the most affected on highest frequencies. Significant changes of TEOAE parameters were found 2 weeks after the treatment with further improvement 6 weeks after the treatment course (P 0.05.Conclusion: The results of this study suggest that there was an improvement in TEOAE SNR and band reproducibility in serial TEOAEs measurements. Thus,application of TEOAEs is a beneficial method to follow up medical treatment in young children with AOM. (Sci J Hamadan Univ Med Sci 2011;18(3:17-21

  1. Study on suppression of otoacoustic emissions: lateral domain Estudo da supressão da amplitude das emissões otoacústicas: dominância lateral

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    Jerusa Roberta Massola de Oliveira

    2011-10-01

    Full Text Available A pon stimulation by contralateral, ipsilateral or bilateral noise, the medial olivocochlear efferent tract changes the amplitude of otoacoustic emissions relative to the tested ear, reducing or removing it; this resulted in a reduction/suppression effect of otoacoustic emissions. Differences in patterns of elimination/reduction of otoacoustic emissions between ears have been documented worldwide; there are, however, no Brazilian studies investigating the effect of lateral dominance. AIMS: To compare the effect of the presence of deletion/reduction of otoacoustic emissions and their amplitude relative to lateral dominance in normal hearing adults. METHODS: A clinical and experimental study. The sample comprised 75 individuals. The methodology was conventional - linear click intensity of 60 dB SPL; white noise was contralateral stimulation at 60 dB SPL. DESCRIPTION OF RESULTS: There were no statistically significant differences between right and left ear results, in terms of asymmetry of the degree of otoacoustic emissions and the presence of suppression/reduction. CONCLUSION: There is no lateral dominance in the degree of otoacoustic emissions in the presence of suppression/reduction in the study population.O trato olivococlear medial eferente, ao ser estimulado por ruído contralateral, ipsilateral ou bilateralmente em relação à orelha testada, altera a amplitude da resposta das emissões otoacústicas, reduzindo-a ou suprimindo-a, resultando no efeito de redução/supressão das emissões otoacústicas. Diferenças nos padrões de supressão/redução das emissões otoacústicas entre as orelhas foram documentadas internacionalmente, porém não há trabalhos nacionais que investigaram a dominância lateral do efeito. OBJETIVO: Comparar a presença efeito de supressão/redução das emissões otoacústicas e sua amplitude no que se refere à dominância lateral em indivíduos adultos audiologicamente normais. MATERIAL E MÉTODO: Clínico e

  2. Efeito da acupuntura sobre as emissões otoacústicas de pacientes com zumbido Impact of acupuncture on otoacoustic emissions in patients with tinnitus

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    Renata Frasson de Azevedo

    2007-10-01

    Full Text Available O tratamento do zumbido continua a ser um desafio da atualidade. Na medicina tradicional chinesa, a acupuntura é recomendada para o alívio do zumbido, apesar de faltarem provas cientificas nesta área. OBJETIVO: Verificar o efeito da acupuntura sobre a função coclear de indivíduos com zumbido através do uso das emissões otoacústicas. CASUÍSTICA E MÉTODO: Foi realizado um estudo clínico-prospectivo, no qual foram avaliados 38 pacientes do ambulatório de zumbido. Os pacientes foram avaliados por meio de emissões otoacústicas transitórias e pela medida da supressão das emissões otoacústicas transitórias. Essa avaliação foi realizada antes e após a aplicação de acupuntura em um ponto na região têmporo-parietal, correspondente à área cócleo-vestibular (no grupo intervenção 1 n=19 e em um ponto 3cm acima dessa região (para o grupo intervenção 2 n=19. RESULTADOS: Os resultados mostraram uma diferença estatisticamente significante na amplitude das emissões otoacústicas antes e após a aplicação da acupuntura para o grupo intervenção 1. Não foram observadas diferenças para o grupo intervenção 2. CONCLUSÃO: Os resultados sugerem que houve um efeito da acupuntura sobre as emissões otoacústicas dos pacientes com zumbido.The treatment of tinnitus is still a challenge. Acupuncture is recommended for the relief of tinnitus in traditional Chinese Medicine, although scientific evidence is lacking. AIM: The aim of this study was to assess the effect of acupuncture on the cochlear function in patients with tinnitus by analyzing otoacoustic emissions. METHODS: Thirty eight patients with tinnitus were included in the prospective clinical study. Measures of transitory otoacoustic emissions and suppression of otoacoustic emissions were obtained from all subjects before and after acupuncture. Patients were assigned to one of two groups: intervention group 1 (n=19, in which needle acupuncture was applied at the

  3. Absent otoacoustic emissions predict otitis media in young Aboriginal children: A birth cohort study in Aboriginal and non-Aboriginal children in an arid zone of Western Australia

    OpenAIRE

    Stokes Annette; Finucane Janine; Elsbury Dimity; Jacoby Peter; Weeks Sharon; Lehmann Deborah; Monck Ruth; Coates Harvey

    2008-01-01

    Abstract Background Otitis media (OM) is the most common paediatric illness for which antibiotics are prescribed. In Australian Aboriginal children OM is frequently asymptomatic and starts at a younger age, is more common and more likely to result in hearing loss than in non-Aboriginal children. Absent transient evoked otoacoustic emissions (TEOAEs) may predict subsequent risk of OM. Methods 100 Aboriginal and 180 non-Aboriginal children in a semi-arid zone of Western Australia were followed ...

  4. Supressão contralateral das emissões otoacústicas nos indivíduos com zumbido Contralateral suppression of otoacoustic emission in patients with tinnitus

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    Mariana Lopes Fávero

    2006-04-01

    Full Text Available INTRODUÇÃO: A função do trato olivococlear medial é estudada pela supressão das emissões otoacústicas com o uso de uma estimulação contralateral e sofre influência da lateralidade do sistema nervoso central, não apresentando respostas iguais entre as orelhas. Uma disfunção neste trato pode implicar na geração do zumbido, porém isto ainda não foi confirmado. OBJETIVO: Estudar a supressão das emissões otoacústicas por produto de distorção em indivíduos com zumbido. MATERIAL E MÉTODO: Estudo caso-controle com 44 pessoas com zumbido, matriculadas no Ambulatório de Zumbido da Divisão de Clínica Otorrinolaringológica do Hospital das Clínicas da Universidade de São Paulo e 44 voluntários submetidos à emissão otoacústica por produto de distorção com e sem estimulação contralateral. Comparou-se os resultados das orelhas direita dos dois grupos. RESULTADOS: Houve associação entre zumbido e ausência de supressão em todas as freqüências estudadas (OR>2,1. CONCLUSÕES: Houve uma correlação entre menor efetividade do trato olivococlear medial e a presença de zumbido.INTRODUCTION: The medial olivocochlear bundle effect is studied through the suppression of otoacoustic emissions and seems to be influenced by the laterality of the central nervous system, presenting no symmetry between right and left ear. A dysfunction of this bundle may be involved in the generation of tinnitus, although this fact was not confirmed. OBJECTIVES: Study the suppression of distortion product otoacoustic emissions in tinnitus patients. MATERIAL AND METHOD: A case-controlled study involving 44 tinnitus patients from the Tinnitus Group of the ENT Department of the University of São Paulo Medical School and 44 controls who underwent distortion product otoacoustic emissions testing with and without contralateral noise. Only the results from the right ears from both groups were compared. RESULTS: There was a relationship between the

  5. Time-frequency analysis of stimulus frequency otoacoustic emissions and their changes with efferent stimulation in guinea pigs

    Science.gov (United States)

    Berezina-Greene, Maria A.; Guinan, John J.

    2015-12-01

    To aid in understanding their origin, stimulus frequency otoacoustic emissions (SFOAEs) were measured at a series of tone frequencies using the suppression method, both with and without stimulation of medial olivocochlear (MOC) efferents, in anesthetized guinea pigs. Time-frequency analysis showed SFOAE energy peaks in 1-3 delay components throughout the measured frequency range (0.5-12 kHz). One component's delay usually coincided with the phase-gradient delay. When multiple delay components were present, they were usually near SFOAE dips. Below 2 kHz, SFOAE delays were shorter than predicted from mechanical measurements. With MOC stimulation, SFOAE amplitude was decreased at most frequencies, but was sometimes enhanced, and all SFOAE delay components were affected. The MOC effects and an analysis of model data suggest that the multiple SFOAE delay components arise at the edges of the traveling-wave peak, not far basal of the peak. Comparisons with published guinea-pig neural data suggest that the short latencies of low-frequency SFOAEs may arise from coherent reflection from an organ-of-Corti motion that has a shorter group delay than the traveling wave.

  6. Lack of contralateral suppression in transient-evoked otoacoustic emissions in multiple chemical sensitivity: a clinical correlation study

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    Alessandro Micarelli

    2016-01-01

    Full Text Available Multiple chemical sensitivity (MCS is a chronic disorder characterized by a variety of symptoms associated with the exposure to chemicals at a concentration below the toxic level. Previous studies have demonstrated peculiar responses in brain activity in these patients with respect to sensory stimuli while the association between chemical sensitivity and other environmental intolerances such as noise sensitivity has been questioned by researchers. In this study, a cohort of 18 MCS patients underwent transient-evoked otoacoustic emission (TEOAE testing with and without contralateral suppression to evaluate the functionality of the medial olivocochlear (MOC reflex involved in speech-in-noise sensitivity. Results were compared with an age- and gender-matched control group (n = 20 and correlation analysis with disease onset and quick environmental exposure sensitivity inventory (qEESI symptom severity scale was performed. Subjects affected by MCS showed statistically significant impairment of MOC reflex, and the onset of the disease and several symptom subscales showed to be correlated to such reduction in some of the frequencies tested. These data suggest that alterations of MOC reflex could be part of the complex features of this disease although more studies are needed to further explore auditory perception disorders in environmental intolerances.

  7. Lack of contralateral suppression in transient-evoked otoacoustic emissions in multiple chemical sensitivity: a clinical correlation study.

    Science.gov (United States)

    Micarelli, Alessandro; Viziano, Andrea; Genovesi, Giuseppe; Bruno, Ernesto; Ottaviani, Fabrizio; Alessandrini, Marco

    2016-01-01

    Multiple chemical sensitivity (MCS) is a chronic disorder characterized by a variety of symptoms associated with the exposure to chemicals at a concentration below the toxic level. Previous studies have demonstrated peculiar responses in brain activity in these patients with respect to sensory stimuli while the association between chemical sensitivity and other environmental intolerances such as noise sensitivity has been questioned by researchers. In this study, a cohort of 18 MCS patients underwent transient-evoked otoacoustic emission (TEOAE) testing with and without contralateral suppression to evaluate the functionality of the medial olivocochlear (MOC) reflex involved in speech-in-noise sensitivity. Results were compared with an age- and gender-matched control group (n = 20) and correlation analysis with disease onset and quick environmental exposure sensitivity inventory (qEESI) symptom severity scale was performed. Subjects affected by MCS showed statistically significant impairment of MOC reflex, and the onset of the disease and several symptom subscales showed to be correlated to such reduction in some of the frequencies tested. These data suggest that alterations of MOC reflex could be part of the complex features of this disease although more studies are needed to further explore auditory perception disorders in environmental intolerances. PMID:27157687

  8. Investigation of potential effects of cellular phones on human auditory function by means of distortion product otoacoustic emissions

    Science.gov (United States)

    Janssen, Thomas; Boege, Paul; von Mikusch-Buchberg, Jutta; Raczek, Johannes

    2005-03-01

    Outer hair cells (OHC) are thought to act like piezoelectric transducers that amplify low sounds and hence enable the ear's exquisite sensitivity. Distortion product otoacoustic emissions (DPOAE) reflect OHC function. The present study investigated potential effects of electromagnetic fields (EMF) of GSM (Global System for Mobile Communication) cellular phones on OHCs by means of DPOAEs. DPOAE measurements were performed during exposure, i.e., between consecutive GSM signal pulses, and during sham exposure (no EMF) in 28 normally hearing subjects at tone frequencies around 4 kHz. For a reliable DPOAE measurement, a 900-MHz GSM-like signal was used where transmission pause was increased from 4.034 ms (GSM standard) to 24.204 ms. Peak transmitter power was set to 20 W, corresponding to a specific absorption rate (SAR) of 0.1 W/kg. No significant change in the DPOAE level in response to the EMF exposure was found. However, when undesired side effects on DPOAEs were compensated, in some subjects an extremely small EMF-exposure-correlated change in the DPOAE level (physiologically irrelevant. .

  9. Comparison between distortion product otoacoustic emissions and nerve fiber responses from the basilar papilla of the frog

    Science.gov (United States)

    Meenderink, Sebastiaan W. F.; van Dijk, Pim; Narins, Peter M.

    2005-05-01

    The basilar papilla (BP) is one of the three end organs in the frog inner ear that is sensitive to airborne sound. Its anatomy and physiology are unique among all classes of vertebrates. Essentially, the BP functions as a single auditory filter presumably arising from a mechanically-tuned mechanism. As such, both neural and distortion product otoacoustic emission (DPOAE) tuning may reflect a single mechanical filtering mechanism. Using the Duffing oscillator as a simple model for both neural and DPOAE tuning from the BP, two predictions can be made: [1] the characteristic frequency (CF) of neural tuning and the best frequency (BF) of DPOAE tuning will coincide and [2] the neural tuning curve and DPOAE-audiogram have a similar shape when the neural tuning curve is scaled by a factor of 4 along the y-axis. We recorded both neural tuning curves and DPOAE-audiograms from the BP of the leopard frog. These recordings show good agreement with the model predictions when the stimulus tones are related by relatively small stimulus frequency ratios. For larger stimulus frequency ratios, DPOAE recordings clearly deviate from model predictions. These differences are most likely caused by the oversimplified representation of the frog BP by the model. .

  10. A longitudinal study of distortion product otoacoustic emission ipsilateral suppression and input/output characteristics in human neonates

    Science.gov (United States)

    Abdala, Carolina

    2003-12-01

    Past work has shown that distortion product otoacoustic emission (DPOAE) (2f1-f2) ipsilateral suppression and input/output (I/O) characteristics are not adult-like in prematurely born neonates [Abdala, J. Acoust. Soc. Am. 110, 1465-1476 (2001)]. These age differences are most pronounced at f2=6000 Hz and have been interpreted to indicate a subtle immaturity in human cochlear function prior to term birth. It is still not clear, however, whether term-born neonates are completely adult-like in cochlear function. To study this question, DPOAE suppression and I/O functions for f2=6000 Hz were measured in a group of prematurely born neonates at weekly intervals over a period of 7-8-weeks, a group of normal-hearing adults, and during a one-time test session in a group of term-born neonates. Results show that there was no significant change in suppression tuning, suppression growth, and various I/O characteristics across test session for premature neonates, but there was an age-group effect; even once prematurely born neonates reached the equivalence of term-like status (38-40-weeks postconceptional weeks), they continued to show narrower suppression tuning than adults, shallower suppression growth for low-frequency side suppressor tones, and an elevated amplitude saturation plateau on the I/O function. Term-born neonates showed DPOAE results that were comparable to those measured from premature neonates and unlike adult findings. These results suggest that a subtle immaturity in cochlear function persists into the postnatal period.

  11. Evidence for the distortion product frequency place as a source of distribution product otoacoustic emission (DPOAE) fine structure in humans. I. Fine structure and higher-order DPOAE as a function of the frequency ratio f2/f1

    NARCIS (Netherlands)

    Mauermann, M; Uppenkamp, S; van Hengel, PWJ; Kollmeier, B

    1999-01-01

    Critical experiments were performed in order to validate the two-source hypothesis of distortion product otoacoustic emissions (DPOAE) generation. Measurements of the spectral fine structure of DPOAE in response to stimulation with two sinusoids have been:performed with normal-hearing subjects. The

  12. Emissões otoacústicas por produtos de distorção em ovinos normais e após indução de hiperinsulinemia Distortion product otoacoustic emissions in sheep before and after hyperinsulinemia induction

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    Francisco Carlos Zuma e Maia

    2008-04-01

    Full Text Available As emissões otoacústicas transientes evocadas e as emissões otoacústicas por produtos de distorção vêm assumindo importância significativa na identificação de alterações cocleares. OBJETIVO: Através da monitorização das emissões otoacústicas, registrar os limiares dos produtos de distorção em condições normais e na presença de modificações eletrofisiológicas nas células ciliadas externas cocleares de ovelhas após a indução de hiperinsulinemia aguda. MATERIAL E MÉTODO: Estudo experimental com sete ovelhas no grupo-controle e sete no grupo-estudo. Os níveis de insulina e glicose foram verificados simultaneamente ao registro das emissões otoacústicas por produtos de distorção de 10 em 10 minutos, até o tempo de 90 minutos. O grupo-controle recebeu soro fisiológico, e o grupo-estudo, injeção em bolo de 0,1 U/kg de insulina humana regular. RESULTADOS: Houve diminuição significante nos limiares dos produtos de distorção no grupo-estudo em relação ao grupo-controle nas freqüências acima de 1.500 Hz e após o tempo de 60 minutos (P Transient evoked otoacoustic emissions and distortion product otoacoustic emissions have gained significant importance in the identification of cochlear alterations. AIM: To record distortion product thresholds through the monitoring of otoacoustic emissions in normal conditions and in the presence of electrophysiologic changes in cochlear outer hair cells in sheep after hyperinsulinemia induction. MATERIAL AND METHODS: Experimental study, with seven sheep in the control group and seven in the study group. Insulin and glucose concentrations were measured simultaneously for the recording of distortion product otoacoustic emission every 10 minutes, all the way to 90 minutes. The control group received saline solution, and the study group received a bolus injection of 0.1 U/kg of regular human insulin. RESULTS: There was a significant reduction in distortion product thresholds in

  13. Portadores de vitiligo: estudo das emissões otoacústicas e efeito de supressão A study on otoacoustic emissions and supression effects in patients with vitiligo

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    Rosanna Mariangela Giaffredo Angrisani

    2009-02-01

    Full Text Available Vitiligo é uma doença cutânea, caracterizada pela ausência da melanina, por destruição de melanócitos. OBJETIVO: Verificar a ocorrência de alteração auditiva em indivíduos com vitiligo. MÉTODO: Avaliação audiológica, pesquisa das emissões otoacústicas evocadas transientes e do efeito de supressão em estudo prospectivo de 24 pacientes com vitiligo. A faixa etária variou de 15 a 45 anos. RESULTADOS: 21 pacientes (87.5% apresentaram audiometria normal; dois apresentaram perda auditiva unilateral em freqüências altas e um apresentou perda coclear de grau moderado à esquerda. Destes 21 sujeitos, 66,7% tiveram ausência de emissões, sugerindo disfunção coclear. As emissões estiveram presentes em todas as bandas de freqüência em apenas 7 pacientes (29,2% e ausentes em 17 (70,8%, com maior ocorrência de falha no sexo masculino, na orelha direita. Na pesquisa da supressão, seis indivíduos falharam, todos do sexo feminino, sendo a orelha esquerda a mais afetada. CONCLUSÃO: Pela análise das emissões otoacústicas verificou-se que os portadores de vitiligo possuem maior predisposição à disfunção coclear, com maior ocorrência no sexo masculino na orelha direita. Quanto ao efeito de supressão, houve maior alteração no sistema eferente em mulheres, com maior ausência à esquerda. As alterações auditivas não diferiram quanto à idade, tipo de vitiligo e tempo de evolução da doença.Vitiligo is a skin disease characterized by absence of melanin due to melanocytes destruction. AIM: to study the incidence of hearing alterations in patients with vitiligo. METHOD: prospective audiological evaluation, transient-evoked otoacoustic emission recordings and study the effects of suppression in 24 patients with vitiligo. Their ages ranged from 15 to 45 years. RESULTS: 21 patients (87.5% had normal audiometry; 2 had unilateral hearing loss in the high frequencies and 1 had cochlear moderate hearing loss in the left ear. Of

  14. Absent otoacoustic emissions predict otitis media in young Aboriginal children: A birth cohort study in Aboriginal and non-Aboriginal children in an arid zone of Western Australia

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    Stokes Annette

    2008-08-01

    Full Text Available Abstract Background Otitis media (OM is the most common paediatric illness for which antibiotics are prescribed. In Australian Aboriginal children OM is frequently asymptomatic and starts at a younger age, is more common and more likely to result in hearing loss than in non-Aboriginal children. Absent transient evoked otoacoustic emissions (TEOAEs may predict subsequent risk of OM. Methods 100 Aboriginal and 180 non-Aboriginal children in a semi-arid zone of Western Australia were followed regularly from birth to age 2 years. Tympanometry was conducted at routine field follow-up from age 3 months. Routine clinical examination by an ENT specialist was to be done 3 times and hearing assessment by an audiologist twice. TEOAEs were measured at ages Results At routine ENT specialist clinics, OM was detected in 55% of 184 examinations in Aboriginal children and 26% of 392 examinations in non-Aboriginal children; peak prevalence was 72% at age 5–9 months in Aboriginal children and 40% at 10–14 months in non-Aboriginal children. Moderate-severe hearing loss was present in 32% of 47 Aboriginal children and 7% of 120 non-Aboriginal children aged 12 months or more. TEOAE responses were present in 90% (46/51 of Aboriginal children and 99% (120/121 of non-Aboriginal children aged Overall prevalence of type B tympanograms at field follow-up was 50% (n = 78 in Aboriginal children and 20% (n = 95 in non-Aboriginal children. Conclusion The burden of middle ear disease is high in all children, but particularly in Aboriginal children, one-third of whom suffer from moderate-severe hearing loss. In view of the frequently silent nature of OM, every opportunity must be taken to screen for OM. Measurement of TEOAEs at age 1–2 months to identify children at risk of developing OM should be evaluated in a routine health service setting.

  15. Otoacoustic Estimates of Cochlear Tuning: Testing Predictions in Macaque

    Science.gov (United States)

    Shera, Christopher A.; Bergevin, Christopher; Kalluri, Radha; Mc Laughlin, Myles; Michelet, Pascal; van der Heijden, Marcel; Joris, Philip X.

    2011-11-01

    Otoacoustic estimates of cochlear frequency selectivity suggest substantially sharper tuning in humans. However, the logic and methodology underlying these estimates remain untested by direct measurements in primates. We report measurements of frequency tuning in macaque monkeys, Old-World primates phylogenetically closer to humans than the small laboratory animals often taken as models of human hearing (e.g., cats, guinea pigs, and chinchillas). We find that measurements of tuning obtained directly from individual nerve fibers and indirectly using otoacoustic emissions both indicate that peripheral frequency selectivity in macaques is significantly sharper than in small laboratory animals, matching that inferred for humans at high frequencies. Our results validate the use of otoacoustic emissions for noninvasive measurement of cochlear tuning and corroborate the finding of sharper tuning in humans.

  16. Medidas da latência das emissões otoacústicas - produto de distorção em neonatos Measures of distortion product otoacoustic emissions latency in neonates

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    Renata Frasson de Azevedo

    2003-10-01

    Full Text Available A latência do produto de distorção das emissões otoacústicas é definido como o tempo que o estimulo acústico leva para alcançar o local gerador da emissão otoacústica na cóclea e retornar ao meato acústico externo, no local do registro. A latência das emissões otoacústicas pode ser um instrumento útil para analisar mudanças na maturação coclear assim como os micromecanismos cocleares, já que há uma relação entre a latência das emissões otoacústicas produto de distorção EOAPD e a onda viajante coclear. Estudos em adultos mostram uma diminuição da latência com o aumento da freqüência sonora, variando de 13.8 ms em 787 Hz a 4.4 ms em 5 Hz. Esta diminuição ocorre devido à organização tonotópica da cóclea. São escassos os trabalhos nesta área e não são encontrados critérios de normalidade para estas medidas, principalmente em recém-nascidos. OBJETIVO: Sendo assim, o objetivo deste trabalho foi caracterizar as medidas da latência das EOAPD em neonatos nascidos a termo e não pertencentes ao grupo de risco para perda auditiva. FORMA DE ESTUDO: Caso controle. MATERIAL E MÉTODO: Foram avaliados 31 neonatos, de ambos os sexos e nascidos a termo, sem intercorrências. O procedimento utilizado foi o programa Latencygram. As freqüências testadas foram de 3 a 6 KHz na intensidade de 70 dBNA para f1 e f2. RESULTADO: Os resultados obtidos mostraram uma diminuição da latência com o aumento da freqüência sonora e uma diferença entre os sexos.Latency of distortion product otoacoustic emissions (DPOE is defined as the time that the acoustic stimulus takes to reach the site generating the otoacoustic emission, inside de cochlea, and the return to the external acoustic meatus, to be register. DPOE latency may serve as a useful tool to study cochlear maturational changes as well as the micromechanics of the cochlea, since a relationship between DPE latency and the cochlear traveling wave was observed. Studies on

  17. Tinnitus and normal hearing: a study on the transient otoacoustic emissions suppression Zumbido e audição normal: estudo da supressão das emissões otoacústicas transientes

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    Luciene da Cruz Fernandes

    2009-06-01

    Full Text Available The workings of the auditory pathway of patients with tinnitus and normal hearing can be associated with an auditory efferent pathway dysfunction at the level of the superior olivary complex. Otoacoustic emission suppression with contralateral noise can represent an alternative to its evaluation. AIM:to investigate Transient Otoacoustic Emission suppression in normal hearing adults with and without tinnitus and to compare the two groups. Study design: cross-sectional contemporary cohort. MATERIALS AND METHODS: we assessed 40 female individuals between 18 and 59 years of age, 20 without tinnitus and 20 with it. We studied the TOAE suppression with a contralateral white noise at 50 dBSPL. RESULTS: TOAE amplitude was lower in the group with tinnitus. There was no difference between the groups with and without tinnitus in terms of TOAE suppression, except in the frequency of 1000 Hz in the left ear in the tinnitus group. CONCLUSION: the afferent system assessment may contribute to the topographic diagnosis of tinnitus; however, we still need further studies to establish the proper methodology and normative values to carry out these tests.O funcionamento da via auditiva de pacientes com queixa de zumbido e audição normal pode estar relacionado a uma disfunção da via eferente auditiva, no nível do complexo olivar superior. A supressão das emissões otoacústicas com ruído contralateral pode representar uma alternativa para sua avaliação. OBJETIVO: Investigar a supressão das emissões otoacústicas por estímulo transiente (EOAT em indivíduos adultos, ouvintes normais com e sem queixa de zumbido e comparar os dois grupos. Forma de estudo: Coorte contemporânea com corte transversal. MATERIAL E MÉTODO: Foram avaliados 40 sujeitos, do gênero feminino, entre 18 e 59 anos de idade, sendo 20 sem queixa de zumbido e 20 com queixa de zumbido. Foi realizada a pesquisa da supressão das EOAT com ruído branco contralateral a 50 d

  18. Efeito da acupuntura sobre as emissões otoacústicas de pacientes com zumbido Impact of acupuncture on otoacoustic emissions in patients with tinnitus

    OpenAIRE

    Renata Frasson de Azevedo; Brasilia Maria Chiari; Daniel Mochida Okada; Ektor Tsuneo Onishi

    2007-01-01

    O tratamento do zumbido continua a ser um desafio da atualidade. Na medicina tradicional chinesa, a acupuntura é recomendada para o alívio do zumbido, apesar de faltarem provas cientificas nesta área. OBJETIVO: Verificar o efeito da acupuntura sobre a função coclear de indivíduos com zumbido através do uso das emissões otoacústicas. CASUÍSTICA E MÉTODO: Foi realizado um estudo clínico-prospectivo, no qual foram avaliados 38 pacientes do ambulatório de zumbido. Os pacientes foram avaliados por...

  19. A study on relationship between distortion product otoacoustic emissions and therapeutic effects in tinnitus%畸变产物耳声发射结果与耳鸣疗效的相关性研究

    Institute of Scientific and Technical Information of China (English)

    张静; 周慧芳; 许轶; 张耕

    2009-01-01

    Objective:To find mechanism of tinnitus and explore effective treatment for tinnitus. Method: The 133 tinnitus patients were assigned into two groups by relationship between Distortion product otoacoustic emissions and frequencies of tinnitus: relationship group(73 cases) and non-relationship group(60 cases). All 133 cases were treated with drug,such as injection of Lipo PGE1. Vitamine B1 and VitamineB12 . After 14 days of treatment the efficacy of the medicines in two groups was observed. Result:The effective rate of two groups mentioned above were 75. 3% and 36. 7% respectively( P 0.05).结论:对于DPOAE异常频率与耳鸣的主调存在对应关系的耳鸣患者,尤其是急性耳鸣患者,改善内耳微循环的药物治疗是一种有效的治疗方法.针对不同DPOAE特点的耳鸣患者,应采取个性化的治疗方案.

  20. Otoacoustic interrelationships of the barn owl

    Science.gov (United States)

    Bergevin, Christopher; Manley, Geoffrey A.; Köppl, Christine

    2015-12-01

    Significant debate still exists about the biophysical mechanisms at work in otoacoustic emission (OAE) generation and how such may differ between mammals and non-mammals given gross morphological differences (e.g., existence of basilar membrane traveling waves, degree of tectorial membrane coupling). To further elucidate general principles at work, we examined the barn owl for interrelationships between spontaneous emissions (SOAEs) and those evoked using a single tone (SFOAEs). First, most ears exhibited SOAEs as a stable periodic `rippling' whose peak-to-peak spacing was relatively constant (˜0.4 kHz). Some ears showed substantially larger narrowband peaks, although their statistical distributions were highly noisy. Second, significant interactions between a low-level tone and SOAE activity were observed via an interference pattern as the tone frequency was swept. Using a suppression paradigm to extract SFOAEs as the residual, the magnitude exhibited a stable pattern of peaks and valleys unique to each ear. Third, SFOAE phase exhibited significant accumulation as frequency was swept, with a phase-gradient delay of approximately 2 ms that was constant across frequency. The amount of SFOAE phase accumulation between adjacent SOAE peaks tended to cluster about an integral number of cycles, as previously observed for humans. Taken together, our data suggest that the principles underlying how active hair cells work together (e.g., entrainment, phase coherence) are shared between widely different inner ear morphologies, leading to the generation of OAEs with similar properties.

  1. Quick Detection of Hearing Loss Using Distortion Product Otoacoustic Emissions Evoked by Swept Tones%利用扫频畸变产物耳声发射实现听力损失的快速检测

    Institute of Scientific and Technical Information of China (English)

    陈世雄; 邓军; 李光林

    2013-01-01

      畸变产物耳声发射(Distortion Product Otoacoustic Emission,DPOAE)是在两个固定频率的纯音刺激下,由健康人耳主动向外发射的声音能量。DPOAE 耳声发射信号的存在与人耳的健康状况密切相关,因而它的检测被广泛用于新生儿听力筛查和成人听力检测。然而,目前的 DPOAE 检测技术存在操作复杂、分辨率低、测试时间长等不足。本文提出用频率随时间线性增加的扫频信号替代纯音作为刺激声诱发 DPOAE 耳声发射,以克服当前方法的不足。该扫频方法采用“三段式”播放组合消除刺激声的干扰,并用动态跟踪滤波器从记录到的信号中提取高信噪比的扫频 DPOAE 信号。实验结果表明,扫频 DPOAE 检测方法可以大大缩短 DPOAE 的测量时间,提高检测结果的分辨率,并能灵敏反映受试者听力损失的频率范围。扫频 DPOAE 检测方法的提出,有利于研制一种快速高效的新型耳声发射检测仪,在临床上协助医生进行准确的听力诊断和治疗。%Distortion product otoacoustic emissions (DPOAEs) are sound energy generated by healthy inner ears when stimulated by two fixed-frequency pure tones. Since DPOAEs are physiologically related with the functional status of the inner ears, DPOAE measurement has been widely used in both hearing screening of newborns and hearing diagnoses of adults. However, there are some limitations in current measurements of DPOAE, such as complex operation, insufficient resolution and low efficiency. In this study, a new method in which frequency-varying swept tones were used to replace pure tones to evoke DPOAEs was proposed to overcome the limitations of current methods. In this method, a three-interval paradigm was employed to eliminate the stimulus artifacts and a dynamic tracking filter was used to extract high-quality swept-tone DPOAEs from the recorded signals. The results show that the swept-tone method can

  2. Estudo comparativo entre o aproveitamento escolar de alunos de escola de 1º grau e teste de inibição de emissões otoacústicas transientes Comparative study between school performance on first grade children and suppression of otoacoustic transient emission

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    Miguel Luiz de Sant’Ana Angeli

    2008-02-01

    Full Text Available O processamento auditivo é fundamental para a cognição e pode ocasionar deficiência no aprendizado. Os portadores de sua deficiência podem ser habilitados, melhorando o desempenho escolar. É fundamental identificá-los. Dentre os que apresentam baixo custo e facilidade operacional está o exame de emissões otoacústicas. TIPO DE ESTUDO: Clínico e experimental. OBJETIVO: Estudar a relação do aproveitamento escolar com a inibição da emissão otoacústica transiente por estímulo auditivo contralateral. Material e Métodos: Foram avaliados 39 alunos, de sete a doze anos, sendo 19 (48,7% com bom aproveitamento escolar e 20 (51,3% com aproveitamento inadequado. Os exames emissão otoacústica com inibição contralateral foram comparados aos resultados de aproveitamento escolar. RESULTADOS: A falha da supressão da otoemissão transiente por estímulo acústico contralateral foi mais encontrada no grupo de crianças com mau aproveitamento escolar. Foi estabelecido um valor de corte de 1.6 dB SPL de redução da otoemissão que caracteriza a criança como pertencente ao grupo com mau aproveitamento com sensibilidade de 65,0%, especificidade de 72,2%, acurácia de 68,4% e valor preditivo positivo de 72,2%. CONCLUSÃO: O teste da falha da inibição contralateral da emissão otoacústica por estímulo auditivo contralateral é preditivo de transtorno do aproveitamento escolar em indivíduos de seis a doze anos de idade.School learning can be hampered if there are defects on the central auditory process. Since those with auditory deficiency can be rehabilitated, it is fundamental that we identify them. Otoacoustic emissions test has low cost and operational ease. Study design: clinical and experimental. AIM: to study the relationship between school learning and transient otoacoustic emission suppression by contralateral stimuli. MATERIAL AND METHODS: 39 individuals, from 7 to 12 years of age were evaluated, 19 (48.7% with good school

  3. Crianças com fenilcetonúria: avaliação audiológica básica e supressão das otoemissões Children with phenylketonuria: basic audiological evaluation and suppression of otoacoustic emissions

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    Patrícia Souza Ribeiro

    2012-01-01

    Full Text Available OBJETIVO: Avaliar a via auditiva de crianças com fenilcetonúria tratadas precocemente, por meio de audiometria, imitanciometria e supressão das emissões otoacústicas transientes. MÉTODOS:Estudo prospectivo transversal comparativo com amostra composta por 28 crianças, sendo 12 com fenilcetonúria e 16 sem a doença. Foi realizada a pesquisa dos limiares de audibilidade por via aérea e óssea, logoaudiometria, imitanciometria e supressão das emissões otoacústicas transientes. RESULTADOS: A audiometria e a logoaudiometria estiveram normais em todos os participantes. Foram encontrados piores resultados para o índice de reconhecimento de fala (IRF no grupo com fenilcetonúria. A imitanciometria revelou curva normal para todas as crianças, mas a pesquisa dos reflexos estapedianos demonstrou que as crianças do grupo com fenilcetonúria apresentaram aumento nos seus limiares nas frequências de 2 e 4 kHz. A supressão das emissões otoacústicas transientes não revelou diferença na comparação entre os grupos. CONCLUSÃO: A avaliação audiológica básica não identifica alterações na audição das crianças com fenilcetonúria, mas há pior discriminação ao IRF e aumento nos limiares de reflexos estapedianos nessas crianças, podendo indicar distúrbios do processamento auditivo. O estudo da supressão das otoemissões demonstra integridade do sistema eferente olivococlear medial nas crianças com fenilcetonúria.PURPOSE: To evaluate the auditory pathways of children with early-treated phenylketonuria through audiometry, immitance tests, and suppression of transient otoacoustic emissions. METHODS: Prospective cross-sectional study with sample composed by 28 children: 12 with phenylketonuria and 16 without the disease. Participants underwent auditory evaluations composed of air- and bone-conduction pure-tone audiometry, speech audiometry, immittance tests and suppression of transient otoacoustic emissions. RESULTS: All participants

  4. Clinical value of distortion product otoacoustic emission in tinnitus patients with normal hearing%畸变产物耳声发射测试在听力正常的耳鸣者中的应用价值

    Institute of Scientific and Technical Information of China (English)

    朱小平; 张香玉

    2011-01-01

    Objective To investigate the clinical value of distortion product otoacoustic emission (DPOAE) application in normal hearing patients with tinnitus. Methods A total of 82 healthy volunteers (164 ears) without tinnitus or hearing loss were enrolled as control group and tested with DPOAE. Meanwhile, 84 normal hearing patients (109 ears) with tinnitus were tested with DPOAE before and after 20-days treatment including circulation improvement and supplemental nutrition for inner ear. Results At the frequency of 0.5, 0.75, 1.00, 1.50, 2.00, 3.00, 4.00, 6.00 and 8.00 kHz, the detection rate of DPOAE in tinnitus group was significantly lower than that in control group (all P0.05); the wave height in every frequency was increased after treatment, especially in high frequency (3.00. 4.00, 6.00 and 8.00 kHz, all P< 0.05). Conclusion Tinnitus with normal hearing is likely to be related to hearing loss of super high frequency caused by early impairment of outer hair cells in cochlea. DPOAE examination can be used as an objective assessment for early change of cochlea and periphery tinnitus.%目的 探讨畸变产物耳声发射( DPOAE)测试在听力正常的耳鸣患者中的临床应用价值.方法 对82名(164耳)听力正常且无耳鸣的健康者(对照组)进行DPOAE测试.同时对84例(109耳)听力正常的耳鸣患者(耳鸣组)进行DPOAE测试,并给予改善内耳循环、补充营养等治疗20 d后再次进行DPOAE测试.结果 耳鸣组中,DPOAE测试在0.50、0.75、1.00、1.50、2.00、3.00、4.00、6.00、8.00 kHz各频率点的检出率均显著低于对照组(P值均<0.05).耳鸣组治疗后DPOAE的检出率为43.1%,与治疗前(56.9%)的差异无统计学意义(P>0.05),治疗后在各频率点的DPOAE反应幅值呈提高趋势,尤其在高频(3.00、4.00、6.00、8.00 kHz)的差异有统计学意义(P值均<0.05).结论 听力正常的耳鸣发生可能与耳蜗外毛细胞的早期损伤导致的超高频听力损失有关,DPOAE检测可以

  5. Application of distort product otoacoustic emission(DPOAE)in the tinnitus patients with normal hearing capability%畸变产物耳声发射在听力正常的耳鸣患者中的应用

    Institute of Scientific and Technical Information of China (English)

    邵渊; 安燕; 张少强

    2013-01-01

    Objective To explore the clinical characteristics of the distort product otoacoustic emission( DPOAE )in the tinnitus patients with normal hearing capability and its applied value. Methods DPOAE test was held in 160 tinnitus patients with the normal hearing capability and 120 healthy controls with the normal hearing capability and no tinnitus symptoms. The results were compared between two groups. The tinnitus patients were given nerve-nourishing medicine and vasodilator medicine for consecutive 3 weeks and then DPOAE test was performed again. The results before and after treatment were compared. Results In tinnitus group, the incidence of DPOAE in each frequency was significantly lower than that in healthy controls( P <0. 05 ). After the treatment, the DPOAE reacting amplitudes in high frequency were obviously improved in the tinnitus patients( P < 0. 05 ). Conclusion The occurrence of the tinnitus may be relevant to the cochlear outer hair cell early injury-induced high frequency hearing loss, and DPOAE test can reflect the early stage cochlear injury and act as an objective method for detecting the tinnitus.%目的 探讨听力正常的耳鸣患者畸变产物耳声发射(DPOAE)的临床特点,了解畸变产物耳声发射在耳鸣患者中的应用价值.方法 对160例听力正常伴耳鸣的患者设定为耳鸣组,进行DPOAE测试,同时对120例听力正常且无耳鸣健康者设定为对照组,进行DPOAE测试,对比两组检测结果.对耳鸣患者给予营养神经药物和改善内耳血液循环药物联合治疗3周后再次进行DPOAE测试,对比治疗前后结果.结果 耳鸣组中,DPOAE测试在各频率点的检出率均显著低于健康对照组(P<0.05).耳鸣组经过治疗后,耳声发射在高频段的反应幅值明显提高,与治疗前相比,差异具有统计学意义(P<0.05).结论 耳鸣的产生可能与耳蜗外毛细胞早期损伤导致的高频听力损失相关,DPOAE的检测可反映早期耳蜗病变并可作为耳

  6. Efeito de supressão das emissões otoacústicas evocadas por estímulo transiente em lactentes de risco para perda auditiva nascidos pré-termo Transient otoacoustic emissions suppression in pre-term infants with high risk for hearing loss

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    Aline Mizozoe de Amorim

    2010-10-01

    Full Text Available OBJETIVO: verificar a ocorrência e a magnitude do efeito de supressão das emissões otoacústicas evocadas por estímulo transiente, em lactentes nascidos pré-termo, com indicadores de risco para perda auditiva. MÉTODOS: a supressão das emissões otoacústicas evocadas por estímulo transiente foi realizada em 15 lactentes nascidos pré-termo. O equipamento utilizado foi o ILO USB II V6 Clinical OAE, de marca Ododynamics. O estímulo clique linear foi apresentado a 60 dB pe NPS (± 5 e o ruído contralateral (ruído branco a 60 dB NPS (± 5. RESULTADOS: Dos 15 lactentes, apenas um não apresentou supressão bilateralmente. Dentre os 14, quatro não apresentaram supressão na orelha esquerda. A ocorrência do efeito de supressão foi de 93,3% na população estudada, sendo 71,4% de efeito bilateral e 28,6% de efeito unilateral. Os resultados indicaram diferença estatisticamente significante entre as orelhas. Não foram observadas diferenças estatisticamente significantes com relação as variáveis idade atual e idade gestacional. Os lactentes do sexo masculino apresentaram respostas maiores quando comparados aos do sexo feminino. CONCLUSÕES: a maioria da população estudada apresentou efeito de supressão das emissões otoacústicas. O ruído branco apresentado contralateralmente reduziu o nível de resposta das EOAT, demonstrando a participação do sistema eferente medial no efeito de supressão. As respostas foram diferentes segundo as variáveis lado da orelha e sexo, sendo maiores na orelha direita e no sexo masculino.PURPOSE: to study the occurrence and magnitude of the transient otoacoustic emissions suppression in pre-term infants with high risk for hearing loss. METHODS: the study was carried out in 15 pre-term infants. The used equipment was ILO USB II V6 Clinical OAE Software from Ododynamics. The used stimulation was linear clicks displayed at the intensity of 60 dB pe SPL (± 5. The contralateral noise (white noise was set

  7. Perfil audiométrico e de emissões otoacústicas evocadas por produto de distorção em gestores de trânsito expostos a monóxido de carbono e ruído Audiometric profile and evoked otoacoustic emissions per product of distortion in transit managers, exposed to carbon monoxide and noise

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    Soraya de Carvalho Rocha

    2013-04-01

    Full Text Available OBJETIVO: avaliar o perfil audiométrico e de emissões otoacústicas evocadas por produto de distorção em gestores de trânsito, expostos a monóxido de carbono e ruído, bem como constatar a presença de ambos agentes nos postos de trabalho. MÉTODO:estudo transversal, descritivo, com 37 gestores do trânsito, submetidos a anamnese, meatoscopia, audiometria tonal e emissões otoacústicas, distribuídos em: G1, composto por 18 indivíduos sem histórico de exposição concomitante a monóxido de carbono e ruído; e, G2, formado por 19 trabalhadores expostos simultaneamente aos dois agentes. Para pesquisa da presença dos agentes no ambiente foram utilizadas audiodosímetrias e avaliações de curta duração com medidor instantâneo. As variáveis de anamnese foram analisadas segundo o teste t Student e Mann-Whitney. Para as medidas de otoemissões acústicas e de limiares tonais utilizou-se testes de qui-quadrado (χ2 ou exato de Fisher e dos postos sinalizados de Wilcoxon com significância de 5%. RESULTADOS: foi constatada presença de monóxido de carbono e ruído durante a atividade dos trabalhadores. Não foi observada diferença significante na idade e tempo de função. O G2 obteve média de limiares tonais maior que G1, para orelha direita, em 1KHz (p=0,050 e para orelha esquerda em 3KHz (p=0,016 e 4KHz (p=0,028; e, comparados os limiares tonais alterados G2 apresentou diferença maior em 3KHz na orelha esquerda (p=0,003. Nas emissões otoacústicas, G2 apresentou maior ausência de respostas que G1 em 2.730Hz e 3.218Hz (p=0.016 para orelha direita. CONCLUSÃO: trabalhadores expostos a monóxido de carbono e ruído apresentaram piores resultados audiométricos e nas emissões otoacústicas quando comparado ao grupo de não expostos.PURPOSE: to evaluate the hearing profile and otoacoustic emission evoked by distortion product in Traffic Managers exposed to noise and carbon monoxide, as well as to establish the presence of both agents

  8. Reconhecimento de fala em presença de ruído e suas relações com a supressão das emissões otoacústicas e o reflexo acústico Recognition of speech in noise and relations with suppression of otoacoustic emissions and the acoustic reflex

    Directory of Open Access Journals (Sweden)

    Larissa Lautenschlager

    2011-02-01

    Full Text Available Pessoas com dificuldade para compreensão de fala com som competitivo podem apresentar ausência do efeito de supressão das emissões otoacústicas e do reflexo acústico. OBJETIVO: Estudar o desempenho do sistema auditivo eferente em indivíduos normo-ouvintes com queixa de reconhecer a fala na presença de ruído. MATERIAL E MÉTODO: Estudo prospectivo, com amostra composta por 50 voluntários, com idades entre 19 e 32 anos, normo-ouvintes, que referiram (com queixa-CQ ou não (sem queixa-SQ dificuldade de compreender a fala no ruído. As emissões otoacústicas evocadas produto de distorção (EOAEPDs foram testadas nas frequências de 1500 a 6000Hz. O reflexo acústico contralateral (RAC foi pesquisado nas frequências de 500 a 4000Hz. RESULTADOS: Os grupos diferiram estatisticamente quanto à ocorrência de RAC nas orelhas do lado esquerdo na frequência de 4000Hz. Na frequência de 1500 Hz nas orelhas do lado direito constatou-se predomínio estatisticamente significante da ausência do efeito de supressão das EOAEPDs no grupo CQ. Nas orelhas do lado esquerdo, a ausência do efeito de supressão das EOAEPDs foi maior no grupo CQ em 1500Hz e 2000Hz. CONCLUSÃO: Em normo-ouvintes com autorrelato de dificuldade de reconhecer a fala na presença de ruído verificou-se: ausência de supressão das EOAEPDs nas frequências médias em ambas as orelhas e ausência de reflexo acústico contralateral em 4000Hz na orelha esquerda.Subjects presenting difficulties in understanding speech with competing sounds may have absence of otoacoustic emission suppression and the acoustic reflex. AIM: To study the performance of the efferent auditory system in normal hearing subjects complaining of difficulties to understand speech in noise. MATERIAL AND METHODS: A prospective study comprising 50 normal-hearing subjects aged from 19 to 32 years, reporting difficulties with speech recognition in noise (with complaints - WC or not (with no complaints - WNC

  9. Evoked acoustic emission

    DEFF Research Database (Denmark)

    Elberling, C; Parbo, J; Johnsen, N J;

    1985-01-01

    Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only...... a minor effect on the power spectra, i.e. the maximum jumps from one spectral peak to another. Experiments with deconvolution demonstrate that the emission generating system at least at a fixed intensity can be regarded as being linear and characterized by its impulse response which is similar to...... the emission evoked by click stimuli. It is concluded that significant information is obtained by the click rather than by the tonal stimuli. The click-evoked emissions were also recorded from both ears in a consecutive series of 100 full-term and otherwise normal babies 2-4 days after birth. The...

  10. Emissões otoacústicas x Cisplatina: detecção precoce da ototoxicidade em pacientes oncológicos Otoacoustic emissions x Cisplatin: precocious detection of ototoxicity in oncologic patients

    OpenAIRE

    Ruysdael Zocoli; Sandro Laércio Reichow; Ângela Maria Fontana Zocoli

    2003-01-01

    Estudos mostram que existem numerosas substâncias reconhecidas como potencialmente ototóxicas e entre as principais, na classe dos medicamentos, destacam-se os quimioterápicos. OBJETIVO: o objetivo deste trabalho foi realizar um estudo da ototoxicidade através das emissões otoacústicas evocadas - produto de distorção (EOA-PD), pré e pós-aplicação do quimioterápico Cisplatina, em indivíduos adultos, moradores da cidade de Blumenau/SC. FORMA DE ESTUDO: Prospectivo clínico. MATERIAL E MÉTODO: Fo...

  11. Emissões otoacústicas por produtos de distorção em crianças de 2 a 7 anos Otoacoustic emissions by distorcion products in children of 2 to 7 years old

    Directory of Open Access Journals (Sweden)

    Alfredo R. Dell'Aringa

    2004-06-01

    Full Text Available Com a descoberta das Emissões Otoacústicas (EOA, tornou-se possível analisar e investigar as funções auditivas das células ciliadas externas do órgão da audição. Podem ser espontâneas, evocadas transientes ou por produto de distorção. O teste das EOAEs-DP caracteriza-se por ser um exame objetivo, rápido, indolor, não-invasivo e de fácil aplicação tanto para clínica como para programas de triagem auditiva. FORMA DE ESTUDO: Coorte transversal. MATERIAL E MÉTODO: Foram avaliadas 105 crianças entre 2 e 7 anos de idade da creche "Lar da Criança", de Marília, SP. A avaliação constou de exame otorrinolaringológico completo e EOAEs-DP. Todas estas crianças, após prévia autorização dos responsáveis, foram submetidas a exame otorrinolaringológico completo e EOAEs-DP. RESULTADOS: Os resultados demonstraram que das 105 crianças avaliadas, 44,76% apresentavam cerume. 12 crianças permaneceram com cerume mesmo após uso de ceruminolítico e lavagem auricular ou não apresentaram consentimento informado de seus responsáveis. Portanto, estas foram excluídas do trabalho sendo o restante, 93 crianças, submetidas a avaliação das EOAEs-DP Após a realização das EOAEs-DP, verificou-se que 5,37% das crianças apresentaram exames alterados, sendo que 60% destas eram do sexo masculino e 60% com acometimento bilateral. DISCUSSÃO: Os resultados encontrados foram inferiores aos citados na literatura, assim como o predomínio do sexo masculino. Além disso, notou-se alta prevalência de cerume nos pacientes testados. CONCLUSÃO: É essencial uma avaliação otorrinolaringológica completa prévia. O exame de EOAEs-DP pode ser realizado em crianças para detecção precoce e prevenção de falhas no desenvolvimento cognitivo e psicoemocional.With the discovery of otoacustic emissions it has begun possible to analyze the auditive functions of external hair cells in the auditive cortex. The OAE can be spontaneous transients by

  12. Emissões otoacústicas no diagnóstico precoce de lesão coclear na doença de Ménière Otoacoustic emissions in early diagnosis of cochlear lesions in Ménière's disease

    Directory of Open Access Journals (Sweden)

    Antonio M. C. M. Aquino

    2002-10-01

    Full Text Available Na Doença de Ménière em fase inicial, pode ocorrer surdez flutuante predominante em baixas frequências e também alterações nas otoemissões acústicas (EOA nas freqüências correspondentes àquelas da flutuação, que não são correlacionadas aos limiares auditivos encontrados na audiometria tonal. Estas alterações, experimentalmente, não estão relacionadas à perda de células ciliadas externas (CCE no ápice coclear, sendo que suas causas ainda não são muito claras podendo ser atribuídas às alterações do micromecanismo hidrodinâmico e biomecânico coclear. Assim, as EOA mostraram, neste caso apresentado, alterações cocleares na Doença de Ménière compensada em fase inicial que ainda não são detectadas no audiometria tonal e exames convencionais, sendo portanto um exame que pode mostrar lesão precoce por alteração apenas do micromecanismo coclear.Fluctuating deafness predominating in low frequencies can occur in the early phase of Ménière disease, together with changes in otoacoustic emissions (OAE at the frequencies corresponding to the fluctuating ones, which are not correlated with the auditory thresholds detected in tone audiometry. In experimental studies, these changes are not related to the loss of outer hair cells (OHC in the cochlear apex and their cause is still unclear, possibly corresponding to alterations in the hydrodynamic and biomechanical micromechanism of the cochlea. The OAE observed in the present case showed cochlear alterations in the early compensated phase of Ménière disease which cannot be detected by tone audiometry or standard examinations. Thus, this examination can reveal early lesions due to alterations of the cochlear micromechanism only.

  13. Otoproteção da amifostina aos efeitos ototóxicos da cisplatina: estudo em cobaias albinas por emissões otoacústicas produtos de distorção e microscopia eletrônica de varredura Amifostine otoprotection to cisplatin ototoxicity: a guinea pig study using otoacoustic emission distortion products (DPOEA and scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Miguel Angelo Hyppolito

    2005-06-01

    side effects of cisplatin ototoxicity are significant: irreversible bilateral hearing damage to high frequencies (4 kHz - 8 kHz. Reports recognize some drugs that are associated with cisplatin to obtain an otoprotector effect. The ototoxicity mechanisms of cisplatin are related to injury of hair cell oxidation mechanism, especially of outer hair cells. AIM: Using otoacoustic emissions distortion products (DPOEA and scanning electron microscopy we intended to verify the action of amifostine, a radioprotective drug that has well known antioxidant characteristics and otoprotector effects to cisplatin injury. STUDY DESIGN: Experimental. MATERIAL AND METHODS: We used an experimental guinea pig model. The study was performed as follows: group 1: 6 animals, 12 ears, cisplatin 8.0 mg/Kg/day (IP, 3 days. Group 2: 6 animals, 12 ears, amifostine 100 mg/Kg/day (IP and after 90 minutes, cisplatin 8.0 mg/Kg/day (IP, 3 days and group 3: 3 animals, 6 ears, amifostine 100 mg/Kg/day (IP, 3 days. RESULTS: DPOEA were present before and after treatment in groups 2 and 3. The normal cilium architecture of outer hair cells was supported in all cochlear turns in groups 2 and 3. We concluded that amifostine has a potential otoprotector effect against cisplatin ototoxicity and could be used in clinical trials.

  14. Ocorrência e efeito de supressão das Emissões Otoacústicas em adultos normo-ouvintes com zumbido e hiperacusia Occurrence and suppression effect of Otoacoustic Emissions in normal hearing adults with tinnitus and hyperacusis

    Directory of Open Access Journals (Sweden)

    Daila Urnau

    2012-02-01

    Full Text Available A associação entre zumbido e hiperacusia é frequente na literatura. OBJETIVOS: Verificar a ocorrência e o efeito de supressão das emissões otoacústicas transientes (EOATs, a existência de associação entre graus de zumbido e de hiperacusia, entre efeito supressor das EOATs e lateralidade, graus de zumbido e de hiperacusia, em adultos normo-ouvintes com queixas de zumbido e hiperacusia. MATERIAIS E MÉTODOS: Foram incluídos, nesta forma de estudo transversal, 25 indivíduos normo-ouvintes com queixas de zumbido e hiperacusia. Utilizou-se o Tinnitus Handicap Inventory (THI para classificação do grau do zumbido e o Loudness Discomfort Level (LDL para o da hiperacusia. RESULTADOS: A ocorrência das EOATs variou de 33% a 88%. Houve 63,7% de presença de efeito de supressão na orelha direita e 81,7% na orelha esquerda. Não ocorreu correlação significativa entre os graus de zumbido e os graus de hiperacusia em ambas as orelhas e não houve associação significativa entre efeito de supressão das EOATs e lateralidade, grau de zumbido e de hiperacusia. CONCLUSÃO: A ocorrência de EOATs foi inferior à encontrada em adultos normo-ouvintes. Obteve-se maior percentual de presença do efeito de supressão das EOATs em ambas as orelhas. Não houve associação entre as variáveis analisadas.The association between tinnitus and hyperacusis is common according to the literature. AIM: To verify the occurrence and the suppression effect of transient otoacoustic emissions (TEOAE, the existence of association between tinnitus degrees and hyperacusis degrees, and between the suppressive effect of TEOAE and laterality, tinnitus and hyperacusis degrees in normal hearing adults with complaints of tinnitus and hyperacusis. MATERIALS AND METHODS: 25 normal hearing subjects with complaints of hyperacusis and tinnitus were studied in this cross-sectional study. The Tinnitus Handicap Inventory (THI was used for the classification of tinnitus degrees, and

  15. Repeatability of Transient-Evoked Otoacoustic Emissions in Young Adults

    OpenAIRE

    Kochanek, Krzysztof M.; Śliwa, Lech K.; Puchacz, Klaudia; Piłka, Adam

    2015-01-01

    Background The aim of this study was to evaluate the repeatability and variability of TEOAE characteristics in hearing screening tests performed under practical conditions on normal subjects. Material/Methods A group of 11 young, normal-hearing subjects aged 19–24 years was tested. They were examined otologically and audiologically prior to the tests and no ear pathologies were found. Responses were acquired with a commercially available instrument (Integrity, Vivosonic Inc.) using a standard...

  16. Over-exposure effects on the distortion product otoacoustic emission

    DEFF Research Database (Denmark)

    Reuter, Karen

    with hearing-loss. Reported measurements of OAEs before and after noise exposure suggest that OAE is a more sensitive measure for the hearing function than pure-tone audiometry and therefore might be a measure for the early identification of hearing loss. No individual diagnosis of OAEs is possible...... highly individual and stable over time. No unequivocal relation between the characteristics of the DPOAE fine structure and the state of hearing could be found. It is suggested to eliminate the DPOAE fine structure in the DPOAE measurement and to establish a reference zero from a large amount of DPOAE...... data, to which individual DPOAE levels can be compared....

  17. Experimental Evidence for a Cochlear Source of the Precedence Effect

    DEFF Research Database (Denmark)

    Bianchi, Federica; Verhulst, Sarah; Dau, Torsten

    2013-01-01

    which peripheral versus central auditory processes contribute to this perceptual phenomenon has remained unclear. The present study investigated the contribution of peripheral processing to the PE through a comparison of physiological and psychoacoustical data in the same human listeners. The...... psychoacoustical experiments, comprising a fusion task, an interaural time difference detection task and a lateralization task, demonstrated a time range from 1 to 4.6–5 ms, in which the PE operated (precedence window). Click-evoked otoacoustic emissions (CEOAEs) were recorded in both ears to investigate the lead...

  18. Estudo da audição de crianças de gestantes expostas ao ruído ocupacional: avaliação por emissões otoacústicas - produto de distorção Study of the hearing in children born from pregnant women exposed to occupational noise: assessment by distortion product otoacoustic emissions

    OpenAIRE

    Eduardo Bezerra Rocha; Marisa Frasson de Azevedo; João Aragão Ximenes Filho

    2007-01-01

    OBJETIVO: Detectar precocemente uma possível perda auditiva em crianças de mulheres expostas ao ruído ocupacional durante o período de gestação e verificar se há diferença nos resultados das amplitudes de resposta das emissões otoacústicas - produto de distorção - entre as crianças de mães expostas ao ruído ocupacional e as crianças de mães não-expostas ao ruído ocupacional. MÉTODOS: Crianças de mulheres expostas ao ruído ocupacional durante a gestação e crianças de mulheres não-expostas fora...

  19. Effects of glutamate on distortion-product otoacoustic emissions and auditory brainstem responses in guinea pigs

    Institute of Scientific and Technical Information of China (English)

    SUN Qing; SUN Jian-he; SHAN Xi-zheng; LI Xing-qi

    2008-01-01

    Objective To investigate changes in evoked potentials and structure of the guinea pig cochleae during whole cochlear perfusion with glutamate. Methods CM, CAP, DPOAE, and ABR were recorded as indicators of cochlear functions during whole cochlear perfusion. The morphology of the cochlea was studied via transmission electron microscopy. Results There were no significant changes in DPOAE amplitude before and after glutamate perfusion. CM I/O function remained nonlinear during perfusion. ABR latencies were delayed following glutamate perfusion. The average CAP threshold was elevated 35 dB SPL following glutamate perfusion.. The OHCs appeared normal, but the IHCs and afferent dendrites showed cytoplasmic blebs after glutamate perfusion. Conclusions While being a primary amino acid neurotransmitter at the synapses between hair cells and spiral ganglion neurons, excessive glutamate is neurotoxic and can destroy IHCs and spiral ganglion neurons. The technique used in this study can also be used to build an animal model of auditory neuropathy.

  20. High Frequency Tympanometry in Neonates with Normal Otoacoustic Emissions: Measurements and Interpretations

    OpenAIRE

    Sood, Arvinder Singh; Bons, Charanjit Singh; Narang, Gursharan Singh

    2012-01-01

    Tympanometry is used in evaluating middle ear functional conditions. Before 6 months of age its results may be misleading. High-frequency studies aim to provide more valid procedures. In this study, 236 healthy newborns (127 male, 109 female; 73 % rural, 27 % urban) with age between 0 and 42 days (mean 27 days) no risk for hearing impairment; were analyzed for DPOAE. 209 babies who passed DPOAE were further analyzed for high-frequency tympanometry using Interacoustic AT235h tympanometer, whic...

  1. High frequency tympanometry in neonates with normal otoacoustic emissions: measurements and interpretations.

    Science.gov (United States)

    Sood, Arvinder Singh; Bons, Charanjit Singh; Narang, Gursharan Singh

    2013-07-01

    Tympanometry is used in evaluating middle ear functional conditions. Before 6 months of age its results may be misleading. High-frequency studies aim to provide more valid procedures. In this study, 236 healthy newborns (127 male, 109 female; 73 % rural, 27 % urban) with age between 0 and 42 days (mean 27 days) no risk for hearing impairment; were analyzed for DPOAE. 209 babies who passed DPOAE were further analyzed for high-frequency tympanometry using Interacoustic AT235h tympanometer, which was possible for 399 ears. The success rate for HFT was 95.3 %. Descriptive statistics for six parameters TPP, Y 200, Y peak, Y tail, YpC-200 and Ypc-tail were analyzed and compared with previous studies. All the parameters except the Ypc-tail were in the range of previous studies. PMID:24427574

  2. Stimulus Ratio and Level Dependence of Low- and Mid-Frequency Distortion-Product Otoacoustic Emissions

    DEFF Research Database (Denmark)

    Christensen, Anders Tornvig; Ordoñez, Rodrigo Pizarro; Hammershøi, Dorte

    2014-01-01

    from heartbeating, breathing and swallowing contaminates the measurement. Above 4000 Hz, calibration of the equipment involved is challenging, if not impossible, to do reliably. Here, we investigate alternative measurement parameters to see if the DPOAE is limited to frequencies above 500 Hz. Few...

  3. Distortion product otoacoustic emissions in adult and old Fischer 344 rats

    Czech Academy of Sciences Publication Activity Database

    Popelář, Jiří; Groh, Daniel; Pelánová, Jana; Syka, Josef

    Tübingen : IEB, 2005. s. 95. [42nd workshop on Inner Ear Biology. 18.9.2005-20.9.2005, Tübingen] R&D Projects: GA MZd NR8113; GA ČR GA309/04/1074 Institutional research plan: CEZ:AV0Z50390512 Keywords : F344 Subject RIV: FH - Neurology

  4. Distortion product otoacoustic emission fine structure as an early hearing loss predictor

    DEFF Research Database (Denmark)

    Reuter, Karen; Hammershøi, Dorte

    2006-01-01

    fine structures are obtained from 74 normal-hearing humans using primary levels of L1/L2=65/45 dB. The subjects belong to groups with different ages and exposure histories. A classification algorithm is developed, which quantifies the fine structure by the parameter's ripple place, ripple width, ripple...

  5. A STUDY ON NEONATAL HEARING LOSS USING TRANSIENT EVOKED OTOACOUSTIC EMISSIONS

    Directory of Open Access Journals (Sweden)

    Jayaprabha

    2016-02-01

    Full Text Available Deafness is an invisible disability that may often go undetected until school age, especially in children with no additional disabilities. It affects the social, emotional and cognitive development of an individual. However, this can be overcome through early identification and intervention, for which a screening programme is mandatory. But choosing any option needs realistic assessment of the magnitude of the problem in terms of prevalence as well as the risk factors operating in that specific context. So this study was performed to plan future neonatal screening programmes at Medical College Hospital, Thiruvananthapuram. The study was conducted on 402 babies born at SAT Hospital, Medical College, Thiruvananthapuram. The prevalence of neonatal hearing loss was found to be 0.8%. Craniofacial anomalies, family history of permanent childhood hearing loss and congenital infections were found to be the significant risk factors for hearing loss.

  6. Deriving cochlear delays in humans using otoacoustic emissions and auditory evoked potentials

    DEFF Research Database (Denmark)

    Pigasse, Gilles

    A great deal of the processing of incoming sounds to the auditory system occurs within the cochlear. The organ of Corti within the cochlea has differing mechanical properties along its length that broadly gives rise to frequency selectivity. Its stiffness is at maximum at the base and decreases...... time. Preliminary results are also given for an experiment using stimuli designed to compensate for OAE delays. These were designed to try and reproduce the success of similar stimuli now used routinely to improve ABR signal-to-noise ratio....

  7. Relationship Between Distortion Product – Otoacoustic Emissions (DPOAEs) and High-Frequency Acoustic Immittance Measures

    Science.gov (United States)

    De Paula Campos, Ualace; Hatzopoulos, Stavros; Śliwa, Lech K.; Skarżyński, Piotr H.; Jędrzejczak, Wiesław W.; Skarżyński, Henryk; Carvallo, Renata Mota Mamede

    2016-01-01

    Background Pathologies that alter the impedance of the middle ear may consequently modify the DPOAE amplitude. The aim of this study was to correlate information from 2 different clinical procedures assessing middle ear status. Data from DPOAE responses (both DP-Gram and DP I/O functions) were correlated with data from multi-component tympanometry at 1000 Hz. Material/Methods The subjects were divided into a double-peak group (DPG) and a single-peak group (SPG) depending on 1000 Hz tympanogram pattern. Exclusion criteria (described in the Methods section) were applied to both groups and finally only 31 ears were assigned to each group. The subjects were also assessed with traditional tympanometry and behavioral audiometry. Results Compared to the single-peak group, in terms of the 226 Hz tympanometry data, subjects in the DPG group presented: (i) higher values of ear canal volume; (ii) higher peak pressure, and (iii) significantly higher values of acoustic admittance. DPOAE amplitudes were lower in the DPG group only at 6006 Hz, but the difference in amplitude between the DPG and SPG groups decreased as the frequency increased. Statistical differences were observed only at 1001 Hz and a borderline difference at 1501 Hz. In terms of DPOAE I/O functions, significant differences were observed only in 4 of the 50 tested points. Conclusions The 1000-Hz tympanometric pattern significantly affects the structure of DPOAE responses only at 1001 Hz. In this context, changes in the properties of the middle ear (as detected by the 1000 Hz tympanometry) can be considered as prime candidates for the observed variability in the DP-grams and the DP I/O functions. PMID:27299792

  8. Differences in distortion product otoacoustic emission phase recorded from human neonates using two popular probes

    OpenAIRE

    Abdala, Carolina; Dhar, Sumitrajit

    2010-01-01

    DPOAE (2f1-f2) phase was measured across a 3-octave frequency range from two groups of newborns using ER10B+ and ER10C probe microphones. A marked phase shift was noted in the mid-to-high frequency range for newborn data recorded with the ER10C only. In contrast, the ER10B+ produced phase that was approximately invariant as a function of frequency for most of the range. Probe-related phase shifts can be effectively eliminated by correcting for variations in the phases of the primary tones. Re...

  9. Spontaneous otoacoustic emissions are generated by active oscillators clustered in frequency plateaus

    DEFF Research Database (Denmark)

    Epp, Bastian; Wit, Hero; van Dijk, Pim

    It is commonly assumed that the active process linked to hair-cell motility is an important factor contributing to SOAEs. A chain of coupled, active and nonlinear oscillators with tonotopic organization can be used to account for key aspects of cochlear processing, including SOAEs and related...... phenomena when random irregularities of the mechanical parameters (roughness) are introduced. It was hypothesized that this roughness leads to sudden impedance mismatches leading to multiple reflections of the travelling wave in the cochlea. Recently it was shown [Wit&van Dijk, 2012; J. Acoust. Soc. Am. 132......, 918–926] that a linear array of active oscillators with nearest neighbour coupling produces clusters of oscillators with a common oscillation frequency (frequency plateaus) and a preferred frequency separation. The frequency plateaus can also be entrained to the frequency of an external tone. Both of...

  10. Otoacoustic Emissions in Sudden Sensorineural Hearing Loss: Changes of Measures with Treatment

    Directory of Open Access Journals (Sweden)

    Shadman Nemati

    2011-01-01

    In TEOAEs, the mean overall correlation (reproducibility and the mean overall strength in involved ears were 10.96±23.36 and 0.99±3.45 dB, respectively, before the treatment, which reached 22.88±36.55 and 1.85±5.3, respectively, after the treatment (P>0.05. Significant difference between “correlation score” (average of correlations at 3-4 involved frequencies before and after treatment was found: 6.52 ±18.19 vs. 21.67±37.8 (P

  11. Otoacoustic Emissions in Sudden Sensorineural Hearing Loss: Changes of Measures with Treatment

    Directory of Open Access Journals (Sweden)

    Shadman Nemati

    2011-01-01

    Full Text Available Introduction: To identify changes in OAEs parameters in treatment course of idiopathic sudden sensorineural hearing loss (iSSNHL. Materials and Methods: In aprospective studyfromAugust 2005 to January 2009, 26 patients with iSSNHL underwent conventional audiometry/tympanometry and two types of OAEs (TEOAEs and DPOAEs before and after the completion of standard drug therapy.The changes in pre- and post- treatment parameters were compared with each other and with normal-contralateral ears. Results: In TEOAEs, the mean overall correlation (reproducibility and the mean overall strength in involved ears were 10.96±23.36 and 0.99±3.45 dB, respectively, before the treatment, which reached 22.88±36.55 and 1.85±5.3, respectively, after the treatment (P>0.05. Significant difference between “correlation score” (average of correlations at 3-4 involved frequencies before and after treatment was found: 6.52 ±18.19 vs. 21.67±37.8 (P

  12. Characterizing and modeling dynamic processes in the cochlea using otoacoustic emissions

    DEFF Research Database (Denmark)

    Verhulst, Sarah

    2010-01-01

    An important characteristic of human hearing is that it amplifies weak sounds while attenuating louder ones. This gain transformation takes place in the inner ear (i.e., cochlea), and is responsible for a compressive relation between the level of the presented and perceived sound. The cochlear gain...... mechanism is essential for our hearing and degrades when hearing impairment develops. A comprehensive understanding of the gain involved in the intact human cochlea is crucial, as hearing instruments try to compensate for the loss in cochlear gain caused by hearing damage. This thesis investigates dynamic...... such a time constant in cochlear compression may be of interest for the future development of signal processing in hearing instruments....

  13. Comparison of peripheral compression estimates using auditory steady-state responses (ASSR) and distortion product otoacoustic emissions (DPOAE)

    DEFF Research Database (Denmark)

    Encina Llamas, Gerard; Epp, Bastian; Dau, Torsten

    The healthy auditory system shows a compressive input/output (I/O) function as a result of healthy outer-hair cell function. Hearing impairment often leads to a decrease in sensitivity and a reduction of compression, mainly caused by loss of inner and/or outer hair cells. Compression is commonly...... (DPOAEs) recordings. Results show compressive ASSR I/O functions for NH subjects. For HI subjects, ASSR reveal the loss of sensitivity at low stimulus levels. Growth slopes are smaller (more compressive) in ASSR than in DPOAE I/O functions....

  14. Recovery of Otoacoustic Emission Function in Luetic Endolymphatic Hydrops: A Possible Measure of Improvement in Cochlear Function

    OpenAIRE

    Robert H. Chun; Pinto, Jayant M.; Rebecca Blankenhorn; Dayal, Vijay S.

    2009-01-01

    Syphilis is a preventable and curable multi-organ disease caused by Treponema pallidum that may also affect the inner ear. First reported in 1887 by Adam Politzer, luetic endolymphatic hydrops (LEH) is a treatable complication of syphilis which causes a potentially reversible sensorineural hearing loss. Symptoms of LEH include fluctuating hearing loss (often low frequency), tinnitus, and vertigo. Though audiometric parameters have been examined in patients with otosyphilis, few studies have e...

  15. Effectiveness of Low Level Laser Irradiation on Tinnitus and Parameters of Electrocochleography and Distortion Product Otoacoustic Emissions

    Directory of Open Access Journals (Sweden)

    Saeed Mahmoudian

    2008-06-01

    Full Text Available Background and Aim: Tinnitus is the consciousness of sound that arises in the ear or head without any external sound origin. The efficacies of transmeatal low-level laser irradiation for tinnitus treatment were reported before. The aim of this study was to evaluate the effectiveness of low level laser therapy on tinnitus and ECochG and DPOAEs parameters. Materials and Methods: The study design was prospective, quasi experimental. This investigation conducted on 16 ears (10 patients with disabling tinnitus. All patients underwent ENT examination, complete audiological evaluation, tinnitus study, ECochG and DPOAEs, and finally completing tinnitus data sheet. The results were compared before and after irradiation. Results: Means of tinnitus loudness (LMT and CAP amplitudes were significant different before and after irradiation (p<0.005. There was no any other significant difference before and after low level laser irradiation in subjective loudness, pitch matching annoyance grade of tinnitus and DPOAEs and other ECochG parameters.Conclusion: Transmeatal low-power laser irradiation with 200 mW seems not to be effective for treatment of tinnitus. This paper is the research brief report. In clinical point of view, this study should be repeated with a greater sample size although our results were statistically important.

  16. Physiologic correlates to background noise acceptance

    Science.gov (United States)

    Tampas, Joanna; Harkrider, Ashley; Nabelek, Anna

    2001-05-01

    Acceptance of background noise can be evaluated by having listeners indicate the highest background noise level (BNL) they are willing to accept while following the words of a story presented at their most comfortable listening level (MCL). The difference between the selected MCL and BNL is termed the acceptable noise level (ANL). One of the consistent findings in previous studies of ANL is large intersubject variability in acceptance of background noise. This variability is not related to age, gender, hearing sensitivity, personality, type of background noise, or speech perception in noise performance. The purpose of the current experiment was to determine if individual differences in physiological activity measured from the peripheral and central auditory systems of young female adults with normal hearing can account for the variability observed in ANL. Correlations between ANL and various physiological responses, including spontaneous, click-evoked, and distortion-product otoacoustic emissions, auditory brainstem and middle latency evoked potentials, and electroencephalography will be presented. Results may increase understanding of the regions of the auditory system that contribute to individual noise acceptance.

  17. Using Stimulus Frequency Emissions to Characterize Cochlear Function in Mice

    Science.gov (United States)

    Cheatham, M. A.; Katz, E. D.; Charaziak, K.; Dallos, P.; Siegel, J. H.

    2011-11-01

    Stimulus frequency otoacoustic emissions (SFOAE) were used to assay cochlear function in wildtype and prestin knockin (KI) mice. The latter contain a mutated form of the outer hair cell (OHC) motor protein (V499G/Y501H) with significantly reduced activity. Because several genetic mutations cause accelerated OHC death, it is beneficial to perform experiments in young mice without surgical intervention. Inasmuch as SFOAE thresholds are elevated by only 30 dB in KIs, it is possible to obtain SFOAE tuning functions in these animals. This approach allows sensitivity/frequency selectivity to be assayed within the basilar membane-OHC-tectorial membrane feedback loop, thereby providing information about signal processing prior to inner hair cell stimulation and auditory nerve activation.

  18. Effects of electrical stimulation of the inferior colliculus on 2f1-f2 distortion product otoacoustic emissions in anesthetized guinea pigs

    Czech Academy of Sciences Publication Activity Database

    Popelář, Jiří; Mazelová, Jana; Syka, Josef

    č. 170 (2002), s. 116-126. ISSN 0378-5955 R&D Projects: GA MZd NK6454 Institutional research plan: CEZ:AV0Z5039906 Keywords : inferior colliculus Subject RIV: FH - Neurology Impact factor: 1.969, year: 2002

  19. Brain-derived neurotrophic factor modulates auditory function in the hearing cochlea.

    Science.gov (United States)

    Sly, David J; Hampson, Amy J; Minter, Ricki L; Heffer, Leon F; Li, Jack; Millard, Rodney E; Winata, Leon; Niasari, Allen; O'Leary, Stephen J

    2012-02-01

    Neurotrophins prevent spiral ganglion neuron (SGN) degeneration in animal models of ototoxin-induced deafness and may be used in the future to improve the hearing of cochlear implant patients. It is increasingly common for patients with residual hearing to undergo cochlear implantation. However, the effect of neurotrophin treatment on acoustic hearing is not known. In this study, brain-derived neurotrophic factor (BDNF) was applied to the round window membrane of adult guinea pigs for 4 weeks using a cannula attached to a mini-osmotic pump. SGN survival was first assessed in ototoxically deafened guinea pigs to establish that the delivery method was effective. Increased survival of SGNs was observed in the basal and middle cochlear turns of deafened guinea pigs treated with BDNF, confirming that delivery to the cochlea was successful. The effects of BDNF treatment in animals with normal hearing were then assessed using distortion product otoacoustic emissions (DPOAEs), pure tone, and click-evoked auditory brainstem responses (ABRs). DPOAE assessment indicated a mild deficit of 5 dB SPL in treated and control groups at 1 and 4 weeks after cannula placement. In contrast, ABR evaluation showed that BDNF lowered thresholds at specific frequencies (8 and 16 kHz) after 1 and 4 weeks posttreatment when compared to the control cohort receiving Ringer's solution. Longer treatment for 4 weeks not only widened the range of frequencies ameliorated from 2 to 32 kHz but also lowered the threshold by at least 28 dB SPL at frequencies ≥16 kHz. BDNF treatment for 4 weeks also increased the amplitude of the ABR response when compared to either the control cohort or prior to treatment. We show that BDNF applied to the round window reduces auditory thresholds and could potentially be used clinically to protect residual hearing following cochlear implantation. PMID:22086147

  20. Emission Trading

    OpenAIRE

    Kmoch, Daniel

    2009-01-01

    The work concerns Emission Trading Scheme from perspektive of taxes and accounting. I should show problems with emission trading. The work concerns practical example of trading with emission allowance.

  1. Emissions Trading

    NARCIS (Netherlands)

    Woerdman, Edwin; Backhaus, Juergen

    2014-01-01

    Emissions trading is a market-based instrument to achieve environmental targets in a cost-effective way by allowing legal entities to buy and sell emission rights. The current international dissemination and intended linking of emissions trading schemes underlines the growing relevance of this instr

  2. Emission Facilities - Air Emission Plants

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Represents the Primary Facility type Air Emission Plant (AEP) point features. Air Emissions Plant is a DEP primary facility type related to the Air Quality Program....

  3. Emission inventory; Inventaire des emissions

    Energy Technology Data Exchange (ETDEWEB)

    Fontelle, J.P. [CITEPA, Centre Interprofessionnel Technique d`Etudes de la Pollution Atmospherique, 75 - Paris (France)

    1997-12-31

    Statistics on air pollutant (sulfur dioxide, nitrogen oxides and ammonium) emissions, acid equivalent emissions and their evolution since 1990 in the various countries of Europe and the USA, are presented. Emission data from the industrial, agricultural, transportation and power sectors are given, and comparisons are carried out between countries based on Gnp and population, pollution import/export fluxes and compliance to the previous emission reduction objectives

  4. Acoustic emission

    International Nuclear Information System (INIS)

    This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

  5. Is Emission Trading Beneficial?

    OpenAIRE

    ISHIKAWA Jota; Kiyono, Kazuharu; YOMOGIDA Morihiro

    2011-01-01

    We develop a two-country (North and South), two-good, general equilibrium model of international trade in goods and explore the effects of domestic and international emission trading under free trade in goods. Whereas domestic emission trading in North may result in carbon leakage by expanding South’s production of the emission-intensive good, international emission trading may induce North to expand the production of the emission-intensive good by importing emission permits. Emission trading...

  6. Is Emission Trading Beneficial?

    OpenAIRE

    ISHIKAWA Jota; Kiyono, Kazuharu; YOMOGIDA Morihiro

    2011-01-01

    We develop a two-country (North and South), two-good, general equilibrium model of international trade in goods and explore the effects of domestic and international emission trading under free trade in goods. Whereas domestic emission trading in North may result in carbon leakage by expanding South's production of the emission-intensive good, international emission trading may induce North to expand the production of the emission-intensive good by importing emission permits. Emission trading...

  7. Emission Inventory for Fugitive Emissions in Denmark

    DEFF Research Database (Denmark)

    Plejdrup, Marlene Schmidt; Nielsen, Ole-Kenneth; Nielsen, Malene

    This report presents the methodology and data used in the Danish inventory of fugitive emissions from fuels for the years until 2007. The inventory of fugitive emissions includes CO2, CH4, N2O, NOx, CO, NMVOC, SO2, dioxin, PAH and particulate matter. In 2007 the total Danish emission of greenhouse...... gasses was 66 641 Gg CO2-eqvivalents. Fugitive emissions from fuels account for 496 Gg CO2-eqvivalents or approximately 1 %. The major part of the fugitive emissions are emitted as CO2 (74 %) due to flaring of oil and gas. The major source of fugitive CH4 emission is extraction of oil and gas in the...... North Sea, refining of oil and loading of oil onto ships both offshore and onshore. The fugitive emissions of NMVOC originate for the major part from extraction, loading of ships, transmission and distribution of oil and to a much lesser degree from natural gas and fugitive emissions from gas stations...

  8. Criteria Air Emissions Trends

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Air Emissions Trends site provides national trends of criteria pollutant and precursor emissions data based on the the National Emissions Inventory (NEI) from...

  9. Moderate emissions grandfathering

    OpenAIRE

    Knight, Carl

    2014-01-01

    Emissions grandfathering holds that a history of emissions strengthens an agent’s claim for future emission entitlements. Though grandfathering appears to have been influential in actual emission control frameworks, it is rarely taken seriously by philosophers. This article presents an argument for thinking this an oversight. The core of the argument is that members of countries with higher historical emissions are typically burdened with higher costs when transitioning to a given lower level...

  10. Ion cyclotron emission by spontaneous emission

    Energy Technology Data Exchange (ETDEWEB)

    Da Costa, O. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Gresillon, D. [Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises

    1994-07-01

    The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs.

  11. Vehicle Emissions Risk Management

    International Nuclear Information System (INIS)

    Vehicle emissions are considered as a main source for air pollution. Emissions regulation is now well developed in most countries to meet cleaner air quality. Reducing emissions by using cleaner fuels, which meet certain specification, is not enough to get cleaner air, yet the vehicle technology is not improved. Here we will outline the following: - development in fuel specification and emissions regulation. main facts linking vehicle emissions, fuel properties and air quality. catalytic converter technology. Emissions sources: In modem cities, vehicle traffic is potentially a major source of emissions. However sometimes other sources of emissions from industry and other stationary sources can be equally important and include emissions that are of greater toxicity than those from vehicles

  12. 47 CFR 74.637 - Emissions and emission limitations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Emissions and emission limitations. 74.637... Auxiliary Stations § 74.637 Emissions and emission limitations. (a) The mean power of emissions shall be... more than 50%: at least 50 dB below peak power of the emission. (b) For all emissions not covered...

  13. National Emission Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Emission Inventory contains measured, modeled, and estimated data for emissions of all known source categories in the US (stationary sources, fires,...

  14. Control of Emissions

    Science.gov (United States)

    Parrish, Clyde F. (Inventor); Chung, Landy (Inventor)

    2013-01-01

    Methods and apparatus utilizing chlorine dioxide and hydrogen peroxide are useful to reduce NOx emissions, as well as SOx and mercury (or other heavy metal) emissions, from combustion flue gas streams.

  15. Emissões otoacústicas por produtos de distorção na paralisia de Bell Distortion product otoacustic emissions in Bell's palsy

    Directory of Open Access Journals (Sweden)

    Cristiane A. Kasse

    2002-10-01

    Full Text Available Introdução: O núcleo do nervo facial e do núcleo olivar superior são conectados por fibras, desta forma uma lesão nesta conecção poderia interferir na função das células ciliadas externas, alterando o exame de emissão otoacústica por produtos de distorção (EOAPD. Objetivo: Observar a possibilidade da paralisia de Bell afetar a função das células ciliadas externas através da EOAPD. Forma do Estudo: Prospectivo clínico. Material e Método: Quarenta pacientes com paralisia de Bell foram comparados com 69 pacientes normais (grupo controle, usando EOAPD. Resultados: Os pacientes com paralisia de Bell e EOAPD alterados foram de 17,5% e no grupo controle de 7,2%, sem diferença estatística entre os valores. Não se observou também uma correlação entre o reflexo estapediano e o grau da paralisia facial com a EOAPD. Conclusão: Não observamos correlação entre EOAPD e a paralisia de Bell.Introduction: The facial nucleus and olivar nucleus are connected with fibers, then a lesion in this conection could interfer in the outer cell function changing the result of otoacoustic emission product distortion test (DPOE. Objective: To observe the possibility of Bell's palsy affect the function of outer hair cells, using the DPOE test. Study Design: Prospective clinical. Material and Method: Forty patients with Bell's palsy were compared with 69 patients without symptons (control group using DPOE. Results: The patients with Bell's palsy without DPOE response were 17.5% and in the control group, 7.2%, without statistical difference between them. We did not observe a correlation with stapedium reflex and degree of palsy and DPOE. Conclusion: There was no correlation with Bell's palsy and DPOE.

  16. Pulse emission mechanisms

    OpenAIRE

    Melrose, Don

    2003-01-01

    High-energy and radio emission mechanisms for pulsars are reviewed. The source region for high energy emission remains uncertain. Two preferred radio emission mechanism are identified. Some difficulties may be resolved by appealing to nonstationary pair creation distributed widely in height.

  17. Otoproteção da amifostina aos efeitos ototóxicos da cisplatina: estudo em cobaias albinas por emissões otoacústicas produtos de distorção e microscopia eletrônica de varredura Amifostine otoprotection to cisplatin ototoxicity: a guinea pig study using otoacoustic emission distortion products (DPOEA) and scanning electron microscopy

    OpenAIRE

    Miguel Angelo Hyppolito; Antonio A. de Oliveira; Ricardo Miranda Lessa; Maria Rossato

    2005-01-01

    A Cisplatina é uma potente droga antineoplásica, largamente utilizada para o tratamento do câncer, tanto em adultos quanto em crianças. Dentre seus efeitos colaterais, a ototoxicidade se apresenta como um dos mais importantes e leva à perda auditiva irreversível, bilateral, para as altas freqüências (4KHz -8KHz). Estudos têm tentado identificar drogas que, associadas à cisplatina, possam atuar como otoprotetores. Sabe-se que o mecanismo da ototoxicidade pela cisplatina está relacionado a alte...

  18. International emissions trading

    DEFF Research Database (Denmark)

    Boom, Jan Tjeerd

    This thesis discusses the design and political acceptability of international emissions trading. It is shown that there are several designs options for emissions trading at the national level that have a different impact on output and thereby related factors such as employment and consumer prices....... The differences in impact of the design make that governments may prefer different designs of emissions trading in different situations. The thesis furthermore establishes that international emissions trading may lead to higher overall emissions, which may make it a less attractive instrument....

  19. Shipping emissions in ports

    OpenAIRE

    Olaf MERK

    2014-01-01

    Shipping emissions in ports are substantial, accounting for 18 million tonnes of CO2 emissions, 0.4 million tonnes of NOx, 0.2 million of SOx and 0.03 million tonnes of PM10 in 2011. Around 85% of emissions come from containerships and tankers. Containerships have short port stays, but high emissions during these stays. Most of CO2 emissions in ports from shipping are in Asia and Europe (58%), but this share is low compared to their share of port calls (70%). European ports have much less emi...

  20. Galactic Diffuse Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Digel, Seth W.; /SLAC

    2007-10-25

    Interactions of cosmic rays with interstellar nucleons and photons make the Milky Way a bright, diffuse source of high-energy {gamma}-rays. Observationally, the results from EGRET, COMPTEL, and OSSE have now been extended to higher energies by ground-based experiments, with detections of diffuse emission in the Galactic center reported by H.E.S.S. in the range above 100 GeV and of diffuse emission in Cygnus by MILAGRO in the TeV range. In the range above 100 keV, INTEGRAL SPI has found that diffuse emission remains after point sources are accounted for. I will summarize current knowledge of diffuse {gamma}-ray emission from the Milky Way and review some open issues related to the diffuse emission -- some old, like the distribution of cosmic-ray sources and the origin of the 'excess' of GeV emission observed by EGRET, and some recently recognized, like the amount and distribution of molecular hydrogen not traced by CO emission -- and anticipate some of the advances that will be possible with the Large Area Telescope on GLAST. We plan to develop an accurate physical model for the diffuse emission, which will be useful for detecting and accurately characterizing emission from Galactic point sources as well as any Galactic diffuse emission from exotic processes, and for studying the unresolved extragalactic emission.

  1. Low Emissions Aftertreatment and Diesel Emissions Reduction

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-05-27

    Detroit Diesel Corporation (DDC) has successfully completed a five-year Low Emissions Aftertreatment and Diesel Emissions Reduction (LEADER) program under a DOE project entitled: ''Research and Development for Compression-Ignition Direct-Injection Engines (CIDI) and Aftertreatment Sub-Systems''. The objectives of the LEADER Program were to: Demonstrate technologies that will achieve future federal Tier 2 emissions targets; and Demonstrate production-viable technical targets for engine out emissions, efficiency, power density, noise, durability, production cost, aftertreatment volume and weight. These objectives were successfully met during the course of the LEADER program The most noteworthy achievements in this program are listed below: (1) Demonstrated Tier 2 Bin 3 emissions target over the FTP75 cycle on a PNGV-mule Neon passenger car, utilizing a CSF + SCR system These aggressive emissions were obtained with no ammonia (NH{sub 3}) slip and a combined fuel economy of 63 miles per gallon, integrating FTP75 and highway fuel economy transient cycle test results. Demonstrated feasibility to achieve Tier 2 Bin 8 emissions levels without active NOx aftertreatment. (2) Demonstrated Tier 2 Bin 3 emissions target over the FTP75 cycle on a light-duty truck utilizing a CSF + SCR system, synergizing efforts with the DOE-DDC DELTA program. This aggressive reduction in tailpipe out emissions was achieved with no ammonia slip and a 41% fuel economy improvement, compared to the equivalent gasoline engine-equipped vehicle. (3) Demonstrated Tier 2 near-Bin 9 emissions compliance on a light-duty truck, without active NOx aftertreatment devices, in synergy with the DOE-DDC DELTA program. (4) Developed and applied advanced combustion technologies such as ''CLEAN Combustion{copyright}'', which yields simultaneous reduction in engine out NOx and PM emissions while also improving engine and aftertreatment integration by providing favorable

  2. BP's emissions trading system

    International Nuclear Information System (INIS)

    Between 1998 and 2001, BP reduced its emissions of greenhouse gases by more than 10%. BP's success in cutting emissions is often equated with its use of an apparently market-based emissions trading program. However no independent study has ever examined the rules and operation of BP's system and the incentives acting on managers to reduce emissions. We use interviews with key managers and with traders in several critical business units to explore the bound of BP's success with emissions trading. No money actually changed hands when permits were traded, and the main effect of the program was to create awareness of money-saving emission controls rather than strong price incentives. We show that the trading system did not operate like a 'textbook' cap and trade scheme. Rather, the BP system operated much like a 'safety valve' trading system, where managers let the market function until the cost of doing so surpassed what the company was willing to tolerate

  3. High Altitude Emissions

    Science.gov (United States)

    Bulzan, Dan

    2007-01-01

    An overview of emissions related research being conducted as part of the Fundamental Aeronautics Supersonics Project is presented. The overview includes project objectives, milestones, and descriptions of major research areas. The overview also includes information on the emissions research being conducted under NASA Research Announcements. Technical challenges include: 1) Environmental impact of supersonic cruise emissions is greater due to higher flight altitudes which makes emissions reduction increasingly important. 2) Accurate prediction tools to enable combustor designs that reduce emissions at supersonic cruise are needed as well as intelligent systems to minimize emissions. 3) Combustor operating conditions at supersonic cruise are different than at subsonic cruise since inlet fuel and air temperatures are considerably increased.

  4. Electrical modulation of emissivity

    OpenAIRE

    Vassant, Simon; Moldovan Doyen, Ioana Cristina; Marquier, François; Pardo, F.; Gennser, Ulf; Cavanna, Antonella; Pelouard, Jean-Luc; Greffet, Jean-Jacques

    2013-01-01

    We demonstrate that it is possible to modulate the thermal emission through an electrical modulation of the emissivity. The basic idea is to design a device where absorption is due to a resonant phenomenon. If the resonance can be electrically controlled, then absorption and, therefore, thermal emission can be controlled. We demonstrate this general concept using THz resonant absorption by surface phonon polaritons coupled through a gold grating. In our device, absorption is mostly due to a s...

  5. Global Seabird Ammonia Emissions

    Science.gov (United States)

    Riddick, S. N.; Blackall, T. D.; Dragosits, U.; Daunt, F. H.; Braban, C. F.; Tang, Y. S.; Trathan, P.; Wanless, S.; Sutton, M. A.

    2010-12-01

    Seabird colonies represent a major source of atmospheric ammonia (NH3) in remote coastal and marine systems in temperate, tropical and polar regions. Previous studies have shown that NH3 emissions from Scottish seabird colonies were substantial - of similar magnitude to the most intensive agricultural point source emissions. The UK data were used to model global seabird NH3 emissions and suggested that penguins are a major source of emissions on and around the Antarctic continent. The largest seabird colonies are in the order of millions of seabirds. Due to the isolation of these colonies from anthropogenic nitrogen sources, they may play a major role in the nitrogen cycle within these ecosystems. A global seabird database was constructed and used in conjunction with a species-specific seabird bioenergetics model to map the locations of NH3 emissions from seabird colonies. The accuracy of the modelled emissions was validated with field data of NH3 emissions measured at key seabird colonies in different climatic regions of the world: temperate (Isle of May, Scotland), tropical (Ascension Island) and polar (Signy Island, South Georgia). The field data indicated good agreement between modelled and measured NH3 emissions. The measured NH3 emissions also showed the variability of emission with climate. Climate dependence of seabird NH3 emissions may have further implications under a changing global climate. Seabird colonies represent NH3 emission ‘hotspots’, often far from anthropogenic sources, and are likely to be the major source of nitrogen input to these remote coastal ecosystems. The direct manuring by seabirds at colony locations may strongly influence species richness and biodiversity. The subsequent volatilisation and deposition of NH3 increases the spatial extent of seabird influence on nitrogen cycling in their local ecosystem. As many seabird populations are fluctuating due to changing food supply, climate change or anthropogenic pressures, these factors

  6. Smokestack emission control apparatus

    International Nuclear Information System (INIS)

    A smokestack emissions control device is mounted to a smokestack, or the like, to clean and cool the emissions from the stack. The apparatus includes a housing shaped to be mounted on top of an emission stack and has a liquid tank formed in the housing for supporting a liquid therein. The tank is mounted directly in the passageway of escaping emissions to force the emissions through the liquid. A tank baffle extends into the liquid tank and into a liquid therein to force the escaping emissions from the smokestack through the liquid. A reduced pressure chamber is located adjacent to the liquid tank to create a negative pressure on one side of the liquid in the tank to draw the smokestack emissions through the liquid. A separator is located near the base of the stack wit pipes connecting the separator to the liquid bath for circulating the liquid in the liquid tank. the liquid in the bath can be specially formulated for the particular emissions from the emission stack. Anti-foaming and bubbling means are included to prevent the liquid from forming out of the tank. The tank is lightweight and allows the entire apparatus to be placed on an existing exhaust stack

  7. Graphene field emission devices

    OpenAIRE

    DUESBERG, GEORG

    2014-01-01

    PUBLISHED Graphene field emission devices are fabricated using a scalable process. The field enhancement factors, determined from the Fowler-Nordheim plots, are within few hundreds and match the theoretical predictions. The devices show high emission current density of ∼10 nA μm−1 at modest voltages of tens of volts. The emission is stable with time and repeatable over long term, whereas the noise in the emission current is comparable to that from individual carbon nanotubes emitting under...

  8. Ammonia emissions in Europe

    DEFF Research Database (Denmark)

    Jacobsen, Brian H.

    2012-01-01

    The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the...... technology is adopted quicker and that the farm has the right location. It is concluded that the new application process so far has not lived up to the high expectations at the outset. Despite this, the paper concludes that Denmark is likely to reduce emission by 50% from 1990 to 2020 and reach the likely...

  9. VOC emissions chambers

    Data.gov (United States)

    Federal Laboratory Consortium — In order to support the development of test methods and reference materials for volatile organic compounds (VOC) emissions from building materials and furnishings,...

  10. Toluene emissions from plants

    Science.gov (United States)

    Heiden, A. C.; Kobel, K.; Komenda, M.; Koppmann, R.; Shao, M.; Wildt, J.

    The emission of toluene from different plants was observed in continuously stirred tank reactors and in field measurements. For plants growing without stress, emission rates were low and ranged from the detection limit up to 2·10-16 mol·cm-2·s-1. Under conditions of stress, the emission rates exceeded 10-14 mol·cm-2·s-1. Exposure of sunflower (Helianthus annuus L. cv. Gigantheus) to 13CO2 resulted in 13C-labeling of the emitted toluene on a time scale of hours. Although no biochemical pathway for the production of toluene is known, these results indicate that toluene is synthesized by the plants. The emission rates of toluene from sunflower are dependent on nutrient supply and wounding. Since α-pinene emission rates are also influenced by these factors, toluene and α-pinene emissions show a high correlation. During pathogen attack on Scots pines (Pinus sylvestris L.) significant toluene emissions were observed. In this case emissions of toluene and α-pinene also show a good correlation. Toluene emissions were also found in field experiments with pines using branch enclosures.

  11. Air Emission Inventory for the INEEL -- 1999 Emission Report

    Energy Technology Data Exchange (ETDEWEB)

    Zohner, Steven K

    2000-05-01

    This report presents the 1999 calendar year update of the Air Emission Inventory for the Idaho National Engineering and Environmental Laboratory (INEEL). The INEEL Air Emission Inventory documents sources and emissions of nonradionuclide pollutants from operations at the INEEL. The report describes the emission inventory process and all of the sources at the INEEL, and provides nonradionuclide emissions estimates for stationary sources.

  12. 47 CFR 78.103 - Emissions and emission limitations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Emissions and emission limitations. 78.103... CABLE TELEVISION RELAY SERVICE Technical Regulations § 78.103 Emissions and emission limitations. (a) A CARS station may be authorized to employ any type of emission, for which there are technical...

  13. Poultry housing emissions perspective

    Science.gov (United States)

    Concerns for climate change are expanding interest in greenhouse gas (GHG) emissions from all agricultural sectors; animal production systems are no exception. The focus of this overview is to compare emission factors among egg and meat bird poultry operations, specifically layer and broiler chicke...

  14. Observed Barium Emission Rates

    Science.gov (United States)

    Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

    1993-01-01

    The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

  15. Emissions of road transport

    International Nuclear Information System (INIS)

    Information on the emissions and energy consumption of different vehicles per transported amount of goods has up to last years been minimal. The unit emissions mean the amount of harmful compounds in the flue gases of a vehicle per service, time or energy unit. National three-year MOBILE 2-research program, started in 1999, determines the unit emissions of all the traffic sectors in Finland. VTT Building and Transport mainly carry out the research, but the Institute of Transportation Engineering of the Tampere University of Technology (TTKK) is responsible for a part of the research. The objective of the project is to create common rules for the determination of unit emissions values, and to determine the best possible values for Finnish conditions. Unit emission data is mainly needed for evaluation of the environmental impacts of production plants and other activities containing transportation of commodities. At the web sites of VTT Building and Transport there are about 60 pages of text and tables (about 4000 values) on unit emissions. The URL of the pages is http://www.vtt.fi/rte/projects/lipastoe/index.htm. These web pages present data on all the transportation sectors (road, railroad, water and air transportation), most of the materials concerning road transportation. Following compounds and values are included: CO, HC, NOx, particulates, SO2, CO2 and energy consumption. Methane and nitrous oxide emissions values have also been presented

  16. Controlling spontaneous emission

    DEFF Research Database (Denmark)

    Lodahl, Peter

    Control over spontaneous emission of light is of great importance in quantum optics. It is essential for diverse applications such as miniature lasers, light-emitting diodes, and single-photon sources for quantum information. We present experimental studies on spontaneous emission of CdSe quantum...... dots (QDs) embedded in 3D photonic crystals consisting of air spheres in titanium dioxide. Performing time-resolved experiments, we show that the photonic crystals control the emission decay rate of excitons confined in the QDs1,2. By varying the lattice parameter of the photonic crystals, we...

  17. Emission sources and quantities

    International Nuclear Information System (INIS)

    The paper examines emission sources and quantities for SO2 and NOx. Natural SO2 is released from volcanic sources and to a much lower extent from marsh gases. In nature NOx is mainly produced in the course of the chemical and bacterial denitrification processes going on in the soil. Manmade pollutants are produced in combustion processes. The paper concentrates on manmade pollution. Aspects discussed include: mechanism of pollution development; manmade emission sources (e.g. industry, traffic, power plants and domestic sources); and emission quantities and forecasts. 11 refs., 2 figs., 5 tabs

  18. Emissivity: A Program for Atomic Emissivity Calculations

    OpenAIRE

    Sochi, Taha

    2009-01-01

    In this article we report the release of a new program for calculating the emissivity of atomic transitions. The program, which can be obtained with its documentation from our website www.scienceware.net, passed various rigorous tests and was used by the author to generate theoretical data and analyze observational data. It is particularly useful for investigating atomic transition lines in astronomical context as the program is capable of generating a huge amount of theoretical data and comp...

  19. National Greenhouse Gas Emission Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Greenhouse Gas Emission Inventory contains information on direct emissions of greenhouse gases as well as indirect or potential emissions of greenhouse...

  20. 2011 NATA - Emissions Sources

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes all emissions sources that were modeled in the 2011 National Air Toxics Assessment (NATA), inlcluding point, nonpoint, and mobile sources, and...

  1. The Carbon Emission Game

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    When Chinese President Hu Jintao attended the UN climate summit on September22,he made a solemn commitment that China will cut its per GDP unit carbon emission to a significant amount in 2020 compared with that of 2005.

  2. Polarization Dependence of Emissivity

    OpenAIRE

    J, David; Strozzi,, A.G.; McDonald, Kirk T.

    2000-01-01

    We deduce the emissivity of radiation from a metallic surface as a function of angle and polarization. This effect has found application in the calibration of detectors for cosmic microwave background radiation.

  3. National Emission Inventory (NEI)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data exchange allows states to submit data to the US Environmental Protection Agency's National Emissions Inventory (NEI). NEI is a national database of air...

  4. Photon enhanced thermionic emission

    Science.gov (United States)

    Schwede, Jared; Melosh, Nicholas; Shen, Zhixun

    2014-10-07

    Photon Enhanced Thermionic Emission (PETE) is exploited to provide improved efficiency for radiant energy conversion. A hot (greater than 200.degree. C.) semiconductor cathode is illuminated such that it emits electrons. Because the cathode is hot, significantly more electrons are emitted than would be emitted from a room temperature (or colder) cathode under the same illumination conditions. As a result of this increased electron emission, the energy conversion efficiency can be significantly increased relative to a conventional photovoltaic device. In PETE, the cathode electrons can be (and typically are) thermalized with respect to the cathode. As a result, PETE does not rely on emission of non-thermalized electrons, and is significantly easier to implement than hot-carrier emission approaches.

  5. Galactic Diffuse Polarized Emission

    Indian Academy of Sciences (India)

    Ettore Carretti

    2011-12-01

    Diffuse polarized emission by synchrotron is a key tool to investigate magnetic fields in the Milky Way, particularly the ordered component of the large scale structure. Key observables are the synchrotron emission itself and the RM is by Faraday rotation. In this paper the main properties of the radio polarized diffuse emission and its use to investigate magnetic fields will be reviewed along with our current understanding of the galactic magnetic field and the data sets available. We will then focus on the future perspective discussing RM-synthesis – the new powerful instrument devised to unlock the information encoded in such an emission – and the surveys currently in progress like S-PASS and GMIMS.

  6. Methane emissions from vehicles.

    Science.gov (United States)

    Nam, E K; Jensen, T E; Wallington, T J

    2004-04-01

    Methane (CH4) is an important greenhouse gas emitted by vehicles. We report results of a laboratory study of methane emissions using a standard driving cycle for 30 different cars and trucks (1995-1999 model years) from four different manufacturers. We recommend the use of an average emission factor for the U.S. on-road vehicle fleet of (g of CH/g of CO2) = (15 +/- 4) x 10(-5) and estimate that the global vehicle fleet emits 0.45 +/- 0.12 Tg of CH4 yr(-1) (0.34 +/- 0.09 Tg of C yr(-1)), which represents effects of vehicle aging, cold start, and hot running emissions. The contribution of CH4 emissions from vehicles to radiative forcing of climate change is 0.3-0.4% of that of CO2 emissions from vehicles. The environmental impact of CH4 emissions from vehicles is negligible and is likely to remain so for the foreseeable future. PMID:15112800

  7. DC field emission

    International Nuclear Information System (INIS)

    The field emission project at the University of Geneva aims on the one hand at the understanding of the physical mechanism of the Enhanced Field Emission (EFE) which today is still unclear and on the other hand at the controlled production and elimination of field emitting sites. The experimental system basically consists of a UHV apparatus including Scanning Auger, SEM, and a specially constructed precision sample manipulator allowing to obtain field emission (FE) scans over 12 mm diameter cathodes at fields of 100 MV/m and higher. Also, FE sites can be localized with micrometer precision and analyzed in situ. With this experimental facility, the effect of heat treatment on niobium has been studied, and it has been found that heat treatment at high temperatures (> 10000C) reliably reduces EFE. Completely emission-free cathodes at 100 MV/m are regularly obtained. Heat treatments at 6000C ≤ T ≤ 8000C makes new FE sites appear, even from emission-free cathodes. These emission sites are predominantly carbon (graphite) and MoS2 particles. Experiments on artificially deposited graphite and MoS2 particles have shown that it is possible to locally create emitters which are similar to the natural emitters: field enhancement factors β of 100 and higher from micron size particles or submicron features can be obtained. Typical emitting particles of these materials have been found to reflect the two-dimensional crystal structure: they appear as thin, bright flakes under the SEM. 6 references

  8. Economical benzene emission reduction

    International Nuclear Information System (INIS)

    Benzene has been classified as a toxic compound under the Canadian Environmental Protection Act. This has prompted the Alberta Energy and Utilities Board (AEUB) to introduce specific reporting and monitoring guidelines for the oil and gas industry regarding excessive benzene emissions. Glycol dehydration units have been determined to be the major single source of benzene emissions causing air and soil pollution. DualTank Corp. has designed a condensation and storage tank unit to enhance emission reduction, odour elimination and liquid recovery from dehydration units. Their newly designed combined tank unit consists of a large, uninsulated surface area for cooling, and an excessive internal volume for increased retention time. The first prototype was installed in December 1998 at an Enerplus Resources Site. The system provides excellent benzene emission reduction and the elimination of odours and visual plumes. Effective January 1, 1999, the petroleum and natural gas industry must either clean up excessive emissions voluntarily or face government imposed regulations, facility shutdowns and/or fines. 1 fig

  9. Carbon emissions control strategies

    International Nuclear Information System (INIS)

    This study was undertaken to address a fundamental issue: the cost of slowing climate change. Experts in eight nations were asked to evaluate, using the best economic models available, the prospects for reducing fossil fuel-based carbon emissions in their respective nations. The nations selected as case studies include: the Soviet Union, Poland, the United States, Japan, Hungary, France, the United Kingdom, and Canada. As important contributors to the greenhouse effect, these industrialized nations must find ways to substantially reduce their emissions. This is especially critical given that developing nations' emissions are expected to rise in the coming decades in the search for economic development. Ten papers have been processed separately for inclusion in the appropriate data bases

  10. Emissivity of microstructured silicon.

    Science.gov (United States)

    Maloney, Patrick G; Smith, Peter; King, Vernon; Billman, Curtis; Winkler, Mark; Mazur, Eric

    2010-03-01

    Infrared transmittance and hemispherical-directional reflectance data from 2.5 to 25 microm on microstructured silicon surfaces have been measured, and spectral emissivity has been calculated for this wavelength range. Hemispherical-total emissivity is calculated for the samples and found to be 0.84 before a measurement-induced annealing and 0.65 after the measurement for the sulfur-doped sample. Secondary samples lack a measurement-induced anneal, and reasons for this discrepancy are presented. Emissivity numbers are plotted and compared with a silicon substrate, and Aeroglaze Z306 black paint. Use of microstructured silicon as a blackbody or microbolometer surface is modeled and presented, respectively. PMID:20197803

  11. Emission control system

    Science.gov (United States)

    Parrish, Clyde F. (Inventor); Chung, J. Landy (Inventor)

    2009-01-01

    Methods and apparatus utilizing hydrogen peroxide are useful to reduce SOx and mercury (or other heavy metal) emissions from combustion flue gas streams. The methods and apparatus may further be modified to reduce NOx emissions. Continuous concentration of hydrogen peroxide to levels approaching or exceeding propellant-grade hydrogen peroxide facilitates increased system efficiency. In this manner, combustion flue gas streams can be treated for the removal of SOx and heavy metals, while isolating useful by-products streams of sulfuric acid as well as solids for the recovery of the heavy metals. Where removal of NOx emissions is included, nitric acid may also be isolated for use in fertilizer or other industrial applications.

  12. Tomography by positrons emission

    International Nuclear Information System (INIS)

    The tomography by positrons emission is a technology that allows to measure the concentration of positrons emission in a tri dimensional body through external measurements. Among the isotope emissions have carbon isotopes are (11C), of the oxygen (15O), of the nitrogen (13N) that are three the element that constitute the base of the organic chemistry. Theses have on of the PET's most important advantages, since many biological interesting organic molecules can be tracer with these isotopes for the metabolism studies 'in vivo' through PET, without using organic tracers that modify the metabolism. The mentioned isotopes, also possess the characteristic of having short lifetime, that constitute on of PET's advantages from the dosimetric point of view. Among 11C, 15O, and 13N, other isotopes that can be obtained of a generator as the 68Ga and 82Rb

  13. Practical acoustic emission testing

    CERN Document Server

    2016-01-01

    This book is intended for non-destructive testing (NDT) technicians who want to learn practical acoustic emission testing based on level 1 of ISO 9712 (Non-destructive testing – Qualification and certification of personnel) criteria. The essential aspects of ISO/DIS 18436-6 (Condition monitoring and diagnostics of machines – Requirements for training and certification of personnel, Part 6: Acoustic Emission) are explained, and readers can deepen their understanding with the help of practice exercises. This work presents the guiding principles of acoustic emission measurement, signal processing, algorithms for source location, measurement devices, applicability of testing methods, and measurement cases to support not only researchers in this field but also and especially NDT technicians.

  14. Emission tomography: Physical aspects

    International Nuclear Information System (INIS)

    Two different approaches have been followed: i/ tomography by single gamma-photon counting (SPC), using either conventional scintillation cameras or specially designed detector arrays. These systems use radionuclides which are readily available commercially (99 mTc, 131 I, 201 Tl); ii/ positron-emission tomography (ACD) which relies on the simultaneous and colinear emission of two 511 keV gamma photons, permitting a higher detection efficiency and effective 'electronic collimation'. These factors give good spatial resolution and quantitative precision. The principal positron-emitting isotopes 11 C, 13 N, 150 O can also serve as tracers in a very wide range of biological processes. (orig./VJ)

  15. On the Limitations of the Anomalous Microwave Emission Emissivity

    OpenAIRE

    Roberta Paladini; Tibbs, Christopher T.; Clive Dickinson

    2012-01-01

    Many studies of anomalous microwave emission (AME) have computed an AME emissivity to compare the strength of the AME detected in different regions. Such a value is usually defined as the ratio between the intensity of the AME at 1 cm and the thermal dust emission at 100 \\mu m. However, as studies of Galactic dust emission have shown, the intensity of the thermal dust emission at 100 \\mu m is strongly dependent on the dust temperature, which has severe implications for the AME emissivity defi...

  16. Odour emission problem

    International Nuclear Information System (INIS)

    Survey and locating of materials exhaling odours, from a technical point of view, are almost complex. Excellent results have been obtained by CEN in the EN 13725 processing to which every State member of European Union will gear. In Italy, actually, falling directions fixing the limits of odour emissions toward whom causes olfactory nuisances, is applied the article 674 of Penal Code

  17. Acoustic emission source modeling

    Czech Academy of Sciences Publication Activity Database

    Hora, Petr; Červená, Olga

    2010-01-01

    Roč. 4, č. 1 (2010), s. 25-36. ISSN 1802-680X R&D Projects: GA ČR GA101/09/1630 Institutional research plan: CEZ:AV0Z20760514 Keywords : acoustic emission source * wave propagation * FEM Subject RIV: BI - Acoustics

  18. Emissions from urban waste

    International Nuclear Information System (INIS)

    Indiscriminate emission of gases and fumes from improper storage, transport systems and wastes disposals have polluted the environment especially surface and underground water and air. This has irreversibly affects on the environment some of which can be devastating to life.Some of the potential adverse effects on environment include the ozone depletion, acid rain,soil degradation and climate change

  19. Emissions from international shipping

    International Nuclear Information System (INIS)

    The report assesses global emission of ship transport based on fuel consumption, military and civil fleet sizes and average engine statistics. Part 1 gives estimates for the years 1950 to 2001, part 2 displays scenarios for the years 2020 and 2050. (uke)

  20. Reaching peak emissions

    Science.gov (United States)

    Jackson, Robert B.; Canadell, Josep G.; Le Quéré, Corinne; Andrew, Robbie M.; Korsbakken, Jan Ivar; Peters, Glen P.; Nakicenovic, Nebojsa

    2016-01-01

    Rapid growth in global CO2 emissions from fossil fuels and industry ceased in the past two years, despite continued economic growth. Decreased coal use in China was largely responsible, coupled with slower global growth in petroleum and faster growth in renewables.

  1. Positron emission tomography

    International Nuclear Information System (INIS)

    The aim of this project is to provide a simple summary of new trends in positron emission tomography and its basic physical principles. It provides thereby compendious introduction of the trends of the present development in diagnostics using PET systems. A review of available literature was performed. (author)

  2. Automotive Emission Control.

    Science.gov (United States)

    Lee, Billy D.; Ragazzi, Ronald

    This guide designed to assist teachers in improving instruction in the area of automotive emission control curriculum includes four areas. Each area consists of one or more units of instruction, with each instructional unit including some or all of the following basic components: Performance objectives, suggested activities for teacher and…

  3. Diesel emissions in Vienna

    Science.gov (United States)

    Horvath, H.; Kreiner, I.; Norek, C.; Preining, O.; Georgi, B.

    The aerosol in a non-industrial town normally is dominated by emissions from vehicles. Whereas gasoline-powered cars normally only emit a small amount of particulates, the emission by diesel-powered cars is considerable. The aerosol particles produced by diesel engines consist of graphitic carbon (GC) with attached hydrocarbons (HCs) including also polyaromatic HCs. Therefore the diesel particles can be carcinogenic. Besides diesel vehicles, all other combustion processes are also a source for GC; thus source apportionment of diesel emissions to the GC in the town is difficult. A direct apportionment of diesel emissions has been made possible by marking all the diesel fuel used by the vehicles in Vienna by a normally not occurring and easily detectable substance. All emitted diesel particles thus were marked with the tracer and by analyzing the atmospheric samples for the marking substance we found that the mass concentrations of diesel particles in the atmosphere varied between 5 and 23 μg m -3. Busy streets and calm residential areas show less difference in mass concentration than expected. The deposition of diesel particles on the ground has been determined by collecting samples from the road surface. The concentration of the marking substance was below the detection limit before the marking period and a year after the period. During the period when marked diesel fuel was used, the concentrations of the diesel particles settling to the ground was 0.012-0.07 g g -1 of collected dust. A positive correlation between the diesel vehicle density and the sampled mass of diesel vehicles exists. In Vienna we have a background diesel particle concentration of 11 μg m -3. This value increases by 5.5 μg m -3 per 500 diesel vehicles h -1 passing near the sampling location. The mass fraction of diesel particles of the total aerosol mass varied between 12.2 and 33%; the higher values were found in more remote areas, since diesel particles apparently diffuse easily

  4. The Berlin Emissivity Database

    Science.gov (United States)

    Helbert, Jorn

    Remote sensing infrared spectroscopy is the principal field of investigation for planetary surfaces composition. Past, present and future missions to the solar system bodies include in their payload instruments measuring the emerging radiation in the infrared range. TES on Mars Global Surveyor and THEMIS on Mars Odyssey have in many ways changed our views of Mars. The PFS instrument on the ESA Mars Express mission has collected spectra since the beginning of 2004. In spring 2006 the VIRTIS experiment started its operation on the ESA Venus Express mission, allowing for the first time to map the surface of Venus using the 1 µm emission from the surface. The MERTIS spectrometer is included in the payload of the ESA BepiColombo mission to Mercury, scheduled for 2013. For the interpretation of the measured data an emissivity spectral library of planetary analogue materials is needed. The Berlin Emissivity Database (BED) presented here is focused on relatively fine-grained size separates, providing a realistic basis for interpretation of thermal emission spectra of planetary regoliths. The BED is therefore complimentary to existing thermal emission libraries, like the ASU library for example. The BED contains currently entries for plagioclase and potassium feldspars, low Ca and high Ca pyroxenes, olivine, elemental sulphur, common martian analogues (JSC Mars-1, Salten Skov, palagonites, montmorillonite) and a lunar highland soil sample measured in the wavelength range from 3 to 50 µm as a function of particle size. For each sample, the spectra of four well defined particle size separates (¡25 µm , 25-63 µm, 63-125 µm, 125-250 µm) are measured with a 4 cm-1 spectral resolution. These size separates have been selected as typical representations for most of the planetary surfaces. Following an ongoing upgrade of the Planetary Emmissivity Laboratory (PEL) at DLR in Berlin measurements can be obtained at temperatures up to 500° C - realistic for the dayside conditions

  5. Methane emission by camelids.

    Science.gov (United States)

    Dittmann, Marie T; Runge, Ullrich; Lang, Richard A; Moser, Dario; Galeffi, Cordula; Kreuzer, Michael; Clauss, Marcus

    2014-01-01

    Methane emissions from ruminant livestock have been intensively studied in order to reduce contribution to the greenhouse effect. Ruminants were found to produce more enteric methane than other mammalian herbivores. As camelids share some features of their digestive anatomy and physiology with ruminants, it has been proposed that they produce similar amounts of methane per unit of body mass. This is of special relevance for countrywide greenhouse gas budgets of countries that harbor large populations of camelids like Australia. However, hardly any quantitative methane emission measurements have been performed in camelids. In order to fill this gap, we carried out respiration chamber measurements with three camelid species (Vicugna pacos, Lama glama, Camelus bactrianus; n = 16 in total), all kept on a diet consisting of food produced from alfalfa only. The camelids produced less methane expressed on the basis of body mass (0.32±0.11 L kg⁻¹ d⁻¹) when compared to literature data on domestic ruminants fed on roughage diets (0.58±0.16 L kg⁻¹ d⁻¹). However, there was no significant difference between the two suborders when methane emission was expressed on the basis of digestible neutral detergent fiber intake (92.7±33.9 L kg⁻¹ in camelids vs. 86.2±12.1 L kg⁻¹ in ruminants). This implies that the pathways of methanogenesis forming part of the microbial digestion of fiber in the foregut are similar between the groups, and that the lower methane emission of camelids can be explained by their generally lower relative food intake. Our results suggest that the methane emission of Australia's feral camels corresponds only to 1 to 2% of the methane amount produced by the countries' domestic ruminants and that calculations of greenhouse gas budgets of countries with large camelid populations based on equations developed for ruminants are generally overestimating the actual levels. PMID:24718604

  6. Anthropogenic mercury emission inventory with emission factors and total emission in Korea

    Science.gov (United States)

    Kim, Jeong-Hun; Park, Jung-Min; Lee, Sang-Bo; Pudasainee, Deepak; Seo, Yong-Chil

    2010-07-01

    Mercury emissions concentrations, emission factors, and the total national emission from major anthropogenic sources in Korea for the year 2007 were estimated. Uncontrolled and controlled mercury emission factors and the total emission from each source types are presented. The annual national mercury emission from major anthropogenic sources for the year 2007, on average was 12.8 ton which ranged from 6.5 to 20.2 ton. Averaged emissions of elemental, oxidized, and particulate mercury were estimated at 8.25 ton, 3.69 ton, and 0.87 ton, respectively. Due to the removal of a major portion of particulate and oxidized mercury species, elemental mercury was dominant in stack emission. About 54.8% of mercury emission was contributed by industrial sources, 45.0% by stationary combustion sources and 0.02% by mobile sources. Thermal power plants, oil refineries, cement kilns and incinerators (municipal, industrial, medical, sewage sludge) were the major mercury emitters, contributing about 26%, 25%, 21% and 20%, respectively to the total mercury emission. Other sources (crematory, pulp and paper manufacturing, nonferrous metals manufacturing, glass manufacturing) contributed about 8% of the total emission. Priority should be given in controlling mercury emissions from coal-fired power plants, oil refineries, cement kilns and waste incinerators. More measurements including natural and re-emission sources are to be carried out in the future in order to have a clear scenario of mercury emission from the country and to apply effective control measures.

  7. On the Limitations of the Anomalous Microwave Emission Emissivity

    Directory of Open Access Journals (Sweden)

    Christopher T. Tibbs

    2012-01-01

    Full Text Available Many studies of anomalous microwave emission (AME have computed an AME emissivity to compare the strength of the AME detected in different regions. Such a value is usually defined as the ratio between the intensity of the AME at 1 cm and the thermal dust emission at 100 μm. However, as studies of Galactic dust emission have shown, the intensity of the thermal dust emission at 100 μm is strongly dependent on the dust temperature, which has severe implications for the AME emissivity defined in this way. In this work, we illustrate and quantify this effect and find that the AME emissivity decreases by a factor of 11.1 between dust temperatures of 20 and 30 K. We, therefore, conclude that computing the AME emissivity relative to the 100 μm emission does not allow for accurate comparisons between the AME observed in different environments. With this in mind, we investigate the use of other tracers of the dust emission with which to compute the AME emissivity and we ultimately conclude that, despite the difficulty in deriving its value, the column density of the dust would be the most suitable quantity with which to compute the AME emissivity.

  8. Estimating Emissions from Railway Traffic

    DEFF Research Database (Denmark)

    Jørgensen, Morten W.; Sorenson, Spencer C.

    Several parameters of importance for estimating emissions from railway traffic are discussed, and typical results presented. Typical emissions factors from diesel engines and electrical power generation are presented, and the effect of differences in national electrical generation sources...

  9. Estimating Emissions from Railway Traffic

    DEFF Research Database (Denmark)

    Jørgensen, Morten W.; Sorenson, Spencer C.

    1998-01-01

    Several parameters of importance for estimating emissions from railway traffic are discussed, and typical results presented. Typical emissions factors from diesel engines and electrical power generation are presented, and the effect of differences in national electrical generation sources...

  10. Phenomenology of magnetospheric radio emissions

    Science.gov (United States)

    Carr, T. D.; Desch, M. D.; Alexander, J. K.

    1983-01-01

    Jupiter has now been observed over 24 octaves of the radio spectrum, from about 0.01 MHz to 300,000 MHz. Its radio emissions fill the entire spectral region where interplanetary electromagnetic propagation is possible at wavelengths longer than infrared. Three distinct types of radiation are responsible for this radio spectrum. Thermal emission from the atmosphere accounts for virtually all the radiation at the high frequency end. Synchrotron emission from the trapped high-energy particle belt deep within the inner magnetosphere is the dominant spectral component from about 4000 to 40 MHz. The third class of radiation consists of several distinct components of sporadic low frequency emission below 40 MHz. The decimeter wavelength emission is considered, taking into account the discovery of synchrotron emission, radiation by high-energy electrons in a magnetic field, and the present status of Jovian synchrotron phenomenology. Attention is also given to the decameter and hectometer wavelength emission, and emissions at kilometric wavelengths.

  11. Global emissions inventories

    Energy Technology Data Exchange (ETDEWEB)

    Dignon, J.

    1995-07-01

    Atmospheric chemistry determines the concentrations of most of the important greenhouse gases except for carbon dioxide. The rate of removal of the greenhouse gases from the atmosphere is also controlled by atmospheric chemistry. The indirect effects of chemical forcing resulting from the chemical interactions of other species can also affect the concentrations of radiatively important gases such as ozone. In order to establish the contribution of any possible climatic change attributable to individual greenhouse gases, spatially and temporally resolved estimates of their emissions need to be established. Unfortunately, for most of the radiatively important species the global magnitudes of their individual fluxes are not known to better than a factor of two and their spatial distributions are even more poorly characterized. Efforts to estimate future projections of potential impacts and to monitor international agreements will require continued research to narrow the uncertainties of magnitude and geographical distribution of emissions.

  12. Positron emission tomography.

    Science.gov (United States)

    Hoffman, E J; Phelps, M E

    1979-01-01

    Conventional nuclear imaging techniques utilizing lead collimation rely on radioactive tracers with little role in human physiology. The principles of imaging based on coincidence detection of the annihilation radiation produced in positron decay indicate that this mode of detection is uniquely suited for use in emission computed tomography. The only gamma-ray-emitting isotopes of carbon, nitrogen, and oxygen are positron emitters, which yield energies too high for conventional imaging techniques. Thus development of positron emitters in nuclear medicine imaging would make possible the use of a new class of physiologically active, positron-emitting radiopharmaceuticals. The application of these principles is described in the use of a physiologically active compound labeled with a positron emitter and positron-emission computed tomography to measure the local cerebral metabolic rate in humans. PMID:440173

  13. Global emissions inventories

    International Nuclear Information System (INIS)

    Atmospheric chemistry determines the concentrations of most of the important greenhouse gases except for carbon dioxide. The rate of removal of the greenhouse gases from the atmosphere is also controlled by atmospheric chemistry. The indirect effects of chemical forcing resulting from the chemical interactions of other species can also affect the concentrations of radiatively important gases such as ozone. In order to establish the contribution of any possible climatic change attributable to individual greenhouse gases, spatially and temporally resolved estimates of their emissions need to be established. Unfortunately, for most of the radiatively important species the global magnitudes of their individual fluxes are not known to better than a factor of two and their spatial distributions are even more poorly characterized. Efforts to estimate future projections of potential impacts and to monitor international agreements will require continued research to narrow the uncertainties of magnitude and geographical distribution of emissions

  14. Danish emission inventories for agriculture

    DEFF Research Database (Denmark)

    Mikkelsen, Mette Hjorth; Albrektsen, Rikke; Gyldenkærne, Steen

    By regulations given in international conventions Denmark is obliged to work out an annual emission inventory and document the methodology. The National Environmental Research Institute (NERI) at Aarhus University (AU) in Denmark is responsible for calculating and reporting the emissions. This re......By regulations given in international conventions Denmark is obliged to work out an annual emission inventory and document the methodology. The National Environmental Research Institute (NERI) at Aarhus University (AU) in Denmark is responsible for calculating and reporting the emissions...

  15. Field Emission in Vacuum Microelectronics

    CERN Document Server

    Fursey, George; Schwoebel, Paul

    2005-01-01

    Field emission is a phenomenon described by quantum mechanics. Its emission capability is millions times higher than that of any other known types of electron emission. Nowadays this phenomenon is experiencing a new life due to wonderful applications in the atomic resolution microscopy, in electronic holography, and in the vacuum micro- and nanoelectronics in general. The main field emission properties, and some most remarkable experimental facts and applications, are described in this book.

  16. Acoustic emission source modeling

    Czech Academy of Sciences Publication Activity Database

    Hora, Petr; Červená, Olga

    Plzeň : University of West Bohemia, 2009 - (Adámek, V.; Zajíček, M.). s. 1-2 ISBN 978-80-7043-824-4. [Výpočtová mechanika 2009. 09.11.2009-11.11.2009, Nečtiny] R&D Projects: GA ČR GA101/09/1630 Institutional research plan: CEZ:AV0Z20760514 Keywords : acoustic emission source * wave propagation * FEM Subject RIV: BI - Acoustics

  17. Acoustic emission source modeling

    Directory of Open Access Journals (Sweden)

    Hora P.

    2010-07-01

    Full Text Available The paper deals with the acoustic emission (AE source modeling by means of FEM system COMSOL Multiphysics. The following types of sources are used: the spatially concentrated force and the double forces (dipole. The pulse excitation is studied in both cases. As a material is used steel. The computed displacements are compared with the exact analytical solution of point sources under consideration.

  18. Zero emissions trucks

    OpenAIRE

    Eelco, den Boer; Aarnink, Sanne; Kleiner, Florian; Pagenkopf, Johannes

    2013-01-01

    Battery-electric and fuel-cell trucks could be feasible in Europe within little more than a decade, concludes this study commissioned by the International Council on Clean Transportation (ICCT), and taking the steps necessary to turn that possibility into reality is crucial to meeting long-term climate goals in the transport sector. Road freight is one of the fastest-growing contributors to CO2 emissions of the European transport sector. That trend must be reversed if the European Uni...

  19. Power plant emissions reduction

    Science.gov (United States)

    Anand, Ashok Kumar; Nagarjuna Reddy, Thirumala Reddy

    2015-10-20

    A system for improved emissions performance of a power plant generally includes an exhaust gas recirculation system having an exhaust gas compressor disposed downstream from the combustor, a condensation collection system at least partially disposed upstream from the exhaust gas compressor, and a mixing chamber in fluid communication with the exhaust gas compressor and the condensation collection system, where the mixing chamber is in fluid communication with the combustor.

  20. Positron-emission tomography

    International Nuclear Information System (INIS)

    Positron-emission tomography (PET) combines early biochemical assessment of pathology achieved by nuclear medicine with the precise localization achieved by computerized image reconstruction. In this technique a chemical compound with the desired biological activity is labeled with a radioactive isotope that decays by emitting a positron, or positive electron. With suitable interpretation PET images can provide a noninvasive, regional assessment of many biochemical processes that are essential to the functioning of the organ that is being visualized

  1. Aircrafts' taxi noise emission

    OpenAIRE

    Asensio Rivera, César; Pagán Muñoz, Raúl; López Navarro, Juan Manuel

    2008-01-01

    During planning stages, when noisy activity has not been implanted or while evaluating operation changes, it is necessary to find an environmental noise mapping prediction tool for future scenarios. When an activity is already implanted, it is possible to measure noise emissions, but this is expensive, so prediction tools can also be useful. Because of these reasons, for the last 10 years, as a response to the increasing concern for noise pollution in developed countries, several simulation m...

  2. Emission inventory for fugitive emissions from fuel in Denmark

    DEFF Research Database (Denmark)

    Plejdrup, Marlene Schmidt; Nielsen, Ole-Kenneth; Nielsen, Malene

    This report presents the methodology and data used in the Danish inventory of fugitive emissions from fuels for the years until 2013. The inventory of fugitive emissions includes CO2, CH4, N2O, SO2, NOx, NMVOC, CO, particulate matter, Black carbon, heavy metals, dioxin and PAHs. In 2013 the total...... Danish emission of greenhouse gasses was 54 584 Gg CO2 equivalents. Fugitive emissions from fuels account for 387 Gg CO2 equivalents or approximately 1 %. The major part of the fugitive emissions are emitted as CO2 (61 %) mainly from flaring in upstream oil and gas production. The major source of...

  3. Emission trading: A discussion paper

    International Nuclear Information System (INIS)

    Emission trading is a market-based incentive program designed to control air emissions in which a cap is placed on the total quantity of pollutants allowed to be emitted in an airshed. Appropriate shares of this amount are allocated among participating emission sources, and participants can buy or sell their shares. Advantages of emission trading include its potential to achieve air emission targets at a lower cost than the traditional command and control approach, and its ability to accommodate economic growth without compromising environmental quality. A study was conducted to evaluate the potential use of emission trading programs to achieve emission reduction goals set for nitrogen oxides, volatile organic compounds (VOC), and sulfur oxides. Emission trading programs in the USA are reviewed and a set of factors important for the success of emission trading are identified. Key policy and design issues related to an emission trading program are identified, explained, and discussed. Administrative issues are then analyzed, such as legislative authority, monitoring and enforcement requirements, and trading between jurisdictions. A preliminary assessment of emission trading for control of NOx and VOC in the Lower Fraser Valley indicates that emission trading would be feasible, but legislative authority to implement such a program would have to be introduced

  4. Field emission in RF cavities

    International Nuclear Information System (INIS)

    Electron field emission limits the accelerating gradient in superconducting cavities. It is shown how and why it is an important problem. The phenomenology of field emission is then described, both in DC and RF regimes. Merits of a few plausible 'remedies' to field emission are discussed. (author)

  5. THz wave emission microscope

    Science.gov (United States)

    Yuan, Tao

    Sensing and imaging using Terahertz (THz) radiation has attracted more and more interest in the last two decades thanks to the abundant material 'finger prints' in the THz frequency range. The low photon energy also makes THz radiation an attractive tool for nondestructive evaluation of materials and devices, biomedical applications, security checks and explosive screening. Due to the long wavelength, the far-field THz wave optical systems have relatively low spatial resolution. This physical limitation confines THz wave sensing and imaging to mostly macro-size samples. To investigate local material properties or micro-size structures and devices, near-field technology has to be employed. In this dissertation, the Electro-Optical THz wave emission microscope is investigated. The basic principle is to focus the femtosecond laser to a tight spot on a thin THz emitter layer to produce a THz wave source with a similar size as the focus spot. The apparatus provides a method for placing a THz source with sub-wavelength dimension in the near-field range of the investigated sample. Spatial resolution to the order of one tenth of the THz wavelength is demonstrated by this method. The properties of some widely used THz wave emission materials under tight focused pump light are studied. As an important branch of THz time domain spectroscopy (THz-TDS), THz wave emission spectroscopy has been widely used as a tool to investigate the material physics, such as energy band structure, carrier dynamics, material nonlinear properties and dynamics. As the main work of this dissertation, we propose to combine the THz wave emission spectroscopy with scanning probe microscopy (SPM) to build a tip-assisted THz wave emission microscope (TATEM), which is a valuable extension to current SPM science and technology. Illuminated by a femtosecond laser, the biased SPM tip forms a THz wave source inside the sample beneath the tip. The source size is proportional to the apex size of the tip so

  6. Positron emission tomography

    CERN Document Server

    Paans, A M J

    2006-01-01

    Positron Emission Tomography (PET) is a method for measuring biochemical and physiological processes in vivo in a quantitative way by using radiopharmaceuticals labelled with positron emitting radionuclides such as 11C, 13N, 15O and 18F and by measuring the annihilation radiation using a coincidence technique. This includes also the measurement of the pharmacokinetics of labelled drugs and the measurement of the effects of drugs on metabolism. Also deviations of normal metabolism can be measured and insight into biological processes responsible for diseases can be obtained. At present the combined PET/CT scanner is the most frequently used scanner for whole-body scanning in the field of oncology.

  7. Infrared emission from novae

    CERN Document Server

    Evans, A

    2012-01-01

    We review infrared observations of classical and recurrent novae, at wavelengths >3microns, including both broad-band and spectroscopic observations. In recent years infrared spectroscopy in particular has revolutionised our understanding of the nova phenomenon, by revealing fine-structure and coronal lines, and the mineralogy of nova dust. Infrared spectroscopic facilities that are, or will be, becoming available in the next 10 - 20 years have the potential for a comprehensive study of nova line emission and dust mineralogy, and for an unbiassed assessment of the extragalactic nova populations.

  8. Positron Emission Tomography (PET)

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET. 22 figs

  9. Emissivity compensated spectral pyrometry for varying emissivity metallic measurands

    International Nuclear Information System (INIS)

    A novel method for converting electromagnetic spectral radiance information into temperature measurements is presented. It allows for varying spectral emissivity of the metallic measurand during the course of the measurement. Such variations are due to, e.g., thermal oxidation or temperature dependent emissivity. Based on a requirement that emissivity changes with time and temperature are smooth, it is assumed that an emissivity estimate at one sample instance can be derived from the estimated emissivity found at the previous samples together with updated spectral information. This leads to successive recalculations of spectral emissivity together with corresponding temperature values. The proposed algorithm has been proven to give accurate temperature estimates from a measurement based on the data captured by a standard UV-Vis spectrophotometer even for an oxidizing Ti-6Al-4V specimen in a temperature range between 900 and 1400 K. The method however, is not limited to these wavelength or temperature ranges. (paper)

  10. Spinning dust emission from ultrasmall silicates: emissivity and polarization spectrum

    CERN Document Server

    Hoang, Thiem; Lan, Nguyen Quynh

    2016-01-01

    Anomalous microwave emission (AME) is an important Galactic foreground of Cosmic Microwave Background (CMB) radiation. It is believed that the AME arises from rotational emission by spinning polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM). In this paper, we assume that a population of ultrasmall silicate grains may exist in the ISM, and quantify rotational emissivity from these tiny particles and its polarization spectrum. We found that spinning silicate nanoparticles can produce strong rotational emission when those small grains follow a log-normal size distribution. The polarization fraction of spinning dust emission from tiny silicates increases with decreasing the dipole moment per atom ($\\beta$) and can reach $P\\sim 20\\%$ for $\\beta\\sim 0.1$D at grain temperature of 60 K. We identify a parameter space $(\\beta,Y_{Si})$ for silicate nanoparticles in which its rotational emission can adequately reproduce both the observed AME and the polarization of the AME, without violating the ob...

  11. For sale: Sulfur emissions

    International Nuclear Information System (INIS)

    The allowance trading market has started a slow march to maturity. Competitive developers should understand the risks and opportunities now presented. The marketplace for sulfur dioxide (SO2) emissions allowances - the centerpiece of Title 4's acid rain reduction program - remains enigmatic 19 months after the Clean Air Act amendments of 1990 were passed. Yet it is increasingly clear that the emission allowance market will likely confound the gloom and doom of its doubters. The recently-announced $10 million dollar Wisconsin Power and Light allowance sales to Duquesne Light and the Tennessee Valley Authority are among the latest indications of momentum toward a stabilizing market. This trend puts additional pressure on independent developers to finalize their allowance strategies. Developers who understand what the allowance trading program is and what it is not, know the key players, and grasp the unresolved regulatory issues will have a new competitive advantage. The topics addressed in this article include the allowance marketplace, marketplace characteristics, the regulatory front, forward-looking strategies, and increasing marketplace activity

  12. Zero emission coal

    Energy Technology Data Exchange (ETDEWEB)

    Ziock, H.; Lackner, K.

    2000-08-01

    We discuss a novel, emission-free process for producing hydrogen or electricity from coal. Even though we focus on coal, the basic design is compatible with any carbonaceous fuel. The process uses cyclical carbonation of calcium oxide to promote the production of hydrogen from carbon and water. The carbonation of the calcium oxide removes carbon dioxide from the reaction products and provides the additional energy necessary to complete hydrogen production without additional combustion of carbon. The calcination of the resulting calcium carbonate is accomplished using the high temperature waste heat from solid oxide fuel cells (SOFC), which generate electricity from hydrogen fuel. Converting waste heat back to useful chemical energy allows the process to achieve very high conversion efficiency from fuel energy to electrical energy. As the process is essentially closed-loop, the process is able to achieve zero emissions if the concentrated exhaust stream of CO{sub 2} is sequestered. Carbon dioxide disposal is accomplished by the production of magnesium carbonate from ultramafic rock. The end products of the sequestration process are stable naturally occurring minerals. Sufficient rich ultramafic deposits exist to easily handle all the world's coal.

  13. Positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) is a method for quantitative imaging of regional physiological and biochemical parameters. Positron emitting radioactive isotopes can be produced by a cyclotron, eg. the biologically important carbon (11C), oxygen (15O), and nitrogen (13N) elements. With the tomographic principles of the PET scanner the quantitative distribution of the administered isotopes can be determined and images can be provided as well as dynamic information on blood flow, metabolism and receptor function. In neurology PET has been used for investigations on numerous physiological processes in the brain: circulation, metabolism and receptor studies. In Parkinson's disease PET studies have been able to localize the pathology specifically, and in early stroke PET technique can outline focal areas with living but non-functioning cells, and this could make it possible to intervene in this early state. With positron emission tomography a quantitative evaluation of myocardial blood flow, glucose and fatty acid metabolism can be made as well as combined assessments of blood flow and metabolism. Combined studies of blood flow and metabolism can determine whether myocardial segments with abnormal motility consist of necrotic or viable tissue, thereby delineating effects of revascularisation. In the future it will probably be possible to characterize the myocardial receptor status in different cardiac diseases. The PET technique is used in oncology for clinical as well as more basic research on tumor perfusion and metabolism. Further, tumor uptake of positron labelled cytotoxic drugs might predict the clinical benefit of treatment. (au) (19 refs.)

  14. Emission from ferroelectric cathodes

    International Nuclear Information System (INIS)

    The authors have recently initiated an investigation of electron emission from ferroelectric cathodes. The experimental apparatus consisted of an electron diode and a 250 kV, 12 ohm, 70 ns pulsed high voltage power source. A planar triode modulator driven by a synthesized waveform generator initiates the polarization inversion and allows inversion pulse tailoring. The pulsed high voltage power source is capable of delivering two high voltage pulses within 50 μs of each other and is capable of operating at a sustained repetition rate of 5 Hz. The initial measurements indicate that emission current densities above the Child-Langmuir Space Charge Limit, JCL, are possible. They explain this effect to be based on a non-zero initial energy of the emitted electrons. They also determined that this effect is strongly coupled to relative timing between the inversion pulse and application of the main anode-cathode pulse. They also have initiated brightness measurements of the emitted beam and estimate a preliminary lower bound to be on the order of 109 A/m2-rad2 for currents close to JCL and factor of two less at currents over 4JCL. As in previous measurements at this Laboratory, they performed the measurement using a pepper pot technique. Beamlet profiles are recorded with a fast phosphor and gated cameras. They describe their apparatus and preliminary measurements

  15. 40 CFR 61.122 - Emission standard.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Emission standard. 61.122 Section 61...) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standards for Radionuclide Emissions From Elemental Phosphorus Plants § 61.122 Emission standard. Emissions of polonium-210 to...

  16. Emission to air in Norway. Emission sources and trends

    International Nuclear Information System (INIS)

    The report gives an overview of Norwegian emissions that may contribute to global climatic changes, regional acidification problems and local air pollution problems. Included in these emissions are carbon dioxide, methane, dinitrous oxide, sulfur dioxide, nitrogen oxides, volatile organic compounds, ammonia, carbon monoxide, particulates and lead. Detailed figures are given for 1991 as well as a description of the development in the period 1973-1992. The development of the amount of emissions is compared with existing international agreement and national goals

  17. Spinning dust emission from ultrasmall silicates: emissivity and polarization spectrum

    OpenAIRE

    Hoang, Thiem; Vinh, Nguyen Anh; Lan, Nguyen Quynh

    2016-01-01

    Anomalous microwave emission (AME) is an important Galactic foreground of Cosmic Microwave Background (CMB) radiation. It is believed that the AME arises from rotational emission by spinning polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM). In this paper, we assume that a population of ultrasmall silicate grains may exist in the ISM, and quantify rotational emissivity from these tiny particles and its polarization spectrum. We found that spinning silicate nanoparticles...

  18. GHG emissions due to deforestation

    International Nuclear Information System (INIS)

    An assessment was made for the magnitude of greenhouse gas emissions resulting from deforestation and forest degradation in tropical forests in Malaysia and Indonesia related to Dutch economic activities. Greenhouse gas emissions (GHG) are calculated in relation to (1) the emissions related to vegetation removal sec; and (2) the emissions related to removal and more long term effects related to assimilation of CO2 in forest regrowth and changes in organic material in soils. Emissions related to vegetation removal and aggregated emissions for both vegetation removal and long term effects are reported separately. Soil organic carbon stock changes are considered by Greenpeace as more uncertain, so the emphasis will be on the direct emissions. Changes in carbon stocks and N2O emissions and actually also changes in vegetation all are events that occur gradually, rather than immediately. Only removal of existing vegetation and possible burning of this vegetation and associated emissions related to both activities are immediate by nature. Carbon stocks and N2O emissions change to a new level within several decades after deforestation or forest degradation. Removed vegetation can grow back or be replaced eventually by other vegetation, thereby changing the net greenhouse gas (GHG) emissions related to deforestation or forest degradation. Vegetation extracted for commercial purposes such as timber or pulp will also take years or decades to become waste and be converted into CO2. In IPCC and LCA's all these emissions are taken into account - or at least all emissions occurring within a period of 20 years, as required by IPCC. Soil organic carbon stock changes are also considered by Greenpeace as more uncertain, so the emphasis will be on the direct emmissions.

  19. AGN Coronal Emission models I. The Predicted Radio Emission

    CERN Document Server

    Raginski, Igor

    2016-01-01

    Accretion discs in AGN may be associated with coronal gas, as suggested by their X-ray emission. Stellar coronal emission includes radio emission, and AGN corona may also be a significant source for radio emission in radio quiet (RQ) AGN. We calculate the coronal properties required to produce the observed radio emission in RQ AGN, either from synchrotron emission of power-law (PL) electrons, or from cyclo-synchrotron emission of hot mildly-relativistic thermal electrons. We find that a flat spectrum, as observed in about half of RQ AGN, can be produced by corona with a disc or a spherical configuration, which extends from the innermost regions out to a pc scale. A spectral break to an optically thin power-law emission is expected around 300-1000 GHz, as the innermost corona becomes optically thin. In case of thermal electrons, a sharp spectral cutoff is expected above the break. The position of the break can be measured with VLBI observations, which exclude the cold dust emission, and it can be used to probe...

  20. Neutrino Emissivity of Dense Stars

    OpenAIRE

    Ghosh, Sanjay K.; Phatak, S. C.; P.K. Sahu

    1995-01-01

    The neutrino emissivity of compact stars is investigated in this work. We consider stars consisting of nuclear as well as quark matter for this purpose. Different models are used to calculate the composition of nuclear and quark matter and the neutrino emissivity. Depending on the model under consideration, the neutrino emissivity of nuclear as well as quark matter varies over a wide range. We find that for nuclear matter, the direct URCA processes are allowed for most of the relativistic mod...

  1. Fraud risks in emissions trading

    International Nuclear Information System (INIS)

    The system of emission trading is a complex composed entity with on the one hand a strong environmental component and on the other hand a financial world that hooked on this instrument. In chapter 2 an introduction is provided to the emission trading system. The subsequent chapters elaborate Types of Fraud (Chapter 3), Powers (Chapter 4), and Instruments (Chapter 5). The report shows that various forms of fraud are occurring in emission trading, such as VAT fraud and identity theft.

  2. Emissions from small heating plants

    International Nuclear Information System (INIS)

    This study treats emissions from and economy of small biofuelled heating plants. In order to reduce emissions of particulates below 100 mg/nm3, the plants must be equipped with flue gas cleaning systems superior to cyclones/multicyclones. The use of pellets or pulverized fuel does not necessarily give emissions lower than 100 mg/nm3. However, the study shows that the CO-emissions can be kept low. An economic analysis for biofuelled plants is also presented 18 tabs, 18 figs

  3. Gaseous emissions from coal stockpiles

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-01-15

    Stockpiled coal undergoes atmospheric oxidation and desorption processes during open air storage. These processes release gases to the environment which may effect health and safety by their toxicity and flammability. In extreme cases, this could lead to a fire. This report discusses gaseous emissions from coal stockpiles. It covers gas emission mechanisms, and gas sampling and testing methods, before examining in more detail the principal gases that have been emitted. It concludes that there is limited research in this area and more data are needed to evaluate the risks of gaseous emissions. Some methods used to prevent coal self-heating and spontaneous combustion can be applied to reduce emissions from coal stockpiles.

  4. The Emissions Gap Report 2014

    DEFF Research Database (Denmark)

    This fifth Emissions Gap report has a different focus from previous years. While it updates the 2020 emissions gap analysis, it gives particular attention to the implications of the global carbon dioxide emissions budget for staying within the 2 °C limit beyond 2020. It does so because countries...... are giving increasing attention to where they need to be in 2025, 2030 and beyond. Furthermore, this year’s update of the report benefits from the findings on the emissions budget from the latest series of Intergovernmental Panel on Climate Change (IPCC) reports...

  5. Carbon emissions and income inequality

    International Nuclear Information System (INIS)

    We find that the distribution of income matters to aggregate carbon dioxide emissions and hence global warming. Higher inequality, both between and within countries is associated with lower carbon emissions at given average incomes. We also confirm that economic growth generally comes with higher emissions. Thus our results suggest that trade-offs exist between climate control (on the one hand) and both social equity and economic growth (on the other). However, economic growth improves the trade off with equity, and lower inequality improves the trade off with growth. By combining growth with equity, more pro-poor growth processes yield better longer-term trajectories of carbon emissions. (Author)

  6. OPIC Greenhouse Gas Emissions Inventory

    Data.gov (United States)

    Overseas Private Investment Corporation — Independent analysis details quantifying the greenhouse gas ("GHG") emissions directly attributable to projects to which the Overseas Private Investment Corporation...

  7. Positron emission mammography imaging

    Energy Technology Data Exchange (ETDEWEB)

    Moses, William W.

    2003-10-02

    This paper examines current trends in Positron Emission Mammography (PEM) instrumentation and the performance tradeoffs inherent in them. The most common geometry is a pair of parallel planes of detector modules. They subtend a larger solid angle around the breast than conventional PET cameras, and so have both higher efficiency and lower cost. Extensions to this geometry include encircling the breast, measuring the depth of interaction (DOI), and dual-modality imaging (PEM and x-ray mammography, as well as PEM and x-ray guided biopsy). The ultimate utility of PEM may not be decided by instrument performance, but by biological and medical factors, such as the patient to patient variation in radiotracer uptake or the as yet undetermined role of PEM in breast cancer diagnosis and treatment.

  8. Radio emission from novae

    International Nuclear Information System (INIS)

    The nature and measurement of radio emission from novae is discussed. The classical novae for which there are reported measurements of radio flux densities are listed. The three which have been studied most extensively are the slow nova HR Delta, the moderate speed nova FH Ser and the fast nova V1500 Cyg. Two different types of models have been used to model classical novae, the variable speed model and a Hubble flow model. V1500 Cyg has been observed in both radio and infrared spectra. The behaviour which explains this is discussed. Estimates of distance shell, mass and kinetic energy have been made from the data. Radioemissions from related objects and nova remnants are also discussed. (U.K.)

  9. Positon Emission Tomography sampling

    International Nuclear Information System (INIS)

    This work deals with the study of data acquisition in Positon Emission Tomography (PET). Its aim is to optimize the quantity of data measured compared with the maximum spatial resolution it is possible to reach on a reconstructed image. One of the contribution in this field is to determine the efficiency of rectangular detectors compared with the square ones. In the second part of this thesis is studied the performances of a PET scanner for the small animal imagery. The originality of this scanner is the use of liquid xenon as scintillating medium and the ability to measure the interaction depth. A Monte Carlo simulation chain of this scanner has been carried out, compared and validated with the experimental results. (O.M.)

  10. Emission tomography system

    International Nuclear Information System (INIS)

    In the present invention a positron emission tomographic system is provided in which the random photon coincidence background is determined for the lines of sight along which the positron annihiliations are located. The circuitry is arranged so that this background may be subtracted almost simultaneously from the total photon coincidence measurement, or may be stored in a temporary memory for latter subtraction. In this system, an appropriate coincidence resolution time is selected and coincidences of photons detected at 180 degree opposed detectors within the time resolution are recorded as the overall coincidence count. This total count includes a source(true events) count plus a background(random coincidences) count. The background count is determined by measuring photons detected at these same sets of photon detectors and employing the same coincidence resolution period, where the signals from one set of detectors are passed through a delay longer in time than this resolution period

  11. Fission neutron statistical emission

    International Nuclear Information System (INIS)

    The statistical model approach FINESSE (FIssion NEutronS' Statistical Emission) for the description of fission neutron multiplicities, energy spectra and angular distributions is described. Based on an extended Weisskopf ansatz and on a realistic temperature distribution it provides a fragment mass number dependent description of fission neutron data. Model parameters (optical potential, n/γ competition) were fixed on the basis of the 252Cf(sf) (nuclear data standard). Combined with a phenomenological fission model for predicting relevant fragment data as function of asymmetry. FINESSE can be applied to any fission reaction of actinides in the Th-Cf region without further parameter adjustment. Results are presented for 252Cf(sf) and neutron induced fission of 235U, 239Pu, 232Th. Effects of multiple-chance fission are discussed for 232Th(n,xnf) reacation. (author). 46 refs, 11 figs

  12. Acoustic emission testing

    CERN Document Server

    Grosse, Christian U

    2008-01-01

    Acoustic Emission (AE) techniques have been studied in civil engineering for a long time. The techniques are recently going to be more and more applied to practical applications and to be standardized in the codes. This is because the increase of aging structures and disastrous damages due to recent earthquakes urgently demand for maintenance and retrofit of civil structures in service for example. It results in the need for the development of advanced and effective inspection techniques. Thus, AE techniques draw a great attention to diagnostic applications and in material testing. The book covers all levels from the description of AE basics for AE beginners (level of a student) to sophisticated AE algorithms and applications to real large-scale structures as well as the observation of the cracking process in laboratory specimen to study fracture processes.

  13. Thermoluminescence emission spectrometer.

    Science.gov (United States)

    Prescott, J R; Fox, P J; Akber, R A; Jensen, H E

    1988-08-15

    A sensitive thermoluminescence (TL) emission spectrometer based on Fourier transform spectroscopy is described. It employs a modified scanning Twyman-Green interferometer with photomultiplier detection in a photon-counting mode. The etendue is 180pi mm(2), and it covers the 350-600-nm wavelength range. The output can be displayed either as a 3-D isometric plot of intensity vs temperature and wavelength, as a contour diagram, or as a conventional TL glow curve of intensity vs temperature. It is sufficiently sensitive to record thermoluminescence spectra of dosimeter phosphors and minerals for thermoluminescence dating at levels corresponding to those found during actual use as radiation monitors or in dating. Examples of actual spectra are given. PMID:20539405

  14. Emission computed tomography

    International Nuclear Information System (INIS)

    Although there are many common aspects to x-ray transmission and radionuclide emission (ECT) computerized tomography, there are added difficulties and a number of particular factors which form the basis of ECT. The relationship between the physical factors, system design, methodologic approach and assumptions of ECT is discussed. The instrumentation design and application strategies in ECT at this time are diverse and in a rapid stage of development. The approaches are divided into two major categories of Single Photon Counting (SPC) employing scanner and camera concepts with radionuclides of 99/sup m/Tc, 201Tl, 123I etc., and Annihilation Coincidence Detection (ACD) of positron-emitting radionuclides. Six systems in the former and ten systems in the latter category, with examples of typical studies, illustrate the different approaches

  15. Selfcalibrating secondary emission quantometer

    International Nuclear Information System (INIS)

    Self-calibrating secondary emission quantometer (SEQ), providing the monitoring parameters of powerfull pulse beam of bremsstrahlung is described. SEQ is composed of an assembly of emitter and collector sheet-electrodes, in which collector sheets are isolated. Each collector sheet is connected through commutator with measuring device, thermometer, heating element and cooling jacket, isolated one from another and connected through commutator with measuring device are installed in each emitter sheet. Simultaneous measuring and comparison of sum signals from all thermometers and all collector sheets is equivalent to absolute calibration of SEQ. SEQ enables to determine during one run the apparent beam energy and measurement of bremsstrahlung spectrum. The prototype of self-calibrating SEQ, having sensitivity, stable in the limits of +-1% in 100 - 103 MeV energy range and 10-5 - 103 Wxsm-2 beam power range is under development

  16. Seismic Resonant Emission

    Science.gov (United States)

    Korneev, V. A.

    2007-12-01

    There are several classes of underground objects which can produce resonant emission after being hit by incident seismic waves. Those objects include tunnels, pipes, buried containers, ground-filled excavations, unexploded ordinances, fluid-filled fractures, mine shafts, and the like. Being high contrast scatterers, these objects are capable of generating strong scattered waves where primary PP, PS, SS waves carry away most of the energy which was brought by incident waves. For both high- and low- velocity objects the primary scattered waves have the same order of magnitude as incident waves. The main difference between these groups of objects is in later arrivals of multiple scattered waves. While high-velocity objects effectively radiate most of the energy soon after impact, the low-velocity objects trap some fraction of incident wave energy in the form of circumferential waves which propagate rotating along the interface between the object and the embedding medium. Circumferential waves include surface Rayleigh-type waves (propagating mostly in the embedding medium), Stoneley waves (propagating mostly in the fluid, if present), and Frantz waves (body waves trapped in the object because of its curvature). Strong impedance contrast ensures small radiation loss for circumferential waves and they slowly decay in amplitude while rotating inside/around the object. Some circumferential waves exist in the high-velocity objects but their amplitudes decay very fast because of strong radiation in outer medium. Most of the secondary (multiply reflected from an object's boundaries or multiply circled around the object) resonant-scattered energy radiates in the embedding medium as shear waves. The possibility of neglecting P- waves in late scattering arrivals simplifies imaging as is demonstrated for the field and modeled data of the example. Resonant emission phenomenon provides an effective tool for active monitoring for a number of applications such as tunnel detection

  17. Emissivity of condensed phases from the spontaneous emission spectrum

    International Nuclear Information System (INIS)

    The method of determining the temperature and spectral emissivity of substances unavailable for direct contact is described. Potentialities of the method were demonstrated using incandescent lamps with emitting filaments made of tungsten, rhenium and tantalum. Accuracy of determination of the temperature and spectral emissivity (in the range of spectrum 0.9-2.1 μm) made up 1 and 10% respectively

  18. Estimation of broadband surface emissivity from narrowband emissivities.

    Science.gov (United States)

    Tang, Bo-Hui; Wu, Hua; Li, Chuanrong; Li, Zhao-Liang

    2011-01-01

    This work analyzed and addressed the estimate of the broadband emissivities for the spectral domains 3-14μm (ε(3-14)) and 3-∞μm (ε(3-∞). Two linear narrow-to-broadband conversion models were proposed to estimate broadband emissivities ε(3-14) and ε(3-∞) using the Moderate Resolution Imaging Spectroradiometer (MODIS) derived emissivities in three thermal infrared channels 29 (8.4-8.7μm), 31 (10.78-11.28μm) and 32 (11.77-12.27μm). Two independent spectral libraries, the Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) spectral library and the MODIS UCSB (University of California, Santa Barbara) emissivity library, were used to calibrate and validate the proposed models. Comparisons of the estimated broadband emissivities using the proposed models and the calculated values from the spectral libraries, showed that the proposed method of estimation of broadband emissivity has potential accuracy and the Root Mean Square Error (RMSE) between estimated and calculated broadband emissivities is less than 0.01 for both ε(3-14) and ε(3-∞). PMID:21263556

  19. Emissivity measurement of high-emissivity black paint at CENAM

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas G, D., E-mail: dcardena@cenam.mx [Centro Nacional de Metrologia, Km 4.5 Carretera a los Cues, El Marques, 76246 Santiago de Queretaro, Queretaro (Mexico)

    2014-07-01

    To measure the temperature of the surface of an opaque object by radiation thermometry, it is necessary to know its surface emissivity. High emissivity black paint can be applied to the inner walls of a cavity to be used as a blackbody radiator. It can also be applied to some highly reflecting metals so that their temperature can be estimated by radiation thermometry. In this work, it is described the emissivity measurement of high-emissivity black paint that has been used for the two applications described above. The average emissivity of the measured paint in the 8 to 14 micrometers wavelength range was estimated as 0.972 ± 0.012. The results obtained may be of use for those using the paint at temperatures from 50 to 150 grades C. (Author)

  20. Emissivity measurement of high-emissivity black paint at CENAM

    International Nuclear Information System (INIS)

    To measure the temperature of the surface of an opaque object by radiation thermometry, it is necessary to know its surface emissivity. High emissivity black paint can be applied to the inner walls of a cavity to be used as a blackbody radiator. It can also be applied to some highly reflecting metals so that their temperature can be estimated by radiation thermometry. In this work, it is described the emissivity measurement of high-emissivity black paint that has been used for the two applications described above. The average emissivity of the measured paint in the 8 to 14 micrometers wavelength range was estimated as 0.972 ± 0.012. The results obtained may be of use for those using the paint at temperatures from 50 to 150 grades C. (Author)

  1. Laser-induced Field Emission from Tungsten Tip: Optical Control of Emission Sites and Emission Process

    OpenAIRE

    Yanagisawa, H.; Hafner, C; Doná, P; Klöckner, M; Leuenberger, D.; Greber, T.; Osterwalder, J; Hengsberger, M.

    2010-01-01

    Field-emission patterns from a clean tungsten tip apex induced by femtosecond laser pulses have been investigated. Strongly asymmetric field-emission intensity distributions are observed depending on three parameters: (i) the polarization of the light, (ii) the azimuthal, and (iii) the polar orientation of the tip apex relative to the laser incidence direction. In effect, we have realized an ultrafast pulsed field-emission source with site selectivity of a few tens of nanometers. Simulations ...

  2. Emission allowances stall in marketplace

    International Nuclear Information System (INIS)

    Misinformation and public misunderstanding have given emissions trading a bad reputation in the public marketplace, says William F. Malec, executive vice president of the Tennessee Valley Authority (TVA), in Knoxville, Tennessee. Media coverage of a May 1992 emissions-allowance trade between TVA and Wisconsin Power and Light open-quotes focused on the agreement's pollution-trading aspects, not its overall potential economic and environmental benefits,close quotes Malec says. Such negative portrayal of TVA's transaction sparked severe public criticism and charges that emissions trading gives utilities the right to pollute. open-quotes The fact is that TVA sought the emissions-trading agreement as a means to reduce overall emissions in the most cost-effective way,close quotes Malec explains. Emissions trading allows a company with emission levels lower than clean-air standards to earn open-quotes credits.close quotes These credits then may be purchased by a company with emission levels that exceed federal standards. Under this arrangement, the environment is protected and companies that buy credits save money because they do not have to purchase expensive emissions-control devices or reduce their production levels. Malec says TVA decided to enter into the emissions-allowance market, not only to cut costs, but also to publicize the existence and benefits of emissions trading. However, TVA's experience proves that open-quotes people will not accept what they do not understand,close quotes concludes Malec, open-quotes especially when complex environmental issues are involved.close quotes

  3. Anthropogenic mercury emissions in China

    Science.gov (United States)

    Streets, David G.; Hao, Jiming; Wu, Ye; Jiang, Jingkun; Chan, Melissa; Tian, Hezhong; Feng, Xinbin

    An inventory of mercury emissions from anthropogenic activities in China is compiled for the year 1999 from official statistical data. We estimate that China's emissions were 536 (±236) t of total mercury. This value includes open biomass burning, but does not include natural sources or re-emission of previously deposited mercury. Approximately 45% of the Hg comes from non-ferrous metals smelting, 38% from coal combustion, and 17% from miscellaneous activities, of which battery and fluorescent lamp production and cement production are the largest. Emissions are heaviest in Liaoning and Guangdong Provinces, where extensive smelting occurs, and in Guizhou Province, where there is much small-scale combustion of high-Hg coal without emission control devices. Emissions are gridded at 30×30 min spatial resolution. We estimate that 56% of the Hg in China is released as Hg 0, 32% as Hg 2+, and 12% as Hg p. Particulate mercury emissions are high in China due to heavy burning of coal in residential and small industrial settings without PM controls. Emissions of Hg 2+ from coal-fired power plants are high due to the absence of flue-gas desulfurization units, which tend to dissolve the soluble divalent mercury. Metals smelting operations favor the production of elemental mercury. Much of the Hg is released from small-scale activities in rather remote areas, and therefore the activity levels are quite uncertain. Also, emissions test data for Chinese sources are lacking, causing uncertainties in Hg emission factors and removal efficiencies. Overall, we calculate an uncertainty level of ±44% (95% confidence interval) in the estimate of total emissions. We recommend field testing of coal combustors and smelters in China to improve the accuracy of these estimates.

  4. Carbon emissions and an equitable emission reduction criterion

    International Nuclear Information System (INIS)

    In 1995 the world-wide carbon emissions reached 5.8 billion metric tonnes per year (GTC/y). The Kyoto protocol calls for a reduction of carbon emissions from the developed countries (Annex I countries) of 6-8% below 1990 levels on the average, and unspecified commitments for the less developed (non-Annex I) countries. It is doubtful that the Kyoto agreement will be ratified by some parliaments, especially the USA Congress. Furthermore, it is shown that if the non-Annex I countries will not curtail their carbon emissions drastically, the global emissions will soar to huge levels by the middle of the next century. An equitable emission criterion is proposed which may lead to a sustainable rate of growth of carbon emissions, and be acceptable to all countries of the world. The criterion links the rate of growth of carbon emissions to the rate of growth of the Gross Domestic Product (GDP). A target criterion is proposed R = 0.15 KgC/SGDP, which is the current average for western European countries and Japan. This allows for both the growth of the GDP and carbon emissions. However, to reach the target in a reasonable time, the countries for which R≤ 0.3 would be allowed a carbon emission growth rate of 1%./y, and countries for which R≥ 0.3, 0.75%/y. It is shown that by 2050 the world-wide carbon emissions would reach about 10 GTC/y, which is about 3 times less than the Kyoto agreement would allow. (Author)

  5. Maritime emissions: modeling and measuring policy effects

    OpenAIRE

    Vanherle, K.; Van Zeebroeck, B.

    2008-01-01

    Maritime emissions have long time been a low priority issue for policy makers. However, maritime emissions will be included in the European National Emission Ceilings (NEC) and as maritime transport is increasing rapidly, its share in emissions is thought to become more significant.So maritime emissions are becoming more important for national and international policy makers, and pressure is rising to reduce emissions. As such, policy makers need a tool to estimate current emissions and to as...

  6. A Safety Valve for Emissions Trading

    OpenAIRE

    John Stranlund

    2009-01-01

    This paper considers the optimal design of an emissions trading program that includes a safety valve tax that allows pollution sources to escape the emissions cap imposed by the aggregate supply of emissions permits. I demonstrate that an optimal hybrid emissions trading/emissions tax policy involves a permit supply that is strictly less than under a pure emissions trading scheme and a safety valve tax that exceeds the optimal pure emissions tax as long as expected marginal damage is an incre...

  7. Future Emissions from Railway Traffic

    DEFF Research Database (Denmark)

    Sorenson, Spencer C.

    1998-01-01

    In investigation of the expected development in factors which influence railway energy consumption and emissions. Traffic factors such as train speed, load, an occupancy were considered. Tehcnical factors such an emissions factors, fleet composition and train weight were also considered. An...

  8. Emission of formaldehyde from furniture

    DEFF Research Database (Denmark)

    Andersen, Helle Vibeke; Klinke, Helene B.; Funch, Lis Winther;

    2014-01-01

    The emission of formaldehyde from a variety of furniture was measured in climate chambers. Most tests show low emission of formaldehyde; however, there are a few exceptions. One product emitted significant amounts of formaldehyde, but according to the Danish Indoor Climate Labelling Criteria for ...

  9. Emission of formaldehyde from furniture

    DEFF Research Database (Denmark)

    Andersen, Helle Vibeke; Klinke, Helene B.; Funch, Lis Winther;

    The emission of formaldehyde from 20 pieces of furniture, representing a variety of types, was measured in climate chambers. Most tests show low emissions but certain scenarios of furnishing, including furniture with large surface areas in relation to room volume can emit formaldehyde resulting i...

  10. Climate policy: Reforming emissions trading

    Science.gov (United States)

    Edenhofer, Ottmar

    2014-08-01

    Courageous steps are required to reform the European Union Emissions Trading Scheme. To this end, an independent carbon authority has been proposed -- this is a move in the right direction, but should be part of a much broader discussion about reforming emissions trading.

  11. NEC-2020 emission reduction scenarios

    DEFF Research Database (Denmark)

    Slentø, Erik; Nielsen, Ole-Kenneth; Hoffmann, Leif;

    The upcoming NEC-2020 EU directive sets up emission ceilings for NOX, SO2, NH3, NMVOC and PM in order to meet the environmental exposure targets of the Thematic Strategy. This report contains an assessment of intermediary emission reduction scenarios for Denmark, computed by the GAINS model 2007...

  12. Deliberating emission reduction options

    Energy Technology Data Exchange (ETDEWEB)

    Dowd, A.M.; Rodriguez, M.; Jeanneret, T. [Commonwealth Scientific and Industrial Research Organisation CSIRO, 37 Graham Rd, Highett VIC 3190 (Australia); De Best-Waldhober, M.; Straver, K.; Mastop, J.; Paukovic, M. [Energy research Centre of the Netherlands ECN, Policy Studies, Amsterdam (Netherlands)

    2012-06-15

    For more than 20 years there has been a concerted international effort toward addressing climate change. International conventions, such as the United Nations Foreign Convention on Climate Change (UNFCCC; ratified in 1994), have been established by committed nations seeking to address global climate change through the reduction of greenhouse gases emitted into the Earth's atmosphere (Global CCS Institute, 2011). Long recognised as the most crucial of the greenhouse gases to impact global warming, the majority of carbon dioxide's anthropogenic global emissions are directly related to fuel combustion of which both Australia and the Netherlands' energy production is significantly reliant. Both these nations will need to consider many opinions and make hard decisions if alternative energy options are to be implemented at the scale that is required to meet international emission targets. The decisions that are required not only need to consider the many options available but also their consequences. Along with politicians, policy developers and industry, the general public also need to be active participants in deciding which energy options, and their subsequent consequences, are acceptable for implementation at the national level. Access to balanced and factual information is essential in establishing informed opinions on the many policy options available. Past research has used several methods to measure public perceptions and opinions yet for complex issues, such as emission reduction, some of these methods have shown to be problematic. For example, semi structured interviews can provide data that is flexible and context rich yet is does also come with the limitations such as it seldom provides a practical assessment that can be utilised from researcher to researcher, across disciplines and public participation techniques. Surveys on the other hand usually address these limitations but surveys that do not encourage comparison of information or ask

  13. Low Temperature Emissivity Measurement System

    Directory of Open Access Journals (Sweden)

    Jignesh A. Patel

    2014-05-01

    Full Text Available The emissivity of a material is the relative ability of its surface to emit energy by radiation. It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature. Knowledge about the low temperature emissivity of materials and coatings can be essential to the design of fusion cryoplants and in the thermal modeling for space satellite missions. The emittance of materials at cryogenics temperatures often cannot be predicted from room temperature data, but for computing radiative loads and infrared backgrounds this cryogenic data is often required. Measurement of the cryogenic emissivity of a highly reflective surface is a significant challenge: little thermal power is radiated from the sample, and the background radiation. However some researchers have measured emissivity at various low temperature ranges. Present work reports, the various emissivity measurement setup and their considerations.

  14. Nanoparticle emissions from combustion engines

    CERN Document Server

    Merkisz, Jerzy

    2015-01-01

     This book focuses on particulate matter emissions produced by vehicles with combustion engines. It describes the physicochemical properties of the particulate matter, the mechanisms of its formation and its environmental impacts (including those on human beings). It discusses methods for measuring particulate mass and number, including the state-of-the-art in Portable Emission Measurement System (PEMS) equipment for measuring the exhaust emissions of both light and heavy-duty vehicles and buses under actual operating conditions. The book presents the authors’ latest investigations into the relations between particulate emission (mass and number) and engine operating parameters, as well as their new findings obtained through road tests performed on various types of vehicles, including those using diesel particulate filter regeneration. The book, which addresses the needs of academics and professionals alike, also discusses relevant European regulations on particulate emissions and highlights selected metho...

  15. Photophysics of fullerenes: Thermionic emission

    International Nuclear Information System (INIS)

    Multiphoton ionization of fullerenes using long-pulse length lasers occurs mainly through vibrational autoionization. In many cases the laser ionization can be described as thermionic in analogy to the boiling off of electrons from a filament. Thermionic emission manifests itself as a delayed emission of electrons following pulsed laser excitation. Klots has employed quasiequilibrium theory to calculate rate constants for thermionic emission from fullerenes which seem to quantitatively account for the observed delayed emission times and the measured electron energy distributions. The theory of Klots also accounts for the thermionic emission of C60 excited by a low power CW Argon Ion laser. Recently Klots and Compton have reviewed the evidence for thermionic emission from small aggregates where mention was also made of experiments designed to determine the effects of externally applied electric fields on thermionic emission rates. The authors have measured the fullerene ion intensity as a function of the applied electric field and normalized this signal to that produced by single photon ionization of an atom in order to correct for all collection efficiency artifacts. The increase in fullerene ion signal relative to that of Cs+ is attributed to field enhanced thermionic emission. From the slope of the Schottky plot they obtain a temperature of approximately 1,000 K. This temperature is comparable to but smaller than that estimated from measurements of the electron kinetic energies. This result for field enhanced thermionic emission is discussed further by Klots and Compton. Thermionic emission from neutral clusters has long been known for autodetachment from highly excited negative ions. Similarly, electron attachment to C60 in the energy range from 8 to 12 eV results in C60 anions with lifetimes in the range of microseconds. Quasiequilibrium theory (QET) calculations are in reasonable accord with these measurements

  16. Photophysics of fullerenes: Thermionic emission

    Energy Technology Data Exchange (ETDEWEB)

    Compton, R.N. [Univ. of Tennessee, Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States); Tuinman, A.A. [Univ. of Tennessee, Knoxville, TN (United States); Huang, J. [Ames Lab., IA (United States)

    1996-09-01

    Multiphoton ionization of fullerenes using long-pulse length lasers occurs mainly through vibrational autoionization. In many cases the laser ionization can be described as thermionic in analogy to the boiling off of electrons from a filament. Thermionic emission manifests itself as a delayed emission of electrons following pulsed laser excitation. Klots has employed quasiequilibrium theory to calculate rate constants for thermionic emission from fullerenes which seem to quantitatively account for the observed delayed emission times and the measured electron energy distributions. The theory of Klots also accounts for the thermionic emission of C{sub 60} excited by a low power CW Argon Ion laser. Recently Klots and Compton have reviewed the evidence for thermionic emission from small aggregates where mention was also made of experiments designed to determine the effects of externally applied electric fields on thermionic emission rates. The authors have measured the fullerene ion intensity as a function of the applied electric field and normalized this signal to that produced by single photon ionization of an atom in order to correct for all collection efficiency artifacts. The increase in fullerene ion signal relative to that of Cs{sup +} is attributed to field enhanced thermionic emission. From the slope of the Schottky plot they obtain a temperature of approximately 1,000 K. This temperature is comparable to but smaller than that estimated from measurements of the electron kinetic energies. This result for field enhanced thermionic emission is discussed further by Klots and Compton. Thermionic emission from neutral clusters has long been known for autodetachment from highly excited negative ions. Similarly, electron attachment to C{sub 60} in the energy range from 8 to 12 eV results in C{sub 60} anions with lifetimes in the range of microseconds. Quasiequilibrium theory (QET) calculations are in reasonable accord with these measurements.

  17. AGN coronal emission models - I. The predicted radio emission

    Science.gov (United States)

    Raginski, I.; Laor, Ari

    2016-06-01

    Accretion discs in active galactic nucleus (AGN) may be associated with coronal gas, as suggested by their X-ray emission. Stellar coronal emission includes radio emission, and AGN corona may also be a significant source for radio emission in radio quiet (RQ) AGN. We calculate the coronal properties required to produce the observed radio emission in RQ AGN, either from synchrotron emission of power-law (PL) electrons, or from cyclosynchrotron emission of hot mildly relativistic thermal electrons. We find that a flat spectrum, as observed in about half of RQ AGN, can be produced by corona with a disc or a spherical configuration, which extends from the innermost regions out to a pc scale. A spectral break to an optically thin power-law emission is expected around 300-1000 GHz, as the innermost corona becomes optically thin. In the case of thermal electrons, a sharp spectral cut-off is expected above the break. The position of the break can be measured with very long baseline interferometry observations, which exclude the cold dust emission, and it can be used to probe the properties of the innermost corona. Assuming equipartition of the coronal thermal energy density, the PL electrons energy density, and the magnetic field, we find that the energy density in a disc corona should scale as ˜R-1.3, to get a flat spectrum. In the spherical case the energy density scales as ˜R-2, and is ˜4 × 10-4 of the AGN radiation energy density. In Paper II we derive additional constraints on the coronal parameters from the Gudel-Benz relation, Lradio/LX-ray ˜ 10- 5, which RQ AGN follow.

  18. Emissions from RDF combustion

    International Nuclear Information System (INIS)

    The paper deals with the emissions from refuse derived fuel (RDF) combustion. The disposal of refuse has during the last years been a matter of increasing concern for many municipalities. The environment options for waste disposal has not been focusing much. This means that first the waste generation must be reduced. Then recycling of a portion of the waste must be considered before a solution with combustion of waste is chosen. Two methods are currently in use for the combustion of municipal solid waste (MSW) which are the mass burning of unprocessed MSW and RDF. The RDF product consists of the burnable organic fraction of raw MSW. In contrast to mass burning systems, the RDF-system is pre-processing the raw MSW to make a more homogeneous fuel product. By processing the MSW, it is possible to recover RDF and other materials. The RDF process is a low cost approach to resource recovery. RDF is a merchant fuel, and can be used in existing boilers alone or as a supplement to conventional fuels as oil and coal. It is important that the RDF processing technology and RDF quality matches the energy user requirements. The RDF-processing-systems is of great importance to the RDF quality. The paper shows the different steps in the RDF process. 4 refs., 15 figs

  19. Methane emission from sewers.

    Science.gov (United States)

    Liu, Yiwen; Ni, Bing-Jie; Sharma, Keshab R; Yuan, Zhiguo

    2015-08-15

    Recent studies have shown that sewer systems produce and emit a significant amount of methane. Methanogens produce methane under anaerobic conditions in sewer biofilms and sediments, and the stratification of methanogens and sulfate-reducing bacteria may explain the simultaneous production of methane and sulfide in sewers. No significant methane sinks or methanotrophic activities have been identified in sewers to date. Therefore, most of the methane would be emitted at the interface between sewage and atmosphere in gravity sewers, pumping stations, and inlets of wastewater treatment plants, although oxidation of methane in the aeration basin of a wastewater treatment plant has been reported recently. Online measurements have also revealed highly dynamic temporal and spatial variations in methane production caused by factors such as hydraulic retention time, area-to-volume ratio, temperature, and concentration of organic matter in sewage. Both mechanistic and empirical models have been proposed to predict methane production in sewers. Due to the sensitivity of methanogens to environmental conditions, most of the chemicals effective in controlling sulfide in sewers also suppress or diminish methane production. In this paper, we review the recent studies on methane emission from sewers, including the production mechanisms, quantification, modeling, and mitigation. PMID:25889543

  20. Pricing hazardous substance emissions

    Energy Technology Data Exchange (ETDEWEB)

    Staring, Knut; Vennemo, Haakon

    1997-12-31

    This report discusses pricing of emissions to air of several harmful substances. It combines ranking indices for environmentally harmful substances with economic valuation data to yield price estimates. The ranking methods are discussed and a relative index established. Given the relative ranking of the substances, they all become valued by assigning a value to one of them, the `anchor` substance, for which lead is selected. Valuations are provided for 19 hazardous substances that are often subject to environmental regulations. They include dioxins, TBT, etc. The study concludes with a discussion of other categories of substances as well as uncertainties and possible refinements. When the valuations are related to CO, NOx, SOx and PM 10, the index system undervalues these pollutants as compared to other studies. The scope is limited to the outdoor environment and does not include global warming and eutrophication. The indices are based on toxicity and so do not apply to CO{sub 2} or other substances that are biologically harmless. The index values are not necessarily valid for all countries and should be considered as preliminary. 18 refs., 6 tabs.

  1. Emission-free valve

    Energy Technology Data Exchange (ETDEWEB)

    Koppe, W.; Prummer, R.

    1980-07-01

    a description is given of an emission-free valve, particularly a magnetically operated valve, for use in controlling the flow of fluids, especially poisonous, radioactive, aggressive and otherwise dangerous gases and fluids, comprising a housing including a housing member which has substantially spherical configuration and an internal surface surrounding a compartment for the respective fluid, said housing further including an annular valve seat member; a valve member movably mounted in said compartment and cooperating with said valve seat member to control the flow of the fluid through said compartment; and a plating layer of a corrosion-resistant material covering said internal surface of said housing member and also having a substantially spherical configuration corresponding to that of said housing member, said housing member and said plating layer obtaining their respective configurations during an explosion which not only simultaneously deforms initially cylindrical tubular and coaxially arranged housing member and plating layer preforms, but also welds said plating layer preform to said housing member preform so that said platinglayer is explosion-welded to said housing member.

  2. Diffuse Microwave Emission Survey

    Science.gov (United States)

    Shafer, R. A.; Mather, J.; Kogut, A.; Fixsen, D. J.; Seiffert, M.; Lubin, P. M.; Levin, S. M.

    1996-12-01

    The Diffuse Microwave Emission Survey (DIMES) is a mission concept selected by NASA in 1995 to answer fundamental questions about the content and history of the universe. DIMES will use a set of absolutely calibrated cryogenic radiometers from a space platform to measure the frequency spectrum of the cosmic microwave background (CMB) at wavelengths 15--0.3 cm (frequency 2--100 GHz) to precision 0.1 mK or better. Measurements at centimeter wavelengths probe different physical processes than the COBE-FIRAS spectra at shorter wavelengths, and complement the anisotropy measurements from DMR, balloon and ground-based instruments, and the planned MAP and COBRAS/SAMBA satellites. DIMES will observe the free-free signal from early photoionization to establish the precise epoch of structure formation, and will measure or limit energy release at redshift 10(4) theory and allowed by current measurement limits; even an upper limit at the expected sensitivity 10(-5) MJy/sr will place important constraints on the matter content, structure, and evolution of the universe. Detecting these distortions or showing that they do not exist constitutes the last frontier of CMB observations.

  3. 40 CFR 61.123 - Emission testing.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Emission testing. 61.123 Section 61.123... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standards for Radionuclide Emissions From Elemental Phosphorus Plants § 61.123 Emission testing. (a) Each owner or operator of an elemental...

  4. 40 CFR 61.32 - Emission standard.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Emission standard. 61.32 Section 61.32... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium § 61.32 Emission standard. (a) Emissions to the atmosphere from stationary sources subject to the provisions of this...

  5. 40 CFR 61.67 - Emission tests.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Emission tests. 61.67 Section 61.67... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Vinyl Chloride § 61.67 Emission tests. (a) Unless a waiver of emission testing is obtained under § 61.13, the owner or operator...

  6. 40 CFR 61.42 - Emission standard.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Emission standard. 61.42 Section 61.42... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor Firing § 61.42 Emission standard. (a) Emissions to the atmosphere from rocket-motor test sites shall...

  7. 40 CFR 61.162 - Emission limits.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Emission limits. 61.162 Section 61.162... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Inorganic Arsenic Emissions From Glass Manufacturing Plants § 61.162 Emission limits. (a) The owner or operator of an...

  8. 40 CFR 61.52 - Emission standard.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Emission standard. 61.52 Section 61.52... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Mercury § 61.52 Emission standard. (a) Emissions to the atmosphere from mercury ore processing facilities and mercury cell...

  9. Advanced Collaborative Emissions Study (ACES)

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, Daniel; Costantini, Maria; Van Erp, Annemoon; Shaikh, Rashid; Bailey, Brent; Tennant, Chris; Khalek, Imad; Mauderly, Joe; McDonald, Jacob; Zielinska, Barbara; Bemis, Jeffrey; Storey, John; Hallberg, Lance; Clark, Nigel

    2013-12-31

    The objective of the Advanced Collaborative Emissions Study (ACES) was to determine before widespread commercial deployment whether or not the new, energy-efficient, heavy duty diesel engines (2007 and 2010 EPA Emissions Standards Compliant) may generate anticipated toxic emissions that could adversely affect the environment and human health. ACES was planned to take place in three phases. In Phase 1, extensive emissions characterization of four production-intent prototype engine and control systems designed to meet 2007 standards for nitrogen oxides (NOx) and particulate matter (PM) was conducted at an existing emissions characterization facility: Southwest Research Institute (SwRI). One of the tested engines was selected (at random, after careful comparison of results) for health testing in Phase 3. In Phase 2, extensive emission characterization of three production-intent prototype engine and control systems meeting the 2010 standards (including more advanced NOx controls to meet the more stringent 2010 NOx standards) was conducted at the same test facility. In Phase 3, one engine/aftertreatment system selected from Phase 1 was further characterized during health effects studies (at an existing inhalation toxicology laboratory: Lovelace Respiratory Research Institute, [LRRI]) to form the basis of the ACES safety assessment. The Department of Energy (DOE) award provided funding for emissions characterization in Phases 1 and 2 as well as exposure characterization in Phase 3. The main health analyses in Phase 3 were funded separately and are not reported here.

  10. Aircraft emissions at Turkish airports

    International Nuclear Information System (INIS)

    This paper deals with estimating aircraft landing and take-off (LTO) emissions (HC, CO, NOx, SO2) at 40 Turkish airports including the biggest airports, i.e. Ataturk International Airport (AIA) in Istanbul, Antalya Airport in Antalya and Esenboga Airport in Ankara in 2001. The calculation model is based on flight data recorded by the State Airports Authority. The flight data include the type and number of aircraft, number of passengers, amount of cargo etc., which depend on day-time and date. For the emission calculations the International Civil Aviation Organization (ICAO)-Engine emission data bank, which includes minimum and maximum values for both fuel flow rates and emissions factors, is used. By using first the minimum and then the maximum values from the data bank, two estimations of aircraft LTO emissions at Turkish airports are calculated: i.e. minimum and maximum estimations. Total LTO emissions from aircraft at Turkish airports are estimated to be between 7614.34 and 8338.79 t/year. These results are comparable with those from USA airports. Approximately half of these amounts are produced at AIA. To predict future emissions, it is estimated that an increase of 25% in LTO cycles might cause a rise of between 31 and 33% in emissions. The estimations show that a decrease of 2 min in taxiing time results in a decrease of 6% in LTO emissions. The estimation model used in this study can be used for expansions and planning of airports from an environmental point of view. (author)

  11. Biomass burning: Combustion emissions, satellite imagery, and biogenic emissions

    International Nuclear Information System (INIS)

    This chapter deals with two different, but related, aspects of biomass burning. The first part of the chapter deals with a technique to estimate the instantaneous emissions of trace gases produced by biomass burning using satellite imagery. The second part of the chapter concerns the recent discovery that burning results in significantly enhanced biogenic emissions of N2O, NO, and CH4. Hence, biomass burning has both an immediate and long-term impact on the production of trace gases to the atmosphere. The objective of this research is to better assess and quantify the role of this research is to better assess and quantify the role and impact of biomass as a driver for global change. It will be demonstrated that satellite imagery of fires may be used to estimate combustion emissions and may in the future be used to estimate the long-term postburn biogenic emissions of trace gases to the atmosphere

  12. Emissions for Sale : The Ethics of Emissions Trading

    OpenAIRE

    Paulsson, Fredrik

    2003-01-01

    International regulations target a global reduction of carbon dioxide (CO2) emissions through the allocation of national reduction targets and the definition of mechanisms to achieve these targets. One of these mechanisms is international emissions trading, these trading programs have been the targets of widespread criticism since they were introduced into the policy-making arena. The point of departure in this study has been that the trading raises questions about morality, since it implies ...

  13. Microwave emission and crop residues

    Science.gov (United States)

    Jackson, Thomas J.; O'Neill, Peggy E.

    1991-01-01

    A series of controlled experiments were conducted to determine the significance of crop residues or stubble in estimating the emission of the underlying soil. Observations using truck-mounted L and C band passive microwave radiometers showed that for dry wheat and soybeans the dry residue caused negligible attenuation of the background emission. Green residues, with water contents typical of standing crops, did have a significant effect on the background emission. Results for these green residues also indicated that extremes in plant structure, as created using parallel and perpendicular stalk orientations, can cause very large differences in the degree of attenuation.

  14. Reducing ammonia emissions in Europe

    DEFF Research Database (Denmark)

    Jacobsen, Brian H.

    The NEC directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the largest reductions since 1990...... not lived up to the high expectations at the outset. Despite this, the paper concludes that Denmark is likely to reduce emission by 50% from 1990 to 2020 and reach the likely 2020 NEC ceiling....

  15. Radio emission in Mercury magnetosphere

    OpenAIRE

    Varela, J.; Reville, V.; Brun, A. S.; Pantellini, F.; Zarka, P.

    2016-01-01

    Context: Active stars possess magnetized wind that has a direct impact on planets that can lead to radio emission. Mercury is a good test case to study the effect of the solar wind and interplanetary magnetic field on radio emission driven in the planet magnetosphere. Such studies could be used as proxies to characterize the magnetic field topology and intensity of exoplanets. Aims: The aim of this study is to quantify the radio emission in the Hermean magnetosphere. Methods: We use the MHD c...

  16. Zero emission city. Preliminary study; Null-Emissions-Stadt. Sondierungsstudie

    Energy Technology Data Exchange (ETDEWEB)

    Diefenbach, N.; Enseling, A.; Werner, P.; Flade, A.; Greiff, R.; Hennings, D.; Muehlich, E.; Wullkopf, U.; Sturm, P.; Kieslich, W.; Born, R.; Grossklos, M.; Hatteh, R.; Mueller, K.; Ratschow, A.; Valouch-Fornoff, C.

    2002-10-01

    The idea of a 'zero emission city' is investigated by the Institut Wohnen und Umwelt on behalf of the Federal Minister of Education and Research. After describing the current situation and defining the key parameters of a 'zero emission city', settlement structures, power supply, production processes and transportation are analyzed and linked with the communal action level to obtain a framework for research, activities and actions. The study ends with recommendations for a research programme 'zero emission city'. (orig.) [German] Die von den Staedten der Industrielaender ausgehenden Emissionen stellen im Hinblick auf die globalen Belastungen wie z.B. Treibhauseffekt, Ozonabbau und Versauerung das Hauptproblem dar. Aus diesem Grunde bietet es sich an, den Gedanken der 'Null-Emissions-Stadt', der Vision einer moeglichst emissionsfreien Stadt, aufzugreifen und auf seine Tragfaehigkeit fuer innovative Handlungsmodelle forschungsstrategisch zu ueberpruefen. Das Bundesministerium fuer Bildung und Forschung hat das Institut Wohnen und Umwelt beauftragt, in einer Sondierungsstudie dieser Fragestellung nachzugehen. Nach der Festlegung der Ausgangsbedingungen und Eckpunkte der Vision 'Null-Emissions-Stadt' und der Analyse der vier Handlungsfelder Siedlungsstrukturen, Energieversorgung, Produktionsprozesse (Kreislaufwirtschaft) und Verkehr werden diese aufgegriffen und mit der kommunalen Handlungsebene verknuepft und zu einem Forschungs-, Handlungs- und moeglichen Aktionsrahmen zusammengefuegt. Die Studie schliesst mit Hinweisen fuer die Gestaltung eines Forschungsprogramms 'Null-Emissions-Stadt'. (orig.)

  17. The Effects of Differentiated Emission Taxes

    OpenAIRE

    Takeda, Shiro

    2001-01-01

    Extending the standard 2 x 2 Heckscher-Ohlin-Samuelson model to include emission as the third production factor, we consider the effects of emission taxes on outputs and the level of emission. The following results are derived. First, an increase in emission tax imposed on one industry may paradoxically increase the outputs of the industry. Second, an increase in emission tax imposed on one industry may raise the total level of emission.

  18. Cleaning the Diesel Engine Emissions

    DEFF Research Database (Denmark)

    Christensen, Thomas Budde

    This paper examines how technologies for cleaning of diesel emission from road vehicles can be supported by facilitating a technology push in the Danish automotive emission control industry. The European commission is at present preparing legislation for the euro 5 emission standard (to be enforced...... in 2010). The standard is expected to include an 80% reduction of the maximum particulate emissions from diesel cars. The fulfillment of this requirement entails development and production of particulate filters for diesel cars and trucks. Theoretically the paper suggests a rethinking of public...... industry policy based on Michael Porters cluster theory. The paper however suggest that the narrow focus on productivity and economic growth in Porters theory should be qualified and integrated with a broader scope of societal policy aims including social and environmental issues. This suggestion also...

  19. Emissivity measurements on aeronautical alloys

    Energy Technology Data Exchange (ETDEWEB)

    Campo, L. del, E-mail: leire.del-campo@cnrs-orleans.f [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Perez-Saez, R.B., E-mail: raul.perez@ehu.e [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Instituto de Sintesis y Estudio de Materiales, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao (Spain); Gonzalez-Fernandez, L. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Esquisabel, X.; Fernandez, I. [Industria de Turbo Propulsores, S.A., Planta de Zamudio, Edificio 300, 48170 Zamudio, Bizkaia (Spain); Gonzalez-Martin, P. [Industria de Turbo Propulsores, S.A., Parque empresarial San Fernando, Avda. Castilla 2, 28830 San Fernando de Henares, Madrid (Spain); Tello, M.J. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Instituto de Sintesis y Estudio de Materiales, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao (Spain)

    2010-01-21

    The emissivity of three Ni and Co based aeronautical alloys is analyzed in this paper. These alloys are employed in high temperature environments whenever good corrosion resistance, high temperature resistance and high strength are essential. Thus, apart from the aeronautical industry, these alloys are also used in other technological applications, as for example, aerospace, nuclear reactors, and tooling. The results in this paper extend the emissivity data for these alloys available in the literature. Emissivity dependence on the radiation wavelength (2-22 {mu}m), sample temperature (200-650 {sup o}C) and emission angle (0-85{sup o}) has been investigated. In addition, the effect of surface finish and oxidation has also been taken into consideration. The data in this paper have several applications, as temperature measurement of a target by pyrometry, low observability of airplanes and thermal radiation heat transfer simulation in airplane nozzles or furnaces.

  20. The Emissions Gap Report 2015

    DEFF Research Database (Denmark)

    Following the historic signing of the 2030 Agenda for Sustainable Development, this sixth edition of the UNEP Emissions Gap Report comes as world leaders start gathering in Paris to establish a new agreement on climate change. The report offers an independent assessment of the mitigation contribu......Following the historic signing of the 2030 Agenda for Sustainable Development, this sixth edition of the UNEP Emissions Gap Report comes as world leaders start gathering in Paris to establish a new agreement on climate change. The report offers an independent assessment of the mitigation...... contributions from the Intended Nationally Determined Contributions (INDC) committed to by 1 October 2015, by the 146 countries that account for around 90 per cent of global emissions. It compares the 2030 emission levels that would result from these commitments with what science tells us would keep average...

  1. Advanced Emissions Control Development Program

    Energy Technology Data Exchange (ETDEWEB)

    A.P.Evans; K.E. Redinger; M.J. Holmes

    1998-04-01

    The objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of air toxics from coal-fired boilers. Ideally, the project aim is to effectively control air toxic emissions through the use of conventional flue gas cleanup equipment such as electrostatic precipitators (ESPS), fabric filters (baghouse), and wet flue gas desulfurization. Development work to date has concentrated on the capture of mercury, other trace metals, fine particulate and hydrogen chloride. Following the construction and evaluation of a representative air toxics test facility in Phase I, Phase II focused on the evaluation of mercury and several other air toxics emissions. The AECDP is jointly funded by the United States Department of Energy's Federal Energy Technology Center (DOE), the Ohio Coal Development Office within the Ohio Department of Development (oCDO), and Babcock& Wilcox-a McDermott company (B&W).

  2. Controlling radiated emissions by design

    CERN Document Server

    Mardiguian, Michel

    2014-01-01

    The 3rd edition of Controlling Radiated Emissions by Design has been updated to reflect the latest changes in the field. New to this edition is material related to technical advances, specifically super-fast data rates on wire pairs, with no increase in RF interference. Throughout the book, details are given to control RF emissions using EMC design techniques. This book retains the step-by-step approach for incorporating EMC into every new design from the ground up. It describes the selection of quieter IC technologies, their implementation into a noise-free printed circuit layout, and the gathering of these into a low emissions package. Also included is how to design an I/O filter, along with connectors and cable considerations. All guidelines are supported throughout with comprehensive calculated examples. Design engineers, EMC specialists, and technicians will benefit from learning about the development of more efficient and economical control of emissions.

  3. Alcohol polymerization using electron emission

    International Nuclear Information System (INIS)

    We report a means of instantaneous alcohol polymerization using electron emission at room temperature. We selected 1-butanol as a source of alcohol polymer. A 1-butanol molecule has a simple molecular structure and is a good candidate for analyzing reaction mechanisms. Direct electron emission onto the surface of volatile 1-butanol prevented intense discharge and gently composed 1-butanol-polymer at room temperature in air. The strategy enabled exciting liquids and instantaneously composing new materials at room temperature

  4. Emissivity of rocket plume particulates.

    OpenAIRE

    Whisman, Curtis D.

    1992-01-01

    The optical properties of motor aluminum oxide are required inputs to current plume signature prediction codes, such as SIRRM. Accurate predictions are possible only if variations in the particle emissivity due to changes in particle size, contamination, and changing temperature, etc. , are known . This investigation demonstrated a simplified method for determination of the emissivity of rocket motor generated alumina. Plume particulate material was collected on ...

  5. Thermal emissivity of avian eggshells.

    Science.gov (United States)

    Björn, Lars Olof; Bengtson, Sven-Axel; Li, Shaoshan; Hecker, Christoph; Ullah, Saleem; Roos, Arne; Nilsson, Annica M

    2016-04-01

    The hypothesis has been tested that evolution has resulted in lower thermal emissivity of eggs of birds breeding openly in cold climates than of eggs of birds that nest under protective covering or in warmer climates. Directional thermal emissivity has been estimated from directional-hemispherical reflectance spectra. Due to several methodological difficulties the absolute emissivity is not accurately determined, but differences between species are obvious. Most notably, small waders of the genus Calidris, breeding in cold climates on the tundra, and in most cases with uniparental nest attendance, have low directional emissivity of their eggshells, about 0.92 when integration is carried out for wavelengths up to 16μm. Species belonging to Galloanserinae have the highest directional emissivity, about 0.96, of their eggs. No differences due to climate or breeding conditions were found within this group. Eggs of most other birds tested possess intermediate emissivity, but the values for Pica pica and Corvus corone cornix are as low as for Calidris. Large species-dependent differences in spectral reflectance were found at specific wavelengths. For instance, at 4.259μm the directional-hemispherical reflectance for galliforms range from 0.05 to 0.09, while for Fratercula arctica and Fulmarus glacialis it is about 0.3. The reflection peaks at 6.5 and 11.3μm due to calcite are differentially attenuated in different species. In conclusion, the hypothesis that evolution has resulted in lower thermal emissivity of bird eggs being exposed in cold climates is not supported by our results. The emissivity is not clearly related to nesting habits or climate, and it is unlikely that the small differences observed are ecologically important. The spectral differences between eggs that nevertheless exist should be taken into account when using infrared thermometers for estimating the surface temperature of avian eggs. PMID:27033033

  6. Low Temperature Emissivity Measurement System

    OpenAIRE

    Jignesh A. Patel

    2014-01-01

    The emissivity of a material is the relative ability of its surface to emit energy by radiation. It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature. Knowledge about the low temperature emissivity of materials and coatings can be essential to the design of fusion cryoplants and in the thermal modeling for space satellite missions. The emittance of materials at cryogenics temperatures often cannot be predicted f...

  7. Pollutant emissions from modern incinerators

    OpenAIRE

    Lima, R.; Bachmann, R

    2002-01-01

    Presently, emissions of dioxins are mainly from incinerators, domestic and industrial coal combustion, and traffic. However, the major public concern and research effort are associated with the emissions of organic micropollutants from waste incinerators. Therefore, this paper attempts to give a brief overview on the more recent research and development for the removal of dioxins and heavy metals from flue gas streams. Special attention is devoted to the origin and control of e...

  8. Methane Emissions from Upland Forests

    Science.gov (United States)

    Megonigal, Patrick; Pitz, Scott; Wang, Zhi-Ping

    2016-04-01

    Global budgets ascribe 4-10% of atmospheric methane sinks to upland soils and assume that soils are the sole surface for methane exchange between upland forests and the atmosphere. The dogma that upland forests are uniformly atmospheric methane sinks was challenged a decade ago by the discovery of abiotic methane production from plant tissue. Subsequently a variety of relatively cryptic microbial and non-microbial methane sources have been proposed that have the potential to emit methane in upland forests. Despite the accumulating evidence of potential methane sources, there are few data demonstrating actual emissions of methane from a plant surface in an upland forest. We report direct observations of methane emissions from upland tree stems in two temperate forests. Stem methane emissions were observed from several tree species that dominate a forest located on the mid-Atlantic coast of North America (Maryland, USA). Stem emissions occurred throughout the growing season while soils adjacent to the trees simultaneously consumed methane. Scaling fluxes by stem surface area suggested the forest was a net methane source during a wet period in June, and that stem emissions offset 5% of the soil methane sink on an annual basis. High frequency measurements revealed diurnal cycles in stem methane emission rates, pointing to soils as the methane source and transpiration as the most likely pathway for gas transport. Similar observations were made in an upland forest in Beijing, China. However, in this case the evidence suggested the methane was not produced in soils, but in the heartwood by microbial or non-microbial processes. These data challenge the concept that forests are uniform sinks of methane, and suggest that upland forests are smaller methane sinks than previously estimated due to stem emissions. Tree emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration.

  9. Estimating emissions from railway traffic

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, M.W.; Sorenson, C.

    1997-07-01

    The report discusses methods that can be used to estimate the emissions from various kinds of railway traffic. The methods are based on the estimation of the energy consumption of the train, so that comparisons can be made between electric and diesel driven trains. Typical values are given for the necessary traffic parameters, emission factors, and train loading. Detailed models for train energy consumption are presented, as well as empirically based methods using average train speed and distance between stop. (au)

  10. Reducing environmental emissions in tanneries.

    Science.gov (United States)

    van Groenestijn, J W; Langerwerf, J S A; Lucas, M

    2002-01-01

    Tanning, in particular chrome leather production, is still characterised by an inefficient use of raw material and the production of highly polluted wastewater and solid wastes. A part of the emissions can be prevented by introducing clean tanning technologies, the remaining emissions can be treated. Clean production technologies and waste (water) treatment technologies should have a designed complimentarity. Anaerobic wastewater treatment with recovery of sulfides, sulfur and energy (biogas) is a cornerstone in such integral clean chrome leather technology. PMID:12046670

  11. Emission Impacts of Electric Vehicles

    OpenAIRE

    Wang, Quanlu; DeLuchi, Mark A.; Sperling, Daniel

    1990-01-01

    Alternative vehicular fuels are proposed as a strategy to reduce urban air pollution. In this paper, we analyze the emission impacts of electric vehicles in California for two target years, 1995 and 2010. We consider a range of assumptions regarding electricity consumption of electric vehicles, emission control technologies for power plants, and the mix of primary energy sources for electricity generation. We find that, relative to continued use of gasoline-powered vehicles, the use of electr...

  12. Nitrous oxide emissions in Austria

    International Nuclear Information System (INIS)

    The report contains the documentation of a presentation given at the conference 'Greenhouse Gases: Mitigation Options' organised by the IEA Greenhouse Gas R and D Programme from 22-25 August 1995 in London. Using IPCC recommended procedures, anthropogenic emissions of nitrous oxide (N2O) in Austria for the base year 1990 were estimated to be around 4,800 metric tons (t). The uncertainties are high particularly for the emissions from agricultural soils. About 62 % of total emissions come from agriculture, 26 % from the energy sector, and 11 % from the industrial processes sector. Projections for the year 2000 show that emissions will grow by about 15 %. This is mainly due to unwanted side-effects of pollution control technologies (e.g. 3-way catalytic converters for cars, fluidised bed combustion in industry, and denitrification processes in waste water treatment plants). The national emission estimates were spatially disaggregated to a district level using a top-down model. Arithmetic average and median emission densities in the districts are 1.2 and 0.6 kg per hectare. (author)

  13. Price floors for emissions trading

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Peter John, E-mail: Peter.J.Wood@anu.edu.a [Resource Management in Asia Pacific Program, Crawford School of Economics and Government, Australian National University, Canberra ACT 0200 (Australia); Jotzo, Frank, E-mail: frank.jotzo@anu.edu.a [Resource Management in Asia Pacific Program, Crawford School of Economics and Government, Australian National University, Canberra ACT 0200 (Australia)

    2011-03-15

    Price floors in greenhouse gas emissions trading schemes can guarantee minimum abatement efforts if prices are lower than expected, and they can help manage cost uncertainty, possibly as complements to price ceilings. Provisions for price floors are found in several recent legislative proposals for emissions trading. Implementation however has potential pitfalls. Possible mechanisms are government commitments to buy back permits, a reserve price at auction, or an extra fee or tax on acquittal of emissions permits. Our analysis of these alternatives shows that the fee approach has budgetary advantages and is more compatible with international permit trading than the alternatives. It can also be used to implement more general hybrid approaches to emissions pricing. - Research highlights: {yields} Price floors for emissions trading schemes guarantee a minimum carbon price. {yields} Price floors mean that emissions can be less than specified by the ETS cap. {yields} We examine how price floors can relate to different policy objectives. {yields} We compare different mechanisms for implementing a price floor. {yields} We find that a mechanism where there is an extra tax or fee has advantages.

  14. Price floors for emissions trading

    International Nuclear Information System (INIS)

    Price floors in greenhouse gas emissions trading schemes can guarantee minimum abatement efforts if prices are lower than expected, and they can help manage cost uncertainty, possibly as complements to price ceilings. Provisions for price floors are found in several recent legislative proposals for emissions trading. Implementation however has potential pitfalls. Possible mechanisms are government commitments to buy back permits, a reserve price at auction, or an extra fee or tax on acquittal of emissions permits. Our analysis of these alternatives shows that the fee approach has budgetary advantages and is more compatible with international permit trading than the alternatives. It can also be used to implement more general hybrid approaches to emissions pricing. - Research highlights: → Price floors for emissions trading schemes guarantee a minimum carbon price. → Price floors mean that emissions can be less than specified by the ETS cap. → We examine how price floors can relate to different policy objectives. → We compare different mechanisms for implementing a price floor. → We find that a mechanism where there is an extra tax or fee has advantages.

  15. Methane emissions in the Netherlands

    International Nuclear Information System (INIS)

    Methane is the most important greenhouse gas after carbon dioxide. Detailed national emission estimates are needed to narrow the gap between world emission estimates and budget results from atmospheric chemistry. These estimates have to be based on sound emission factors and better extrapolation of methane measurement results. The article identifies the most important sources of methane in the Netherlands as landfills, ruminants, manure and the production, distribution and combustion of gas. It explains that emissions from landfills will decrease as a result of policies to reduce landfilling. The encouragement of increased internal use of otherwise vented gas on oil and gas production platforms and the planned extra maintenance of destribution networks should further decrease emissions. Policies to reduce milk and beef surplus and the introduction of new types of stabling and manure handling systems will reduce emissions in the agriculture sector. These measures should produce a total reduction of methane of 20% in 2000 with respect to 1990 levels. 5 refs., 3 figs., 2 tabs

  16. Offsetting Ongoing Methane Emissions --- An Alternative to Emission Equivalence Metrics

    Science.gov (United States)

    Clisby, N.; Enting, I. G.; Lauder, A.; Carter, J.; Cowie, A.; Henry, B.; Raupach, M. R.

    2012-12-01

    The Global Warming Potential (GWP) has been widely adopted as a metric for comparing the climate impact of different greenhouse gases. As has been frequently noted, there are many problems with using GWPs to define emission equivalence in spite of the use of GWPs for this purpose in contexts such as the Kyoto Protocol. We propose that for methane, rather than define emission equivalence, the appropriate comparison is between ongoing emissions of 0.9 to 1.0 kg of CH4 per year and one-off emissions of 1 tonne of carbon. This approach represents an approximate solution to the inverse problem of defining a forcing equivalent index (FEI) that gives exact equivalence of radiative forcing over a range of timescales. In our approach, if ongoing methane emissions are offset by a one-off carbon removal that is built up with 40-year e-folding time, then the result is close to radiatively neutral over periods from years to centuries. In contrast, the GWP provides radiative equivalence (in integrated terms) only at a single time, with large discrepancies at other times. Our approach also follows from consideration of greenhouse gas stabilisation, since stabilising atmospheric CO2 requires an approximate cap on total emissions, while stabilising methane requires stabilisation of ongoing emissions. Our quantitative treatment recognises that, on time scales of centuries, removal of 1 tonne of carbon only lowers the atmospheric carbon content by 0.3 to 0.35 tonnes. We discuss the implications for rangeland grazing systems. In the absence of effective mitigation techniques for methane from rangeland systems, this approach may provide an attractive offset mechanism in spite of requiring that woody vegetation be established and maintained over about 15% of the landscape, or an equivalent amount of carbon storage in soil.

  17. ECO2, Emissions Trading Services, development project

    International Nuclear Information System (INIS)

    Emissions Trading started within EU at the beginning of 2005. It caused substantial changes to the business environment of energy companies and energy intensive industry. The planning of Emissions Trading is a complicated process and companies will need consulting, IT systems and other services. Emissions Trading introduces a new factor of production emission allowances, which are tradable commodities. In future, Emissions Trading emissions, emission allowances and the prices of emission allowances have to be considered during the fuel purchasing and the energy production planning. And the best possible knowledge of the own emissions balance and market situation has a monetary value when trading emission allowances. Allocation of emission allowances has done in each country according to National Allocation Plan (NAP), accepted by EU. Finland itself and thus also the Finnish companies will be net buyers of emission allowances in long run. That means commonly that the Finnish companies have to buy more allowances meaning some extra costs to the companies. That's why it is very important to develop and provide to the companies an innovatory emissions planning, follow-up, management and reporting systems. With good emission balance management the extra costs of Emissions Trading will be as low as possible. In ECO2 project, Empower together with Power-Deriva, developed Expert services, Emissions Balance Management and Reporting services and Risk Management services for Emissions Trading and needed software and tools for these services. (orig.)

  18. Austrian emission inventory for dust

    International Nuclear Information System (INIS)

    For the first time, Austrian emissions of anthropogenic particulate matter emissions to the atmosphere have been estimated. Results have been reported as total suspended particles (TSP) as well as for the fractions of particles smaller than 10 μm or 2.5 μm aerodynamic diameter (PM10, PM2.5), respectively. Base years for the inventory were 1990, 1995 and 1999. Excluded from this assessment is wind blown dust, which has been considered a natural source here. National statistics have been applied, specifically those also used previously in the Austrian air pollution inventory (OLI). Emission factors have been taken from literature compilations, only for exceptional cases specific Austrian assessments were performed or original literature on emission measurements was consulted. Resuspension of dust by road traffic emerged as the most important source. For the size fraction of PM10 this source contributed about half of the emissions, when applying the calculation scheme by the U.S. EPA. While this scheme is widely used and well documented, its validity is currently subject of intense scientific debate. As these results do not seem to coincide with ambient air measurements, resuspension of road dust is considered separately and not now included in the national total. The sum of all other sources increases from 75,000 t of TSP in 1990 and 1995 to 77,000 t in 1999, while both PM10 and PM2.5 exhibit decreasing tendency (at 45,000 t and 26,000 t in 1999, respectively). The increase in TSP derives from increasing traffic and friction related emissions (tire wear, break wear), decrease of the finer particulate matter is due to reductions in firewood consumption for domestic heating. Most important source sectors are fugitive emissions from material transfer in industry as well as the building industry and the tilling of agricultural land. Common to these sources is the high uncertainty of available data. Wood combustion is the most important of the non-fugitive emissions

  19. 10 CFR 300.6 - Emissions inventories.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Emissions inventories. 300.6 Section 300.6 Energy... Emissions inventories. (a) General. The objective of an emission inventory is to provide a full accounting... emission inventory must be prepared in accordance with Chapter 1 of the Technical Guidelines...

  20. Diffuse Galactic Emission from Spinning Dust Grains

    OpenAIRE

    Draine, B. T.; Lazarian, A.

    1997-01-01

    Spinning interstellar dust grains produce detectable rotational emission in the 10-100 GHz frequency range. We calculate the emission spectrum, and show that this emission can account for the ``anomalous'' Galactic background component which correlates with 100um thermal emission from dust. Implications for cosmic background studies are discussed.

  1. 40 CFR 89.119 - Emission tests.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Emission tests. 89.119 Section 89.119... EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Standards and Certification Provisions § 89.119 Emission tests. (a) Manufacturer testing. (1) Upon completion of service...

  2. 47 CFR 24.133 - Emission limits.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Emission limits. 24.133 Section 24.133... SERVICES Narrowband PCS § 24.133 Emission limits. (a) The power of any emission shall be attenuated below... the lesser attenuation. (b) The measurements of emission power can be expressed in peak or...

  3. 40 CFR 63.112 - Emission standard.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Emission standard. 63.112 Section 63...) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards... Process Vents, Storage Vessels, Transfer Operations, and Wastewater § 63.112 Emission standard. (a)...

  4. Cooperative spontaneous emission in nonuniform media

    OpenAIRE

    Rudziński, Adam

    2010-01-01

    The subject of this paper is modification of cooperative spontaneous emission by a nonuniform medium, with nonuniform distributions of electromagnetic field. A brief analyzis is presented and it is postulated, that if spontaneous emission from an atom is strongly suppressed, cooperative emission with another atom may be a preferred emission channel and counteract the suppression.

  5. 40 CFR 63.802 - Emission limits.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Emission limits. 63.802 Section 63.802... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Wood Furniture Manufacturing Operations § 63.802 Emission limits. (a) Each owner or...

  6. 40 CFR 76.11 - Emissions averaging.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Emissions averaging. 76.11 Section 76...) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.11 Emissions averaging. (a) General provisions. In lieu of complying with the applicable emission limitation in § 76.5, 76.6, or 76.7,...

  7. 47 CFR 74.794 - Digital emissions.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Digital emissions. 74.794 Section 74.794... Booster Stations § 74.794 Digital emissions. (a)(1) An applicant for a digital LPTV or TV translator... emissions within one of the following emission masks: simple or stringent. (2) The power level of...

  8. Thermal Radio Emission as Incoherent Induced Radiation

    OpenAIRE

    Prigara, Fedor V.

    2001-01-01

    The synchrotron interpretation of radio emission from various astrophysical objects encounters the essential difficulties . These difficulties may be overcome in a new theory of thermal radio emission of non-uniform gas which is based on a stimulated character of thermal radio emission following from the relations between Einstein?s coefficients for spontaneous and induced emission of radiation .

  9. Trading emissions improve air quality

    International Nuclear Information System (INIS)

    While admitting sharply contrasting views exist, James M. Lents of the South Coast Air Quality Management District in southern California sees emissions trading open-quotes as a lifesaver for our troubled planet.close quotes He explains: open-quotes If political support for the environment is to be maintained, we must seek the most economical and flexible means of pursuing cleanup. At present, market incentives and emissions trading represent our best hope.close quotes Lents is putting his money where his pen is. The air quality management district he heads plans to use market incentives, including emissions trading, to reduce air pollution in the notoriously dirty southern California area. When the system goes into operation in 1994, he estimates it will save southern California businesses more than $400 million a year in compliance costs, while also making major improvements in the region's air quality. If the idea works there, why won't it work elsewhere, even on a global scale, Lents asks? He believes it will. But open-quotes the ultimate success of emissions-trading programs, whether regional, national, or international in scope, lies in the proof that they're actually achieving reductions in harmful emissions,close quotes he emphasizes. open-quotes These reductions must be real and verifiable to satisfy the Clean Air Act and a skeptical public.close quotes

  10. Emission scenario model for regional air pollution

    OpenAIRE

    Karvosenoja, Niko

    2008-01-01

    Air pollution emissions are produced in a wide variety of sources. They often result in detrimental impacts on both environments and human populations. To assess the emissions and impacts of air pollution, mathematical models have been developed. This study presents results from the application of an air pollution emission model, the Finnish Regional Emission Scenario (FRES) model, that covers the emissions of sulfur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3), non-methane volatile or...

  11. China's Carbon Emissions 1971-2003

    OpenAIRE

    Chunbo Ma; Stern, David I.

    2007-01-01

    A number of previous studies on China's carbon emissions have mainly focused on two facts: 1) the continuous growth in emissions up till the middle of the 1990s; 2) the recent stability of emissions from 1996 to 2001. Decomposition analysis has been widely used to explore the driving forces behind these phenomena. However, since 2002, China's carbon emissions have resumed their growth at an even greater rate. This paper investigates China's carbon emissions during 1971-2003, with particular f...

  12. Embodied greenhouse gas emission by Macao

    International Nuclear Information System (INIS)

    Comprehensive inventory of cities' greenhouse gas emissions (GHG) is the basis for cities to make appropriate mitigation plans. However, previous studies on cities' GHG emissions consider emissions occurring within the city boundary (Scope 1) and out of boundary electricity emissions (Scope 2), but neglect indirect emissions associated with commodities consumed by cities (Scope 3), resulting in emission leakage. To cope with this problem, a systematic accounting covering all 3 scopes is presented in a case study of Macao for the years 2005–2009, based on the latest embodied emission intensity databases for China and for the world. The results show that total emissions are dominated by indirect emissions mainly embodied in imports, which is 3–4 times direct emissions during the period concerned. It is verified that accounting under Scopes 1 and 2 cannot capture the full picture of cities' emissions, especially cities like Macao which are dominated by service industry and inevitably sustained by massive materials and services from other regions. Our study suggests that Macao should adjust its current GHG mitigation policies which consider only its emissions occurring within its border, as Macao is a net GHG emissions importer. This work is the first assessment of Macao's embodied GHG emissions. - Highlights: • A systematic accounting procedure is presented to inventory a city's GHG emissions. • A comprehensive review of GHG emissions is performed for Macao. • Indirect GHG emissions dominate Macao's embodied GHG emissions. • Macao induced large amount of GHG emissions in other regions through trade. • The variation in GHG emission structure against socio-economic changes is revealed

  13. Part III: Total Greenhouse Gas Emissions

    OpenAIRE

    OLIVIER Jos; Janssens-Maenhout, Greet

    2014-01-01

    CO2 emissions from fuel combustion represent the majority of anthropogenic GHG emissions. However, comprehensive analysis of emission trends considers other sources of CO2 as well as other gases, knowing that data on gases and sources other than CO2 from fuel combustion are much more uncertain. Country- specific estimates of CO2 from biomass burning and F-gas emissions are particularly difficult to ascertain. To complement work regarding the emissions of CO2 from fuel combustion, the IEA elec...

  14. Bankruptcy Risk and Imperfectly Enforced Emissions Taxes

    OpenAIRE

    John K. Stranlund; Wei Zhang

    2008-01-01

    Under favorable but reasonable conditions, an imperfectly enforced emissions tax produces the efficient allocation of individual emissions control; aggregate emissions are independent of whether enforcement of the tax is sufficient to induce the full compliance of firms, and differences in individual violations are independent of firm-level differences. All of these desirable characteristics disappear when some firms under an emissions tax risk bankruptcy—the allocation of emissions control i...

  15. Industrial emissions of 1,3-butadiene.

    OpenAIRE

    Mullins, J A

    1990-01-01

    Sources of industrial emissions of 1,3-butadiene are discussed both by process (production, consumers) and type (equipment leaks, point sources). Quantification of the emissions are presented, as reported by the U.S. Environmental Protection Agency in 1986. The reported emissions attributed to equipment leaks (also known as fugitive emissions) range from about 50 to 95% of the total, depending on the specific production process used. The methods by which these emissions were estimated are dis...

  16. Highly Emissive Covalent Organic Frameworks.

    Science.gov (United States)

    Dalapati, Sasanka; Jin, Enquan; Addicoat, Matthew; Heine, Thomas; Jiang, Donglin

    2016-05-11

    Highly luminescent covalent organic frameworks (COFs) are rarely achieved because of the aggregation-caused quenching (ACQ) of π-π stacked layers. Here, we report a general strategy to design highly emissive COFs by introducing an aggregation-induced emission (AIE) mechanism. The integration of AIE-active units into the polygon vertices yields crystalline porous COFs with periodic π-stacked columnar AIE arrays. These columnar AIE π-arrays dominate the luminescence of the COFs, achieve exceptional quantum yield via a synergistic structural locking effect of intralayer covalent bonding and interlayer noncovalent π-π interactions and serve as a highly sensitive sensor to report ammonia down to sub ppm level. Our strategy breaks through the ACQ-based mechanistic limitations of COFs and opens a way to explore highly emissive COF materials. PMID:27108740

  17. High mobility emissive organic semiconductor

    Science.gov (United States)

    Liu, Jie; Zhang, Hantang; Dong, Huanli; Meng, Lingqiang; Jiang, Longfeng; Jiang, Lang; Wang, Ying; Yu, Junsheng; Sun, Yanming; Hu, Wenping; Heeger, Alan J.

    2015-12-01

    The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm2 V-1 s-1. Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m-2 and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics.

  18. Controlling carbon emissions in China

    International Nuclear Information System (INIS)

    We examine the use of carbon taxes to reduce emissions of CO2 in China. To do so, we develop a dynamic computable general equilibrium (CGE) model of the Chinese economy. In addition to accounting for the effects of population growth, capital accumulation, technological change, and changing patterns of demand, we also incorporate into our model elements of the dual nature of China's economy where both plan and market institutions exist side by side. We conduct simulations in which carbon emissions are reduced by 5, 10, and 15 per cent from our baseline. After initial declines, in all of our simulations GDP and consumption rapidly exceed baseline levels as the revenue neutral carbon tax serves to transfer income from consumers to producers and then into increased investment. Although subject to a number of caveats, we find potential for what is in some sense a double dividend, a decrease in emissions for CO2 and a long run increase in GDP and consumption. (Author)

  19. Air Emission Inventory for the Idaho National Engineering and Environmental Laboratory - Calendar Year 1999 Emission Report

    Energy Technology Data Exchange (ETDEWEB)

    Zohner, S.K.

    2000-05-30

    This report presents the 1999 calendar year update of the Air Emission Inventory for the Idaho National Engineering and Environmental Laboratory (INEEL). The INEEL Air Emission Inventory documents sources and emissions of nonradionuclide pollutants from operations at the INEEL. The report describes the emission inventory process and all of the sources at the INEEL, and provides nonradionuclide emissions estimates for stationary sources.

  20. Air Emission Inventory for the Idaho National Engineering and Environmental Laboratory - Calendar Year 1998 Emissions Report

    Energy Technology Data Exchange (ETDEWEB)

    S. K. Zohner

    1999-10-01

    This report presents the 1998 calendar year update of the Air Emission Inventory for the Idaho National Engineering and Environmental Laboratory (INEEL). The INEEL Air Emission Inventory documents sources and emissions of nonradionuclide pollutants from operations at the INEEL. The report describes the emission inventory process and all of the sources at the INEEL, and provides nonradiological emissions estimates for stationary sources.

  1. Air emission inventory for the Idaho National Engineering Laboratory: 1994 emissions report

    International Nuclear Information System (INIS)

    This report Presents the 1994 update of the Air Emission inventory for the Idaho National Engineering Laboratory (INEL). The INEL Air Emission Inventory documents sources and emissions of non-radionuclide pollutants from operations at the INEL. The report describes the emission inventory process and all of the sources at the INEL, and provides non-radionuclide emissions estimates for stationary sources

  2. Emission current from a single micropoint of explosive emission cathode

    International Nuclear Information System (INIS)

    Explosive emission cathodes (EECs) are widely used due to their large current. There has been much research on the explosive electron emission mechanism demonstrating that a current density of 108–109 A/cm2 is necessary for a micropoint to explode in several nanoseconds and the micropoint size is in micron-scale according to the observation of the cathode surface. This paper, however, makes an effort to research the current density and the micropoint size in another way which considers the space charge screening effect. Our model demonstrates that the relativistic effect is insignificant for the micropoint emission due to the small size of the micropoint and uncovers that the micron-scale size is an intrinsic demand for the micropoint to reach a space charge limited current density of 108–109 A/cm2. Meanwhile, our analysis shows that as the voltage increases, the micropoint emission will turn from a field limited state to a space charge limited state, which makes the steady-state micropoint current density independent of the cathode work function and much less dependent on the electric field and the field enhancement factor than that predicted by the Fowler-Nordheim formula

  3. Transportable Emissions Testing Laboratory for Alternative Vehicles Emissions Testing

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Nigel

    2012-01-31

    The overall objective of this project was to perform research to quantify and improve the energy efficiency and the exhaust emissions reduction from advanced technology vehicles using clean, renewable and alternative fuels. Advanced vehicle and alternative fuel fleets were to be identified, and selected vehicles characterized for emissions and efficiency. Target vehicles were to include transit buses, school buses, vocational trucks, delivery trucks, and tractor-trailers. Gaseous species measured were to include carbon monoxide, carbon dioxide, oxides of nitrogen, hydrocarbons, and particulate matter. An objective was to characterize particulate matter more deeply than by mass. Accurate characterization of efficiency and emissions was to be accomplished using a state-of-the-art portable emissions measurement system and an accompanying chassis dynamometer available at West Virginia University. These two units, combined, are termed the Transportable Laboratory. An objective was to load the vehicles in a real-world fashion, using coast down data to establish rolling resistance and wind drag, and to apply the coast down data to the dynamometer control. Test schedules created from actual vehicle operation were to be employed, and a specific objective of the research was to assess the effect of choosing a test schedule which the subject vehicle either cannot follow or can substantially outperform. In addition the vehicle loading objective was to be met better with an improved flywheel system.

  4. Particles Emission from Gasoline Vehicles

    Institute of Scientific and Technical Information of China (English)

    WANG Jun-fang; GE Yun-shan; TAN Jian-wei; HE Chao; YOU Ke-wei; YOU Qiu-wen

    2009-01-01

    Number concentration and size distribution from gasoline cars are investigated at transient modes on the chassis dynamometers,which are measured using electrical low pressure impactor (ELPI) for the ECE15 and EUDC cycles.Results indicate that,during cold start,particle number emission is higher than that under hot start.It is found that the number of particles increases with the vehicle speeds.Furthermore,particles with diameter smaller than 200 nm constitute the predominant part of total emission in the entire cycle.In addition,the tentative information about composition of emitted particles is also discussed.

  5. Sonification of acoustic emission data

    Science.gov (United States)

    Raith, Manuel; Große, Christian

    2014-05-01

    While loading different specimens, acoustic emissions appear due to micro crack formation or friction of already existing crack edges. These acoustic emissions can be recorded using suitable ultrasonic transducers and transient recorders. The analysis of acoustic emissions can be used to investigate the mechanical behavior of different specimens under load. Our working group has undertaken several experiments, monitored with acoustic emission techniques. Different materials such as natural stone, concrete, wood, steel, carbon composites and bone were investigated. Also the experimental setup has been varied. Fire-spalling experiments on ultrahigh performance concrete and pullout experiments on bonded anchors have been carried out. Furthermore uniaxial compression tests on natural stone and animal bone had been conducted. The analysis tools include not only the counting of events but the analysis of full waveforms. Powerful localization algorithms and automatic onset picking techniques (based on Akaikes Information Criterion) were established to handle the huge amount of data. Up to several thousand events were recorded during experiments of a few minutes. More sophisticated techniques like moment tensor inversion have been established on this relatively small scale as well. Problems are related to the amount of data but also to signal-to-noise quality, boundary conditions (reflections) sensor characteristics and unknown and changing Greens functions of the media. Some of the acoustic emissions recorded during these experiments had been transferred into audio range. The transformation into the audio range was done using Matlab. It is the aim of the sonification to establish a tool that is on one hand able to help controlling the experiment in-situ and probably adjust the load parameters according to the number and intensity of the acoustic emissions. On the other hand sonification can help to improve the understanding of acoustic emission techniques for training

  6. Exoelectron emission from magnesium surfaces

    Science.gov (United States)

    Klar, F.; Bansmann, J.; Glaefeke, H.; Fitting, H.-J.; Meiwes-Broer, K.-H.

    1999-12-01

    Clean magnesium surfaces were created by evaporating Mg onto silicon wafers. When exposing the Mg surface to a low oxygen partial pressure, an exoelectron emission (EEE) is observed after a time delay of the order of several hours after evaporation. On a much shorter time scale, similar effects in exoemission from Mg and alkali metals have been observed previously. The results are discussed within a 'potential emission' model of exoelectrons during oxygen capture at the pure Mg surface, but extending the model by including an escape mechanism. A macroscopic quantitative description of the model is given, which is in good agreement with our measurements.

  7. NMF on positron emission tomography

    DEFF Research Database (Denmark)

    Bödvarsson, Bjarni; Hansen, Lars Kai; Svarer, Claus;

    2007-01-01

    In positron emission tomography, kinetic modelling of brain tracer uptake, metabolism or binding requires knowledge of the cerebral input function. Traditionally, this is achieved with arterial blood sampling in the arm or as shown in (Liptrot, M, et al., 2004) by non-invasive K-means clustering....... We propose another method to estimate time-activity curves (TAC) extracted directly from dynamic positron emission tomography (PET) scans by non-negative matrix factorization (NMF). Since the scaling of the basis curves is lost in the NMF the estimated TAC is scaled by a vector alpha which is...

  8. Ordering multiple soft gluon emissions

    CERN Document Server

    Ángeles-Martínez, René; Seymour, Michael H

    2016-01-01

    We present an expression for the QCD amplitude for a general hard scattering process with any number of soft gluon emissions, to one-loop accuracy. The amplitude is written in two different but equivalent ways: as a product of operators ordered in dipole transverse momentum and as a product of loop-expanded currents. We hope that these results will help in the development of an all-orders algorithm for multiple emissions that includes the full colour structure and both the real and imaginary contributions to the amplitude.

  9. Shell theorem for spontaneous emission

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Mortensen, Jakob Egeberg; Lodahl, Peter; Stobbe, Søren

    2013-01-01

    We investigate spontaneous emission from excitons beyond the point source dipole approximation and show how the symmetry of the exciton wave function plays a crucial role. We find that for spherically symmetric wave functions, the Purcell effect is independent of the wave function size and...... therefore is given exactly by the dipole approximation theory. This surprising result is a spontaneous emission counterpart to the shell theorems of classical mechanics and electrostatics and provides insights into the physics of mesoscopic emitters as well as great simplifications in practical calculations....

  10. Power station stack gas emissions

    International Nuclear Information System (INIS)

    There are increasing awareness and pressure to reduce emissions of acid rain and photochemical smog. There is a need to produce new control system and equipment to capture those emissions. The most visible form of pollutions are the chimney smoke, dust and particles of fly ash from mineral matter in the fuel. Acid gases are hard on structures and objects containing limestone. Coal fired power generation is likely to be able to sustain its competitive advantage as a clean source of electricity in comparison with nuclear power and natural gas

  11. ORGANIC EMISSIONS FROM AUTOMOBILE INTERIORS

    Science.gov (United States)

    The report gives results of an evaluation of six subcompact automobiles for the emission of vinyl chloride monomer (VCM) and other organics into the passenger compartment. Evaluated were a Ford Pinto, AMC Gremlin, GMC Vega, GMC Chevette, NMC Datsun 710, and VW Rabbit. VCM was qua...

  12. Radio emission in Mercury magnetosphere

    CERN Document Server

    Varela, J; Brun, A S; Pantellini, F; Zarka, P

    2016-01-01

    Context: Active stars possess magnetized wind that has a direct impact on planets that can lead to radio emission. Mercury is a good test case to study the effect of the solar wind and interplanetary magnetic field on radio emission driven in the planet magnetosphere. Such studies could be used as proxies to characterize the magnetic field topology and intensity of exoplanets. Aims: The aim of this study is to quantify the radio emission in the Hermean magnetosphere. Methods: We use the MHD code PLUTO in spherical coordinates with an axisymmetric multipolar expansion for the Hermean magnetic field, to analyze the effect of the interplanetary magnetic field (IMF) orientation and intensity, as well as the hydrodynamic parameters of the solar wind (velocity, density and temperature), on the net power dissipated on the Hermean day and night side. We apply the formalism derived by Zarka [2001, 2007] to infer the radio emission level from the net dissipated power. We perform a set of simulations with different hydr...

  13. Fiber optics spectrochemical emission sensors

    Science.gov (United States)

    Griffin, J.W.; Olsen, K.B.

    1992-02-04

    A method is described of in situ monitoring of a body of a fluid stored in a tank or groundwater or vadose zone gases in a well for the presence of selected chemical species. The method uses a probe insertable into the well or tank via a cable and having an electrical apparatus for exciting selected chemical species in the body of fluid. The probe can have a pair of electrodes for initiating a spark or a plasma cell for maintaining a plasma to excite the selected chemical species. The probe also has an optical apparatus for receiving optical emissions emitted by the excited species and optically transmitting the emissions via the cable to an analysis location outside the well. The analysis includes detecting a selected wavelength in the emissions indicative of the presence of the selected chemical species. A plurality of probes can be suspended at an end of a respective cable, with the transmitting and analyzing steps for each probe being synchronized sequentially for one set of support equipment and instrumentation to monitor at multiple test points. The optical apparatus is arranged about the light guide axis so that the selected chemical species are excited in the fluid in alignment with the light guide axis. Optical emissions are received from the excited chemical species along such axis. 18 figs.

  14. Livestock and greenhouse gas emissions

    DEFF Research Database (Denmark)

    Herrero, M; Gerber, P; Vellinga, T;

    2011-01-01

    Estimates of global greenhouse gases (GHG) emissions attributable to livestock range from 8 to 51%. This variability creates confusion among policy makers and the public as it suggests that there is a lack of consensus among scientists with regard to the contribution of livestock to global GHG em...

  15. Carbon emissions of infrastructure development.

    Science.gov (United States)

    Müller, Daniel B; Liu, Gang; Løvik, Amund N; Modaresi, Roja; Pauliuk, Stefan; Steinhoff, Franciska S; Brattebø, Helge

    2013-10-15

    Identifying strategies for reconciling human development and climate change mitigation requires an adequate understanding of how infrastructures contribute to well-being and greenhouse gas emissions. While direct emissions from infrastructure use are well-known, information about indirect emissions from their construction is highly fragmented. Here, we estimated the carbon footprint of the existing global infrastructure stock in 2008, assuming current technologies, to be 122 (-20/+15) Gt CO2. The average per-capita carbon footprint of infrastructures in industrialized countries (53 (± 6) t CO2) was approximately 5 times larger that that of developing countries (10 (± 1) t CO2). A globalization of Western infrastructure stocks using current technologies would cause approximately 350 Gt CO2 from materials production, which corresponds to about 35-60% of the remaining carbon budget available until 2050 if the average temperature increase is to be limited to 2 °C, and could thus compromise the 2 °C target. A promising but poorly explored mitigation option is to build new settlements using less emissions-intensive materials, for example by urban design; however, this strategy is constrained by a lack of bottom-up data on material stocks in infrastructures. Infrastructure development must be considered in post-Kyoto climate change agreements if developing countries are to participate on a fair basis. PMID:24053762

  16. Visible light emission from silicon

    International Nuclear Information System (INIS)

    Although crystalline silicon is not expected to emit light in the visible range, bright red emission has been reported for high porosity porous silicon films. This recent discovery which opens the door to silicon-based optoelectronics has raised up a great interest in the scientific community, and the paper presents the state of art of the question after a year of investigations. After a short presentation of the main features of porous silicon, the different characteristics of the photoluminescence phenomena are described in some detail. In this paper, the evolution of the emission spectra with the properties of the material which can be varied by chemical or electrochemical methods are presented. Results confirm that quantum size effects within the crystalline material can be responsible for the light emission far above the band gap of silicon. Bright electroluminescence has also been evidenced during anodic oxidation of the material. The dependence of this emission with the material properties and the characteristics of the oxidation process will be discussed and compared t the photoluminescence features

  17. Emissions Trading: Trends and Prospects

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    This paper provides the latest developments of announced, proposed and existing greenhouse gas emissions trading schemes (ETS) around the world since 2006. It also examines different potential design options for ETS (e.g. coverage, allocation mode, provision for offsets), and how these options are treated in the existing, announced or proposed schemes.

  18. Recharging Emission-Free Cars

    Institute of Scientific and Technical Information of China (English)

    CORRIE; DOSH

    2008-01-01

    New York dealership begins sales of China-made electric vehicles In the 2006 documentary Who Killed the Electric Car?, Director Chris Paine showed how auto manufacturers, the oil industry, government officials and consumers suppressed the development of allelectric, emission-free vehicles. Now, with

  19. Primary particles in ship emissions

    Science.gov (United States)

    Fridell, Erik; Steen, Erica; Peterson, Kjell

    There is not much data available regarding particle emissions from ships. In this study the size distributions of particles in ship exhaust from three different ships in normal operational conditions were studied using a cascade impactor. The ships were equipped with slow- or medium-speed main engines and medium-speed auxiliary engines. The fuel was residual oil except for the auxiliary engines on one ship which used marine diesel. Large emissions and a dependence of the sulfur content in the fuel were observed. High amounts of relatively large particles (around 8 μm) were observed. These are attributed to re-entrained soot particles from walls in the engine systems. A strong variation between different ships was observed for the particle-size distribution and for the dependence on engine load. The particle emissions were found to be reduced to about half, over the whole size range, by an SCR system. The total particle emission, measured after dilution, varied between 0.3 and 3 g kW h -1 depending on load, fuel and engine.

  20. INFRARED EMISSIVITY OF CONDUCTING POLYMERS

    Institute of Scientific and Technical Information of China (English)

    WAN Meixiang; LI Suzhen; LI Junchao; DONG Haiou

    1991-01-01

    The infrared emissivity of conducting polymers in 8-20μm and at 50-150℃ in the direction of normal line has been measured as a function of wavelength, conductivity at room temperature,counterion, doping levels, measuring temperature and thickness of sample.

  1. Emission Trading under the Kyoto Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Holtsmark, Bjart; Hagem, Cathrine

    1998-12-01

    This report discusses the potential gains from emission trading and raises some crucial questions. It shows that the total costs of the Kyoto Protocol could be reduced by about 95% through emission trading. Emission trading is an option also in the domestic arenas. The governments of the Annex B countries may allocate emission quotas to local enterprises as emission permits. Thus new markets for greenhouse gas emission quotas may emerge, domestically and internationally. It is emphasized that emission trading at the national and international levels must be discussed separately. The Nordic governments, for example, will find several good reasons for supporting emission trading at the international level if not necessarily domestically. The Nordic countries have already implemented domestic taxes on CO{sub 2} emissions and this tax policy could be sustained while these governments support and take part in emission trading at the international level.The report also considers a possible side effect of emission trading: free emission trading among Annex B countries could reduce the total abatement compared to a non-tradable policy as a consequence of the fact that some of the countries that are in transition to a market economy may be given emission limitations above their business-as-usual emissions. 40 refs., 7 figs., 4 tabs.

  2. Projecting future HFC-23 emissions

    Directory of Open Access Journals (Sweden)

    B. R. Miller

    2011-08-01

    Full Text Available A Reference Case (RC scenario for emissions of HFC-23 from co-production during HCFC-22 manufacture over the next 25 yr is presented. Offered as a template rather than a prediction, this model projects current production practices and existing abatement frameworks to yield insights into how the atmosphere might evolve with and without additional efforts to constrain HFC-23 emissions.

    Assuming that no additional abatement measures are implemented, emissions for year 2035 in this Reference Case would rise to 24 ktonnes yr−1, (cf., 8.6 ktonnes yr−1 in 2009, the atmospheric abundance of HFC-23 would rise to 50 ppt, which is a 121 % increase over the 2009 observed abundance, and HFC-23 would be expected to contribute a radiative forcing of 9 mW m−2 (cf., 4 mW m−2 in 2009. Under such a scenario, the HFC-23 emission growth rate would be a continuation of the historical trend of ~0.2 ktonnes yr−2 until 2030, after which the growth is projected to quadruple as the Montreal Protocol phase-out of HCFC production for dispersive use concludes and HFC-23 thermal decomposition in the projects of the Clean Development Mechanism (CDM comes to a scheduled end while growth in the production of HCFC-22 for feedstock use continues to climb with projected GDP growth.

    Two opposite variations regarding the future renewal of CDM projects are examined for their impact on projected emissions and abundance, relative to the Reference Case scenario.

  3. Projecting future HFC-23 emissions

    Directory of Open Access Journals (Sweden)

    B. R. Miller

    2011-12-01

    Full Text Available A Reference Case (RC scenario for emissions of HFC-23 from co-production during HCFC-22 manufacture over the next 25 years is presented. Offered as a template rather than a prediction, this model projects current production practices and existing abatement frameworks to yield insights into how atmospheric composition and radiative forcing might change with and without additional efforts to constrain HFC-23 emissions.

    Assuming that no additional abatement measures are implemented, emissions for year 2035 in this Reference Case would rise to 24 ktonnes yr−1, (cf., 8.6 ktonnes yr−1 in 2009, the atmospheric abundance of HFC-23 would rise to 50 ppt, which is a 121 % increase over the 2009 observed abundance, and HFC-23 would be expected to contribute a radiative forcing of 9 mW m−2 (cf., 4 mW m−2 in 2009. Under such a scenario, the HFC-23 emission growth rate would be a continuation of the historical trend of ∼0.2 ktonnes yr−2 until 2030, after which the growth is projected to quadruple as the Montreal Protocol phase-out of HCFC production for dispersive use concludes and HFC-23 thermal decomposition in the projects of the Clean Development Mechanism (CDM comes to a scheduled end while growth in the production of HCFC-22 for feedstock use continues to climb with projected GDP growth.

    Two opposite variations regarding the future renewal of CDM projects are examined for their impact on projected emissions and abundance, relative to the Reference Case scenario.

  4. Gaseous emissions from waste combustion

    International Nuclear Information System (INIS)

    An overview is given on methods and technologies for limiting the gaseous emissions from waste combustion. With the guideline 2000/76/EC recent European legislation has set stringent limits not only for the mono-combustion of waste in specialized incineration plants but also for co-combustion in coal-fired power plants. With increased awareness of environmental issues and stepwise decrease of emission limits and inclusion of more and more substances into the network of regulations a multitude of emission abatement methods and technologies have been developed over the last decades. The result is the state-of-the-art waste incinerator with a number of specialized process steps for the individual components in the flue gas. The present work highlights some new developments which can be summarized under the common goal of reducing the costs of flue gas treatment by applying systems which combine the treatment of several noxious substances in one reactor or by taking new, simpler routes instead of the previously used complicated ones or - in the case of flue gas desulphurisation - by reducing the amount of limestone consumption. Cost reduction is also the driving force for new processes of conditioning of nonhomogenous waste before combustion. Pyrolysis or gasification is used for chemical conditioning whereas physical conditioning means comminution, classification and sorting processes. Conditioning yields a fuel which can be used in power plants either as a co-fuel or a mono-fuel and which will burn there under much better controlled conditions and therefore with less emissions than the nonhomogeneous waste in a conventional waste incinerator. Also for cost reasons, co-combustion of wastes in coal-fired power stations is strongly pressing into the market. Recent investigations reveal that the co-firing of waste can also have beneficial effects on the operating behavior of the boiler and on the gaseous emissions

  5. Gaseous emissions from waste combustion

    Energy Technology Data Exchange (ETDEWEB)

    Werther, Joachim [Hamburg University of Technology, Institute of Solids Process Engineering and Particle Technology, D 21071 Hamburg (Germany)]. E-mail: Werther@tuhh.de

    2007-06-18

    An overview is given on methods and technologies for limiting the gaseous emissions from waste combustion. With the guideline 2000/76/EC recent European legislation has set stringent limits not only for the mono-combustion of waste in specialized incineration plants but also for co-combustion in coal-fired power plants. With increased awareness of environmental issues and stepwise decrease of emission limits and inclusion of more and more substances into the network of regulations a multitude of emission abatement methods and technologies have been developed over the last decades. The result is the state-of-the-art waste incinerator with a number of specialized process steps for the individual components in the flue gas. The present work highlights some new developments which can be summarized under the common goal of reducing the costs of flue gas treatment by applying systems which combine the treatment of several noxious substances in one reactor or by taking new, simpler routes instead of the previously used complicated ones or - in the case of flue gas desulphurisation - by reducing the amount of limestone consumption. Cost reduction is also the driving force for new processes of conditioning of nonhomogenous waste before combustion. Pyrolysis or gasification is used for chemical conditioning whereas physical conditioning means comminution, classification and sorting processes. Conditioning yields a fuel which can be used in power plants either as a co-fuel or a mono-fuel and which will burn there under much better controlled conditions and therefore with less emissions than the nonhomogeneous waste in a conventional waste incinerator. Also for cost reasons, co-combustion of wastes in coal-fired power stations is strongly pressing into the market. Recent investigations reveal that the co-firing of waste can also have beneficial effects on the operating behavior of the boiler and on the gaseous emissions.

  6. Gaseous emissions from waste combustion.

    Science.gov (United States)

    Werther, Joachim

    2007-06-18

    An overview is given on methods and technologies for limiting the gaseous emissions from waste combustion. With the guideline 2000/76/EC recent European legislation has set stringent limits not only for the mono-combustion of waste in specialized incineration plants but also for co-combustion in coal-fired power plants. With increased awareness of environmental issues and stepwise decrease of emission limits and inclusion of more and more substances into the network of regulations a multitude of emission abatement methods and technologies have been developed over the last decades. The result is the state-of-the-art waste incinerator with a number of specialized process steps for the individual components in the flue gas. The present work highlights some new developments which can be summarized under the common goal of reducing the costs of flue gas treatment by applying systems which combine the treatment of several noxious substances in one reactor or by taking new, simpler routes instead of the previously used complicated ones or - in the case of flue gas desulphurisation - by reducing the amount of limestone consumption. Cost reduction is also the driving force for new processes of conditioning of nonhomogenous waste before combustion. Pyrolysis or gasification is used for chemical conditioning whereas physical conditioning means comminution, classification and sorting processes. Conditioning yields a fuel which can be used in power plants either as a co-fuel or a mono-fuel and which will burn there under much better controlled conditions and therefore with less emissions than the nonhomogeneous waste in a conventional waste incinerator. Also for cost reasons, co-combustion of wastes in coal-fired power stations is strongly pressing into the market. Recent investigations reveal that the co-firing of waste can also have beneficial effects on the operating behavior of the boiler and on the gaseous emissions. PMID:17339077

  7. Evaluation and improvement of road vehicle pollutant emission factors based on instantaneous emissions data processing

    OpenAIRE

    Franco García, Vicente

    2014-01-01

    Introduction Current instrumentation makes it possible to measure vehicle emissions with high temporal resolution. But the increased resolution of emissions signals does not equate with increased accuracy. A prerequisite for the derivation of accurate emission factors from instantaneous vehicle emissions data is a fine allocation of measured mass emissions to recorded engine or vehicle states. This poses a technical challenge, because vehicle emission test facilities are not designed to su...

  8. Emission monitor. 1999 and estimates for 2000

    International Nuclear Information System (INIS)

    This report summarizes the results of the Dutch Emission Inventory for the base year 1999 and presents preliminary emission data for 2000. Within the inventory for the base year all emissions to air and water from all sources in the Netherlands have been registered. All emission data have been collected in the national Pollutant Emission Register, which is actually the Dutch Pollutant Release and Transfer Register (PRTR), to monitor the progress of environmental policy. The results have been analysed with respect to pollutant, economic activity/sources and location resulting in contributions of target sectors to different environmental themes. Trends in emissions are presented by comparison with earlier years

  9. AIRFORCE. Aircraft emissions and radiative forcing from emissions

    Energy Technology Data Exchange (ETDEWEB)

    Meijer, E.W.; Kelder, H.; Velthoven, P.F.J. van; Wauben, W.M.F. [Royal Netherlands Meteorological Inst., De Bilt (Netherlands); Beck, J.P.; Velders, G.J.M. [National Inst. of Public Health and the Environment, Bilthoven (Netherlands); Lelieveld, J.; Scheeren, B.A. [Institute of Marine and Atmospheric Research Utrecht (Netherlands)

    1997-12-31

    The Dutch AIRFORCE project focuses on the effects of subsonic aircraft emissions on the chemical composition of the atmosphere and subsequent radiative forcing. It includes measurements in the tropopause region and the modelling of exhaust plumes and large-scale effects. An aircraft exhaust plume model has been developed to study plume processes. The results of the plume model are used in the global transport chemistry model CTMK to determine large-scale effects of plume processes. Due to the efficient conversion of NO{sub x} into HNO{sub 3} inside aircraft exhaust plumes, a decrease of about 25% of the O{sub 3} perturbation was found in the NAFC at 200 hPa in July. Measurements of hydrocarbons revealed a dominant role of the anthropogenic continental emissions of light hydrocarbons in the tropopause region. (author) 20 refs.

  10. Nitrous oxide emissions from light duty vehicles

    Science.gov (United States)

    Graham, Lisa A.; Belisle, Sheri L.; Rieger, Paul

    Nitrous oxide (N 2O) emissions measurements were made on light duty gasoline and light duty diesel vehicles during chassis dynamometer testing conducted at the Environment Canada and California Air Resources Board vehicle emissions laboratories between 2001 and 2007. Per phase and composite FTP emission rates were measured. A subset of vehicles was also tested using other driving cycles to characterize emissions as a function of different driving conditions. Vehicles were both new (composite N 2O emission factors for gasoline vehicles meeting emission standards more stringent than Tier 1 are substantially lower than those currently used by both Canada and the US for the 2005 inventories. N 2O emission factors from test cycles other than the FTP illustrate the variability of emission factors as a function of driving conditions. N 2O emission factors are shown to strongly correlate with NMHC/NMOG emission standards and less strongly with NO X and CO emission standards. A review of several published reports on the effect of gasoline sulfur content on N 2O emissions suggests that additional research is needed to adequately quantify the increase in N 2O emissions as a function of fuel sulfur.

  11. Simultaneous emission and transmission scanning in positron emission tomography

    International Nuclear Information System (INIS)

    Examination by PET (positron emission tomography) scanning, following the dosage of 2-deoxy-18F fluoro-D-glucose (FDG), is positively utilized for the diagnosis of cancers, rather than for the purpose of studies. This is because the examination by FDG-PET (PET scanning following the dosage of FDG) ensures higher efficiency in discrimination of cancers, than conventional CT and PET. The method of whole body scanning by PET scanning following the dosage of FDG is effectively utilized not only for discrimination cancers, but also for determining the degree of malignancy of tumors and evaluating the methods of treatment of cancers. In conventional methods for examining the degree of malignancy of tumors and evaluating the methods of cancer treatment, it is necessary to correct for the gamma-ray attenuation, which requires a longer time for examination, increasing the physical and psychological pains of the patients. We have installed the simultaneous emission and transmission scanning capability into the HEADTOME-V of the Shimadzu SET-2000W Series positron emission tomographic scanning instruments, to establish an instrument that permits FDG-PET whole body scanning in actual clinical fields, with minimized physical and psychological pains of patients concerned, yet ensuring an outstandingly high examination efficiency. This report also presents some data obtained by this newly developed instrument and those obtained in practical applications. (author)

  12. Isoprene emission from wetland sedges

    Directory of Open Access Journals (Sweden)

    A. Ekberg

    2009-04-01

    Full Text Available High latitude wetlands play an important role for the surface-atmosphere exchange of carbon dioxide (CO2 and methane (CH4, but fluxes of biogenic volatile organic compounds (BVOC in these ecosystems have to date not been extensively studied. This is despite BVOC representing a measurable proportion of the total gaseous C fluxes at northern locations and in the face of the high temperature sensitivity of these systems that requires a much improved process understanding to interpret and project possible changes in response to climate warming. We measured emission of isoprene and photosynthetic gas exchange over two growing seasons (2005–2006 in a subarctic wetland in northern Sweden with the objective to identify the physiological and environmental controls of these fluxes on the leaf scale. The sedge species Eriophorum angustifolium and Carex rostrata were both emitters of isoprene. Springtime emissions were first detected after an accumulated diurnal mean temperature above 0°C of about 100 degree days. Maximum measured growing season standardized (basal emission rates (20°C, 1000 μmol m−2 s−1 were 1075 (2005 and 1118 (2006 μg C m−2 (leaf area h−1 in E. angustifolium, and 489 (2005 and 396 (2006 μg C m−2 h−1 in C. rostrata. Over the growing season, basal isoprene emission varied in response to the temperature history of the last 48 h. Seasonal basal isoprene emission rates decreased with leaf nitrogen (N, which may be explained by the typical growth and resource allocation pattern of clonal sedges as the leaves age. The observations were used to model emissions over the growing season, accounting for effects of temperature history, links to leaf assimilation rate and the light and temperature dependencies of the cold-adapted sedges.

  13. Methane emissions from MBT landfills

    International Nuclear Information System (INIS)

    Highlights: • Compilation of methane generation potential of mechanical biological treated (MBT) municipal solid waste. • Impacts and kinetics of landfill gas production of MBT landfills, approach with differentiated half-lives. • Methane oxidation in the waste itself and in soil covers. • Estimation of methane emissions from MBT landfills in Germany. - Abstract: Within the scope of an investigation for the German Federal Environment Agency (“Umweltbundesamt”), the basics for the estimation of the methane emissions from the landfilling of mechanically and biologically treated waste (MBT) were developed. For this purpose, topical research including monitoring results regarding the gas balance at MBT landfills was evaluated. For waste treated to the required German standards, a methane formation potential of approximately 18–24 m3 CH4/t of total dry solids may be expected. Monitoring results from MBT landfills show that a three-phase model with differentiated half-lives describes the degradation kinetics in the best way. This is due to the fact that during the first years of disposal, the anaerobic degradation processes still proceed relatively intensively. In addition in the long term (decades), a residual gas production at a low level is still to be expected. Most of the soils used in recultivation layer systems at German landfills show a relatively high methane oxidation capacity up to 5 l CH4/(m2 h). However, measurements at MBT disposal sites indicate that the majority of the landfill gas (in particular at non-covered areas), leaves the landfill body via preferred gas emission zones (hot spots) without significant methane oxidation. Therefore, rather low methane oxidation factors are recommended for open and temporarily covered MBT landfills. Higher methane oxidation rates can be achieved when the soil/recultivation layer is adequately designed and operated. Based on the elaborated default values, the First Order Decay (FOD) model of the IPCC

  14. Natural wetland emissions of methylated trace elements

    NARCIS (Netherlands)

    Vriens, B.; Lenz, M.; Charlet, L.; Berg, M.; Winkel, L.H.E.

    2014-01-01

    Natural wetlands are well known for their significant methane emissions. However, trace element emissions via biomethylation and subsequent volatilization from pristine wetlands are virtually unstudied, even though wetlands constitute large reservoirs for trace elements. Here we show that the averag

  15. Single Photon Emission Computed Tomography (SPECT)

    Science.gov (United States)

    ... Tools & Resources Stroke More Single Photon Emission Computed Tomography (SPECT) Updated:Sep 11,2015 What is a ... Heart Attack Myocardial Perfusion Imaging (MPI) Positron Emission Tomography (PET) Radionuclide Ventriculography, Radionuclide Angiography, MUGA Scan Heart ...

  16. Compliance and Emissions Data Reporting Interface (CEDRI)

    Data.gov (United States)

    U.S. Environmental Protection Agency — EPA regulations codified in 40 CFR Part 60 and 63 require affected sources to perform emissions source tests, conduct continuous emissions monitoring, and submit...

  17. AP-42 Emissions Factors (WebFIRE)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Emissions factors have long been the fundamental tool in developing national, regional, state, and local emissions inventories for air quality management decisions...

  18. Photon emission within the linear sigma model

    CERN Document Server

    Wunderlich, F

    2015-01-01

    Soft-photon emission rates are calculated within the linear sigma model. The investigation is aimed at answering the question to which extent the emissivities map out the phase structure of this particular effective model of strongly interacting matter.

  19. Neural networks for NOx-emission

    International Nuclear Information System (INIS)

    The government wants to restrict nitrogen oxide emissions. However, continuous measurement of these emissions is expensive and maintenance-sensitive. A prediction model based on the use of neural networks might be a reliable and efficient alternative

  20. Characterisation of cement plant emissions in Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Ekinci, E.; Munlafalioglu, I.; Tiris, M.; Pekin, A.V. [Istanbul Technical University, Istanbul (Turkey). Chemical Engineering Dept.

    1998-08-01

    In cement plants in Turkey CO, NO{sub 2}, SO{sub 2} and particulate emissions were measured using standard measurement techniques and equipment. Emission factors are calculated by dividing the emission rates by capacity of production at the time of measurements for each plant. The results of this study show that the dominant emissions from cement production in Turkey is CO followed by NO{sub 2}, dust and SO{sub 2} in decreasing order. National averages for the emission factors are calculated and compared to international emission factors. On average the Turkish dust emission factor is higher than the German factor, however NO{sub 2} and SO{sub 2} emission factors are lower in Turkey. 7 refs., 2 figs., 7 tabs.

  1. Microwave Emission from Galactic Dust Grains

    CERN Document Server

    Draine, B T

    1999-01-01

    Observations of the cosmic microwave background have revealed a component of 10-60 GHz emission from the Galaxy which correlates with 100-140um emission from interstellar dust but has an intensity much greater than expected for the low-frequency tail of the "electric dipole vibrational" emission peaking at dust-correlated free-free emission. The anomalous emission could be due in part to magnetic dipole emission from thermal fluctuations of the magnetization within interstellar dust grains, but only if a substantial fraction of the Fe in interstellar dust resides in magnetic materials such as metallic iron or magnetite. The observed anomalous emission is probably due primarily to electric dipole radiation from spinning ultrasmall interstellar dust grains. This rotational emission is expected to be partially polarized. From the standpoint of minimizing confusion with non-CBR foregrounds, 60-120 GHz appears to be the optimal frequency window.

  2. Economywide effects of reducing CO2 emissions: A comparison between net and gross emissions

    International Nuclear Information System (INIS)

    In the paper, the economywide effects of setting emission limits on net emissions and on gross emissions from fossil fuels are compared, by using a computable general equilibrium model. Net emissions include carbon accumulating in forests, in addition to emissions from wood and fossil fuels. The forest owners are given an incentive to increase the amount of carbon in the forest, by taxing the emissions from wood. The efficient tax rate on emissions from wood is found to depend on the ability of export sectors to shift costs abroad. If the reduction of net emissions is small, it is efficient to reduce only the emissions from fossil fuels. On the other hand, when stabilizing the net emissions to the level of year 1990, nearly half of the emission reduction is achieved by increasing the carbon sink. The carbon tax that is needed to achieve the net emission level is clearly lower than the tax needed to stabilize gross emissions. However, there is only a minor difference between the welfare losses associated with stabilizing net emissions and stabilizing gross emissions. In most simulations, the net emission limit is more advantageous than gross emission limit 12 refs, 5 figs, 1 tab

  3. Climate, energy and emissions trading

    International Nuclear Information System (INIS)

    The authors question the 4 main concerns that have arisen since the implementation of emission trade markets 3 years ago. First, the allowance policy was not accurate enough and has led to a surplus offer of CO2 allowances. Secondly, the impact on electricity prices of carbon emission costs was all the higher as it happened at the moment of the deregulation of electricity markets. Thirdly, the CO2 allowances whose price will near 14 euros a ton for the 2008-2012 period are accused of hindering the competitiveness of the European industrial sector. Fourth, the present allowance system that gives to new comers free CO2 allowances is not very conducive to the adoption by these new comers of technologies that are less CO2 emitting. Some ways of improvement are given. (A.C.)

  4. Evaluation of Emissions Bio diesel

    International Nuclear Information System (INIS)

    The generation of energy from vegetal products is one of the possibilities to our reach in order to reduce the atmospheric pollution. Particularly, the use of bio diesel in internal combustion engines can be one of the best options. The finest particles emitted by the combustion engines are easily breathable and on them different substances can be absorbed presumably toxic, between which it is possible to emphasize the polycyclic aromatic hydrocarbons (PAHs), by its demonstrated carcinogen character. In this work, it is studied on the one hand, the characteristics that can present the aerosol of emission in a diesel engine with a maximum power of 97 kW, working without load to 600 rpm, using as combustible mixtures of bio diesel and diesel in different proportions. On the other hand, the evolution that takes place in the concentration of PAHs in emission particles, according to the percentage of bio diesel used in the combustible mixture. (Author) 9 refs

  5. Stimulated emission and black holes

    International Nuclear Information System (INIS)

    The probability of a black hole emitting m particles when n particles are incident on the black hole was first derived by Bekenstein and Meisels, and later, using a different method, by Panangaden and Wald. In another paper by Bekenstein, it was argued that black holes should have stimulated emission in all modes including the nonsuperradiant ones. In this paper, we use a model based on quantum field theory. We show that Bose-Einstein statistics enhances the probability for particles to scatter in the same direction. We also prove that a black hole is equivalent to a perfect blackbody surrounded by a mirror. In our model, the black hole does not exhibit stimulated emission in nonsuperradiant modes. We also compare the black hole to a gray body

  6. Evaluation of Emissions Bio diesel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Maroto, J. J.; Dorronsoro Arenal, J. L.; Rojas Garcia, E.; Perez Pastor, R.; Garcia Alonso, S.

    2007-09-27

    The generation of energy from vegetal products is one of the possibilities to our reach in order to reduce the atmospheric pollution. Particularly, the use of bio diesel in internal combustion engines can be one of the best options. The finest particles emitted by the combustion engines are easily breathable and on them different substances can be absorbed presumably toxic, between which it is possible to emphasize the polycyclic aromatic hydrocarbons (PAHs), by its demonstrated carcinogen character. In this work, it is studied on the one hand, the characteristics that can present the aerosol of emission in a diesel engine with a maximum power of 97 kW, working without load to 600 rpm, using as combustible mixtures of bio diesel and diesel in different proportions. On the other hand, the evolution that takes place in the concentration of PAHs in emission particles, according to the percentage of bio diesel used in the combustible mixture. (Author) 9 refs.

  7. Coronal Diagnostics from Cometary Emission

    Science.gov (United States)

    Bryans, Paul; Pesnell, William D; Seaton, Daniel B; West, Matthew J

    2014-06-01

    The extreme ultraviolet (EUV) emission observed from sungrazing comets as they pass through the solar atmosphere can be used to infer the properties of the corona. In this paper we will discuss several of these properties that can be estimated from the EUV observations of Comet Lovejoy from AIA/SDO and SWAP/PROBA2. The longevity of the emission allows us to constrain the coronal electron density through which the comet passes. We will also discuss how dispersion of the emitting cometary material we can be used to estimate the local Alfven speed in the corona. Finally, measuring the deformation of the magnetic field as it is impacted by the comet can be used to estimate the magnetic field strength in this location. In the absence of the comet, none of these parameters are directly measurable in the corona. Sungrazing comets are thus unique probes of the solar atmosphere.

  8. Pollutants emission in power sector

    International Nuclear Information System (INIS)

    Fossil fuels, including coal, natural gas, petroleum, shale oil and bitumen, are the primary source of heat and electrical energy production and are responsible for emitting a large number and amount of pollutants into the atmosphere via exhaust gases from industry, power stations, residential heating systems and vehicles. During the combustion process, different pollutants such as CO2, SOX (including SO2 and SO3), NOX (including NO2, NO and N2O), fly ash, VOCs and mercury are emitted. These emissions cause big environmental and human health hazard. CO2, N2O, some VOCs, CH4 contribute to the global greenhouse effect, adding a new dimension to the environmental degradation resulting from the burning of fossil fuels. These problems regarding emissions inventory, their impact on the environment and human health, air pollution control technologies and costs, periods of fossil fuels depletion, role of renewable and nuclear energy in the further civilization development are briefly discussed. (author)

  9. Spontaneous Emission in Nonlocal Materials

    CERN Document Server

    Ginzburg, Pavel; Nasir, Mazhar E; Olvera, Paulina Segovia; Krasavin, Alexey V; Levitt, James; Hirvonen, Liisa M; Wells, Brian; Suhling, Klaus; Richards, David; Podolskiy, Viktor A; Zayats, Anatoly V

    2016-01-01

    Light-matter interactions can be dramatically modified by the surrounding environment. Here we report on the first experimental observation of molecular spontaneous emission inside a highly nonlocal metamaterial based on a plasmonic nanorod assembly. We show that the emission process is dominated not only by the topology of its local effective medium dispersion, but also by the nonlocal response of the composite, so that metamaterials with different geometric parameters but the same local effective medium properties exhibit different Purcell factors. A record-high enhancement of a decay rate is observed, in agreement with the developed quantitative description of the Purcell effect in a nonlocal medium. An engineered material nonlocality introduces an additional degree of freedom into quantum electrodynamics, enabling new applications in quantum information processing, photo-chemistry, imaging, and sensing.

  10. Emission tax revenues in a growing economy

    OpenAIRE

    Pethig, Rüdiger

    1997-01-01

    This paper focuses on how emission tax revenues change relative to GNP, when a fixed environmental standard is implemented by an emission tax and when waste abatement, technical and structural change and capital accumulation is accounted for. One- and two-sector growth models are analyzed allowing for demand substitution and sectoral differences in emission intensities and elasticities of technical substitution. It turns out that the more difficult it is to reduce the emission of pollutants e...

  11. Field emission studies at Saclay and Orsay

    International Nuclear Information System (INIS)

    During the last five years, DC and RF equipment for field emission studies have been developed at Saclay and Orsay laboratories. Combining these devices, straight comparison has been carried out between DC and RF field emission from artificial emission sites on the same sample. Other topics are also reviewed: high field cleaning, plausible origins of thermal effects that occurred on emission sites in RF, behaviour of alumina particles under RF field, and optical observations and measurements. (author)

  12. EU polluting emissions: an empirical analysis

    OpenAIRE

    Álvarez, Francisco; Contestabile, M.; Gómez, C; Gustavo A. Marrero; Puch, Luis A.

    2016-01-01

    We provide an empirical study of the evolution of emissions of some specific air pollutants on a panel of EU member states from 1990 to 2000, and we relate observed patterns to macroeconomic performance. The ratio pollution emission to GDP, so-called emission intensity, has decreased over the period considered in most EU member states. However, a non-parametric analysis reveals that the relative positions of different countries in terms of GDP growth and reduction of emissions have remained b...

  13. Silicon Array for Multi-particle Emission

    Institute of Scientific and Technical Information of China (English)

    XU; Xin-xing; LIN; Cheng-jian; SUN; Li-jie; BAO; Peng-fei; YANG; Lei; YANG; Feng; ZHANG; Huan-qiao; LIU; Zu-hua; JIA; Hui-ming; MA; Nan-ru

    2013-01-01

    Remarkable progress in the study of two-proton emission has been made in recent years.One of the next destinations is the realization of high-precision direct measurements of decay-energy and emission-angle correlations inβ-delayed two-proton(β2p)emission.We have studiedβ2p correlated emission of the ground state of 26P at the proton drip line with the direct measurement at the National

  14. Dust Emissivity in the Far-Infrared

    OpenAIRE

    Bianchi, Simone; Davies, Jonathan I.; Alton, Paul B.

    1999-01-01

    We have derived the dust emissivity in the Far-Infrared (FIR) using data available in the literature. We use two wavelength dependences derived from spectra of Galactic FIR emission (Reach et al. 1995). A value for the emissivity, normalised to the extinction efficiency in the V band, has been retrieved from maps of Galactic FIR emission, dust temperature and extinction (Schlegel et al. 1998). Our results are similar to other measurements in the Galaxy but only marginally consistent with the ...

  15. The carbon emissions of Chinese cities

    OpenAIRE

    Wang, H.; Bi, J.; Zhang, R.; Liu, M.

    2012-01-01

    As increasing urbanization has become a national policy priority for economic growth in China, cities have become important players in efforts to reduce carbon emissions. However, their efforts have been hampered by the lack of specific and comparable carbon emission inventories. Comprehensive carbon emission inventories, which present both a relatively current snapshot and also show how emissions have changed over the past several years, of twelve Chinese cities were developed using ...

  16. The carbon emissions of Chinese cities

    OpenAIRE

    Wang, H.; Zhang, R.; Liu, M.; Bi, J.

    2012-01-01

    As increasing urbanization has become a national policy priority for economic growth in China, cities have become important players in efforts to reduce carbon emissions. However, their efforts have been hampered by the lack of specific and comparable carbon emission inventories. Comprehensive carbon emission inventories for twelve Chinese cities, which present both a relatively current snapshot and also show how emissions have changed over the past several years, were devel...

  17. Controlling nanowire emission profile using conical taper

    DEFF Research Database (Denmark)

    Gregersen, Niels; Nielsen, Torben Roland; Mørk, Jesper;

    2008-01-01

    The influence of a conical taper on nanowire light emission is studied. For nanowires with divergent output beams, the introduction of tapers improves the emission profile and increase the collection efficiency of the detection optics.......The influence of a conical taper on nanowire light emission is studied. For nanowires with divergent output beams, the introduction of tapers improves the emission profile and increase the collection efficiency of the detection optics....

  18. Methane Emissions from Icelandic Landfills

    OpenAIRE

    Guðrún Meyvantsdóttir 1982

    2014-01-01

    Landfilling of biodegradable organic waste results in the generation of methane, along with other gases. If the gas is not collected through a recovery system, it will migrate through pores in the landfill cover and be released into the atmosphere, where it contributes to the global greenhouse gas budget. This study presents the first direct measurements of CH4 emissions from Icelandic landfill surface-covers. The main objective was to obtain evidence on the occurrence and scale of CH4 emissi...

  19. Price floors for emissions trading

    OpenAIRE

    Wood, Peter John; Jotzo, Frank

    2009-01-01

    Price floors in greenhouse gas emissions trading schemes can have advantages for technological innovation, price volatility, and management of cost uncertainty. Implementing the schemes, however, has pitfalls. This research report argues that requiring firms to pay an extra fee or tax is the best way to put a price floor in place. As well as providing budgetary advantages, the fee approach is more compatible with international permit trading than the alternative approaches currently dominatin...

  20. Flare emission from Sagittarius A*

    Czech Academy of Sciences Publication Activity Database

    Eckart, A.; Garcia-Marin, M.; Vogel, S. N.; Teuben, P.; Morris, K.; Baganoff, F. K.; Dexter, J.; Schödel, R.; Witzel, G.; Valencia-S, M.; Karas, Vladimír; Kunneriath, Devaky; Bremer, M.; Straubmeier, C.; Moser, L.; Sabha, N.; Buchholz, R. M.; Zamaninasab, M.; Mužić, K.; Moultaka, J.; Zenus, J.A.

    Bristol: Institute of Physics Publishing, 2012, 012022/1-012022/13. (Journal of Physics Conference Series. 372). ISSN 1742-6588. [Astronomy at High Angular Resolution - The Central Kiloparsec in Galactic Nuclei. Bad Honnef (DE), 28.08.2011-02.09.2011] Grant ostatní: ESA(XE) ESA-PECS project No. 98040 Institutional research plan: CEZ:AV0Z10030501 Keywords : X-ray flare emission * Sagittarius A* * black hole Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  1. Positron emission tomography. Basic principles

    International Nuclear Information System (INIS)

    The basic principles of positron emission tomography (PET) technique are reviewed. lt allows to obtain functional images from gamma rays produced by annihilation of a positron, a positive beta particle. This paper analyzes positron emitters production in a cyclotron, its general mechanisms, and the various detection systems. The most important clinical applications are also mentioned, related to oncological uses of fluor-l8-deoxyglucose

  2. Gold emissivities for hydrocode applications

    Science.gov (United States)

    Bowen, C.; Wagon, F.; Galmiche, D.; Loiseau, P.; Dattolo, E.; Babonneau, D.

    2004-10-01

    The Radiom model [M. Busquet, Phys Fluids B 5, 4191 (1993)] is designed to provide a radiative-hydrodynamic code with non-local thermodynamic equilibrium (non-LTE) data efficiently by using LTE tables. Comparison with benchmark data [M. Klapisch and A. Bar-Shalom, J. Quant. Spectrosc. Radiat. Transf. 58, 687 (1997)] has shown Radiom to be inaccurate far from LTE and for heavy ions. In particular, the emissivity was found to be strongly underestimated. A recent algorithm, Gondor [C. Bowen and P. Kaiser, J. Quant. Spectrosc. Radiat. Transf. 81, 85 (2003)], was introduced to improve the gold non-LTE ionization and corresponding opacity. It relies on fitting the collisional ionization rate to reproduce benchmark data given by the Averroès superconfiguration code [O. Peyrusse, J. Phys. B 33, 4303 (2000)]. Gondor is extended here to gold emissivity calculations, with two simple modifications of the two-level atom line source function used by Radiom: (a) a larger collisional excitation rate and (b) the addition of a Planckian source term, fitted to spectrally integrated Averroès emissivity data. This approach improves the agreement between experiments and hydrodynamic simulations.

  3. Gold emissivities for hydrocode applications

    International Nuclear Information System (INIS)

    The Radiom model [M. Busquet, Phys Fluids B 5, 4191 (1993)] is designed to provide a radiative-hydrodynamic code with non-local thermodynamic equilibrium (non-LTE) data efficiently by using LTE tables. Comparison with benchmark data [M. Klapisch and A. Bar-Shalom, J. Quant. Spectrosc. Radiat. Transf. 58, 687 (1997)] has shown Radiom to be inaccurate far from LTE and for heavy ions. In particular, the emissivity was found to be strongly underestimated. A recent algorithm, Gondor [C. Bowen and P. Kaiser, J. Quant. Spectrosc. Radiat. Transf. 81, 85 (2003)], was introduced to improve the gold non-LTE ionization and corresponding opacity. It relies on fitting the collisional ionization rate to reproduce benchmark data given by the Averroes superconfiguration code [O. Peyrusse, J. Phys. B 33, 4303 (2000)]. Gondor is extended here to gold emissivity calculations, with two simple modifications of the two-level atom line source function used by Radiom: (a) a larger collisional excitation rate and (b) the addition of a Planckian source term, fitted to spectrally integrated Averroes emissivity data. This approach improves the agreement between experiments and hydrodynamic simulations

  4. Neutron emission prior to fission

    International Nuclear Information System (INIS)

    In recent years, many groups have measured neutrons and light charged particles in coincidence with fission fragments in heavy ion reactions. In most cases, particles emitted with an energy spectrum and angular distribution characteristic of that of compound nucleus evaporation have been measured in excess of statistical model predictions. They have chosen to investigate this effect in detail by studying neutron emission in the 158Er composite system. The advantage of this system is that it can be produced by a variety of projectile target combinations. They have chosen four combinations which form 158Er with similar critical angular momenta but varying excitation energy. The rationale is to form the same system with different neutron emission times; if the enhanced neutrons are being emitted during the fission process, the different emission time scales might possibly be used to time the fission process. In addition, they impose an additional constraint - that they have a significant fission barrier for most of the partial waves involved in the fission process. The reactions they have selected are 16O + 142Nd (207 MeV beam energy), 24Mg + 134Ba (180 MeV), 32S + 126Te (180 MeV), 50Ti + 108Pd (216 MeV)

  5. Trace element emissions from coal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-09-15

    Trace elements are emitted during coal combustion. The quantity, in general, depends on the physical and chemical properties of the element itself, the concentration of the element in the coal, the combustion conditions and the type of particulate control device used, and its collection efficiency as a function of particle size. Some trace elements become concentrated in certain particle streams following combustion such as bottom ash, fly ash, and flue gas particulate matter, while others do not. Various classification schemes have been developed to describe this partitioning behaviour. These classification schemes generally distinguish between: Class 1: elements that are approximately equally concentrated in the fly ash and bottom ash, or show little or no fine particle enrichment, examples include Mn, Be, Co and Cr; Class 2: elements that are enriched in the fly ash relative to bottom ash, or show increasing enrichment with decreasing particle size, examples include As, Cd, Pb and Sb; Class 3: elements which are emitted in the gas phase (primarily Hg (not discussed in this review), and in some cases, Se). Control of class 1 trace elements is directly related to control of total particulate matter emissions, while control of the class 2 elements depends on collection of fine particulates. Due to the variability in particulate control device efficiencies, emission rates of these elements can vary substantially. The volatility of class 3 elements means that particulate controls have only a limited impact on the emissions of these elements.

  6. Statistical modeling of global soil NOx emissions

    Science.gov (United States)

    Yan, Xiaoyuan; Ohara, Toshimasa; Akimoto, Hajime

    2005-09-01

    On the basis of field measurements of NOx emissions from soils, we developed a statistical model to describe the influences of soil organic carbon (SOC) content, soil pH, land-cover type, climate, and nitrogen input on NOx emission. While also considering the effects of soil temperature, soil moisture change-induced pulse emission, and vegetation fire, we simulated NOx emissions from global soils at resolutions of 0.5° and 6 hours. Canopy reduction was included in both data processing and flux simulation. NOx emissions were positively correlated with SOC content and negatively correlated with soil pH. Soils in dry or temperate regions had higher NOx emission potentials than soils in cold or tropical regions. Needleleaf forest and agricultural soils had high NOx emissions. The annual NOx emission from global soils was calculated to be 7.43 Tg N, decreasing to 4.97 Tg N after canopy reduction. Global averages of nitrogen fertilizer-induced emission ratios were 1.16% above soil and 0.70% above canopy. Soil moisture change-induced pulse emission contributed about 4% to global annual NOx emission, and the effect of vegetation fire on soil NOx emission was negligible.

  7. ANALYSIS OF EMISSIONS FROM RESIDENTIAL OIL FURNACES

    Science.gov (United States)

    The paper gives results of a series of emission tests on a residential oil furnace to determine emissions from two types of burners. umber of analyses were performed on the emissions, including total mass, filterable particulate, total oil furnaces tested by the EPA in Roanoke, V...

  8. 40 CFR 52.2309 - Emissions inventories.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Emissions inventories. 52.2309 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Texas § 52.2309 Emissions inventories. (a) The Governor of the State of Texas submitted the 1990 base year emission inventories for the...

  9. 40 CFR 52.384 - Emission inventories.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Emission inventories. 52.384 Section 52...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Connecticut § 52.384 Emission inventories. (a) The Governor's designee for the State of Connecticut submitted the 1990 base year emission inventories for...

  10. 40 CFR 52.348 - Emission inventories.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Emission inventories. 52.348 Section 52...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.348 Emission inventories. (a) The Governor of the State of Colorado submitted the 1990 carbon monoxide base year emission inventories for...

  11. 40 CFR 52.1036 - Emission inventories.

    Science.gov (United States)

    2010-07-01

    ... Implementation Plan (SIP). The 2002 base year emission inventory requirement of 40 CFR 51.915 has been satisfied... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Emission inventories. 52.1036 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Maine § 52.1036 Emission inventories. (a)...

  12. 40 CFR 52.2350 - Emission inventories.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Emission inventories. 52.2350 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Utah § 52.2350 Emission inventories. (a) The Governor of the State of Utah submitted the 1990 base year emission inventory of ozone precursors,...

  13. 40 CFR 52.1125 - Emission inventories.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Emission inventories. 52.1125 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Massachusetts § 52.1125 Emission inventories... emission inventories for the Springfield nonattainment area and the Massachusetts portion of the...

  14. 40 CFR 52.993 - Emissions inventories.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Emissions inventories. 52.993 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Louisiana § 52.993 Emissions inventories. (a) The Governor of the State of Louisiana submitted the 1990 base year emission inventories for the Baton...

  15. 40 CFR 52.1391 - Emission inventories.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Emission inventories. 52.1391 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Montana § 52.1391 Emission inventories. (a) The Governor of the State of Montana submitted the 1990 carbon monoxide base year emission...

  16. Characteristic emission in glutaraldehyde polymerized hemoglobin

    International Nuclear Information System (INIS)

    Hemoglobin with different modifications has been investigated using spectroscopic techniques. A new emission at around 371 nm has been observed under excitation of 305 nm from glutaraldehyde polymerized human hemoglobin. Intensity and peak position of the emission are dependent on both oxidation state and ligand environment and the emission has been identified from the hemoglobin oligomer.

  17. Competitiveness and linking of emission trading systems

    Energy Technology Data Exchange (ETDEWEB)

    Hausotter, Tobias; Steuwer, Sibyl; Taenzler, Dennis [adelphi, Berlin (Germany)

    2011-01-15

    The establishment of emission trading systems raises concerns among industries regarding international competitive disadvantages for the industries under an emissions cap. This study aims to assess competitiveness exposure of industrial sectors and presents policy measures to address these concerns. Moreover, the study provides a comparison of different existing approaches to competitiveness concerns proposed by regional emission trading systems. (orig.)

  18. 40 CFR 61.271 - Emission standard.

    Science.gov (United States)

    2010-07-01

    ... device requirements of 40 CFR 60.18. (3) The specifications and requirements listed in paragraphs (c)(1... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Emission standard. 61.271 Section 61...) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Benzene...

  19. 47 CFR 90.210 - Emission masks.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Emission masks. 90.210 Section 90.210... MOBILE RADIO SERVICES General Technical Standards § 90.210 Emission masks. Except as indicated elsewhere... emission masks outlined in this section. Unless otherwise stated, per paragraphs (d)(4), (e)(4), and (m)...

  20. 47 CFR 90.1323 - Emission limits.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Emission limits. 90.1323 Section 90.1323... MOBILE RADIO SERVICES Wireless Broadband Services in the 3650-3700 MHz Band § 90.1323 Emission limits. (a) The power of any emission outside a licensee's frequency band(s) of operation shall be...

  1. 47 CFR 27.53 - Emission limits.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Emission limits. 27.53 Section 27.53... COMMUNICATIONS SERVICES Technical Standards § 27.53 Emission limits. (a) For operations in the 2305-2320 MHz band and the 2345-2360 MHz band, the power of any emission outside a licensee's frequency band(s)...

  2. 47 CFR 22.357 - Emission types.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Emission types. 22.357 Section 22.357... Operational and Technical Requirements Technical Requirements § 22.357 Emission types. Any authorized station in the Public Mobile Services may transmit emissions of any type(s) that comply with the...

  3. Infrared emission from electronically excited biacetyl molecules

    NARCIS (Netherlands)

    Drent, E.; Kommandeur, J.

    1971-01-01

    The infrared emission of electronically excited biacetyl molecules in the gas phase at low pressure was observed. Some experimental details are given, and it is shown that the emission derives from biacetyl molecules in their triplet state. The emission is dependent on the wavelength of excitation.

  4. 47 CFR 90.669 - Emission limits.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Emission limits. 90.669 Section 90.669... 896-901/935-940 Mhz Band § 90.669 Emission limits. (a) On any frequency in an MTA licensee's spectrum block that is adjacent to a non-MTA frequency, the power of any emission shall be attenuated below...

  5. European emission trade starts in 2005

    International Nuclear Information System (INIS)

    At the end of 2002 the European Ministers of Environment agreed upon a mandatory emission trade system for European Union members. The system is planned to be implemented in 2005, and fits within the Kyoto Protocol of 1997 (i.e. 5% reduction of greenhouse gases emission for industrial countries). The opinions of two experts in the field of emission trade are reflected

  6. New Commitment Options: Compatibility with Emissions Trading

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    This paper considers different options for quantitative greenhouse gas emission commitments from the standpoint of their technical compatibility with emissions trading. These are dynamic targets, binding targets with price caps, non-binding targets, sector-wide targets/mechanisms, action targets, allowances and endowments, and long-term permits. This paper considers these options from the standpoint of their compatibility with emissions trading.

  7. Fugitive methane emissions from an agricultural biodigester

    International Nuclear Information System (INIS)

    The use of agricultural biodigesters provides a strategy for reducing greenhouse gas (GHG) emissions while generating energy. The GHG reduction associated with a biodigester will be affected by fugitive emissions from the facility. The objective of this study was to measure fugitive methane (CH4) emissions from a Canadian biodigester. The facility uses anaerobic digestion to produce biogas from cattle manure and other organic feedstock, which is burnt to generate electricity (1 MW capacity) and heat. An inverse dispersion technique was used to calculate emissions. Fugitive emissions were related to the operating state of the biodigester, and over four seasonal campaigns the emission rate averaged 3.2, 0.8, and 26.6 kg CH4 hr-1 for normal operations, maintenance, and flaring periods, respectively. During normal operations the average fugitive emission rate corresponded to 3.1% of the CH4 gas production rate. -- Highlights: → Biodigesters reduce greenhouse gas emissions. → Net emission reduction affected by fugitive emissions. → Fugitive CH4 measured at agricultural biodigester (1 MW generating capacity). → Emissions were 3.1% of gas production. → Emissions lower than assumed in carbon credit protocols.

  8. Review Existing and Proposed Emissions Trading Systems

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    This paper reviews key design features of mandatory emissions trading systems that had been established or were under consideration in 2010, with a particular focus on implications for the energy sector. Putting a price on greenhouse gas emissions is a cornerstone policy in climate change mitigation. To this end, many countries have implemented or are developing domestic emissions trading systems.

  9. Catalytic treatment of diesel engines, NOx emissions

    International Nuclear Information System (INIS)

    Some aspects of the operation of diesel engines are revised together with the pollutant emissions they produce, as well as the available catalytic technologies for the treatment of diesel emissions. Furthermore the performance of a catalyst developed in the environmental catalysis group for NOx reduction using synthetic gas mixtures simulating the emissions from diesel engines is presented

  10. An Instrument to Measure Aircraft Sulfate Particle Emissions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aircraft particle emissions contribute a modest, but growing, portion of the overall particle emissions budget. Characterizing aircraft particle emissions is...

  11. Light emission in tunneling processes

    International Nuclear Information System (INIS)

    We introduce a new method for mapping and analyzing (with atomic resolution) molecules adsorbed on surfaces. This method relies on the detection of fluorescence from molecules, electronically excited by inelastic tunneling in STM. It may combines the excellent spatial resolution of STM together with the specificity of fluorescence as an analytical tool. We propose to overcome this problem by choosing 'transparent conductors' (such as Indium Tin Oxides-lTO) as the STM substrate. ITO, characterized by a large optical gap, will not quench electronically excited molecules. We have tested our idea to enhance the quantum efficiency of molecular emission on surfaces by using transparent conductors in the tunneling junction. We have constructed large area tunnel-junctions by using the squeezable tunnel-Junction technique. The principle of this technique is to squeeze together smooth flat surfaces separated by a thin spacer. By applying a controlled force, junctions with surface area of thousands of square angstroms are made. We have recorded light emission from bare tunneling surfaces and from surfaces coated with molecules (DCA, DCM and COUMARINE), as a function of the bias voltage in the range of 0-5 volts. Typical tunneling currents are 50 nano ampere. Our main findings are: The bare ITO surface emits light at biasing voltages larger than 4.0 eV which corresponds to electron-hole excitation over the optical gap of ITO. ITO surfaces coated with chromophore molecules have shown enhanced light emission at a voltage bias which corresponds to the allowed excitations energies in the chromophore. A voltage bias of 2-5 V yielded light emission of 5 * 103 photon/μC. The corresponding metallic surfaces, bare or coated with a chromophore did not show any emission. In order to test the possibility of using this effect for imaging purposes we have replaced one electrode of junction with an ITO coated glass tip of 180 μm radius. such a tip yield an upper limit of tunneling area of

  12. Implications of diesel emissions control failures to emission factors and road transport NOx evolution

    Science.gov (United States)

    Ntziachristos, Leonidas; Papadimitriou, Giannis; Ligterink, Norbert; Hausberger, Stefan

    2016-09-01

    Diesel NOx emissions have been at the forefront of research and regulation scrutiny as a result of failures of late vehicle technologies to deliver on-road emissions reductions. The current study aims at identifying the actual emissions levels of late light duty vehicle technologies, including Euro 5 and Euro 6 ones. Mean NOx emission factor levels used in the most popular EU vehicle emission models (COPERT, HBEFA and VERSIT+) are compared with latest emission information collected in the laboratory over real-world driving cycles and on the road using portable emissions measurement systems (PEMS). The comparison shows that Euro 5 passenger car (PC) emission factors well reflect on road levels and that recently revealed emissions control failures do not call for any significant corrections. However Euro 5 light commercial vehicles (LCVs) and Euro 6 PCs in the 2014-2016 period exhibit on road emission levels twice as high as used in current models. Moreover, measured levels vary a lot for Euro 6 vehicles. Scenarios for future evolution of Euro 6 emission factors, reflecting different degree of effectiveness of emissions control regulations, show that total NOx emissions from diesel Euro 6 PC and LCV may correspond from 49% up to 83% of total road transport emissions in 2050. Unless upcoming and long term regulations make sure that light duty diesel NOx emissions are effectively addressed, this will have significant implications in meeting future air quality and national emissions ceilings targets.

  13. 40 CFR 60.36b - Emission guidelines for municipal waste combustor fugitive ash emissions.

    Science.gov (United States)

    2010-07-01

    ... combustor fugitive ash emissions. 60.36b Section 60.36b Protection of Environment ENVIRONMENTAL PROTECTION... September 20, 1994 § 60.36b Emission guidelines for municipal waste combustor fugitive ash emissions. For approval, a State plan shall include requirements for municipal waste combustor fugitive ash emissions...

  14. Thermal radio emission : The brightness temperature and the spectral index of radio emission

    OpenAIRE

    Prigara, F. V.

    2001-01-01

    The condition of radio emission is proposed, on the base of which the theory of themal radio emission for gaseous disk is developed. This theory explains the radio emission spectra of known types of extended radio sources, located beyond the Solar planetary system. Besides, the thermal radio emission spectra of Venus and Jupiter are explained.

  15. Five essays on emissions trading

    Energy Technology Data Exchange (ETDEWEB)

    Godal, Odd

    2005-03-01

    The thesis discusses energy, environmental and economic aspects of polluting emissions with emphasis on greenhouse gas trade and political measures. 5 papers are included with titles: 1) Carbon trading across sources and periods constrained by the Marrakesh Accords which examines examine the potential effects on permit prices and abatement costs of four compliance rules governing emissions trade across sources and periods in the Kyoto Protocol: The banking rule that allows excess permits to be used later; the restoration rate rule that penalizes borrowing; the commitment period reserve rule that limits sales; and finally, the suspension rule that restricts borrowing and sales. Our framework is a two-period model where parties may be out of compliance in the Kyoto period, but are assumed to comply at a later time. Under varying assumptions about market power and US participation, we find that the rules may have pronounced effects on individual costs, but overall efficiency is not severely affected. 2) Affine price expectations and equilibrium in strategic markets which considers equilibrium in imperfect markets, featuring agents who exchange property rights. Important cases include trade in emission permits of greenhouse gases, or exchange of catch quotas of fish. Some players act strategically while others are price-takers. The ''demand curve'' is endogenous, and it affects all parties. The resulting, reduced objectives need not be concave. Therefore, existence of equilibrium is a delicate matter. To simplify things, and to ensure availability of ''equilibria up to first order'', we presume that all strategic agents form affine price expectations. 3) Greenhouse gases, quota exchange and oligopolistic competition that discusses the problem how quotas can be shared in the ''emissions market'' and how can the agents reach as overall equilibrium in the product market. 4) Strategic markets in property rights

  16. Laser-induced ultrafast electron emission from a field emission tip

    CERN Document Server

    Barwick, B; Chandler-Smith, N; Corder, C; Strohaber, J; Uiterwaal, C; Barwick, Brett; Batelaan, Herman; Chandler-Smith, Nate; Corder, Chris; Strohaber, James; Uiterwaal, Cornelis

    2007-01-01

    We show that a field emission tip electron source that is triggered with a femtosecond laser pulse can generate electron pulses shorter than the laser pulse duration (~100 fs). The emission process is sensitive to a power law of the laser intensity, which supports an emission mechanism based on multiphoton absorption followed by over-the-barrier emission. Observed continuous transitions between power laws of different orders are indicative of field emission processes. We show that the source can also be operated so that thermionic emission processes become significant. Understanding these different emission processes is relevant for the production of sub-cycle electron pulses.

  17. Activation of silicon quantum dots for emission

    Institute of Scientific and Technical Information of China (English)

    Huang Wei-Qi; Miao Xin-Jian; Huang Zhong-Mei; Liu Shi-Rong; Qin Chao-Jian

    2012-01-01

    The emission of silicon quantum dots is weak when their surface is passivated well. Oxygen or nitrogen on the surface of silicon quantum dots can break the passivation to form localized electronic states in the band gap to generate active centers where stronger emission occurs.From this point of view,we can build up radiative matter for emission.Emissions of various wavelengths can be obtained by controlling the surface bonds of silicon quantum dots.Our experimental results demonstrate that annealing is important in the treatment of the activation,and stimulated emissions at about 600 and 700 nm take place on active silicon quantum dots.

  18. Emission guidelines for energy production from biomass

    International Nuclear Information System (INIS)

    For the introduction of bio-energy on the Dutch market it is important to know the regulations for the emission limits for the use of biomass. An overview is made of emission regulations in the Netherlands with respect to thermal conversion of biomass. Also experiences of practical situations have been compiled and evaluated and an inventory was made of emission regulations in Germany, Finland, Denmark, England and Austria and the European Union. All the compiled information has been evaluated and the Dutch emission regulations for bio-energy is represented in the form of a decision making scheme or working paper and compared with emission regulations in foreign countries. 18 refs

  19. Two-Photon Emission from Semiconductors

    CERN Document Server

    Hayat, A; Hayat, Alex; Orenstein, Meir

    2007-01-01

    We report, to the best of our knowledge, the first experimental observation of spontaneous two-photon emission from semiconductors. The overall two-photon emission power is only 4 orders of magnitude smaller than the fundamental one-photon emission power due to the continuous energy band structure of semiconductors. The measured wide-band two-photon emission spectrum is surprisingly blue-shifted in contrast to the two-photon emission from discrete-level atomic systems. This shift can be accounted for by the second-order matrix element k-dependence in semiconductors and the measured spectrum shape appears to be in good agreement with our calculations.

  20. Estimation of vegetative mercury emissions in China

    Institute of Scientific and Technical Information of China (English)

    QUAN Jiannong; ZHANG Xiaoshan; Shang Gyoo SHIM

    2008-01-01

    Vegetative mercury emissions were estimated within the framework of Biogenic Emission Inventory System (BEIS3 V3.11). In this estimation, the 19 categories of U.S. Geological Survey landcover data were incorporated to generate the vegetation-specific mercury emissions in a 81-km Lambert Conformal model grid coveting the total Chinese continent. The surface temperature and cloud-corrected solar radiation from a Mesoscale Meteorological model (MMS) were retrieved and used for calculating the diurnal variation. The implemented emission factors were either evaluated from the measured mercury flux data for forest, agriculture and water, or assumed for other land fields without available flux data. Annual simulations using the MM5 data were performed to investigate the seasonal emission variation. From the sensitivity analysis using two sets of emission factors, the vegetative mercury emissions in China domain were estimated to range from a lower limit of 79×103 kg/year to an upper limit of 177×103 kg/year. The modeled vegetative emissions were mainly generated from the eastern and southern China. Using the estimated data, it is shown that mercury emissions from vegetation are comparable to that from anthropogenic sources during summer. However, the vegetative emissions decrease greatly during winter, leaving anthropogenic sources as the major sources of emission.

  1. On the mechanism of fission neutron emission

    International Nuclear Information System (INIS)

    This review represents the present knowledge of the mechanism of prompt fission neutron emission. Starting with a brief fission process characterization related with neutron emission, possible emission mechanisms are discussed. It is emphasized that the experimental study of special mechanisms, i.e. scission neutron emission processes, requires a sufficiently correct description of emission probabilities on the base of the main mechanism, i.e. the evaporation from fully accelerated fragments. Adequate statistical-model approaches have to account for the complexity of nuclear fission reflected by an intricate fragment distribution. The present picture of scission neutron emission is not clarified neither experimentally nor theoretically. Deduced data are contradictory and depend on the used analysis procedures often involving rough discriptions of evaporated-neutron distributions. The contribution of two secondary mechanisms of fission neutron emission, i.e. the neutron evaporation during fragment acceleration and neutron emission due to the decay of 5He after ternary fission, is estimated. We summarize the recent progress of the theoretical description of fission neutron spectra in the framework of statistical models considering the standard spectrum of 252Cf(sf) neutrons especially. The main experimental basis for the study of fission neutron emission is the accurate measurement of emission probabilities as a function of emission energy and angle (at least) as well as fragment parameters (mass number ratio and kinetic energy). The present status is evaluated. (author)

  2. Mitigating greenhouse gas emissions: Voluntary reporting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-01

    The Voluntary Reporting Program, developed pursuant to Section 1605(b) of the Energy Policy Act of 1992, permits corporations, government agencies, households, and voluntary organizations to report on their emissions of greenhouse gases, and on actions taken that have reduced or avoided emissions or sequestered carbon, to the Energy Information Administration (EIA). This, the second annual report of the Voluntary Reporting Program, describes information provided by the participating organizations on their aggregate emissions and emissions reductions, as well as their emissions reduction or avoidance projects, through 1995. This information has been compiled into a database that includes reports from 142 organizations and descriptions of 967 projects that either reduced greenhouse gas emissions or sequestered carbon. Fifty-one reporters also provided estimates of emissions, and emissions reductions achieved, for their entire organizations. The projects described actions taken to reduce emissions of carbon dioxide from energy production and use; to reduce methane and nitrous oxide emissions from energy use, waste management, and agricultural processes; to reduce emissions of halocarbons, such as CFCs and their replacements; and to increase carbon sequestration.

  3. The EU Emission Trading Scheme. Sectoral Allocation Patterns and Factors Determining Emission Changes

    OpenAIRE

    Kettner, Claudia; Kletzan-Slamanig, Daniela; Köppl, Angela

    2013-01-01

    The EU Emission Trading Scheme (EU ETS) that covers emitters from industry and energy supply representing 40 percent of the EU's greenhouse gas emissions is the biggest implementation of a cap-and-trade scheme worldwide. In this paper, we analyse sectoral allocation caps focusing on three emission intensive sectors ("power and heat", "cement and lime", "pulp and paper"), assess the development of emissions and discuss the main drivers for emissions in these sectors since the start of the EU E...

  4. Air emissions inventory for the Idaho National Engineering Laboratory -- 1995 emissions report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    This report presents the 1995 update of the Air Emission Inventory for the Idaho National Engineering Laboratory (INEL). The INEL Air Emission Inventory documents sources and emissions of non-radionuclide pollutants from operations at the INEL. The report describes the emission inventory process and all of the sources at the INEL, and provides non-radionuclide emissions estimates for stationary sources. The air contaminants reported include nitrogen oxides, sulfur oxides, carbon monoxide, volatile organic compounds, particulates, and hazardous air pollutants (HAPs).

  5. Laser-induced ultrafast electron emission from a field emission tip

    OpenAIRE

    Barwick, Brett; Corder, Chris; Strohaber, James; Chandler-Smith, Nate; Uiterwaal, Cornelis; Batelaan, Herman

    2007-01-01

    We show that a field emission tip electron source that is triggered with a femtosecond laser pulse can generate electron pulses shorter than the laser pulse duration (~100 fs). The emission process is sensitive to a power law of the laser intensity, which supports an emission mechanism based on multiphoton absorption followed by over-the-barrier emission. Observed continuous transitions between power laws of different orders are indicative of field emission processes. We show that the source ...

  6. Air emissions inventory for the Idaho National Engineering Laboratory -- 1995 emissions report

    International Nuclear Information System (INIS)

    This report presents the 1995 update of the Air Emission Inventory for the Idaho National Engineering Laboratory (INEL). The INEL Air Emission Inventory documents sources and emissions of non-radionuclide pollutants from operations at the INEL. The report describes the emission inventory process and all of the sources at the INEL, and provides non-radionuclide emissions estimates for stationary sources. The air contaminants reported include nitrogen oxides, sulfur oxides, carbon monoxide, volatile organic compounds, particulates, and hazardous air pollutants (HAPs)

  7. EU-Type Carbon Emissions Trade and the Distributional Impact of Overlapping Emissions Taxes

    OpenAIRE

    Eichner, Thomas; Pethig, Rüdiger

    2009-01-01

    The European Union fulfills its emissions reductions commitments by means of an emissions trading scheme covering some part of each member state's economy and by national emissions control in the rest of their economies. The member states also levy energy/emissions taxes overlapping with the trading scheme. Restricting our focus on cost-effective policies, this paper investigates the distributive consequences of increasing the overlapping emissions tax that is uniform across countries. For qu...

  8. International Differences in Emissions Intensity and Emissions Content of Global Trade

    OpenAIRE

    Stratford Douglas; Shuichiro Nishioka

    2009-01-01

    Understanding international differences in the emissions intensity of trade and production is essential to understanding the effects of greenhouse gas limitation policies. We develop data on emissions from 48 industrial sectors in 32 countries and estimate the CO2 emissions intensity of production and trade. We find no evidence that developing countries specialize in emissions-intensive sectors; instead, emissions intensities differ systematically across countries because of differences in pr...

  9. Danish emission inventories for stationary combustion plants

    DEFF Research Database (Denmark)

    Nielsen, M.; Illerup, J. B.

    Emission inventories for stationary combustion plants are presented and the methodologies and assumptions used for the inventories are described. The pollutants considered are SO2, NOX, NMVOC, CH4, CO, CO2, N2O, particulate matter, heavy metals, dioxins and PAH. Since 1990 the fuel consumption in...... decrease of the SO2, NOX and heavy metal emissions is mainly a result of decreased emissions from large power plants and waste incineration plants. The greenhouse gas emission has decreased 1,3% since 1990. The emission of CH4, however, has increased due to increased use of lean-burn gas engines in CHP...... plants. The emission of PAH increased as a result of the increased combustion of wood in residential boilers and stoves. Uncertainties for the emissions and trends have been estimated...

  10. Danish emission inventories for stationary combustion plants

    DEFF Research Database (Denmark)

    Nielsen, M.; Illerup, J. B.

    Emission inventories for stationary combustion plants are presented and the methodologies and assumptions used for the inventories are described. The pollutants considered are: SO2, NOx, NMVOC, CH4, CO, CO2, N2O, particulate matter, heavy metals, dioxins and PAH. Since 1990 the fuel consumption in...... decrease of the SO2, NOx and heavy metal emissions is mainly a result of decreased emissions from large power plants and waste incineration plants. The greenhouse gas emission has decreased 1,5% since 1990. The emission of CH4, however, has increased due to increased use of lean-burn gas engines in CHP...... plants. The emission of PAH increased as a result of the increased combustion of wood in residential boilers and stoves. Uncertainties for the emissions and trends have been estimated....

  11. Thermal emission by a subwavelength aperture

    Science.gov (United States)

    Joulain, Karl; Ezzahri, Younès; Carminati, Rémi

    2016-04-01

    We calculate, by means of fluctuational electrodynamics, the thermal emission of an aperture separating from the outside, vacuum or a material at temperature T. We show that thermal emission is very different whether the aperture size is large or small compared to the thermal wavelength. Subwavelength apertures separating vacuum from the outside have their thermal emission strongly decreased compared to classical blackbodies which have an aperture much larger than the wavelength. A simple expression of their emissivity can be calculated and their total emissive power scales as T8 instead of T4 for large apertures. Thermal emission of disk of materials with a size comparable to the wavelength is also discussed. It is shown in particular that emissivity of such a disk is increased when the material can support surface waves such as phonon polaritons.

  12. Emissions from tropical hydropower and the IPCC

    International Nuclear Information System (INIS)

    Highlights: • Tropical dams emit greenhouse gases, which are undercounted in IPCC guidelines. • IPCC comparisons with other energy sources undercount hydroelectric emissions. • GHG inventories must fully count emissions as a basis for negotiating national quotas. • The IPCC needs to reassess emissions from dams independent of the hydropower industry. - Abstract: Tropical hydroelectric emissions are undercounted in national inventories of greenhouse gases under the United Nations Framework Convention on Climate Change (UNFCCC), giving them a role in undermining the effectiveness of as-yet undecided emission limits. These emissions are also largely left out of the Intergovernmental Panel on Climate Change (IPCC) Special Report on Renewable Energy Sources and Climate Change Mitigation, and have been excluded from a revision of the IPCC guidelines on wetlands. The role of hydroelectric dams in emissions inventories and in mitigation has been systematically ignored

  13. Mitigate emissions of Ammonia from Nitrogen fertilizers

    International Nuclear Information System (INIS)

    Ammonia emissions are one of the main causes of acidification and eutrophication processes, and one of the most important contributors to the formation of secondary PM. The European NEC Directive 2001/81/CE introduced compulsory national emission ceiling for different pollutants and fixed for each countries a national ceiling for ammonia emissions to be reached in 2010. Agriculture plays a crucial role by emitting more than 90% of the total ammonia emissions. The main sources are livestock and fertilizer uses. In our activities we have studied the effects of different strategies to reduce Nitrogen fertilizer use and specifically Urea in Italy at the year 2010 and 2020. Different measures and techniques have been evaluated to estimate their effects as a potential options to mitigate emissions: fertilization, controlled release of fertilizers and biological agriculture. Each one of this option has been evaluated in terms of NH3 emission abatement showing that they could together provide good result in reducing ammonia air emission

  14. China's regional CO2 emissions: Characteristics, inter-regional transfer and emission reduction policies

    International Nuclear Information System (INIS)

    This paper analyzes the characteristics of China's regional CO2 emissions and effects of economic growth and energy intensity using panel data from 1997 to 2009. The results show that there are remarkable regional disparities among eastern, central and western areas, regional elasticities of per capita GDP and energy intensity on CO2 emissions, which reflect the regional differences in economic development, economy structure and restraining function of energy intensity decrease on the emission. Energy intensity reducing is more effective to emission abatement for provinces with higher elasticity of energy intensity, but may not be significant for provinces with lower elasticity. The inverse distribution of energy production and consumption, regional unfairness caused by institutional factors like energy price and tax system result in inter-regional CO2 emission transfer embodied in the power transmission. The calculation indicates that the embodied emission transfer was gradually significant after 2003, from eastern area to the central and western areas, especially energy production provinces in central area, which leads to distortion on the emission and emission intensity. The regional emission reduction targets and supporting policies should be customized and consistent with the actual situations rather than setting the same target for all the provinces. - Highlights: → We analyze growth trend and spatial distribution of China's regional CO2 emission. → Elasticities of GDP and energy intensity have diverse effects on regional emission. → There is inter-regional emission transfer embodied in the power transmission. → The emission transfer makes distortion of regional emission and emission intensity.

  15. Inventories and scenarios of nitrous oxide emissions

    Science.gov (United States)

    Davidson, Eric A.; Kanter, David

    2014-10-01

    Effective mitigation for N2O emissions, now the third most important anthropogenic greenhouse gas and the largest remaining anthropogenic source of stratospheric ozone depleting substances, requires understanding of the sources and how they may increase this century. Here we update estimates and their uncertainties for current anthropogenic and natural N2O emissions and for emissions scenarios to 2050. Although major uncertainties remain, ‘bottom-up’ inventories and ‘top-down’ atmospheric modeling yield estimates that are in broad agreement. Global natural N2O emissions are most likely between 10 and 12 Tg N2O-N yr-1. Net anthropogenic N2O emissions are now about 5.3 Tg N2O-N yr-1. Gross anthropogenic emissions by sector are 66% from agriculture, 15% from energy and transport sectors, 11% from biomass burning, and 8% from other sources. A decrease in natural emissions from tropical soils due to deforestation reduces gross anthropogenic emissions by about 14%. Business-as-usual emission scenarios project almost a doubling of anthropogenic N2O emissions by 2050. In contrast, concerted mitigation scenarios project an average decline of 22% relative to 2005, which would lead to a near stabilization of atmospheric concentration of N2O at about 350 ppb. The impact of growing demand for biofuels on future projections of N2O emissions is highly uncertain; N2O emissions from second and third generation biofuels could remain trivial or could become the most significant source to date. It will not be possible to completely eliminate anthropogenic N2O emissions from agriculture, but better matching of crop N needs and N supply offers significant opportunities for emission reductions.

  16. Inventories and scenarios of nitrous oxide emissions

    International Nuclear Information System (INIS)

    Effective mitigation for N2O emissions, now the third most important anthropogenic greenhouse gas and the largest remaining anthropogenic source of stratospheric ozone depleting substances, requires understanding of the sources and how they may increase this century. Here we update estimates and their uncertainties for current anthropogenic and natural N2O emissions and for emissions scenarios to 2050. Although major uncertainties remain, ‘bottom-up’ inventories and ‘top-down’ atmospheric modeling yield estimates that are in broad agreement. Global natural N2O emissions are most likely between 10 and 12 Tg N2O-N yr−1. Net anthropogenic N2O emissions are now about 5.3 Tg N2O-N yr−1. Gross anthropogenic emissions by sector are 66% from agriculture, 15% from energy and transport sectors, 11% from biomass burning, and 8% from other sources. A decrease in natural emissions from tropical soils due to deforestation reduces gross anthropogenic emissions by about 14%. Business-as-usual emission scenarios project almost a doubling of anthropogenic N2O emissions by 2050. In contrast, concerted mitigation scenarios project an average decline of 22% relative to 2005, which would lead to a near stabilization of atmospheric concentration of N2O at about 350 ppb. The impact of growing demand for biofuels on future projections of N2O emissions is highly uncertain; N2O emissions from second and third generation biofuels could remain trivial or could become the most significant source to date. It will not be possible to completely eliminate anthropogenic N2O emissions from agriculture, but better matching of crop N needs and N supply offers significant opportunities for emission reductions. (paper)

  17. Modeling of pesticide emissions from agricultural ecosystems

    Science.gov (United States)

    Li, Rong

    2012-04-01

    Pesticides are applied to crops and soils to improve agricultural yields, but the use of pesticides has become highly regulated because of concerns about their adverse effects on human health and environment. Estimating pesticide emission rates from soils and crops is a key component for risk assessment for pesticide registration, identification of pesticide sources to the contamination of sensitive ecosystems, and appreciation of transport and fate of pesticides in the environment. Pesticide emission rates involve processes occurring in the soil, in the atmosphere, and on vegetation surfaces and are highly dependent on soil texture, agricultural practices, and meteorology, which vary significantly with location and/or time. To take all these factors into account for simulating pesticide emissions from large agricultural ecosystems, this study coupled a comprehensive meteorological model with a dynamic pesticide emission model. The combined model calculates hourly emission rates from both emission sources: current applications and soil residues resulting from historical use. The coupled modeling system is used to compute a gridded (36 × 36 km) hourly toxaphene emission inventory for North America for the year 2000 using a published U.S. toxaphene residue inventory and a Mexican toxaphene residue inventory developed using its historical application rates and a cropland inventory. To my knowledge, this is the first such hourly toxaphene emission inventory for North America. Results show that modeled emission rates have strong diurnal and seasonal variations at a given location and over the entire domain. The simulated total toxaphene emission from contaminated agricultural soils in North America in 2000 was about 255 t, which compares reasonably well to a published annual estimate. Most emissions occur in spring and summer, with domain-wide emission rates in April, May and, June of 36, 51, and 35 t/month, respectively. The spatial distribution of emissions depends

  18. Acoustic Emission Stethoscope - Measurements with Acoustic Emission on Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Krystof Kryniski [AaF Infrastructure, Stockholm (Sweden)

    2013-02-15

    A remote ultrasonic stethoscope, designed on mobile devices to help a maintenance team in diagnosing drive train problems, has been demonstrated. By implementing an acoustic emission technology, the operating conditions of wind turbines have been assessed by trending techniques and ultrasonic acoustic emission converted into audible sound. The new approach has been developed and tested and compared to other monitoring techniques. Acoustic emission has generally been shown to provide a number of advantages over vibration and shock pulse methods because the system is operating in a substantially higher frequency range (100 kHz) and therefore it is more immune to operation of surrounding machines and components. Quick attenuation of ultrasonic propagation waves in the drive-train structure helps to pin-point the origin of any fault as the signals are sharper and more pronounced. Further, with the intensity measurements a direction of the source of ultrasonic energy can be identified. Using a high frequency thus makes the method suitable for measuring local effects and to determine local defects since the disturbing signals from other parts are damped. Recently developed programmable sensors capable of processing signals onboard, producing quality outputs with extremely low noise-to-signal ratio, have been used. It is discussed how the new approach can lower the cost of a wind-turbine monitoring system, while at the same time making it simple and more reliable, see Appendix A. The method has been tested on rotating parts of wind-turbines, including traditionally difficult areas such as low speed main bearings and planetary gearboxes. The method developed in the project was designed to see physical processes such as friction, impacts and metal removal, occurring when machinery degrades, can be detected and notified with the developed notification system. Apart from reporting the status and displaying the changes of the pre-defined parameters or symptoms, the system has

  19. Trace element emissions. Literature review

    International Nuclear Information System (INIS)

    Application of fossil fuels by various utilities results in the emission of trace elements to air, water and solid waste streams. Elements present in coal are released as particles or as vapours during coal combustion or gasification. Owing to the increased consumption of coal, especially for power generation, huge quantities of potentially hazardous trace elements are released into the atmosphere every year. It is necessary to evaluate the emissions of each trace element from coal-fired combustion or gasification systems, and their effects on the environment. Present research interests should be aimed at determining the sources, concentrations, and environmental impact of trace elements related with energy generation and relevant control technologies. Two of the emerging advanced coal gasification technologies, such as integrated gasification combined cycle (IGCC) and integrated gasification fuel cell (IGFC) are presently experiencing potential difficulties due to trace element emissions. In order to control the levels of these contaminants within regulatory limits and to ensure the efficient operation of fuel cells, it is necessary to determine the type and quantity of trace elements emitted from coal gasification-based systems as a function of system, operating conditions, and type of coal. The partitioning of the trace elements is influenced by the gasification conditions. In general, the following gasification conditions are expected to influence the distribution of trace elements between various product streams. (a) reducing and oxidizing environments (b) gas phase composition, pressure and temperature. The present report was aimed at finding and identifying gaps existing in the literature on the trace element transformations during gasification. Also included in the report is the modelling of relevant transformation mechanisms of the trace elements during gasification as a function of coal type and process conditions. 7 figs., 6 tabs., 69 refs

  20. Learning from global emissions scenarios

    International Nuclear Information System (INIS)

    Scenarios of global greenhouse gas emissions have played a key role in climate change analysis for over twenty years. Currently, several research communities are organizing to undertake a new round of scenario development in the lead-up to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). To help inform this process, we assess a number of past efforts to develop and learn from sets of global greenhouse gas emissions scenarios. We conclude that while emissions scenario exercises have likely had substantial benefits for participating modeling teams and produced insights from individual models, learning from the exercises taken as a whole has been more limited. Model comparison exercises have typically focused on the production of large numbers of scenarios while investing little in assessing the results or the production process, perhaps on the assumption that later assessment efforts could play this role. However, much of this assessment potential remains untapped. Efforts such as scenario-related chapters of IPCC reports have been most informative when they have gone to extra lengths to carry out more specific comparison exercises, but in general these assessments do not have the remit or resources to carry out the kind of detailed analysis of scenario results necessary for drawing the most useful conclusions. We recommend that scenario comparison exercises build-in time and resources for assessing scenario results in more detail at the time when they are produced, that these exercises focus on more specific questions to improve the prospects for learning, and that additional scenario assessments are carried out separately from production exercises. We also discuss the obstacles to better assessment that might exist, and how they might be overcome. Finally, we recommend that future work include much greater emphasis on understanding how scenarios are actually used, as a guide to improving scenario production.

  1. Electromagnetic emissions during rock blasting

    Science.gov (United States)

    O'Keefe, S. G.; Thiel, D. V.

    1991-05-01

    Radio emissions during quarry blasting have been recorded in the audio frequency band. Three distinct mechanisms are suggested to explain the observed results; rock fracture at the time of the explosion, charged rocks discharging on impact with the pit floor and micro-fracture of the remaining rock wall due to pressure adjustment of the bench behind the blast. The last mechanism was evident by a train of discrete impulses recorded for up to one minute after the blast. It is assumed that during this time the rock behind the blast was subjected to a significant change in pressure. This may be related to ELF observations during earthquakes.

  2. Emissivity Measurement of Semitransparent Textiles

    OpenAIRE

    Ferrarini, G.; G. Cadelano; A. Bortolin; P. Bison; Grinzato, E.

    2012-01-01

    In the textiles production industry it is more and more common to advertise new textiles, especially for sportswear, by claiming their ability to emit IR radiation in the long wave band at a higher degree with respect to normal clothes, that is highly beneficial to improve sporting performances. Three textiles are compared, one normal and two “special,” with Ag+ ions and carbon powder added, with different colors. The emissivity of the textiles has been measured to determine if it is increase...

  3. Apparatus for measuring radioactive emissions

    International Nuclear Information System (INIS)

    Apparatus for measuring radioactive emissions from moving radioactive material comprises at least one radiation detector in a housing serving as a first radiation shield and in which at least one groove is formed to expose at least a portion of a receptor surface of the detector. The groove extends transverse to the direction of movement of the material over the detector. A second radiation shield may be located between at least a portion of the first shield and the detector. The material of the second shield is inherently less contaminated and emits secondary excitation radiation of lower energy than the first material. (author)

  4. Fundamentals of positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography is a modern radionuclide method of measuring physiological quantities or metabolic parameters in vivo. The methods is based on: (1) Radioactive labelling with positron emitters; (2) the coincidence technique for the measurement of the annihilation radiation following positron decay; (3) analysis of the data measured using biological models. The basic aspects and problems of the method are discussed. The main fields of future research are the synthesis of new labelled compounds and the development of mathematical models of the biological processes to be investigated. (orig.)

  5. [Fundamentals of positron emission tomography].

    Science.gov (United States)

    Ostertag, H

    1989-07-01

    Positron emission tomography is a modern radionuclide method of measuring physiological quantities or metabolic parameters in vivo. The method is based on: (1) radioactive labelling with positron emitters; (2) the coincidence technique for the measurement of the annihilation radiation following positron decay; (3) analysis of the data measured using biological models. The basic aspects and problems of the method are discussed. The main fields of future research are the synthesis of new labelled compounds and the development of mathematical models of the biological processes to be investigated. PMID:2667029

  6. Secondary emission monitor (SEM) grids.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    A great variety of Secondary Emission Monitors (SEM) are used all over the PS Complex. At other accelerators they are also called wire-grids, harps, etc. They are used to measure beam density profiles (from which beam size and emittance can be derived) in single-pass locations (not on circulating beams). Top left: two individual wire-planes. Top right: a combination of a horizontal and a vertical wire plane. Bottom left: a ribbon grid in its frame, with connecting wires. Bottom right: a SEM-grid with its insertion/retraction mechanism.

  7. Equilibrium emission of nuclear fragments

    International Nuclear Information System (INIS)

    In the present paper data are presented which demonstrate that for IMF production the use of intermediate energy heavy-ion-induced reactions at energies of 15-30 MeV/nucleon is extremely tenuous due to the possibility of contributions from deep inelastic collisions, fission and from preequilibrium mechanisms. Furthermore it is argued that the apparent temperatures extracted from the slopes of the fragment energy spectra correlate with the reaction variables in a manner which is more consistent with pre-equilibrium emission in the spirit of the exciton model, instead of a spatially localized thermal excitation or a 'hot spot'. (orig./BBOE)

  8. A Grid-Based Mobile Sources Emissions Inventory Model

    OpenAIRE

    Zheng, Yi; Niemeier, Debbie; Kear, Tom

    2001-01-01

    In general, the limitations of the current California vehicle emissions inventory models can be summarized as: - There is no direct connection between the regional emissions inventory model and the gridded emissions model. Separate model runs must be processed to develop regional emissions inventories and gridded emissions. - The emission estimates from the regional emissions inventory model and the gridded emissions model are not in agreement. - The regional emissi...

  9. Emissions of Greenhouse gases in the Netherlands

    Energy Technology Data Exchange (ETDEWEB)

    Evers, C.W.A. [Ministry of Housing, The Hague (Netherlands). Inspectorate for Environmental Protection; Berdowski, J.J.M.; Pulles, T.P.J. [TNO Inst. for Environmental Sciences, Delft (Netherlands)

    1995-12-31

    The Dutch emission inventory system enables the registration, analysis and localization of emission data of both industrial and non-industrial sources in the Netherlands. The results can be used to test the effectiveness of governmental environmental policy. These activities are part of the policy evaluation tasks of the Inspectorate General for Environmental Protection (IGEP) and of the Ministry of Transport, Public Works and Water Management. The emission inventory takes place in cycles of one year. Recently, the most relevant results of the Dutch emission inventory for 1992 have been published. In that cycle the emissions in 1992 to air and water from about 800 major companies have been registered. These 800 companies are the most important contributors to the total industrial emissions in the Netherlands. The emissions of these companies are registered within the individual inventory system. The emissions from the smaller enterprises and from diffuse non-industrial sources are stored in the collective emission inventory system. The data collected in the 1992 inventory have been established for the first time in close cooperation between the IGEP, TNO, the Central Bureau of Statistics and the National Institute of Public Health and Environmental Protection. This implies that the data presented here have to be considered as the official data for the emissions in the Netherlands for the year 1992. (author)

  10. Dioxin air emission inventory 1990-2004

    Energy Technology Data Exchange (ETDEWEB)

    Capral Henriksen, T.; Illerup, J.B.; Nielsen, Ole-Kenneth [DMU, Dept. of Policy Analysis (Denmark)

    2006-12-15

    The present Danish dioxin air emission inventory shows that the emission has been reduced from 68.6 g I-TEQ in 1990 to 22.0 g I-TEQ in 2004, or about 68% over this period. Most of the significant reductions have been achieved in the industrial sector, where emissions have been reduced from 14.67 g I-TEQ in 1990 to 0.17 g I-TEQ in 2004; a reduction of almost 99%. Lower emissions from steel and aluminium reclamation industries form the major part of the reduction within industry. Emissions from waste incineration reduced from 32.5 g I-TEQ in 1990 to 2.1 g ITEQ in 2004; which is approx. 94%. This is due to installation of dioxin abatement equipment in incineration plants. The most important source of emission in 2004 is residential wood combustion, at 8.5 g I-TEQ, or around 40% of the total emission. In 2004, accidental fires, which are estimated to emit 6.1 g I-TEQ/year, are the second most important source, contributing with around 28% of the total emission. The present dioxin emission inventory for Denmark shows how emissions in 2004 come from sources other than waste incineration plants and industry, which were the largest sources in 1990. (au)

  11. Imported emissions. The world trade stowaway

    International Nuclear Information System (INIS)

    This study first gives an overview of existing tools and methodological challenges to account emissions included in consumed products fabricated elsewhere. It notably discusses the passage from a methodology based on a production principle to a methodology based on a consumption principle, outlines the different methodologies associated with the different analysis levels, and the importance of uncertainty sources. The second part proposes a view on emission flows included in exports and imports. It addresses the following issues: the international level, increasing importance of emissions transferred via world trade, emissions related to consumption per capita and per social class, carbon and energy intensity of products at the origin of emissions, composition of imported and exported products and intensity of their emissions, impact of a methodological change on greenhouse gas emissions by France, extent of emissions imported in France, and Germany as the first trade partner and emission importer of France. The third part discusses the political implications of an accounting of emissions related to consumption and to world trade

  12. Emissions scenarios: a final response

    Energy Technology Data Exchange (ETDEWEB)

    Gruebler, A.; Nakicenovic, N.; Alcamo, J. (and others)

    2004-01-01

    This note is a final response to the debate raised by Mr. Castles and Mr. Henderson (for brevity, we refer here to the two authors simply as C and H) in this Journal (vol 14, no 2 and 3, and no 4) on the issue of economic growth in developing countries in some of the emissions scenarios published in the IPCC Special Report on Emissions Scenarios (SRES) (Nakicenovic et al., 2000). We first outline areas of agreement and then the remaining areas of disagreement. Two important areas of agreement have emerged from the debate according to our view. First, both parties agree that scenarios assuming a conditional convergence in income levels, i.e., a higher growth in per capita income in poorer countries when compared to countries with higher levels of affluence, are both 'plausible and well attested in economic history' (C and H, p. 424). Thus, the fundamental, structural characteristic of some of the SRES scenarios contested by C and H are not challenged per se, but rather how fast such trends could unfold in the future. (author)

  13. Emissions scenario: a final response

    Energy Technology Data Exchange (ETDEWEB)

    Gruebler, A.; Nakicenovic, N.; Alcamo, J. (and others)

    2004-01-01

    This note is a final response to the debate raised by Mr Castles and Mr Henderson (for brevity, we refer here to the two authors simply as C and H) in this Journal (vol. 14, no. 2 and 3, and no. 4) on the issue of economic growth in developing countries in some of the emissions scenarios published in the IPCC Special Report on Emissions Scenarios (SRES) (Nakicenovic et al., 2000). We first outline areas of agreement and then the remaining areas of disagreement. Two important areas of agreement have emerged from the debate according to our view. First, both parties agree that scenarios assuming a conditional convergence in income levels, i.e., a higher growth in per capita income in poorer countries when compared to countries with higher levels of affluence, are both ''plausible and well attested in economic history'' (C and H, p. 424). Thus, the fundamental, structural characteristic of some of the SRES scenarios contested by C and H are not challenged per se, but rather how fast such trends could unfold in the future. (author)

  14. Reducing emissions from uranium dissolving

    International Nuclear Information System (INIS)

    This study was designed to assess the feasibility of decreasing NOx emissions from the current uranium alloy scrap tray dissolving facility. In the current process, uranium scrap is dissolved in boiling nitric acid in shallow stainless-steel trays. As scrap dissolves, more metal and more nitric acid are added to the tray by operating personnel. Safe geometry is assured by keeping liquid level at or below 5 cm, the depth of a safe infinite slab. The accountability batch control system provides additional protection against criticality. Both uranium and uranium alloys are dissolved. Nitric acid is recovered from the vapors for reuse. Metal nitrates are sent to uranium recovery. Brown NOx fumes evolved during dissolving have occasionally resulted in a visible plume from the trays. The fuming is most noticeable during startup and after addition of fresh acid to a tray. Present environmental regulations are expected to require control of brown NOx emissions. A detailed review of the literature, indicated the feasibility of slightly altering process chemistry to favor the production of NO2 which can be scrubbed and recycled as nitric acid. Methods for controlling the process to manage offgas product distribution and to minimize chemical reaction hazards were also considered

  15. Flare emission from Sagittarius A*

    CERN Document Server

    Eckart, A; Vogel, S N; Teuben, P; Morris, M R; Baganoff, F; Dexter, J; Schoedel, R; Witzel, G; Valencia-S., M; Karas, V; Kunneriath, D; Bremer, M; Straubmeier, C; Moser, L; Sabha, N; Buchholz, R; Zamaninasab, M; Muzic, K; Moultaka, J; Zensus, J A

    2012-01-01

    Based on Bremer et al. (2011) and Eckart et al. (2012) we report on simultaneous observations and modeling of the millimeter, near-infrared, and X-ray flare emission of the source Sagittarius A* (SgrA*) associated with the super-massive black hole at the Galactic Center. We study physical processes giving rise to the variable emission of SgrA* from the radio to the X-ray domain. To explain the statistics of the observed variability of the (sub-)mm spectrum of SgrA*, we use a sample of simultaneous NIR/X-ray flare peaks and model the flares using a synchrotron and SSC mechanism. The observations reveal flaring activity in all wavelength bands that can be modeled as the signal from adiabatically expanding synchrotron self-Compton (SSC) components. The model parameters suggest that either the adiabatically expanding source components have a bulk motion larger than v_exp or the expanding material contributes to a corona or disk, confined to the immediate surroundings of SgrA*. For the bulk of the synchrotron and ...

  16. Single-photon emission tomography.

    Science.gov (United States)

    Goffin, Karolien; van Laere, Koen

    2016-01-01

    Single-photon emission computed tomography (SPECT) is a functional nuclear imaging technique that allows visualization and quantification of different in vivo physiologic and pathologic features of brain neurobiology. It has been used for many years in diagnosis of several neurologic and psychiatric disorders. In this chapter, we discuss the current state-of-the-art of SPECT imaging of brain perfusion and dopamine transporter (DAT) imaging. Brain perfusion SPECT imaging plays an important role in the localization of the seizure onset zone in patients with refractory epilepsy. In cerebrovascular disease, it can be useful in determining the cerebrovascular reserve. After traumatic brain injury, SPECT has shown perfusion abnormalities despite normal morphology. In the context of organ donation, the diagnosis of brain death can be made with high accuracy. In neurodegeneration, while amyloid or (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) are the nuclear diagnostic tools of preference for early and differential diagnosis of dementia, perfusion SPECT imaging can be useful, albeit with slightly lower accuracy. SPECT imaging of the dopamine transporter system is widely available in Europe and Asia, but since recently also in the USA, and has been accepted as an important diagnostic tool in the early and differential diagnosis of parkinsonism in patients with unclear clinical features. The combination of perfusion SPECT (or FDG-PET) and DAT imaging provides differential diagnosis between idiopathic Parkinson's disease, Parkinson-plus syndromes, dementia with Lewy bodies, and essential tremor. PMID:27432669

  17. Greenhouse Gas Emissions From Cattle

    Directory of Open Access Journals (Sweden)

    Podkówka Zbigniew

    2015-03-01

    Full Text Available Cattle produce greenhouse gases (GHG which lead to changes in the chemical composition of the atmosphere. These gases which cause greenhouse effect include: methane (CH4, nitrous oxide (N2O, nitrogen oxides (NOx, sulphur dioxide (SO2, ammonia (NH3, dust particles and non-methane volatile organic compounds, commonly described as other than methane hydrocarbons. Fermentation processes taking place in the digestive tract produce ‘digestive gases’, distinguished from gases which are emitted during the decomposition of manure. Among these digestive gases methane and non-methane volatile organic compounds are of particular relevance importance. The amount of gases produced by cows can be reduced by choosing to rear animals with an improved genetically based performance. A dairy cow with higher production efficiency, producing milk with higher protein content and at the same time reduced fat content emits less GHG into the environment. Increasing the ratio of feed mixtures in a feed ration also reduces GHG emissions, especially of methane. By selection of dairy cows with higher production efficiency and appropriate nutrition, the farm's expected milk production target can be achieved while at the same time, the size of the herd is reduced, leading to a reduction of GHG emissions.

  18. 47 CFR 87.137 - Types of emission.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Types of emission. 87.137 Section 87.137... Technical Requirements § 87.137 Types of emission. (a) The assignable emissions, corresponding emission designators and authorized bandwidths are as follows: Class of emission Emission designator...

  19. An Emission Saved is an Emission Earned: An Empirical Study of Emission Banking for Light-Duty Vehicle Manufacturers

    OpenAIRE

    Rubin, Jonathan D.; Kling, Catherine

    1993-01-01

    This paper presents results of an empirical study of emission banking for light-duty vehicle manufacturers. An intertemporal model of manufacturers' choices is combined with econometrically estimated abatement cost functions to simulate the cost savings and emission effects of an averaging, trading, and banking marketable permit system relative to command-and-control regulations. While the cost savings of such a system are estimated to be modest, the intertemporal emission effects may be siza...

  20. Allocation of CO2 emission allowances. Distribution of emission allowances in a European emissions trading scheme

    Energy Technology Data Exchange (ETDEWEB)

    Harmsen, H.; Van der Kolk, J. [KPMG Sustainability, Amstelveen (Netherlands); Kerssemeeckers, M.; De Beer, J. [Ecofys, Utrecht (Netherlands)

    2002-10-01

    The European Commission has submitted a draft directive on Emissions Trading on 23 October 2001. In this system, each Member State has to submit an allocation plan that describes the allowances that will be distributed, and how these will be distributed among the operators of each participating installation. In this study the possible allocation options and their consequences are investigated; the potential bottlenecks are assessed, which would occur if the Netherlands developed a national allocation plan; the criteria for national allocation plans are assessed (Annex III draft directive); and some possibilities for solutions are presented.