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1612. Air ejector with a diffuser that includes boundary layer suction

Creator:
Dvořák, Václav
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
air ejector, diffuser, and boundary layer suction
Language:
English
Description:
The article deals with axial-symmetric subsonic air-to air ejector with a diffuser adapted for boundary layer suction. The diffuser, which is placed after the mixing chamber of the ejector, has a high divergence angle and is therefore inefficient. To increase efficiency, the diffuser is equipped with a slot enabling boundary layer suction. The effect of boundary layer suction on the airflow in the ejector was measured, as were the static pressure distribution on the mixing chamber wall and ejector characteristics. Both diffuser and ejector efficiency were calculated. Although the efficiency of the diffuser was increased, the efficiency of the ejector itself remained low. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1613. Air lime mortars with incorporation of sepiolite and synthetic zeolite pellets

Creator:
Andrejkovičová, Slávka, Ferraz, Eduardo, Velosa, Ana L., Silva, António S., and Rocha, Fernando
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, vápno, malty, syntetické zeolity, lime, mortar, synthetic zeolites, sepiolite, synthetic zeolite pellets, 7, and 551
Language:
English
Description:
The requirements of conservators who take care of historical monuments are that the materials for rehabilitation of old renders should have a composition as similar to the historical materials as possible and should provide improvement in durability. Fine and coarse sepiolite and synthetic zeolite pellets were chosen as additives in the development of lime mortars for conservation work, due to their unique adsorption properties providing water to the mortar system and acting as water reservoirs in conditions of low humidity. Flexural and compressive strength and the dynamic modulus of elasticity were studied at 28, 90 and 180 days of curing. Addition of both fine and coarse sepiolite and zeolite pellets caused improvement of mechanical strength of mortars, clearly evident at later ages of curing. Elasticity modulus ranged from 2.3 GPa to 3.6 GPa relating to a high deformation capability of mortars and confirming their suitability for use in conservation work., Slávka Andrejkovičová, Eduardo Ferraz, Ana L. Velosa, António S. Silva and Fernando Rocha., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1615. Air temperature changes in a burrow of Chinese pangolin, Manis pentadactyla, in winter

Creator:
Bao, Fangyin, Wu, Shibao, Su, Chao, Yang, Li, Zhang, Fuhua, and Ma, Guangzhi
Type:
article, model:article, and TEXT
Subject:
subterranean mammal, adaptation, wintering, micro-environment, and Luofushan Natural Reserve
Language:
English
Description:
We determined burrow temperature variation for the Chinese pangolin in winter over a study period from 1 December 2009 to 28 February 2010, at Luofushan Nature Reserve, China. Our results show that the air temperature inside the burrow was stable with only a slight fluctuation, the diurnal variation amplitude was merely 0.0-0.5 °C (SD = 0.08 ± 0.09 °C, n = 90), and winter temperature fluctuated between 17.8-21.0 °C. On the contrary, air temperature outside the burrow fluctuated dramatically, the diurnal variation amplitude ranging from 0.7-20.0 °C (SD = 4.99 ± 3.47 °C, n = 90); the seasonal temperature fluctuated between 4.6-38.3 °C. In winter, the average temperature inside the burrow was 18.96 °C (SD = 0.91, n = 90), and significantly higher than the average temperature outside the burrow (p < 0.01), which was 15.16 °C (SD = 3.85, n = 90). No significant relationship was found between the temperatures inside and outside the burrow, and the temperature changes outside the burrow had almost no significant influence on thermal conditions inside the burrow. It was therefore proposed that the most optimum ambient temperature for Chinese pangolins in winter was in the range of 18-21 °C.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1617. Air Traffic Control Communication

Creator:
Šmídl, Luboš
Publisher:
University of West Bohemia, Department of Cybernetics
Type:
audio and corpus
Subject:
speech corpus and acoustic model
Language:
English
Description:
Corpus contains recordings of communication between air traffic controllers and pilots. The speech is manually transcribed and labeled with the information about the speaker (pilot/controller, not the full identity of the person). The corpus is currently small (20 hours) but we plan to search for additional data next year. The audio data format is: 8kHz, 16bit PCM, mono. and Technology Agency of the Czech Republic, project No. TA01030476.
Rights:
Creative Commons - Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), http://creativecommons.org/licenses/by-nc-sa/4.0/, and PUB

1618. Air-pressure, vocal fold vibration and acoustic characteristics of phonation during vocal exercising. Part 1. Measurement in vivo

Creator:
Radolf, Vojtěch, Laukkanen, Anne-Maria, Horáček, Jaromír, and Liu, Dong
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
biomechanics of voice, subglottal, oral and transglottal pressure, electroglottography, and phonation into tubes
Language:
English
Description:
The study investigates differences between three most widely used methods in voice training and therapy: Phonation into a resonance tube with the outer end in the air or submerged 2-10 cm in water (‘water resistance therapy‘ with bubbling effect), and phonation into a very thin straw. One female speech trainer served as subejct. Acoustic and electroglottographic (EGG) signals, and both mean and dynamic air pressures in the mouth cavity were registered for repetitions of [pu:pu], and for phonation into the tubes, while the outer end was randomly shuttered in order to get an estimate of subglottic pressure. Soft and normal phonations were recorded. Phonation threshold decreased with tube in air, suggesting that increased input reactance assists small amplitude oscillation of the vocal folds. Oral pressure (Poral) increased with increasing impedance offered by the tube and straw, most when the tube was 10 cm in water. In most cases subglottic pressure (Psub) increased relatively more than Poral, so that tranglottic pressure (Ptrans) was higher in the exercises compared to vowel. Contact quotient (CQ) from EGG increased, which may be due to increased Ptrans. In tube 10 cm in water Ptrans decreased and CQ increased suggesting increased adduction as compensation. Exercises that increase oral eir-pressure offer a possibility to train flottal and respiratory adjustments under the influence of increased flow resistance which may prevent excessively strong vocal fold collisions. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1619. Air-pressure, vocal folds vibration and acoustic characteristics of phonation during vocal exercising. Part 2. Measurement on a physical model

Creator:
Horáček, Jaromír, Radolf, Vojtěch, Bula, Vítězslav, and Laukkanen, Anne-Maria
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
biomechanics of voice, subglottal, oral and transglottal pressure, and flow resistance
Language:
English
Description:
The contribution aims to provide material that can be used in development of more realistic physical as well as theoretical models of voice production. The experimental set-up methodology and the results of measurement of airflow rate, subglottal, oral and generated acoustic air pressures are presented together with the simultaneously measured flow-induced vibrations of a vocal folds replica, made of soft silicon rubber, and recorded by a high speed camera. The data were measured during ‘soft‘ phonation onset, given by the phonation threshold airflow rate, and during ‘normal‘ phonation for the airflow rate of about three times higher. A model of the human vocal tract in the position for production of vowel [u:] was used, and the flow resistance was raised by phonating into a glass resonance tube either in the air or having the other end of the tube submerged under water, and by phonating into a narrow straws. The results for the pressures presented in time and frequency domain are comparable with the physiological ranges and limits measured in humans for ordinary phonation and for production of vocal exercises used in voice therapy. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1620. Aircraft engine lubricating oil monitoring by process neural network

Creator:
Gang, Ding and Shisheng, Zhong
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Lubricating oil monitoring, process neural network (PNN), Time series prediction, aircraft engine condition monitoring, and orthogonal basis function
Language:
English
Description:
The aircraft engine lubricating oil monitoring is essential in terms of the flight safety and also for reduction of the maintenance cost. The concentration of metal elements in the lubricating oil includes a large amount of information about the health condition of the aircraft engine. By monitoring the lubricating oil, maintenance engineers can judge the performance deterioration of the aircraft engine and can find the latent mechanical faults in the aircraft engine in advance. But it is difficult for traditional methods to predict the tendency of the mental elements concentration in the lubricating oil. In this paper, a time series prediction method based on process neural network (PNN) is proposed to solve this problem. The inputs and the connection weights of the PNN are time-varied functions. A corresponding learning algorithm is developed. To simplify the learning algorithm, a set of appropriate orthogonal basis functions are introduced to expand the input functions and the connection weight functions of the PNN. The effectiveness of the proposed method is proved by the Mackey-Glass time series prediction. Finally, the proposed method is utilized to predict the Fe concentration in the aircraft engine lubricating oil monitoring, and the test results indicate that the proposed model seems to perform well and appears suitable for using as a predictive maintenance tool.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

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