scholarly journals Sound quality assessment of a medium-range aircraft with enhanced fan-noise shielding design

2021 ◽  
Author(s):  
Gil Felix Greco ◽  
Lothar Bertsch ◽  
Tobias P. Ring ◽  
Sabine C. Langer
Keyword(s):  
Quality Assessment ◽  
Quantitative Description ◽  
Aircraft Design ◽  
Sound Quality ◽  
Aircraft Noise ◽  
Design Stage ◽  
Short Term ◽  
Fan Noise ◽  
Medium Range ◽  
Noise Shielding

AbstractThe investigation of technologies that can improve the sustainability of the air transport system requires not only the development of alternative fuel concepts and novel vehicle technologies but also the definition of appropriate assessment strategies. Regarding noise, the assessment should reflect the situation of communities living near airports, i.e., not only addressing sound levels but also accounting for the annoyance caused by aircraft noise. For this purpose, conventional A-weighted sound pressure level metrics provide initial but limited information as the level- and frequency-dependency of the human hearing is accounted for in a simplified manner. Ideally, subjective evaluations are required to adequately quantify the perceived short-term annoyance associated with aircraft noise. However, listening tests are time-consuming and not suitable to be applied during the conceptual aircraft design stage, where a large solution space needs to be explored. Aiming at bridging this gap, this work presents a methodology for the sound quality assessment of computational aircraft noise predictions, which is hereby conducted in terms of objective psychoacoustic metrics. The proposed methodology is applied to a novel medium-range vehicle with fan noise shielding architecture during take-off and landing procedures. The relevance of individual sound sources, i.e., airframe and engine noise contributions, and their dependencies on the aircraft architecture and flight procedures are assessed in terms of loudness, sharpness, and tonality. Moreover, the methodology is steered towards community noise assessment, where the impacts on short-term annoyance brought by the novel aircraft design are analysed. The assessment is based on the modified psychoacoustic annoyance, a metric that provides a quantitative description of human annoyance as a combination of different hearing sensations. The present work is understood as an essential step towards low-annoyance aircraft design.

Sound Quality Assessment of Powered Seat Adjusters

1995 ◽  
Author(s):  
Gabriella Cerrato ◽  
Alun Crewe ◽  
John Terech
Keyword(s):  
Quality Assessment ◽  
Sound Quality

scholarly journals Options for solving the problem of parts of the Shelter object located outside the New Safe Confinement

2020 ◽  
Vol 19 (4) ◽  
pp. 57-65
Author(s):  
O. V. Balan ◽  
◽  
S. Gh. Brylka ◽  
V. V. Derengovskyi ◽  
V. V. Yehorov ◽  
...  
Keyword(s):  
Cost Effective ◽  
Radiation Condition ◽  
Design Stage ◽  
Final Decision ◽  
Building Structures ◽  
Short Term ◽  
Design Studies ◽  
Financial Costs ◽  
Work Area ◽  
Goals And Objectives

The parts of the Shelter object structures remained outside the New Safe Confinement (protruding parts) are considered in the article. The analysis of the building structures condition of the turbine hall and the deaerator stack protruding parts on the east and west sides is carried out and the necessity of works on strengthening and/or dismantling of bearing structures is confirmed. Possible variants of reconstruction of the Shelter object protruding parts are stated and the technological sequence of works is provided. The analysis of the possibilities of performing works in the conditions of functioning of the New Safe Confinement — Shelter object system proved that such activity is rather difficult task, which can cause significant physical and financial costs. As there is no guarantee of trouble-free operation of the building structures of the protruding parts during the entire service life of the New Safe Confinement, it is necessary to make every effort to solve this problem in the short term. The results of the analysis allow to choose the most advantageous solution to the goals and objectives for the safest and most cost/effective dismantling and/or strengthening of structures of protruding parts, taking into account a number of different criteria. These criteria may be different in nature, which allowed to build a generalized efficiency indicator for individual criteria with certain weights that determine the importance of each of the criteria for decision making. Based on the results of the analysis, these options can be considered equivalent. The final decision on the choice of the optimal variant for the Shelter object protruding parts reconstruction can be made after detailing the technological decisions at the design stage of protruding parts reconstruction and before the design studies of the radiation condition in the work area. The obtained information can be used as input data during the design of the reconstruction of the deaerator stack and the turbine hall parts of the Shelter object, which protrude beyond the New Safe Confinement.

Combined effects of short-term noise exposure and hygrothermal conditions on indoor environmental perceptions

2017 ◽  
Vol 27 (8) ◽  
pp. 1119-1133 ◽  
Author(s):  
Wonyoung Yang ◽  
Hyeun Jun Moon ◽  
Myung-Jun Kim
Keyword(s):  
Gender Differences ◽  
Noise Exposure ◽  
Thermal Conditions ◽  
Combined Effects ◽  
Environmental Perceptions ◽  
Noise Levels ◽  
Short Term ◽  
Fan Noise ◽  
Subjective Assessments ◽  
Different Types

Realistic thermal conditions with various humidity levels have been considered to examine the combined effects of noise and thermal conditions on indoor environmental perceptions. Subjective assessments of temperature, humidity and psychoacoustics were conducted with 26 subjects under combined environments of seven thermal conditions (18℃: RH 30, 60%, 24℃: RH 27, 43, 65%, 30℃: RH 30, 60%), two noise types (fan and babble noises) and five noise levels (45, 50, 55, 60 and 65 dBA). Three-minute moderate noise exposure did not affect temperature or humidity sensations. However, the temperature and humidity levels affected loudness, annoyance and acoustic preferences when noise was presented as babble. Fan noise perceptions were found to be independent of thermal conditions. Gender differences were clearly found in terms of thermal and psychoacoustic perceptions. Men were more sensitive to hot sensations than women, and women were more sensitive to arid sensations than men. Women were more sensitive to noise levels than men. Gender differences were also found in terms of different types of noise. Men were found to be significantly less sensitive to fan noise than women. Even though psychoacoustic parameters were affected by indoor thermal conditions, thermal parameters were not affected by short-term moderate noise. The combined effect of various types of noise and temperature is still unclear, and this will be considered in a future larger cohort study.

scholarly journals A Quantitative Description of Short-Term Plasticity at Excitatory Synapses in Layer 2/3 of Rat Primary Visual Cortex

1997 ◽  
Vol 17 (20) ◽  
pp. 7926-7940 ◽  
Author(s):  
Juan A. Varela ◽  
Kamal Sen ◽  
Jay Gibson ◽  
Joshua Fost ◽  
L. F. Abbott ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Quantitative Description ◽  
Excitatory Synapses ◽  
Short Term ◽  
Short Term Plasticity ◽  
Layer 2

scholarly journals Validation data for aircraft noise shielding prediction

2019 ◽  
Vol 10 (1) ◽  
pp. 179-196
Author(s):  
Karl-Stéphane Rossignol ◽  
Jan Werner Delfs ◽  
Michael Mößner ◽  
Markus Lummer ◽  
Jianping Yin
Keyword(s):  
Aircraft Noise ◽  
Validation Data ◽  
Noise Shielding

scholarly journals Impact Assessment of Habitat and Hydromorphological Alterations in Two Heavily Modified Lakes

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 622
Author(s):  
Dionissis Latinopoulos ◽  
Chrysoula Ntislidou ◽  
Ifigenia Kagalou
Keyword(s):  
Quality Assessment ◽  
Impact Assessment ◽  
Water Framework Directive ◽  
Habitat Quality ◽  
Natural Environment ◽  
Quantitative Description ◽  
Assessment Method ◽  
Habitat Modification ◽  
Lake Morphology ◽  
Habitat Quality Assessment

A description of hydromorphological pressures is required by the Water Framework Directive, however, there is not a commonly accepted assessment method. This study aims to explore a description tool application, not used before in Greece, for the quantification of the human impact extent on natural environment. Thus, in lakes Kastoria and Pamvotis, the Lake Habitat Survey was applied in the field and remotely to map the pressures, to examine confidence, suitability and ease of applicability through plot quantitative description, to calculate the “Lake Habitat Quality Assessment”, “Lake Habitat Modification Score” and “Alteration of Lake Morphology Score” indices.

scholarly journals Evaluation of Short-Term Aging Protocol for Asphalt Mixtures

2019 ◽  
Vol 9 (14) ◽  
pp. 2783 ◽  
Author(s):  
Sirin ◽  
Paul ◽  
Kassem ◽  
Ohiduzzaman
Keyword(s):  
Mechanical Properties ◽  
Asphalt Pavement ◽  
Road Construction ◽  
Asphalt Mixtures ◽  
Pavement Performance ◽  
Design Stage ◽  
Construction Site ◽  
Short Term ◽  
Compaction Processes

Asphalt mixtures are subjected to short-term aging during the production, placement, and compaction processes. Proper evaluation of asphalt pavement performance relies on the accurate characterization of asphalt mixtures during the design stage. In this study, three different loose asphalt mixtures often used in Qatar were evaluated to develop a laboratory short-term aging procedure. Sample mixtures 1 and 3 were collected from a construction site, while mixture 2 was obtained from an asphalt plant. Virgin aggregates and binders were also collected to reproduce the mixtures in the laboratory. Laboratory-produced mixtures were conditioned at 135 °C using various time durations. The mechanical properties of laboratory-produced mixtures were compared to those of mixtures produced on site. The results of the mechanical and binder testing demonstrated that the proper short-term aging protocol for asphalt mixtures often used in road construction in the State of Qatar would involve heating asphalt mixtures for 4 h at 135 °C before laboratory compaction.

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