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- Effects of Noise and Reverberation on Human Perception and Performance (12)
- Room acoustics (12)
- Noise (9)
- Computer Modeling and Prediction of Room Acoustics (7)
- Linking Room Acoustic Subjective Perception and Objective Metrics (7)
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- Human performance (6)
- Human perception (5)
- Auralization (4)
- Building mechanical systems (4)
- Scattering and Diffusion in Room Acoustics (4)
- Classroom acoustics (3)
- Coupled Volume Room Acoustics (3)
- Noise criteria (3)
- Violin Acoustics (3)
- Speech comprehension (2)
- Student achievement (2)
- Violin acoustics (2)
- Acoustic radiation (1)
- Acoustic reflectors (1)
- Auralizations (1)
- Coupled volume (1)
- Coupled volumes (1)
- Diffraction (1)
- Diffuse reflections (1)
- Education (1)
- Fluctuating noise (1)
- Hospital (1)
- Hvac (1)
- Just noticeable difference (1)
- Low frequency noise (1)
Articles 1 - 30 of 35
Full-Text Articles in Mechanical Engineering
Directivity Patterns Of Acoustic Radiation From Bowed Violins, Lily M. Wang, Courtney B. Burroughs
Directivity Patterns Of Acoustic Radiation From Bowed Violins, Lily M. Wang, Courtney B. Burroughs
Lily M Wang
Directivity patterns of acoustic radiation have been measured in the far-field of a violin, excited with an open-frame mechanical bowing machine. Analysis of the directivity patterns confirms that, at frequencies below 600 Hz, the violin radiates omnidirectionally, while above 600 Hz, certain trends are apparent as the patterns become increasingly complex. It is noted that when different strings are excited, the far-field radiation patterns observed at nearly the same frequency are similar, even in higher frequency ranges where modal overlap is high. When the difference in frequency between two directivity patterns exceeds some fraction of a semitone, though, the measured …
Quantifying The Just Noticeable Difference Of Reverberation Time With Band-Limited Noise Centered Around 1000 Hz Using A Transformed Up-Down Adaptive Method, Matthew G. Blevins, Adam T. Buck, Zhao Peng, Lily M. Wang
Quantifying The Just Noticeable Difference Of Reverberation Time With Band-Limited Noise Centered Around 1000 Hz Using A Transformed Up-Down Adaptive Method, Matthew G. Blevins, Adam T. Buck, Zhao Peng, Lily M. Wang
Lily M Wang
This study seeks to quantify the just noticeable difference (JND) of reverberation time (RT) using band-limited noise. ISO 3382-1 lists the JND of reverberation metrics at 5% based on work by Seraphim (1958). However, others have found the JND of RT to be higher from 6% to 39%. Many of these studies utilized band-limited stimuli, e.g. speech, music motifs and bandlimited noise. A previous study by the authors conducted on 30 subjects using white noise demonstrated a JND of RT at 22%. To further verify these results and investigate potential upward frequency masking, the present study was conducted following the …
Rating Low Levels Of Ambient Noise In Performing Arts Facilities, Lily M. Wang, Brent A. Kraay
Rating Low Levels Of Ambient Noise In Performing Arts Facilities, Lily M. Wang, Brent A. Kraay
Lily M Wang
Previous studies have indicated that common indoor noise rating metrics, such as Noise Criteria NC and Room Criteria RC, do not best correlate to human perceptions of annoyance and distraction in typical office environments. Based on investigations conducted at the University of Nebraska using noise levels between 30 – 60 dBA, the author has proposed that an effective indoor noise rating method should begin with a rating of level (either dBA or sones), then an assessment of spectral quality, tones, and fluctuations. How well would such a system work at very low levels of ambient noise, though, as found in …
Effects Of Reverberation And Noise On Speech Comprehension By Native And Non-Native English-Speaking Listeners, Zhao Peng, Lily M. Wang, Siu Kit Lau, Adam M. Steinbach
Effects Of Reverberation And Noise On Speech Comprehension By Native And Non-Native English-Speaking Listeners, Zhao Peng, Lily M. Wang, Siu Kit Lau, Adam M. Steinbach
Lily M Wang
Previous studies have demonstrated the negative impact of adverse signal-to-noise-ratios on non-native English-speaking listeners' performance on speech recognition using recall tasks, as well as implied that comprehension skills were more impaired than recognition skills under reverberation and noise. The authors have themselves previously conducted a pilot study on three native and three non-native Englishspeaking listeners to examine the effects of reverberation and noise using speech comprehension tasks. Those results suggested that speech comprehension performance is worse under longer reverberation times (RT), and that a longer RT is more detrimental to speech comprehension by non-native listeners than native listeners. This paper …
Comparison Of Radiated Power From Structurally Different Violins, Lily M. Wang, Courtney B. Burroughs
Comparison Of Radiated Power From Structurally Different Violins, Lily M. Wang, Courtney B. Burroughs
Lily M Wang
The acoustic power has been determined from intensity measurements on three structurally different violins: a Scherl and Roth student violin, Hutchins' SUS29S, and Hutchins' mezzo violin SUS 100. While each violin was bowed with an open-frame mechanical bowing machine, the intensity measurements were made by scanning each side of the bowing machine with an intensity probe. One-third octave band sound power levels of the acoustic radiation from each of the three instruments as each of the four open strings is bowed show that the structurally different mezzo violin produces greater power at low frequencies when the lowest (G) string is …
Effects Of Background Noise Alternating Between Two Levels At Varying Time Intervals On Human Perception And Performance, Andrew Hathaway, Lily M. Wang
Effects Of Background Noise Alternating Between Two Levels At Varying Time Intervals On Human Perception And Performance, Andrew Hathaway, Lily M. Wang
Lily M Wang
This research experiment aims to better quantify human perception and performance under increased background noise levels of varying intervals. Twenty-seven participants were tested over five 30 minute sessions where they were subjected to RC-29(H) and RC-47(RV) conditions created by broadband noise fluctuating on different time intervals. These intervals varied from two minutes to ten minutes, simulating the conditions of a noisy HVAC system turning on and off. The performance results of an arithmetic test dealing with short-term memory and a subjective questionnaire will be presented and compared to a similar test using broadband noise bursts and correlated to noise metrics …
Scattered Responses From Suspended Reflector Panels With Rounded Edges, Jonathan Rathsam, Lily M. Wang
Scattered Responses From Suspended Reflector Panels With Rounded Edges, Jonathan Rathsam, Lily M. Wang
Lily M Wang
Sound reflections from most finite surfaces, such as overhead reflector panels, include a component known as edge diffraction. Edge diffraction is the scattered energy required to maintain a continuous sound field despite the discontinuity in acoustical impedance presented by the scatterer. Edge diffraction can interfere with primary scattered energy to produce comb filtering at receiver locations. Several decades ago, the effect of changing the edge profile of loudspeaker boxes was investigated with the goal of producing a smoother frequency response. By rounding the edges of loudspeaker boxes, the edge diffraction could be decreased noticeably [H. F. Olson, J. Aud. Eng. …
Effects Of Noise On Productivity: Does Performance Decrease Over Time?, Jessica Errett, Erica Eileen Bowden, Marc Choiniere, Lily M. Wang
Effects Of Noise On Productivity: Does Performance Decrease Over Time?, Jessica Errett, Erica Eileen Bowden, Marc Choiniere, Lily M. Wang
Lily M Wang
Most people at one time or another have found themselves irritated or distracted by the background noise in a building. The irritation might have resulted in minor aggravation or may have been dramatic enough to hinder their work. This leads us to ask whether occupants are increasingly aggravated by noise the longer they are exposed to it, or if they naturally habituate to their acoustic environment. In an effort to answer this question, a study was completed in the “Indoor Environment Lab” at the University of Nebraska. This lab resembles a typical office and was specially constructed to be acoustically …
Ab-10-C037: Effects Of Noise From Building Mechanical Systems On Elementary School Student Achievement, Lauren M Ronsse, Lily M. Wang
Ab-10-C037: Effects Of Noise From Building Mechanical Systems On Elementary School Student Achievement, Lauren M Ronsse, Lily M. Wang
Lily M Wang
This project seeks to determine what relationship, if any, exists betweenbackground noise levels in elementary classrooms due to the building mechanicalsystems and student performance on achievement tests. Previous research inclassroom acoustics has clearly identified that lower background noise levelsresult in higher speech intelligibility which is crucial for the learning process;however, there is a lack of data correlating lower noise levels to improved studentachievement scores. For this study, background noise level measurements were madein 14 elementary schools in a public school system in Council Bluffs, Iowa, USA.The measurements were made in unoccupied classrooms with the central buildingmechanical systems activated. Second and …
Effects Of Changing The Amount Of Absorption In A Computer Model Of Queen’S Hall, Copenhagen, Denmark, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel
Effects Of Changing The Amount Of Absorption In A Computer Model Of Queen’S Hall, Copenhagen, Denmark, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel
Lily M Wang
Room acoustics modelling and auralizations are very useful tools in the design of acoustically sensitive spaces. One area of improvement for auralizations is the method of modelling the source directivity. A new method to incorporate source directivity is multi-channel auralizations. This study first evaluates the objective effects of using four and thirteen channel impulse responses in an ODEON model of Queen’s Hall, where the actual variable absorption is changed within the model. Analyses of the results reveal great differences in the objective parameters of reverberation time and sound pressure level across each channel’s impulse response. Subjective studies were then conducted …
Binaural Room Impulse Response Database Acquired From A Variable Acoustics Classroom, Zhao Peng, Siu Kit Lau, Lily M. Wang, Sean Browne, Kenneth P. Roy
Binaural Room Impulse Response Database Acquired From A Variable Acoustics Classroom, Zhao Peng, Siu Kit Lau, Lily M. Wang, Sean Browne, Kenneth P. Roy
Lily M Wang
Room measurements were conducted in a variable acoustics classroom mockup space (epod) at Armstrong World Industries in Lancaster, Pennsylvania, USA. Binaural room impulse responses were measured in the epod using a head and torso simulator. Five reverberation time (RT) scenarios were achieved with various combinations of absorptive wall panels and acoustical ceiling tile. These provided a range of mid-frequency RTs from 0.4 to 1.1 seconds. Three of the five RT scenarios were achieved using two different material configurations to also consider material location effects. For each of the eight material configurations, two student-teacher orientations were tested. One orientation had all …
Or-05-6-4: Relating Human Productivity And Annoyance To Indoor Noise Criteria Systems: A Low Frequency Analysis, Erica Eileen Bowden, Lily M. Wang
Or-05-6-4: Relating Human Productivity And Annoyance To Indoor Noise Criteria Systems: A Low Frequency Analysis, Erica Eileen Bowden, Lily M. Wang
Lily M Wang
A number of indoor noise criteria systems are used to quantify the background noise in a built environment, including Noise Criteria (NC), Balanced Noise Criteria (NCB), Room Criteria (RC), Room Criteria Mark II (RC Mark II), A-weighted Equivalent Sound Pressure Level (LAeq), and others. An on-going debate exists in the acoustical community over which criterion is the most appropriate to use in the variety of ambient noise situations encountered. In an effort to quantitatively support the use of individual criterion, this project subjectively correlates these various criteria with human task performance and perception. Eleven subjects participated in a pilot study …
Investigations Of Multi-Channel Auralization Technique For Various Orchestra Arrangements, With Phase-Shifted String Sections, Michelle C Vigeant, Lily M. Wang
Investigations Of Multi-Channel Auralization Technique For Various Orchestra Arrangements, With Phase-Shifted String Sections, Michelle C Vigeant, Lily M. Wang
Lily M Wang
An orchestra can be simulated in room acoustics computer modelling using a variety of methods, ranging from a single omni-directional source to individual sources of all instruments. This study utilizes the method of individual sources for each instrument, but with reduced source representation for the string sections. The anechoic recordings used in this investigation are five-channel recordings, which capture the source directivity of the individual instruments. For each string section, the individual anechoic recordings were phase shifted several times, up to 23 ms, and combined to create a single recording for use in the simulations. An orchestra was simulated in …
Scattered Responses From Suspended Reflector Panels With Rounded Edges, Jonathan Rathsam, Lily M. Wang
Scattered Responses From Suspended Reflector Panels With Rounded Edges, Jonathan Rathsam, Lily M. Wang
Lily M Wang
Sound reflections from most finite surfaces, such as overhead reflector panels, include a component known as edge diffraction. Edge diffraction is the scattered energy required to maintain a continuous sound field despite the discontinuity in acoustical impedance presented by the scatterer. Edge diffraction can interfere with primary scattered energy to produce comb filtering at receiver locations. Several decades ago, the effect of changing the edge profile of loudspeaker boxes was investigated with the goal of producing a smoother frequency response. By rounding the edges of loudspeaker boxes, the edge diffraction could be decreased noticeably [H. F. Olson, J. Aud. Eng. …
The Effects Of Simple Coupled Volume Geometry On The Objective And Subjective Results From Nonexponential Decay, David T. Bradley, Lily M. Wang
The Effects Of Simple Coupled Volume Geometry On The Objective And Subjective Results From Nonexponential Decay, David T. Bradley, Lily M. Wang
Lily M Wang
This project focuses on the individual and interactive acoustic effects of three architectural parameters on the double slope profile from a simple coupled volume system created in the computer modeling program ODEON. The three variables studied are the volume ratio between the main and secondary spaces, the absorption ratio between the two spaces, and aperture size. The resulting energy decay profiles are analyzed using T30/T15 Coupling Coefficient ratios and Bayesian analysis. Coupling Coefficient results show general trends in the effects of the three architectural parameters that match previous research results and the predominant interactive effect between the three variables involving …
Room Acoustics In Coupled Volume Spaces, David T. Bradley, Lily M. Wang
Room Acoustics In Coupled Volume Spaces, David T. Bradley, Lily M. Wang
Lily M Wang
The study of sound in the built environment is finding more awareness in the 21st century. As this awareness has increased, and as computing power has grown, the method of computer modeling for studying room acoustics in such settings as classrooms, offices, and performances spaces has taken great strides in recent years. Of particular interest has been the study of the coupled volume space due to its unique ability to provide contrasting acoustical phenomenon. A coupled volume room is generally defined as a space consisting of a large main volume containing high levels of sound absorption connected through small sonically …
Performance Review Of Indoor Noise Criteria, Lily M. Wang, Erica Eileen Bowden
Performance Review Of Indoor Noise Criteria, Lily M. Wang, Erica Eileen Bowden
Lily M Wang
Currently there are a number of indoor noise criteria used to quantify the level of background noise in rooms, including Noise Criteria (NC), Balanced Noise Criteria (NCB), Room Criteria (RC), Room Criteria Mark II (RC Mark II) and others. This paper reviews the pros and cons of each of these and then compares the values measured in existing classrooms in the Omaha area. The authors are in the process of subjectively comparing these various criteria to determine which method best correlates with human perception. The subjective testing methods and preliminary results are discussed.
Effects Of Acoustic Environments On Speech Comprehension By Native-English-Speaking Listeners, Zhao Peng, Lily M. Wang, Siu Kit Lau
Effects Of Acoustic Environments On Speech Comprehension By Native-English-Speaking Listeners, Zhao Peng, Lily M. Wang, Siu Kit Lau
Lily M Wang
This study investigates the effects of acoustic conditions on speech comprehension, rather than speech intelligibility as often reported in existing literature. Sets of 15-minute-long listening comprehension tests were developed based on the format of the Test of English for International Communication (TOEIC). Each test set includes four types of tasks: matching aural phrases to photographs, selecting appropriate responses to aural questions, and answering questions after listening to conversations (between two talkers) and talks (single talker). Within the Nebraska acoustics test chamber, native-English-speaking participants are asked to perform these tests under 15 acoustic conditions, from combinations of three background noise levels …
Optimum Absorption And Aperture Parameters For Realistic Coupled Volume Spaces Determined From Computational Analysis And Subjective Testing Results, David T. Bradley, Lily M. Wang
Optimum Absorption And Aperture Parameters For Realistic Coupled Volume Spaces Determined From Computational Analysis And Subjective Testing Results, David T. Bradley, Lily M. Wang
Lily M Wang
This project utilizes computational modeling to study the effects of varying two architectural parameters, absorption ratio and aperture size, in a realistic coupled volume concert hall. Coupled volumes have been shown to exhibit non-exponential sound energy decay profiles, referred to as double slope effect. A number of objective metrics (T30/T15, LDT/T10, decay ratio, and ΔL) have been used to quantify the double slope effect of the profiles generated in the virtual hall. T30/T15 and LDT/T10 showed similar trends across all hall configurations, indicating decreasing double slope effect with increasing coupled volume absorption ratio for each aperture size, and producing highest …
Investigations Of Multi-Channel Auralization Technique For Solo Instruments And Orchestra, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel
Investigations Of Multi-Channel Auralization Technique For Solo Instruments And Orchestra, Michelle C Vigeant, Lily M. Wang, Jens Holger Rindel
Lily M Wang
Computer modeling of room acoustics is a useful tool in the design of acoustically sensitive spaces and an important outcome from these programs is auralizations. This study examined the perceived changes in realism and source width when listening to multi-channel auralizations compared to single channel auralizations for both solo instruments and a full orchestra. The first experiment, which examined subjective judgments of auralizations made from solo instruments, showed that perceived realism increased as the number of channels was increased from one to four to thirteen, while the relationship between source width and number of channels was less clear. In the …
Reflector Responses: A Comparison Between Odeon’S Modified Ray Tracing Algorithm And A Filtered Boundary Element Method Model, Jonathan Rathsam, Lily M. Wang, Jens Holger Rindel, Claus Lynge Christensen
Reflector Responses: A Comparison Between Odeon’S Modified Ray Tracing Algorithm And A Filtered Boundary Element Method Model, Jonathan Rathsam, Lily M. Wang, Jens Holger Rindel, Claus Lynge Christensen
Lily M Wang
The biggest challenge for geometrical room acoustic computer models is to capture complex wave phenomena while maintaining the low computational load of the ray tracing algorithm. Special corrections must be added to the ray tracing algorithm to account for wave phenomena such as edge diffraction, which are ignored by classical geometrical acoustics. ODEON, a well-known geometrical computer model, is in the process of upgrading its ray tracing and scattering algorithm. The new algorithm allows users to specify transmission through reflector panel arrays. To aid in the development of ODEON’s new algorithm, its predictions are compared with predictions from a boundary …
Acoustic Communication In Panthera Tigris: A Study Of Tiger Vocalization And Auditory Receptivity, Edward J. Walsh, Lily M. Wang, Douglas L. Armstrong, Thomas Curro, Lee G. Simmons, Joann Mcgee
Acoustic Communication In Panthera Tigris: A Study Of Tiger Vocalization And Auditory Receptivity, Edward J. Walsh, Lily M. Wang, Douglas L. Armstrong, Thomas Curro, Lee G. Simmons, Joann Mcgee
Lily M Wang
To adults and children alike, tigers are one of the best-known members of the animal kingdom. It may be surprising, then, to learn that we have a lot to discover about their hearing and the acoustics of their vocalizations. To help fill in the gaps in our knowledge, we are in the midst of a study that is focused on the characterization of the vocal properties and hearing capabilities of a subset of surviving tiger subspecies, namely the Siberian, Bengal, Sumatran and the Indochinese tigers. We are hoping that our findings will not only add to a deeper understanding of …
Acoustic Radiation From Bowed Violins, Lily M. Wang, Courtney B. Burroughs
Acoustic Radiation From Bowed Violins, Lily M. Wang, Courtney B. Burroughs
Lily M Wang
Nearfield acoustic holography (NAH) is applied to visualize the acoustic radiation from bowed violins across a frequency range from 294 Hz to 3 kHz. These visualizations are employed to localize regions of acoustic radiation from surfaces of violins. Three violins were tested: a common student instrument by Scherl and Roth; Hutchins violin SUS295, which has been the subject of many previous investigations; and a Hutchins mezzo violin from the Violin Octet set of instruments, which is longer, broader and thinner than a standard instrument. The violins were bowed continuously with an open-frame mechanical bowing machine, while NAH measurements were made …
Ab-10-018: The Effects Of Noise From Building Mechanical Systems With Tonal Components On Human Performance And Perception (1322-Rp), Erica E. Ryherd, Lily M. Wang
Ab-10-018: The Effects Of Noise From Building Mechanical Systems With Tonal Components On Human Performance And Perception (1322-Rp), Erica E. Ryherd, Lily M. Wang
Lily M Wang
This study investigated the effects of noise from building mechanical systems with tonal components on human task performance and perception. Six different noise conditions based on in-situ measurements were reproduced in an office-like setting; all were set to approximately the same sound level (47 dBA) but could have one particular tonal frequency (120 Hz, 235 Hz, or 595 Hz) at one of two tonal prominence ratios (5 or 9). Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately 1 hour to each noise condition. Results show that the noise …
Ab-10-019: Human Performance And Perception-Based Evaluations Of Indoor Noise Criteria For Rating Mechanical System Noise With Time-Varying Fluctuations (1322-Rp), Lily M. Wang, Cathleen C. Novak
Ab-10-019: Human Performance And Perception-Based Evaluations Of Indoor Noise Criteria For Rating Mechanical System Noise With Time-Varying Fluctuations (1322-Rp), Lily M. Wang, Cathleen C. Novak
Lily M Wang
The goal of this study was to investigate the effects of noise from building mechanical systems with time-varying fluctuations on human task performance and perception, and to determine how well current indoor noise rating methods account for this performance and perception. Six different noise conditions with varying degrees of time-varying fluctuations, many focused in the low frequency rumble region, were reproduced in an office-like setting. Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately one hour to each noise condition. Results show that the noise conditions with higher sound …
Ab-10-017: Combined Effects Of Noise And Temperature On Human Comfort And Performance (1128-Rp), Dale Tiller, Lily M. Wang, Amy Musser, Matthew Radik
Ab-10-017: Combined Effects Of Noise And Temperature On Human Comfort And Performance (1128-Rp), Dale Tiller, Lily M. Wang, Amy Musser, Matthew Radik
Lily M Wang
This paper summarizes results from an experiment designed to investigate the combined effects of noise and temperature on human thermal comfort and task performance. Thirty subjects (16 females, 14 males) were exposed to all combinations of five thermal conditions (PMV +1 [79.6°F:26.4°C], PMV +0.5 [75.8°F:24.3°C], PMV 0 [72.1°F:22.3°C], PMV -0.5 [68.3°F:20.2°C], and PMV -1 [64.6°F:18.1°C]), three RC noise levels (RC-30, RC-40, and RC-50), and two sound qualities (neutral and rumbly): all sounds mimicked noise from building ventilation systems. After a one-hour adaptation period at each condition, subjects rated their thermal comfort using the ASHRAE Thermal Comfort Scale and the Tenant …
A Review Of Diffuse Reflections In Architectural Acoustics, Jonathan Rathsam, Lily M. Wang
A Review Of Diffuse Reflections In Architectural Acoustics, Jonathan Rathsam, Lily M. Wang
Lily M Wang
Diffuse reflections have received increasing attention in architectural acoustics over the past quarter century. The term diffuse refers to non-specular directions. This paper identifies three mechanisms that cause diffuse reflections. Practitioners have found that changing specular reflections into diffuse reflections can reduce noise and echoes both indoors and outdoors. Developers of acoustical modeling software have also found that modeling diffuse in additional to specular reflections produces more accurate predictions. The final portion of this paper presents results for a study of scattering coefficients in acoustical modeling software.
Appropriate Characterization Of Background Noise Levels In The Workplace, Erica E. Bowden, Lily M. Wang
Appropriate Characterization Of Background Noise Levels In The Workplace, Erica E. Bowden, Lily M. Wang
Lily M Wang
Overall loudness is not the only quality of indoor background noise that affects occupants. The distribution of noise across frequency (pitch), whether or not the noise contains tones, and whether or not the noise changes over time must also be considered. There are several indoor noise criteria systems available to quantify the background noise in rooms, but many of them do not account for these factors. These systems are commonly used by architects and engineers, and often incorporated into manufacturer’s data, design guides, and standards. There is much debate over which of the criteria systems best reflect how occupants will …
Apparatus For Studying Wave Motion And Sound At The University Of Nebraska– Lincoln's “Historical Scientific Instrument Gallery”, Lily M. Wang, M. Eugene Rudd
Apparatus For Studying Wave Motion And Sound At The University Of Nebraska– Lincoln's “Historical Scientific Instrument Gallery”, Lily M. Wang, M. Eugene Rudd
Lily M Wang
The University of Nebraska–Lincoln's “Historical Scientific Instrument Gallery,'' compiled by the second author in 1998, contains approximately 700 inventoried items and may be visited on-line at http://physics.unl.edu/outreach/histinstr/. Amidst the collection are several acoustical instruments that were used in the early 1900s. These include equipment that demonstrate wave motion (traveling wave machine, mercury ripple dish, vibration microscope), wave interference (interference machine), resonance conditions (Helmholtz resonators, vibrating rods, singing flames, sonometer), and sound generation (Galton's whistles, high-frequency tuning forks, large tuning forks, organ pipes, siren saw). A review of the equipment and the history of their use at the University of Nebraska …
Lv-11-C031: Measured Levels Of Hospital Noise Before, During, And After Renovation Of A Hospital Wing, And A Survey Of Resulting Patient Perception, Cassandra H. Wiese, Lily M. Wang
Lv-11-C031: Measured Levels Of Hospital Noise Before, During, And After Renovation Of A Hospital Wing, And A Survey Of Resulting Patient Perception, Cassandra H. Wiese, Lily M. Wang
Lily M Wang
Acoustic conditions in hospitals can negatively influence a patient’s physical and psychological health. This paperreports on noise levels measured before, during, and after renovation of a hospital wing in an Omaha, Nebraska, facility thatregularly receives unsatisfactory noise scores on patient satisfaction surveys. Sound pressure levels were logged every 10seconds over four-day periods in three different locations: at the nurses' station, in the hallway, and in a nearby patient’sroom. The resulting data have been analyzed in terms of A-weighted equivalent sound levels (LAeq) as well as variousexceedance levels (Ln). Results indicate that sound levels did not change much due to the …