scholarly journals Sound Performances of Partition Board from Waste Materials

2021 ◽  
Vol 920 (1) ◽  
pp. 012011
Author(s):  
U Kassim ◽  
S A Nur ◽  
M N Kamarudin ◽  
M A Rahim
Keyword(s):  
Noise Reduction ◽  
High Intensity ◽  
High Frequency ◽  
Low Frequency ◽  
Test Point ◽  
Sound Level ◽  
Waste Materials ◽  
Horizontal Line ◽  
Low Intensity ◽  
Reduction Coefficient

Abstract This study is on the sound performances of a selected number of partition boards in Industrialised Building System (IBS) buildings. The proposed bespoke board were made from squandered or waste materials, namely, coconut shells and newspapers. Each board had been tested for six different distances from the speaker in four different levels of sound, changing the level of the sound frequency. Thereon, the results were analysed. The average result of each board with various distances from the sound source, starting from 0 cm to 220 cm, was combined into under one sound level. The percentage of the noise reduction coefficient is designated by the vertical line whereas the levels of the sound is designated by the horizontal line. Point 1 stands for the low frequency and low intensity test. Point 2 stands for low frequency and high intensity test. The board that is being made of 80% coconut shell, 15% cement and 5% newspaper has an average of noise reduction coefficient of 0.21 in low frequency and low intensity, 0.21 in low frequency and high intensity, 0.24 in high frequency, high intensity and 0.12 in high frequency low intensity.

Appropriate electrode sites and electrical characteristics for TENS

2014 ◽  
Keyword(s):  
Social Factors ◽  
High Intensity ◽  
High Frequency ◽  
Low Frequency ◽  
Electrical Characteristics ◽  
Nerve Fibres ◽  
Low Intensity ◽  
Factors Influencing ◽  
Electrode Positioning ◽  
Low Threshold

The success of TENS treatment depends on the use of safe and appropriate TENS technique. Uncertainty about optimal TENS technique is due in part to the variety of possible electrode positions and electrical characteristics that can be chosen for treatment. Conventional TENS uses low-intensity, high-frequency currents to activate low-threshold afferent nerve fibres in the skin. AL-TENS uses high-intensity, low-frequency currents to generate non-painful phasic muscle contractions (twitching). The purpose of this chapter is to discuss the principles that underpin the use of safe and appropriate electrode sites and electrical characteristics during TENS. The chapter covers how to choose between conventional and AL-TENS, the appropriate electrode positioning for conventional TENS and AL-TENS including instances where AL-TENS may be more beneficial than conventional TENS, appropriate choice of electrical characteristics for stimulation, and biological, psychological, and social factors influencing response to TENS

scholarly journals Cochlear compound action potentials from high-level tone bursts originate from wide cochlear regions that are offset toward the most sensitive cochlear region

2019 ◽  
Vol 121 (3) ◽  
pp. 1018-1033 ◽  
Author(s):  
C. Lee ◽  
J. J. Guinan ◽  
M. A. Rutherford ◽  
W. A. Kaf ◽  
K. M. Kennedy ◽  
...  
Keyword(s):  
High Frequency ◽  
Action Potentials ◽  
Tuning Curve ◽  
Low Frequency ◽  
Sound Level ◽  
Frequency Tone ◽  
Compound Action Potentials ◽  
High Level ◽  
Level Tone ◽  
Compound Action

Little is known about the spatial origins of auditory nerve (AN) compound action potentials (CAPs) evoked by moderate to intense sounds. We studied the spatial origins of AN CAPs evoked by 2- to 16-kHz tone bursts at several sound levels by slowly injecting kainic acid solution into the cochlear apex of anesthetized guinea pigs. As the solution flowed from apex to base, it sequentially reduced CAP responses from low- to high-frequency cochlear regions. The times at which CAPs were reduced, combined with the cochlear location traversed by the solution at that time, showed the cochlear origin of the removed CAP component. For low-level tone bursts, the CAP origin along the cochlea was centered at the characteristic frequency (CF). As sound level increased, the CAP center shifted basally for low-frequency tone bursts but apically for high-frequency tone bursts. The apical shift was surprising because it is opposite the shift expected from AN tuning curve and basilar membrane motion asymmetries. For almost all high-level tone bursts, CAP spatial origins extended over 2 octaves along the cochlea. Surprisingly, CAPs evoked by high-level low-frequency (including 2 kHz) tone bursts showed little CAP contribution from CF regions ≤ 2 kHz. Our results can be mostly explained by spectral splatter from the tone-burst rise times, excitation in AN tuning-curve “tails,” and asynchronous AN responses to high-level energy ≤ 2 kHz. This is the first time CAP origins have been identified by a spatially specific technique. Our results show the need for revising the interpretation of the cochlear origins of high-level CAPs-ABR wave 1. NEW & NOTEWORTHY Cochlear compound action potentials (CAPs) and auditory brain stem responses (ABRs) are routinely used in laboratories and clinics. They are typically interpreted as arising from the cochlear region tuned to the stimulus frequency. However, as sound level is increased, the cochlear origins of CAPs from tone bursts of all frequencies become very wide and their centers shift toward the most sensitive cochlear region. The standard interpretation of CAPs and ABRs from moderate to intense stimuli needs revision.

THE EFFECT OF HIGH AND LOW FREQUENCY CORTICAL STIMULATION WITH A FIXED OR A POISSON DISTRIBUTED INTERPULSE INTERVAL ON CORTICAL EXCITABILITY IN RATS

2014 ◽  
Vol 24 (02) ◽  
pp. 1430005 ◽  
Author(s):  
INE BUFFEL ◽  
ALFRED MEURS ◽  
ROBRECHT RAEDT ◽  
VEERLE DE HERDT ◽  
LEEN DECORTE ◽  
...  
Keyword(s):  
High Frequency ◽  
Refractory Epilepsy ◽  
Cortical Excitability ◽  
Low Frequency ◽  
Cortical Stimulation ◽  
Interpulse Interval ◽  
Motor Cortex Stimulation ◽  
Low Intensity ◽  
Promising Treatment ◽  
Neocortical Epilepsy

Neurostimulation is a promising treatment for refractory epilepsy. We studied the effect of cortical stimulation with different parameters in the rat motor cortex stimulation model. High intensity simulation (threshold for motor response - 100 μA), high frequency (130 Hz) stimulation during 1 h decreased cortical excitability, irrespective of the interpulse interval used (fixed or Poisson distributed). Low intensity (10 μA) and/or low frequency (5 Hz) stimulation had no effect. Cortical stimulation appears promising for the treatment of neocortical epilepsy if frequency and intensity are high enough.

Wind Noise Reduction for Outdoor Measurement Microphones With Windscreens

2008 ◽  
Author(s):  
Z. C. Zheng ◽  
Ying Xu
Keyword(s):  
Noise Reduction ◽  
High Frequency ◽  
Low Frequency ◽  
High Flow ◽  
Low Flow ◽  
Computational Techniques ◽  
Wind Noise ◽  
Flow Resistivity ◽  
Materials Used ◽  
Wind Noise Reduction

In this study, effects of windscreen material property on wind noise reduction are investigated at different frequencies of incoming wind turbulence. The properties of porous materials used for the windscreen are represented by flow resistivity. Computational techniques are developed to study the detailed flow around the windscreen as well as flow inside the windscreen that uses a porous material as the medium. The coupled simulation shows that for low-frequency turbulence, the windscreens with low flow resistivity are more effective in noise reduction. Contrarily, for high-frequency turbulence, the windscreens with high flow resistivity are more effective.

scholarly journals High Frequency Non-Invasive Stimulation Over the Spine: Effects on Mood and Mechanical Pain Tolerance in Normal Subjects

1997 ◽  
Vol 10 (2-3) ◽  
pp. 61-65 ◽  
Author(s):  
A. D. Towell ◽  
D. Williams ◽  
S. G. Boyd
Keyword(s):  
High Intensity ◽  
High Frequency ◽  
Healthy Subjects ◽  
Normal Subjects ◽  
Pain Tolerance ◽  
Left Shoulder ◽  
Cutaneous Stimulation ◽  
Non Invasive ◽  
Low Intensity ◽  
Clinical Pain

We investigated the effects of non-invasive high frequency (625Hz) stimulation over the spine on mechanical pain tolerance and subjective mood. Sixty healthy subjects were divided equally into three groups receiving either high intensity (250 V), low intensity (3–4 V) or sham electrical stimulation directly over the spinal cord for 30 minutes. Following high intensity stimulation, subjects felt significantly more elated, leisurely and less tense and, contrary to reports on patients with clinical pain, had lower mechanical pain tolerances. There were no correlations between changes in mood and changes in mechanical pain tolerances. These findings contrasted with the lack of any significant differences in mood or mechanical pain tolerances in a second study where 20 subjects received either high intensity or sham stimulation across the left shoulder joint. The results indicate that decreases in mechanical pain tolerance are independent of changes in mood following non-invasive high frequency, high intensity cutaneous stimulation but that both effects are dependent on that stimulation being applied over the spine.

scholarly journals Changes in Electroencephalography by Modulation of Interferential Current Stimulation

2020 ◽  
Vol 10 (17) ◽  
pp. 6028
Author(s):  
Sung-Hyoun Cho ◽  
Seon-Chil Kim
Keyword(s):  
Young Adults ◽  
Cerebral Cortex ◽  
High Frequency ◽  
Pain Perception ◽  
Low Frequency ◽  
Low Intensity ◽  
Stimulation Parameters ◽  
Stimulation Level ◽  
Beta Power ◽  
Interferential Current

Interferential current (IFC) stimulation can alter pain perception. This study aimed to investigate the effects of IFC stimulation on motor cortex signals and observe how electroencephalography changes depend on IFC stimulation parameters. Forty-five healthy adults were divided into high frequency (HF)–low intensity (LI), HF–high intensity (HI), and low frequency (LF)–HI groups to compare their electroencephalography before, immediately after, and 30 min after current stimulation. The changes in relative beta power according to the intervention time showed significant differences between the HF–LI and HF–HI, as well as the LF–HI and HF–HI, groups in the C3 and P3 regions immediately after IFC stimulation. Similarly, the gamma band showed significant differences according to the intervention time between the LF–HI and HF–HI groups in the P3 region immediately following IFC intervention. For relative theta power, the interaction between group and time was significantly different in the Fp2, F3, F4, C3, C4, and P4 regions. Based on these results, we were able to map the activation in cerebral cortex regions according to the stimulation level, confirming changes in electroencephalogram activation through peripheral nerve stimulation. This study provides a foundation for future applications for selectively controlling feedback at a proper stimulation level in young adults.

Random Noise Reduction Based on Ensemble Empirical Mode Decomposition and Wavelet Threshold Filtering

2012 ◽  
Vol 518-523 ◽  
pp. 3887-3890 ◽  
Author(s):  
Wei Chen ◽  
Shang Xu Wang ◽  
Xiao Yu Chuai ◽  
Zhen Zhang
Keyword(s):  
Noise Reduction ◽  
Empirical Mode Decomposition ◽  
High Frequency ◽  
Reduction Method ◽  
Random Noise ◽  
Low Frequency ◽  
Ensemble Empirical Mode Decomposition ◽  
Intrinsic Mode Functions ◽  
Mode Decomposition ◽  
Eemd Method

This paper presents a random noise reduction method based on ensemble empirical mode decomposition (EEMD) and wavelet threshold filtering. Firstly, we have conducted spectrum analysis and analyzed the frequency band range of effective signals and noise. Secondly, we make use of EEMD method on seismic signals to obtain intrinsic mode functions (IMFs) of each trace. Then, wavelet threshold noise reduction method is used on the high frequency IMFs of each trace to obtain new high frequency IMFs. Finally, reconstruct the desired signal by adding the new high frequency IMFs on the low frequency IMFs and the trend item together. When applying our method on synthetic seismic record and field data we can get good results.

Variations in broadband seismic noise at IRIS/IDA stations in the USSR with implications for event detection

1990 ◽  
Vol 80 (6B) ◽  
pp. 2072-2088 ◽  
Author(s):  
Holly K. Given
Keyword(s):  
Noise Reduction ◽  
High Frequency ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Time Of Day ◽  
Signal Frequency ◽  
Seasonal Effect ◽  
Noise Levels ◽  
Power Spectral ◽  
Lower Noise

Abstract Ambient noise conditions at four IRIS/IDA sites in the USSR are characterized from 0.01 to 100 Hz as part of a study to ascertain the utility of broadband three-component seismic stations in monitoring regional Eurasian seismicity. Estimates of the power spectral density of noise levels were computed for a 5-day period in two seasons (winter and summer), at two times of the day. Of these periods, lower noise conditions were found at night in the summer. In general, at 1 Hz and above, noise levels and their variations correlate predictably with the soundness of vault construction and the proximity of the station to civilization. Absolute noise levels at the IRIS/IDA/USSR sites range from a high of about −120 dB to a low of −155 dB relative to (1 m/s2)2/Hz, between 1 and 5 Hz. A time-of-day variation in noise was observed at all sites, with noise levels during the work day ranging from 7 to 14 dB higher than night levels, depending on the site. This effect was observed only for frequencies above about 1 Hz. Observed seasonal variations (winter versus summer) are highly station dependent, although the seasonal effect is restricted to frequencies below 1 Hz and is in general centered on the microseism peak (0.1 to 0.2 Hz). Below 0.1 Hz, noise levels are influenced by the thermal and barometric isolation of the site. Low-frequency levels were not studied below 0.01 Hz. Minimum detectable magnitudes are estimated for the IRIS/IDA stations using the observed noise levels over 1 Hz. In general, a magnitude 3 event should be detectable at 1,000 km by all stations under night noise conditions if the dominant signal frequency is 1 Hz; the magnitude estimates increase with increasing frequency. These detectability estimates assume a conservative signal-to-noise ratio of 6. High-frequency data recorded by independent equipment co-located with the IRIS/IDA system during a 2-week experiment allow estimation of noise levels at the sites up to 100 Hz. Borehole versus surface noise levels recorded during the high-frequency experiment showed significant noise reduction (20 dB) can be achieved by borehole deployment at sites with exposed surface vaults. With well-isolated surface vaults, borehole noise reduction is about a factor of 2. Absolute noise levels between 1 to 10 Hz observed at IRIS/IDA/USSR sites are systematically higher than average NORESS noise by about 7 dB to 25 dB, depending on the station.

Theoretical End Experimental Evaluation of Perforations Effect on Sound Insulation

2017 ◽  
Author(s):  
Olga Khrystoslavenko ◽  
Raimondas Grubliauskas
Keyword(s):  
Noise Reduction ◽  
High Frequency ◽  
Sound Absorption ◽  
Low Frequency ◽  
Experimental Methods ◽  
Glass Wool ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Frequency Noise ◽  
Sound Reduction

To design a sound-absorbing panel, it is important to identify factors that affect the maximum sound absorption of low, middle and high frequency sounds. Perforation effect is very important for the noise-reducing and noiseabsorbing panels. Perforations are often used for sound reduction. Experimental data shows that the perforation is very effective to absorb low-frequency noise. In the presented study, influence of perforation coefficient of noise reduction was analyzed with theoretical and experimental methods. The experiments were conducted in noise reduction chamber using an perforated construction with glass wool filler. Sound reductions index of 15 dB indicates good acoustic properties of the panel.

Sign in / Sign up

Export Citation Format

Share Document