Sound Volume Research Articles

Theoretical calculation and test of airborne sound insulation for wooden building floor

To meet objectives such as the sound insulation characteristics of timber structures and the comfort of residents, this study assessed an ordinary floor and three kinds of floating floors (Portuguese cork, graphite polystyrene sound insulation boards and expanded polypropylene plastic foam boards) in the same bedroom of a two-storey light wooden building. Adopting standard white noise and music noise excitation, structural design, theoretical checks and sound insulation tests of the floors were conducted. For the four floor structures, the sound insulation volume, sound pressure distribution characteristic spectrum of the building floor under different noise source environments, the frequency characteristics of the noise source, the multiple relationship of the sound insulation sound pressure level and the sound insulation mechanism were analysed. It was found that the sound pressure multiple of the space separating the upper and lower floors of the building was 8–18 times greater than that of the light wooden floor structure. The airborne sound insulation volume–frequency curves of the four floors, calculated by the transfer matrix method, were consistent with the actual measured values. The sound insulation effect was better in the low and middle frequencies.

Effect of User Personality on Efficacy of a Mental Support System Based on Ambient Intelligence: A Case Study

One solution supporting a healthy mental state for humans is controlling the environment with ambient intelligence technology. We are developing a mental support system for healthy people that automatically changes environmental conditions, such as sound volume and light color, depending on the user’s mental state, which is monitored according to physiological signals such as sympathetic nerve activity. In our previous basic study under laboratory-controlled conditions, the system was applied to improve the user’s concentration level as they performed calculation tasks. Results indicated that the system improved the task performance, but individual variations existed, with some users improving greatly but others much less. For the future practical application of the system, determining the causes of the variation in efficacy is important. Considering that the brain structure and activity differ according to an individual’s personality, we investigated the relationship between the user’s personality and task performance with our system’s support. The results showed a clear correlation between the extraversion score and task performance. Our study presents an example where the system’s efficacy is sensitive to the user’s personality and indicates the importance of considering the user’s personality when designing a mental support system based on ambient intelligence.

Measurement of steam flow rates using a clamp-on ultrasonic flowmeter with various wetness fractions

Most of the heat in industrial plants is supplied by steam. To minimize energy waste, measuring the steam flow rates in existing pipes is important. Clamp-on ultrasonic flowmeters are used for this purpose, for which the sensors are attached to the pipe wall. However, flow conditions that can be used are limited because the signal-to-noise ratio of the ultrasonic signal in a steam flow is low. Furthermore, the steam wetness increases with heat losses, which may affect measurement results. Therefore, flow rate measurements in wet steam flows using clamp-on ultrasonic flowmeters have not been fully established. In this study, steam flow rates with various wetness fractions and system pressures were measured using a laboratory-made clamp-on ultrasonic flowmeter. The results show that flow rates in wet steam could be determined within a 10% error under general conditions in a steam piping system, although the conversion factor from line-average to area-average velocities was calibrated in superheated conditions, and the speed of sound in saturated conditions at each pressure was used. However, the error of the flow rates tended to increase with the wetness fraction and was biased toward positive values. The speed of sound and liquid volume fraction were evaluated at different wetness fractions. The flow rate error due to the change in sound speed was less than 1%, and 1.2% of the flow rates were overestimated owing to the liquid volume fraction. The velocity distribution in wet steam was considered different from that in the superheated steam owing to the existence of the liquid phase, and the change in velocity profile may lead to an overestimation of the steam flow rates in the wet steam condition.

Restrictive measures during COVID-19 pandemic: the impact of face masks and social distancing on communication, physical and mental health of normal hearing subjects

Objective Social distancing and face masks are considered the best tools to prevent COVID-19 spread despite an impact on communication, hearing perception and quality of life. Methods An observational study was performed among a population of normal hearing subjects (NHS) referring to Department of Otorhinolaryngology. Data were collected with a self-administered online questionnaire which included the Italian SF-36 Health Survey Questionnaire referred to face masks use, the Hamilton Rating Scale for Anxiety (HAM-A) and four questions focussed on communication difficulties due to facial masks use and social distancing (COVID-19 restrictions questions, CRQs). Results 200 NHS answered the online survey. Mean age was 40.46 (SD 13.6). The cohort was distributed according to the job performed: 137 were workers in contact with the public (Job in contact with Public, JP), while 63 were people who don’t work with the public (Job Non in contact with Public, JNP). An overall decrease in quality of life, related to the use of face masks, was detected. In fact, significant differences in the SF-36 Health Survey among our sample and the Italian normative sample were observed in 4 over 8 multi-item scales: Physical Functioning (PF), Role Functioning Physical (RP), Social Functioning (SF) and Role Functioning Emotional (RE). Furthermore, a worst general mental health (GMH) score was observed in the JNP group (p = .0008). The CRQs analysis showed that facial masks were more frequently held responsible for communication difficulties compared to social distancing, particularly due to an attenuation of sound volume and difficulties in rendering facial expressions. Significantly higher anxiety scores were reported in the JNP group, according to the HAM-A, although not reaching pathological level. Conclusions An impact on communication and general health perception due to COVID-19 restrictions was referred in a large part of the population with differences between the two groups (JP vs. JNP).

Rapid Assessment of Tree Damage Resulting from a 2020 Windstorm in Iowa, USA

A need to quantify the impact of a particular wind disturbance on forest resources may require rapid yet reliable estimates of damage. We present an approach for combining pre-disturbance forest inventory data with post-disturbance aerial survey data to produce design-based estimates of affected forest area and number and volume of trees damaged or killed. The approach borrows strength from an indirect estimator to adjust estimates from a direct estimator when post-disturbance remeasurement data are unavailable. We demonstrate this approach with an example application from a recent windstorm, known as the 2020 Midwest Derecho, which struck Iowa, USA, and adjacent states on 10–11 August 2020, delivering catastrophic damage to structures, crops, and trees. We estimate that 2.67 million trees and 1.67 million m3 of sound bole volume were damaged or killed on 23 thousand ha of Iowa forest land affected by the 2020 derecho. Damage rates for volume were slightly higher than for number of trees, and damage on live trees due to stem breakage was more prevalent than branch breakage, both likely due to higher damage probability in the dominant canopy of larger trees. The absence of post-storm observations in the damage zone limited direct estimation of storm impacts. Further analysis of forest inventory data will improve understanding of tree damage susceptibility under varying levels of storm severity. We recommend approaches for improving estimates, including increasing spatial or temporal extents of reference data used for indirect estimation, and incorporating ancillary satellite image-based products.

Designing Aedes (Diptera: Culicidae) Mosquito Traps: The Evolution of the Male Aedes Sound Trap by Iterative Evaluation.

Simple SummaryThis study presents a product profile and describes key developmental trial results concerning the invention of the male Aedes sound trap. This trap contains a sound lure which mimics female mosquito wingbeat frequencies to attract male Aedes aegypti. Male Ae. aegypti capture rates were significantly influenced by the presence of, and large variations in size of, a black trap base. Male capture rates were also influenced by reducing the trap entrance below 2.5 cm (1 inch), but not by variations in sound lure volume, between 63–78 dB, or whether the sound lure tone was played continuously or intermittently. No differences were noted in catch rates of male Ae. aegypti in traps using sound lures set to 450 Hz or 500 Hz, but younger adult males were captured at lower rates than some older male groups. Lastly, when the trap was exposed to windy conditions male Ae. aegypti capture rates were affected to varying degrees, depending on trap orientation relative to the wind and whether the wind was continuous or intermittent. The trap profile and behavioural findings associated with this trap development are relevant to ensuring effective surveillance using this new tool, as well as the development of other mosquito traps.Effective surveillance of Aedes aegypti (Linnaeus, Diptera: Culicidae) is critical to monitoring the impact of vector control measures when mitigating disease transmission by this species. There are benefits to deploying male-specific traps, particularly when a high level of catch-specificity is desired. Here, the rationale behind the developmental process of an entirely new trap which uses a sound lure to capture male Ae. aegypti, the male Aedes sound trap (MAST), is presented as a target product profile with findings from developmental trials of key trap components and performance. Trial results suggest that the presence of a black base associated with the trap influenced male catches as did variations in size of this base, to a degree. Trap entrance shape didn’t influence catch rates, but entrance size did. No significant differences in catch rates were found when sound lures were set to intermittent or continuous playbacks, at volumes between 63–74 dB or frequencies of 450 Hz compared to 500 Hz. Additionally, adult males aged 3 days post-eclosion, were less responsive to sound lures set to 500 Hz than those 4 or 6 days old. Lastly, almost no males were caught when the MAST directly faced continual winds of 1.5 ms−1, but males were captured at low rates during intermittent winds, or if the trap faced away from the wind. The developmental process to optimising this trap is applicable to the development of alternate mosquito traps beyond Aedes sound traps and provides useful information towards the improved surveillance of these disease vectors.

Implications of sample size and acquired number of steps to investigate running biomechanics

Low reproducibility and non-optimal sample sizes are current concerns in scientific research, especially within human movement studies. Therefore, this study aimed to examine the implications of different sample sizes and number of steps on data variability and statistical outcomes from kinematic and kinetics running biomechanical variables. Forty-four participants ran overground using their preferred technique (normal) and minimizing the contact sound volume (silent). Running speed, peak vertical, braking forces, and vertical average loading rate were extracted from > 40 steps/runner. Data stability was computed using a sequential estimation technique. Statistical outcomes (p values and effect sizes) from the comparison normal vs silent running were extracted from 100,000 random samples, using various combinations of sample size (from 10 to 40 runners) and number of steps (from 5 to 40 steps). The results showed that only 35% of the study sample could reach average stability using up to 10 steps across all biomechanical variables. The loading rate was consistently significantly lower during silent running compared to normal running, with large effect sizes across all combinations. However, variables presenting small or medium effect sizes (running speed and peak braking force), required > 20 runners to reach significant differences. Therefore, varying sample sizes and number of steps are shown to influence the normal vs silent running statistical outcomes in a variable-dependent manner. Based on our results, we recommend that studies involving analysis of traditional running biomechanical variables use a minimum of 25 participants and 25 steps from each participant to provide appropriate data stability and statistical power.

Phasic activation of the locus coeruleus attenuates the acoustic startle response by increasing cortical arousal

An alerting sound elicits the Acoustic Startle Response (ASR) that is dependent on the sound volume and organisms’ state, which is regulated by neuromodulatory centers. The locus coeruleus (LC) neurons respond to salient stimuli and noradrenaline release affects sensory processing, including auditory. The LC hyperactivity is detrimental for sensorimotor gating. We report here that priming microstimulation of the LC (100-ms at 20, 50, and 100 Hz) attenuated the ASR in rats. The ASR reduction scaled with frequency and 100 Hz-stimulation mimicked pre-exposure to a non-startling tone (prepulse). A rapid (~ 40 ms) EEG desynchronization following the LC stimulation suggested that the ASR reduction was due to elevated cortical arousal. The effects of LC stimulation on the ASR and EEG were consistent with systematic relationships between the ASR, awake/sleep state, and the cortical arousal level; for that matter, a lower ASR amplitude corresponded to a higher arousal level. Thus, the LC appears to modulate the ASR circuit via its diffuse ascending projections to the forebrain saliency network. The LC modulation directly in the brainstem and/or spinal cord may also play a role. Our findings suggest the LC as a part of the brain circuitry regulating the ASR, while underlying neurophysiological mechanisms require further investigation.

Personal Music Players and Hearing Loss: The HUNT Cohort Study.

It is unclear whether the current average use of personal music players (PMPs) including mobile phones has affected hearing in the general population. The association between the use of PMPs and hearing loss was assessed in a large population cross-sectional and follow-up study with the following distribution: cross-sectional (2018): n = 26,606, 56% women, mean age 54 years and 20-year follow-up (baseline 1998): n = 12,115, 57% women, mean age at baseline 43 years. Hearing threshold was determined as pure-tone average over the frequencies 3, 4, and 6 kHz. We used linear regression to assess relationships between hearing threshold and PMP use (yes), duration (1–2/2–6/>6 h per week), or sound volume (low/medium/high), with nonuse as reference. The PMP use increased from 8% in 1998 to 30% in 2018. Compared with nonusers, neither use nor duration was related to hearing threshold. As to sound volume, listening at low levels was associated with better thresholds (−2.5 dB [−4.1 to −0.8]), while listening at high levels was associated with worse thresholds (1.4 dB [0.1 to 2.8]). We adjusted for age, sex, baseline hearing threshold, education, noise exposure, ear infections, head injury, and daily smoking. The association with sound volume was nearly twice as strong when adjusting for hearing threshold at baseline. Accordingly, the possibility of reverse causality was reduced although not eliminated by the follow-up design. This large population study showed no association between normal PMP use and 20-year progression in hearing; however users listening to high levels increased their hearing threshold.

Volumetric and Acoustic Properties of D(+) Glucosamine·HCl and L-Lysine·HCl in Aqueous Solutions at Different Temperatures

In present work, density and speed of sound of aqueous binary mixtures of biologically important amino acid derivatives namely D(+) glucosamine·HCl and L-lysine·HCl have been measured at three different temperatures i.e. (278.15, 288.15 and 298.15) K and in the concentration range of 0.0-0.2 mol kg-1. Using density and speed of sound data, different thermodynamic and acoustic parameters like apparent molar volume (Vφ) and apparent molar isentropic compression (Kφ) of solute have been computed at different temperatures. Speed of sound data have also been used to calculate hydration number (nH) of solute. The temperature dependence of the limiting apparent molar volume of solute has been used to calculate thermal expansion coefficient (α*), apparent molar expansivity (E0 φ) of solute and Hepler’s constant (∂2V0 φ/∂T2). The final outcome of the study has been discussed in terms of various interactions among solute and solvent molecules.

Investigations on Acoustical and Thermal Properties of Ethylene Glycol Based Nickel Oxide Nanofluids: Concentration and Temperature

The acoustical and thermophysical properties of nanofluids is of great importance in heat exchange systems. Thus, these properties of nickel oxide (NiO) nanoparticles dispersed in ethylene glycol (EG) were studied after synthesizing and characterization of NiO nanoparticles. Speed of sound, acoustic impedance and free volume for NiO-EG nanofluids first increased upto 0.6 wt % and then decreased. However, viscosity, adiabatic compressibility and intermolecular free length first decreased upto 0.6 wt % and then increased. The density was observed to increase with increase in concentration and decrease with temperature. Speed of sound, viscosity and acoustic impedance decreases with increase in temperature, whereas, adiabatic compressibility, intermolecular free length and free volume increases. Thermal conductivity of NiO-EG nanofluids increased upto 0.6 wt % followed by its decrease, and it also decreased with the temperature at all concentrations. In conclusion, NiO-EG nanofluids upto 0.6 wt % concentration are very useful for nanofluids applications in thermal systems.

A study on structure and functions of organs involved in the formation of Mongolian Khuumii sound

Khuumii (throat or overtone singing) is a unique form of art derived from the nomadic population of Central Asia, which is a type of singing in which the singer manipulates the resonances (or formants) created as air travels from the lungs, past the vocal folds, and out of the lips to produce a melody. A total of 60 participants, aged 18-60 years (54 men and 6 women), were selected by non-random sampling method using cross-sectional study. X-ray, endoscopy, and sound research method were used in the study, and the composition of blood gas was analysed. X-ray examination determined the state during each different types of Khuumii; Shakhaa and Kharkhiraa. As the basic timbre of Shakhaa Khuumii went up progressively the larynx grew and the compression strength increased, while the basic timbre went down, and the larynx became lower. In the case of Kharkhiraa Khuumii, the larynx position was elevated to a relatively small extent compared to Shakhaa Khuumii and the distance between the sublingual bone and the larynx was large. The sublingual bone trunk lowered during Shakhaa Khuumii, while it was slightly elevated during Kharkhiraa Khuumii. The laryngeal endoscopy evaluated the movement of true and false vocal chords, glottal volume, movements of epiglottis and arytenoid cartilage, and mucosa. Furthermore, the sound frequency is 2-4 times higher than that of normal speech, and sound volume is 0.5-1 times higher. The blood gas composition test showed partial pressure (pO2), and saturation of oxygen (SaO2) decreased after performing Khuumii. In the case of Shakhaa and Kharkhiraa Khuumi, it is appropriate to divide Khuumii into two main types according to structural and functional changes in the organs involved.

Exposure to Excessive Sound Volume: A Major Challenge in the South-Western Nigeria Church Auditoria

The study examines the exposure to excessive sound volume as a major challenge to grapple with in church auditoria in South-western Nigeria. This exposure to excessive sound has become a source of noise pollution and it is dangerous to human health. Data for this paper were gathered through participant observation of musical acoustics in worship auditoria using a Virtual Instrument; a Sound Pressure Level mobile application installed on a mobile phone for sound volume measurement. The equivalent noise level using A-weighting was taken for twenty minutes per day, this was observed for the three different worship services at different dates and time in each of the selected church auditoria during each worship service. The LAeq, T, of each musical session was calculated. Findings show that the worshippers are exposed to average noise levels of 90.29 dB (Threshold of Pain) at every worship service which is higher than the recommended 60dB for normal human ear by World Health Organization (WHO). It was also observed that all the selected church auditoria lack appropriate acoustic treatment which led to sound reflections and severe echo. The paper concludes that the culture of noise pollution has become a social phenomenon in the Nigerian society especially, in church auditoria where loud musical sound is arrogated to power and domination of space. This paper recommends that acceptable optimal standards for sound production either in enclosures or in open spaces be emphasized by the Nigerian local, state and federal governments to effectively control noise for human and societal wellbeing.

Bone-conduction hyperacusis induced by superior canal dehiscence in human: the underlying mechanism

Our ability to hear through bone conduction (BC) has long been recognized, but the underlying mechanism is poorly understood. Why certain perturbations affect BC hearing is also unclear. An example is BC hyperacusis (hypersensitive BC hearing)—an unnerving symptom experienced by patients with superior canal dehiscence (SCD). We measured BC-evoked sound pressures in scala vestibuli (PSV) and scala tympani (PST) at the basal cochlea in cadaveric human ears, and estimated hearing by the cochlear input drive (PDIFF = PSV – PST) before and after creating an SCD. Consistent with clinical audiograms, SCD increased BC-driven PDIFF below 1 kHz. However, SCD affected the individual scalae pressures in unexpected ways: SCD increased PSV below 1 kHz, but had little effect on PST. These new findings are inconsistent with the inner-ear compression mechanism that some have used to explain BC hyperacusis. We developed a computational BC model based on the inner-ear fluid-inertia mechanism, and the simulated effects of SCD were similar to the experimental findings. This experimental-modeling study suggests that (1) inner-ear fluid inertia is an important mechanism for BC hearing, and (2) SCD facilitates the flow of sound volume velocity through the cochlear partition at low frequencies, resulting in BC hyperacusis.

Fatigue-related changes in vertical impact properties during normal and silent running

ABSTRACT Running while minimizing sound volume can reduce vertical impact loading, potentially reducing injury risks. Fatigue can increase the vertical loading rate during running, but it is unknown whether fatigue influences silent running similarly. This study aimed to explore the differences in vertical impact properties during normal and silent running following a fatiguing task. Seventeen participants performed overground running (normal and silent) before and after a fatiguing running protocol. Running footfall sounds were collected using four microphones surrounding a force platform on the track. Peak impact sound, vertical impact peak force (IPF), instantaneous (VILR), and average vertical loading rate (VALR) were compared from Pre- to Post-fatigue. Peak impact sounds were significantly greater for fatigued runners during normal running when compared to silent running (p < 0.005), without changes in force parameters. Moreover, peak impact sounds, IPF, VILR, and VALR from normal running were greater when compared to silent running (p < 0.001), both fresh or fatigued. Our results suggest that fatigue may not compromise silent running technique, which may be relevant to reduce early vertical impact loading. Therefore, runners seeking to modify running style towards the reduction of impact loading may benefit from including silent running drills in their training sessions.

Prediction models of knot volume inside the stem for Korean pine plantation

Based on 1207 knots from 49 sample trees of 29 standard plots of Korean pine plantations in Linkou and Dongjingcheng Forest Bureau of Heilongjiang Province, China, we extracted longitudinal sections of knots using the image processing software Digimizer and represented the shape of knots using two-dimensional scatter plots. According to the two-dimensional scatter plots, knots of Korean pine plantation were divided into three types: 1) alive knots (whole knot contained only sound knot portion); 2) non-occluded dead knots (whole knot contained both sound and loose knot portions); 3) occluded dead knots (the sound and loose portion of the knot were partially occluded by the bark). For all the three types of knots, the volume of sound knot was calculated by mathematical integral of the sound knot shape equation. The volume of loose knot was calculated using the volume equation of a cylinder. The total volume of knots was calculated as the sum of sound and loose knot volume. Finally, based on knot variables (diameter, relative height and total length of knots) and tree variable (diameter at breast height), we established the prediction models for sound knot volume, loose knot volume, and total volume of knot using the linear mixed model at plot level and tree level. Compared with fixed-effects model, the mixed effects models of the volume of sound knot, loose knot, and total knots provided more accurate parameter estimation, more uniform residual distribution, and higher model fitting precision. The validation results showed that prediction precision of each fixed-effect model was higher than 90%, while that of the mixed models with plot and tree effect was above 93%, indicating that the established model could well predict the volume of knot for Korean pine plantation.

The Relationship Between Smartphone-Recorded Environmental Audio and Symptomatology of Anxiety and Depression: Exploratory Study.

BackgroundObjective and continuous severity measures of anxiety and depression are highly valuable and would have many applications in psychiatry and psychology. A collective source of data for objective measures are the sensors in a person’s smartphone, and a particularly rich source is the microphone that can be used to sample the audio environment. This may give broad insight into activity, sleep, and social interaction, which may be associated with quality of life and severity of anxiety and depression.ObjectiveThis study aimed to explore the properties of passively recorded environmental audio from a subject’s smartphone to find potential correlates of symptom severity of social anxiety disorder, generalized anxiety disorder, depression, and general impairment.MethodsAn Android app was designed, together with a centralized server system, to collect periodic measurements of the volume of sounds in the environment and to detect the presence or absence of English-speaking voices. Subjects were recruited into a 2-week observational study during which the app was run on their personal smartphone to collect audio data. Subjects also completed self-report severity measures of social anxiety disorder, generalized anxiety disorder, depression, and functional impairment. Participants were 112 Canadian adults from a nonclinical population. High-level features were extracted from the environmental audio of 84 participants with sufficient data, and correlations were measured between the 4 audio features and the 4 self-report measures.ResultsThe regularity in daily patterns of activity and inactivity inferred from the environmental audio volume was correlated with the severity of depression (r=−0.37; P<.001). A measure of sleep disturbance inferred from the environmental audio volume was also correlated with the severity of depression (r=0.23; P=.03). A proxy measure of social interaction based on the detection of speaking voices in the environmental audio was correlated with depression (r=−0.37; P<.001) and functional impairment (r=−0.29; P=.01). None of the 4 environmental audio-based features tested showed significant correlations with the measures of generalized anxiety or social anxiety.ConclusionsIn this study group, the environmental audio was shown to contain signals that were associated with the severity of depression and functional impairment. Associations with the severity of social anxiety disorder and generalized anxiety disorder were much weaker in comparison and not statistically significant at the 5% significance level. This work also confirmed previous work showing that the presence of voices is associated with depression. Furthermore, this study suggests that sparsely sampled audio volume could provide potentially relevant insight into subjects’ mental health.

DETERMINATION OF SOUND TRANSMISSION COEFFICIENT OF GYPSUM PARTITION WALLS INSULATED BY CELLUBOR™

One of the biggest problems of using public spaces for constructions, such as high-rise buildings, offices, hospitals, and hotels, is noise caused by sound transmission through the lightweight partition walls used to divide volumes. In this study, experiments were carried out to determine the sound transmission coefficient of lightweight gypsum partition walls insulated by CelluBor. Experiments were performed in an anechoic test chamber consists of two separate cells. One cell was used as the sound source, and the other one was used as the receiver cell. A total of 12 samples were used in the experimental studies, which were categorized into four separate groups. The main features that distinguished these groups from each other were the profile height used in the samples and the number of gypsum board layers used on each side of the profiles. In addition, one blank (no insulation) sample, one half filled, and one fully filled with insulation material were used for each test group. The test samples were placed between two cells. The sound volume of the sound source was measured separately in dB in both cells, and the sound transmission coefficients of 12 different samples were determined. It was observed that the most efficient results were obtained only when half of the profile height was filled with the CelluBor material. The use of a composite material consists of boron and waste materials such as CelluBor as sound insulation material in lightweight partition walls can affect the sound transmission coefficient greatly.

Nonlinear regression model for predicting environmental traffic noise

Transport is an essential activity for urban life and for the economy, however, bad planning of the city script causes some movement in some places, causing excessive noise levels generated by road traffic. We aim to present a mathematical model that represents the relationship between the equivalent level of sound and vehicle volume quantities using the nonlinear logistic regression model in order to facilitate decision-making in relation to urban planning. We collected the data of sound pressure and vehicle volume for ten days during five hours totaling a collection of 50 hours, with a total of 180 thousand data of sound pressure level. The place of data collection is a highway that passes through the city of Maringa, in Parana, being an intense traffic highway. The results show the performance of the proposed model were differences between measured and predicted traffic noise levels ranged from -0.3 dB (A) to +0.3 dB (A) and the mean difference was -0.006 dB (A). The proposed road traffic noise forecasting model can be used as a decision support tool in urban planning, considering the same boundary conditions as the road study.

Speed of Sound and Apparent Molal Volume Approach to Study the Ion-Solvent Interactions in Pharmaceutically Important Liquid Systems

Presence of zinc ion and lactose in different pharmaceutical compositions have been inspired to investigate the ion-solvation and related interactions among the components in solution media. This study has been carried out by the measurements of ultrasonic velocity, viscosity and density for the binary solutions of zinc sulphate (ZnSO4) in lactose-water mixed solvent systems at 303.15, 308.15, 313.15 K temperature and at atmospheric pressure. Different thermo-acoustic parameters such as isentropic compressibility, apparent molal volume, solvation number, free volume, internal pressure etc., have been evaluated from the measured values. All these parameters have been analyzed in the light of molecular interactions from their variations against concentration as well as temperature. Presence of ion-solvation and structure promoting nature of solute are the major findings in the present investigation. Besides, it also reveals that the ion-solvation decreases as the temperature increases.