Design and Development of a Hair-like Sensor with Bridge-Type Flexible Amplification Mechanisms.

Compared with lever-type amplification mechanisms, bridge-type flexible amplification mechanisms have advantages in terms of amplification ratio and structural compactness. Therefore, they can effectively replace the lever-type amplification mechanism in the existing hair-like sensors and realize the development of miniature hair-like sensors with high sensitivity. With that in mind, a highly sensitive hair-like sensor based on a bridge-type amplification mechanism with distributed flexibility is presented to measure the airflow rate. First, the structural composition and operating principle of the hair-like sensor are described. Then, detailed design and analysis of the hair-like sensor are carried out, focusing on the design of the hair post structure, amplification mechanism, and resonator. Furthermore, the designed hair-like sensor is processed and prepared, and some experimental studies are conducted. The experimental results demonstrate that the developed hair-like sensor can measure the airflow rate with high sensitivity up to 8.56 Hz/(m/s)2. This provides a new concept for the structural design of hair-like sensors and expands the application of bridge-type flexible amplification mechanisms in the field of micro/nano sensors.

Influence of Airflow Rate and Stimulus Concentration on Olfactory Event-Related Potentials (OERP) in Humans.

Although the association between odor concentration and olfactory event-related potential (OERP) has been studied, less is known about the influence of airflow on OERP. The aim of this study was to investigate the influence of airflow rate and stimulus concentration on OERP in humans. Electroencephalogram data were collected from young healthy volunteers (n = 17) in separate sessions where 2-phenylethanol (PEA) was delivered in the following conditions: 8 L/min 50% v/v, 8 L/min 30% v/v, 4 L/min 100% v/v, and 4 L/min 60%v/v. Odor concentrations are referred to the %v/v achieved with air dilution and was not measured in the nose. Odor intensity ratings were recorded immediately after stimulus presentation. Data recorded at 5 electrodes (Fz, Cz, Pz, C3, and C4) were pooled and analyzed using both time-domain averaging and single-trial time-frequency domain approaches. Higher airflow rate significantly increased intensity ratings (F = 10.98, P < 0.01), and improved the signal-to-noise-ratio (F = 5.42, P = 0.025). Results from time-frequency analysis showed higher concentration versus lower concentration increased brain oscillations in the slow frequency band (1-3 Hz) at 0-600 ms; while higher airflow rates versus lower airflow rate increased theta-band oscillations (300-600 ms and 5-9 Hz) and decreased delta-band oscillations at 900-1500 ms after stimulus onset. In conclusion, compared to stimulus concentration, airflow rate was associated with improved OERP quality and more pronounced responses. The results suggest that intensity ratings and OERP are strongly related to the steepness of stimulus onset. High airflow rates are suggested for odor delivery in order to record OERP.

Interzonal airflow rates for use in near-field far-field workplace concentration modeling.

Interzonal air flow rates (ß) for a workspace above a table were measured in 12 indoor air spaces using an experimental apparatus simulating a vapor release into an occupied near zone. The near field was modeled as a 0.32 m3 rectangular cube volume 0.60 m high above the 0.60 m × 0.90 m table. A total of 74 experimental measurements of ß were made. The apparatus consisted of photoionization detectors measuring concentrations of acetone around an evaporating liquid surface with a robot arm simulating worker motion in the near field. The vapor release rate and the resulting concentrations were used in a near-field far-field (NF-FF) model to calculate ß. Measures of mixing within the near-field supported the assumption of the NF-FF model that the near field is well-mixed. Measured values of ß ranged from 0.4-19 m3/min with an average of 4.8 m3/min. This corresponds to 1.2-59 air changes per minute in the near field and an average of 15 air changes per minute. The values of ß were log normally distributed with a geometric mean of 3.4 m3/min and a geometric standard deviation of 2.3. The 95% confidence interval on the geometric mean of ß was 2.8-4.2 m3/min. The product of the random air speed in the room and one half of the near-field free surface area was shown to be a good method of determining ß. There was a slight correlation seen between room volume and ß, but the effect size was small. Room air change rate was not found to be correlated with ß. The observed distribution of ß will be helpful in selecting values for interzonal airflow rate in NF-FF modeling of worker exposures.

Effect of airflow rate on droplet deposition of an impinging-jet inhaler in the human respiratory tract.

This paper presents a numerical investigation to understand the transport and deposition of sprays emitted by an impinging-jet inhaler in the human respiratory tract under different inhalation flow rates. An injection model is used for the numerical simulations considering the spreading angles of the spray in the two directions, which are measured from experiments. The model parameter is adjusted to match the mean droplet size measured in the previous experiment. A time-varying sinusoidal inhalation flow rate is utilized as airflow conditions, which is closer to the actual situation when using an inhaler. The results demonstrate that the inhalation airflow rate significantly affects the spray's transport behavior and deposition results in the respiratory tract. Both excessively high and low inhalation flow rates lead to an increase in deposition in the mouth-throat. A moderate inhalation flow rate reduces throat deposition while maximizing lung deposition. Higher inhalation flow rates enable faster delivery of the droplets to the lungs, whereas lower inhalation flow rates achieve a more uniform deposition over time in the lungs. The amount of deposition in different parts of the lung lobes follows a fixed order. This study provides valuable insights for optimizing the inhalation flow rate conditions of the impinging-jet inhaler for clinical applications.

Effects of mixed hardwoods dust on respiratory function and blood immunoglobulin levels in wood workers.

Background: Occupational exposure to wood dust, generated by various individual wood species, both softwood and hardwood, has been extensively documented as a causative factor for reduced lung function, frequent respiratory symptoms, and increased immunological responses in wood workers. This study explores the impact of wood dust from mixed tropical hardwood species on lung function, respiratory symptoms, and Immunoglobulin (Ig) E and G levels. Methods: A cross-sectional study was conducted among wood workers at the Accra Timber Market and a control group from the University of Ghana. Particulate matter (PM) was sampled using a Minivol Sampler set to a flow rate of 5 l/min. Respiratory symptoms were assessed using questions adapted from the British Medical Research Council (MRC) questionnaire (1960). Lung volumes and airflow rates were measured using a spirometer. Total serum IgE and IgG levels were quantified using ELISA. Results: No significant differences were observed between the wood workers and the controls for demographic variables. Wood workers exhibited a significantly higher prevalence of respiratory symptoms, particularly rhinitis, with many reporting the absence of symptoms during holidays. Lung function parameters (VC, FEV1, FEV1%, PEFR, and FEF25-75%) were significantly reduced (p < 0.05) in wood workers. A significant negative correlation was noted between lung function parameters and years of exposure to wood dust. Wood workers showed significantly elevated levels (p < 0.05) of IgG and IgE. Conclusion: The study findings suggest that exposure to mixed tropical hardwood dust induces elevated blood IgE and IgG levels, along with non-allergic respiratory function abnormalities.

Conversion of cud and paper waste to biochar using slow pyrolysis process and effects of parameters.

A series of laboratory studies were undertaken in Gondar to explore the effects of temperature, air mass flow rate, heating rate, and residence duration on cud and waste paper char yields in slow pyrolysis. Cud and waste paper were burned at a low pyrolysis temperature to generate biochar (167 °C). The rate of decomposition depends on the feedstock and the process conditions. The biochar yield is mostly governed by the applied regulated temperature and airflow rate, according to the data. During the experiment, the main airflow rate delays the pyrolysis process. The temperature rises when both the primary and secondary air inlets open at the same time, resulting in lesser biochar output. The experiment was carried out at a slow pyrolysis temperature of 167 °C, with 15% biomass moisture, 60% humidity, and a 0.35-1.5 kg/s air mass flow rate. At this temperature, 30 kg of feedstock, cup, and paper in the reactor generate 10 kg-23kg and 10-20 kg of biochar, respectively, at a 0.35 m/s airflow rate. As the airflow rate increases within the restricted values, a temperature gradient appears and tends to increase. However, as the pyrolysis temperature and airflow rate rise, the biochar yield decreases.

Effects of airflow rate distribution and nitrobenzene removal in an aquifer with a low-permeability lens during surfactant-enhanced air sparging.

The application of surfactant-enhanced air sparging (SEAS) in heterogeneous aquifers has received increasing attention. In this study, a two-dimensional laboratory visualization device was used to study the migration and distribution mechanism of airflow and the nitrobenzene removal effect in an aquifer with a low-permeability lens during AS and SEAS. Experimental results showed that the surfactant significantly reduced the blocking effect of the geological interface on airflow, and the ΔPe (the air entry pressure difference between the background media and the lens) value of the geological interface decreased from 1.1 kPa to 0.3 kPa when the surfactant concentration was 800 mg/L. When the surfactant injection location was at the center of the lens and the injection volume was 1 PV (pore volume of the lens), part of the airflow entered the lens through its below interface, which clearly improved the nitrobenzene removal inside and above the lens compared with AS remediation. However, when SEAS remediation was 24 h, the surfactant redistribution caused by air sparging resulted in the airflow entering the lens to bypass the lens again, which changed the spatial distribution of airflow rate and was not conducive to the continuous removal of nitrobenzene inside the lens.

Retest Reliability for Complete Airway Interruption Systems of Aerodynamic Measurement.

INTRODUCTION: Measures of subglottal pressure (Ps), phonation threshold pressure (PTP), and laryngeal resistance (LR) can be used as indicators of vocal cord disorders. The gold standard non-invasive measurement uses labial interruption, which has been shown to have reliability inconsistencies. Mechanical interruption methods have demonstrated promise in measurement reliability. The goal of the present study is to compare retest reliability of labial and mechanical interruption methods. METHODS: 55 subjects aged 18-69 participated. Ten trials were performed for each method. For labial interruption, subjects produced five labial plosives at comfortable and quiet volumes. For mechanical interruption, subjects produced a sustained /α/ while a balloon valve interrupted phonation five times. Thirty subjects completed a second study visit identical to the first approximately two weeks (15 days ± 3.76) after the first visit. Ps, PTP, mean airflow rate, and LR were determined for each subject and retest reliability for each was analyzed. RESULTS: The percent difference in measurement results for test-retest of Ps were 12.88% ± 10.15 for mechanical interruption and 27.56% ± 17.14 for labial interruption (P = 0.0003). The percent difference for PTP measurements were 21.46% ± 16.01 for mechanical and 17.04% ± 14.62 (P = 0.3372) for labial. Intra-subject coefficients of variation of Ps were 0.086 ± 0.046 for mechanical and 0.161 ± 0.078 for labial (P < 0.0001). For PTP, the coefficients were 0.177 ± 0.083 for mechanical and 0.186 ± 0.091 for labial (P = 0.5402). Lastly, for LR (Ps divided by mean airflow rate) the percent differences were 14.33% ± 10.06 for mechanical and 53.87% ± 43.19 for labial (P < 0.0001) with intra-subject variability of 0.115 ± 0.050 for mechanical and 0.287 ± 0.222 for labial (P < 0.0001). CONCLUSIONS: Ps and LR measured using mechanical interruption showed more consistency for both retesting across separate study visits and intra-subject variability. PTP was similar in retesting and intra-subject variability. Continued work to improve mechanical interruption techniques is warranted as these methods offer higher reliability and consistency than the labial interruption methods.

Biomass energy conversion in a gasifier for injera baking mitad application.

The performance of gasification for Injera baking was explored in this study, as well as the effects of moisture content, and primary and secondary airflow rates. Primary air is used in the reactor of a biomass gasifier, which creates syngas that is burned by secondary air on the mitad's bottom side. An average temperature of averaged 185 °C at the center and 170 °C away from the center was observed; the size of the cone determines the temperature distribution on the metal surface. The reactor's narrower cone diameter allowed for a greater temperature only in the center and a more variable baked Injera eye appearance. The cone diameter has been reduced to 0.15 m of the mitad diameter to improve the temperature distribution on the mitad surface. The gasifier temperature is 800 °C when the air/fuel ratio is 5.8 kg/kg and the moisture content of the wood is 16%. Gasification is improved by heating the primary air and changing the air-fuel ratio. The findings revealed that pre-heated air is more efficient for gasification and saves money on baking and fuel. Fuel efficiency (0.45) and time savings (0.12) were discovered in the new gasifier. Between gasification temperatures of 650 and 800 °C, an effective Injera baking temperature (170-185 °C) on the mitad surface was attained. Following the tests, the average specific wood fuel consumption (1.414 g/kg), char residue (317 g), and average Injera baking time were calculated. For each test of one baking cycle, this was found at the burning rate capability of both stoves, which is 6 kg/hr. Therefore, the fuel consumption and burning rate of fuel are depending on the amount of airflow rate.

Experimental investigation of air cooler using local palm tree waste.

Middle Saudi Arabia has weather conditions where the temperature is high in summer with low humidity. Conventional air conditioning systems operated by a vapor compression cycle are not economical because of the high electrical power consumption. Therefore, evaporative cooling through evaporative coolers is one of the best and most economical solutions. The present study experimentally investigates the factors affecting the performance of evaporative coolers. Pad materials and airflow rate are the main variables to investigate the evaporative cooler's performance in terms of saturation effectiveness, pressure drop across the pads, and coefficient of performance (COP). Pads material are the local palm tree "Nakheel" waste that are leaflet, leaf base, bulb, and roots. The maximum COP of the cooling system in the case of bulb pad material is 80% more than that of leaflet pad material. The saturation effectiveness of the bulb pad was a maximum which is 61.93% at an airflow of 2.25 m/s, which is more than two times that of the saturation effectiveness of the leaflet pad. The pressure drop across the bulb pad is almost 2.5 times to 9.5 times than that of leaflet pad. Results show that bulb pad performance best, whereas the leaflet pad material has the lowest performance in terms of pressure drop, saturation effectiveness, and COP.

Expiratory Muscle Strength Treatment for Refractory Chronic Cough: A Short-term Single Exercise Program.

OBJECTIVES: Patients with chronic cough are some of the most challenging to treat. This preliminary study is the first to examine the effects of a single exercise muscle strength training program to reduce cough severity in patients who failed other treatments. METHODS: A total of 19 females were included in this study, ranging from age 24 to 80. The maximum phonation time (MPT), laryngeal airway resistance (LAR), maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), Voice Handicap Index-10, (VHI-10) and the Cough Severity Index (CSI) values were obtained pre- and post-treatment. ANOVA two-factor without replication was used to compare values pre- and post-treatment. RESULTS: MIP (Mean of 62.00 to a mean of 78.53) and MEP (Mean of 90.00 to a mean of 112.16) showed significant increase post-treatment. In addition, LAR (Mean of 73.30 to a mean of 60.67) and CSI (Mean of 19.37 to a mean of 15.00) significantly decreased post-treatment. General changes in pre- and post-treatment values were identified with MPT (Mean of 14.89 to a mean of 16.17) and VHI-10 (Mean of 8.00 to a mean of 6.76). A follow-up questionnaire indicated that the majority of patients felt their cough was better after 4 weeks. CONCLUSIONS: Muscle strength training provides a tool to aid in the control of cough for patients who are refractory to medical and other behavioral treatments. Improvement in cough may be associated with a reduction in subglottic pressure and increased air flow resulting in lower laryngeal airway resistance.

Effects of press-in airflow rate and the distance between the pressure duct and the side wall on ventilation dust suppression performance in an excavating tunnel.

The efficiency of mine excavation has been significantly enhanced by continuing improvements in tunneling capabilities; however, this has also resulted in serious environmental pollution and greater safety risks for workers. To ensure safe production, the focus of this study is on the effect of varying the air pressure and the distance between the air pressure cylinder and the side wall settings on dust dispersion behavior and dust control in excavated tunnels. We also investigated temporal-spatial dust diffusion rules in tunnels by combining numerical simulation data with field measurement results. Through further analysis, when the pressure air volume and the exhaust air volume are both equal to 250 m3/min, the dust diffusion distance could be fitted as: [Formula: see text]. When the exhaust air volume is equal to 250 m3/min, dust control effects were improved as the pressure air volume decreased, becoming optimal when the pressure air volume dropped to 150 m3/min. Under these conditions, areas of high dust pollution were contained within 16 m of the cutting face, and the dust diffusion distance satisfied the formula: [Formula: see text]. When the pressure air volume is fixed, the change of the distance between the pressure air cylinder and the side wall has little effect on the dust diffusion. When the distance is 1.5 m, the dust control effect is the best, and the high dust pollution area is controlled within 14 m of the cutting surface. This alleviated dust pollution to a certain degree, thereby enhancing the air quality and ensuring safer production. This study provides a new understanding of the environmentally sustainable development of tunnels and is of great significance for clean production.

Mitigating COVID-19 infection disease transmission in indoor environment using physical barriers.

During the normalized phase of COVID-19, droplets or aerosol particles produced by infected personnel are considered as the potential source of infection with uncertain exposure risk. As such, in densely populated open spaces, it is necessary to adopt strategies to mitigate the risk of infection disease transmission while providing sufficient ventilation air. An example of such strategies is use of physical barriers. In this study, the impact of barrier heights on the spread of aerosol particles is investigated in an open office environment with the well-designed ventilation mode and supply air rate. The risk of infection disease transmission is evaluated using simulation of particle concentration in different locations and subject to a number of source scenarios. It was found that a barrier height of at least 60 cm above the desk surface is needed to effectively prevent the transmission of viruses. For workstations within 4 m from the outlet, a 70 cm height is considered, and with a proper ventilation mode, it is shown that the barriers can reduce the risk of infection by 72%. However, for the workstations further away from the outlet (beyond 4 m), the effect of physical barrier cannot be that significant. In summary, this study provides a theoretical analysis for implementing physical barriers, as a low-cost mitigation strategy, subject to various height scenarios and investigation of their effectiveness in reducing the infection transmission probability.

A Comparison of the s/z Ratio to Instrumental Aerodynamic Measures of Phonation.

OBJECTIVE: The purpose of this study was to examine how the s/z ratio and instrumental measures of laryngeal valving and voicing efficiency. STUDY DESIGN: Prospective, cohort design. METHODS: Fifteen adult males (mean age 28.3 years) and 15 adult females (mean age 29.2 years) with normal voice quality were recruited and compared on productions of the s/z ratio and instrumental aerodynamic measures. The aerodynamic measures included vital capacity, maximum phonation time, airflow rate during sustained and sentence production, subglottal pressure, and laryngeal airway resistance. These measures were obtained on the Phonatory Aerodynamic System Model 6600. Statistical analyses included a univariate analysis of variance to examine for differences between sexes for all the variables, and between the s/z ratios for each of the three trials. Pearson's Product Moment Correlations were performed to identify the strength and nature of any significant relationships between the s/z ratio and instrumental aerodynamics. RESULTS: There were significant differences in the mean values between males and females only for the measures of vital capacity and maximum phonation time. There were no significant differences between the three trials for the s/z ratio. There was a significant moderate negative correlation between the s/z ratio and laryngeal airway resistance in females and between the s/z ratio and sentence airflow rate in males. CONCLUSIONS: The s/z ratio demonstrated only a moderate correlation with limited instrumental measures of laryngeal valving. In the absence of clear evidence of its ability to accurately assess laryngeal valving, the s/z ratio should be used in combination with other instrumental measures of laryngeal aerodynamics for a better representation of aerodynamic functioning.

Aerodynamic Characteristics of Syllable and Sentence Productions in Normal Speakers.

BACKGROUND: Aerodynamic measures of subglottic air pressure (Ps) and airflow rate (AFR) are used to select behavioral voice therapy versus surgical treatment for voice disorders. However, these measures are usually taken during a series of syllables, which differs from conversational speech. Repeated syllables do not share the variation found in even simple sentences, and patients may use their best rather than typical voice unless specifically instructed otherwise. This study examined the potential differences in estimated Ps and AFR in syllable and sentence production and their effects on a measure of vocal efficiency in normal speakers. METHODS: Prospective study. Measures of estimated Ps, AFR, and aerodynamic vocal efficiency (AVE) were obtained from 19 female and four male speakers ages 22-44 years with no history of voice disorders. Subjects repeated a series of /pa/ syllables and a sentence at comfortable effort level into a face mask with a pressure-sensing tube between the lips. RESULTS: AVE varies as a function of the speech material in normal subjects. Ps measures were significantly higher for the sentence-production samples than for the syllable-production samples. AFR was higher during sentence production than syllable production, but the difference was not statistically significant. AVE values were significantly higher for syllable versus sentence productions. CONCLUSIONS: The results suggest that subjects increase Ps and AFR in sentence compared with syllable production. Speaking task is a critical factor when considering measures of AVE, and this preliminary study provides a basis for further aerodynamic studies of patient populations.

Toward a new method to classify the airblast sprayers according to their potential drift reduction: comparison of direct and new indirect measurement methods.

BACKGROUND: Drift is one of the most important issues to consider for realising sustainable pesticide sprays. This study proposes an alternative indirect methodology for comparative measurements of drift reduction potential (DRP) generated by airblast sprayers, aimed at overcoming the practical inconveniences and drawbacks of standardized ISO 22866:2005. A test bench in the absence of target crop and wind was employed to measure drift potential values (DPVs). A variation to the proposed method that introduced a crop between sprayer and test bench device was considered to study the canopy effect (absence/presence) and to validate the method. In parallel, direct spray drift measurements (ISO 22866) were performed to obtain the drift value (DV). A representative vineyard airblast sprayer was evaluated in four configurations (a combination of two fan airflow rates and two nozzle types). The configurations tested under the three methods (direct and indirects) were classified according to achieved drift reduction percentages (ISO 22369-1:2013) and compared. RESULTS: Indirect methods discriminated DPVs from different nozzles (conventional, air induction) and fan airflow rate (high, low) combinations. Indirect methods also showed that despite crop influence on drift amount, target absence has a negligible effect when used specifically for DRP determination/classification. In fact, identical DRP final classifications were achieved for the two methodologies tested. Alternatively, all tested configurations resulted in lower DR values following the ISO 22866 field method, which caused different final classifications due to the high dependence of results on external factors. CONCLUSIONS: The alternative test bench methodology, characterized by the absence of target crop and calm of wind, was considered feasible for comparative measurements of airblast sprayer DRP. © 2019 Society of Chemical Industry.

Perception and Respiratory Responses of the Upper Airway Mechanism to Added Resistance With Aging.

Objectives: To assess breathing behaviors and perception of added respiratory loads in young compared to old individuals, and to determine whether aging affects the perception and response to changes in nasal airway resistance. Study design: In a clinical study, 40 young (11-20 years) and 40 older (59-82 years) subjects were evaluated during rest breathing and during the application of added airway resistance loads. Methods: The pressure-flow technique was used to measure airflow rate (mL/s) and oral-nasal pressures (cmH2O) to calculate nasal resistance (cmH2O/L/s). To create calibrated resistance loads for the test conditions, we used a device modified from a precision iris diaphragm. Results: During rest breathing airflow rate was significantly lower for the younger group compared to older group. Using the loading device, 11-20-year-olds detected increased resistance at the level of 2.26 cmH2O/L/s compared to 4.55 cmH2O/L/s in 59-82-year-olds. In contrast to the younger group, mean airflow rate was higher during expiration than during inspiration among 59-82-year-olds except at rest breathing. Conclusions: The data revealed that the perception and respiratory response to increased airway resistance changed with aging. Younger subjects were more sensitive to changes within the airway. In both groups, subjects responded to increased airway resistance by decreasing airflow rate. However, expiratory phase became more active than inspiratory phase only in the older group. Level of Evidence: N/A.

Realistic glottal motion and airflow rate during human breathing.

The glottal geometry is a key factor in the aerosol delivery efficiency for treatment of lung diseases. However, while glottal vibrations were extensively studied during human phonation, the realistic glottal motion during breathing is poorly understood. Therefore, most current studies assume an idealized steady glottis in the context of respiratory dynamics, and thus neglect the flow unsteadiness related to this motion. This is particularly important to assess the aerosol transport mechanisms in upper airways. This article presents a clinical study conducted on 20 volunteers, to examine the realistic glottal motion during several breathing tasks. Nasofibroscopy was used to investigate the glottal geometrical variations simultaneously with accurate airflow rate measurements. In total, 144 breathing sequences of 30s were recorded. Regarding the whole database, two cases of glottal time-variations were found: "static" or "dynamic" ones. Typically, the peak value of glottal area during slow breathing narrowed from 217 ± 54 mm(2) (mean ± STD) during inspiration, to 178 ± 35 mm(2) during expiration. Considering flow unsteadiness, it is shown that the harmonic approximation of the airflow rate underevaluates the inertial effects as compared to realistic patterns, especially at the onset of the breathing cycle. These measurements provide input data to conduct realistic numerical simulations of laryngeal airflow and particle deposition.

An Aerodynamic Study of Phonations in Patients With Parkinson Disease (PD).

BACKGROUND: The precise comparison of the voice characteristics of Parkinson disease (PD) patients with age-matched normal subjects is still one of the important research projects. The present study aimed at comparing the voice characteristics in sustained phonations of PD patients with an age-matched control group. METHODS: The subjects were 30 Japanese PD patients (15 males and 15 females). The control group consisted of 30 age-matched normal Japanese subjects (15 males and 15 females). Each subject was required to phonate into a mouthpiece attached to Vocal Function Analyzer (PS-77E; Nagashima Medical Instrumental Corporation, Tokyo, Japan) with the airway interruption system, and expiratory lung pressure, mean flow rate, fundamental frequency and intensity of voice, and pitch range were measured. Maximum phonation time was also assessed. RESULTS: The highest pitch level was significantly lower in the PD group than that of the control group in both sexes, whereas the lowest pitch level was significantly higher in the PD group only in males. In both sexes, the pitch range was significantly narrower in the PD group than in the control group. There was no significant difference in intensity, mean flow rate, expiratory pressure, or maximum phonation time between the two groups, for both males and females. CONCLUSION: Only remarkable difference in the voice characteristics between PD patients and age-matched normal elderlies was limited to the narrowing of the pitch range in PD patients. The restriction in pitch regulation in PD patients was considered to be because of difficulty in reciprocal control of the laryngeal muscles secondary to latent rigidity.

Airflow-induced triboelectric nanogenerator as a self-powered sensor for detecting humidity and airflow rate.

Humidity sensors are commonly based on the resistance change of metal oxide semiconductors, which show high sensitivity in low humidity but low sensitivity in high humidity. In this work, we design a novel humidity sensor based on the airflow-induced triboelectric nanogenerator (ATNG) that can serve as a self-powered sensor to detect humidity (especially in high humidity) and airflow rate. The output current or voltage change is investigated under different humidity (20-100% relative humidity) at fixed airflow rate and different airflow rates (15-25 L/min) at a fixed humidity. The working principle of the ATNG-based sensor is illustrated. We find that both output current and voltage can serve as a variable for detecting humidity, while only the output current can serve as a variable for determining airflow rate. Our study demonstrates an innovative approach toward detection of humidity and airflow rate with advantages of self-power, multifunction, low cost, simple fabrication, and high sensitivity.