Ergonomic evaluation of low-cost intervention for carpet trimming workers exposed to hand vibration and noise

2019 ◽  
Vol 50 (3) ◽  
pp. 78-91 ◽  
Author(s):  
Ashish Kumar Singh ◽  
Makkhan Lal Meena ◽  
Himanshu Chaudhary
Keyword(s):  
Root Mean Square ◽  
Noise Exposure ◽  
Low Cost ◽  
Hearing Threshold ◽  
Subjective Perception ◽  
Mean Square ◽  
Frequency Range ◽  
Noise Levels ◽  
Practical Applications ◽  
Positive Effect

The aim of the study was to investigate the occupational use of low-cost intervention for carpet trimming occupation. This study quantifies the effect of hand-arm vibration and noise exposure to loss in hearing threshold among trimming workers. Ten male participants (right handed) involved in carpet trimming volunteered to participate in this interventional experiment. The participants were queried about the usability of prototype handle based on their subjective perception evaluated through the use of scoresheet/questionnaire. Results demonstrated that the handle intervention reduced the total value of root mean square frequency-weighted vibrations by more than 40% when compared with the conventional handle. The workers were exposed to noise levels ranging from 87.2 to 91.8 dB(A) (mean 89.55 dB(A)). They exhibit mild-to-moderate hearing impairment in the frequency range of 3000–6000 Hz. Based on this preliminary work, we have found that prototype handle was effective in curtailing hand-arm vibration. The prototype handle showed a positive effect on the usability ratings. More practical applications should be explored to prevail the combined effect of hand-arm vibration and noise.

scholarly journals Low Cost Automatic Reconstruction of Tree Structure by AdQSM with Terrestrial Close-Range Photogrammetry

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1020
Author(s):  
Yanqi Dong ◽  
Guangpeng Fan ◽  
Zhiwu Zhou ◽  
Jincheng Liu ◽  
Yongguo Wang ◽  
...  
Keyword(s):  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Low Cost ◽  
Reference Value ◽  
Tree Height ◽  
Point Clouds ◽  
Tree Structure ◽  
Mean Square ◽  
Tree Model

The quantitative structure model (QSM) contains the branch geometry and attributes of the tree. AdQSM is a new, accurate, and detailed tree QSM. In this paper, an automatic modeling method based on AdQSM is developed, and a low-cost technical scheme of tree structure modeling is provided, so that AdQSM can be freely used by more people. First, we used two digital cameras to collect two-dimensional (2D) photos of trees and generated three-dimensional (3D) point clouds of plot and segmented individual tree from the plot point clouds. Then a new QSM-AdQSM was used to construct tree model from point clouds of 44 trees. Finally, to verify the effectiveness of our method, the diameter at breast height (DBH), tree height, and trunk volume were derived from the reconstructed tree model. These parameters extracted from AdQSM were compared with the reference values from forest inventory. For the DBH, the relative bias (rBias), root mean square error (RMSE), and coefficient of variation of root mean square error (rRMSE) were 4.26%, 1.93 cm, and 6.60%. For the tree height, the rBias, RMSE, and rRMSE were—10.86%, 1.67 m, and 12.34%. The determination coefficient (R2) of DBH and tree height estimated by AdQSM and the reference value were 0.94 and 0.86. We used the trunk volume calculated by the allometric equation as a reference value to test the accuracy of AdQSM. The trunk volume was estimated based on AdQSM, and its bias was 0.07066 m3, rBias was 18.73%, RMSE was 0.12369 m3, rRMSE was 32.78%. To better evaluate the accuracy of QSM’s reconstruction of the trunk volume, we compared AdQSM and TreeQSM in the same dataset. The bias of the trunk volume estimated based on TreeQSM was −0.05071 m3, and the rBias was −13.44%, RMSE was 0.13267 m3, rRMSE was 35.16%. At 95% confidence interval level, the concordance correlation coefficient (CCC = 0.77) of the agreement between the estimated tree trunk volume of AdQSM and the reference value was greater than that of TreeQSM (CCC = 0.60). The significance of this research is as follows: (1) The automatic modeling method based on AdQSM is developed, which expands the application scope of AdQSM; (2) provide low-cost photogrammetric point cloud as the input data of AdQSM; (3) explore the potential of AdQSM to reconstruct forest terrestrial photogrammetric point clouds.

Back-iron design-based electromagnetic regenerative tuned mass damper

2020 ◽  
Vol 234 (3) ◽  
pp. 607-622
Author(s):  
Semen Kopylov ◽  
Zhaobo Chen ◽  
Mohamed AA Abdelkareem
Keyword(s):  
Root Mean Square ◽  
Tuned Mass Damper ◽  
Harmonic Excitation ◽  
Experimental Results ◽  
Mean Square ◽  
Tuned Mass Dampers ◽  
Practical Applications ◽  
Mass Damper ◽  
Compact Dimension ◽  
Regenerative Power

Implementation of tuned mass dampers is the commonly used approach to avoid excessive vibrations in civil engineering. However, due to the absence of the compact dimension, there are still no practical applications of the tuned mass dampers in automotive industry. Meanwhile, recent investigations showed the benefit of utilizing a tuned mass damper in a vehicle suspension in terms of driving comfort and road holding. Thus, the current investigation aimed to explore a novel compact dimension tuned mass damper, which can provide both sufficient vibration mitigation and energy harvesting. This paper presents a prototype of a back-iron-based design of an electromagnetic regenerative tuned mass damper. The mathematical model of the tuned mass damper system was developed and has been validated by the experimental results of the tuned mass damper prototype implemented in a protected mass test-bench. The indicated results concluded that the attenuation performance dramatically deteriorated under random excitations and a reduction in the root-mean-square acceleration of 18% is concluded compared to the case with undamped tuned mass damper. Under harmonic excitations, the designed tuned mass damper prototype is able to reduce the peak acceleration value of the protected structure by 79%. According to the experimental results, the designed tuned mass damper prototype revealed a peak regenerative power of 0.76 W under a harmonic excitation of 8.1 Hz frequency [Formula: see text]m amplitude. Given the simulated random road profiles from C to E, the back-iron electromagnetic tuned mass damper indicated that root-mean-square harvested power from 0.6 to 6.4 W, respectively.

scholarly journals Manufacture of Highly Transparent and Hazy Cellulose Nanofibril Films via Coating TEMPO-Oxidized Wood Fibers

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 107 ◽  
Author(s):  
Weisheng Yang ◽  
Liang Jiao ◽  
Wei Liu ◽  
Hongqi Dai
Keyword(s):  
Root Mean Square ◽  
Low Cost ◽  
Inorganic Nanoparticles ◽  
Root Mean Square Roughness ◽  
Mean Square ◽  
Cellulose Nanofibril ◽  
Wood Fibers ◽  
Excellent Thermal Stability ◽  
Blending Method ◽  
Coating Method

Traditionally, inorganic nanoparticles (SiO2, TiO2) have been utilized to tune the optical haze of optoelectronic devices. However, restricted to complex and costly processes for incorporating these nanoparticles, a simple and low-cost approach becomes particularly important. In this work, a simple, effective, and low-cost method was proposed to improve optical haze of transparent cellulose nanofibril films by directly depositing micro-sized 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized wood fibers (“coating” method). The obtained films had a high total transmittance of 85% and a high haze of 62%. The film samples also showed a high tensile strength of 80 MPa and excellent thermal stability. Dual sides of the obtained films had different microstructures: one side was extremely smooth (root-mean-square roughness of 6.25 nm), and the other was extremely rough (root-mean-square roughness of 918 nm). As a reference, micro-sized TEMPO-oxidized wood fibers and cellulose nanofibrils were mixed to form a transparent and hazy film (“blending” method). These results show that hazy transparent films prepared using the “coating” method exhibit superior application performances than films prepared using the “blending” method.

Physiological action tremor of the ankle

1982 ◽  
Vol 52 (1) ◽  
pp. 226-230 ◽  
Author(s):  
R. S. Pozos ◽  
P. A. Iaizzo ◽  
R. W. Petry
Keyword(s):  
Root Mean Square ◽  
Frequency Analysis ◽  
Tibialis Anterior ◽  
Voluntary Movement ◽  
Physiological Tremor ◽  
Mean Square ◽  
Frequency Range ◽  
Action Tremor ◽  
Spectral Techniques ◽  
Physiological Action

Comparisons were made between physiological tremor (PT), which is the involuntary oscillation produced when the leg is held in a plantarflexed position, and physiological action tremor (PAT), which is an involuntary oscillation associated with the voluntary slow raising and lowering of the heel. Frequency analysis using spectral techniques revealed a major frequency range of 6–9 Hz for PT and a major frequency range of 4–8 Hz for PAT. Computed root-mean-square (rms) acceleration values for each tremor type showed that the amplitude of PAT was significantly higher (2–5 times) than that of PT. This significant increase in amplitude occurred at specific stages of the voluntary movement. Major peaks in the spectral plots of the demodulated electromyogram signals of the soleus and tibialis anterior muscles corresponded to the frequency peaks seen with PAT.

Quantitatively Characterizing Damages on Steel Beams by Using PZT Impedance Method

2011 ◽  
Vol 675-677 ◽  
pp. 1135-1138
Author(s):  
Hai Yan Qiao ◽  
Ji Cheng Li ◽  
Li Lin ◽  
Xi Meng Li
Keyword(s):  
Root Mean Square ◽  
Root Mean Square Deviation ◽  
Impedance Spectrum ◽  
Initial Crack ◽  
Impedance Method ◽  
Steel Beams ◽  
Steel Beam ◽  
Mean Square ◽  
Mean Square Deviation ◽  
Frequency Range

The PZT-based electro-mechanical (E/M) method was utilized to measure the impedance of a 1-D steel beam with cracks introducing and developing. Quantitatively assessment of cracks was made by using damage metrics Root Mean Square Deviation (RMSD) and Covariance (Cov). Changes in the coupled impedance of PZT and the beam (500mm×20mm×6mm) were investigated during the appearance and extension of cracks. With the depth of crack dc increasing from 0.6mm to 1.8mm, the peaks of impedance spectrum shifted to lower frequency in the frequency range of 182 kHz-370 kHz and the amplitude showed a decreasing tendency. Moreover, the initial crack brought more significant changes in impedance than that from the developing of cracks. The relationships between dc and RMSD/Cov were investigated. It was proved that RMSD and Cov were efficient in quantitatively presenting the extension of cracks on the 1-D beam.

Evaluation of a Low-Cost Pneumatic Plantar Pressure Insole for Predicting Ground Contact Kinetics

2016 ◽  
Vol 32 (2) ◽  
pp. 215-220 ◽  
Author(s):  
Daniel A. Jacobs ◽  
Daniel P. Ferris
Keyword(s):  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Plantar Pressure ◽  
Center Of Pressure ◽  
Low Cost ◽  
Position Vector ◽  
Mean Square ◽  
Torque Vector ◽  
Sit To Stand

Instrumented insoles could benefit locomotion research on healthy and clinical populations by providing data in natural settings outside of the laboratory. We designed a low-cost, instrumented insole with 8 pneumatic bladders to measure localized plantar pressure information. We collected gait data during treadmill walking at 1.0 m/s and 1.5 m/s and for sit-to-stand and stand-tosit tasks for 10 subjects. We estimated a common representation of ground kinetics (3-component force vector, 2-component center of pressure position vector, and a single-component torque vector) from the insole data. We trained an intertask neural network for each component of the kinetic data. For the walking tasks at 1.0 m/s and 1.5 m/s, the normalized root mean square error was between 3.1% and 12.9% and for the sit-to-stand and stand-to-sit tasks, the normalized root mean square error was between 3.3% and 21.3% Our findings suggest that the proposed low-cost, instrumented insoles could provide useful data about movement kinetics during real-world activities.

scholarly journals Evaluation methods for low-cost particulate matter sensors

2021 ◽  
Author(s):  
Jeffrey K. Bean
Keyword(s):  
Quality Assurance ◽  
Particulate Matter ◽  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Prediction Interval ◽  
Low Cost ◽  
Sensor Data ◽  
Rural Site ◽  
Mean Square

Abstract. Understanding and improving the quality of data generated from low-cost sensors is a crucial step in using these sensors to fill gaps in air quality measurement and understanding. This paper shows results from a 10-month long campaign that included side-by-side measurements and comparison between EPA-approved reference instruments and low-cost particulate matter sensors in Bartlesville, Oklahoma. At this rural site in the Midwestern United States the instruments typically encountered only low (under 20 µg/m3) concentrations of particulate matter, however higher concentrations (50–400 µg/m3) were observed on three different days during what were likely agricultural burning events. This study focused on methods for understanding and improving data quality for low-cost particulate matter sensors. The data offered insights on how averaging time, choice of reference instrument, and the observation of higher pollutant concentrations can all impact performance indicators (R2 and root mean square error) for an evaluation. The influence of these factors should be considered when comparing one sensor to another or when determining whether a sensor can produce data that fits a specific need. Though R2 and root mean square error remain the dominant metrics in sensor evaluations, an alternative approach using a prediction interval may offer more consistency between evaluations and a more direct interpretation of sensor data following an evaluation. Ongoing quality assurance for sensor data is needed to ensure data continues to meet expectations. Observations of trends in linear regression parameters and sensor bias were used to analyze calibration and other quality assurance techniques.

Shielded open-circuited probe for in-situ measurements of soil permittivity in Very high frequency (VHF) and Ultra high frequency (UHF) bands

2021 ◽  
pp. 014233122110377
Author(s):  
Konstantin Muzalevskiy ◽  
Andrey Karavaysky
Keyword(s):  
Reflection Coefficient ◽  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
High Frequency ◽  
Mean Square ◽  
Frequency Range ◽  
Frequency Spectra ◽  
Determination Coefficient ◽  
Error Determination

In this paper, the shielded open-circuited probe operating in the wide frequency range from 75MHz to 2GHz is proposed. The probe is made of an SubMiniature version A (SMA) flange connector. The central rod of the SMA connector emerges from a coaxial transition in the flange and shielded by four rods. The robe design allows us to calculate of the probe reflection coefficient S11 used simple analytical transmission line model (TEM wave mode), the parameters of which were calibrated on a set of substances with a known frequency spectrum of permittivity. The refractive index (RI) and normalized attenuation coefficient (NAC) retrieval technique is based on solving the inverse problem of minimizing the residual norm between measured and calculated frequency spectra of reflection coefficient S11. After calibration, the root-mean-square error (determination coefficient) between the measured and calculated module and phase of the reflection coefficient S11 for the sets of calibration media air, distilled water, butanol, pure ice, water solution with NaCl of salinity of 8.9% do not exceed 0.26dB (0.995) and 0.03 rad (0.999), respectively, in the frequency range from 75MHz to 2GHz. The root-mean-square error (determination coefficient) between the measured RI and NAC spectra for four soil cover samples (variation of the clay fraction from 10.5 g/g to 47.6 g/g) using the proposed probe and a precision coaxial cell not exceeds 0.109 (0.993) and 0.057 (0.986), respectively, in the frequency range from 75 MHz to 2 GHz. As a result, it is experimentally shown that RI и NAC can be measured by the proposed non-precision probe with an error comparable to the precision coaxial cell.

scholarly journals Evaluation methods for low-cost particulate matter sensors

2021 ◽  
Vol 14 (11) ◽  
pp. 7369-7379
Author(s):  
Jeffrey K. Bean
Keyword(s):  
United States ◽  
Quality Assurance ◽  
Particulate Matter ◽  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Low Cost ◽  
Sensor Data ◽  
Rural Site ◽  
Mean Square

Abstract. Understanding and improving the quality of data generated from low-cost sensors represent a crucial step in using these sensors to fill gaps in air quality measurement and understanding. This paper shows results from a 10-month-long campaign that included side-by-side measurements and comparison between reference instruments approved by the United States Environmental Protection Agency (EPA) and low-cost particulate matter sensors in Bartlesville, Oklahoma. At this rural site in the Midwestern United States the instruments typically encountered only low (under 20 µg m−3) concentrations of particulate matter; however, higher concentrations (50–400 µg m−3) were observed on 3 different days during what were likely agricultural burning events. This study focused on methods for understanding and improving data quality for low-cost particulate matter sensors. The data offered insights on how averaging time, choice of reference instrument, and the observation of higher pollutant concentrations can all impact performance indicators (R2 and root mean square error) for an evaluation. The influence of these factors should be considered when comparing one sensor to another or when determining whether a sensor can produce data that fit a specific need. Though R2 and root mean square error remain the dominant metrics in sensor evaluations, an alternative approach using a prediction interval may offer more consistency between evaluations and a more direct interpretation of sensor data following an evaluation. Ongoing quality assurance for sensor data is needed to ensure that data continue to meet expectations. Observations of trends in linear regression parameters and sensor bias were used to analyze calibration and other quality assurance techniques.

scholarly journals Mapping Topobathymetry in a Shallow Tidal Environment Using Low-Cost Technology

2020 ◽  
Vol 12 (9) ◽  
pp. 1394 ◽  
Author(s):  
Sibila A. Genchi ◽  
Alejandro J. Vitale ◽  
Gerardo M. E. Perillo ◽  
Carina Seitz ◽  
Claudio A. Delrieux
Keyword(s):  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Low Cost ◽  
Vertical Plane ◽  
Detailed Knowledge ◽  
Mean Square ◽  
Bahía Blanca Estuary ◽  
Weighting Method ◽  
Data Source

Detailed knowledge of nearshore topography and bathymetry is required for a wide variety of purposes, including ecosystem protection, coastal management, and flood and erosion monitoring and research, among others. Both topography and bathymetry are usually studied separately; however, many scientific questions and challenges require an integrated approach. LiDAR technology is often the preferred data source for the generation of topobathymetric models, but because of its high cost, it is necessary to exploit other data sources. In this regard, the main goal of this study was to present a methodological proposal to generate a topobathymetric model, using low-cost unmanned platforms (unmanned aerial vehicle and unmanned surface vessel) in a very shallow/shallow and turbid tidal environment (Bahía Blanca estuary, Argentina). Moreover, a cross-analysis of the topobathymetric and the tide level data was conducted, to provide a classification of hydrogeomorphic zones. As a main result, a continuous terrain model was built, with a spatial resolution of approximately 0.08 m (topography) and 0.50 m (bathymetry). Concerning the structure from motion-derived topography, the accuracy gave a root mean square error of 0.09 m for the vertical plane. The best interpolated bathymetry (inverse distance weighting method), which was aligned to the topography (as reference), showed a root mean square error of 0.18 m (in average) and a mean absolute error of 0.05 m. The final topobathymetric model showed an adequate representation of the terrain, making it well suited for examining many landforms. This study helps to confirm the potential for remote sensing of shallow tidal environments by demonstrating how the data source heterogeneity can be exploited.

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