measurement methodology
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Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 314
Author(s):  
Krzysztof Nering ◽  
Alicja Kowalska-Koczwara

This paper is aimed at investigating the use of polyurethane mats, usually used as ballast mats, for residential building purposes. Ballast mats have features that may improve the vibroacoustic comfort in residential rooms. Their strength is certainly an advantage, along with vibration and acoustic insulation. However, the problem that an engineer has to deal with, for example in modeling these types of mats, is a limited knowledge of the material’s vibroacoustic parameters. Knowledge of these may be useful for residential buildings. This paper presents measurements of the vibroacoustic parameters of polyurethane mats, together with a suitable methodology and some results and analysis. The two main material parameters responsible for vibroacoustic protection were measured: the dynamic stiffness, which is related to the acoustic properties of the material, and the critical damping coefficient, which is obviously responsible for damping. The measurement methodology is clearly described. A total of five polyurethane materials with different densities were tested. It was possible to identify a relationship between the material density and the vibroacoustic parameters, which could offer an indication of which material to use, depending on the stimulus affecting a human in a given location.


2021 ◽  
Vol 11 (24) ◽  
pp. 12139
Author(s):  
Monica Lilioara Cherecheș ◽  
Nelu Cristian Cherecheș ◽  
Adrian Alexandru Ciobanu ◽  
Sebastian Valeriu Hudișteanu ◽  
Emilian Florin Țurcanu ◽  
...  

In the context of energy conservation and sustainable development, building design should take into account the energy efficiency criteria by using renewable energy sources. Double-skin facades (DSF) represent innovative energy-efficient techniques that have gained increasing interest worldwide. The present study reports the results of an experimental campaign performed on a full-scale double-skin façade using the in-situ measurement methodology. The thermodynamic behavior of the façade is studied under real exterior climatic conditions in Romania in hot and cold seasons, and performance indicators in terms of pre-heating efficiency and dynamic insulation efficiency were determined. Three summer periods are analyzed corresponding to the outdoor air curtain scenario for three ventilation modes in naturally or mechanically ventilated single-story DSF. Results revealed that the third ventilation scenario, which combines horizontal and vertical openings, gives the best efficiency of 71.3% in the double skin façade functioning. During the cold season, the channel façade behaved like a thermal buffer between the building and the exterior air, ensuring the thermal energy for partial or integral heating of the building.


2021 ◽  
Vol 11 (6) ◽  
pp. 7750-7756
Author(s):  
N. B. Serradj ◽  
A. D. K. Ali ◽  
M. E. A. Ghernaout

In this study, an experimental measurement methodology is implemented that allows obtaining consistent temperature data during the turning operation of semi-hard C20 steel using SNMG carbide insert, allowing us to have better control at the tool-part interface. The interactions of the phenomena influencing the cut led our choices on the development of a correlation model for the analysis and prediction of the relationships between the machining parameters by measurement of the temperature. The measurement procedure implemented for the temperature estimate is based on the use of an FLIR A325sc type infrared camera mounted and protected by a device on the machine tool. The Taguchi method was chosen to find the relationships between the input factors (cutting speed (Vc), feed rate (a), depth of cut (p)), and the output factor (temperature (T)). In the future, we will develop a numerical validation model to simulate the machining process in order to predict temperatures


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7492
Author(s):  
Jung-Youl Choi ◽  
Sun-Hee Kim ◽  
Ho-Hyun Lee ◽  
Jee-Seung Chung

This study evaluated the structural stability of subway structures based on adjacent excavations by comparing automatically measured and numerically analyzed data. The reliability of the automated measurement methodology was evaluated by first applying probability statistical analysis to the measured results and then comparing these results with the numerically analyzed results. An improvement in the calculation method evaluation system, including the method of processing and analysis of the automatically measured data of subway structures through the average value of probability density, was proposed. As a result of the field measurement and numerical analysis, the measured results of tunnel displacement and track deformation exhibited some differences. However, it was determined that the construction stage and location where the maximum values of the tunnel displacement and track deformation occurred had similarities.


Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8147
Author(s):  
Ionuț Vasile ◽  
Emil Tudor ◽  
Ion-Cătălin Sburlan ◽  
Marius-Alin Gheți ◽  
Gabriel Popa

LiDAR sensors are needed for use in vehicular applications, particularly due to their good behavior in low-light environments, as they represent a possible solution for the safety systems of vehicles that have a long braking distance, such as trams. The testing of long-range LiDAR dynamic responses is very important for vehicle applications because of the presence of difficult operation conditions, such as different weather conditions or fake targets between the sensor and the tracked vehicle. The goal of the authors in this paper was to develop an experimental model for indoor testing, using a scaled vehicle that can measure the distances and the speeds relative to a fixed or a moving obstacle. This model, containing a LiDAR sensor, was developed to operate at variable speeds, at which the software functions were validated by repeated tests. Once the software procedures are validated, they can be applied on the full-scale model. The findings of this research include the validation of the frontal distance and relative speed measurement methodology, in addition to the validation of the independence of the measurements to the color of the obstacle and to the ambient light.


2021 ◽  
Vol 8 ◽  
Author(s):  
Rui Xie ◽  
Bingjie Qiu ◽  
Jay Chhablani ◽  
Xinyuan Zhang

The choroid is the main source of blood and nourishment supply to the eye. The dysfunction of the choroid has been implicated in various retinal and choroidal diseases. The identification and in-depth understanding of pachychoroid spectrum disorders are based on the tremendous progress of optical coherence tomography (OCT) technology in recent years, although visibility of choroid is challenging in the era of the time or spectral domain OCT. The recent rapid revolution of OCTs, such as the enhanced depth imaging OCT and the swept-source OCT, has greatly contributed to the significant improvement in the analysis of the morphology and physiology of the choroid precisely, especially to the choroid–scleral boundary and vasculature. The present review highlights the recently available evidence on the measurement methodology and the clinical significance of choroidal thickness in retinal or choroidal disorders.


2021 ◽  
Author(s):  
Cathy A Speed ◽  
Tom Arneil ◽  
Robert K Harle ◽  
Alex Wilson ◽  
Alan Karthikesalingam ◽  
...  

Background: Photoplethysmography (PPG) sensors, typically found in wrist-worn devices, can continuously monitor heart rate (HR) in large populations in real-world settings. Resting heart rate (RHR) is an important biomarker of morbidities and mortality, but no universally accepted definition nor measurement criteria exist. In this study, we provide a working definition of RHR and describe a method for measurement of RHR recorded using PPG derived from wristband measurement across a 24-hour cycle. Methods: 433 healthy subjects wore a wrist device that measured activity and HR for up to 3 months. HR during inactivity was recorded and the duration of inactivity needed for HR to stabilise was ascertained. We identified the lowest HR during each 24-hour cycle (true RHR) and examined the time of day or night this occurred. The variation of HR during inactivity through the 24-hour cycle was also assessed. The sample was also subdivided according to daily activity levels for subset analysis. Findings: Adequate data was obtained for 19,242 days and 18,520 nights. HR stabilised in most subjects after 4 minutes of inactivity. Mean (SD) RHR for the sample was 54.5 (8.0) bpm (day) and 50.5 (7.6) bpm (night). RHR values were highest in the least active group (lowest MET quartile) . A circadian variation of HR during inactivity was confirmed, with the lowest values being between 0300 and 0700 hours for most subjects. Interpretation: RHR measured using a PPG-based wrist-worn device is significantly lower at night than in the day, and a circadian rhythm of HR during inactivity was confirmed. Since RHR is such an important health metric, clarity on the definition and measurement methodology used is important. A minimum rest time of 4 minutes provides a reliable measurement of HR during inactivity and true RHR in a 24-hour cycle is best measured between 0300 and 0700 hours. Funding: This study was funded by Google.


2021 ◽  
Vol 2094 (5) ◽  
pp. 052031
Author(s):  
A K Miraliyeva ◽  
A S Rashidov ◽  
Z X Ernazarova ◽  
Sh M Masharipov ◽  
G M Mirpayziyeva

Abstract If the measurement produces a numerical result (or the stated result is based on a numerical result), then it is necessary to evaluate the uncertainty of these numerical results. If the test methodology does not provide for a rigorous, metrologically and statistically reliable estimate of measurement uncertainty, the test laboratory should attempt to reasonably assess the uncertainty of the measurement results. This is applicable in the case of test methods both rational and empirical. As well as in the laboratory activities, verification of test methods plays an important role in order to guarantee the competence of the laboratory by checking for the criteria of Kohren, Grabbs and others. In cases where test results are not numerically expressed or based on numerical data (e.g., fit/unsuitable or positive/negative, or based on visual or sensory perceptions or other forms of quality analysis), estimates of uncertainty or other variability of results are not required. Nevertheless, laboratories are advised to have an idea of the variability of the results, if possible. The importance of the uncertainty of qualitative test results is undeniable, as is the fact that the necessary statistical methodology (procedure) exists for the calculations. However, due to the complexity of the issue and the inconsistency in the approaches, it is not currently necessary for laboratories to assess the uncertainty of qualitative test results. However, this issue needs to be considered. The article discusses estimates of uncertainty of analytical measurements taking into account the requirements of regulatory documents. The criteria for verification of measurement methodology based on experimental works are also considered and analyzed.


2021 ◽  
Vol 91 (3) ◽  
pp. 102-113
Author(s):  
M. P. Shatenok ◽  
A. N. Moiseev ◽  
K. V. Tolkachev ◽  
S. A. Ryghov ◽  
Yu. V. Drughinina ◽  
...  

The CDT guidelines on external dosimetry audit of linear accelerators x-ray beams absolute calibration is described. The guidelines specify audits organization, conduction and results analysis for 4-20 MeV photon beams, including measurement methodology, equipment and staff specification. The guidelines are designed for medical physicists, dosimetrists and management of external beam radiotherapy departments.


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