scholarly journals Effects of Sensor Types and Angular Velocity Computational Methods in Field Measurements of Occupational Upper Arm and Trunk Postures and Movements

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5527
Author(s):  
Xuelong Fan ◽  
Carl Mikael Lind ◽  
Ida-Märta Rhen ◽  
Mikael Forsman
Keyword(s):  
Angular Velocity ◽  
Computational Methods ◽  
Field Measurements ◽  
Field Work ◽  
Field Studies ◽  
Velocity Versus ◽  
Limit Values ◽  
Occupational Setting ◽  
Measurement Units ◽  
Warehouse Workers

Accelerometer-based inclinometers have dominated kinematic measurements in previous field studies, while the use of inertial measurement units that additionally include gyroscopes is rapidly increasing. Recent laboratory studies suggest that these two sensor types and the two commonly used angular velocity computational methods may produce substantially different results. The aim of this study was, therefore, to evaluate the effects of sensor types and angular velocity computational methods on the measures of work postures and movements in a real occupational setting. Half-workday recordings of arm and trunk postures, and movements from 38 warehouse workers were compared using two sensor types: accelerometers versus accelerometers with gyroscopes—and using two angular velocity computational methods, i.e., inclination velocity versus generalized velocity. The results showed an overall small difference (<2° and value independent) for posture percentiles between the two sensor types, but substantial differences in movement percentiles both between the sensor types and between the angular computational methods. For example, the group mean of the 50th percentiles were for accelerometers: 71°/s (generalized velocity) and 33°/s (inclination velocity)—and for accelerometers with gyroscopes: 31°/s (generalized velocity) and 16°/s (inclination velocity). The significant effects of sensor types and angular computational methods on angular velocity measures in field work are important in inter-study comparisons and in comparisons to recommended threshold limit values.

scholarly journals Willows Used for Phytoremediation Increased Organic Contaminant Concentrations in Soil Surface

2021 ◽  
Vol 11 (7) ◽  
pp. 2979
Author(s):  
Maxime Fortin Faubert ◽  
Dominic Desjardins ◽  
Mohamed Hijri ◽  
Michel Labrecque
Keyword(s):  
Soil Surface ◽  
Field Work ◽  
Field Studies ◽  
Soil Hydrology ◽  
Intensive Culture ◽  
Shrub Species ◽  
Short Rotation ◽  
Pollutant Concentrations ◽  
Polycyclic Aromatic ◽  
Made In

The Salix genus includes shrub species that are widely used in phytoremediation and various other phytotechnologies due to their advantageous characteristics, such as a high evapotranspiration (ET) rate, in particular when cultivated in short rotation intensive culture (SRIC). Observations made in past field studies suggest that ET and its impact on soil hydrology can also lead to increases in soil pollutant concentrations near shrubs. To investigate this, sections of a mature willow plantation (seven years old) were cut to eliminate transpiration (Cut treatment). Soil concentrations of polychlorinated biphenyls (PCBs), aliphatic compounds C10–C50, polycyclic aromatic hydrocarbons (PAHs) and five trace elements (Cd, Cr, Cu, Ni and Zn) were compared between the Cut and the uncut plots (Salix miyabeana ‘SX61’). Over 24 months, the results clearly show that removal of the willow shrubs limited the contaminants’ increase in the soil surface, as observed for C10–C50 and of 10 PAHs under the Salix treatment. This finding strongly reinforces a hypothesis that SRIC of willows may facilitate the migration of contaminants towards their roots, thus increasing their concentration in the surrounding soil. Such a “pumping effect” in a high-density willow crop is a prominent characteristic specific to field studies that can lead to counterintuitive results. Although apparent increases of contaminant concentrations contradict the purification benefits usually pursued in phytoremediation, the possibility of active phytoextraction and rhizodegradation is not excluded. Moreover, increases of pollutant concentrations under shrubs following migration suggest that decreases would consequently occur at the source points. Some reflections on interpreting field work results are provided.

scholarly journals Analysis of ergonomic and unergonomic human lifting behaviors by using Inertial Measurement Units

2017 ◽  
Vol 3 (1) ◽  
pp. 7-10 ◽  
Author(s):  
Jan Kuschan ◽  
Henning Schmidt ◽  
Jörg Krüger
Keyword(s):  
Quality Of Life ◽  
Machine Learning ◽  
Angular Velocity ◽  
Musculoskeletal System ◽  
Occupational Diseases ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Measurement Units ◽  
Main Components

Abstract:This paper presents an analysis of two distinct human lifting movements regarding acceleration and angular velocity. For the first movement, the ergonomic one, the test persons produced the lifting power by squatting down, bending at the hips and knees only. Whereas performing the unergonomic one they bent forward lifting the box mainly with their backs. The measurements were taken by using a vest equipped with five Inertial Measurement Units (IMU) with 9 Dimensions of Freedom (DOF) each. In the following the IMU data captured for these two movements will be evaluated using statistics and visualized. It will also be discussed with respect to their suitability as features for further machine learning classifications. The reason for observing these movements is that occupational diseases of the musculoskeletal system lead to a reduction of the workers’ quality of life and extra costs for companies. Therefore, a vest, called CareJack, was designed to give the worker a real-time feedback about his ergonomic state while working. The CareJack is an approach to reduce the risk of spinal and back diseases. This paper will also present the idea behind it as well as its main components.

The Collapse of Thermal Contraction

1999 ◽  
Author(s):  
Naomi Oreskes
Keyword(s):  
Field Work ◽  
Field Studies ◽  
Lower Limbs ◽  
Swiss Alps ◽  
Late Nineteenth Century ◽  
Thermal Contraction ◽  
Thrust Faults ◽  
The Alps ◽  
Academy Of Sciences ◽  
Contraction Theory

In 1901, Karl Zittel, president of the Bavarian Royal Academy of Sciences, declared that “Suess has secured almost general recognition for the contraction theory” of mountain-building. This was wishful thinking. Suess’s Das Antlitz der Erde was indeed an influential work, but by the time Suess finished the final volume (1904), the thermal contraction theory was under serious attack. Problems were evident from three different but equally important quarters. The most obvious problem for contraction theory arose from field studies of mountains themselves. As early as the 1840s, it had been recognized that the Swiss Alps contained large slabs of rock that appeared to have been transported laterally over enormous distances. These slabs consisted of nearly flat-lying rocks that might be construed as undisplaced, except that they lay on top of younger rocks. In the late nineteenth century, several prominent geologists, most notably Albert Heim (1849 –1937), undertook extensive field work in the Alps to attempt to resolve their structure. Heim’s detailed field work, beautiful maps, and elegant prose convinced geological colleagues that the Alpine strata had been displaced horizontally over enormous distances. In some cases, the rocks had been accordioned so tightly that layers that previously extended horizontally for hundreds of kilometers were now reduced to distances of a few kilometers. But in even more startling cases, the rocks were scarcely folded at all, as if huge slabs of rocks had been simply lifted up from one area of the crust and laid down in another. Heim interpreted the slabs of displaced rock in his own Glarus district as a huge double fold with missing lower limbs, but in 1884 the French geologist Marcel Bertrand (1847–1907) argued that these displacements were not folds but faults. Large segments of the Alps were the result of huge faults that had thrust strata from south to north, over and on top of younger rocks. August Rothpletz (1853–1918), an Austrian geologist, realized that the Alpine thrust faults were similar to those that had been earlier described by the Rogers brothers in the Appalachians. By the late 1880s, thrust faults had been mapped in detail in North America, Scotland, and Scandinavia.

scholarly journals IMU gyroscopes are a valid alternative to 3D optical motion capture system for angular kinematics analysis in tennis

2020 ◽  
pp. 175433712096544 ◽  
Author(s):  
Gabriel Delgado-García ◽  
Jos Vanrenterghem ◽  
Emilio J Ruiz-Malagón ◽  
Pablo Molina-García ◽  
Javier Courel-Ibáñez ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Motion Capture ◽  
Correlation Coefficients ◽  
Strong Relationship ◽  
System Level ◽  
Optical Motion ◽  
Measurement Units ◽  
The Difference ◽  
Optical Motion Capture ◽  
Level Of Agreement

Whereas 3D optical motion capture (OMC) systems are considered the gold standard for kinematic assessment in sport science, they present some drawbacks that limit its use in the field. Inertial measurement units (IMUs) incorporating gyroscopes have been considered as a more practical alternative. Thus, the aim of the study was to evaluate the level of agreement for angular velocity between IMU gyroscopes and an OMC system for varying tennis strokes and intensities. In total, 240 signals of angular velocity from different body segments and types of strokes (forehand, backhand and service) were recorded from four players (two competition players and two beginners). The angular velocity of the IMU gyroscopes was compared to the angular velocity from the OMC system. Level of agreement was evaluated by correlation coefficients, magnitudes of errors in absolute and relative values and Bland-Altman plots. Differences between both systems were highly consistent within players’ skill (i.e. along the broad range of velocities) and axes ( x, y, z). Correlations ranged from 0.951 to 0.993, indicating a very strong relationship and concordance. The magnitude of the differences ranged from 4.4 to 35.4 deg·s−1. The difference relative to the maximum angular velocity achieved was less than 5.0%. The study concluded that IMUs and OMC systems showed comparable values. Thus, IMUs seem to be a valid alternative to detect meaningful differences in angular velocity during tennis groundstrokes in field-based experimentation.

scholarly journals Rotation of the Primary Component of Algol

1980 ◽  
Vol 88 ◽  
pp. 223-224
Author(s):  
S. M. Rucinski
Keyword(s):  
Numerical Model ◽  
Angular Velocity ◽  
Least Squares ◽  
Solid Body ◽  
Primary Component ◽  
Rotation Parameter ◽  
Velocity Versus ◽  
Least Squares Solution

1.8 A° segment of the Algol A spectrum centered at 1075.55 A° line of Ni II was scanned repeatedely with the 0.05 A° resolution from the Copernicus satellite. The numerical model is described in which 37 out of the total 55 scans obtained during two eclipses were combined in a least-squares solution, to determine the period of rotation and degree of non-solid rotation of Algol A. The period of rotation suggests full synchronism of rotational and orbital motions; the equatorial velocity is Ve = 53 ± 3 km/s. The non-solid rotation parameter ‘s’ measuring the distribution of angular velocity versus stellar latitude in ω = ωe (1 - s + s cos2 ϑ) has been found equal s = 0.07 ± 0.25 indicating the rotation law not far from solid body.

scholarly journals Aeolian Remobilisation of Volcanic Ash: Outcomes of a Workshop in the Argentinian Patagonia

2020 ◽  
Vol 8 ◽  
Author(s):  
Paul A. Jarvis ◽  
Costanza Bonadonna ◽  
Lucia Dominguez ◽  
Pablo Forte ◽  
Corine Frischknecht ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Friction Velocity ◽  
Critical Infrastructure ◽  
Dust Emission ◽  
Source Area ◽  
Field Measurements ◽  
Volcanic Eruptions ◽  
Field Studies ◽  
Sediment Traps ◽  
Economic Sectors

During explosive volcanic eruptions, large quantities of tephra can be dispersed and deposited over wide areas. Following deposition, subsequent aeolian remobilisation of ash can potentially exacerbate primary impacts on timescales of months to millennia. Recent ash remobilisation events (e.g., following eruptions of Cordón Caulle 2011; Chile, and Eyjafjallajökull 2010, Iceland) have highlighted this to be a recurring phenomenon with consequences for human health, economic sectors, and critical infrastructure. Consequently, scientists from observatories and Volcanic Ash Advisory Centers (VAACs), as well as researchers from fields including volcanology, aeolian processes and soil sciences, convened at the San Carlos de Bariloche headquarters of the Argentinian National Institute of Agricultural Technology to discuss the “state of the art” for field studies of remobilised deposits as well as monitoring, modeling and understanding ash remobilisation. In this article, we identify practices for field characterisation of deposits and active processes, including mapping, particle characterisation and sediment traps. Furthermore, since forecast models currently rely on poorly-constrained dust emission schemes, we call for laboratory and field measurements to better parameterise the flux of volcanic ash as a function of friction velocity. While source area location and extent are currently the primary inputs for dispersion models, once emission schemes become more sophisticated and better constrained, other parameters will also become important (e.g., source material volume and properties, effective precipitation, type and distribution of vegetation cover, friction velocity). Thus, aeolian ash remobilisation hazard and associated impact assessment require systematic monitoring, including the development of a regularly-updated spatial database of resuspension source areas.

scholarly journals Thermal Infrared Hyperspectral Imaging for Mineralogy Mapping of a Mine Face

2018 ◽  
Vol 10 (10) ◽  
pp. 1518 ◽  
Author(s):  
Stephane Boubanga-Tombet ◽  
Alexandrine Huot ◽  
Iwan Vitins ◽  
Stefan Heuberger ◽  
Christophe Veuve ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Spectral Resolution ◽  
Remote Sensing Data ◽  
Field Measurements ◽  
Thermal Infrared ◽  
Field Studies ◽  
Hyperspectral Data ◽  
Spectral Bands ◽  
Remote Sensing Systems ◽  
Viewing Perspective

Remote sensing systems are largely used in geology for regional mapping of mineralogy and lithology mainly from airborne or spaceborne platforms. Earth observers such as Landsat, ASTER or SPOT are equipped with multispectral sensors, but suffer from relatively poor spectral resolution. By comparison, the existing airborne and spaceborne hyperspectral systems are capable of acquiring imagery from relatively narrow spectral bands, beneficial for detailed analysis of geological remote sensing data. However, for vertical exposures, those platforms are inadequate options since their poor spatial resolutions (metres to tens of metres) and NADIR viewing perspective are unsuitable for detailed field studies. Here, we have demonstrated that field-based approaches that incorporate thermal infrared hyperspectral technology with about a 40-nm bandwidth spectral resolution and tens of centimetres of spatial resolution allow for efficient mapping of the mineralogy and lithology of vertical cliff sections. We used the Telops lightweight and compact passive thermal infrared hyperspectral research instrument for field measurements in the Jura Cement carbonate quarry, Switzerland. The obtained hyperspectral data were analysed using temperature emissivity separation algorithms to isolate the different contributions of self-emission and reflection associated with different carbonate minerals. The mineralogical maps derived from measurements were found to be consistent with the expected carbonate results of the quarry mineralogy. Our proposed approach highlights the benefits of this type of field-based lightweight hyperspectral instruments for routine field applications such as in mining, engineering, forestry or archaeology.

Impact of volcanic halogens on the ozone layer and climate, a look to the past to highlight the present

2020 ◽  
Author(s):  
Hélène Balcone-Boissard ◽  
Thiébaut D'Augustin ◽  
Georges Boudon ◽  
Slimane Bekki ◽  
Magali Bonifacie ◽  
...  
Keyword(s):  
Volcanic Eruptions ◽  
Field Work ◽  
Field Studies ◽  
Global Scale ◽  
Ozone Layer ◽  
Volatile Species ◽  
Magma Supply ◽  
Global Impacts ◽  
Almost All ◽  
The Impact

&lt;p&gt;Explosive eruptions of the Plinian type inject large amounts of particles (pumice, ash, aerosols) and volatile species into the atmosphere. They result from the rapid discharge of a magma chamber and involve large volumes of magma (from a km&lt;sup&gt;3&lt;/sup&gt; to hundreds of km&lt;sup&gt;3&lt;/sup&gt;). Such eruptions correspond to a rapid ascent of magma in the conduit driven by the exsolution of volatile species. If the magma supply is continuous, this jet produces a convective eruptive column that can reach tens of km in height and transports gas and particles (pumice, ash, aerosols) directly into the stratosphere. Depending on the latitude of the volcano, the volume of implied magma, the height of the eruptive plume and the composition of the released gaseous and particulate mixture, these events can strongly affect the environment at the local or even at a global scale. Almost all studies on global impacts of volcanic eruptions have largely focused on the sulfur component. Volcanoes are also responsible for the emission of halogens which have a crucial impact on the ozone layer and therefore the climate.&lt;/p&gt;&lt;p&gt;The objective of our project is to revisit the issue of the impact of volcanism on the atmosphere and climate by considering not only the sulfur component but also the halogen component. We will provide field work-based constraints on the strength of halogen (Cl and Br) emissions and on degassing processes for key eruptions, we will characterise the dynamics of volcanic plumes, notably the vertical distribution of emissions and we will explore and quantify the respective impacts of sulfur and halogen emissions on the ozone layer and climate.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Here we will shed light on the methodology that will combine field campaign, laboratory analysis of collected samples and a hierarchy of modelling tools to study. We use an approach combining field studies, petrological characterization, geochemical measurements including isotopic data, estimation of the volume of involved magma and the height of injection of gases and particles by modelling the eruptive plume dynamic and numerical simulation of the impacts at the plume scale and at the global scale. &amp;#160;The first halogen budget will also be presented.&lt;/p&gt;

Accelerating the Calibration of Multihole Pressure Probes by Applying Advanced Computational Methods

2005 ◽  
Vol 127 (3) ◽  
pp. 425-430 ◽  
Author(s):  
Arnoud R. C. Franken ◽  
Paul C. Ivey
Keyword(s):  
Computational Methods ◽  
Three Dimensional ◽  
Field Measurements ◽  
Cost Effective ◽  
Accurate Method ◽  
Pressure Probe ◽  
Calibration Data ◽  
Essential Information ◽  
Individual Probe ◽  
Probe Calibration

The miniature multihole pneumatic pressure probe is widely regarded as a cost-effective, easy-to-use, and accurate method for performing two- or three-dimensional flow field measurements in turbomachinery. The major downside to the use of these probes is that the influence of fabrication imperfections on probe characteristics necessitates an extensive and highly time-intensive and, therefore, costly calibration of each individual probe. Unless these probes can be fabricated to such standards that make individual probe calibrations superfluous, the only way to significantly reduce the time and costs associated with probe calibration is to shorten the calibration process. The latter is only possible if all essential information can be obtained from less calibration data. This paper describes an approach to the calibration of a series of multihole pressure probes in which advanced computational methods are used to make this possible. By exploiting the key features of a probe’s characteristic this approach requires only a fraction of the size of a conventional calibration database for the accurate modeling of the relationships between port pressures and flow conditions. As a result, calibration time and costs can be reduced without the sacrifice of quality.

scholarly journals Contribution of feldspar and marine organic aerosols to global ice nucleating particle concentrations

2017 ◽  
Vol 17 (5) ◽  
pp. 3637-3658 ◽  
Author(s):  
Jesús Vergara-Temprado ◽  
Benjamin J. Murray ◽  
Theodore W. Wilson ◽  
Daniel O'Sullivan ◽  
Jo Browse ◽  
...  
Keyword(s):  
Regional Distribution ◽  
Organic Aerosols ◽  
Field Measurements ◽  
Field Work ◽  
Ice Nucleation ◽  
Mixed Phase ◽  
Aerosol Composition ◽  
Desert Dust ◽  
Concentration Changes ◽  
Mixed Phase Clouds

Abstract. Ice-nucleating particles (INPs) are known to affect the amount of ice in mixed-phase clouds, thereby influencing many of their properties. The atmospheric INP concentration changes by orders of magnitude from terrestrial to marine environments, which typically contain much lower concentrations. Many modelling studies use parameterizations for heterogeneous ice nucleation and cloud ice processes that do not account for this difference because they were developed based on INP measurements made predominantly in terrestrial environments without considering the aerosol composition. Errors in the assumed INP concentration will influence the simulated amount of ice in mixed-phase clouds, leading to errors in top-of-atmosphere radiative flux and ultimately the climate sensitivity of the model. Here we develop a global model of INP concentrations relevant for mixed-phase clouds based on laboratory and field measurements of ice nucleation by K-feldspar (an ice-active component of desert dust) and marine organic aerosols (from sea spray). The simulated global distribution of INP concentrations based on these two species agrees much better with currently available ambient measurements than when INP concentrations are assumed to depend only on temperature or particle size. Underestimation of INP concentrations in some terrestrial locations may be due to the neglect of INPs from other terrestrial sources. Our model indicates that, on a monthly average basis, desert dusts dominate the contribution to the INP population over much of the world, but marine organics become increasingly important over remote oceans and they dominate over the Southern Ocean. However, day-to-day variability is important. Because desert dust aerosol tends to be sporadic, marine organic aerosols dominate the INP population on many days per month over much of the mid- and high-latitude Northern Hemisphere. This study advances our understanding of which aerosol species need to be included in order to adequately describe the global and regional distribution of INPs in models, which will guide ice nucleation researchers on where to focus future laboratory and field work.

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