Search results for "Optical method"
showing 4 items of 4 documents
Acoustic and optical variations during rapid downward motion episodes in the deep north-western Mediterranean Sea
2011
An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site of the ANTARES neutrino telescope near Toulon, France, thus providing a unique opportunity to compare high-resolution acoustic and optical observations between 70 and 170 m above the sea bed at 2475 m. The ADCP measured downward vertical currents of magnitudes up to 0.03 m s-1 in late winter and early spring 2006. In the same period, observations were made of enhanced levels of acoustic reflection, interpreted as suspended particles including zooplankton, by a factor of about 10 and of horizontal currents reaching 0.35 m s-1. These observations coincided with high light levels detected by the telescope, interpreted …
Large-Eddy Simulation in LSPIV techniques: the study of surface turbolence
2021
<p>In recent years, technological advances have been observed in environmental monitoring field, leading to a rapid spread of innovative technologies overcoming many historical challenges. In river monitoring field the use of image-based techniques provides non-intrusive measurements ensuring the best safety conditions for operators. The most used optical methods are the Large-Scale Particle Image Velocimetry (LSPIV) and the Large-Scale Particle Tracking Velocimetry (LSPTV).</p><p>In LSPIV and LSPTV techniques a floating tracer is introduced on the water surface and its motion is recorded by commercial devices (e.g. digital cameras). Resulting video…
Beobachtungen nach einer neuen optischen Methode: ein Beitrag zur Experimental-Physik
1864
Inhalt: Princip der Beobachtungs-Methode... 2 Specielle Beschreibung des Apparates... 8 Bemerkungen über den Gebrauch und die Adjustirung... 13 Schlieren in Gläsern ... 16 Beobachtungen mittels des Schlieren-Apparates... 18 Veränderung durchsichtiger Körper durch Temperatur und Druck... 19 Diffusionsbewegungen... 21 Untersuchung der Flammen... 23 Beugungsphänomene... 26 Sichtbarmachung der Schallwellen... 27 Beobachtungen über den electrischen Funken... 29 Der Inductionsfunken... 35 Der Flaschenfunken... 42 Schlussbemerkungen... 49
Optical Monitoring of Microplastics Filtrated from Wastewater Sludge and Suspended in Ethanol.
2021
The abundance of microplastics (MPs) in the atmosphere, on land, and especially in water bodies is well acknowledged. In this study, we establish an optical method based on three different techniques, namely, specular reflection to probe the medium, transmission spectroscopy measurements for the detection and identification, and a speckle pattern for monitoring the sedimentation of MPs filtrated from wastewater sludge and suspended in ethanol. We used first Raman measurements to estimate the presence and types of different MPs in wastewater sludge samples. We also used microscopy to identify the shapes of the main MPs. This allowed us to create a teaching set of samples to be characterized …