scholarly journals A Submersible Phosphate Analyzer for Marine Environments based on Inlaid Microfluidics

2021 ◽  
Author(s):  
Sean Christopher Morgan ◽  
Edward Arthur Luy ◽  
Arnold Furlong ◽  
Vincent Joseph Sieben
Keyword(s):  
Marine Environments ◽  
Short Term ◽  
Flux Dynamics ◽  
Algae Blooms ◽  
Tidal Cycles ◽  
In Situ Sensors ◽  
Phosphate Flux

In situ sensors are needed to further our understanding of phosphate flux dynamics in marine environments during short term events such as tidal cycles, algae blooms and runoff periods. Here,...

scholarly journals Biofouling protection for marine environmental sensors

Ocean Science ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 503-511 ◽  
Author(s):  
L. Delauney ◽  
C. Compère ◽  
M. Lehaitre
Keyword(s):  
Offshore Platforms ◽  
Environmental Sensors ◽  
Monitoring Networks ◽  
Short Term ◽  
In Situ Sensors ◽  
Set Up ◽  
Marine Environmental

Abstract. These days, many marine autonomous environment monitoring networks are set up in the world. These systems take advantage of existing superstructures such as offshore platforms, lightships, piers, breakwaters or are placed on specially designed buoys or underwater oceanographic structures. These systems commonly use various sensors to measure parameters such as dissolved oxygen, turbidity, conductivity, pH or fluorescence. Emphasis has to be put on the long term quality of measurements, yet sensors may face very short-term biofouling effects. Biofouling can disrupt the quality of the measurements, sometimes in less than a week. Many techniques to prevent biofouling on instrumentation are listed and studied by researchers and manufacturers. Very few of them are implemented on instruments and of those very few have been tested in situ on oceanographic sensors for deployment of at least one or two months. This paper presents a review of techniques used to protect against biofouling of in situ sensors and gives a short list and description of promising techniques.

scholarly journals Biofouling protection for marine environmental sensors

2009 ◽  
Vol 6 (3) ◽  
pp. 2993-3018 ◽  
Author(s):  
L. Delauney ◽  
C. Compère ◽  
M. Lehaitre
Keyword(s):  
Offshore Platforms ◽  
Environmental Sensors ◽  
Monitoring Networks ◽  
Short Term ◽  
In Situ Sensors ◽  
Set Up ◽  
Marine Environmental

Abstract. These days, many marine autonomous environment monitoring networks are set up in the world. These systems take advantage of existing superstructures such as offshore platforms, lightships, piers, breakwaters or are placed on specially designed buoys or underwater oceanographic structures. These systems commonly use various sensors to measure parameters such as dissolved oxygen, turbidity, conductivity, pH or fluorescence. Emphasis has to be put on the long term quality of measurements, yet sensors may face very short-term biofouling effects. Biofouling can disrupt the quality of the measurements, sometimes in less than a week. Many techniques to prevent biofouling on instrumentation are listed and studied by researchers and manufacturers. Very few of them are implemented on instruments and of those very few have been tested in situ on oceanographic sensors for deployment of at least one or two months. This paper presents a review of techniques used to protect against biofouling of in situ sensors and will give a short list and description of promising techniques.

In situ studies on alginic acid synthesis and other aspects of the metabolism of Laminaria digitata

1972 ◽  
Vol 50 (1) ◽  
pp. 177-184 ◽  
Author(s):  
Johan A. Hellebust ◽  
Arne Haug
Keyword(s):  
Amino Acids ◽  
Time Course ◽  
Alginic Acid ◽  
Acid Synthesis ◽  
Short Term ◽  
Fresh Weight Basis ◽  
Mannuronic Acid ◽  
Guluronic Acid ◽  
Rate Of Photosynthesis

Amino acids, particularly alanine and aspartate, become more strongly labeled than mannitol in short-term 14C-photoassimilation experiments. The amino acids are the most likely sources of carbon for alginic acid synthesis and respiration in the dark, in contrast to mannitol, which appears to be relatively unavailable. Temperature is very important in determining the rate of loss of recent photoassimilate in L. digitata. The rate of photosynthesis, on a fresh weight basis, is much higher for blades than for stipes.The time course for incorporation of photoassimilated carbon into alginate differs for the stipe and blade both in light and dark periods. Very little 14C enters alginate in blades in the dark, while alginate in stipes acquires considerable amounts of activity during dark periods. Alginate in both blade and stipe acquires 14C predominantly in mannuronic acid residues of their alginate during short-term photoassimilation periods, while guluronic acid residues become relatively more rapidly labeled during dark periods.

The role of forest deadwood in rockfall protection

2021 ◽  
Author(s):  
Adrian Ringenbach ◽  
Peter Bebi ◽  
Perry Bartelt ◽  
Andrin Caviezel
Keyword(s):  
Basal Area ◽  
Spruce Forest ◽  
Runout Distance ◽  
In Situ Sensors ◽  
Efficient Protection ◽  
Cost Efficient ◽  
Study Sites ◽  
Rockfall Protection

<p>Forests with a high density and basal area of living trees are known for their function as natural and cost-efficient protection against rockfall. The role of deadwood, however, is less understood. We address this knowledge gap in this contribution as we present the results of repeated real-scale experiments in a) a montane beech-spruce forest with and without deadwood and b) in a subalpine scrub mountain pine-spruce forest with deadwood. We used artificial rocks with either an equant or platy shape, masses between 45 kg and 800 kg (≈ 0.3 m3), and equipped with in-situ sensors to gain insights into rotational velocities and impact-accelerations. Clusters of deadwood and erected root plates reduced the mean runout distance at both study sites. For site a), we found that more rocks were stopped behind lying than living trees and that the stopping effect of deadwood was greater for equant compared to platy rock shapes. Site b) revealed a braking effect of scrub mountain pines for relatively small (45 kg), but also a visible reduction in rotational velocities for the 800 kg rocks sensor stream. We conclude that deadwood must be taken into account in rockfall modeling and the management of rockfall protection forests.</p>

Remotely sensed short-term changes in noctilucent algae blooms in the Bohai Sea

2021 ◽  
Vol 42 (22) ◽  
pp. 8661-8674
Author(s):  
Liang Ma ◽  
Yan Liu ◽  
Bowen Zhang ◽  
Lingxing Lu ◽  
Guangshun Sun ◽  
...  
Keyword(s):  
Bohai Sea ◽  
Remotely Sensed ◽  
Short Term ◽  
The Bohai Sea ◽  
Algae Blooms

Structural basis of muscle O2 diffusing capacity: evidence from muscle function in situ

2000 ◽  
Vol 88 (2) ◽  
pp. 560-566 ◽  
Author(s):  
Russell T. Hepple ◽  
Michael C. Hogan ◽  
Creed Stary ◽  
Donald E. Bebout ◽  
Odile Mathieu-Costello ◽  
...  
Keyword(s):  
Gastrocnemius Muscle ◽  
Capillary Density ◽  
Structural Basis ◽  
Diffusing Capacity ◽  
Diffusion Distance ◽  
Short Term ◽  
Cross Sectional ◽  
Intact Organism ◽  
Minimal Reduction

Although evidence for muscle O2 diffusion limitation of maximal O2 uptake has been found in the intact organism and isolated muscle, its relationship to diffusion distance has not been examined. Thus we studied six sets of three purpose-bred littermate dogs (aged 10–12 mo), with 1 dog per litter allocated to each of three groups: control (C), exercise trained for 8 wk (T), or left leg immobilized for 3 wk (I). The left gastrocnemius muscle from each animal was surgically isolated, pump-perfused, and electrically stimulated to peak O2 uptake at three randomly applied levels of arterial oxygenation [normoxia, arterial[Formula: see text]([Formula: see text]) 77 ± 2 (SE) Torr; moderate hypoxia, [Formula: see text]: 33 ± 1 Torr; and severe hypoxia, [Formula: see text]: 22 ± 1 Torr]. O2 delivery (ml ⋅ min−1 ⋅ 100 g− 1) was kept constant among groups for each level of oxygenation, with O2 delivery decreasing with decreasing [Formula: see text]. O2extraction (%) was lower in I than T or C for each condition, but calculated muscle O2 diffusing capacity (Dm[Formula: see text]) per 100 grams of muscle was not different among groups. After the experiment, the muscle was perfusion fixed in situ, and a sample from the midbelly was processed for microscopy. Immobilized muscle showed a 45% reduction of muscle fiber cross-sectional area ( P < 0.05), and a resulting 59% increase in capillary density ( P < 0.05) but minimal reduction in capillary-to-fiber ratio (not significant). In contrast, capillarity was not significantly different in T vs. C muscle. The results show that a dramatically increased capillary density (and reduced diffusion distance) after short-term immobilization does not improve Dm[Formula: see text] in heavily working skeletal muscle.

Distributed Modal Voltages of Nonlinear Paraboloidal Shells With Distributed Neurons

2004 ◽  
Vol 126 (1) ◽  
pp. 47-53 ◽  
Author(s):  
H. S. Tzou ◽  
J. H. Ding
Keyword(s):  
Dynamic Responses ◽  
Dynamic State ◽  
Structural Components ◽  
Shells Of Revolution ◽  
Membrane Component ◽  
Fully Integrated ◽  
In Situ Sensors ◽  
Membrane Components ◽  
Paraboloidal Shell

Effective health monitoring and distributed control of advanced structures depends on accurate measurements of dynamic responses of elastic structures. Conventional sensors used for structural measurement are usually add-on “discrete” devices. Lightweight distributed thin-film piezoelectric neurons fully integrated (laminated or embedded) with structural components can serve as in-situ sensors monitoring structure’s dynamic state and health status. This study is to investigate modal voltages and detailed signal contributions of linear or nonlinear paraboloidal shells of revolution laminated with piezoelectric neurons. Signal generation of distributed neuron sensors laminated on paraboloidal shells is defined first, based on the open-voltage assumption and Maxwell’s principle. The neuron signal of a linear paraboloidal shell is composed of a linear membrane component and a linear bending component; the signal of a nonlinear paraboloidal shell is composed of nonlinear and linear membrane components and a linear bending component due to the von Karman geometric nonlinearity. Signal components and distributed modal voltages of linear and nonlinear paraboloidal shells with various curvatures and thickness are investigated.

scholarly journals Temporal Variation of Chlorophyll-a Concentrations in Highly Dynamic Waters from Unattended Sensors and Remote Sensing Observations

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2699 ◽  
Author(s):  
Jian Li ◽  
Liqiao Tian ◽  
Qingjun Song ◽  
Zhaohua Sun ◽  
Hongjing Yu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Chlorophyll Fluorescence ◽  
Chlorophyll A ◽  
Temporal Variations ◽  
Lake Area ◽  
Short Term ◽  
Chl A ◽  
Spatio Temporal

Monitoring of water quality changes in highly dynamic inland lakes is frequently impeded by insufficient spatial and temporal coverage, for both field surveys and remote sensing methods. To track short-term variations of chlorophyll fluorescence and chlorophyll-a concentrations in Poyang Lake, the largest freshwater lake in China, high-frequency, in-situ, measurements were collected from two fixed stations. The K-mean clustering method was also applied to identify clusters with similar spatio-temporal variations, using remote sensing Chl-a data products from the MERIS satellite, taken from 2003 to 2012. Four lake area classes were obtained with distinct spatio-temporal patterns, two of which were selected for in situ measurement. Distinct daily periodic variations were observed, with peaks at approximately 3:00 PM and troughs at night or early morning. Short-term variations of chlorophyll fluorescence and Chl-a levels were revealed, with a maximum intra-diurnal ratio of 5.1 and inter-diurnal ratio of 7.4, respectively. Using geostatistical analysis, the temporal range of chlorophyll fluorescence and corresponding Chl-a variations was determined to be 9.6 h, which indicates that there is a temporal discrepancy between Chl-a variations and the sampling frequency of current satellite missions. An analysis of the optimal sampling strategies demonstrated that the influence of the sampling time on the mean Chl-a concentrations observed was higher than 25%, and the uncertainty of any single Terra/MODIS or Aqua/MODIS observation was approximately 15%. Therefore, sampling twice a day is essential to resolve Chl-a variations with a bias level of 10% or less. The results highlight short-term variations of critical water quality parameters in freshwater, and they help identify specific design requirements for geostationary earth observation missions, so that they can better address the challenges of monitoring complex coastal and inland environments around the world.

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