Effects of seawater viscosity and temperature on the movement of the marine dinoflagellate Prorocentrum minimum

2021 ◽  
Vol 86 ◽  
pp. 21-28
Author(s):  
AS Tyrell ◽  
H Jiang ◽  
NS Fisher
Keyword(s):  
Mechanical Response ◽  
Seawater Temperature ◽  
High Viscosity ◽  
Cold Temperature ◽  
Prorocentrum Minimum ◽  
Movement Direction ◽  
Coastal Species ◽  
Highly Sensitive ◽  
Modelling Studies ◽  
Viscosity Changes

It is important to understand how planktonic dinoflagellate movements may be affected by environmental conditions, including those potentially influenced by climate change. Because of their small size, dinoflagellates can be expected to be highly sensitive to changes in viscosity; however, there is currently little understanding of how these organisms and other algae may be regulated by seawater viscosity. Previous work that has addressed the effects of seawater viscosity on single-celled plankton considered unnaturally large viscosity changes from a biomechanical perspective, sometimes without considering temperature effects. We studied the swimming of the dinoflagellate Prorocentrum minimum, a common coastal species, when exposed to environmentally relevant temperature and viscosity changes. P. minimum showed an additive response to seawater viscosity and temperature: cold temperature and high viscosity both slowed swimming speeds. However, seawater temperature and viscosity did not affect the movement direction or linearity of swimming of the dinoflagellates. We argue that temperature-related changes in movement may be partially regulated by a mechanical response to viscosity, which increases at cold temperature. We also propose possible future directions for laboratory and modelling studies.

Microstructural Modelling of P91 Martensitic Steel Under Uniaxial Loading Conditions

2013 ◽  
Author(s):  
Brian Golden ◽  
Dongfeng Li ◽  
Noel O’Dowd
Keyword(s):  
Power Plant ◽  
Mechanical Response ◽  
Electron Backscatter Diffraction ◽  
Voronoi Tessellation ◽  
Peak Stress ◽  
Grain Structure ◽  
Plant Materials ◽  
Deformation And Failure ◽  
Rate Dependent ◽  
Modelling Studies

The changing face of power generation requires an improved understanding of the deformation and failure response of power plant materials. Important insights can be obtained through microstructurally motivated modelling studies. This paper deals with the comparisons of predictions of the mechanical response of a power plant steel (P91), obtained from a model with a measured microstructure with those obtained from a numerically simulated microstructure. Electron backscatter diffraction (EBSD) is employed to obtain the orientation of the martensitic grain structure of the steel. This information is incorporated within a representative volume element (RVE) to represent the material microstructure. A non-linear, rate dependent, finite strain crystal plasticity model is used to represent the deformation of the material, with the orientation of each finite-element integration point determined from the EBSD analysis. The deformation under uniaxial tension is analysed. Due to the inhomogeneous microstructure strong strain gradients are generated within the RVE even under remote homogenous strain states. It is seen that peak stress/strain states are associated with particular features of the microstructure. The results taken from the model are compared with those obtained with an equiaxed microstructure generated using the Voronoi tessellation method.

Correlation between the Force and Magnetic Field of the U71Mn Notched Sample

2015 ◽  
Vol 723 ◽  
pp. 785-788
Author(s):  
Sheng Bao ◽  
Yi Bin Gu ◽  
Sheng Nan Hu ◽  
Mei Li Fu ◽  
Da Zhang
Keyword(s):  
Magnetic Field ◽  
Tensile Stress ◽  
Mechanical Response ◽  
Nondestructive Method ◽  
Sensitive Indicator ◽  
Fluxgate Magnetometer ◽  
Piezomagnetic Effect ◽  
Highly Sensitive

In this work experiments were carried out to study the evolution of the piezomagnetic field surrounding steel samples with the tensile stress. The piezomagnetic field was recorded by a highly sensitive fluxgate magnetometer of 428D. The piezomagnetic field (B field) and its gradient of the U71Mn steel are compared with the mechanical response. Results show that the piezomagnetic response seems to be a more sensitive indicator of damage than the mechanical one. Moreover, there exhibits correlations between the piezomagnetic response and mechanical response. This research has demonstrated that the piezomagnetic effect can be utilized as a nondestructive method to monitor damage in the rail.

Screening of dicyanoisophorone-based probes for highly sensitive detection of viscosity changes in living cells and zebrafish

2021 ◽  
Vol 57 (75) ◽  
pp. 9554-9557
Author(s):  
Fanpeng Kong ◽  
Ying Li ◽  
Xiao Li ◽  
Xiaoxiu Wang ◽  
Guanyu Fu ◽  
...  
Keyword(s):  
Living Cells ◽  
Sensitive Detection ◽  
Highly Sensitive ◽  
Highly Sensitive Detection ◽  
Viscosity Changes

Screening results indicated that DCO-5 exhibited the highest sensitivity to viscosity and was insensitive to polarity or pH, and enables the successful detection of viscosity changes in vivo.

Preparedness for Heavy Oil Spills: More Focus on Mechanical Feeder Skimmers

2001 ◽  
Vol 2001 (1) ◽  
pp. 577-584 ◽  
Author(s):  
Flemming Hvidbak
Keyword(s):  
Heavy Oil ◽  
Mechanical Response ◽  
Oil Spills ◽  
High Capacity ◽  
High Viscosity ◽  
Coast Guard ◽  
Response Strategy ◽  
Test Facility ◽  
Heavy Oils ◽  
Light Oil

ABSTRACT Numerous spills over the years have demonstrated that mechanical response to heavy oil spills at sea is less than successful. Recently, after the 10,000 m3 Erika spill in France, less than 5% was recovered before the oil reached the coast. The weather played an important role, but the selection of equipment and apparent response strategy did as well. Mainly weir skimmers were used. Weir skimmers are, due to their simplicity and reliability, widely used in spills at sea. Probably because some of the well-known brands are equipped with heavy oil transfer pumps, they commonly are used in heavy oil spills. In addition, high capacity units with light oil centrifugal transfer pumps are being used on heavy oil (Erika). Weir skimmers start losing their efficiency when the viscosity of the oil exceeds certain limits. It gets too difficult for the oil to pass the weir lip and flow into the hopper so that the pump can transfer it. For very heavy oils, which barely can float, the inlet weir is an even larger obstruction. A mechanical feeder skimmer lifts or drags the oil out of the water to a position above the water surface and feeds or drops it into a collection tank or a transfer pump. The mechanical feeder principle may result in significantly increased performance regarding high viscosity, debris, and, in most cases, low water content. Recent tests at SAIC/Environment Canada's test facility in Ottawa, Canada, sponsored by the Canadian Coast Guard, demonstrated that floating bitumen with a viscosity of about 2 million cSt could be recovered by mechanical feeder skimmers, while a “high viscosity” weir skimmer had no effect. This puts the Erika's viscosity of “only” 200,000 cSt into perspective, and strongly point at mechanical feeder skimmers in the preparedness for heavy oil spills.

scholarly journals Separating viscous and thermal effects of temperature on copepod feeding

2019 ◽  
Vol 41 (6) ◽  
pp. 865-878 ◽  
Author(s):  
Abigail S Tyrell ◽  
Nicholas S Fisher
Keyword(s):  
Thermal Effects ◽  
Seawater Temperature ◽  
High Viscosity ◽  
Mechanical Effect ◽  
Cold Temperatures ◽  
Thermally Induced ◽  
Temperature Changes ◽  
Constant Viscosity ◽  
Parvocalanus Crassirostris ◽  
Q10 Values

Abstract Because seawater temperature is correlated with viscosity, temperature changes may impact small zooplankton through a mechanical pathway, separately from any thermally-induced effects on metabolism. We evaluated both viscous and thermal effects on copepod feeding in experiments where viscosity was manipulated separately from temperature using a non-toxic polymer. Two copepod species, Acartia tonsa and Parvocalanus crassirostris, feeding on two monoalgal diets (a diatom and a dinoflagellate) were compared. At constant temperature, increase in viscosity nearly always reduced feeding; at constant viscosity, changes in temperature had no effect on feeding. The effects of viscosity and temperature were more pronounced for the diatom than the flagellate prey. Overall, reductions in zooplankton feeding at cold temperatures can be explained primarily by the mechanical effect of viscosity. Q10 values for copepod feeding (1.0–7.9), calculated from the present data and from the literature, were generally higher and more variable than Q10 values from the literature for copepod respiration (1.5–3.1) indicating that, at cold temperatures, feeding is more dramatically suppressed than metabolism. We conclude that (i) high viscosity may inhibit copepod feeding, and (ii) this viscous effect on feeding (rather than a thermal effect on metabolism) may influence the cold-temperature bounds of zooplankton populations.

A highly sensitive red-emitting probe for the detection of viscosity changes in living cells, zebrafish, and human blood samples

2020 ◽  
Vol 8 (6) ◽  
pp. 1310-1315 ◽  
Author(s):  
Manlin Fu ◽  
Wei Shen ◽  
Yajun Chen ◽  
Wenjun Yi ◽  
Chunhui Cai ◽  
...  
Keyword(s):  
Human Blood ◽  
Fluorescent Probes ◽  
Living Cells ◽  
The State ◽  
Blood Samples ◽  
Highly Sensitive ◽  
Human Blood Samples ◽  
Viscosity Changes

Intracellular viscosity can be measured to reflect the state of living cells. Fluorescent probes are powerful tools for viscosity detection in vivo.

scholarly journals PROLIFERATION OF Amphidinium carterae (GYMNODINIALES: GYMNODINIACEAE) IN BAHÍA DE LA PAZ, GULF OF CALIFORNIA

2012 ◽  
Vol 27 (2) ◽  
pp. 37 ◽  
Author(s):  
I. Gárate -Lizárraga
Keyword(s):  
Gulf Of California ◽  
New Records ◽  
Seawater Temperature ◽  
Prorocentrum Minimum ◽  
Benthic Species ◽  
La Paz ◽  
Amphidinium Carterae ◽  
The Pacific

During a sampling on 15 December 2011 in Bahía de La Paz, a bloom of the benthic dinoflagellate Amphidinium carterae was detected. Its abundance ranged from 28.2 to 64.8 × 103 cells L–1. Cells of A. carterae varied in length from 18 to 28 μm and 13 to 18 μm in wide (n = 30). The presence of A. carterae and benthic species of diatoms and dinoflagellates at the surface could be an indicator of upwelling water generated by northwestern winds. Seawater temperature during the bloom was 20 °C. Also, new records of dinoflagellates for the Mexican coast of the Pacific are here reported: Amphidiniopsis hirsuta, Amphidiniopsis sp., Amylax buxus, Cochlodinium pulchellum, Cochlodinium virescens, Durinskia cf. baltica, Gyrodinium sp., Thecadinium sp., and Prorocentrum minimum var. triangulatum. Proliferación de Amphidinium carterae (Dinophyceae: Gymnodiniales) en Bahía de La Paz, Golfo de California Durante un muestreo realizado el 15 de Diciembre de 2011 en Bahía de La Paz se detectó un florecimiento del dinoflagelado bentónico Amphidinium carterae. Los valores de abundancia variaron de 28.2 a 64.8 × 103 céls L–1. Los especímenes de A. carterae presentaron un intervalo de tallas de 18 a 28 μm de longitud y de 13 a 18 μm de ancho (n = 30). La presencia de A. carterae, así como de especies bentónicas de diatomeas y dinflagelados en superficie podrían indicar aguas de surgencia debido a la influencia de los vientos del noroeste en esta temporada. La temperatura del agua durante el florecimiento fue de 20 °C. También se reportan nuevos registros de dinoflagelados para la costa pacífica de México: Amphidiniopsis hirsuta, Amphidiniopsis sp., Amylax buxus, Cochlodinium pulchellum, Cochlodinium virescens, Durinskia cf. baltica, Gyrodinium sp., Thecadinium y Prorocentrum minimum var. triangulatum.

scholarly journals Flagellar ultrastructure suppresses buckling instabilities and enables mammalian sperm navigation in high-viscosity media

2019 ◽  
Vol 16 (152) ◽  
pp. 20180668 ◽  
Author(s):  
Hermes Gadêlha ◽  
Eamonn A. Gaffney
Keyword(s):  
Mechanical Model ◽  
Mechanical Response ◽  
Surrounding Medium ◽  
Human Sperm ◽  
High Viscosity ◽  
Virtual Human ◽  
Mammalian Sperm ◽  
Flagellar Beat ◽  
The Impact

Eukaryotic flagellar swimming is driven by a slender motile unit, the axoneme, which possesses an internal structure that is essentially conserved in a tremendous diversity of sperm. Mammalian sperm, however, which are internal fertilizers, also exhibit distinctive accessory structures that further dress the axoneme and alter its mechanical response. This raises the following two fundamental questions. What is the functional significance of these structures? How do they affect the flagellar waveform and ultimately cell swimming? Hence we build on previous work to develop a mathematical mechanical model of a virtual human sperm to examine the impact of mammalian sperm accessory structures on flagellar dynamics and motility. Our findings demonstrate that the accessory structures reinforce the flagellum, preventing waveform compression and symmetry-breaking buckling instabilities when the viscosity of the surrounding medium is increased. This is in agreement with previous observations of internal and external fertilizers, such as human and sea urchin spermatozoa. In turn, possession of accessory structures entails that the progressive motion during a flagellar beat cycle can be enhanced as viscosity is increased within physiological bounds. Hence the flagella of internal fertilizers, complete with accessory structures, are predicted to be advantageous in viscous physiological media compared with watery media for the fundamental role of delivering a genetic payload to the egg.

scholarly journals Formability of Ultrasonically Additive Manufactured Ti-Al Thin Foil Laminates

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3402 ◽  
Author(s):  
Kaya ◽  
Cora ◽  
Koç
Keyword(s):  
Biaxial Loading ◽  
Mechanical Response ◽  
Laminated Composite ◽  
Thin Foil ◽  
Movement Direction ◽  
Bulge Test ◽  
Strain Rates ◽  
Test Results ◽  
Thin Foils ◽  
Hydraulic Bulge

This study investigates the effect of strain rates and temperatures on the mechanical behavior of ultrasonically consolidated Titanium–Aluminum thin foils to understand and characterize their formability. To this goal, laminated composite samples with a distinct number of layers were bonded using ultrasonic consolidation. Then, tensile and biaxial hydraulic bulge tests at different strain rates and temperature conditions were conducted. The effect of the sample orientation on the mechanical response was also examined. Tensile and hydraulic bulge tests results were compared to observe differences in ultimate tensile strength and strain levels under uniaxial and biaxial loading conditions. The effects of loading condition, strain rate, and temperature on the material response were analyzed and discussed on the basis of test results. In general, it was concluded that the maximum elongation values attained were higher for the samples subtracted along the sonotrode movement direction compared to those obtained from the normal to sonotrode movement direction. The elongation was obtained as high as 46% for seven bi-layered samples at high-temperature ranges of 200–300 °C. Hydraulic bulge test results showed that elongation improved as the number of bi-layers increased, yet the ultimate strength values did not change significantly indicating an expansion of the formability window.

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

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