The impact of turbulent fluctuations on light propagation in a controlled environment

2014 ◽  
Author(s):  
Silvia Matt ◽  
Weilin Hou ◽  
Wesley Goode
Keyword(s):  
Light Propagation ◽  
Controlled Environment ◽  
Turbulent Fluctuations ◽  
The Impact

scholarly journals Towards Transabdominal Functional Photoacoustic Imaging of the Placenta: Improvement in Imaging Depth Through Optimization of Light Delivery

2021 ◽  
Author(s):  
Kristie Huda ◽  
Kenneth F. Swan ◽  
Cecilia T. Gambala ◽  
Gabriella C. Pridjian ◽  
Carolyn L. Bayer
Keyword(s):  
Delivery System ◽  
Light Propagation ◽  
Ex Vivo ◽  
Photoacoustic Imaging ◽  
Incidence Angle ◽  
Incident Angle ◽  
Placental Tissue ◽  
Light Delivery ◽  
Imaging Depth ◽  
The Impact

AbstractFunctional photoacoustic imaging of the placenta could provide an innovative tool to diagnose preeclampsia, monitor fetal growth restriction, and determine the developmental impacts of gestational diabetes. However, transabdominal photoacoustic imaging is limited in imaging depth due to the tissue’s scattering and absorption of light. The aim of this paper was to investigate the impact of geometry and wavelength on transabdominal light delivery. Our methods included the development of a multilayer model of the abdominal tissue and simulation of the light propagation using Monte Carlo methods. A bifurcated light source with varying incident angle of light, distance between light beams, and beam area was simulated to analyze the effect of light delivery geometry on the fluence distribution at depth. The impact of wavelength and the effects of variable thicknesses of adipose tissue and muscle were also studied. Our results showed that the beam area plays a major role in improving the delivery of light to deep tissue, in comparison to light incidence angle or distance between the bifurcated fibers. Longer wavelengths, with incident fluence at the maximum permissible exposure limit, also increases fluence within deeper tissue. We validated our simulations using a commercially available light delivery system and ex vivo human placental tissue. Additionally, we compared our optimized light delivery to a commercially available light delivery system, and conclude that our optimized geometry could improve imaging depth more than 1.6×, bringing the imaging depth to within the needed range for transabdominal imaging of the human placenta.

Effect of compost in phytoremediation of diesel-contaminated soils

2001 ◽  
Vol 43 (2) ◽  
pp. 291-295 ◽  
Author(s):  
J. Vouillamoz ◽  
M. W. Milke
Keyword(s):  
Moisture Content ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Petroleum Hydrocarbons ◽  
Dilution Effect ◽  
Screening Tests ◽  
Total Petroleum Hydrocarbons ◽  
Controlled Environment ◽  
Grass Growth ◽  
The Impact

The effect of compost on phytoremediation of diesel-contaminated soils was investigated using 130 small (200 g) containers in two screening tests. The experiments were conducted in a controlled environment using ryegrass from seed. Containers were destructively sampled at various times and analyzed for plant mass and total petroleum hydrocarbons. The results indicate that the presence of diesel reduces grass growth, and that compost helps reduced the impact of diesel on grass growth. The addition of compost helps increase diesel loss from the soils both with and without grass, though the addition of grass leads to lower diesel levels compared with controls. A second set of experiments indicates that the compost helps in phytoremediation of diesel-contaminated soil independent of the dilution effect that compost addition has. The results indicate that the compost addition allowed diesel loss down to 200 mg TPH/kg even though the compost would be expected to hold the diesel more tightly in the soil/compost mixture. The simplicity of the screening tests led to difficulties in controlling moisture content and germination rates. The conclusion of the research is that the tilling of compost into soils combined with grass seeding appears to be a valuable option for treating petroleum-contaminated soils.

scholarly journals Effect of Radiation and Temperature on Cranberry Photosynthesis and Characterization of Diurnal Change in Photosynthesis

2004 ◽  
Vol 129 (1) ◽  
pp. 106-111 ◽  
Author(s):  
S. Kumudini
Keyword(s):  
Net Photosynthesis ◽  
Vaccinium Macrocarpon ◽  
Controlled Environment ◽  
Photosynthetic Response ◽  
Radiation Level ◽  
Photosynthetic Rates ◽  
Air Temperatures ◽  
Predicted Values ◽  
The Impact

Cranberry [Vaccinium macrocarpon (Ait.)] yield has been associated with photosynthate supply. However, the impact of temperature and radiation on photosynthesis of the cranberry plant is not well understood. The objective of this experiment was to characterize the photosynthetic response to radiation and temperature in order to develop a model for estimation of cranberry photosynthetic rates. Two cranberry cultivars, `Stevens' and `Ben Lear', were tested for photosynthetic response at air temperatures ranging from 15 to 35 °C and radiation intensities from 200 to 1200 μmol·m-2·s-1. Depending on temperature, maximum photosynthesis (Pmax) was ≈10 or 12 μmol CO2/m2/s (net photosynthesis) and the saturating radiation level was estimated to be 600 to 800 μmol·m-2·s-1. Cranberry quantum yield was estimated as 0.03 mol CO2/mol photon. Both models; Blackman and the nonrectangular hyperbola with a Θ (angle of curvature) of 0.99 were a good fit for measured photosynthetic rates under controlled environment conditions. The disparity between modeled predicted values, and observed values in the field around midday, indicates a reduction in potential photosynthetic rates in a diurnal cycle that is consistent with the phenomenon of midday depression.

scholarly journals Effects of long-term closed environment on human saliva microbiota and salivary cytokines

2020 ◽  
Author(s):  
Yinzhen Zhu ◽  
Zikai Hao ◽  
Yuming Fu ◽  
Jianlou Yang ◽  
Chen Dong ◽  
...  
Keyword(s):  
Human Saliva ◽  
Mucosal Barrier ◽  
Future Research ◽  
Controlled Environment ◽  
List Type ◽  
Tnf Α ◽  
Normal Environment ◽  
The Difference ◽  
Sharing Space ◽  
The Impact

AbstractCompared with the normal environment, the microbiota in controlled closed cabins such as space capsules, Lunar/Mars bases have changed. To ensure the health of crewmembers, it’s necessary to understand the effects of these changes on human symbiotic microorganisms and immunity. In this study, the experimental platform “Lunar Palace 1” with a similar closed and controlled environment was used to research the effects of changed microbial exposure on human saliva microbiota and salivary cytokines. This paper studied on four crewmembers who participated in the third phase of the “Lunar Palace 365” experiment, analyzing the dynamic changes of saliva microbiota and salivary cytokines, and further studying the correlation between salivary cytokines and highly abundant genera. According to our data, the crewmembers’ saliva microbiota and salivary cytokines fluctuated smoothly throughout the whole experiment. Although a part of microbes increased or decreased some times, they recovered quickly after leaving the controlled environment. The level of IL-6, IL-10 and TNF-α in crewmembers’ saliva decreased from normal environment to the controlled environment, showing reduced levels of oral inflammatory response in crewmembers. In addition, although there were significant individual differences in crewmembers’ saliva microbiota, sharing living space reduced the difference. Furthermore, the level of TNF-α showed a consistent positive correlation with the abundance of Actinomyces and Rothia in the controlled environment, indicating healthy individuals’ oral mucosal barrier may be sensitive to changes in saliva microbiota. According to the result, semi-sterile environments in controlled closed cabins didn’t cause persistent changes in human saliva microbiota and oral immunity. Besides, it provides a new idea for future research on the impact of the controlled environment on crewmembers health, and provides guidance for studying the effect of semi-sterile environments on human immunity based on saliva microbiota.Key pointsSaliva microbes kept stable for individual but got convergent when sharing space;The level of salivary cytokines reduced after entering the controlled environment;There were complex correlations between salivary cytokines and saliva microbes;The crewmembers adapt well to the controlled environment.

scholarly journals Disentangling photoperiod from hop vernalization and dormancy for global production and speed breeding

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
William L. Bauerle
Keyword(s):  
Plant Traits ◽  
Humulus Lupulus ◽  
Controlled Environment ◽  
Yield And Quality ◽  
Flower Yield ◽  
Series Of Experiments ◽  
The Impact ◽  
The Way

Abstract Humulus lupulus L. (hop) flowers are a key ingredient in beer, imparting the beverage’s aroma and bitterness profile. Photoperiod is known to interact with temperature to control flowering in hops. Studies have stipulated that resting dormant buds on hops require a minimum chilling duration for their meristems to break dormancy and grow fruitfully. This assertion, in part, led to a long-held notion that hops require vernalization and/or dormancy for the meristem to change from a vegetative to floral state. The research in this study aims to separate photoperiod from vernalization and dormancy through a series of experiments that artificially control photoperiod to prevent the onset of dormancy and chilling exposure. Six experiments were performed to assess flower yield and quality for seven diverse hop cultivars (with and without exposure to chilling and dormancy) to quantify the impact on flowering performance. Vernalization and dormancy, two plant traits previously considered necessary to the proliferation of hop flowers, do not influence hop flower yield and quality. The findings have broad implications; global hop production can be distributed more widely and it paves the way for speed breeding and controlled-environment production to achieve 4 hop generation cycles per year, as opposed to 1 under field-grown conditions.

Microthermography of diode lasers: The impact of light propagation on image formation

2009 ◽  
Vol 105 (1) ◽  
pp. 014502 ◽  
Author(s):  
Julien LeClech ◽  
Mathias Ziegler ◽  
Jayanta Mukherjee ◽  
Jens W. Tomm ◽  
Thomas Elsaesser ◽  
...  
Keyword(s):  
Light Propagation ◽  
Diode Lasers ◽  
Image Formation ◽  
The Impact

Role of Turbulence in Precessing Vortex Core Dynamics

2019 ◽  
Author(s):  
Ashwini Karmarkar ◽  
Mark Frederick ◽  
Sean Clees ◽  
Danielle Mason ◽  
Jacqueline O’Connor
Keyword(s):  
Large Scale ◽  
Swirling Flows ◽  
Base Flow ◽  
Van Der Pol Oscillator ◽  
Intensity Increase ◽  
Swirl Number ◽  
Time Resolved ◽  
Turbulent Fluctuations ◽  
Eddy Viscosity Model ◽  
The Impact

Abstract Precessing vortex cores (PVC), arising from a global instability in swirling flows, can dramatically alter the dynamics of swirl-stabilized flames. Previous study of these instabilities has identified their frequencies and potential for interaction with the shear layer instabilities also present in swirling flows. In this work, we investigate the dynamics of precessing vortex cores at a range of swirl numbers and the impact that turbulence, which tends to increase with swirl number due to the increase in mean shear, has on the dynamics of this instability. This is particularly interesting as stability predictions have previously incorporated turbulence effects using an eddy viscosity model, which only captures the impact of turbulence on the base flow, not on the instantaneous dynamics of the PVC itself. Time-resolved experimental measurements of the three-component velocity field at ten swirl numbers show that at lower swirl numbers, the PVC is affected by turbulence through the presence of vortex jitter. With increasing swirl number, the PVC jitter decreases as the PVC strength increases. There is a critical swirl number below which jitter of the PVC vortex monotonically increases with increasing swirl number, and beyond which the jitter decreases, indicating that the strength of the PVC dominates over turbulent fluctuations at higher swirl numbers, despite the fact that the turbulence intensities continue to rise with increasing swirl number. Further, we use a nonlinear van der Pol oscillator model to explain the competition between the random turbulent fluctuations and coherent oscillations of the PVC. The results of this work indicate that while both the strength of the PVC and magnitude of turbulence intensity increase with increasing swirl number, there are defined regimes where each of them hold a stronger influence on the large-scale, coherent dynamics of the flow field.

Effects of turbulent fluctuations on phase partitioning in adiabatic mixed-phase cloud parcels

2021 ◽  
Author(s):  
Daniel Gomes Albuquerque ◽  
Gustavo Coelho Abade ◽  
Hanna Pawłowska
Keyword(s):  
Turbulent Mixing ◽  
Scalar Fields ◽  
Mixed Phase ◽  
Liquid Droplets ◽  
Growth Environment ◽  
Phase Partitioning ◽  
Turbulent Fluctuations ◽  
Locally Homogeneous ◽  
The Impact ◽  
Local Variability

<p>Several microphysical processes determine phase partitioning between ice and liquid water in a mixed-phase cloud. Here we investigate the collective growth of ice particles and liquid droplets affected by turbulent fluctuations in temperature and water vapor fields. All cloud particles, including inactivated nuclei (both CCN and IN), are described by Lagrangian super-particles. To account for local variability in the turbulent cloud environment we apply a Lagrangian microphysical scheme, where temperature and vapor mixing ratio are stochastic attributes attached to each super-particle. In addition, a simple linear relaxation scheme models turbulent mixing of the scalar fields probed by each super-particle. The limit of a locally homogeneous growth environment corresponds to an infinitely short turbulent mixing timescale. The impact of our Lagrangian microphysical scheme on phase partitioning is tested in adiabatic cloud parcel simulations. Results are confronted with idealized reference simulations that use bulk microphysics based on an assumed (temperature-dependent) phase partitioning function. Our study suggests that accounting for local variability in a turbulent cloud is important for reproducing steady-state mixed-phase conditions.</p>

scholarly journals Photosynthetic Responses of Swiss Chard, Kale, and Spinach Cultivars to Irradiance and Carbon Dioxide Concentration

HortScience ◽  
2017 ◽  
Vol 52 (5) ◽  
pp. 706-712 ◽  
Author(s):  
John Erwin ◽  
Esther Gesick
Keyword(s):  
Carbon Dioxide ◽  
Dark Respiration ◽  
Carbon Dioxide Concentration ◽  
Controlled Environment ◽  
Plant Responses ◽  
Whole Plant ◽  
Swiss Chard ◽  
Spinacea Oleracea ◽  
Photosynthetic Responses ◽  
The Impact

The impact of irradiance (0–1200 μmol·m−2·s−1) and carbon dioxide concentration (CO2; 50–1200 ppm) on kale (Brassica oleracea and B. napus pabularia; three cultivars), Swiss chard (chard, Beta vulgaris; four cultivars), and spinach (Spinacea oleracea; three cultivars) photosynthetic rate (Pn; per area basis) was determined to facilitate maximizing yield in controlled environment production. Spinach, chard, and kale maximum Pn were 23.8, 20.3, and 18.2 μmol CO2·m−2·s−1 fixed, respectively, across varieties (400 ppm CO2). Spinach and kale had the highest and lowest light compensation points [LCPs (73 and 13 μmol·m−2·s−1, respectively)] across varieties. The light saturation points (LSPs) for chard and kale were similar at 884–978 μmol·m−2·s−1, but for spinach, the LSP was higher at 1238 μmol·m−2·s−1. Dark respiration was lowest on kale and highest on spinach (−0.83 and −5.00 μmol CO2·m−2·s−1, respectively). The spinach CO2 compensation point (CCP) was lower (56 ppm) than the chard or kale CCP (64–65 ppm). Among varieties, ‘Red Russian’ kale Pn saturated at the lowest CO2 concentration (858 ppm), and ‘Bright Lights’ chard saturated at the highest (1266 ppm; 300 μmol·m−2·s−1). Spinach Pn was more responsive to increasing irradiance than to CO2. Kale Pn was more responsive to increasing CO2 than to irradiance, and chard Pn was equally responsive to increasing CO2 or irradiance. Implications and limitations of this work when “upscaling” to whole-plant responses are discussed.

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