Vertical Migration Comparison of Scenedesmus and Microcystis

2012 ◽  
Vol 518-523 ◽  
pp. 558-564 ◽  
Author(s):  
Yu Ling Huang ◽  
Ping Zhang ◽  
Chun Zhu ◽  
Zhao Hong Zhou
Keyword(s):  
Chlorophyll A ◽  
Light Source ◽  
Vertical Migration ◽  
Algal Bloom ◽  
Complex Structure ◽  
Sedimentation Coefficient ◽  
Light Sources ◽  
Extinction Coefficients ◽  
Viscous Forces ◽  
Cell Structures

Scenedesmus and Microcystis usually present in nutrients-enriched freshwater, adapt to the environmental conditions by vertical migration and lead to eutrophication and algal bloom, which results in deteriorated water quality and damaged aquatic ecosystem. The vertical migrations of Scenedesmus and Microcystis with three kinds of light sources were observed in columns. The concentration of chlorophyll a was analyzed to indicate the vertical migration of the algae. The results showed that the extinction coefficients’ rang for Scenedesmus was lower than that for Microcystis, which was due to the algal self shading resulted by the lower concentration of chlorophyll a. Under different illumination, Scenedesmus cells sank down to the bottom due to the gravity and thus were taken away by the samplings, whereas, Microcystis cells floated significantly in the columns all the time. The Stokes’ Law showed that under light sources of I2 and I3 and without light source, the sedimentation coefficients for Scenedesmus were higher than those for Microcystis, while under light source of I1, the sedimentation coefficient was lower than that for Microcystis. The different cell structures lead to different vertical migrating processes: Microcystis keeps balance between buoyancy and gravity using gas-filled structures, whereas, Scenedesmus suspend through clothing a large number of bristles with a complex structure around cells, resulting high viscous forces to help to reducing sinking rates.

A Method of Film Retroreflection Index Calculated by Reflectance Spectrum

2012 ◽  
Vol 503-504 ◽  
pp. 1284-1287 ◽  
Author(s):  
Yong Yang ◽  
Chuan Zheng Zhu ◽  
Yuan Yuan Bai ◽  
Wei Li
Keyword(s):  
Light Source ◽  
Reflectance Spectrum ◽  
Complex Structure ◽  
Test Methods ◽  
Light Sources ◽  
Relative Method ◽  
Uncertainty Component ◽  
Structure Adjustment ◽  
Parameter Test ◽  
Detector Angle

Retroreflective film are used widely in traffic and municipal field as information carrier, the retroreflection index is considered the most important parameter, test methods of this parameter including absolute and relative method, traditional instruments are consisted of light source, photometric detector, angle adjust device, etc. The complex structure of instrument add the uncertainty component, so reflectance spectrum is used to calculated the film retroreflection index, this method would improve the testament accuracy and provide more light sources choices without structure adjustment.

Organic Light Emitting Diodes - Innovative Light Sources

2019 ◽  
pp. 101-107
Author(s):  
Sergei A. Stakharny
Keyword(s):  
Light Source ◽  
Organic Light Emitting Diodes ◽  
Organic Leds ◽  
Light Sources ◽  
High Quality ◽  
Light Emitting ◽  
Organic Light ◽  
Lighting Systems ◽  
Physical Principles ◽  
Prospects Of Application

This article is a review of the new light source – organic LEDs having prospects of application in general and special lighting systems. The article describes physical principles of operation of organic LEDs, their advantages and principal differences from conventional non-organic LEDs and other light sources. Also the article devoted to contemporary achievements and prospects of development of this field in the spheres of both general and museum lighting as well as other spheres where properties of organic LEDs as high-quality light sources may be extremely useful.

scholarly journals Effect of red algal bloom on growth and production of carps

Our Nature ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 48-54
Author(s):  
Ram Bhajan Mandal ◽  
Sunila Rai ◽  
Madhav Kumar Shrestha ◽  
Dilip Kumar Jha ◽  
Narayan Prasad Pandit
Keyword(s):  
Water Quality ◽  
Body Weight ◽  
Chlorophyll A ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Algal Bloom ◽  
Total Dissolved Solids ◽  
Dissolved Solids ◽  
Aquaculture Farm ◽  
Red Algal

An experiment was carried to assess the effect of red algal bloom on growth and production of carp, water quality and profit from carp for 120 days at Aquaculture Farm of Agriculture and Forestry University, Chitwan. The experiment included two treatments: carp polyculture in non-red pond and carp polyculture in red pond with algal bloom each with three replicates. Carp fingerlings were stocked at 1 fish/m2 and fed with pellet containing 24% CP at 3% body weight. Net yield of rohu was found significantly higher (p<0.05) in non-red ponds (0.38±0.01 t ha-1) than red ponds (0.24±0.05 t ha-1). Survival of rohu (84.9±1.4%), bighead (95.2±2.0%) and mrigal (88.1±14.4%) were also significantly higher (p<0.05) in non-red ponds than red ponds. Red algal bloom affected DO, nitrate and chlorophyll-a, nitrite, total nitrogen, total phosphorus, total dissolved solids and conductivity. However, overall carp production and profit from carp remained unaffected.

scholarly journals Analysis on High-Power Seaport LED Luminaire with Uniform Light Distribution Based on Optimized Lens and Heatsink

2021 ◽  
Vol 11 (9) ◽  
pp. 4035
Author(s):  
Jinsheon Kim ◽  
Jeungmo Kang ◽  
Woojin Jang
Keyword(s):  
Light Source ◽  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Light Distribution ◽  
Light Sources ◽  
Led Light ◽  
High Power Led ◽  
Distribution Requirement ◽  
Lighting Application

In the case of light-emitting diode (LED) seaport luminaires, they should be designed in consideration of glare, average illuminance, and overall uniformity. Although it is possible to implement light distribution through auxiliary devices such as reflectors, it means increasing the weight and size of the luminaire, which reduces the feasibility. Considering the special environment of seaport luminaires, which are installed at a height of 30 m or more, it is necessary to reduce the weight of the device, facilitate replacement, and secure a light source with a long life. In this paper, an optimized lens design was investigated to provide uniform light distribution to meet the requirement in the seaport lighting application. Four types of lens were designed and fabricated to verify the uniform light distribution requirement for the seaport lighting application. Using numerical analysis, we optimized the lens that provides the required minimum overall uniformity for the seaport lighting application. A theoretical analysis for the heatsink structure and shape were conducted to reduce the heat from the high-power LED light sources up to 250 W. As a result of these analyses on the heat dissipation characteristics of the high-power LED light source used in the LED seaport luminaire, the heatsink with hexagonal-shape fins shows the best heat dissipation effect. Finally, a prototype LED seaport luminaire with an optimized lens and heat sink was fabricated and tested in a real seaport environment. The light distribution characteristics of this prototype LED seaport luminaire were compared with a commercial high-pressure sodium luminaire and metal halide luminaire.

scholarly journals Towards the Optimum Light Source Spectrum

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Andrew Chalmers ◽  
Snjezana Soltic
Keyword(s):  
Light Source ◽  
Large Scale ◽  
Source Spectrum ◽  
Light Sources ◽  
Luminous Efficacy ◽  
Light Emitting ◽  
Spectral Bands ◽  
Good Energy ◽  
Lighting Systems ◽  
Colour Rendering

This paper is concerned with designing light source spectra for optimum luminous efficacy and colour rendering. We demonstrate that it is possible to design light sources that can provide both good colour rendering and high luminous efficacy by combining the outputs of a number of narrowband spectral constituents. Also, the achievable results depend on the numbers and wavelengths of the different spectral bands utilized in the mixture. Practical realization of these concepts has been demonstrated in this pilot study which combines a number of simulations with tests using real LEDs (light emitting diodes). Such sources are capable of providing highly efficient lighting systems with good energy conservation potential. Further research is underway to investigate the practicalities of our proposals in relation to large-scale light source production.

Hybrid-Light-Source Stereolithography for Fabricating Macro-Objects With Micro-Textures

2021 ◽  
Author(s):  
Wenxuan Jia ◽  
Yuen-Shan Leung ◽  
Huachao Mao ◽  
Han Xu ◽  
Chi Zhou ◽  
...  
Keyword(s):  
Light Source ◽  
Dimensional Accuracy ◽  
Beam Width ◽  
Surface Structures ◽  
Light Sources ◽  
Scanning Method ◽  
Hardware System ◽  
Building Area ◽  
Micro Features ◽  
Display Resolution

Abstract Microscale surface structures are commonly found on macroscale bodies of natural creatures for their unique functions. However, it is difficult to fabricate such multi-scale geometry with conventional stereolithography processes that rely on either laser or digital micromirror device (DMD). More specifically, the DMD-based mask projection method displays the image of a cross-section of the part on the resin to fabricate the entire layer efficiently; however, its display resolution is limited by the building area. In comparison, the laser-based vector scanning method builds smooth features using a focused laser beam with desired beam-width resolution; however, it has less throughput for its sequential nature. In this paper, we studied the hybrid-light-source stereolithography process that integrates both optical light sources to facilitate the fabrication of macro-objects with microscale surface structures (called micro-textures in the paper). The hardware system uses a novel calibration approach that ensures pixel-level dimensional accuracy across the two light sources. The software system enables designing the distribution and density of specific microscale textures on a macro-object by generating projection images and laser toolpaths for the two integrated light sources. Several test cases were fabricated to demonstrate the capability of the developed process. A large fabrication area (76.8 mm × 80.0 mm) with 50 μm micro-features can be achieved with a high throughput.

scholarly journals Photobiocatalytic alcohol oxidation using LED light sources

2017 ◽  
Vol 19 (2) ◽  
pp. 376-379 ◽  
Author(s):  
M. Rauch ◽  
S. Schmidt ◽  
I. W. C. E. Arends ◽  
K. Oppelt ◽  
S. Kara ◽  
...  
Keyword(s):  
Light Source ◽  
Photocatalytic Oxidation ◽  
Alcohol Oxidation ◽  
Light Sources ◽  
Blue Led ◽  
Led Light

The photocatalytic oxidation of NADH using a flavin photocatalyst and a simple blue LED light source is reported.

scholarly journals Effect of Supplementary Light Source on Quality of Grafted Tomato Seedlings and Expression of Two Photosynthetic Genes

Agronomy ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 207 ◽  
Author(s):  
Hao Wei ◽  
Jiangtao Hu ◽  
Chen Liu ◽  
Mengzhao Wang ◽  
Jin Zhao ◽  
...  
Keyword(s):  
Light Source ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Sources ◽  
Seedling Production ◽  
White Leds ◽  
Tomato Seedlings ◽  
Photosynthetic Genes ◽  
Supplementary Lighting

Supplementary lighting is commonly used in high-quality seedling production. In this study, grafted tomato seedlings were grown for 10 days in a glasshouse with 16-h daily supplementary lighting at 100 μmol·m−2·s−1 PPFD (Photosynthetic photon flux density) from either high-pressure sodium (HPS), metal halide (MH), far-red (FR), white LEDs (Light emitting diodes) (W), or mixed LEDs (W1R2B1, where the subscript numbers indicate the ratio of the LED chips) to determine which light sources improve the seedling quality. The control seedlings did not receive any supplementary light. Physiological parameters and the expression of genes related to photosynthesis were analyzed. The results showed that root length, biomass, number of leaves, chlorophyll (SPAD), scion dry weight to height ratio (WHR), and specific leaf weight (SLW) were the greatest for grafted seedlings grown in W1R2B1. The level of root ball formation was the greatest for seedlings grown in W1R2B1, followed by those grown in W, HPS, and MH. Seedlings grown in FR did not fare well, as they were very thin and weak. Moreover, the expression of two photosynthetic genes (PsaA and PsbA) was significantly increased by W1R2B1 and W, which suggests that the plastid or nuclear genes might be regulated. The overall results suggest that W1R2B1 was the most suitable light source to enhance the quality of grafted tomato seedlings. The results of this study could be used as a reference for seedling production in glasshouses, and may provide new insights in the research on lights affecting the development of plants.

scholarly journals Detection and Analysis of the Causes of Intensive Harmful Algal Bloom in Kamchatka Based on Satellite Data

2021 ◽  
Vol 9 (10) ◽  
pp. 1092
Author(s):  
Valery Bondur ◽  
Viktor Zamshin ◽  
Olga Chvertkova ◽  
Ekaterina Matrosova ◽  
Vasilisa Khodaeva
Keyword(s):  
Chlorophyll A ◽  
Suspended Matter ◽  
Algal Bloom ◽  
Harmful Algal Bloom ◽  
Simulated Data ◽  
Region Of Interest ◽  
Chlorophyll A Concentration ◽  
Ocean Level ◽  
Radar Satellite ◽  
Sentinel 2A

In this paper, the causes of the anomalous harmful algal bloom which occurred in the fall of 2020 in Kamchatka have been detected and analyzed using a long-term time series of heterogeneous satellite and simulated data with respect to the sea surface height (HYCOM) and temperature (NOAA OISST), chlorophyll-a concentration (MODIS Ocean Color SMI), slick parameters (SENTINEL-1A/B), and suspended matter characteristics (SENTINEL-2A/B, C2RCC algorithm). It has been found that the harmful algal bloom was preceded by temperature anomalies (reaching 6 °C, exceeding the climatic norm by more than three standard deviation intervals) and intensive ocean level variability followed by the generation of vortices, mixing water masses and providing nutrients to the upper photic layer. The harmful algal bloom itself was manifested in an increase in the concentration of chlorophyll-a, its average monthly value for October 2020 (bloom peak) approached 15 mg/m3, exceeding the climatic norm almost four-fold for the region of interest (Avacha Gulf). The zones of accumulation of a large amount of biogenic surfactant films registered in radar satellite imagery correlate well with the local regions of the highest chlorophyll-a concentration. The harmful bloom was influenced by river runoff, which intensively brought mineral and biogenic suspensions into the marine environment (the concentration of total suspended matter within the plume of the Nalycheva River reached 10 mg/m3 and more in 2020), expanding food resources for microalgae.

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