Contribution of floating macrophytes (Lemna sp.) to pond modelization

2005 ◽  
Vol 51 (12) ◽  
pp. 283-289
Author(s):  
H. Jupsin ◽  
H. Richard ◽  
J.L. Vasel
Keyword(s):  
Growth Rate ◽  
Oxygen Transfer ◽  
Digital Image Analysis ◽  
Surface Coverage ◽  
Deterministic Model ◽  
Rate Coefficients ◽  
Oxygen Balance ◽  
Nitrogen And Phosphorus ◽  
Experimental Conditions ◽  
Floating Macrophytes

The objective of the present study was to develop a methodology for the quantification of the growth rate of Lemnaceae biomass by digital image analysis. The effect of biomass surface coverage on the oxygen transfer coefficient (Kla) was also quantified. Contribution of Lemnaceae to oxygen balance was evaluated by closed respirometry. Monod-like equations could be derived from growth rate coefficients in various experimental conditions. This opens the way to a deterministic model of Lemnaceae ponds where uptake of nitrogen and phosphorus (even heavy metals) can be calculated.

scholarly journals TESTING OF TWO‐STAGE CULTIVATION OF DUNALIELLA SALINA TEOD. (TEODORESCO, 1905) IN THE SEVASTOPOL REGION

2019 ◽  
Vol 14 (2) ◽  
pp. 211-220 ◽  
Author(s):  
I. N. Gudvilovich ◽  
A. B. Borovkov
Keyword(s):  
Growth Rate ◽  
Biological Research ◽  
Nitrogen And Phosphorus ◽  
Two Stage ◽  
Experimental Conditions ◽  
Additional Increase ◽  
Average Growth ◽  
Chl A ◽  
Surface Irradiance ◽  
Β Carotene

Aim. In this work, we set out to study the effect of surface irradiance on the growth rate and the pigment ratio of D. salina, as well as to test a technology for semi‐industrial cultiva‐ tion of D. salina aimed at obtaining its biomass enriched with β‐carotene.Methods. D. salina was cultivated under semi‐industrial conditions in a greenhouse module of the A. O. Kovalevsky Institute of Marine Biological Research. Square tanks (1 × 1 m) lined with polyethylene film and laid on a flat ground surface were used as propagators. The culture layer had a thickness of 10 cm and a volume of 100 litres. Pre‐grown D. salina was diluted using fresh medium without salts – sources of nitrogen and phosphorus. Dunaliella was cultivated under natural light with continuous stirring.Results. We determined the range of surface irradiance, which can be considered optimal for intensive cultivation of D. salina in terms of energy and mineral costs. Across this range, the average growth rate of the culture under experimental conditions amounted to 0.23–0.27 g DW/(l∙day), whereas the ratio of Car / Chl a increased by a factor of 1.5‐ 2, which indicates changes in the pigment composition of D. salina. It is experimentally shown that the content of carotenoids in the tanks increased by 1.3 times amounting to 600 mg per 1 m2 at a Car/Chl a ratio of 4.5 at the second stage of D. salina cultivation.Conclusions. Carotenoid accumulation during semi‐industrial cultivation of D. salina occures due to two factors: in‐ creased natural irradiance and temperature without an additional increase in salinity and blowing of carbon dioxide, which reduces the costs of its industrial cultivation. This two‐stage cultivation method can be used to develop a technology for obtaining Dunaliella biomass enriched with β‐carotene in the southern regions of the Russian Federation.   

scholarly journals LED Illumination Spectrum Manipulation for Increasing the Yield of Sweet Basil (Ocimum basilicum L.)

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 344
Author(s):  
Md Momtazur Rahman ◽  
Mikhail Vasiliev ◽  
Kamal Alameh
Keyword(s):  
Growth Rate ◽  
Fold Increase ◽  
Photosynthetic Photon Flux Density ◽  
Ocimum Basilicum ◽  
Photon Flux ◽  
Photon Flux Density ◽  
White Led ◽  
Experimental Conditions ◽  
Sweet Basil ◽  
Optimal Illumination

Manipulation of the LED illumination spectrum can enhance plant growth rate and development in grow tents. We report on the identification of the illumination spectrum required to significantly enhance the growth rate of sweet basil (Ocimum basilicum L.) plants in grow tent environments by controlling the LED wavebands illuminating the plants. Since the optimal illumination spectrum depends on the plant type, this work focuses on identifying the illumination spectrum that achieves significant basil biomass improvement compared to improvements reported in prior studies. To be able to optimize the illumination spectrum, several steps must be achieved, namely, understanding plant biology, conducting several trial-and-error experiments, iteratively refining experimental conditions, and undertaking accurate statistical analyses. In this study, basil plants are grown in three grow tents with three LED illumination treatments, namely, only white LED illumination (denoted W*), the combination of red (R) and blue (B) LED illumination (denoted BR*) (relative red (R) and blue (B) intensities are 84% and 16%, respectively) and a combination of red (R), blue (B) and far-red (F) LED illumination (denoted BRF*) (relative red (R), blue (B) and far-red (F) intensities are 79%, 11%, and 10%, respectively). The photosynthetic photon flux density (PPFD) was set at 155 µmol m−2 s−1 for all illumination treatments, and the photoperiod was 20 h per day. Experimental results show that a combination of blue (B), red (R), and far-red (F) LED illumination leads to a one-fold increase in the yield of a sweet basil plant in comparison with only white LED illumination (W*). On the other hand, the use of blue (B) and red (R) LED illumination results in a half-fold increase in plant yield. Understanding the effects of LED illumination spectrum on the growth of plant sweet basil plants through basic horticulture research enables farmers to significantly improve their production yield, thus food security and profitability.

Prediction of dissolved oxygen concentration along sanitary sewers

1996 ◽  
Vol 34 (5-6) ◽  
pp. 525-532 ◽  
Author(s):  
J. Saldanha Matos ◽  
E. Ribeiro de Sousa
Keyword(s):  
Mathematical Model ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Oxygen Transfer ◽  
Oxygen Balance ◽  
Dissolved Oxygen Concentration ◽  
Empirical Expression ◽  
Slime Layer ◽  
Sanitary Sewers ◽  
The Mathematical Model

The oxygen balance in wastewater collection systems is important in respect to the degree of biological oxidation that occurs within the stream and in respect to the control of septicity and its effects. In this paper, a simple mathematical model is presented, in order to predict dissolved oxygen concentration profiles along sanitary sewers. The mathematical model was developed based on an analytical solution of the simple differential equation of dissolved oxygen balance in sewers, and includes an empirical expression for prediction of dissolved oxygen transfer to the slime layer on the pipe walls. Because the factors controlling dissolved oxygen balance in sewers are so complex, it would be unrealistic to expect, that with this rather simple model, dissolved oxygen concentrations can be accurately predicted. Nevertheless, it is reasonable to suppose that the predictions may be adequate for some design and operation purposes.

scholarly journals Demographic aspects of Chrysomya megacephala (Diptera, Calliphoridae) adults maintained under experimental conditions: reproductive rate estimates

2006 ◽  
Vol 49 (3) ◽  
pp. 457-461 ◽  
Author(s):  
Marcelo Henrique de Carvalho ◽  
Claudio José Von Zuben
Keyword(s):  
Growth Rate ◽  
Life Expectancy ◽  
Reproductive Rate ◽  
Demographic Parameters ◽  
Intrinsic Growth Rate ◽  
Experimental Conditions ◽  
Chrysomya Megacephala ◽  
Finite Growth ◽  
Life Expectancy Estimate ◽  
Age Estimates

The objective of this work was to evaluate some aspects of the populational ecology of Chrysomya megacephala, analyzing demographic aspects of adults kept under experimental conditions. Cages of C. megacephala adults were prepared with four different larval densities (100, 200, 400 and 800). For each cage, two tables were made: one with demographic parameters for the life expectancy estimate at the initial age (e0), and another with the reproductive rate and average reproduction age estimates. Populational parameters such as the intrinsic growth rate (r) and the finite growth rate (lambda) were calculated as well.

Effects of Bacteriophage P100 at Different Concentrations on the Structural Parameters of Listeria monocytogenes Biofilms

2018 ◽  
Vol 81 (12) ◽  
pp. 2040-2044 ◽  
Author(s):  
CRISTINA RODRÍGUEZ-MELCÓN ◽  
ROSA CAPITA ◽  
CAMINO GARCÍA-FERNÁNDEZ ◽  
CARLOS ALONSO-CALLEJA
Keyword(s):  
Image Analysis ◽  
Listeria Monocytogenes ◽  
Laser Scanning ◽  
Digital Image Analysis ◽  
Surface Coverage ◽  
Structural Parameters ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Foodborne Diseases ◽  
Average Thickness

ABSTRACT Because listeriosis is one of the deadliest foodborne diseases, controlling and eradicating Listeria monocytogenes biofilms is a serious challenge for food safety. Biofilms (24 h old) formed on polystyrene by a L. monocytogenes strain of food origin were exposed for a further 24 h to 12 different concentrations (from 100 to 1011 PFU/mL) of the bacteriophage P100 (Listex P100). The structural parameters of biofilms were studied by using confocal laser scanning microscopy and digital image analysis. The biovolume in the observation field (14,121 μm2) of control (untreated) biofilms was 237,333.1 ± 2,692.6 μm3. The biomass of treated biofilms ranged from 164.7 ± 89.0 μm3 (biofilms exposed to 1010 PFU/mL) to 231,170.5 ± 15,142.0 μm3 (100 PFU/mL). The lowest biomass was achieved after treatment with 108 PFU/mL, with no further decrease in biovolume when higher phage concentrations were used. A strong (P < 0.001) correlation was found between phage concentration (log units) and biovolume (−0.965), surface coverage (−0.939), roughness (0.976), maximum thickness (−0.853), and average thickness (−0.965). Findings from this research suggest that bacteriophage P100 at concentrations equal to or greater than 8 log PFU/mL successfully removes L. monocytogenes biofilms from polystyrene surfaces.

scholarly journals Manipulation of growth of the Amazonian fish tambaqui, Colossoma macropomum (Characiformes: Serrasalmidae): analysis of physiological and zootechnical aspects

2018 ◽  
Vol 48 (3) ◽  
pp. 197-206 ◽  
Author(s):  
Arlan de Lima PAZ ◽  
Adalberto Luis VAL
Keyword(s):  
Growth Hormone ◽  
Growth Rate ◽  
Weight Gain ◽  
Hematological Parameters ◽  
Experimental Period ◽  
Daily Weight Gain ◽  
Efficient Production ◽  
Feed Conversion ◽  
Experimental Conditions ◽  
Colossoma Macropomum

ABSTRACT Colossoma macropomum, known locally as tambaqui, is the native fish most farmed in Brazil, however, technological advances are needed to reach efficient production rates. Modulating growth factors, such as growth hormone, may be associated with improved growth rate and feed efficiency. The use of exogenous hormone for fish rearing is prohibited in Brazil, yet the experimental use of bovine hormone can be useful in research aimed at understanding how to stimulate endogenous growth hormones in fish. Therefore, the present study had the strict objective of understanding the effects of growth hormone on the physiology and zootechnical parameters of C. macropomum under experimental conditions. The animals were intraperitoneally injected every fifteen days with 1, 10 and 100 μg g-1 of bGH using 0.9% NaCl saline as diluent. The 10 and 100 μg g-1 bolus had a positive effect on the performance indexes of C. macropomum: weight gain (g), growing length (cm), daily weight gain (g), feed conversion and specific growth rate (% per day). The bGH promoted a greater increase in length than in mass, which caused a reduction in condition factor of the individuals receiving a bolus of 10 and 100 μg g-1. Furthermore, bGH caused no changes in glucose levels, cortisol, hematological parameters, plasma levels of Na+ and K+, and activity of gill’s H+-ATPase and Na+, K+-ATPase, at least during the experimental period considered in the present study.

Relationship between growth rate and undercooling in Pt-added Y1Ba2Cu3O7−x

1996 ◽  
Vol 11 (5) ◽  
pp. 1114-1119 ◽  
Author(s):  
A. Endo ◽  
H. S. Chauhan ◽  
Y. Nakamura ◽  
Y. Shiohara
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Parabolic Equation ◽  
Growth Rates ◽  
Crystal Size ◽  
Experimental Conditions ◽  
Seed Crystals ◽  
Cooling Method ◽  
Increasing Trend ◽  
Good Agreement

Y1Ba2Cu307−x (Y123) crystals were grown by two different methods, the constant undercooling solidification and the continual cooling method, with top seeding by Sm123 seed crystals in order to investigate a relationship between undercooling (ΔT) and a growth rate (R). The crystals of Y123 with a sharp faceted interface, which consisted of {100} and {001} faces, grew epitaxially from the seed. It was found that the growth rates of {100} face (Ra) and that of {001} face (Rc) showed an increasing trend with increasing ΔT, and Rc was faster than Ra within these experimental conditions, ΔT < 20 K. The relation between R and ΔT follows the parabolic equation, viz. Ra ∝ ΔT1.9 and Rc ∝ ΔT1.3 for {100} and {001} faces, respectively. The simulated crystal size using the R and ΔT relations obtained from the constant undercooling method showed good agreement with experimental data by the continual cooling.

Localized Laser-Assisted Deposition of Silicon,Silicon Nitride and Silicon Dioxide

1987 ◽  
Vol 101 ◽  
Author(s):  
Geoffrey Auvert ◽  
Yves Pauleau ◽  
Didier Tonneau
Keyword(s):  
Growth Rate ◽  
Silicon Nitride ◽  
Silicon Dioxide ◽  
Silicon Oxide ◽  
Unsolved Problem ◽  
Experimental Conditions ◽  
Formation Kinetics ◽  
Silicon Based ◽  
Kinetics Of ◽  
Silicon Silicon

ABSTRACTThe localized laser-induced deposition of an insulator for silicon-based microelectronics seems to be an unsolved problem. In order to understand the limiting mechanism in the deposition, the formation kinetics of silicon, silicon oxide and silicon nitride using various laser wavelengths and gas mixtures have been studied Depending upon wavelength and laser-induced temperature, various chemical reactions are involved. In the presence of ammonia, the growth rate of silicon nitride dots was found to be lower than the corresponding silicon deposition rate, indicating that deposition starts with silane decomposition followed by nitridation of silicon. By evaluating the influence of the wavelengths, the existence of a photolytic aided reaction is detected in the presence of 2.4 eV photons. In the presence of oxygen molecules and under most experimental conditions, no deposition occurs. The formation of volatile intermediate compounds can explain the difficulty of locally depositing silicon dioxide.

Water requirements of avocado in Israel. II.* Influence on yield, fruit growth and oil content

1977 ◽  
Vol 28 (5) ◽  
pp. 869 ◽  
Author(s):  
E Lahav ◽  
D Kalmar
Keyword(s):  
Growth Rate ◽  
Coastal Plain ◽  
Oil Content ◽  
Economic Importance ◽  
Harvest Date ◽  
Irrigation Frequency ◽  
Water Requirements ◽  
Experimental Conditions ◽  
Oil Percentage ◽  
Annual Water

The effect of four different irrigation intervals, 7, 14, 21 and 28 days, on the avocado tree was tested during the years 1968–1974 in the northern coastal plain of Israel. The respective average annual water applications were 8890, 7450, 6680 and 5940 m3/ha. The cultivars Ettinger, Fuerte and Hass were tested in five replications in randomized blocks. After 6 years no significant reduction in yield was observed with Ettinger or Fuerte trees irrigated once in 21 or 28 days. With the Hass cultivar the 28-day interval gave lower yields than with the three other intervals tested. Shortening of irrigation intervals increased the growth rate and size of individual fruits, which may be of economic importance for cv. Hass, where overproduction leads to small fruits unsuitable for export. Shortening of irrigation intervals tended to increase the oil percentage of the fruit, which may advance the harvest date. In view of the equal yields obtained and the predominance of cv. Hass in avocado plantations, it was concluded that the 21-day interval was the optimum irrigation frequency under the experimental conditions. __________________ *Part I, Aust. J. Agric. Res., 28: 859 (1977).

First-order parallel and consecutive reaction mechanisms — Isosbestic points criterium

2008 ◽  
Vol 86 (9) ◽  
pp. 918-924 ◽  
Author(s):  
A E Croce
Keyword(s):  
Reaction Mechanism ◽  
Absorption Spectra ◽  
Rate Coefficients ◽  
Isosbestic Point ◽  
Experimental Conditions ◽  
Consecutive Reaction ◽  
Time Resolved ◽  
First Order ◽  
Kinetic Information ◽  
First Case

A criterium for the selection of reaction mechanism derived from a condition for isosbestic points occurrence is presented. Analytical relationships involving the molar absorption coefficients of the species, which participate in a mechanism of parallel first-order reactions and the corresponding rate coefficients, are also reported. A model system of four species that present overlapping absorption spectra may correspond to the reactant and products of a system of parallel or consecutive first-order reactions. In the first case, under experimental conditions in which the absorbances are additive, the presence of an isosbestic point in the spectrum of the reaction mixture at a given wavelength leads to a time-independent ratio of the degree of advancement of reaction variables. From this, relevant kinetic information may be extracted, namely, the ratio of the reaction rate coefficients. Moreover, the occurrence of isosbestic points allows discarding the second mechanism. This conclusion is independent of the number of absorbing species. Model calculated examples show the application of the equations here derived. The resolution for the general case of mechanisms of N first-order reactions is provided.Key words: chemical kinetics, time-resolved absorption spectra, reaction mechanism.

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