scholarly journals On the theoretical prediction of microalgae growth for parallel flow

2020 ◽  
Author(s):  
Chunyang Ma
Keyword(s):  
Growth Rate ◽  
Growth Models ◽  
Concentration Field ◽  
Parallel Flow ◽  
Biofuel Production ◽  
Order Of Magnitude ◽  
Growth Problem ◽  
Semi Empirical ◽  
First Time ◽  
Microalgae Growth

Abstract Background: The established microalgae growth models are semi-empirical or considerable fitting coefficients exist. Therefore, the ability of the model prediction is reduced by the numerous fitting coefficients. Furthermore, the predicted results of the established models are dependent on the size of the photobioreactor (PBR), light intensity, flow and concentration field. The growth mechanism of microalgae has not clearly understood in PBR cultivation. It is difficult to predict the microalgae growth by theoretical methods, owing to the aforementioned factors. We developed an exploratory bridging microalgae growth model to predict the microalgae growth rate in PBRs by using the nondimensional method which is effectively in fluid dynamics and heat transfer.Results: The analytical solution of the growth rate was obtained for the parallel flow. The nondimensional growth rate expressed as function of Reynolds number and Schmidt number, which can be used for arbitrary parallel flow due to the solution was expressed as nondimensional quantities. The theoretically predicted growth rate is compared with the experimentally measured microalgae growth rate on the order of magnitude.Conclusions: The nondimensional method successfully applied to the microalgae growth problem for the first time. The general nondimensional solution can unify the numerous experimental data for different laboratory conditions, and give a direction for the disorder of the microalgae growth problem. The nondimensional solution will be useful in the design and operation of PBRs for biofuel production.

scholarly journals On the theoretical prediction of microalgae growth for parallel flow

2020 ◽  
Author(s):  
Chunyang Ma
Keyword(s):  
Growth Rate ◽  
Growth Models ◽  
Concentration Field ◽  
Parallel Flow ◽  
Biofuel Production ◽  
Order Of Magnitude ◽  
Growth Problem ◽  
Semi Empirical ◽  
First Time ◽  
Microalgae Growth

Abstract Background: The established microalgae growth models are semi-empirical or considerable fitting coefficients exist. Therefore, the ability of the model prediction is reduced by the numerous fitting coefficients. Furthermore, the predicted results of the established models are dependent on the size of the photobioreactor (PBR), light intensity, flow and concentration field. The growth mechanism of microalgae has not clearly understood in PBR cultivation. It is difficult to predict the microalgae growth by theoretical methods, owing to the aforementioned factors. We developed an exploratory bridging microalgae growth model to predict the microalgae growth rate in PBRs by using the nondimensional method which is effectively in fluid dynamics and heat transfer. Results: The analytical solution of the growth rate was obtained for the parallel flow. The nondimensional growth rate expressed as function of Reynolds number and Schmidt number, which can be used for arbitrary parallel flow due to the solution was expressed as nondimensional quantities. The theoretically predicted growth rate is compared with the experimentally measured microalgae growth rate on the order of magnitude. Conclusions: The nondimensional method successfully applied to the microalgae growth problem for the first time. The general nondimensional solution can unify the numerous experimental data for different laboratory conditions, and give a direction for the disorder of the microalgae growth problem. The nondimensional solution will be useful in the design and operation of PBRs for biofuel production.

scholarly journals PHAEODACTYLUM TRICORNUTUM MICROALGAE GROWTH RATE IN HETEROTROPHIC AND MIXOTROPHIC CONDITIONS

2009 ◽  
Vol 8 (1) ◽  
pp. 84 ◽  
Author(s):  
K. C. C. Morais ◽  
R. L. L. Ribeiro ◽  
K. R. Santos ◽  
D. M. Taher ◽  
A. B. Mariano ◽  
...  
Keyword(s):  
Growth Rate ◽  
Phaeodactylum Tricornutum ◽  
Agricultural Land ◽  
Production Costs ◽  
Biofuel Production ◽  
Glycerol Concentration ◽  
Microalgae Biomass ◽  
Dry Biomass ◽  
Number Of Cells ◽  
Microalgae Growth

The Brazilian National Program for Biofuel Production has been encouraging diversification of feedstock for biofuel production. One of the most promising alternatives is the use of microalgae biomass for biofuel production. The cultivation of microalgae is conducted in aquatic systems, therefore microalgae oil production does not compete with agricultural land. Microalgae have greater photosynthetic efficiency than higher plants and are efficient fixing CO2. The challenge is to reduce production costs, which can be minimized by increasing productivity and oil biomass. Aiming to increase the production of microalgae biomass, mixotrophic cultivation, with the addition of glycerol has been shown to be very promising. During the production of biodiesel from microalgae there is availability of glycerol as a side product of the transesterification reaction, which could be used as organic carbon source for microalgae mixotrophic growth, resulting in increased biomass productivity. In this paper, to study the effect of glycerol in experimental conditions, the batch culture of the diatom Phaeodactylum tricornutum was performed in a 2-liter flask in a temperature and light intensity controlled room. During 16 days of cultivation, the number of cells per ml was counted periodically in a Neubauer chamber. The calculation of dry biomass in the control experiment (without glycerol) was performed every two days by vacuum filtration. In the dry biomass mixotrophic experiment with glycerol concentration of 1.5 M, the number of cells was assessed similarly in the 10th and 14th days of cultivation. Through a volume element methodology, a mathematical model was written to calculate the microalgae growth rate. Was used an equation that describes the influence of irradiation and concentration of nutrients in the growth of microalgae. A simulation time of 16 days was used in the computations, with initial concentration of 0.1 g l-1. In order to compare simulation data with experimental data, we calculated the dry weight in 8 points in the course of sixteen days. In this way, it was possible to assess graphically biomass concentration versus time through the experiments and by numerical simulation. It was identified that the simulation results were consistent with the experiments and that the addition of glycerol greatly influenced the growth of microalgae. In the present analysis, the glycerol added increased 30% in biomass.

TOWARDS THE QUESTION OF SPECIALIZED FEEDS FOR TENCHES (TINCA TINCA)

2017 ◽  
pp. 89-97
Author(s):  
Elena Mikhaylovna Chervonenko ◽  
Lina Yurievna Lagutkina
Keyword(s):  
Growth Rate ◽  
Fish Growth ◽  
Animal Origin ◽  
State Technical ◽  
Tinca Tinca ◽  
Daily Growth ◽  
Volga River ◽  
The Moment ◽  
First Time ◽  
Technical Centre

The article describes the process of tench growing (male and female species removed from set gear in the Volga river in the Astrakhan region) using experimental feedstuff "T", taking into account the fact that problems with artificial growing tench ( Тinca tinca ) appear first in the process of feeding when wild sires change to artificial food. The research took place on the base of the department of aquaculture and water bioresources of Astrakhan State Technical University in innovation centre "Bioaquapark - scientific and technical centre of aquaculture" in 2015. Special feed including components of animal origin - mosquito grab and sludge worm as an effective substitute to fish flour, as well as components of vegetable origin (carrot, parsley, pumpkin, wheatgrass) for domestication of tenches are offered for the first time. Food technology has been described. The exact composition of the formula, which is being licensed at the moment, is not disclosed. Feed "T", which has undergone biological analysis and is in accordance with organoleptic and physical standards was used for feeding tench female and male species during domestication period (60 days), along with food "Coppens" (Holland). Feed efficiency was determined according to survival and daily fish growth. Growth rate of females appeared more intensive than growth rate of males fed with experimental food "T". Daily growth changed depending on the types of food: from 0.3 ("Coppens") to 0.47 (experimental food) in females, from 0.25 ("Coppens") to 0.39 (experimental food) with males. Ability to survive among tench species fed with "Coppens" and experimental food made 60% and 100%, correspondingly. Nutricion of tench species with experimental food encouraged their domestication, which allowed using tench species in further fish breeding process in order to get offspring. The project was supported by the Innovation Promotion Fund in terms of the project "Development and implementation of the technique for the steady development of aquaculture: food "TechSA".

Detection and Quantification of 7-Hydroxydehydroepiandrosterone Epimers in Three Body Fluids

2002 ◽  
Vol 67 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Richard Hampl ◽  
Martin Hill ◽  
Luboslav Stárka
Keyword(s):  
Healthy Subjects ◽  
Serum Levels ◽  
Body Fluids ◽  
Gas Chromatography Mass Spectrometry ◽  
Specific Radioimmunoassay ◽  
Order Of Magnitude ◽  
Three Body ◽  
First Time ◽  
Nanomolar Range ◽  
Detection And Quantification

3β,7α-Dihydroxyandrost-5-en-17-one (1) (7α-OH-DHEA) and its 7β-hydroxy epimer 2 (7β-OH-DHEA) - 7α- and 7β-hydroxydehydroepiandrosterone - were detected and quantified in three human body fluids: in blood serum, saliva and ejaculate. Specific radioimmunoassay and gas chromatography-mass spectrometry have been used. For the first time the data on changes of these dehydroepiandrosterone metabolites are reported for a representative group of healthy subjects of both sexes (172 females and 217 males) during the life span. The serum levels of both 7-hydroxydehydroepiandrosterone epimers in serum and also in semen were in the low nanomolar range, while concentrations by one order of magnitude lower were found in saliva, but still within the detection limit. The results will serve as a basis for comparative studies of 7-hydroxydehydroepiandrosterone levels under various pathophysiological conditions, with a particular respect to autoimmune disorders.

scholarly journals Evolutionary economics: Crisis, transformation and metamorphosis

2021 ◽  
pp. 1-8
Author(s):  
Milan Zeleny
Keyword(s):  
Growth Rate ◽  
Productivity Growth ◽  
Driving Force ◽  
Evolutionary Economics ◽  
Regional Economies ◽  
Economic Evolution ◽  
Economic Sectors ◽  
Advanced Economies ◽  
First Time

Most world economies are undergoing fundamental transformations of economic sectors, shifting their employed workforce through the secular sequence of (1. Agriculture⟶2. Industry⟶3. Services⟶4. Government). The productivity growth rate is the driving force. Most advanced economies have reached the final stages of the sequence. Assorted recessions, crises and stagnations are simply cofluent, accompanying phenomena. Crises might be cyclical, but economic evolution is unidirectional. Traditional economics can hardly distinguish phenomena of crisis from those of the transformation. Because there is no “fifth sector”, some economies are entering the phase of metamorphosis, for the first time in history. Metamorphosis is manifested through deglobalization, relocalization and autonomization of local and regional economies. We are entering the Age of Entrepreneurship.

Enhancement of Hydrocarbon Productivity of Botryococcus braunii by an Adenine Type Phytohormone

2012 ◽  
Vol 512-515 ◽  
pp. 397-400
Author(s):  
Jun Zhi Liu ◽  
Ya Ming Ge ◽  
Guang Ming Tian
Keyword(s):  
Growth Rate ◽  
Low Dose ◽  
Algal Growth ◽  
Botryococcus Braunii ◽  
Biofuel Production ◽  
Carotenoid Content ◽  
Algae Biofuels ◽  
Hydrocarbon Content ◽  
Algal Growth Rate ◽  
Hydrocarbon Productivity

This study examined the effects of an adenine-type cytokinin 6-benzylaminopurine (6-BA) on the growth and metabolism characteristics of Botryococcus braunii, one of the most promising oil-rich algae for biofuel production. The results showed that 6-BA of low dose (0.1-1.0 mg L-1) would enhance the algal growth rate and biochemical synthesis, whereas too much (5.0 mg L-1) would be lethally toxic for B. braunii. Noticingly, though the maximum algal growth rate, chlorophyll and β-carotenoid content were observed in the treatment with 0.5 and/or 1.0 mg L-1 6-BA, both the maximum algal hydrocarbon content and the highest hydrocarbon productivity were observed in the treatment with 0.1 mg L-1 6-BA, which were respectively 2.45 and 3.48 times of the control (39.1% vs. 16.0%, 546 mg L-1 vs. 157 mg L-1). This finding has great implications for improving algae biofuels production by phytohormone.

Ultra-Low Resistance Ni-Based Contacts to n-InP: the Dependence of Contact Resistivity on the Condition of the Metal-Semiconductor Interface

1993 ◽  
Vol 318 ◽  
Author(s):  
Navid S. Fatemi ◽  
Victor G. Weizer
Keyword(s):  
Deposition Process ◽  
Atomic Ratio ◽  
Contact Resistivity ◽  
Semiconductor Interface ◽  
Near Surface ◽  
Process Use ◽  
Fold Reduction ◽  
Specific Contact ◽  
Order Of Magnitude ◽  
First Time

ABSTRACTNear-theoretical-minimum values of specific contact resistivity, ρc (in the mid-to-low E-8 Ω-cm2 range) have been achieved for Ni-based contacts to moderately doped (2E18 cm−3) n-type InP. In each case these values are an order of magnitude lower than those previously achieved. These ultra-low resistivities are shown to result when the metallurgical interaction rate between the contact metal and the semiconductor is sufficiently reduced. Several methods of reducing the metal-InP reaction rate and thus achieving lowered resistivity values are demonstrated. We show, for instance, that the introduction of a thin (100Å) Au layer at the metal-InP interface retards metal-semiconductor intermixing during sintering and results in a ten-fold reduction in pc. Another method consists of ensuring the perfection of the near-surface InP lattice prior to and during contact deposition process. Use of this technique has enabled us to fabricate, for the first time, Ni-only contacts with pc values in the low E-8 Ω-cm2 range. We present an explanation for these observations that is based upon the magnitude of the In-to-P atomic ratio at the metal-InP interface.

A population birth-and-mutation process, I: explicit distributions for the number of mutants in an old culture of bacteria

1974 ◽  
Vol 11 (03) ◽  
pp. 437-444 ◽  
Author(s):  
Benoit Mandelbrot
Keyword(s):  
Growth Rate ◽  
Mutation Rate ◽  
Growth Rates ◽  
Random Variable ◽  
Mutation Process ◽  
Limit Condition ◽  
Rate Of Growth ◽  
Mathematical Techniques ◽  
First Time

Luria and Delbrück (1943) have observed that, in old cultures of bacteria that have mutated at random, the distribution of the number of mutants is extremely long-tailed. In this note, this distribution will be derived (for the first time) exactly and explicitly. The rates of mutation will be allowed to be either positive or infinitesimal, and the rate of growth for mutants will be allowed to be either equal, greater or smaller than for non-mutants. Under the realistic limit condition of a very low mutation rate, the number of mutants is shown to be a stable-Lévy (sometimes called “Pareto Lévy”) random variable, of maximum skewness ß, whose exponent α is essentially the ratio of the growth rates of non-mutants and of mutants. Thus, the probability of the number of mutants exceeding the very large value m is proportional to m –α–1 (a behavior sometimes referred to as “asymptotically Paretian” or “hyperbolic”). The unequal growth rate cases α ≠ 1 are solved for the first time. In the α = 1 case, a result of Lea and Coulson is rederived, interpreted, and generalized. Various paradoxes involving divergent moments that were encountered in earlier approaches are either absent or fully explainable. The mathematical techniques used being standard, they will not be described in detail, so this note will be primarily a collection of results. However, the justification for deriving them lies in their use in biology, and the mathematically unexperienced biologists may be unfamiliar with the tools used. They may wish for more details of calculations, more explanations and Figures. To satisfy their needs, a report available from the author upon request has been prepared. It will be referred to as Part II.

Rapid Thermal Oxidation of Lightly Doped Silicon in N2O

1994 ◽  
Vol 342 ◽  
Author(s):  
S.C. Sun ◽  
L.S. Wang ◽  
F.L. Yeh ◽  
T.S. Lai ◽  
Y.H. Lin
Keyword(s):  
Growth Rate ◽  
Thermal Oxidation ◽  
Charge Trapping ◽  
Interface State ◽  
Constant Current ◽  
Mos Capacitor ◽  
Rapid Thermal Oxidation ◽  
Doped Silicon ◽  
State Generation ◽  
First Time

ABSTRACTIn this paper, a detailed study is presented for the growth kinetics of rapid thermal oxidation of lightly-doped silicon in N2O and O2 on (100), (110), and (111) oriented substrates. It was found that (110)-oriented Si has the highest growth rate in both N2O and dry O2, and (100) Si has the lowest rate. There is no “crossover” on the growth rate of rapid thermal N2O oxidation between (110) Si and (111) Si as compared to oxides grown in furnace N2O. Pressure dependence of rapid thermal N2O oxidation is reported for the first time. MOS capacitor results show that the low-pressure (40 Torr) N2O-grown oxides have much less interface state generation and charge trapping under constant current stress as compared to oxides grown in either 760 Torr N2O or O2 ambient.

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