scholarly journals STUDY THE GROWTH KINETICS OF PEDIOCOCCUS ACIDILACTICI WITH ESTIMATION OF KINETIC PARAMETERS AND APPLIED IN LARGE SCALE PEDIOCIN PRODUCTION

2016 ◽  
Vol 9 (5) ◽  
pp. 130
Author(s):  
Barnali Mandal
Keyword(s):  
Experimental Data ◽  
Lactic Acid ◽  
Kinetic Parameters ◽  
Growth Kinetics ◽  
Large Scale ◽  
Scale Up ◽  
Small Scale ◽  
Pediococcus Acidilactici ◽  
Monod Model ◽  
Kinetics Of

ABSTRACTObjectives: The aim of the study was to determine the growth kinetics of Pediococcus acidilactici using a mathematical model for large scale pediocinproduction.Methods: Growth kinetics of P. acidilactici has been studied for pediocin production in small scale batch fermenter (Erlenmeyer flask) using meatprocessing waste medium. The experiments have been conducted with varying the concentrations of glucose, protein, and lactic acid. A mathematicalmodel has been developed to describe growth rate, products (pediocin and lactic acid) formation rate, and substrates (glucose and protein) utilizationrate. Monod model for dual substrates (glucose and protein) has been used with considering lactic acid inhibition. Luedeking-Piret model has beenintroduced to describe the production of pediocin and lactic acid.Results: The values of kinetic parameters have been determined using experimental data and model equations. The model prediction has beencompared satisfactorily with the experimental data for the validation of the model.Conclusions: The developed model was satisfactorily validated to scale up the production of pediocin.Keywords: Pediococcus acidilactici, Pediocin, Meat processing waste, Monod model, Luedeking-Piret model, Kinetic parameters.

The Kinetics of Austenization Process of T91 Ferritic Heat-Resistant Steel

2011 ◽  
Vol 317-319 ◽  
pp. 42-47
Author(s):  
Li Fang Zhang ◽  
Yong Chang Liu
Keyword(s):  
Experimental Data ◽  
Phase Transformation ◽  
Kinetic Parameters ◽  
Nucleation And Growth ◽  
Transformation Model ◽  
Resistant Steel ◽  
Kinetic Characteristics ◽  
Heat Resistant Steel ◽  
Austenite Grain ◽  
Kinetics Of

By fitting the calculated transformed fraction according to developed phase-transformation model to the experimental data obtained by differential dilatometry, the kinetic characteristics of the austenitization process in T91 steels have been investigated. According to the kinetic parameters fitted, we recognize that the nucleation and growth of austenite grain are mainly controlled by the diffusion of carbon in ferritic and austenite respectively. In addition, by increasing the diffusion active energy of carbon in austenite, carbides hinder the motion of interface and thus refine austenite grain.

scholarly journals Combined measurement of velocity and temperature in liquid metal convection

2019 ◽  
Vol 876 ◽  
pp. 1108-1128 ◽  
Author(s):  
Till Zürner ◽  
Felix Schindler ◽  
Tobias Vogt ◽  
Sven Eckert ◽  
Jörg Schumacher
Keyword(s):  
Reynolds Number ◽  
Liquid Metal ◽  
Large Scale ◽  
Scale Up ◽  
Convection Cell ◽  
Small Scale ◽  
Convection Flow ◽  
Large Scale Circulation ◽  
Large Scale Flow ◽  
The Impact

Combined measurements of velocity components and temperature in a turbulent Rayleigh–Bénard convection flow at a low Prandtl number of $Pr=0.029$ and Rayleigh numbers of $10^{6}\leqslant Ra\leqslant 6\times 10^{7}$ are conducted in a series of experiments with durations of more than a thousand free-fall time units. Multiple crossing ultrasound beam lines and an array of thermocouples at mid-height allow for a detailed analysis and characterization of the complex three-dimensional dynamics of the single large-scale circulation roll in a cylindrical convection cell of unit aspect ratio which is filled with the liquid metal alloy GaInSn. We measure the internal temporal correlations of the complex large-scale flow and distinguish between short-term oscillations associated with a sloshing motion in the mid-plane as well as varying orientation angles of the velocity close to the top/bottom plates and the slow azimuthal drift of the mean orientation of the roll as a whole that proceeds on a time scale up to a hundred times slower. The coherent large-scale circulation drives a vigorous turbulence in the whole cell that is quantified by direct Reynolds number measurements at different locations in the cell. The velocity increment statistics in the bulk of the cell displays characteristic properties of intermittent small-scale fluid turbulence. We also show that the impact of the symmetry-breaking large-scale flow persists to small-scale velocity fluctuations thus preventing the establishment of fully isotropic turbulence in the cell centre. Reynolds number amplitudes depend sensitively on beam-line position in the cell such that different definitions have to be compared. The global momentum and heat transfer scalings with Rayleigh number are found to agree with those of direct numerical simulations and other laboratory experiments.

Detailed Analysis of the Wake Structure of a Straight-Blade H-Darrieus Wind Turbine by Means of Wind Tunnel Experiments and Computational Fluid Dynamics Simulations

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Alessandro Bianchini ◽  
Francesco Balduzzi ◽  
Giovanni Ferrara ◽  
Lorenzo Ferrari ◽  
Giacomo Persico ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Wind Turbines ◽  
Large Scale ◽  
Vertical Axis ◽  
Performance Estimation ◽  
Small Scale ◽  
Dynamics Simulations

Darrieus vertical axis wind turbines (VAWTs) have been recently identified as the most promising solution for new types of applications, such as small-scale installations in complex terrains or offshore large floating platforms. To improve their efficiencies further and make them competitive with those of conventional horizontal axis wind turbines, a more in depth understanding of the physical phenomena that govern the aerodynamics past a rotating Darrieus turbine is needed. Within this context, computational fluid dynamics (CFD) can play a fundamental role, since it represents the only model able to provide a detailed and comprehensive representation of the flow. Due to the complexity of similar simulations, however, the possibility of having reliable and detailed experimental data to be used as validation test cases is pivotal to tune the numerical tools. In this study, a two-dimensional (2D) unsteady Reynolds-averaged Navier–Stokes (U-RANS) computational model was applied to analyze the wake characteristics on the midplane of a small-size H-shaped Darrieus VAWT. The turbine was tested in a large-scale, open-jet wind tunnel, including both performance and wake measurements. Thanks to the availability of such a unique set of experimental data, systematic comparisons between simulations and experiments were carried out for analyzing the structure of the wake and correlating the main macrostructures of the flow to the local aerodynamic features of the airfoils in cycloidal motion. In general, good agreement on the turbine performance estimation was constantly appreciated.

Research on Pyrolysis Kinetics of Shenhua Coal and Direct Liquefaction Residue

2012 ◽  
Vol 550-553 ◽  
pp. 2758-2762 ◽  
Author(s):  
Xi Jie Chu ◽  
Yong Gang Wang ◽  
Li Hong Zhao
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Coal Pyrolysis ◽  
Pyrolysis Kinetics ◽  
Differential Heating ◽  
Pyrolysis Behavior ◽  
Direct Liquefaction ◽  
Kinetics Of

The pyrolysis tests of Shenhua coal and Shenhua direct liquefaction residue have been carried out using thermogravimetric at the differential heating rate. The kinetic parameters k and E were calculated using DAEM method. Results show DAME model can describe the pyrolysis behavior of Shenhua coal within the range of 20% to 95%, the activation energy of coal pyrolysis ranges from 53.98 to 279.38 kJ/mol, and DAME model can describe the behavior of Shenhua direct liquefaction residue within the range of 10% to 80%, the activation energy of residue pyrolysis is about 170 kJ/mol. The results of which are basically consistent with the experimental data.

Radial Profiles of Particle Velocity in a Large Scale CFB Downer

2004 ◽  
Vol 2 (1) ◽  
Author(s):  
Zhen Qian ◽  
Minghui Zhang ◽  
Hao Yu ◽  
Fei Wei
Keyword(s):  
Particle Velocity ◽  
Large Scale ◽  
Circulating Fluidized Bed ◽  
Scale Up ◽  
Radial Profile ◽  
Small Scale ◽  
Wall Region ◽  
Radial Profiles ◽  
Peak Value ◽  
Near Wall

Radial profiles of particle velocity in a large scale (418 mm I.D.) downward Circulating Fluidized Bed (CFB downer) were obtained via a Laser Doppler Velocimetry (LDV) system. Results show that particle velocity is gradually increasing along the radial direction and there exists a peak value in the near wall region. Such unique radial profile shape can be explained by the solids accumulating trend in the near wall region of the downer. Experiment results in this large scale downer are also compared with those obtained by other researchers in small scale units so as to investigate the scale-up effect on the radial particle velocity distribution in the downer.

Large-Scale Rig for the Characterization of DCC at Sub-Atmospheric Pressure

2020 ◽  
Author(s):  
R. Lo Frano ◽  
A. Pesetti ◽  
D. Aquaro ◽  
M. Olcese
Keyword(s):  
Atmospheric Pressure ◽  
Large Scale ◽  
Fusion Reactor ◽  
Scale Up ◽  
Small Scale ◽  
Vacuum Vessel ◽  
Steam Condensation ◽  
Main Components ◽  
Under Construction ◽  
Experimental Rig

Abstract The Direct Contact Condensation (DCC) is the main phenomenon characterizing the steam condensation. It plays an important role for the operation of Vacuum Vessel Pressure Suppression System (VVPSS) tanks, particularly for managing the Ingress of Coolant Event (determining fusion reactor overpressurization). It is safety relevant (key) system of the fusion reactor because by condensing the steam generated during such accident event allows to damp the overpressure. This paper deals with experimental and theoretical analyses of the DCC at sub-atmospheric pressure. The similitude analysis was elaborated to scale up the experimental results obtained in the reduced scale facility: similitude laws are used for the design of large experimental rig. Correlations are defined starting from the water temperature and pressure variation already obtained in the small-scale rig. Furthermore, the experimental rig and its main components accordingly designed (and under construction at the University of Pisa) allow to study at large scale the steam condensation. The testing conditions are presented and discussed.

scholarly journals Scaling the INGO: What the Development and Expansion of Canadian INGOs Tells Us

2020 ◽  
Vol 9 (8) ◽  
pp. 140
Author(s):  
Logan Cochrane ◽  
John-Michael Davis
Keyword(s):  
Large Scale ◽  
Scale Up ◽  
Critical Factor ◽  
Individual Case ◽  
Government Funding ◽  
Future Research ◽  
Small Scale ◽  
Non Governmental Organizations ◽  
Original Dataset ◽  
Organizational Age

The literature on international non-governmental organizations (INGOs) has focused primarily on large INGOs, which capture the majority of total INGO spending but represent a small number of total INGOs. Over the past two decades, the number of INGOs has more than tripled throughout the global North, which has ushered in a decentralization of the sector as an emerging class of small- and medium-sized INGOs increasingly share the same space once occupied solely by large INGOs. This study focuses on these INGOs in transition to explore how they differ from large INGOs that receive significant government funding and their pathways to scale. Using an original dataset of 1371 Canadian INGOs, we explored comparative differences related to funding sources, overhead, organizational age, country coverage, staff, and religion between the transitioning and small-scale INGOs. Our results identified several general insights for how INGOs transition: (1) Large INGOs are less likely to articulate a religious motivation, which may impede government funding; (2) INGOs are more likely to be headquartered in Ontario, which is closer to federal government offices; (3) low overhead expenditures inhibit small-scale INGOs from transitioning to medium- and large-scale INGOs; (4) organizational age plays a critical factor to scale-up as INGOs increase their experience and expertise; (5) generous compensation to attract talented staff offers an under-valued pathway to scale. Finally, our results demonstrate the diversity among INGOs in Canada and problematizes singular scale-up pathways, while underscoring the necessity of future research to explore scaling strategies through individual case studies.

scholarly journals Gas transfer under breaking waves: experiments and an improved vorticity-based model

2008 ◽  
Vol 26 (8) ◽  
pp. 2131-2142 ◽  
Author(s):  
V. K. Tsoukala ◽  
C. I. Moutzouris
Keyword(s):  
Experimental Data ◽  
Oxygen Transfer ◽  
Large Scale ◽  
Breaking Waves ◽  
Small Scale ◽  
Gas Transfer ◽  
Transfer Coefficients ◽  
Wave Flume ◽  
Proposed Model ◽  
Sloping Beach

Abstract. In the present paper a modified vorticity-based model for gas transfer under breaking waves in the absence of significant wind forcing is presented. A theoretically valid and practically applicable mathematical expression is suggested for the assessment of the oxygen transfer coefficient in the area of wave-breaking. The proposed model is based on the theory of surface renewal that expresses the oxygen transfer coefficient as a function of both the wave vorticity and the Reynolds wave number for breaking waves. Experimental data were collected in wave flumes of various scales: a) small-scale experiments were carried out using both a sloping beach and a rubble-mound breakwater in the wave flume of the Laboratory of Harbor Works, NTUA, Greece; b) large-scale experiments were carried out with a sloping beach in the wind-wave flume of Delft Hydraulics, the Netherlands, and with a three-layer rubble mound breakwater in the Schneideberg Wave Flume of the Franzius Institute, University of Hannover, Germany. The experimental data acquired from both the small- and large-scale experiments were in good agreement with the proposed model. Although the apparent transfer coefficients from the large-scale experiments were lower than those determined from the small-scale experiments, the actual oxygen transfer coefficients, as calculated using a discretized form of the transport equation, are in the same order of magnitude for both the small- and large-scale experiments. The validity of the proposed model is compared to experimental results from other researchers. Although the results are encouraging, additional research is needed, to incorporate the influence of bubble mediated gas exchange, before these results are used for an environmental friendly design of harbor works, or for projects involving waste disposal at sea.

scholarly journals Unsteady aerodynamic analysis for offshore floating wind turbines under different wind conditions

2015 ◽  
Vol 373 (2035) ◽  
pp. 20140080 ◽  
Author(s):  
B. F. Xu ◽  
T. G. Wang ◽  
Y. Yuan ◽  
J. F. Cao
Keyword(s):  
Experimental Data ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Large Scale ◽  
Aerodynamic Performance ◽  
Small Scale ◽  
Floating Platform ◽  
Unsteady Aerodynamic ◽  
Blade Root ◽  
Platform Motions

A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip.

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