Modeling response of nitrifying biofilm to inhibitory shock loads

2004 ◽  
Vol 50 (6) ◽  
pp. 53-60 ◽  
Author(s):  
B.K. Rajbhandari ◽  
A.P. Annachhatre
Keyword(s):  
Experimental Observation ◽  
Exposure Time ◽  
Close Agreement ◽  
Nitrate Concentration ◽  
Recovery Phase ◽  
Biofilm Reactor ◽  
Experimental Results ◽  
Ambient Conditions ◽  
Shock Loads ◽  
Inhibitory Compound

To study the response of nitrifying biofilm to inhibitory shock loads, a lab-scale nitrifying biofilm reactor was operated in ambient conditions. Shock loads of various concentrations of inhibitory compound were applied to the biofilm. Aniline was used as an inhibitory compound. The experimental results were utilized to develop a model for predicting the variation of effluent nitrate concentration from the biofilm reactor for given shock loads of aniline concentration and exposure time both in exposure as well as in recovery phase. Close agreement between model and experimental observation of bulk aniline concentration and effluent nitrate concentration was obtained which indicates the usefulness of the model to estimate bulk aniline concentration and to predict the response of inhibitory shock loads on nitrifying biofilm.

scholarly journals Denitrification Kinetics of Nitrate by a Heterotrophic Culture in Batch and Fixed-Biofilm Reactors

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 547
Author(s):  
Yen-Hui Lin ◽  
Yi-Jie Gu
Keyword(s):  
Continuous Flow ◽  
Nitrate Concentration ◽  
Batch Reactor ◽  
Nitrate Removal ◽  
Biofilm Reactor ◽  
Experimental Results ◽  
Heterotrophic Culture ◽  
Concentration Data ◽  
Water And Wastewater Treatment ◽  
Fixed Biofilm

Herein, the progress of nitrate removal by a heterotrophic culture in a batch reactor and continuous-flow fixed-biofilm reactor was examined. Two batch experiments for nitrate reduction with acetate degradation using 250 mL batch reactors with acclimated denitrifying biomass were conducted. The experimental results indicated that the nitrate was completely reduced; however, the acetate remained at a concentration of 280 mg/L from initial nitrate concentration of 100 mg/L. However, the acetate was fully biodegraded by the denitrifying biomass at an initial nitrate concentration of 300 mg/L. To evaluate the biokinetic parameters, the concentration data of nitrate, nitrite, acetate, and denitrifying biomass from the batch kinetic experiments were compared with those of the batch kinetic model system. A continuous-flow fixed-biofilm reactor was used to verify the kinetic biofilm model. The removal efficiency of nitrate in the fixed-biofilm reactor at the steady state was 98.4% accompanied with 90.5% acetate consumption. The experimental results agreed satisfactorily with the model predictions. The modeling and experimental approaches used in this study could be applied in the design of a pilot-scale, or full-scale, fixed-biofilm reactor for nitrate removal in water and wastewater treatment plants.

scholarly journals Calculation of loading-induced tendon slip in beams prestressed with external tendons. Part II: Numerical analysis

2006 ◽  
Vol 28 (4) ◽  
pp. 207-218
Author(s):  
Bui Khac Diep ◽  
Lam Huu Quang
Keyword(s):  
Numerical Analysis ◽  
Experimental Observation ◽  
Equilibrium Condition ◽  
Close Agreement ◽  
Applied Load ◽  
Experimental Results ◽  
External Tendons ◽  
Computing Method ◽  
As Effects ◽  
Force Equilibrium

In this paper, a computing method for the tendon slip based on the force equilibrium condition at deviators was proposed. The proposed method for the evaluation of tendon slip was presented in a general form by taking into account all possibilities of tendon slip at deviators, and several factors found to be important that affect the tendon slip, such as effects of the slippage at two adjacent deviators, friction, change of tendon angles during the applied load, etc. The validation of the proposed method was verified by comparing with the experimental results. The predicted results showed a close agreement with the experimental observation.

Constitutive modeling for the mechanical behavior of rubber with filler particles

2021 ◽  
Author(s):  
Sankalp Gour ◽  
Deepu Kumar Singh ◽  
Deepak Kumar ◽  
Vinod Yadav
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Mechanical Behavior ◽  
Experimental Observation ◽  
Continuum Mechanics ◽  
Constitutive Modeling ◽  
Carbon Nanoparticles ◽  
Material Behavior ◽  
Experimental Results ◽  
Filler Particles

Abstract The present study deals with the constitutive modeling for the mechanical behavior of rubber with filler particles. An analytical model is developed to predict the mechanical properties of rubber with added filler particles based on experimental observation. To develop the same, a continuum mechanics-based hyperelasticity theory is utilized. The model is validated with the experimental results of the chloroprene and nitrile butadiene rubbers filled with different volume fractions of carbon black and carbon nanoparticles, respectively. The findings of the model agree well with the experimental results. In general, the developed model will be helpful to the materialist community working in characterizing the material behavior of tires and other rubber-like materials.

The Strength of Thick-Walled Cylinders

1959 ◽  
Vol 81 (2) ◽  
pp. 95-111 ◽  
Author(s):  
B. Crossland ◽  
S. M. Jorgensen ◽  
J. A. Bones
Keyword(s):  
Shear Stress ◽  
Mild Steel ◽  
Close Agreement ◽  
Large Strain ◽  
Tension Test ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Strain Behavior ◽  
Pressure Tests ◽  
Strain Data

Comprehensive pressure tests have been carried out on thick-walled, closed-ended cylinders made from a mild steel and a hardened and tempered steel, the maximum pressure reached being 94,000 lb/in.2 The complete theoretical behavior of the cylinders is computed from shear stress-strain data obtained from torsion tests and is shown to be in very close agreement with the experimental results. In addition, a method is given for deriving the large strain behavior of the cylinders from tension test data. When compared with the experimental results this approach gives larger errors, the theoretical values of pressure being consistently high. Finally, ultimate pressures have been calculated from two empirical expressions.

scholarly journals THE MOTIONS OF A MOORED SHIP IN A HARBOR BASIN

1982 ◽  
Vol 1 (18) ◽  
pp. 165 ◽  
Author(s):  
T. Sawaragi ◽  
M. Kubo
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Close Agreement ◽  
Three Dimensional ◽  
Ship Motion ◽  
Experimental Results ◽  
New Methods

In harbors affected by ocean swells,cargo handlings are often interrupted and irooring lines are broken as a result of severe ship motionsl). In order to decrease such accidents, the noored ship notions in a harbor basin must be studied. In this paper the ship notions in the harbor basin are investigated by using three dimensional Green's function and close agreement between theoretical and experimental results can be found. New methods to reduce noored ship motion are also proposed. The efficiency of these methods is verified theoretically and experimentally.

scholarly journals Experimental Observation Of Nonlinear Vibrations Using A Closed-Loop Vibration System

2015 ◽  
Vol 22 (4) ◽  
pp. 559-564 ◽  
Author(s):  
Everaldo de Barros ◽  
Carlos d’Andrade Souto ◽  
Mauro Hugo Mathias
Keyword(s):  
Experimental Observation ◽  
Nonlinear Vibrations ◽  
Closed Loop ◽  
Response Spectrum ◽  
Excitation Frequency ◽  
Excitation Amplitude ◽  
Experimental Results ◽  
Vibration System ◽  
Response Curves ◽  
Flexural Mode

Abstract This paper presents experimental observation of nonlinear vibrations in the response of a flexible cantilever beam to transverse harmonic base excitations around its flexural mode frequencies. In the experimental setup, instead of manual control of the signal excitation frequency and amplitude, a closed-loop vibration system is used to keep the excitation amplitude constant during the frequency sweep and to increase confidence in the experimental results. The experimental results show the presence of the third mode in the response when varying the excitation frequency around the fourth mode. The frequency-response curves, response spectrum and Poincaré plots were used for characterization of nonlinear dynamic behaviour of the beam.

scholarly journals Experimental Analysis and Modeling of Nitrate Removal through Zero-Valent Magnesium Particles

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1276 ◽  
Author(s):  
Siciliano ◽  
Curcio ◽  
Limonti
Keyword(s):  
Nitrate Concentration ◽  
Nitrate Removal ◽  
Experimental Results ◽  
Process Efficiency ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Nitrogen Forms ◽  
Sustainable Technologies ◽  
Batch Tests ◽  
Effects Of Ph

The pollution of water by nitrates represents an important environmental and health issue. The development of sustainable technologies that are able to efficiently remove this contaminant is a key challenge in the field of wastewater treatment. Chemical denitrification by means of zero-valent metallic elements is an interesting method to reduce the oxidized forms of nitrogen. Compared to other metallic reactants, zero-valent magnesium (ZVM) has many profitable aspects, but its use for nitrate removal has scarcely been investigated. In the present work, several batch tests were conducted to examine the concurrent effects of pH, initial nitrate concentration and Mg0 quantity on process performance. The experimental results proved that at pH 3, for a given initial nitrate concentration, the dose of ZVM largely influences process efficiency. In particular, with a ratio between Mg0 and initial N-NO3− amount (Mg/NNi) of 0.33 g/mg, it is possible to obtain complete denitrification within 30 min. Beyond this ratio, no further improvement of treatment was observed. The experiments allowed us to identify the nitrogen forms produced during the treatment. Nitrogen gas was generally the main reaction product, but the trends of the different compounds (NO3−, NO2−, NH4+ and N2) notably changed in response to the modification of operating parameters. Moreover, the results demonstrated that, in a highly acidic environment, when treating solutions with a low nitrate concentration, process performances are unsatisfactory even when using a high Mg/NNi ratio. By increasing the process pH to 5 and 7, a significant denitrification decline occurred. Furthermore, at these pH levels, the enhancement of nitrate concentration caused a progressive process deterioration. Through detailed analysis of experimental results, reactions kinetics and new mathematical equations, able to describe the trends of different nitrogen forms, have been defined. Moreover, reactions pathways have been proposed. Finally, the characterization of exhausted material allowed us to identify the corrosion products formed during the treatment.

scholarly journals Artificial Neural Network (ANN) Modeling for Prediction of Pesticide Wastewater Degradation by FeGAC/H2O2 Process

2018 ◽  
Vol 65 ◽  
pp. 05004
Author(s):  
Augustine Chioma Affam ◽  
Malay Chaudhuri ◽  
Chee Chung Wong ◽  
Chee Swee Wong
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Close Agreement ◽  
Transfer Functions ◽  
Cod Removal ◽  
Experimental Results ◽  
Ann Model ◽  
Ann Modeling ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

The study examined artificial neural network (ANN) modeling for the prediction of chlorpyrifos, cypermethrin and chlorothalonil pesticides degradation by the FeGAC/H2O2 process. The operating condition was the optimum condition from a series of experiments. Under these conditions; FeGAC 5 g/L, H2O2 concentration 100 mg/L, pH 3 and 60 min reaction time, the COD removal obtained was 96.19%. The ANN model was developed using a three-layer multilayer perceptron (MLP) neural network to predict pesticide degradation in terms of COD removal. The configuration of the model with the smallest mean square error (MSE) of 0.000046 contained 5 inputs, 9 hidden and, 1 output neuron. The Levenberg–Marquardt backpropagation training algorithm was used for training the network, while tangent sigmoid and linear transfer functions were used at the hidden and output neurons, respectively. The predicted results were in close agreement with the experimental results with correlation coefficient (R2) of 0.9994 i.e. 99.94% showing a close agreement to the actual experimental results. The sensitivity analysis showed that FeGAC dose had the highest influence with relative importance of 25.33%. The results show how robust the ANN model could be in the prediction of the behavior of the FeGAC/H2O2 process.

scholarly journals Effect of exposure time ratio on Intermittent Aerated Moving Bed Biofilm Reactor

2020 ◽  
Vol 167 ◽  
pp. 01008
Author(s):  
He Wang ◽  
Hui-qiang Li
Keyword(s):  
Exposure Time ◽  
Phosphorus Removal ◽  
Biofilm Reactor ◽  
Moving Bed Biofilm Reactor ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Time Ratio ◽  
Do Concentration ◽  
Biofilm Process ◽  
Biological Nitrogen

This study combined the IA craft, and the goal is to achieve aerobic, anoxic and even anaerobic alternating cycles in the same reactor to enhance biological nitrogen and phosphorus removal. At present, there are many studies on the IA process, but less research on the IAMBBR craft. The IAMBBR craft combines intermittent aeration with a biofilm process, which can further improve the processing capacity of a continuous-flow biofilm reactor. Therefore, it is necessary to conduct a detailed study of the IAMBBR craft. In addition, the exposure time ratio is an important parameter for the operation of the IA craft. By adjusting the exposure time ratio, the DO concentration in the reactor can be controlled, which affects the operation effect of the reactor. Therefore, this chapter mainly explores the effect of exposure time ratio on the operating effect of IAMBBR. Six operating stages were connected: the ratio of CA and exposure time are 3h/3h, 1h/1h, 30min/30min, 15min/15min, and 5min/5min, respectively, to study the removal effect of pollutants.

The dynamics of infection of Tribolium confusum by Hymenolepis diminuta: the influence of exposure time and host density

Parasitology ◽  
1982 ◽  
Vol 84 (1) ◽  
pp. 157-166 ◽  
Author(s):  
Anne Keymer
Keyword(s):  
Exposure Time ◽  
Parasite Burden ◽  
Host Density ◽  
Faecal Pellet ◽  
Experimental Results ◽  
Hymenolepis Diminuta ◽  
Parasite Transmission ◽  
Experimental Conditions ◽  
Instantaneous Rate ◽  
The Mean

SUMMARYSurvival of Hymenolepis diminuta eggs (as measured by their infectivity to the intermediate host) was found to be age-dependent with an expected value of 11 days when the eggs were retained within the faecal pellet at 10 °C. The expected life-span of eggs under experimental conditions (i.e. extracted from faecal material and placed on filter paper at 30 °C) was estimated as 33 min. The mean parasite burden of populations of Tribolium exposed to known densities of H. diminuta eggs was found to rise to a plateau with increasing exposure time. The experimental results provided a method of estimating the instantaneous rate of parasite transmission: a value of 0·0004/egg/min/host/13 cm2 was obtained. The mean parasite burden of populations of T. confusum exposed to known densities of H. diminuta eggs was found to decrease exponentially with increasing host density. A second estimate of the instantaneous rate of parasite transmission of 0·004/egg/min/host/13 cm2 was obtained from the experimental results. No differences in susceptibility to infection between 2-week-old male and female beetles were found. A marked decrease, however, was apparent with increasing beetle age up to 14 weeks post-eclosion.

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