Search results for "Process Engineering"
showing 10 items of 931 documents
Chip calorimetry for the monitoring of whole cell biotransformation
2005
Abstract Efficient control of whole cell biotransformation requires quantitative real-time information about the thermodynamics and kinetics of growth and product formation. Heat production contains such information, but its technical application is restricted due to the high price of calorimetric devices, the difficulty of integrating them into existing bioprocesses and the slow response times of established microcalorimeters. A new generation of chip or nanocalorimeters may overcome these weaknesses. We thus tested a highly sensitive chip calorimeter for its applicability in biotechnological monitoring. It was used to monitor aerobic growth of suspended and immobilized Escherichia coli DH…
Variable Step Size P&O Algorithms for Coalescing Pump/Deoiling Hydrocyclone Produced Water Treatment System
2020
This paper presents three variable step size P&O algorithms for optimizing the separation efficiency of a coalescing pump/deoiling hydrocyclone produced water treatment system. By continuously adjusting the pumping pressure, and subsequently the coalescing effect, the algorithms are used to minimize the oil concentration downstream the hydrocyclone. Due to the variable step size, the algorithms react rapidly to changes in the upstream produced water characteristics, at the same time as they reduce (or eliminate) steady-state oscillations. Based on both simulation and experimental testing, the study discusses advantages and disadvantages of the algorithms.
Evolutionary Design Optimization of an Alkaline Water Electrolysis Cell for Hydrogen Production
2020
Hydrogen is an excellent energy source for long-term storage and free of greenhouse gases. However, its high production cost remains an obstacle to its advancement. The two main parameters contributing to the high cost include the cost of electricity and the cost of initial financial investment. It is possible to reduce the latter by the optimization of system design and operation conditions, allowing the reduction of the cell voltage. Because the CAPEX (initial cost divided by total hydrogen production of the electrolyzer) decreases according to current density but the OPEX (operating cost depending on the cell voltage) increases depending on the current density, there exists an optimal cu…
Application of gas separation membranes to detritiation systems
2002
The use of gas separation membranes in tritium removal systems has been studied to develop a new detritiation process. The main advantage of this new process is to reduce the number and/or the size of equipments in comparison to conventional detritiation systems. The objective of this study is to choose the best suited membrane for this application. The hydrogen or its isotopes recovery performance of several commercial hollow fiber organic membranes has been analyzed thanks to three devices. Experiments are performed with small quantities of hydrogen gas or deuterium gas or tritium gas in the range representative of the radioactive contamination level in tritium handling gloveboxes. A math…
Increased oxidative stress is responsible for ether-lipid loss in the retina of senescence accelerated mouse (SAM)
2006
International audience; Purpose: Ether–lipids represent an important class of retinal phospholipids but their exact functions are still unknown. They might act as antioxidants since the vinyl–ether double bond they contain could be the target for newly formed oxygenated radicals. In this work, we investigated the status of ether–lipids and aldehydes, their oxidative degradation products in the retina of a mouse model for aging, the senescence–accelerated mouse prone 8 (SAM P8), in which we reported a reduction of retinal function following 12 months of age (ARVO 2004 E–abstract 797). We completed this study by evaluating the oxidative stress in the retina. Methods: The quantification of eth…
Quantitative colorimetric-imaging analysis of nickel in iron meteorites.
2011
A quantitative analytical imaging approach for determining the nickel content of metallic meteorites is proposed. The approach uses a digital image of a series of standard solutions of the nickel-dimethylglyoxime coloured chelate and a meteorite sample solution subjected to the same treatment as the nickel standards for quantitation. The image is processed with suitable software to assign a colour-dependent numerical value (analytical signal) to each standard. Such a value is directly proportional to the analyte concentration, which facilitates construction of a calibration graph where the value for the unknown sample can be interpolated to calculate the nickel content of the meteorite. The…
Model-based automatic tuning of a filtration control system for submerged anaerobic membrane bioreactors (AnMBR)
2014
This paper describes a model-based method to optimise filtration in submerged AnMBRs. The method is applied to an advanced knowledge-based control system and considers three statistical methods: (1) sensitivity analysis (Morris screening method) to identify an input subset for the advanced controller; (2) Monte Carlo method (trajectory-based random sampling) to find suitable initial values for the control inputs; and (3) optimisation algorithm (performing as a supervisory controller) to re-calibrate these control inputs in order to minimise plant operating costs. The model-based supervisory controller proposed allowed filtration to be optimised with low computational demands (about 5min). E…
A plant-wide energy model for wastewater treatment plants: application to anaerobic membrane bioreactor technology
2016
[EN] The aim of this study is to propose a detailed and comprehensive plant-wide model for assessing the energy demand of different wastewater treatment systems (beyond the traditional activated sludge) in both steady- and unsteady-state conditions. The proposed model makes it possible to calculate power and heat requirements (W and Q, respectively), and to recover both power and heat from methane and hydrogen capture. In order to account for the effect of biological processes on heat requirements, the model has been coupled to the extended version of the BNRM2 plant-wide mathematical model, which is implemented in DESSAS simulation software. Two case studies have been evaluated to assess t…
Exemples de QSAR sur des coefficients de partage
2005
National audience
Image analysis for detecting aggregate gradation in asphalt mixture from planar images
2012
Abstract The mechanical properties of bituminous mixture strongly depend on the gradation of the aggregate that represents the mineral skeleton of the mixture, since for open and gap-graded mixtures, stresses due to vehicles in movement on the pavement are mainly transmitted through their contacts. Internal structure of bituminous mixture is, therefore, of great interest for road and infrastructure engineering and it is appropriate to study it with recently developed image analysis method. The purpose of this study was to finalize an effective analysis of asphalt section image for automatically extracting aggregate gradation without the need of separation of the bitumen from the aggregate. …