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Optimal Process Conditions (optimal + process_condition)
Selected AbstractsApplications of PAT-Process Analytical Technology in Recombinant Protein Processes with Escherichia coliENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2008C. Kaiser Abstract Monitoring of bioprocesses and thus observation and identification of such processes is one of the main aims of bioprocess engineering. It is of vital importance in bioprocess development to improve the overall productivity by avoiding unintentional limitations to ensure not only optimal process conditions but also the observation of established production processes. Furthermore, reproducibility needs to be improved and final product quality and quantity be guaranteed. Therefore, an advanced monitoring and control system has been developed, which is based on different in-line, on-line and at-line measurements for substrates and products. Observation of cell viability applying in-line radio frequency impedance measurement and on-line determination of intracellular recombinant target protein using the reporter protein T-Sapphire GFP based on in-line fluorescence measurement show the ability for the detection of critical process states. In this way, the possibility for the on-line recognition of optimal harvest times arises and disturbances in the scheduled process route can be perceived. [source] Simulation and optimization of supercritical fluid purification of phytosterol estersAICHE JOURNAL, Issue 4 2009Tiziana Fornari Abstract Supercritical carbon dioxide extraction to separate phytosterol esters from fatty acid esters and tocopherols was simulated and optimized using the group contribution equation of state. Experimental extraction data at 328 K, pressures ranging from 200 to 280 bar and solvent-to-feed ratio around 25, was employed to verify the performance of the thermodynamic model. The raw material is the product obtained after a two-step enzymatic reaction carried out on soybean oil deodorizer distillates, and contains mainly fatty-acid ethyl esters, tocopherols and phytosterol esters. The extraction process was simulated using model substances to represent the complex multicomponent feed material. Nonlinear programming techniques were applied to find out optimal process conditions for a steady-state countercurrent process with partial reflux of the extract. The process optimization procedure predicts that a product with 94.2 wt % of phytosterol ester purity and 80% yield could be achieved. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] A NEW APPROACH TO CORRELATE TEXTURAL AND COOKING PARAMETERS WITH OPERATING CONDITIONS DURING DOUBLE-SIDED COOKING OF MEAT PATTIESJOURNAL OF TEXTURE STUDIES, Issue 5 2000SUSANA E. ZORRILLA Cooking and textural parameters during double-sided cooking of hamburger patties were correlated with volume-averaged temperature at the end of the cooking process and gap thickness between plates. Frozen patties were cooked in a clamshell grill set at different plate surface temperatures (177C; 191C; 204C; 218C), for different gap thicknesses (9.65 mm; 10.55 mm; 10.55 mm; 11.05 mm) for 120 s. A decrease in the gap thickness and an increase in the plate surface temperature resulted in an increase in the cooking loss values (24,36%) and in a decrease of press juice values (8,25%). The values of peak load (183,215 N), modulus (16,19 N/mm), work needed in shearing (2300,2800 Nmm), hardness (25,32 N), cohesiveness (0.76,0.83), and chewiness (107,152 Nmm) of the patties increased when the gap thickness decreased and the plate surface temperature increased. There was no effect of the variables studied on springiness. The correlation equations involving the operating variables and quality parameters obtained are simple and useful in developing optimal process conditions. [source] Process optimization of injection molding using an adaptive surrogate model with Gaussian process approachPOLYMER ENGINEERING & SCIENCE, Issue 5 2007Jian Zhou This article presents an integrated, simulation-based optimization procedure that can determine the optimal process conditions for injection molding without user intervention. The idea is to use a nonlinear statistical regression technique and design of computer experiments to establish an adaptive surrogate model with short turn-around time and adequate accuracy for substituting time-consuming computer simulations during system-level optimization. A special surrogate model based on the Gaussian process (GP) approach, which has not been employed previously for injection molding optimization, is introduced. GP is capable of giving both a prediction and an estimate of the confidence (variance) for the prediction simultaneously, thus providing direction as to where additional training samples could be added to improve the surrogate model. While the surrogate model is being established, a hybrid genetic algorithm is employed to evaluate the model to search for the global optimal solutions in a concurrent fashion. The examples presented in this article show that the proposed adaptive optimization procedure helps engineers determine the optimal process conditions more efficiently and effectively. POLYM. ENG. SCI., 47:684,694, 2007. © 2007 Society of Plastics Engineers. [source] Overall numerical simulation of extrusion blow molding processPOLYMER ENGINEERING & SCIENCE, Issue 8 2000Shin-Ichiro Tanifuji This paper focuses on the overall numerical simulation of the parison formation and inflation process of extrusion blow molding. The competing effects due to swell and drawdown in the parison formation process were analyzed by a Lagrangian Eulerian (LE) finite element method (FEM) using an automatic remeshing technique. The parison extruded through an annular die was modeled as an axisymmetric unsteady nonisothermal flow with free surfaces and its viscoelastic properties were described by a K-BKZ integral constitutive equation. An unsteady die-swell simulation was performed to predict the time course of the extrudate parison shape under the influence of gravity and the parison controller. In addition, an unsteady large deformation analysis of the parison inflation process was also carried out using a three-dimensional membrane FEM for viscoelastic material. The inflation sequence for the parison molded into a complex-shaped mold cavity was analyzed. The numerical results were verified using experimental data from each of the sub-processes. The greatest advantage of the overall simulation is that the variation in the parison dimension caused by the swell and drawdown effect can be incorporated into the inflation analysis, and consequently, the accuracy of the numerical prediction can be enhanced. The overall simulation technique provides a rational means to assist the mold design and the determination of the optimal process conditions. [source] Kinetic modeling of a bi-enzymatic system for efficient conversion of lactose to lactobionic acidBIOTECHNOLOGY & BIOENGINEERING, Issue 5 2009Wouter Van Hecke Abstract A model has been developed to describe the interaction between two enzymes and an intermediary redox mediator. In this bi-enzymatic process, the enzyme cellobiose dehydrogenase oxidizes lactose at the C-1 position of the reducing sugar moiety to lactobionolactone, which spontaneously hydrolyzes to lactobionic acid. 2,2,-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt is used as electron acceptor and is continuously regenerated by laccase. Oxygen is the terminal electron acceptor and is fully reduced to water by laccase, a copper-containing oxidase. Oxygen is added to the system by means of bubble-free oxygenation. Using the model, the productivity of the process is investigated by simultaneous solution of the rate equations for varying enzyme quantities and redox mediator concentrations, solved with the aid of a numerical solution. The isocharts developed in this work provide an easy-to-use graphical tool to determine optimal process conditions. The model allows the optimization of the employed activities of the two enzymes and the redox mediator concentration for a given overall oxygen mass transfer coefficient by using the isocharts. Model predictions are well in agreement with the experimental data. Biotechnol. Bioeng. 2009;102: 1475,1482. © 2008 Wiley Periodicals, Inc. [source] | |||||||||||||