Search results for "Continuous"
showing 10 items of 899 documents
Photocatalytic degradation of 4-nitrophenol in a continuous reactor containing titanium dioxide supported on glass beads
2008
WOS: 000258975200009
Control of a Non-isothermal CSTR by Type-2 Fuzzy Logic Controllers
2009
The paper describes the application of a type-2 fuzzy logic controller (FLC) to a non-isothermal continuous stirred tank reactor (CSTR) characterized by the presence of saddle node and Hopf bifurcations. Its performance is compared with a type-1 fuzzy logic controller performance. A full analysis of the uncontrolled CSTR dynamic was carried out and used for the feedback-feedforward fuzzy controllers development. Simulation results confirm the effectiveness and the robustness of the type-2 FLCs which outperform their type-1 counterparts, particularly when uncertainties are present in the system.
An integrated approach for the HCl and metals recovery from waste pickling solutions: pilot plant and design operations
2021
Abstract Continuous regeneration of industrial pickling solutions and recovery of valuable materials are implemented in a pilot-scale plant including diffusion dialysis (DD), where HCl is recovered, membrane distillation (MD), where HCl is concentrated, and reactive precipitation (CSTR), where metal ions are recovered in different forms. The integration of the three processes allows to minimize waste streams generation and to accomplish a closed-loop process, thus increasing the environmental sustainability and economic impact of the galvanizing industry. Process reliability was proved through the operation of a demonstrator in the real industrial environment of the Tecnozinco SrL hot-dip g…
Control of a non-isothermal continuous stirred tank reactor by a feedback–feedforward structure using type-2 fuzzy logic controllers
2011
A control system that uses type-2 fuzzy logic controllers (FLC) is proposed for the control of a non-isothermal continuous stirred tank reactor (CSTR), where a first order irreversible reaction occurs and that is characterized by the presence of bifurcations. Bifurcations due to parameter variations can bring the reactor to instability or create new working conditions which although stable are unacceptable. An extensive analysis of the uncontrolled CSTR dynamics was carried out and used for the choice of the control configuration and the development of controllers. In addition to a feedback controller, the introduction of a feedforward control loop was required to maintain effective control…
On the simulation of stirred tank reactors via computational fluid dynamics
2000
Abstract Predictions of flow fields in a stirred tank reactor, obtained by computational fluid dynamics, were used for the simulation of a mixing sensitive process consisting of two parallel reactions competing for a common reagent: A + B → Prod .1 A + C → Prod .2. Experimental data were obtained for A = OH − , B = 1 2 Cu ++ and C=ethyl-chloroacetate. For this reaction scheme the final selectivity of the process, easily measured by a simple colorimetric analysis of the residual Cu++, was found to depend on agitation speed and therefore on the mixing history during the batch process. The flow field-based three-dimensional simulations performed here led to predictions that compared very well …
A combined CWT-DWT method using model-based design simulator for partial discharges online detection
2009
The suppression of noises is fundamental in onsite Partial Discharge (PD) measurements. For this purpose, the wavelet transform analysis method has been developed and it is a powerful tool for processing the transient and suddenly changing signals. As the wavelet transform possesses the properties of multi-scale analysis and time-frequency domain localization, it is also particularly suitable to process the suddenly changing signals of the partial discharge pulse (PD). In this paper, an improved Wavelet denoising method developed by a model-based design software is presented. Simulations are provided as well as some results obtained during laboratory experiment and on-line PD measurements. …
Lévy Flights for Ant Colony Optimization in Continuous Domains
2009
In this paper, the authors propose the use of the Levy probability distribution as leading mechanism for solutions differentiation in an efficient and bio-inspired optimization algorithm, ant colony optimization in continuous domains, ACOR. In the classical ACOR, new solutions are constructed starting from one solution, selected from an archive, where Gaussian distribution is used for parameter diversification. In the proposed approach, the Levy probability distributions are properly introduced in the solution construction step, in order to couple the ACOR algorithm with the exploration properties of the Levy distribution.
Il precariato nel pubblico impiego: il caso dei modelli viventi
2022
Following a brief excursus of the jurisprudential and scholars’ perspective on the subordinate employment relationship, the note analyses the case of 'living models,' addressing the issue of precariousness in public employment, and the sanctioning consequences from an illegitimate reiteration of fixed-term contracts in the public sector.
Generalized (varphi,psi)-weak contractions involving (f,g)-reciprocally continuous maps in fuzzy metric spaces
2013
We introduce the notion of (f,g)-reciprocal continuity in fuzzy metric spaces and prove a common fixed point theorem for a pair of sub-compatible maps by employing a generalized (varphi,psi)-weak contraction. As an application of our result, we prove a theorem for a (varphi,psi)-weak cyclic contraction in fuzzy metric spaces.
MR2370688 (2009e:46013) Navarro-Pascual, J. C.; Mena-Jurado, J. F.; Sánchez-Lirola, M. G. A two-dimensional inequality and uniformly continuous retra…
2009
Let X be an infinite-dimensional uniformly convex Banach space and let BX and SX be its closed unit ball and unit sphere, respectively. The main result of the paper is that the identity mapping on BX can be expressed as the mean of n uniformly continuous retractions from BX onto SX for every n >= 3. Then, the authors observe that the result holds under a property weaker than uniform convexity, satisfied by any complex Banach space, so that the result generalizes that of [A. Jim´enez-Vargas et al., Studia Math. 135 (1999), no. 1, 75–81; MR1686372 (2000b:46025)]. As an application the extremal structure of spaces of vector-valued uniformly continuous mappings is studied.