In order to provide more sensitive monitoring results, the time dynamics and steady-state operating conditions should be separately monitored by distinguishing time information from the steady-state ...counterpart. However, it is a more challenging task for batch processes because they vary from phase to phase presenting multiple steady states and complex dynamic characteristics. To address the above issue, a concurrent monitoring strategy of multiphase steady states and process dynamics is developed for batch processes in this paper. On one hand, multiple local models are constructed to identify a steady derivation from the normal operating condition for different phases. On the other hand, based on the recognition that the process dynamics can be considered to be irrelevant with the steady states, a global model is built to detect the dynamics anomalies by monitoring the time variations. Corresponding to alarms issued by different statistics, different operating statuses are indicated with meaningful physical interpretation and deep process understanding. To illustrate the feasibility and efficacy, the proposed algorithm is applied to the injection molding process, which is a typical multiphase batch process.
The geometry which is the topic of this book is that determined by a map of one space N onto another, M, mapping a diffusion process, or operator, on N to one on M. Filtering theory is the science of ...obtaining or estimating information about a system from partial and possibly flawed observations of it. The system itself may be random, and the flaws in the observations can be caused by additional noise. In this volume the randomness and noises will be of Gaussian white noise type so that the system can be modelled by a diffusion process, that is it evolves continuously in time in a Markovian way, the future evolution depending only on the present situation. This is the standard situation of systems governed by Ito type stochastic differential equations. The state space will be the smooth manifold, N, possibly infinite dimensional, and the 'observations' will be obtained by a smooth map onto another manifold, N, say. We emphasise that the geometry is important even when both manifolds are Euclidean spaces. This can also be viewed from a purely partial differential equations viewpoint as one smooth second order elliptic partial differential operator lying above another, both with no zero order term. We consider the geometry of this situation with special emphasis on situations of geometric, stochastic analytic, or filtering interest. The most well studied case is of one Brownian motion being mapped to another with a consequent skew product decomposition (or equivalently the case of Riemannian submersions). This sort of decomposition is generalised and a key to the rest of the book. It is used to study in particular, classical filtering, (semi-)connections determined by stochastic flows, and generalised Weitzenbock formulae.
This perspective illustrates the electromagnetic induction heating technology for a rational heat control in catalytic heterogeneous processes. It mainly focuses on the remarkable advantages of this ...approach in terms of process intensification, energy efficiency, reactor setup simplification, and safety issues coming from the use of radio frequency heated susceptors/catalysts in fixed-bed reactors under flow operational conditions. It is a real enabling technology that allows a catalytic process to go beyond reactor bounds, reducing inefficient energy transfer issues and heat dissipation phenomena while improving reactor hydrodynamics. Hence, it allows pushing catalytic processes to the limits of their kinetics. Undoubtedly, inductive heating represents a twist in performing catalysis. Indeed, it offers unique solutions to overcome heat transfer limitations (i.e. slow heating/cooling rates, nonuniform heating environments, low energy efficiency) to those endo- and exothermic catalytic transformations that make use of conventional heating methodologies.
For Markov processes with absorption, we provide general criteria ensuring the existence and the exponential non-uniform convergence in total variation norm to a quasi-stationary distribution. We ...also characterize a subset of its domain of attraction by an integrability condition, prove the existence of a right eigenvector for the semigroup of the process and the existence and exponential ergodicity of the Q-process. These results are applied to one-dimensional and multi-dimensional diffusion processes, to pure jump continuous time processes, to reducible processes with several communication classes, to perturbed dynamical systems and discrete time processes evolving in discrete state spaces.
With the growing concern about global warming placing greater demands on improving energy efficiency and reducing CO
2
emissions, the need for improving the energy intensive, separation processes ...involving CO
2
is well recognized. The US Department of Energy estimates that the separation of CO
2
represents 75% of the cost associated with its separation, storage, transport, and sequestration operations. Hence, energy efficient, CO
2
separation technologies with improved economics are needed for industrial processing and for future options to capture and concentrate CO
2
for reuse or sequestration. The overall goal of this review is to foster the development of new adsorption and membrane technologies to improve manufacturing efficiency and reduce CO
2
emissions. This study focuses on the power, petrochemical, and other CO
2
emitting industries, and provides a detailed review of the current commercial CO
2
separation technologies, i.e., absorption, adsorption, membrane, and cryogenic, an overview of the emerging adsorption and membrane technologies for CO
2
separation, and both near and long term recommendations for future research on adsorption and membrane technologies. Flow sheets of the principal CO
2
producing processes are provided for guidance and new conceptual flow sheets with ideas on the placement of CO
2
separations technologies have also been devised.
•Three categories of FBR-Fenton processes for industrial wastewater treatment.•Factors to enhance organics removal and iron crystallization efficiency are reviewed.•Technology upscaling of ...FBR-Fenton-like processes is challenging.•Strategies to tackle technical limitations and enhance process cost-effectiveness.
In recent years, fluidized-bed Fenton (FBR-Fenton) process has gained more attention in treating recalcitrant industrial wastewater. FBR-Fenton combines the effectiveness of homogeneous Fenton and sludge reduction of heterogeneous Fenton. Comparing to other modified Fenton processes, FBR-Fenton has greater economical and scaling up potential. However, large consumption of Fenton reagents and strict pH control are still the bottlenecks hampering the full-scale application of FBR-Fenton. While prior reviews mainly focused on the operation and performance of FBR-Fenton process, the present study critically discussed the challenges and bottlenecks for its full-scale industrial application. This study also comprehensively reviewed the development strategies for tackling these drawbacks, mainly over the recent five years. Homogeneous FBR-Fenton, heterogeneous FBR-Fenton and heterogeneous FBR-photo-Fenton processes were classified for the first time according to their reaction mechanisms and system designs. Important operational and design parameters affecting the cost-effectiveness of all FBR-Fenton technologies were reviewed, including the fundamentals, common practices and even innovative steps for enhancing the process performance. Up-to-date applications of FBR-Fenton technologies in recalcitrant wastewater/compounds treatment were also summarized, and it was found that upscaling of heterogeneous FBR-Fenton and heterogeneous FBR-photo-Fenton processes was still very challenging. Strategies to overcome the key technical limitations and enhance process cost-effectiveness were discussed in the future perspective part. Furthermore, modelling techniques such as computational fluid dynamics model and artificial neural network were suggested to be promising modelling techniques for speeding up the full-scale applications of FBR-Fenton technologies.
Display omitted
One of the major environmental problems caused by the agro-food industry is the treatment of olive mill wastewater (OMW). OMW is a byproduct of olive oil production and is characterized by high ...concentrations of various organic compounds, including organic acids, pectin, and polyphenols, as well as inorganic compounds like sulfate, chlorides, and phosphoric salts of potassium and sodium, and trace amounts of other elements. These compounds make OMW complex and toxic to plants, inhibiting bacterial activity. Therefore, these compounds must be removed from wastewater before it is discharged into the environment. Many conventional treatment processes for OMW have been used, relying on physical, biological, and chemical methods. However, they have limitations and low efficiency in removing pollutants, as they only transfer pollutants from one stage to another. The ultimate goal of any treatment process is to achieve complete mineralization of pollutants, which can be achieved through the integration of appropriate processes. Over the years, many researchers have evaluated various combined treatment methods to enhance treatment efficiency and comply with environmental regulations regarding wastewater discharge. This review focuses on combined treatment methods for treated OMW. We analyzed preliminary results in the literature and discussed many parameters used to improve the process. Additionally, this review summarizes the combined processes according to their respective types, along with their benefits, drawbacks, and future prospects. It also summarizes the environmental impacts of treating OMW. In general, the results extracted from the literature review show that combined treatment processes have proven effective in treating OMW and should remain a focal point for the development of enhanced processes that can remove more pollutants in a single process.
Display omitted
•The review summarizes the performance of more than 54 combined processes in removing various pollutants from olive mill wastewater (OMW).•Combined processes are more convincing and efficient than single processes for OMW treatment.•The study found that combined chemical-chemical and chemical-biological treatment processes are OMW's most common and widely used combination treatments.•Fenton and coagulation/flocculation (C/F) methods are the best treatments to be integrated as combined methods.
Statistical Analysis of a Telephone Call Center Brown, Lawrence; Gans, Noah; Mandelbaum, Avishai ...
Journal of the American Statistical Association,
03/2005, Letnik:
100, Številka:
469
Journal Article
Recenzirano
Odprti dostop
A call center is a service network in which agents provide telephone-based services. Customers who seek these services are delayed in tele-queues. This article summarizes an analysis of a unique ...record of call center operations. The data comprise a complete operational history of a small banking call center, call by call, over a full year. Taking the perspective of queueing theory, we decompose the service process into three fundamental components: arrivals, customer patience, and service durations. Each component involves different basic mathematical structures and requires a different style of statistical analysis. Some of the key empirical results are sketched, along with descriptions of the varied techniques required. Several statistical techniques are developed for analysis of the basic components. One of these techniques is a test that a point process is a Poisson process. Another involves estimation of the mean function in a nonparametric regression with lognormal errors. A new graphical technique is introduced for nonparametric hazard rate estimation with censored data. Models are developed and implemented for forecasting of Poisson arrival rates. Finally, the article surveys how the characteristics deduced from the statistical analyses form the building blocks for theoretically interesting and practically useful mathematical models for call center operations.
Landfill leachate is a type of complex organic wastewater, which can easily cause serious negative impacts on the human health and ecological environment if disposed improperly. Electrochemical ...technology provides an efficient approach to effectively reduce the pollutants in landfill leachate. In this review, the electrochemical standalone processes (electrochemical oxidation, electrochemical reduction, electro-coagulation, electro-Fenton process, three-dimensional electrode process, and ion exchange membrane electrochemical process) and the electrochemical integrated processes (electrochemical-advanced oxidation process (AOP) and biological electrochemical process) for landfill leachate treatment are summarized, which include the performance, mechanism, application, existing problems, and improvement schemes such as cost-effectiveness. The main objective of this review is to help researchers understand the characteristics of electrochemical treatment of landfill leachate and to provide a useful reference for the design of the process and reactor for the harmless treatment of landfill leachate.
Display omitted
•Electrochemical processes for landfill leachate treatment•Advantages and shortcomings of electrochemical processes•Improvement schemes of electrochemical processes•Future research needs on landfill leachate electrochemical treatment
PDF
