Desarrollo y aplicación de estrategias de control avanzado en procesos biológicos de tratamiento de efluentes contaminados

En este proyecto se ha desarrollado estrategias de control avanzadas para plantas de depuración de aguas residuales urbanas que eliminan conjuntamente materia orgánica, nitrógeno y fósforo. Las estrategias se han basado en el estudio multivariable del comportamiento del sistema, que ha producido subsidios para la utilización de lazos de control feedforward, de control predictivo y de un control de costes que automáticamente enviaba las consignas más adecuadas para los controladores de proceso. Para el desarrollo de las estrategias, se ha creado un sistema virtual de simulación (simulador) de plantas de depuradoras, basado en datos de literatura. Para el caso de una planta real, se ha desarrollado un simulador de la planta de Manresa (Catalunya). Sin embargo, el sistema de Manresa se ha utilizado exclusivamente para auxiliar los ingenieros de la planta en la tomada de decisiones de cambio de configuración para que la eliminación de fósforo se dé por la ruta biológica y no por la ruta química. La implementación de los simuladores ha permitido hacer muchas pruebas que en una planta real demandarían mucho tiempo y consumirían muchos recursos energéticos y financieros. Las estrategias de control más elaboradas han podido ahorrar hasta 150.000,00 Euros por año en relación a la operación de la planta sin el control automático. Cuanto a los estudios del modelo de la planta real, se concluyó que la eliminación biológica de fósforo puede sustituir el actual proceso químico de eliminación de fósforo, bajando los costes operacionales (costes del agente precipitante).

Transfer of toxin genes to alternate bacterial hosts for mosquito control

Mosquitoes are vector of serious human and animal diseases, such as malaria, dengue, yellow fever, among others. The use of biological control agents has provide an environmentally safe and highly specific alternative to the use of chemical insecticides in the control of vector borne diseases. Bacillus thuringiensis and B. sphaericus produce toxic proteins to mosquito larvae. Great progress has been made on the biochemical and molecular characterization of such proteins and the genes encoding them. Nevertheless, the low residuality of these biological insecticides is one of the major drawbacks. This article present some interesting aspects of the mosquito larvae feeding habits and review the attempts that have been made to genetically engineer microorganisms that while are used by mosquito larvae as a food source should express the Bacillus toxin genes in order to improve the residuality and stability in the mosquito breeding ponds.

Current concepts of snail control

Schistosomiasis control was impossible without effective tools. Synthetic molluscicides developed in the 1950s spearheaded community level control. Snail eradication proved impossible but repeated mollusciciding to manage natural snail populations could eliminate transmission. Escalating costs, logistical complexity, its labour-intensive nature and possible environmental effects caused some concern. The arrival of safe, effective, single-dose drugs in the 1970s offered an apparently better alternative but experience revealed the need for repeated treatments to minimise reinfection in programmes relying on drugs alone. Combining treatment with mollusciciding was more successful, but broke down if mollusciciding was withdrawn to save money. The provision of sanitation and safe water to prevent transmission is too expensive in poor rural areas where schistosomiasis is endemic; rendering ineffective public health education linked to primary health care. In the tropics, moreover, children (the key group in maintaining transmission) will always play in water. Large scale destruction of natural snail habitats remains impossibly expensive (although proper design could render many new man-made habitats unsuitable for snails). Neither biological control agents nor plant molluscicides have proved satisfactory alternatives to synthetic molluscicides. Biologists can develop effective strategies for using synthetic molluscicides in different epidemiological situations if only, like drugs, their price can be reduced.

Abstracting qualitative information for process supervision

Supervisory systems evolution makes the obtaining of significant information from processes more important in the way that the supervision systems' particular tasks are simplified. So, having signal treatment tools capable of obtaining elaborate information from the process data is important. In this paper, a tool that obtains qualitative data about the trends and oscillation of signals is presented. An application of this tool is presented as well. In this case, the tool, implemented in a computer-aided control systems design (CACSD) environment, is used in order to give to an expert system for fault detection in a laboratory plant

I-SS: integrated supervision systems approach based on interactive components

Process supervision is the activity focused on monitoring the process operation in order to deduce conditions to maintain the normality including when faults are present Depending on the number/distribution/heterogeneity of variables, behaviour situations, sub-processes, etc. from processes, human operators and engineers do not easily manipulate the information. This leads to the necessity of automation of supervision activities. Nevertheless, the difficulty to deal with the information complicates the design and development of software applications. We present an approach called "integrated supervision systems". It proposes multiple supervisors coordination to supervise multiple sub-processes whose interactions permit one to supervise the global process

Comparative biology of Cycloneda sanguinea (Linnaeus, 1763) and Hippodamia convergens Guérin-Méneville, 1842 (Coleoptera, Coccinellidae) focusing on the control of Cinara spp. (Hemiptera, Aphididae)

The giant conifer aphids Cinara pinivora (Wilson, 1919) and Cinara atlantica (Wilson, 1919) (Hemiptera, Aphididae) have been observed attacking Pinus spp. in Southern and Southeastern Brazil. The coccinellids, on the other hand, were found feeding on these aphids in the field, which can be regarded as potential biological control agents. The biological cycle and mortality rate of larvae of Cycloneda sanguinea (Linnaeus, 1763) and Hippodamia convergens Guérin-Méneville, 1842 (Coleoptera, Coccinellidae) were evaluated using twenty larvae of each predator species fed with nymphs of Cinara. The vials with the insects were kept under 15 ºC, 20 ºC and 25 ºC, with 12h photophase and 70 ± 10% relative humidity. The consumption was evaluated every 24 hours and the nymphs replaced. For C. sanguinea, the egg incubation time was 10.5, 5.0 and 4.0 days; the average larval development period was 33.3, 15.8 and 8.6 days and the larval mortality rate 20%,0% and 15%, respectively at 15 ºC, 20 ºC and 25 ºC. For H. convergens, the larval development time was 41.9, 19.3 and 10.9 days at 15 ºC, 20 ºC and 25 ºC, respectively. The larval mortality rate was 35%, 15% and 0% under the three temperatures. Both species developed adequately when fed nymphs of Cinara, however, C. sanguinea performed better than H. convergens, even at 15 ºC, at which temperature the biological cycles of the coccinellids are prolonged, but the temperature is favorable for the development of Cinara populations in the field.

Aplicació en línia d'un sistema variable de control multivariable en un Reactor ..

L’objecte del present treball és la realització d’una aplicació que permeti portar a terme el control estadístic multivariable en línia d’una planta SBR.Aquesta eina ha de permetre realitzar un anàlisi estadístic multivariable complet del lot en procés, de l’últim lot finalitzat i de la resta de lots processats a la planta.L’aplicació s’ha de realitzar en l’entorn LabVIEW. L’elecció d’aquest programa vecondicionada per l’actualització del mòdul de monitorització de la planta que s’estàdesenvolupant en aquest mateix entorn

Embankment Quality and Assessment of Moisture Control Implementation, TR-677, 2016

A specification for contractor moisture quality control (QC) in roadway embankment construction has been in use for approximately 10 years in Iowa on about 190 projects. The use of this QC specification and the development of the soils certification program for the Iowa Department of Transportation (DOT) originated from Iowa Highway Research Board (IHRB) embankment quality research projects. Since this research, the Iowa DOT has applied compaction with moisture control on most embankment work under pavements. This study set out to independently evaluate the actual quality of compaction using the current specifications. Results show that Proctor tests conducted by Iowa State University (ISU) using representative material obtained from each test section where field testing was conducted had optimum moisture contents and maximum dry densities that are different from what was selected by the Iowa DOT for QC/quality assurance (QA) testing. Comparisons between the measured and selected values showed a standard error of 2.9 lb/ft3 for maximum dry density and 2.1% for optimum moisture content. The difference in optimum moisture content was as high as 4% and the difference in maximum dry density was as high as 6.5 lb/ft3 . The difference at most test locations, however, were within the allowable variation suggested in AASHTO T 99 for test results between different laboratories. The ISU testing results showed higher rates of data outside of the target limits specified based on the available contractor QC data for cohesive materials. Also, during construction observations, wet fill materials were often observed. Several test points indicated that materials were placed and accepted at wet of the target moisture contents. The statistical analysis results indicate that the results obtained from this study showed improvements over results from previous embankment quality research projects (TR-401 Phases I through III and TR-492) in terms of the percentage of data that fell within the specification limits. Although there was evidence of improvement, QC/QA results are not consistently meeting the target limits/values. Recommendations are provided in this report for Iowa DOT consideration with three proposed options for improvements to the current specifications. Option 1 provides enhancements to current specifications in terms of material-dependent control limits, training, sampling, and process control. Option 2 addresses development of alternative specifications that incorporate dynamic cone penetrometer or light weight deflectometer testing into QC/QA. Option 3 addresses incorporating calibrated intelligent compaction measurements into QC/QA.

Control and Simulation of Batch Crystallization

Concerning process control of batch cooling crystallization the present work focused on the cooling profile and seeding technique. Secondly, the influence of additives on batch-wise precipitation process was investigated. Moreover, a Computational Fluid Dynamics (CFD) model for simulation of controlled batch cooling crystallization was developed. A novel cooling model to control supersaturation level during batch-wise cooling crystallization was introduced. The crystallization kinetics together with operating conditions, i.e. seed loading, cooling rate and batch time, were taken into account in the model. Especially, the supersaturation- and suspension density- dependent secondary nucleation was included in the model. The interaction between the operating conditions and their influence on the control target, i.e. the constant level of supersaturation, were studied with the aid of a numerical solution for the cooling model. Further, the batch cooling crystallization was simulated with the ideal mixing model and CFD model. The moment transformation of the population balance, together with the mass and heat balances, were solved numerically in the simulation. In order to clarify a relationship betweenthe operating conditions and product sizes, a system chart was developed for anideal mixing condition. The utilization of the system chart to determine the appropriate operating condition to meet a required product size was introduced. With CFD simulation, batch crystallization, operated following a specified coolingmode, was studied in the crystallizers having different geometries and scales. The introduced cooling model and simulation results were verified experimentallyfor potassium dihydrogen phosphate (KDP) and the novelties of the proposed control policies were demonstrated using potassium sulfate by comparing with the published results in the literature. The study on the batch-wise precipitation showed that immiscible additives could promote the agglomeration of a derivative of benzoic acid, which facilitated the filterability of the crystal product.

Automated monitoring of medical protocols: a secure and distributed architecture

The control of the right application of medical protocols is a key issue in hospital environments. For the automated monitoring of medical protocols, we need a domain-independent language for their representation and a fully, or semi, autonomous system that understands the protocols and supervises their application. In this paper we describe a specification language and a multi-agent system architecture for monitoring medical protocols. We model medical services in hospital environments as specialized domain agents and interpret a medical protocol as a negotiation process between agents. A medical service can be involved in multiple medical protocols, and so specialized domain agents are independent of negotiation processes and autonomous system agents perform monitoring tasks. We present the detailed architecture of the system agents and of an important domain agent, the database broker agent, that is responsible of obtaining relevant information about the clinical history of patients. We also describe how we tackle the problems of privacy, integrity and authentication during the process of exchanging information between agents.

Control of Guignardia citricarpa by Bacillus subtilis and Trichoderma spp.

The ability of isolates of Bacillus subtilis and Trichoderma spp. to control citrus black spot (CBS) was investigated in ´Natal´ sweet orange orchards. The first experiment was conducted during the 2001/2002 season and four isolates of B. subtilis (ACB-AP3, ACB-69, ACB-72 and ACB-77), applied every 28 days, alone or in combination were tested and compared with fungicide treatments. Two other experiments were carried out during the 2002/2003 season, where the same isolates of Bacillus and two isolates of Trichoderma (ACB-14 and ACB-40) were tested being applied every 28 days in the second experiment, and every 15 days in the third experiment. In the first experiment, the treatment with ACB-69 differed statistically from the control, but did not differ from other biological control agents or mixture of Bacillus isolates. In the second experiment, the treatments with ACB-69 and ACB-AP3 resulted in smaller disease index compared with the control treatment. However, this result was not repeated in the third experiment, where the isolates were applied every 15 days. Disease severity was high in both evaluated seasons and the fungicide treatment was the most effective for disease control.

Balancing effluent quality, economic cost and greenhouse gas emissions during the evaluation of (plant-wide) control/operational strategies in WWTPs

The objective of this paper was to show the potential additional insight that result from adding greenhouse gas (GHG) emissions to plant performance evaluation criteria, such as effluent quality (EQI) and operational cost (OCI) indices, when evaluating (plant-wide) control/operational strategies in wastewater treatment plants (WWTPs). The proposed GHG evaluation is based on a set of comprehensive dynamic models that estimate the most significant potential on-site and off-site sources of CO2, CH4 and N2O. The study calculates and discusses the changes in EQI, OCI and the emission of GHGs as a consequence of varying the following four process variables: (i) the set point of aeration control in the activated sludge section; (ii) the removal efficiency of total suspended solids (TSS) in the primary clarifier; (iii) the temperature in the anaerobic digester; and (iv) the control of the flow of anaerobic digester supernatants coming from sludge treatment. Based upon the assumptions built into the model structures, simulation results highlight the potential undesirable effects of increased GHG production when carrying out local energy optimization of the aeration system in the activated sludge section and energy recovery from the AD. Although off-site CO2 emissions may decrease, the effect is counterbalanced by increased N2O emissions, especially since N2O has a 300-fold stronger greenhouse effect than CO2. The reported results emphasize the importance and usefulness of using multiple evaluation criteria to compare and evaluate (plant-wide) control strategies in a WWTP for more informed operational decision making

Effect of hydrodynamics on modelling, monitoring and control of crystallization

Crystallization is a purification method used to obtain crystalline product of a certain crystal size. It is one of the oldest industrial unit processes and commonly used in modern industry due to its good purification capability from rather impure solutions with reasonably low energy consumption. However, the process is extremely challenging to model and control because it involves inhomogeneous mixing and many simultaneous phenomena such as nucleation, crystal growth and agglomeration. All these phenomena are dependent on supersaturation, i.e. the difference between actual liquid phase concentration and solubility. Homogeneous mass and heat transfer in the crystallizer would greatly simplify modelling and control of crystallization processes, such conditions are, however, not the reality, especially in industrial scale processes. Consequently, the hydrodynamics of crystallizers, i.e. the combination of mixing, feed and product removal flows, and recycling of the suspension, needs to be thoroughly investigated. Understanding of hydrodynamics is important in crystallization, especially inlargerscale equipment where uniform flow conditions are difficult to attain. It is also important to understand different size scales of mixing; micro-, meso- and macromixing. Fast processes, like nucleation and chemical reactions, are typically highly dependent on micro- and mesomixing but macromixing, which equalizes the concentrations of all the species within the entire crystallizer, cannot be disregarded. This study investigates the influence of hydrodynamics on crystallization processes. Modelling of crystallizers with the mixed suspension mixed product removal (MSMPR) theory (ideal mixing), computational fluid dynamics (CFD), and a compartmental multiblock model is compared. The importance of proper verification of CFD and multiblock models is demonstrated. In addition, the influence of different hydrodynamic conditions on reactive crystallization process control is studied. Finally, the effect of extreme local supersaturation is studied using power ultrasound to initiate nucleation. The present work shows that mixing and chemical feeding conditions clearly affect induction time and cluster formation, nucleation, growth kinetics, and agglomeration. Consequently, the properties of crystalline end products, e.g. crystal size and crystal habit, can be influenced by management of mixing and feeding conditions. Impurities may have varying impacts on crystallization processes. As an example, manganese ions were shown to replace magnesium ions in the crystal lattice of magnesium sulphate heptahydrate, increasing the crystal growth rate significantly, whereas sodium ions showed no interaction at all. Modelling of continuous crystallization based on MSMPR theory showed that the model is feasible in a small laboratoryscale crystallizer, whereas in larger pilot- and industrial-scale crystallizers hydrodynamic effects should be taken into account. For that reason, CFD and multiblock modelling are shown to be effective tools for modelling crystallization with inhomogeneous mixing. The present work shows also that selection of the measurement point, or points in the case of multiprobe systems, is crucial when process analytical technology (PAT) is used to control larger scale crystallization. The thesis concludes by describing how control of local supersaturation by highly localized ultrasound was successfully applied to induce nucleation and to control polymorphism in reactive crystallization of L-glutamic acid.

Delay reduction in courts of justice – possibilities and challenges of process improvement in professional public organizations

Delays in the justice system have been undermining the functioning and performance of the court system all over the world for decades. Despite the widespread concern about delays, the solutions have not kept up with the growth of the problem. The delay problem existing in the justice courts processes is a good example of the growing need and pressure in professional public organizations to start improving their business process performance.This study analyses the possibilities and challenges of process improvement in professional public organizations. The study is based on experiences gained in two longitudinal action research improvement projects conducted in two separate Finnish law instances; in the Helsinki Court of Appeal and in the Insurance Court. The thesis has two objectives. First objective is to study what kinds of factors in court system operations cause delays and unmanageable backlogs and how to reduce and prevent delays. Based on the lessons learned from the case projects the objective is to give new insights on the critical factors of process improvement conducted in professional public organizations. Four main areas and factors behind the delay problem is identified: 1) goal setting and performance measurement practices, 2) the process control system, 3) production and capacity planning procedures, and 4) process roles and responsibilities. The appropriate improvement solutions include tools to enhance project planning and scheduling and monitoring the agreed time-frames for different phases of the handling process and pending inventory. The study introduces the identified critical factors in different phases of process improvement work carried out in professional public organizations, the ways the critical factors can be incorporated to the different stages of the projects, and discusses the role of external facilitator in assisting process improvement work and in enhancing ownership towards the solutions and improvement. The study highlights the need to concentrate on the critical factors aiming to get the employees to challenge their existing ways of conducting work, analyze their own processes, and create procedures for diffusing the process improvement culture instead of merely concentrating of finding tools, techniques, and solutions appropriate for applications from the manufacturing sector

System for studies of control strategies applied in the refrigerated chambers

The process of cold storage chambers contributes largely to the quality and longevity of stored products. In recent years, it has been intensified the study of control strategies in order to decrease the temperature change inside the storage chamber and to reduce the electric power consumption. This study has developed a system for data acquisition and process control, in LabVIEW language, to be applied in the cooling system of a refrigerating chamber of 30m³. The use of instrumentation and the application developed fostered the development of scientific experiments, which aimed to study the dynamic behavior of the refrigeration system, compare the performance of control strategies and the heat engine, even due to the controlled temperature, or to the electricity consumption. This system tested the strategies for on-off control, PID and fuzzy. Regarding power consumption, the fuzzy controller showed the best result, saving 10% when compared with other tested strategies.