Response surface methodology applied for Orange II photocatalytic degradation in TiO2 aqueous suspensions

BACKGROUND: Heterogeneous photocatalysis is influenced by a number of parameters involving synergistic effects; hence, an experimental strategy design that considers interactions between the main variables is needed. The response surface methodology was applied for the investigation of photodegradation of 20 mg L^?1 Orange II in aqueous solutions and for optimization of color removal efficiency. Preliminary studies were performed to identify the parameters to be selected for optimization. RESULTS: The input variables considered for experimental design were: solution initial pH, oxidizing agent (H₂O₂) initial concentration and UV‐A irradiation time. The multivariate experimental design allowed the development of a quadratic response surface model to be used for the prediction of color removal efficiency over the full range of the experimental region. Under the optimum conditions established in the region of experimentation (pH = 6.9, [H₂O₂]₀ = 183 mg L^?1 and t = 32 min), a 100% color removal efficiency was obtained in experiments. CONCLUSIONS: It was found that the variables considered have important effects on color removal efficiency. The results demonstrate that the use of experimental design strategy is indispensable for successful investigation and adequate modeling of the process because the interdependence of the reaction parameters cannot be neglected. Copyright © 2008 Society of Chemical Industry     

A new approach to predict ulcerative colitis activity through standard clinical–biological parameters using a robust neural network model

Neural Computing and Applications - Colonoscopy is the “gold” standard for evaluating disease activity in ulcerative colitis (UC). An important area of research is finding a...     

Validation of static properties in unified modeling language models for cyber physical systems

Cyber physical systems (CPSs) can be found nowadays in various fields of activity. The increased interest for these systems as evidenced by the large number of applications led to complex research regarding the most suitable methods for design and development. A promising solution for specification, visualization, and documentation of CPSs uses the Object Management Group (OMG) unified modeling language (UML). UML models allow an intuitive approach for embedded systems design, helping end-users to specify the requirements. However, the UML models are represented in an informal language. Therefore, it is difficult to verify the correctness and completeness of a system design. The object constraint language (OCL) was defined to add constraints to UML, but it is deficient in strict notations of mathematics and logic that permits rigorous analysis and reasoning about the specifications. In this paper, we investigated how CPS applications modeled using UML deployment diagrams could be formally expressed and verified. We used Z language constructs and prototype verification system (PVS) as formal verification tools. Considering some relevant case studies presented in the literature, we investigated the opportunity of using this approach for validation of static properties in CPS UML models.     

Alcohol effects on intentional behavior: Dissociating controlled and automatic influences.

This research examined the effect of alcohol on intentional behavior using a process dissociation procedure to separate the influences of conscious controlled processes from those of unconscious automatic processes. In 2 identical experiments, 24 male social drinkers studied a list of words before they received either 0.56 g/kg alcohol, an alcohol placebo, or soda. Participants then performed a word stem completion test that provided estimates of controlled influences and of automatic influences on their responses. The results of the 2 experiments were consistent. Comparisons among the treatments showed that alcohol reduced conscious controlled processes and left automatic processes unchanged. The findings contribute to understanding how the drug may reduce cognitive control of intentional behavior and raise important questions concerning personal and environmental factors that might mediate these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

EFFECTS OF GEOMETRY ON HYDRODYNAMICS IN EXTERNAL-LOOP AIRLIFT REACTORS

Experimental investigations were carried out in model external-loop airlift reactors. Two reactors of laboratory scale (riser liquid height ranged between 1.16-1.56 m, riser diameter 0.03 m, A_D/A_R ratio between 0.111-1,000, total liquid volume V_T = (1.189-2.446).10^-3m³) and pilot-plant scale (riser liquid height of 4.4 and 4.7 m, respectively, riser diameter 0.200 m, A_D/A_R ratio of 0.1225 and 0.040 m, total liquid volume, V_T = (0.144-0.170) m³) were used.

The influences of reactor geometry characterized by some parameter as: A_D/A_R ratio, liquid height in riser and downcomer and liquid height in gas separator, together with the amount of introduced air, on the basic hydrodynamic design parameters: gas holdup and liquid circulation velocity were analysed.

The influence of gas sparger design on gas holdup and liquid velocity was found to be negligible.

The experimental liquid circulation velocity was correlated using a simplified form of the energy balance in airlift reactors, valid for external-loop airlift reactors with almost complete phase separation at the top.

An original dimensionless correlation for gas holdup prediction involving superficial velocities of gas and liquid, cross sectional areas, dispersion height, riser diameter, as well as Froude number, was obtained.     

Manifestation of the Wolff-Parkinson-White syndrome during isoprenaline infusion and carotid sinus massage

Fully susceptible cross-bred calves, six to nine months of age, were immunised by tick-induced Theileria annulata infection treated with chlortetracycline at 16 mg/kg body weight for four, eight or 16 days. The infections were induced with 10 ticks (Hyalomma anatolicum anatolicum) or 30 ticks (H dromedarii). The recovered calves were tested for immunity to homologous severe challenge, 50 or 73 days after the first infection. The reaction of the calves to infections was evaluated by noting the prepatent period, symptoms, degree of anaemia, rate of parasitisation of lymphocytes and erythrocytes. It was observed that untreated calves developed acute theileriasis characterised by typical symptoms and lesions and 56 to 66 per cent mortality. The medicated calves, however, developed a mild form of the disease. Calves which recovered from treated or untreated infections were solidly resistant to subsequent severe homologous infection. Judged from the severity of anaemia in the infected calves, eight day and 16 day medication provided slightly better protection than four day medication. It was concluded that eight day medication afforded adequate protection against the severe immunising infection, and allowed the development of solid resistance to severe homologous challenge.     

Engineering concerns and new developments in anaerobic waste-water treatment

A non-comprehensive review of several developments in the field of anaerobic biological waste-water treatment engineering is carried out, considering the active role engineers have to play in this field. The analysis is done as a result of the fact that the general performance of anaerobic systems and the diversity of wastes that these can treat are increasing as a result of new reactor design, operating conditions, and use of specialized microorganisms. This paper illustrates a few examples of conventional and new applications of anaerobic treatment and several advantages, such as no energy-intensive oxygen transfer, less excess sludge, production of combustible biogas, and space saving. Such an overview of biological waste-water treatment also precedes comments on some important aspects on process microbiology as well as considerations of the application of fundamentals and kinetics to the analysis of the biological processes used most commonly for anaerobic biological waste-water treatment. Models developed for this reaction type are discussed, considering four overall steps. Also, models for a continuous-stirred tank bioreactor, a fluidized bed reactor, and a packed bed reactor as basic configurations are described. Major anaerobic biological treatment processes used for waste-water treatment, both suspended-growth processes and reactors (anaerobic stirred tank, anaerobic contact process, upflow anaerobic sludge-blanket process) and attached-growth processes and reactors (anaerobic filter process, expanded-bed process), are considered. It was also shown that the breakthroughs dealing with reactor design and operating conditions offer practical solutions to many of the drawbacks that were initially thought to limit the purpose of anaerobic processes. Finally, the paper includes some aspects regarding the control of anaerobic biological systems. Electronic Publication