A gas-lift oil well is an oil well that uses high-pressure natural gas to improve oil production. This type of oil well is unstable if not enough gas is available for operation, when a phenomenon ...called slugging may occur. Besides slugging, other relevant challenges of the problem are unknown internal state and well parameters and unmeasurable disturbances. In this work, a nonlinear model predictive controller (NMPC) for this type of oil well was developed. To build this NMPC, a parameter estimation was performed with data gathered by a four-factor design of experiments. Using the internal states generated during the parameter estimation, a machine learning algorithm was trained to infer the internal state from sensor data. The NMPC was tested against slugging, set point changes, and unmeasurable disturbances and compared with results from both a perfect NMPC and an NMPC with states estimated by extended Kalman filter. Estimation of the internal states by the neural network was accurate enough to allow for proper control. The NMPC actions were aggressive but successfully curbed slugging and kept the controlled variables around their set points. The main contributions of this work are developing a methodology for state inference supported by neural networks and presenting a pair of nonlinear models for model mismatch studies.
To investigate the relationship between ultra-processed food consumption and early childhood caries.
Cross-sectional analysis of baseline data from a cluster randomised controlled study. Outcomes ...included the prevalence of children with non-cavitated and cavitated caries. The main exposure was the total daily consumption of ultra-processed foods (up to three times and four times or more), assessed through a FFQ. Potential confounders were socio-demographic characteristics of the child and caregiver/family, child breast-feeding, oral hygiene and use of dental services. Poisson regression using robust variance adjustment was used to estimate prevalence ratios (PR) and their respective 95 % CI.
Primary Healthcare Centers in an urban area of Pelotas, Southern Brazil.
Children aged 0-3 years (n 309).
Consumption of ultra-processed foods four times or more a day was found in 67·6 % of children; 24·4 and 12·0 % presented non-cavitated and cavitated caries, respectively. After adjustment, children who consumed ultra-processed foods four times or more a day were more likely to present both non-cavitated caries (PR 2·25, 95 % CI 1·19, 4·27, P = 0·013) and cavitated caries (PR 3·48, 95 % CI 1·18, 10·30, P = 0·024) compared with those who have consumed them up to three times a day.
Consumption of ultra-processed foods is associated with early childhood caries. Interventions aiming at reducing ultra-processed food consumption should be implemented to improve children's oral health.
•Thermodynamics and Supramolecular chemistry aid the design of chitosan particles.•Bulk and Interfacial complexation of chitosan demand different design strategies.•Initial polyelectrolyte solution ...properties can interfere in particle formation.•EDL properties of polyelectrolyte solution is an important design parameter.•Bridging theory and experiments fosters an improved control of particle properties.
Chitosan-based particles are widely proposed as biocompatible drug delivery systems with mucoadhesive and permeation enhancing properties. However, strategies on how to modulate the intended biological responses are still scarce. Considering that particle properties affect the biological outcome, the rational design of the synthesis variables should be proposed to engineer drug delivery systems with improved biological performance. The purpose of this review is to establish a deeper understanding of possible correlations between these variables and the particle properties from theoretical and experimental perspectives. The fundamental physicochemical knowledge of chitosan-based polyelectrolyte complexation and surface modification is discussed focusing on chitosan-TPP, polyelectrolyte complexes, and chitosan-surface modified PLGA or lipid particles. A set of design considerations is proposed to enable future investigation in the development of chitosan particles with modulated properties. The approach presented here contributes to the rational design of chitosan-based particles that meet different requirements for biological activities.
(
) is a Brazilian medicinal plant known for its pharmacological properties, including healing activity related to its phenolic composition, which is chiefly given by tannins. In order to preserve ...its stability and bioactivity,
extracts can be incorporated into (bio-)polymeric matrixes, of which silk fibroin stands out due to its versatility and tunable properties. This work aimed to obtain
bark extract rich in phenolic compounds and evaluate its incorporation in fibroin hydrogels. From the extraction process, it was observed that the PG (propylene glycol) extract presented a higher global yield (X
) and phenolic compounds (TPC) than the ET (ethanol) extract. Furthermore, the antioxidant activity (ORAC and FRAP) was similar between both extracts. Regarding the hydrogels, morphological, chemical, thermal, and mechanical characterizations were performed to understand the influence of the
extract and the solvent on the fibroin hydrogel properties. As a result, the hydrogels containing the
PG extract (BT/PG hydrogels) showed the better physical-chemical and structural performance. Therefore, these hydrogels should be further investigated regarding their potential in medical and pharmaceutical applications, especially in wound healing.
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•Mucoadhesive systems for vaginal administration.•Mucoadhesive systems composed of chitosan.•Mucoadhesive systems composed of chitosan intended for the treatment of infectious vaginal ...diseases.
Vaginal administration is a promising route for the local treatment of infectious vaginal diseases since it can bypass the first-pass metabolism, drug interactions, and adverse effects. However, the commercial products currently available for topical vulvovaginal treatment have low acceptability and do not adequately explore this route. Mucoadhesive systems can optimize the efficacy of drugs administered by this route to increase the retention time of the drug in the vaginal environment. Several polymers are used to develop mucoadhesive systems, among them chitosan, a natural polymer that is highly biocompatible and technologically versatile. Thus, the present review aimed to analyze the studies that used chitosan to develop mucoadhesive systems for the treatment of local vaginal infections. These studies demonstrated that chitosan as a component of mucoadhesive drug delivery systems (DDS) is a promising device for the treatment of vaginal infectious diseases, due to the intrinsic antimicrobial activity of this biopolymer and because it does not interfere with the effectiveness of the drugs used for the treatment.
This article deals with a parallel machine scheduling problem subject to non-interference constraints. This situation often appears at logistic centres, such as depots, warehouses and stockyards. The ...analyzed scenario is based on a real case at a distribution centre of steel coils, where two cranes using the same rail must load dispatching trucks. We analyze this case by modelling the situation through a parallel machine perspective and considering two mechanisms to deal with the machine interference,
. In the first approach, the machine interference is dealt by scheduling whole trucks. In the second one, we schedule the trucks and the coils within. The proposed mathematical models are able to solve small and medium instances, thus, we develop two genetic algorithms to solve real size instances, allowing the analysis of different storage policies. Results show that the genetic approach is able to find near-optimal solutions independently of the policy, with solutions gap ranging from 10 to 2.1%.
This paper presents the characteristics of the high resolution secondary ion mass spectrometer coupled with an Ion Micro - probe (SHRIMP IIe/MC), installed at the Institute of Geosciences of the ...University of São Paulo (IGc-USP), as well as the respective analytical procedures and the first results obtained with standard samples, making possible to conduct routine analysis of zircon samples. The standard of the Temora 2 zircon, with age of 416.78 Ma, was analyzed by the SHRIMP IIe/ MC at the Institute of Geosciences of the University of São Paulo and yielded the age of 416.8 ± 3.8 Ma. Samples of the Ar - chean zircon OG1 and the Neoproterozoic zircon Z6266, which yielded U-Pb ages of 3465.4 ± 0.6 Ma and of 559 ± 0.2 Ma, respectively, using Thermal Ionization Mass Spectrometry (TIMS), were analyzed by SHRIMP IIe/MC at the IG-USP and yielded U-Pb ages of 3462.6 ± 5.1 Ma and 561.0 ± 0.92 Ma, respectively, in Concordia diagrams. Therefore, these values and the literature values are very close. Both OG1 and Z6266 samples, due to the homogeneity in their composition and isotopic relationship, can be used as SHRIMP standard. These results indicate that data obtained using SHRIMP IIe at the IGc-USP are reliable and compatible with international standards. Dating of samples with ages ranging from Cenozoic to Archean, obtained using SHRIMP IIe/MC U-Pb geochronology on zircon crystals, is presented here to illustrate this point.
An attractive method for steady-state real-time optimization (RTO) using transient measurements consists of a persistent parameter adaptation throughout a dynamic parameter estimation followed by a ...static economic optimization. The method is called RTO with persistent parameter adaptation (ROPA) or Hybrid RTO (HRTO). Although such a method avoids the long steady-state wait to trigger the optimizations, it adds extra complexity to the RTO project by including the requirement of developing a rigorous dynamic model, which can hinder the industrial-scale applicability of the methodology. To overcome this requirement, a Hammerstein dynamic approximation model has been proposed to replace the rigorous dynamic model in a Hammerstein ROPA (HROPA) framework. Previous work has demonstrated that the proposed model is adequate for use in RTO since it preserves the parameter observability property of the static model. In this paper, two HROPA approaches are implemented in an experimental rig and compared to a previously implemented ROPA approach. The experimental results confirmed that HROPA presents a similar economic performance to ROPA with much less effort required in the modeling stage. Finally, a comprehensive literature review of the topic is presented, and general guidelines for the Hammerstein dynamic matrix identification are provided.
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•Literature review on the use of transient measurement in static RTO approaches.•Proof of concept Hammerstein ROPA in a lab-scale experiment rig.•Increased applicability of ROPA-like algorithms in large-scale industrial systems.•Guidelines for the Hammerstein dynamic matrix identification in practice.•Use of the static model directly in the dynamic model adaptation algorithm.
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