Fractional transformation-based decentralized robust control of a coupled-tank system for industrial applications

Petrochemical and dairy industries, waste management, and paper manufacturing fall under the category of process industries where flow and liquid control are essential. Even when liquids are mixed or chemically treated in interconnected tanks, the fluid and flow should constantly be observed and controlled, especially when dealing with nonlinearity and imperfect plant models. In this study, we propose a nonlinear dynamic multiple-input multiple-output (MIMO) plant model. This model is then transformed through linearization, a technique frequently utilized in the analysis and modeling of fractional processes, and decoupling for decentralized fixed-structure H-infinity robust control design. Simulation tests based on MATLAB and SIMULINK are subsequently executed. Numerous assessments are conducted to evaluate tracking performance, external disturbance re jection, and plant parameter fluctuations to gauge the effectiveness of the proposed model. The objective of this work is to provide a framework that anticipates potential outcomes, paving the way for implementing a reliable controller synthesis for MIMO-connected tanks in real-world scenarios.This research was partially funded by FONDECYT grant number 1200525 (V.L.) from the National Agency for Research and Development (ANID) of the Chilean government under the Ministry of Science, Technology, Knowledge, and Innovation; and by Portuguese funds through the CMAT—Research Centre of Mathematics of University of Minho—within projects UIDB/00013/2020 and UIDP/00013/2020 (C.C.)

Actuation System Design Optimization for Lower Limb Assistive Robotic Exoskeletons

Assistive lower limb robotic exoskeletons are wearable devices that support people with impaired gaits to perform activities of daily living (ADL) independently. The rapid increase in the mobility disorders in the growing population has a significant impact on the demand of wearable devices. Consequently, the requirement to develop efficient wearable devices that meet the needs of the users has increased. This study is oriented towards developing lightweight, power efficient and powerful assistive robotic exoskeletons with a focus on the actuation aspect. An analysis of the gait pathologies among different categories of patients reveals a significant difference in the spatio-temporal, kinematic and kinetic requirements of the impaired gait subjects as compared to the healthy users. Therefore, suitable powered assistive devices have to be developed to address the demand of the users. Following the assessment of the support requirements of the users, the number of degrees of freedom of the device was identified to evaluate an actuator design solution to determine an optimal motor size and transmission mechanism for a rigid actuation system. Part of this study also includes the elastic actuators that were used in two basic configurations as series and parallel elastic configurations. Elastic element was introduced into the system to reduce the power flow requirements of the actuation system. It was beneficial for the reduction of the actuator size and to increase the efficiency of the system. The spring optimization techniques were explored that lead to a decrease in the kinetic requirements of the system. The analysis showed that a parallel elastic actuator (PEA) was able to reduce significant amount of the power requirements of the system, while series elastic actuator (SEA) has a marginal impact on the overall efficiency of the system. An actuator design solution was developed for the elastic actuators to determine an ideal solution for the motor and transmission mechanism for an elastic actuation system. Furthermore, the redundancy of an actuation system was also analysed in which the output power of the system is distributed between the two motors. The redundant rigid and elastic systems were investigated. The benefits of an elastic system as a variable stiffness actuator in a dual arrangement were assessed. An optimized design solution for a dual system was developed to evaluate an optimal dual actuation system for a rigid and elastic system. Based on the outcomes of the actuator design solutions for a rigid and elastic systems in a single and dual arrangements, the optimal actuation systems were implemented and validated using a virtual prototype of an assistive robotic exoskeleton

Social network visualization as a contract tracing tool

Something many pathogens have in common is the requirement for tracing their spread under harsh time constraints, posing a so-called contact tracing (or ``race-to-trace'') problem. We present a tool for visualizing contact networks, an important step towards practical use by epidemiologists, which generates interactive three-dimensional (3D) network visualizations. Its general purpose visualization engine can support multiple applications and varying pathogens. The main purpose is to trace, in the case of an outbreak, contacts among individuals known to have been at the same place

Improved Photocatalytic and Antioxidant Activity of Olive Fruit Extract-Mediated ZnO Nanoparticles

Photodegradation is an efficient strategy for the removal of organic pollutants from wastewater. Due to their distinct properties and extensive applications, semiconductor nanoparticles have emerged as promising photocatalysts. In this work, olive (Olea Europeae) fruit extract-based zinc oxide nanoparticles (ZnO@OFE NPs) were successfully biosynthesized using a one-pot sustainable method. The prepared ZnO NPs were systematically characterized using UV-Vis, FTIR, SEM, EDX and XRD and their photocatalytic and antioxidant activity was evaluated. SEM demonstrated the formation of spheroidal nanostructures (57 nm) of ZnO@OFE and the EDX analysis confirmed its composition. FTIR suggested the modification/capping of the NPs with functional groups of phytochemicals from the extract. The sharp XRD reflections revealed the crystalline nature of the pure ZnO NPs with the most stable hexagonal wurtzite phase. The photocatalytic activity of the synthesized catalysts was evaluated by measuring the degradation of methylene blue (MB) and methyl orange (MO) dyes under sunlight irradiation. Improved degradation efficiencies of 75% and 87% were achieved within only 180 min with photodegradation rate constant k of 0.008 and 0.013 min−1 for MB and MO, respectively. The mechanism of degradation was proposed. Additionally, ZnO@OFE NPs exhibited potent antioxidant activity against DPPH, hydroxyl, peroxide and superoxide radicals. Hence, ZnO@OFE NPs may have potential as a cost-effective and green photocatalyst for wastewater treatment

Association of the 9p21.3 locus with risk of first-ever myocardial infarction in Pakistanis: Case-control study in South Asia and updated meta-analysis of Europeans

Objective: To examine variants at the 9p21 locus in a case-control study of acute myocardial infarction (MI) in Pakistanis and to perform an updated meta-analysis of published studies in people of European ancestry.Methods and results: A total of 1851 patients with first-ever confirmed MI and 1903 controls were genotyped for 89 tagging single-nucleotide polymorphisms at locus 9p21, including the lead variant (rs1333049) identified by the Wellcome Trust Case Control Consortium. Minor allele frequencies and extent of linkage disequilibrium observed in Pakistanis were broadly similar to those seen in Europeans. In the Pakistani study, 6 variants were associated with MI (P\u3c10(-2)) in the initial sample set, and in an additional 741 cases and 674 controls in whom further genotyping was performed for these variants. For Pakistanis, the odds ratio for MI was 1.13 (95% CI, 1.05 to 1.22; P=2 x 10(-3)) for each copy of the C allele at rs1333049. In comparison, a meta-analysis of studies in Europeans yielded an odds ratio of 1.31 (95% CI, 1.26 to 1.37) for the same variant (P=1 x 10(-3) for heterogeneity). Meta-analyses of 23 variants, in up to 38,250 cases and 84,820 controls generally yielded higher values in Europeans than in Pakistanis.Conclusions: To our knowledge, this study provides the first demonstration that variants at the 9p21 locus are significantly associated with MI risk in Pakistanis. However, association signals at this locus were weaker in Pakistanis than those in European studies

Genetic determinants of major blood lipids in Pakistanis compared with Europeans.

BACKGROUND: Evidence is sparse about the genetic determinants of major lipids in Pakistanis. METHODS AND RESULTS: Variants (n=45 000) across 2000 genes were assessed in 3200 Pakistanis and compared with 2450 Germans using the same gene array and similar lipid assays. We also did a meta-analysis of selected lipid-related variants in Europeans. Pakistani genetic architecture was distinct from that of several ethnic groups represented in international reference samples. Forty-one variants at 14 loci were significantly associated with levels of HDL-C, triglyceride, or LDL-C. The most significant lipid-related variants identified among Pakistanis corresponded to genes previously shown to be relevant to Europeans, such as CETP associated with HDL-C levels (rs711752; P<10(-13)), APOA5/ZNF259 (rs651821; P<10(-13)) and GCKR (rs1260326; P<10(-13)) with triglyceride levels; and CELSR2 variants with LDL-C levels (rs646776; P<10(-9)). For Pakistanis, these 41 variants explained 6.2%, 7.1%, and 0.9% of the variation in HDL-C, triglyceride, and LDL-C, respectively. Compared with Europeans, the allele frequency of rs662799 in APOA5 among Pakistanis was higher and its impact on triglyceride concentration was greater (P-value for difference <10(-4)). CONCLUSIONS: Several lipid-related genetic variants are common to Pakistanis and Europeans, though they explain only a modest proportion of population variation in lipid concentration. Allelic frequencies and effect sizes of lipid-related variants can differ between Pakistanis and Europeans