Performance monitoring of MPC based on dynamic principal component analysis

A unified framework based on the dynamic principal component analysis (PCA) is proposed for performance monitoring of constrained multi-variable model predictive control (MPC) systems. In the proposed performance monitoring framework, the dynamic PCA based performance benchmark is adopted for performance assessment, while performance diagnosis is carried out using a unified weighted dynamic PCA similarity measure. Simulation results obtained from the case study of the Shell process demonstrate that the use of the dynamic PCA performance benchmark can detect the performance deterioration more quickly compared with the traditional PCA method, and the proposed unified weighted dynamic PCA similarity measure can correctly locate the root cause for poor performance of MPC controller

A data-based approach for multivariate model predictive control performance monitoring

An intelligent statistical approach is proposed for monitoring the performance of multivariate model predictive control (MPC) controller, which systematically integrates both the assessment and diagnosis procedures. Model predictive error is included into the monitored variable set and a 2-norm based covariance benchmark is presented. By comparing the data of a monitored operational period with the "golden" user-predefined one, this method can properly evaluate the performance of an MPC controller at the monitored operational stage. Characteristic direction information is mined from the operating data and the corresponding classes are built. The eigenvector angle is defined to describe the similarity between the current data set and the established classes, and an angle-based classifier is introduced to identify the root cause of MPC performance degradation when a poor performance is detected. The effectiveness of the proposed methodology is demonstrated in a case study of the Wood–Berry distillation column system

A narrative review on the applications of intracavitary contrast-enhanced ultrasonography in pediatric lower genitourinary anomalies

PurposeWe mainly aimed to perform a narrative review of clinical applications of the three intracavitary contrast-enhanced ultrasonography (CEUS) including contrast-enhanced voiding urosonography (ceVUS), contrast-enhanced retrograde urethrosonography (ceRUG), and contrast-enhanced genitosonography (ceGS) in pediatric lower genitourinary anomalies.MethodA literature search in the PubMed and Web of Science databases was conducted up to 1 July 2022 on all studies published in English using the search terms “contrast-enhanced voiding urosonography”, “contrast-enhanced retrograde urethrosonography”, and “contrast-enhanced genitosonography”. Trials were limited to pediatric subjects (ages ≤18 years) with no time restrictions. The inclusion criteria were studies on ceVUS, ceRUG, and ceGS to evaluate pediatric lower genitourinary anomalies. Two independent authors summarized the included articles.ResultsFinally, a total of 48 original articles and 6 case reports or case series were included, of which 50 (93%) were only relevant to ceVUS, 3 (5%) articles involved ceGS, while only one (2%) article involved ceRUG, and 87% of the applications of ceVUS were focused on vesicoureteral reflux (VUR). We also searched 24 related reviews, of which 20 involved ceVUS in diagnosing VUR and 4 involved ceRUG and ceGS for other lower genitourinary anomalies.ConclusionIntracavitary CEUS including ceVUS, ceRUG, and ceGS in pediatrics has many advantages over other radiological examinations in diagnosing lower genitourinary anomalies. Although ceVUS is widely used in detecting VUR, ceRUG and ceGS have also become promising techniques for evaluating the urethral pathologies and urogenital sinus

Crystal-Plane-Dependent Activity of Spinel Co3O4 Towards Water Splitting and the Oxygen Reduction Reaction

Insights into the relationship between the crystal planes of metal oxides and the catalytic activity of the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER) are essential for developing efficient renewable energy technologies. Herein, spinel Co3O4 nanomaterials were synthesized controllably with the specified morphologies of nanocubes, nanosheets, and nanoplates with different exposed planes of {100}, {110}, and {111}, respectively. The effects of the crystal planes of Co3O4 on the activity for the OER, ORR, and HER were subsequently investigated in alkaline media. Different electrocatalytic performances are possibly attributed to the abundance ratios of Co3+/Co2+ over the different exposed planes. The surface Co3+ ions exhibit higher activity for the OER and HER, whereas the surface Co2+ ions exhibit better performance for the ORR; moreover, higher electroconductivity enhances the polarization current for ORR and HER except OER

Cycles of fine-grained sedimentation and their influences on organic matter distribution in the second member of Paleogene Kongdian Formation in Cangdong Sag, Bohai Bay Basin, East China

According to the theory of sequence stratigraphy based on continental transgressive-regressive (T-R) cycles, a 500 m continuous core taken from the second member of Kongdian Formation (Kong 2 Member) of Paleogene in Well G108-8 in the Cangdong Sag, Bohai Bay Basin, was tested and analyzed to clarify the high-frequency cycles of deep-water fine-grained sedimentary rocks in lacustrine basins. A logging vectorgraph in red pattern was plotted, and then a sequence stratigraphic framework with five-order high-frequency cycles was formed for the fine-grained sedimentary rocks in the Kong 2 Member. The high-frequency cycles of fine-grained sedimentary rocks were characterized by using different methods and at different scales. It is found that the fifth-order T cycles record a high content of terrigenous clastic minerals, a low paleosalinity, a relatively humid paleoclimate and a high density of laminae, while the fifth-order R cycles display a high content of carbonate minerals, a high paleosalinity, a dry paleoclimate and a low density of laminae. The changes in high-frequency cycles controlled the abundance and type of organic matter. The T cycles exhibit relatively high TOC and abundant endogenous organic matters in water in addition to terrigenous organic matters, implying a high primary productivity of lake for the generation and enrichment of shale oil