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Global Optimization of Nonlinear Blend-Scheduling Problems

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Engineering 2017年第2期3卷 188-201页

作者： pedro A.Castillo Castillo pedro M.Castro Vladimir Mahalec Department of Chemical Engineering McMaster UniversityHamiltonON L8S 4L8Canada Center for Mathematics Fundamental Applications and Operations ResearchFaculty of SciencesUniversity of LisbonLisbon 1749-016Portugal

The scheduling of gasoline-blending operations is an important problem in the oil refining industry. Thisproblem not only exhibits the combinatorial nature that is intrinsic to scheduling problems, but alsonon-convex nonlinear behavior, due to the blending of various materials with different quality *** this work, a global optimization algorithm is proposed to solve a previously published continuous-timemixed-integer nonlinear scheduling model for gasoline blending. The model includes blend recipe optimi-zation, the distribution problem, and several important operational features and constraints. The algorithmemploys piecewise McCormick relaxation （PMCR） and normalized multiparametric disaggregation tech-nique （NMDT） to compute estimates of the global optimum. These techniques partition the domain of oneof the variables in a bilinear term and generate convex relaxations for each partition. By increasing the num-ber of partitions and reducing the domain of the variables, the algorithm is able to refine the estimates ofthe global solution. The algorithm is compared to two commercial global solvers and two heuristic methodsby solving four examples from the literature. Results show that the proposed global optimization algorithmperforms on par with commercial solvers but is not as fast as heuristic approaches.

关键词： Global optimization Nonlinear gasoline blending Continuous-time scheduling model Piecewise linear relaxations

Kinetic behaviour of commercial catalysts for methane reforming in ethanol steam reforming process

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Journal of Energy Chemistry 2014年第5期23卷 639-644页

作者： Jorge Vicente Javier Erea Martin Olazar pedro l.Benito Javier Bilbao Ana G.Gayubo Departamento de Ingeniería Química Universidad del País Vasco UPV/EHU Apartado 644 48080 Bilbao Spain Departamento de Ingeniería Minera y Metalúrgica y Ciencia de los Materiales Universidad del País Vasco UPV/EHUNieves Cano 12 01006 Vitoria-Gasteiz Spain

Ethanol steam reforming has been studied in a fluidized bed （in order to ensure bed isothermicity） on commercial catalysts for methane reforming. The results allow analyzing the effect of temperature （in 300-700℃ range）, and both metal and support nature on the reaction indices （ethanol conversion, yields and selectivities to H2 and byproducts （CO2, CO, CH4 and C2H4O））. Special attention has been paid to catalysts＇ stability by comparing the evolution of the reaction indices with time on stream at 500°C （minimum CO formation） and 700℃ （minimum deactivation by coke deposition）. Although they provide a slightly lower H2 yield, the results evidence a good behaviour of Ni based catalysts, indicating that they are an interesting alternative of more expensive Rh based ones.

关键词： ethanol steam reforming hydrogen commercial catalyst selectivity deactivation

Deadly oasis:Recurrent annihilation of Cretaceous desert bryophyte colonies;the role of solar,climate and lithospheric forcing

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Geoscience Frontiers 2021年第1期12卷 1-12页

作者： Juan pedro Rodríguez-lópeza Eduardo Barrón Daniel Peyrot Gary B.Hughes Department of Geology.Faculty of Science.United Arab Emirates University.50009.Al Ain Abu DhabiUnited Arab Emirates Instituto Geológico y Minero de Espana(IGME) Ríos Rosas 23E-28003MadridSpain School of Earth and Environment University of Western Australia.6101CrawleyWestern AustraliaAustralia Centre for Energy Geosciences University of Western Australia.6101CrawleyWestern AustraliaAustralia Physics Department University of CaliforniaSanta BarbaraCA93106USA

Many oases(wet interdunes)are sedimentary systems characterized by high-frequency water-level oscillations,marked changes in salinity and intense biological activity at their *** are considered to be one of the most challenging environments on Earth for ecosystem *** dynamic,depositional settings are usually unfavourable for fossilization and subsequent preservation of vegetal *** paper describes bryophyte(liverwort)assemblages occurring in three successive horizons interpreted to represent(i)recurrent early successional phases of biological soil crust colonization of wet interdune margins or(ii)exceptional preservation of floating or riparian liverworts in oasis pond waters associated with a progressive fall of the interdune water *** record of in situ colonization surfaces characterized by delicate(***-free)three-dimensional structures represents an exceptional type of preservation herein associated with a rapid variation in phreatic interdune water level and the subsequent establishment of anoxic and reducing *** occurrence of exceptionally preserved liverwort colonies coincides with the sedimentary record of,at least,three seismite levels in the *** gathered from the site suggests that the water table of the oasis was controlled by a combination of(i)a positive creation of accommodation space due to subsidence associated with movement on syn-sedimentary extensional faults,and(ii)the rise and fall of the oasis water table controlled by the oscillations of the groundwater system due to orbital changes which appear to drive the variability of the climate *** groundwater levels flooded the oasis soil crusts and lead to the exceptional recurrent preservation of liverwort colonies at the oasis ***,considering the hypothesis of floating or riparian liverworts in the oasis pond waters,the fall in the level of the oasis water table placed the floating liverworts in contact with the

关键词： Oasis Cretaceous liverworts Colonies Extensional tectonics Solar cyclicity

Multi-terminal DC grids: challenges and prospects

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Journal of Modern Power Systems and Clean Energy 2017年第4期5卷 515-523页

作者： pedro RODRIGUEZ Kumars ROUZBEHI loyola University Andalucia Seville Spain

A few multi-terminal direct current(MTDC)systems are in operation around the world today. However,MTDC grids overlaying their AC counterpart might a reality in a near future. The main drivers for constructing such direct current grids are the large-scale integration of remote renewable energy resources into the existing alternative current(AC) grids, and the promotion and development of international energy markets through the socalled supergrids. This paper presents the most critical challenges and prospects for such emerging MTDC grids,along with a foreseeable technology development roadmap,with a particular focus on crucial control and operational issues that are associated with MTDC systems and grids.

关键词： HVDC systems MTDC grids Control and operation Integration of renewable energies Supergrid

The RNA Modification N^6-methyladenosine and Its Implications in Human Disease

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Genomics, Proteomics & Bioinformatics 2017年第3期15卷 154-163页

作者： pedro J.Batista laboratory of Cell Biology Center for Cancer ResearchNational Cancer InstituteNational Institutes of HealthBethesda MD 20892USA

Impaired gene regulation lies at the heart of many disorders, including developmental diseases and cancer. Furthermore, the molecular pathways that control gene expression are often the target of cellular parasites, such as viruses. Gene expression is controlled through multiple mechanisms that are coordinated to ensure the proper and timely expression of each gene. Many of these mechanisms target the life cycle of the RNA molecule, from transcription to translation. Recently, another layer of regulation at the RNA level involving RNA modifications has gained renewed interest of the scientific community. The discovery that N6-methyladenosine （m6A）, a mod- ification present in mRNAs and long noncoding RNAs, can be removed by the activity of RNA demethylases, launched the field of epitranscriptomics; the study of how RNA function is regulated through the addition or removal of post-transcriptional modifications, similar to strategies used to regulate gene expression at the DNA and protein level. The abundance of RNA post-transcriptional modifications is determined by the activity of writer complexes （methylase） and eraser （RNA demethylase） proteins. Subsequently, the effects of RNA modifications materialize as changes in RNA structure and/or modulation of interactions between the modified RNA and RNA binding proteins or regulatory RNAs. Disruption of these pathways impairs gene expression and cellular function. This review focuses on the links between the RNA modification m6A and its implications in human diseases.

关键词： N6-methyladenosine Epitranscriptomics Cancer Viral replication Metabolic disease

Integrated Groups and Smooth Distribution Groups

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Acta Mathematica Sinica,English Series 2007年第1期23卷 57-64页

作者： pedro J.MIANA Departamento de Matemáticas Universidad de Zaragoza50009Spain

In this paper, we prove directly that α-times integrated groups define algebra homomorphisms. We also give a theorem of equivalence between smooth distribution groups and α-times integrated groups.

关键词： integrated groups distribution groups Weyl fractional calculus

Influence of bed elevation discordance on flow patterns and head losses in an open-channel confluence

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Water Science and Engineering 2019年第3期12卷 235-243页

作者： pedro Xavier Ramos laurent Schindfessel Joao pedro Pego Tom De Mulder Department of Civil Engineering Ghent University Ghent 9000 Belgium Faculty of Engineering University of Porto Porto 4200-465 Portugal

Confluences play a major role in the dynamics of networks of natural and man-made open channels, and field measurements on river confluences reveal that discordance in bed elevation is *** of schematized confluences with a step at the interface between the tributary and the main channel bed reveal that bed elevation discordance is an important additional control for the confluence *** study aimed to improve understanding of the influence of bed elevation discordance on the flow patterns and head losses in a right-angled confluence of an open channel with rectangular cross-sections.A large eddy simulation (lES)-based numerical model was set up and validated with experiments by *** configurations with different bed discordance ratios were *** results confirm that, with increasing bed elevation discordance, the tributary streamlines at the confluence interface deviate less from the geometrical confluence angle, the extent of the recirculation zone (RZ) gets smaller, the ratio of the water depth upstream to that downstream of the confluence decreases, and the water level depression *** bed elevation discordance also leads to the development of a large-scale structure in the lee of the *** the appearance of the large-scale structure, the reduced extent of the RZ and associated changes in flow deflection/contraction reduce total head losses experienced by the main channel with an increase of the bed discordance *** turns out that bed elevation discordance converts the lateral momentum from the tributary to streamwise momentum in the main channel more efficiently.

关键词： Open channel confluence Bed elevation discordance Three-dimensional numerical modelling large eddy simulation Recirculation zone

Web-based system for training and dissemination of a magnification chromoendoscopy classification

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World Journal of Gastroenterology 2008年第46期14卷 7086-7092页

作者： Mário Jorge Dinis-Ribeiro Ricardo Cruz Correia Cristina Santos Sónia Fernandes Ernesto Palhares Rui almeida Silva pedro Amaro Miguel Areia Altamiro Costa-Pereira luis Moreira-Dias Gastroenterology Department Portuguese Oncology Institute Center for Research in Information Systems and Health Technologies (CINTESIS)/Department of Biostatistics and Medical Informatics Porto Faculty of Medicine Gastroenterology Department Coimbra University Hospital

AIM： To evaluate the use of web-based technologies to assess the learning curve and reassess reproducibility of a simplified version of a classification for gastric magnification chromoendoscopy （MC）. METHODS： As part of a multicenter trial, a hybrid approach was taken using a CD-ROM, with 20 films of MC lasting 5 s each and an ＂autorun＂ file triggering a local HTMl frameset referenced to a remote questionnaire through an Internet connection. Three endoscopists were asked to prospectively and independently classify 10 of these films randomly selected with at least 3 d apart. The answers were centrally stored and returned to participants together with adequate feedback with the right answer. RESUlTS： For classification in 3 groups, both intra- [Cohen＇s kappa （K） = 0.79-1.00 to 0.89-1.00] and inter-observer agreement increased from 1st （moderate） to 6th observation （k = 0.94）. Also, agreement with reference increased in the last observations （0.90, 1.00 and 1.00, for observers A, B and C, respectively）. Validity of 100% was obtained by all observers at their 4th observation. When a 4th （sub）group was considered, inter-observer agreement was almost perfect （K = 0.92） at 6th observation. The relation with reference clearly improved into K （0.93-1.00） and sensitivity （75%-100%） at their 6th observations. CONClUSION： This MC classification seems to be easily explainable and learnable as shown by excellent intra- and inter-observer agreement, and improved agreement with reference. A web system such as the one used in this study may be useful for endoscopic or other image based diagnostic procedures with respect to definition, education and dissemination.

关键词： Magnification Chromoendoscopy Reproducibility learning curve

Usability perceptions and beliefs about smart thermostats by chi-square test, signal detection theory, and fuzzy detection theory in regions of Mexico

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Frontiers in Energy 2019年第3期13卷 522-538页

作者： pedro PONCE Therese PEFFER Arturo MOlINA Tecnologico de Monterrey calle del puente 222 MexicoMexico CityNon-US/Non-Canadian 64849Mexico California Institute for Energy and Environment University of California BerkeleyBerkeleyCA 94720USA

It is well known that smart thermostats (STs) have become key devices in the implementation of smart homes;thus, they are considered as primary elements for the control of electrical energy consumption in households. Moreover, energy consumption is drastically affected when the end users select unsuitable STs or when they do not use the STs correctly. Furthermore, in future, Mexico will face serious electrical energy challenges that can be considerably resolved if the end users operate the STs in a correct manner. Hence, it is important to carry out an in-depth study and analysis on thermostats, by focusing on social aspects that influence the technological use and performance of the thermostats. This paper proposes the use of a signal detection theory (SDT), fuzzy detection theory (FDT), and chi-square (CS) test in order to understand the perceptions and beliefs of end users about the use of STs in Mexico. This paper extensively shows the perceptions and beliefs about the selected thermostats in Mexico. Besides, it presents an in-depth discussion on the cognitive perceptions and beliefs of end users. Moreover, it shows why the expectations of the end users about STs are not met. It also promotes the technological and social development of STs such that they are relatively more accepted in complex electrical grids such as smart grids.

关键词： thermostats perceptions beliefs signal detection theory (SDT) fuzzy signal detection theory (FSDT) chi-square (CS) test