Novel Formulation and Application of Model Predictive Control.

Model predictive control (MPC) has been extensively studied in academia and widely accepted in industry. This research has focused on the novel formulation of model predictive controllers for systems that can be decomposed according to their nonlinearity properties and several novel MPC applications including bioreactors modeled by population balance equations (PBE), gas pipeline networks, and cryogenic distillation columns. Two applications from air separation industries are studied. A representative gas pipeline network is modeled based on first principles. The full-order model is ill-conditioned, and reduced-order models are constructed using time-scale decomposition arguments. A linear model predictive control (LMPC) strategy is then developed based on the reduced-order model. The second application is a cryogenic distillation column. A low-order dynamic model based on nonlinear wave theory is developed by tracking the movement of the wave front. The low-order model is compared to a first-principles model developed with the commercial simulator HYSYS.Plant. On-line model adaptation is proposed to overcome the most restrictive modeling assumption. Extensions for multiple column modeling and nonlinear model predictive control (NMPC) also are discussed. The third application is a continuous yeast bioreactor. The autonomous oscillations phenomenon is modeled by coupling PBE model of the cell mass distribution to the rate limiting substrate mass balance. A controller design model is obtained by linearizing and temporally discretizing the ODES derived from spatial discretization of the PBE model. The MPC controller regulate the discretized cell number distribution by manipulating the dilution rate and the feed substrate concentration. A novel plant-wide control strategy is developed based on integration of LMPC and NMPC. It is motivated by the fact that most plants that can be decomposed into approximately linear subsystems and highly nonlinear subsystems. LMPCs and NMPCs are applied to the respective subsystems. A sequential solution algorithm is developed to minimize the amount of unknown information in the MPC design. Three coordination approaches are developed to reduce the amount of information unavailable due to the sequential MPC solution of the coupled subsystems and applied to a reaction/separation process. Furthermore, a multi-rate approach is developed to exploit time-scale differences in the subsystems

Linear optical quantum computation with imperfect entangled photon-pair sources and inefficient non-photon-number-resolving detectors

We propose a scheme for efficient cluster state quantum computation by using imperfect polarization-entangled photon-pair sources, linear optical elements and inefficient non-photon-number-resolving detectors. The efficiency threshold for loss tolerance in our scheme requires the product of source and detector efficiencies should be >1/2 - the best known figure. This figure applies to uncorrelated loss. We further find that the loss threshold is unaffected by correlated loss in the photon pair source. Our approach sheds new light on efficient linear optical quantum computation with imperfect experimental conditions.Comment: 5 pages, 2 figure

The Functions of Non-coding RNAs in rRNA Regulation

Ribosomes are ribonucleoprotein machines that decode the genetic information embedded in mRNAs into polypeptides. Ribosome biogenesis is tightly coordinated and controlled from the transcription of pre-rRNAs to the assembly of ribosomes. Defects or disorders in rRNA production result in a number of human ribosomopathy diseases. During the processes of rRNA synthesis, non-coding RNAs, especially snoRNAs, play important roles in pre-rRNA transcription, processing, and maturation. Recent research has started to reveal that other long and short non-coding RNAs, including risiRNA, LoNA, and SLERT (among others), are also involved in pre-rRNA transcription and rRNA production. Here, we summarize the current understanding of the mechanisms of non-coding RNA-mediated rRNA generation and regulation and their biological roles

catena-Poly[diaqua­tris(μ3-biphenyl-2,2-dicarboxyl­ato)disamarium(III)]

The title compound, [Sm2(C14H8O4)3(H2O)2]n, is composed of one-dimensional chains and is isostructural with previously reported compounds [Wang et al. (2003 ▶). Eur. J. Inorg. Chem. pp. 1355–1360]. The asymmetric unit contains two Sm atoms, each of which lies on a crystallographic twofold axis. Both crystallographically independent Sm atoms are coordinated by eight O atoms in a distorted dodeca­hedral arrangement. The polymeric chains run along [001]. Adjacent chains are connected through π–π inter­actions [centroid–centroid distance = 3.450 (2) Å], forming a two-dimensional supra­molecular network

Poly[[tetra­aqua­bis[μ4-2,2′-(p-phenyl­ene­di­oxy)diacetato][μ2-2,2′-(p-phenyl­ene­di­oxy)diacetato]dierbium(III)] hexa­hydrate]

The asymmetric unit of the title compound, [Er2(C10H8O6)3(H2O)4]·6H2O, comprises one Er3+ ion, one and a half 2,2′-(p-phenyl­enedi­oxy)diacetate (hqda) ligands, two coordinated water mol­ecules and three uncoordinated water mol­ecules. The Er3+ ion is nine-coordinated by seven O atoms from hqda ligands and two O atoms from water mol­ecules. In the title compound, there are two types of crystallographically independent ligands: one with an inversion center in the middle of the ligand is chelating on both ends of the ligand towards each one Er center; the other hqda ligands are bridging-chelating on one side, and bridging on the other end of the ligand. Two adjacent Er3+ ions are thus chelated and bridged by –COO groups from hqda ligands in three coordination modes (briding–chelating, bridging and chelating). These building blocks are linked by OOC—CH2O—C6H4—OCH2—COO spacers, forming two-dimensional neutral layers. Adjacent layers are linked by O—H⋯O hydrogen-bonding inter­actions, forming a three-dimensional supermolecular network

Poly[tetra­aquadi-μ4-oxalato-lutetium(III)potassium]

In the title compound, [KLu(C2O4)2(H2O)4]n, the LuIII ion lies on a site of symmetry in a dodeca­hedron defined by eight O atoms from four oxalate ligands. The K atom lies on another site of the same symmetry and is coordinated by four oxalate O atoms and four O water atoms. The mid-point of the C—C bond of the oxalate group lies on an inversion center. In the packing structure, each oxalate ligand links two Lu(III) and two K atoms, forming a three-dimensional open framework with channels running along [001]. Inter­molecular O—H⋯O hydrogen bonds occur

Factors Influencing the Perception of Seller Credibility in Online Reputation System: an Eye-Movement Approach

The current online reputation systems for online sellers face great challenges from bad-faith behavior such as malicious negative reviews, click farming, mismatch between images and commodities, and forged commodities. To optimize the design of online reputation systems, explore the consumer utilization of credit clues, and describe the law of mutual trust, this paper puts forth three hypotheses about the influencing factors of consumer perception of online seller credibility and integrates various research methods such as an eye-movement experiment, questionnaire survey, econometric analysis, and empirical research. To evaluate the three hypotheses, the display modes of commodities on a current e-commerce platform were optimized, and eye-movement experiments were conducted on original and optimized webpages. Results show that the display of sales growth, the refinement and tagging of review content significantly impacted consumer perception of seller credibility. Further, designers of online reputation systems were advised to display sales trends, provide personalized sales queries, and tag a variety of reviews for consumers to easily ascertain credible sellers. This advice helped curb bad-faith behavior

The First Sinomastodon (Gomphotheriidae, Proboscidea) Skull From the Quaternary in China

The first Sinomastodon (Gomphotheriidae, Proboscidea) skull of the Early Pleistocene, collected from the Renzidong Cave deposits in Anhui Province, Eastern China, is described here as S. jiangnanensis sp. nov. As the only brevirostrine trilophodont gomphotheriid known from the Old World, Sinomastodon was mainly indigenous to China from the Early Pliocene to the Pleistocene. Compared with a few single Pleistocene teeth previously found in China, S. jiangnanensis sp. nov. is represented by a relatively complete skull, mandible and dentition, which is the first discovery of a Quaternary Sinomastodon skull from China. With a brevirostrine, elephant-like skull, no lower tusks, and simple bunodont and trilophodont intermediate molars, the new species is morphologically distinct from other gomphotheres and should belong to the genus Sinomastodon. The new species is more progressive than S. hanjiangensis and the Pliocene type species S. intermedius in its skull and mandible morphology, but is evidently more primitive than the Pleistocene S. yangziensis in its molar morphology. The faunal analysis suggests that the emergence of S. jiangnanensis sp. nov. in Jiangnan area and its southward migration may have been related to a cooling event at the beginning of the Quaternary in Eastern China

The First Sinomastodon (Gomphotheriidae, Proboscidea) Skull From the Quaternary in China

The first Sinomastodon (Gomphotheriidae, Proboscidea) skull of the Early Pleistocene, collected from the Renzidong Cave deposits in Anhui Province, Eastern China, is described here as S. jiangnanensis sp. nov. As the only brevirostrine trilophodont gomphotheriid known from the Old World, Sinomastodon was mainly indigenous to China from the Early Pliocene to the Pleistocene. Compared with a few single Pleistocene teeth previously found in China, S. jiangnanensis sp. nov. is represented by a relatively complete skull, mandible and dentition, which is the first discovery of a Quaternary Sinomastodon skull from China. With a brevirostrine, elephant-like skull, no lower tusks, and simple bunodont and trilophodont intermediate molars, the new species is morphologically distinct from other gomphotheres and should belong to the genus Sinomastodon. The new species is more progressive than S. hanjiangensis and the Pliocene type species S. intermedius in its skull and mandible morphology, but is evidently more primitive than the Pleistocene S. yangziensis in its molar morphology. The faunal analysis suggests that the emergence of S. jiangnanensis sp. nov. in Jiangnan area and its southward migration may have been related to a cooling event at the beginning of the Quaternary in Eastern China