Distributed model predictive control of an experimental four-tank system

A distributed model predictive control (DMPC) framework is proposed. The physical plant structure and the plant mathematical model are used to partition the system into self-sufficient estimation and control nodes. Local measurements at the nodes are used to estimate the relevant plant states. This information is then used in the model predictive control calculations. Communication among relevant nodes during estimation and control calculations provides improvement over the performance of completely decentralized controllers. The DMPC framework is demonstrated for the level control of an experimental four-tank system. The performance of the DMPC system for disturbance rejection is compared with other control configurations. The results indicate that the proposed framework provides significant improvement over completely decentralized MPC controllers, and approaches the performance of a fully centralized design.     

Analysis of immobilised multi-enzyme reaction systems with Michaelis-Menten kinetics

The consecutive sequence of reactions S → P₁ → P₂ taking place inside a permeable spherical particle is analysed for the case in which the enzyme-catalysed steps in the reaction follow Michaelis-Menten type kinetics. The case in which each step in the reaction is inhibited by its product is also considered. The theoretical analysis takes into account both interparticle and intraparticle diffusional limitations and utilises an orthogonal collocation technique to obtain the effectiveness factor and selectivity of the reaction sequence. The orthogonal collocation method is found to be both convenient and simple and the analysis should prove useful in the design of immobilised multi-enzyme reactors.     

Implementation of an 8-Core, 64-Thread, Power-Efficient SPARC Server on a Chip

The second in the Niagara series of processors (Niagara2) from Sun Microsystems is based on the power-efficient chip multi-threading (CMT) architecture optimized for Space, Watts (Power), and Performance (SWaP) [SWap Rating = Performance/(Space _* Power) ]. It doubles the throughput performance and performance/watt, and provides >10times improvement in floating point throughput performance as compared to UltraSPARC T1 (Niagara1). There are two 10 Gb Ethernet ports on chip. Niagara2 has eight SPARC cores, each supporting concurrent execution of eight threads for 64 threads total. Each SPARC core has a floating point and graphics unit and an advanced cryptographic unit which provides high enough bandwidth to run the two 10 Gb Ethernet ports encrypted at wire speeds. There is a 4 MB Level2 cache on chip. Each of the four on-chip memory controllers controls two FBDIMM channels. Niagara2 has 503 million transistors on a 342 mm² die packaged in a flip-chip glass ceramic package with 1831 pins. The chip is built in Texas Instruments' 65 nm 11LM triple-Vt CMOS process. It operates at 1.4 GHz at 1.1 V and consumes 84 W.     

Drift and retention of pelagic spawning minnow eggs in a regulated river

Long‐distance drift of eggs and larvae has been identified as a possible cause of downstream displacement and poor recruitment of the endangered Rio Grande silvery minnow (Hybognathus amarus; silvery minnow). Seven experiments were conducted using artificial eggs to estimate silvery minnow egg drift and retention in the Albuquerque and Isleta reaches of the regulated Middle Rio Grande, New Mexico, USA over a range of flows during expected spawning times. Bead retention varied by reach, discharge, and shape of the hydrograph. Highest retention (6.9 and 9.7% per km in the Albuquerque and Isleta reaches, respectively) occurred on the ascending limb of a high flow in areas where there was substantial floodplain inundation. Retention was maximized at different flows in each reach (97 and 140 m³/s, respectively), possibly associated with reach‐specific floodplain inundation thresholds. Lowest retention in each reach (2.1 and 1.7%, respectively) occurred on the descending limb of low and high flows, respectively. Of the silvery minnow eggs produced in the combined Albuquerque and Isleta reaches in 2005, 8–14% are predicted to have been retained in the Albuquerque Reach (67 km) and 49–83% in the Isleta Reach (86 km) based on the distribution of adult fish and measured bead retention rates. Although silvery minnow propagules are capable of drifting long distances, our study suggests that considerable retention occurs in the Middle Rio Grande. Habitat restoration to increase channel habitat complexity, and flow management to promote floodplain inundation should help to retain a greater proportion of propagules in upstream reaches. Copyright © 2010 John Wiley & Sons, Ltd.     

Do Management Actions to Restore Rare Habitat Benefit Native Fish Conservation? Distribution of Juvenile Native Fish Among Shoreline Habitats of the Colorado River

Many management actions in aquatic ecosystems are directed at restoring or improving specific habitats to benefit fish populations. In the Grand Canyon reach of the Colorado River, experimental flow operations as part of the Glen Canyon Dam Adaptive Management Program have been designed to restore sandbars and associated backwater habitats. Backwaters can have warmer water temperatures than other habitats, and native fish, including the federally endangered humpback chub Gila cypha, are frequently observed in backwaters, leading to a common perception that this habitat is critical for juvenile native fish conservation. However, it is unknown how fish densities in backwaters compare with that in other habitats or what proportion of juvenile fish populations reside in backwaters. Here, we develop and fit multi‐species hierarchical models to estimate habitat‐specific abundances and densities of juvenile humpback chub, bluehead sucker Catostomus discobolus, flannelmouth sucker Catostomus latipinnis and speckled dace Rhinichthys osculus in a portion of the Colorado River. Densities of all four native fish were greatest in backwater habitats in 2009 and 2010. However, backwaters are rare and ephemeral habitats, so they contain only a small portion of the overall population. For example, the total abundance of juvenile humpback chub in this study was much higher in talus than in backwater habitats. Moreover, when we extrapolated relative densities based on estimates of backwater prevalence directly after a controlled flood, the majority of juvenile humpback chub were still found outside of backwaters. This suggests that the role of controlled floods in influencing native fish population trends may be limited in this section of the Colorado River. Copyright © 2014 John Wiley & Sons, Ltd.     

江苏德邦化工集团有限公司，江苏连云港 222023

1 简介 印度第一个纯碱厂始建于1932年,位于印度西部古吉拉特邦的Dhrangadhra,装置能力为50t/d。 作为基础无机化工产品,因为整个印度无天然碱矿,全部产品--包括轻灰和重灰只能以合成法生产。     

A delocalized carbanion monomer preparation: 4,5-dimethylene-1,8-octanediol for use as both functional condensation and diene monomers

Summary The 2,3-dimethylene-1,3-butadiene dianion (2), prepared from 2,3-dimethyl-1,3-butadiene (1) using Lochmann's base, has been reacted with ethylene oxide to give 4,5-dimethylene-1,8-octanediol (3). This monomer has been incorporated into a polyester via low temperature solution polymerization, and the resultant copolyester has been characterized by ¹H NMR, intrinsic viscosity, and DSC. Also, the free radically formed diene polymer of 3 has been investigated.     

The Semiconductor Research Corporation: Cooperative research

The SRC (Semiconductor Research Corporation) was formed in 1982 to conduct generic, cooperative university research in the field of integrated circuits. An overview is provided of the methodologies used by the SRC for the identification of pacing integrated-circuit technologies, for research program planning and management, and for the transfer of research results to members. Several case studies are developed that illustrate the SRC approach to the conduct of research and that give a perspective on the broad spectrum of research results being produced. The SRC has found that the process of defining generic research goals, followed by the development and implementation of research plans to achieve the stated goals, provides effective focus and metrics for measuring research progress. It is the SRC's experience that focused university research can provide substantial contributions to the advancement of semiconductor technology as well as an additional work force to enhance the industry, university, and government technical infrastructure of the United States     

PHYSIOLOGICAL CONSEQUENCES OF MINIMALLY PROCESSED FRUITS AND VEGETABLES

The physiological consequences of minimal processing are dire. Mechanical injury sets off a complex series of events which result in loss of quality (i.e. color, texture and flavor). Control of this wounding response is a major obstacle that must be overcome. To prolong postharvest life, respiration must be reduced while producing enough energy to maintain the “energized state”. The central roles of membranes and calcium in maintaining quality are discussed.     

Litigating fear: electrical and magnetic fields (EMF) and the law

A large number of persons in the United States and Europe believe that EMF causes human illness. These illnesses include childhood leukemia, other cancers, high blood pressure, the aggravation of other diseases, and electrical sensitivity syndrome. EMF has become a legal issue as people seek compensation for alleged injuries and try to have power lines relocated away from their homes. This column discusses the problem of making good legal decisions about complex scientific problems such as EMF. Topics discussed include: the history; the Denver study; fear and the law; proving negatives and the law; economic consequences of fear; and fear and the public utility consequences. The author concludes that so far, the courts and most state public-utility regulatory commissions have acted reasonably when dealing with EMF. They have recognized that the potential risk is very small, if there is any risk at all, and that the potential harm from regulation is very high. This is a precarious balance, however, and it could easily be upset by either trial judges allowing EMF cases to be litigated or a state public-utility commission giving in to public pressure and declaring EMF a threat to health. Scientists and others who understand these problems should speak out and try to shape public opinion to diminish the suffering that comes from irrational fears and the social dislocations that follow bad policy choices