A model‐data study of the 1999 St. Lawrence Island polynya in the Bering Sea

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95536/1/jgrc12221.pd

Coagulation Behavior of Aluminum Salts in Eutrophic Water: Significance of Al13Species and pH Control

The coagulation behavior of aluminum salts in a eutrophic source water was investigated from the viewpoint of Al(III) hydrolysis species transformation. Particular emphasis was paid to the coagulation effect of Al-13 species on removing particles and organic matter. The coagulation behavior of Al coagulants with different basicities was examined through jar tests and hydrolyzed Al(III) speciation distribution characterization in the coagulation process. The results showed that the coagulation efficiency of Al coagulants positively correlated with the content of Al-13 in the coagulation process rather than in the initial coagulants. Aluminum chloride (AlCl3) was more effective than polyaluminum chloride (PACT) in removing turbidity and dissolved organic matter in eutrophic water because AlCl3 could not only generate Al-13 species but also function as a pH control agent in the coagulation process. The solid-state Al-27 NMR spectra revealed that the precipitates formed from AlCl3 and PACT were significantly different and proved that the preformed Al-13 polymer was more stable than the in situ formed one during the coagulation process. Through regulating Al speciation, pH control could improve the coagulation process especially in DOC removal, and AlCl3 benefited most from pH control

Insights into high temperature pretreatment on cellulase processing of bamboo

Bamboo processing was performed with commercial cellulase. The properties of cellulase and the effect of high temperature pretreatment on cellulase hydrolysis of bamboo were investigated. Results indicated that cellulase hydrolysis performed fast and dramatically within 30 minutes, and then gradually reached its balance. It was found that pretreatment played an active role in cellulase processing, which enhanced the saccharification of bamboo and benefited high-molecular-weight lignin degradation and removal. Additionally, a better performance of bamboo processing was achieved under the cellulase concentration of 15IU in total reaction system of 100 ml at 50°C, pH 4.8, together with the high temperature pretreatment of 120°C for 15 minutes

Modeling and control of operator functional state in a unified framework of fuzzy inference petri nets

Background and objective: In human-machine (HM) hybrid control systems, human operator and machine cooperate to achieve the control objectives. To enhance the overall HM system performance, the discrete manual control task-load by the operator must be dynamically allocated in accordance with continuous-time fluctuation of psychophysiological functional status of the operator, so-called operator functional state (OFS). The behavior of the HM system is hybrid in nature due to the co-existence of discrete task-load (control) variable and continuous operator performance (system output) variable. Methods: Petri net is an effective tool for modeling discrete event systems, but for hybrid system involving discrete dynamics, generally Petri net model has to be extended. Instead of using different tools to represent continuous and discrete components of a hybrid system, this paper proposed a method of fuzzy inference Petri nets (FIPN) to represent the HM hybrid system comprising a Mamdani-type fuzzy model of OFS and a logical switching controller in a unified framework, in which the task-load level is dynamically reallocated between the operator and machine based on the model-predicted OFS. Furthermore, this paper used a multi-model approach to predict the operator performance based on three electroencephalographic (EEG) input variables (features) via the Wang-Mendel (WM) fuzzy modeling method. The membership function parameters of fuzzy OFS model for each experimental participant were optimized using artificial bee colony (ABC) evolutionary algorithm. Three performance indices, RMSE, MRE, and EPR, were computed to evaluate the overall modeling accuracy. Results: Experiment data from six participants are analyzed. The results show that the proposed method (FIPN with adaptive task allocation) yields lower breakdown rate (from 14.8% to 3.27%) and higher human performance (from 90.30% to 91.99%). Conclusion: The simulation results of the FIPN-based adaptive HM (AHM) system on six experimental participants demonstrate that the FIPN framework provides an effective way to model and regulate/optimize the OFS in HM hybrid systems composed of continuous-time OFS model and discrete-event switching controller

Enhancement of polar phases in PVDF by forming PVDF/SiC nanowire composite

Different contents of silicon carbide (SiC) nanowires were mixed with Poly(vinylidene fluoride) (PVDF) to facilitate the polar phase crystallization. It was shown that the annealing temperature and SiC content affected on the phase and crystalline structures of PVDF/SiC samples. Furthermore, the addition of SiC nanowire enhanced the transformation of non-polar α phase to polar phases and increased the relative fraction of β phase in PVDF. Due to the nucleating agent mechanism of SiC nanowires, the ion-dipole interaction between the negatively charged surface of SiC nanowires and the positive CH2 groups in PVDF facilitated the formation of polar phases in PVDF

2-(7-Meth­oxy-1-naphth­yl)acetonitrile

The mol­ecule of the title compound, C13H11NO, is almost planar (r.m.s. deviation = 0.013 Å), apart from the cyanide group, for which the C and N atoms deviate from the mean plane of the other atoms by 0.341 (3) and 0.571 (4) Å, respectively. In the crystal, weak aromatic π–π stacking [centroid–centroid distance = 3.758 (3) Å] may help to stabilize the structure

catena-Poly[[(3-methyl­sulfanyl-1,2,4-thia­diazole-5-thiol­ato)sodium]di-μ-aqua-κ4 O:O]

The crystal structure of the title compound, [Na(C3H3N2S3)(H2O)2]n, features polymeric chains made up of O⋯O edge-shared NaSN(H2O)4 units running along the b axis. The Na+ ion and all non-H atoms of the thia­diazole ligand lie on a mirror plane

Methyl 5-chloro-2-[N-(3-eth­oxy­carbonyl­prop­yl)-4-methyl­benzene­sulfonamido]­benzoate

In the title compound, C21H24ClNO6S, the benzene rings are oriented at a dihedral angles of 41.6 (2)°. In the crystal structure, weak inter­molecular C—H⋯O inter­actions link the mol­ecules