Feedback linearization control design for systems with fuzzyuncertainty

We derive a state feedback control design for nonlinear systems with fuzzy uncertainty. We use a fuzzy version of the Kolmogorov forward equation and an equivalent deterministic system to represent the effects of the fuzzy uncertainty. Feedback linearization of the equivalent deterministic system cancels both the system nonlinearities and the effects of the fuzzy uncertainty on the state membership function. Our controller obtains asymptotic stability and an approximation to our controller drives the system state to a small bounded set     

Practices in the recruitment and hiring of faculty for psychology departments in Canadian universities.

Investigated faculty recruitment and hiring practices of psychology departments in Canadian universities, as well as the job search experiences of recently hired male and female faculty. Questionnaires were sent to 61 departments and 105 faculty, and data from 38 completed department questionnaires and 64 faculty questionnaires were analyzed. Results indicate that the majority of psychology departments lacked complete affirmative action policies, and many lacked other specific requirements for ensuring participation by women. In spite of some deterrents to full equality, including a salary differential favoring men, it appears that women are being hired in proportion to their representation in the psychology labor force. Differences in male and female applicants that may favor the hiring of male faculty were found to be few. (French abstract) (24 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Degradation of Methyl β-D-Ribopyranoside and Methyl β-D-Xylopyranoside by Oxygen in Aqueous Sodium Hydroxide Solution

Methyl β-D-ribopyranoside (1) and methyl β-D-xylopyranoside (2) were degraded by oxygen (0.682 MPa partial pressure) in 1.25 M sodium hydroxide at 120°C. The degradations of 1 and 2 were similar to the previously reported degradations of 1,5-anhydroribitol (3) and 1,5-anhydroxylitol (4), respectively.⁴ Both hydrogen peroxide and stable organic peroxides were detected in the reactions of 1 and 2. The riboside 1 degraded faster than the xyloside 2. This difference in reactivity is proposed to be a function of the relative acidity of the glycosides. Ionization of hydroxyl groups is postulated to be favored in 1, thus facilitating the initiation of the free radical degradation. The degradations of both 1 and 2 exhibited complex kinetics indicating autoinhibited reactions. In spite of the differences in reactivity, glycosidic bond cleavage occurred in approximately 60% of the degradations for both 1 and 2. C-1 radicals, resulting from abstraction of the anomeric hydrogen atom, are proposed to cause the observed autoinhibition via termination reactions with α-hydroxyhydroperoxyl radicals. However, decomposition of the glycosides via C-1 radicals is not believed to constitute a major degradation pathway since the reactivities of 1 and 2 were essentially the same as the analogous 1,5-anhydroalditols, i.e. 3 and 4, respectively. The major acidic degradation products of 1 and 2 were identical, but were formed in different relative ratios. The major acidic products were methoxyacetic acid, lactic acid, glycolic acid, glyceric acid, a methyl 3-C-carboxyfuranoside, and two isomeric 2-C-carboxyfuranosides.     

Modification of Loblolly Pine Chips with Ceriporiopsis subvermispora Part 1: Effect of Fungal Treatment

Abstract

The effect of treating loblolly pine (Pinus taeda) chips with the fungus Ceriporiopsis subvermispora was investigated by assessing the wood changes at 2 and 4 weeks incubation relative to a control (no fungal treatment). Scanning electron microscopy indicated that during the first 2 weeks of colonization, C. subvermispora had grown over the surface of the chips and also within ray cells. A mass loss of 5% occurred after 2 weeks, 6% after four weeks. The extractives were reduced 23% in the first 2 weeks of fungal treatment and 32% after 4 weeks. Lignin loss was statistically insignificant at 2 weeks but reached 8% of the original lignin after 4 weeks. The carbohydrate content of the treated wood showed no significant differences from the control after 2 weeks and only minor losses after 4 weeks. The fraction of the wood soluble in 1% NaOH was 14.9% at 2 weeks compared to 11.5% for the control chips and increased to 18.8% after 4 weeks. This indicated only a mild decay due to the fungal treatment. At 2 weeks of fungal treatment, the lignin phenolic hydroxyl content was not significantly different from the control. However, after 4 weeks of treatment the phenolic hydroxyl groups increased by 14%. Small increases in the average pore size of the wood occurred with incubation time, including a broadening in the range of pore sizes.     

Modification of Loblolly Pine Chips with Ceriporiopsis subvermispora Part 2: Kraft Pulping of Treated Chips

Abstract

Loblolly pine (Pinus taeda) chips treated with Ceriporiopsis subvermispora for two or four weeks were pulped with different combinations of kraft pulping conditions to obtain a better understanding of the interaction between the fungal action and the pulping variables. Two different levels of effective alkali (18 or 22%), two times at maximum T_max (60 or 90 min), 22% sulfidity, and a T_max of 170°C, were used. The best delignification without adversely affecting pulp viscosity was found in pulps made from chips treated with the fungus for 2 weeks and at the mildest pulping conditions. At all pulping conditions there was a substantial decrease in the amount of rejects with 2 weeks of fungal treatment. Pulps from fungally‐treated chips refined more easily than the control pulp and strength properties of pulps of fungally‐treated chips were superior to those of the control pulp.     

An improved log-likelihood gradient for continuous-time stochasticsystems with deterministic input

Using a covariance operator approach, we derive an explicit expression for the log-likelihood ratio gradient for system parameter estimation for continuous-time stochastic systems with deterministic inputs. The gradient formula includes the smoother estimates and derivatives of system matrices with no derivatives of estimates or covariance matrices. A deterministic input is also permitted, and the state noise covariance is not required to be nonsingular. Stable numerical techniques to calculate the gradient are also discussed     

A review of pervaporation for product recovery from biomass fermentation processes

The original article to which this Erratum refers was published in Journal of Chemical Technology and Biotechnology 80 :603–629.