An Evaluation of the Applicability of Nonlinear Programming Algorithms to a Typical Commercial Process Flowsheeting Simulator. (Volumes I and II).

An efficient methodology for using commercial flowsheeting programs with advanced mathematical programming algorithms has been developed for the optimization of operating plants. The methodology was demonstrated and validated using ChemShare Corporation\u27s DESIGN/2000 simulation of the Freeport Chemical Company\u27s plant for sulfuric acid manufacture and three nonlinear programming techniques; successive linear programming, successive quadratic programming and the generalized reduced gradient method. The application of this methodology begins with the development of a feasible base case simulation. Partial derivatives of the economic model and constraint equations are computed using fully converged simulations. This information is used to formulate an optimization problem which can be solved with the NLP algorithms giving improved values of the economic model. A line search is constructed through the point found from the nonlinear programming algorithm to find the best feasible point to repeat the procedure. The procedure is repeated using the ChemShare simulation program and the NLP code until convergence criteria are met. The algorithms were applied on an iterative basis such that the engineer maintained an active role throughout the course of the optimization. This method was applied to three flowsheeting problems; a plant scale contact sulfuric acid process model, a packed bed reactor design model, and an adiabatic flash problem. The results of the optimization studies indicate that the three algorithms investigated, SLP, SQP and GRG, located the optimum of the economic model and satisfied the constraints at similar levels of efficiency. This efficiency is equivalent to those observed by other workers using similar simulation models. One important conclusion from this work is that the method of application, which includes the selection of feasible versus infeasible path, line search parameters, and the means for obtaining derivative data, is more significant than the nature of the optimization algorithm. Future research into flowsheeting and optimization should attempt to determine, establish and standardize efficient and reliable methods for the evaluation of the function and derivative information necessary for optimization. The importance of scaling to the efficiency and success of SQP methods indicates that future research in this area should seek to establish procedures for determining optimal scaling sets

Market Structure, Organizational Structure, and R&D Diversity

We examine the effects of market structure and the internal organization of firms on equilibrium R&D projects. We compare a monopolist's choice of R&D portfolio to that of a welfare maximizer. We next show that Sah and Stiglitz's finding that the market portfolio of R&D is independent of the number of firms under Bertrand competition extends to neither Cournot oligopoly nor a cartel. We also show that the ability of firms to pre-empt R&D by rivals along particular research paths can lead to socially excessive R&D diversification. Lastly, using Sah and Stiglitz's definition of hierarchy, we establish conditions under which larger hierarchies invest in smaller portfolios.

Barriers to recovery and recommendations for change: the Pennsylvania Consensus Conference on psychiatry\u27s role.

OBJECTIVE: Recovery has emerged over the past decade as a dominant theme in public mental health care. METHODS: The 2006 Pennsylvania Consensus Conference brought together 24 community psychiatrists to explore the barriers they experienced in promoting recovery and their recommendations for change. RESULTS: Twelve barriers were identified and classified into one of three categories: psychiatry knowledge, roles, and training; the need to transform public mental health systems and services; and environmental barriers to opportunity. Participants made 22 recommendations to address these barriers through changes in policies, programs, and psychiatric knowledge and practice. CONCLUSIONS: The recommendations identify areas for change that can be accomplished through individual psychiatrist action and organized group efforts

Regulatory activity revealed by dynamic correlations in gene expression noise

Gene regulatory interactions are context dependent, active in some cellular states but not in others. Stochastic fluctuations, or 'noise', in gene expression propagate through active, but not inactive, regulatory links^(1,2). Thus, correlations in gene expression noise could provide a noninvasive means to probe the activity states of regulatory links. However, global, 'extrinsic', noise sources generate correlations even without direct regulatory links. Here we show that single-cell time-lapse microscopy, by revealing time lags due to regulation, can discriminate between active regulatory connections and extrinsic noise. We demonstrate this principle mathematically, using stochastic modeling, and experimentally, using simple synthetic gene circuits. We then use this approach to analyze dynamic noise correlations in the galactose metabolism genes of Escherichia coli. We find that the CRP-GalS-GalE feed-forward loop is inactive in standard conditions but can become active in a GalR mutant. These results show how noise can help analyze the context dependence of regulatory interactions in endogenous gene circuits

Demonstration of an agroforestry system to minimize pollution hazards from land application of treated municipal sludge

Iowa has over 700 communities that generate municipal biosolids by various treatment means. These biosolids contain valuable nutrients. In this study, municipal biosolids are applied to trees, perennial grasses, and corn/soybean crops in an alley cropping (repeated tree strips combined with crops) system. The goal is to produce economical quantities of biomass and grains with reduced use of fossil fuel-based fertilizers and minimal environmental impacts

Upper Elementary School Teachers’ Perceptions of Using Audiobooks for Reluctant Readers

The problem that prompted this study was that educators’ perceptions were unknown regarding the use of audiobooks in classroom settings to help reluctant readers develop independent reading habits at a suburban elementary school in Southeast Michigan. This lack of awareness represents a gap in practice that reflects a potential need for increased understanding about how the use of audiobooks in classroom settings may help reluctant readers develop independent reading habits. The purpose of this basic qualitative project study was to examine third through fifth grade educators’ perceptions on the use of audiobooks in classroom settings to help reluctant readers develop independent reading habits who attend a suburban elementary school in Southeast Michigan. The conceptual framework for this study was Vygotsky’s social constructivist theory. Research questions explored the perceptions of educators in third through fifth grades, including how barriers and/or facilitators were perceived regarding the use of audio books to help reluctant readers develop independent reading habits. Purposeful sampling was used to select 13 educators serving students in third through fifth grades in separate one-on-one interviews. Thematic analysis and coding identified four major themes: access, engagement, reading while listening, and barriers. The participants expressed a need for professional development around the use of audiobooks which led to the development of a 3-day professional development project. The findings of this study may lead to positive social change as audiobooks could enhance students’ independent reading habits, resulting in increased literacy, higher education opportunities, and higher paying job prospects, which could positively impact socioeconomic status and lower poverty levels

Upper Elementary School Teachers’ Perceptions of Using Audiobooks for Reluctant Readers

The problem that prompted this study was that educators’ perceptions were unknown regarding the use of audiobooks in classroom settings to help reluctant readers develop independent reading habits at a suburban elementary school in Southeast Michigan. This lack of awareness represents a gap in practice that reflects a potential need for increased understanding about how the use of audiobooks in classroom settings may help reluctant readers develop independent reading habits. The purpose of this basic qualitative project study was to examine third through fifth grade educators’ perceptions on the use of audiobooks in classroom settings to help reluctant readers develop independent reading habits who attend a suburban elementary school in Southeast Michigan. The conceptual framework for this study was Vygotsky’s social constructivist theory. Research questions explored the perceptions of educators in third through fifth grades, including how barriers and/or facilitators were perceived regarding the use of audio books to help reluctant readers develop independent reading habits. Purposeful sampling was used to select 13 educators serving students in third through fifth grades in separate one-on-one interviews. Thematic analysis and coding identified four major themes: access, engagement, reading while listening, and barriers. The participants expressed a need for professional development around the use of audiobooks which led to the development of a 3-day professional development project. The findings of this study may lead to positive social change as audiobooks could enhance students’ independent reading habits, resulting in increased literacy, higher education opportunities, and higher paying job prospects, which could positively impact socioeconomic status and lower poverty levels