38 research outputs found
Techno-economic assessment of membrane assisted fluidized bed reactors for pure H2 production with CO2 capture
This paper addresses the techno-economic assessment of two membrane-based technologies for H2 production from natural gas, fully integrated with CO2 capture. In the first configuration, a fluidized bed membrane reactor (FBMR) is integrated in the H2 plant: the natural gas reacts with steam in the catalytic bed and H2 is simultaneously separated using Pd-based membranes, and the heat of reaction is provided to the system by feeding air as reactive sweep gas in part of the membranes and by burning part of the permeated H2 (in order to avoid CO2 emissions for heat supply). In the second system, named membrane assisted chemical looping reforming (MA-CLR), natural gas is converted in the fuel rector by reaction with steam and an oxygen carrier (chemical looping reforming), and the produced H2 permeates through the membranes. The oxygen carrier is re-oxidized in a separate air reactor with air, which also provides the heat required for the endothermic reactions in the fuel reactor. The plants are optimized by varying the operating conditions of the reactors such as temperature, pressures (both at feed and permeate side), steam-to-carbon ratio and the heat recovery configuration. The plant design is carried out using Aspen Simulation, while the novel reactor concepts have been designed and their performance have been studied with a dedicated phenomenological model in Matlab. Both configurations have been designed and compared with reference technologies for H2 production based on conventional fired tubular reforming (FTR) with and without CO2 capture. The results of the analysis show that both new concepts can achieve higher H2 yields than conventional plants (12-20% higher). The high electricity consumptions of membrane-based plants are associated with the required low pressure at the retentate side. However, the low energy cost for the CO2 separation and compression makes the overall reforming efficiency from 4% to 20% higher than conventional FTR with CO2 scrubbing. FBMR and MA-CLR show better performance than FTR with CO2 capture technology in terms of costs mainly because of lower associated CAPEX. The cost of H2 production reduces from 0.28 €/NmH23 to 0.22 €/NmH23 (FBMR) and 0.19 €/NmH23 (MA-CLR)
Voluntary disclosure of corporate strategy: determinants and outcomes. An empirical study into the risks and payoffs of communicating corporate strategy.
Business leaders increasingly face pressure from stakeholders to be transparent. There
appears however little consensus on the risks and payoffs of disclosing vital information
such as corporate strategy. To fill this gap, this study analyzes firm-specific determinants
and organisational outcomes of voluntary disclosure of corporate strategy. Stakeholder
theory and agency theory help to understand whether companies serve their interest to
engage with stakeholders and overcome information asymmetries. I connect these
theories and propose a comprehensive approach to measure voluntary disclosure of
corporate strategy. Hypotheses from the theoretical framework are empirically tested
through panel regression of data on identified determinants and outcomes and of
disclosed strategy through annual reports, corporate social responsibility reports,
corporate websites and corporate press releases by the 70 largest publicly listed
companies in the Netherlands from 2003 through 2008. I found that industry,
profitability, dual-listing status, national ranking status and listing age have significant
effects on voluntary disclosure of corporate strategy. No significant effects are found for
size, leverage and ownership concentration. On outcomes, I found that liquidity of stock
and corporate reputation are significantly influenced by voluntary disclosure of corporate
strategy. No significant effect is found for volatility of stock. My contributions to theory,
methodology and empirics offers a stepping-stone for further research into understanding
how companies can use transparency to manage stakeholder relations
Macrosocial determinants of population health in the context of globalization
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55738/1/florey_globalization_2007.pd
Mechanitis polymnia casabranca and Ithomia lichyi lichyi (Lepidoptera: Nymphalidae) damaging tree of Solanum granuloso-leprosum (Solanaceae)
The Zona da Mata region is located in southeastern Minas Gerais State, Brazil with fauna and flora diversified, including herbivorous insects and Solanaceae plants. Ithomiinae caterpillars were observed damaging tree of Solanum granuloso-leprosum Dunal (Solanaceae), used for different purposes and abundant in secondary forest. The objective of this study was to identify defoliating caterpillars of S. granuloso-leprosum at the campus of Universidade Federal de Viçosa (UFV) in Viçosa, Minas Gerais State, Brazil and review host plants of Mechanitis polymnia L., 1758 (Lepidoptera: Nymphalidae). Thirteen caterpillars found damaging a tree of S. granuloso-leprosum at the campus of UFV were collected and maintained in the Laboratório de Controle Biológico de Insetos (LCBI) from UFV until adult emergence. These caterpillars were of two species, being ten of the first and three of the second species. Adult specimens of the latter species were identified as Ithomia lichyi lichyi D'Almeida, 1939 (Lepidoptera: Nymphalidae) in the Departamento de Zoologia of Universidade Federal do Paraná (UFPR) in Curitiba, Paraná State, Brazil and of the group of ten caterpillars as Mechanitis polymnia casabranca Haensch, 1905 (Lepidoptera: Nymphalidae) in the Museu de Zoologia of Universidade de São Paulo (USP) in São Paulo State, Brazil. This is the first report of M. polymnia casabranca and I. lichyi lichyi together damaging plant of S. granuloso-leprosum in the Zona da Mata region of Minas Gerais State, Brazil and 57 plants are recorded as host of M. polymnia