119 research outputs found
THE INFLUENCE OF WAVE PATTERNS AND FREQUENCY ON THERMO-ACOUSTIC COOLING EFFECT
With the increasing environmental challenges, the search for an environmentally benign cooling technology that has simple and robust architecture continues. Thermo-acoustic refrigeration seems to be a promising candidate to fulfil these requirements. In this study, a simple thermo-acoustic refrigeration system was fabricated and tested. The thermo-acoustic refrigerator consists of acoustic driver (loudspeaker), resonator, stack, vacuum system and testing system. The effect of wave patterns and frequency on thermo-acoustic cooling effect was studied. It was found that a square wave pattern would yield superior cooling effects compared to other wave patterns tested
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
Development and Assessment of Thermoacoustic Generators Operating by Waste Heat from Cooking Stove
The Development of Swirling Decaying Laminar Flow in an Annular Pipe
Work on the hydrodynamic entry length of pipe and duct flow has been well studied over the years. The assumption of fully developed flows is commonly used in many practical engineering applications (e.g. Moody's chart). For laminar axial pipe flow, the hydrodynamic entry length can be found through the monomial proposed by Kays, Shah and Bhatti (KSB) (Lh=0.056ReDh). In contrast, several approximations exist for fully turbulent flows (i.e. 10Dh-150Dh). Through theoretical and numerical investigations, the hydrodynamic entry length for swirling decaying pipe flow in the laminar regime is investigated. It was found that, the development length Lh for the axial velocity profile changes when a tangential component is added to the mean flow. The reduction in the hydrodynamic length was found to be dependent on the inlet swirl angle θ. The results indicate that a modification can be made on the KSB equation for two-dimensional swirling annular pipe flow
The Development of Swirling Decaying Laminar Flow in an Annular Pipe
Work on the hydrodynamic entry length of pipe and duct flow has been well studied over the years. The assumption of fully developed flows is commonly used in many practical engineering applications (e.g. Moody's chart). For laminar axial pipe flow, the hydrodynamic entry length can be found through the monomial proposed by Kays, Shah and Bhatti (KSB) (Lh=0.056ReDh). In contrast, several approximations exist for fully turbulent flows (i.e. 10Dh-150Dh). Through theoretical and numerical investigations, the hydrodynamic entry length for swirling decaying pipe flow in the laminar regime is investigated. It was found that, the development length Lh for the axial velocity profile changes when a tangential component is added to the mean flow. The reduction in the hydrodynamic length was found to be dependent on the inlet swirl angle θ. The results indicate that a modification can be made on the KSB equation for two-dimensional swirling annular pipe flow
- …