65 research outputs found
Should we fear the walking dead? The role of zombie firms for productivity developments in Portugal
Productivity growth is slowing down among OECD countries. A recent strand of literature
focuses on the role of unviable firms, so-called “zombie firms”, to explain the slowdown.
Using comprehensive firm-level data, we find that by being unproductive and by obstructing
the rest of the economy through resource misallocation, zombie firms stifle firm performance
in Portugal. This is a precarious finding as the share of zombie firms in Portugal has
risen steadily from 2008 to 2013, exceeding the OECD average. Furthermore, we show that
recent structural reforms in Portugal have potentiated the exit of zombie firms by reducing
policy-induced exit barriers
Processing of thick section epoxy powder composite structures
The use of epoxy powder as the primary matrix in thick fibre-reinforced composite
parts is investigated.
The characteristics of three epoxy powders are assessed using several experimental
techniques, focusing on their curing behaviour. At least one epoxy powder is shown
to have advantageous characteristics for manufacturing thick-section composites.
Material models are developed which can describe the processing behaviour (cure
kinetics, viscosity change, etc.) of an epoxy powder. The cure kinetics model makes
use of an additional rate constant to better describe the rate of cure at both high and
low temperatures. The chemorheological model is based on an existing model for
toughened epoxies.
A one-dimensional simulation tool for manufacturing thick-section composite
laminates is developed in MATLAB. The simulation tool employs a resin flow model
for vacuum-bag-only prepregs to describe the infusion process and subsequent
thickness change. This thickness change is coupled to a model for through-thickness
heat transfer which can be solved numerically for various thermal boundary
conditions. The model is used to explore the suitability of epoxy powders for the
manufacturing thick-section composite structures.
The aforementioned simulation tool is validated against experimental results for thick-section
composite laminates. The experiments are carried out using a modified heated
tool and test apparatus which apply known thermal boundary conditions. A linear
variable differential transformer is used to measure the thickness change of each
laminate during testing, while thermocouples are used to measure the temperatures at
various positions within each laminate. The results of the tests show good agreement
with the one-dimensional simulation tool. Additional simulations are performed to
investigate the influence of material format, thickness change, and heating methods.
Methods for reducing thermal and cure gradients are explored also.
A method is outlined for implementing the process models within commercial finite
element software, Abaqus FEA. User subroutines for heat transfer and thermal
expansion are used to define the various process models. One-dimensional simulations
are validated, and a convergence study is performed on time step size and element size.
Simulations show the effect of in-plane heating for glass-fibre and carbon-fibre
laminates, and the processing of a wind turbine blade root section is investigated.
Overall, it is shown that thick-section composite structures can be manufactured using
a low-cost commodity epoxy powder from the coating industry, and that these
structures do not suffer from the risk of uncontrolable thermal events
Die Wirksamkeit von Radiowerbung für Employer Branding bei der Gewinnung von technischen Fachkräften eines regionalen mittelständischen Unternehmens
The subject of this paper is the effectiveness of radio advertising with a focus on attracting technical specialists from regional medium-sized companies. This is done on the basis of BDT Media Automation GmbH, a medium-sized B2B company from Rottweil. For this purpose, the target group is first determined and analyzed. Subsequently, five hypotheses are formed in view of the employer branding concept and an extensive literature research regarding radio advertising. These hypotheses will be examined in the empirical part of this paper by means of a study with 31 human resources managers and recruiters, and their accuracy will be tested. After evaluating the data, the results of the study are presented in order to provide BDT as well as other medium sized companies with recommendations for action regarding the effectiveness of radio as a communication tool for employee recruitment
Productivity, Zombie Firms and Exit Barriers in Portugal
Productivity growth is slowing in OECD countries, coupled with increased misallocation of resources. A recent strand of literature focuses on the role of non-viable firms "zombie firms" to explain these developments. Using a rich firm-level dataset for Portugal, we explore the role played by zombies in firm dynamics and the misallocation of labour and capital. We confirm the results on the high presence of zombie firms, which are significantly less productive than their healthy counterparts and drag down aggregate productivity. Higher zombie presence is associated with lower growth of viable firms, stifling intra-sectoral capital reallocation. Portugal has shown one of the largest reductions in barriers to exit and restructuring of all OECD countries and is therefore particularly suited for an assessment of the extensive margin effects of these policy changes. We show that a reduction in exit and restructuring barriers promotes a more effective exit channel and fosters the restructuring of the most productive zombies. The results highlight the role of public policy in addressing zombies' prevalence, fostering a more efficient resource allocation, and promoting productivity growth.publishersversionpublishe
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