The closed vowels in West Frisian revisited:On the mismatch between phonetic duration and phonological length

In most of the literature on West Frisian, it is assumed that this language has a symmetrical vowel system, consisting of nine short and nine corresponding long vowels. These vowels all occur in minimal pairs, meaning that this distinction has phonemic value. This traditional view was challenged in De Haan (1999), where an asymmetrical classification is proposed in which the closed vowels /i/, /y/ and /u/, in spite of their short duration, are considered to be long vowels. In this paper, I want to assess the pros and cons of this asymmetrical classification, add some new arguments in favour of it, and come up with a representation of /i/, /y/ and /u/ which captures both their phonological length and phonetic duration.In most of the literature on West Frisian, it is assumed that this language has asymmetrical vowel system, consisting of nine short and nine corresponding longvowels. These vowels all occur in minimal pairs, meaning that this distinction has phonemic value. This traditional view was challenged in De Haan (1999), where an asymmetrical classification is proposed in which the closed vowels /i/, /y/ and /u/, in spite of their short duration, are considered to be long vowels. In this paper, I want to assess the pros and cons of this asymmetrical classification, add some new arguments in favour of it, and come up with a representation of /i/, /y/ and /u/ which captures both their phonological length and phonetic duratio

Model Checker for Java Programs

Java Pathfinder (JPF) is a verification and testing environment for Java that integrates model checking, program analysis, and testing. JPF consists of a custom-made Java Virtual Machine (JVM) that interprets bytecode, combined with a search interface to allow the complete behavior of a Java program to be analyzed, including interleavings of concurrent programs. JPF is implemented in Java, and its architecture is highly modular to support rapid prototyping of new features. JPF is an explicit-state model checker, because it enumerates all visited states and, therefore, suffers from the state-explosion problem inherent in analyzing large programs. It is suited to analyzing programs less than 10kLOC, but has been successfully applied to finding errors in concurrent programs up to 100kLOC. When an error is found, a trace from the initial state to the error is produced to guide the debugging. JPF works at the bytecode level, meaning that all of Java can be model-checked. By default, the software checks for all runtime errors (uncaught exceptions), assertions violations (supports Java s assert), and deadlocks. JPF uses garbage collection and symmetry reductions of the heap during model checking to reduce state-explosion, as well as dynamic partial order reductions to lower the number of interleavings analyzed. JPF is capable of symbolic execution of Java programs, including symbolic execution of complex data such as linked lists and trees. JPF is extensible as it allows for the creation of listeners that can subscribe to events during searches. The creation of dedicated code to be executed in place of regular classes is supported and allows users to easily handle native calls and to improve the efficiency of the analysis

Microdroplet impact at very high velocity

Water microdroplet impact at velocities up to 100 m/s for droplet diameters from 12 to 100 um is studied. This parameter range covers the transition from capillary-limited to viscosity-limited spreading of the impacting droplet. Splashing is absent for all measurements; the droplets always gently spread over the surface. The maximum spreading radius is compared to several existing models. The model by Pasandideh-Fard et al. agrees well with the measured data, indicating the importance of a thin boundary layer just above the surface, in which most of the viscous dissipation in the spreading droplet takes place. As explained by the initial air layer under the impacting droplet, a contact angle of 180 degrees is used as model input

On the spreading of impacting drops

The energy budget and dissipation mechanisms during droplet impact on solid surfaces are studied numerically and theoretically. We find that for high impact velocities and negligible surface friction at the solid surface (i.e. free-slip), about one half of the initial kinetic energy is transformed into surface energy, independent of the impact parameters and the detailed energy loss mechanism(s). We argue that this seemingly universal rule is related to the deformation mode of the droplet and is reminiscent of pipe flow undergoing a sudden expansion, for which the head loss can be calculated by multiplying the kinetic energy of the incoming flow by a geometrical factor. For impacts on a no-slip surface also dissipation in the shear boundary layer at the solid surface is important. In this case the geometric head loss acts as a lower bound on the total dissipation (i.e. the spreading on a no-slip surface approaches that on a free-slip surface when the droplet viscosity is send to zero). This new view on the impact problem allows for simple analytical estimates of the maximum spreading diameter of impacting drops as a function of the impact parameters and the properties of the solid surface. It bridges the gap between previous momentum balance approaches and energy balance approaches, which hitherto did not give consistent predictions in the low viscosity limit. Good agreement is found between our models and experiments, both for impacts on "slippery" or lubricated surfaces (e.g. Leidenfrost droplet impacts and head-on droplet-droplet collisions) and for impacts on no-slip surfaces

Synthesis of 18F-labelled 2-fluoro-1,4-quinones using acetylhypofluorite

The fluorination of 1,4-benzo- and naphthoquinones using [18F]acetylhypofluorite is described. For compounds with electron-donating substituents fair to good radiochemical yields have been reached