Search

Immediate release, compositionally proportional formulations of acyclovir comprising porous tribasic calcium phosphate were developed and compared with commercial tablets. Comparison of the dissolution behavior was carried out using a compendial method, as well as with the help of a biorelevant dissolution stress test device, which simulates physiological mechanical stress occurring in the gastrointestinal tract. The results showed that the way how tribasic calcium phosphate is used (intra- or extragranular) had an impact on the mechanical properties of tablets as well as their dissolution performance. The dissolution rate of acyclovir from the developed formulations was fast and similar to marketed formulations.

Product lines are widely used to manage families of products that share a common base of features. Typically, not every combination (configuration) of features is valid. Feature models are a de facto standard to specify valid configurations and allow standardized analyses on the variability of the underlying system. A large variety of such analyses depends on computing the number of valid configurations. To analyze feature models, they are typically translated to propositional logic. This allows to employ # SAT solvers that compute the number of satisfying assignments of the propositional formula translated from a feature model. However, the # SAT problem is generally assumed to be even harder than SAT and its scalability when applied to feature models has only been explored sparsely. Our main contribution is an investigation of the performance of off-the-shelf # SAT solvers on computing the number of valid configurations for industrial feature models. We empirically evaluate 21 publicly available # SAT solvers on 130 feature models from 15 subject systems. Our results indicate that current solvers master a majority of the evaluated systems (13/15) with the fastest solvers requiring less than one second for each successfully evaluated feature model. However, there are two complex systems for which none of the evaluated solvers scales. For the given experiment design, the solvers that consumed the least runtime are sharpSAT (2.5 seconds in sum for the 13 systems) and Ganak (3.5 seconds).

Second‐order and first‐order magnetocaloric materials (MCMs) not experiencing hysteresis are characterized by a reversible temperature change when exposed to an applied magnetic field. Due to this property described by the magnetocaloric effect, MCMs are used in magnetic cooling applications. Conversely, a rapid variation of the MCM's temperature around its specific Curie temperature causes a fast change in its magnetic permeability. Cycling the MCM's temperature within a magnetic field allows the possibility of inducing voltage, which would be higher for rapid cycling rates. Herein, latent heat transfer is introduced as an approach to obtain higher heating/cooling cycle frequency in a magnetocaloric generator that converts heat to electricity. In practice, rapid condensation/evaporation cycles of the water on a first‐order magnetocaloric La(Fe,Si) alloy are observed in a high vacuum system. This leads to the fast change of magnetization in an applied magnetic field from which an induced voltage is picked up. With the constructed set‐up, a peak induced voltage 2.75 mVpis obtained from low‐grade heat having reservoir temperature differences of △T= 56 °C. At higher temperature differences, a peak‐to‐peak voltage of around 3.5 mVppat a cycle frequency of 2 Hz is achieved. The thermomagnetic generator, herein, makes use of latent heat transfer from the working fluid to heat up and cool down a magnetocaloric material (MCM) around its Curie temperature. High temperature cycling frequencies that result in the more rapid change of magnetization lead to an induced peak‐to‐peak voltage of 3.5 mVppat a cycle frequency of 2 Hz.

It is expected that combined heat and power (CHP) micro-units will soon play a significant role in the energy supply of private households. To increase the reliability of the system the isolated operation of this micro-grid should be possible. It is assumed that the electrical load is the reference input variable of the local grid to reduce the necessity of electrical energy storages. The produced thermal energy will be stored. The paper presents a study of the voltage and frequency stability in micro-grids powered by CHP micro-units. The simulation model of the micro-co-generation plant is based on a combustion engine and brush-less synchronous generator. The example network represents an urban residential neighbourhood. The electrical household loads are based on probabilistic modelling, with high time resolution. Several scenarios for normal and disturbed operation are defined, which vary in electrical load, number and size of the CHP units and the generation schedule. For these scenarios the stability and voltage limits during normal operation and for selected three phase faults are investigated. The voltage and frequency stability of the micro-grid is determined by dynamic simulations.

Diclofenac sodium was used as a model drug for preparation of delayed-release (DR) multiparticulates, which were further processed into solid oral dosage forms such as capsules and tablets. Multiple unit pellets systems (MUPS) were prepared from different types of starter pellets (inert cores) including microcrystalline cellulose pellets, sugar spheres, isomalt pellets and novel calcium phosphate-based pellets. The study results showed that the material of the inert cores affected both mechanical properties of the drug-loaded pellets and the dissolution characteristic of the model drug. Biorelevant dissolution method carried out with the help of a pHysio-grad device allowed thorough examination of the developed formulations in the environment mimicking pH conditions along gastrointestinal tract. This method revealed significant differences between the formulations and their sensitivity to variable hydrodynamic conditions.