ABSTRACT
The study and subsequent analysis of the interaction of calcium sulfate with added citric acid and with two additional proportions of carbon fibers of different lengths has been based on the IMR and D Method for its realization. The purpose of this work is the study of the physical and mechanical behavior of the resulting material between the intimate mixture of calcium sulfate with additives and carbon fibers, justifying said work with a link to the Sustainable Development Goals (SDG) regarding the benefits that the Calcium sulfate has contributed to civil society since times dating back to ancient Egypt. We find ourselves with a material of which the energy used in its manufacture is far from that required by steel or cement, and construction with this new compound is in a much higher stage than construction with adobe. Therefore, this is a compound that can be developed for a wide variety of applications. The novelty of this study is the inclusion of polymeric fibers in a material used over the centuries to improve its mechanical properties. With these improvements we will be able to reduce thicknesses in manufacturing, which implies a reduction in manufacturing energy and weight structures in buildings, which should be studied and analyzed in the future. The kneading of calcium sulfate with long fibers at high percentages complicates not only the results, but also the manufacturing process. As representative results of the study, we can indicate that a composite material with high mechanical capacity has been achieved, with maximum values of flexural strength of 8.12 N/mm2 and compression strength of 17.58 N/mm2.
ABSTRACT
Despite the wide literature on R-wave detection algorithms for ECG Holter recordings, the long-term monitoring applications are bringing new requirements, and it is not clear that the existing methods can be straightforwardly used in those scenarios. Our aim in this work was twofold: First, we scrutinized the scope and limitations of existing methods for Holter monitoring when moving to long-term monitoring; Second, we proposed and benchmarked a beat detection method with adequate accuracy and usefulness in long-term scenarios. A longitudinal study was made with the most widely used waveform analysis algorithms, which allowed us to tune the free parameters of the required blocks, and a transversal study analyzed how these parameters change when moving to different databases. With all the above, the extension to long-term monitoring in a database of 7-day Holter monitoring was proposed and analyzed, by using an optimized simultaneous-multilead processing. We considered both own and public databases. In this new scenario, the noise-avoid mechanisms are more important due to the amount of noise that exists in these recordings, moreover, the computational efficiency is a key parameter in order to export the algorithm to the clinical practice. The method based on a Polling function outperformed the others in terms of accuracy and computational efficiency, yielding 99.48% sensitivity, 99.54% specificity, 99.69% positive predictive value, 99.46% accuracy, and 0.85% error for MIT-BIH arrhythmia database. We conclude that the method can be used in long-term Holter monitoring systems.
