Wearable impedance plethysmography and electrocardiography sensor

Wearable technology has become increasingly popular in the last few years. This project describes the design and implementation of a wearable impedance plethysmography and electrocardiography sensor. This sensor is developed to be compact and lightweight while having a very extended battery life. This way, it can be easily integrated into other wearable devices or into clothing or shoes. The acquired IPG and ECG data will be transmitted in real-time to a receiving host for further storage and processing by using the Bluetooth Low Energy protocol. By using a so widespread low energy wireless protocol, the data can be received into any compatible device, such as smartphones, laptops or even specialized systems. An android application showing a real-time graphic of the measured signals is also developed for demonstration purposes. To meet the low power consumption requirements of the analog front-end circuitry, multiple techniques were used, such as using low power versions of components such as operational amplifiers and even taking advantage of their limitations to improve circuit performance characteristics. Other techniques such as sensing the correct placement of electrodes or disabling parts of the circuitry when not needed or the signal is not available were also used. A current consumption for the analog frontend in the order of only 100 µA to 200 µA at 3V was achieved while continuously providing both IPG and ECG data. For the digital circuitry, consisting mainly of the nRF51822 System on Chip from Nordic Semiconductor and some peripherals, multiple techniques of power consumption minimization were also used. A current consumption of around 200 µA to 300 µA was achieved, again at 3V, during continuous data processing and transmission. A prototype was implemented on a PCB. Unfortunately, full functionality was not achieved mainly due to some hardware failures and time constraints, however, as multiple innovative solutions were implemented, this work will provide useful information to improve other research projects in this area.Objectius de Desenvolupament Sostenible::3 - Salut i Benesta

Constitutive and numerical modeling of chemical and mechanical phenomena in solid oxide fuel cells and oxygen permeable membranes

A relation between diffusion of the oxygen ions, chemical expansion in electrochemical ceramics, and chemically induced stress evolution in the cathode over time for the Single Chamber Solid Oxide Fuel Cell based on the miniaturisation concept using thick films produced by screen-printing method has been established. The proposed model has been used to calculate the time dependent stress distribution in the cathode as a function of the material parameters, geometrical parameters of the cathode, and concentration of the oxygen ions under steady state operating conditions of the Single Chamber Solid Oxide Fuel Cell.Виконано моделювання хімічних і механічних явищ, та розроблені узагальнені визначальні співвідношення, які можуть бути використано для розрахунків залежних від часу розподілень напружень та пошкоджуваності, що обумовлена повзучістю, в твердооксидних паливних елементах та в мембранах для переносу кисню як функцій матеріалу та параметрів паливного елементучи мембрани, які знаходяться в несталих та сталих умовах роботи. Розроблені визначальні співвідношення впроваджено в формі структурних моделей для аналізу розподілу напружень в паливних елементах і в мембранах та деградації в часі, для аналізу міцності та тривалої міцності, для забезпечення безпечної роботи систем паливних елементів та мембран для стаціонарного та транспортного використанн

Modelling of Elastic Deformation for Initially Anisotropic Materials Sustaining Unilateral Damage

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Long term evolution of bone reconstruction with bone graft substitutes

The review involves clinical and experimental data, constitutive modeling, and computational investigations towards an understanding on how mechanical cyclic loads for long periods of time affect damage evolution in a reconstructed bone, as well as, lifetime reduction of bone graft substitutes after advanced core decompression. The outcome of the integrated model discussed in this paper will be how damage growth in femur after advanced core decompression subjected to mechanical cyclic loading under creep and fatigue conditions may be controlled in order to optimize design and processing of bone graft substitutes, and extend lifetime of bone substitutes

LONG TERM EVOLUTION OF BONE RECONSTRUCTION WITH BONE GRAFT SUBSTITUTES

The review involves clinical and experimental data, constitutive modeling, and computational investigations towards an understanding on how mechanical cyclic loads for long periods of time affect damage evolution in a reconstructed bone, as well as, lifetime reduction of bone graft substitutes after advanced core decompression. The outcome of the integrated model discussed in this paper will be how damage growth in femur after advanced core decompression subjected to mechanical cyclic loading under creep and fatigue conditions may be controlled in order to optimize design and processing of bone graft substitutes, and extend lifetime of bone substitutes