https://hdl.handle.net/10481/14173 Fri, 10 Apr 2026 21:30:59 GMT 2026-04-10T21:30:59Z https://hdl.handle.net/10481/112720 Efficient physics-based modeling and experimental validation of parallel-connected battery cells enabled by the transmission line model Rodríguez Iturriaga, Pablo; Rodríguez Bolívar, Salvador; Onori, Simona; López Villanueva, Juan Antonio Battery modules composed of parallel-connected cells are commonly used as building blocks of battery packs, but their behavior is complex due to cell dynamics, as well as cell-to-cell heterogeneities and interactions. Furthermore, their simulation by means of empirical equivalent circuit models poses limitations because of lack of generalization, whereas electrochemical models lead to a challenging calculation of the current distribution. In this article, an electrically consistent method for the calculation of the equivalent voltage and resistance of a cell is presented according to the physically motivated discrete transmission line model. This enables the efficient computation of output voltage and current distribution for parallel-connected cells while providing interpretable physical information about the operation at each level. The presented approach is validated experimentally against a dataset of a 4P module in which interconnection resistance, ambient temperature, and the presence of an aged cell are considered as input parameters, with accurate and consistent results for module voltage (≤20 mV RMS) and current distribution (≤4.4% RMS). Moreover, the proposed framework exhibits higher computational efficiency and comparable scalability in relation to established approaches, while providing improved consistency between module-level behavior and cell-level dynamics. Therefore, the proposed method based on the transmission line model and hierarchical simplification is a suitable alternative for the physically motivated simulation and analysis of battery modules. https://hdl.handle.net/10481/112720 https://hdl.handle.net/10481/111537 Hydrogel-Based Conductive Inks for the Additive Printing of Biodegradable Radiofrequency Electronic Circuits Méndez Espinosa, Álvaro; Ortiz Ruiz, Sergio; Palomo, Mikel G.; Pasadas Cantos, Francisco; Rodríguez Arco, Laura; López López, Modesto Torcuato; García Ruiz, Francisco Javier Biodegradable hydrogel-based conductive inks, with application in additive circuit manufacturing, are synthesized from agarose, sodium alginate and functional carbon-based particles (carbon nanotubes and graphite). Rheological measurements are conducted to evaluate the printing performance of each ink. The synthesized functional inks are printed, and their conductivity properties are evaluated as a function of the functional material concentration. Promising conductivity values are achieved, demonstrating their potential application for low-cost and low-environmental-impact circuital and electromagnetic designs. https://hdl.handle.net/10481/111537 https://hdl.handle.net/10481/111467 A High-Frequency Wearable IMU-Based System for Countermovement Jump Assessment Pousibet Garrido, Antonio; Benavente Bardera, Cristina; Moreno Pérez, Juan A.; Pérez Regalado, Sergio; Carvajal Rodríguez, Miguel Ángel; Chirosa Ríos, Ignacio Jesús; Escobedo Araque, Pablo The countermovement jump (CMJ) is widely used to monitor neuromuscular performance in sport, but its assessment is largely dependent on force platforms, which limits their use outside the laboratory due to their cost and limited portability. This work describes the development and validation of a fully custom wearable inertial measurement unit (IMU) system for CMJ assessment. The platform is based on a single IMU placed on the lower back and sampled at 1 kHz, and includes Bluetooth Low Energy (BLE) communication together with dedicated PC and smartphone applications. A new algorithm based on the derivative of vertical acceleration was implemented to identify take-off and landing instants. The system was evaluated using 119 CMJ trials performed by 19 participants and validated against a force platform used as the criterion reference. Different acceleration thresholds were tested, with 0.2 g providing the best compromise between detection robustness and the statistical quality of the measurements, yielding a detection rate of 97.43%. Agreement analysis showed a small systematic underestimation of flight time (bias = −0.0117 s), with moderate limits of agreement across the observed range. These results indicate that the proposed system may be suitable for practical, field-based CMJ monitoring, although the observed variability relative to force-platform measurements should be considered, particularly in applications requiring individual-level decision making. https://hdl.handle.net/10481/111467 https://hdl.handle.net/10481/111411 Experimental evaluation of the dynamic route map in the reset transition of memristive ReRAMs Maldonado, David In this paper, we analyze the reset transition in bipolar TiN/Ti/HfO 2 (10 nm)/Al 2 O 3 (2 nm)/W ReRAM de- vices using a tool that allows studying the temporal behaviour of these devices. This tool, the Dynamic Route Map (DRM), provides information about the temporal evolution of the state variable that governs the behaviour of the device, thus allowing an increased insight into resistive switching processes. Here, we show that this DRM is a powerful tool, that may help explaining some non intuitive behaviours of memristors, like the difference in the reset voltage when the inputs are from different frequency or shape. Using this tool, this fact can be explained as a different trajectory on a unique surface defining the device. As a first step, we have used two different models, one based on a physical description, and another one based on the mathematical definition of memristor as a non linear relation between charge and flux. We check that similar DRM can be obtained from both models. Additionally, several series of set-reset tran- sitions have been measured using voltage ramps of different slopes. From the measured transitions, the corresponding resistance has been extracted and, assuming conductive filaments (CF) as the switching mechanism, the corresponding CF radius has been calculated. Using these data, we show that explana- tions from the model are also supported when using experimental data, thus proving the validity of the approach. https://hdl.handle.net/10481/111411 https://hdl.handle.net/10481/110965 Microdroplet based disposable sensor patch for detection of α-amylase in human blood serum Bhattacharjee, Mitradip; Middya, Sagnik; Escobedo Araque, Pablo; Chaudhuri, Joydip; Bandyopadhyay, Dipankar; Dahiya, Ravinder Concentration of α-amylase in human serum is a key indicator of various pancreatic ailments and an affordable point-of-care detection of this biomarker can benefit millions suffering from these diseases. In view of this situation, we report the development of a flexible patch-sensor, which simply requires a microdroplet of aqueous starch-FeSO4 solution to detect α-amylase in serum. The detection is achieved through the generation of mixing vortices (~12 rpm) inside the droplet with the help of an imposed thermal gradient. Such vortices due to Marangoni and natural convections are found to be strongest at an optimal temperature difference of ~18 °C – 23 °C across the droplet which in turn facilitate mixing and promote the specific starch-amylase enzymatic reaction. Subsequently, the large (~80%) variation in the electrical resistance across the droplet is correlated to detect the level of the α-amylase in the analyte. Importantly, the sensor can detect even in the limits of 15–110 units/liter. Further, the sensitivity of flexible sensors is ~8.6% higher than the non-flexible one. Interestingly, the sensitivity of the proposed sensor has been nearly three-times than the previously reported optical ones. The results of patch-sensor match very closely with the standard path-lab tests while detecting unknown level of amylase in serum. The prototype has shown significant potential to translate into an affordable device for the real-time detection and easy prognosis of pancreatic disorders. https://hdl.handle.net/10481/110965