Raul Adolfo Valencia

The widespread use of lithium-ion batteries (LIBs) in energy storage systems has created a growing challenge in accurately determining their condition throughout their life through characterization such as State of Health (SOH) and State of Charge (SOC). This is critical to determine whether batteries are suitable for second-life applications or should be directed to recycling processes. Ultrasonic techniques have emerged as a non-destructive alternative to conventional electrochemical methods; however, the link between internal material properties and ultrasonic response remains insufficiently understood. This study employs numerical simulations to elucidate how mechanical variations affect Quantitative Ultrasound Spectroscopy (QUS) parameters in LIBs. The wave equation was solved using Local Radial Basis Function (L-RBF) methods and a two-dimensional model was also simulated with SimSonic to capture multi-layer interactions. The results demonstrate that increases in electrode thickness lead to decreased spectral slope and increased intercept and mid-band fit, consistent with enhanced ultrasonic attenuation and impedance mismatch. Moreover, two-dimensional analyses reveal energy gap dissipation and frequency shifts associated with evolving layer geometries. These findings confirm the feasibility of QUS-based ultrasonic metrics as reliable indicators of mechanical and electrochemical states in LIBs, offering a promising pathway for machine-learning (data-driven) SOH and SOC classification.

The present study explores novel alternatives for the exploitation of sugarcane bagasse ash by obtaining and modifying SiO₂ nanoparticles through a green synthesis method. The hydrophilic nature of the nanoparticles was modified using oleic acid. The nanoparticles were characterized using FTIR, FESEM, and DLS, and their performance in the stabilization of Pickering emulsions was also studied. FESEM micrographs of the nanoparticles revealed an irregular and agglomerated structure. EDS confirmed that their main components are oxygen and silicon, and ATR-FTIR spectra demonstrated that oleic acid effectively modified the nanoparticles. Subsequently, O/W Pickering emulsions were fabricated by combining rotor–stator homogenization and probe ultra-sonication, using dodecane and liquid paraffin as model oil phases and SiO₂ NPs as stabilizers. Static light scattering measurements showed that the emulsions exhibited polydispersity, while photographic monitoring confirmed that their physical stability was affected by the concentrations of oleic acid and nanoparticles: concentrations of up to 20.0 wt% and 1.0 wt%, respectively, produced emulsions that remained stable for 7 to 15 days. This study identifies the behavior and challenges associated with novel pathways for the valorization of sugarcane bagasse ash. The stabilization of Pickering emulsions using the obtained SiO₂ NPs highlights their potential in pharmaceutical, cosmetic, and food applications.

Photothermal therapy assisted by gold nanoparticles (GNP) has emerged as an alternative to treat cancer. GNP with rod morphologies (GNR) play the role of absorbing near-infrared radiation (NIR) provided by a heat source, causing hyperthermia in malignant cells. Localized hyperthermic effects depend on the size (aspect ratio, AR), shape and concentration of GNP, polarization of the electric field, irradiation wavelength, and properties of the medium. A computational method is presented to measure the cross and longitudinal sections of optical absorption for GNR based on optical heating of the aqueous solution of GNR with an and NIR polarized laser. In-silico study was carried out under the finite element method for Mie Theory, according to the effect of AR and cluster formation, with respect to the electric field polarization ( ). As the polarization of electric field rotates up to , the cross peak moves towards the longitudinal one. Lower concentrations result in smaller temperature gradients. This study allows the theories used to help as a basis to predict the optimal irradiation conditions against the properties of the nanomaterials used for the generation of the hyperthermia state and plasmonic coupling.

Introduction: Plasmonic photothermal therapy (PPTT) with noble metal nanoparticles (NPs) have gained great relevance as less invasive platforms in the treatment of adenocarcinoma-type cancer tumors. The PPTT uses laser radiation to generate plasmonic effects in NPs that are distributed in the cancerous tissue, producing hyperthermia and cell death by apoptosis. Objective: To obtain two-dimensional temperature distributions and the associated cell damage distributions in tumoral tissue subjected to PPTT. Method: A numerical methodology based on Radial Basis Functions (RBFs) is implemented for solving the Pennes or bioheat equation and the Arrhenius and Three-state models for cellular damage estimation. The developed, validated and applied numerical methodology is based on the method of approximate particular solutions in local formulation (LMAPS). Results: The capability to solve problems with variable sources, multiple regions and different types of boundary conditions is shown by the comparison with OpenFOAM computational tool based on finite volume method and numerical results reported in the literature. This is performed by solving hypothetical situations of heat transfer in tissues including 1D and 2D domains with metabolic sources, perfusion term and radiation thermal conversion. Conclusions: The developed methodology is applied to a situation of PPTT in superficial tissue, from laser energy distribution description to the local percentage of cellular damage. This numerical methodology is the basis of the analysis, optimization and design of PPTT application processes in clinical environments considering its potential to solve complex geometries, time-varying boundary conditions and parameters and domains with multiple regions.

Diagnosing lithium‐ion battery degradation is a crucial part of managing energy storage systems. Recent research has explored ultrasonic testing for non‐invasive health assessment as an alternative to traditional, time‐consuming, electrical‐only methods. Assessing the state of health is vital for determining quality at end of ‘first’ life, with retired batteries at 70–80 % health still holding value for secondlife applications. Over the coming years, tens of GWh of salvaged batteries will hit the market, requiring rapid noninvasive methods to classify retired batteries according to their state of health. This study uses a 64 – element ultrasonic array to obtain mid‐band quantitative ultrasound spectroscopy parameters – including mid‐band fit, spectral slope, and intercept – from circumferential waves around cylindrical batteries. Thirteen cylindrical cells were used to evaluate the methodology: three pristine and ten retired from the same source. The mid‐band fit showed the ability to track the state of charge and discriminate between the state of health levels in accelerated degradation experiments both with pristine batteries, and also with recovered secondlife batteries with unknown historical use. Linear‐array ultrasonic transducers, coupled with quantitative spectral parameters, show promise for future non‐destructive battery health screening methods, offering valuable insights for the emerging used battery market.

Background: Nowadays, the engineering vascular grafts with a diameter less than 6 mm by means of electrospinning, is an attracted alternative technique to create different three-dimensional microenvironments with appropriate physicochemical properties to promote the nutrient transport and to enable the bioactivity, dynamic growth and differentiation of cells. Although the performance of a well-designed porous wall is key for these functional requirements maintaining the mechanical function, yet predicting the flow rate and cellular transport are still not widely understood and many questions remain open about new configurations of wall can be used for modifying the conventional electrospun samples. The aim of the present study was to evaluate the effect of fabrication techniques on scaffolds composed of bovine gelatin and polycaprolactone (PCL) developed by sequential electrospinning and co-electrospinning, on the morphology and fluid-mechanical properties of the porous wall. Methodology: For this purpose, small diameter tubular structures were manufactured and experimental tests were performed to characterize the crystallinity, morphology, wettability, permeability, degradability, and mechanical properties. Some samples were cross-linked with Glutaraldehyde (GA) to improve the stability of the gelatin fiber. In addition, it was analyzed how the characteristics of the scaffold favored the levels of cell adhesion and proliferation in an in vitro model of 3T3 fibroblasts in incubation periods of 24, 48 and 72 h. Results: It was found that in terms of the morphology of tubular scaffolds, the co-electrospun samples had a better alignment with higher values of fiber diameters and apparent pore area than the sequential samples. The static permeability was more significant in the sequential scaffolds and the hydrophilic was higher in the co-electrospun samples. Therefore, the gelatin mass losses were less in the co-electrospun samples, which promote cellular functions. In terms of mechanical properties, no significant differences were observed for different types of samples. Conclusion: This research concluded that the tubular scaffolds generated by sequential and co-electrospinning with modification in the microarchitecture could be used as a vascular graft, as they have better permeability and wettability, interconnected pores, and a circumferential tensile strength similar to native vessel compared to the commercial graft analyzed.

Background: Nowadays, the engineering vascular grafts with a diameter less than 6 mm by means of electrospinning, is an attracted alternative technique to create different three-dimensional microenvironments with appropriate physicochemical properties to promote the nutrient transport and to enable the bioactivity, dynamic growth and differentiation of cells. Although the performance of a well-designed porous wall is key for these functional requirements maintaining the mechanical function, yet predicting the flow rate and cellular transport are still not widely understood and many questions remain open about new configurations of wall can be used for modifying the conventional electrospun samples. The aim of the present study was to evaluate the effect of fabrication techniques on scaffolds composed of bovine gelatin and polycaprolactone (PCL) developed by sequential electrospinning and co-electrospinning, on the morphology and fluid-mechanical properties of the porous wall. Methodology: For this purpose, small diameter tubular structures were manufactured and experimental tests were performed to characterize the crystallinity, morphology, wettability, permeability, degradability, and mechanical properties. Some samples were cross-linked with Glutaraldehyde (GA) to improve the stability of the gelatin fiber. In addition, it was analyzed how the characteristics of the scaffold favored the levels of cell adhesion and proliferation in an in vitro model of T3T fibroblasts in incubation periods of 24, 48 and 72h. Results: It was found that in terms of the morphology of tubular scaffolds, the co-electrospun samples had a better alignment with higher values of fiber diameters and apparent pore area than the sequential samples. The static permeability was more significant in the sequential scaffolds and the hydrophilic was higher in the co-electrospun samples. Therefore, the gelatin mass losses were less in the co-electrospun samples, which promote cellular functions. In terms of mechanical properties, no significant differences were observed for different types of samples. Conclusion: This research concluded that the tubular scaffolds generated by sequential and co-electrospinning with modification in the microarchitecture could be used as a vascular graft, as they have better permeability and wettability, interconnected pores, and a circumferential tensile strength similar to native vessel compared to the commercial graft analyzed.

The therapeutic approach of the atherosclerotic plaque has been visualized from multiple perspectives, which include from the handling of drugs until the implantation of medical devices like stents. A current alternative to restenosis appearance, is the use of stents with drugreleasing coatings. The present work seeks to analyze the structural and hemodynamic behavior and to understand the effects between the interaction of a stent coating manufactured in PVOH with and without the presence of carbon nanotubes with concentrations of CNT varying from 0.1 to 0.3% (Wt), through a computational study. The computational study is based on a Fluid-Structure (FSI) model in one way and with a scheme partitioned using the finite element method. In conclusion, predicting the mechanical behavior and local flow patterns of these devices may provide criteria elements that allow the improvement of the design of a stent coating

Textile vascular grafts are biomedical devices and play an important role serving as a solution for the partial replacement of damaged arterial vessels. It is believed that the success of a textile vascular graft, in the healing process after implantation, is due to the porous micro-structure of the wall. Although the transport of fluids through textiles is of great technical interest in biomedical applications, little is known about predicting the micro-flow pattern and cellular transport through the wall. The aim of this work is to investigate how the type of fabric, permeability and porosity affect both the local fluid dynamics at several scales and the fluid-particle interaction between platelets in textile grafts, related with the graft occlusion. This study involves both experimental and computational tests. Experimental tests are performed to characterize the permeability and porosity according to the ISO 7198 standard. The numerical process is based on a multi-scale approach where the fluid flow is solved with the Finite Element Method and the discrete particles are solved with the Molecular Dynamic Method. The results have shown that the type of fabric in textile vascular grafts and the degree of porosity and permeability affect both the local fluid dynamics and the level of penetration of platelets through the wall, thus indicating their importance as design parameters.