Ramos-González, J. (Juan Carlos)
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- Monitoring and thermal performance evaluation of two building envelope solutions in an apartment building(EDP Sciences, 2020) Arregi, B. (Beñat); Ramos-González, J. (Juan Carlos); Astudillo, J. (Julen); Garay-Martinez, R. (Roberto)A bio-based multi-layer building envelope assembly has been developed for its integration in newly built and retrofitted buildings. Forest-based materials and biocomposite profiles are used as an alternative to fossil-based insulants and metallic framing, providing a well-insulated and low-thermal-bridge technical solution. The wall assembly has been installed as the external envelope of one apartment of a housing block in Donostia-San Sebastián (Basque Country, Spain). A comparative study has been performed for the bio-based wall and the reference wall of the building. Their in-situ thermal resistance has been obtained by means of three different methods: (1) the steady-state average method, (2) a semi-dynamic method from heat balance at the internal surface, and (3) a dynamic multiple regression method. Reasonably consistent results have been obtained with the three methods: a discussion is provided on the influence of measuring periods and boundary conditions. Outputs from this experimental campaign are valuable as a counterpoint to desktop studies and tests under controlled laboratory conditions. Learnings and outputs from the present study should contribute to a better understanding of the in-situ performance of building envelope assemblies and their assessment methods.
- In Vitro Model for Simulating Drug Delivery during Balloon-Occluded Transarterial Chemoembolization.(MDPI, 2021) Aramburu-Montenegro, J. (Jorge); Antón-Remírez, R. (Raúl); Fukamizu, J. (Junichi); Nozawa, D. (Daiki); Ramos-González, J. (Juan Carlos); Sangro, B. (Bruno); Bilbao-Jaureguízar, J. (José Ignacio); Tomita, K. (Kosuke); Matsumoto, T. (Tomohiro); Hasebe, T. (Teremitsu)Simple Summary Liver cancer is one of the leading causes of cancer-related deaths worldwide and balloon-occluded transarterial chemoembolization (B-TACE) has emerged as a safe and effective treatment for liver cancer. However, the hemodynamic alterations that are responsible for the successfulness of the treatment and are produced by the microballoon catheter used during the treatment are not yet well understood. In this study, we developed an in vitro model (IVM) that can simulate B-TACE. We designed clinically relevant experiments, and we obtained clinically realistic results. We conclude that the IVM allows for a visual understanding of a complex phenomenon (i.e., the blood flow redistribution after balloon occlusion) and it could be used as a base for future sophisticated and even patient-specific IVMs; in addition, it could be used to conduct IVM-based research on B-TACE. Background: Balloon-occluded transarterial chemoembolization (B-TACE) has emerged as a safe and effective procedure for patients with liver cancer, which is one of the deadliest types of cancer worldwide. B-TACE consist of the transcatheter intraarterial infusion of chemotherapeutic agents, followed by embolizing particles, and it is performed with a microballoon catheter that temporarily occludes a hepatic artery. B-TACE relies on the blood flow redistribution promoted by the balloon-occlusion. However, flow redistribution phenomenon is not yet well understood. Methods: This study aims to present a simple in vitro model (IVM) where B-TACE can be simulated. Results: By visually analyzing the results of various clinically-realistic experiments, the IVM allows for the understanding of balloon-occlusion-related hemodynamic changes and the importance of the occlusion site. Conclusion: The IVM can be used as an educational tool to help clinicians better understand B-TACE treatments. This IVM could also serve as a base for a more sophisticated IVM to be used as a research tool.
- Computational particle–haemodynamics analysis of liver radioembolization pretreatment as an actual treatment surrogate(Willey, 2017-02) Aramburu-Montenegro, J. (Jorge); Sangro, B. (Bruno); Bilbao, J.I. (José I.); Ramos-González, J. (Juan Carlos); Rivas-Nieto, A. (Alejandro); Antón-Remírez, R. (Raúl)Liver radioembolization (RE) is a treatment option for patients with unresectable and chemorefractory primary and metastatic liver tumours. RE consists of intra-arterially administering via catheter radioactive microspheres that locally attack the tumours, sparing healthy tissue. Prior to RE, the standard practice is to conduct a treatment-mimicking pretreatment assessment via the infusion of Tc-99m-labelled macroaggregated albumin microparticles. The usefulness of this pretreatment has been debated in the literature, and thus, the aim of the present study is to shed light on this issue by numerically simulating the liver RE pretreatment and actual treatment particle-haemodynamics in a patient-specific hepatic artery under two different literature-based cancer scenarios and two different placements of a realistic end-hole microcatheter in the proper hepatic artery. The parameters that are analysed are the following: microagent quantity and size (accounting for RE pretreatment and treatment),...
- Prototype Thermoelectric Climate System for its Use in Residential Buildings(2010-11-03T07:58:47Z) Martín-Gómez, C. (César); Rivas, A. (Alejandro); Ramos-González, J. (Juan Carlos); Eguaras-Martínez, M. (María); Mambrilla-Herrero, N. (Natalia); Torres-Ramo, J. (Joaquín)The School of Architecture of the University of Navarra has begun a project which consists in constructing a prefabricated module, consisting of a simplified inhabited housing unit, and monitoring over the course of one year the behavior of a thermoelectric installation that provides service to this module. The principal objective of the project is to quantify the response capacity of a thermoelectric climate control system applied to a prototype, and evaluate its energy and economic costs in the case that the system were applied in an apartment building. The development of this project represents the application in the field of construction of a technology that already is in use in other areas, fundamentally the military and aerospace. Therefore, we do not seek to demonstrate the performance of Peltier cells per se, but rather to evaluate how they function when applied to the residential area, and to analyze both the positive and negative aspects of their use. In this regard, it must not be forgotten that Spanish regulations also require the evaluation of the maintenance needs of climate control equipment, and, in this regard, Peltier cells offer an important advantage: Despite the fact that the initial investment is greater than with a conventional method of climate control, the maintenance costs are nearly zero. For these reasons, an objective of the project is to estimate the construction and amortization costs of the application of this technology in the residential area.
- The role of angled-tip microcatheter and microsphere injection velocity in liver radioembolization: A computational particle–hemodynamics study.(Wiley, 2017-12) Aramburu-Montenegro, J. (Jorge); Sangro, B. (Bruno); Bilbao, J.I. (José I.); Ramos-González, J. (Juan Carlos); Rivas-Nieto, A. (Alejandro); Antón-Remírez, R. (Raúl)Liver radioembolization is a promising treatment option for combating liver tumors. It is performed by placing a microcatheter in the hepatic artery and administering radiation-emitting microspheres through the arterial bloodstream so that they get lodged in the tumoral bed. In avoiding nontarget radiation, the standard practice is to conduct a pretreatment, in which the microcatheter location and injection velocity are decided. However, between pretreatment and actual treatment, some of the parameters that influence the particle distribution in the liver can vary, resulting in radiation-induced complications. The present study aims to analyze the influence of a commercially available microcatheter with an angled tip and particle injection velocity in terms of segment-to-segment particle distribution. Specifically, 4 tip orientations and 2 injection velocities are combined to yield a set of 8 numerical simulations of the particle-hemodynamics in a patient-specific truncated hepatic artery. For each simulation, 4 cardiac pulses are simulated. Particles are injected during the first cycle, and the remaining pulses enable the majority of the injected particles to exit the computational domain. Results indicate that, in terms of injection velocity, particles are more spread out in the cross-sectional lumen areas as the injection velocity increases. The tip's orientation also plays a role because it influences the near-tip hemodynamics, therefore altering the particle travel through the hepatic artery. However, results suggest that particle distribution tries to match the blood flow split, therefore particle injection velocity and microcatheter tip orientation playing a minor role in segment-to-segment particle distribution.
- Liver cancer arterial perfusion modelling and CFD boundary conditions methodology: a case study of the haemodynamics of a patient-specific hepatic artery in literature-based healthy and tumour-bearing liver scenarios(Willey, 2016-11) Aramburu-Montenegro, J. (Jorge); Sangro, B. (Bruno); Bilbao, J.I. (José I.); Ramos-González, J. (Juan Carlos); Rivas-Nieto, A. (Alejandro); Antón-Remírez, R. (Raúl)Some of the latest treatments for unresectable liver malignancies (primary or metastatic tumours), which include bland embolisation, chemoembolisation, and radioembolisation, among others, take advantage of the increased arterial blood supply to the tumours to locally attack them. A better understanding of the factors that influence this transport may help improve the therapeutic procedures by taking advantage of flow patterns or by designing catheters and infusion systems that result in the injected beads having increased access to the tumour vasculature. Computational analyses may help understand the haemodynamic patterns and embolic-microsphere transport through the hepatic arteries. In addition, physiological inflow and outflow boundary conditions are essential in order to reliably represent the blood flow through arteries. This study presents a liver cancer arterial perfusion model based on a literature review and derives boundary conditions for tumour-bearing liver-feeding hepatic arteries based on the arterial perfusion characteristics of normal and tumorous liver segment tissue masses and the hepatic artery branching configuration. Literature-based healthy and tumour-bearing realistic scenarios are created and haemodynamically analysed for the same patient-specific hepatic artery. As a result, this study provides boundary conditions for computational fluid dynamics simulations that will allow researchers to numerically study, for example, various intravascular devices used for liver disease intra-arterial treatments with different cancer scenarios.
- Computational study of a novel catheter for liver radioembolization(Wiley, 2022) Aramburu-Montenegro, J. (Jorge); Sanchez-Larraona, G. (Gorka); Sangro, B. (Bruno); Rivas, A. (Alejandro); Bilbao, J.I. (José I.); Ramos-González, J. (Juan Carlos); Antón, R. (Raúl); Ortega, J. (Julio)Radioembolization (RE) is a medical treatment for primary and secondary liver can-cer that involves the transcatheter intraarterial delivery of micron-sized andradiation-emitting microspheres, with thegoal of improving microsphere depositionin the tumoral bed while sparing healthytissue. An increasing number of in vitroand in silico studies on RE in the literature suggest that the particle injection veloc-ity, spatial location of the catheter tip and catheter type are important parameters inparticle distribution. The present in silico study assesses the performance of a novelcatheter design that promotes particle dispersion near the injection point, with thegoal of generating a particle distribution that mimics the flow split to facilitatetumour targeting. The design is based on two factors: the direction and the velocityat which particles are released from the catheter. A series of simulations was per-formed with the catheter inserted at an idealised hepatic artery tree with physiologi-cally realistic boundary conditions. Two longitudinal microcatheter positions in thefirst generation of the tree were studied by analysing the performance of the cathe-ter in terms of the outlet-to-outlet particle distribution and split flow matching. Theresults show that the catheter with the best performance is one with side holes onthe catheter wall and a closed frontal tip. This catheter promotes a flow-split-matching particle distribution, which improves as the injection crossflow increases.
- Performance and feasibility assessment of a hybrid cooling system for office buildings based on heat dissipation panels(Elsevier, 2020) Martín-Gómez, C. (César); Zuaza-Ros, A. (Amaia); Ramos-González, J. (Juan Carlos); Gómez-Acebo, T. (Tomás)Conventional cooling systems in large office buildings typically incorporate evaporative cooling towers, despite the drawbacks of direct evaporation. An alternative approach is based on highly selective innovative surfaces capable of daytime radiant cooling, however, prototypes of these cooling radiators have not yet demonstrated a system capable of cooling an actual building. This paper presents a third approach: A hybrid cooling system designed to partly or completely replace a cooling tower using dry heat dissipation panels. Unlike nocturnal cooling radiators, these panels may be integrated into a facade in a vertical position. The hybrid system is described firstly, where two configurations of the system are considered. Then, an evaluation of the hybrid system in comparison to a conventional system is performed by means of a simulation-based study, resulting that the replacement of a cooling tower by cooling panels increases the annual energy consumption by 3.6% compared to a conventional open circuit cooling tower system. However, the decrease in maintenance costs may reduce the annual operational expenses by over 50%.
- Modeling based on design of thermal management systems for vertical elevation applications powered by lithium-ion batteries(Elsevier, 2016-06) Martin-Martin, L. (Leire); Nieto, N. (Nerea); Gastelurrutia, J.(Jon); Gil, I. (Iñigo); Ramos-González, J. (Juan Carlos); Rivas-Nieto, A. (Alejandro)Environmental sustainability, more efficient use of energy, and active safety concepts are becoming important requirements for the actual elevation sector. In this context IK4-IKERLAN and ORONA have designed an auxiliary energy storage system (ESS) for a residential elevation application based on lithium-ion cells. Safety and specially lifetime are two of the main concerns surrounding this new technology, which is closely related to the cells operating behavior and temperature asymmetries in the complete ESS. Therefore, the temperature of the cells in battery packs (BPs) needs to be controlled in an efficient way. This paper describes the development of the thermal management system (TMS) designed for this application based on various Computational Fluid Dynamics (CFD) mathematical models. The accuracy of Transient model is validated by using a single module to compare the simulation temperature results with experimental measurements, with a maximum time-averaged temperature prediction error of 1.5 degrees C. The proposed design is validated as it fulfills the requirements for a wide operating window, with a maximum cell temperature of 39 degrees C and a thermal dispersion at system level below 3 degrees C for the worst tested case. A more realistic current profile is checked numerically in the worst ambient and operative conditions for different virtual design variants to propose improvements.
- Mono- and multi-diameter approaches to predict stratified flow structure by means of CFD simulations in DAF systems(Elsevier, 2022) Sanchez-Larraona, G. (Gorka); Rivas, A. (Alejandro); Ramos-González, J. (Juan Carlos); Hlukhov, D. (Dmytro)This paper presents a Computational Fluid Dynamics (CFD) model of a pilot scale dissolved air flotation (DAF) tank. A Multiphase Mixture model was used to analyse the influence of bubble sizes on the formation of a stratified flow structure. Critical bubble diameter is defined as the size of the bubble that implies the equality of the bubble rising velocity and flow downward velocity in the separation zone (SZ). The fact as to whether using air bubble sizes which are greater or less than the critical diameter value significantly affects the air content, flow structure and the limit of the whitewater blanket inside the SZ is assessed. The study was carried out using two approaches, namely, mono- and multi-diameter. The results obtained via the mono-diameter approach proved to be closely in line with experimental data when air concentration in the SZ had almost, but not quite, a constant value. However, it failed to predict the case of the progressive decrease in air below half of SZ height. A combined effect of bubbles with different rising speed was required to reproduce a smooth air profile curve, as measured experimentally. In this context, a multi-diameter approach is deemed to be a suitable method for reproducing the stratified structure. In addition, this approach offers the chance to study bubble size distribution inside the SZ domain.