Artículos (Ingeniería y Ciencia de los Materiales y del Transporte)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/11377

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Enhancing corrosion resistance and bioactive behavior of porous metallic scaffolds through electrochemical coatings
(Elsevier, 2025-03) Rosa Melián, Julio Ernesto de la; García Cabezón, Cristina; García-Hernández, Celia; Delgado-Pujol, Ernesto J.; García-García, Francisco J.; Boccaccini, Aldo R.; Martín Pedrosa, Fernando; Torres Hernández, Yadir; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía; Universidad de Sevilla. TEP123: Metalurgia e Ingeniería de los Materiales
The percentage and size of the pores obtained by conventional powder metallurgy route, as well as corrosion phenomena and poor bioactivity, limit the clinical success of porous metallic implants. In this work, a joint solution is proposed, combining the manufacture of bone implants by the loose sintering technique (economical, repetitive and maximized porosity), coated with chitosan-bioactive glass bio-composites synthesized by chronoamperometry and electrophoresis techniques. The influence of porosity on the biomechanical and biofunctional behavior of titanium substrates is evaluated, as well as the role of bioactive coatings in improving their corrosion resistance and osteoinduction capacity. These electrochemical methods are optimized and presented as a promising strategy for developing uniform protective coatings. Biodegradable coatings based on chitosan are replaced by calcium phosphates that form on the surface of the implants, promoted by the effect of bioactive glass reinforcements (BG-45S5 and BG-1393). Chitosan-bioactive glass composite coatings significantly improved the corrosion resistance of titanium substrates. Loose sintering samples exhibited a 94 % reduction in corrosion current density reaching 1.08·10–6 A/cm2 and a polarization resistance of 14·103 Ω/cm2 with BG-1393. The in vitro bioactivity study confirmed apatite formation after immersion in SBF, with a Ca/P ratio close to natural hydroxyapatite (1.67), particularly for chitosan with BG-45S5 (achieving 1.76).
Characterization of pea protein-based bioplastics processed by injection moulding
(Elsevier, 2016-01) Pérez-Puyana, Víctor Manuel; Félix Ángel, Manuel; Romero García, Alberto; Guerrero Conejo, Antonio Francisco; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Economía y Competitividad (MINECO). España; Junta de Andalucía; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
This study assesses the behaviour of pea protein isolate (PPI) as a potential candidate for the development of biobased plastic materials processed by injection moulding. Around 30–40% of glycerol as plasticizer was required to obtain good processability of PPI/GL blends to produce bioplastics. A mixing rheometer that allows recording of torque and temperature during mixing and a small-scale-plunger-type injection moulding machine were used to obtain PPI/GL blends and PPI-based bioplastics, respectively. Rheological and differential scanning calorimetry measurements were made to guide the selection of suitable conditions for injection and moulding. For injection, we selected a temperature relatively close to the maximum of the loss tangent, but moderate enough to avoid crosslinking effects (50 °C), and for moulding, a high temperature (130 °C) to favour crosslinking in the mould. An increase in the PPI/GL ratio leads to an enhancement of elastic bending and tensile properties of bioplastic specimens, as well as an increase in their ability to absorb mechanical energy before rupturing. On the other hand, the PPI/GL specimens become less transparent. In addition, water uptake of these bioplastics has been found to be very high and fast.
Effect of the injection moulding processing conditions on the development of pea protein-based bioplastics
(Wiley, 2016-02-05) Pérez-Puyana, Víctor Manuel; Félix Ángel, Manuel; Romero García, Alberto; Guerrero Conejo, Antonio Francisco; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Economía y Competitividad (MINECO). España; Junta de Andalucía; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
Bioplastic materials from renewable polymers, like proteins, constitute a highly interesting field for important industrial applications such as packaging, agriculture, etc., in which thermo-mechanical techniques are increasingly being used. Pea protein-based bioplastics can be made through a mixing process followed by an injection moulding. The objective of this study was to investigate the influence of different injection parameters (moulding time and injection pressure) on the properties exhibited by the final bioplastics obtained. A dynamic mechanical analysis and tensile strength measurements were performed, along with water absorption capacity and transparency tests. The results indicated that the major differences between bioplastics obtained at different moulding times are in transparency and in the Young's Moduli, exhibiting lower values as moulding time increases. On the other hand, modifying the injection pressure lead to more consistent bioplastics which differed mainly in the elastic component (E′ profiles) and in the strain at break. Furthermore, the water uptake was more than 100% in almost all the different bioplastics processed because of its hydrophilic character, so they could be considered as potential sources for absorbent material.
Development of thermally processed bioactive pea protein gels: Evaluation of mechanical and antioxidant properties
(Elsevier, 2017-01) Félix Ángel, Manuel; Pérez-Puyana, Víctor Manuel; Romero García, Alberto; Guerrero Conejo, Antonio Francisco; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Junta de Andalucía; Ministerio de Economía y Competitividad (MINECO). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
Thermal processing of plant proteins (e.g. from pea) is highly interesting due to its potential in the generation of new textures in food products. This processing route is particularly attractive when it is combined with the revalorization entailed by the bioactive properties of the processed gels. In fact, the antioxidant activity of food products, which has been found in numerous proteins and peptides from protein hydrolysates, is widely demanded by the society since it prevents the development of serious diseases. This work is focused on the evaluation of mechanical and antioxidant properties from a Pea Protein Concentrate (PPC) and two hydrolysates obtained from PPC (PPH₂₅ and PPH₁₂₀) at three different pH values (2.0, 6.5 and 8.0). The gelation process was monitored and, subsequently, mechanical spectra were obtained. In addition, protein interactions (ionic interactions, hydrophobic interactions, hydrogen bonds and disulphide bonds) were also determined in order to elucidate their contribution to the formation of the gel network. Finally, the characterisation of the antioxidant activity of the gels was carried out using three different reagents: DPPH, ABTS and Folin–Ciocalteu. Results put forward that each variable studied, the degree of hydrolysis and pH, are key factors over the thermal processing of gels, showing a remarkable influence on both mechanical properties and antioxidant activity.
Evaluation of the injection moulding conditions in soy/nanoclay based composites
(Elsevier, 2017-10) Bourny, Valentin; Félix Ángel, Manuel; Pérez-Puyana, Víctor Manuel; Romero García, Alberto; Guerrero Conejo, Antonio Francisco; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Economía y Competitividad (MINECO). España; Universidad de Sevilla; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
Biocomposites, and generally bio-based plastics, are seen as a promising alternative to conventional plastics because they are based on renewable natural components (eco-friendly) with a lower cost. Biocomposites using soy protein and glycerol were obtained with an injection moulding technique as the thermoprocessing method. Nanoclay (Montmorillonite, MMT-Na⁺) was included to improve physicochemical properties of novel SPI/MMT nanocomposites prepared by injection moulding, primary attending to water uptake capacity (WUC), but also considering rheological and mechanical properties. The influence of processing conditions has been studied in order to assess the modifications taking place in the microstructure and properties of these nanocomposites. Addition of MMT-Na⁺ improves mechanical properties and WUC of SPI-based materials, depending on processing conditions. Injection pressure only exerts a slight enhancement of mechanical properties and WUC. However, an increase in mixing time leads to a relevant increase in WUC without impairing the mechanical properties of nanocomposites.
Development of protein-based bioplastics modified with different additives
(Wiley, 2017-11-05) Félix Ángel, Manuel; Pérez-Puyana, Víctor Manuel; Romero García, Alberto; Guerrero Conejo, Antonio Francisco; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Economía y Competitividad (MINECO). España; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
Proteins have been postulated as a feasible source for manufacturing biodegradable polymeric materials. The aim of this study is the development of bioplastic materials from two different protein sources: albumen protein isolated (API), which consists of globular proteins, and crayfish flour (CF), mostly composed of myofibrillar proteins. In order to explore the effect of some chemical reagents on the mechanical properties of the blends and bioplastic materials, two different additives have been used: sodium sulfite (SS) and urea (U). The first one is a reducing agent, and the second one is considered a denaturing agent. The addition of chemical agents induces changes not only in mechanical properties but also in the most suitable processing conditions, which strongly depends on the protein used. Thus, the denaturation of globular proteins seems to lead to a more consistent blend before the injection-molding process. However, when myofibrillar proteins are used, the processability of the dough-like material increases after using either SS or U additives. This work illustrates the feasibility of producing animal-based biodegradable bioplastic materials with different properties and, consequently, different applications, which contribute to adding a high value to two different byproducts from the food industry.
Development of eco-friendly biodegradable superabsorbent materials obtained by injection moulding
(Elsevier, 2018-10) Pérez-Puyana, Víctor Manuel; Félix Ángel, Manuel; Romero García, Alberto; Guerrero Conejo, Antonio Francisco; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Economía y Competitividad (MINECO). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
The development of eco-friendly materials requires a deep knowledge of physical, chemical and functional properties of biopolymers and fillers. Soy protein (SPI), which is one of the cheapest protein in global markets, was used in combination with montmorillonite (MMT-Na+) to obtain fairly attractive green biocomposite superabsorbent materials, leading to biodegradable superabsorbent materials. Natural MMT-Na+ was used since it is widely available as micron-size tactoids and gives rise to highly functional nanoparticles. However, the dispersion of such particles within a polymer structure is complex, showing a high impact on techno-functional properties. An easy-scalable processing technique was used with a mixing stage to obtain dough-like materials which were subjected to an injection-moulding process that led to biodegradable biocomposite materials. The structure of dough-like materials was characterized by scanning electron microscopy and X-Ray diffraction, whereas mechanical properties of green biocomposites were evaluated by dynamic mechanical analysis (DMA) and tensile tests. Moreover, the techno-functionality of the new materials obtained was determined by means of water uptake capacity (WUC). Results suggested that the addition of nanoclay led to an increase of the elastic modus although the overall improvement of mechanical properties is not clear. Interestingly, water uptake capacity was greatly enhanced. In this sense, these green biocomposites could be considered as an excellent candidate for the development of novel bio-based superabsorbent materials.
Use of a mixer-type rheometer for predicting the stability of O/W protein-based emulsions
(Elsevier, 2017-11) Romero García, Alberto; Félix Ángel, Manuel; Pérez-Puyana, Víctor Manuel; Choplin, Lionel; Guerrero Conejo, Antonio Francisco; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Economía y Competitividad (MINECO). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
The present work illustrates the feasibility of performing Oil-in-Water (O/W) emulsions stabilized by different protein concentrates, as well as predicting the likelihood of emulsion destabilization over ageing time just after its preparation. To achieve this objective, four protein sources (rice, crayfish, potato and albumen) and four oil concentrations (450, 550, 650 and 750 g kg⁻¹) were used. The emulsification process was monitored by the use of a mixer-type rheometer. This rheometer was a valuable tool for understanding and controlling the emulsification process through the measurement of the viscosity of the different systems during the emulsification stage. Results reveal the importance of controlling the emulsification process to optimize the properties of the final emulsion, which is highly influenced by the oil concentration. Then, emulsions were characterized by means of flow properties and droplet size distribution (DSD). Eventually, a relationship was found that relates the rheological properties and the microstructure of the final emulsions during and after emulsification stage. These measurements have been demonstrated to be useful in order to predict the stability of protein-based emulsions.
Reactivity of aragonite with dicalcium phosphate facilitates removal of dental calculus
(Springer, 2025) Elhadad, Amir A.; Basiri, Tayebeh; Al-Hashedi, Ashwaq; Smith, Sophia; Moussa, Hanan; Veettil, Sadiya; Pérez-Soriano, Eva María; Tamimi, Faleh; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte
Dental calculus, a main contributor of periodontal diseases, is mostly composed of inorganic calcium phosphate species such as dicalcium phosphate, whitlockite, octa calcium phosphate, and hydroxyapatite. Under physiological pH 7.4, dicalcium phosphates can gradually interact with calcium carbonate to form hydroxyapatite. Therefore, we hypothesized that aragonite (Arg) could react with dental calculus, facilitating its removal. To assess the reactivity of Arg with dental calculus, we examined the changes in surface morphology, composition, and topography of Arg and dental calculus upon exposure to each other in an aqueous environment. The impact of Arg on the removal of dental calculus was assessed by brushing polished sections of dental calculus, enamel, and dentin with slurries of Arg and measuring the depth of abrasion using a stylus profilometer. Our results demonstrate that Arg can react with dental calculus in aqueous environment. This reaction increases calculus surface roughness which in turn facilitate dental calculus removal by brushing. Aragonite could be a promising abrasive for toothpaste design for management of dental calculus.
Enhancing the matrix-fiber bond in ultra-high-performance fiber-reinforced concrete using a high performance plasticizer. Impact on the flowability, physical and mechanical properties
(Elsevier, 2025) Ruiz Martínez, Jaime D.; Ríos Jiménez, José David; Pérez-Soriano, Eva María; Cifuentes Bulté, Héctor; Leiva Fernández, Carlos; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Sevilla. Departamento de Mecánica de Medios Continuos y Teoría de Estructuras; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla. TEP972: Mecánica de Materiales y Estructuras; Universidad de Sevilla. TEP118: Ingeniería de los Transportes; Universidad de Sevilla. TEP123: Metalurgia e Ingeniería de los Materiales; Universidad de Sevilla. TEP142: Ingeniería de Residuos
One of the main problems in the use of ultra-high-performance fiber-reinforced concrete (UHPFRC) with steel fibers is low flowability. The addition of 2,3,4,5,6-Pentahydroxycaproic acid sodium salt (SPS) in small amounts (0.05, 0.1 and 0.15 %wt of the cement content) can significantly increase the flowability and setting time. The effects on porosity, matrix chemical composition and fiber-matrix interaction were examined, as well as its influence on strength. Improving the flowability, pores larger than 50 μm show a significant decrease, while those smaller than 0.1 μm show a significant increase. According to the results of thermo-gravimetric analysis, the production of ettringite with finer grains and staggered symbiosis improves the pore structure of the UHPFRC matrix. An improvement of the adhesion of the steel fibers to the matrix was determined by stereomicroscope images, showing evidence of a relationship between SPS dosage and the expanded concrete area surrounding the fiber. The flexural and compressive strength increased by 10 % and 8 %, respectively, when the plasticizer/cement ratio was 0.15 %.
Enrichment Methods for Metal Recovery from Waste from Electrical and Electronic Equipment: A Brief Review
(MDPI, 2025) Chicardi Augusto, Ernesto; López-Paneque, Antonio; Gallardo García-Orta, Victoria Humildad; Sepúlveda Ferrer, Ranier Enrique; Gallardo Fuentes, José María; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; EIT Raw Materials
The growing global demand for minerals and metals, coupled with fluctuations in pricing and market disruptions, has emphasised the critical role of these resources in sustaining the global economy. Waste from Electrical and Electronic Equipment (WEEE) has emerged as a promising source of raw materials, particularly for metal recycling and the valorisation of plastic fractions. In 2022, approximately 62 million metric tons of e-waste were generated worldwide, with projections indicating a rise to 74 million metric tons by 2030. Despite the significant volume of WEEE, only 17.4% was collected and recycled, which reveals a considerable opportunity for resource recovery. This review highlights the composition of metals in WEEE, which includes valuable precious metals, such as gold, silver, and palladium, alongside base metals, such as copper and aluminium. The review also discusses current methodologies for metal recovery and focuses on mechanical size-reduction techniques and various physical separation methods, including a shaking table, magnetic, electrostatic, and eddy current separation, flotation, and the use of a hydrocyclone. These technologies play a vital role in enhancing recovery efficiencies, thereby contributing to sustainable practices in the recycling industry. Thus, the works evaluated in this paper reveal the possibility of recovering more than 90 wt.% of precious (Ag, Au, Pd, Pt) and main metals (Cu, Sn, Al, Fe, Ni) by a combination of these mechanical size-reduction and physical separation methods.
Efect of nano silicon nitride on the microstructural characteristics and mechanical properties of ultra‑high‑performance steel fber reinforced concrete
(Springer Nature, 2025) Ruiz Martínez, Jaime D.; Ríos Jiménez, José David; Pérez-Soriano, Eva María; Cifuentes-Bulté, Héctor; Leiva Fernández, Carlos; Universidad de Sevilla. Departamento de Ingeniería Química y Ambiental; Universidad de Sevilla. Departamento de Mecánica de Medios Continuos y Teoría de Estructuras; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla. TEP142: Ingeniería de Residuos; Universidad de Sevilla. TEP123: Metalurgia e Ingeniería de los Materiales; Universidad de Sevilla. TEP972: Mecánica de Materiales y Estructuras
This study investigates the incorporation of an innovative nano-reinforcement, nano silicon nitride (NSIN), to enhance the workability and mechanical performance of ultra-high-performance fber reinforced concrete. The addition of NSIN at dosages of 0.25, 0.5, 0.75, and 1.5 wt% of cement was analyzed to evaluate its impact on the distribution and interaction between steel fbers and the cementitious matrix. Experimental analyses, including thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), were conducted to establish a relationship between the microstructural modifcations, fber-matrix interactions, and the resulting mechanical behavior. The fndings revealed that NSIN increased workability and extended setting time, enabling improved steel fber dispersion and interaction
Influence of the processing variables on the microstructure and properties of gelatin-based scaffolds by freeze-drying
(Wiley, 2019-02-23) Pérez-Puyana, Víctor Manuel; Félix Ángel, Manuel; Romero García, Alberto; Guerrero Conejo, Antonio Francisco; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Economía, Industria y Competitividad, España; Universidad de Sevilla; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
In the last few years, the field of tissue engineering has suffered an exponential growth, and although it is true that the processing parameters affect the properties of the scaffolds, only a few studies have investigated that statement. For that reason, the influence of different parameters involved in the freeze-drying process (container, freezing temperature, pH, and solvent used) on the mechanical and structural properties of gelatin-based scaffolds was analyzed in this study. Thus, rheological measurements and porosity analyses were performed to evaluate the scaffolds obtained. Results indicate that the parameters evaluated modify the mechanical properties of the scaffold, highlighting the option of a plastic mold to contain an acidic protein solution produced using a weak acid (acetic acid) at low concentration (0.05 M) as solvent. On the contrary, only the pH and the freezing temperature led to significant differences in the porosity of these scaffolds, obtaining values higher than 95% for all the systems studied. These results are useful to demonstrate that the control of the different parameters implied in the processing technique allows designing a scaffold with specific properties suitable for different applications.
Experimental study of the use of a transfer function to find rail corrugation from axle-box accelerations
(Elsevier, 2025-05) Yu, Xinxin; Muñoz Moreno, Sergio; Urda Gómez, Pedro; Fernández Aceituno, Javier; Rodríguez Gómez, Miguel; Escalona Franco, José Luis; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. Departamento de Ingeniería Mecánica y Fabricación; Consejería de Economía, Ciencia, Empresa y Universidades. Junta de Andalucía; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Universidad de Sevilla. TEP111: Ingeniería Mecánica; Universidad de Sevilla. TEP123: Metalurgia e Ingeniería de los Materiales
This investigation uses a scale vehicle-track experimental facility to study the calculation of rail corrugation using vertical accelerations measured in the axle-box of rail vehicles and a transfer function (TF). The rail corrugated profile is machined in the rail heads of the scale track following a periodic function with four harmonics. Experiments are performed with a scale bogie-like vehicle at different forward velocities in the range inspection velocities. Two simple analytical forms of the TF are studied: the kinematic TF, that assumes that the axle box follows the rail profile, and the TF of a 2-dof model of the vehicle-track system. For the vehicle response analysis, this work proposes to normalize the measured acceleration with the square of the forward velocity of the vehicle, that is assumed to be approximately constant. This normalized acceleration reduces the effect of the forward velocity on the TF. Experimental results show that the kinematic TF can be used to measure the track corrugation for moderate forward velocities providing reasonable but not accurate results. The limitation of the kinematic TF is mainly due to free flights and wheel rail curvature incompatibility. The measured axle-box accelerations may include frequency peaks that are not excitation frequencies and can distort the rail profile measurement. Results show that linear elastic models like the assumed 2-dof model do not explain the appearance of these non-excitation peaks.
Silk-Sericin Release from Polymeric Scaffold as Complementary Dermocosmetic Treatment for Acne
(MDPI, 2025-03-14) Vargas González, Arianna; Pérez Ramos, Patricia; Pérez-Soriano, Eva María; Sola Dueñas, Francisco Javier; Pérez Almazán, Denise; García Couce, Jomarien; Fuentes Estévez, Gastón; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. TEP123: Metalurgia e Ingeniería de los Materiales
Currently, acne therapy relies not only on specific drugs but also on complementary treatments, such as dermocosmetics. Several studies have reported the use of chitosan and alginate in scaffolds for drug delivery systems. These materials can be loaded with a product that exhibits anti-acne properties such as silk sericin, a protein with antioxidant, photoprotective, and moisturizing properties. Therefore, this study proposes the development of a chitosan/alginate scaffold, loaded with sericin, to serve as a dermocosmetic platform complementing the pharmacological treatment of acne. The moisture content of the alginate and chitosan was determined as 14.7 and 21%, respectively; the ash content, which is similar for both polymers, was approximately 5%. The employed chitosan had a deacetylation degree of 82%, as determined by infrared spectrometry and corroborated by potentiometry. This technique was also used to determine the mannuronic/guluronic ratio of the alginate [M/G = 1.3] and confirm the identity of each one of the polymers in the raw materials and the resulting scaffolds. The molecular weights of alginate, chitosan, and sericin were 85, 5.1, and 57.4 kDa, respectively. The pH [6.31] and total protein concentration of the sericin solution [c(SER) = 6.1 mg/mL] were determined using UV-visible spectrophotometry. Swelling and release studies indicated that, although there were varying degrees of cross-linking and certain variables to control, the mechanism that defines the nature of both processes (otherwise complementary) is the relaxation of the polymer chains.
Influence on the properties of TMCs of ceramic and intermetallic composite reinforcements (B₄C, TiₓAly and TiₓSiy) fabricated by inductive hot pressing
(Elsevier, 2024-09-30) Arévalo Mora, Cristina María; Montealegre-Meléndez, Isabel; Neubauer, Erich; Kitzmantel, Michael; Lascano, Sheila; Pérez-Soriano, Eva María; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. TEP123: Metalurgia e Ingeniería de los Materiales
Ambitious and competitive, the aerospace industry continuously demonstrates to be one of the leading engineering sectors either at exigence and new technologies development. As lightning the weight of aircrafts is one of the main targets, the spotlight is usually on material research by which new ones may be produced to pursue this aim and still offer the necessary performances. The combination of the properties of titanium and other materials as reinforcements provides really interesting results as titanium matrix composite materials, also known as TMCs. Various samples of titanium matrix composite materials with different reinforcements have been under study to determine the influence of the reinforcements and their respective proportions on the properties of the material. These samples composed of grade 1 commercially-pure titanium as matrix and B₄C, TiₓAly and TiₓSiy as reinforcements, have been manufactured through powder metallurgy in the same conditions of temperature and pressure via Inductive Hot Pressing (IHP). A total of eight composite materials have been arranged in several different groups to confront their compositions. Thus, this analysis reports results for the influence of the powder size of the matrix and the ceramic reinforcement, the effect of varying the volumetric composition of B₄C, and the selection of different intermetallic reinforcements. These tests and the obtained information serve for a project in which the main goal is to determine which compositions of the studied composite materials reach a high enough specific stiffness for a suitable application in the aerospace industry.
Alloy exsolution in co-doped PrBaMn₂₋ₓTMₓO₅+δ (TM = Co and/or Ni) obtained by mechanochemistry
(Elsevier, 2024-12-15) Gotor Martínez, Francisco José; Sayagués de Vega, María Jesús; Marrero-López, D.; García García, Francisco José; García García, Francisco José; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC); Universidad de Sevilla. TEP123: Metalurgia e Ingeniería de los Materiales
Doped-PrBaMn₂₋ₓTMₓO₅+δ samples with TM = Co and/or Ni were synthesized by a mechanochemical route from stoichiometric oxide precursor mixtures (Pr₆O₁₁, BaO₂, MnO, NiO and CoO) using a planetary mill at 600 rpm for 150 min. A disordered ABO₃ pseudocubic perovskite phase was obtained after the milling process that was transformed, as established by XRD, into the double layered AA’B2O₅+δ perovskite phase after annealing at 900 °C in a reducing atmosphere (10%H₂/Ar). The microstructural characterization by SEM, TEM, and HRTEM ascertained that this reducing treatment induced the exsolution of Ni and Co metallic nanoparticles from the doped samples. Ni-Co alloys were even exsolved when the layered manganite phase was co-doped with both transition metals. It was confirmed that the exsolution process was reversible by switching the working atmosphere from reducing to oxidizing. Polarization resistance values of the doped samples determined in symmetrical cells in air and H₂, as well as the electrochemical performance of electrolyte LSGM-supported planar cells suggested that these samples can be used as symmetrical electrodes in SOFCs.
Enabling low molecular weight electrospinning through binary solutions of polymer blends
(Elsevier, 2025-01) Pérez-Puyana, Víctor Manuel; Romero García, Alberto; Guerrero Conejo, Antonio Francisco; Moroni, Lorenzo; Wieringa, Paul; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Economía y Competitividad (MINECO). España; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
The formation of nanofibrous membranes via electrospinning is typically restricted to high molecular weight polymers in an appropriate solvent, correlated with the necessary formation of polymer chain entanglements that are needed to achieve successful production of electrospun fibers. The present work extends the electrospinning of low molecular weight polymers by investigating the electrospinning of a binary solution system consisting of two different low molecular weight polymers, using as a model system polycaprolactone (PCL) and gelatin in different ratios. The viscosities of the polymer solutions were characterized as a proxy for polymer chain entanglement and the resulting fibers were morphologically characterized by SEM imaging and further assessed water contact angle and molecular composition to determine the impact and homogeneity of the binary mixtures. We found that unitary solutions of either PCL or gelatin failed to generate proper fibers despite indications of chain entanglement. In contrast, binary solutions of low molecular weight PCL and gelatin generated different fiber quality and size distributions, depending on the ratio used, with direct correlations between fiber properties and the PCL:Gelatin ratio. It was discovered that the ratio of PCL to gelation was most predictive for successful fiber generation, with effective electrospinning occurring only for a define intermediate range of high blend ratios while both low and high blended binary solutions resulted in poor fiber production. Our study confirmed that this behavior was independent from absolute polymer concentration, indicating a unique interaction between these binary species which exists only under specific ratio concentrations and indicates promising new avenues to process low molecular weight polymers solutions.
Hydrogels and Nanogels: Pioneering the Future of Advanced Drug Delivery Systems
(MDPI, 2025-02-07) Delgado-Pujol, Ernesto J.; Martínez Muñoz, Guillermo; Casado Jurado, David; Vázquez Cabello, Juan; León-Barberena, Jesús; Rodríguez Lucena, David; Torres Hernández, Yadir; Alcudia Cruz, Ana; Begines Ruiz, Belén; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. Departamento de Química Orgánica y Farmacéutica; Universidad de Sevilla. Departamento de Química Orgánica; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla. TEP123: Metalurgia e Ingeniería de los Materiales; Universidad de Sevilla. FQM408: Química Farmacéutica Aplicada
Conventional drug delivery approaches, including tablets and capsules, often suffer from reduced therapeutic effectiveness, largely attributed to inadequate bioavailability and difficulties in ensuring patient adherence. These challenges have driven the development of advanced drug delivery systems (DDS), with hydrogels and especially nanogels emerging as promising materials to overcome these limitations. Hydrogels, with their biocompatibility, high water content, and stimuli-responsive properties, provide controlled and targeted drug release. This review explores the evolution, properties, and classifications of hydrogels versus nanogels and their applications in drug delivery, detailing synthesis methods, including chemical crosslinking, physical self-assembly, and advanced techniques such as microfluidics and 3D printing. It also examines drug-loading mechanisms (e.g., physical encapsulation and electrostatic interactions) and release strategies (e.g., diffusion, stimuli-responsive, and enzyme-triggered). These gels demonstrate significant advantages in addressing the limitations of traditional DDS, offering improved drug stability, sustained release, and high specificity. Their adaptability extends to various routes of administration, including topical, oral, and injectable forms, while emerging nanogels further enhance therapeutic targeting through nanoscale precision and stimuli responsiveness. Although hydrogels and nanogels have transformative potential in personalized medicine, challenges remain in scalable manufacturing, regulatory approval, and targeted delivery. Future strategies include integrating biosensors for real-time monitoring, developing dual-stimuli-responsive systems, and optimizing surface functionalization for specificity. These advancements aim to establish hydrogels and nanogels as cornerstones of next-generation therapeutic solutions, revolutionizing drug delivery, and paving the way for innovative, patient-centered treatments.
Simulation of the electrical resistance sintering process by means of fnite diference in a spreadsheet
(Springer, 2025) Montes Martos, Juan Manuel; Ternero Fernández, Fátima; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE)
In this work, a theoretical model for the metal powder consolidation technique known as Electrical Resistance Sintering (ERS) is proposed and validated. This technique consists of the consolidation of a mass of metal powder by the simultaneous action of pressure and the passage of a high intensity electric current. This electric current heats the powder mass by the Joule effect, while softening it so that the imposed pressure causes its densification. The proposed model meets the set objective of seeking the greatest possible simplicity, without ignoring the key aspects of the technique. In line with this simplicity, the proposed model has a one-dimensional character and is solved numerically by means of Finite Difference through a simulator implemented in the Microsoft Excel™ spreadsheet environment, programming in VBA, with computation times not exceeding 5 min. The adopted strategy takes into account the strong electrical–mechanical-thermal coupling present in the process. The sensors incorporated in the ERS equipment allow the recording of the data necessary to construct the evolution curves of the global porosity and the thermal energy released. The theoretical predictions provided by the simulator have been compared with experimental curves obtained from the electrical consolidation experiments with commercially pure iron powder. Discrepancies between experimental and theoretical values for final global porosity are around 5% (although approaching 20% in the vicinity of critical conditions) and those for final specific thermal energy do not exceed 7%. The reasonable agreement between the experimental and theoretical curves gives confidence that the model, despite its simplifications, reproduces the main characteristics of the process.

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