Artículos de revista DCIE - ZIES Aldizkari artikuluak

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Open Access
Exploring the complex interplay of anisotropies in magnetosomes of magnetotactic bacteria
(American Chemical Society, 2025-04-14) Gandía Aguado, David; Marcano, Lourdes; Gandarias, Lucía; Gubieda, Alicia G.; García-Prieto, Ana; Fernández Barquín, Luis; Espeso, José Ignacio; Martín Jefremovas, E.; Orue, Iñaki; Abad Díaz de Cerio, Ana; Fernández-Gubieda, María Luisa; Alonso Masa, Javier; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
Magnetotactic bacteria (MTB) are at the forefront of interest for biophysics applications, especially in cancer treatment. Magnetosomes biomineralized by these bacteria are high-quality magnetic nanoparticles that form chains inside the MTB through a highly reproducible, naturally driven process. In particular, Magnetovibrio blakemorei and Magnetospirillum gryphiswaldense MTB exhibit distinct magnetosome morphologies: truncated hexa-octahedral and cuboctahedral shapes, respectively. Despite having identical compositions (magnetite, Fe3O4) and dimensions within a similar size range, their effective uniaxial anisotropies significantly differ at room temperature, with M. blakemorei exhibiting ∼25 kJ/m3 and M. gryphiswaldense ∼ 11 kJ/m3. This prominent anisotropy variance provides a unique opportunity to explore the role of magnetic anisotropy contributions in the magnetic responses of these magnetite-based nanoparticles. This study systematically investigates these responses by examining static magnetization as a function of temperature (M vs T, 5 mT) and magnetic field (M vs μ0H, up to 1 T). Above the Verwey transition temperature (∼110 K), the effective anisotropy is dominated by the shape anisotropy contribution, notably increasing the coercivity for M. blakemorei by up to twofold compared to M. gryphiswaldense. However, below this temperature, the effective uniaxial anisotropy rapidly increases in a nonmonotonic way, significantly changing the magnetic behavior. Computational simulations using a dynamic Stoner–Wohlfarth model provide insights into these phenomena, enabling careful interpretation of experimental data. According to our simulations, below the Verwey temperature, a uniaxial magnetocrystalline contribution progressively emerges, peaking around 22–24 kJ/m3 at 5 K. Our study reveals the complex evolution of magnetocrystalline contributions, which dominate the magnetic response of magnetosomes below the Verwey temperature. This demonstrates the profound impact of anisotropic properties on the magnetic behaviors and applications of magnetite-based nanoparticles and highlights the exceptional utility of magnetosomes as ideal model systems for studying the complex interplay of anisotropies in magnetite-based nanoparticles.
Open Access
Ni-Mo2C/y-Al2O3 catalysts for syngas production in pyrolysis-dry reforming of plastics - the effect of amine nature on catalyst performance
(Elsevier, 2025-05-29) Pawelczyk, Ewelina; Frackiewicz, Izabela; Gil Bravo, Antonio; Karczewski, Jakub; Maciejewski, Michał E.; Dymerski, Tomasz; Gebicki, Jacek; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
Pyrolysis combined with dry reforming (PCDR) is eco-friendly technology for plastic waste management, allowing for sustainable production of syngas. Design of suitable catalysts with high performance and stability is crucial for its industrialization. In this work, Ni-Mo2C/γ-Al2O3 catalysts were synthesized using organic–inorganic precursors. Three types of amines (hexylamine – aliphatic linear, cyclohexylamine – aliphatic cyclic, aniline – aromatic) were used as carbon source in the precursor preparation to investigate their effect on catalyst physicochemical properties and its catalytic performance. Catalytic performance of the obtained catalysts was examined in PCDR of model waste plastic mixture. It was revealed that catalytic activity of catalysts prepared with aliphatic amines was higher compared to aromatic aniline, amine commonly used for carbide synthesis. The differences in catalyst properties, which affected their catalytic activity were characterized using N2-adsorption at −196 °C, XRD, H2-TPR, SEM, TG/DTG and CO2-adsorption methods. A correlation was observed between amine molecule complexity and Mo2C crystallite size, significantly affecting hydrogen generation. The less complex the amine, the smaller the crystallite and the increased hydrogen production. Moreover, the use of aliphatic amines resulted in the stronger Ni-support interactions, the increased number of more favorable, larger mesopores as well as the presence of the metallic Mo phase and the lack of unbound carbon in contrast to the catalyst obtained using aniline. The catalyst synthesized using hexylamine increased H2 yield by more than tenfold, syngas yield by more than threefold, and the H2/CO ratio by fivefold, which offers an opportunity for future industrialization of PCDR.
Open Access
UV-photoelectron spectroscopy and MS-CASPT2/CASSCF study of the thermolysis of azidoethyl-methyl sulfide: Characterization and mechanism of the formation of S-methyl-N-sulfenylethanimine
(American Institute of Physics (AIP), 2025-05-16) Algarra González, Manuel; Labat, Stephane; Rodríguez-Borges, José Enrique; Pino-González, María Soledad; Sotiropoulos, Jean Marc; Soto, Juan; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
The thermal decomposition of azidoethyl methyl sulfide was studied by real-time UV-photoelectron spectroscopy (UV-PES) at temperatures ranging from 773 to 1023 K. Different ionization energies were obtained using density functional theory calculations to assign UV-PES spectra. The complete active space self-consistent field and multistate second-order perturbation methods were used to predict the formation of different species present in the thermal decomposition process. N2 and S-methyl-N-sulfenylethanimine are generated at 773 K. The first step of the reaction is the dissociation of the molecule into nitrene and nitrogen. The spin state (singlet or triplet) of nitrene formed in the first step of the reaction is temperature-dependent. At low temperatures (T ≤ 650 K), both states are formed with almost the same probability; in contrast, at high temperatures (T ≤ 1000 K), singlet nitrene is the majority intermediate. From this singlet nitrene, three stable reaction products were detected in the experiments: an imine derivative, a four-member cyclic derivative, and a sulfenyl derivative.
Open Access
Transfering sustainability competences through green pedagogies and service-learning in higher education
(European Center of Sustainable Development, 2025-02-01) Cantalejo Díez, María Jesús; Martínez Aldaya, Maite; Navarlaz Fernández, Isabel; Ciencias; Zientziak; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura
Sustainability competences are reflected in the ability to look ahead to change and shape the future of the societies in which they live through active participation in the sense of sustainable development. Through service-learning, students take responsibility for their actions. The complex nature of sustainability issues makes it useful to explore problems and their solutions holistically. In the framework of the NEMOS project (A New Educational Model for Acquiring Sustainability Competences through Service-Learning), a collaborative process was initiated to pool the knowledge and experience of five Higher Education Institutions working together to implement new educational models for effectively acquiring sustainability competences through service-learning in food-related degrees. This EU-funded project was launched and aimed to advance the transition to sustainability education through practical and innovative educational approaches and interventions. Green pedagogy can support transformative learning through the exploration and clarification of learners
Open Access
Metal-free nanostructured-carbon inks for a sustainable fabrication of zinc/air batteries: from ORR activity to a simple prototype
(Wiley, 2024-08-14) Santos, Florencio; Lorca, Sebastián; González-Martínez, Juan F.; Urbina Yeregui, Antonio; Álvarez-Sánchez, Miguel A. ; González-Domínguez, José M.; García-Bordejé, Enrique; Ansón-Casaos, Alejandro; Benito, Ana M.; Maser, Wolfgang K.; Fernández Romero, Antonio J.; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
Zinc/air batteries are convenient energy storage devices for both small and massive applications. While future perspectives indicate the need for low-cost components and sustainable fabrication processes, the battery performance is in part controlled by the kinetics of the oxygen reduction reaction (ORR), which typically involves transition metals as catalysts. In this context, we prepare a series of metal-free water-based carbon inks, which are tested for their catalytic performance, once deposited on a gas-diffusion substrate, in the air cathode of a simple battery prototype. The inks contain a variety of well-defined carbon nanomaterials and additives, exhibiting different physicochemical properties that critically influence the interaction with the gas diffusion hydrophobic substrate. The intrinsic ORR catalytic activity of the ink material is also analyzed on a glassy carbon electrode by the rotating ring-disc electrode (RRDE) method and specific capacitance measurements. The discharge capacity on our zinc/air battery prototype correlates well with the intrinsic catalytic activity in the RRDE. However, only the activity in the RRDE does not actually assure the performance on the commercial cathode of the prototype, since other chemical compatibility issues play a role. Thus, we highlight the importance of catalyst testing, not only on the RRDE but also under realistic device conditions.
Open Access
Compact wideband groove gap waveguide bandpass filters manufactured with 3D printing and CNC milling techniques
(MDPI, 2023-07-07) Máximo-Gutierrez, Clara; Hinojosa, Juan; Abad, José; Urbina Yeregui, Antonio; Álvarez-Melcon, Alejandro; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Zientziak
This paper presents for the first time a compact wideband bandpass filter in groove gap waveguide (GGW) technology. The structure is obtained by including metallic pins along the central part of the GGW bottom plate according to an n-order Chebyshev stepped impedance synthesis method. The bandpass response is achieved by combining the high-pass characteristic of the GGW and the low-pass behavior of the metallic pins, which act as impedance inverters. This simple structure together with the rigorous design technique allows for a reduction in the manufacturing complexity for the realization of high-performance filters. These capabilities are verified by designing a fifth-order GGW Chebyshev bandpass filter with a bandwidth BW = 3.7 GHz and return loss RL = 20 dB in the frequency range of the WR-75 standard, and by implementing it using computer numerical control (CNC) machining and three-dimensional (3D) printing techniques. Three prototypes have been manufactured: one using a computer numerical control (CNC) milling machine and two others by means of a stereolithography-based 3D printer and a photopolymer resin. One of the two resin-based prototypes has been metallized from a silver vacuum thermal evaporation deposition technique, while for the other a spray coating system has been used. The three prototypes have shown a good agreement between the measured and simulated S-parameters, with insertion losses better than IL = 1.2 dB. Reduced size and high-performance frequency responses with respect to other GGW bandpass filters were obtained. These wideband GGW filter prototypes could have a great potential for future emerging satellite communications systems.
Open Access
Passive heating and cooling of photovoltaic greenhouses including thermochromic materials
(MDPI, 2021-01-15) Padilla, Javier; Toledo, Carlos; López-Vicente, Rodolfo; Montoya, Raquel; Navarro, José-Ramón; Abad, José; Urbina Yeregui, Antonio; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
The integration of photovoltaic technologies into greenhouse envelopes appears to be an innovative and environmentally-friendly way to supply their various energy demands. However, the effect on the inner growing conditions, especially on the temperature, must be assessed in order to effectively implement this solution. In this study, experimental temperature data were obtained over two years for four structures built with different photovoltaic technologies (mono-crystalline silicon, amorphous silicon, cadmium telluride, and an organic polymeric technology) and fitted to a thermal model in order to provide a comprehensive analysis of their potential utilization as a cover material in greenhouses. Additionally, the thermal effect of color in structures composed of several common construction materials (brick, wood, plasterboard and glass) was quantified and modelled, supplementing the thermal analysis of passive solutions for this application. In all cases, inner and ambient temperature differences of up to +20 °C, created by a passive heating effect during the day, and – 5 °C, created by a passive cooling effect during the night, have been observed, suggesting the use of the photovoltaic modules with different degrees of structure coverage, complemented with the color tuning of the modules themselves as passive methods to control the temperature and light spectrum of greenhouses.
Open Access
Short vs. long-distance avocado supply chains: life cycle assessment impact associated to transport and effect of fruit origin and supply conditions chain on primary and secondary metabolites
(MDPI, 2022-06-19) Pedreschi, Romina; Ponce, Excequel; Hernández, Ignacia; Fuentealba, Claudia; Urbina Yeregui, Antonio; González-Fernández, José J.; Hormaza, José I.; Campos, David; Chirinos, Rosana; Aguayo, Encarna; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
Avocado consumption and trade are increasing worldwide, with North America and Europe being the main importing regions. Spain is the major European avocado producer (90% of the production), yet it only supplies 10% of the market. Consequently, more than 90% of the avocados consumed in Europe are imported from overseas, mainly from Chile and Peru. In this work, the Life Cycle Assessment (LCA) impact associated with the transport of two avocado supply chains (short (Spanish) and long (Chilean)) and the effect of the fruit origin and distance of both chains on primary and secondary metabolites from harvest to edible ripeness were evaluated using a gas chromatography-mass spectrometry (GC-MS) and liquid chromatography coupled to diode array detection (LC-DAD) based metabolite analysis. The LCA transport impact of the fresh supply chain from production centers in Chile (Quillota) and Spain (Malaga), and then the distribution to several cities in Europe, suggested road export from Spain to European capitals to have the lowest impact (0.14 to 0.22 kg CO2 eq/kg of avocado). When export from Chile was considered, the option of oceanic freight to European ports closer to final destinations was clearly a better option (0.21 to 0.26 kg CO2 eq/kg) than via the Algeciras port in Spain followed by road transport to final destinations in European capitals (0.34 to 0.43 kg CO2 eq/kg), although the situation could be somewhat different if the avocados are transported from the destination ports in northern Europe to long-distance capitals in other European countries. Fruit origin had a significant impact on avocado primary and secondary metabolites. The conditions of the supply chain itself (10 d in cold storage in regular conditions vs. 30 d cold storage + controlled atmosphere conditions) largely influence the fate of some metabolites that certainly affect the pool of metabolites at edible ripeness. The long-assumed hypothesis that the longer the supply chain the more negative impact on nutritional and functional compounds might not hold in this case, as long as transport conditions are adequate in terms of temperature, atmosphere conditions, and time considering distance from origin to destination.
Open Access
Cubierta vegetal bajo las cepas: una alternativa al control de las malas hierbas en los viñedos
(INTIA (Tecnologías e Infraestructuras Agroalimentarias), 2023) Abad Zamora, Francisco Javier; Cibriain Sabalza, Félix; Sagüés Sarasa, Ana; Santesteban García, Gonzaga; Lezáun San Martín, Juan Antonio; Fabo Boneta, Jesús María; Virto Quecedo, Íñigo; Imbert Rodríguez, Bosco; Marín Arroyo, Remedios; Garbisu Crespo, Carlos; Ciencias; Zientziak; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD
En este artículo se presentan los resultados obtenidos con una cubierta vegetal de trébol sembrada bajo las cepas para competir con las malas hierbas, de manera que no sea necesario recurrir al empleo de herbicidas o laboreos intercepas.
Open Access
Fast calculation methods for the magnetic field of particle lattices
(AIP Publishing, 2025-02-14) Royo Silvestre, Isaac; Gandía Aguado, David; Beato López, Juan Jesús; Garayo Urabayen, Eneko; Gómez Polo, Cristina; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
With the rise of 3D printing and composite materials, components comprising dispersed magnetic particles have become more interesting due to the possibility to design magnetic elements of any shape with varying amounts of the actual magnetic material. However, quick and easy calculation methods are needed to design these components enabling the selection of the optimum required percentage of magnetic particles (millimeter parts contain billions of micro-sized particles). This work proposes a semi-analytical iterative method for the estimation of the magnetic field generated by magnetic composites formed by embedded magnetic particles. The model is compared in terms of accuracy and calculation speed with finite element analysis and the average magnetization model of the magnetic composite. The results are finally supported by the comparison with experimental measurements of the weak magnetic field generated by a magnetic particle lattice.
Open Access
How the pretreatment temperature of zeolitic catalysts can affect the reaction temperature of methanol to olefins and gasoline processes
(MDPI, 2025-03-20) Yunes, Simón; Rosas, Abel Gaspar; Gil Bravo, Antonio; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
The dehydration of methanol to produce light olefins and gasoline, known as MTO (methanol-to-olefins) process requires acidic catalysts that maintain their acidity at reaction temperatures. Zeolites, such as SAPOs and ZSM-5, are commonly used for this purpose due to their acidic centers. The initial step in these experiments involves the activation or pretreatment of these solids to remove physically adsorbed water from their pores. Inadequate pretreatment can lead to the destruction of the existing Brönsted sites through the dihydroxylation of surface -OH groups. Therefore, it is crucial to pretreat the zeolites properly to preserve the Brönsted sites. One method is to subject the fresh catalyst to programmed dehydration, which involves desorption at a controlled temperature while monitoring the appearance of water that results from Brönsted site dihydroxylation. The temperature at which the dehydration peak appears determines the optimal reaction temperature. The results presented in this work will demonstrate the progressive deactivation of the catalysts when the reaction temperature exceeds 400 °C.
Embargo
Realidad aumentada para abordar la interacción luz-materia
(Graó, 2025-01-01) Napal Fraile, María; Uriz Doray, Irantzu; Méndez García, Ainhoa; Zudaire Ripa, María Isabel; Ciencias; Zientziak; Institute for Advanced Social Research - ICOMMUNITAS
El artículo describe el uso de tecnología educativa para aprender sobre la interacción luz-materia en distintos niveles educativos. La primera propuesta se refiere a una exposición didáctica que combina animaciones y representaciones 3D que se superponen a los objetos reales mediante Realidad Aumentada, y que se mostró útil para facilitar la comprensión de conceptos abstractos, conectando experiencias visibles con modelos teóricos. En un segundo nivel, y buscando provocar una implicación más activa en la construcción del modelo, se presenta una propuesta con sensores, centrada en la relación entre luz absorbida y energía transmitida, percibida como aumento de temperatura
Open Access
Quest for amorphous superconductors of Bi-Sb alloys by irradiation with swift heavy ions
(AIP Publishing, 2025-03-17) Andrino-Gómez, Alberto; Tabares, Gema; Moratalla, Manuel ; Redondo-Cubero, Andrés; Madurga Pérez, Vicente; Favieres Ruiz, Cristina; Vergara Platero, José; García-López, Gastón; Gordillo, Nuria; Ramos, Miguel Ángel ; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
Crystalline Bi100−xSbx alloys are known as the first discovered topological insulators, as well as for their promising thermoelectric properties, while their amorphous counterparts exhibit superconductivity (Tc > 6 K). However, their strong tendency to crystallize has hindered both the study and practical applications of amorphous Bi and Bi–Sb alloys. To explore the possibility of obtaining amorphous superconducting phases and enhancing thermoelectric properties, we investigated ion-beam irradiation as a method to induce amorphization in Bi100−xSbx alloys. We report irradiation experiments on pure Bi and Bi100−xSbx using bismuth and iodine ions (tens of MeV), generating an estimated vacancy damage of 40%–80%. Structural characterization and electrical resistivity measurements (2–300 K) revealed that, while amorphization and superconductivity were not achieved, melt-spun samples exhibited an order of magnitude higher conductivity than thermally evaporated ones. Moreover, ion-induced disorder further improved electrical conductivity, particularly in Bi90Sb10, highlighting its potential for thermoelectric applications.
Open Access
Highly selective CO formation via CO2 hydrogenation over novel ceria-based high-entropy oxides (HEOs)
(Elsevier, 2025-03-01) Cortázar, María; Lafuente Adiego, Marta; Navarro Puyuelo, Andrea; García, Xènia; Llorca Piqué, Jordi; Reyero Zaragoza, Inés; Bimbela Serrano, Fernando; Gandía Pascual, Luis; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In the present study, new ceria-based high-entropy oxides (HEOs) were investigated as CO2 hydrogenation catalysts. The nominal composition was (Ce0.5Ni0.1Co0.1Cu0.1Zn0.1Mg0.1)Ox and the synthesis was accomplished through the citrate complexing sol-gel method. Characterization techniques utilized including ICP-AES, in situ XRD and in situ XPS, SEM-EDS, HR-TEM and HAADF-STEM, Raman spectroscopy, H2-TPR, CO2-TPD and N2 physical adsorption. The physicochemical characterization and the catalytic results revealed that the conditions of the thermal treatments at which the oxides were subjected critically determined the catalytic performance, especially the CO2 hydrogenation products selectivities. Calcination in air and/or reduction in hydrogen conducted at temperatures below 500 °C led to active but poorly selective catalysts that produced both methane and CO with significant yields. This was mainly attributed to the presence of metallic Cu, Ni and Co on the catalysts that appeared to be supported on ceria doped with the rest of the formulation elements. In contrast, thermal treatments at 750 °C favored the formation of a rocksalt entropy-stabilized (NiCoCuZnMg)Ox HEO supported on ceria that has stood out for showing an excellent selectivity towards the reverse water¿gas shift (RWGS) reaction. This catalyst led to CO selectivities of almost 100 % over a very wide range of reaction temperatures (300-700 °C). Long-term stability tests (100 h) showed only a slight decrease in CO2 conversion, while CO selectivity remained stable at nearly 100 % at 400 °C. XRD characterization of the used catalysts evidenced that, whereas the basic catalyst structure remained, some metallic copper exsolved during reduction and reaction period. These results are relevant and very promising, opening a door to the development of new catalysts for the valorization of CO2 through the RWGS reaction, thus expanding the low-temperature limit at which this process can be carried out selectively.
Embargo
Photodegradation of paracetamol on CaAlGa and ZnAlTi mixed metal oxides (MMO) synthesized via LDH from Al-saline slags
(Elsevier, 2025-03-27) Jiménez, Alejandro; Guerra, Miguel; Pascual, Dana; Trujillano, Raquel; Rives, Vicente; Vicente, Miguel Ángel; Gil Bravo, Antonio; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
Preparation of CaAlGa and ZnAlTi mixed metal oxides (MMO) synthesized via CaAlGa–hydrocalumites and ZnAl–hydrotalcite impregnated with TiO2 using saline slags as aluminum source, is reported for the first time. The solids obtained by calcination at 750 ºC are highly crystalline and the photocatalytically active crystalline phases Ca12Al14-xGaxO33, ZnO, ZnAl2O4 and Zn2TiO4 have been identified. The MMO were used for the catalytic degradation of paracetamol under UV irradiation, obtaining good results for the removal of this emerging pollutant, reaching a removal above 90 % for the sample containing 25 % Ga3 +, under the optimum photodegradation conditions ([Paracetamol]0 = 40 mg/L and catalyst dose = 1 g/L), showing better results than the commercial photocatalyst TiO2–P25 from Degussa and other more complex catalysts based on MMO. In addition, this photocatalyst was submitted to a cyclic process study, finding that it maintained its performance after at least two cycles.
Embargo
Modified rule of mixtures and Halpin-Tsai models applied to PCL/NiMnInCo 4D printed composites. Internal stresses study during the martensitic transformation.
(Elsevier, 2025-05-26) Lambri, Fernando Daniel; Bonifacich, Federico Guillermo; Lambri, Osvaldo Agustín; Weidenfeller, B.; Recarte Callado, Vicente; Sánchez-Alarcos Gómez, Vicente; Pérez de Landazábal Berganzo, José Ignacio; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
4D printing enables the manufacturing of complex smart components in a wide variety of shapes. In devices based on 4D printed composite materials, the interaction between the active microparticles and the printable polymer matrix plays a critical role for the optimal functionality. Key parameters in these materials are the elastic misfit coefficient, which monitors internal stresses, and elastic energy transfer, which determines the ability to transfer strain from the microparticles to the surrounding matrix. In this work, the temperature-dependent shear modulus of PCL/Ni45Mn36.7In13.3Co5 4D printed composites is analysed using the modified rule of mixture (ROM) and Halpin-Tsai (HT) models. The molecular flow caused by the polymer chain movement under oscillatory mechanical stress at relatively elevated temperatures is examined and discussed using these models. Additionally, the effect of an external direct magnetic field on the shear modulus is also analysed. Finally, the internal stresses in the composite materials resulting from the martensitic transformation in the active microparticles are studied through a modified mean-field model based on the Eshelby's inclusion theory.
Open Access
A novel Enterococcus-based nanofertilizer promotes seedling growth and vigor in wheat (Triticum aestivum L.)
(MDPI, 2024-10-14) Batool, Salma; Safdar, Maryam; Naseem, Saira; Sami, Abdul; Saleem, Rahman Shah Zaib; Larrainzar Rodríguez, Estíbaliz; Shahid, Izzah; Ciencias; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB
Excessive use of chemical fertilizers poses significant environmental and health concerns. Microbial-based biofertilizers are increasingly being promoted as safe alternatives. However, they have limitations such as gaining farmers¿ trust, the need for technical expertise, and the variable performance of microbes in the field. The development of nanobiofertilizers as agro-stimulants and agro-protective agents for climate-smart and sustainable agriculture could overcome these limitations. In the present study, auxin-producing Enterococcus sp. SR9, based on its plant growth-promoting traits, was selected for the microbe-assisted synthesis of silver nanoparticles (AgNPs). These microbial-nanoparticles SR9AgNPs were characterized using UV/Vis spectrophotometry, scanning electron microscopy, and a size analyzer. To test the efficacy of SR9AgNPs compared to treatment with the SR9 isolate alone, the germination rates of cucumber (Cucumis sativus), tomato (Solanum lycopersicum), and wheat (Triticum aestivum L.) seeds were analyzed. The data revealed that seeds simultaneously treated with SR9AgNPs and SR9 showed better germination rates than untreated control plants. In the case of vigor, wheat showed the most positive response to the nanoparticle treatment, with a higher vigor index than the other crops analyzed. The toxicity assessment of SR9AgNPs demonstrated no apparent toxicity at a concentration of 100 ppm, resulting in the highest germination and biomass gain in wheat seedlings. This work represents the first step in the characterization of microbial-assisted SR9AgNPs and encourages future studies to extend these conclusions to other relevant crops under field conditions.
Open Access
Bio-oil fractionation according to polarity and molecular size: characterization and application as antioxidants
(American Chemical Society, 2024-12-21) Fonts, Isabel; Lázaro, Cristina; Cornejo Ibergallartu, Alfonso; Sánchez, José Luis; Afailal, Zainab; Gil-Lalaguna, Noemí; Arauzo, Jesús María; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Gobierno de Navarra / Nafarroako Gobernua
Bio-oil obtained from biomass pyrolysis has great potential for several applications after being upgraded and refined. This study established a method for separating bio-oil into different fractions based on polarity and molecular size to extract phenolic and polyphenolic compounds with antioxidant properties. The fractions were analyzed using various spectroscopic and chromatographic techniques, such as GC/MS, FTIR, UV-vis, SEC, DOSY-NMR, 13C-NMR, and 31P-NMR. The antioxidant properties of these fractions were tested by examining their ability to improve the oxidative stability of biodiesel. The results strongly connected the bio-oil's chemical functionalities and antioxidant power. During solvent fractionation, dichloromethane could extract phenolic structures, which were subsequently size-fractionated. The subfractions with lower molecular weight (in the order of monomers and dimers) outperformed the antioxidant potential of the crude bio-oil. Heavier subfractions from dichloromethane extraction did not show good antioxidant abilities, which was related to the low hydroxy group content. After solvent extraction, phenolic oligomers remained in the water-insoluble/dichloromethane-insoluble fraction, which showed good antioxidant potential despite its low solubility in biodiesel.
Open Access
Sintered glass filter as a membrane impregnated with g-C3N4 and AuAg/g-C3N4 to degrade rhodamine B with application in decentralized areas
(Elsevier, 2024-10-19) Sabogal-Paz, Lyda Patricia; Souza Freitas, Bárbara Luíza; Hoffmann, Maria Teresa; Royo-Pareja, David; López de Luzuriaga Fernández, José Manuel; Monge Oroz, Miguel; Santamaría Arana, Leticia; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Zientziak
This work shows a novel approach utilizing graphitic carbon nitride (g-C3N4) deposited on a sintered glass filter as a membrane enhanced with gold-silver nanoparticles for the removal of emerging pollutants. g-C3N4 was synthesized directly onto the membrane surface with a simple vapor deposition method. Membranes with two different porosities, g-C3N4 and the noble-metal nanoparticles were put to the test by exploring their photocatalytic capacity to degrade rhodamine B dye (RhB). FT-IR, PL, SEM, EDX and DRS characterization techniques were performed to analyse the catalysts. RhB degradation was tested in static (i.e. petri dish) and dynamic conditions (i.e. photocatalytic membrane setup). Filtered volumes, turbidity effect and stability were tested in dynamic conditions for the membrane that had the greatest potential for full-scale use. The results confirm the efficient RhB degradation capacity of the catalysts, highlighting the potential of this proposed setup; however, the cost of technology for decentralized areas is still an impediment. These findings not only contribute to advancing the understanding of pollutant removal technologies, but also, offer practical insights into the future deployment of such systems on a larger scale.
Open Access
Spatial and temporal grey water footprints of agricultural pesticide use: improved pesticide use options to decrease water pollution in China
(Elsevier, 2024-11-26) Yi, Junjie; Gerbens-Leenes, Winnie; Martínez Aldaya, Maite; Ciencias; Zientziak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD
Pesticides cause environmental and health risks. This study estimates the spatial-temporal dynamics of water pollution by pesticides and strategies for improvement. It uses the grey water footprint (WF) to identify the most polluting crops, hotspots and periods of increased water pollution with China as the case study area. It also proposes a temporal grey WF dimension due to pesticide degradation. The study used agricultural information for the period 2011–2015 from farmer surveys. The results showed that grey WFs were three times larger in summer than in winter. Hotspots were the North China Plain and Northeast China. Maize with herbicide (acetochlor) and insecticide (cypermethrin) use contributed most. In winter, the grey WFs in Southern regions were dominated by fungicide mancozeb use for vegetables and fruits. The temporal analysis of the grey WF due to pesticide degradation shows that the maximum daily grey WF was 66 % smaller than values based on the traditional calculation method. Moreover, replacing the most polluting pesticides, mancozeb, cypermethrin and acetochlor, can contribute to 20∼90 % of grey WF reduction across regions and months. Agriculture and policymakers can use this information to reduce pesticide-related water pollution.