Dpto. Ingeniería Agrícola y Forestal42https://uvadoc.uva.es/handle/10324/11662024-03-29T08:57:24Z2024-03-29T08:57:24ZLight energy efficiency in lettuce crop: Structural indoor designs simulationLozano Castellanos, Luisa FernandaNavas Gracia, Luis ManuelCorrea Guimaraes, Adrianahttps://uvadoc.uva.es/handle/10324/669452024-03-22T20:00:41Z2023-01-01T00:00:00ZIndoor agricultural offers efficient alternatives for intensive food production through automation technologies and controlled environments. Light plays a crucial role in plant development; however, photons captured by the crop are often wasted in empty spaces, resulting in low light efficiency and high energy costs. This research aims to simulate eight structural designs for an indoor lettuce crop, exploring different planting systems and light and culture bed combinations (static and mobile) to identify the most effective mechanism for light efficiency during crop growth. The simulations were carried out with spreadsheets based on applying formulas of yield in dry biomass per photosynthetic photons, lighting costs, harvest, and production. The results indicate that Circular Moving Light and Mobile Culture Bed with Quincunx Planting (CML-QM) and Circular Moving Light and Mobile Culture Bed with Linear Planting (CML-LPM) exhibit higher photon capture percentages (85% and 80%, respectively) and lower electricity consumption compared to static designs. The simulation results demonstrate the potential for significant improvements in photon capture and cost savings through optimized system designs. This investigation provides valuable insights for designing more efficient systems and reducing electricity consumption to enhance the capture of photosynthetic photons in indoor lettuce cultivation.
2023-01-01T00:00:00ZUncaria tomentosa-loaded chitosan oligomers–hydroxyapatite–carbon nitride nanocarriers for postharvest fruit protectionSantiago Aliste, AlbertoSánchez Hernández, EvaBuzón Durán, LauraMarcos Robles, José LuisMartín Gil, JesúsMartín Ramos, Pablohttps://uvadoc.uva.es/handle/10324/666192024-03-13T20:00:35Z2023-01-01T00:00:00ZGiven the risks associated with synthetic fungicides, it is crucial to explore safe and sustainable alternatives. One potential solution is using bioactive natural products (BNPs). However, BNPs face challenges like lability, solubility, and lack of specificity. These issues can be addressed through nanoencapsulation. This study focuses on the evaluation of novel chitosan oligomers–hydroxyapatite–carbon nitride (COS–HAp–g-C3N4) nanocarriers (NCs) for encapsulating BNPs, specifically an extract from Uncaria tomentosa bark. The NCs were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and infrared spectroscopy. The NCs were monodisperse, with a mean diameter of 250 nm, and showed an encapsulation efficiency of 82%. The suitability of the loaded NCs (COS–HAp–g-C3N4–BNP, in a 2:1:0.5:1 weight ratio) for postharvest fruit protection was investigated in vitro and ex situ at a laboratory scale. Results regarding their efficacy against Botrytis cinerea on strawberries, Colletotrichum gloeosporioides on mangoes, Penicillium expansum on apples, Monilinia laxa on peaches, and Sclerotinia sclerotiorum on kiwifruit are presented. Minimum inhibitory concentrations of 250, 375, 375, 250, and 187.5 μg·mL−1 were found in vitro, respectively, while higher doses (500, 750, 750, 250, and 375 μg·mL−1, respectively) were needed to achieve effective control in postharvest tests on artificially inoculated fruit. These findings suggest that NCs containing extracts from U. tomentosa bark show promise as biorational agents and as alternatives to conventional fungicides for managing postharvest phytopathogens.
2023-01-01T00:00:00ZGel rheological properties and storage texture kinetics of starches isolated from anchote (Coccinia abyssinica (Lam.) Cogn.) cultivarsWolde, Yohannes TolesaEmire, Shimelis AdmassuAbebe Zeleke, WorkinehRonda Balbás, María Felicidadhttps://uvadoc.uva.es/handle/10324/665902024-03-11T20:01:26Z2023-01-01T00:00:00ZAnchote is a tuber crop indigenous to Ethiopia. Starch hydration properties and important gel characteristics which include: color, gel rheological properties (at 2, 4, 6, 8, and 10% starch:water w/w) and gel texture evolution (at 10% starch:water w/w), during 0 to 192 h storage (at 4 °C), of anchote starches isolated from four anchote cultivars (Desta 01, Desta 24, white and red) were evaluated and compared with potato and cassava starches (PS and CS). The lightness (L*) and whiteness scores of the anchote starch ranged up to >95, with slight differences among the cultivars, making them pure starches. Swelling power (SP) and water solubility index (WSI) of the anchote starches increased with increasing cooking temperature (40, 50, 60, 70, 80 and 90 °C), and their rate of increase varied significantly with the control starches, as follows: CS < anchote starches < PS. Anchote starch gels resisted higher stresses before breaking their structure and showed higher elasticity with lower (tan δ)1 values than PS and CS gels. They also had greater viscoelastic moduli even at lower concentrations than the PS and CS gels, and their stability increased with increasing concentration. The study of the gels’ texture evolution during storage revealed that anchote starch gels had significantly higher (≥40%) initial and final (after 192 h) hardness and were less adhesive than the PS gel. Despite some significant differences in the studied starch gel quality parameters among the starches from the anchote cultivars, the results suggested their promising potential as additional new materials in the development of food products, specifically as a functional ingredient for the formulation of gel-like products.
2023-01-01T00:00:00ZValorisation of buckwheat by-product as a health-promoting ingredient rich in fibre for the formulation of gluten-free breadGutiérrez, Ángel L.Villanueva Barrero, MarinaRico Bargués, DanielHarasym, JoannaRonda Balbás, María FelicidadMartín Diana, Ana BelénCaballero Calvo, Pedro Antoniohttps://uvadoc.uva.es/handle/10324/665572024-03-07T20:00:46Z2023-01-01T00:00:00ZBread is a widely consumed food that has often been used as a vehicle for functional ingredients such as dietary fibre. Fibre-rich breads have beneficial physiological effects on health, helping to combat chronic pathologies such as cardiovascular disease, diabetes, and certain types of colon cancer. The aim of this study is to evaluate the technological and nutritional effects of the inclusion of buckwheat hull particles (BH) at two addition levels (3 and 6%) and two particle sizes (fine, D50: 62.7 μm; coarse, D50: 307 μm) in a gluten-free (GF) bread formulation. A significant (p < 0.05) increase in the dough elastic modulus (G’) was observed for all doughs containing BH, from 712 Pa for a rice-based dough to 1027–3738 Pa for those containing BH. Compared to rice-based breads, those containing BH showed a significant (p < 0.05) increase in total dietary fibre content (from three to five times) and in antioxidant capacity (from 78 to 290 mg TE/100 g dw. in the ORAC test). Breads containing fine BH at a level of 3% had similar sensory properties to the rice-based bread, demonstrating that it is possible to improve the TDF content while maintaining the sensory quality of the GF bread.
2023-01-01T00:00:00ZPassive Electroluminescence and Photoluminescence Imaging Acquisition of Photovoltaic ModulesRedondo-Plaza, AlbertoMorales-Aragones, José IgnacioGallardo-Saavedra, SaraMateo-Romero, Héctor FelipeAraujo-Redón, SantiagoZorita-Lamadrid, Ángel L.Alonso-Gómez, VíctorHernández-Callejo, Luishttps://uvadoc.uva.es/handle/10324/664202024-02-28T20:00:36Z2024-02-28T00:00:00ZIn photovoltaic power plant inspections, techniques for module assessment play a crucial role as they enhance fault detection and module characterization. One valuable technique is luminescence. The present paper introduces a novel technique termed passive luminescence. It enhances both electroluminescence and photoluminescence imaging acquisition in photovoltaic power plants under normal operation in high irradiance conditions. This technique is based on the development of an electronic board, which allows the polarity of the module to be changed, enabling the current generated by the photovoltaic string to be injected into the module and producing electroluminescence effects. Additionally, the board can bypass the module and set an open circuit, inducing photoluminescence emission using sunlight as an excitation source. The proper coordination of the board and an InGaAs camera with a bandpass filter has allowed for the integration of a lock-in technique, which has produced electroluminescence and photoluminescence pictures that can be used for fault detection.
2024-02-28T00:00:00ZNutritional and physical characterization of sugar-snap cookies: effect of banana starch in native and molten statesRoman, LauraSahagun, MartaGomez, ManuelMartinez, Mario M.https://uvadoc.uva.es/handle/10324/661312024-02-12T20:01:23Z2019-01-01T00:00:00ZStarch is the major glycemic carbohydrate related to postprandial glycaemia and it naturally exists in the form of partially crystalline starch granules. Interestingly, the microstructural and granular features of banana starch have been reported to be inherently resistant to enzyme digestion. Converse to bread, sugar-snap cookie dough undergoes minimum starch gelatinization during baking. Therefore, the inclusion of banana starch in sugar-snap cookies could have a major role on starch susceptibility to be undigested or digested slowly, which could be especially relevant in gluten-free diets, typically characterized by a lower fiber intake and higher glycemic index. Here, we demonstrate that the starch digestion rate (k) and consumer’s acceptance of gluten-free sugar- snap cookies can be simultaneously improved by a 30 % replacement of rice flour by native banana starch. Furthermore, the content of resistant starch was increased from 0.1 to 3.6 % (g /100 g cookie), which would allow labeling of cookies as “source of fiber” in some food regulations. We also showed that the inclusion of fully gelatinized banana starch causes an increase of the water fraction that dramatically shifts the texture from brittle to soggy, according to the three- point bending test, that contributed to worsen consumer’s acceptance. Classic sugar-snap cookies are composed mainly of a continuous glassy sucrose-water matrix which confers this product its brittle textural properties. Therefore, when selecting novel starches for low/sustained glycemic response, it is paramount to deliberately formulate sugar-snap cookies to begin their shelf-lives in a glassy state that allows a desired crispy texture.
2019-01-01T00:00:00ZOpen Source Monitoring and Alarm System for Smart Microgrids Operation and Maintenance ManagementIzquierdo-Monge, OscarRedondo-Plaza, AlbertoPeña-Carro, PaulaZorita Lamadrid, Ángel LuisAlonso-Gómez, VíctorHernández Callejo, Luishttps://uvadoc.uva.es/handle/10324/661162024-02-12T20:01:21Z2023-01-01T00:00:00ZMicrogrids are becoming increasingly important for improving the dependability, stability, and quality of the electrical system, as well as for integrating renewable technologies. This paper describes a novel monitoring and alarm system that has been developed to optimize the operation and maintenance of microgrids. The system is unique in that it has been developed using open source software, including Node-RED, Home Assistant, Maria DB, and Telegram, and it allows for easy programming of alarms or warnings. Testing of the system has taken place within the CEDER microgrid and is capable of detecting faults in various components of the microgrid, such as generation units, storage systems, and loads. Upon detecting a fault, the system immediately sends a text message to the mobile phones of the microgrid operator or maintenance crew, enabling them to promptly address the problem. The software can also manage preventive maintenance of the microgrid by sending periodic reminders to the maintenance crew regarding necessary tasks.
2023-01-01T00:00:00ZA Power-Line Communication System Governed by Loop Resonance for Photovoltaic Plant MonitoringMorales-Aragones, José IgnacioWilliams, Matthew St. MichaelKupolati, HalleluyahAlonso-Gómez, VíctorGallardo-Saavedra, SaraRedondo-Plaza, AlbertoMuñoz-García, Miguel ÁngelSánchez-Pacheco, Francisco JoséHernández-Callejo, Luishttps://uvadoc.uva.es/handle/10324/661152024-02-12T20:01:20Z2022-01-01T00:00:00ZWithin this paper, a PLC system that takes advantage of the loop resonance of an entire DC-PV string configured as a circular signal path is developed and implemented. Low cost and extremely simple transceivers intended to be installed within each PV module of a string have been designed and successfully tested. In addition, an anti-saturation coil has been conceived to avoid saturation of the core when the entire DC current of the string flows through it. Bi-directional half-duplex communication was successfully executed with up to a 1 MHz carrier frequency (150 kbps bitrate), using a simple ASK modulation scheme. The transmission and reception performance are presented, along with the overall system cost in comparison to the previous literature.
2022-01-01T00:00:00ZA Resonant Ring Topology Approach to Power Line Communication Systems within Photovoltaic PlantsMorales-Aragonés, José IgnacioWilliams, Matthew St. MichaelGómez, Víctor AlonsoGallardo-Saavedra, SaraRedondo-Plaza, AlbertoFernández-Martínez, DiegoSánchez-Pacheco, Francisco JoséCuadro, Juan Gabriel FajardoHernández-Callejo, Luishttps://uvadoc.uva.es/handle/10324/659882024-02-08T20:01:54Z2022-01-01T00:00:00ZWithin this study, single-cable propagation facilitated by PV strings’ wiring characteristics is considered for an adapted design of PLC electronics. We propose to close the communications signal path, resulting in a ring topology where a resonance condition could be implemented. A PLC topology using the resulting circular closed-loop path of a PV series string as its physical communication support is designed and leveraged for practical use. When the path length or the number of transceivers is changed, the resonance properties that come with the circular path as the physical support are affected but are shown to be preserved with the application of automatic adjustable tuning. This automatic tuning guarantees that the resonance improves propagation parameters and reverts the system to its optimal values at the chosen carrier frequency.
2022-01-01T00:00:00ZOnline Distributed Measurement of Dark I-V Curves in Photovoltaic PlantsMorales-Aragonés, José IgnacioAlonso-García, María del CarmenGallardo-Saavedra, SaraAlonso-Gómez, VíctorBalenzategui, José LorenzoRedondo-Plaza, AlbertoHernández-Callejo, Luishttps://uvadoc.uva.es/handle/10324/659872024-02-08T20:01:52Z2021-01-01T00:00:00ZThe inspection techniques for defects in photovoltaic modules are diverse. Among them, the inspection with measurements using current–voltage (I-V) curves is one of the most outstanding. I-V curves, which can be carried under illumination or in dark conditions, are widely used to detect certain defects in photovoltaic modules. In a traditional way, these measurements are carried out by disconnecting the photovoltaic module from the string inside the photovoltaic plant. In this work, the researchers propose a methodology to perform online dark I-V curves of modules in photovoltaic plants without the need of disconnecting them from the string. For this, a combination of electronic boards in the photovoltaic modules and a bidirectional inverter are employed. The results are highly promising, and this methodology could be widely used in upcoming photovoltaic plants.
2021-01-01T00:00:00ZEnergy and economic analysis of renewable energy-based isolated microgrids with AGM and lithium battery energy storage: Case study Bigene, Guinea-BissauAguilar Jiménez, Jesús ArmandoHernández Callejo, LuisSuástegui Macías, José AlejandroAlonso Gómez, VíctorGarcía Álvaro, AlfonsoMaján Navalón, RaúlObregón, Lilian Johannahttps://uvadoc.uva.es/handle/10324/659042024-02-07T20:01:56Z2023-01-01T00:00:00ZBy the year 2020, 90% of the population with access to electricity worldwide was surpassed. However, the reality is very different for many countries, especially for those on the African continent that had more than 572 million people without electricity service at the end of 2019. This work studies the implementation of an isolated microgrid activated with photovoltaic energy and energy storage in batteries under the case study of the community of Bigene, located in the African country of Guinea-Bissau. This type of project is a potential solution to the problem of access to energy, but as the cost of the energy storage system is typically very high, this work technically and economically addresses the effect of using absorbed glass material (AGM) and lithium batteries. A simulator was developed using TRNSYS software to analyze the operation of the microgrid under a defined annual demand profile for different types of users, and economic analysis was conducted considering a project lifetime of 25 years. The results showed no significant differences in the solar fraction of both types of batteries when the photovoltaic power was less than 600 kW, regardless of the capacity of the storage bank. The analysis of auxiliary power requirements showed that lithium technology leads to a lower consumption from 800 kW of PV capacity, and utilizing less than this capacity did not have a significant difference with AGM batteries. In this microgrid with a photovoltaic capacity of less than 700 kW and an energy storage of less than 2580 kWh, the type of storage technology, AGM or lithium, did not represent a considerable difference in the levelized cost of energy, indicating that AGM technology could be selected considering its low initial investment cost compared to lithium batteries.
2023-01-01T00:00:00ZChemical constituents and antimicrobial activity of a Ganoderma lucidum (Curtis.) P. Karst. Aqueous ammonia extractSánchez Hernández, EvaTeixeira, AnaPereira, CatarinaCruz, AdrianaMartín Gil, JesúsOliveira, RuiMartín Ramos, Pablohttps://uvadoc.uva.es/handle/10324/658922024-02-07T20:01:55Z2023-01-01T00:00:00ZMushroom extracts have shown potential as a source of new antimicrobial agents. This study investigates the chemical profile of an aqueous ammonia extract obtained from the carpophores of Ganoderma lucidum, which grows on Quercus ilex trees, and explores its valorization as a biorational. The major chemical constituents of the extract, identified through gas chromatography–mass spectrometry, include acetamide, oleic acid, 1,2,3,4-butanetetrol, monomethyl azelate, undecane, and palmitic acid. The anti-oomycete and antifungal activity of G. lucidum extract was evaluated against Phytophthora cinnamomi, the primary threat to Quercus spp. in the dehesa biome, as well as three Botryosphaeriaceae fungi. In vitro tests revealed minimum inhibitory concentration (MIC) values of 187.5 μg·mL−1 against P. cinnamomi and 187.5–1000 μg·mL−1 against the fungi. Furthermore, conjugation of the G. lucidum extract with chitosan oligomers (COS) synergistically enhanced its antimicrobial activity, resulting in MIC values of 78.12 and 375–500 μg·mL−1 against P. cinnamomi and the fungi, respectively. These MIC values are among the highest reported to date for natural products against these phytopathogens. Subsequent ex situ testing of the COS-G. lucidum conjugate complex on artificially inoculated Q. ilex excised stems resulted in high protection against P. cinnamomi at a dose of 782 µg·mL−1. These findings support the potential utilization of this resource from the dehesa ecosystem to protect the holm oak, aligning with sustainable and circular economy approaches.
2023-01-01T00:00:00ZPartial photoluminescence imaging for inspection of photovoltaic cells: Artificial LED excitation and sunlight excitationRedondo Plaza, AlbertoNgungu, Victor NdetiGallardo Saavedra, SaraMorales Aragonés, José IgnacioAlonso Gómez, VíctorObregón, Lilian JohannaHernández Callejo, Luishttps://uvadoc.uva.es/handle/10324/658402024-02-06T20:02:15Z2023-01-01T00:00:00ZPhotovoltaic power is a crucial renewable energy source that has the potential to enhance a city’s sustainability. However, in order to identify the various issues that may occur during the lifespan of a photovoltaic module, solar module inspection techniques are crucial. One valuable technique that is commonly used is luminescence, which captures silicon emissions. This article focuses on a specific luminescence technique called partial photoluminescence. This technique involves illuminating a specific portion of the solar cell surface and recording the luminescence emission generated in the remaining area. This method has been trialed in a laboratory environment, utilizing infrared LEDs as the excitation source. An analysis of the main parameters that affect the technique is provided, where pictures have been taken under varying exposure times ranging from 50 ms to 400 ms, irradiance levels ranging from 200 W/m2 to 1000 W/m2, and a percentage of illuminated cells ranging from 10% to 40%. Furthermore, the experimental device has been modified to generate images utilizing sunlight as the excitation source. Several pictures of damaged cells were taken under an irradiance range of 340 W/m2 to 470 W/m2. The quality of the partial photoluminescence images is comparable to conventional electroluminescence images, but longer exposure times are required.
2023-01-01T00:00:00ZThe Use of Goats Grazing to Restore Pastures Invaded by Shrubs and Avoid Desertification: A Preliminary Case Study in the Spanish Cantabrian MountainsÁlvarez‐Martínez, JavierGómez‐Villar, AmeliaLasanta, Teodorohttps://uvadoc.uva.es/handle/10324/657832024-02-06T20:02:14Z2013-06-15T00:00:00ZSpanish mountains have been affected by the expansion of shrubs and forests since the mid-20th century. This secondary succession in vegetation has some positive effects, but also drawbacks, such as an increase in fire risk, loss of diversity in land use, a reduction in landscape and cultural value, less water available in river channels and reservoirs, constraints on livestock farming, a reduced number of local species and loss of biodiversity. This paper analyses the potential for grazing domestic goats to help control the spread of several species of shrubs such as the common broom (Cytisus scoparius), red raspberry (Rubus idaeus) and roses (Rosa sp.) that are commonly found in degraded pastures in the Cantabrian Mountains of northern Spain. Using experimental plots, the effects of two levels of stocking density (4·5 and 9 goats ha−1 y−1) are compared with other land management systems used in the region: burning, mechanical clearing and trimming. The combined use of goats with support from burning, clearing and trimming controls the spread of shrubs. The most efficient treatment was found with nine goats ha−1 y−1. Goat grazing also changes the distribution of shrubs, transforming a dense and continuous coverage into separate clumps and thereby enabling livestock to graze more easily. Maintaining a mixed structure of shrubs and pastures is the best treatment due to the low population density of the Cantabrian Mountains, as this enhances the biodiversity, controls fire risk and enriches the landscape; it also allows extensive livestock grazing as a main economic resource.
2013-06-15T00:00:00ZGlacial stages in the Peña Negra valley, Iberian Range, northern Iberian Peninsula: Assessing the importance of the glacial record in small cirques in a marginal mountain areaGarcía-Ruiz, José M.Palacios, DavidFernández-Fernández, José M.Andrés, NuriaArnáez, JoséGómez-Villar, AmeliaSantos-González, JavierÁlvarez-Martínez, JavierLana-Renault, NoemíLéanni, Laëtitiahttps://uvadoc.uva.es/handle/10324/657782024-02-06T20:02:12Z2020-08-01T00:00:00ZThe objective of this study was to assess whether it is possible to obtain a comprehensive record of the last deglaciation from the small Peña Negra glacial cirque in a marginal mountain range in the Iberian Range (northern Iberian Peninsula). The cirque is located in Sierra Cebollera, at an elevation slightly over 2000 m a.s.l. in the divide, and has relatively low elevational difference between its uppermost and lowest parts. The Peña Negra glacial cirque was selected because of the presence of several lateral moraines indicating the occurrence of a glacial tongue of 1.8 km length and a small rock glacier, enabling identification of the main glacial stages that affected the paleo-evolution of the glacier. Using cosmogenic exposure dating techniques and geomorphological mapping it was possible to reconstruct the historical Peña Negra glacier and to distinguish: (i) the maximum ice extent (MIE) at approximately 18–20 ka, coinciding with the Global Last Glacial Maximum (GLGM), although the occurrence of a previous stage was not ruled out; (ii) a stage of glacial re-advance at 16–17 ka, coinciding with the Oldest Dryas, followed by rapid ice melting; (iii) the development of a rock glacier in a minor structural cirque near the headwall at 14–15 ka, when paraglacial processes were probably dominant; and (iv) evidence of ice melting in the uppermost cirque at 13.5 ka. Study of the Peña Negra glacier revealed the history of a minor valley glacier affected by distinct stages, including the formation of a small rock glacier in the final phases of deglaciation. No evidence of a Younger Dryas re-advance was found.
2020-08-01T00:00:00Z‘Green’, rammed earth check dams: A proposal to restore gullies under low rainfall erosivity and runoff conditionsGalicia, S.Navarro-Hevia, J.Martínez-Rodríguez, A.Mongil-Manso, J.Santibáñez, J.https://uvadoc.uva.es/handle/10324/656602024-02-05T20:03:25Z2019-08-01T00:00:00ZGully restoration check dams are usually made with construction materials and have a permanent impact on the landscape. Although earthen dams have not been used to restore gullies, they have been used around the world for water reservoirs and to control flooding. Here, we propose ‘green’, rammed earth check dams as a better environmental solution to restore gullies and integrate check dams in the natural landscape. This new design of earthen dam aimed at achieving a reduction in construction volume, as we propose a straight profile for the earthen wall upstream and an impervious core made of rammed earth wall. Moreover, the sloping, revegetated profile downstream enables integrating the check dam into the landscape, while the rammed earth wall allows the use of traditional materials and construction methods better adapted to the natural environment. We also present the design process, calculating its stability versus overturning, sliding and ground resistance for its weight. In addition, we compare the construction costs and carbon footprint of the rammed earth check dam with those of other frequently used check dams, such as concrete or gabion check dams. It shows that although rammed earth check dams may have a greater cost (>21%), they also have a sink effect of 23,639.36 kg CO2 due to the vegetation cover on the downstream embankment. This work shows their feasibility in gullied areas and ravines of fine textured soils under low runoff and rainfall erosivity conditions.
2019-08-01T00:00:00Z