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- Experimental Investigation of Green Nanofluids: Assessment of Wettability, Viscosity and Thermal ConductivityPublication . Nobrega, Glauco; Cardoso, Beatriz D.; Barbosa, Filipe; Pinho, Diana; Abreu, Cristiano; Souza, Reinaldo Rodrigues de; Moita, Ana S.; Ribeiro, J.E.; Lima, Rui A.Metallic nanoparticles are a type of nanomaterial synthesized from metallic precursors. Due to their unique physiochemical, electrical, and optical properties, metallic nanoparticles are widely studied and applied in various areas such as medicine, electronics, and heat transfer systems. However, conventional synthesis methods to produce metallic nanoparticles face challenges such as instability and environmental concerns, prompting the exploration of greener synthesis methods. Green synthesis uses natural resources like plants and algae as reducing agents, offering a more environmentally friendly approach for the synthesis of metallic nanoparticles. These green-synthesized metallic nanoparticles can enhance heat transfer by becoming part of nanofluids (NFs), which are colloidal mixtures of NPs in a fluid base. NFs, employed for heat transfer. As a result, it is essential to characterize the NFs regarding wettability, viscosity, and thermal conductivity. The results of the spectrophotometer confirmed the green synthesis of NPs, and it was observed that the increase in NP concentration impacted the contact angle, improving the ability to wet. The thermal conductivity is also modified, with an improvement of 11.3% compared to distilled water, without a significant increase in fluid viscosity.
- Theory of Operation of a Safety Finger Coupling Applied in the Drive of a Screw Conveyor for Bulk Agricultural MaterialsPublication . Bulgakov, Volodymyr; Pascuzzi, Simone; Olt, Jüri; Almeida, Arlindo; Trokhaniak, Oleksandra; Nowak, Janusz; Ihnatiev, Yevhen; Kiernicki, Zbigniew; Paciolla, Francesco; Scarascia-Mugnozza, GiacomoThe aim of the study is to enhance the operational characteristics of a screw conveyor during overloading of its working mechanism by substantiating the rational parameters of the safety coupling. Theoretical calculations and their graphical dependencies were performed using the Delphi programming environment. To increase the magnitude of axial displacement of the driven half-coupling with the jammedworking element, while reducing dynamic loads during overloading, a design of a safety coupling has been developed. To determine the rational parameters of the safety coupling for the screw conveyor, the influence of dynamic loads on the operation of the safety coupling during overloading of the screw conveyor’s working mechanism has been analyzed. From the analysis of the graphs, it has been determined that an increase in the rotation frequency n leads to an increase in the torque of the system. With a change in rotation frequency from 50 rpm to 200 rpm, the torque Td increases by 64.8%, Tr rises by 65.2%, and Tm increases by 63.8%. It has also been determined that an increase in the mass m of moving links leads to an increase in loads on the drive. When the mass increases from 10 kg to 20 kg, the torque Td increases by 15.8%, Tr rises by 12.5%, and Tm increases by 17.3%.
- Purification of green hydrogen from natural gas grids using zeolite 13XPublication . Zafanelli, Lucas F.A.S.; Henrique, Adriano; Aly, Ezzeldin; Rodrigues, Alírio; Silva, José A.C.Green hydrogen (GH) is a hot topic in the shift to clean energy, holding a promise to meet global energy demand while contributing to climate action goals. Its transportation can be done into Natural Gas (NG) grids, being necessary a separation technology to provide pure GH and NG to the end user. Accordingly, in this work, a series of breakthrough experiments evaluated the performance of binder-free zeolite 13X as a potential adsorbent to purify GH blended into NG grids. Single and multicomponent experiments were performed at 195, 231, and 273 K and pressure up to 1800 kPa. Noteworthy, the material enables a thermodynamic-based separation of these components due to its strong interaction with CH4, resulting in selectivity values up to 17 at 195 K. The dual-site and standard Langmuir isotherm models fitted the adsorption equilibrium data, being the simulated multicomponent breakthrough curves suitably predicted by a homemade dynamic mathematical model.
- Investigation of contact stresses in engagement elements of screw conveyor safety clutchPublication . Bulgakov, Volodymyr; Trokhaniak, Oleksandra; Aboltins, Aivars; Rucins, Adolfs; Tkachenko, Mycola; Almeida, Arlindo; Kuvachov, VolodymyrIn the article there is presented the design of a safety clutch for a screw conveyor with time-separated modes of slipping and axial displacement of the screw for automatic restoration of the operating condition in the event of overload. A calculation has been made using contact stresses in the engagement elements of the safety device, the level of which is the determining indicator that affects the wear rate of the contact surfaces. Using the SolidWorks Premium software diagrams of the distribution of contact stresses during operation of the safety clutch were constructed, by the results of which it was established that the analytical dependencies, presented in the article, can be used in the engineering design of various standard sizes of this protective mechanism.
- Metagenomic characterization of soil bacterial communities in young chestnut orchards in northern PortugalPublication . Pereira, Ermelinda; Choupina, Altino; Patrício, Maria SameiroSoil microorganisms play a crucial role in biogeochemical cycles and are key drivers of soil productivity. However, the soil bacterial community associated with the European chestnut (Castanea sativa Mill.) remains poorly characterized. In this sense, this study aimed to characterize the soil bacterial community in young chestnut orchards in Northern Portugal and investigate its dynamics throughout the year. Soil samples were taken in three different periods of the year (spring, summer, and autumn) from two young chestnuts orchards located in Parada (41⁰38'12.53” N; 6⁰42'42.94” W) and Salgueiros (41⁰54'12.73” N; 7⁰01'40.95” W) with elevations of 740 and 1008 m, respectively. Soil DNA was extracted, and the 16S rRNA amplicons were sequenced using the Illumina MiSeq platform. Overall, the bacterial core of chestnut orchards predominantly consisted of four main phyla: Proteobacteria, Acidobacteriota, Actinobacteriota, and Chloroflexi, which were consistently present in both study sites and across all seasons. However, the phylum Chloroflexi, known for its metabolic and phenotypic diversity, exhibited the highest prominence at higher altitudes during autumn. Acidobacteriales and Acidobacteriaceae (Subgroup 1) of Acidobacteriota, as well as Rhizobiales, Sphingomonadaceae, Rickettsiale, and Micropespsaceae, Burkholderiales, and Xanthomonadales of Proteobacteria, as well as Thermoleophila and Acidimicrobia of Actinobacteriota were dominant across all seasons and in both study sites. This study provides valuable insights into the bacterial community associated with chestnut species and contributes to monitoring potential ecosystem changes resulting from climate change.
- Post-combustion CO2 capture using ion-exchanged binder-free NaY zeolitesPublication . Aly, Ezzeldin; Zafanelli, Lucas F.A.S.; Henrique, Adriano; Silva, José A.C.; Silva. Francisco A.; Rodrigues, AlírioIon-exchange was performed on bare commercial binder-free NaY zeolite with al-kali (K+) and alkaline earth (Ca2+) metal cations in the range 23, 58, and 95% exchange for K+, and 56 and 71% for Ca2+, to be used as candidates regarding CO2 post-combustion capture (PCC) by adsorption processes. Adsorption equilibrium isotherms of CO2 and N2 were meas-ured on all these cation-exchanged samples using a chromatographic technique between 308 and 348 K and pressures up to 350 kPa and modelled by the dual-site Langmuir isotherm. The CO2 adsorption capacity increases as Na+ is exchanged further by K+ and the reverse for the Ca2+ ex-change. The single- and binary-component breakthrough curves were numerically simulated and accurately predicted using the Aspen Adsorption package. This work discloses the importance of ion-exchange on binder-free beads of NaY zeolite to improve its performance in PCC related applications.
- Pest Detection in Olive Groves Using YOLOv7 and YOLOv8 ModelsPublication . Alves, Adília; Pereira, J.A.; Khanal, Salik; Morais, A. Jorge; Filipe, VitorModern agriculture faces important challenges for feeding a fast-growing planet’s population in a sustainable way. One of the most important challenges faced by agriculture is the increasing destruction caused by pests to important crops. It is very important to control and manage pests in order to reduce the losses they cause. However, pest detection and monitoring are very resources consuming tasks. The recent development of computer vision-based technology has made it possible to automatize pest detection efficiently. In Mediterranean olive groves, the olive fly (Bactrocera oleae Rossi) is considered the key-pest of the crop. This paper presents olive fly detection using the lightweight YOLO-based model for versions 7 and 8, respectively, YOLOv7-tiny and YOLOv8n. The proposed object detection models were trained, validated, and tested using two different image datasets collected in various locations of Portugal and Greece. The images are constituted by sticky yellow trap photos and by McPhail trap photos with olive fly exemplars. The performance of the models was evaluated using precision, recall, and mAP.95. The YOLOV7-tiny model best performance is 88.3% of precision, 85% of Recall, 90% of mAP.50, and 53% of mAP.95. The YOLOV8n model best performance is 85% of precision, 85% of Recall, 90% mAP.50, and 55% of mAP.50 YOLO8n model achieved worst results than YOLOv7-tiny for a dataset without negative images (images without olive fly exemplars). Aiming at installing an experimental prototype in the olive grove, the YOLOv8n model was implemented in a Ubuntu Server 23.04 Raspberry PI 3 microcomputer.
- Comparative growth and yield performance of sweet chestnut in high-forest and coppice systems in young plantationsPublication . Patrício, Maria Sameiro; Nunes, LuísWe compare growth and yield of sweet chestnut in coppice and high-forest systems up to 24 years of age in Northern Portugal. In the coppice, data from 4 permanent plots submitted to different management models for small (P1), medium (P2) and large (P4) diameters, including a plot without intervention (P3), were used. Management model in P4 (1 shoot at the end of rotation) is converging to a similar product as high-forest over time. Site index (SI) for the coppice is 15 m of dominant height (hdom) at 20 years. The same SI was used when selecting data from permanent plots in high-forest for the comparison. Individual-tree equations previously developed were used to obtain stem volumes. Biomass of stem was obtained from volume using wood density. Results show that coppice for similar ages and SI, produces more stem volume per hectare than high-forest in any situation up to 24 years. At this age, height of the mean tree (hg) and hdom are lesser in the high-forest than in the coppice’s management model with similar target (P4). In contrast, diameter of the mean tree (dg) and dominant diameter (ddom) are similar in both systems. Results also show that P4 in coppice system produced more 100 m3 ha-1 of stem volume than the high-forest at age 24. However, mean annual increment (MAI) in stem volume in high-forest is still increasing as opposed to the coppice. Thus, coppice system produces more biomass in young ages than high-forest (MAI in biomass: 9 t ha-1 year-1 against almost 4 t ha-1 year-1, respectively). Managing coppice for a final target similar to high-forest introduces flexibility in sylviculture, allowing both high amount of biomass production in young stages, and long-life products at the end of rotation.
- Thermal analysis for testing underground battery locationPublication . Gonçalves, E.S.; Gonçalves, J.; Rosse, Higor Vendramini; Costa, José Joaquim; Jorge, Luísa; Gonçalves, José; Coelho, João Paulo; Ribeiro, J.E.The energy storage batteries, employed in solar systems installed on lampposts, are usually placed in devices such as switchboards fixed at an elevation near the top of the column. However, this storage solution becomes inefficient, because it is not possible to guarantee the control of the working temperature of the batteries, due to the low thermal insulation capacity of these storage devices. In this sense, an underground compartment made of concrete, steel plate and rock wool were created, embedded in the foundation of the lamppost, with the purpose of using geothermal energy to maintain an adequate temperature inside the compartment. To verify the temperature inside the battery storage compartment, a thermal analysis was performed, where heat transfer by conduction, convection and radiation was considered. Analyses were performed in steady state, and later, transient state, considering the initial temperatures of the thermal study in the previous steady state. With a storage volume of 1m3 and the base of the compartment at a depth of 2m, it was verified that it is possible to use geothermal energy to cool or heat, depending on the season, a system through geothermal energy. Considering a typical day in July, with room temperature of 35oC, a reduction of approximately 8oC was obtained inside the storage compartment, compared to the ambient temperature.
- Useful Project Management Practices in Collaborative R&D&I ProjectsPublication . Fernandes, Gabriela; Tassari, Guilherme; Rocha, Lucas; Ferreira, Luís Miguel D.F.; Santos, José M.R.C.A.; Ribeiro, Pedro; Barroso, Daniela; Pinto, Eduardo B.Collaborative Research and Development and Innovation (R&D&I) projects make an essential contribution to the development of knowledge-based, innovative products, processes, and services. The main objective of this paper is to gain a comprehensive understanding of project management (PM) in collaborative R&D&I projects, examining the usefulness of PM practices. The results are based on 465 valid responses from an online questionnaire survey on the perceptions of collaborative R&D&I project practitioners. The Relative Importance Index was used to classify the usefulness of the 35 key PM practices surveyed. The top 10 rank of the most useful PM practices cover the entire PM lifecycle and include well-known practices, such as ‘kick-off meeting’, ‘progress meetings’, ‘Gantt chart’, ‘project closure report’, ‘project closure meeting’, ‘milestone list’, ‘requirement analysis’ and ‘project scope plan’. Although, there are also less emphasised PM practices such as ‘alignment workshops’ and ‘project idea paper’. The paper contributes to supporting practitioners to decide which PM practices should be prioritised and implemented.