bluuebunny/crossref_metadata_2025 huggingface dataset:
Συμβολή στις πιθανοτικές προβλέψεις παραγωγής ΑΠΕ με χρήση προηγμένων τεχνικών μηχανικής μάθησης
Authors: Κωνσταντίνου Θεόδωρος
Published: October 2024

Η διδακτορική διατριβή επικεντρώνεται στην ανάπτυξη προηγμένων τεχνικών μηχανικής μάθησης για την πιθανοτική πρόβλεψη της παραγωγής ΑΠΕ, με έμφαση στην αιολική και ηλιακή ενέργεια. Η ενσωμάτωση των ΑΠΕ στα υφιστάμενα συστήματα ηλεκτρικής ενέργειας παρουσιάζει σημαντικές δυσκολίες για τους διαχειριστές συστημάτων και τους φορείς της αγοράς, κυρίως λόγω της εξάρτησής τους από τις καιρικές συνθήκες. Για την επιτυχή ενσωμάτωση των ΑΠΕ και τη μείωση των ανισορροπιών ισχύος στην αγορά, η ακριβής πρόβλεψη είναι απαραίτητη μαζί με την ανάπτυξη εργαλείων υποστήριξης αποφάσεων. Το πρώτο κεφάλαιο εισάγει το αντικείμενο της διατριβής και περιγράφονται οι στόχοι της έρευνας και το πλαίσιο μέσα στο οποίο αναπτύσσεται η διατριβή. Το δεύτερο κεφάλαιο επικεντρώνεται στην πρόγνωση καιρού και αναλύονται οι μέθοδοι πρόβλεψης καιρού και η σημασία τους για την ακριβή πρόβλεψη της ηλιακής και αιολικής ενέργειας. Το τρίτο κεφάλαιο παρουσιάζει τις τεχνικές φυσικής και στατιστικής μοντελοποίησης που χρησιμοποιούνται για την πρόβλεψη της παραγωγής από ΑΠΕ. Αναλύονται οι μέθοδοι πρόβλεψης και η σημασία τους για την ενσωμάτωση των ΑΠΕ στα υφιστάμενα συστήματα ηλεκτρικής ενέργειας. Στο τέταρτο κεφάλαιο εξετάζεται η επεξεργασία των αριθμητικών προβλέψεων καιρού για την πρόβλεψη της ταχύτητας του ανέμου. Παρουσιάζεται μια νέα μέθοδος βασισμένη στα τεχνητά νευρωνικά δίκτυα, η οποία προσεγγίζει τις συναρτήσεις των κατανομών πιθανοτήτων. Το πέμπτο κεφάλαιο παρουσιάζει τη χρήση υβριδικών νευρωνικών δικτύων για την εκτίμηση κατανομών πιθανότητας στην πρόβλεψη της παραγωγής ΑΠΕ. Αναλύεται η νέα παραμετρική μέθοδος που βασίζεται σε τεχνητά νευρωνικά δίκτυα, η οποία συνδυάζει τις διαδικασίες πρόβλεψης σε ομάδες και εκτίμησης πυκνότητας πιθανότητας σε μια ενιαία αρχιτεκτονική πολλαπλών συνιστωσών. Στο έκτο κεφάλαιο, αντιμετωπίζεται η πρόκληση της πρόβλεψης της παραγωγής ΑΠΕ από γεωγραφικά κατανεμημένες μονάδες σε μεγάλες περιοχές. Το πρόβλημα της διαστατικότητας που δημιουργείται από τον μεγάλο αριθμό δεδομένων εισόδου που βασίζονται στις προβλέψεις καιρού, επιλύεται με μια μέθοδο μείωσης της διαστατικότητας. Αυτή η μέθοδος χωρίζει τις αριθμητικές προβλέψεις καιρού σε υποπεριοχές και επιλέγει μόνο τις πιο σχετικές, οι οποίες χρησιμοποιούνται ως είσοδοι στα μοντέλα πρόβλεψης.Το έβδομο κεφάλαιο διερευνά την ακρίβεια, τη συνέπεια και την αξία των πιθανοτικών προβλέψεων παραγωγής ΑΠΕ. Αναλύονται οι βασικές αρχές των ενεργειακών αγορών. Η ανάλυση αυτή περιλαμβάνει τη χρήση πιθανοτικών μοντέλων για την πρόβλεψη της συνολικής παραγωγής και τη διαχείριση των κινδύνων που συνδέονται με τις διακυμάνσεις των τιμών και τη μεταβλητότητα της παραγωγής ενέργειας. Το τελευταίο κεφάλαιο συνοψίζει τα κύρια ευρήματα της διατριβής και προτείνει κατευθύνσεις για μελλοντική έρευνα. Αναλύονται οι κύριες συνεισφορές της διατριβής στην ανάπτυξη αξιόπιστων πιθανοτικών μοντέλων πρόβλεψης της ταχύτητας του ανέμου και της παραγωγής από ΑΠΕ, καθώς και οι προοπτικές για την περαιτέρω βελτίωση και εφαρμογή αυτών των μοντέλων σε πραγματικές συνθήκες.
Population dynamics of resident fish in a coastal lagoon under eutrophication-mediated habitat changes
Authors: GUERRERO-GÓMEZ ADRIÁN , ZAMORA-LÓPEZ ANTONIO , TORRALVA MAR , ZAMORA-MARÍN JOSÉ MANUEL , GUILLÉN-BELTRÁN ANTONIO , OLIVA-PATERNA J. FRANCISCO
Published: October 2024

Coastal lagoons, as transitional ecosystems, are crucial for providing ecosystem services and preserving fish communities, yet they face increasing pressures from anthropogenic activities. The Mar Menor coastal lagoon in the western Mediterranean exemplifies this challenge, as it suffers from severe eutrophication driven by agricultural and urban influences. In this study, we assess changes in the population dynamics of three resident fish species (Apricaphanius iberus, Pomatoschistus marmoratus, and Syngnathus abaster) in the context of human-induced impacts in the Mar Menor. Using long-term monitoring data (the reference period of 2002-2004 vs. the eutrophication period of 2015-2019), we analyze temporal variations in their population dynamics and their relationships with eutrophication-mediated structural changes in shallow waters. Our results suggest that these resident species, which are closely associated with shallow areas, show population dynamics that reflect habitat alterations, underscoring their potential as indicators of eutrophication impacts. This study enhances our understanding of the dynamics within transitional ecosystems and provides a basis for integrated management strategies aimed at promoting effective fish conservation.
Container buildings used for residential and business purposes in Johannesburg, South Africa and potential heat-related health risks
Authors: Mfamadi Tanganedzeni , Chivimbo Kimberley , Mogadime Philistase , Bidassey-Manilal Shalin , Kapwata Thandi , Naidoo Natasha , Wright Caradee Y
Published: October 2024

Background Outdoor and indoor air temperature affects human health and wellbeing. Climate change projections suggest that global temperatures will continue to increase, and this poses a threat to health. Buildings (for housing and business purposes) that can protect humans from the adverse effects of temperature are essential, especially in the context of climate change. Method In this cross-sectional study, we measured the indoor temperature inside shipping containers comprising a seven-storey block of apartments and businesses in Johannesburg, South Africa for 14 days. We assessed indoor temperature and relative humidity; evaluated measured temperatures in relation to thresholds known to be associated with adverse health risks; and sought to understand heat-health perceptions and symptoms of people living and working in shipping container units. Results Median indoor apparent temperature (AT) (a combination of temperature and relative humidity) was 16°C with values ranging from 6°C (observed at 8:00) to 42°C (observed at 17:00). Insulated units had temperatures between 2°C and 9°C cooler than the uninsulated unit. Heat-health risks from AT exposure were likely in all units, although there was variation in the number of occurrences that AT measurements exceeded the four symptom bands of caution, extreme caution, danger and extreme danger. Indoor AT was found to be 7°C higher on average when compared to outdoor AT. Some participants believed that their units were hot during hot weather and most people opened windows or did nothing during hot weather. Few participants reported experiencing adverse heat-health impacts, except for experiencing headaches (58%) and feeling tired or weak (40%). Conclusion Residents, tenants, or business owners using shipping containers should consider insulation installation and adequate windows/air conditioning for ventilation, especially in hot climates. Further research and awareness regarding heat-health risks of living or working in these spaces is needed.
Vitality structures in ‘addictive’ game design
Authors: Karhulahti Veli-Matti
Published: October 2024

For decades, research on technology use and mental health has been based on the assumption that identifiable structures of ‘design’ are psychologically relevant for their users. This has been central especially for the nosological emergence of ‘behavioural addictions’, which currently include two formal diagnoses on technology use: problems related to playing gambling games (gambling disorder) and videogames (gaming disorder). Alas, the research on identifying ‘addictive’ design structures has suffered from major construct validity issues. To make progress over those issues, I draw from the history of ‘vitality affects’ in psychiatry and introduce vitality structures as a design-phenomenological framework that can help researchers conceptualise psychologically relevant ‘bonds’ between entities of game design and corresponding player phenomenology. Vitality structures are not natural kinds to be discovered but pragmatic constructs to be used—and useful as long as they communicate what is both identifiable and empirically prevalent. As a demonstration of practice, I propose working conceptualisations of three vitality structures, which surface in videogames played by gaming treatment-seekers. Systematic research programs for identifying relevant vitality structures can lead to construct-valid and replicable design effects.
El escultor del rey en los siglos XVI y XVII: revisión y nuevas aportaciones para el conocimiento de una dignidad artística.
Authors: Díaz Gómez José Antonio
Published: October 2024

Este trabajo pretende profundizar en las particularidades que rodearon a los artistas que alcanzaron el puesto de Escultor de la Real Cámara o del rey entre 1552 y 1701. El punto de partida lo supondrán los trabajos que el profesor Martín González publicó en los años 90 aunque, si bien sus intereses se ocuparon fundamentalmente de las obras promocionadas por la Corona en este periodo, las páginas de este artículo se centrarán en los condicionantes que este título comportó para la forma de vida y el desarrollo profesional de los artistas que lo ostentaron. Este cambio de perspectiva, conllevará el descubrimiento de nuevos aspectos sobre el prestigio y los riesgos que suponía para estos autores trabajar para la Corte.
Apuntes sobre algunas novedades y precisiones en la obra de Vicente Carducho y Eugenio Cajés.
Authors: Pascual Chenel Alvaro
Published: October 2024

Se presentan y estudian en este artículo algunas novedades e incorporaciones en la obra de Vicente Carducho y Eugenio Cajés, dos de los artistas cortesanos más importantes del primer tercio del siglo XVII. Especialmente referidas a dibujos, pero también algunas precisiones documentales y sobre pinturas que incrementan nuestro conocimiento de sus métodos de trabajo, así como el corpus de obras conocidas.
Iconografía musical en los lienzos del Pregón de la Máscara de Domingo Martínez.
Authors: Mondéjar Muñoz Laura , Palacios Sanz José Ignacio
Published: October 2024

La iconografía musical aglutina detalles que permiten interpretar datos de diversa naturaleza vinculados con la obra artística. La serie de los carros sobre el Pregón de la Máscara, elaborada por Domingo Martínez entre 1748 y 1949, supuso el reflejo –en ojos del pintor sevillano– de una fiesta desde distintos puntos de vista, pero en la que música adquiere gran importancia, dada la elevada presencia de instrumentos y músicos. Este trabajo propone el análisis e interpretación de la iconografía musical de estos lienzos mediante conceptos que complementan la forma del instrumento representado, al mismo tiempo que pretende establecer conexiones entre la organología y la técnica interpretativa desde los convencionalismos y estandarizaciones habituales en el ecuador del siglo XVIII.
Y después de la desamortización… El templo de San Pedro de Alcántara de Sevilla a la luz de unos inventarios de 1836 y 1893.
Authors: Ruiz Barrera María Teresa
Published: October 2024

El propósito del artículo es dar a conocer dos inventarios sobre la iglesia del antiguo convento de san Pedro de Alcántara de Sevilla, de la orden franciscana descalza. Este hermoso templo del que apenas se conocen datos históricos sufrió, una y otra vez, las desamortizaciones del siglo XIX. Como resultado la merma del patrimonio artístico fue considerable. A este respecto los citados inventarios de 1836 y h. 1893, desvelan los bienes muebles que existían en esas fechas. En este estudio establecemos una comparación de sus datos en cuanto a la retablística, escultura y pintura que relacionamos con el actual patrimonio conservado, a la vez que se aportan las últimas noticias sobre la iglesia.
Influencia británica en Jerez de la Frontera. Un proyecto de villa victoriana de John Prichard (1864).
Authors: Serrano Macías Maribel
Published: October 2024

El presente trabajo de investigación se centra en el estudio de un novedoso proyecto de villa del arquitecto galés John Prichard en tierras gaditanas, dentro de las instalaciones de bodegas González Byass, en Jerez de la Frontera. La villa de la Quinta de la Alameda nunca llegó a construirse pero, de haberse hecho, habría sido la única de su clase en la ciudad. El diseño de Prichard sirvió de modelo para otros proyectos posteriores y fue pionero en el uso de recursos propios de la arquitectura inglesa, tan diferente de lo que hasta ahora se hacía en Jerez. Además, en este trabajo de investigación, se contextualiza el proyecto dentro de una época de fuerte influencia británica en la ciudad.
El pabellón del Reino de Murcia en la Exposición Iberoamericana de Sevilla.
Authors: Camacho Cárdenas Enrique , López Castillo José Miguel
Published: October 2024

El pabellón del Reino de Murcia en la Exposición Iberoamericana de Sevilla representó de manera conjunta a las provincias de Murcia y Albacete, ligadas históricamente. Las propuestas para el edificio, que sirvió de espacio expositivo, se centraron en mostrar un diseño arquitectónico que reuniera aspectos constructivos, decorativos y culturales propios del pasado histórico de la zona. En este trabajo se documenta la participación e historia del proyecto murciano-albacetense y se analizan los diseños realizados para el pabellón hasta la definitiva construcción del edificio.
Tracción animal y cultivo de cereales en el Alentejo a través del diálogo con la fotografía de Artur Pastor.
Authors: Pereira Cardeira Daniel Filipe
Published: October 2024

Los usos de la tracción animal fueron ampliamente documentados por el fotógrafo Artur Pastor, particularmente en el contexto agrícola y del cultivo de cereales. A través de una selección de fotografías de Pastor, pretendemos demostrar el diálogo entre su obra y los procesos de cultivo de cereales que utilizaban animales de trabajo en el Alentejo. Las imágenes presentadas coinciden con los métodos utilizados en la agricultura durante la época de las grandes arroteias, que se inició a finales del siglo XIX y se prolongó hasta el tercer cuarto del siglo XX. Utilizando la bibliografía de referencia sobre los métodos de producción de cereales en el Alentejo, pretendemos comprender el contexto de las obras de Pastor, darles significado y cuestionarlas
San Francisco de Asís bajo la mirada de José María Párraga: obra y dibujos preparatorios.
Authors: Sempere Marin Alicia
Published: October 2024

La vida y figura de San Francisco de Asís despertó un gran interés durante la segunda mitad del pasado siglo. En ese contexto se encargó al artista José María Párraga (1937-1997) la realización de todo un ciclo decorativo para la parroquia de San Francisco de Asís en la ciudad de Murcia. Párraga, cuya vasta producción incluye un amplio espectro de manifestaciones artísticas enmarcadas en un estilo personal e inclasificable, diseñó una serie de pirograbados, relieves y murales para la iglesia y su entorno, proyecto del que se conservan asimismo dibujos preparatorios.
Bacterial vaginosis: management in primary care settings
Authors: Perry Margaret
Published: October 2024

Margaret Perry looks at the diagnosis and treatment of this common women's health issue
Automatic Recognition of Agriculture Pests with Balanced Feature Pyramid Network
Authors: Chen Songnan , Yang Weiqiang , Chen Xuelin
Published: October 2024

HIGHLIGHTS

We propose a balanced feature pyramid network model to achieve automatic recognition of agricultural pests.

We propose and improved feature pyramid module to address the problems of the large semantic gap before feature fusion in FPN (feature pyramid network), information loss during feature fusion, and how to utilize complementary information to strengthen features after feature fusion.

Our method is evaluated on the pest dataset and achieves better recognition results, the mAP (mean Average Precision) reaches 90.04%, and the final mAP after combining with the data enhancement strategy reaches 92.56%.

Abstract.In order to ensure the steady improvement of the quality and efficiency of agricultural production, the precise prevention and control of agriculture pests should be given top priority. Based on the Faster R-CNN model, we propose a feature-augmented recognition model (FARM) for the detection of agricultural pests to improve the professional level of pest control. Firstly, we select VoVNet as the backbone network to extract rich visual information. Secondly, in view of the existing problems of FPN (Feature Pyramid Network), we propose a feature pyramid enhancement network to improve it. Finally, we use an adaptive anchor box network to train anchor boxes to avoid the problem of unbalanced positive and negative samples caused by artificial parameter adjustment. The experimental result shows that our method can achieve better recognition results; the mAP on the agricultural pest dataset reaches 90.04%, and the final mAP after combining with the data enhancement strategy reaches 92.56%. Keywords: Adaptive anchor box, Agricultural pests, Feature augmented, Feature pyramid.
A Novel Trichogramma ostriniae Release System to Control Ostrinia nubilalis in Sweet Corn
Authors: Dionne Ariane , Khelifi Mohamed
Published: October 2024

Highlights

A first novel injection system was built for spraying Trichogramma at a large scale in sweet corn fields.

A mechanical mixer was designed for a rapid dissolution of xanthan and guar gums.

The injection system achieved a Trichogramma emergence rate efficiency of 83%.

Hose drops addition resulted in an extra 44% spraying coverage underneath sweet corn leaves.

Abstract. In sweet corn processing sector, the use of Trichogramma for controlling Ostrinia nubilalis is uncommon in fields, primarily due to the absence of efficient mechanical deployment tools. The poor dissolution of xanthan and guar gums and the medium released along with Trichogramma also impedes the deployment of this biocontrol method. Thus, the preparation of the spraying solution and its application needed to be optimized to be feasible and profitable at a large scale. This work aimed to spray Trichogramma pupae by creating a novel tool: a specific mechanical mixer designed for the rapid dissolution of gums and a modular injection system containing a mixture of Trichogramma pupae and gum formulation to improve the Trichogramma spraying efficiency. Trichogramma emergence rate and concentration were assessed. Results showed that this spraying system greatly facilitated the release of Trichogramma ostriniae and the dissolution of xanthan and guar gums. Specifically, a 4-blade serrated dispersion disk dissolved 16 L at 12 g/L of gum in less than 6 minutes. The injection system successfully distributed pupae through both sides of the sprayer boom with an overall emergence rate efficacy of 83%. Also, an additional 44% of spraying coverage was achieved by spraying under sweet corn leaves using hose drops. Combined with the easy installation on any commercial sprayer, this modular injection system represents a promising pest control tool in organic and conventional crops. Keywords: Injection, Mechanized release, Ostrinia nubilalis, Spraying, Sweet corn, Trichogramma.
FishMOT: A Simple and Effective Method for Fish Tracking Based on IoU Matching
Authors: Liu Shuo , Zheng Xinyu , Han Lulu , Liu Xiaoyang , Ren Junli , Wang Fang , Liu Ying , Lin Yuanshan
Published: October 2024

Highlights

Existing tracking methods face challenges in accuracy and robustness.

FishMOT (Multiple Object Tracking for Fish) is a novel fish-tracking approach combining object detection and IoU matching.

FishMOT outperforms state-of-the-art multi-target trackers and specialized fish-tracking tools on several metrics.

The simplified workflow and strong performance make FishMOT a highly effective fish-tracking approach.

Abstract. Fish tracking plays a vital role in understanding fish behavior and ecology. However, existing tracking methods face challenges in accuracy and robustness due to morphological changes in fish, occlusion, and complex environments. This article proposes FishMOT (Multiple Object Tracking for Fish), a novel fish tracking approach combining object detection and IoU (Intersection over Union) matching, including a basic module, an interaction module, and a refind module. Wherein, a basic module performs target association based on the IoU of detection boxes between successive frames to deal with the morphological change of fish; an interaction module combines the IoU of detection boxes and the IoU of fish entities to handle occlusions; and a refind module uses spatio-temporal information to overcome the tracking failure resulting from the missed detection by the detector in a complex environment. FishMOT reduces the computational complexity and memory consumption since it does not require complex feature extraction or identity assignment per fish and does not need a Kalman filter to predict the detection boxes of successive frames. Experimental results demonstrate FishMOT outperforms state-of-the-art multi-object trackers and specialized fish tracking tools in terms of MOTA (Multiple Object Tracking Accuracy), accuracy, computation time, memory consumption, etc. Furthermore, the method exhibits excellent robustness and generalizability for varying environments and fish numbers. The simplified workflow and strong performance make FishMOT a highly effective fish-tracking approach. The source codes and pre-trained models are available at: https://github.com/gakkistar/FishMOT. Keywords: Behavior analysis, Fish behavior, Fish tracking, Multiple object tracking, Object detection.
Prediction of Solar Radiation using Deep LSTM-based Machine Learning Algorithm
Authors: K. C. Jayasankar  , G. Anandhakumar  , A. Kalaimurugan
Published: October 2024

Solar radiation, a critical parameter for various applications such as solar energy systems and weather forecasting, exhibits complex temporal patterns influenced by numerous environmental factors. In the quest to enhance the accuracy of solar radiation predictions, this study introduces a novel approach utilizing Deep Long Short-Term Memory (Deep LSTM) networks, a type of recurrent neural network (RNN) known for its capability to model sequential data. Traditional prediction methods often struggle to capture these intricacies, leading to sub-optimal performance. This investigation is based on a Deep LSTM-based machine learning algorithm designed to predict solar radiation with elevated exactitude. The model is meticulously trained on copious datasets encompassing historical meteorological data, including temperature, humidity, wind velocity, and antecedent solar radiation metrics. Pivotal stages encompass data preprocessing, judicious feature selection, and hyperparameter optimization to enhance the model’s predictive efficacy. Empirical results clearly illustrate that the Deep LSTM model surpasses traditional methodologies, attaining superior accuracy and resilience across diverse meteorological scenarios. The ramifications of this endeavor portend significant advancements in the strategic planning and administration of solar energy resources, thereby contributing to more dependable and efficacious renewable energy systems.
Dynamic Analysis of Laminated Composite with Inclusion
Authors: A. Usha Bharathi  , P. Irin Maria  , S. Maithreyi  , N. Soorya Sree
Published: October 2024

With growing environmental awareness, ecological concerns and new legislations, bio-fibre reinforced polymer composites have received increasing attention during the recent decades. This study focuses on the processing of seashell powder into micron size and utilizing the same as filler with glass fibres and epoxy resin in the preparation of the composite, thereby increasing mechanical strength. The constituents used in this composite showcase properties like higher strength, higher stiffness, chemical resistance, good insulation to electricity and lightweight. The components found in seashell such as Na, Ca, Al and C along with the S-glass fibre and the binding provided by the resin are responsible for enhancing hardness and tensile strength of the composite. Numerical analysis for the tensile test was done using ANSYS simulation for both composites with 5% filler (50% fibre + 45% resin+ 5% seashell) and without filler (50% fibre + 50% resin). Two laminate composites, with 5% filler (50% fibre + 45% resin+ 5% seashell) and without filler (50% fibre + 50% resin) were fabricated and their mechanical properties were compared using various tests like tensile and low velocity impact test with an impact velocity of 1 m/s, 2 m/s, 3 m/s and 4 m/s. The results from these tests were interpreted. The findings show that the specimen with 5% filler has more ultimate strength and impact strength when compared to the one without filler.
Effect of Injection Timing on Performance and Emission of a Diesel Engine using Fuelled by Hydrogen Gas
Authors: Ram Narayan Bhagat  , Kunja Bihari Sahu  , Surendra Kumar Ghadai  , Chandra Bhushan Kumar  , Ashis Kumar Saha
Published: October 2024

The injection timing of pilot fuel in diesel engine working on dual fuel mode with gaseous fuel is a very important parameter at the start of ignition which affects performance and emissions of the engine. In this regard, the experiments were conducted on single cylinder 4-stroke, direct ignition diesel engine with a power of 3.50 kW at a constant speed of 1500 RPM. Kirloskar model TV1 with diesel as pilot fuel and hydrogen as gaseous fuel was employed. Experiments were conducted with the aim to determine the effect of advancing (21o bTDC) and retarding (17o bTDC) diesel fuel injection timing on the engine performance and emissions at various load conditions with the standard injection timing of 19o bTDC.  The brake thermal efficiency (BTE) and exhaust emissions like NO­x, carbon monoxide (CO), carbon dioxide (CO­2) and hydrocarbon (HC) were analyzed with hydrogen (H2) as gaseous fuel. The results showed that dual mode (diesel and H2 gas) retards injection timing (17o bTDC) and gives a net increase in BTE efficiency at all load conditions with lower (20%) hydrogen substitution. At higher H2 substitution (40%), BTE is better for dual standard (19o bTDC) injection timing at all load conditions. Further NOx (ppm), HC (ppm), CO (%) and CO2 (%) emissions are significantly reduced with dual retard (17o bTDC) injection timing of the pilot fuel.
An Experimental Study on Algae Biodiesel with Nano-additives for Engine Performance and Emission Reduction
Authors: Amala Justus Selvam  , R. Arunraj
Published: October 2024

Introducing nano-additives like aluminum oxide and cerium oxide into the B20 blend biodiesel exhibited encouraging outcomes of combustion eﬀiciency and emission reduction. These additives likely catalyzed combustion, leading to more complete fuel burn and lower emissions. Additionally, the presence of nano-additives might have facilitated better fuel atomization and distribution within the combustion chamber, resulting in enhanced engine performance. The results indicate that adding nano-additives to biodiesel blends has significant potential for reducing environmental impact and enhancing engine longevity and efficiency. Moreover, the utilization of nano-additives represents a promising avenue for addressing the dual challenges of energy sustainability and environmental preservation. By harnessing the synergistic effects of nano-scale materials, such as aluminum oxide and cerium oxide, in biodiesel formulations, engineers and researchers can strive towards developing cleaner and more eﬀicient propulsion systems. This holistic approach underscores the importance of cooperation across disciplines between materials science, engineering, and environmental studies to advance the frontiers of sustainable energy technologies. The study attempted to improve combustion efficiency and reduce emissions by introducing nano-additives like aluminum oxide and cerium oxide into B20 biodiesel. The outcome showed enhanced engine performance, more complete fuel burn, and significant potential for reducing environmental impact.
Characterization and Ambient Temperature Hydrogen Sulfide Sensing of Annealed NiO-MnO₂ Thin Films Prepared via Jet Nebulizer Spray Pyrolysis
Authors: S. Saranya  , N. Sethupathi  , P. Mahalingam  , P. Sivakumar
Published: October 2024

A jet nebulizer spray pyrolysis technique to synthesize NiO-MnO2 thin films was demonstrated. These nanosheets were annealed at 350, 450 and 550 °C for 2 hours. The thin films surface morphology and structure were characterized using scanning electron microscopy, XRD, and UV spectroscopy. Subsequently, utilized as gas sensors for the detection of hydrogen sulphide gas. The introduction of NiO into MnO2 nanosheets significantly improved the gas-sensing performance. Notably, the gas-sensing response of the NiO-MnO2 nanosheet sensor surpassed that of both NiO and MnO2 alone, reaching a notable value of 165 when detecting 100 ppm hydrogen sulfide gas with the NiO-MnO2 thin film sensor. A remarkable feature of the NiO-MnO2 thin film sensor is its accelerated response time, registering at 10 seconds when exposed to 100 ppm of hydrogen sulfide gas. The mechanism underlying gas sensing and the factors contributing to the enhanced gas response of NiO-MnO2 thin film is thoroughly discussed. From a broader perspective, these developed sensors present a novel platform for the identification and monitoring of hydrogen sulfide gas, showcasing significant advancements in gas-sensing technology.
Experimental Investigation of the Durability of Ambient-Cured Metakaolin-Based Geopolymer Concrete in Different Sustainable Environmental Conditions
Authors: M. Nanthini  , R. Ganesan  , V. Jaganathan
Published: October 2024

Geopolymer concrete (GPC) has received much attention among researchers in recent decades due to its increased durability properties. It helps reduce massive pollution and high energy consumption during cement production. Various cementitious materials having high alumino-silicate, such as, fly ash (FA), ground granulated blast furnace slag (GGBS), rice husk ash (RHA), and metakaolin (MK), are typically used for producing GPC. These materials are activated by an alkaline solution through a polymerization process. This study examined the durability properties of metakaolin-based GPC with fly ash and GGBS under ambient curing conditions (23 ± 20 ℃). The mechanical characteristics like compressive strength, splitting tensile strength, flexural strength, and durability properties like the sorptivity volume of permeable voids exposed to chloride, sulphate, and acid environments were studied and reported. Also, an effort has been made to establish a relationship among the mechanical properties. The test results show that better performance of GPC can be achieved with 40% replacement of MK with 10% FA and 50% GGBS under ambient curing than controlled concrete. The MK-GPC with a higher proportion of metakaolin, showed good resistance to environmental factors. It is a potential alternative to conventional cement concrete.
Fabrication and Thermal Analysis of Nano-structured Heat Transfer Medium and Novel Conical-shaped Solar Greenhouse Device
Authors: R. Ranjith  , P. J. Jegan Babu  , R. V. Jeba Rajasekhar  , K. Pitchaimani
Published: October 2024

The solar device that acts on the principle of greenhouse effect is a solar greenhouse device and it is a feasible option for photothermal applications. Its optical characteristics, thermal properties, and thermal performances are to be improved for its effective utilization in application sectors. From these perspectives, the initial part of the present research was devoted to preparing, characterizing, and evaluating the nano-based heat transfer medium. The central part of the present research was devoted to fabricating the novel conical-shaped solar greenhouse device integrated with the nano-based heat transfer medium; the final part was devoted to experimentally evaluating the thermal performances of the fabricated solar greenhouse device. In the present research work, the carbon nanotube and nano-tungsten carbide-coated heat transfer medium and novel solar greenhouse device were developed and they were experimentally analyzed. The characterization studies showed that the chemical constituents in the coating affecting the heat transfer medium were in nano-sizes. The thermal studies showed that the maximum temperature enhancement on heat transfer medium with nano-coating was in the range of 49.0 to 76.2 °C. The performance study showed that the maximum drying efficiency of the conical-shaped solar greenhouse device varied from 63.9 to 66.7% for drying the leaves of medicinal plants. The novelty of the present work was not only the preparation of a nanostructured heat transfer medium but also the fabrication and utilization of a novel solar greenhouse device. Since the physical characteristics of the components and devices were found to be satisfactory, it could be concluded that the components and conical-shaped greenhouse devices would effectively be utilized in energy-intensive sectors.
Assessing the Durability, Mechanical, and Microstructural Properties of Nanosilica-enhanced Coconut Shell Concrete: A Sustainable Approach
Authors: Damodaran Pooja , Manigandan Nagarajan  , Lakshmi Thangasamy
Published: October 2024

This study explores the properties of concrete as a sustainable substitute for cement through the use of nanosilica in an eco-friendly aggregate system. Daily life generates a larger amount of coconut shell waste from the tropical zone. In India, the yearly deposition of coconut shell is about 80,000 tonnes, which is 6.7% of total agricultural waste. Crushing gravel production emits CO2, which is an environmental concern. Simultaneously, to diminish waste disposal of coconut shell can be effectively utilised as coarse aggregate in lightweight concrete. The conventional concrete (CC) was fully replaced by coconut shell coarse aggregate and crushed gravel sand (Msand) as fine aggregate in plain Portland cement. Nanosilica replaces cement in the conventional blend at 0%, 1%, 2%, 3%, and 4%. This study describes the concrete's hardened properties, such as compressive strength, splitting tensile strength, and flexural strength. Among all the mechanical performances, the N2 blend is significant. The N2 mix exhibits a trend that aligns with the correlation between compressive strength and splitting tensile strength. The transport durability performance related to capillary wick action of the optimum blend (N2 mix) has 0.018 mm/min0.5. The pore filler mechanism and pozzolanicity of 2% NS is more synergic than other combinations. The N2 mix in H2SO4 environment has less mass and strength loss. The N2 blend's morphology is robust relative to the CC mix because of the secondary C-S-H gel and homogeneous, smooth hydrated grain. As a result, the report concludes that using coconut shell as an aggregate in concrete can reduce waste disposal in landfills, while using nanosilica in place of cement can reduce CO2 emissions.
Layout design of densest weakly coupled multi-core fibers to minimize the network blocking rate
Authors: Seki Yuya , Tanigawa Yosuke , Hirota Yusuke , Tode Hideki
Published: October 2024

The suppression of inter-core crosstalk (IC-XT) that affects each lightpath is crucial for resource allocation in space-division multiplexing elastic optical networks (SDM-EONs) with multi-core fibers (MCFs). Resource allocation approaches that limit the simultaneous use of adjacent cores in the same frequency band to the MCFs composing each lightpath have been widely adopted to suppress IC-XT. However, in principle, such methods are inefficient because they cannot fully utilize all cores. This study examines the core density from the perspective of the core layout in weakly coupled MCFs and the IC-XT suppression requirement. The densest MCF layout maximizes the network capacity while restricting the amount of IC-XT within the tolerance threshold for each lightpath. Specifically, we propose an XT-free condition, maintaining the IC-XT to each lightpath within the acceptable tolerance level. In addition, we evaluated numerous MCFs that satisfy or do not satisfy the XT-free condition with various network topologies and cladding diameters. This evaluation also validates the IC-XT reduction performance of the proposed framework compared with that of the conventional resource-allocation approach. Here, we incorporate our indirect IC-XT calculation method that affects lightpaths from other cores via its nearest cores, which was overlooked in the resource allocation problem. Based on these comprehensive examinations, we propose a method to determine the densest core layout for a given network topology and route and modulation format selection algorithm.
Discrete-variable quantum key distribution services hosted in legacy passive optical networks [Invited]
Authors: Gagliano Alessandro , Gatto Alberto , Boffi Pierpaolo , Martelli Paolo , Parolari Paola
Published: October 2024

Fiber-based quantum key distribution (QKD) systems are mature and commercialized, but their integration into existing optical networks is crucial for their widespread use, in particular in passive optical networks (PONs) if end-to-end quantum-secured communications are to be addressed. While discrete-variable QKD coexistence with classical channels is well-studied in point-to-point links, its performance in point-to-multipoint topologies like PONs has received less attention. We thus developed a numerical tool to estimate quantum-available bandwidth and maximum link lengths for QKD systems in single-fiber PON architectures in coexistence with GPON, XG-PON, NG-PON2, and HS-PON standards. The QKD channel performance is obtained by setting thresholds on the quantum bit error rate and the secret key rate, ultimately limited by spontaneous Raman scattering noise and high optical distribution network losses. We perform a comparison between the performance obtained assuming the asymptotic infinite-key generation rate or taking into account actual implementations in the finite-key regime. We evidence that proper design rules can be obtained as a function of both classical and quantum system parameters to support end-to-end quantum security services in existing optical networks.
Suppression of the Petermann noise factor in a chiral optical mode converter without encircling an exceptional point
Authors: Ghosh Shamba , Roy Arpan , Dey Sibnath , Pal Bishnu P. , Ghosh Somnath
Published: October 2024

The engineering of exceptional points (EP) in gain-loss-assisted optical systems has recently garnered considerable attention for the development of unconventional photonic components. Moreover, the substantial noise associated with EPs poses a significant challenge to realizing their full potential in applications. There is a gap in the exploration of asymmetric mode conversion phenomena in the close proximity of the dynamical encirclement around an EP. In response, we propose the design of a fabrication-feasible dual-mode optical planar waveguide. Non-Hermiticity, in terms of a customized gain-loss profile, is introduced to modulate the interaction between the coupled modes. Contrary to previous assumptions, we establish that the dynamical encirclement of an EP is not a prerequisite for achieving asymmetric mode conversion. Furthermore, we calculate the Petermann factor (K) near the EP and demonstrate a significant two orders of magnitude reduction in the Petermann noise factor when we do not dynamically encircle the EP. Hence, we propose a new scheme to reduce the inherent noise.
Pre- and post-compensation to suppress birefringent walk-off effects of entangled photons
Authors: Feng Tianxuan , Fan Rong , Fan Ronghua , Wang Conghao , Huang Chao , Li Ang , Zhang Hanyi , Cao Yin , Li Lijing
Published: October 2024

Photon-based entanglement sources, crucial for obtaining entangled states, are typically generated via spontaneous parametric down-conversion. However, birefringence in nonlinear crystals causes spatial or temporal walk-off, reducing entangled photon quality. The theoretical analysis attributes birefringent walk-off to dispersive materials curbed by pre- and post-compensation. We experimentally validate this method, enhancing polarization-entangled photon quality. We measured the Bell state along with a violation of CHSH-Bell’s inequality by ∼366 standard deviations (S = 2.623 ± 0.0017). Our approach, simple and stable, does not complicate setups. Its applicability extends to optimizing various entanglement source schemes, aiding optical quantum technologies such as computation, sensing, and communication.
4D Vis-SWIR line-scan hyperspectral imaging
Authors: Li Jiaqiong , Liu Lingling , Li Beiwen
Published: October 2024

This paper proposes a four-dimensional (4D) line-scan hyperspectral imaging system to acquire 3D spatial data and hyperspectral images covering from visible to short-wave infrared (Vis-SWIR) wavelength range. The system captures visible and near-infrared (VNIR) and SWIR hyperspectral images using two line-scan sensors, while 3D spatial data is acquired via a fringe projection profilometry subsystem. To align the VNIR and SWIR hyperspectral images, we utilize a line-scan homography method and propose a transformation method to register 3D spatial data with hyperspectral images. The mean reprojection error for hyperspectral image registration is 0.5396 pixels, and the registration of 3D spatial data with hyperspectral images achieves subpixel accuracy. Spatial accuracy is demonstrated with a root mean squared error (RMSE) of 0.1321 mm and a mean absolute error (MAE) of 0.1066 mm by measuring a standard sphere with a 20.0512 mm radius. The spectral resolutions are 11.2 nm in the VNIR range and 5 nm in the SWIR range. Two case studies were conducted: one involving a colorful object with rich features and colors, and another involving a potato before and after sprouting. Results from the measurement of a colorful object demonstrate the proposed system’s registration accuracy and image intensity variation across wavelengths, while the potato study highlights the system’s potential applications in the food industry.
Enhanced stimulated Raman and fluorescence imaging by single-frame trained BDN
Authors: Tang Xiaobin , Zhang Yongqing , Huang Xiangjie , Lee Hyeon Jeong , Zhang Delong
Published: October 2024

Hyperspectral and multispectral imaging capture an expanded dimension of information that facilitates discoveries. However, image features are frequently obscured by noise generated from the limited photodamage threshold of the specimen. Although machine learning approaches demonstrate considerable promise in addressing this challenge, they typically require extensive datasets, which can be difficult to obtain. Here, we introduce BiFormer denoising network (BDN), designed to effectively and efficiently extract image features by utilizing both local and global level connections, sparse architectures, and fine-tuning. Experimental results indicate that BDN enhances the quality of stimulated Raman scattering (SRS) images by up to 16-fold in signal-to-noise ratio (SNR), particularly improving subtle features at higher spatial frequencies. Furthermore, BDN is successfully adapted to fluorescence imaging, achieving significant improvements in SNR and order-of-magnitude reduction in exposure time, thereby showcasing its versatility across various imaging modalities. Collectively, BDN exhibits substantial potential for spectroscopic imaging applications in the fields of biomedicine and materials science.
Plasmonic modulators based on enhanced interaction between graphene and localized transverse-electric plasmonic mode
Authors: Hou Anle , Wang Yulin , Geng Feihu , Zhang Yong , Huang Chengping , Zhou Lin
Published: October 2024

Active plasmonic modulators with high modulation depth, low energy consumption, ultra-fast speed, and small footprint are of interest and particular significance for nanophotonics and integrated optics. Here by constructing a transverse-electric (TE) plasmonic mode and maximizing the in-plane component localized on the graphene surface, we propose a high-performing plasmonic modulator based on a graphene/split ring-like plasmonic waveguide (SRPW) system with a record high modulation depth (20.46 dB/µm) and suppressed insertion loss (0.248 dB/µm) at telecom wavelength 1310 nm, simultaneously possessing pronounced advantage in broadband ability (800-1650 nm) and superior electrical performance with energy consumption of 0.43 fJ/bit and modulation speed of 200 GHz. This innovative design provides a novel approach and idea for enhancing the interaction between light and matter in the waveguide system and will certainly inspire new schemes for the development of on-chip integrated optoelectronic devices.
Polarization-multiplexed zoom Moiré metalens for edge-enhanced imaging
Authors: Liu Yongqi , Chi Cheng , Shan Yuefan , Cheng Dewen , Wang Yongtian
Published: October 2024

Optical image processing with high operational efficiency has been applied as a pre-processing imaging system for image recognition. Edge-enhanced imaging as a high-efficiency optical image processing method is of great significance for feature extraction and target recognition. However, the edge-enhanced imaging system based on the 4F system and the spatial filter transforms mainly work under coherent light illumination conditions, without continuously zooming to track the spatial position of the target. Here, we demonstrate a polarization-multiplexed zoom Moiré metalens for edge-enhanced imaging under incoherent light illumination. Metalens is designed to generate polarization-dependent optical transfer functions that produce edge-enhanced images with a resolution of 1.2 µm by digital subtraction. Furthermore, continuous zoom at the range of 1-2× is realized by constructing a Moiré metalens composed of cascaded metasurfaces. The cascaded metasurfaces consist of two center-aligned dielectric metasurfaces, each with a Moiré phase sensitive to the rotation angle. By rotating the metasurface, the phase profile of the cascaded metasurfaces changes, and the effect of continuous zoom is realized. The focal length can be actively changed from 38 µm to 77 µm with the focusing efficiency of 50.3%. This metalens can be applied to machine vision, microscopic imaging, and promotes the development of multi-functional integrated optical systems.
Pulse compressor architecture to enable next-generation high-energy petawatt-class lasers
Authors: Alessi David A. , Bude Jeff D. , Nguyen Hoang T. , Jackson Williams G. , Siders Craig W. , Spinka Thomas M.
Published: October 2024

The maximum energy obtainable within a single aperture of a high-energy petawatt-class (HEPW) laser is typically limited by the pulse compressor. This work evaluates the potential impact of two new pulse compression grating technologies (HELD gratings and TM polarization) on HEPW laser systems. A compressor architecture is proposed that implements these grating advancements in order to support ∼6× higher pulse energies than currently demonstrated. This increase in energy and intensity could have substantial benefits to high-flux secondary sources and enable new applications.
Femtosecond Mamyshev fiber oscillator started by ultra-low power microchip laser seeder at two different wavelengths: a comparison
Authors: Gotti Riccardo , Pizzurro Sara , Canella Francesco , Giannotti Dario , Galzerano Gianluca , Agnesi Antonio , Pirzio Federico
Published: October 2024

A 1-W average output power, sub-60-fs femtosecond Mamyshev fiber oscillator was reliably started by a passively Q-switched sub-ns microchip laser generating four-wave-mixing signals in a polarization-maintaining passive fiber, at either 1064 nm or at 1033 nm. We show experimentally that seeding at 1033 nm provides much higher quality pulses with a duration as short as 41 fs and minimal satellites. The evolution toward the gain-managed nonlinear amplification regime clearly takes place when seeding the oscillator closer to the peak gain of the Yb-doped fiber.