Jurnal Fisika Unand
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Pengaruh Geometri dan Polarisasi Cahaya terhadap Resonansi Plasmon Nanopartikel Ellipsoid Core-Shell SiO₂@Ag dan SiO₂@Au
Get PDFThis study reports the optical behaviors of SiO₂@Ag and SiO₂@Au core-shell ellipsoidal nanoparticles in terms of polarization of light and geometrical parameter changes. The particles showed two strong modes of resonances, longitudinal and transversal, which could be controlled by rotating the polarization of incident light by 90° and thus could find applications as sensor and optical switch devices. While the resonant wavelength is independent of polarization direction, while maximum extinction values indicate pronounced changes. SiO₂@Ag nanoparticle exhibit higher maximum extinction as well as the peak of resonance at a shorter wavelength than SiO₂@Au. Furthermore, an increase in the ratio of core diameter to shell induces a blue-shift and increasing extinction value. The overall particle size has no influence on the location of the peak of the resonance but increases the extinction intensity. The larger ratio of short axis to long axis also brings about blue-shift in longitudinal resonances. The finding demonstrates that core-shell structure control and morphology control can be used to engineer nanoparticle optical performance in diverse nanophotonic applications.Studi ini menjelaskan perilaku optik nanopartikel elipsoidal core-shell SiO₂@Ag dan SiO₂@Au akibat perubahan polarisasi cahaya dan parameter geometri. Partikel menunjukkan dua mode resonansi yang kuat, longitudinal dan transversal, yang dapat dikontrol dengan memutar polarisasi cahaya datang sebesar 90° dan dengan demikian dapat menemukan aplikasi sebagai sensor dan perangkat saklar optik. Sementara panjang gelombang resonansi tidak tergantung pada arah polarisasi, nilai extinction maksimum menunjukkan perubahan signifikan. Nanopartikel SiO₂@Ag menunjukkan extinction maksimum yang lebih tinggi serta puncak resonansi pada panjang gelombang yang lebih pendek daripada SiO₂@Au. Lebih jauh lagi, peningkatan rasio diameter teras terhadap kulit menginduksi pergeseran biru yang diikuti peningkatan extinction maksimum. Ukuran partikel keseluruhan tidak memiliki pengaruh pada lokasi puncak resonansi tetapi meningkatkan intensitas extinction. Rasio sumbu pendek terhadap sumbu panjang yang lebih besar juga menyebabkan pergeseran biru pada resonansi longitudinal. Penemuan ini menunjukkan bahwa kontrol struktur core-shell dan kontrol morfologi dapat digunakan untuk merekayasa kinerja optik nanopartikel dalam berbagai aplikasi nanofotonik
Studi Komparatif Triangular dan Quadrilateral Mesh pada Inversi Geolistrik 2D Wenner-Schlumberger untuk Zona High resistivity di Terowongan 11 Padalarang
Get PDFThis study aims to compare the results of 2D electrical resistivity inversion using triangular and quadrilateral mesh types in the Wenner–Schlumberger configuration to identify high-resistivity zones at Tunnel 11, Padalarang. Data acquisition was performed using 48 electrodes with a 10 m spacing and an ARES II multichannel resistivity meter. Data inversion was conducted with the ResIPy software employing two different mesh approaches. The results show that the triangular mesh produces smoother models, better adapts to topography, and achieves lower root mean square (RMS) errors (1.09–1.12%) compared to the quadrilateral mesh (4.67–4.72%). High-resistivity zones (>60 Ωm), interpreted as andesitic basalt, were identified at depths greater than 25 meters. The extent of these zones increases from Line 2 to Line 1, which has implications for blasting or drilling strategies during tunnel construction. These findings indicate that triangular mesh is more effective for complex geological conditions.Penelitian ini bertujuan untuk membandingkan hasil inversi data geolistrik 2D menggunakan tipe triangular meshdan quadrilateral pada konfigurasi Wenner–Schlumberger untuk mengidentifikasi zona resistivitas tinggi di Terowongan 11 Padalarang. Akuisisi data dilakukan dengan 48 elektroda dan spasi 10 m menggunakan alat resistivitymeter ARES II multichannel. Proses inversi dilakukan dengan perangkat lunak ResIPy menggunakan dua pendekatan mesh yang berbeda. Hasil menunjukkan bahwa triangular meshmenghasilkan model yang lebih halus, adaptif terhadap topografi, dan memiliki nilai root mean square (RMS) error lebih rendah (1,09–1,12%) dibandingkan quadrilateral mesh (4,67–4,72%). Zona resistivitas tinggi (>60 Ωm) yang diinterpretasikan sebagai batuan andesitic basalt teridentifikasi pada kedalaman lebih dari 25 meter. Sebaran zona tersebut meningkat dari Lintasan 2 ke Lintasan 1, yang berimplikasi terhadap metode peledakan atau pengeboran pada konstruksi terowongan. Hasil ini menegaskan bahwa triangular meshlebih efektif digunakan pada kondisi geologi kompleks
Understanding anti-consumption and consumer reluctance toward foreign agri-food products: country of origin and perceived value in times of image crisis
No full textPurpose
Globalization has increased the importance of understanding consumer behavior, including anti-consumption tendencies, toward agri-food products, particularly in contexts where a sector or country faces an image crisis. This study aims to identify the key factors influencing consumer reluctance to buy (RTB) foreign agri-food products – a form of anti-consumption – with a specific focus on the role of country of origin in decision-making. By analyzing these variables, the research seeks to provide insights that can help businesses and policymakers develop more effective strategies to address consumer concerns and improve market positioning.
Design/methodology/approach
A conceptual model is proposed suggesting that RTB foreign agri-food products can be mitigated by consumer affinity toward a foreign country and other key variables such as country image and perceived value, counteracting consumer ethnocentrism, notably when image crises affect a country-product. The empirical study focuses on the Spanish agri-food sector, using data from 335 German consumers. Partial least squares structural equation modeling (PLS-SEM) was employed to analyze the relationships within the model.
Findings
Results indicate that affinity toward a foreign country and perceived value significantly reduce RTB of foreign agri-food products, whereas consumer ethnocentrism increases RTB. Moreover, the study reveals that image crises moderate these relationships.
Originality/value
This study provides original insights by investigating the agri-food sector and the nuanced impact of country image and consumer affinity in mitigating RTB, a manifestation of potential anti-consumption, within this context. Notably, it offers novel empirical evidence on how image crises concerning a country-product dynamically moderate the influence of these key variables
Control del confort térmico mediante aprendizaje por refuerzo en edificios
No full textEl confort térmico se puede definir como la sensación que garantiza la satisfacción de una persona con el ambiente térmico que le rodea. Por tanto, garantizar esa sensación de bienestar de forma eficiente es un factor clave desde el punto de vista del ahorro de energía, ya que minimiza los costes y el impacto ambiental derivado de asegurar un ambiente confortable. En este trabajo, se propone un controlador que utiliza aprendizaje por refuerzo para mantener el confort térmico de los usuarios del centro de investigación CIESOL. Para ello, se ha hecho uso de un modelo lineal simplificado de la temperatura del aire interior de una habitación, que ha sido validado con datos reales del edificio. Además, se han entrenado dos agentes diferentes: un agente de Gradiente de Política Determinista Profunda (DDPG) y un agente de Gradiente de Política Determinista Profunda de Doble Retardo (TD3). Los resultados obtenidos en simulación muestran cómo el controlador propuesto es capaz de mantener la temperatura interior en la referencia establecida, incluso ante la presencia de perturbaciones. Finalmente, el desempeño del controlador propuesto se ha comparado con un clásico controlador Proporcional-Integral-Derivativo (PID)
Environmental Footprint Assessment and Mitigation Strategies in Agricultural Cooperatives: A Case Study towards Cleaner Production in Arid Regions
No full textCarbon and water footprint methodologies are widely used in agri-food systems, yet their organisational application, particularly in cooperatives, remains limited. This study addresses this gap by quantifying the carbon footprint (CF) and water footprint (WF) of a Mediterranean horticultural cooperative in production, packaging, and distribution, and linking the results to targeted mitigation actions.
Results showed that 76.26% of total greenhouse gas emissions were concentrated in a small set of processes and inputs. Blue water use also clustered in a few hotspots related to irrigation practices and post-harvest handling. Based on these findings, we designed a portfolio of measures that includes sensor-based irrigation, photovoltaic self-consumption, composting of organic residues, integrated pest management, and sustainable procurement. Scenario analysis indicates that this portfolio could reduce CF and WF by 20%–30% over three years without compromising productivity.
Sensitivity analysis confirms the robustness of the results and highlights the role of data quality and boundaries. The study provides a practical roadmap for cooperatives seeking measurable reductions in emissions and water use, with transparent, accountable monitoring and reporting.
This work demonstrates a scalable, data-informed approach that connects footprint indicators with decisions at the organisational level. It aligns technical actions with policy goals, including the Sustainable Development Goals and the European Green Deal. The approach is transferable to other semi-arid regions that face resource constraints and rising decarbonisation pressure. The results support circular economy and sustainable production and consumption and provide evidence to inform mitigation and Environmental Impact Assessment
Development of a culturally competent training curriculum for healthcare professionals to promote vaccination and tackle vaccine hesitancy: A Delphi study
No full textA B S T R A C T
Background: Addressing vaccine hesitancy is crucial, especially when considering cultural factors. This article
outlines the creation of a training curriculum model designed to equip healthcare professionals with the essential
knowledge, expertise, and cultural competency required to effectively promote vaccination and tackle vaccine
hesitancy.
Methods: A two-round Delphi Study with 23 experts from four European countries—Spain, Greece, Romania, and
Cyprus — and diverse backgrounds, based on predetermined criteria, was undertaken. The aim was to identify
key topics, through purposive sampling, ensuring diversity and representativeness within the participant group.
The process generated valuable insights and highlighted the significance of all statements in culturally sensitive
vaccination practices. Five statements from each module were chosen as the fundamental content of the curriculum.
These selections were based on mean scores, range, and median values.
Results: The curriculum model reflects the collective insights of experts, paving the way for improved vaccination
advocacy and community engagement. It encompasses four modules based on the Papadopoulos Tilki and Taylor
(PPT) model for cultural competence, each targeting specific learning objectives to enhance healthcare professionals’
abilities in advocating for vaccination and providing culturally appropriate care for population groups
in diverse cultural contexts.
Conclusion: The training curriculum model emphasizes intercultural communication, empowerment, and advocacy,
offering a holistic strategy for promoting vaccination acceptance. It is crucial for healthcare professionals to
possess the necessary knowledge, skills, and resources to effectively protect the health and welfare of communities.
This, in turn, contributes to the development of enduring, fair, and robust healthcare systems
Astrateutoi y Androgynai en la concepción grecolatina de la alteridad
No full textEn la antigüedad grecorromana la condición de guerrero-propietario-ciudadano es clave para el mantenimiento de su estructura económica, militar y política. Por tanto, ante las realidades no plenamente viriles, “los unos”, la literatura y la narrativa histórica, han visto al “otro”, y lo han marcado con el recurso al estereotipo: debilidad, cobardía, ineptitud para la dignitas y para el cursus honorum, así como objetos de placer; y de ahí que también se enfatice una forzada conexión entre los insumisos del servicio militar y los andróginos en la esfera teatral
Motivações e expectativas dos estudantes de um programa universitário para adultos mais velhos em relação ao e-learning
No full textObjective. The University Programmes for Older Adults, aimed at people over 55 years of age, include among their objectives educational and social inclusion through lifelong learning. The health crisis caused by COVID-19 led some of these programmes to teach in virtual mode in the 2020-2021 academic year. This study analyzes the impact of this change on students' motivations and expectations towards the online learning process. Methodology. A mixed qualitative and quantitative methodology is used so that the 230 students enrolled in the University of Almeria's Senior University are asked to answer a structured questionnaire on these motivations and expectations, so that a total of 62 students voluntarily agreed to participate in the study. The collection of information is articulated through an online questionnaire validated by triangulation and expert judgement and various official documentation of the university program for seniors. Results. The existence of resistance to the substitution of face-to-face teaching by virtual teaching is detected, although the majority of the students would continue the training process the following year, regardless of the teaching mode offered. The heterogeneity of the group of students, who avoid being pigeonholed as a homogeneous group, is also evident, as can be seen from the motivations, perceptions, and expectations about the learning process that they state. Conclusions. The students assume that distance learning is an exceptional circumstance linked to the pandemic, and although there is resistance to online versus face-to-face teaching, they show great interest in the training program and wish to continue with it
Microclimate Characterization of a Low-Tech Greenhouse During a Tomato Crop (Solanum lycopersicum L.) Production Cycle in Chaltura, Imbabura
No full textGreenhouse agriculture is experiencing global expansion; however, in Andean countries
such as Ecuador, its development is constrained by low-tech infrastructure, limited automation,
and insufficient environmental monitoring, all of which negatively affect productivity
and fruit quality. This study characterized the microclimate of a low-tech greenhouse
in Chaltura, Imbabura Province, during a complete production cycle of tomato crop
(Solanum lycopersicum L.). Microclimatic conditions were analyzed during three phenological
stages (vegetative, reproductive, and harvest). Temperature and relative humidity
were recorded at 5 min intervals using sensors placed in the greenhouse quadrants, while
an external weather station provided daily outdoor climate data. Statistical analyses were
performed in R software (version 4.4.x). The results revealed marked internal microclimatic
heterogeneity and showed that the crop remained outside the optimal ranges of temperature,
relative humidity, and vapor pressure deficit (VPD) for over 50% of the time across
all phenological stages and greenhouse quadrants. These findings underscore the urgent
need for cost-effective climate-control strategies adapted to local conditions and provide a
scientific basis for future research aimed at improving climatic and productive efficiency, as
well as the resilience and sustainability of protected agriculture in Andean regions
Más que una denuncia de prácticas ilícitas en la América hispana del siglo XVIII: Los Males Públicos del Perú
No full textEl presente trabajo tiene por objetivo analizar una de las denuncias envidas al rey Felipe V, que da buena cuenta de la corrupción del Reino del Perú durante el primer cuarto del siglo XVIII. Rotulado como Los Males Públicos del Perú, el interés de este documento resulta tanto de su contenido y detalle del contexto peruano, como de sus implicaciones para aproximarse a distintas dimensiones de la historia política, institucional e, incluso, social y moral del mundo hispánico del período moderno. Los resultados obtenidos apuntan a que este escrito fue mucho más que un aparente, inocente y anónimo servicio al rey en aras del bien común, y rebaten formulaciones historiográficas hasta ahora sostenidas sobre dicha denuncia