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Number of results: 3
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Abstract

Groundwater mapping plays an important role in effective water resource management, sustainable development, and environmental protection. In the tropical Brunei Darussalam (north Borneo Island), groundwater mapping is yet to be provided. The aim of the study is to provide groundwater mapping of Brunei, particularly for the urban and coastal areas of the Brunei-Muara capital district. The study uses a GIS interpolation technique to generate a groundwater contour map based on groundwater data from 572 sacrificial boreholes located in the study area. Remote sensing data and published maps from secondary sources were digitised in ArcGIS software to produce thematic layers for further hydrological evaluations. Results showed that groundwater levels in the study area are generally high and shallow, ranging from 0 to 18 m below ground level with a mean value of 2.9 m. According to the evaluation of geo-thematic layers and groundwater contours, groundwater flows towards the South China Sea in the coastal areas and towards the Brunei River further inland. Hydraulic gradients towards the South China Sea also vary between 0.004 and 0.08. Thus, assuming surface aquifer thickness in the weathered zone between 10 to 20 m, hydraulic conductivities ranges from 1∙10−5 to 1∙10−4 m∙s−1, a submarine groundwater discharge (SGD) flux between 4.7∙10−7 to 4.0∙10−4 m3∙s−1 per unit width can be estimated for the shallow aquifer. This study provides valuable insights into the groundwater system dynamics so important, which are critical for its future utilisation and protection, aiming to contribute to the national water security in Brunei Darussalam.
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Authors and Affiliations

Hakimmi Abidin
1
ORCID: ORCID
Siti Lieyana Azffri
1
ORCID: ORCID
Emelia Nirus
1
ORCID: ORCID
Asri Suhip
2
ORCID: ORCID
Afiq Aiman Jaya
2
ORCID: ORCID
Stefan Herwig Gödeke
1
ORCID: ORCID

  1. Universiti Brunei Darussalam, Geoscience Programme, Faculty of Science, Jalan Tungku Link, Gadong, BE1410, Bandar Seri Begawan, Brunei Darussalam
  2. Ministry of Development, Public Works Department, Geological and Geotechnical Section, Jalan Lapangan Terbang Lama, Berakas, BB3510, Bandar Seri Begawan, Brunei Darussalam
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Abstract

A five-year of monitoring (2018–2022) of the loggerhead sea turtle Caretta caretta nests in “Pozzolana di Ponente” beach on Linosa Island (Pelagie Archipelago, Italy) is here reported. To explore how temperatures affect the hatching success and the possible occurrence of any malformation in hatchlings, incubation temperature values were recorded using data loggers positioned at depths of 5 and 35 cm (for each nest) from the surface, approximately 0.5 m from the nest chamber. The obtained results highlighted important issues related to the success of hatching and the incidence of body anomalies. The temperatures recorded at different depths near the nests (5 and 35 cm) in some periods of incubation of the eggs were above optimal development temperature (i.e., ~33°C), causing high mortality rates, especially during the first two years of the survey (2018–2019). In the next three years (2020–2022), the implementation of shading cover cloths of the nests increased the survival rate and decreased the incidence of malformed individuals. Furthermore, atmospheric temperature data were extrapolated from the “Copernicus Climate Change” web service and included in our analyses to assess any changes over the timeframe analysed. Over five years (2018–2022), the average atmospheric temperature increased slightly by 1.7°C. In light of global warming, the implementation of effective and low-cost mitigation activities, such as the use of shade cloth covers to protect the nests from overheating, should be considered a suitable conservation action.
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Authors and Affiliations

Luca Vecchioni
1
ORCID: ORCID
Andrea Citarrella
1
ORCID: ORCID
Irene Cambera
2
ORCID: ORCID
Antonella Di Gangi
2
ORCID: ORCID
Dario D’Emanuele
2
ORCID: ORCID
Lucia Ventura
2
ORCID: ORCID
Elena Principato
2
ORCID: ORCID
Giulia Visconti
3
ORCID: ORCID
Marco Torri
4
ORCID: ORCID
Francesco P. Faraone
1
ORCID: ORCID
Marco Arculeo
5
ORCID: ORCID

  1. University of Palermo, Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), Via Archirafi, 18, 90123, Palermo, Italy
  2. Area Marina Protetta (AMP) Isole Pelagie, Via Cameroni, 92010, Lampedusa, Italy
  3. University of Palermo, Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), Via Archirafi, 18, 90123, Palermo, Italy; Area Marina Protetta (AMP) Capo Milazzo, Via Francesco Crispi, 1, 98057, Milazzo, Italy
  4. National Research Council of Italy, Institute for Studies on the Mediterranean (ISMed-CNR), Via Filippo Parlatore, 65, 90145, Palermo, Italy
  5. Arculeo, Marco : University of Palermo, Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), Via Archirafi, 18, 90123, Palermo, Italy
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Abstract

During the next generation of wireless cellular networks, the millimeter-wave (mm-wave) spectrum will bring new opportunities for exceptionally high data transfer speeds and extensive network connectivity. Millimeter waves, on the other hand, are subject to a significant loss of propagation, which is the most significant impediment. A beneficial solution to this difficulty, which can be overcome, is to use a beam-forming system that consists of many antennas. The purpose of this study is to provide a concept for an integrated photonic beam-forming system that utilises multiple ring resonators for a 1 × 4 phase array antenna operating in the Ka-Band frequency range. The waveguide technology is the foundation for a signal that operates at 28 GHz. It is through the use of the optical ring resonator that the actual time delay line may accomplish its goal. The suggested method can be imDuring the next generation of wireless cellular networks, the millimeter-wave (mm-wave) spectrum will bring new opportunities for exceptionally high data transfer speeds and extensive network connectivity. Millimeter waves, on the other hand, are subject to a significant loss of propagation, which is the most significant impediment. A beneficial solution to this difficulty, which can be overcome, is to use a beam-forming system that consists of many antennas. The purpose of this study is to provide a concept for an integrated photonic beam-forming system that utilises multiple ring resonators for a 1 × 4 phase array antenna operating in the Ka-Band frequency range. The waveguide technology is the foundation for a signal that operates at 28 GHz. It is through the use of the optical ring resonator that the actual time delay line may accomplish its goal. The suggested method can be implemented as a variable true time delay (TTD) line to change the radiation angle of phase array antennas (PAA). The main lobe radiated by the PAA can be directed squint-free between the angles from −28° to +28°. The mathematical analysis and design of the beam producing the structure are presented. Following that, delays of 650 ps, 350 ps, and 250 ps could be produced with coupling coefficients of κ = 0.5 , κ = 0.7, and κ = 0.9 , respectively, and the associated phase shifts were 0.469π, 0.146π, and 0.387π.plemented as a variable true time delay (TTD) line to change the radiation angle of phase array antennas (PAA). The main lobe radiated by the PAA can be directed squint-free between the angles from −28° to +28°. The mathematical analysis and design of the beam producing the structure are presented. Following that, delays of 650 ps, 350 ps, and 250 ps could be produced with coupling coefficients of κ = 0.5 , κ = 0.7, and κ = 0.9 , respectively, and the associated phase shifts were 0.469π, 0.146π, and 0.387π.
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Authors and Affiliations

Md. Danish Nadeem
1
Sanjeev Kumar Raghuwanshi
1
Ritesh Kumar
2

  1. Microwave Photonics Laboratory, Department of Electronics Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad Jharkhand-826004, India
  2. Shri Phaneshwar Nath Renu Engineering College, Araria, Bihar 854318, India

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