bluuebunny/crossref_metadata_2025 huggingface dataset:
Capacitive self tension sensing properties of steel beam: electrode configuration and stress regime
Authors: Ozturk Murat
Published: October 2023

A structural material is called self-sensing when it is able to reveal its own state without the need for any external sensors. Self-sensing for steel is valuable for the control and safety of steel structures such as buildings and bridges. The changes in the capacitance of steel in response to cyclic tensile stresses applied in low, medium and high stress regimes are measured by using a Inductnce-Capacitance-Resistance (LCR) meter. Coplanar and parallel plate electrode configuration is used for capacitance measurements. Aluminum foil is used as electrode. A steel beam of 100 mm in length, 30 mm in width and 2.5 mm in thickness is tensioned by holding it at both ends to produce direct tensile stresses in the material. The maximum stresses applied for low, medium and high stress regimes are 6.7 MPa, 33.3 MPa and 66.7 MPa. The capacitance value of the sample with coplanar and parallel plate electrode configurations measured without applying load are 203.42 pF and 196.00 pf, respectively. The fractional changes in capacitance are 0.059%, 0.192% and 0.275% when 6.7 MPa, 33.3 MPa and 66.7 MPa direct tensile stress is created in the steel beam. These values are 0.12%, 0.20% and 0.29% for parallel plate electrode configuration. Test results demonstrates that there is a relation between stress and fractional change in capacitance. In other words, measuring fractional change in capacitance gives information about the stress variations in the material. From the experimental results, parallel plate electrode configuration is found to be more effective in tensile stress self-sensing. In addition, the relationship between stress and fractional change in capacitance is more linear for both electrode configurations in the low stress regime. This paper aims to reveal the tensile stresses occurring in steel by means of capacitance-based sensing. Sensing capability in larger scale structures and factors effecting sensing sensitivity are to be addressed in future work.
The DESI One-Percent survey: exploring the Halo Occupation Distribution of Emission Line Galaxies with AbacusSummit simulations
Authors: Rocher Antoine , Ruhlmann-Kleider Vanina , Burtin Etienne , Yuan Sihan , de Mattia Arnaud , Ross Ashley J. , Aguilar Jessica , Ahlen Steven , Alam Shadab , Bianchi Davide , Brooks David , Cole Shaun , Dawson Kyle , de la Macorra Axel , Doel Peter , Eisenstein Daniel J. , Fanning Kevin , Forero-Romero Jaime E. , Garrison Lehman H. , Gontcho A Gontcho Satya , Gonzalez-Perez Violeta , Guy Julien , Hadzhiyska Boryana , Hahn ChangHoon , Honscheid Klaus , Kisner Theodore , Landriau Martin , Lasker James , E. Levi Michael , Manera Marc , Meisner Aaron , Miquel Ramon , Moustakas John , Mueller Eva-Maria , Newman Jeffrey A. , Nie Jundan , Percival Will J. , Poppett Claire , Qin Fei , Rossi Graziano , Samushia Lado , Sanchez Eusebio , Schlegel David , Schubnell Michael , Seo Hee-Jong , Tarlé Gregory , Vargas-Magaña Mariana , Weaver Benjamin A. , Yu Jiaxi , Zhang Hanyu , Zheng Zheng , Zhou Zhimin , Zou Hu
Published: October 2023

The One-Percent survey of the Dark Energy Spectroscopic Instrument collected ∼ 270kemission line galaxies (ELGs) at 0.8 <z< 1.6. The high completeness of the sample allowed the clustering to be measured down to scales never probed before, 0.04 Mpc/hinrpfor the projected 2-point correlation function (2PCF) and 0.17 Mpc/hin galaxy pair separation s for the 2PCF monopole and quadrupole. The most striking feature of the measurements is a strong signal at the smallest scales, below 0.2 Mpc/hinrpand 1 Mpc/hins. We analyse these data in the halo occupation distribution framework. We consider different distributions for central galaxies, a standard power law for satellites with no condition on the presence of a central galaxy and explore several extensions of these models. For all considered models, the mean halo mass of the sample is found to be log10⟨Mh⟩ ∼ 11.9. We obtain a satellite mean occupation function which agrees with physically motivated ELG models only if we introduce central-satellite conformity, meaning that the satellite occupation is conditioned by the presence of central galaxies of the same type. To achieve in addition a good modelling of the clustering between 0.1 and 1 Mpc/hinrp, we allow for ELG positioning outside of the halo virial radius and find 0.5% of ELGs residing in the outskirts of halos. Furthermore, the satellite velocity dispersion inside halos is found to be ∼ 30% larger than that of the halo dark matter particles. These are the main findings of our work. We investigate assembly bias as a function of halo concentration, local density or local density anisotropies and observe no significant change in our results. We split the data sample in two redshift bins and report no significant evolution with redshift. Lastly, changing the cosmology in the modelling impacts only slightly our results.
Chirping compact stars: gravitational radiation and detection degeneracy with binaries
Authors: Rodríguez J.F. , Rueda J.A. , Ruffini R. , Zuluaga J.I. , Blanco-Iglesias J.M. , Lorén-Aguilar P.
Published: October 2023

Compressible, Riemann S-type ellipsoids can emit gravitational waves (GWs) with a chirp-like behavior (hereafter chirping ellipsoids, CELs). We show that the GW frequency-amplitude evolution of CELs (mass ∼ 1 M⊙, radius ∼ 103 km, polytropic equation of state with index n ≈ 3) is indistinguishable from that emitted by double white dwarfs and by extreme mass-ratio inspirals (EMRIs) composed of an intermediate-mass (e.g. 103 M⊙) black hole and a planet-like (e.g. 10-4 M⊙) companion, in the frequency interval within the detector sensitivity band in which the GW emission of these systems is quasi-monochromatic.
For reasonable astrophysical assumptions, the local universe density rate of CELs, double white dwarfs, and EMRIs in the mass range here considered are very similar, posing a detection-degeneracy challenge for space-based GW detectors. We outline the astrophysical implications of this CEL-binary detection degeneracy by space-based GW-detection facilities.
Chiral asteroseismology: seismic oscillations caused by chiral transport in neutron stars and supernovae
Authors: Hanai Sota , Yamamoto Naoki
Published: October 2023

We study the novel asteroseismology of the chiral magnetic wave (CMW) of the quark number density in relativistic quark matter inside neutron stars and core-collapse supernovae and the chiral vortical wave (CVW) of the neutrino number density in relativistic neutrino matter at the core of supernovae.
We call the oscillation modes for these chiral waves the chiral magnetic mode (CM-mode) and chiral vortical mode (CV-mode), respectively.
We derive the dispersion relations of these new modes in the presence of the chirality flipping due to the finite quark mass and diffusion. We then estimate the possible frequencies of these modes and amplitudes of the resulting gravitational waves. In particular, since the CM-mode can exist only in quark matter with nearly gapless quarks (such as the two-flavor color superconductivity) for a sufficiently strong magnetic field, corresponding gravitational waves provide a new possible probe for such quark matter and the magnetic field in neutron stars.
Fast and robust Bayesian inference using Gaussian processes with GPry
Authors: El Gammal Jonas , Schöneberg Nils , Torrado Jesús , Fidler Christian
Published: October 2023

We present the GPry algorithm for fast Bayesian inference of general (non-Gaussian) posteriors with a moderate number of parameters. GPry does not need any pre-training, special hardware such as GPUs, and is intended as a drop-in replacement for traditional Monte Carlo methods for Bayesian inference. Our algorithm is based on generating a Gaussian Process surrogate model of the log-posterior, aided by a Support Vector Machine classifier that excludes extreme or non-finite values. An active learning scheme allows us to reduce the number of required posterior evaluations by two orders of magnitude compared to traditional Monte Carlo inference. Our algorithm allows for parallel evaluations of the posterior at optimal locations, further reducing wall-clock times. We significantly improve performance using properties of the posterior in our active learning scheme and for the definition of the GP prior. In particular we account for the expected dynamical range of the posterior in different dimensionalities. We test our model against a number of synthetic and cosmological examples. GPry outperforms traditional Monte Carlo methods when the evaluation time of the likelihood (or the calculation of theoretical observables) is of the order of seconds; for evaluation times of over a minute it can perform inference in days that would take months using traditional methods. GPry is distributed as an open source Python package (pip install gpry) and can also be found at https://github.com/jonaselgammal/GPry.
Tuning stability enhancement of all-fiber acousto-optic tunable filter based on multi-piezoelectric transducer
Authors: Qiu Feng , Bai Yongzhong , Qu Dingrong , Shan Guangbin , Han Lei , Zhang Yanling
Published: October 2023

All-fiber acousto-optic tunable filters (AOTFs) have advantages of wide wavelength tuning range, fast tuning speed and low insertion loss. The resonance wavelength of the all-fiber AOTF can be tuned by adjusting the driving frequency of the piezoelectric transducer (PZT). In general, the driving voltage needs to be tuned in wide range in the wavelength tuning process, due to the existence of resonance frequency of the PZT. In this work, we propose and demonstrate a stability-enhanced all-fiber AOTF based on multi-PZT, which can reduce the dependence on the resonant frequency of a single PZT. In the experiment, the acousto-optic coupling efficiency can maintain larger than 80%, when the resonance wavelength of the AOTF is tuned from 1400 nm to 1600 nm, under the condition of a fixed driving voltage. The high tuning stability of the proposed multi-piezoelectric driving configuration can facilitate the practical applications of the all-fiber AOTF, such as the laser wavelength tuning, wavelength-division-multiplexing optical communication, fast optical spectroscopy, and so on.
Efficient two-dimensional Fraunhofer diffraction pattern via electron spin coherence
Authors: Meddour H , Askar Sh , Dehraj S , Al-dolaimy F , Abdullaeva B S , Alsaalamy A , Fenjan M N , Alawadi A , Kareem S H , Thabit D
Published: October 2023

In this letter, we have discussed the two-dimensional diffraction pattern via electron spin coherence in a GaAs quantum dot. Impulsive stimulated Raman excitation utilizing coherent optical fields is employed for the purpose of regulating the electron spin coherence within a charged ensemble of GaAs quantum dots, by means of an intermediate charged exciton (trion) state. We show that for the coupling two-dimensional standing wave (SW) field in the x and y directions, the two-dimensional Fraunhofer pattern can be formed for a weak probe light. By using the experimental parameters and controlling the Rabi frequency of the SW field and relative phase between applied lights, the symmetry and asymmetry diffraction pattern are obtained for the weak probe light due to the four-wave mixing mechanism. Our proposed model may have potential applications in high-capacity optical communications and quantum information technologies.
Low-power red laser and blue LED on circadian gene mRNA levels in human breast cancer cells
Authors: Ribeiro Rickson Souza , Rodrigues Juliana Alves , dos Santos Soares Márcia , Mencalha Andre Luiz , de Souza da Fonseca Adenilson
Published: October 2023

Low-power blue light-emitting diode (LED) and red laser have been used for therapeutic proposals based on photobiomodulation (PBM). This effect is trigged after absorption of radiation by photoacceptors, which lead to molecular, cellular and systemic responses. Cryptochromes are involved in circadian cycle control, and associated with development and progression of tumors. Despite such proteins are able to absorb violet-blue lights, there are few data on their participation in PBM. Thus, this work aims to evaluate the effects of radiations emitted by low-power blue LED (470 nm) and red laser (658 nm) on mRNA levels from cryptochromes genes as well as those from involved in their regulation in human breast cancer cells. The MCF-7 and MDA-MB-231 cells were exposed to low-power blue LED (470 nm, 640 J cm−2) and red laser (660 nm, 9 J cm−2), and relative mRNA levels from CRY1, CRY2, PER2, BMAL1 and CLOCK genes were evaluated by reverse transcription-quantitative polymerase chain reaction. The results suggested that exposure to low-power blue LED and red laser do not alter the mRNA levels from cryptochromes genes, and those involved in their regulation, in MCF-7 and MDA-MB-231 human breast cancer cells.
A novel radiometric calibration of an infrared thermometer
Authors: Yamada Yoshiro , Harris Subrena , Theocharous Evangelos , Hayes Michael
Published: October 2023

A new temperature calibration scheme was proposed and implemented on the National Physical Laboratory infrared radiometer Absolute Measurements of Blackbody Emitted Radiance (AMBER) operating in the wavelength range from 9 µm to 11 µm and equipped with a cryogenically cooled mercury cadmium telluride detector. The scheme involves measurements of the relative spectral responsivity of the filter radiometer including the spectral transmittance of the window and lens. It requires calibration at two reference temperatures, but does not involve measurement of the zero-radiance signal. The scheme uses a Ga-point blackbody as one reference point, and a variable temperature blackbody source at close to −30 °C with its temperature measured with a standard platinum resistance thermometer as the other. The measured temperature was compared using the variable temperature blackbody as the source against the temperature measured by the standard platinum resistance thermometer and agreement within the uncertainties was confirmed at intermediate temperatures. The scheme has the advantage that it makes full use of the small uncertainty realised by the fixed-point blackbody. The scheme was successfully implemented in an international comparison of sea surface temperature measuring radiometers where AMBER served to provide the reference.
Saturated cavity ringdown spectroscopy at Balmer-α line
of atomic hydrogen for estimating sheath electric field in plasma
Authors: Fushimi Kimika , Nishiyama Shusuke , Tomioka Satoshi , Sasaki Koichi
Published: October 2023

We applied saturated cavity ringdown spectroscopy (CRDS) to the measurement of the
Doppler-free absorption spectrum of the Balmer-α line of atomic hydrogen in an inductively
coupled hydrogen plasma. The spectrum was used for estimating the electric field in the sheath
region in the vicinity to a biased electrode. The absorption frequency (the absorption
coefficient multiplied by the speed of light) and the saturation parameter were estimated by
fitting the experimental ringdown curve with the theory reported by Giusfredi and coworkers
(Phys. Rev. Lett.
104 (2010) 110801). We detected the Lamb dip corresponding to the
2p
2
P
o
3/2 - 3d
2
D
5/2 transition in the absorption spectrum in the field-free
condition. We observed the change in the Lamb dip spectrum when we repeated the measurement in
the sheath, and we succeeded in estimating the sheath electric field of 220–230 V/cm at a distance
of 1.8 mm from the electrode which was biased at -100 V with respect to the ground potential. The
experimental results indicate the potential of saturated CRDS for the measurement of sheath
electric fields in plasmas.
A novel Hirota bilinear approach to N = 2 supersymmetric equations
Authors: Delisle Laurent
Published: October 2023

This article presents a novel application of the Hirota bilinear formalism to the N = 2 supersymmetric Korteweg–de Vries and Burgers equations. This new approach avoids splitting N = 2 equations into two N = 1 equations. We use the super Bell polynomials to obtain bilinear representations and present multi-soliton solutions.
Nonlinear Mori–Zwanzig theory and quadratic coarse-grained coordinates for complex molecular systems
Authors: Martzel Nicolas
Published: October 2023

We first introduce the Zwanzig–Kawasaki version of the generalized Langevin equation and show as a preamble and under some hypothesis about the relaxation of the fluctuations in the orthogonal subspace, that the commonly used term for the Markovian approximation of the dissipation is rigorously vanishing, necessitating the use of the next-order term, in an integral series we introduce. Independently, we provide thereafter a comprehensive description of complex coarse-grained molecules which, in addition to the classical positions and momenta of their centers of mass, encompasses their shapes, angular momenta and internal energies. The dynamics of these quantities is then derived as the coarse-grained forces, torques, microscopic stresses, energy transfers, from the coarse-grained potential built with their Berne-like anisotropic interactions. By incorporating exhaustively the quadratic combinations of the atomic degrees of freedom, this novel approach enriches considerably the dynamics at the coarse-grained level and could serve as a foundation for developing numerical models more holistic and accurate than dissipative particle dynamics for the simulation of complex molecular systems. This advancement opens up new possibilities for understanding and predicting the behavior of such systems in various scientific and engineering applications.
The marine fossils and paleoecological significance of the Southern edge of South Sumatra Basin in Linggapura Lampung, Indonesia
Authors: Harbowo D G , Pratama D , Priadi B , Julian T , Sihombing D J P , Sitinjak E S
Published: October 2023

The South Sumatra Basin is identified as a Paleogene-Neogene sedimentary basin with Mesozoic basements. It is located in the eastern Barisan Mountains, covering Jambi, South Sumatra, and Linggapura (Lampung), Indonesia. Linggapura represents the southernmost part of the South Sumatra Basin. The basin consists of two well-known rock formations, namely the Talangakar and Baturaja Formations. In this study, we investigated these formations through fossil records and paleoecological interpretations. Our investigation was based on measured stratigraphy and fossil observations along the Way Penandingan River in Linggapura, Lampung. We discovered that the bottom of this area consists of Cretaceous granitoid, which forms a nonconformity with the sedimentary rocks in this area. The Talangakar Formation in this region comprises quartzy-grained sandstone and conglomerates containing fossilized remains of terrestrial plants/vegetation. These plant fossils have undergone coalification, with some being silicified. The Batujara Formation in Linggapura is dominated by bioclasts, primarily consisting of Miocene shoreface-lagoonal larger benthic foraminifera, along with other marine and ichnofossils. Based on our findings, we suggest that the paleoecological condition of this area is associated with shoreline transgression during the Oligo-Miocene period. The hotter Miocene climate contributed to a rise in sea levels, resulting in shoreline transgression. Gradually, the area transformed from a terrestrial environment to a highly bioproductive marine environment, at least from the Late Oligocene to the Early Miocene. This study represents an important milestone in better understanding the paleoenvironmental conditions at the edge of the South Sumatra Basin throughout its geological history.
Identification and Characterization of Gas Hydrate using Marine Seismic and Well Data: South Makassar Strait case study
Authors: Muntashir A W , Nainggolan T B , Supriyana E
Published: October 2023

Gas hydrate has the potential as an alternative unconventional resource to current oil and gas. Identification of gas hydrate is made possible by applying the seismic method with the main indicator of the bottom simulating reflector (BSR). BSR is characterized on the seismic section by the presence of high amplitudes, reverse polarity reflections, and cutting through the stratigraphy. In this study, the presence and thickness of the gas hydrate zone have been identified using five 2D seismic tracks, namely CM02-57, SM93-06 SM93-08, SM93-09 and SM93-11, and the SULTAN-1 well. The gas hydrate zone was identified at a depth of about 2300 m. The existence of the gas hydrate zone is followed by the presence of a gas chimney indicator as a free gas migration path. The gas hydrate zones are estimated to be 15 m, 28 m, 33 m, 23 m, and 30 m thick from the respective seismic tracks CM02-57, SM93-06 SM93-08, SM93-09 and SM93-11.
Carbon Emissions Prediction from Land Change Model in Bandung Regency, Indonesia
Authors: Indrarini I , Handiani D N
Published: October 2023

Carbon emissions in Bandung Regency is potentially increasing and can harm future environment in the area. Our study aims to predict carbon emissions in Bandung Regency based on land changes model of the area. We utilized Cellular Automata Markov method which predicted land use in the years of 2027 and 2036. This land use prediction used overlay intersect method and were analysed using two scenarios: backward and forward looking. The backward looking scenario analysis combined the land used map of 2019 and two land use maps prediction of 2027 and 2036. Meanwhile, the forward looking scenario analysis combined the land used map of 2019 and the urban planning plan of Bandung Regency in the years of 2016 to 2036. Carbon emission were calculate using stock difference method for both scenarios. Afterwards, the carbon emission results were classified using quartile method. The result in the backward scenario showed that the carbon emission is dominated compare to sequestration, with total emission of 811,330.81 tonnes of CO2
eq for the years of 2019 to 2027 and 998,288.22 tonnes of CO2
eq for the years of 2019 to 2036. In the forward looking scenario, carbon sequestration is dominated compare to emission, with highest sequestration around -804,125.22 tonnes of CO2
eq, while highest emission is around 245,506.51 tonnes CO2
eq. Overall, both simulation showed that the highest emission occurs in Cilengkrang-Cimenyan development area, and the carbon sequestration occurs in Baleendah, Cileunyi-Rancaekek, and Margahayu-Margaasih development areas.
Identification of Landslides Controlling and Triggering Factors using the Analytical Hierarchy Process (AHP) in Dermasuci Village, Pangkah District, Tegal Regency, Central Java Province - Indonesia
Authors: Widodo B T , Setiawan H , Warmada I W
Published: October 2023

The National Disaster Management Agency (BNPB) stated that in 2022 around 634 landslides occurred in Indonesia. One of the regions in Indonesia that experienced landslide disasters is Dermasuci Village, Pangkah District, Tegal Regency, Central Java Province. The first landslide disaster occurred on February 5, 2022, and the second landslide occurred on February 10, 2022. The landslide disasters caused damage to 61 residents’ houses and four road sections. The objective of this study is to identify the controlling and triggering factors that mainly contributed to the landslide event. These two factors are determined based on the order of their static and dynamic properties using the analytical hierarchy process (AHP) method. Controlling and triggering factors of the landslide in the study area are determined based on geological and engineering geological conditions which were obtained from surface mapping results. The controlling factors obtained are the rock bedding inclination, geological structure in the form of faults, slope inclination, engineering properties of soil and rock, land use, and groundwater table. The triggering factors that are known and commonly occur are rainfall in the form of antecedents and intensity, and earthquakes that can induce landslides.
Geochemical characteristics of lacustrine source rock: An insight of Banuwati Formation from Sunda and Asri Basins, Indonesia
Authors: Priyanto Bagus , Subroto Eddy Ariyono , Kesumajana Asep Heri Patria , Susanto Very , Suryanto Agus Dwi
Published: October 2023

The Sunda and Asri Basins are petroliferous in Indonesia. Despite producing billions of barrels of oil equivalent since their initial production, research on the source rock organic geochemistry of these basins remains limited, particularly concerning the sapropelic kerogen of the syn-rift Banuwati Formation. A comprehensive study of the Banuwati Formation in the Sunda and Asri Basins was conducted using kerogen and biomarker data. Various techniques, such as carbon analysis, Rock-Eval pyrolisis, vitrinite reflectance (Ro), gas chromatography (GC), and gas chromatography-mass spectrometry (GC-MS), were employed on samples from six wells. The Banuwati Formation exhibits source rock with good to very good quantities. Biomarker analysis offers a novel interpretation, suggesting that the Banuwati shale source rock was deposited in an oxic-suboxic environment. The formation is primarily composed of Type I organic material, characterized by the presence of biomarkers such as C26 tricyclic terpane, C30 4-methylsterane, and a possible botryococcane peak, indicative of a lacustrine setting. Maturity assessments based on Ro and Tmax values show conflicting results. Tmax values imply maturity, while Ro values suggest immaturity. This discrepancy is likely due to Ro suppression, a phenomenon often observed in Type I kerogen samples.
Application of modified Segment Tracing Algorithm (mSTA) Method to Identify Landslide Susceptibility Zones Around Mt. Sinabung, Indonesia
Authors: Zahratunnisa  , Saepuloh Asep , Kriswati Estu , Basuki Ahmad
Published: October 2023

Lineament could present the fractured zones and increase the landslides occurrence probabilities. This study aims to assess landslides susceptibility zones based on recorded landslide events corresponded to the detected lineaments around Mt. Sinabung, Indonesia. In this study, we use Synthetic Aperture Radar (SAR) data to increase the extraction accuracy of fracture-related lineament at Mt. Sinabung. The lineament densities were calculated to identify the landslide susceptibility zones including frequency, length, and intersection using modified Segment Tracing Algorithm (mSTA) method for area about 10.9 × 9 km. Based on visual observations and technical report, a total of 61 landslides were occurred around Mt. Sinabung from 2016, 2018, and 2021. An Ordinary Kriging density map of the lineament frequency using 800 × 800 m cells showed agreement between the lineament density and landslide distribution. Comparing landslide location and lineament density, landslide occurrences were located mainly at high and moderate lineament densities. We have classified the landslide density for three years into low, moderate, and high based on histogram quartile analyses. This classification could be used to mitigate the landslide hazard in a large area.
Assessing Geotourism Aspects of Ungaran Geothermal Areas for Promoting Sustainable Energy through Volcano-Geothermal Tourist Destination
Authors: Marin J , Paskarana A , Sandy E B S , Agustian J
Published: October 2023

The indigenous nature of the Ungaran volcano-geothermal area allows us to bring the benefit to its nearest community. Geotourism can be an opportunity to introduce geological knowledge and foster the socio-cultural acceptance of society towards geothermal. This study aims to assess the potential of the study area as tourist destination. The research method is collecting data on geothermal manifestations and volcanic feature sites, quantitative assessment of geosites and geomorphosites, and preliminary hazard risk analysis. Study results identify six geosites: Gedong Songo area, Nglimut hot spring, Diwak-Derekan-Kaliulo warm spring, and Mawar camping area which features a volcanic landscape. Five of six geosites have high geotourism value of more than 0.5 in average, except for Kaliulo site. The recommendation of activities to do are leisure activities in nature, hiking, camping, thermal bathing, horseback riding, and geological excursion.Ttourists should be cautious of potential hazards risk from volcanic gases, hot and acid waters, slippery and unstable areas, landslides, rugged terrain, and extreme weather. A geotourism model is constructed to highlight each site and their attributes to Ungaran volcano-geothermal setting, tourism activities, and possible risks. By exploring the natural and geological richness offered by this destination, tourists will discover the uniqueness of volcano-geothermal tourism experience.
Surface Geology Analysis on the Relationship between Fault Creep and Overpressure in Grobogan, Central Java, Indonesia
Authors: Sitinjak Eri S. , Sapiie Benyamin , Ramdhan Agus M. , Hidayati Ana N. , Azhari Yanuar A. , Adriyansyah Nanda F.
Published: October 2023

The Grobogan Regency is a significant location for oil and gas exploration due to its proximity to active oil and gas fields. Geologically, this area is intersected by the Kendeng thrust fault and exhibits several surface manifestations of mud volcanoes near the fault. However, there have been limited studies examining the activity of the Kendeng thrust fault and its relationship to overpressure and earthquakes, which could affect oil and gas exploration and natural disaster mitigation in the region. This paper focuses on utilizing surface geological mapping data and Interferometric Synthetic Aperture Radar (InSAR) data to analyze the relationship between fault creep and overpressure manifestations in Grobogan, Central Java. While continuous research on fault creep has been conducted since the 1960s on the San Andreas fault in the United States, there has been a lack of continuous research on onshore fault creep in the Northeast Java Basin or Kendeng Basin, particularly in the Grobogan area. This region, known for its abundance of active mud volcano manifestations, is predominantly characterized by marl and clay lithology. It represents a warm basin environment that is prone to overpressure and ideal for fault creep occurrences.To investigate further, fluid, gas, and mud samples were collected from the mud volcanoes, along with rock samples from the surrounding area, for comprehensive laboratory analysis. The integration of these sample analyses aimed to determine the correlation between the activity of the Kendeng thrust fault creep and the subsurface overpressure conditions. While this study observed several indications of creeping in the vicinity of InSAR anomalies, the exact location of the creeping fault plane could not be definitively determined. The Kendeng thrust fault exhibits the three main factors necessary for initiating fault creeping. The fault segment’s extremely slow creeping may be linked to the activity of the mud volcanoes, as indicated by the results of fluid, gas, and rock sample analysis. The findings of this research hold potential for informing the development of oil and gas fields, as well as enhancing the mitigation of natural disasters associated with oil and gas exploration and earthquakes in the region.
Velocity Changes Associated to the 2019 Ambon 6.5 Mw Earthquake Using Ambient Seismic Noise
Authors: Amiruddin A , Puspito N T , Sahara D P , Nugraha A D , Zulfakriza
Published: October 2023

Seismic velocity changes which occurred before, during and after large magnitude earthquake carry information about damage fault surrounding the area. Research focused on Ambon 6.5 Mw earthquake on September 26, 2019. We use ambient noise cross-correlation technique to compute empirical Green’s Function between station pairs from January to December 2019. We use doublet method to determine perturbation calculated in frequency domain by using Moving Windows Cross Spectrum in frequency between 0.1 to 1.0 Hz. Our results show no obvious significant velocity change before the mainshock. Velocity fluctuation average about ±0.1% caused by non-isotropic of noise source around the area. Sudden velocity decrease occurred and reached average value of -0.35% in 7 days after mainshock. After reaching its lowest value, velocity gradually increased about +0.4% in 14 days. Velocity fluctuations about ±0.2% also occurred for three months after the earthquake which may caused by the aftershocks around the earthquake epicentre. Following the large magnitude mainshock, velocity reduction may be induced by cracks opening and fractures due to deformation. While the velocity increase may caused by post-seismic relaxation due to elastic behaviour and crack healing of the fault throughout the surrounding region.
Geochemical and geological properties of tin related to ore deposits: A Review
Authors: Handoko A D , Sapiie B , Syafrizal  , Rudyawan A
Published: October 2023

Tin have atomic number 50 and atomic mass 118,71, commonly found as cassiterite in nature. It is one of important elements in low carbon technologies. Nowadays, tin utilized in broad application range from tin can to electronics. Despite many uses, tin is only produced from limited areas. Because of broad application, understanding of tin in nature is important. Tin usually can be found together with wolfram, although it often occurs at different locations. Tin may occur in various ore deposit types such as greisen, vein, skarn, and placer. This article will describe the geochemical and geological properties of tin in nature, especially that related to ore deposits.
Design and Preliminary Results of Debris Flow Analog Model in Laboratory Scale, Case Study of Bentarsari Sub-watershed
Authors: Sadisun Imam A. , Dinata Indra A. , Hutasoit Lambok M.
Published: October 2023

Bentarsari sub-watershed is located at Brebes Regency administrative area, Central Java. This sub-watershed is surrounded by hills composed by volcanic breccia of Kumbang Formation (Tpk) and consists of sedimentary rocks at the lower part of the watershed. Volcanic breccia is the oldest rock in the watershed and appears to have a more intensive weathering process, making it more susceptible to landslides which are mostly followed by debris flow. Accordingly, the aim of this research is to conduct a laboratory scale analog modeling of debris flow event in this sub-watershed. The main materials used for modeling are moderate to completely weathered volcanic breccias to residual soils. The rainfall scenario is 50 mm/day as lower bound of heavy rain, 100 mm/day as lower bound of very heavy rain and 150 mm/day as lower bound of extreme rain. As a first step, the computer simulation is used for analyzing material movement of the model, using spherical materials with a density of 1.84 g/cm3 taken from average value of laboratory test results. The simplification process is carried out on spherical material with 4 cm and 2 cm diameter to depict moving material. The solid material volume used in the simulation is 0.07 m3 while the liquid is 0.03 m3. Then, a laboratory scale analog model has been made with a tub having dimensions of 0.5 m high, 2 m long and 1 m wide. When this analog model is tilted 50 degrees, the resulting slip plane then extends to the backward of the slope and the flowing materials move downward colliding with the previously deposited material, forming a flow which bends slightly to the left at the foot slope. The results of this research are expected to lead to a new method for modelling debris flows using analog models at laboratory scale.
First occurrence of planktonic foraminiferal species Boliella adamsii as a marker for the Pleistocene-Holocene Boundary in the sea around Sumba Island
Authors: Ardi R D W , Aswan  , Maryunani K A , Yulianto E , Putra P S , Nugroho S H
Published: October 2023

The expensive cost of Accelerator Mass Spectrometry radiocarbon dating (AMS 14C), the main tool for geochronology in Late Pleistocene-Holocene paleoclimate and paleoceanography study using marine sediment cores, hinders Indonesian researchers to produce competing research outputs. The first occurrences of planktonic foraminiferal species which have been applied as Pleistocene-Holocene Boundary markers in previous Quarternary marine sediment studies in the Indonesian region need to be confirmed as these species might actually occur since the Late Pleistocene. Quantitative foraminifera determination and oxygen isotope (δ18O) analysis of planktonic foraminiferal species Globigerinoides (Gs.) ruber have been carried out in marine sediment cores ST10 (off south Sumba) and ST14 (Sumba strait). δ18O of Gs. ruber was correlated to North Greenland Ice Core Project (NGRIP) Greenland Ice Core Chronology 2005 (GICC05) δ18O to determine the depth of the Pleistocene-Holocene Boundary (11653 BP) in core ST10 and ST14. Pleistocene-Holocene Boundary depth in core ST10 (31 cm) and ST14 (28 cm) are nearly coeval with the First occurrence (FO) of planktonic foraminifera Boliella adamsii, which at 34-35 cm depth interval in core ST10 and at 26-27 cm depth interval in core ST14. This indicated the practicality of Boliella adamsii FO as a Pleistocene-Holocene Boundary marker in the sea around Sumba Island, in case radiocarbon ages and proper planktonic foraminiferal δ18O data are not available. Future studies using a similar method in other Indonesian regions are needed to confirm the practicality of Boliella adamsii FO as a Pleistocene-Holocene Boundary marker in the Indonesian region.
Characterizing Coastline and Sediment Interaction in The North Coast of Java using Satellite Images
Authors: Nainggolan Efrat N. , Saepuloh Asep , Nurdjaman Susanna
Published: October 2023

The large amount of sedimentation process caused rapid changes in the coastline presented by capes form in the coastal area. To characterize coastline and sediment interaction used coastline change analysis, hydrological and vegetation indices using Landsat imagery. Accordingly, we successfully characterized the Cirebon coastline into four categories: abrasion, accretion, abrasion to accretion, accretion to abrasion. The NSM range values -1.123,67 m – 1.026,19 m. The highest abrasion (EPR, LRR, WLR) is 33,18 m/y, 31,16 m/y and 31,16 m/y. The highest accretion (EPR, LRR, WLR) 30,3 m/y, 29,16 m/y, 29,16 m/y. The results of the hydrological index parameters show that humidity levels vary from drought (low humidity) to high humidity, but in the eastern part it includes the water surface. The results of the vegetation index parameter show that the vegetation level was dense, moderate to sparsely grown with vegetation, canopy cover varying from low to medium. Clay material (mud) has impermeable properties, so the study area is dominated by accretion because there is large supply sediment from rivers that enter the sea. Based on these data, it can be concluded that the characteristics of the beach are divided into muddy beaches, and coastal structures such as harbor.
Evaluation of GNSS reflectometry method for sea level estimation in Indonesia
Authors: Cahyaningtyas Lisa A. , Wijaya Dudy D. , Setyadji Bambang , Kartadikaria Aditya R. , Park Hansan , Wibowo Sidik T. , Himawan Rega
Published: October 2023

Over the last decade, GNSS-R (Global Navigation Satellite System reflectometry) has emerged as a technique for observing sea level height using data from GNSS observations. GNSS-R estimates sea level height from the phase center antenna using the reflection of the extracted GNSS signal at sea level. With a large number of tidal stations equipped with GNSS antennas, GNSS-R has the potential to be implemented in Indonesia. GNSS-R observations can also cover sea surface areas tens to hundreds of kilometres away from where the antenna is located over the coast. Furthermore, the installation of a GNSS antenna at a safe height on land allows for the observation of sea levels under extreme conditions such as during storms and cyclones. To employ GNSS-R effectively, several factors must be considered, including signal-to-noise ratio (SNR) data analysis, data processing, filtering control variables, and increased frequency extraction. This study will focus on trying to use GNSS-R method by identifying the best control variables for each study area and evaluating the results. This study used three months of GPS and GLONASS satellite SNR data from two stations, Barus and Morotai. The separated multipath data was then analyzed using the Lomb-Scargle Periodogram (LSP) based on its frequency. The results of GNSS-R sea surface height observations were validated using tide gauge data at both stations. Based on the test results, the RMSE values were 8.7 cm and 8.4 cm at Barus and Morotai stations, respectively. GNSS-R results strongly correlate with tide gauge data, with correlation coefficients of 95% and 98% at Barus and Morotai stations, respectively. Based on these findings, the GNSS-R method can be used to complement tidal sensor data by applying proper quality control.
Variation in sediment characteristics between canopy gap and surrounding forest in Can Gio Mangrove Biosphere Reserve, Vietnam
Authors: Pham H Q , Hoang K T , Bui A T , Le S T
Published: October 2023

This study presented the difference in the sediments under a large gap formed by the Durian typhoon in 2006 and its surrounding intact forest in Can Gio Mangrove Biosphere Reserve, Vietnam. Twelve plots previously settled in the original gap and its surrounding forest were used to collect sediments in the dry and wet season in 2019 to assess the difference in sediment properties and nutritional state caused by the self-recovery of the vegetation. Sediment temperature and pH were measured in field, while the contents of total organic carbon (Corg) and total nitrogen (Ntot) were subsequently quantified in the chemical laboratory. Sediment temperature, salinity, and pH between the gap and the surrounding forest were not statistically different. The variation of Corg concentration in the gap sediments seemingly increased with depth from 1–15 cm in the dry season. The Ntot in the gap sediments showed that it was continuously consumed in the underlying sediments during both seasons. In conclusion, the variation in vegetation composition between the gap and its surrounding forest was responsible for the differences in sediment C and N concentrations.
Vegetation Indices for Spatio-Temporal Analysis of the Quality of Can Gio Mangrove for Biodiversity and Conservation
Authors: Nguyen T P C , Le T H , Nguyen T O , Le C L , Ha T C
Published: October 2023

Mangrove forest has an important role in protection against coastal erosion and carbon dioxide sequestration for climate change mitigation. The natural increase in vegetation quality can explain the increase in its health and biodiversity. This study aimed to examine the health of Can Gio Mangrove vegetation to determine its potential for preventing coastal erosion and maintaining biosphere’s conservation function. Algorithms in GIS and remote sensing were used along with the time-series temporal Landsat images in the 2010-2020 period to investigate the changes of vegetation indices: Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Leaf Area Index (LAI), and Normalized Difference Water Index (NDWI). The results showed positive changes of vegetation values between dry season and rain season, and large distribution of their good values in the 2010-2020 period. Decrease in the vegetation area and stability of surface waters area indicate the expansion of urbanized area. These results may support modification of the policy to control the urbanization, to maintain the mangrove biosphere reserve, and to enhance coastline stabilization.
Vulnerability Assessment of the Upper-Middle Pleistocene (qp2-3) Aquifer in Ho Chi Minh City, Vietnam Using GIS and Expanded DRASTIC Methods
Authors: Nguyen A H , Tat V M H , Vo P L
Published: October 2023

The groundwater vulnerability assessment model (DRASTIC) for zoning sensitivity based on natural and objective factors of aquifers is currently used and applied widely. In this study, we have expanded the weights in the DRASTIC index through the Entropy weight-based technique and visualized them in association with GIS for assessing the vulnerability of the Upper-Middle Pleistocene aquifer in Ho Chi Minh City, Vietnam. The value of Entropy weights calculated from the collected dataset of 106 monitoring boreholes of the study area. The Entropy-DRASTIC results divided into three categories: 9.45% of the study area was in the high vulnerability zones, low and medium vulnerability zones are 21.5% and 69.05% of the total study area, respectively. The highly vulnerable area, which is shallow aquifer roofs and recharged significantly (directly from rains or runoff from the surface flows exposed to contaminants from runoff flows). Low vulnerability areas with clay cover are weak permeability and medium vulnerability area is a sizable transitional zone surrounding the high and low vulnerability. This result suggests that the DRASTIC index model in association with GIS is a useful tool to assist policymakers in formulating solutions for the use of groundwater resources. Importantly, this finding is useful to the local authorities in shaping regulations on the use and exploitation of groundwater resources in suburban areas, where the public water supply network is inadequate, constrained groundwater resource and exposed to contamination.
The South Seas and Islands in Vietnam’s Maritime Strategy: Position and Development Potential
Authors: Quyet L V , Sen V V , Tien T A
Published: October 2023

Over 1,000 kilometers of islands and archipelagos make up Vietnam’s southern coastline. The following points are emphasized in the article based on surveys and secondary sources: (1) the benefits of the Southern Sea and Islands’ geographic location, environmental conditions, and natural resources; (2) the Southern Sea and Islands’ role in Vietnam’s marine economic development strategy; and (3) approaches to the sustainable development of the Southern Sea and Islands in Vietnam’s overall marine and island development strategy. The findings of the study indicate that the Southern Sea and Islands have abundant and diverse potential in terms of energy, maritime transport, ecosystems, and tourism, serving as a critical location for national security and defense for the region and the whole country. The development of marine and island values in the southern region of the country is a key component of Vietnam’s marine economic development strategy, which also emphasizes harmonious growth. Focusing on synchronized and harmonious actions is essential in the process of taking advantage of the Southern Sea and Islands’ benefits for the process of global economic integration. It is also important to promote the involvement of numerous economic sectors in the process of utilizing and sustainably growing the marine economy.