bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Cross-hole Seismic Tomography to Inferred Cavities Condition.
Authors: Fatkhan  , Ryannugroho Riskiray , Lawrens Fernando , Delliansyah Rendy , Prabowo Billy Sugiartono , Sule Mohammad Rachmat 
Published: September 2023

Abstract
The construction of the Rajamandala hydroelectric power plant civil works has experienced critical problems that arise in the implementation process, with the occurrence of cracks cavities conditions in the headrace tunnel locations. We applied the cross-hole seismic tomography to detect important heterogeneities and mechanical proprieties of the formations between two boreholes in this case inferred cracks cavities condition. The seismic source is inside the borehole “a sparker” and the receivers “hydrophones” are in an adjacent one, the sparker is lowered into the borehole one step at the time. Seismic waves, propagating in the tunnel wall rock, spread widely, and are reflected and refracted when encountering interfaces between rocks with different acoustic impedances. Reflected waves returning to the receivers are recorded. After the processing of the first arrivals of the P waves we obtain a cross section of the seismic velocities in between the two wellbores. With the cross-hole seismic tomography, the basis could be provided to the tunnel construction and parameter adjustments to guarantee the construction safety. Our result shown that there is a weak zone above the tunnel with low Vp zone (~1.2 km/s) may be related to weak zone (may be fracture, unconsolidated rock, and fluid-filled rock or landslide caving). Checker-board resolution test is also conducted to determine the tomogram areas that are reliable to be interpreted. Our challenges are we have poor resolution due to not enough raypath. The Cross-hole seismic tomography can effectively and safely guide the excavation of the tunnel section working surface in combination with reconstructed images and excavation technology.
An Attempt To Invert Tomography Delay Time Problem With Hybrid Lsqr
Authors: Rizkiyana A , Ajeng Belista N 
Published: September 2023

Abstract
Indonesia is situated in Southeast Asia’s active tectonic zone, influenced by the movement of four plates: the Eurasian Plate in the south, the Eurasian Plate in the north, the Philippine Plate, and the Pacific Plate in the northeast. The Tomography approach was used in this work to obtain a stable solution, which was achieved through regularization. Least Square and Hybrid Lsqr are the inversion methods employed. This research aimed to use the IR Tools Package Irhybrid LSQR to investigate inversion tomography with regulatory approaches in 3D. In this study, Matlab is used to perform inversion tomography. Two types of data, real and synthetic, are employed at this stage. The study’s genuine data came from earthquake catalogues from BMKG, MARAMEX, DOMERAPI, and BPPTKG, with depths ranging from 0-658 km and recorded between 20 December 2013 - 6 September 2020, with an area boundary of 110.1 – 110.8. LS -7.8–7.2 BT. The red colour represents the magma reservoir area according to the inversion data. Hybrid LSQR is an iterative approach that is considered stable enough to be used in tomography. When applied to tomographic coding and compared to the most widely used inversion method, Least Square, the results obtained in the least Square have a higher value than Hybrid LSQR.
2D and 3D modelling of Molucca Sea double subduction zone based on primary waves travel time seismic tomography inversion
Authors: Pratita G A N , Palupi I R , Prasetyadi C 
Published: September 2023

Abstract
Molucca Sea is one of the areas with a high level of seismicity in Indonesia due to its location between three plates. The activities of them forming a quite unique subduction zone. The Eurasian Plate (Sangihe Microplate) move to the East and The Philippine Sea Plate (Halmahera Microplate) continues to Westward caused The Molucca Sea Microplate to be pressed, and subducts in two opposite directions modelat the same time forming an inverted “U”. This research used 3663 hypocenters and 9 BMKG stations in the last 5 years (2016 - 2021) with a magnitude of 3 - 8 Mw and a depth of 3 - 630 kilometers. Seismic inversion of travel time tomography is used to produce 2D models of the subduction zone around The Molucca Sea. The distribution of high ΔVp values is ranging from 3.5% to 4% is associated with a solid medium, like The Sangihe Plate, Halmahera Plate, and The Molucca Sea Plate subduction slab. While the low ΔVp is ranging from 1.8% to 2% is associated with the destruction zone and the presence of thermal fluids such as magma or partial melting (the presence of volcanoes). The 3D model is based on the Gaussian Process Regression principle using magnitude and depth data as initial model parameters. Plotting of the thrust faults at the front of the two arcs, namely The West Sangihe Thrust Fault and The East Halmahera Thrust Fault. It can be seen that the subduction under The Sangihe Microplate is deeper (627.2 kilometers) has the average subduction angle of 45.3° compared to the subduction under The Halmahera Microplate (280.0 kilometers) has the average subduction angle of 35.8°
Early Modeling of Seismic Velocity Structure P, S, and Vp/Vs Ratio in Bengkulu Region and its Surroundings
Authors: Silaen N , Haqi Y A , Rochim D N , Firmansyah M F , Herawati I , Widyanti S 
Published: September 2023

Abstract
Bengkulu is located in the southern region of Sumatra, where the Indo-Australian and Eurasian plates are subducted. As a consequence of the subduction, seismicity in the area increases, as well as volcanic activity and the appearance of structures such as the Sumatran and the Mentawai faults. Seismic velocity structures were reconstructed using earthquake tomography in Bengkulu and the surrounding areas using data from the International Seismological Center (ISC) and the Meteorology, Climatology, and Geophysics Agency (BMKG). The earthquake data collection period was from January 1, 2010 to December 31, 2018. 19 stations recorded 1721 earthquakes. LOTOS-12 is used to do a tomography inversion, starting with a 1D velocity model and wadati’s Vp/Vs ratio and iteratively inverting for Vp, Vs, and Vp/Vs ratios. The bending algorithm is used to calculate the arrival time, and the LSQR method is used to invert it. The Checkerboard Resolution Test (CRT) yielded Tomography results. The results revealed the existence of zones with low-velocity anomalies and low-values of Vp/Vs ratios, indicating the presence of weak zones caused by Sumatra faults, Mentawai faults, and other local faults. Low-velocity anomalies with high-values of Vp/Vs ratios are related to volcanic activity, hereas high-velocity anomalies are associated with the existence of subduction plates and compact rocks. The low-velocity anomalies in the fore-arc at 30-50 km depths coincide with fluid circulation caused by slab dehydration.
Data Processing of Surface Wave Tomography in Australia using Automated Surface Wave Phase-Velocity Measuring System (ASWMS)
Authors: Saqina A , Kurniawan S , Yusami R , Abdullah A 
Published: September 2023

Abstract
The Australian continent is divided into tectonic blocks, including Archaean and Proterozoic units in the western and central part, and Phanerozoic units in the eastern part. Surface wave tomography is an effective method of getting information about velocity variations in a particular region. Surface wave tomography was used in this project to map the subsurface of the Australian continent down to a depth of 100 km with the ASWMS (Automated Surface-Wave Phase-Velocity Measuring System). From 2010 to 2015, we gathered waveform data from 767 events and 219 permanent and temporal seismic stations dispersed across Australia. We selected a set of events that has a minimum magnitude of 6. Rayleigh wave extraction and cross-correlation between two nearby stations are among the first processing processes. Following that, the apparent phase-velocity value is calculated using the Eikonal and tomographic inversion. To generate a tomographic map with a true structural phase velocity, each phase velocity data is stacked with amplitude correction. According to current tomographic imaging studies, low-velocity values under Australia tend to be dispersed easterly, with Rayleigh velocity ranging from 3.7 to 3.9 km/s. The tectonic history and evolution of eastern Australia are related to a sequence of orogenic events that are pushing toward the continent’s eastern boundary.
Geomagnetic Data Analysis to Identify Subsurface Condition of Gondang Area, Bojonegoro
Authors: Bohal Yolanda Mustika , Fermantono Ihsan , Mariyanto Mariyanto 
Published: September 2023

AbstractThe presence of manifestation in the Gondang indicates a specific geological condition. Those manifestations are Banyu Kuning Hot Spring, Selo Gajah Hot Spring, and Jari Mud Burst. The purpose of this study, which was carried out near Mount Pandan, was to identify the distribution of magnetic fields and magnetic anomalies, including the patterns of potential geothermal energy distribution in the region based on its magnetism. It also aimed to explain the rock structure in the manifestation area based on susceptibility values. The survey was conducted using 94 measuring points that were randomly distributed throughout the manifestation area. The data was corrected using IGRF and diurnal correction, and it was examined using Surfer 11 to construct a contour map and Oasis Montaj to visualize 3D models. According to the processed data, the residual anomaly’s value ranges from -232.1 nT until 159.4 nT. For the anomaly of residual, 2D and 3D models demonstrated low susceptibility dissemination values ranging from -0.029 until -0.0135 cgs on the manifestation zone. The high susceptibility value, which is considered an intrusion rock, has a value range of 0.011 to 0.046 cgs.
Rainwater Harvesting System (RWHS) for buildings: A mini review on guidelines and potential as alternative water supply in Malaysia
Authors: Juiani Siti Fairuz , Chang Chun Kiat , Leo Choe Peng , Goh Hui Weng , Ang Wei Lun , Aburamadan Rania Fayiz 
Published: September 2023

Abstract
Malaysia receives an abundance of rain annually (≈ 2400mm/year). The country, however, is not excused from water crises such as floods and water shortages. According to the National Water Services Commission (SPAN) data, Malaysia water consumption in year 2021 is 201 LCD and may encounter a water shortage crisis if the situation is not improved in the future. Rainwater harvesting (RWHS) has great potential in tackling water shortages. It can also combat water scarcity holistically and reduce dependency on treated water from dam reservoirs. RWHS is a sustainable alternative to tackle water crises with minimal environmental impact. Currently RWHS used for non-potable purposes like cleaning, toilet flushing, and irrigation. Due to the nature of the catchment area, there are several ways in which contaminants can enter the rainwater system and compromise the water quality. Elements such as topography, weather, and pollution sources, have a direct impact on the quality of rainwater that is collected and stored. In addition to the non-potable uses, RWH has been used for potable water in countries such as Australia and Bangladesh, but the total number of uses is still very small. For potable use, regular monitoring is required because it poses a health risk due to the presence of chemical, physical, and microbiological contaminants. If the water quality parameters meet the acceptable levels of water supply, harvested rainwater could be used for drinking purposes in many countries in the future. To ensure consistently good water quality, it is essential to establish standard operating procedures and maintenance schedules based on water safety plan approaches for both household and institutional users. This paper aims to review existing management guidelines and explore potential technologies for rainwater harvesting in buildings across Malaysia.
Sustainable thin shell analysis on structural foundation subjected to seismic loads
Authors: Nassir Azizah Abdul , Min Yee Hooi , Petchsasithon Arthit , Senin Syahrul Fithry 
Published: September 2023

Abstract
Shell structures are recognized for their exceptional performance in withstanding compression forces, often utilized as roof components. However, Southeast Asia experiences significant annual losses due to floods, with inadequate structural mitigation despite high population concentrations in seismic risk areas. Previous research explored thin shell structures as elevated foundations to mitigate flood effects on buildings. Unfortunately, the proposed shell design exceeded the material’s strength limit of 40N/mm2, limiting its feasibility. To address this, our study proposes a modified thin shell with a 600mm thickness. Finite Element analysis using LUSAS software evaluated the new design’s structural behavior under dynamic loads from earthquakes and flood-induced waves. Results demonstrate a substantial reduction of up to 99% in equivalent stress compared to the previous model [Model P]. The revised model [Model C] proves feasible in withstanding intense building loads, ensuring maximum stress remains below the concrete material’s strength limit. Implementation of these findings offers valuable structural mitigation, reducing flood impacts and enhancing both structural resilience and human safety.
Decision Making Toward Sustainable Material during Planning Stage at Construction in Seberang Perai Tengah Pulau Pinang
Authors: Musir Adhilla Ainun , Azlan Ahmad Faiz , Karim Nurulzatushima Abdul , Hassan Siti Hafizan , Nasir Siti Rashidah Mohd 
Published: September 2023

Abstract
The efficiency of using sustainable materials has been an important issue in ensuring the success of sustainable construction in Pulau Pinang. Unfortunately, the construction sector is one of the most energy-intensive sectors, contributing to global climate change and environmental issues. Thus, this study aims to identify the factor of sustainable materials selection in focusing on Seberang Perai Tengah and to determine the relationship between the decision-making factor and elements in the planning stage toward sustainable construction. The quantitative method was conducted by survey, and the instrument used was an online questionnaire survey. About 54 samples of the questionnaire were collected from those involved in the construction sector in Seberang Perai Tengah, Pulau Pinang. The result shows the factors of decision-making that have the most influence on sustainable material selection are technology and training. Meanwhile, the planning stage element that has the most significant influence on the criteria of sustainable material is the project life cycle. This study could be valuable for all parties in the construction industry, especially to the decision-maker, engineers, clients, employers and staff, academicians, policymakers, researchers, and organizations.
Potential development of organic Rankine cycle (ORC) power generation system by utilizing heat from natural hot-spring in Malaysia
Authors: Jasmi Ahmad Razin , Musa Nur Amalina , Zuber Muhammad Ahmar , Lazi Mohd Khairul Afzan Mohd , Omar Wan Zaidi Wan 
Published: September 2023

Abstract
Organic Rankine Cycle (ORC) is widely used because of its ability to work with low and medium-grade heat resources. ORC basically operate by using organic working fluid which allows the application of Rankine Cycle to be operate at various range of heat resources depend on the properties of working fluid. This allows wide application of ORC power cycle at temperature below 370 °C where the steam-based Rankine Cycle are no longer efficient. This present paper discusses the potential development of micro power generation based on the ORC concept by utilizing heat from natural hot spring in Malaysia. The performance of the systems is analysed based on three different working fluids which are R134a, R410a and R245-fa. The comparison was done by the variation of hot water inlet temperatures in the range of 50 °C to 75 °C at the evaporator and 25 °C of ambient water at the condenser. The results indicates that R245-fa had 9 % thermal efficiency when the hot water inlet temperature is 75 °C which is the highest among the other working fluids in the similar condition. Meanwhile, the ideal power output of turbine is also analysed. The R410 can generate 2.38 kW power output when the input temperature of hot water is 75 °C which is the highest as compared to other working fluid at similar condition. Therefore, it can conclude that the micro-scale power generation systems can be developed based on ORC power cycle by utilizing heat resources by natural hot spring in Malaysia.
A review of the effects of solar radiation management on hydrological extremes
Authors: Tew Yi Lin , Tan Mou Leong , Liew Juneng , Chang Chun Kiat , Muhamad Nurfashareena 
Published: September 2023

Abstract
Solar radiation management (SRM) is one of the proposed climate mitigation strategies to cool the planet rapidly. The injection of aerosol particles into the stratosphere for reflecting solar radiation back to the space is one of the SRM methods that are widely discussed. Theoretically, SRM might lower the earth’s temperature within a few months of deployment, reducing the impacts of climate change on natural disasters, i.e., floods and drought, which lead to huge losses in economic and human life. Solar radiation variability was identified to be a substantial factor that induced the hydrological changes, particularly in precipitation extreme. The effects of SRM on hydrological cycles, however, fluctuate depending on the location and environment. Hence, this article reviews the past SRM studies that related to the analysis of the hydrological cycle changes. A total of 17 articles were identified and collected from the Web of Science and Scopus databases. The results show that there have been an increasing number of articles in recent years studying the effects of SRM on the hydro-climatic changes. The Geoengineering Model Intercomparison Project (GeoMIP) and the Geoengineering Large Ensemble (GLENS) are two commonly used SRM-based general circulation models. In general, SRM is projected to slow down the global hydrological cycle. In comparison to the RCP 8.5 scenario, SRM generally tends to lower flood risk in many parts of the world. However, the majority of SRM research in hydrology has been conducted on a global scale, which results in a lack of robust basin-scale assessment needed for flood control policy formulation. In addition, more SRM climate models and scenario experiments should be considered to minimize the uncertainty in the framework for hydro-climatic modelling framework.
Preliminary survey on the root causes of mishandling materials occurrence at construction sites in central region Malaysia
Authors: Nadarason Kageishieny , Nagapan Sasitharan , Arumugam Niwashiny 
Published: September 2023

Abstract
A crucial issue has been perceived as construction waste generation, which negatively affects the effectiveness of construction project and its environmental impact. The key objective of the current research is to identify the root causes of mishandling materials at construction sites. A well-structured questionnaire was designed based on the 33 root causes of mishandling materials identified. The developed questionnaire was distributed to 28 highly experienced in Malaysian construction industry experts. The collected data was analysed by using mean score analysis. There are nine crucial root causes with a mean value greater than 3.70. The top identified root causes are lack of management commitments towards educating workers about safety, wrong handling of materials, lack of supervision, poor management, inappropriate storage leading to damage and mismanagement of materials. These initial findings will assist construction practitioners in addressing these root causes to reduce the material construction waste generated on construction sites.
Methods for increasing the energy efficiency of fan systems using wide-angle plane diffusers with splitter vanes
Authors: Klimentov Kliment , Popov Gencho , Kostov Boris , Kamenov Lachezar 
Published: September 2023

Abstract
Fan systems used to transport fluids are widely used and have become a major consumer of electrical energy worldwide. A significant part of the available energy of transported air in HVAC systems has usually been lost (in the form of dynamic pressure) at the system outlet. It is well-known that using outlet diffusers leads to this energy loss be reduced. In some cases, it is necessary to use shortened wide-angle diffusers, which have a higher coefficient of minor energy loss (local resistance). In the present work, a numerical study of the possibilities of increasing the energy efficiency of wide-angle plane diffusers, using splitter vanes, is accomplished. Diffusers with expansion angles of 30, 45 and 60 deg studied. The results obtained indicate the impact of the number of splitter vanes on the minor energy (local resistance) loss coefficient of the studied diffusers.
Development of minimalistic propulsion system for university nanosatellite
Authors: Baranova V S , Liashkevich S V , Saetchnikov V A 
Published: September 2023

Abstract
The paper presents the results of development of a neutralizer-free high-frequency ion thruster for university nanosatellite propulsion systems which allow it to perform orbit correction tasks. The application of high-frequency ion thruster technologies allows the self-neutralization mode and is relevant for the development of engines for CubeSat format small satellites where the size and weight of the propulsion system must be as minimal as possible. A pair of shapes of neutralizer-free high-frequency ion thrusters with different accelerating region geometries are proposed. The analysis of plasma flow and the charged particles acceleration was carried out. The trajectory and acceleration of a quasi-neutral plasma flow was calculated for crossed electric and magnetic fields. The cyclotron resonance model was applied for the quasi-neutral plasma flow acceleration in an ambipolar field. The coaxial structure of the ion thruster model is discussed. Preliminary estimate of the performance of the propulsion system prototype was carried out for a pulsed operation mode. Additionally, the energy budget of a high-frequency ion thruster prototype was calculated.
Exergy analysis, coupled heat pump and refrigeration system using waste heat
Authors: Dima D , Dobrovicescu A 
Published: September 2023

Abstract
The paper seeks the optimal configuration of equipment capable of generating heat and cold. For the generation of the two products, for the first time it is considered a coupled system heat pump and refrigeration system. Waste heat from an industrial process is used as the heat source for the heat pump cycle. For the refrigeration system, carbon dioxide is used as the working agent, and for the heat pump the working agent R152a. In order to identify the malfunctions at the level of each device and process, an exergy analysis is used, which identifies the magnitude and location of each malfunction. Based on the information provided by the exergy analysis, it is considered a structural optimization strategy by applying sub-cooling to the refrigeration cycle and heat pump cycle. The analysis shows an increase in the performance indices COPen and COPex when applying the subcooling at the level of the refrigeration cycle. The results of the exergy analysis make it possible to find solutions for improving the functional structure and design of equipment.