bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimizing the combination of data-driven and model-based elements in hybrid reservoir computing
Authors: Duncan Dennis , Räth Christoph
Published: October 2023

Hybrid reservoir computing combines purely data-driven machine learning predictions with a physical model to improve the forecasting of complex systems. In this study, we investigate in detail the predictive capabilities of three different architectures for hybrid reservoir computing: the input hybrid (IH), output hybrid (OH), and full hybrid (FH), which combines IH and OH. By using nine different three-dimensional chaotic model systems and the high-dimensional spatiotemporal chaotic Kuramoto–Sivashinsky system, we demonstrate that all hybrid reservoir computing approaches significantly improve the prediction results, provided that the model is sufficiently accurate. For accurate models, we find that the OH and FH results are equivalent and significantly outperform the IH results, especially for smaller reservoir sizes. For totally inaccurate models, the predictive capabilities of IH and FH may decrease drastically, while the OH architecture remains as accurate as the purely data-driven results. Furthermore, OH allows for the separation of the reservoir and the model contributions to the output predictions. This enables an interpretation of the roles played by the data-driven and model-based elements in output hybrid reservoir computing, resulting in higher explainability of the prediction results. Overall, our findings suggest that the OH approach is the most favorable architecture for hybrid reservoir computing, when taking accuracy, interpretability, robustness to model error, and simplicity into account.
Deep level in the InAs/InAsSb superlattice revealed by forward-bias tunneling
Authors: Rhiger David R.
Published: October 2023

The analysis of forward-bias tunneling data to determine the energy position of a deep level in the gallium-free InAs/InAsSb superlattice is reported. The level is found in p–n junction devices built for mid-wavelength infrared detection. The traps that produce this level can facilitate a trap-assisted tunneling (TAT) current in forward bias that adds to the conventional diffusion dark current. The effect is manifested as a peak in the ideality factor, where the TAT current turns off at a voltage above which the band alignment no longer permits tunneling. We apply the tunneling model of Anderson developed for HgCdTe. Our analysis of data from InAs/InAsSb having a bandgap energy of 220 meV finds the trap energy to be 170 meV above the valence band edge.
Temperature effects of aluminum melt during the infiltration process into porous graphite matrix
Authors: Pan Like , Xia Langyu , Chu Tiangang , Xing Tong , Wei Wenfu
Published: October 2023

Aluminum/graphite composites are receiving much attention due to the unique features and diverse possibilities in different fields. Generally, the aluminum melt into the inner pores of the graphite matrix requires an ambient prompting with high temperature and gas pressure. The infiltration dynamics of aluminum melt, which highly depends on the ambient temperature, would have a significant effect on the final composite’s performance. In this work, we have studied the temperature effect of aluminum melt during the infiltration process into the porous graphite matrix based on numerical simulation and experimental verification. Results show that the moderate temperature increase would effectively promote the infiltration of aluminum melt, achieving a higher filling rate with a shorter filling time. However, the promotion effects of the temperature increase would come to a certain limit due to the opposing effects of capillary porous and residual gas. The detailed influences of the temperature on the infiltration would be presented, and the final composite performance, including mechanical strength and thermal management capability, would be examined and discussed.
Joining mechanism evolution of fusion welded TC4 titanium alloy/304 stainless steel dissimilar joint by GTAW
Authors: Hao Xiaohu , Wei Xinlong , Li Shuhua , Cui Zeqin , Wang Wenxian , Dong Honggang , Li Weiguo
Published: October 2023

Gas tungsten arc welding with a pure Cu filler wire was carried out to join the TC4 titanium alloy and 304 stainless steel. Filling pure Cu filler wire assisted with regulating welding current could effectively restrain the concentrated generation of Ti–Fe brittle intermetallic compounds. Three joining modes exist in the fusion welding titanium alloy and stainless steel. In the partial fusion welding mode, the TiCu phase decreased and the fine granular τ2 phase formed in the Ti/Cu interfacial zone, simultaneously, the molten zone consisted of a Cu solid solution and α-(Fe, Cr) phase formed at the Cu/Fe interface, resulting in mechanical interlocking effect and consequent high tensile strength of 363 MPa. Increasing the welding current would lead to the alloying of Ti xCu y phases, and then enhance the Ti/Cu interface.
Vertical molecular transistors: a new strategy towards practical quantum devices
Authors: Hayakawa Ryoma , Wakayama Yutaka
Published: October 2023

Considerable effort has been dedicated to improving molecular devices since they were initially proposed by Aviram and Ratner in 1974. Organic molecules are small and have discrete molecular orbitals. These features can facilitate fascinating quantum transport phenomena, such as single-carrier tunneling, resonant tunneling, and quantum interference. The effective gate modulation of these quantum transport phenomena holds the promise of realizing a new computing architecture that differs from that of current Si electronics. In this article, we review the recent research progress on molecular transistors, specifically vertical molecular transistors (VMTs). First, we discuss the benefits of VMTs for future molecular-scale transistors compared with the currently dominant lateral molecular transistors. Subsequently, we describe representative examples of VMTs, where single molecules, self-assembled monolayers, and isolated molecules are used as transistor channels. Finally, we present our conclusions and perspectives about the use of VMTs for attractive quantum devices.
PDS-MAR: a fine-grained projection-domain segmentation-based metal artifact reduction method for intraoperative CBCT images with guidewires
Authors: Lyu Tianling , Wu Zhan , Ma Gege , Jiang Chen , Zhong Xinyun , Xi Yan , Chen Yang , Zhu Wentao
Published: October 2023

Objective. Since the invention of modern Computed Tomography (CT) systems, metal artifacts have been a persistent problem. Due to increased scattering, amplified noise, and limited-angle projection data collection, it is more difficult to suppress metal artifacts in cone-beam CT, limiting its use in human- and robot-assisted spine surgeries where metallic guidewires and screws are commonly used. Approach. To solve this problem, we present a fine-grained projection-domain segmentation-based metal artifact reduction (MAR) method termed PDS-MAR, in which metal traces are augmented and segmented in the projection domain before being inpainted using triangular interpolation. In addition, a metal reconstruction phase is proposed to restore metal areas in the image domain. Main results. The proposed method is tested on both digital phantom data and real scanned cone-beam computed tomography (CBCT) data. It achieves much-improved quantitative results in both metal segmentation and artifact reduction in our phantom study. The results on real scanned data also show the superiority of this method. Significance. The concept of projection-domain metal segmentation would advance MAR techniques in CBCT and has the potential to push forward the use of intraoperative CBCT in human-handed and robotic-assisted minimal invasive spine surgeries.
A magnetorheological vibration absorber with bidirectional tunability for pipelines
Authors: Xie Yuanpeng , Fu Jie , Zhu Mi , Qi Song , Tian Ruixue , Yu Miao
Published: October 2023

A magnetorheological elastomer (MRE) is employed as a tunable stiffness element in a dynamic vibration absorber (DVA) due to its remarkable magnetic tunability. However, the natural frequency of the MRE-based DVA can only be tuned towards high frequency under magnetic fields, which fails to solve, or even exacerbates, the low-frequency pipeline vibration. To tackle this issue, an innovative DVA (H-DVA) with bidirectional magnetic tunability is proposed in this paper. The hard magnetic MRE filled by NdFeB particles is selected as the core tunable stiffness element in H-DVA. Besides, the discretization distribution design scheme for the mass oscillators is adopted to improve the flexibility of H-DVA. Then, the magnetic field simulation and resonance frequency shifting test of H-DVA under different magnetic fields are completed to validate the bidirectional magnetic tunability. Lastly, the vibration absorption effect is verified in a self-established experimental pipeline system. The experiment results demonstrate that the resonance frequency of the proposed H-DVA exhibites a maximum frequency shift of approximately −2.7 Hz under reversed magnetic field. Compared to H-DVA working in zero field state, the acceleration magnitude of the pipeline vibration is further reduced by 8.8% when applying −1.5 A to the H-DVA under 55 Hz excitation. Similarly, the acceleration magnitude is further reduced by 22.2% when applying 2 A to the H-DVA under 85 Hz excitation. Thus, these findings confirm that the H-DVA proposed in this paper not only achieves the bidirectional magnetic tunability, but also improves the vibration absorption effect for pipeline vibration.
The discrete canonical commutation relationship
Authors: Martínez-Pérez Armando , Torres-Vega Gabino
Published: October 2023

We use non-standard finite differences to propose a quantum momentum operator to be used when the spectrum of the operator is discrete. The defined discrete operator complies with the discrete versions of the properties that the continuous variable operator has. The discrete derivative is exact for its eigenfunction, that is, exponential functions. We obtain the discrete adjoint of the momentum operator. The canonical commutation relationship between conjugate operators for discrete variables is diagonal along a particular direction.
Phase synchronization under mixed synapse between two heterogeneous functional neurons
Authors: Jiang Lingfeng , Xiong Li , An Xinlei , Zhang Jiangang
Published: October 2023

Nervous system contacts and regulates the various systems and organs of the body by encoding and transmitting information, so it becomes important to explore the synaptic connections between neurons. In this study, two functional neurons are obtained by embedding Josephson junction and memristor in the FHN neuron circuit, and then based on Helmholtz’s theorem their Hamilton energies are calculated and investigated when coupled channel is awakened. There are weak but stable and orderly electromagnetic fields around human tissues and organs due to the transmembrane flow of ions, and their equilibrium state is easily disturbed and destroyed by the external electromagnetic fields, which should be considered when neuron model are investigated. Thus, an induction coil and a charge-controlled memristor (CCM) are used to perceive magnetic and electric fields respectively to couple the two function neurons, then mixed synapse is activated and synaptic plasticity is detect by parameter modulation and energy exchange. It is found that energy is continuously pumped along the coupling channel even if the synaptic connection is increased further, and two different functional neurons can only achieve quasi-phase synchronization or phase lock. However, the coupling strength threshold for achieving quasi-phase synchronization is lowered under hybrid synapses, and the possible mechanism may be that the addition of induction coil and CCM can induce time-varying electric and magnetic fields, which in turn facilitate the energy exchange in the coupled system. This study not only helps us to reveal the synchronization phenomenon of certain neurons observed in experiments, but also to explain the occurrence of pathological synchronization in the nervous system.
Deep learning assisted fractal slotted substrate MIMO antenna with characteristic mode analysis (CMA) for Sub-6 GHz n78 5 G NR applications: design, optimization and experimental validation
Authors: Babu K Vasu , Sudipta Das , Sree Gorre Naga Jyothi , Almawgani Abdulkarem H M , Islam Tanvir , Alhawari Adam R H
Published: October 2023

This article presents the design and optimization of a Deep Learning assisted MIMO antenna for 5 G New Radio (NR) applications in Sub-6 GHz band. The Prototype of the simulated geometry has been practically modelled and experimentally tested to validate the theoretical results. The optimized two-port MIMO antenna of 48 × 24 mm2 size is designed using fractal slotted substrate geometry. The concept of characteristic mode analysis (CMA) method is performed to characterize the performance of the proposed slotted substrate monopole MIMO Antenna. Usually, Optimization techniques based on traditional electromagnetic simulation tools (CST, HFSS, etc) are time-consuming for the design purpose of complex MIMO antenna geometries. The simulation studies using electromagnetic simulation tools are needed to be performed repeatedly to evaluate the optimum geometrical parameters for achieving better acceptable performance. In order to solve this issue, Deep Learning (DL) method-based design optimization approach is considered as an effective technique for determining the optimum physical parameters. In this article, Deep learning method based Dual-Channel type Deep Neural Network (DC-DNN) optimization technique is suggested to estimate the S-parameters. The generated data is fed to DC-DNN acting as a surrogate model to map the input features with the reflection and transmission coefficients, thereby enabling the search for the optimum design parameters to obtain the best performance. The diversity parameters are observed within acceptable limits and the characteristic parameters related to impedance and radiation performance are best suitable for lower sub-6 GHz n78 (3300–3800 MHz) 5 G NR network applications.
Axion helioscopes as solar thermometers
Authors: Hoof Sebastian , Jaeckel Joerg , Thormaehlen Lennert J.
Published: October 2023

Axions, if discovered, could serve as a powerful new messenger for studying astrophysical
objects. In this study we show how the Sun's spatial and spectral “axion image” can be inverted
to infer the radial dependence of solar properties in a model-independent way. In particular, the
future helioscope IAXO may allow us to accurately reconstruct the Sun's temperature profile T(r)
in the region up to about 80% (40%) of the solar radius for an axion-photon coupling
g

aγγ of 6 × 10-11 GeV-1 (10-11 GeV-1). The statistical fluctuations
in the photon data lead to a median precision of better than 10% (16%) in this region, and the
corresponding median accuracy was better than 4% (7%). While our approach can simultaneously
infer the radial profile of the Debye scale κ
s(r), its weaker connection to the
axion production rate leads to median accuracy and precision of worse than 30% and 50%,
respectively. We discuss possible challenges and improvements for realistic setups, as well as
extensions to more general axion models. We also highlight advantages of helioscopes over
neutrino detectors.
Proton capture in compact dark stars and observable implications
Authors: Betancourt Kamenetskaia Boris , Brenner Anja , Ibarra Alejandro , Kouvaris Chris
Published: October 2023

Asymmetric dark matter under certain conditions could form compact star-like objects, which can be searched either through gravitational lensing or by observation of gravitational waves from binaries involving such compact objects. In this paper we analyze possible signatures of such dark stars made of asymmetric dark matter with a portal to the Standard Model. We argue that compact dark stars could capture protons and electrons from the interstellar medium, which then accumulate in the core of the dark star, forming a very hot gas that emits X-rays or γ-rays. For dark matter parameters compatible with current laboratory constraints, compact dark stars could be sufficiently luminous to be detected at the Earth as point sources in the X-ray or γ-ray sky.
Testing needs for the development and qualification of a breeding blanket for DEMO
Authors: Federici Gianfranco
Published: October 2023

The purpose of this paper is to critically review the testing and qualification strategy for the DEMO breeding blanket in Europe, identifying the potential risks and weaknesses and recommending, where necessary, the changes required to strengthen or accelerate the programme. Based on the information presented in this paper, a risk mitigation strategy is required to reduce the technological, licencing, and regulatory risks associated with the performance and reliability of the breeding blanket technologies for DEMO. An attractive mitigation option, which was originally proposed more than 30 years ago but not implemented, is to perform testing and qualification of breeding blanket technologies and design concepts in a dedicated nuclear plasma device that serves as a 14 MeV volumetric neutron source.
A practitioner’s guide to quantum algorithms for optimisation problems
Authors: Symons Benjamin C B , Galvin David , Sahin Emre , Alexandrov Vassil , Mensa Stefano
Published: October 2023

Quantum computing is gaining popularity across a wide range of scientific disciplines due to its potential to solve long-standing computational problems that are considered intractable with classical computers. One promising area where quantum computing has potential is in the speed-up of NP-hard optimisation problems that are common in industrial areas such as logistics and finance. Newcomers to the field of quantum computing who are interested in using this technology to solve optimisation problems do not have an easily accessible source of information on the current capabilities of quantum computers and algorithms. This paper aims to provide a comprehensive overview of the theory of quantum optimisation techniques and their practical application, focusing on their near-term potential for noisy intermediate scale quantum devices. The paper starts by drawing parallels between classical and quantum optimisation problems, highlighting their conceptual similarities and differences. Two main paradigms for quantum hardware are then discussed: analogue and gate-based quantum computers. While analog devices such as quantum annealers are effective for some optimisation problems, they have limitations and cannot be used for universal quantum computation. In contrast, gate-based quantum computers offer the potential for universal quantum computation, but they face challenges with hardware limitations and accurate gate implementation. The paper provides a detailed mathematical discussion with references to key works in the field, as well as a more practical discussion with relevant examples. The most popular techniques for quantum optimisation on gate-based quantum computers, the quantum approximate optimisation algorithm and the quantum alternating operator ansatz framework, are discussed in detail. However, it is still unclear whether these techniques will yield quantum advantage, even with advancements in hardware and noise reduction. The paper concludes with a discussion of the challenges facing quantum optimisation techniques and the need for further research and development to identify new, effective methods for achieving quantum advantage.
Strength Enhancement and Deformability of Confined High-Strength Steel Fiber Concrete After Burning
Authors: Purwanto  , Antonius  , Setiyawan Prabowo , Krisdiyanto Aris
Published: October 2023

This study investigates post-burning steel fibrous concrete that aims to identify the mechanical quantities affecting the behavior of confined steel fibrous concrete after burning. A total of 72 specimens of unconfined concrete and confined concrete were made by reviewing design parameters, namely concrete compressive strength (fc

’), fiber fraction and duration of combustion (1 hour, 2 hours and 3 hours). All specimens were monotonically compressed with a deformation control testing system. The parameters discussed from the experimental results represent the strength of the confined concrete (fccf
’), the peak strain of the confined concrete (εccf
′), and the strain of the confined concrete after the peak stress is exceeded and decreases by 50% (εcc50f
). The experimental results showed that for concrete with higher volume fractions of fiber (0%, 1% and 2%), the relative strength enhancement of confined concrete (K value) indicates an increase in the value of K although it is not significant. On the other hand, in general, the values of εccf′ and εcc50f tend to increase significantly at post peak response, if the confined steel fiber concrete specimen is burned for a longer time and volume fraction of fiber were higher. The increase in the strain of confined concrete is one indication that the specimen is more ductile with increasing burning time.
Numerical Study on Slender Circular Reinforced Concrete Column Clamped with Steel Sheet
Authors: Yansiku Sandy I. , Piscesa Bambang , Suprobo Priyo
Published: October 2023

Various methods to enhance the performance of circular reinforced concrete column have been widely investigated. However, most researches used internal strengthening method such as intensifying steel reinforcement. Others utilized carbon fiber reinforced polymer (CFRP), glass fiber and aramid to retrofit either reinforcement or concrete surface. Few studies incorporated steel to cover concrete surface but neglecting clamp pressure between steel and concrete surface. This study proposes a steel sheet strap strengthening method by initial clamping stress on steel sheets as an external confining technique through experimental works and in-depth numerical analysis. The experimental investigation includes nine steel sheet strengthened reinforced concrete specimens of 20 MPa subjected to axial concentric and axial eccentric. Retrofitting devices will be fabricated from BJ37 steel. Steel sheet straps in each specimen will be subjected to varying initial clamp pressure by fastening bolts. Applied load, lateral displacement and vertical and horizontal deformation will be measured by the instrumentation. Experimental works will observe failure mode, force displacement, stress and ductility. Section analysis based on experimental results will define compatibility equations for numerical stage. Strengthening model from experimental stage will also be analyzed in numerical study with inhouse software 3DNLFEA. F-D curve and moment-curvature loading behavior and ductility will be obtained from numerical analysis. It is believed that the proposed strengthening mechanism with its geometrical and stress variations could enhance the section, member and structural ductility of circular reinforced column against vertical and lateral load. Furthermore, the developed analytical model could well predict the behavior of the proposed clamp mechanism for practical applications.
Experimental study on replaceable shear link on reinforced concrete shear wall
Authors: Moestopo M , Kusumastuti D , Kurniawan
Published: October 2023

Experimental study has been conducted on specimens of a half-scale coupled reinforced concrete shear wall with steel coupling beam and an inserted shear link, to investigate the seismic performance of the core-wall and the replaceability of the shear link as a mechanical damper to dissipate the seismic energy. The link was designed following requirements for typical shear link, while the coupling beams as well as the shear wall were designed based on the link capacity. The result showed that under the prescribed cyclic loading (AISC 341-2016), the sub-assembly performed as expected, as shown by a good hysteretic curve with the plastic strain of shear link exceeded 0.08 radian. The damage was limited on the shear link, while the steel coupling beam and steel bar in the reinforced concrete wall remained elastic. Moreover, the experimental study showed no permanent distortion on the steel coupling beam after series of shear-link replacement. This confirmed the replaceability of the shear links as an excellent seismic device in the core-wall system.
Hybrid viscoelastic damper using natural rubber compound, waste of rubber tire crumb with various compacted sands (iron sand, natural sand, and silica sand) to increase damping property for non-engineered buildings
Authors: Edwin  , Priyosulistyo Henricus
Published: October 2023

To reduce lateral deformation due to earthquake shake has been carried out by strengthening techniques. Such techniques require additional structural elements such as bracing or shear wall, if not applying additional new materials on beams or columns such as CFRP. This study focuses on the formation of the hybrid rubber dampers from materials such as natural rubber compound (NRC), waste of rubber tire crumb (WRTC), compacted natural sand, iron sand, and silica sand. The main goal of this research is to investigate the dynamic properties of hybrid materials of compacted various sands encapsuled with the NRC and WRTC compound. Nonetheless, the mechanical properties of rubber, such as tensile strength and modulus of elasticity, were also tested. In this research, the specimens were in the form of a square block of 100 x 100 mm2 base and 25 mm thickness and consisted of two types of specimens for reference i.e., fully natural rubber compound (NRC) and blended NRC with 25% by volume of the WRTC, namely MRTC. Furthermore, other three types of hybrid viscoelastic dampers (HVD) were also provided i.e., 1) compacted natural sand, 2) compacted iron sand, and 3) compacted silica sand, which were all wrapped with WRTC in a proportion of 3:4 by volume. The results show that the addition of the MRTC reduces the tensile strength and elastic modulus in comparison to the NRC but increases the damping properties. Moreover, the elaboration of compacted natural sand, iron sand, and silica sand in the HVD also shows an increase in the damping properties up to 200%.
Shear Capacity of Hollow Reinforced Concrete Members without Stirrups
Authors: Thamrin R , Dewi SH , Asrianur A , Yastari FP , Zaidir Z , Haris S
Published: October 2023

This paper presents experimental results on the shear capacity of hollow reinforced concrete members without stirrups. The area of the hollow was 2.32% of the concrete cross-sectional area. The hollow size used in this study is smaller than the maximum percentage required in the code, where the maximum hollow area was 4% of the total cross-sectional area. The longitudinal reinforcement used in the specimen varies with the three types of reinforcement ratios. The test was carried out using the four-point shear test to achieve the expected shear failure mode. The loading was given monotonically until the specimen failed. Analytical flexural capacity was also calculated using the fiber element method. The specimens failed in shear failure mode, indicated by large diagonal cracks in the observed shear span. The influence of the hollow on the shear strength was also compared with the theoretical shear capacity proposed by the code. This comparison shows that the calculated theoretical shear capacity is conservative for hollow reinforced concrete structural elements with a hollow area smaller than 4%. The results of the flexural analysis show that all the specimens did not reach the flexural capacity due to premature shear failure.
The Effect of Adding Gypsum and Lime on Lightweight Interlock Bricks with Merapi Sand as Fine Agregat
Authors: Rakhmawati A , Murtopo A , Sanviani A , Yuwana D S A , Amin M , Arnandha Y
Published: October 2023

Lightweight materials will reduce the earthquake forces received by the structure. Interlock lightweight brick is a new innovation in the building industry that functions as wall material. Utilization of local materials in Central Java-Yogyakarta, namely Merapi sand, needs to be developed to maximize its potential utilization as an aggregate of lightweight interlock brick. In many research, lime and gypsum as additives have been shown to improve the quality of concrete. This study aims to determine the characteristics of the addition of gypsum and lime as an added material for lightweight interlock bricks with fine aggregate of Merapi sand. The standard of test object and the test refers to SNI 8640-2018. The results showed that in dry weight all the mixed variations were categorized in the 900 kg/m3 and 1100 kg/m3 classes. All variations also complied with water absorption requirements in SNI 8640-2018, but only variations of 2.5% gypsum addition and 5% lime addition meet the compressive strength requirements. This mixture has the highest average of compressive strength value compared to other mixtures. Based on SNI 8640-2018 lightweight interlock bricks with the addition of 2.5% gypsum and 5% lime can be used as wall bricks.
Performance Evaluation of Structures with Buckling Restrained Braced Frame Under Earthquake Load
Authors: Sari D Y , Lim E
Published: October 2023

Structures with buckling-restrained braced frames (BRBF) resist lateral load, i.e., earthquake, using special bracings that yield under axial tension and compression loads. Following the applicable building code SNI 1726-2019, the design for the BRBF structure has a limitation on the structure height for seismic design category D, which is 48 meters. Three structures are modelled: a 5-story building, a 10-story building, and a 20-story building, to evaluate the height limitation on the code. The initial design of the structures used modal response spectrum analysis (MRSA), then the structures were checked using linear response history analysis (LRHA). Finally, a pushover analysis was conducted to obtain the structural performance level. The study revealed that the structural design for BRBF with MRSA satisfies all requirements of SNI 1726-2019. However, the results of the evaluation of BRBF with LRHA show a structure exceeding the height limit does not meet the requirement for inter-story drift. The pushover analysis showed that the structure’s performance reached the Immediate Occupancy (IO) level. Thus, all structures with BRBF in this study that were designed using MRSA have satisfactory performance under the seismic design load, even though the height limit has been exceeded.
Analysis Of RC Precast Modular Building with Frame Element Approach
Authors: Johan C , Satyarno I , Awaludin A , Fikri R , Setiawan A F
Published: October 2023

Concrete buildings with modular systems are still not widely used for high-rise buildings. One of the main reasons is the lack of knowledge regarding the structural design of concrete modular buildings. In Indonesia itself, there are not even many concrete modular buildings because the majority of the area is surrounded by earthquake zones. This study aims to develop a frame analysis method using a section designer for structural analysis of concrete modular buildings. The function of using frame elements is to simplify the calculations that should be modelled with shell elements in order to ensure that the connection between segments occurred only vertically. The analysis was carried out for an 8-storey apartment modular building composed of 4 module segments (M-24A, M-24B, M-36A and M-36B). Seismic analysis was carried out using the parameters of the city of Kutai with Sds
= 0.27 and Sd1
= 0.3. All module segments are capable of enduring the maximum moment caused by seismic loading. The M-36B segment has a maximum moment capacity of 62,318.73 kNm and can withstand an ultimate moment of 2,227.55 kNm. The combined effect of the earthquake due to the response spectrum created maximum building story drift of 0.11% does not exceed the required limit of 2%.
The effect of floor slabs in a structure with frame shear walls modeling in pushover analysis
Authors: Sweiga A G Y , Satyarno I , Supriyadi B
Published: October 2023

Pushover is a nonlinear static analysis method that provides information on nonlinear structures’ behavior due to earthquakes. Subsequently, it has been recommended as a reliable tool to help know the capacity of structures. Another consideration is its easiness of interpretation than the nonlinear dynamic analysis. Numerical modeling of the structure plays an important role in this analysis since every detail of modeling could give different results. The objective of this study is to analyze the effect of the existence of floor slabs in a structure with frame shear walls modeling, which considers the frequent attempt to simplify structural modeling. The effect of the position of components assignation is going to be analyzed too, especially floor slabs and beams, whether it was assigned with centroid or top center insertion point in pushover analysis. In this study, an existing hospital building with vertical irregularity has been modeled into four various models using SAP2000. As the result of pushover analysis, every model gives its pushover curves which reflect its behavior. Those results show that the models with floor slabs have higher capacities. In addition, the combination of the assignation of floor slabs and the top center insertion point gives the highest capacity compared to the other models.
Dynamic field load testing of a horizontally curved longspan LRT Kuningan bridge using eccentric mass vibrator and experimental modal analysis
Authors: Santoso B , Pramudito A , Zamad M K
Published: October 2023

Light Rail Transit (LRT) infrastructure in Indonesia is developing at a rapid pace. The LRT challenging construction is the Kuningan-Longspan Curved bridge with a span of 148 meters and the radius of curvature R = 115 meter. Therefore, Kuningan LRT Bridge is considered as one of the longest concretes curved balanced cantilever LRT Bridge in the world. The implementation of bridge regulations in Indonesia requires a functional feasibility test before the bridge is operational. In the case of the Kuningan LRT bridge, functional feasibility tests were carried out in the form of static and the dynamic tests. The dynamic load test aim is finding the structure natural frequency in the vertical, Longitudinal and Transverse direction. There are 3 methods that being used to measure the dynamic parameters of the train bridge structure in Indonesia. The first method is the Impulsive method using the moving train with the speed of 25 Km/hour as a load. The second method is the usage of The Experimental Modal Analysis and the third method is the combination method of Experimental Modal Analysis with a vibrating instrument in the form of an Eccentric Mass Vibrator (Exciter). The experiment results and the modal fem from the designer is compared and presented in this paper.
Performance-based Analysis of Building Structures in Various Earthquake Zones
Authors: Nurjannah S A , Rosidawani  , Saloma  , Hanafiah  , Rafly M
Published: October 2023

The structural design of an eight-story building was examined to determine its performance in resisting ultimate loads. This was necessary for applying the building design in Indonesian regions with low to high seismic hazard levels. Studies have indicated that pushover analysis is suitable to assess the capacity of building structures against earthquake loads. However, as the structural design of each building produces its nominal strength, performance analysis must always be conducted. This study aimed at comparing the structural performance of buildings in regions with low, medium, and high seismic hazards, represented by the cities of Palembang, Jakarta, and Palu, respectively. A performance-based analysis was conducted using the pushover method to obtain the performance points. The responses of the building structures were the base shears, floor drifts, and inter-story drifts. The structural performance levels in the three regions were between immediate occupancy and life safety or were categorized as damage control, indicating minor damage. Because the structures exhibited high stiffness and ductility, they resisted the ultimate forces up to the damage control performance level in all regions. The greatest lateral drifts of 79.744 mm and 51.656 mm in the X- and Y-axis directions, respectively, occurred in Palu’s high seismic hazard region. The lowest lateral drift occurred in Palembang’s low seismic hazard region, in the X- and Y-axis directions of 59.401 mm and 38.378 mm, respectively.
Non-engineering house damage after the February 25th, 2022 West Pasaman Earthquake
Authors: Fauzan  , Istijono B , Ismail F A , Narny Y , Putra Y S
Published: October 2023

The earthquake that occurred on February 25, 2022 with a magnitude of M6.2 in West Pasaman Regency, West Sumatera has resulted in many losses such as casualties and damages to infrastructure, especially residential buildings. To determine the level of damage to community houses due to the earthquake, a rapid visual assessment survey was conducted with the National Agency for Disaster Countermeasure (BNPB) and 100 Civil Engineering students. The Method used in this survey is based on the Public Work Minister Regulation, which categorizes the damaged houses into 3 categories, namely light, moderate and heavy damage. Based on the results of the assessment, the damage generally occurred on the walls and structural elements of the houses. The damages is caused by human error factors such as lack of planning, poor construction implementation, site selection and selection of quality building materials that were not in accordance with earthquake safe house building standards. One of the efforts to overcome the problem of the damage is to strengthen the house using a ferrocement layer. The level of buildings damage based on the distance from the earthquake center and the implementation of retrofitting on the damaged houses are also discussed in this paper.
Tunnel Stability Analysis Under Seismic Load Using Finite Element Method: A Case Study of Spillway Tunnel, Sidan Dam, Bali, Indonesia
Authors: Arianto Benny , Gde Budi Indrawan I , Wayan Warmada I
Published: October 2023

The location of the Sidan Spillway Tunnel, as shown on the Earthquake Hazard Zone Map of Bali Island, is in a moderate hazard zone. The support system of the spillway tunnel of the Sidan Dam, Indonesia, was empirically designed based on rock mass classification systems. The objective of this research was to verify the performance of the proposed support system by a numerical method considering the uncertainty in using rock mass classification systems for designing a tunnel support system. In addition, being located in an active seismic region, the seismic load was not considered in the empirical tunnel support design. The proposed tunnel support design was numerically modeled in two dimensions using a finite element method and subjected to a seismic load obtained from probabilistic seismic hazard analysis. A numerical analysis without seismic load was also conducted for comparison. Phase2 software was used for the tunnel stability analysis. The input parameters in the numerical analysis were derived from field investigations (surface engineering geological mapping and evaluation of drilling cores) and laboratory tests. The spillway tunnel area consists of pyroclastic rocks, and the Generalized Hoek-Brown Failure Criterion was selected for the strength parameter of rocks. The suggested support designs are systematic rock bolts (20 mm diameter fully grouted), wired mesh, shotcrete, and steel ribs at specific locations. The numerical models determined that applying the proposed tunnel support system recommended based on the empirical method resulted in a roof strength factor of more than 1.5 under static load & 1.1 under seismic load and roof displacements lower than a 10 cm maximum displacement at every stage of construction. The results verify that the tunnel construction will be stable and fulfill the required safety standard, both under and without seismic loads.
Identifying the potential development of HAZUS model as an earthquake disaster loss model for school buildings in Indonesia
Authors: Milyardi R , Pribadi K S , Meilano I , Lim E
Published: October 2023

Located in a complex tectonic zone, Indonesia is prone to earthquakes, which cause considerable damages to houses and buildings and lead to significant economic losses. One of the most significant damages to public facilities is the destruction of school buildings. In addition to hazard factor, poor building structure in most of Indonesia’s school buildings have contributed to increased earthquake disaster losses as a vulnerability component. To reduce disaster losses, quantifying earthquake disaster losses was conducted as an initial process. In practice, Indonesian government and Indonesia’s National Disaster Management Agency (BNPB) calculate disaster losses at the time of post-disaster using various methods. Such calculation method is generally time-consuming, which may impeded the disaster response process. Thus, pre-disaster disaster losses quantification method could be a solution to this problem, which have not been developed and widely applied in Indonesia. HAZUS model is used for estimating earthquake disaster losses in the pre-disaster phase and has been widely used based on the building performance developed by FEMA, USA. This study aims to identify the potential for developing the HAZUS model as a tool for estimating disaster losses in school buildings in Indonesia. The identification was conducted in four stages. The analysis of HAZUS models consisted of hazard analysis, capacity analysis, damage analysis, and losses analysis. A case study was conducted on disaster losses potential mapping in Cicendo District, Bandung City, Indonesia. On the hazard analysis, hazard data were applied on the basis of the Indonesian earthquake hazard and 2017 source map and building code of SNI 1726:2019 as response spectrum procedure. In the analysis of the building capacity, potential development was identified based on capacity building parameters (Ay, Dy, Au, Du) specific to the typical school building in Indonesia with a survey approach and analysis of existing buildings. Concrete Frame with infill masonry shear walls (C3) and Reinforced Masonry Wall with flexible diaphragms (RM1) were identified as the types of structures, which were close to the typical school buildings in Indonesia. The difference of local structure characteristics was identified as the potential to develop fragility curves of local structure on the damage analysis. In the losses analysis, four components of economic loss were applied, consisting of building replacement and repairment of losses, income losses, and building relocation losses. The potential and challenges lie in the use of limited taxonomic data on buildings and school administration data, as well as in the historical data approach to the costs and duration of school building repairs.
Liquefaction Potential Analysis and Soil Improvement Method for Yogyakarta-Bawen Toll Road in Sleman, Yogyakarta
Authors: Kevin P , Wardani S P R , Muhrozi  , Atmanto I D
Published: October 2023

Based on soil investigation using SPT in the planned Yogyakarta-Bawen Toll Road in Sayengan District, Sleman Regency, the soil layers consist of sandy silt, fine-coarse sand, and gravel. Several studies that used the Idriss & Boulanger method showed the liquefaction potential in all observed locations is between high and very high. Therefore, the proposed soil improvement methods are stone columns and jet grouting. Further analysis is conducted to define the effective diameter of the column based on the excess pore pressure ratio (Ru) in both alternatives using the finite difference method (FDM). The result of Ru and CSR analysis in BH 78 showed that by using a 1.2 m diameter stone column in the triangular grid with 2.2 m spacing, Ru max is reduced by 54.75%, and SF liquefaction is improved to 1.202. Alternatively, soil improvement by using a 1.0 m diameter jet grouting in the rectangular grid with 3.0 m spacing showed Ru max is reduced by 11.41% and SF liquefaction is improved to 2.373. Therefore, improvement with the stone column simultaneously reduces Ru max and cyclic stress ratio (CSR), on the other hand, the jet grouting only reduces the cyclic stress ratio.
Analysis of Liquefaction Potential in Solo-Yogyakarta-NYIA Kulon Progo Sta. 16+700 – 22+500
Authors: Yulianisa  , Hardiyatmo HC , Faris F
Published: October 2023

The Solo-Yogyakarta-NYIA Kulon Progo is a National Strategic Project to accelerate the accessibility to New Yogyakarta International Airport (NYIA). This toll road will pass through Central Java Province and the Special Region of Yogyakarta Province. Previous studies have investigated that during the 2006 Yogyakarta Earthquake with a moment magnitude, Mwof 6.3, liquefaction was found in some areas in Klaten Regency of Central Java Province. This study aims to determine liquefaction potential in the Solo-Yogyakarta-NYIA Kulon Progo Toll Road Section 1, focusing on stations 16+700 to 22+500, which were located in Klaten Regency. This study first analyzes soil conditions and groundwater depth based on soil investigation data. Analysis of liquefaction potential was found out using Idriss-Boulanger based on Standard Penetration. Parameter of peak ground acceleration using two approaches; probabilistic and deterministic. For probabilistic, the peak ground acceleration using probability of 7% in 75 years and 2% in 50 years. For deterministic using the attenuation function of Campbell and Bozorgnia (2014). Then, the Liquefaction Potential Index was also used to determine the level of liquefaction vulnerability in the study area. The results of liquefaction potential analysis using each approach of peak ground acceleration show the differences in safety factor of liquefaction values. It can be concluded that several sites along the study area have the potential to liquefy at a very low to a very high level, with PGA value at least 0,43 for probability of 2% in 50 years, 0,32 for probability of 7% in 75 years, and 0,36 for deterministic approaches sourced by Opak Fault. Then, the location with the highest liquefaction potential is at stationing 20+550, with LPI values of each approach of 42.91, 33.36, and 34.70.
Study of soil liquefaction potential at Anutapura General Hospital, Palu City, Central Sulawesi Province
Authors: Septiadi D R , Hardiyatmo H C , Faris F
Published: October 2023

On September 28, 2018, at 18:02 local time, a strong tectonic earthquake with a moment magnitude of 7.5 struck Central Sulawesi Province, Indonesia, triggering liquefaction disasters in Palu city and Sigi district. The project of the Anutapura Medical Centre (AMC) building at the Anutapura General Hospital in Palu city is one of the Indonesian government programs to support the rehabilitation and reconstruction of infrastructure after the earthquake. This hospital is located close to the liquefaction-affected area in Balaroa. Geologically, the hospital area is also located in the formation of Holocene deposits that have not been fully lithified. This study aims to analyze the liquefaction potential, which focuses on the construction area of the AMC building. The soil grain size distribution was used for the preliminary analysis of potentially liquified soils. The SPT-based liquefaction triggering procedure was used to calculate the safety factor (SF) against liquefaction. Subsequently, the SF value was further analyzed using the liquefaction severity index (LSI) to determine the severity level. The results show that soils in the study area have the potential to liquefy with a low to moderate severity level. The results are expected to be used as consideration to mitigate the possible liquefaction.