bluuebunny/crossref_metadata_2025 huggingface dataset:
Co-management for sustainable development and conservation in Sanjiangyuan National Park and the surrounding Tibetan nomadic pastoralist areas
Authors: Ma Ting , Swallow Brent , Foggin J. Marc , Zhong Linsheng , Sang Weiguo
Published: June 2023

The Qinghai-Tibet Plateau plays an essential role in national to regional ecological security, biodiversity conservation, and sustaining livelihood. An array of natural resource management, environmental conservation, and ecological restoration projects have been trialed and implemented in recent years in the vast Sanjiangyuan region of the central Qinghai-Tibet Plateau, aiming especially to ensure socio-ecologically appropriate and sustainable development of animal husbandry in the alpine grasslands. Novel approaches in China have included the introduction of more collaborative approaches in protected area management and the development and formal establishment of a new multi-purpose national park system. Many milestones have been achieved. However, such developments are driven largely by national and global goals and very little has been heard to date directly from the people most affected: those residing within the protected landscapes, i.e. the community stakeholders themselves. This empirical, perceptions-based study aims to partially fill this gap, drawing on the results of focus group discussions with community representatives supplemented by key informant interviews and a targeted review of the literature, to provide synthesized feedback and priority recommendations for improving “community co-management” collaborations for the joint benefit of Tibetan herders and protected areas. The mixed-method approach employed in this study was based on a conceptual model derived from Elinor Ostrom’s social–ecological systems framework, calibrated to local residents’ self-assessments of their household well-being. Results highlight how the most recent configuration of China’s national park model (i.e., its form and the approaches it utilizes) is generally deemed successful by community stakeholders, albeit with some notable perceived limitations mainly relating to a sense of lack of fairness and inclusiveness in the “one household, one post” co-management mechanism. The paper closes with discussion and recommendations around fundamental issues of equity, empowerment, and gender, finally pointing to the significance and, ultimately, the need to move even beyond co-management per se and to adopt a model of inclusive governance for conservation wherein joint deliberations and decision-making amongst diverse stakeholders are prioritized over the simple implementation of externally developed programs and management plans.
60 Gbps real-time wireless communications at 300 GHz carrier using a Kerr microcomb-based source
Authors: Heffernan Brendan M. , Kawamoto Yuma , Maekawa Keisuke , Greenberg James , Amin Rubab , Hori Takashi , Tanigawa Tatsuya , Nagatsuma Tadao , Rolland Antoine
Published: June 2023

Future wireless communication infrastructure will rely on terahertz systems that can support an increasing demand for large-bandwidth, ultra-fast wireless data transfer. In order to satisfy this demand, compact, low-power, and low noise sources of terahertz radiation are being developed. A promising route to achieving this goal is combining photonic-integrated optical frequency combs with fast photodiodes for difference frequency generation in the THz. Here, we demonstrate wireless communications using a 300 GHz carrier wave generated via photomixing of two optical tones originating from diode lasers that are injection locked to a dissipative Kerr soliton frequency microcomb. We achieve transfer rates of 80 Gbps using homodyne detection and 60 Gbps transmitting simultaneously both data and clock signals in a dual-path wireless link. This experimental demonstration paves a path toward low-noise and integrated photonic millimeter-wave transceivers for future wireless communication systems.
Simple experimental realization of optical Hilbert Hotel using scalar and vector fractional vortex beams
Authors: Kumar Subith , Ghosh Anirban , Kaushik Chahat , Shiri Arash , Gbur Greg , Sharma Sudhir , Samanta G. K.
Published: June 2023

Historically, infinity was long considered a vague concept—boundless, endless, larger than the largest—without any quantifiable mathematical foundation. This view changed in the 1800s through the pioneering work of Georg Cantor, who showed that infinite sets follow their own seemingly paradoxical mathematical rules. In 1924, David Hilbert highlighted the strangeness of infinity through a thought experiment now referred to as the Hilbert Hotel paradox, or simply Hilbert’s Hotel. The paradox describes a “fully” occupied imaginary hotel having an infinite number of single-occupancy rooms. The manager can always find a room for new guests by simply shifting current guests to the next highest room, leaving the first room vacant. The investigation of wavefield singularities has uncovered the existence of a direct optical analogy to Hilbert’s thought experiment. Since then, efforts have been made to investigate the properties of Hilbert’s Hotel by controlling the dynamics of phase singularities in “fractional” order optical vortex beams. Here, we have taken such proposals to the next level and experimentally demonstrated Hilbert’s Hotel using both phase and polarization singularities of optical fields. Using a multi-ramped spiral-phase-plate and a supercontinuum source, we generated and controlled fractional order vortex beams for the practical implementation of Hilbert’s Hotel in scalar and vector vortex beams. Using a multi-ramped spiral-phase-plate, we show the possibility for complicated transitions of the generalized Hilbert’s Hotel. The generic experimental scheme illustrates the usefulness of structured beams in visualizing unusual mathematical concepts and also for fractional vector beams driven by fundamental and applied research.
Vibrational strong coupling in liquid water from cavity molecular dynamics
Authors: Lieberherr Annina Z. , Furniss Seth T. E. , Lawrence Joseph E. , Manolopoulos David E.
Published: June 2023

We assess the cavity molecular dynamics method for the calculation of vibrational polariton spectra using liquid water as a specific example. We begin by disputing a recent suggestion that nuclear quantum effects may lead to a broadening of polariton bands, finding instead that they merely result in anharmonic red shifts in the polariton frequencies. We go on to show that our simulated cavity spectra can be reproduced to graphical accuracy with a harmonic model that uses just the cavity-free spectrum and the geometry of the cavity as input. We end by showing that this harmonic model can be combined with the experimental cavity-free spectrum to give results in good agreement with optical cavity measurements. Since the input to our harmonic model is equivalent to the input to the transfer matrix method of applied optics, we conclude that cavity molecular dynamics cannot provide any more insight into the effect of vibrational strong coupling on the absorption spectrum than this transfer matrix method, which is already widely used by experimentalists to corroborate their cavity results.
Influence of external environment parameters on friction coefficient between hoisting-rope and its pads
Authors: Kou Baofu , Li Zhenshun , Li Ruiqing , Wang Zhaohua , Zhao Xinlin
Published: June 2023

The friction coefficients between the hoisting-rope and friction pads made of different materials under different environmental conditions, load sizes, and load frequencies were investigated by using a friction and wear tester. The variation law of the friction coefficient with the change in the working condition parameters was explored through orthogonal test analysis; it is found that dry friction, a load of 100 N, and a frequency of 1 Hz are the optimal working conditions to achieve an optimal friction coefficient of the matching pair of the hoisting-rope and friction pads. Among them, the friction coefficient of the K25 pad is greatly affected by the environment, while the friction coefficient of the G30 pad is greatly affected by load. The results under all working conditions show that the friction coefficient of the K25 pad is greater than that of the G30 pad but the wear resistance of the G30 pad is better than that of the K25 pad. In terms of wear resistance, the K25 pad performs better under dry friction conditions than under other environmental conditions, while the G30 pad performs better under rain conditions. The conclusion can provide theoretical guidance for the reasonable matching between the hoisting-rope and its pads under different environmental conditions.
Novel and emerging seed science research from early to middle career researchers at the Australasian Seed Science Conference, 2021
Authors: Everingham Susan E. , Chen Si-Chong , Lewandrowski Wolfgang , Plumanns-Pouton Ella
Published: June 2023

Seed science is a vital field of research that contributes to many areas of knowledge in fundamental ecology and evolution, as well as in applied areas of food production, and the conservation and restoration of native plants. A large amount of novel information, technologies and processes in seed science research are being produced and developed by early to middle career researchers (EMCRs) in academic, government and private science sectors. This breadth and novelty of research by EMCRs was evident at the second Australasian Seed Science Conference held online in September 2021. EMCRs represented almost one-third of the presenting delegates at the conference and covered research in areas including functional seed trait relationships, responses of seed traits and germination to environmental change, managing seeds in ex-situ seed and germplasm collections and using seeds as food sources. As future environmental, social and economic challenges arise, EMCR seed scientists will be at the forefront of emerging fundamental ecological and evolutionary seed science knowledge, as well as the development of technologies and processes for the conservation of native species, the utilisation of seeds in agriculture and food production, and many new ideas yet to be discovered.
Highly Tunable Perpendicular Magnetic Anisotropy and Anisotropic Magnetoresistance in Ru-Doped La0.67Sr0.33MnO3 Epitaxial Films
Authors: Hua Enda , Dai Kunjie , Wang Qing , Ye Huan , Liu Kuan , Zhang Jinfeng , Lu Jingdi , Liu Kai , Jin Feng , Wang Lingfei , Wu Wenbin
Published: June 2023

As a prototypical half-metallic ferromagnet, La0.67Sr0.33MnO3 (LSMO) has been extensively studied due to its versatile physical properties and great potential in spintronic applications. However, the weak perpendicular magnetic anisotropy (PMA) limits the controllability and detection of magnetism in LSMO, thus hindering the realization of oxide-based spintronic devices with low energy consumption and high integration level. Motivated by this challenge, we develop an experimental approach to enhance the PMA of LSMO epitaxial films. By cooperatively introducing 4d Ru doping and a moderate compressive strain, the maximum uniaxial magnetic anisotropy in Ru-doped LSMO can reach 3.0 × 105 J/m3 at 10 K. Furthermore, we find a significant anisotropic magnetoresistance effect in these Ru-doped LSMO films, which is dominated by the strong PMA. Our findings offer an effective pathway to harness and detect the orientations of magnetic moments in LSMO films, thus promoting the feasibility of oxide-based spintronic devices, such as spin valves and magnetic tunnel junctions.
Historic and physical wandering domains for wild blender-horseshoes
Authors: Kiriki Shin , Nakano Yushi , Soma Teruhiko
Published: June 2023

We present diffeomorphisms of wild blender-horseshoes which belong to

C
r

 
(
1
⩽
r
<
∞
)

closures of two types of diffeomorphisms, one of which has a historic contracting wandering domain, and the other has a non-trivial Dirac physical measure supported by saddle periodic orbit. It is a non-trivial extension of Colli–Vargas’ model (Colli and Vargas 2001 Ergod. Theory Dyn. Syst.
21 1657–81) to the higher dimensional dynamics with the use of wild blender-horseshoes.
Transport properties of
Fe60Al40
during the
B2
to
A2
structural phase transition
Authors: Sorokin Serhii , Anwar Md Shadab , Hlawacek Gregor , Boucher Richard , Salgado-Cabaco João , Potzger Kay , Lindner Jürgen , Faßbender Jürgen , Bali Rantej
Published: June 2023

The variation of transport behavior in a mesoscopic

F
e

60

A
l

40

wire, initially possessing the ordered

B
2

-phase structure, has been observed while inducing a phase transition to the disordered

A
2

phase. Gradual disordering was achieved using a highly focused beam of

N
e

+

-ions. Both electrical resistance and anomalous Hall effect were measured simultaneously and in situ during the local ion irradiation. The normal as well as the Hall resistivity show a peak as a function of disorder. The relationship between Hall resistivity and normal resistivity shows the presence of two distinct transport regimes during the phase transition. Ex situ field- and temperature-dependence measurements show that it is necessary to consider the effect of scattering from magnetic clusters to understand these different regimes in transport properties.
Evolution of bulk magnetic structure in MnSi thin film: a soft x-ray magnetic circular dichroism study
Authors: Jena S , Choi W-Y , Gardner J , Jung M H , Srivastava S K , Verma V K , Amemiya K , Singh V R
Published: June 2023

Skyrmionic materials have exceptionally stable topologically protected chiral structures, the B20 helimagnetic MnSi is regarded as the best contender in this category. A non-centrosymmetric polycrystalline, MnSi thin films were fabricated on a c-sapphire substrate using a radio-frequency magnetron sputtering method. The structural and optical characteristics of the topological MnSi were examined using x-ray diffraction, Ultraviolet-visible spectroscopy, and Fourier-transform infrared spectroscopy technique. The most sophisticated tools like Vibrating sample magnetometer, element-specific soft x-ray absorption spectroscopy and soft-x-ray magnetic circular dichroism (XMCD) were used to probe its electronic and magnetization behaviour. The material exhibits a higher degree of magnetization signifying ferromagnetism in the bulk region as observed at ∼ 300 K and ∼ 670 K. The measured XMCD intensity at 300 K in the bulk-sensitive total-fluorescence-yield mode increased from 0 T to 2 T, which also raises the possibility of long-range ferromagnetic ordering in it. In this perspective of research, MnSi is recognised as a developing material for spintronic-based devices.
A single long NiTi tube compressive elastocaloric regenerator: experimental results
Authors: Cheng Siyuan
Published: June 2023

Elastocaloric cooling is an environmentally friendly alternative to the current vapor-compression refrigeration technology, and the development of an efficient operation strategy is significant for its commercialization. In this article, the cooling performance including the temperature span, specific cooling power, and coefficient of performance for a novel single long NiTi tube compressive elastocaloric regenerator (tube outer diameter 5 mm, wall thickness 1 mm, and initial length 305 mm) was comprehensively characterized under different operation parameters (operation cycle time, loading/unloading time, heat transfer fluid timing, flow time, and utilization). The single long NiTi tube compressive elastocaloric regenerator achieved maximum temperature span, specific cooling power, and coefficient of performance of 5.7 K, 135 W·kg−1, and 4.7, respectively under an applied strain of 2.5%. It was found that the most important factors for obtaining a good cooling performance of the single long NiTi tube compressive elastocaloric regenerator were a short operation cycle time, a proper heat transfer fluid timing, and a proper heat transfer fluid utilization. The dependences of the temperature span on the cycle time and heat transfer fluid utilization factor were in agreement with the existing experimental data for a parallel plate tensile elastocaloric regenerator. A thinner tube wall thickness and advanced cross-section geometry for the regenerator may further improve the cooling performance of the compressive elastocaloric regenerator.
Study on magnetic and thermodynamic characteristics of graphyne-like sandwich structure
Authors: Shi Kai-Le , Wang Chao-Fan , Jiang Wei
Published: June 2023

By employing effective-field theory with correlations, the effects of exchange couplings and anisotropies on the physical properties of graphyne-like sandwich structure with a mixed-spin (5/2, 2) were analyzed. The various characteristic curves of the hysteresis loops, magnetization, susceptibility, internal energy, specific heat, as well as phase diagram was obtained. We found the multiple-loop hysteresis behaviors and reentrant phenomenon under certain conditions. Moreover, we also depicted the variation curves of dynamic magnetization under the impact of a periodically oscillating magnetic field. It is shown that a time-dependent and independent magnetic field can control and induce the disorder and order of the system.
Transitioning from a bounce to R
2 inflation
Authors: Daniel Richard , Campbell Mariam , van de Bruck Carsten , Dunsby Peter
Published: June 2023

Non-singular bouncing cosmologies are well-motivated models for the early universe. Recent observational data are consistent with positive spatial curvature and allow for a natural collapsing and bouncing phase in the very early universe. Additionally, bouncing cosmologies have the potential to rectify conceptual shortcomings identified in the theory of inflation, such as the singularity problem. In this paper we present a classical bouncing model in the context of modified gravity, including an R
2-term in the action. We show that after the bounce, the universe enters naturally a period of inflation, driven by the R
2-term. We analyse the stability of the model and find that the scalaron assists the stability of the model.
Dark energy on astrophysical scales and its detection in the Milky Way
Authors: Zhang Rui , Zhang Zhen
Published: June 2023

The origin and nature of dark energy is one of the most significant challenges in modern science. This research aims to investigate dark energy on astrophysical scales and provide a cosmology-independent method to measure its equation-of-state parameterw. To accomplish this, we introduce the concept of a perfect fluid in any static, curved spacetime, and express the energy-momentum tensor of the perfect fluid in a general isotropic form, namely Weinberg's isotropic form. This enables us to define an equation-of-state parameter in a physical and global manner. Within this theoretical framework, we demonstrate that the energy-momentum tensor of dark energy on different scales can take the general isotropic form. Furthermore, we explore the SdSwspacetime and establish its connection with dark energy in cosmology through the equation-of-state parameterw. In the SdSwspacetime, a repulsive dark force can be induced by dark energy locally. We then apply the concept of the dark force to realistic astrophysical systems using the Poisson equation. Finally, we find that an anomaly in the Milky Way rotation curve can be quantitatively interpreted by the dark force. By fitting the galactic curve, we are able to obtain the value of the equation-of-state parameter of dark energy, independently of specific dark energy models.
A thorough investigation of the prospects of eLISA in addressing the Hubble tension: Fisher forecast, MCMC and Machine Learning
Authors: Shah Rahul , Bhaumik Arko , Mukherjee Purba , Pal Supratik
Published: June 2023

We carry out an in-depth analysis of the capability of the upcoming space-based gravitational wave mission eLISA in addressing the Hubble tension, with a primary focus on observations at intermediate redshifts (3 < z < 8). We consider six different parametrizations representing different classes of cosmological models, which we constrain using the latest datasets of cosmic microwave background (CMB), baryon acoustic oscillations (BAO), and type Ia supernovae (SNIa) observations, in order to find out the up-to-date tensions with direct measurement data. Subsequently, these constraints are used as fiducials to construct mock catalogs for eLISA. We then employ Fisher analysis to forecast the future performance of each model in the context of eLISA. We further implement traditional Markov Chain Monte Carlo (MCMC) to estimate the parameters from the simulated catalogs. Finally, we utilize Gaussian Processes (GP), a machine learning algorithm, for reconstructing the Hubble parameter directly from simulated data. Based on our analysis, we present a thorough comparison of the three methods as forecasting tools. Our Fisher analysis confirms that eLISA would constrain the Hubble constant (H
0) at the sub-percent level. MCMC/GP results predict reduced tensions for models/fiducials which are currently harder to reconcile with direct measurements of H
0, whereas no significant change occurs for models/fiducials at lesser tensions with the latter. This feature warrants further investigation in this direction.
Updating constraints on phantom crossing f(T) gravity
Authors: dos Santos F.B.M.
Published: June 2023

We establish constraints on f(T) gravity by considering the possibility of a scenario
that supports a phantom crossing of the equation of state parameter ω
DE. After
determining the viable parameter space of the model, while checking the impact on the background
dynamics, we perform an analysis to obtain constraints on cosmological parameters and determine
the viability of this scenario. To this end, we use combined data sets from cosmic chronometers
(CC), baryonic acoustic oscillations (BAO), redshift space distortion (RSD) and Type Ia supernovae
(SN) measurements from the latest Pantheon+ set, in which the impact on the absolute magnitude
due to the change of the effective gravitational constant is also considered. It is found that a
state where a phantom crossing of ω
DE happens is favored by data, and the f(T) model
is competitive with the ΛCDM one by statistical criteria, such as AIC and
BIC. Additionally, we find evidence of the Hubble tension being alleviated within the f(T) 
model, at the same time that it does not worsen the growth one, indicating a possibility of the
present scenario as an option to address the current cosmic tensions.
W-doped In2O3 nanofiber optoelectronic neuromorphic transistors with synergistic synaptic plasticity
Authors: Yang 杨 Yang 洋 , Fu 傅 Chuanyu 传玉 , Ke 柯 Shuo 硕 , Cui 崔 Hangyuan 航源 , Fang 方 Xiao 晓 , Wan 万 Changjin 昌锦 , Wan 万 Qing 青
Published: June 2023

Neuromorphic devices that mimic the information processing function of biological synapses and neurons have attracted considerable attention due to their potential applications in brain-like perception and computing. In this paper, neuromorphic transistors with W-doped In2O3 nanofibers as the channel layers are fabricated and optoelectronic synergistic synaptic plasticity is also investigated. Such nanofiber transistors can be used to emulate some biological synaptic functions, including excitatory postsynaptic current (EPSC), long-term potentiation (LTP), and depression (LTD). Moreover, the synaptic plasticity of the nanofiber transistor can be synergistically modulated by light pulse and electrical pulse. At last, pulsed light learning and pulsed electrical forgetting behaviors were emulated in 5 × 5 nanofiber device array. Our results provide new insights into the development of nanofiber optoelectronic neuromorphic devices with synergistic synaptic plasticity.
A comprehensive review of recent progress on enhancement-mode β-Ga2O3 FETs: Growth, devices and properties
Authors: Li Botong , Zhang Xiaodong , Zhang Li , Ma Yongjian , Tang Wenbo , Chen Tiwei , Hu Yu , Zhou Xin , Bian Chunxu , Zeng Chunhong , Ju Tao , Zeng Zhongming , Zhang Baoshun
Published: June 2023

Power electronic devices are of great importance in modern society. After decades of development, Si power devices have approached their material limits with only incremental improvements and large conversion losses. As the demand for electronic components with high efficiency dramatically increasing, new materials are needed for power device fabrication. Beta-phase gallium oxide, an ultra-wide bandgap semiconductor, has been considered as a promising candidate, and various β-Ga2O3 power devices with high breakdown voltages have been demonstrated. However, the realization of enhancement-mode (E-mode) β-Ga2O3 field-effect transistors (FETs) is still challenging, which is a critical problem for a myriad of power electronic applications. Recently, researchers have made some progress on E-mode β-Ga2O3 FETs via various methods, and several novel structures have been fabricated. This article gives a review of the material growth, devices and properties of these E-mode β-Ga2O3 FETs. The key challenges and future directions in E-mode β-Ga2O3 FETs are also discussed.
Shear Strength Prediction of Reinforced Concrete Two-way Thick Slabs: Comparison between Experimental and Analytical Studies
Authors: Zufarihsan R , Tambusay A , Suprobo P
Published: June 2023

This paper describes an attempt to perform analytical studies on shear strength prediction of reinforced concrete two-way thick slabs. To this end, twenty test data from four groups of researchers were adopted and compared against the shear strength predictions from five shear design equations (i.e., ACI 318-14, ACI 318-19, EC2, CSA, and SMCFT). The ability of these equations to provide accurate prediction was evaluated based on the ratio of test-to-calculated shear strength, coefficient of variation (COV), and distribution of test data against the equality line. From the results presented, it was shown that each shear design prediction varied considerably from one another. Regarding the accuracy, it was shown that the SMCFT design method was able to predict the shear strength more accurately and proved the development of theoretically-sound shear design with a simple and straightforward procedure worked well in this case. It was also shown that improved prediction was able to be captured by ACI 318-19 compared to its preceding version of ACI 318-14. ACI 318-19 was also shown to demonstrate more conservative predictions which were more comparable to SMCFT.
An integrated approach for the strength evaluation on RC beams by the combination of hammer test and compression test
Authors: Hidayat B A , Ahyani A N
Published: June 2023

The structural performance of the old existing RC building needs to be evaluated, as it is susceptible to severe damage. There are two different types to examine the RC members’ capacity: the destructive and non-destructive tests, with their drawbacks and difficulties. The main purpose of this research is to establish the integrated approach to evaluating the compressive strength of RC beams by providing the strength distribution visualization. Hence, the combination of the results from the hammer test, compression test, and the two-point load flexural test was taken into account. In this study, a combination of destructive and non-destructive tests was performed on the RC beam specimen. The hammer test results discovered that the concrete strength was distributed randomly with a difference of 20%. However, the strength pattern in the compression zone showed similar results: a lower strength value. The abovementioned results were then validated with the flexural test. By comparing the concrete failure and the strength distribution visualization, the damaged area has a smaller compressive strength than other areas. Thus, the engineers could use the visualization of the strength distribution as a guide in considering repairing options on RC beams more effectively.
Comparison of flexural beam behavior due to monotonic loading and loading-unloading scheme
Authors: Indriyantho Bobby Rio , Purwanto  , Adhi Muhammad Zulfikar , Pandiangan Ricardo
Published: June 2023

Reinforced concrete is a construction material used frequently in Indonesia to build structural members especially beam structures. As one of the structural members, a beam should be able to carry flexural and shear loading as well as distribute the loading to the column and eventually to the foundation. In order to avoid structural failure in design, the reinforced concrete beam is continuously studied. This research investigates its behavior at monotonic loading and loading-unloading schemes. A point load was applied at the midspan of the simply supported beam. The result showed that the beam subjected to monotonic loading has a slightly overestimated value compared to the beam at loading-unloading condition The first crack load, the yielding load, and the ultimate load at monotonic loading were observed as 6.9%, 6.5%, and 8.2% higher than the result during loading-unloading situations. Crack patterns occurred at both monotonic loading and loading-unloading scheme equally showed that the beam experienced flexural failure. However, the crack at monotonic loading propagated more spread out than the crack happened during the loading-unloading scheme which was more concentrated at the plastic hinge located near the column.
The effects of various parameters in sensitivity analysis of plain concrete beam using rigid body spring model
Authors: Purnomo Joko , Han Aylie , Gan Buntara Sthenly , Hardjito Djwantoro
Published: June 2023

The Rigid Body Spring Model (RBSM) is an alternative method to Finite Element Model (FEM) to solve continuum problems in civil engineering. The method has three main advantages, i.e., having a smaller local stiffness matrix, the ability to directly simulate cracks, and independent formulation of element types. Although the method has been extensively used in studying the behaviour of concrete structures, specific research on sensitivity analysis of this method has not been done nor published. In this research, sensitivity analysis of plain concrete beam using the model is performed. The parameters to be considered are boundary size, boundary element type, number of elements, crack mesh refinement, number of stages, and the effect of half modelling. Based on the sensitivity analysis, optimum parameters were selected to calibrate the model to three plain concrete samples. The result suggests that modulus elasticity of cylindrical concrete under compressive test is to be reduced around 0.2 times for simulating beam under third point loading.
The influence of viscosity-modifying agent and calcium carbonate on 3D printing mortar characteristics
Authors: Antoni A , Adi N , Kurniawan M E , Agraputra A , Teopilus D , Pudjisuryadi P , Chandra J , Hardjito D
Published: June 2023

3D printing or additive manufacturing is an example of technology development in the construction sector. In 3D printing mortar, many things need to be considered regarding the characteristics of the mortar, such as workability, initial setting time, compressive strength, extrudability, and buildability. In previous studies, there were problems in the printing process, such as a lousy extrusion process and cracks in the 3D printing mortar sample. This study used calcium carbonate and a viscosity-modifying agent (VMA) to modify the mixture to achieve the desired characteristics. The extrudability and buildability were tested by observing the extrusion process and measuring the thickness and width of each layer printed. Based on the research, adding calcium carbonate and VMA can reduce workability and accelerate the initial setting time of the mixture. The use of VMA can reduce the compressive strength of the mixture. Using calcium carbonate and VMA can also increase the buildability of the mixture. From the compressive strength test, there was a decrease of 39.26% in the 3D printing mortar sample compared to the mortar cube sample. In addition, it was found that the 3D printing mortar is anisotropic, so the compressive force’s direction affects the compressive strength produced.
High early strength foamed concrete design for structural precast concrete
Authors: Bali Ika , Widjajakusuma Jack , Ng Gino Pranata , Tjahjono Ricky
Published: June 2023

Precast lightweight concrete with specific gravity between 1440 kg/m3 and 1840 kg/m3, and high early compressive strength is one of the alternative materials in responding to the large and fast demand for precast concrete, as well as being easy to transport. This study proposes high early strength foamed concrete as an alternative to precast lightweight concrete for residential construction. The background of this study is considering the limited literature reports related to research on precast foamed concrete for the application of building structural elements. The purpose of this study was to obtain high early strength foamed concrete for structural precast concrete with minimum characteristics, including initial compressive strength of 14 MPa at 3 days of age, 20 MPa of compressive strength at 28 days of age, and specific gravity of less than 1750 kg/m3. There are 3 types of foamed concrete was studied, namely normal foamed concrete, foamed concrete with LDPE, and foamed concrete with water substitution accelerator. Then, compressive strength testing was conducted on cylindrical specimens. The results showed that foamed concrete with 10% water substitution accelerator produced the highest values for the initial compressive strength of 3 days and 28 days of age, 21.64 MPa and 29.27 MPa, respectively, and the specific gravity of 1743 kg/m3.
Properties evaluation of cold mix asphalt based on compaction energy and mixture gradation
Authors: Wulandari P S , Tjandra D
Published: June 2023

Mix design for cold mix asphalt as a surface course has several factors to be considered, such as the traffic level and environmental condition. The compaction energy in mix design is related to expected traffic level. The choice of aggregate gradation is affected by the environment condition. Generally, there are two types of cold asphalt mixture, open graded and dense graded. The purpose of this study is to investigate the properties of cold mix asphalt surface course considering the compaction energy and aggregate gradation factors by laboratory experiments. The trial specimens were prepared with five different cationic emulsion bitumen contents for each type of mixture gradation at various compaction energy using Marshall compactor machine. The stability and volumetric properties of these specimens were measured by Marshall Test and then compared to the specified values. If the pavement is designed properly, dense graded cold mix asphalt could be used for surface course for medium and light traffic, while open graded mixture has potential application for heavy traffic. Over compaction could cause a greatly increased stiffness of mixture, which potentially lead to crack. Cold mix asphalt with different type of gradation needs different compaction energy to reach the best properties of mixture.
The effect of asphalt emulsion type on the characteristics of cold asphalt emulsion mixtures
Authors: Wulandari P S , Lovrecia K , Santosa F M , Welerubun G A
Published: June 2023

The need for road infrastructure continues to increase affecting the increase of hot asphalt mixtures. Hot asphalt requires a lot of energy to use because it goes through a heating process, so Cold Emulsion Asphalt Mixture (CAEM) is widely studied to be an eco-friendly alternative to hot asphalt mixtures. This study used a type of mixture IV Asphalt Emulsion Mixture with 4 types of emulsified asphalt, which are Cationic Slow Setting-1 hard (CSS-1h), Cationic Medium Setting-2 (CMS-2), Cationic Rapid Setting-2 (CRS- 2), and Cationic Quick Setting-1 hard (CQS-1h). The test was carried out using the Marshall Test method and the parameters value of each type of emulsified asphalt was calculated. The test results are compared with their characteristics to determine the most suitable type of emulsified asphalt for heavy traffic in Indonesia. The results showed that CRS-2 emulsified asphalt was not recommended because it had low stability and did not meet the parameter requirements. The use of CQS-1h is recommended because at an early age it can produce high stability value and meet all requirements.
Comparison of Asphalt Concrete-Wearing Course (AC-WC) characteristics using 60/70 asphalt penetration and Elvaloy modified asphalt
Authors: Lubis Adina Sari , Muis Zulkarnain Abdul , Irza Muhammad Hafiz
Published: June 2023

The performance of the asphalt mixture is affected by the asphalt characteristics and the gradation of the aggregate. Polymer-modified asphalt has been widely used to overcome road pavement damage such as cracking, spalling, yielding, and damage due to deformation due to grooves, curling, or rutting. Polymer-modified asphalt has been widely used, both from plastomers and elastomeric types. Elvaloy modification asphalt resulted from the conventional asphalt mixing process of 60/70 with Elvaloy additives from Dupont that are elastomer using RET (Reactive Elastomer Terpolymer) technology. This study aimed to compare the characteristics of the AC-WC mixture using 60/70 penetration asphalt and Elvaloy modified asphalt. The study began by making a paved mixture using 60/70 penetration asphalt with the middle-graded aggregate. The Elvaloy modified asphalt has three aggregate gradations: lower limit, middle, and upper limit gradation. Test objects were made as many as 156 test objects to obtain Optimum Asphalt Content (OAC) values, then using OAC values, made 36 test objects for the Marshall test; 4 test objects for Wheel Tracking Machine (WTM) testing. The Marshall and WTM tests determine the performance of 60/70 penetration asphalt and Elvaloy modified asphalt on the AC-WC mixture. The research results of the properties test showed that Elvaloy modified asphalt has a better penetration value, softening point and ductility than 60/70 penetration asphalt. Marshall’s test results provided the highest Stability and flow value in the Elvaloy modified asphalt mixture. From the results of the WTM test, only the middle grade of Elvaloy modified asphalt meets the specification.
The influence of low alkaline activator on the compressive strength and workability of geopolymer concrete
Authors: Romadhon Eri Setia , Antonius  , Sumirin
Published: June 2023

This paper presents the results of research on geopolymer concrete using a reasonably low alkaline activator. The key objective concerning this research is to investigate whether a low alkaline activator is still qualified to produce a concrete compressive strength that fulfills the structural requirements. The experimental program is carried out by making geopolymer concrete specimens, where the variables reviewed represented the amount of alkaline activator (4% and 5%), the ratio of alkaline activator to fly ash (AAS/FA) was 0.35, 0.4, 0.5, 0.6. The treatment temperatures of the specimens were room temperature (33°C) and 60°C. The experimental results of the compressive strength test have shown that the compressive strength of low alkaline geopolymer activator concrete still meets the requirements as a structural material (i.e. Indonesian Concrete Code). The weight of the resulting specimen is included in the category of normal weight concrete. The workability of geopolymer concrete with low alkaline activator tends to be better if the ratio AAS/FA also increases, but the compressive strength of concrete tends to decrease.
Embodied carbon dioxide of fly ash based geopolymer concrete
Authors: Setiawan Agustinus Agus , Hardjasaputra Harianto , Soegiarso Roesdiman
Published: June 2023

Concrete is one of the most widely used construction materials in most construction works around the world. Concrete materials are generally composed of several basic materials, namely Portland cement (OPC), coarse aggregate, fine aggregate and water as a cement reagent. However, in recent years, environmental issues have made concrete a material that is less friendly to the environment. This is due to the high CO2 content in the Portland cement (OPC) manufacturing process. Therefore, it is necessary to innovate to replace OPC materials with other materials that are more environmentally friendly. One of the substitutes for OPC is fly ash. Geopolymer concrete is a concrete material that has a cement content of 0%.From the results of these calculations, it can be seen that the amount of carbon contained in 1m3, normal concrete is 552.22 kg, while in geopolymer concrete it is 242.87 kg, or lower by 309.35 kg. This carbon emission calculation value is only based on the A1-A3 carbon factor value. This indicates that the use of geopolymer concrete can reduce carbon emissions by up to 56.02%.
Analysis of Geopolymer Mortar Compressive Strength Based on Fly Ash and GGBFS as Patch Repair Material
Authors: Karolina Rahmi , Tarigan Johannes , Hardjasaputra Harianto , Silalahi Roy Andre Daniel
Published: June 2023

Damages that often emerge in concrete include cracks, delamination, spalling, wear, fracture, porous, voids (perforated). These damages need to be repaired, one of which is by patch repair. With consideration of strength and frugality, a self-made repair material was developed using mortar as a base material, i.e., geopolymer mortar. Geopolymer mortar is a mortar with natural materials and materials that have a high content of silica oxide and alumina (such as Fly Ash and GGBFS) as a binder that must be activated with an alkaline activator in the form of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). The use of Fly Ash and GGBFS as a binder to replace cement in geopolymer mortar has a positive impact from an environmental point of view because it can reduce the use of cement and can reduce environmental pollution due to Fly Ash and GGBFS waste. In this research, the effect of variations in Fly Ash and GGBFS and variations in the molarity of NaOH on the compressive strength of geopolymer mortar were investigated, in order to obtain the optimum composition of the geopolymer mortar mixture that meets the requirements of compressive strength as a repair material. From the results of the research, the maximum compressive strength occurred in GF91 16 M mortar at 56 days of 73.77 MPa was obtained. Geopolymer mortar has a higher compressive strength and a cheaper price when compared to Sika Grout mortar so that the use of geopolymer mortar as a patch repair material is better than Sika Grout mortar in terms of strength and frugality.
The characteristic of very high-performance concrete (VHPC)
Authors: Shahib Al Bari M. , Agustin Andini Dwi , Ekaputri Januarti Jaya
Published: June 2023

A Very High-Performance Concrete (VHPC) has compressive strength in the range 120-150 MPa and high flowability. However, there is no VHPC mix as a repairing grout in Indonesia. This study presents the mix design of VHPC using Indonesian by-product materials to achieve compressive strength of 120 MPa. A sequence experimental method determined the suitable material to replace fine sand, ground quartz and superplasticizer. Then, the optimum mix design was tested with compressive strength, splitting tensile strength, slump flow, permeability, and shrinkage tests. In addition, the effect of 35 mm length hook-end steel fiber in the VHPC by 2% of volume was observed. The optimum mix design used cement, silica fume, and glass powder as binder with the ratio of 3:1:1. The ratio of sand and binder was 0.88. The water to binder ratio (w/c) was 0.11 using superplasticizer and accelerator which was kept on 4.3% of cement weight each. This mix design achieved a compressive strength of 128 MPa at 28th day. VHPC had high shrinkage whether volumetric or longitudinal. However, the steel fiber was able to restrain the shrinkage and increased the tensile strength. Nevertheless, the hook-end steel fiber is not recommended because its large size decreased the compaction and eventually decreased the compressive strength.
Compressive strength, porosity, and sorptivity of blended Palm Oil Fuel Ash (POFA) concrete containing silica fume in peat water
Authors: Olivia Monita , Utama Panca Setia , Supit Steve
Published: June 2023

Blended Palm Oil Fuel Ash (POFA) concrete has the potential for application in organic acid environments such as peat land. However, there is a need to improve resistance of blended POFA concrete using silica fume as a pozzolanic material. There are limited studies of the blended POFA admixed with silica for organic acid exposure. In this study, compressive strength, porosity, and sorptivity of blended POFA concrete admixed with silica such as silica fume has been investigated by exposing the samples in peat water. Portland Composite Cement (PCC) concrete with similar target strength was used as a control mix. The blended POFA concrete contained 0%, 20% and 40% POFA as a cement substitute. Micro silica or silica fume was added with concentrations of 10% in each mixture. Portland Composite Cement (PCC) with similar target strength was used as a control mix. The resistance of the POFA concrete specimens to organic acid attack were measured by compressive strength, porosity and sorptivity development at 7, 28 and 91 days. Compressive strength of control mix declined, while strength of PCC and PCC-POFA concrete containing silica fume increased at 91 days. Porosity and sorptivity of PCC and blended OFA concrete followed the same trend with the compressive strength. Thus, blended POFA concrete containing silica fume has better resistance in peat water than that of the control mix.
An overview of motivators and challenges of passive design strategies
Authors: Juffle Nor Aqilah Haji , Rahman Md Motiar
Published: June 2023

Growing concerns over high energy consumption and CO2 emissions from residential buildings have boosted the adoption of passive design strategies (PDS) globally, for their promising solution to address these issues, and also positively influencing occupant productivity. As such, many governments and organizations have developed relevant codes and procedures to encourage and enforce the adoption of PDS. Despite the increased focus, the adoption of PDS is still trailing behind in developing countries, particularly in a hot, dry and humid climate zone. This paper examines the current state of PDS adoption in such climates, and extracts relevant motivators, and challenges. The data was gathered through a structured review of literature. Initial results show the extraction of thirty-five motivators and forty-six challenges to PDS adoption. The key motivators include reduction in energy consumption and energy bills, while key challenges include high initial investment and lack of awareness. These are expected to generate a general awareness among stakeholders and allow a better understanding of the underlying issues for non-adoption of PDS. Future research will examine the extracted sets of motivators and challenges through a questionnaire survey in a hot, dry and humid climate zone.