bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micro-Raman analysis of HVPE grown etched GaN epilayer with porous formation
Authors: Posha Atheek , Padmanabhan Puviarasu , Basha S Munawar 
Published: May 2023

Abstract
The GaN epilayer grown by hydride vapor phase epitaxy was wet etched by phosphoric acid as the etchant. X-ray diffraction confirms that the GaN has a wurtzite structure. Scanning electron microscopy shows various sizes of hexagonal pits for different times of etchant reactions. Atomic force microscopy shows increase in surface roughness with different etchant rate. The photoluminescence gives a 3.4 eV luminescence for the pristine GaN epilayer. In the etched films, the deep-level defect belonging to yellow and green luminescence was found. The deconvoluted Ga 3d peaks of etched samples show Ga-rich epilayers. Micro-Raman spectroscopy is a non-destructive method for measuring carrier concentration, phonon lifetime and strain using A
1
(LO) spectra of Raman vibration mode was utilized via the Lorentz fitting method. The carrier concentration increases while the phonon lifetime decreases with etching rate. Overall, in the 9 min reaction, the epilayer was etched heavily with a perfect hexagonal etch pit structure.
A mechanical-free designing method for tailoring nonlinearity in bi-stable piezoelectric energy harvesters
Authors: Su Xukun , Leng Yonggang , Xu Junjie , Chen Xiaoyu , Sun Shuailing , Fan Shengbo 
Published: May 2023

Abstract
This paper presents a mechanical-free method for providing and tailoring the nonlinear force in bistable piezoelectric energy harvesters (BPEHs). The nonlinear force can be tailored to obtain a lower threshold for inter-well motions, or for the harvester to operate at various excitation levels and frequencies without changing the mechanical structure or the overall assembly. In BPEHs, the nonlinear force is tailored to match a specific excitation level and frequency, and the mechanical structure is designed to achieve higher strain (and thus higher output power). The design of nonlinearity can be separated from the design of the mechanical structure by using magnetic interactions. Hence, the design of nonlinearity is the arrangement of the external magnetic field of the harvester. In this paper, arranging the external magnetic field is achieved by arranging the magnetization distribution of one external magnet. With the locally demagnetizing technique, a uniformly magnetized permanent magnet can be locally demagnetized with desired patterns. The external magnetic field is provided by a locally demagnetized permanent magnet (LDPM). The nonlinear force can be tailored by simply altering the properties of the LDPM. This method converts the design of providing and tailoring the nonlinear force into the design of the LDPMs. For demonstration, we show that without increasing the distance between magnets, the potential barrier of the bistable system is dramatically reduced by using LDPMs. Melnikov’s method is utilized to show that the energy harvesters with LDPMs possess a lower threshold for homoclinic tangency than energy harvesters with a normal magnet. The influence of the parameters of the LDPMs on the energy harvesting performance is studied via simulations and experiments. Results show that without violating the mechanical part, changing the locally demagnetizing patterns can effectively change the harvester’s working frequency and excitation threshold.
Evaluation of Coronal and Interplanetary Magnetic Field Extrapolation Using PSP Solar Wind Observation
Authors: Song Yue-Chun 
Published: May 2023

Abstract
Using solar wind observation near PSP perihelions as constraints, we have investigated the parameters in various PFSS model methods. It is found that the interplanetary magnetic field extrapolation with source surface height R
SS = 2 Rs is better than that with R
SS = 2.5 Rs. HMI and GONG magnetograms show similar performances in the simulation of magnetic field variation, but the former appears to have a slight advantage in reconstruction of intensity while the latter is more adaptable to sparser grids. The finite-difference method of constructing eigenvalue problems for potential fields can achieve similar accuracy as the analytic method and greatly improve the computational efficiency. MHD modeling performs relatively less well in magnetic field prediction, but it is able to provide rich information about solar-terrestrial space.
First Detailed Photometric Investigation on the Nature of Contact Binary System AA Cet
Authors: Yıldırım M. F. , Soydugan F. 
Published: May 2023

Abstract
The TESS light curve (LC) of the marginal contact binary AA Cet was analyzed simultaneously with the radial velocity and the orbital period (OP) change of the system was investigated. The physical parameters of the system were obtained by analyzing the LC of AA Cet with the Wilson-Devinney method, and the absolute parameters of the components were calculated using the results obtained. For the components of AA Cet, the masses and radii were calculated as M
1 = 1.39 ± 0.04 M
⊙, M
2 = 0.48 ± 0.02 M
⊙ and R
1 = 1.64 ± 0.03 R
⊙, R
2 = 1.01 ± 0.04 R
⊙, respectively. AA Cet is a marginal contact binary with a temperature difference of 1305 K between its components. A total of 14 eclipse times were obtained from the TESS data and used in the OP analysis together with those collected from the literature. It has been observed that the change in the OP of AA Cet is in the form of a decreasing parabola. Conservative mass transfer between the components has been interpreted as the reason for this change. The OP decrease amount of AA Cet was obtained as dP/dt = 0.0062 ± 0.0006 s yr−1, and the reason for this decrease was attributed to a 3.3(9) × 10−8
M
⊙ mass transfer per year from the more massive component to the less massive one. The age of AA Cet has been estimated as 7 Gyr, as the age of contact systems helps us to understand their evolution.
Variable Star Detection in the Field of Open Cluster NGC 188
Authors: Song Fang-Fang , Niu Hu-Biao , Esamdin Ali , Zhang Yu , Zeng Xiang-Yun 
Published: May 2023

Abstract
This work presents the charge-coupled device (CCD) photometric survey of the old open cluster NGC 188. Time-series V-band photometric observations were conducted for ten nights in 2017 January using the Nanshan One-meter Wide-field Telescope to search for variable stars in the field of the cluster. A total of 25 variable stars, including one new variable star, were detected in the target field. Among the detected variables, 16 are cluster member stars, and the others are identified as field stars. The periods, radial velocities, effective temperatures, and classifications of the detected variables are discussed in this work. Most of the stars’ effective temperatures are between 4200 and 6600 K, indicating their spectral types are G or K. The newly discovered variable is probably a W UMa system. In this study, a known cluster variable star (V21=V0769 Cep) is classified as an EA-type variable star based on the presence of an 0.5 mag eclipse in its light curve.
Unveiling the Initial Conditions of Open Star Cluster Formation
Authors: Hao C. J. , Xu Y. , Hou L. G. , Lin Z. H. , Li Y. J. 
Published: May 2023

Abstract
Open clusters (OCs) are infrequent survivors of embedded clusters gestated in molecular clouds. Up to now, little is known about the initial conditions for the formation of OCs. Here, we studied this issue using high-precision astrometric parameters provided by Gaia data release 3. The statistics show that the peculiar motion velocities of OCs vary slightly from infancy to old age, providing a remarkable opportunity to use OCs to trace their progenitors. Adopting a dynamical method, we derived the masses of the progenitor clumps where OCs were born, which have statistical characteristics comparable to previously known results for clumps observed in the Galaxy. Moreover, the masses of the progenitor clumps of OCs indicate they should be capable of gestating massive O-type stars. In fact, after inspecting the observed OCs and O-type stars, we found that there are many O-type stars in OCs. The destructive stellar feedback from O-type stars may disintegrate the vast majority of embedded clusters, and only those sufficiently dense ones can survive as OCs.
Architectural Shape Optimization of Moving Dam on Rain River Downstream: An Ecosystem Cyclic Intervention
Authors: Samodra F X T B , Krisdianto J , Gunawan F C R , Alifianto H 
Published: May 2023

Abstract
Naturally, the downstream of the rain river experiences periodic floods and droughts. This process is beneficial for the distribution of dissolved nutrients and minerals. Moving dams or barrages are generally built to minimize disasters. Even though they can control floods and droughts, the existence of dams adds new problems to the ecosystem. The barrage limits the natural flooding process, resulting in an imbalance in the river ecosystem. This imbalance harms ecosystems, impacting humans who depend on rivers for water sources and livelihoods. From these problems, the proposed design concept of a sustainable architectural dam through consideration of the design of the form, facade, aesthetics and the balance of the river ecosystem and humans on the Sembayat Barrage of Bengawan Solo River, Gresik Regency, Indonesia, as moving dam case. This concept collaborates the principles of architectural ecology and architectural biomimicry to produce a dam design that is friendly to the river ecosystem, including humans. In making it happen, Ansys tools are used to detect potential wind movement, and Fusion is used to maximize the structure with shape optimization. The design results obtained are in the form of a redesign of the dam by maximizing the downstream potential of the river while paying attention to the downstream river ecosystem through an architectural approach.
Pre-evaluation and visual simulation of energy consumption influencing factors of smart and healthy architecture in the design stage
Authors: Teng Xiao , Shen Zhenjiang , Xixi Wei , Tri Nguyen 
Published: May 2023

Abstract
This research aims to carry out energy simulation of various setting factors of office space in smart and healthy architecture in the design stage. First, we established an office model based on Japanese architecture energy efficiency standards; then, we simulated the energy consumption process by setting reasonable factor parameters by utilising Openstudio; finally, the main factors contribute to energy consumption level of the office space and its energy saving potential were explored. Taking Hokkaido, Japan, as an example, by simulating the three major factors of smart and healthy architecture: smart devices, architecture materials, and human behaviour schedule, the effect of energy saving is calculated in the architectural design stage.
Energy Efficient Features of Vernacular Houses in Tropical Hilly Area of Indonesia
Authors: Fitriaty P , Zubaidi F , Masiming Z , Bassaleng A J R , Burhany N R , Syahrullah M R , Alfani  
Published: May 2023

Abstract
Energy efficient building is one of the alternative solutions to overcome the rapidly increasing use of energy consumption by the building sector. Traditional or vernacular houses rarely use mechanical means to create a comfortable living environment. Thus, the electrical energy consumed by traditional or vernacular houses was relatively low. It is believed that energy efficient features can be found in vernacular houses. Thence, this study explores the energy efficient features of vernacular houses, with a case study in the hilly area of the tropics, Palu-Indonesia. Field studies were conducted. Six vernacular houses were chosen purposively as the study samples based on building orientation, building form, roof form, wall construction, and type of opening. HOBO H21 and U12-012 were utilised to measure the internal and external air temperature, relative humidity, light intensity, wind speed and wind direction. The study result indicates that the sample houses’ thermal condition was slightly better than the external thermal condition. Sample 1 can modify the external air temperature up to 42.8 K during the daytime. The light condition, in contrast, showed poor performance. Thus, more transparent material with proper shading was needed to succeed daylighting in the buildings’ interior. Several energy efficient features of vernacular houses found in the samples are as follows: shallow building plan elongated to East – West, building geometry, resistive building materials, the use of ceilings, and side-hung or jalousie type of windows with an adequate size of the effective opening for ventilation and lighting.
The Properties of Liquefiable Soil with Swedish Weight Sounding Test in BPTB (Agricultural Technology Research and Development Center) Office, Central Sulawesi
Authors: Setiawan H , Jureje U 
Published: May 2023

Abstract
An earthquake measuring 7.4 MW in Central Sulawesi on 28th of September 2018, triggered liquefaction in several locations, one of them namely the BPTP office in Sigi district. The liquefaction that occurs causes massive sand boiling around the building, and a settlement in the foundation. This study aims to determine and compare the properties of land affected and not affected by liquefaction based on the Swedish weight sounding test, as well as the potential for liquefaction at the BPTP office location. The study consisted of 2 testing methods, namely field testing was carried out using the Swedish weight sounding test equipment at 3 points on the affected soil and 3 points on the unaffected soil, and laboratory testing including sieve analysis testing and Atterberg limits for 18 soil samples. The results showed that the Nsw value on the affected soil is in the range 4.00 n/m - 238.10 n/m, the Nsw value on the unaffected soil is in the range 26.00 n/m - 303.03 n/m, and groundwater level data obtained from the JICA Survey for Disaster Information Collection in Indonesia 2020 is at a depth of 5.31 meters below ground surface. The first section in your paper
Geological Structure Control of The Distribution Quartz Vein as Mineralization Pathway In Kawatuna Area, Palu City Indonesia
Authors: Assidiqi M , Asrafil  , Puspita R , Mukaddas A 
Published: May 2023

Abstract
The Kawatuna area has a complex geological structure condition and is estimated to be a weak zone for hydrothermal solutions to rise and then accumulate into deposits in the form of veins. Based on this, it makes this area interesting to study. This study aims to determine the condition of the geological structure and its influence on the condition of the distribution of veins in the study area. The method used is surface geological mapping and geological structures analysis. Based on surface geological mapping, it was found that the study area was composed of schist rock units, gneiss, granodiorite, and molasses units. The geological structure that developed in the study area consisted of shear joints in the form of systematic and non-systematic shear joints and shear faults. The distribution of quartz veins in the study area has a general direction of northwest-southeast and northeast-southwest. The presence of mineralization in the form of quartz veins in the study area is strongly controlled by the presence of geological structures that form an oblique convergence fault model that shows a dilatational movement force. The deposit opening system formed in the study area is a jog deposit system in which pull-apart basin fracture arrays develop which are characterized by the presence of tension fractures/veins.
Water absorption of ambient-cured geopolymer concrete
Authors: Adam Andi Arham , Deviana Lilis , Siregar Atur PN , Mustofa  
Published: May 2023

Abstract
This study aims to determine the effect of the activator-binder ratio on the water absorption of ambient-cured geopolymer concrete. Class F fly ash from Mpanau power plant was used as precursor. This raw material was activated by a mixture of sodium silicate and sodium hydroxide solution, with an activator-binder ratio of 0,45; 0,50; 0,55; 0,60. Five percent replacement of fly ash by slaked lime was added to achieve ambient curing. The test specimen for the absorption test is made in the form of a cylinder with a size of 100 mm dia x 100 mm height. The absorption test used ASTM C642-06, and the test was conducted at the age of 28 days. The test results show that the geopolymer concrete with the largest activator/binder ratio has the lowest absorption, and volume permeable of voids. In this research, it was found that for the geopolymer concrete, activator-binder ratio of 0.60 has the lowest absorption and volume of permeable voids but gave the highest compressive strength. In addition, the test results show that normal concrete has the highest absorption and volume permeable of voids compared to the geopolymer concrete
Using Space-L complex network model for public transportation supply and demand analysis in Taipei metropolitan area
Authors: Wang Junye , Pai Shin-En , Pai Jen-Te 
Published: May 2023

Abstract
As an important means of transportation in modern cities, public transportation plays an important role in people’s travel and the economic development of urban areas Harvey 1971 [1]. Many researchers apply the complex network theory to urban public transport network, construct complex networks and view the operation of urban public transport from the perspective of complex networks. The study established a complex network model of BUS, MRT (metro), LRT (light rail) and Multi-vehicle. And based on the weighted analysis of the actual passenger traffic, the weighted complex network model which conforms to the actual travel characteristics is obtained, and the relationship between the public transport station and the surrounding land use in Taipei metropolitan area is discussed.
Study Of Sustainable Palu-Koro Geotourism In The Palu Valley
Authors: Rizkhi  , Mulyati Sri , Takwim Supriadi , Kurniawan M. 
Published: May 2023

Abstract
To enrich the principle of sustainability through the development of the geographical character of the area along the Palu-Koro Fault as a tourism destination, conservation activities, education, and improvement of the local economy are carried out while still maintaining the carrying capacity of the environment. This study explores the peculiarities of geology, beauty and environmental diversity as potential heritage of Palu-Koro geotourism, so that it is feasible to develop sustainable geotourism in the Palu valley. An exploratory descriptive approach is used to find the formulation of area management from the potential of heritage and geological sites, the need for tourism components, and tourism products. The components studied include Geology and Sustainability. The results show that the condition of the geological sites formed after the 7.4 Richter Scale tectonic earthquake activity is mostly still natural and has not been managed properly. After four years of the disaster, the condition of the Petobo liquefaction area, the post-tsunami coastline, and the Diponegoro fault are all filled with shrubs and liquefaction and tsunami soil deposits, while building fossils still exist.. Therefore, a study is needed that pays attention to the location of the site and post-disaster spatial directions in the Disaster-Prone Zone.
Time Series Modeling on Daily Streamflow in a Lack-Data Catchment
Authors: Tunas I G , Herman R. , Arafat Y. 
Published: May 2023

Abstract
The limited time series data for daily discharge to support the development and management of water resources in a catchment is a classic challenge in hydrology. Various methods, both empirically and conceptually based, have been developed to overcome this problem. This paper presents a time series modeling of daily discharge in relation to the scarcity of discharge data in Sausu Catchment, Central Sulawesi, Indonesia. The simulation has been assigned to the HEC-HMS Model with the input of daily rainfall data for the period 2018-2020 and potential evapotranspiration data. Before this stage is executed, optimization has been performed to determine 17 optimal parameters representing three methods in three sub-models with input data pairs ranfall-discharge in November 2017. Optimal parameters have been achieved at RMSE 10.3, with 2 parameters unchanged. The simulation results indicate that the daily flow of the Sausu River based on daily rainfall data for three years varies in the range of 8 m3/s to 160 m3/s. This trend of time series data flow tends to be associated with daily rainfall data as input.
Geology and Groundwater Quality Analysis for Clean Water and Irrigation of Sanga-sanga District, Kutai Kartanegara Regency, East Kalimantan Province
Authors: Nugrah Nurhasimah , Syam M A , Heriyanto  
Published: May 2023

Abstract
The research locations are in two sub-districts, namely Sanga-Sanga District, Samarinda City and Palaran District, Kutai Kartanegara, East Kalimantan Province The research method used in this study is geological mapping, then laboratory analysis. The well water sample data used is 2 sample water which is considered to represent the research area. Geological conditions in the study area there are 3 rock units where the rock units of the oldest are the Sanga-sanga sandstone unit, the Bantuas sandstone unit and alluvial deposits. For geomorphological units, it is divided into 6 forms, namely the eroded hill unit, the remaining hill, the Alluvial Plain, swamp, river body, disposal and mine opening. Based on the results of the piper diagram analysis Groundwater is included in the type of magnesium bicarbonate with carbonate hardness (secondary alkalinity) > 50% groundwater is dominated by alkaline soil (Ca + Mg) and weak acids (CO3 + HCO3), and based on the results of the stiff diagram analysis, the research area is included in the type of calcium carbonate (CaHCO3) and Magnesium Carbonate (MgHCO3). The assessment of groundwater quality for irrigation purposes concluded that the analyzed sample could be used as irrigation water.
The flexural strength of green foamed concrete with polypropylene fiber
Authors: Qubro K Al , Saggaff A , Saloma  
Published: May 2023

Abstract
Green concrete is made from eco-friendly waste materials. It reduces CO2 emissions and reduces water use. Normal concrete contributes about 40-50% of carbon in the air due to its production, impacting climate change. The waste material from coal combustion, like fly ash used as an additive to replace some cement in the concrete mixture. Foamed concrete is considered concrete with an eco-friendly material because it uses less aggregate and reduces water use. Concrete is weak to tensile forces; adding Fly ash can reduce pores allowing acidic substances to enter. Adding polypropylene fiber to prevent cracking makes foamed concrete more ductile. Green expanded concrete contains 0.8% foaming agent, with polypropylene fiber (PPF) variants of 0.15%, 0.2%, 0.3%, and 25% fly ash as a cement alternative. The findings of the flexural strength test demonstrate that fibers added to green foam concrete boost its flexural strength. Green foam containing polypropylene fibers produces a maximum flexural strength of 0.3% higher than green foam concrete without fibers.