bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and finite element analysis of Cu and Nb severely deformed by 3-axis forging
Authors: Carnrike T , Bembridge N , Afangideh C , Kalu P N 
Published: August 2019

Abstract
The evolution of microstructure during 3-Axis Forging (3AF) of OFHC Copper and RRR Niobium has been investigated using both experimental and numerical simulation techniques. The finite element analysis (FEA) aspect was carried out using DEFORM, a commercial software. The 3AF process was conducted at 25° C with a cross-head speed of 0.015 mm s−1 and a strain per pass of 0.2. Vickers hardness testing and orientation imaging microscopy (OIM) showed that the evolution of microstructure during 3AF can be classified into three regions: At low strain, region I, in which the high angle grain boundary percentage (HAGB%) declines due to the increase in low angle grain boundary (LAGB) resulting from dynamic recovery. At intermediate strain, region II, there is a progressive increase in HAGB%, due to the conversion of most of the LAGB to high angle grain boundaries (HAGB). This is followed by region III, in which the HAGB% remains relatively unchanged due to a stable microstructure formed by continuous recrystallization. Assessment of the grain size revealed that refinement occurred in regions I and II, resulting in a final grain size of about 2.0 μm and 1.4 μm in Cu and Nb, respectively. Flownet analysis of the first two cycles showed that four deformation zones similar to the hardness pattern were developed in both materials during the 3AF. These zones correlated well with the effective strain and hardness distributions. The highest effective strain and hardness were found in the core of the material (zone A), while the least hardness developed at the edges (zones C and D).
Miniature tensile testing of SPD processed fine-grained aluminum
Authors: Lanjewar Harishchandra A , Naghdy Soroosh , Kestens Leo A I , Verleysen Patricia 
Published: August 2019

Abstract
Manufacturing of ultrafine-grained (UFG) or nanocrystalline (NC) metals via a single step top-down approach imposing severe plastic deformation (SPD) is one of the most promising ways to achieve superior properties such as high strength and superplastic forming capability. Nonetheless, the lack of relevant data on their post-SPD performance in different test environments makes it difficult to fully understand their mechanical behavior. While characterizing the tensile behavior, almost all of the previous reports are limited to the discussion on the plastic performance of the material in terms of elongation to failure and corresponding strength, with only a few studies discussing the effect of grain fragmentation on work hardening response of the material. In the present work, a comprehensive analysis is presented in terms of the uniform and post-necking mechanical behavior of the ultrafine-grained material. Commercially pure aluminum is subjected to high pressure torsion (HPT) deformation with strains ranging from very low levels (γ ≈ 2.1) to values well in the saturation regime (γ ≈ 25.1). When tested in uniaxial tension, the strength increases monotonously. The uniform elongation improves with the imposed HPT strain, though remains lower than the value of the initial material. Based on the slopes of the stress-strain curve, three distinct zones are identified, i.e. uniform deformation, post-necking-1, and post-necking-2. With accumulating SPD deformation, the material shows enhanced pre-necking strength and ductility; while post-necking material fails early and at lower strength levels. The post-necking response is observed to be highly microstructure dependent: a lower grain size augments the resistance for micro-crack propagation and thus the ductility, however, once initiated, a crack propagates much faster in fine-grained than in coarse-grained HPT processed material.
Comparison between experimental data and a cellular automata simulation of martensite formation during cooling
Authors: Kaijalainen A , Seppälä O , Javaheri V , Pohjonen A , Porter D , Kömi J 
Published: August 2019

Abstract
Computer simulations of steel microstructural development provide a powerful tool, which can form the basis of mechanical property predictions. However, in order to create detailed understanding of the factors affecting the properties, the model should predict microstructural evolution during cooling. The present study compares the results of cellular automata simulations with experimental data for two distinct austenite conditions, recrystallized and deformed. Detailed microstructural features were studied using a laser scanning confocal microscope, FESEM and FESEM-EBSD. The two-dimensional cellular automata (CA) model for simulating the formation of lath martensite was parameterized using fitted Johnson-Mehl-Avrami-Kolmogorov and Koistinen-Marburger equations. The parent austenite microstructure for the CA model was determined from the final martensitic microstructure using austenite grain reconstructions based on the use of MATLAB software and the MTEX toolbox. The results of this cellular automata simulation can be used to estimate the shapes and sizes of martensite blocks, which offers new possibilities for the qualitative estimation of the mechanical properties of high-strength steels formed from recrystallized or deformed austenite.
Evolution of microstructure, texture and grain boundary character distribution of potassium doped tungsten fibers annealed at variable temperatures
Authors: Tanure L , Terentyev D , Riesch J , Verbeken K 
Published: August 2019

Abstract
The effect of the annealing temperature on the microstructure and grain boundary character distribution of potassium doped tungsten fibers made of drawn wire was investigated by Electron Backscatter Diffraction. Samples, with a diameter of 148.7 μm, in the as-received condition and annealed at 1300, 1600, 1900, 2100 and 2300 °C were analyzed at the center of the transversal sections. Up to 1900 °C, a uniform microstructural coarsening and primary recrystallization followed by normal grain growth was observed. Between 1900 and 2100 °C abnormal grain growth took place. The strong texture (<110> parallel to the drawing axis) remained present in all conditions. With increasing the annealing temperature, the low angle grain boundary fraction increased at the expense of high angle grain boundaries while the amount of coincidence site lattice boundaries reached its maximum at 1600 °C. At this temperature, the most resistant configuration of triple junctions against intergranular crack propagation was obtained.
Static recrystallization of pure titanium after cryo-deformation
Authors: Yan C K , Cui G R , Qu S J , Feng A H , Shen J , Chen D L 
Published: August 2019

Abstract
Commercially-pure (CP) titanium was first processed via cryogenic deformation to activate high-density deformation twins, and was subsequently annealed at 500°C to induce static recrystallization (SRX). Two types of twins were mainly activated during cryogenic deformation, i.e.,

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contraction twins and

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extension twins. Multiple point-like twins were also present because the growth of twins was remarkably impeded at the low temperature. During annealing the recrystallization mechanisms were identified to be

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and

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twinning induced SRX. The point-like twins could effectively promote the occurrence of SRX. The grains were significantly refined from ∼40 to ∼2.7 μm while a few

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and

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TBs still retained with the same twinning angle/axis relationship during annealing.
Effect of Ca concentration on Microstructure formation behaviors in AZ61 magnesium alloy
Authors: Kim K , Han D , Kim K 
Published: August 2019

Abstract
Magnesium alloys have been paid attention as lightweight materials in various industrial fields. However, their use is limited by poor formability at room temperature which was caused by the limited number of slip systems. The texture control plays an important role in plastic workability of magnesium. Addition of Ca as alloying element is known to improve the general corrosion resistance and mechanical integrity of magnesium alloys in chloride environment. In order to investigate the Ca concentration on microstructure formation behaviors, Ca addition on AZ magnesium alloy were experimentally investigated by high-temperature uniaxial compression. Uniaxial compression test was conducted at 673K and 723K with a strain rate of 5.0×10−2s−1. The working softening was observed and the main component of texture and the sharpness of basal texture in two kinds of specimens varies depending on the deformation conditions.
The effect of abrasion on geomorphology changed and coast line conservation effort in Karawang Regency
Authors: Ihsan I F , Pin T G 
Published: August 2019

Abstract
The coastline in Karawang Regency stretches 84.23 km in nine sub-districts. One potential disaster is abrasion. The losses caused by abrasion have had an impact on public facilities and residents’ housing due to changes in coastlines and mangroves in Karawang District. The study aimed to obtain the distribution of abrasion along the Karawang coast and geomorphological changes that occurred from 2013-2018. The data used are Landsat Landsat 8 OLI satellite images and field surveys. The method used to analyze the rate of abrasion was carried out by spatial-temporal analysis for five years. Abrasion that occurred from 2013 - 2018 found in Pakisjaya, Cibuaya, Pedes, Cilebar, Tempuran, Cilamaya Kulon and Cilamaya Wetan Subdistricts. The efforts that have been made by the community in Cilamaya District are to conserve by planting mangroves and artificial barriers to the waves.
Analysis of spatial distribution of habitat oncomelania hupensis using landsat etm data in Lindu plain, Central Sulawesi
Authors: Kurniawan Muhamad , Supriatna  , Dimyati Muhammad 
Published: August 2019

Abstract
Transmission Schistosomiasis Japonicum, parasite disease by Schistosoma worm infection is closely related to the distribution of slugs Oncomelania Hupensis Linduensis. Spatial deployment of snail habitats can be traced through the geographical characteristics of their lives. This research was conducted to build spatial analysis model of the distribution of snail habitat using Landsat data to extract vegetation index information (NDVI), land humidity index (TVDI), land cover, with data supporting land inclination, altitude, distance from the river, distance from the lake, soil surface, and rainfall. Research conducted in the Lindu Plains was analyzed by stepwise regression to identify the ecological determinants of Oncomelania Hupensis Linduensis life. The results show that TVDI, land coverage, NDVI, and LST are the most significant variables with 85.9% correlation and 87.03% accuracy. From the modeling analysis, it is known that Oncomelania Hupensis habitat distribution shows a random pattern. By knowing the characteristics of Oncomelania Hupensis habitat distribution through remote sensing analysis, it is expected to monitor the movement of the habitat, so that the step can be used to help control the habitat referred to as host of Schistosomiasis disease in Indonesia.
Core laboratory measurements of ultrasonic tomography using the robot RTDs-U100 magnetic
Authors: Setiawan T , Fatkhan  , Cysela R Y , Rahadi A A , Sari V M 
Published: August 2019

Abstract
Along with the rapid development in technology, geophysical methods emerge as one of the research alternatives. Some research requires non-destructive test to determine characteristics of an object without causing any damage, such as core rock samples. Ultrasound tomography is non-destructive methods that reconstructing cross-sectional image of the internal structure of an object by analysing the propagation of ultrasound wave. The conventional method to measure core samples that usually use for determining the position of transducer and receiver sensors is by dragging manually. This manual measurement have weaknesses in terms of efficiency and accuracy. In this research, we design prototype of the Robot RTDs-U100 to improve the quality and efficiency measurements of core samples. The magnetic sensor used to control the rotation of transducer and receiver sensors. With this robotic rotation, the position of sensors is more precise and it takes less time. Our findings of core laboratory measurements show that Robot RTDs-U100 improved measurement error from 0,32% with manual measurement to 0,12% after using Robot RTDs-U100.
Geophysical approach to improve well correlation and stratigraphy package in the frontier area: example case of Upper Jurassic Fm. Semai Basin, Eastern Indonesia
Authors: Nainggolan H B , Winardhi S 
Published: August 2019

Abstract
Well correlation needs to be done carefully in the exploration phase. In this study, due to a limited biostratigraphy data, the alternatives approaches to improve the well correlation were conducted. The approach is known as an Integrated Prediction Error Filter Analysis (INPEFA). The method generates a predicted Gamma Ray (GR) log based on the auto-regressive model. INPEFA generate and extract major sequence information curve and give the clue to the interpreter to get the general frame of correlation. INPEFA curve idea is related with sedimentation cycle where the package of sediment consists of para-sequence set and the para-sequence is formed by lamination, and so on. This phenomenon is known as an order of sequences. For the case study, the method is applied in to the frontier block located in Semai basin in the eastern of Indonesia. Six wells are included in to the analysis to be correlated by combining limited biostratigraphy data and INPEFA curve. The results conclude that the correlations from five wells have identical of eustasy cycle pattern, and validated by biostratigraphy marker. The correlation also show that the thickness of reservoir sandstone in the Upper Jurassic Formation increase to the north direction.
Subsurface Modeling Based on Gravity Data of Rendingan-Ulubelu-Waypanas (RUW) Geothermal Field, Lampung, Indonesia
Authors: Widya Permatasari Ana , Santoso Djoko , Setianingsih  
Published: August 2019

Abstract
Indonesia is located along the archipelago which has abundance of volcanoes along the arc. Therefore, Indonesia has a very high geothermal energy potential, such as the Rendingan-Ulubelu-Waypanas Geothermal Field in Tanggamus Regency, Lampung Province. Geophysical exploration is required to characterize the subsurface geothermal system. One of the methods that can be used is gravity method. The data used in this study is an analog Rendingan-Ulubelu-Waypanas Geothermal Field Complete Bouguer Anomaly Map of 2005. The analog map was then converted into digital map for further data processing. Separation of regional and residual Bouguer anomalies has been performed using moving average and spectral filter methods, in which the spectral analysis was conducted in 1D and 2D. The value of Bouguer background density used for 2.5D subsurface modeling is 2.67 g/cc. The gravity anomalies obtained in this study can be interpreted as follow. The existence of high anomalies under Mount Waypanas was interpreted as a Tertiary intrusion of granite with a density contrast of 0.22 g/cc. While low anomalies in the northern part was interpreted as a Quaternary intrusion of diorite with a density contrast of -0.22 g/cc, which acts as the heat source of the system. The reservoir of the system is the Quaternary young volcanics exposed on the surface with averaged thickness of 1500 m. We concluded that the fluid flow in this geothermal system is the meteoric water from Mount Rendingan and Mount Tanggamus, which has a higher topography, flows to a lower topography area in the Mount Waypanas, The fluid flow also creates an upflow under Mount Rendingan.
A Non-Linear Method for Hypocenter Determination around Central and East Java Region: Preliminary Result
Authors: Muttaqy Faiz , Dian Nugraha Andri , Puspito Nanang T , Supendi Pepen , Rosalia Shindy 
Published: August 2019

Abstract
Java Island is highly active tectonic zone and also has a complex geological system as a result of Indo-Australian plate that subducted under the Eurasian plate. This complexity produces many large and destructive earthquakes. Moreover, Java is a most densely populated region in Indonesia. The precise earthquake location can define and evaluate the seismic hazard in the area. In this study, we determined hypocenter location around the central and east Java region by using a non-linear method. We manually picked P-and S-wave arrival time recorded by BMKG network for the time period of 2009 to 2017. We used the minimum 1D seismic velocity model of ak135 to locate the events. We used some criteria for the determination of event location including (i) at least recorded by 4 station which has clear onset P and S arrival, and (ii) has magnitude (MW) > 3. The seismicity in the study area is controlled by subduction and many active faults distributed along the Java Island, also clustered in several areas such as Kendeng thrust, Opak river fault, Kebumen, Banyuwangi, and others. The result of this study indicates the accurately main shallow seismicity zones in central and eastern part of Java region, and also confirm the presence of active inland faults. As further studies, we will conduct 1D velocity modeling and relocate the hypocenters using an updated local 1D velocity model beneath the study area.
Characterization of Volcanic Ash From the 2017 Agung Eruption, Bali, Indonesia
Authors: Devi S , Bijaksana S , Fajar S J , Santoso N A 
Published: August 2019

Abstract
In 2017, Mount Agung in Bali, Indonesia erupted after 54 years of dormancy. This eruption produced large amount of ash causing disruptions in this major tourist destination. Scientifically, however, this eruption produced important research material (volcanic ash). In this study, volcanic ash samples from 2017 Mount Agung eruption is subjected to geochemical and magnetic analyses, to gather information regarding the magmatic processes beneath Mount Agung. Samples were collected from four locations of varying distances. Magnetic analyses include measurement of magnetic susceptibility and hysteresis parameters, while geochemical analyses were carried out to determine the composition of major elements. These analyses are supplemented by petrographic analyses. Preliminary results show that the magnetic susceptibility values of the samples vary from 778 to 1002 × 10−8 m3/kg, the grain type is non-SP until the SP and non-SP grain mixtured, and the magnetic domain is the PSD and SP which differ significantly different from that of volcanic ash samples from other volcanos (Kelud, Sinabung, Soputan, Bromo, Merapi, Slamet) reported by previous studies. The results signify the potential use of rock magnetic methods combined with geochemical and petrographic analyses in characterizing volcanic ash.
Application of Refraction Seismic Tomography Method Using Wavepath Eikonal Traveltime Inversion for Modelling the Subsurface
Authors: Nurul Nida Hashina , Asta Yogantara Made , Otolomo Munawir A. P. , Sanny Teuku A. 
Published: August 2019

Abstract
Refraction seismic tomography is a geophysical method that is able to image shallow subsurface velocity variation. Common application of this method is for Civil Engineering include near-surface problem such as weathering zone and bedrock. In this study, refraction seismic tomography was using Wavepath Eikonal Traveltime (WET) inversion. This method is performed by software RayfractTM. The initial model is generated by Delta-t-V method and smoothing inversion. The Delta-t-V method obtain a 2D initial model, while the smoothing inversion obtain a 1D initial model. The forward modelling is done by finite-difference solution using Eikonal equation to obtain the ray tracing. Then WET inversion will obtain the subsurface model. The imaging result is able to show the thickness of weathering layer and the depth of the bedrock. The tomographic interpretation indicates the thickness of weathering layer is 2-10 meter, while the bedrock presence at depth 7-35 meter from the surface.
Teleseismic body wave inversion in determining rupture process of Sumbawa doublet earthquake, November 25th, 2007
Authors: Ratna P N , Gusman A R , Nugraha A D 
Published: August 2019

Abstract
The rupture patterns of the Sumbawa doublet earthquake that occurred on November 25th, 2007 was estimated using teleseismic body wave inversion. The first event occurred at 16:02:18 UTC with epicenter at 8.292°N and 118.37°E, short after this, the second event occurred at 19:53:08 UTC with epicenter at -8.224°N and 118.467°E. For each event, teleseismic body wave data were retrieved from the Incorporated Research Institutions for Seismology – Data Management Center (IRIS-DMC). The waves were windowed for 70 s which started at 20 s before the P-wave arrival, band-pass filtered between 0. 01 and 0.1 Hz and then integrated into a displacement with a sampling time of 0.5 s. The Green’s function is calculated using the Kikuchi and Kanamori method. The fault geometry is based on the earthquake parameters of the Global Centroid Moment Tensor solution. Strike and dip for first event were 88° and 23°, respectively and those for the second event were 87° and 25°, respectively. The seismic moment (Mo) estimated by the inversion for the first event is 0.617×1019 Nm or equivalent to moment magnitude (Mw) 6.46 with source duration of approximately 55 s. While for the second event, the seismic moment is estimated to be 0.644×1019 Nm (Mw 6.47), with slightly longer source duration. The inversion for both events provided a similar slip pattern. The rupture propagated along the dip direction, and the maximum slip occurred near the hypocenter region. The maximum slip amount for first event and second event were 1.43 m and 1.48 m, respectively.
Inversion Modelling 3D Gravity for Hydrocarbon Identification at Sanggau, West Borneo
Authors: Muhammad Indragiri Noor , Sumarni  
Published: August 2019

Abstract
Inversion modelling 3D in gravity is applied on Sanggau Quadrangle, West Borneo. Subsurface modelling by gravity methods has ambiguity, to solve this ambiguity invers modelling 3D has been applied to anomaly bouguer map with measurement of depth by spectral analysis. Invers modelling 3D use inversion method of singular value decomposition (SVD) and inversion Occam. Anomaly bouguer show low anomaly between -83.5 mGal to 184 mGal in the north and south of map, middle anomaly between 184 mGal to 315 mGal in the middle of the map, high anomaly has values between 346.5 mGal to 544.7 mGal in North-East. Spectral analysis have result of the regional depth 30.381 km. Invers modelling 3D has result the model that have RMS 0.063 and 0.02. Invers modelling 3D shown large thickness of sandstone with density 2.35 g/cc at Kayan High Land, Ketungau Low Land, and Kapuas Low land, that potential for hydrocarbon. Volume sandstone on Sanggau is predicted about ≤ 50892.19384 km3. The result of the model give preliminary information of model concept on estimated potential hydrocarbon.