bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite Element Modelling and Model Updating of Riveted Joint Structure
Authors: Shah M A S Aziz , Yunus M A , Rani M N Abdul , Zulkofli M. A.
Published: August 2019

Nowadays, the applications of rivet joints are dramatically increasing because of its capability and efficiency to assemble the engineering structure such as aerospace and mechanical structures. However, every joint such as riveted joint has a significant effect to the overall dynamic behaviour of the assembled structure. This is because, the overall dynamic behaviour of the assembled structure is highly relying on the quality of the riveted joints. Generally, the riveted joints always introduce local effects such as surface contact, clamping force and slip to the surface of the assembled structure. Therefore, this paper is attempted to investigate the dynamic behaviour of the riveted joints structure experimentally and numerically. The experimental modal analysis method is used to measure the dynamic behaviour of the assembled structure. Meanwhile, the predicted data of the dynamic behaviour of the assembled structure is obtained by using finite element method. A few types of element connectors that available in finite element commercial software namely such as RBE, CBAR, CBEAM and CELAS have been investigated in order to represent the rivet joints in the assembled structure. In this study, the results obtained from the finite element analysis (in terms of natural frequencies and mode shapes) are then correlated with experimental counterpart in order to identify the level of the accuracy between element connectors that are used in modelling the rivet joints of the assembled structure. Finally, the reconciliation method using finite element model updating is used to minimise the discrepancies of the initial finite element model based on the most appropriate element connector to experimental data. The results reveal that CBEAM element connector has better capability and most appropriate comparing to other three element connectors to represent rivet joint in the assembled structure.
Experimental investigation of vibrations and noise characterization for spark ignition engine
Authors: Erdiwansyah  , Sani M.S.M. , Mamat R. , Zikri J.M. , Razak N.F.D , Munawir
Published: August 2019

An experimental study was carried out for measuring vibrations, noise and combustion characteristics associated correlations using a four-cylinder spark ignition engine. This study aims to investigate the effects of vibrations and noise on spark-polishing machines that are triggered by pure gasoline. This test runs at 15% engine load and 20% with engine speed 1000-2200 rpm at intervals of 300 rpm. The measurement of engine vibration in pistonic uses PCB Piezotronics ICP® Accelerometer (352C22). Overall tests that have been carried out for 20% loads at 1900 and 2200 maximum vibrations, the velocity is 0.214 and 0.234, compared to 0.617 and 0.562 for 15% loads. From the results of engine vibration analysis, it can be reported that increasing engine speed and the load is given engine vibration can significantly decrease. Generally, noise increases for all samples tested; however, reduced noise is recorded when speed and engine load increase. This observation is also consistent with other observations related to vibration and combustion noise, heat release rates, and ignition delays.
Experimental Modal Analysis Procedure for a Laser Spot Welded Hat-Plate Structure
Authors: Mohd Zin M.S , Abdul Rani M.N , Yunus M.A , Iskandar Mirza W.I.I Wan , Sani M.S.M
Published: August 2019

Measuring the dynamic behaviour of a structure made from light thin steel sheets becomes arduous as a result of the double impact, local modes and mass loading issues which lead to inaccurate results. In addition, the attachments of accelerometers, selection of suspension types and methods of excitation adopted to the measurement greatly affect the quality of the experimental results. The aim of this paper is to present detailed procedure for the experimental setup of a welded structure made from thin steel sheets. A hat shaped plate and flat plate connected together by several laser spot welds were used for the demonstration of the experimental modal analysis. The laser spot welded hat-plate structure was tested under free-free boundary conditions using impact testing with roving accelerometers and an LMS Test Lab. This work revealed that the proper procedures used for the experimental setup would help dynamicists enhance and improve the quality of the measured results of frequency response function and the results could be confidently used for the validation purposes and updating analytical models.
A Framework for Green Concrete Noise Barrier Materials using Palm Oil Clinker
Authors: Galip Noor Suhaida , Haron Zaiton , Mohamad Roslli Noor , Yahya Khairulzan , Jahya Zanariah , Azril Hezmi Muhammad
Published: August 2019

Noise pollution from traffic is an increasing environmental problem worldwide. The most popular mitigation measure is the control of path by means of construction of noise barriers. Current concrete barrier incorporated with perforated surface infilled with non-mineral fibre sound absorbing material on the highway side are the commonly found. The disadvantage of this type is it’s easily damaged and the non-mineral fibre is so dreadful to human health. On the other hand, palm oil clinker (POC) is a by-product waste material produced in palm oil mills, are currently dump in open land or landfill sites, which leads to environmental problems. POC is internally porous and if it replaces the aggregate in porous concrete it may absorb sound better than standard porous concrete which is the most important characteristic for noise barrier development. This paper discusses how the palm oil clinker substitution will make concrete noise barrier material to be labelled as green and sustainable. A framework for developing green noise barrier made of palm oil clinker concrete will also be presented and discussed.
Normal mode finite element analysis of aerofoil wing structure with different materials
Authors: Asri M N A M , Abdullah N A Z , Fouzi M S M , Sani M S M
Published: August 2019

There are a lot of study regarding on the aircraft components. One of the critical components for an aircraft would be the wings. The wing structure of an aircraft is one of the complex structures of a designed aircraft. This paper is about identifying the modal properties which are the mode shape and the corresponding natural frequencies of the aircraft wing structure. The modal properties of the wing structure would be compared for two different materials applied towards the wing structures which are the aluminium alloy AA-7075-T6 and AA-2024-T3 which currently being widely used by the aircrafts. The study for this aircraft wing structure would be using the approach of finite element analysis (FEA) method. The 3D model is design by using SolidWorks. The modal properties are identified with the help of MSC PATRAN and MSC NASTRAN. The results obtained for both materials for 10 mode shapes are compared and it could be observed that AA-7075-T6 are much lower compared to AA-2024-T3. Hence, from the result, AA-7075-T6 is more suitable to be used for the wing structures.
Tremor Quantification and its Measurements Using Shimmer
Authors: Musab Reem , As’arry Azizan , Rezali Khairil Anas Md. , Abdul Jalil Nawal Aswan , Raja Ahmad Raja Mohd Kamil , Md Zain Mohd Zarhamdy
Published: August 2019

This study aimed to provide a quantitative assessment of parkinsonian tremor through the precise measurement of tremor among Parkinson patients while taking into consideration specific parameters including acceleration, velocity, and displacement. The parameters were obtained by using transducers. For this assessment, three-axis accelerometer and three axis gyroscopic transducers embed in one device called shimmer. In this present paper, sensitivity assessment was used to measure the severity of hand tremors in two positions; resting and postural. Besides, the researchers obtained rotational movement along with tremors’ acceleration movements. The amplitude and frequency was taken from Parkinson patients’ hand. Shimmer sensor showed excellent correspondence of amplitude and frequency measurement with rotational transducer. The frequency of the patient’s hand tremor occurred between 1.594 Hz and 4.813 Hz. However, the accelerometer showed poorer correspondence compared to gyroscope measurement. At the end, gyroscope responses are more remarkable because of the low level of muscle activity required in the task for precise tremor measurements to appear in high sensitivity to this impairment tremor.
The Effects of Posture on Suspension Seat Transmissibility during Exposure to Vertical Whole-Body Vibration
Authors: Aisyah Adam S. , Abdul Jalil N. A. , Razali K. A.Md , Ng Y. G.
Published: August 2019

Suspension seat is used in the off-road condition to attenuate excessive vibration exposed to the human body. The efficiency of a seat reducing vibration not only depends on the dynamic characteristics of the seat, but the dynamic characteristics of human body and the characteristics of the input vibration as well. Tractor drivers adopted different postures during their farm work activities, which may influence the dynamic characteristics of the human body. However, the influenced of the driver’s posture on suspension seat transmissibility has received less systematic attention. Thus, this study is carried out with the objective to investigate the effect of different postures on seat transmissibility when seated on a suspension seat. Three male subjects were exposed to random vibration at 2.0 m/s2 r.m.s with frequency ranging from 1-20 Hz, while seated on a vibration simulator for 60 seconds. The subjects adopted four seating postures: (i) relaxed, (ii) slouched, (iii) tensed and (iv) with backrest support. The study found that relaxed and slouched postures have a resonance frequency at 2.0 Hz. However, as the posture changed to backrest support, the resonance frequency of the seat transmissibility slightly increased by 0.25 Hz. This study suggested that changing the postures caused changes in the dynamics of human body, and thus affected the suspension seat transmissibility. It is concluded that, non-linearity in suspension seat transmissibility is influenced by the changes of body postures.
Finite Element Model Updating of Dissimilar Plate with Rivet Joint
Authors: Rahman H. A. , Khairi N. D. A. , Sani M. S. M.
Published: August 2019

This study focusses on experimental modal analysis (EMA), finite element analysis (FEA) and model updating. The result of FEA and EMA will be validated and analysed. Then, the study extended to the early stage of model updating by assuming that the riveted dissimilar plates is a rigid body instead of two dissimilar plates. These modal parameters are crucial in providing various periods at which it will naturally resonate to avoid the structure continue to resonate and experience structural damage. Modal parameters of the dissimilar plate with rivet joint which include natural frequency and mode shapes were determined through EMA and FEA. Comparison of experimental data and the simulation data reveals a good correlation between the values of natural frequency. Minor discrepancies of the percentage of error between EMA and FEA are acceptable with the percentage of error is within the range of 0.4% to 13%. Furthermore, the conducted model updating able to reduce to an error range of 0.03% to 0.1%. Through this study, the best way of conducting finite element analysis and model updating for dissimilar plate material with rivet joint is also determined.
Quasi in-situ EBSD characterization of the evolution of microtexture and microstructure in non-oriented electrical steels during cold rolling and annealing
Authors: He Y. , Mehdi M. , Sanjari M. , Hilinski E. J. , Kestens L. A. I. , Edrisy A.
Published: August 2019

Non-oriented electrical steel sheets are extensively used to manufacture core laminations for electric motors. The microstructure and crystallographic texture of the final thin sheets have a significant effect on the magnetic quality of the lamination core. Controlling the development of microstructure and texture during thermomechanical processing of these steels is of great practical importance. Although the final microstructure and texture of the steel sheets are affected by all the processing procedures employed, cold rolling and final annealing have the most direct effect since these are usually the final steps to process the steel. Although much effort has been made to study the evolution of microstructure and texture in non-oriented electrical steels, the formation mechanisms of the final microstructure and texture during annealing (especially grain growth) are still not completely understood, which is partially due to the fact that it is very difficult to directly investigate these processes using conventional characterization techniques. In this research, a quasi in-situ electron backscatter diffraction (EBSD) technique was presented, which enabled the tracking of the changes of the morphology and orientation of individual grains during cold rolling and the subsequent annealing process. The experiments revealed the rotations of individual grains under plane strain compression, and tracked the formation of nuclei from the deformed matrix and the growth of new grains during the recrystallization process. The results provided valuable insights into the evolution of microstructure and microtexture during cold rolling and annealing of non-oriented electrical steels, and helped understand the mechanisms that govern the nucleation and grain growth during recrystallization.
Analysing mobility from austenite grain growth data
Authors: Kranendonk Winfried
Published: August 2019

To obtain information on mobility of grain boundaries in austenite grain growth data has been collected from the open literature, to fit a physics-based grain growth model, which relates the mean grain size to the annealing time. The suitability of this model for predicting the grain size as a function of time is discussed and some preliminary results on the reduced mobility are presented. For the compositions in the database it has been found that the activation energy ranges from 100 to 600 kJ/mol. Such high activation energies cannot be explained well with many solute drag models.
Microstructural and micro hardness variation during low temperature recovery annealing in C-Mn high strength Steels
Authors: Janakiram S , Gautam Jai , Phani P Sudharshan , Kestens Leo A I
Published: August 2019

Recovery was studied in four different grades of steel, ULC, HSLA and DP600 and DP800 with varying C-Mn content. All the steels samples were 80% cold rolled and annealed at 300 and 500°C for 30, 60,120, 300 minutes, mainly to study the hardness and microstructural changes. Specimens were further tested using micro Vickers hardness tester. Microstructural changes were observed using scanning electron microscope. The cold rolled microstructure consisted of ferrite in ULC and ferrite-pearlite in HSLA, DP600 and DP800 steels. All the grains were pancaked and aligned in the rolling direction. The Hardness values increases for annealed specimens at 300 and 500°C in HSLA, DP600 and DP800 compared to cold rolled condition, which can be attributed to hardening of the ferrite matrix due to pinning of dislocations by carbon atoms. The hardness values for annealed specimens in ULC and DP800 decreases at 300 and 500°C which is attributed to softening.
The effect of microalloying elements on prior austenite grain growth of low-carbon slab material
Authors: Hannula J , Kaijalainen A , Porter D , Kömi J
Published: August 2019

The effect of microalloying elements on the prior austenite grain growth of slab materials during slab reheating has been investigated. The investigated materials were laboratory castings with two levels of carbon (0.05 and 0.09 wt.%) and different combinations of microalloying elements, such as V, Nb, Mo and Ti. Experimental results were compared to equilibrium Thermo-Calc® simulations predicting the solubility of different precipitates during slab reheating. Based on slab reheating experiments at temperatures between 1100 – 1250 °C, Ti is the only alloying element to hinder prior austenite grain growth effectively above 1200 °C. For the steel containing high carbon with Nb, V and Ti microalloying, the average prior austenite grain size was less than 50 μm after the slab reheating to 1250 °C, which can be considered very small. According to Thermo-Calc® calculations, stable Ti(CN) precipitates are formed from the liquid and are in solution until 1500 °C. Until 50-60 % of soluble NbC -precipitates, austenite grain size remained relatively small in Nb-alloyed compositions without Ti, but after that grain size increased drastically. For only V-alloyed steels, already at the soaking temperature of 1100 °C hardly any VC precipitates exists based on Thermo-Calc® simulations, and after that grain coarsening can be assumed to be controlled only by the coarsening rate of austenite grains.
Recrystallization and grain growth at the interface of a bimetallic colaminated strip composed of two different Fe-Ni alloys
Authors: Poncelet J , Baudin T , Oliveira M de , Waeckerlé T , Ateba-Betanda Y , Brisset F , Helbert AL
Published: August 2019

Roll bonding is a solid-state welding process widely used to manufacture layered metal composites. Particular properties may thus be obtained using the physical features of each material of the composite. Bimetal plates consisting of two different Fe-Ni alloys were made by roll bonding followed by heat treatment for 90 minutes at various annealing temperatures. The effects of post-rolling heat treatments on the bonding strength of a bimetal strip were investigated in relation to the interface microstructure evolution. Both recrystallization and grain growth took place at the interface during annealing. In particular, nucleation of new grains as well as growing grains crossing the interface may have contributed to the improvement of the bonding strength. Moreover, diffusion through the interface was found to drastically enhance the bonding strength from 850°C up to 1050°C. However, excessive grain growth associated to porosity occurrence probably caused the saturation of the bonding strength beyond 1050°C.
Grain sizes and dislocation densities in fcc-metallic materials processed by warm to hot working
Authors: Torganchuk V , Morozova A , Tikhonova M , Kaibyshev R , Belyakov A
Published: August 2019

Our just received results on the deformation microstructures evolved in a medium-Mn austenitic steel during large strain warm to hot rolling were analyzed with a reference to other alloys with face centred cubic lattices and relatively low stacking fault energies. The structural changes were characterized by the development of dynamic recovery (DRV) and dynamic recrystallization (DRX). The deformation grain size decreased while the dislocation density increased with a decrease in deformation temperature. Both the grain size and the dislocation density could be expressed by power law functions of temperature-compensated strain rate, i.e., Zener-Hollomon parameter, with exponents of -0.33 and 0.2, respectively, in the case of discontinuous DRX. On the other hand, the exponents of -0.1 and 0.06 were obtained for the grain size and dislocation density dependencies on the temperature-compensated strain rate, respectively, under conditions of warm deformation accompanied by DRV and continuous DRX. Therefore, a power law function could be obtained between the grain size and the dislocation density with a grain size exponent of -0.6, irrespective of the mechanisms of microstructure evolution in a wide range of deformation conditions.
The operative dynamic recrystallization mechanism of austenite during the transient deformation in a Ni-30%Fe model alloy
Authors: Chen Wenxiong , Zheng Chengwu , Dianzhong Li
Published: August 2019

Effect of strain rate and its discontinuous changes on dynamic recrystallization (DRX) behaviours of a Ni-30%Fe austenitic model alloy were investigated by hot compression tests. The results show that, during deformation at slow strain rates, DRX occurs with discontinuous nature, i.e. the DRX nuclei preferentially appear along initial grain boundaries followed by a quick growth through the strain-induced boundary migration (SIBM). Interestingly, during the further deformation after an abrupt increase in the strain rate, it can be found that the subgrains which developed in the first stage of deformation would gradually transform into new DRX grains. Therefore, in spite of the low stacking fault energy austenite, the continuous DRX (CDRX) is indeed possible to be activated during the transient deformation. The strain-induced sub-boundaries developed in the first deformation stages are believed to transform into higher-angle boundaries easily in further straining after abrupt increase of the strain rate. By this way, the CDRX mechanism in austenite is significantly promoted. Moreover, the local growth of new grains also plays an important role in this dynamic softening process.
Continuous dynamic recrystallization during hot torsion of an aluminum alloy.
Authors: Poletti M C , Simonet-Fotso T , Halici D , Canelo-Yubero D , Montheillet F , Piot D , Kovács Z , Schell N , Tolnai D
Published: August 2019

Most commercial aluminum alloys are characterized by dynamic recrystallization at very large deformations in a continuous manner. The present study deals with the characterization and modeling of the evolution of the microstructure of an aluminum wrought alloy at large plastic deformations. Hot torsion tests of the AA6082 aluminum alloy are carried out using the thermomechanical simulator Gleeble®3800 in a wide range of temperatures and strain rates. The use of water quenching immediately after deformation avoids any static restoration during cooling. Microstructural investigations are carried out by means of electron back scattered diffraction using a scanning electron microscope to determine the grain and subgrain structures, as well as the misorientation distributions. In-situ synchrotron radiation tests during hot torsion are used to confirm the continuous dynamic recrystallization (CDRX) by the evidence of the conversion of low angle boundaries (LAGBs) into high-angle boundaries (HAGBs) and the formation of new texture. Experimental investigations show that CDRX starts with the formation of LAGBs at low strains (center of the sample). By subsequent straining (close to the surface of the sample), the accumulation of dislocations at the LAGBs causes an increase in their misorientation until a critical value is reached and LAGBs transforms into HAGBs. The developed model consists of a microstructural model, equation rates and constitutive equations. The microstructure is described by three internal variables. Their rates are evaluated using the Kocks-Mecking model. The modelled and experimental flow stresses show softening due to the consumption of dislocations and the continuous formation of new HAGBs.
Utilization of rice fields for brick industries and farmers environmental awareness
Authors: Anwar R K , Rusmana A , Rizal E , Khadijah U L S
Published: August 2019

This paper discusses how farmers in Garut regency, West Java, convey the maintenance of environment awareness. This is important for the community because their activities in the brick industry have a very close relationship with the conversion of agricultural land. It was indicated by the fact that besides profit, there is also a loss. The existence of the brick industry will lead to the emergence of social problems and environmental problems. This study uses multiple case review methods. The cases consist of brick industry centers in Garut Regency. This study examines how peasants understand about soil maintenance. Interviews and observations are used to collect data. A face-to-face interview with the questionnaire was also developed for this study. The findings of the survey indicate that farmers’ societies do not think much about the consequences of their land-based economy. Nevertheless, there are efforts to cultivate the awareness of the farmers both from the government and non-government that can be communicated well to the community because it uses various media both traditional, modern and digital.
Patterns of variation magnetic properties and chemical elements of soil profile in landslide area of South East Sulawesi Indonesia
Authors: Eso Rosliana , Safiuddin La Ode , Bijaksana Satria , Ngkoimani La Ode , Agustine Eleonora , Tamuntuan Gerald , Tufaila M. , Syaf Hasbulah , Harudu La , Alfat Sayahdin , Usman Ida , Hasrorayan  , Ardin
Published: August 2019

Applications of the magnetic properties of rock continue to be developed because of its ability to integrate the understanding of the variation patterns of minerals and chemical elements in the process of soil formation and also their influence due to external factors . The primary objective of this study is to knowlege how the trends of variations of the magnetic properties and chemical elements on soil profile in landslide area, and how the association between the element as welpalal as the association between chemical elements and magnetic properties. Eleven soil profiles are the focus for the study of magnetic properties (parameter of magnetic susceptibility) and their elemental content (i.e., using the X-Ray Fluorescence, XRF). From the soil profiles studied, one hundred and twenty-four samples were taken and analyzed for their magnetic properties and elemental content. The results of this finding show that the trend of variation in magnetic susceptibility and chemical elements in soils differs from the normal soils and soils affected by human activity. The linear correlation between χLF and χFD values indicates that the soil profile in this study is a natural soil profile even though it has undergone changes due to landslides.
Utilization of activated carbon from coconut shell in remediating heavy metal waste in soil around mining area
Authors: Septiana L A E S , Hidayah A N , Laurencia A , Agustine E
Published: August 2019

Soil contamination by liquid waste that containing heavy metals in Jendi Village, Selogiri Sub-District, Wonogiri Regency has occurred for a long time. This situation is affected by the Traditional Gold Mining activity in that region. To overcome this problem, the authors utilize activated carbon from coconut shell as an easy, effective and environmentally friendly remediation method. In this research, activated carbon is believed can adsorb heavy metal waste around the gold mine area. This research was conducted from August 9, 2017 - December 28, 2017 by taking samples of waste in the gold mine area and applying 200 ml of the waste to a soil miniature. Parameters observed were Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The results show that the existence of heavy metal in soil is decreasing. So, the activated coconut shell carbon effectively in remediating soil that contaminated heavy metal waste.
Assessment of agricultural drought in paddy field area using Vegetation Condition Index (VCI) in Sukaresmi District, Cianjur Regency
Authors: Yulistya V D , Wibowo A , Kusratmoko E
Published: August 2019

Drought is a phenomenon which happens in spatial and temporal scale. One of the sectors affected is agriculture. In August 2015, a severe drought happened in Sukaresmi Village of Sukaresmi District causing harvest failures. This study aims to analyze the distribution of agricultural drought level of severeness in Sukaresmi District during August 2013 until August 2017 from spatial and temporal aspect by using VCI (Vegetation Condition Index) method and finding the correlation between the drought extent and rainfall data as the expected cause. The monitoring of agricultural drought in this study was carried out by utilizing remote sensing derived VCI by Kogan (1995). This index obtained after the NDVI value of Landsat 8 imageries in the given period normalized for each pixel. VCI shows how close the vegetation condition compared to its best and worst condition within the period. The result shows an agricultural drought in Sukaresmi District occurred throughout the years. 2015 was the year with the greatest average extent of agricultural drought. There is also a negative and weak (r = -0.212) correlation between the extent of drought and rainfall variable which means the climate did not mainly cause the phenomenon.
Mapping vulnerability level of tsunami disaster in Coastal Villages of Pariaman City, West Sumatera
Authors: Hadi Fakhri , Damayanti Astrid
Published: August 2019

Pariaman city is one of the cities that is indicated prone to tsunami disasters because it is close to the shoreline and directly adjacent to the Indian Ocean. Coastal village of Pariaman City that faces directly to the offshore makes the coastal villages more vulnerable to tsunamis. Settlement is a residential area that must be protected, so mapping the vulnerability’s region to the tsunami that is focused on the settlements is needed to protect the residents. This study aims to map vulnerability level of settlements to tsunami disaster in the coastal village of Pariaman City. Vulnerability region is seen from exposure, sensitivity, and resilience. The data in this study are elevation, distance from shoreline, slope, distance from river, population, quality of the building, knowledge of disaster mitigation, and socialization of disaster mitigation. Each component is then overlaid with overlay techniques (scoring and weighting) of Geographic Information System (GIS) to obtain the vulnerability. The results showed that settlements in the coastal villages of Pariaman are dominated by “Low” vulnerability, followed by “Moderate” and “High” vulnerability. The “High” vulnerability levels are in low elevation, close to shorelines, low slopes, close to river, low building’s quality, high population, and no socialization.
Characteristic aquifer in volcanic terrains: case study at Caldera Lake Maninjau, West Sumatera - Indonesia
Authors: Sehabbudin Muhammad , Dianto Aan , Subehi Luki , Singgih Irianto TH
Published: August 2019

Lake Maninjau is a caldera lake with volcano-tectonic type. Lake Maninjau composed of andesit and tuff formation. The existence of water was sourced by rain and ground water. The aquifer units consist of local productive aquifers and rare ground water aquifer. The purpose of this research is to know the characteristic of aquifer in volcanic terrains support water stability in lake. Geoelectric measurements with Wenner configuration were obtained to know subsurface resistivity which a device used were IRES T300f, used RES2DINV software. The results showed that characteristic of aquifer divided into two areas, rare aquifer and productive aquifer. Productive aquifer with average 21.2 – 213 ohm meter, located at Tanjung Sani (elevation 462 m) had similar with Batang River (elevation 701 m). Rare aquifer with average value 48.4 – 436 ohm meter located at Hamka School (elevation 632 m) and Lawang Park with (elevation 1,294 m). The results of geoelectric reconstruction revealed that volcanic terrains around Lake Maninjau were dominated by rare groundwater aquifer, where capable to keep groundwater in small volume. Further, Fault with northwest – southeast as the general direction were considered to drain water through volcanic terrains.
Characteristics of magnetic susceptibility and geochemistry of paddy soils in Malang City, East Java
Authors: Daryanti N Y , Zulaikah S , Mufti N , Haryati D S
Published: August 2019

Paddy soils are a typical anthropogenic soil resource that has a wet-dry cycle and plays an important role almost all over the world, mainly in Indonesia. Along with the development of the current area of rice farming, the changes of many environmental from natural areas has undergone to settlements area and influenced by human activities. This study examines the magnetic properties and element content in special soils of paddy farming areas in the city of Malang. In this study magnetic susceptibility measurement was conducted on 60 samples taken from 3 locations, using Bartington susceptibilitymeter MS2B. The element determination was conducting by XRF (X-Ray fluorescence) on 3 representative samples. The result showed that the average of magnetic susceptibility low frequency (χlf) of paddy soils was 3.66 ×10−6 m3kg−1. The chemical elements in paddy soils are dominated by Fe, that is around 41.2 % then followed by Si about 36.7%, Al about 12%, Ca about 10.5% and Ti is the lowest value, that is about 2.13%.
Magnetic characterization of soil to determine the source origin. Case study: soil around Bromo Volcano, Tengger Volcanic Complex
Authors: Santoso N A , Syaifullah K I , Zulaikah S , Bijaksana S
Published: August 2019

The research on soil characteristics is very important in Indonesia. Indonesia is a well-known country for its volcanoes in the world. Many lush areas around the volcano are still active. One of the famous and still active volcanic complexes is the Tengger Volcanic Complex. The aim of this research is to analyze the magnetic characteristic of four volcanic soils around Bromo Volcano. The sample consists of soil from Gubug Glakah (GGK), Ngadirejo (NDJ), Nongko Jajar (NKJ), and Waringinanom (WAN) Village. Rock magnetism method combine with geochemical analysis are applied in this study. The results of this research are a significant difference in magnetic susceptibility value of WAN soil (1976.4 × 10−8 m3/kg) with magnetic susceptibility value of three other soils (between 900-1200 × 10−8 m3 / kg). Meanwhile, X-Ray Fluorescence (XRF) analysis showed that FeO concentration on WAN soil was lower than other soils. This indicates that the concentration of magnetite minerals (Fe3O4) on WAN soil is higher than other soils. The difference of magnetite mineral concentrations in the soil may be due to difference sources. Based on these results, it is concluded that WAN soil may not come from a similar source. This study still needs further research.
The government policy on the conservation of natural resources and ecosystems in Kuningan, Indonesia
Authors: Akhmaddhian S , Hartiwiningsih H , Handayani I GAKR , Yuhandra E , Yuhandra  , Budiman E,H , Rahmat D , Syafrudin O
Published: August 2019

The utilization of natural resources should consider the availability and the carrying capacity of the nature for the society’s prosperity purpose since the excessive use of natural resources can lead to any disasters. The purpose of this study is to find out and analyze the implementation of conservation policy of natural resources and ecosystems in Kuningan. The method used was mixed method and the data collection techniques were interview, observation, and literature study. The results revealed that the conservation policy of natural resources is regulated based on Law Number 5 of 1990 about The Conservation of Natural Resources and Ecosystems, and other related Regulations such as Government Regulation, Ministerial Regulation, and Regional Regulation. Further, regarding the implementation of conservation policy of natural resources and ecosystems in Kuningan, the regional government stipulated the protected forest area of Mount Ciremai to become The Mount Ciremai National Park in 2004 and created regional regulations concerning the conservation of water resources, botanical gardens, and bird’s protection. In conclusion, the implementation of conservation policy of natural resources and ecosystems in Kuningan is running well. Yet, the government’s consistency in conducting programs related to the conservation of natural resources and ecosystems becomes the future challenge.
Study on linearized inversion of surface wave dispersion for estimating near-surface shear wave velocity
Authors: Lesmana Aditya , Priyono Awali , Yudistira Tedi , Agustina Anisa
Published: August 2019

Near-surface shear wave velocity is very important for geophysical and geotechnical engineering. The use of surface wave for characterization of the near-surface subsurface involves three steps: acquisition, extracting dispersion curve, and inversion method to generate near-surface shear wave velocity. In this study, we explored a linear inversion technique to see the effect of some parameters such as the initial model and the damping factor on the inversion results. We used the Levenberg-Marquardt algorithm and written in Matlab. Synthetic data used three-layer earth model with assumed homogeneous, isotropic, flat, and half-space. Synthetic examples demonstrated that inverted result depends on the initial model. Based on our results, we have ranged from 30% to 120% of the true model in providing the initial model. It is found that there is an asymmetry between the range of the initial model which is larger and smaller than the true model. This is due to the non-linearity of the differential equation and the solution of the Jacobian matrix using numerical approach. There are several suggestions for solving this problem: (1) using an analytical approach, (2) higher order deductions when using numerical approaches. In term damping factor, our result show range between 10−2to 1 give a stable inversion.
The fault identification by gravity and seismology in West Lembang Segment
Authors: Laesanpura Agus , Afnimar  , Dahrin Darharta , Abdurachman Dadi
Published: August 2019

The Lembang fault considering vulnerable because of the site is near downtown Bandung. The west Lembang segment is the rural area of Cibodas. The two opinions is emerging, become normal fault or strike slip fault, based on recent earthquake (2010 onward). The geology data show the structure is observed by the outstanding topographic extended about 20 km, with volcanic rock very dominant. The seismology data is analysed for year 2011 in Mw less than 3, and classical fault plane solution is obtained. The gravity data is better acquired than 0.1 mGal, with elevation precision better than 60 cm. The upward Continuation, and second vertical derivative, is applied on data, as well as modelling 2.5D. The section is presenting in one section only, while data is getting in larger area. The seismology data show mostly for event is strike slip although in several parts having event normal. The gravity data is not ideal as graben like structure but rather locally low about 10 mGal amplitude. The combining the two methods suggested the slip zone or sag pond is more possible for the local anomaly. Besides, the Lembang fault is extended toward north rather to west or south.
Delineation of sedimentary sub-basin and basement configuration based on the upward continuation filter and 2d and 3d modeling of gravity data (a case study: Rembang Area and its surroundings)
Authors: Muharina Gita Nia , Setiadi Imam , Santoso Budi , Supriyana Eddy
Published: August 2019

East Java Basin is classified as a classical back-arc basin so that it is indicated that the basin has a complex structure and stratigraphy where there is an area called Rembang High. Rembang High is a gravity anomaly term that appears in Northern of East Java Basin area which has a higher value than other physiographic zone and is assumed to be associated with Rembang anticline. It is interesting to study the basement configuration and sedimentary sub-basin presumption. The gravity anomaly is supperposition of all anomaly sources in the subsurface, namely regional and residual anomaly. The separation of regional and residual anomaly is done by using upward continuation filter. Optimum continuity height can be obtained from the cross correlation of two continuity heights. The tesidual anomaly was obtained from the difference between Bouguer and regional anomaly. In addition to use the optimum continuity height, anomalous source depth estimation is obtained by using spectral analysis. The results obtained using both upward continuation and spectral analysis shows the same optimal depth value of 3500 meters or 3.5 kilometers. 2D and 3D modeling is done to facilitate the interpretation of the condition of geological structures below the surface. The modeling result shows the existence of rocks that are raised (basement high) at a depth of 3.5 kilometers and basin depocenter at a depth of 5 kilometers with a basement which is assumed as a metasediment rock has > 2.7 g/cm3 density.
Review of time-lapse microgravity correction due to shallow groundwater variation
Authors: Pasengo Y I , Widodo L E
Published: August 2019

Microgravity surveys can be applied for reservoir monitoring, such as monitoring of hydrocarbon or geothermal reservoirs. One factor that needs to be corrected from gravity data in reservoir monitoring is the gravity signal due to shallow groundwater variation. The correction due to shallow groundwater effect shall be calculated from groundwater change, in this case can be measured from groundwater table change. So far, correction due to shallow groundwater variation in microgravity data is calculated against the influence of groundwater mass change in the saturated zone only, while the change of mass of groundwater in the unsaturated zone is ignored, thus giving an over-estimated correction result. The purpose of this paper is to review time-lapse microgravity correction due to shallow groundwater variation by including the influence of groundwater mass variation in the unsaturated zone. This review includes a case study using three-point piezometer groundwater data. The correction due to groundwater mass variation in the unsaturated zone is obtained by calculating the difference between the total water content at two measurements over a certain time interval. The calculation of total moisture content in the unsaturated zone is based on a soil-water retention curve that describes the relationship between moisture content and pore pressure. Considering the effect of water mass in the unsaturated zone, the total correction due to shallow groundwater variation has a smaller range, about 35% to 50% compared to the correction that only considers the effect of water mass in the saturated zone alone.
Fuzzy logic application for cave entrance identification
Authors: Pambudi Ridwan Arif , Damayanti Astrid , Marko Kuswantoro
Published: August 2019

Fuzzy logic allows ambiguity and obscurity. Fuzzy logic explains that truth is not an absolute way. Rather, it presents data in ranges. This becomes the advantage of fuzzy logic in categorizing spatial data in a natural way. Cave entrance identification in karst landscape has an important value because caves are the alternative water resources and conservation region for biota biodiversities, archaeological heritage, and other research for the different discipline of science. This research was conducted in Gunung Sewu Karst Landscape with varied physiography, Ponjong and Semanu District, Gunungkidul Regency. The purpose of this research is to examine the accuracy of fuzzy logic in identifying cave entrance. This research is an integration between geographic information system and remote sensing. Alos Palsar imagery is processed to produce drainage density, slope, and elevation region, while Sentinel 1 imagery processing produces lineament density. Other spatial data used in this research include monthly rainfall data and geology formation. All variables in raster format are reclassified using fuzzy membership and then overlaid with fuzzy overlay. The result is that cave entrance is found in the region with high fuzzy logic value range. Fuzzy logic has high accuracy in identifying cave entrance in Ponjong and Semanu District, Gunungkidul Regency.
The impact of season change to salt productivity in Pangenan Sub-district Cirebon Regency in 2013 and 2014
Authors: Halil Amrih
Published: August 2019

Salt as a commodity will always be needed by human as well as human need for food. Climatic conditions, less favorable weather changes are a natural factor that inhibits salt production. This study was conducted to analyze changes in salt productivity and salt farmer income due to seasonal changes in Pangenan Sub-district, Cirebon Regency as the largest salt producer in West Java. The variables of the research are seasonal conditions, salt production, salt pond area, salt productivity, selling price and salt farmer income, in 2013 and 2014. Variable data obtained from Fisheries and Maritime Office of Cirebon Regency, and the results of direct interviews with salt farmers then seen relation through statistical calculations using the Pearson Product Moment Correlation method. The result of the calculation shows the correlation value between the change of season and the productivity of 0.368 as r counting, r table of 0.320, and the significance of 0.023, and the value of income correlation with the number of dry months of 0.316 as r counting, r table of 0.271 and significance of 0.027 with significant correlation at 0.05 or 5%. The results show that r counting > r table and significance < significant correlation which shows the influence of seasonal changes seen from the number of dry months to productivity and income, where more and more dry months in one year, the greater productivity and income of salt farmers.
Geochemical distribution and behaviour of mercury and arsenic in the Brunei-Muara District, Brunei Darussalam
Authors: Pg Dr Karim Khairunnisa Nazirah , Norazme Nur’Aqidah , Seow Cheng Cynthia Shie , Zulkefle Nurul-Izzyani , Tsikouras Basilios
Published: August 2019

Both mercury and arsenic are toxic elements which can affect human health and ecosystems negatively. Monoelemental geochemical maps were constructed to identify the spatial distribution of both mercury and arsenic in Brunei Muara District of Brunei Darussalam. This paper is a product of a pilot project aiming at constructing the geochemical atlas of Brunei Darussalam. Extensive field work and sampling enabled us to collect 187 subsoil samples with a sampling density of 1 km2. Both mercury and arsenic were analyzed in the fine fraction and the relevant geochemical maps were constructed and correlated with the geological, land use and different vegetation types maps of Brunei Darussalam. Certain anomalies observed on heat maps can be linked to anthropogenic activities in industrial and urbanised areas, as well as to analyze mobility of these elements due to natural phenomena and different types of soils.