bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlation of numerical and experimental analysis for dynamic behaviour of a 3 blade propeller structure
Authors: Brapakaran P , Abdullah N A Z , Fouzi M S M , Sani M S M
Published: August 2019

In pursuance of deciding the dependability of data gathered by testing a finite element modal in the software version, experimental data is frequently used for validation. On account of finite element analysis, it can sometimes be considered as inaccurate particularly when applied to the complex structure, for example, a propeller blade. This is because of challenges that may happen in the modelling of joints, boundary conditions, and damping of the structure. In this research, a procedure of correlation and validation of the model-based test plan with modal testing results was conducted. Modal properties (normal frequencies, mode shapes, and damping ratio) of a propeller blade structure were resolved by using both test experimental modal analysis (EMA) and finite element analysis (FEA). Correlation of both sets of data was performed for validation. It created the impression that there was a noticeable estimation of error between those two sets of data. Small discrepancies of percentage error of obtained natural frequency for FEA and EMA makes both of the methods can be applied to determine the dynamic characteristic of the propeller structure.
Development of Vibration Test System to Measure Human Biodynamic Responses to Hand-Transmitted Vibration (HTV)
Authors: Aizuddin A M , Jalil N A Abdul , Rezali K A Md , Ng Y G
Published: August 2019

Workers commonly experience hand-transmitted vibrations (HTV) especially in industries involving power tools. Vibration exposure will differ by individuals where prolonged and unmonitored exposure can lead to the development of symptoms known as hand arm vibration syndrome (HAVS). A deep understanding of human response to HTV is required to provide feasible solutions to lessen its adverse effects. Research has been extensively conducted on exploring the vibration transmission to the hand-arm system. However, there is limited study on the effects of handles mounted on a damping material or suspension systems. The objective of this study is to develop a vibration test system to measure the human biodynamic response to hand-transmitted vibration. Engineering design theory were used to formulate the essential design requirements of the system. The evaluation and selection of concepts were done. The design was modelled, and frequency analysis was performed using Computer-Aided Engineering (CAE) software. The frequency analysis results showed the first 10 modes in the frequency range of 1320 – 5088 Hz and therefore will not have resonance issues in the 25 – 1250 Hz frequency excitation range as per requirement. The prototype design was shown to comply with the product design specification and final detail design drawings were approved for fabrication. In conclusion, an instrumented handle with a modular expansion slot had been appropriately designed to measure human biodynamic responses due to hand-transmitted vibration.
Review on the Vibration Perception Threshold to Early Detect Diabetes Mellitus
Authors: Taufiq Zaliran M. , Md Rezali Khairil Anas , Guan Ng Yee , As’arry Azizan , Abdul Jalil Nawal Aswan
Published: August 2019

The total population of diabetic patients increases from 4.7 % to 8.5 % in the adult population worldwide in only three decades. In Malaysia, more than 3 million of total population have been inflicted with diabetes. Vibration Perception Threshold is a non-invasive technique that can measure loss of sensation due to diabetic peripheral neuropathy. The threshold mainly depends on the frequency of vibration, the area of contact, the applied force, and the location of measurement. This paper will review on the factors influencing the vibration perception threshold and recent studies on the use of VPT to detect diabetes.
Secondary recrystallization induced by composite precipitates in magnetostrictive Fe-Ga alloy thin sheet
Authors: He Zhenghua , Sha Yuhui , Gao Yongkuang , Chang Songtao , Lei Fan , Fu Quan , Zhang Fang , Zuo Liang
Published: August 2019

Secondary recrystallization of Goss ({110} < 001>) texture is successfully produced by using nanometer-sized composite inhibitor in primary cold rolled Fe81Ga19 alloy sheet. Nanometer-sized sulfides consisting of MnS and Cu2S are dispersedly precipitated during hot rolling and normalization as inhibitors for secondary recrystallization. Strong γ texture with peak at {111} < 112> and weak Goss texture distributed through the sheet thickness in primarily annealed sheets can provide favorable environment for the secondary recrystallization. The higher onset and finishing temperatures of secondary recrystallization confirm the stronger inhibition and driving force originated from the composite inhibitors. Centimeter-sized Goss grains and large magnetostriction coefficient are obtained by primary cold rolling methods without surface energy effect. The result indicates that complete secondary recrystallization in Fe-Ga alloy can be realized by precisely controlling inhibitor characteristic and primary recrystallization texture.
Effect of hot band annealing on texture and grain size distribution of primary recrystallization in grain-oriented silicon steel
Authors: Ko K J , Park J T
Published: August 2019

During final high-temperature annealing in grain-oriented silicon steel, a few Goss grains grow exclusively fast and consume the matrix grains, which are related to the quality of the final product. The optimization of texture and microstructure in primary recrystallization is crucial to achieve the sharp Goss texture in grain-oriented silicon steel. The driving force for this phenomenon is the reduction of grain boundary area, which can be decribed as a reduction in grain boundary energy. The distribution of grain boundary and its energy determined by texture and microstructure of primary recrystallization are very important data to understand the optimization point. The hot band annealing is known to be a prerequisite for the high quality product in grain-oriented silicon steel. It can affect the evolution of microstructure and texture in primary recrystallization. In this study, the influence of the hot band annealing temperature on the texture and grain size distribution in primary recrystallization was investigated in detail.
Influence of grain size before cold rolling on development of crystallographically equivalent main texture component in recrystallization texture of 3% Si-Fe
Authors: Imamura T , Hayakawa Y
Published: August 2019

3%Si-Fe sheet produced by high cold rolling reduction over 80% has strong {111}<112> recrystallization texture. This orientation has two crystallographically equivalent orientations such as (111)[1 -2 1] and (111)[-1 -1 2]. However, there are a few previous works in which these orientations are investigated separately. In the present study, the recrystallization behavior of the crystallographically equivalent orientations of {111}<112> was investigated using two samples with different grain sizes before cold rolling. Both recrystallized samples had strong {111}<112> component texture. The sample with a small grain size before cold rolling had almost the same fraction of each equivalent orientations, while the sample with a large grain size had substantially different fractions of each equivalent orientations. Spatial distribution of two crystallographically equivalent orientations in the sample with a small grain size before cold rolling was almost homogeneous, however that in the sample with a large grain size before cold rolling was inhomogeneous. It is considered that these differences are explained by the assumption that a certain large grain before cold rolling will generate only single crystallographically equivalent orientation after cold rolling and annealing.
Basal texture formation behavior of M1 magnesium alloy during high-temperature compression deformation
Authors: Park M , Kim K
Published: August 2019

Understanding the formation behavior of basal texture is important for improving formability. Many researchers found that deformation condition was an important factor in order to texture control on AZ system magnesium alloy. In case of M1 magnesium alloy has been investigated in texture formation resulting from grain size manipulation by precipitation, but there seems no studies on the texture development during high temperature on M1 magnesium alloy by deformation condition. In this study, microstructure evolution and texture formation behavior is investigated under various deformation conditions in M1 magnesium alloy. In order to make the same initial conditions, M1 magnesium ingot was rolled at 673K with a rolling reduction of 30%. Uniaxial compression test specimens were machined in such a way that the compression plane was parallel to the rolling plane, and subsequently annealed at 823 K for 1h. Uniaxial compression tests were carried out at 673K and 723K under a strain rate of 5.0x10−2s−1up to a strain of -1.0. EBSD measurement was performed for observation of crystal orientation distribution. As a result, occurrence of the dynamic recrystallization was confirmed. The position of maximum axis density of the texture and its intensity were varied depending on deformation conditions.
Microstructure and texture of a severely warm-rolled and annealed AlCoCrFeNi2.1 eutectic high entropy alloy
Authors: Reddy S R , Sunkari U , Lozinko A , Guo S , Bhattacharjee P P
Published: August 2019

The effect of warm-rolling and subsequent annealing on the evolution of microstructure and texture was systematically investigated in a lamellar (L12+B2) AlCoCrFeNi2.1 eutectic high entropy alloy (EHEA). The EHEA was warm-rolled at 400°C up to 90% reduction in thickness and annealed at different temperatures. Ultra-fine lamellar microstructure evolved after heavy deformation with the characteristic textures of the two phases. Annealing treatments resulted in the gradual development of an ultrafine micro-duplex structure with increasing annealing temperature, even though the alloy showed significant resistance to grain growth. The annealing process was featured by concomitant microstructural and textural changes.
The evaluation of irrigation water requirement under climate change phenomenon in the urban area (a literature study)
Authors: Rozita E , Sutjiningsih D
Published: August 2019

Irrigation is important for agricultural activities because it distributes water into irrigation area and provides water for crop growth. The appropriate and effective water allocation supports agricultural productivity. Generally, irrigation activities get water from rainfall and it is very depending on several climate variables for example temperature, humidity, duration of radiation and wind velocity. Several climatic variables are important for agriculture since they affect the evapotranspiration rate that it will determine irrigation water requirement rate. Therefore, irrigation water requirement is sensitive if climate change happened. In the other hand, decreasing of agriculture area as the agricultural land conversion gradually will reduce the irrigation service area particularly in the fast-growth area in development. So that, irrigation water requirement also will be reduced. Irrigation water requirement should be evaluated simultaneously in order that it can be allocated appropriately. This paper was written to develop an evaluation method for irrigation water requirement through analysis of climate change trend, agricultural land conversion and irrigation efficiency based on the literature review. The reviews result selected method i.e. Mann Kendall Test for climate change trend analysis, spatial analysis for agricultural land conversion and comparison of inflow and outflow for irrigation efficiency analysis.
Spatial pattern of drought disaster area and types of agriculture plant in Lebak Regency, Banten Province
Authors: Susilowati M H D , Wibowo A , Susiloningtyas D
Published: August 2019

Drought is a natural phenomenon that is one of the most frequent natural disasters in Indonesia. Significantly reduced water availability characterizes drought over a period occurring over a large area. Thus, drought occurs due to the deviation of weather conditions, that is lower rainfall than normal conditions that occur in a region. Lebak Regency is a dry area that has average monthly or annual rainfall below normal and most agricultural activities on dry land. The research objective is to analyze the drought and plant species in Lebak Regency, Banten Province. The method of analysis used in this study is spatial analysis (spatial analysis) and statistical analysis (Chi-Square). The results found, e.g. (1) The high drought areas concentrated in the northeast and southwest regions that are far from the center of Lebak Regency. (2) The types of crops are dominated by plantations, especially outside the Capital Region of the Regency. (3) The relationship between drought and crop type is insignificant at the real level of 0.05, which means that in high drought areas it is not always planted with certain types of crops. This research concluded that drought in Lebak Regency concentrated in the northern and southern part outside the capital city and the agriculture type dominated with the plantation.
Risk level of landslide disaster in Wonosobo
Authors: Saraswati Ratna , Harist M Chaidir , Putri Dian Nurhandayani , Afif Humam A , Wibowo Adi , Ash-Shidiq Iqbal Putu
Published: August 2019

Entering the rainy season can certainly cause various disasters, such as landslides. National Agency for Disaster Management (BNPB) noted since early 2017 to December 4, 2017 recorded as many as 577 incidents of landslides throughout Indonesia. Wonosobo is of the regency in Central Java that has occurred of Landslide. Based on Indonesia Disaster Information Data (DIBI) within 2017 until now in Wonosobo regency there are 9 landslide. By SMORPH modelling, found that the area of landslide potential with the highest grade in Wonosobo district of 17% area, and for sub-district and the sub-district with the highest potential landslide is Wadaslintang with the percentage of 13.85% area. Therefore, it is necessary to conduct research on risk level of landslide to reduce fatalities and material loss. To know how risk level, indicator used is landside potential area, vulnerability, and capacity. The output is risk level area of landside in Wonosobo, and for final results indicate that areas experiencing low risk levels are 7688,144 km2 or 8%, moderate 10111,89 km2 or 11%, and high 78123,15 km2 or 81%. Landslide risk distribution with high class are dominates in north, south, and west.
Assessment of loss due to flood hazard in Singkawang City (case study: flood in 2016 at Singkawang City)
Authors: Taris H , Tambunan M P , Marko K
Published: August 2019

Singkawang City is in the Province of West Kalimantan, which is located above an alluvial plain, that causing the city to be prone of flood. The last flood that occurred happened in 2016, which resulted in many flooded buildings and hundreds evacuated resident. This research purposes are to identify the hazard level of flooding and then proceed with the assessment of economic losses. The flood hazard levels are obtained by overlaying the flood characteristics parameters, i.e. frequency, duration, and height of the flood. The method for assessing the rate of the damage is done by purposive random sampling method with consider to the flood hazard level and building value. The result showed that from 84,96 ha of flooded areas, flood hazard level is dominated by low and medium hazard, with percentage of area 44,02% and 43,03%, and high classification with percentage of 12,95%. The loss assessment for this research shows that the total loss from the flood is Rp15.838.232.500 (1.150 million USD). There is a difference in distribution amount of losses, which is strongly affected by the category of building value and the level of flood hazard from the existence of the building.
Landslide susceptibility mapping using sinmap method in a small hilly area: case study in Cibanteng Village, West Java
Authors: Affandani A Y , Kusratmoko E
Published: August 2019

This paper presents the results of landslide susceptibility mapping in small hilly areas, Cibanteng village, Cianjur district, West Java. In this study. the physically-based model SINMAP (Stability Index Mapping) was applied in the GIS platform. The SINMAP model simulation requires data of physical properties of soil, such as cohesion value, internal friction angle, and soil hydrology to calculate the value of factor of safety (FS). The values of cohesion and fraction angel for the 10 sample points were obtained from the laboratory test results, while the value of soil hydrology, i.e hydraulic conductivity, transmissivity, effective rainfall and index wetness, referred to the literature source. The DEM (digital elevation model) was generated from the 1:25,000 digital topographic map, which produced the soil slopes and specific upstream contributing areas. The result of SINMAP model simulation shown that the regions with a high landslide susceptibility (FS <1, unstable) were spread unevenly with an area of 261ha (17,6% of the study area). The Landslide susceptibility map from the SINMAP model provided a satisfactory result with an accuracy of 62,5% against to the landslide events occurred during the period 2010-2017.
Detection of drought area using greening index and wetness index in Sukaresmi Subdistrict, Regency Cianjur, West Java
Authors: Anugerah M M , Wibowo A , Kusratmoko E
Published: August 2019

Drought is a natural disaster that reduces the supply of water in the atmosphere or on the ground, causing plants cannot grow normally. Drought is causing the decrease of plantation and harvest area, productivity, and quality of agricultural products. Sukaresmi Subdistrict, Cianjur Regency is depending on agricultural sector and has the risk of loss from drought. This research aims to detect spatial and temporal of drought areas and to analyze drought areas according to the physical condition of the land (altitude, slope, soil type, and land use) in Sukaresmi Subdistrict. This research uses Landsat 8 OLI imagery data from July-September 2013 and June-August 2017 analyzed by Normalization of Differences Vegetation Index (NDVI) and Tasseled Cap Transformation (TCT). Overlay of the moderate, high, and very high drought classes in the same year will generate drought areas that overlap each year. Drought areas during 2013 and 2017 are 726 hectares or 8% of the total Sukaresmi Subdistrict area, dominates the Kawang Luwuk Village and Cibadak Village in the western part of Sukaresmi Subdistrict. Mostly, drought areas located in paddy field land use (322.18 hectares); brown latosol soil type (447.85 hectares); and altitude of 500-1000 msl (624.1 hectares).
Complexity analysis of interconnected pore using hydraulic tortuosity
Authors: Juliust Hessel , Amien M. Nashih , Pantouw Genki Tanod , Eljabbar Latief Fourier Dzar
Published: August 2019

The complexity of the pore structure has been analysed using hydraulic tortuosity. The hydraulic tortuosity is defined as the ratio between the total curvature angles of the fluid flowpath to the distance between two facing sides of the sample. The fluid flowpaths in the connected pore are represented by streamlines which are calculated from the velocity map obtained from fluid flow simulation by means of Lattice Boltzmann Method. The streamline that is calculated with Euler Methods produce coordinates of the flowpath in the connected pore which are then used to calculate the tortuosity. The streamline are verified in a simple porous medium. The complexity analysis is verified on three simple models showing significant differences in complexity levels. The streamline generated using euler methods is suitable for the porous medium. The relation of the tortuosity and the permeability is tested in two porous medium that the permeability is known. It is found that the more complex the pore structure, the greater the tortuosity value. The hydraulic tortuosity is also inversely proportional to the permeability.
The magnetic susceptibility analyzes of Motonuno lake sediment in Muna Regency, Southeast Sulawesi, Indonesia
Authors: Jahidin  , Ngkoimani L O , Ilmawati W O S , Salihin L M Iradat , Irawati  , Usmardin  , Firman Al , Harisma  , Okto A
Published: August 2019

Study on the magnetic susceptibility, magnetic mineral, and content of element contained in the sediment has been done at Motonuno Lake Sediment in Muna Regency, Southeast Sulawesi Indonesia. Sediment samples in the form of cores were taken from three different sites by using the gravity core tool. Measurement of the magnetic susceptibility values was carried out by using the MS2C susceptibilitymeter. Content of element in the sediment was measured by using the SEM-EDX tool. The results showed that the magnetic susceptibility of sediment is -1 x 10−5 SI to 3 x 10−5 SI (site 1) and -2 x 10−5 to 2 x 10−5 SI (site 2 and site 3). Based on the value of magnetic susceptibility, the dominant magnetic mineral in the three sediment cores is pyrite (FeS2) which is an authgenic magnetic mineral. All three sediment core samples show that magnetic susceptibility values tend to be higher at the bottom of core than the top of core. This means that the sediment deposition takes place on different climate conditions, namely dry climate and wet climate. The elements contained in the sediment consists of O, Ca, Si, S, Al, Na, Cl, Fe, Mg, Au, Ti, Co, Cu, and Ni. All magnetic informations obtained in this study are very important in the understanding of paleoclimate condition at Motonuno Lake and its surrounding areas.
Study of integrated treatment of used bleaching earth cake from lubricant oil recycling process
Authors: Yuliana P T , Moersidik S S
Published: August 2019

“Used Bleaching Earth Cake (UBEC)” is the bleaching earth which has been used and filter pressed from the lubricant oil recycling industry. Comprehensive treatment required to treat UBEC as hazardous waste. This research tested the physical and chemical characteristics of UBEC to acknowledge its potential as engine fuel, and then UBEC was combusted in rotary kiln as refuse derived fuel (RDF). The bottom ash from the combustion process was used as fine aggregate replacement in concrete K350 production, compressive strength and Toxicity Characteristic Leaching Procedure (TCLP) was analyzed. UBEC consists of bleaching earth material (Monmorillonite 53.3% and Klinoptilolith 40%), oil residue, and impurities (heavy metals, carbon residue, etc.). Its calorific value ranges from 3000 to 5000 calories and meet the standards for being used as RDF. The average compressive strength result by replacing fine aggregate with 0%, 5%, 10%, 15% and 20% of its ashes were 31.88 MPa, 34.15 MPa, 38.45 MPa, 37.66 MPa, and 36.69 MPa, respectively. The highest compressive strength was at 10% of replacement. TCLP results still meet the standard. Overall, UBEC can be use as RDF and its bottom ash can be safely use as replacement for fine aggregates in concrete K350 production.
The effect of x-ray micro-ct geometrical zooming on the microstructure properties of porous medium
Authors: Ramadhan F W , Latief F D E
Published: August 2019

Digital rock physics has evolved rapidly due to its various advantages such as being able to see rock images in 3D without non-destructively. In this study, 3D images of porous medium sample were generated from X-ray micro computed tomography scanning device SkyScan 1173. This study aims to investigate the effect of X-ray Micro-CT geometrical zooming (sample position to the X-Ray source) on the microstructure properties of porous medium such as porosity, specific surface area, tortuosity, permeability and grain size distribution. The rocks tested were concrete sand samples. The distance between source and object was varied 3 times. The scan was processed through reconstruction process until thresholding. Porosity, specific surface area and grain was calculated by CTAn software. Tortuosity was calculated by finding the path at 26 neighboring pixels and the permeability was calculated by simulating a steady state fluid flow. The result is the greater the distance between the radiation source and the object, the smaller the resolution of the image. This causes some pores that are too small that eventually are grouped into rock matrix. Therefore, pore-related properties such as porosity and specific surface area will decrease, tortuosity will increase and permeability will decrease.
Environmental management in Citarum Watershed inter-institutional cooperation approach
Authors: Brotosusilo A , Budidarmono  , Utari D , Handayani R D
Published: August 2019

Some environmental issues in Indonesia are remaining problems that cannot be resolved. One among the environmental concern is a growing interest in the Watershed (DAS) area management. Various attempts had been made to manage the areas but has not resulted in optimal outcomes so far. The aim of this study is to determine the implementation of environmental management in Indonesia, especially in Citarum Watershed area. Through this research, it is expected in the future inadequate supervisory system that had been developed within the community can be converted into better management, such as integrated management of watersheds with the culture of everyday life. This research uses a mixed method approach consist of quantitative and qualitative analysis. The data is obtained from the modification approach of previous research on Kutai National Park combined with an interview with experts from government and academics. Furthermore, the data is analyzed using AHP (Analytical Hierarchy Process) and ANP (Analytical Network Process) Superdecision software Ver. 2.6. The study resulted that the strategy of environmental management should be changed into civil-military based management. To be able to map out a strategized effort the military involvement is required at the stage of planning, implementation, coordination, and supervision.
Correlation between gravity and magnetic data and its impact for geological structural phenomena in Kuningan, West Java, Indonesia
Authors: Nur A A , Harja A , Supriyana E , Nugraha G U
Published: August 2019

Kuningan district is located in the eastern part of west java province. It has uniquely geological feature. In the western part of this district is dominated by volcanic products from the eruption of mount ciremai, while in the eastern part it is dominated by tertiary rocks formation. Geophysical investigations have been conducted to identify subsurface phenomena in eastern part of Kuningan i.e. Lebakwangi sub-district. The results showed that the fault zone has a magnetic anomaly value and bouguer anomalies are inversely proportional, the higher the magnetic value the lower the bouguer anomaly value. faults have a tendency towards the northwest - southeast. The study area tends to be covered by the young volcanic deposits of mount ciremai eruption that overlay the tertiary rocks beneath it so that the existence of the faults tends to be disguised. The inverse geophysical data has an impact on the interpretation of the existing fault structure at the study area where the hangging wall footwall tend to be disguised. Need further geological and geophysical research to further identify the presence of faults in this study area.
Microearthquake relocation hypocenter using Modified Joint Hypocenter Determination (MJHD) method. (case study: Opak fault)
Authors: Zahwa F , Fattah EI , Hasanah M U , Wijatmoko B
Published: August 2019

Earthquakes with small magnitude and shallow depths are one form of manifestation of existence a fault line in Yogyakarta. Accurate hypocenter determination is needed to identify tectonic and fault conditions based on earthquake hypocenter distribution recorded by seismograf. Hypocenter was determined by using two methods Geiger’s Adaptive Damping for early hypocenter and Modified Joint Hypocenter Determination (MJHD) for relocate hypocenter, we used 2 weeks aftershock data after main quake occurred on June 10-14 2006 with total of 625 events earthquake obtained from the results of picking waves. The difference of hyposenter result on the longitude and latitude is about 2 -25 km and depth change around 0.3-5 km with major distribution to the east from the fault. The final result of this relocation shows that the area is more easily releases energy is in the eastern section of the fault consisting of sedimentary rocks.
Gravity data of porong regions, sidoarjo in the interpretation geology structure and deformation of the subsurface
Authors: Supriyana Eddy , Padmawidjaja Tatang
Published: August 2019

Patterns of regional geological structure Sidoarjo has performed detailed interpretation of gravity data is is controlled by the data of surface deformation via GPS. Indication of field data is not obtained a description pattern shallow geological structure being covered by sediment aluviumnya. Gas effuent or subsidence in the Siringbarat and Tanggulangin area is field evidence as controls in the estimation of interpretation of gravity changes and pattern density shallow geological structure. Regional and detailed gravity data interpreted that as an anomaly patterns are trending fault structures with the location of the gas effluent south southwest - north northeast. South trending regional fault structure of the southwest - north north-east to the surface to form a continuous fracture and amblasan as a medium in which the effluent gas is formed. Negative changes in the value of gravity is interpreted as a weak zone or zones shown as mass loss as subsidence located in Siringbarat and Tanggulangin. While positive changes in microgravity, as the removal of the zone located in the southern part of the Sidoarjo Mud pond.
Land cover modelling of Pelabuhanratu City in 2032 using celullar automata-markov chain method
Authors: Akbar Fadhli , Supriatna
Published: August 2019

Pelabuhanratu located in strategic coastal area, make it as the Centre of Growth in Sukabumi District. In this regard, landcover changes continue to occur and could trigger unsustainable environmental. The purpose of this study is to analysis the land cover change of Pelabuhanratu city until 2032. The Cellular Automata-Markov is used to identify the spatial growth, several factors that encourage the landcover change used as an input. The driving factor was build based on fuzzy logic, the variables are proximity to road, proximity to river, proximity to coastline proximity to point of interest, elevation, slope and landcover. Then, suitability area for built up area as input for Cellular Automata-Markov tools. Landcover was obtained from google earth in 2002, 2010 and 2017 then used as the basis for model calculation. The prediction result shows that land cover change in Pelabuhanratu city is very significant with the Kappa Standard level reach 91% accuracy. Built up area has extended from the previous condition that coming from agricultural area. Moreover, the area growth with linear pattern at south area, spread pattern at north area and crowded at west area.
Value-chain distribution of seaweed production in Amal Coast, Tarakan Island
Authors: Wahyularassati Annisa , Susiloningtyas Dewi , Handayani Tuty
Published: August 2019

Seaweed has high economic potential which is can give a hope for coastal societies to improve their living standards. Since 2009, In Tarakan island, North Kalimantan especially In Amal’s Coast, the local communities started to developing seaweed cultivation and now seaweeds become one of Tarakan’s main commodity beside fish, shrimps and crabs. This study aims to analysis seaweed’s value chain distribution in Amal Coast, Tarakan. Data collection method is interview directly to farmers, collector traders and other marketing agents by using snowball sampling. The marketing Chains occurred trough 2 Value Chains Channel and the farmers get less profits than the factories or exporter. Therefore, it is indeed needs to improve the value chain distribution of seaweeds in Amal coast.
Model of regional vulnerability against CO2Toxic Gas disasters at Mount Dieng (case study: Timbang Crater, Batur Sub-District, Banjarnegara District)
Authors: Syafrudin Rizqi , Tambunan Mangapul P , Supriatna
Published: August 2019

One of the sub-districts that are vulnerable to toxic gas disasters is Batur Subdistrict, Banjarnegara District.For that people living in the vicinity of the crater should always be ready for the national disaster of toxic gas that had killed 149 people on February 20, 1979 did not happen again.The purpose of this research is to make the model of vulnerability of area to toxic gas disasters of CO2 Timbang crater in Batur Sub-District by using Analytical Hierarchy Process (AHP).The population in this study is the entire head of the family located in Batur Sub-District, Banjarnegara District, Central Java Province, amounting to 37 heads of household.To take the sample used Simple Random Sampling method.Data analysis techniques through weighting of the three aspects are exposure, sensitivity, and adaptive capacity.In each aspect the parameters are weighted using input from the experts by the AHP method.The vulnerability of the area to the toxic gas catastrophic CO2 is classified into three levels of vulnerability are, low, medium, and high. Based on the research result, the vulnerability level in Batur sub-district is only divided into two classes, namely for the vulnerability class being found in 6 villages are, Pekasiran Village, Pesurenan, Sumberejo, Karang Tengah, Bakal, and Dieng Kulon. For the high grade, there are 2 villages: Batur, and Kepakisan. This happens because the level of exposure and sensitivity is much higher than the adaptive capacity of the community.
Elastic Property Modeling Related to Pore Type Analysis in Carbonate Reservoir
Authors: Dewa Made Raditya Margenta I , Winardhi Sonny
Published: August 2019

The reservoir has a significant role as a place of hydrocarbon accumulation in a petroleum system. Therefore, during exploration, a good understanding of the reservoir characterization becomes important to recognize the hydrocarbon migration path. There are several types of reservoirs which are commonly found; one of them renowned as carbonate reservoir. This type of reservoir is hard to be understood due to the heterogeneity of its pore type as a result of intense cementation and diagenesis. Information of pore type can be obtained based on core analysis or rock physics analysis. There are some rock physics approaches commonly used such as Kuster-Toksöz, Self Consistent Approximation (SCA), and Differential Effective Moduli (DEM). On the other hand, there are also other approaches but less famous. Parameters such as spherical porosity(ɸS
), pore shape parameters –pore shape factor (S) and relative pore shape factor(ΔS) – are sensitive to identify pore type which may be developed in a carbonate reservoir. A positive value of ɸS
and ΔS is the characteristic of carbonate rocks with the domination of stiff pore (high aspect ratio). These characteristics also can be informed by a value of S > 1. On the opposite, a negative value of ɸS
and ΔS is the characteristics of carbonate rocks dominated by soft pore (low aspect ratio) that also can be informed by a value of S < 1. These parameters offer a simpler approach about pore type analysis and easier compared to Kuster-Toksöz in rock physics modeling. This research will use synthetic data to comprehend each parameters and real data to validate a hypothesis based on synthetic data. The results obtained in this study can be used as a first step to do seismic inversion based on the elastic property which is sensitive enough for this condition.
Geotechnical Investigation Using Surface Waves Method: A Case Study of Sabet Bridge, Lamno, Aceh Province, Indonesia
Authors: Jamaluddin Khaizal , Nawawi Mohd , Rusydy Ibnu , Irwandi Irwandi , Chairullah Banta
Published: August 2019

Sabet bridge is a connecting bridge between Lamno town and Jantho town in Aceh Province. The bridge is located in a mountainous area and geologically near to a karst formation. The surface is covered by a fluvial landscape which was deposited by coarse sand, gravels, pebbles, and boulders. The bridge foundation analysis consists of four points cone penetration test which capable to penetrate up to 2 meters. One borehole has an obstacle in penetrating due to gravel, pebble and boulder layers; which consume more drilling time and expensive. To solve this problem, a seismic surface waves method has been performed. Two seismic lines run above the planned site of bridge abutment. The investigation reveal the results, that the surface waves method can penetrate into subsurface more than 30 meters in depth; in which the requirement depth only 30 meters. The results from surface waves method reveal the suitability and high similarity with cone penetration test and borehole investigation methods.
Realistic Shakemap M6.5 Pidie Jaya Earthquake 7 December 2016 Based on Modal Summation Technique
Authors: Irwandi Irwandi , Indris Yunita , Muksin  , Jamaluddin Khaizal , Zulfakriza  , Joni  , Muzli
Published: August 2019

The shakemap were usually generated based on strong ground motion calculations on attenuation equations of the Ground Motion Prediction Equation (GMPE). However, the GMPE is a general equation which does not take into account the structural model of each layer of the subsurface. It considers only the structure of the surface layer known as Vs30 calculated as amplification in shakemap calculation. In this paper, the realistic calculation of shakemap for Pidie Jaya earthquake of 7 December 2016 with magnitude M6.5 is performed. Shakemap is generated from a number of synthetics seismogram calculations from source to site-based capital calculation summation Technique. Neo Deterministic Seismic Hazard Analysis (NDSHA) has included in the calculation of the synthetics seismograph. Before engaging the Vs30 effect, the realistic shakemap capable of producing effects of the angular distribution of a double-couple model in a realistic calculation. This could give an advantage of realistic shakemap while the GMPE based shakemap had not taken into account the double couple model. The realistic calculation of modal summation technique for shakemap can be further developed by involving local structural models in a more comprehensive manner.
Rock Physics Template Application on Carbonate Reservoir
Authors: Hilman Judy , Sonny Winardhi Ignatius
Published: August 2019

A good characterization of a reservoir is required to understand its properties. One of the methods known is Rock Physics Template (RPT). This method attempts to characterize a reservoir in order to predict the behavior of the reservoir under different porosities and water saturation. However, most of RPT technique applications are limited to granular rocks and not for carbonates. Although carbonates generally suitable as reservoir rocks, it is proven to be more challenging. The complex system of carbonates porosities often gives scatter pattern on the correlation between porosity and P-wave. Therefore, this research attempt to use RPT to model carbonate reservoir. We use Kuster Toksoz as the basis for carbonate rock modeling with the help of the Biot-Gassmann equation. The target of this paper is the Baturaja formation that is located in South Sumatra Basin. This formation is known to be a carbonate reservoir that has produced gas hydrocarbon. This study offers an approach on how to better understand the application of RPT on carbonate formation. Based on the RPT modeling done in this research, specific parameters need to be obtained in order to develop a functional RPT model. These parameters are the aspect ratio of the porosities and the elastic modulus of the minerals.
Preliminary Result of Hypocenter Relocation Using Double Difference Method along Sumatran Fault, Indonesia
Authors: Surya Putra Ade , Dian Nugraha Andri , Puspito Nanang T , Triyoso Wahyu
Published: August 2019

The Sumatran fault zone has a high seismicity and seismic hazard threat levels due to this fracture through densely populated areas. The fault zone of Sumatera has 19 main segments which each segment has the possibility to generate a strong earthquake. Therefore, in this study we attempt to improve the accuracy of hypocenter locations which is needed as basic analysis in advance seismology and in seismic hazard analysis. The final objective of this study is to analyze the subsurface seismic velocity structure of the Sumatran fault by applying seismic tomography method. For the preliminary result, we have been conducting double-difference method to relocate 967 events recorded by 49 stations compiled by Meteorological, Climatological, and Geophysical Agency of Indonesia (MCGA) from 2009 to 2017 along Sumatran fault. Our preliminary results from the relocation proces indicate prominent features of event cluster around Sumatra fault system. The next step, we will improve the onset of P-and S-wave arrival time by using waveform cross-correlation in order to get more reliable hypocenter location.
Depth Migration Velocity: Differential Semblance Analysis for Sumatra Forearch Basin
Authors: Putra A. S. , Sismanto  , Alam I. S.
Published: August 2019

The specific goal of this work is to present a complete velocity map obtained by picking the velocity in Common Image Gather (CIG) map. We simulated a shot gather in order to obtain a synthetic travel time data for depth analysis. We successfully determined the correct migration velocity and presented the velocity interval model. For further study, we also conducted a Semblance analysis in order to obtain a coherency panel between the energy and the depth migration velocity analysis. We successfully interpreted the conventional semblance profile that the correct velocity model maximizes that energy which is represent higher value. For the real case, The data set was acquired by CGGVeritas in 2009 of RMS velocities recorded in 48 CMP points. The results of the semblance analysis shows well coherence with the seismic reflectance data that reveals the Low Velocity Zone of Sumatra fault related to the present of fluid and gas.
Production and Reinjection Evaluation on The Basis of 3D Time-lapse Microgravity Inversion
Authors: Haq F D , Sastranegara T , Agung L , Kusuma A D , Hendriansyah T , Fanani A F , Raharjo I B
Published: August 2019

An equilibrium in the geothermal is important especially in terms of reservoir sustainability. Fluid in the reservoir will continue to decrease if the reinjection activity unable to compensate the steam production. Field “US” is one of the geothermal field that has more than 5 Megaton production rate. The fluid depletion should be controlled so the reservoir is able to continue to supply the steam. Re-injection strategy plays an important role to keep up with the amount of fluid that comes out. Preparation of this strategy requires 4D microgravity or time lapse microgravity method to know which area has the most fluid depletion. The use of microgravity for monitoring has become the ultimate method in geothermal. In this paper, we will discussed on how advanced microgravity processing able to be a consideration in the production and re-injection strategy. The data used in this paper is microgravity survey which conducted every year from 2015 - 2017. Further processing such as inverse modelling is also used in this paper to estimate the mass changes inside the area of interest. In the modelling, we used staggered grids as an initial model to produce more suitable final model. Initial models are made based on geophysical research data such as Magnetotelluric resistivity data and hypocenter from Micro-earthquake so the position of the top reservoir can be determined. The Gauss’s Flux method also used in this paper to be compared with the result from inversion. The result of this research is to maintain the sustainability of reservoir in geothermal energy by make re-injection plans more effective and precise.
Binary Coded Genetic Algorithm (BCGA) with Multi-Point Cross-Over for Magnetotelluric (MT) 1D Data Inversion
Authors: Wijanarko E , Grandis H
Published: August 2019

The magnetotelluric (MT) 1D modelling has been continuously receiving interest due to its effectiveness in obtaining overall subsurface resistivity image of an investigated area. The advances in computational resources allow increasing implementations of non-linear inversion using global search approach, such as Genetic Algorithm (GA). The genetic algorithm adopts the process of natural selection (survival for the fittest) and genetic transformation, i.e. selection, reproduction, mutation and population change, to solve the optimization problem. This paper discusses GA application in MT 1D modelling using binary coding representation with multi-point cross-over, i.e. one for every model parameter. The model parameters are resistivity and thickness of homogenously horizontal layers. The algorithm parameters need to be set to work properly, i.e. population size, number of genes, number of bits, crossover probability, mutation probability and number of generations. Despite binary coded GA (BCGA) drawbacks discussed in the literatures, we found that binary representation allows relatively extensive exploration of the search space. Test using synthetic data from three-layered synthetic models lead to satisfactory results, in terms of synthetic model recovery and data misfit comparable with the noise level contained the synthetic data.
Full Waveform Modelling for Subsurface Characterization with Converted-Wave Seismic Reflection: Residual PP Removal on PS Component Using F-K Filter
Authors: Viony N C , Triyoso W
Published: August 2019

The application of converted-wave seismic method in hydrocarbon exploration has increased significantly. Since the conventional seismic ceases to provide an adequate image in complex geology area and it often provides an ambiguous bright spot response. The main principle is that an incident P-wave produces reflected and converted P and SV wave on an interface. Converted-wave seismic uses the multicomponent receiver that records both of vertical component and horizontal component. The vertical component is assumed to correspond to the compressional PP wave and the horizontal correspond to the PS converted-wave. In this and previous research (Viony and Triyoso, 2018), a synthetic seismic data with the shallow gas and the salt dome model are constructed by the full-waveform modelling. The purpose of this study is to improve the imaging quality on the PS section and the PS AVO curve due to the existence of the residual PP events on the horizontal data in the previous study (Viony and Triyoso, 2018). The PS gather has been NMO corrected by the PP velocity. Therefore, the residual PP reflections are well-corrected and the PS reflections are under-corrected. To obtain the more reliable PS data, the residual PP reflections have been removed by rejecting the well-corrected data in f-k filtering process. The results of this study present that the imaging quality and the AVO of the filtered PS is better and more reliable than the un-filtered PS in the previous study (Viony and Triyoso, 2018).