bluuebunny/crossref_metadata_2025_split huggingface dataset:
Black Material Deposition in Surface Facilities During Commissioning in Muara Laboh Geothermal Field
Authors: Azka Ghilman , Alfiady  , Azis Herwin , Aulia Nurul 
Published: April 2021

Abstract
Muara Laboh geothermal field is located in West Sumatra, Indonesia. The installed capacity is 80-85 MWe and already accomplished the Commercial Operation Date (COD) in December 2019. Prior to COD, several programs were conducted: pre-commissioning and commissioning programs. During these activities, some findings were encountered and one of the major findings was the black material deposit at several spots. The black material found from HP separator drain, condensate drain port and then ended up beneath the cooling tower basin. Based on the laboratory analysis, the SEM-EDX data shows that the material dominated by magnetite (Fe-Ox) and pyrite (FeS2) for the strainer sample. Meanwhile, the sample from HP separator contains some amount of silica, Arsenopyrite, anhydrite, and carbon. The occurrence of Fe-Ox might indicate the source of the black material coming from industrial goods, which caused by steam flow activity during the pre-com and commissioning program. Thus, the fact that no black material found during well testing from all wells also supports the theory.
Volcanostratigraphy Study of Slamet Volcano and the Implication to Its Early Stage of Geothermal Exploration
Authors: Assiddiqy Muhamad Hasbi , Gati Rai , Sibarani Betseba , Suryantini  
Published: April 2021

Abstract
The application of volcanostratigraphy has been broadly used on many early stages of geothermal exploration. The method is simple yet powerful to give a preliminary suspicion on geothermal potential before a field survey. By combining contour analysis in certain scale (1:50,000 and 1:100,000) such as ridge and river pattern with the stratigraphic analysis of volcanic product the volcanostratigraphy units are determined. In this study, the volcanostratigraphy units were assessed using geothermal potential evaluation scheme for a stratovolcano to determine the potential of a geothermal green field.As the object of the study, a quarternary stratovolcano of Slamet Volcanic Complex in Central Java region was analyzed. Eight volcanostratigraphic units were determined in Slamet Volcanic Complex area and its surrounding, including six crowns and two hummocks. In addition, the hydrothermal fluid from several manifestations within the Slamet Volcanic Complex area (warm springs) were analysed to characterize the potentials of Slamet Volcanic Complex Region. Based on these determined volcanostratigraphy units,the occurrence of hydrothermal manifestation within the defined volcanostratigraphy units, the result of hydrothermal fluid analysis, and the criteria matching to the potential evaluation scheme for stratovolcano, the Slamet Volcanic Complex was categorized as potentially beneficial to be surveyed in detail. In such system, the volcanostratigraphy method is relatively simple and reliable to be applied since the volcanic evolution sequences data are accessible.
Geothermal Prospect Review in the Western Part of Salak Volcano, West Java, Indonesia
Authors: Aprilina Nur Vita , Golla Glenn U. , Kusumah Yudi Indra , Suryantini  
Published: April 2021

Abstract
The Ertankian Geothermal Prospect is located in the southern area of Bogor District, West Java, Indonesia. From 1982 through the end of 1983, Unocal Geothermal of Indonesia, Ltd. (UGI) conducted extensive geological, geochemical, and geophysical surveys that outlined Ertankian as a potential geothermal field on the flanks of the Salak Volcano. This volcano forms the north-eastern part of the Salak-Perbakti-Gagak Volcanic Massif, which consists of Upper Pleistocene to Recent stratovolcanoes, parasitic vents, and phreatomagmatic craters. The exploration survey included, magnetotelluric and gravity surveys, water geochemistry, thermal manifestation gas, ion, and isotope analyses, and geological, photo-geological interpretation, and photogrammetry interpretation. Kawah Ertankian is a vigorous fumarole area with numerous superheated and boiling steam vents, boiling acid sulfate hot springs, and large areas of acid-altered ground. Elemental sulfur is common around many of the vents. Steam from the Ertankian Fumaroles contains 7 mol% H2S and the maximum reservoir temperature obtained from the NAH-CO2 gas geothermometer was 525°F. The Ertankian Hot Springs have acid sulfate character and yield little information about the underlying hydrothermal system. Bicarbonate chloride warm springs occur on the northern flanks of the Salak Volcano at northwest and northeast locations and interpreted as the outflow product of Ertankian Geothermal System. Extensive areas of low resistivity are distributed across most of the Ertankian Geothermal Prospects. Low resistivity zones are observed around the Kawah Ertankian thermal manifestation complex and broaden to the far northwestern warm spring and Gunung Perbakti in the southwest. The shallowest base of the conductor is observed in the area near Kawah Ertankian and probably extends towards the northwest in the Alpha-19 well area. Towards the south and southwest, a significant deepening of base of the clay cap is observed. The observed resistivity trend coincides with and parallels to the NW-SE South and North Ertankian Faults, which may be the outflow pathway of the hydrothermal system. The lower rock conductance values and deepening of the clay cap base toward the southwest indicate a lower possibility of connection to the main Salak geothermal system. Considering the geological, geochemical, and geophysical data, the Ertankian Geothermal Prospect is presumed to be an encouraging area for further studies.
Magnetotelluric Data Analysis Using Phase Tensor and Tipper Strike to Determine Geoelectrical Strike in “DKH” Geothermal Field
Authors: Maswah Fauziah , Suryantini  , Srigutomo Wahyu , Fajri Reza Jamil , Pratama Angga Bakti , Pratomo Prihandhanu M. 
Published: April 2021

Abstract
The magnetotelluric (MT) method is passive geophysical method that measures natural electromagnetic field to estimate the subsurface resistivity structure. Before conducting 2D MT data inversion, data analysis, dimensionality, including determining the direction of the geoelectrical strike must be performed. It is needed to fulfill the assumption of 2D MT modeling. 2D modeling of magnetotelluric data is an important part because the results can determine the quality of the subsurface interpretation. Therefore, this paper describes the determination of the dimensonality and geoelectrical strike using the phase tensor and tipper strike parameters. The invariant parameters of phase tensor including skew angle (β) and ellipticity are used to get the information about the dimensionality and geoelectrical strike. The results from the phase tensor are plotted in a rose diagram to determine the main direction of the geoelectrical strike. The phase tensor analysis contains ambiguity 90°, therefore tipper strike used to validate the analysis. From the analysis, the result shows the 1D or 2D structures of the MT data in high frequency, meanwhile the lower frequency, the majority of the data show 3D structures. The dominant geoelectrical strike is around N15°E and it is confirmed with the regional structure of the area. Determination of dimensionality and geoelectrical strike are applied to MT data from the geothermal field.
Performance Evaluation of Geothermal Power Production Using EES (Case Study Ulumbu Geothermal Power Production Unit 4 East Nusa Tenggara, Indonesia)
Authors: Ediatmaja Prajamukti , Darmanto Prihadi Setyo , Maulana Dimas Taha 
Published: April 2021

Abstract
Ulumbu geothermal working area (GWA) is in Ruteng district, East Nusa Tenggara province, Indonesia. Ulumbu GWA is owned by PLN. There are four geothermal power plants (GPP) in Ulumbu, which capacity 4 x 2.5 MW. It has operated since 2013. Steam used to generate electricity comes from ULB-2 production well. Wellhead temperature and pressure were 180-200°C and 11 bar. Ulumbu GPP Unit 4 uses a condensing type turbine. It has specific steam consumption (SSC) during commissioning around 9.8 T/MW. After 6 (six) years of operation, SSC becomes 10.04 T/MW on average. It gives a chance to perform optimization in the GPP’s equipment. Before performing optimization, evaluation for every equipment based on as-built data is done by modeling using EES software. The method of evaluation is performed by thermodynamics analysis in each GPP’s equipment. EES is chosen due to its simplicity to arrange many equations in a single window. EES could communicatively display calculation results through a parametric table, solution window, and diagram window. Operation data give information that turbine inlet pressure is operated under its specification. Turbine inlet pressure is operated under its specification because of the change of operating wellhead pressure. Non-Condensable Gas (NCG) content also decreases based on the last ULB-2 well fluid sampling. Using EES, parameter changes in turbine inlet pressure and NCG content are simulated to get optimum power generation value. The simulation results indicate that optimum turbine inlet pressure is obtained at 9.3 bar with SSC 9.17 T/MW. Ulumbu GPP Unit 4 that operated in that condition could reach cycle efficiency of about 10.39%.
The Implementation of Flow Performance Test to Monitor Well Performance in Geothermal Field
Authors: Sugiharto Mochamad Permadi , Marastio Fadiel Evan , Fanani Ahmad Fahmi , Pasaribu Fernando , Silaban Marihot , Maulana Dimas Taha , Saptadji Nenny Miryani 
Published: April 2021

Abstract
Reservoir monitoring of a geothermal field has an important role in determining the direction of company policies in managing a geothermal field, one of which needs to be monitored is by looking at changes in the pattern of the deliverability curve so that it can determine changes in the characteristics and performance of production wells. In order to update the deliverability curve, it is necessary to conduct periodic production tests. However, this cannot be done due to limited steam reserves. This research was conducted to determine the performance of production wells using the Flow Performance Test (FPT) method. This method is an alternative solution that can update the production well deliverability curve without leaving the gathering system. The FPT is applied to UBL-DL5 and JL2, UBL-JL3 is shown to validate the equations used. The data obtained were validated with TFT data and production test data where the deviation of the data obtained for UBL-DL5 was 1.42%, UBL-JL2 was 2.7%, and UBL-JL3 was 2.74%. The comparison of the UBL-DL5 and JL3 models based on time shows a significant production decline, and this is possible because the wells have only been operating within a period of 4 months – 1 year where the condition of production wells are still looking for stable condition, while the UBL-JL2 have not been seen there is a change in characteristic. The FPT is reliable enough to be used as an alternative method in monitoring production wells compared to the TFT method and the horizontal lip pressure production test. The FPT program should be conducted periodically and synchronized with the company’s operational activities plan. The delivery curve modeling as FPT result is used to monitor production wells’ condition as the basis for the company to develop a dynamic five-year work plan.
Approach for Pre-Feasibility Study of Medium Enthalpy Geothermal Field, Case Study: Danau Ranau, Indonesia
Authors: Rera Gladiez Florista , Pratama Heru Berian , Saptadji Nenny Miryani 
Published: April 2021

Abstract
The development of geothermal fields in Indonesia is carried out under the provisions of the applicable laws and regulations, namely Geothermal Law No. 21 of 2014 and Environmental Protection and Management Law No. 32 of 2009. Based on Law No. 21 of 2014, geothermal business activities consist of preliminary surveys, exploration, and exploitation. After the exploration phase (a detailed geological, geochemical, and geophysical study), a pre-feasibility study is needed to determine the feasibility of exploration drilling. The pre-feasibility study is done to manage project risks. Danau Ranau geothermal field is one of the 166 medium enthalpy geothermal prospects in Indonesia. Activities carried out in this field were geoscience studies. This research was conducted to determine how feasible the Danau Ranau medium enthalpy geothermal field was developed for direct and indirect utilization by looking at the acceptance of technical, financial, environmental, and risk studies. The study can be a tool for the developer to decide whether to continue the next development stage. The result shows that applying the approach for Danau Ranau Geothermal Field is feasible to develop with consideration. Plant of Development by cascade model with leveling utility of energy for Danau Ranau Geothermal Field shows optimal value both in the operational and financial sides. The first level is technically designed for electricity with ORC conversion technology and the cascade level for indirect use by Lindal Diagram and community empowerment in economic and social. In financial analysis, the cascade model has optimum profitability value expressed in NPV and equity IRR.
Application of Artificial Intelligence in Forecasting Geothermal Production
Authors: Wardoyo Galih Kusumo , Pratama Heru Berian , Sutopo  , Ashat Ali , Yudhistira Yodha 
Published: April 2021

Abstract
A reservoir is the main asset of a geothermal business. Decreasing reservoir performance affects the sustainability of production in the future. In planning future production strategies, forecasting production projections are used with the assumption of particular parameter values. A reservoir is a porous media with a heterogeneous nature with a high degree of uncertainty, so using a specific production forecasting method’s assumption parameter becomes inaccurate. This study aims to develop alternative methods for optimizing and estimating geothermal production by eliminating assumptions. Artificial intelligence (AI) is an alternative method that can be used to predict reservoir productions that has properties with a high degree of uncertainty and can be used to optimize production. The AI model was created using measurement data of production parameters at the steam dominated geothermal field in Patuha, Indonesia. AI models in estimating geothermal reservoir production are more accurate in calculating production projections because they use real field data and eliminate assumptions.
Study of Increase Geothermal Well Production Rate by Downhole Pump Installation for Utilization in Power Plant
Authors: Prabowo Ricky , Saptadji Nenny Miryani , Maulana Dimas Taha , Nusiaputra Yodha Yudhistra 
Published: April 2021

Abstract
A geothermal well is one of the main components in the geothermal field. The well is essential for geothermal utilization and connecting between reservoir and surface. Based on the condition to discharge fluid toward the surface, wells are categorized as self-discharge wells (able to discharge naturally to surface) and non-self-discharge wells (not able to discharge naturally to surface). For wells categorized as non-self-discharge with low pressure and low-medium temperature, an artificial method needs to be implemented, which is the use of downhole pump technology, namely electrical submersible pump (ESP) or line shaft pump (LSP). This condition occurs in well in Tulehu geothermal field (X-1). Downhole pump technology has been developed in several geothermal fields in other countries and has been proven to increase geothermal well production. The purpose of this research is to determine the appropriate engineering design for the implementation of a downhole pump in X-1 well and the net power output that can be produced. The research method was carried out analytically from evaluating and analyzing well-testing results, including completion test and production test to determine the condition and characteristics of the well, performing technical design calculation for downhole pump implementation, and calculating the binary cycle analysis of power plant obtain net power generated. Optimum pump setting depth in 600 meters depth that can produce mass flow rate 48.28 kg/s, and optimum model is ORC power plant with Butane working fluid that can produce Net Power Output 1.382 MW for ORC power plant model combined with ESP-2.
Updated Numerical Model of Mataloko Geothermal Field
Authors: Jatmiko Bambang Wahyu , Pratama Heru Berian , Sutopo  
Published: April 2021

Abstract
Data collection and further geoscience studies have been carried out in the Mataloko area at the end of 2019. In general, the results of the study showed significant differences compared to previous studies. Therefore, it is necessary to update the Mataloko geothermal field’s numerical model following the latest studies’ data and analysis. In this research, numerical modeling will be performed using a TOUGH2 V.2 simulator and graphical interface software. The model will be built and validated at the natural state phase. It is expected that the model can complement existing geoscience studies and can be used by developers in planning field development.
Updated Conceptual Model and Resource Assessment using Numerical Reservoir Simulation of Danau Ranau Geothermal Field Indonesia
Authors: Afiat  , Idianto Onny , Rera Gladiez Florista , Wardoyo Galih Kusumo , Sutopo  , Pratama Heru Berian , Hamdani Muhammad Ridwan 
Published: April 2021

Abstract
Danau Ranau geothermal field is located in Lampung and South Sumatra province, Indonesia. It is classified as a high terrain volcanic hydrothermal system controlled by the Sumatran fault as the permeability zone. The study aims to characterize the Danau Ranau reservoir, update the conceptual model, and assess the geothermal power capacity coupled with Monte Carlo simulation. Therefore, the numerical reservoir simulation is performed using TOUGH2 software to achieve a natural state model based on geoscience interpretation data. The numerical reservoir models’ output matches the geological, geochemical, and geophysical interpretation, thus becoming important information (3D pressure and temperature, heat and mass flow, location of heat source, boundary condition, reservoir geometry) in the updated conceptual model. The probabilistic heat stored method results based on the natural state model’s output show that Danau Ranau geothermal field can generate up to 30 MW.
Boundary extension as mental imagery
Authors: Nanay Bence 
Published: April 2021

AbstractWhen we remember a scene, the scene’s boundaries are wider than the boundaries of the scene we saw. This phenomenon is called boundary extension. The most important philosophical question about boundary extension is whether it is a form of perceptual adjustment or adjustment during memory encoding. The aim of this paper is to propose a third explanatory scheme, according to which the extended boundary of the original scene is represented by means of mental imagery. And given the similarities between perception and mental imagery, the memory system encodes both the part of the scene that is represented perceptually and the part of the scene that is represented by means of mental imagery.
Innovations for the future of breast surgery
Authors: Vidya R , Leff D R , Green M , McIntosh S A , St John E , Kirwan C C , Romics L , Cutress R I , Potter S , Carmichael A , Subramanian A , O’Connell R , Fairbrother P , Fenlon D , Benson J , Holcombe C 
Published: April 2021

Abstract

Background
Future innovations in science and technology with an impact on multimodal breast cancer management from a surgical perspective are discussed in this narrative review. The work was undertaken in response to the Commission on the Future of Surgery project initiated by the Royal College of Surgeons of England.

Methods
Expert opinion was sought around themes of surgical de-escalation, reduction in treatment morbidities, and improving the accuracy of breast-conserving surgery in terms of margin status. There was emphasis on how the primacy of surgical excision in an era of oncoplastic and reconstructive surgery is increasingly being challenged, with more effective systemic therapies that target residual disease burden, and permit response-adapted approaches to both breast and axillary surgery.

Results
Technologies for intraoperative margin assessment can potentially half re-excision rates after breast-conserving surgery, and sentinel lymph node biopsy will become a therapeutic procedure for many patients with node-positive disease treated either with surgery or chemotherapy as the primary modality. Genomic profiling of tumours can aid in the selection of patients for neoadjuvant and adjuvant therapies as well as prevention strategies. Molecular subtypes are predictive of response to induction therapies and reductive approaches to surgery in the breast or axilla.

Conclusion
Treatments are increasingly being tailored and based on improved understanding of tumour biology and relevant biomarkers to determine absolute benefit and permit delivery of cost-effective healthcare. Patient involvement is crucial for breast cancer studies to ensure relevance and outcome measures that are objective, meaningful, and patient-centred.
Plasma Microbial Cell-free DNA Next-generation Sequencing in the Diagnosis and Management of Febrile Neutropenia
Authors: Benamu Esther , Gajurel Kiran , Anderson Jill N , Lieb Tullia , Gomez Carlos A , Seng Hon , Aquino Romielle , Hollemon Desiree , Hong David K , Blauwkamp Timothy A , Kertesz Mickey , Blair Lily , Bollyky Paul L , Medeiros Bruno C , Coutre Steven , Zompi Simona , Montoya Jose G , Deresinski Stan 
Published: April 2021

Abstract

Background
Standard testing fails to identify a pathogen in most patients with febrile neutropenia (FN). We evaluated the ability of the Karius microbial cell-free DNA sequencing test (KT) to identify infectious etiologies of FN and its impact on antimicrobial management.

Methods
This prospective study (ClinicalTrials.gov; NCT02912117) enrolled and analyzed 55 patients with FN. Up to 5 blood samples were collected per subject within 24 hours of fever onset (T1) and every 2 to 3 days. KT results were compared with blood culture (BC) and standard microbiological testing (SMT) results.

Results
Positive agreement was defined as KT identification of ≥1 isolate also detected by BC. At T1, positive and negative agreement were 90% (9/10) and 31% (14/45), respectively; 61% of KT detections were polymicrobial. Clinical adjudication by 3 independent infectious diseases specialists categorized Karius results as: unlikely to cause FN (N = 0); definite (N = 12): KT identified ≥1 organism also found by SMT within 7 days; probable (N = 19): KT result was compatible with a clinical diagnosis; possible (N = 10): KT result was consistent with infection but not considered a common cause of FN. Definite, probable, and possible cases were deemed true positives. Following adjudication, KT sensitivity and specificity were 85% (41/48) and 100% (14/14), respectively. Calculated time to diagnosis was generally shorter with KT (87%). Adjudicators determined real-time KT results could have allowed early optimization of antimicrobials in 47% of patients, by addition of antibacterials (20%) (mostly against anaerobes [12.7%]), antivirals (14.5%), and/or antifungals (3.6%); and antimicrobial narrowing in 27.3% of cases.

Clinical Trials Registration
NCT02912117

Conclusion
KT shows promise in the diagnosis and treatment optimization of FN.