bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical study of sediment erosion in guide vanes of a high head Francis turbine
Authors: Acharya N. , Trivedi C. , Wahl N. M. , Gautam S. , Chitrakar S. , Dahlhaug O. G. 
Published: August 2019

Abstract
Erosion in guide vanes (GVs) has been reported from several power plants in Himalayan and Andes basins which affects the efficiency of turbine. Wear in clearance gaps (CGs) increases with the sediments passing through them resulting in increased gap size, which disturbs the flow into the runner inducing more losses. This paper investigates the flow and erosion pattern around GVs along with the leakage flow. Simulations are carried out in full GV and runner model with varying CGs with the inclusion of sediment. 3 types of clearance gaps viz., 0.5 mm, 1 mm and 1.5 mm are included and numerical results obtained are compared with the photograph of the erosion affected guide vanes. Result shows that erosion was prevalent in regions downstream of the mid-chord position inside the CG due to high pressure difference between two sides of GVs and the leakage flow induced from the pressure difference mixes with the main flow forming a vortex filament, which is driven towards the runner inlet.
Assessment and Numerical Analysis of Hydropower Tunnel in Lesser Himalayan Region of Nepal- A Case Study
Authors: Sundar Khadka Shyam , Karki Sujan , Chhushyabaga Bimal , Kumar Maskey Ramesh 
Published: August 2019

Abstract
This paper is focused on the assessment and numerical analysis of hydropower tunnel of the Lesser Himalayan Region of Nepal. This region lies between two major faults namely Main Boundary Thrust (MBT) and the Main Central Thrust (MCT) with weak rock mass like phyllite, schist, gneiss, phyllitic schist, etc. Thus, to overcome the stability problems during underground construction, proper rock support system must be installed. Rock mass classification systems are commonly used for estimating the rock support system in this region, but this approach is inadequate to address the underground stability problems. In this study, numerical analysis is done to define the requirement of support and the result compared to actual support provided in selected case study. Analytical approach is used along with two-dimensional Finite Element Analysis using the software, RS2 provided by RocScience for the study. Finally, required modification of the provided support has been suggested to overcome the problem faced in the selected tunnel.
Development of an information model of a virtual space of a historically significant territory
Authors: Gorelov I , Nemtinov V , Nemtinova Y 
Published: August 2019

Abstract
The article examines the questions of creating a virtual space of a historically significant territory as a means of communication and effective civil and patriotic education of young people. The proposed formal description of the model of the virtual space includes the sum of knowledge about a historically significant area (a historical site) presented in the form of a graph structure of frames. The creation of a virtual space in the form of a virtual museum is carried out using an open source software platform OpenSimulator 0.9.0, which is a server platform for 3D virtual worlds. Visualization of the museum is available to all Internet users. Thus, a thematic information environment has been created to provide access to relevant information and contributes to the growth of youth interest in the problems of national culture, history, and civil culture. In addition, an important role is played by the social aspect, as within the virtual world users can interact with others, observe their movements and actions, and communicate with them in real time.
Digital transformation of learning processes and the development of competencies in the virtual machine-building enterprise environment
Authors: Pozdneev B , Tolok A , Ovchinnikov P , Kupriyanenko I , Levchenko A , Sharovatov V 
Published: August 2019

Abstract
The paper presents the results of the pilot project “Virtual Machine-Building Enterprise”. It was developed for multi-level learning to meet the needs of the national digital economy and the digital industry. The profile of requirements for end-to-end learning (baccalaureate - magistracy - postgraduate) of prospective personnel in the digital development of machine-building enterprises has been substantiated. E-Portfolio model has been developed in accordance with the requirements of the standards GOST R 57720-2017 and ISO/IEC TR 20013:2015 to manage the digital competency development in the learning process and practical activities. The pilot project “Virtual Machine-Building Enterprise” was implemented at the initiative of MSUT “STANKIN”. It is a corporate technological platform for the digital machine-building development with the participation of industry, IT sector and technical universities. The architecture and functional model of a virtual enterprise are developed taking into account the principles of Industry 4.0, fundamental standards in automation systems integration (ERP, MES, CRM, CAD, CAE, CAPP, PLM, etc.) and e-learning (LMS, CMS, etc.). The educational programs are developed in accordance with the requirements of the FSES 3++, Professional Standards and qualification requirements for Chief Digital Officer. In the future, the pilot project “Virtual Machine-Building Enterprise” should be the basis for the formation of a digital technological university model.
Development of an online application for determination of thermo-physical properties of substances
Authors: Egorov S , Nemtinov V , Nemtinova Y , Egorov E 
Published: August 2019

Abstract
The article deals with development of a web application for determining thermo-physical properties of substances. A distinctive feature of the application is in using the method of forming functional dependencies in order to determine thermodynamic properties of a working medium for the regions of their liquid, steam, and gas phases that have first-order discontinuities at the inter-phase boundaries. The software package for mathematical modeling of thermodynamic processes, which includes a web application, is considered. Reference systems and computing services for performing mathematical calculations online are described. Examples of procedures used in the application to determine the properties of substances on the experimental data tables are given. The areas of using the application are identified.
Composite version of B&B algorithm: experimental verification of the efficiency
Authors: Groppen V O , Berko A A 
Published: August 2019

Abstract
The aim of this paper is to verify the efficiency for a composite version of branch and bound algorithm combining B&B branching strategy and bounds computing with the pruning rules used in dynamic programming for selecting of direction of movement by a search tree. As criteria of efficiency we used random access memory (RAM) and time gains of finding integer programming problem solution by a composite version of branch and bound algorithm in comparison with its traditional implementation. The number of variables in the problems and restrictions did not exceed 25 and 15, respectively. Experimental verification have shown that for solving time used as a criterion of the efficiency, the advantages of composite version are beyond doubt compared to the used RAM value as criterion often taking the side of the classical B&B algorithm.
Mathematical modeling of the synthesis process of vinyl acetate
Authors: Arapov D , Tikhomirov S , Podvalny S , Denisenko V , Avcinov I 
Published: August 2019

Abstract
A complete mathematical modeling of the technological process of manufacturing vinyl acetate monomer by vapor-phase method has been implemented. The model is partial differential equations of the material and energy balance and catalyst aging. An algorithm for an integrated equation based on the second-order Gregg-Bulirsh-Shter rectangle symbol has been developed. The error in modeling the process is equal (CH3COOCH=CH2) ± 5.4% rel. for the target matter, and (CO2) ± 6.4% rel. for the secondary substance The kinetic coefficients of differential equations, namely the pre-exponential factors and the activation energy have been refined. The obtained data of the modeling of the vapor-phase manufacturing process of vinyl acetate are shown in the form of tables and graphic three-dimensional dependencies of quality indicators on technological parameters.
Significant feedbacks of wetland methane release on climate change and the causes of their uncertainty
Authors: Gedney N , Huntingford C , Comyn-Platt E , Wiltshire A 
Published: August 2019

Abstract
Emissions from wetlands are the single largest source of the atmospheric greenhouse gas (GHG) methane (CH4). This may increase in a warming climate, leading to a positive feedback on climate change. For the first time, we extend interactive wetland CH4 emissions schemes to include the recently quantified, significant process of CH4 transfer through tropical trees. We constrain the parameterisations using a multi-site flux study, and biogeochemical and inversion models. This provides an estimate and uncertainty range in contemporary, large-scale wetland emissions and their response to temperature. To assess the potential for future wetland CH4 emissions to feedback on climate, the schemes are forced with simulated climate change using a ‘pattern-scaling’ system, which links altered atmospheric radiative forcing to meteorology changes. We perform multiple simulations emulating 34 Earth System Models over different anthropogenic GHG emissions scenarios (RCPs). We provide a detailed assessment of the causes of uncertainty in predicting wetland CH4–climate feedback. Despite the constraints applied, uncertainty from wetland CH4 emission modelling is greater that from projected climate spread (under a given RCP). Limited knowledge of contemporary global wetland emissions restricts model calibration, producing the largest individual cause of wetland parameterisation uncertainty. Wetland feedback causes an additional temperature increase between 0.6% and 5.5% over the 21st century, with a feedback on climate ranging from 0.01 to 0.11 Wm−2 K−1. Wetland CH4 emissions amplify atmospheric CH4 increases by up to a further possible 25.4% in one simulation, and reduce remaining allowed anthropogenic emissions to maintain the RCP2.6 temperature threshold by 8.0% on average.
Are e-scooters polluters? The environmental impacts of shared dockless electric scooters
Authors: Hollingsworth Joseph , Copeland Brenna , Johnson Jeremiah X 
Published: August 2019

Abstract
Shared stand-up electric scooters are now offered in many cities as an option for short-term rental, and marketed for short-distance travel. Using life cycle assessment, we quantify the total environmental impacts of this mobility option associated with global warming, acidification, eutrophication, and respiratory impacts. We find that environmental burdens associated with charging the e-scooter are small relative to materials and manufacturing burdens of the e-scooters and the impacts associated with transporting the scooters to overnight charging stations. The results of a Monte Carlo analysis show an average value of life cycle global warming impacts of 202 g CO2-eq/passenger-mile, driven by materials and manufacturing (50%), followed by daily collection for charging (43% of impact). We illustrate the potential to reduce life cycle global warming impacts through improved scooter collection and charging approaches, including the use of fuel-efficient vehicles for collection (yielding 177 g CO2-eq/passenger-mile), limiting scooter collection to those with a low battery state of charge (164 g CO2-eq/passenger-mile), and reducing the driving distance per scooter for e-scooter collection and distribution (147 g CO2-eq/passenger-mile). The results prove to be highly sensitive to e-scooter lifetime; ensuring that the shared e-scooters are used for two years decreases the average life cycle emissions to 141 g CO2-eq/passenger-mile. Under our Base Case assumptions, we find that the life cycle greenhouse gas emissions associated with e-scooter use is higher in 65% of our Monte Carlo simulations than the suite of modes of transportation that are displaced. This likelihood drops to 35%–50% under our improved and efficient e-scooter collection processes and only 4% when we assume two-year e-scooter lifetimes. When e-scooter usage replaces average personal automobile travel, we nearly universally realize a net reduction in environmental impacts.
Correlation and coherence analysis between sea surface temperature (SST) and surface wind in the Equatorial Western Sumatra Waters
Authors: Hatmaja R B , Wisha U J , Radjawane I M , Tanto T Al 
Published: August 2019

Abstract
Equatorial Western Sumatra Waters have a tremendous dynamic in ocean characteristics. It directly faces the Indian Ocean exactly located below the equator. Consequently, Equatorial Western Sumatra waters are influenced by the tropical climatic factors such as monsoons and climate variabilities, such as Indian Ocean Dipole (IOD) and Madden Julian Oscillation (MJO) that control sea surface temperature (SST) fluctuation in the Indian Ocean regions. This study aimed to review the correlation and coherence of SST distributed by surface wind in the Equatorial Western Sumatra waters. Wavelet method (cross wavelet transforms and wavelet coherence) was used to analyze the correlation and coherency between SST and surface wind. The annual variation of SST for 365 days period is the strongest event throughout the year caused by either monsoon or the changes of wind speed in the surface. Otherwise, the strongest intra-seasonal SST variation of 35 - 60 days observed from December 2012 to March 2013. The highest surface wind speed occurs in the southern and western waters. The surface wind plays a role in evoking SST distribution of 35 - 60 days period (intra-seasonal variability). Besides, the surface wind with 6 months period (semi-annual variability) influences the SST distribution which is identified only in the southern waters and the Indian Ocean regions. These conditions are possibly predicted as the influence of monsoons.
Diurnal variation of stable isotopes in rainfall observed at Bengkulu for the YMC-Sumatra 2017
Authors: Ichiyanagi K , Suwarman R , Belgaman H A , Tanoue M , Uesugi T , Warjono  
Published: August 2019

Abstract
Diurnal variability of stable isotopes in precipitation and its controlling factors are poorly understood, especially in the tropics. This study investigated the diurnal variability of stable isotopes in rainfall observed at Bengkulu in southern Sumatra, Indonesia. Rainfall samples were collected at 6-h intervals from 1 December 2017 to 15 January 2018 for the Year of the Maritime Continent (YMC-Sumatra 2017). The oxygen and hydrogen isotopic compositions δ18O and δH) of the rainwater varied from –15.1%o to –1.8%o and from –108.9%o to –1.3%o, respectively, and the d-excess varied from 1.9%o to 17.1%o. The observations at Bengkulu revealed that diurnal variation in rainfall amount was not significant for the entire period; however, the δ18O was lighter in both the early morning and the afternoon and heavier before noon and overnight. The δ18O became gradually depleted in the periods of continuous rain that occurred during 1–4 and 21–24 December. The amount of morning rain was much greater than evening rain in these periods, whereas the amount of evening rain was greater than morning rain in other periods. Based on satellite-derived CMORPH data, it is assumed that morning rain and evening rain corresponded to weak rainfall over surrounding sea region and strong rainfall over inland regions of Sumatra, respectively. The differences in moisture source and ratio of stratiform/convective rain rate between morning and evening might affect the isotopic composition of rainfall in the tropics.
The Effect of an Active Phase of the Madden-Julian Oscillation on Surface Winds over the Western Coast of Sumatra Island
Authors: Wu P , Ardiansyah D , Mori S , Yoneyama K 
Published: August 2019

Abstract
This study examined the effect of an active phase of the Madden-Julian Oscillation (MJO) on surface winds over the western coast of Sumatra Island using surface meteorological observations, meteorological radar observations, and balloon sounding data obtained from the Years of the Maritime Continent (YMC) Sumatra 2017 field campaign. Wind gusts (sudden and large increases in surface wind speed with durations of several to tens of minutes; squall) were observed frequently at Bengkulu from late November to early December 2017 during a local active phase of the MJO. The wind gusts occurred simultaneously with heavy precipitation when the eastward propagating convection from the Indian Ocean moved over the observation site. Upper air observations showed strong northwesterly winds in the lower troposphere in the 1,000–4,000 m layer. The surface wind gusts extended from the surface up to an elevation of 560 m, with the highest wind speed occurring approximately 300 m above the ground. Small changes in surface air pressure were observed during the wind gusts. The results suggested that momentum transfer from the upper atmosphere by downdrafts was the main cause of the surface wind gusts on the western coast of Sumatra Island during an active phase of the MJO.
Characteristic of anabatic wind in Bandung basin observed by AWS
Authors: Kombara P Y , Junnaedhi I D G A , Riawan E 
Published: August 2019

Abstract
A field campaign has been done for the wet season in 2015 to identify the pattern of local circulation such as anabatic wind at Bandung basin. In this field campaign, the Automatic Weather Stations (AWS) were installed at seven points from the north until the south region of Bandung basin. The result of this research defines the pattern of anabatic wind in Bandung basin into three categories: the pattern on weak convection, strong convection, and strong convection with rain event. On weak convection condition, after 12.00 LT, the anabatic wind tended to move to the north region of Bandung basin. The wind still moved to the north and south region, on strong convection and strong convection with rain event condition after 12.00 LT. However, after 15.00 LT the wind on strong convection with rain event changed to become northward. On strong convection and strong convection with rain event, the pattern of anabatic wind was influenced by the convective activity in the north and south region of Bandung basin. Whereas on weak convection condition, the pattern of anabatic wind was not influenced by the convective activity.
The evaluation of drought indices: Standard Precipitation Index, Standard Precipitation Evapotranspiration Index, and Palmer Drought Severity Index in Cilacap-Central Java
Authors: Balbo F , Wulandari R A , Nugraha M R R , Dwiandani A , Syahputra M R , Suwarman R 
Published: August 2019

Abstract
The Cilacap Regency-Central Java, is the largest agricultural area with a high level of drought vulnerability. This study aims to evaluate three indices in quantifying a drought condition in Cilacap Regency and its application in forecasting. The indices that were used in this study are Standard Precipitation Index (SPI), Standard Precipitation Evapotranspiration Index (SPEI), and Palmer Drought Severity Index (PDSI). The comparison between SPI and SPEI shows that there is no significant difference in terms of determining the drought severity. SPEI should be used when there is a temperature difference more than 2°C in 30 years. PDSI may provide more frequency of drought event and a good result in indicating the effects of drought on agricultural productivity. We used Climate Forecast System Version 2 (CFSv2) to predict drought severity by SPI. The result of model prediction shows that there is no significant improvement in accuracy before and after statistical bias correction. The prediction can be done on three months (lead3) before initial planting.
Preliminary result of characteristic of convective cloud development observed by x-band meteorological radar in bandung basin
Authors: Syaraswati R A , Trilaksono N J , Nugroho G A 
Published: August 2019

Abstract
The initial, mature, and dissipation stage changes in a convective cloud development have a short period of time so that the development stage analysis is needed by using data that has a high temporal resolution. The data that used are product CAPPI-V and CAPPI-Z from X-Band meteorological radar and also BBWS Citarum rainfall data from 13 stations that scattered in the area of Bandung basin. The selection of rainfall days is done to take the areas that have a strong convective system, and the result is that Sapan area has higher rainfall than 12 other stations on April 27th, 2017. The precipitation is caused by convective clouds. The initial stage of convective clouds begins with the existence of convergence phenomena in the afternoon and at 10 minutes before the rainfall event. It is also when there are maximum rainfall events on April 27th, 2017 which can indicate the formation of convective clouds. After the formation, the development stage occurs when there is an increase in reflectivity values on the radar and then convective cloud size starts to grow. When convective cloud size is dissipating, there is an identification of a decrease in reflectivity of the previous value in the evening. There is a new convective initiation next to the cloud that is in the dissipation stage and then joins to develops in a short time for about 30 minutes.
Identification of Mesoscale Convective Complex (MCC) Over Bangka Belitung Area
Authors: Saragih R W , Hestiwi A H , Sari F N Indah , Winarso PA 
Published: August 2019

Abstract
Mesoscale Convective Complex (MCC) is a mesoscale cloud convective system characterized by large, long-lived and quasi-circular pattern. The existence of MCC may trigger extreme weather events such as heavy rains which cause floods and landslides around the center of interest area. This paper aims to identify the presence of a storm cloud system which is observed as the MCC. For that purpose, this study used Himawari-8 satellite infrared channel data. Case of the study is the rain event in Bangka Belitung on 8 February 2016 which recorded 183.9 mm rainfall a day. Satellite data was processed using image processing software by applying MCC cloud system identification algorithm based on its physical characteristics, i.e. peak cloud temperature, coverage area, central point of cloud, cloud eccentricity and ellipse fitting, and lifetime of the cloud system. The final result of this study is able to yield the coordinates of latitude and longitude of MCC location, which are MCC cloud systems appeared around Bangka Belitung. This result confirmed that the occurrence of heavy rain on February 8th, 2016 in Bangka Belitung was caused by the presence of MCC around the interest area.
Analysis of ultraviolet index, ultraviolet B insolation, and sunshine duration at Bandung in year 2017
Authors: Hamdi S. 
Published: August 2019

AbstractUltraviolet index, ultraviolet B insolation, and sunshine duration in 2017 have been analyzed at Bandung, Indonesia (106.6 W and 6.9 S). The daily maximum ultraviolet B insolations have been grouped in ten-daily sequence following BMKG’s method in determining of dry/rainy season. Ultraviolet index classified following small modification WHO’s classification. Sunshine durations are clustered in 3 levels of exposure. It is found the average of sunshine duration in range 4.1-8 hours/day has 50% occurrence in 2017, meanwhile ultraviolet index more than 10 have been recorded in 46% occurrence in 2017, even of average of maximum ultraviolet B insolation is about 1.22 W/m2, and maximum intensity on 2017 is 2.17 W/m2. Both of ultraviolet index and maximum ultraviolet B insolation have a similar pattern on 2017 and the minimum value is on aphelion.