bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure of turbulent natural convection in a heated rapidly rotating inter-disk cavity with near-axis heat sinks
Authors: Smirnov Sergei , Smirnov Evgueni , Kolesnik Elizaveta 
Published: July 2021

Abstract
The paper presents the results of implicit LES numerical analysis of natural convection developing in a rapidly rotating inter-disk cavity with the width-to-radius aspect ratio equal to 0.13. The convection under study is developed under conditions of a prescribed temperature distribution over the disk surfaces and heat removing action of two near-axis volume sinks of a proper intensity. The thermal conditions are defined on the base of experimental data available in the literature for the prototype case of mixed-convection flow in a cavity heated from the side of the disk surfaces with axial throughflow of cooling air. The computations were carried out for the Ekman layer equal to 0.28· 10−4, if evaluated with the cavity width. Using the closed-cavity model with near-axis heat sinks, principal features of the flow structure and heat transfer, revealed previously for the prototype case of mixed convection have been reproduced successfully, including formation of a pair of global cyclonic/anticyclone vortices and a cold flow core of nearly constant temperature. It is shown also that each near-disk shear layer can be subdivided into a relatively thin highly gradient “internal” Ekman-type layer and a much thicker “outer” layer, which thickness is of the same order as the thermal layer thickness. For the case considered, groups of elongated regular structures occur within the outer layer that can be detected by analyzing the low-speed fluid motion in the axial direction. Further studies are needed to reveal physical reasons of occurring these structures.
Influence of propeller diameter mounted at wingtip of high aspect ratio wing on aerodynamic performance
Authors: Vinogradov O N , Kornushenko A V , Pavlenko O V , Petrov A V , Pigusov E A , Ngoc Trinh Thang 
Published: July 2021

Abstract
In this paper, the propeller diameter effect on cruising characteristics of a solar-powered aircraft with a high aspect ratio wing is considered. Numerical studies were performed using a program based on the Reynolds-averaged Navier-Stokes equations for Mach numbers M=0.145 and Reynolds numbers Re = 0·3-106. Three aircraft configurations were considered: without propellers, with running two-bladed propellers with diameters of 0.22 m and 0.33 m. Numerical studies showed that the installed propeller introduces significant non-linearity into the lift curves and propeller thrust coefficient versus angle of attack curves. The propeller slipstream velocity field changes depending on the propeller advance ratio and the flow velocity, thus influencing the pressure distribution on the wing and the aircraft aerodynamic performance.
Mathematical model of the charging of thin aluminum film in the space plasma
Authors: Yakovlev A B 
Published: July 2021

Abstract
In this paper the generalization of model of a film charging which takes into account its bilateral form and partial permeability is made. Also the system of the equations for the determination of the density of the charge induced on the film surfaces is obtained and results of calculations of the charge density in plasma of a solar wind and in the radiation belt for different reflection factors of sunlight are given.
Generalized Chebyshev problem in nonholonomic mechanics and control theory
Authors: Yushkov M P , Soltakhanov Sh Kh , Dodonov V V 
Published: July 2021

Abstract
The paper is based on the talk with the same name given at the International scientific conference on mechanics “The Ninth Polyakhov’s Reading” dedicated to the 200th anniversary of the birth of the prominent Russian scientist Pafnuty Lvovich Chebyshev. The generalized Chebyshev problem is formulated, in which the motion of a system in the presence of given generalized forces should satisfy an additional system of linear differential equations in which the order of each equation exceeds three. These problems constitute a new class of control problems in which the motion program is given in the form of the above additional system of differential equations. These equations can be considered as linear nonholonomic constraints of high order, whose reactions are the desired control forces. To solve such problems, two theories were developed at the Department of Theoretical and Applied Mechanics of St. Petersburg University. In the first theory, we construct a consistent system of differential equations for the generalized coordinates and the Lagrange multipliers, which are considered as equitable unknown functions of time. The second theory is based on the generalized Gauss principle. The application of the theory is illustrated by the solution of a real space mechanics problem about the motion of an Earth satellite after fixing the value of its acceleration at some point in time. Especially efficient is the application of the second theory to the determination of the optimal control force for transferring a mechanical system with a finite number of degrees of freedom from an existing phase state to a new specified state within a specified period of time. The new method is used to solve the model problem of controlled horizontal motion of a cart bearing the axes of several mathematical pendulums. It is shown that the use of the generalized Gauss principle for solving this problem is undoubtedly superior to that of the classical Pontryagin maximum principle.
Long-term crop rotation diversification enhances maize drought resistance through soil organic matter
Authors: Renwick Leah L R , Deen William , Silva Lucas , Gilbert Matthew E , Maxwell Toby , Bowles Timothy M , Gaudin Amélie C M 
Published: July 2021

Abstract
Climate change adaptation requires building agricultural system resilience to warmer, drier climates. Increasing temporal plant diversity through crop rotation diversification increases yields of some crops under drought, but its potential to enhance crop drought resistance and the underlying mechanisms remain unclear. We conducted a drought manipulation experiment using rainout shelters embedded within a 36-year crop rotation diversity and no-till experiment in a temperate climate and measured a suite of soil and crop developmental and eco-physiological traits in the field and laboratory. We show that diversifying maize-soybean rotations with small grain cereals and cover crops mitigated maize water stress at the leaf and canopy scales and reduced yield losses to drought by 17.1 ± 6.1%, while no-till did not affect maize drought resistance. Path analysis showed a strong correlation between soil organic matter and lower maize water stress despite no significant differences in soil organic matter between rotations or tillage treatments. This positive relationship between soil organic matter and maize water status was not mediated by higher soil water retention or infiltration as often hypothesized, nor differential depth of root water uptake as measured with stable isotopes, suggesting that other mechanisms are at play. Crop rotation diversification is an underappreciated drought management tool to adapt crop production to climate change through managing for soil organic matter.
Utilization of alternative ingredients as combination feed on the growth of catfish (Clarias sp.)
Authors: Mukti RC , Amin M , Yulisman  
Published: July 2021

AbstractThis study aims to determine the effect of using alternative ingredients as a combination feed on the growth of catfish. This research was conducted in October - November 2020 which took place at the Laboratory of the Experimental Pond of the Departemen of Aquaculture, Sriwijaya University. The test fish used were catfish seeds measuring 5 - 6 cm. The study was designed with an experimental method in the form of a completely randomized design (CRD). The treatment to be used is a combination of commercial feed with alternative feed as many as 5 treatments with 3 replications, P0: commercial feed 100%, P1: combination of commercial feed 25% and alternative feed 75%, P2: combination of commercial feed 50% and alternative feed 50%, P3: combination of 75% commercial feed and alternative feed 25%, and P4: alternative feed 100%. Based on the results obtained, it shows that the use of alternative feed as a combination of feed has no significant effect on growth, feed efficiency and survival of catfish. The use of alternative feed as a combination feed of 50% (P2) has an effect on the growth and feed efficiency which is high in catfish of catfish. The growth of absolute length, absolute weight, and efficiency of fish feed produced were 1.67 cm, 4.20 grams, and 53.25%.
Isolation and Performance Testing of Bacillus subtilis As Biological Agents to Control the Diplodia Disease on Siam Citrus
Authors: Aprilia Dinda , Miftakhurohmat Agus , Sutarman  
Published: July 2021

Abstract
This study aims to determine the feasibility of the Bacillus subtilis isolate as a biological agent and the concentration of bacterial cells capable of controlling Diplodia in the Siamese citrus (Citrus nobilis). Isolation and biological agency testing on soil samples taken from horticultural land were carried out at the UMSIDA Microbiology Laboratory. The trial of the biological agency application was carried out in Talok Village, Dlanggu District, Mojokerto Regency. The application experiment was carried out in a randomized block design, with treatment in the form of bacterial cell concentrations in the application volume consisting of no biological agents, 10−7, 10−8, and 10−9 CFU.ml−1 in 100 ml. The experiment was repeated five times in order to obtain 20 experimental units. The experimental data were analyzed by ANOVA at 5% followed by the 5% HSD test. The results showed that the bacterial isolates of B. subtilis were found to be potential biological agents with the white rhizoid-shaped colony and dry surface, gram-positive, and non-pathogenic in nature. Biological agent B. subtilis with a cell concentration of 10−8 CFU.ml−1 in 100 ml of application solution gave the best effect to reduce the intensity of Diplodia disease in C. nobilis.
The correlation between mangrove ecosystem with shoreline change in Indramayu coast
Authors: Nur Sofyan Hasanuddin , Hilmi Endang 
Published: July 2021

Abstract
Mangrove ecosystem in Indramayu coast has function to preserve coastal area from abrasion and sedimentation as destructive hazard, because mangrove has ability to reduce impact of abrasion and sedimentation in coastal ecosystem. Before 2018, Indramayu regency had shore line coast until 115.5 km, but abrasion caused the degradation of shore line in Indramayu coast until more than 20%. This research aimed to analysis correlation between mangrove ecosystem with shoreline change in Indramayu Coast. The research method used vegetation analysis and mapping analysis. The results showed that (1) the degradation mangrove area was shown by mangrove areal 7688,38 ha (1990) to 862.20 ha (2016), (2) the shoreline change had potential abrasion reaches 255,2-277,65 ha and accretion reaches 40,6 – 315,9 ha. (3) the mangrove density reached 40-145 trees ha-1 (diameter >10cm) and 423-2238 trees ha-1 (diameter>4cm). (4) The optimum width of mangrove greenbelt to reduce coastal disaster and shoreline change in Indramayu between 200 – 250 m
Analysis of Overcurrent Safety in Miniature Circuit Breaker AC (Alternating Current) and DC (Direct Current) in Solar Power Generation Systems
Authors: Jamaaluddin Jamaaluddin , Sulistiyowati Indah , Reynanda BWA. , Anshory Izza 
Published: July 2021

Abstract
The sun is a source of energy and has advantages over fossil energy sources. This solar energy really needs to be researched and developed further. The use of solar energy is by installing a Photovoltaic Cell (PV) along with the Solar and Battery Control system. In short, it can be referred to as a Solar Power Plant (PLTS). This PLTS will be used in buildings as the Solar Building System (SBS). Completing this system requires a protection system management. The protection system known to the general public is the use of a Miniature Circuit Breaker (MCB). This MCB is intended for direct current and alternating current. To get a good protection system in PV mini-grid, how to use MCB and how to install it must be chosen. So that you will get a conclusion that the characteristics and level of efficiency are better than the two uses of the MCB.
The Application of Geostatistical Analysis on Radiometric Mapping Data to Recognized the Uranium and Thorium Anomaly in West Sulawesi, Indonesia.
Authors: Gde Sukadana I , Wayan Warmada I , Harijoko Agung , Indrastomo Frederikus Dian , Syaeful Heri 
Published: July 2021

Abstract
Mamuju Region in West Sulawesi, Indonesia is one of prospect area of uranium/thorium in Indonesia. High radiometric concentrations were located in Adang Volcanic Rocks. This formation is grouped as basaltic to intermediate rock and composed by lava, pyroclastic rocks, and tuff. Regional field radiometric mapping, including radiation dose rates, potassium, uranium, and thorium contents of soil and rock was conducted to identify the existence of radioactive minerals and prospect zones. Some radiometric anomalies are detected and probably related to hydrothermal alteration, leaching, and precipitation processes. Uranium anomaly (97,261 ppm) located in Mamuju River upstream, Botteng, Takandeang and Ahu area. The anomaly related to uranium leaching and precipitation processes in leucite basalt lava. Thorium anomaly (369,461 ppm) located in Pangasaan, Takandeang, Ahu, and Taan area. To expand this radiometric mapping, we characterized the reflectance of Landsat-8 imagery based on field measurement data. Based on circular structures identification, uranium/thorium anomaly are related to the existence of volcano vents on Adang Volcanic. Based on band rationing, high uranium contents distributed in the area with less ferromagnesian mineral, while thorium did not affect. These field based and remote sensing characterization results could be used as preliminary parameters to identify wide and detail prospects.
Causes, Dynamics, and Environmental Conflict Resolution Models in Coal-Fired Steam Power Plant Development Locations
Authors: Ishardanti Ria , Herdiansyah Herdis , Seda Francisia Saveria Sika Ery 
Published: July 2021

Abstract
This paper examines the causes, dynamics, and models of environmental conflict resolution that can be applied in the construction of a coal-fired steam power plant. The existence of power plants is a dilemma because it has negative impact to the society and environment that can lead to conflict. Environmental conflicts always begin with ecological degradation which becomes increasingly complex due to social factors. Discussions of environmental conflicts often focus on ecological damage but forget about the social impacts that will result. The causes of conflicts such as competition for natural resources, poor management of natural resources and the environment, and the dynamics of natural resources that cross borders require proper conflict management to deal with them. This study offers management conflicts models in resolving social-environmental conflict.
Social-Ecological Vulnerability and Livelihood Improvement Strategies of Landslide Victims in Pattalikang Village, Gowa Regency in National Security Perspective
Authors: Adri Khairunnisa , Sumantri Siswo Hadi , Triutomo Sugeng , Sari Deffi Ayu Puspito 
Published: July 2021

AbstractLandslides are caused by natural environmental factors and cultural, environmental factors, such as changes in land use and social conditions. In the event of a landslide disaster in Pattalikang Village, the community had to start over from scratch and improve their livelihoods. This study aims to analyze: (1) the social-ecological vulnerability of landslide in Pattalikang Village; (2) disaster mitigation efforts for the people of Pattalikang Village after landslides; and (3) Strategies for improving the livelihoods of the people of Pattalikang Village after landslides from a national security perspective. This study used a qualitative approach with descriptive-analytical methods. Respondents are from the Pattalikang Village community and representatives from the head of Pattalikang village, the Regional Disaster Management Agency, the Social Service, the Agricultural Service, the Public Works and Housing Agency, and Tagana Gowa Regency. The results showed that: (1) The socio-ecological vulnerability in Pattalikang Village was categorized as vulnerable based on the scoring and weighting of socio-ecological vulnerability factors; (2) Mitigation efforts carried out were planting vetiver in every landslide-prone point and training of disaster risk reduction for community; (3) The strategy used by the communities who are victims of landslides is consolidation and survival strategy as the strength point to rebuild the communities and improving livelihoods after disaster.
Determination of priority locations for the implementation of rice farming insurance: a case study on disaster hazards in Cilacap regency
Authors: Pramukti Unggul , Suryanto  , Gravitiani Evi 
Published: July 2021

Abstract
In 2018, Cilacap Regency produced a total of 793,265 tons of rice, and was the second largest producer of the commodity in Central Java Province, after Grobogan Regency. However, Cilacap is very prone to flooding, thus is grouped into the high flood hazard category. The aim of this study is to determine the rice fields that need to be included in the Rice Farming Business Insurance program. It was conducted using an overlay and weighting or scoring method. The data were the Flood and Drought Hazard Maps obtained from the National Disaster Management Authority (BNPB), and the Rice Field Map obtained from the Geospatial Information Agency (BIG). The results showed that 17,251 ha of the rice farm land were in the priority I category, while 60,742 and 223 ha(s), were in the Priority II and III categories respectively. Furthermore, the sub-district that was most affected by the flood and drought was Kawunganten. In conclusion, the results can be used in the creation of priority policies for the Rice Farmers Business Insurance program
The distillation process of palm sap (Arenga pinnata MERR) to produce bioethanol
Authors: Ansar  , Nazaruddin  , Azis Atri Dewi 
Published: July 2021

Abstract
Aren palm (Arenga pinnata MERR) is a type of palm tree that grows in tropical forests, especially in South and Southeast Asia. There are 3000 species of palm and they are categorized as multipurpose trees because they were used as raw materials for various products, such as brown sugar, palm syrup, palm wine, vinegar, alcohol, and bioethanol. This study aims to examine the distillation process to produce bioethanol from aren palm. The research sample was obtained from local farmers in Sasaot Lombok, Indonesia. The process used to produce bioethanol is multilevel distillation. The raw materials are first fermented using yeast, charcoal, and lime with a variety of compositions. The bioethanol produced is used as a substitute fuel for a 4-stroke motorbike engine. The results showed that the composition of the fermentation mixture of 250 grams of yeast, 100 grams of charcoal, and 100 grams of whiting produced the highest levels of ethanol, namely 93%. This level of ethanol cannot be used in a 4-stroke motorbike engine properly because the motor rotation is unstable.
Determination of Level of Lead (Pb) and Cadmium (Cd) Migration on Bowl and Clear Plastic Cup Using Atomic Absorption Spectrophotometer
Authors: Riyanti Hurip Budi , Yeni Y 
Published: July 2021

Abstract
Food safety is a condition and efforts needed to prevent food from biological and chemical pollutants and other things that might irritate, harm, endanger human health. So the food is safe to consume. Besides, it should not against religion, faith, and culture. Chemical pollutants may come from migration of the food container or packaging, for example from a bowl or clear plastic cup. Migration happens as a result of the high temperature of food, duration of storage, and the production process. The higher the temperature the higher the possibility of migration. The existence of lead (Pb) and cadmium (Cd) in food may be because of environmental pollution, absorption of metal from equipment. Research has been conducted on the determination of the level of lead (Pb) and cadmium (Cd) from the migration of some bowls and plastic glasses that are available online by using spectrophotometer atomic absorption. The research is using acetic acid 4 % simulant. The sample is identified by using Near Infra-Red. The result of two kinds of plastic bowls and one kind of clear plastic cup are Polypropylene (PP). The sample is filled with acetic acid 4% simulant, stored in a dark place for twenty- four hours, then it is measured with Atomic Absorption Spectrophotometer (AAS). In all samples consist of two kinds of bowls and one clear plastic cup. The lead and cadmium are not detected with a limit of detection (LoD) Pb is 1.33 µg/ml dan (LoD ) Cd is 0.22 µg/ml, while the limit of quantitative (LoQ) Pb is 4.43 µg/ml and ( LoQ) Cd is 0.74 µg/ml. LoD dan LoQ for lead is too high because are using AAS Flame, while ideally using AAS Graphite Furnace.
Diversity of insect pollinator on farmland near to mount Ciremai National Park
Authors: Nurlaila Ai , Karyaningsih Ika , Herlina Nina , Nasihin Iing , Yudayana Bambang 
Published: July 2021

AbstractThe purpose of this study was to determine the diversity and abundance of insect pollinator and to determine the correlation of insect pollinator to the distance between farmland and the conservation area of Mount Ciremai National Park (MCNP). The method used is scan sampling. Traps were installed sequentially at intervals of 100m, with 5 observation points (100 m, 200 m, 300 m, 400 m, and 500 m) with 3 replications. There are 573 individual insects found, with a value of H '= 3.285 (moderate diversity). There are 94 individuals (relative abundance = 16.4%) were insect pollinator, consisting of 3 orders, 7 families, and 8 species. The pollinator species found were: Anopilus, Athyma perius, Campsomeris plumipes fossulana, Erynnis tages, Pison spinolae, Syrphus ribesii, Vanessa sp, and Xylocopa. The order of Hymenoptera was most found followed by the order of Lepidoptera and Diptera. The distance between farmland and the MCNP area has a positive correlation (r = 0.592) with the amount of pollinator, meaning that the amount of pollinator increases as the distance between farmland and the MCNP area increases. The distance between farmland and the MCNP area has a negative correlation (r = -0.576) with the amount of insect species, meaning that the distance the farmland to the MCNP area increasingly, more insect species are found.
Diversity and abundance of insect pollinator on dimocarpus longan l. in Sawitsari research station, Sleman, Yogyakarta
Authors: Riswanta Ultha Rifqy , Aditya Nico Chandra , Sobri Anas , Sukirno Sukirno 
Published: July 2021

Abstract
Kelengkeng Super Sleman (KSS) is a new variety of Dimocarpus longan L. developed at Sawitsari Research Station, Sleman, Yogyakarta. As the key of agroecosystems, insects play an important role in aiding the process of pollination of flowers. The research was aimed to study the diversity and pollination effectivity of insect pollinators on Kelengkeng Super Sleman (Dimocarpus longan L.) in Sawitsari Research Station, Sleman, Yogyakarta. The purposive sampling method including active and passive was used to explore the diversity of insect pollinators. Observation was conducted on three ranges of time, morning (08.00 to 09.00 am), noon (11.00 am to 12.00 pm), and evening (03.00 to 05.00 pm). The result showed that 19 families identified and 21 families unidentified from active and passive methods with Calliphoridae and Formicidae had the highest flower-visiting activity in the morning, noon, and evening. Besides that, uncovered panicles successfully pollinated with an average of 114 flowers, while covered panicles only 43 flowers. In conclusion, both Calliphoridae and Formicidae were the most KSS pollinators and the flower cover hinders the pollination process.