bluuebunny/crossref_metadata_2025_split huggingface dataset:
Introducing Colorimetric Analysis with Document Scanner for High School Students
Authors: Fatoni A , Supiani  , Dwiasi D W , Anggraeni M D 
Published: May 2020

Abstract
Spectrophotometer is modern analytical instrument for analysis the amount of substance based on the color change. However, for high school laboratory practice, only few schools had this instrument for chemical analysis. There are many studies reported the use of daily life electronic for colorimetric analysis such as smartphone, scanner and digital camera. This work demonstrated the used of document scanner for colorimetric glucose determination for easy learn the daily life instrument as analytical device. The color detection was based on the reaction of glucose with glucose oxidase enzyme to produce H2O2. The H2O2 was then reacted with TiOSO4 to produce yellow color. The color formation was captured with a document scanner and the digital image was analyzed using ImageJ software. The result of the used of document scanner showed Horwitz Ratio of 0.40, recovery of 98.4%, linear responses from 0.5 mM to 3.0 mM (r = 0,9989), limit of detection of 0.15 mM and limit of quantification of 0.40 mM.
Improved reuse and affinity of enzyme using immobilized amylase on alginate matrix
Authors: Zusfahair  , Ningsih D R , Kartika D , Kurniasih M , Nofiani R , Fatoni A 
Published: May 2020

Abstract
Enzyme immobilizations were widely used to increase their shelf life which is essential for the world’s industries. Therefore, amylase immobilized using Na-alginate as a matrix is necessary optimized and characterized. The parameters measured in the optimization of immobilization are the determination of the concentration of sodium alginate and contact time. Characterizations were conducted to determine the optimum concentration of substrate, the value Vmax, Michaelis-Menten constant (KM), pH, temperature, incubation time, and test reuse. The process of immobilized amylase activity test was performed in a continuous flow system using a reactor, and its sugar levels were determined using the Dinitro Salisilat Method (DNS). The results reveal that the immobilized amylase commercial has optimum concentration of Na-alginate of 5% (w/v) and contact time of 90 minutes with an immobilization efficiency value of 43.02%. Furthermore, the immobilized amylase has optimum activity at substrate concentrations of 3.5% (w/v), pH 4, incubation temperature of 40 °C, and a reaction time of 20 minutes with the value of the activity of 2760.4 U / mL. KM value of free amylase and immobilized amylase row are 0.18 mM and 0.15 mM, repectively. The value of KM immobilized amylase is smaller than the free enzyme. It proves that the immobilized amylase has a high affinity for the substrate. The immobilized amylase can be used up to 12 times with a value of the residual activity of 56.7%.
Application of High Performance Liquid Chromatography Method for Triadimenol Analysis in Water Sample
Authors: Hermawan D , Cacu  , Suwandri  , Fatoni A , Mudasir  , Aboul-Enein H Y 
Published: May 2020

Abstract
Triadimenol is the most important triazole fungicide used for prevention and treatment of plant fungal disease. A simple high performance liquid chromatography (HPLC) method for triadimenol analysis in water sample is reported in this study. The optimized HPLC system using C18 column was achieved using mobile phase composition containing acetonitrile-water (70:30, v/v), a flow rate of 1.0 mL/min, UV detection at 220 nm, and analysis time within 2.5 min. The calibration graph was linear in the range 5 to 50 mg/L with r2 of 0.9997. The limit of detection (LOD) and limit of quantification (LOQ) obtained were 1.23 and 4.12 mg/L, respectively. Combination of solid phase extraction (SPE) and the optimized HPLC method has been successfully applied for the determination of triadimenol in water sample with a recovery of 94.24 % (RSD = 5.38%, n = 4). The proposed HPLC method provides short analysis time, high reproducibility and high sensitivity.
The Effect of Multiplanes Graphene Flakes Coating on Ag Nanowire Transparent Conductive
Authors: Fiqalbi Nur , Dwi Cahyaningrum Ratih , Prihandoko Bambang , Harsojo  
Published: May 2020

Abstract
The performance of transparent conductive Ag nanowire (TCA) has the potential to replace the indium titanium oxide (ITO) glass. However, TCA suffered from environmental parameters such as humidity and temperature that may change its resistance and its transparency or its optical transmission. We study the effect of multiplanes graphite coated on the TCA. We fabricated the multiplanes graphite using hydrothermal process directly the solution of graphite flakes and cetyltrimethylammonium bromide. The synthesis of this process showing that the material was in the form of multiplanes graphite flakes (MGF). The coated MGF on the TCA and showing that there is an improvement in the resistance of the TCA although its optical transmission in the wavelength range of 300 nm-800nm decreased by about 40%. The best result showed that using one microgram MGF coated on 4cm2 TCA may change the resistance of the TCA changed from 4.5 MΩ/sq down to 0.17 MΩ/sq.
Study of Transparent Conductive of Ag Nanowire Under Ambient Environment
Authors: Dwi Cahyaningrum Ratih , Harsojo  
Published: May 2020

Abstract
Silver nanowire (AgNW) has the potential to be fabricated as a transparent conductive to replace the indium-tin-oxide (ITO) based glass. However, the transparent conductive suffered from environment effect due to the connectivity of the wires. In this study, we retested the properties of transparent conductive made about two years ago and study its resistance and optical transmission. The morphology was observed using a transmission electron microscope (TEM), and the crystalline was tested using XRD, while the resistance, as the quantity related to the conductance, as tested using a two-probe method, while the transmittance was measured using UV-VIS spectrometer. The result indicated that although the wire and the crystalline only slightly change the resistance changes dramatically due to the problem of connectivity between wires.
Estimation of Potential of Iron Sand in The Eastern Coastal Area of Cilacap Regency Based on The Local Magnetic Anomalies Data
Authors: Sehah  , Kurniawan M A , Andriyanto I , Arismawan B , Risyad A , Wibowo A M , Raharjo S A , Sugito  
Published: May 2020

Abstract
Estimation of potential of iron sand in the Eastern Coastal Area of Cilacap Regency, Central Java Indonesia based on the magnetic anomalies data has been carried out in March 2016 – October 2018. The research area covers five coastal areas, i.e. Widarapayung, Western Binangun, Eastern Binangun, Western Nusawungu, and Eastern Nusawungu. The results of the research which are acquired show that iron sand deposits are estimated to be discovered in all coastal areas, where the greatest potential is the Western Nusawungu Coastal and the smallest potential is the Eastern Nusawungu Coastal. The range of the local magnetic anomalies data of the Western Nusawungu Coastal area is -711,38 – 1701,84 nT, whereas the range of the local magnetic anomalies data of the Eastern Nusawungu Coastal area is -498,66 – 201,73 nT. The potential of iron sand is based on the range value of the local magnetic anomalies data of each research area, because the local magnetic anomalies data are directly assosiated to the magnetic properties of iron minerals.
CO oxidation through the formation of carboxyl intermediate on Pt(111) surface: A first principles study
Authors: Zulaehah S , Cahyanto W T , Fitriani I N , Abdullatif F , Widanarto W , Effendi M 
Published: May 2020

Abstract
The interaction of gas molecules with metal surfaces is extensively studied both theoretically and experimentally. An example of this interaction is the oxidation reaction of carbon monoxide (CO) by hydroxyl (OH) catalyszed by platinum (Pt) in the direct methanol fuel cells (DMFCs). Here, the work offers a simulation of the CO oxidation reaction by the formation of carboxyl group intermediates (COOH) based on the total energy calculation of density functional theory (DFT). The discussion here focuses on the energetics for the reaction of CO(ads) + OH(ads) → COOH(ads) and the decomposition of COOH(ads) → CO2(ads) + H(ads) on the Pt(111) surface. The calculation results show that the formation of COOH(ads) requires an energy of 0.39 eV, whereas the decomposition of COOH(ads) into CO2(ads) and H(ads) requires an activation energy of 0.14 eV. These results indicate that oxidation of CO by the COOH intermediate on Pt(111) surface is possible to occur, considering that the total energy required for the reaction is very low.
New phenomena with the f(R)-theory of gravitation in a central gravitational field
Authors: Van Ky Pham , Thi Hong Van Nguyen , Anh Ky Nguyen 
Published: May 2020

Abstract
The f(R)-theory (of gravitation) is an extension of Einstein’s general theory of relativity (GR) but if a spherically symmetric vacuum solution of the Einstein equation in the GR is always stationary, a spherically symmetric vacuum solution of an f(R)-theory is not necessary stationary. This may have interesting consequences. In comparison with the GR, a process such as a planet’s motion (its orbital precession and parameters) and a gravitational deflection of light now get a correction which is a constant for a static central field and varies with time for a non-static central field even from a source of a constant mass, unlike the corresponding GR value not changing in the same situation. In particular, a spherically symmetric source may radiate gravitational waves. This phenomenon cannot happen in the GR. The present work is an extended version based on a presentation in the 44th Vietnam conference on theoretical physics (Dong Hoi, 29 July - 01 August 2019).
Magnetic orders of Heisenberg models with arbitrary spin in semi-fermionic representation
Authors: Thi Thanh Nga Pham , Toan Thang Nguyen 
Published: May 2020

Abstract
In 1988 Popov and Fedotov (PF) proposed a new method for spin Hamiltonians free of the local constraint problem for spin S = 1/2 and S = 1. Later, this approach has been extended for arbitrary spin. PF formalism has been used to study magnetic orders in some spin S = 1/2 and S = 1 Heisenberg models. In this report we show how to study the low temperature phases of quantum Heisenberg models with arbitrary spin by means of PF method. We work out the analytical expressions needed for studying ordered phases of Heisenberg models in one-loop approximation.
Molecular dynamics simulation of amorphous silica under pressures
Authors: Trang G T T , Kien P H , Hung P K , Hong N V 
Published: May 2020

Abstract
Models of amorphous silica have been produced at 500 K, and in pressures range

0
÷
100

GPa by molecular dynamics simulation. Topological analysis is performed based on the basic units and transition to different a-types, where a is the Oxx
and Oxy
(x, y = 4, 5, 6). The simulation shows that the fraction of different types of basic units varies strongly and the mid-range structure modifies stronger than the short-range structure under pressure. In the

0
÷
100

GPa pressure range, structure of amorphous silica occurs the transformation from D4-to D6 domain which correspond to the intervals of

0
÷
5
,
5
÷
15

and

15
÷
100

GPa. We also found a number of O
456 connected with three different Si atoms. Upon compression, the structural change is accompanied with the

O

x
x

→

O

x
y

transition and two parallel processes: merging and splitting of domains which relate to the change of domain-boundary atoms.
Students’ representation based on high order thinking skills for the concept of light
Authors: Fatmaryanti S D , Ashari  , Wahidah V S 
Published: May 2020

AbstractLight is one of the concepts in physics which is close with daily life. This descriptive study aims to explore student representations in terms of high order thinking skills (HOTS) on the concept of light. The research subjects were 30 students of junior high school in Purworejo. Data collection techniques using a test with three items in the form of descriptions based on indicators of HOTS. The data obtained were analysed qualitatively and the presentation of data analysis results through tables. The results showed that there are three forms of students’ representation in understanding the concept of light, namely mathematics, picture and verbal representation. Image representation is the most commonly used concept of shadow while the concept of light propagation uses more verbal representation. The use of diverse representations in solving problems can facilitate the improvement of HOTS.
Effect of soil mass motion on nonlinear forced vibrations of beams on elastic foundation
Authors: Wang Man , Ma Jianjun , Han Shujuan 
Published: May 2020

Abstract
Based on the nonlinear equation of motion of the beam on the Winkler foundation with the consideration of finite-depth soil mass motion, the nonlinear forced vibrations of the beam were investigated. Applying the Galerkin method and the method of multiple scales, the frequency-response equation and the second-order approximate solution of the primary resonance of the beam were obtained. Then, by means of the numerical calculation and parameter analysis, the effects of parameters about the soil mass motion on the frequency-response curves of the beam on the Winkler foundation were explored, such as foundation depth, soil mass, and Winkler foundation stiffness. The results show that the effect of the soil mass motion on the nonlinear forced vibration of the beam on the Winkler foundation is significant. When the effect of soil mass motion is introduced into the equation of motion of the beam, the range and the softening behavior of primary harmonic resonance of the system are reduced.
Extreme hurricane rainfall affecting the Caribbean mitigated by the paris agreement goals
Authors: L Vosper E , M Mitchell D , Emanuel K 
Published: May 2020

Abstract
Hurricanes are among the most impactful extreme weather events affecting small island states such as the Caribbean and require long-term planning for community and infrastructure resilience. By coupling an offline dynamical hurricane model to the output of a large ensemble of global climate model simulations from the Half a degree of Additional warming Prognosis and Projected Impacts (HAPPI) project, we assess how the impacts of hurricanes may change under the Paris Climate goals. Specifically, we concentrate on hurricane rainfall over particular regions, with both the mobility and intensity of a hurricane being key drivers of local level impacts. For example, Hurricane Dorian (2019) caused widespread devastation when it stalled over Bahamas as a category 5 storm. We show that since 1970 only one other hurricane stalled at this strength: Hurricane Mitch (1998). Due to a combination of increased stalling and precipitation yield under a warmer world, our analysis indicates a greater likelihood of extreme hurricane rainfall occurring in the Caribbean under both Paris Agreement scenarios of 1.5 ∘C and 2 ∘C Global Warming goals, compared to present climate projections. Focusing on specific hurricane events, we show that a rainfall event equal in magnitude to Hurricane Maria is around half as likely to occur under the 1.5 ∘C Paris Agreement goal compared to a 2 ∘C warmer climate. Our results highlight the need for more research into hurricanes in the Caribbean, an area which has traditionally received far less attention than mainland USA and requires more comprehensive infrastructure planning.
Optimization of the thermal power plant operation by distributing exergy flows in the heat pump
Authors: Amerkhanov R A , Arakelyan N S , Dvorniy V V 
Published: May 2020

Abstract
The possibility of wide use in practice and implementation of optimization of a thermal and power plant on the basis of exergy analysis with the use of target functions are presented in the article. A tree of thermal economic costs of a solar thermal supply system with possible distribution of flows in a thermal and power plant with the representation of a block diagram is considered. The exergy characteristics of each element of the system are given in the form of dependence. It determines the exergy flux density of total solar radiation on the surface of solar collectors. The schedule of total solar radiation, average monthly air temperature and total exergy amount of the city of Krasnodar as well as the graphs of distribution of the price of 1kW of exergy for months of a year were taken into account. The distribution of exergy flows in the heat pump and its energy efficiency are estimated by the coefficient of conversion.
Justification of dependence of the sprinkler machine power supply system efficiency on the irrigation process parameters
Authors: Bakirov S M , Logacheva O V , Shlyupikov S V 
Published: May 2020

Abstract
The article considers the problem of choosing the power supply system of the sprinkler machine. The energy supply system can be represented by different types of the drive of the chassis of the machine: hydraulic, electrical and mechanical. Not only types of drives, but also whole systems in terms of an indicator – coefficient of performance (COP) are compared. The COP of the energy supply system takes into account the parameters of the irrigation process: the pressure of irrigation water at the entrance to the sprinkler machine (SM), the remoteness of the reservoir from the fixed support of the SM, the remoteness of the SM from the village. During the analysis, the dependencies of the COP of the hydraulic and electrical (powered from the cable line) systems on the parameters of the irrigation process were established. The conditions for ensuring the action of SM on a hydraulic drive are determined. It was found that the COP of the hydraulic system has a higher efficiency of up to 14.8% at a pressure created by the pump of more than 0.65 MPa with a distance of SM from the pumping station of not more than 4 km. In other conditions of irrigation, the efficiency of the electrical system is slightly higher – from 1.43% to 40.54%. For a reasonable choice of the energy supply system, other parameters should be taken into account, for example, the cost of the energy supply system, the lifespan of the SM, and others.
Influence of ozonation in seed storage on corn grain yield and its quality
Authors: Baskakov I V , Orobinsky V I , Gulevsky V A , Gievsky A M , Chernyshov A V 
Published: May 2020

Abstract
Ozonation makes it possible to disinfect the material and ensures rehabilitation of micro-damage, which increases the overall crop yield. The corresponding studies were carried out to confirm the theoretical prerequisites for the positive effects of ozonation of seed during storage. As a result, it was found that ozonation of corn seeds in grain storage silo increases their germination capacity: laboratory – by 4% and field – by 10%, relative to the control sample without any treatment. At the same time the weight of grain collected from plants which seeds were ozonized during storage exceeded the same indicator in the control sample by 13.4%, and the thousand-seed weight – by 12.8%. Ozonation of seed grain during storage allowed increasing the grain yield, equivalent to one sowing hectare at a seeding rate of 6 pcs/m – by 9.3 c/ha. Besides, the share of coarse fractions (with the diameter of more than 7 mm) in a grain heap obtained from plants grown from ozonized seeds exceeds the corresponding indicator in the control version by 7.3%.
Application of priority and delayqueuing system in non-stationary modes to determine the required number of repair personnel in rural distribution electric networks
Authors: Efanov A V , Os’kin S V , Yastrebov S S , Privalov E E , Bukreev A G 
Published: May 2020

Abstract
The paper considers the possibility of using a queuing system to determine the required number of repair and maintenance personnel in the event of mass failures in rural distribution electric networks. In this case, the separation of requirements for restoring failures (requests) into priority and secondary is used. The multi-channel queuing system is used with two priority levels, with the delay of both priority requests and secondary requests. The algorithm has been developed for composing a system of differential equations describing a given queuing system. The system of differential equations is solved by numerical methods, and, using a specially developed algorithm, based on the results of the solution for a given point in time, the required number of repair personnel is estimated based on such parameters as the probability of queuing and the average waiting time of requests in the queue. The developed algorithms have been implemented in software; the necessary number of repair personnel has been calculated with their use, as well as on the basis of statistical data on failures in rural distribution electric networks. Assessment of the intensity of the flow of priority and secondary requests has been carried out by two methods. In the first method the data from the dispatcher’s record book or acts of investigation of technological disturbances have been used. Failures were divided by such parameters as reliability categories of power supply for cut-off consumers, volume of cut-off load and social significance of cut-off objects. In the second method, those requests that could be fixed by the forces of the field service teams were priority, the remaining requests were considered secondary.
Modeling of the power of the drive of the spiral mixer
Authors: Konovalov Viktor V , Teryushkov V P , Chupshev A V , Konovalov Vladimir V , Mishanin A L 
Published: May 2020

Abstract
The goal of the paper is on the basis of the power analysis of revealing the expressions allowing to simulate by numerical methods the power of the drive of the mixer with a spiral stirrer. Expressions of effective forces are determined as a result of force analysis of spiral blade movement in the casing filled with material segment. The calculation model implemented in the Mathcad program allows to calculate the operating forces, torque and power consumption by numerical methods. The error of calculation, taking into account the correction factor that takes into account the material spillage when changing the spiral blade pitch, relative to the experimental power data does not exceed 5%.
Studying the influence of treating potato seed tubers with hot fog of protective-stimulating preparations
Authors: Kostenko M Yu , Goryachkina I N , Rembalovich G K , Drozhzhin K N , Beznosyuk R V 
Published: May 2020

Abstract
At the moment, a new technique is often used in the technology of potato production and that is pre-treatment of seed material, which is done with the help of chemical, biological and physical methods in complex. Stimulation of plants in the initial period of the growing season requires a special approach. On the one hand, plants need nutrients and, on the other hand, they do not have a developed root system for their production. Therefore, foliar treatment of plants with protective stimulating preparations is an alternative to fertilizer application. Potassium mobilizing bacteria are able to mobilize potassium present in the soil in the root zone of plants. Liquid fertilizers based on humic acids are natural immunomodulators and stimulators of the formation, growth and development of plants, as well as antidepressants and complex nutrition additive. They are suitable for organic farming. Potato seedes were treated with hot fog of protective stimulants at temperatures from 40° C to 60° C immediately before planting. As a result of the studies, the effects of protective-stimulating preparations on plant biometry during the growing season (accumulation of aerial mass) and yield were studied. Hot fog treatment of potato seed tubers with POTASSIUM HUMATE and AZOTOVIT preparations showed the best dynamics of increasing the height of shoots of potato bushes, which exceeded the control by 5.3% and 8.2%. Pre-treatment of potato seed tubers with hot fog of protective-stimulating preparations is an effective method of increasing productivity and it contributes to better products.