bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of the regularization method to some singularly perturbed hyperbolic partial differential equations
Authors: Zakharova I V 
Published: April 2021

Abstract
This paper considers the Cauchy problem for a hyperbolic partial differential equation containing a small parameter in the main part. When the small parameter is zero, the order of the equation does not decrease, but the original problem changes its type and becomes a Cauchy problem for a parabolic equation. The inability of a solution to the limit problem to satisfy all the conditions of the original problem leads to creation of a boundary layer region in the neighborhood of the initial conditions. The structure of an asymptotic solution to a singularly perturbed problem in the form of a regularized series makes it possible to write the solution as a single whole, without separately constructing boundary functions. In this case, the boundary effects are described by additional independent variables introduced by the spectrum of the limit operator. The principal feature of the problem considered in this paper, namely, absence of the spectrum of the limit operator, does not allow us to fully apply the method of constructing an asymptotic solution by the regularization method of S. A. Lomov. In this paper, we propose a method for solving such problems using the direct Fourier transform. An algorithm for formulating the coefficients of a regularized series is given, and zero and first terms of the asymptotic are formulated.
On the solvability of a semilinear hyperbolic equation with a parameter
Authors: Kerimbekov A , Baetov A , Krasnichenko L 
Published: April 2021

Abstract
A semilinear hyperbolic equation with a parameter is considered. Sufficient conditions for unambiguous solvability of the boundary value problem are proved. A range of parameter values is specified for which a boundary value problem has a unique solution.
Mathematical modelling of biology processes based on the table of prime links in the solid torus up to 4 crossings
Authors: Akimova A A 
Published: April 2021

Abstract
The motivation to study links in lens spaces can be justified in recent applications to theoretical physics and biology. In this paper, we give a short outline of practical significance and implementation proposals of such links, the study of which begins with the study of links in the solid torus, since a punctured disk diagram of a link in the lens space can be considered as a punctured disk diagram in the solid torus provided with the additional slide move. However, links in the solid torus find their applications themselves as well. In this paper, we propose a method to represent knotted proteins as links in the solid torus. Such a method is based on the existence of correspondence between knotoids and knots in the solid torus using a double branched cover. To this end, the table of links in solid torus is necessary. Therefore, we classify all prime links in the solid torus up to 4 crossings. One of possible future applications of the constructed table is an analysis of the database LinkProt that collects information about protein chains and complexes that form links. Also, our table can be used to construct table of prime links in lens spaces.
Genetic algorithm for minimization of ESOP representations for multiple-output logic functions
Authors: Kazimirov A , Maleyev V 
Published: April 2021

Abstract
This article concerns ESOP representations for multiple-output logic functions. Exclusive-or sum-of-products expression (ESOP) is a formula representing a logic function as an exclusive-or sum of products of variables and their negations. EXOR-based realization leads to reduction in size of logic circuits for many practical logic functions and improves their testability. Minimization of a logic function is a problem of constructing ESOP representation for the given function having the minimal number of summands. We introduce a correspondence between ESOPs for multiple-output logic functions and single-output logic functions and propose genetic algorithm obtaining close to minimal ESOP representations for multiple-output logic functions.
Program complex for solving of some classes of aerohydroelasticity problems
Authors: Ankilov A V , Velmisov P A 
Published: April 2021

Abstract
On the basis of the developed mathematical models, a program complex was created for studying the dynamics and stability of an elastic pipeline, an elastic structural element in supersonic flow, elastic elements of wing profiles of several types with subsonic flow, elastic elements of vibration devices of several types. The complex generates three-dimensional graphs of element deformations, construction of animation graphs of element deformations, construction of flat graphs of deformations and strain rate at a given point or at a given time. On the basis of the constructed graphs, one can study the dynamics and draw conclusions about the stability of vibrations of elastic structural elements.
Limit transitions in plane homogenization problems for two-phase dielectric composites with extreme material properties of one phase
Authors: Kudimova A B , Nasedkin A V 
Published: April 2021

Abstract
The plane problem of calculating the effective dielectric constant of two-phase composite consisting of main material with one circular inclusion is considered. To solve the homogenization problem, the method of effective moduli with the support of the energy balance between the composite and the homogeneous comparison medium was used. In the solution obtained, the passage to the limit was made for the case of an inclusion with zero dielectric constant and for the case of a conductive inclusion. The limiting solutions are compared with the solutions of homogenization problems for a medium with a hollow and for a medium with a conducting inclusion boundary.
Micromagnetic modeling of the polycrystalline structure effect to the hysteresis loop in ferromagnetic nanowire
Authors: Satsuk S A , Komogortsev S V 
Published: April 2021

Abstract
Extensive micromagnetic simulation results of the hysteresis loops in ferromagnetic nanowire with randomly oriented crystallites ordered in one chain is presented. Three main contributions to the magnetic energy of the wire had been taken into account: exchange, dipole-dipole, and the magnetic anisotropy energy of the crystallite. In cases where one of the three contributions to the energy can be neglected, the numerical calculations are in good agreement with the results of the well-known, analytically studied micromagnetic problems. In the case when all three contributions are comparable, a complex non-monotonic dependence of the coercive force on the crystallite size and the magnetic anisotropy constant is observed. In order to interpret these changes, a new micromagnetic scale is introduced, which takes into account all three contributions to the magnetic energy of the wire, and performs a correct transition to the analytically studied limits, which take into account the competition of any two contributions.
A complex absorbing potential electron propagator approach to resonance states of metastable anions
Authors: Belogolova A M , Dempwolff A L , Dreuw A , Trofimov A B 
Published: April 2021

Abstract
An earlier developed electron propagator method for the treatment of electron attachment to molecules within the non-Dyson algebraic-diagrammatic construction framework (EA-ADC) is extended by inclusion of the complex absorbing potential (CAP). The resulting method allows for the investigation of resonance states of metastable anions. Approximation schemes up to third-order perturbation theory for the electron propagator (EA-ADC(3)) are implemented. The CAP operator is treated up to second-order using the intermediate state representation formalism (ISR(2)) and the subspace projection technique. The CAP/EA-ADC(3) method is tested in first applications to the resonances in CO and N2 molecules associated with electron attachment to their low-lying π*-orbitals. The results of the calculations agree well with the available experimental and theoretical data and demonstrate the CAP-augmented EA-ADC modeling can become a useful tool for theoretical studies of metastable electron-attached states.
Vibronic coupling in the Pyridine Radical Cation: Nuclear Dynamics Studied Using the Multi-configuration Time-Dependent Hartree method
Authors: Grigoricheva E K , Skitnevskaya A D , Gromov E V , Trofimov A B 
Published: April 2021

Abstract
The multi-configuration time-dependent Hartree (MCTDH) method was applied to study nuclear dynamics following transitions to a manifold of vibronically coupled ground 2A1 and excited 2A2 and 2B1 states of the pyridine radical cation (PRC). These states originate from ionization out of the highest occupied orbitals of pyridine, 7a1 (nσ), 1a2 (π), and 2b1 (π), respectively, and give rise to the lowest two photoelectron bands. We focus on various theoretical and computational aspects of the MCTDH method and methodology to calculate the spectrum, taking our study of the vibronically interacting 2A1, 2A2, and 2B1 states of PRC as an example. In particular, the choice of the single-particle functions (SPFs) and schemes to combine vibrational modes are discussed.
Inhibitory effect of tannin extract from Acacia bark (Acacia mangium Willd.) against gastro-intestinal pathogenic bacteria
Authors: Sinaga D M , Laconi E B , Jayanegara A 
Published: April 2021

Abstract
Acacia (Acacia mangium Willd) is a fast growing tree species that widely found in Indonesia. Acacia bark contains a number of secondary metabolites such as tannin, saponin and flavonoid that may inhibit the growth of undesirable microbes incuding the pathogenic ones. The purpose of this research was to evaluate the antimicrobial activity of tannin extract obtained from Acacia bark against common pathogenic bacteria species present in the gastro-intestinal tract of livestock, i.e., Salmonella typhimurium and Eschericia coli as Gram negative bacteria. The disc diffusion method was employed for assessing the antimicrobial activity of Acacia tannin extract. Treatments consisted of negative control (NC), positive control by using chloramphenicol (PC), Acacia tannin extract at two concentrations, i.e., 1% (AT1) and 2% w/v (AT2), and commercial chestnut tannin at 1% (CT1) and 2% w/v (CT2). Data were analyzed by using analysis of variance and followed by a post-hoc test namely Duncan’s multiple range test. Results showed that the inhibitory diameters formed on the activity assay of AT in the form powder, liquid and CT with concentration of 2% against Salmonella typhimurium bacteria were 17.3, 7 and 16 mm, respectively. Inhibitory diameters of AT powder, AT liquid and CT against Eschericia coli bacteria were 17.3, 0 and 17 mm, respectively. The AT powder resulted in a higher inhibition of both pathogenic bacteria species than that of liquid form (P<0.05), whereas its inhibitory effect was similar to commercial CT. In conclusion, 2% AT can be used to inhibit the growth of Salmonella typhimurium and Eschericia coli bacteria in which its magnitude of inhibition is comparable with commercial tannin extract from chestnut.
Technology development in thermochemistry materials
Authors: Wibawa B , Syakdiyah H , Kardipah S 
Published: April 2021

Abstract
Thermochemistry is an important basic concept in studying advanced chemistry. Thermochemistry is very important to understand correctly and easily. This research aims to develop technology that can facilitate understanding of thermochemistry. This research is a research and development research (R & D). In this research, a technological development can be produced which can be used to facilitate understanding of thermochemical concepts. This research resulted in a framework of thermochemical material integrated with science (biology, physics), mathematics, engineering, ICT technology.
Purification of Fim-C-Salmonella typhi recombinant protein with Ni-NTA resin as raw material for typhoid disease detection kit
Authors: Nurjayadi M , Setiyoto T , Jinan S F , Hardianto D , Sulfianti A , Agustini K , El-Enshasy H A 
Published: April 2021

Abstract
Typhoid fever caused by Salmonella typhi is an endemic disease in Asia, including Indonesia. Based on data from the World Health Organization (WHO), there are 81% per 100,000 people in Indonesia infected with typhoid. Based on this, development of typhoid detection kit that is simple, fast, specific and sensitive is still needed. One of the developments of detection kits currently available is the antigen and antibody interaction approach. This study aims to obtain comprehensive information about purification of recombinant Fim-C-S. typhi proteins as antigens for raw materials for manufacturing typhoid detection kits. This study uses the IMAC method with Ni2+ metal, which has advantages in high selectivity and purity. The results of this study report that purification of recombinant Fim-C-S. typhi protein inclusion bodies with variations in the binding and washing process at 3, 5, and 7 times gave percent yields correspondingly of 37.84, 39.44, and 38.21% pure protein. Previous studies have also reported variations in binding and washing at 2, 4, and 6 times and gave percent yields respectively were 35.37, 39.11, and 40.49%. Based on the data, we concluded that the variation of 6 times is the best repetition variation to get the largest percent yield so that it can be used as a reference in large-scale purification.
Antioxidant activity of Litsea petiolata Hk. f
Authors: Ambarwati N S S , Elya B , Mahayasih P G M W , Awang M S N , Omar H 
Published: April 2021

Abstract

Litsea petiolata Hk. f was included Lauraceae family, and the previous study had been isolated 5 compounds from the Litsea petiolata Hk. f stem bark dichloromethane extract namely harman or aribine, norharman, reticuline, isoboldine, and thalifoline. Antioxidants can prevent tissue damage by free radical. Free radical production continuously in all cells as cellular function usually, but excess production can cause many diseases. The research aimed to assay the activity of antioxidant from the extract and fractions of the Litsea petiolata Hk. f stem bark with DPPH assay and FRAP assay. The extract was obtained by soxhletation used dichloromethane as solvent. The fractions fractionated with column chromatography. The antioxidant test used DPPH assay and FRAP assay. The IC50 values for the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test of the dichloromethane extract was 27.36 µg/mL, the fraction A was 113.74 µg/mL, fraction B was 60.17 µg/mL, and the control positive (quercetin) was 3.96 µg/ml. The EC50 values for ferric ion reducing antioxidant potential (FRAP) test of the dichloromethane extract was obtained 13.47 µg/mL, the fraction A was 76.49 µg/mL, fraction B was 55.73 µg/mL, and the control positive (quercetin) was 14.01 µg/ml. The extract had higher antioxidant activity than the fractions, and by FRAP test the extract showed better antioxidant activity than the positive control (quercetin).
MDLC model for developing multimedia e-learning on energy concept for primary school students
Authors: Kumala F N , Ghufron A , Astuti P P , Crismonika M , Hudha M N , Nita C I R 
Published: April 2021

Abstract
This study aims at developing multimedia instructional material at the elementary school level by using the MDLC (Multimedia Development Life Cycle) model. This research developed multimedia platform which consisted of learning modules and videos. MDLC constitutes methods consisting of concept, design, collection of materials, assembly, testing, and distribution. In developing multimedia by using MDLC, it was based on a flowchart system and a learning video story board. The results indicated that the multimedia developed was in accordance with the MDLC steps. Based on the results of alpha and beta tests, it indicated that the e-learning multimedia developed is feasible and practical to be used by elementary school students. Multimedia that was developed employs a variety of learning sources that are able to enrich student’s knowledge in a more interactive presentation.
A review of data mining methods in RFM-based customer segmentation
Authors: Ernawati E , Baharin S S K , Kasmin F 
Published: April 2021

Abstract
Data mining (DM) is the process of extracting knowledge from data. Knowledge from customer behaviour segmentation is useful for companies in setting the target market and developing a marketing strategy. Recency Frequency Monetary (RFM) model is the most behaviour segmentation used. Many customer-segmentation studies in various application areas use the RFM model that collaborates with DM. With many methods in DM, the selection of appropriate methods can reveal useful hidden patterns in customer segments. This paper aims to analyse DM methods that collaborate with the RFM model and synthesize them to propose a customer segmentation framework. This study uses a comprehensive literature review published in 2015-2020. The most widely used methods are clustering and visualization from seven DM methods analysed. Due to the increased visualization function and the need for customers’ geo-demographic data to be considered in the analysis, this study presents a new framework for using DM methods with the RFM based segmentation in the Geographic Information Systems (GIS) environment. This framework helps analysts utilize DM methods to uncover and understand customer characteristics, so companies can set the target market and develop a marketing strategy to increase their competitive advantage.
Utilization of data mining for placement of books in the library using the Apriori method
Authors: Waliyansyah R R , Novita M , Saputro N D 
Published: April 2021

Abstract
The Apriori Algorithm is an algorithm that is well known for performing frequent itemset searches using the association rule technique. The Apriori algorithm uses knowledge about the previously known frequent itemset to process data related to borrowing books in the library to be processed into useful information. This study uses a priori algorithm method for grouping books at the PGRI University Library in Semarang based on trends that appear together in a library activity visit. By gaining knowledge from this algorithm, it can be used as a reference for the PGRI University Library in Semarang in placing book collections.
The ability of nitrogen atomic absorption in the formation of iron nitride on flake structure and nodule in cast iron
Authors: Sujana W , Widi K A , Rahardjo T , Prihatmi T N 
Published: April 2021

Abstract
The nitriding process can be effectively applied to steel with alloying elements. The higher the alloying element in the steel maximizes the mechanical properties, including hardness. However, the raw material can be costly, therefore using cheap materials (without alloys) is a challenge in increasing surface hardness through iron nitride formation. Furthermore Grey and nodular cast iron have different properties and characteristics in the structure. This research focuses on the ability of the cast-iron structure to affect the nitride layer formation. Gas nitriding was conducted in a fluidized bed reactor with a 550°C in 20 % N2 and 80 % NH3 atmosphere at a flow rate gasses of 0.7 m3/hr process temperature and holding for 2, 4, and 6 hours. Tests are conducted by observing the depth of hardening, SEM, and EDAX. According to the results, the nitriding process increases the surface hardness of cast iron. The highest hardness value is nodular cast iron with a holding time of 6 hours (345 HV) and a hardening depth of up to 20-micron meters. The compounds formed in the nitride layer include FeN, Fe2-3N, Fe4N, and Fe2N. The compound formed is strongly influenced by the treatment time. Furthermore, the comparison of nitriding treatment on gray and nodular cast iron was influenced by the flake and nodule structure. In general, the nodule structure is responsible for maximum hardness. The longer treatment time allows the nitrogen atoms to diffuse more to the surface, while the flake structure limits the absorption of nitrogen atoms into the surface of the cast iron. Characterization of Nodular Cast Iron shows that The hardening depth distribution trend due to the nitriding process in nodular cast iron was not much different from gray cast iron.
Concentration of sheep urine solution as watering media and organic fertilizer to production of corn fodder (Zea mays) by Hydroponic system
Authors: Kustyorini T I W , Krisnaningsih A T N , Pratama R P 
Published: April 2021

Abstract
The purpose of this study was to determine the concentration of urine solution as a watering medium and organic fertilizer on the productivity of hydroponic corn fodder. The research materials were corn, sheep urine, and water, while the method used was field experiments. The treatments, namely T0 (0% urine), T1 (5% urine), T2, (10% urine), T3 (15% urine), T4 (20% urine). The variables were the percentage of germination, percentage of normal sprouts, number of leaves, plant height, fresh production and dry matter production. The data obtained were analyzed using analysis of variance, if there is an effect, then continue with the LSD test. The results showed that the treatments had a very significant effect (P <0.01) on the percentage of germination, percentage of normal germination, number of leaves, plant height, fresh production, and dry matter production. The highest germination percentage was found in T1 (91.60%), normal germination percentage T1 (86.78%), number of leaves T1 (3.0), plant height T0 (31.6 cm), forage production T1 (646.6 grams), dry matter production T1 (568.41 grams). Based on the results, it was concluded that watering with 5% concentration of sheep urine solution gave the best value for the productivity of hydroponic corn fodder.
Improvement of student mathematics learning outcomes through Kahoot learning games application at elementary school
Authors: Umboh D , Tarusu D , Marini A , Sumantri M S 
Published: April 2021

Abstract
The purpose of this research is to improve the student mathematics learning outcomes through Kahoot learning games application at elementary school. This classroom action research adopted from Kemmis and Mc Taggart Model was conducted in three cycles for the fourth grade as many as 22 students at 02 Public Elementary school in Tomohon, North Sulawesi, in Indonesia. The result of this study shows there is an improvement of students learning outcomes from cycle one to cycle three reaching 64, 72, and 81 from the maximum score of 100. Percentage of teacher and student activities increased from cycle one to cycle three achieving 77, 80, and 86 %. It can be concluded that application of Kahoot learning games can improve the student mathematics learning outcomes at 02 Public Elementary school in Tomohon, North Sulawesi, in Indonesia.
Effect of the Missouri Mathematics Project model on mathematical creativity
Authors: Novalia R , Sobar H , Ismaya R , Marini A , Sumantri M S 
Published: April 2021

Abstract
The ability of creativity needs to be the focus in learning mathematics because achievements in learning mathematics develop students’ mathematical creativity abilities. The purpose of this study is to determine the effect of the Missouri Mathematics Project model on students’ mathematical creativity abilities. The research method used is an experimental method using purposive sampling techniques with instruments that use tests and questionnaires. The results of research on student responses in the Missouri Mathematics Project model obtained 87.72% who responded positively, with the value of students’ mathematical creativity ability obtained 81.30 so that it can be said to be good. The research hypothesis test results obtained tcount> ttable (7.14> 2.02) that is the results can be accepted. The conclusion is that there is a positive influence on the Missouri Mathematics Project model with students’ mathematical creativity abilities.