bluuebunny/crossref_metadata_2025_split huggingface dataset:
General scaling laws of space charge effects in field emission
Authors: Kyritsakis A , Veske M , Djurabekova F 
Published: May 2021

Abstract
The characteristics of field electron and ion emission change when the space charge formed by the emitted charge is sufficient to suppress the extracting electric field. This phenomenon is well described for planar emitting diodes by the one dimensional (1D) theory. Here we generalize for any 3D geometry by deriving the scaling laws describing the field suppression in the weak space charge regime. We propose a novel corrected equivalent planar diode model, which describes the space charge effects for any geometry in terms of the 1D theory, utilizing a correction factor that adjusts the diode’s scaling characteristics. We then develop a computational method, based on the particle-in-cell (PIC) technique, which solves numerically the space charge problem. We validate our theory by comparing it to both our numerical calculations and existing experimental data, either of which can be used to obtain the geometrical correction factor of the corrected equivalent planar diode model.
Fractional vector-borne disease model with lifelong immunity under Caputo operator
Authors: Bulut Hasan , Ilhan Esin 
Published: May 2021

Abstract
This study provides a comprehensive analysis of the vector-borne disease model with lifelong immunity by means of the Caputo fractional differential operator. We present the existence and uniqueness of the solution of the suggested fractional disease model by utilizing the fixed-point theorem. Some basic properties of the non-integer order model such as invariant region, the positiveness of the solution are given under the Caputo derivative. Moreover, analysis of the model shows that disease-free equilibrium is locally asymptotically stable. On the other hand, numerical results with various graphs are presented by taking advantage of different values of non-integer order α. Also, for the disease model under consideration, more detailed results are obtained thanks to the fractional-order derivative as can be seen from the solution curves in the graphs.
Coherent control of magneto-optical Faraday rotation at terahertz frequencies in graphene-based metasurfaces via electromagnetically induced transparency
Authors: Ali Hazrat , Imtiaz Khan M , Ud Din Rafi , Zubair Muhammad , Mahmood Irfan , Ahmad Pervaiz , Ge Guo-Qin 
Published: May 2021

Abstract
We investigate theoretically the controlled magneto-optical Faraday rotation (MO-FR) through graphene-based metasurfaces placed on electromagnetically induced transparency (EIT) substrate at terahertz (THz) frequencies. MO-FR and transmission of the probe light are studied by changing the electric field that manipulates the group index of the substrate. The MO-FR can be controlled and enhanced by varying the periodic width of graphene ribbons. The polarization plane of MO-FR changes with 180 degrees while increasing the probe field detuning through the EIT substrate. The zero-crossing of MO-FR shifts to higher THz frequencies with increasing the magnetic field. The transmission of the probe light pulse at THz frequencies is investigated with the probe detuning and the applied magnetic field.
Improved SIFT algorithm based on image filtering
Authors: Qiao Mingyu , Liang Xiao , Chen Minjie 
Published: May 2021

Abstract
In this paper, SIFT feature extraction algorithm was optimized through image filtering, so as to highlight the role of stable edge corner and improve the efficiency of stable edge corner collection. Afterwards, the experimental results were compared and verified by the FLANN feature matching method. Experimental results show that the improved SIFT feature extraction algorithm using image filtering can improve the extraction effect of feature points with stable edge response, while suppressing the extraction of feature points with unstable edge response, thus improving the accuracy of matching.
Survey of Visual Crowdsensing
Authors: Zhai Shuying , Li Ru 
Published: May 2021

Abstract
In recent years, Visual Crowdsensing (VCS) that sensed through images and video, has become a predominant sensing paradigm of Mobile Crowdsensing (MCS), which is one of the current research hotspots. VCS requires people to capture the details of sensing objects in the real world in the form of pictures or video, which is widely used in various fields. However, there is no article summarizing the development and current situation of VCS. To this end, this paper summarized the latest applications of VCS, including floor plan generation, indoor scene reconstruction, outdoor scene reconstruction, event reconstruction, indoor localization, indoor navigation and disaster relief, and summarized some unique problems of VCS at present.
The change of node importance and influencing factors in China’s high-speed rail network
Authors: liang Xuedong , Liu Rui , Lin Shifeng , Yang Lufan 
Published: May 2021

Abstract
High-speed railway can change the geographical location of cities and enhance the importance of cities. This paper based on the complex network theory, combined with data of 2015-2019 year China’s high-speed railway lines, constructs city as the node of the high-speed railway (HSR) network model, and probed the cities of PageRank in network, examined the high-speed rail network in the change of city node importance, analysed city node importance with time evolution and the regression model was used to determine the high-speed rail network in the city the affecting factor on the changes of node importance. The results show that: (1) Many cities in western China, such as Chengdu, Chongqing, have become significantly more important, while that of eastern coastal cities remains stable or even declines. (2)The level of economic development and population have the most obvious and positive influence on the importance of urban nodes. However, geographical location (latitude) and coastal area have negative effects on node importance.
Computer vision for system protection of elevators
Authors: Lan Shengnan , Gao Yipeng , Jiang Saihua 
Published: May 2021

Abstract
With rapid development of computer vision (CV), traditional elevator control and protection technology have begun to integrate with CV technology in order to improve safety of elevators. By introducing CV technology, the real-time state monitoring of elevator components is realized, the elevator door control system based on CV is proposed, and the abnormal behavior of passengers in the elevator car is identified and alarmed. Based on summarizing the basic principles of CV technology, this paper summarized the application of CV technology in elevator safety from two aspects: equipment safety and passenger safety. Finally, the future trends of CV-based system protection of elevators are discussed.
Landslide monitoring system based on fiber optic sensor and CCD TSL1401CL linear sensor array
Authors: Costrada Aldo Novaznursyah , Harmadi  , Kemal Badrul Mustafa , Marzuki  
Published: May 2021

AbstractA landslide monitoring system using fiber optic sensor and CCD TSL140CL linear sensor array has been designed. Fiber optic sensor was designed to sense the displacement of lanslide and CCD TSL1401CL linear sensor array was used to measure the rain intensity. The data of landslide and rain intensity send using GSM SIM 900A module to personal computer which paired with GSM Wavecom modem as a receiver. The result of the testing derived that fiber optic sensor which has been designed can monitor the displacement with 0,59 % of error percentage. Monitoring system of landslide can display rain intensity, displacement of landslide, and condition of landslide in real time to PC as early warning.
Flood monitoring system using ultrasonic sensor SN-SR04T and SIM 900A
Authors: Dswilan Sixtinah , Harmadi  , Marzuki  
Published: May 2021

Abstract
A flood monitoring system using ultrasonic sensors JSN-SR04T and SIM 900A have been designed. The system consists of solar panels as a source of electrical energy, JSN-SR04T as a water level detector and SIM 900A as a sent of flood information. The test results prove that the JSN-SR04T has been able to detect 20 cm to 600 cm of distances. The results of the water level produced were 5.0314 mV/cm of sensitivity and 0,.9996 of regression value. The sensitivity states that for every 1 cm of water level there was a change 5.0314 mV of voltage and a regression value close to 1 cm indicated that the sensor was worked properly. The test results also prove that used a buoy produced a smaller of error percentage than not used a buoy, but the measurement not used a buoy can minimize errors when tested in the field. Measurement error caused by increased water discharge when it rains which can affect the buoy send a signal to JSN SR04T. The tested overall has been able to detect water levels, water level conditions and sent information, so that it is beneficial for the community to flood monitor the river flow.
Preliminary study of graphene like material fabrication from coconut shell using conventional furnace
Authors: Hidayat Rahmat , Jhora Fadhila Ulfa , Pangestuti Annisa Dewi 
Published: May 2021

AbstractGraphene has risen into a very interesting material because of its extraordinary properties. A new breakthrough that challenges the researcher is how to synthesis graphene from biomass as natural waste and plentiful resources. Coconut shell attracts the most attention because it contains the highest carbon atom among others. In this work, we present the experiment using conventional furnace to overcome the expensive one. Unfortunately, the result is not as expected that Fe2O3is formed instead of amorphous carbon. We are trying to describe what caused this happen and recommendation to overcome this problem.
Magnetic morphology and mineralogy in urban soil of Bandung City, Indonesia
Authors: Kirana K H , Apriliawardani J , Ariza D , Fitriani D , Agustine E , Nugraha M G 
Published: May 2021

Abstract
High numbers of vehicles and its activity in Bandung City resulting in levels of pollution caused by their particulates on the top soils. Since the urban topsoil containing particulates are harmful, thus its mineralogy and morphology need to identified. The samples of topsoil were taken in several locations around Bandung City. Afterwards, the topsoil samples were extracted for mineralogy and morphology analysis using X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) tests. The result of XRD measurement shows that the magnetic mineral dominated by magnetite. The magnetite is iron rich mineral that could be changed in morphology by the oxidation during environmental changing. Furthermore, the morphology of the magnetic mineral by SEM analysis exhibit the shapes of octahedron and spherules. The octahedron shape represents of paedogenic magnetic mineral carrier while the spherule indicate the presence of anthropogenic mineral. EDX analysis show the evidence of heavy metal elements on the magnetic mineral with spherule shape that caused by vehicles particulates.
Effect of zeolite catalyst concentration on bio-fuel characteristics of corncobs (Zea mays l.) produced by pyro-catalytic method
Authors: Jahiding M , Usman I , Isra  , Rizki R S , Mashuni  
Published: May 2021

Abstract
One alternative energy source that can be renewed is the conversion of biomass into bio-fuel. This study aims to produce bio-fuel from corn cobs and determine effect of catalyst concentration on physical and chemical properties. The pyro-catalytic process was carried out at 400? with 5%, 6% and 7% catalyst variations. Bio-fuel physical ssscharacterization tests include density, viscosity, and calorific value, while the analysis of hydrocarbon compound content uses GC-MS instrumentation. The results showed optimum biofuel volume was obtained at 7% catalyst variation that is 232 ml, while for physical and chemical characteristics the best results were obtained at 6% catalyst percentage with a density of 0.9636 gr/ml, viscosity 28.59 cP, and the calorific value is 10,350 kcal/kg. GC-MS analysis showed the content of Phenol, Furfural, acetic acid, Benzene, and Toluene compounds with a fuel percentage of 56.13% on a 6% catalyst. Based on the overall analysis that has been done shows that bio-fuel can be used as a substitute material for diesel or alternative energy substitute for conventional fuel.
Performance column adsorption of methylene blue using composite spent coffe ground-copper ferrites (SCG/CuFe2O4)
Authors: Erdawati  , Nanda Elsa Vera , Pratiwi Yussi 
Published: May 2021

Abstract
Composite Spent Coffe Ground-Copper Ferrites (SCG/CuFe2O4) synthesized by the method of precipitation. Copper nitrate, Ferri nitrate, SCG and sodium hydroxide mixed and stirred at 80°C for 5h, then calcined at 600°C for 2 h. The purpose of this research is to determine capacity adsorption SCG/CuFe2O4 to adsorb Methylen Blue (MB) with a column system. Approximately 0.5 g of SCG/CuFe2O4 were packed in to the column. Infusion tube filled with 250 mL MB 20 mg.L-1 was adjusted to pH 10, streamed into the column with flow rate 0.8 mL/min and 1.2 mL/min. The results obtained show that the faster the flow rate, the adsorption capacity (q0) and Thomas constant (kTh) MB increase. The highest q0 and kTh values were obtained at a flow rate of 0.8 L/min at 80.13 mg/g, 0.0028 L/mg. min.Desorption of CuFe2O4 with 0.1 M HCl solution show with 3 times elution, all MB bound to the adsorbent can be removed.
Time correction to eliminate structural ambiguity on velocity anomaly in the upper cibulakan formation of ITEUNG field, northern West Java basin
Authors: Tsany A , Indriani R F , Mariyanto M 
Published: May 2021

Abstract
Converting seismic data or structural maps from time to depth domain is very important in the stage of oil and gas exploration. Interpretation in time domain often produce inaccurate interpretation especially in zones under high velocity such as sub-salt or sub-carbonate. Under this zone, there are pull up velocity anomalies or pseudo-anticline. Otherwise in zones under low velocity such as water bottoms with sharp or fluctuating slopes (canyons), loose material overburden or rapid sedimentation, under detached electric normal faults and shale flaps, there are push down velocity anomaly or pseudo-syncline. The study area is in the Main and Massive Formation of ITEUNG Field, Northern West Java Basin where is proven to have petroleum potential. In the study area there are pull-up velocity anomaly or pseudo-anticline even though in reality they are just flat or even syncline due to the location in the zone under high velocity. This study aims to correct velocity anomaly by doing time correction and convert the time domain structure map into depth domain structure map with the time-depth curve method to eliminate structural ambiguity on velocity anomaly. The result shows that the map is obtained in the form of a depth domain structure map which is more accurate than the time domain structure map. Depth structure map make the interpretation more accurate because the structures in depth structure map is more similar to the original sovereignty after correlating with well data. In this present study shows that pull up velocity anomaly can be avoided so that interpretation can be done more accurately.
Nonlinear dynamics of modified peyrard-bishop DNA model in nosé-hoover thermostat
Authors: Sutantyo Trengginas E P , Ripai A , Abdullah Z , Hidayat W 
Published: May 2021

Abstract
In this study, we investigate the viscous effect by adding solvent potential into Hamiltonian Peyrard-Bishop DNA model. The dynamics of the modified Peyrard-Bishop DNA model is also considered in time-dependent thermal friction, namely Nose-Hoover Thermostat. Equation of motion formulate by using an analytical method, then solved using a numerical method. We show the pattern of phase space diagrams of the DNA dynamics in each variation of viscous and temperature, the movement of base pairs at a specific temperature, and the thermostat’s energy fluctuation that affects DNA dynamics.
Validity of physics student e-book based on the STEM approach to improve knowledge competence
Authors: Pratiwi Y , Yulia S R , Ramli R 
Published: May 2021

Abstract
Achieving the competency of students’ knowledge in learning Physics is still not optimal. This is due to the lack of available teaching materials that fit the needs of students, teaching materials available are only in the form of printed teaching materials and there is no approach in them, and learning has not been entirely centered on students who demonstrate lack of independence in learning. Utilization of technology is one of the efforts to facilitate learning in accordance with the needs of students by developing non-printed teaching materials in the form of a student ebook based on the STEM approach. The purpose of this study was to produce a student ebook based on a valid STEM approach. This type of research is research and development using the ADDIE model. The method used in this research is descriptive statistics. Student ebook validity was assessed by four experts using a validity questionnaire. The validity of the student ebook was analyzed using the formula Aiken’s V. The results of the validation showed that the aspect of the validity of the material substance was 0.89; visual display 0.92; and learning design 0.88. Based on the data analysis that has been done, student ebooks get an average value of 0.90 in the valid category. Thus, the student ebook based on the STEM approach can be implemented in physics learning to improve students’ knowledge competence.
Analysis of the competency standard of its graduates for the developing of physics e-book with tsunami theme
Authors: Firaina R , Fauzi A 
Published: May 2021

Abstract
Tsunami threat preparedness is important to reduce the risk of disaster. Tsunami disasters can be used as themes in physics learning to support disaster mitigation education integrated into teaching materials in the form of e-books. Tsunami disaster mitigation efforts are closely related to student competencies, so it is important to do preliminary analysis. The purpose of this study is to analyze the competency standard of its graduates as a qualification criteria for the students’ ability that is expected to be achieved. This study uses a quantitative descriptive method with the population being all high schools in Pesisir Selatan and the sample selected using a purposive sampling technique. The instrument used was a questionnaire that included several questions on aspects of attitude, knowledge, and skills. The results showed that the attitudes and skills competency were in less category with values of 75% and 72.44% respectively. The knowledge competency is in very less category with a value of 56.86%. These results indicate that the three competencies need to be further improved, especially the knowledge competency with the lowest percentage value.
Analysis of the competency standard of its graduates for the developing of physics e-book with earthquake theme
Authors: Khair N , Fauzi A 
Published: May 2021

Abstract
The earthquake is one of the disasters that occur in Indonesia. Knowledge about earthquake disasters can be integrated into physics through an e-book with the theme of earthquake disasters. One of the initial analyzes in e-book development is the analysis of graduate competency standards, which is one of the criteria to see student abilities in terms of attitudes, knowledge and skills competencies. The purpose of this study was to analyze the standards of graduates in the development of high school physics e-book on the theme of earth disasters. This type of research is a descriptive study with a population of all SMA in the city of Padang. The research instrument was in the form of a questionnaire sheet filled out by educators. The conclusions obtained from this study are the standard analysis of graduates that has been carried out with a competency value of student attitudes of 74.44%, knowledge competence of 56.37% and competency of skills of 67.95%. The results of this analysis can be used as a guide in developing an e-book on earthquake physics. The results of this analysis can serve as a guide in developing an e-book on physics on the theme of earthquake disasters.
Preliminary study of development of physics e-module using smartphone-assisted inquiry based learning models to support 21st century learning
Authors: Risma M , Yulkifli  
Published: May 2021

Abstract
The 21st century requires use of technology in learning. One technological device is smartphone. Smartphone-assisted learning materials are expected to increase the independence and competence of students. In addition, the learning model used must also be adapted to the curriculum and characteristics of the subjects. Facts at school show that learning hasn’t fully utilized technology. The learning material used is still in printed form and hasn’t been integrated with the learning model. This causes the student’s competency achievement to be less than optimal. Starting from the explanation, it takes learning materials in the form of e-modules using the Inquiry Based Learning model assisted by smartphones to facilitate students learning wherever and whenever. The purpose of this study was to analyze the development of the Physics e-module using a smartphone-assisted Inquiry Based Learning model for class X. The analysis conducted in this study was in the form of an analysis of needs, student characteristics, learning materials, and task analysis. The instrument used was a questionnaire sheet. The research method used was a quantitative descriptive study with the study sample were students of SMAN 3 Padang, SMA Pembangunan Laboratorium UNP and SMAN 12 Padang. The results of this study are descriptive data.
Conditions of learning physics and students’ understanding of the concept of motion during the covid-19 pandemic
Authors: Puspitasari R , Mufit F , Asrizal  
Published: May 2021

Abstract
An urgent learning problem in the Covid 19 pandemic is the unavailability of IT-based teaching materials that support online learning. In addition, in learning physics there are also fundamental problems, namely students’ low understanding of concepts. Misconceptions often occur in learning physics, especially in the concept of motion. Therefore it is necessary to know the problems and supporting factors of learning, especially in motion material, so that the right solution can be found. This study aims to determine students’ understanding of the concept of motion and to determine the conditions of learning in one of the high schools in Padang Pariaman Indonesia. This type of research is descriptive research, in the form of survey research. The instrument used was a concept test of motion taken from the FCI (Force Concept Inventory), this test is equipped with questions of belief and answers to the students’ reasons. Another instrument is a student and teacher questionnaire. The sample consisted of 31 superior class students and 3 physics teachers. The results showed that 36% of students had misconceptions, 34% of students did not understand the concept and only 30% of students understood the concept even though they had studied the topic being tested. Teacher learning is also lacking in identifying misconceptions (50%), less experimental activities (50%), discussions (58%) and other activities that actively involve students. Meanwhile students want learning that involves them actively even in the conditions of online learning during the current Covid19 era.