bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pachystachys coccinea (Cardinal's guard).
Authors: Rojas-Sandoval Julissa 
Published: December 2020

Abstract

Pachystachys coccinea is a perennial evergreen shrub cultivated as an ornamental and garden plant for its red flowers on flashy terminal spikes. It has escaped from cultivation and is often found naturalized in damp thickets and at forest edges. Presently, P. coccinea is only listed as invasive in Cuba and as a "common" alien species in Trinidad and Tobago.
Dual-layer graphene based tunable broadband terahertz absorber relying on the coexistence of hybridization and stacking effects
Authors: Lin Rong , He Xiaoliang , Jiang Zhilong , Liu Cheng , Wang Shouyu , Kong Yan 
Published: December 2020

Abstract
With the fast development of terahertz (THz) techniques, THz absorbers have a variety of applications. However, current designs have a series of shortcomings, such as low absorption rate and a fixed and narrow absorption bandwidth. To solve such problems, in this paper, we design a tunable broadband THz absorber, which consists of two layers of graphene structures: the top layer is arrayed with the graphene concentric hexagonal rings and the bottom layer is arrayed with regular graphene hexagon rings; therefore, both layers support hybridization and stacking effects. The coexistence of both effects achieves the absorption rate of over 90% in a broad band from 0.93 THz to 1.80 THz. Moreover, the absorption spectrum can be tuned by adjusting the graphene chemical potential, which is insensitive to both incident angle and polarization. Considering advantages such as a tunable broad absorption band, a high absorption rate and insensitive incident angle and polarization, the proposed dual-layer graphene based tunable broadband THz absorber can be a useful reference for absorber design even in other electromagnetic wavebands.
Explanatory of learning models and vocational teacher perceptions of mechanical engineering during the Covid-19 pandemic
Authors: Widarto W , Sutopo S , Nurtanto M , Cahyani P A , Honggonegoro T 
Published: December 2020

Abstract
This research aims to explore the implementation of the blended learning model and describe the teacher’s perceptions of the constraints and positive impacts of applied learning. This research method uses a descriptive quantitative approach. A total of 41 respondents of mechanical engineering vocational teachers followed the filling of the instruments. Data were collected using a questionnaire in the form of respondent data, learning models used by vocational teachers and perceptions of vocational teachers. The findings of data explanatory research that are different from the implementation of the learning carried out are: (1) online theory learning without practice tends to use the Cooperative Learning of 14.63% and Problem Based Learning of 12.20%, (2) online theory learning with online practice, tends to use the Project Based Learning of 12.20%, (3) Online theory learning with offline practice, tends to use the Project Based Learning of 14.63%, and (4) learning with offline practice tends to choose inquiry learning and Project Based Learning of 2.44%. The main constraints that serve teachers are internet access and limited network availability, the positive impact on the general is the use of ICT. An important finding in this study is that vocational teachers must be able to organize learning evenly.
Effect of attitude and motivation on turning practice
Authors: Wibowo H , Setiawan H S D , Prasetya T A , Kusnantoro M I 
Published: December 2020

Abstract
This research aims to determine the effect of attitudes of turning practice with students’ turning practices achievement, the influence of turning practice motivations with turning practice achievements, and the influence of turning practice attitudes and practice motivation on the turning performance of students of PIRI 1 Vocational High School. This research is a descriptive study with a quantitative approach. This study’s population was students of class XI and XII majoring in machining engineering at PIRI 1 Vocational High School. Data collection techniques using questionnaires and documentation. Data analysis techniques using descriptive analysis and regression analysis. Based on the research results, the attitude of practice has a positive and significant effect on turning practice with a contribution of 37%. The motivation of practice has a positive and significant effect on the achievement of turning practice with a contribution of 30%. The attitude of practice and practice motivation positively and significantly affects practice achievement with a contribution of 41%, and the regression equation Y = 46,141 + 0,365.X1 + 0,183.X2.
Evaluation of shielded metal arc welding learning in vocational high school
Authors: Munadi S , Syauqi K , Feriyanto M I , Lutfian F 
Published: December 2020

Abstract
This study aims to determine the level of planning, implementation, and assessment of learning outcomes in the XI class of shielded metal arc welding (SMAW) techniques at the state vocational high school 1 Sedayu, Bantul Regency. This type of research is a descriptive study with a survey method. Data collection using a questionnaire. The study population was 90 students of class XI state vocational high school 1 Sedayu. The sample was taken the same as the population. Data collection using a questionnaire. The data analysis technique used a quantitative descriptive analysis. Based on the data analysis results, the planning category is medium, with a mean of 29.48. The implementation is a very high category with a mean of 49.60, the assessment of learning outcomes categorized as high with a mean of 10.68. The results showed that the evaluation SMAW technical learning was in the high category. Results also showed that the level of evaluation of the SMAW technique learning on planning is in the medium category and the evaluation of the implementation of the SMAW technique learning was in the very high category.
The effect of twist drill angle and spindle speed on surface roughness in S45C steel drilling process
Authors: Saputro R D A , Sukardi T , Wibowo Y E , Hardiyanta R A P 
Published: December 2020

Abstract
The purpose of this research is to determine the effect of twist drill angle variations and spindle rotational speed on the surface roughness of S45C steel in the drilling process. The method used in this research is the experimental method. The independent variables used in this study are variations in twist drill angle (118°, 122°, 125°) and spindle rotational speed variations (1036 rpm, 1340 rpm, 1630 rpm). The dependent variable used is the result of surface roughness in S45C steel. While the control variable used is a feed rate of 0.18 mm/round. The results showed the highest surface roughness was obtained at 125° twist drill angle variation and spindle rotational speed of 1630 rpm with a roughness value of 8.590 µm, while the lowest surface roughness value was obtained at 118° twist drill angle variation and spindle rotational speed of 1036 rpm with a roughness value of 2.898 µm. This research can be developed to find standards from other aspects that affect the results of the drilling process.
Model of university-industry collaboration to support internship program in Engineering Faculty of Universitas Negeri Yogyakarta
Authors: Sudiyatno S , Nuryanto A , Sutopo S , Nashir I M 
Published: December 2020

Abstract
Collaboration between industry and universities is well recognized by scholars and policy makers as a necessity for industrial innovation products and university graduate skills development. This study presents a proposed university-industry collaboration model which expresses the university and industry benefits obtained through the collaboration experiences. Method used to explore the model of collaboration that will be proposed is observation to industries where students doing internship and FGD. The result shows that activities of collaboration are very potential to bring benefits to both parties. The proposed UIC model is suited for use at two different courses, those are internship program and final project course. The model is also implemented to assist in realizing the third role of universities in community service in the area of the contribution to innovation and R & D, production commercialization and technology transfer.
Modeling of Hydraulic ABS Plant and its Control By Using fuzzy Mamdani with adaptive slip Frequency to improve stopping distance and steering ability
Authors: Sumarli  , Harly Muchammad , Marji  
Published: December 2020

Abstract
Many antilock btrake system ABS (what is ABS?) plant dynamics were designed and developed by researcher, it is mostly in quarter car model. Plant could be ABS with hydraulic, air or electromagnetic energy transfer of braking processes. Kind of ABS controller method were also developed and proposed to achieve the desired control response such as, stopping distance and steering ability under circumstance non-linear braking dynamics and uncertainty road surface-wheel. There is no-intelligent and artificial control event hybrid of both. PID, Observer, sliding mode, LQR, Fuzzy and Neural network are commonly used to control ABS plant. This research method proposed ABS hydraulic plant design, which controlled by Fuzzy to control slip frequency within three sample of road surface namely snow, sand and asphalt surface road. For slip control reference variable are setup in varied value to approach the optimal sopping distance. Result of simulation shown that slip of 2,35 has a superior of stopping distance control, means the shortest stopping distance compared with another setting value.
Project-based learning model with real object in vocational school learning
Authors: Arifin Handoyono Nurcholish , Suparmin  , Samidjo  , Bintoro Johan Arif , Suyitno  
Published: December 2020

Abstract
Learning in vocational schools is not enough just teacher-centered because the material presented does not only cover cognitive aspects, but also the affective and psychomotor aspects. In fact, there are still many teachers who use conventional modes, including learning technical drawings, so that student learning outcomes are low. The purpose of this research was to determine the learning outcomes of the PjBL model using real object media better than conventional methods in technical drawing subjects. A quasi-experiment was used in research with a nonequivalent control group design. The study population was 42 students of class X TP. The sampling technique uses cluster sampling. Class X TP1 as a control class with 23 students and Class X TP2 as an experimental class with 19 students. Data collection techniques using test techniques. The research instrument was a test sheet. The data analysis used t-test analysis with prerequisite tests, namely the normality test and homogeneity test. Based on testing the hypothesis test, it was concluded that the PjBL model with real objects gives better learning outcomes compared to conventional methods of learning outcomes of technical drawings.
Robust parameter design of shielded metal arc welding (smaw) for optimum tensile strength
Authors: Setiawan M.D.I. , Pradana Y.R.A. , Suprayitno  
Published: December 2020

AbstractShielded Metal Arc Welding (SMAW), an arc welding process that uses a consumable electrode consisting of a filler metal rod coated with chemicals that provide flux and shielding, is widely used in engineering applications. SMAW parameters that usually applied in practice is still possible to be optimized to improve the process to become robust. This work is focus on an optimization of SMAW process on ASTM A500 Hollow Square Pipe, as it is widely found in applications. The welding parameters such as welding current, electrode angle, root gap, and electrode type are adopted as process parameters. Taguchi robust optimization is applied as optimization strategy, and L9 fractional orthogonal array is selected as design of experiment. The optimization objective is to maximize tensile strength of SMAW welded joint. The optimization results found that welding current 100A, electrode angle 90o, root gap 2 mm, and electrode type E7018 of SMAW parameters give the optimum tensile strength. The tensile strength gain of robust design based on the initial design was carried out by 98,39 MPa (from 259,45 MPa of initial design to 357,84 MPa of optimum design).
The Effect of CVT Rollers Weight on Power and Torque of Honda Vario 125 Engine in Garuda Hybrid Car 2017
Authors: Arta I W Y , Arifin Z , Yudantoko A 
Published: December 2020

Abstract
This study aims to find out the impact of CVT roller’s weight variable to “Honda Vario” 125 engine power and its torque in “Garuda Hybrid 2017 car”. This paper is a kind of experimental research. The object of this paper is the “Honda Vario” 125 engine that has been bored down to 120cc in “Garuda Hybrid 2017 car”. There are 5 different types of calibration samples. The calibration uses a dyno test to test the engine. After calibrating the engine, the research uses descriptive analysis as the analysis data technique. The results show that: (1) the change of CVT “Honda Vario” 125 weight variable roller influence the power produced by the engine; the bigger the roller weight, the bigger the power produced by the engine. (2) The influence of its weight variable also influences the torque of the engine; the lighter the roller weight, the bigger the torque of the engine.
The Effect of Tire Pressure to Fuel Consumption of G19 Garuda Urban Cars
Authors: Arifin Z , Yoga I N 
Published: December 2020

Abstract
The purpose of this study was to determine the effect of tire pressure on fuel consumption for Garuda Urban Gasoline G19 in the Shell eco-marathon Asia, 2019. This research is a type of experimental research using FDR tires on the UG19. The research was conducted by applying the tire air pressure 50 Psi, 75 Psi, 80 Psi, and 90 Psi in each pressure test, the calculation of fuel consumption is carried out to determine the effect of energy consumption in each test of each pressure. The data analysis method was carried out by using descriptive analysis. The results showed that: By applying FDR tire pressure for UG19 cars with a pressure of 90 Psi, the fuel consumption reached 5.1 ml with the calculation of the achievement of energy consumption of 395 km / l. With the test results, it shows that giving an increase in tire pressure will greatly affect fuel consumption and energy consumption achievement.
Efforts to improve chassis system learning through learning media anti-lock brake system (abs) integrated hardware-in-the-loop (hil)
Authors: Nauri I.M. , Ihwanudin M. , Ismail H. , Mindarta E.K. , Harly M. , Sumarli Putra A.B. , Awanggapati B. 
Published: December 2020

Abstract
The chassis system directs students to understand the basic concepts of modern motor vehicle maintenance and repair. One of the subjects is the anti-lock brake system (ABS) which can cause misconceptions in learners. So it takes learning media that can improve understanding and learning results,namely learning media anti-lock brake system (ABS) integrated hardware-in-the-loop (HIL). The implementation of ABS-HIL aims to improve student learning outcomes. Before application, the development of learning media is carried out. Sample of 27 students, with observation & pre-test & post-test data collection techniques. The data is analyzed descriptively and tests “t”. The results of the study found an improvement in the results of the study proven post-test scores = 90,44 more than the pre-test score = 78,44.
SU(1, 1) covariant s-parametrized maps
Authors: Klimov Andrei B , Seyfarth Ulrich , de Guise Hubert , Sánchez-Soto Luis L 
Published: December 2020

Abstract
We propose a practical recipe to compute the s-parametrized maps for systems with SU(1, 1) symmetry using a connection between the Q- and P-symbols through the action of an operator invariant under the group. This establishes equivalence relations between s-parametrized SU(1, 1)-covariant maps. The particular case of the self-dual (Wigner) phase-space functions, defined on the upper sheet of the two-sheet hyperboloid (or, equivalently, inside the Poincaré disc) are analysed.
Unsteady processes in a centrifugal compressor: from a physical experiment to a virtual stand
Authors: Lebedev A , Kozhukhov Y , Ivanov V , Kartashov S , Nguyen M H , Lebedeva S , Lopulalan Kh , Aksenov A 
Published: December 2020

Abstract
Virtual testing unit description for unsteady flow phenomena investigations in a centrifugal compressor based on ANSYS 12.0 system is presented. Comparisons of calculated and experimental results for steady and unsteady data are acceptable. Transient Blade Row methods (the CFX Transient Blade Row Modeling with the terminology of Turbo component) - is the sector of blades in a given blade row that are being modeled in the analysis. Transient Rotor-stator analyses involve at least two components, one rotating and one stationary component.
Non-stationary processes in a centrifugal compressor: from experiment to practice
Authors: Lebedev A , Lebedeva S , Kozhukhov Y , Kartashov S , Ivanov V , Yanin I , Hai N M 
Published: December 2020

Abstract
The article deals with the problems of diagnostics of surging phenomena in centrifugal compressors. The reasons for the surge phenomenon and the method for its diagnosis to prevent emergencies are stated. The article describes the phenomenon of rotating stall, which precedes the surge. Diagnostics of the appearance of a rotating stall opens the possibility of predicting the appearance of a surge. This allows for an efficient and safe surge protection system. Solving the problem of developing new principles for constructing surge diagnostics systems. Application of biorthogonal wavelet transform for prebreak detection.
Fluid - structure interaction analyze for the centrifugal compressor 3d impellers
Authors: Danilishin A , Petrov A , Kozhukhov Y , Kartashov S , Ivanov V , Zuev A 
Published: December 2020

Abstract
The article deals with the issues of the 3D impellers strength analysis for the different centrifugal compressors. Two air compressors are considered, the first for General industrial use, the second for turbocharging the internal combustion engine. The third compressor is designed for the turboexpander unit that operating at high pressure medium. The materials of the impellers were steel, titanium and aluminum alloys. The expediency of using the Fluid-Structure Interaction approach for the strength analysis is considered for these compressors. With the FSI approach, a coupled CFD-FEA solution is performed. Gas-dynamic forces from the medium pressure are taken into account in the impeller strength or vibration analysis. The Ansys package is selected as the program for analysis. CFD models are built and configured in the Ansys CFX. The FEA solution carried out in the Ansys Static structural. The results of strength analysis are compared with and without pressure forces for all impellers. As a result, there were no significant differences in the two solutions for the air compressors. However, for high-pressure compressors, the results of the coupled solution showed the need to take into account the CFD solution. Based on the obtained data, a graph of the reliability coefficient dependence on the increase in the suction pressure in the range from 1 to 100 bar is plotted.
Investigation of the elemental composition of the WNF-95 sintered powder alloy obtained by the electroerosive dispersion of waste in a carbon-containing liquid
Authors: Ageev E , Ageeva E , Khoryakova N 
Published: December 2020

Abstract
The results of the study of the pressed and sintered electroerosive powder alloy WNF -95 are presented. Powder alloy WNF-95 was obtained by electrodispersion of shavings from waste tungsten- nickel-iron alloy in kerosene. Sintering of electroerosive powder alloy WNF-95 was carried out by the method of spark plasma sintering. The aim of this work was to study the elemental composition of the WNF-95 sintered powder alloy obtained by electrodispersion of waste in kerosene. It has been established that the elemental composition of the sintered sample obtained by sintering the electroerosive pseudo-alloy WNF-95 is comparable to the elemental composition of the initial powder, which indicates the efficiency of its use for the manufacture of tungsten-nickel-iron alloys.
Increasing the efficiency of the working process of a forest fire ground-sweeping machine with an energy-saving hydraulic drive of the throwing rotor
Authors: Popikov P I , Gnusov M A , Popikov V P , Sharov A V 
Published: December 2020

Abstract
The article deals with the problem of creating machines and units for the prevention and suppression of forest ground fire. The purpose of the study is to increase the efficiency of the working process of the soil-throwing machine by substantiating the parameters of the energy-saving hydraulic drive of the rotor-thrower. The rational values of the pre-charging pressure and the working volume of the pneumohydraulic accumulator have been established, which ensure the reduction to a minimum of the number of operation of the safety valves when the rotor-thrower meets obstacles. The optimum charging pressure of the pneumohydraulic accumulator is 6 … 7 MPa, the working volume is 5 … 8 dm3, while the energy-saving hydraulic drive stores energy of about 15 … 17 kJ during the working cycle, pressure surges do not exceed 13.3 MPa, and the recovered energy at density of obstacles up to 200 pcs / km due to the reduction in the number of operation of safety valves can be about 3000 kJ per 1 km of strip laying. The productivity of the forest fire ground-throwing machine with a new energy- saving hydraulic drive increases by 16-22% while reducing energy consumption by 7-8%.
Method for determining malfunctions of hydraulic drives of high-speed equipment
Authors: Kobzev K , Vyalov S , Rybak A 
Published: December 2020

Abstract
The article discusses the control system of a hydraulic power source of constant pressure, which is a pump-storage power source, equipped with the original design of the automatic unloading of the hydraulic pump, which provides relay switching of its operation mode. A mathematical model is proposed, obtained using a modeling technique based on the application of the theory of volumetric rigidity of hydraulic systems and their elements. The results of a numerical experiment carried out by numerically solving the equations that make up the mathematical model of a power source are also presented. As a result of a numerical experiment, the main technical capabilities of the considered power source and the influence of its main structural parameters and functional features of the system on operational properties are revealed.