bluuebunny/crossref_metadata_2025 huggingface dataset:
Testing industrial laboratory dispersion method of Multi-Walled Carbon Nanotubes (MWCNTs) in aqueous medium
Authors: Rodriguez Carlos , Vélez Ederley , Restrepo Julián , Quintero Jorge H. , Acuña Rodrigo
Published: June 2019

The carbon nanotubes (CNTs) dispersion has gained interest in recent years due to its multiple applications in fields such as electronics, concrete, optics, environmental, automotive, marine and aeronautics coatings. In this sense it is necessary to develop stable dispersions of CNTs. On a laboratory scale the method of preparation of the CNTs is usually done using sonication, but this method is not appropriate to obtain CNTs dispersions on a larger scale. This work studies Multiwalled Carbon Nanotubes (MWCNTs) in aqueous medium comparing an industrial laboratory dispersion method vs traditional sonication. A factorial experimental design was performed, considering as variables: dispersion method, type of surfactant and use of a rheological modifier. The samples were prepared according to the full factorial DoE and properties such as electrical conductivity and pH were studied. Stability measurements were carried out over time and charge stability studies were performed using zeta potential measurements. The results shown the best combination of variables for the electrical conductivity was: dispersion method, sonication; dispersant, TX-100; rheological modifier, present. Although the results show that an improvement in CNTs dispersion is not achieved with the grinding and the use of industrial additives, the additive Disperbyk 2012 presented the highest value of electrical conductivity as a lonely compound, but the final electrical conductivity obtained when using it was not so high, it indicates that this additive must have specific conditions of activation, which implies that a further experimental work is required in order to get a suitable working window that allows a combination of variables with greater industrial application.
Parameters optimization in the casting processes of Fe32Cu64B4 magnetic alloys
Authors: Garzón D. , Arnache O. , Aristizabal R. , Santacruz Andrés , Ostos C. , Echavarría Alejandro
Published: June 2019

A Fe32Cu64B4 (FeCuB) alloy was obtained by using an induction furnace under an argon atmosphere. Parameters suitable in the casting processes like voltage, temperature and cooling times were optimized. Once the FeCuB alloy was melted and solidified, X-ray diffraction (XRD) and surface morphology analysis were performed through optical and scanning electron microscopy (SEM-EDX). The results showed that complete diffusion of the precursor elements (Fe, Fe2B, Cu) requires thermal homogenization treatments (2 and 4 hours) at 750° as suggested from phase diagram of FeCuB simulation. The XRD analysis revealed that the primary crystallization consists of a mixture of the fcc-FeCuB (79%) and bcc-FeCuB (21%), with a = 3.62Å, spatial group Fm-3m and a = 2.86Å, spatial group Im-3m respectively. Micrographic images show an average grain distribution of ∼ 135µm. Finally, long times of homogenization (4 hours) allow a greater uniformity and redistribution of grain boundaries, resulting in the formation of an equiaxed grain structure in the alloy.
Synthesis of Bi0.4Sr0.6FeO3-δ (BSF) powders and ceramics
Authors: Reales Rios M , Medina Barreto M H , Cruz Muñoz B
Published: June 2019

By mean of mechanical alloying the synthesis of Bi
0.4
Sr
0.6
FeO
3–δ ceramic powders were achieved according to the stoichiometric relations of Bi
2
O
3, Fe
2
O
3 and SrCO
3 initial powders. Then thermal treatments in air both 800 °C as 825 °C as at function on time was carried out on the processed ceramic powders, which were posteriorly characterized via X-ray diffraction and thermogravimetric. Finally, uniaxial compaction of the chosen processed powders to 800 °C was performed adding polyvinyl alcohol (PVA) or butyral alcohol (PVB) try to find a higher porosity. The milled ceramic compound presented a single cubic phase with lattice parameters of 3.95Ȧ when it was thermally treated at 800 °C and only 30 min of thermal treatment. No change on lattice parameter was found with higher treatment time. Thermogravimetric analysis showed processed powder are stable to work at the operation temperature of the solid oxide fuel cell chosen. In regard to porosity, the results showed that an adequate porosity 27 % with addition of PVB was achieved.
Grain Size Reduction Effect on Structural and Magnetic Properties in La1-xSrxMnO3 (x = 0.3 y 0.4) by Mechanical Ball Milling
Authors: Campillo G , Osorio J , Arnache O , Gil A , Beltrán J J , Dorkis L
Published: June 2019

We have investigated the magnetic, structural and morphological properties of ferromagnetic phases of manganite La1-xSrxMnO3 with x = 0.3 (LSMO-30) and x = 0.4 (LSMO-40) prepared by solid state reaction method, and then subjected to mechanical ball milling at different times of 3, 6 and 12 h. All of the samples were characterized by X-ray diffraction (XRD) and magnetic measurements. From Rietveld analysis of XRD patterns it was found a reduction in crystallite average size (Dv) with increasing milling time, for both concentrations. For LSMO-30 sample a mix of two different crystallographic structures, an orthorhombic phase (Pnma), and another rhombohedral (R3C) were identified at 3 and 6 h, but for 12 h of milling the R3C structure was the only phase identified. In contrast, for LSMO-40 the R3C structure was discerned as the unique phase independent of milling time. For both samples, a low value of the saturation magnetization was obtained for the longer milling time (smaller Dv). This behaviour was attributed to surface effects that induce magnetically disordered states with decreasing of particle size. This magnetic anisotropy surface was also evidenced on Zeta potential values and the changes of coercive fields, which increased most drastically with the first hours of mechanical ball milling time.
Implementation of a portable EDXRF measurement chain for characterization of metallic objects of cultural interest in Colombia
Authors: Julio Fabián S. , Felipe Ramírez Luis , Pimienta Hernán , Osorio Jaime , Oscar Arnache O.
Published: June 2019

The study of cultural heritage requires sophisticated equipment that does not alter or destroys the materials composing the objects under study. The main requirement about an artifact or an ancient work of art, for its restoration or conservation processes, is information about its constituting elements. Energy-dispersive X-ray fluorescence (EDXRF) is a very versatile and relatively inexpensive technique for conducting a nondestructive elemental analysis. In this paper, we present the design and implementation of a hand-hold X-ray fluorescence spectrometer. Although the EDXRF measurement chain appears to be a simple technique to assemble and use, it requires extensive knowledge about the proper handling of the X-ray beam, the analysis of the spectrum and whether the obtained spectrum is appropriate for a qualitative and quantitative analysis. Even geometry is one of the most important factors since the source-sample-detector distances must be handled with meticulousness to obtain optimal spectra. Acquisition time and the amount of accumulated counts to obtain high resolution spectral peaks are very important as well.

This work shows the results obtained from metallic samples of Colombian cultural interest belonging to the collection of Museo Universitario Universidad de Antioquia.
Design and Construction of a Muon Detector Prototype for Study the Galeras Volcano Internal Structure
Authors: Guerrero I.D. , Cabrera D.F. , Paz J.C. , Estrada J.D. , Villota C.A. , Velasco E.A. , Fajardo F.E. , Rodriguez O. , Rodriguez J. , Arturo D. , Dueñas D. , Torres D. , Ramirez J. , Revelo J. , Ortega G. , Benavides D. , Betancourt J. , Tapia A. , Martinez-Caicedo D.A.
Published: June 2019

Muon tomography is a technique based on the observation of the absorption of muons in matter, as the ordinary radiography does using X-rays. The interaction of cosmic rays with the atmosphere produce Extensive Air Showers, which provide an abundant source of muons. These particles can be used for multiple applications on muon tomography, in particular, to study the internal structure of different volcanoes edifices. It is necessary in any muon tomography experiment a particle detector that has the capability to be sensitive to muon interactions. Here we report a brief description of the first steps towards a complete design of a prototype particle detector to perform muon tomography in harsh conditions encountered in the surroundings of the Galeras Volcano. The mechanical design and fabrication processes of the supporting structure of the muon detector prototype, and first steps towards a future detector simulations on GEANT4 are described in this work.
Carbonation study in a cement matrix with carbon nanotubes
Authors: Rodriguez B. , Correa E. , Arias Y. P. , Quintero J.H. , Calderón J.A. , Mendoza O. A.
Published: June 2019

Carbon nanotubes as additions in Portland cement based matrices have a great potential to improve the mechanical properties of mortars and concretes; however, little work has been done regarding the effect that they have on the chemical durability of the cement matrix and reinforcing steel. In this work, carbon nanotubes are dispersed in water solution with Triton X 100 surfactant and blended in Portland cement mortars. A sharp decrease in compression resistance was observed at all curing ages (7, 14, 21 and 28 days) while a depth increase in the carbonation profile was found, which is associated with a decrease in the matrix durability.
Correlation between cross sectional area and torsion degree of fique yarns by image analysis system
Authors: Díaz-Ramírez G A , Sanchez H G , Cruz R A
Published: June 2019

The improvement of the natural fibers which are used in composite materials engineering applications depends on the reliable estimation of their mechanical properties, whose calculation is directly associated with the determination of their physical characteristics, such as cross-sectional area and diameter. The cross-sectional area of fique yarns, a natural fiber obtained from “furcraea andina” plant, consists in the sum of several singular fiber areas packaged thanks to the torsion effect of the spinning process. In this study, cross-sectional areas of fique yarns were obtained by optical micrographs, afterwards, the images were processed by two different approaches: the first one using Fiji, a specialized software for image processing; and the second one, through an own Matlab programming. The results obtained by both methods were compared and the respective diameter values for each fiber were extracted, assuming a circular shape of fique fibers cross-section. To perform the microscopic shots, fique yarns (0,877 and 0,714 tex) with torsion degrees of 1.5, 2.0 and 2.5 turns/inch were selected. The results indicated that even though linear density remain constant, the cross-sectional area varies with torsion degree. Additionally, the image analysis method allowed to improve the accuracy of calculations. It is expected that the measurement method proposed contributes to improving mechanical analysis of these type of materials in future studies.
Optical microresonator in form of hollow bottle for the measurement of hydrostatic pressure: A theoretical study of its sensitivity
Authors: Amador J , Avila D A , Horta S D
Published: June 2019

In this research, we report the theoretical study of an optical microresonator in form of hollow bottle for the measurement of hydrostatic pressure in microfluidics. The proposed device bases its operating principle on the excitation of the resonant modes WGMs that are confined to the interior of the optical cavity through the evanescent coupling of the light from the outside. The analytical study developed to determine the sensitivity of the device to changes in internal pressure in the hollow micro-bottle, is developed from a layer model with application of boundary conditions in the problem, where it is necessary to consider the excitation of the transverse modes WGMs and the elastic-optical effect produced by the internal pressurization of the resonant cavity. In the investigation we have concluded that the theoretical results present a good approximation with the experimental results using the layer model with which it is possible to optimize the design of this type of devices to improve the sensitivity for the measurement of the hydrostatic pressure in microfluidics.
Acoustic properties of concrete modified with an asphalt/styrene butadiene emulsion
Authors: Cruz R A , Correa C R , Díaz-Ramírez G A
Published: June 2019

This work describes the acoustic properties, such as absorption and reflection acoustic coefficients and noise reduction coefficient (NRC), and the mechanical strengthening of a modified asphaltic emulsion concrete. The asphalt emulsion has emulsifying agents, water and 62% asphalt, and has been mixed with styrene butadiene (SB) to 5% in asphalt weight. The concrete was made with high strength cement. Additionally, the concrete was modified with the SB emulsion at 5, 15 and 20% (CM5, CM15, CM20) of the cement weight. The results showed different coefficients depending on the wave frequency. CM20 shows the higher absorption coefficient. On lower frequencies, the concrete pattern (CP) and CM5 have higher reflection coefficients. CM20 indicated one hundred percent increase on the NRC related to CP. Al the same time, the compressive strength decreases proportionally to the amount of emulsion between 13 and 43% compared to the concrete pattern.
A Structure-from-Motion Pipeline for Generating Digital Elevation Models for Surface-Runoff Analysis
Authors: Meza Jhacson , Marrugo Andres G. , Ospina Gabriel , Guerrero Milton , Romero Lenny A.
Published: June 2019

Digital Elevation Models (DEMs) are used to derive information from the morphology of a land. The topographic attributes obtained from the DEM data allow the construction of watershed delineation useful for predicting the behavior of systems and for studying hydrological processes. Imagery acquired from Unmanned Aerial Vehicles (UAVs) and 3D photogrammetry techniques offer cost-effective advantages over other remote sensing methods such as LIDAR or RADAR. In particular, a high spatial resolution for measuring the terrain microtopography. In this work, we propose a Structure from Motion (SfM) pipeline using UAVs for generating high-resolution, high-quality DEMs for developing a rainfall-runoff model to study flood areas. SfM is a computer vision technique that simultaneously estimates the 3D coordinates of a scene and the pose of a camera that moves around it. The result is a 3D point cloud which we process to obtain a georeference model from the GPS information of the camera and ground control points. The pipeline is based on open source software OpenSfM and OpenDroneMap. Encouraging experimental results on a test land show that the produced DEMs meet the metrological requirements for developing a surface-runoff model.
Obtaining ZrN, ZrO, ZrC powder in a nitrogen atmosphere by means of a Ball Mill
Authors: Jaimes-Ochoa CJ , Quintero J.H. , Ospina R.
Published: June 2019

Properties such as thermal insulation, excellent structural and chemical stability, resistance to high temperatures make the zirconium compounds, their oxides and nitrides are of great interest to the scientific community. In the present work, the production of ZrN, ZrO and ZrC from a highly energetic ball mill is experimentally studied. The synthesized powders were characterized by X-Ray Photoelectron Spectroscopy and Scanning Electron Microscopy. The spectra performed demonstrate the ZrN, ZrO and ZrC formation, in addition the images obtained by SEM show a considerable increase in the size of the particles, since initially they were at 100 nm and were obtained in the order of 250 nm.
Search for ferroelectricity in fluoroperovskites: comparison between LiNiF3 and NaNiF3
Authors: Garcia-Castro A. C. , Quintero J. H. , Romero A. H.
Published: June 2019

Employing first-principles calculations, we have investigated the possible existence of the ferroelectric instability in the G-type antiferromagnetic NaNiF3 and LiNiF3 fluoroperovskites. The behavior of the unstable modes, at the cubic high-symmetry structure, is studied as a function of pressure. This study shows the vibrational landscape and define the conditions to drive the ferroelectricity in these materials, where the A-site dominates the polar instabilities.
A Kerr magnetometer setup in the kHz regime based on open-hardware architecture
Authors: Arroyave MA , Marín Ramírez JM , Campillo G , López JH , Arnache OL , Osorio J
Published: June 2019

A high sensitivity Kerr magnetometer (ΔI/I = 1/30) is presented, making use of open source hardware and software. By making time resolved measurements (up to 0.15 s/cycle) the signal quality has been greatly improved up to an order of magnitude, enabling us to compare our measurements with commercial vibrating sample magnetometers. We also present an additional setup to amplify the Kerr signal in a 25:1 scale, cleaning a large part of the electronic and trigger noise.
Density functional theory studies of the adsorption of Cr (VI) on Fe-(hydr) oxide: Gibbs free energies and pH effect
Authors: Acelas N Y , Flórez E
Published: June 2019

Adsorption of chromium (VI) on iron oxides is a potential removal method from industrial wastewater. Cr (VI) is a toxic specie for human health due to its easy mobility in the environment. Currently, US EPA drinking water standards establish a maximum Cr level of 100 μg/L. Since the adsorption process occurs in the solid/liquid interface, pH is one of the main factors that affect this process and it is a very important parameter to study. Understanding the adsorption process and the molecular geometries of complexes, is essential to predict the environmental transport of Cr (VI) and to develop appropriate models for the remediation of Cr (VI). Therefore, in this work, we describe the adsorption of Cr (VI) onto Fe-hydr (oxides) through computational methods. A complete characterization of the adsorbed surface complexes was performed, and three different pH conditions were simulated (acidic, intermediate and basic). It was found that, the thermodynamic favourability of the different adsorbed complexes was directly related to the pH. Bidentate complex (BB) was the most thermodynamically favourable complex with an adsorption energy of -143.3 kJ/mol under acidic pH conditions.
Monitoring and analysis of air quality for community empowerment in Environmental Health
Authors: Camilo Ordoñez Cristian , López Jennyfer , Guañarita Héctor A. , Armando Ordoñez José
Published: June 2019

The emission of greenhouse gases has increased dramatically. Among these, carbon monoxide (CO) has been identified as having the greatest negative impact on human health. These gases are produced mainly by human activities and, therefore, can be reduced if some community actions are carried out. This type of action is known as community empowerment and can be defined as active Participation of the community to achieve common objectives. The first step for empowerment is to know the magnitude of the problem, however, in the case of environmental monitoring, the price of the monitoring devices can be prohibitive. In this research, an air quality-monitoring platform based on the Internet of Things (IoT) is proposed. This platform uses Low-cost devices such as Arduino and Raspberry to measure the air quality in the center of Popayan city. The information is collected, processed and shared with the community through an app. The early results show an impact in the community perception. Also to the lessons learned, can be used to other low-cost developments.
Time temperature indicators (TTIs) based on silver nanoparticles for monitoring of perishables products
Authors: Lanza G A , Perez-Taborda JA , Avila A
Published: June 2019

This work presents the results of the production and characterization of silver nanoparticles (AgNPs) to applications in Time Temperature Indicators (TTIs). AgNPs were synthetized by chemical processes. The suspensions (AgNPs in water) were characterized for different temperatures (4°C and 22°C) and time (0 to 5h). The AgNPs were characterized by energy dispersive X-ray spectrometry (EDS), UV–vis spectrophotometry and dynamic light scattering (DLS). AgNPs with diameters between 40 to 160nm were produced. The UV-Vis spectra reveal a characteristic absorption peak of the Ag in 420nm. This suspension shows shifts in the emission wavelength when exposed to room temperature compared to when exposed to a temperature of 4°C for different periods of time. Δλ = 20nm in the absorption spectra were found. Size distribution showed that the nanoparticles size decreases from 164 ±8 nm to 44±3 nm in the period of time studied. Suspension with nanoparticles concentration of 1,26· 10-10 M were obtained. TTIs manufactured with nanomaterials base its operation on the variations of the characteristics of nanoparticles suspended due to absorbing heat.
The relationship of atmospheric air temperature and dew point temperature to extreme rainfall
Authors: Bui Andrew , Johnson Fiona , Wasko Conrad
Published: June 2019

To understand the expected changes of extreme rainfalls due to climate change, the sensitivity of rainfall to surface temperature is often calculated. However, as surface temperatures may not be a good indicator of atmospheric moisture, an alternative is to use atmospheric temperatures, but the use of atmospheric temperatures lacks precedent. Using radiosonde atmospheric temperature data at a range of geopotential heights from 34 weather stations across Australia and its territories, we examine whether atmospheric temperature can improve our understanding of rainfall-temperature sensitivities. There is considerable variability in the calculated sensitivity when using atmospheric air temperature, while atmospheric dew point temperature showed robust positive sensitivities, similar to when surface dew point temperature measurements were used. We conclude atmospheric dew point temperature may be a promising candidate for future investigations of empirically calculated sensitivities of rainfall to temperature but does not appear superior to the use of surface dew point temperature measurements.
Analysis of bamboo mechanical properties as construction eco-friendly materials to minimizing global warming effect
Authors: Yasin I , Priyanto A
Published: June 2019

Burning fossil fuels increases the amount of carbon dioxide in the atmosphere. Carbon dioxide is the main cause of the greenhouse effect and global warming. Climate change causes an increase in the number of human deaths due to diseases and natural disasters. In general, in the past decade there has been deforestation of 13 million ha / year. The highest deforestation rates (> 3.4 million ha / year) occur in South America and Africa while in Asia also experience deforestation in many places. Bamboo forests are very important especially in East and Southeast Asia as well as in Africa. The potential of bamboo is very large in controlling soil erosion, water conservation, land rehabilitation and carbon sequestration. In carbon sequestration bamboo contributes very significantly. The use of bamboo as an environmentally friendly construction material is very important to do. Testing of bamboo mechanical properties based on ISO 3129-1975 standards, which includes testing of fiber parallel compressive strength, parallel fiber shear strength, fiber parallel tensile strength and straight fiber tagak flexural strength. Setting-up testing is carried out after each specimen in the condition of the kiln dry water content is in the range 12-13% according to the requirements of the ISO 3129-1975 standard. Analysis of variants (Anova) of pressure treatment on bamboo material has an effect on some of the mechanical properties of bamboo. Pressure treatments up to 2.5 MPa have a significant effect on the elastic modulus, tensile strength and shear strength of bamboo while the compressive strength is not significantly affected by the pressure treatment of bamboo material. Bamboo forests have a big influence in reducing the impact of global warming and climate change.
Problem analysis on the work cycle of occupational safety and health management system in manufacturing industry
Authors: Ratnawati Dianna , Setuju S
Published: June 2019

The occurrence of work accidents affecting losses for the industry and workers. Prevention of negative impacts can be controlled through the occupational safety and health management system quality and integrated. This research aims to find the root of the problem in the work cycle occupational safety and health management system using problem tree analysis. This management cycle refers to the OHSAS 18001:2007 standard. This type of research is descriptive qualitative. Based on the results of data analysis, it was found the problems in the occupational safety and health management system at PT. Mega Andalas Kalasan includes the cycle of occupational safety and health policy, planning, implementation and operation, inspection and action to improve occupational safety and health, review of the occupational safety and health management system, and continuous improvement. Problems in each cycle will bring sustainable problems in the next cycle. Findings of problems in the cycle of occupational safety and health policy have an impact on the problems in the initial planning cycle, the weakness of the organization’s managerial planning will bring up problems in the implementation and operation cycles, budget constraints in the implementation and operation cycle raises the problem of the lack of real action cycle improvement of safety and health improvement actions work, the absence of formal socialization of audit results to workers in the review and management system of occupational health and safety has an impact on creating barriers to the cycle of continuous improvement.
The implementation of teaching factory in producing fly ash based eco-friendly concrete products
Authors: Inderawan NA , Widodo S
Published: June 2019

This literature study aimed to describe eco-friendly solutions for developing teaching factory models in vocational high schools by using Fly Ash wastes as cemet replacement materials. The need for eco-friendly concrete has become an innovation which is able to reduce the impacts of environmental pollutions and the concrete product has better quality than conventional concrete. Vocational High Schools in Indonesia have good potential to apply this idea by using teaching factory model for producing eco-friendly concrete because of multiple benefits: (1) reducing the amounts of fly ash wastes; (2) the result of this model is a good quality concrete product that gives benefit to society; (3) providing the understanding of Greening TVET to vocational high students; (4) students deepen their competencies by adapting Greening TVET; (5) also growing good cooperation between steam electricity power plant, vocational school, industry in the field of eco-friendly concrete, and market needs. This study reviewed the various studies about the characteristics and optimum mix design of fly ash as material mixture and teaching factory model. The result of study are idea and design of teaching factory model in Vocational High School by using fly ash as cement replacement of concrete mix design.
The concept of computational thinking toward information and communication technology learning
Authors: Harimurti R , Ekohariadi  , Munoto  , IGP Asto B
Published: June 2019

Computational thinking is a process of problems solving and designing systems using concepts in computer science. Computational thinking is based on a computational principle that involves a wide range of approaches and skills with applications in several disciplines. Computational thinking has been widely applied in the curriculum of various levels of education while still basing on the principles and characteristics of a strong computational thinking. To train the computational thinking to students it must include the computational thinking material in the compulsory material. This material needs to be held since the level of basic education with a simple problem level, the level of the material will increase along with the increase of education level. This article discusses the implementation of computational thinking on information and communication technology learning using a simple programming language that is Scratch. This programming language will make it easier for students to understand the concept of programming by using blocks so that students will easily learn. As a basis for information and communication technology learning, a measurement scale has been developed to measure students’ computational thinking ability. Computational thinking uses a five-point Likert scale consisting of 29 items from 5 developed indicators.
The development of realia for the planetary gear unit to improve students’ understanding on the basics of automatic transmission
Authors: Wakid M , Tafakur
Published: June 2019

This study aims to design and develop a real model of a planetary gear unit providing three kinds of simulation for the basic configurations of the planetary gear unit in which one component member is locked, two members are held together, and two input members works. This is a research and development (R&D) to develop a realia of the planetary gear unit for the learning of automatic transmission basics. The realia is expected to demonstrate how the configurations in which one component member is locked, two members are held together, and two input members moves. This study was carried out through ten stages, namely analyzing potentials and problems, needs analysis, product design, focus group discussion, product development, pilot study (small-scale field test), product revision, large-scale field test, product revision, and final product. The data were collected by questionnaires and were analyzed quantitatively. The product of this study is learning media in the form of realia made of acrylic so that the components are clearly visible and the work of basic configurations of the three gears in the planetary gear unit is easy to understand. These basic arangements can be operationalized on the learning media by applying brakes to the ring, carrier, and sun gears and applying cluthes between the sun and carrier gears, the sun and ring gears, and the carrier and ring gears. Evaluated from its performance, the realia of the planetary gear unit can work well. The shaft can rotate well though some friction generated, the clutch and brake can work on its function, as well as the constituent gears can rotate as its real version does. This is reinforced by the responses from the material and media experts that reveal the product meets the very feasible category.
Improving the compact crucible furnace performance by adding fins in heating chamber
Authors: Leman A , Tiwan  , Widarto  , Ardian A
Published: June 2019

A crucible furnace is developed continuously to obtain appropriate furnace in support casting practice at VHS. This research aimed at improving performance of compact crucible furnace by modification the heating chamber. Fins were placed at inner side of compact crucible furnace wall. The furnace performance determined by increasing of temperature rate to melt 3 kg of aluminium. Descriptive analysis is used to describe performance of modified compact crucible furnace. The fins addition on the inside wall improves the compact crucible furnace performance. The temperature rate is increase as the fins inclination angle increase. Fins with inclination angle of 800 could keep and maintain the temperature of heating chamber. Compact crucible furnace which added fin on the inside wall is able to melt 3 kg of aluminium in 35 minutes.
Automatic water filling and capping machine trainer kit programmable logic controller controller prototype for vocational high school learning validity
Authors: Sukir  , Yuniarti N , Yatmono S , Wicaksono T
Published: June 2019

The purpose of this article is to find out validity level PLC controlled automatic water filling and capping machine as trainer kit for learning in industry automation competence expertise in vocational high school. Research type used in this research is research and development (R&D) according to Robert Maribe Branch. carried out steps are; Analyze, Design, Develop, Implement, and Evaluate. Instrument used is questionnaire and observation sheet. Collected data is analyzed descriptively. Research result shown that validation toward automatic water filling and capping machine prototype as trainer kit for PC practical learning in vocational high school which done by media expert, material expert, and student shown result in very satisfactory category, indicated by: (1) media experts give average score 87.5% (very satisfactory); (2) material experts give average score of 86,9% (very satisfactory); and (3) student give average score of 95,3% (Very Good)
Water level control based fuzzy logic controller: simulation and experimental works
Authors: Khairudin M , Hastutiningsih AD , Maryadi THT , Pramono HS
Published: June 2019

This paper presents an automatic control system for Water Level Control (WLC) using Fuzzy Logic Controller (FLC). The use of FLC on the WLC system so that it can work automatically regulates the rotation speed of the motor (water pump). This system uses the input of Light-Dependent Sensor (LDR) as a light detector sensor outside space and ultrasonic detection sensors as the height of the water. As for the output of the motor rotation be as a replacement water pump for filling water in the reservoir of the water automatically. The working principle of this system is in a light sensor to detect outdoor LDR and Ultrasonic Sensor obstructed water level then the sensor will provide the input signal to the microcontroller in the form of Analog data when it is converted into a digital form signal using an Analog to Digital Converter (ADC). The data is processed using the FLC algorithm. The results show that the lighter in the outdoors and higher low water, the water-pumping Motor speed the faster or maximal. As for when the high water is medium and a bright light or daylight then the speed of motor rotation is medium and at the time of the highest water is maximal then the motor will die. Conversely, if the light on the outdoor is darker or at night and water levels are low or medium, the motor rotation speed will be medium too.
Machining industry’s contribution level in vocational high school revitalization
Authors: Wibowo A E , Munadi S
Published: June 2019

Revitalization of Vocational High Schools (VHS) is an effort to increase the role of all stakeholders in developing education. This study aimed to measure the level of machining industry contribution in VHS revitalization, especially in Machining Skills Competence in Yogyakarta Special Region (DIY). This study used descriptive research with quantitative approaches. The population was 20 machining industry in Yogyakarta Special Region. Samples were determined by saturated sampling techniques. The number of samples selected were 14 machining industries. Questionnaires were used to measure the level of the machining industry contribution in implementation of VHS revitalization. Instrument validation used logical and empirical validity tests. Quantitative data analysis techniques used descriptive analysis. The results of the study showed that the level of machining industry contribution in VHS’s revitalization, especially in Machining Skills Competence in DIY as a whole was in the “very low” category with a score of 42.67%.
A comparative study of the occupational health and safety implementation in the industries and vocational high schools in Yogyakarta
Authors: Styawan B , Sukardi T , Rahdiyanta D , Wijanarka B S , Ngadiyono Y
Published: June 2019

This study aims to describe the extent of the Occupational Health and Safety (OHS) implementation in the manufacturing industries compared with that in the Mechanical Engineering study program of the vocational high schools (VHSs) in Yogyakarta Special Region. It uses the qualitative descriptive statistical analysis with data collection techniques covering field studies with direct observation and interviews. The research participants, the employees of the manufacturing industries and the VHSs’ Mechanical Engineering teachers in Yogyakarta Special Region, were determined purposively. The results show that the application of OHS in the industrial workplaces is somehow better than that in the VHS’s Mechanical Engineering study program in the researched region. In general, the problems of the OHS application in VHSs are perhaps triggered by the lack of health and safety equipment, facilities, and infrastructure in the mechanical engineering workshops and the poor OHS management system (OHSMS). The recommendations made are that VHSs improve the OHSMS, conducting OHS education and training programs for the VHS teachers and staffs, and using rewards and sanctions for all of the school community members.
Developing learning media for power plant course
Authors: Surwi F , Yuniarti N , Zamtinah
Published: June 2019

This study aims to (1) develop an appropriate learning media for Power Plant Course, and (2) assess the feasibility of the developed learning media. This is a research and development study using the ADDIE model (Analysis, Design, Development, Implementation, and Evaluation). The research object was the Power Plant Course and the subjects were 30 students of Electrical Engineering Education Department, Faculty of Engineering, Yogyakarta State University. The data were collected by means of questionnaires on a 4-point Likert-type scale. This instrument was validated through expert judgement with the Delphi technique. The obtained data were then analyzed using qualitative descriptive technique. The final product of this research and development study was a learning media used in the Power Plant Course. The results of the feasibility test by the material and media experts as well as by the end users indicate that the developed media is “highly feasible” as the obtained mean scores are 3.41, 3.53, and 3.62 respectively.
The basics of preparation technology of titanium triboengineering oxide coatings and their tests
Authors: Bolotov A N , Novikov V V , Novikova O O
Published: June 2019

The paper describes the developed basics of the preparation technology of solid ceramic coatings on titanium and its alloys. The coatings have been formed by the method of microplasma surface oxidation in electrolytes of different composition. The authors have determined the modes of wear-resistant coating application on titanium alloy, which have significantly decreased coating porosity and made it possible to increase its wear resistance. They have also carried out physical and mechanical, as well as tribological tests of the materials obtained and formed a database of their actual properties. The paper shows that self-lubricating coatings can be operated for a long time at moderate loads and sliding speeds in friction units without using a lubricant. It also describes a newly developed and improved existing equipment to create coatings and study their tribological properties.
The effect of plasticization on the functional properties of thermoplastic polyurethane ureas
Authors: Senichev V Yu , Makarova M A , Savchuk A V , Slobodinyuk A I , Oshchepkova T E
Published: June 2019

Several series of plasticized segmented polyether urethane of linear structure which can be used as the polymer base of thermoplastic materials were synthesized. The possibility of obtaining thermoplastic segmented polyurethane ureas with a softening temperature of 100 ÷120°C when using isophorone diisocyanate as the main element for building polymer chains, and DEHS as a plasticizer was proven. The original method for the purification of aromatic amine 4,4′-methylene-bis(2-chloroaniline) used in the process of synthesizing polyurethane ureas as a chain extender was developed. The polymers obtained have a uniquely low glass transition temperature close to -100°C with a plasticizer concentration of not more than 40%. The strength of these materials is more than 10 MPa at room temperature, and it is more 40 MPa at -70°C.
Energy equations for the temperature three-dimensional boundary layer for the flow within boundary conditions of turbo machinery
Authors: Zuev A A , Kishkin A A , Zhuikov D A , Tolstopyatov M I , Savelyeva M V
Published: June 2019

The research generates an integral relation of the energy equations for the temperature three-dimensional boundary layer allowing to integrate surfaces of any shape to determine thickness of energy loss. An equation to determine thickness of energy loss is necessary to specify heat transfer law and local heat transfer coefficients within boundary conditions of turbo machinery cavities.
Electrical conductivity modelling of polypropylene composites with carbon fillers
Authors: Stepashkina A S , Chizhkova E A , Mishura T P , Tselms R N
Published: June 2019

Samples of a composite material based on polypropylene matrix and carbon fillers (carbon black and carbon nanofibers) were obtained. It was experimentally shown that the dependences of the electrical conductivity on the filler mass fraction have a threshold nature/When the mass fraction of the filler is higher than the threshold the values of the electrical conductivity increases by more than 8-10 orders. Determination of the electrical conductivity value near the percolation threshold is difficult. In the article the simulation method was proposed which considers the presence of a dielectric layer between the filler particles, presented a method for its evaluation: the percolation curve near the percolation threshold was described. A fairly good agreement between the experimental and theoretical values of conductivity for various geometries and types of fillers is shown in this work.
Mechanical properties of new functional composite materials based on polymeric binders
Authors: Sulaberidze V Sh , Mushenko V D , Mikheev V A , Skorniakova E A
Published: June 2019

Composite materials which include components (binding and fillers) that provide technological and operational characteristics were investigated. As a fillers AlN, Al(OH)3, SiO2, CaSi03powders are used. Binder – dimethylsiloxane rubber SKTN A + PMS silicone oil in 4:1 proportion. Studied composite materials are designed for dielectric coatings materials creation, which have a high thermal conductivity and do not support combustion (through the use of fillers with flame retardant properties). The results of experimental studies of the mechanical characteristics of composite materials based on siloxane binder and fillers in the form of fine powders AlN, Al(OH)3, SiO2, CaSi03are presented. The values of strength, coefficient of elasticity, relative elongation in tensile tests, modulus of elasticity in compression tests, Shore hardness are measured.
Study of the stability of dispersed systems based on polyaluminosilicates for 3D aerosol printing of ceramic layers of printed circuit boards
Authors: Ivanov A A , Polyushko V A , Khomyakov A Yu.
Published: June 2019

A composite material based on polyaluminosilicate and highly dispersed filler powders of AlN and Al2O3 has been synthesized by means of the sol-gel synthesis. The pH effect on the Zeta potential of highly dispersed filler powders of AlN and Al2O3 has been investigated. The effect of the Zeta potential of filler powders on the sol polyaluminosilicate stability has been studied. Ceramic coatings for printed circuit boards have been obtained by 3D aerosol printing.
Working position with recomposed production systems: devices
Authors: Bobrovskij Sergej , Gorshkov Boris , Zaides Semen , Fedorov Sergey , Zibrov Petr , Drachev Oleg , Khaimovich Alexander
Published: June 2019

The article presents the current trends in the recomposed work stand and the terminology used. Technical solutions were considered in order to optimize the use of this system type. Intermodular element of locating and fixing - multi-tiered was proposed. This device contains automatic plug-in units, layout - multi-tiered. Tiered layout does not always meet the requirements of the technical process. Industrial robot for automatic replacement of nodes was proposed.
Studying rigidity of the welded liner - composite shell construction
Authors: Egorov Anton V
Published: June 2019

The mechanical behaviour of an aluminium welded liner in a cylindrical metal composite vessel of high pressure made by winding on a linear carbon-filled plastic tape with tension is investigated. The resulting pressure of the wound composite shell on the welded liner is simulated by cooling the shell. It is believed that the weld is obtained by friction welding and has characteristics that are reduced in relation to the base material of the liner. The problem is solved in a geometrically and physically nonlinear formulation using a 3D solid element model, taking into account technological deviations and in real (current) time. The calculations were performed in the LS-DYNA software package in a dynamic formulation. It is shown that liner delamination from the sheath starts from the side of the circumferential weld in the area of technological deviations.
Method for determining the direction to the interference source without use of additional antennas
Authors: Kartsan I N , Malanina Yu N , Zhukov A O , Klimenko A V , Tsarev R Y
Published: June 2019

A method for determining the direction to the source of interference without the use of additional antennas is proposed. It provides interference suppression in the direction of the side lobes of the radiation pattern due to additional synthesis of the antenna pattern for the central beams without complicating the calculation algorithm and without using additional antennas.
Recursive clustering algorithm based on silhouette criterion maximization for sorting semiconductor devices by homogeneous batches
Authors: Golovanov S M , Orlov V I , Kazakovtsev L A , Popov A M
Published: June 2019

We propose a recursive algorithm for dividing a presumably mixed production batch of semiconductor devices into homogeneous groups (clusters) with the use of data of non-destructive testing, based on the maximization of the silhouette criterion in the sequential solving of the k-Means clustering problems. Based on the silhouette criterion, we formulate the concept of homogeneity of a production batch. The application of the developed algorithm to the problem of formation of homogeneous production batches of integrated circuits for space industry is illustrated with a computational example.
Development of technologies for the production of multi-component ligatures Al-Cu-B-C with high thermal characteristics
Authors: Bazhin V Yu , Alattar A L , Danilov I V
Published: June 2019

The purpose of research is to provide a competitive alternative to aluminum silicon alloys used in automotive applications. This alternate can be created by developing composites of Al-5%Cu alloy reinforced with B4C particulates with a low coefficient of thermal expansion. Stir casting can be used to produce Al-5%Cu alloys containing different ratios of B4C. The squeeze casting technique decreased the porosity of the final material. The composites exhibited a fairly uniform particle distribution throughout the alloy matrix.