bluuebunny/crossref_metadata_2025 huggingface dataset:
Systematic review of extracellular vesicle‐based treatments for lung injury: are EVs a potential therapy for COVID‐19?
Authors: Khalaj Kasra , Figueira Rebeca Lopes , Antounians Lina , Lauriti Giuseppe , Zani Augusto
Published: August 2020

Severe COVID‐19 infection results in bilateral interstitial pneumonia, often leading to acute respiratory distress syndrome (ARDS) and pulmonary fibrosis in survivors. Most patients with severe COVID‐19 infections who died had developed ARDS. Currently, ARDS is treated with supportive measures, but regenerative medicine approaches including extracellular vesicle (EV)‐based therapies have shown promise. Herein, we aimed to analyse whether EV‐based therapies could be effective in treating severe pulmonary conditions that affect COVID‐19 patients and to understand their relevance for an eventual therapeutic application to human patients. Using a defined search strategy, we conducted a systematic review of the literature and found 39 articles (2014–2020) that reported effects of EVs, mainly derived from stem cells, in lung injury models (one large animal study, none in human). EV treatment resulted in: (1) attenuation of inflammation (reduction of pro‐inflammatory cytokines and neutrophil infiltration, M2 macrophage polarization); (2) regeneration of alveolar epithelium (decreased apoptosis and stimulation of surfactant production); (3) repair of microvascular permeability (increased endothelial cell junction proteins); (4) prevention of fibrosis (reduced fibrin production). These effects were mediated by the release of EV cargo and identified factors including miRs‐126, −30b‐3p, −145, −27a‐3p, syndecan‐1, hepatocyte growth factor and angiopoietin‐1. This review indicates that EV‐based therapies hold great potential for COVID‐19 related lung injuries as they target multiple pathways and enhance tissue regeneration. However, before translating EV therapies into human clinical trials, efforts should be directed at developing good manufacturing practice solutions for EVs and testing optimal dosage and administration route in large animal models.
Validation of the model for predicting VAC RTD photonics
Authors: Shasurin V D , Vetrova N A , Kuimov E V
Published: August 2020

This paper discusses the processes of current transfer in resonant tunneling diodes during the transition from the region of positive differential conductivity to the region of negative differential conductivity. The behavior features of the self-consistent potential and tunnel transparency coefficient in the region of peak stresses are demonstrated.
Properties of the thermoplastic starch/polylactic acid blends compatibilized by hyperbranched polyester
Authors: Mesias R , Murillo E A
Published: August 2020

With the aim of to contribute to the employ of new compatibilizing agent and to the preparation of biodegradable materials, in this study were obtained thermoplastic starch/polylactic acid blends and was evaluated the compatibilizing effect of a hyperbranched polyester polyol of second generation modified with polylactic acid in these blends. The blends were prepared in a torque rheometer. In all cases the weight ratio of thermoplastic starch/polylactic acid was 50/50 wt%. The proportions of the compatibility were 5 wt%, 10 wt% 15 wt%, and 20 wt% regard to the total amount of thermoplastic starch and polylactic acid. The blends were characterized by infrared, thermogravimetric, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy and rheological analyses. Torque value decreased with the proportion of compatibilizing. Therefore, the compatibilizing also acted as plasticizing. By infrared analysis was observed that the increasing on the compatibilizing content enhanced the intensity of the signals corresponding to OH and C=O groups. By X-ray diffraction and differential scanning calorimetry analyses was observed a reduction of the crystallinity of the blends obtained with compatibilizing. By rheological analysis was evidenced the formation of a microstructure, which is able to elastically deform.
Evaluation of the methyl violet sorption capacity in waters with a bentonite based geopolymer material
Authors: López J A , Montaño A M , González C P , Medina L
Published: August 2020

In this study, bentonite geopolymer was used as a sorbent to remove methyl violet in aqueous solutions. Several parameters such as pH, sorbent dose and initial sorbate concentration were evaluated. The greater sorption effectiveness of bentonite geopolymer is observed at pH 2-3, and the greater sorption capacity of methyl violet by bentonite geopolymer occurs when the sorbent/sorbate ratio decreases. The study of sorption kinetics showed that the data fit the pseudo-second order model, where much of the sorption occurs during the first hour of contact, it was shown that the process prefers diffusion between pores. Sorption was adjusted to the isotherm of Langmuir, which indicated that the sorption is preferentially in monolayer. bentonite geopolymer proved to be an excellent candidate for removal of methyl violet in aqueous bodies.
Effects of synthesis conditions on sorption capacity methylene blue of coal gangue based geopolymer
Authors: Pinto L F , López J A , Montaño A M , González C P
Published: August 2020

In this work, coal gangue from the department of Cesar, Colombia, was used in the synthesis of a geopolymer by alkaline activation. The effect of the variation of the geopolymerization temperature and of four parameters on the composition of the activating solution was evaluated: SiO2/Al2O3, SiO2/Na2O, NaOH concentration and amount of H2O2. The geopolymer was characterized structurally by X-Ray diffraction and Fourier transform infrared spectroscopy. The sorption properties of methylene blue in aqueous solutions of geopolymer were studied through ultraviolet-visible spectrophotometry. Effects of various parameters such as pH value, geopolymer dose and initial concentration on the sorption capacity were studied. The adsorption kinetics and adsorption isotherm fitted well with the pseudo-second order model and Langmuir model, respectively. In the kinetic study it was evidenced that the adsorption equilibrium time was reached quickly, therefore this material constitutes a viable alternative for water decontamination.
Resilience in successful math and physics students
Authors: Rojas-Suárez J P , Vergel Ortega M , Gallardo Pérez H J
Published: August 2020

Resilience refers to the student’s ability to overcome emotional periods caused by adverse situations. In this sense, research aims to evaluate the relationship between academic performance in mathematics and physics and school success in higher education students. The research is framed within a quantitative, descriptive-comparative and micro-sociological methodological approach developed with data from primary sources. Data collection was transectional and the sample was 1500 students. The Wagnild and Young resilience scale was used. The results show that there is an important relationship between the level of demand, the application of mathematics and physics, abstraction and academic performance. Students develop emotional resilience skills that allow them to improve their quality of life. In conclusion, resilience is significantly related to all strengths of character, as well as to positive acceptance of change and personal competence. It was identified that, while resilience helps students to be more tolerant and to better understand what is happening in their environment, it is precisely in these challenges that the strengths of high educational performance are manifested. Successful students demonstrate skills in formal thinking, creative thinking, applying mathematics, physics and resilience, all of which impact on their quality of life.
Exploitation of chips and scrap aluminum through physical processes for the development of aluminum sheets and bars
Authors: Perez-Rangel N Y , Florez-Solano E , Hoyos Palacio L M
Published: August 2020

Colombia manufactures metals such as iron and aluminum, which consume a lot of energy to carry out these processes. There are many techniques to recycle metals and other elements to reduce the amount of energy in manufacturing processes, since smelting is generated with already manufactured materials, as in the case of aluminum, which uses recycled products such as soft drinks and beer cans. In addition, there is another type of scrap metal, such as aluminum shavings generated by machining processes, with an amount that varies from a small percentage to 70-90% of the original part. This project seeks to transform the aluminum shavings through physical processes with the application of temperature in aluminum material to be used again. The process begins with the collection of chips from mechanical workshops, in this case, from the machine tool laboratories of the “Universidad Francisco de Paula Santander, Ocaña, Colombia”. Standard procedures will be carried out before the casting process by developing firing curves and phase diagrams of aluminum, where the research focuses on generating aluminum metal to be used again in the laboratories of the same university.
Development of an automated system for the determination of thermal conductivity in granular materials
Authors: Espinel-Blanco E , Arévalo-Ruedas J H , Florez-Solano E
Published: August 2020

In many devices such as refrigerators, ovens, industrial kitchens, integrated circuits among others, where heat transfer is involved, it is important to know the thermal behavior of the material and the geometric model (cylindrical, spherical, etc.), with which such equipment will be built, to subsequently perform analysis of the parameters evaluated and thus enhance their efficiency. For this reason, it is important to know variables such as thermal conductivity, wall thickness, material, and geometry for new generation equipment. As a result, this work involved the construction of a test bench for the analysis of thermal conductivity in insulating materials, which began with the selection of the components that made up the device, such as resistors, types of thermocouples, specimen geometry, sensors, and finally, the construction of a data acquisition and analysis control system using Arduino and Labview. Subsequently, a device was obtained to measure the temperature in the cylindrical walls with different granular materials. This project was developed in an innovative way, where the thermal behavior of non-pure agglomerated granular materials will generate research in the study area, with the purpose of implementing it in different projects in which heat transfer is involved.
Comparative experimental analysis of thermodynamic performance of heat pipe and water in glass solar collectors
Authors: Rolon Ortiz H A , Krenzinger A , Ferreira C , Prieb C
Published: August 2020

Solar energy plays an important role in the alternative energy mix. Solar thermal energy is used in many processes such as domestic water heating, pasteurization, desalination, ambient heating and power generation. There are many devices designed to make use of the radiation coming from the Sun. Evacuated tube solar collectors are one of them. They can be classified according to the employed heat transfer mechanism: direct transfer (water in glass) and indirect transfer (heat pipe). This ongoing work aims to characterize both types of collectors and make an experimental comparative of the thermodynamic performance under the environmental conditions of Porto Alegre, Brazil. An experimental rig was set up with two collectors, one water-in-glass and the other a heat pipe type. Both collectors were connected in series on a tilted plane, together with a global radiation sensor and temperature sensors on interest points namely: inputs and outputs of collectors, air temperature and storage tank. These sensors were connected to a data logger system. Preliminary results show that the heat pipe collector has an average efficiency of 20% superior to the water-in-glass collector.
Numerical simulation of coarse particle pipeline transportation based on Eulerian Lagrangian model
Authors: Wang Sibo , Ding Xuewen , Wang Jin
Published: August 2020

In this paper, based on the Eulerian Lagrangian model, the non-phase change flow process of the coarse particle slurry in the horizontal pipeline is studied. The particle motion state is tracked, the dynamic characteristics of the coarse particle slurry in the pipeline transportation are explored, and the resistance characteristics of the pipeline and the operation stability under different conditions are analyzed. The comparison of the results of velocity distribution, concentration distribution and pressure curve with the empirical formula and experimental data shows that the simulation results are in good agreement with the calculation results of wasp formula and the experimental values of Roco&Balakrishnam, and the simulation can better describe the flow characteristics in the basin. In addition, the flow characteristics of particles are further analyzed according to the key factors such as the flow stability, the transition process and the critical deposition velocity of particles in different positions of the pipeline.
Study on Pollutant Emission in a Natural Draft Dry Cooling tower with Flue Gas Injection based on LES
Authors: Zhou Ying , Xu Haihong , Xu Zhen , Ding Li
Published: August 2020

This study investigated the Computational Fluid Dynamics (CFD) simulation of pollutant emission in a natural draft dry cooling tower (NDDCT) with flue gas injection. In order to predict the diffusion and distribution characteristics of the pollutant more accurately, Large Eddy Simulation (LES) was applied to predict the flow field and pollutant concentration field and compared with Reynolds Average Navier-Stokes (RANS). The relationship between pollutant concentration pulsation and velocity pulsation is emphatically analyzed. The results show that the maximum value of LES is about 43 times that of RANS for the prediction of pollutant concentration in the inner shell of cooling tower. Compared with RANS, LES can simulate flow field pulsation with a smaller scale and higher frequency.
Analysis of the Influence of Cyclone Structure Characteristics on Combustion Chamber Performance
Authors: Xiang Wenwei , Liu Jiang , Weng Peifen , Fu Zaiguo
Published: August 2020

The cyclone is an important part of the combustion chamber of the gas turbine and has a direct impact on the combustion performance in the combustion chamber. Therefore, it is of great value to study the structural characteristics of the cyclone. This paper firstly analyses the structural characteristics of cyclone that have the greatest impact on the performance of the combustion chamber through the relevant data and the structural parameters of the actual combustion chamber. Then appropriately simplifies the structure of the combustion chamber, designing a F-class combustion chamber with cyclone. Numerical simulation method is compared with the actual combustion chamber data to verify whether the design of the cyclone meets the requirements, thus preliminary determining the blade installation structure and the number of blades of the combustion chamber cyclone. In the end, using the model combustion chamber as a blueprint, adjust the blade characteristics of the cyclone for different installation angles (40°, 45°, and 50°) and the number of blades (6, 8, and 10). The combustion chamber model is simulated to determine that the flow field of the combustion chamber is the best when the angle is 45°and the number of blades is 8.
Numerical study on the heat transfer performance of a novel spray tower
Authors: Zhu Shengkui , Zhu Qunzhi
Published: August 2020

In order to reduce the moisture content of flue gas in coal-fired power plants, this paper puts forward a novel spraying system with upward spraying and downward gas flow (ST-UD). And the heat and mass transfer models of ST-UD in fluent were validated against experiment data. Then orthogonal simulation experiment was carried out to get the relationship between the four influence factors and the two evaluation indices. Through the range analysis and trend analysis, it can be found that the influence degree and the influence trend of factors on evaluation indices. The conclusion of this paper provides a reference for the heat-transfer performance optimization of other spray towers.
Structural Design and Numerical Simulation of FDM Molding Chamber Based on Thermal-Fluid-Structure Coupling
Authors: Liu Yajie , He Bing , Chen Pengfei
Published: August 2020

Four different design of FDM molding chamber with hot air circulation were proposed to meet the requirements of temperature uniformity of FDM rapid prototyping equipment. Fluid and solid domain model of FDM molding chamber was established by finite numerical simulation method in order to analyze the influence of the heating rod, blower, air inlet and outlet position on the temperature uniformity and air flow. The results show that the temperature uniformity and air velocity evenness are highest when the heating rod is located on both sides of the molding chamber, the blower is lied at the bottom, the air inlet is located above the left side, and the air outlet is above the right side. And the temperature uniformity is up to 99%. FDM molding chamber prototype was developed according to the simulation results. Air flows evenly, and temperature uniformity is as high as 97.66%, which verified the accuracy and effectiveness of the simulation results deeply.
Research on the Method of Improving the Flow Field Quality in the Elbow of the Water Flow Standard Device Based on the CFD Numerical Calculation Method
Authors: Li Haiyang , Li Xuejing , Zhang Ping , Liu Yiping , Yao Xinhong , Zhang Jinming
Published: August 2020

To solve the problems of secondary flow, turbulent vortex, and instability of the flow field in the elbow of the water flow standard device, some 3D geometric models of the elbow were established, and the flow field numeral calculations of the elbows were carried out based on the 3D models. The study shows that appropriately increasing the turning angle and the number of deflectors has a significant effect on improving the flow field quality in the elbow. While it is not obvious that the effect of increasing the thickness of the deflector on the flow field quality, and which may increase the requirements for the power source of the standard device. It is concluded that the elbow with a 135°turning angle and 2 pieces deflectors may be the optimal choice.
Rising Characteristics of a Methane Bubble under Different Conditions: A CFD Study
Authors: Mulbah Christian , Mao Ning , Zhang Wei , Yongphet Piyaphong
Published: August 2020

For a methane (CH4) bubble rising in liquid, knowledge of bubble rising characteristics is crucial for the comprehension of methane dissolution rate and the inter-phase mass transfer. Here, the investigation of a methane bubble was performed using the computational fluid dynamics (CFD) technique and the volume of fluid (VOF) two-phase model. The deionized water of 13 MPa and 5°C was used as the carrier of the rising bubble. Bubbles with diameters ranging from 3.0–6.0 mm were selected. The results show that the bubble instantaneous liquid velocity distribution and the wake structure manifest unique characteristics under such a high-pressure and low-temperature condition. The bubbly flow involves complicated vortex structures. Moreover, the bubble velocity is relatively low relative to those obtained under general conditions. A non-dimensional analysis of the bubble behavior indicates that the results obtained here deviate significantly from available results obtained under general conditions. The bubble diameter significantly influences the drag coefficient.
Numerical simulation of the gas–liquid two-phase flow in aeration tank based on different multiphase models
Authors: Guo Jinnan , Dong Liang , Liu Jiawei
Published: August 2020

In this paper, the Eulerian model and Mixture model are used to study the free surface, internal flow and mass transfer in the aeration tank. The two multiphase models affect the liquid velocity, internal flow and oxygen mass transfer coefficient (kLa) of the tank. Eulerian model than the Mixture model significantly higher simulates the liquid velocity near the impeller, and the range of the main longitudinal circulation vortex is smaller than Mixture model. The error between the simulated kLa of Eulerian model and the experimental value is smaller than Mixture model. The results show that the Eulerian model is more suitable for the simulation of the gas–liquid two-phase flow in the aeration tank.
Numerical Study on Gas Transport in Shale Kerogen with Adsorption Effect Using LBM
Authors: Peng Zhigao
Published: August 2020

Gas transport and storage mechanism in gas reservoirs with complex pore size distribution play a key role in gas production. In the nano-scale, during the process of density disturbance caused by depressurization development, notable output gas collides with the wall as they convey along the channel. The continuum assumption of fluid flow is therefore invalid, and taking the influence of particles to collide with solid walls into account is necessary. The effective viscosity and slip boundary conditions were introduced in the simulation. Meanwhile, because of the adsorption effect is one of the most important intrinsic properties of shale, the impact of surface adsorption on the solid wall by using Langmuir adsorption kinetics was also involved in our investigation. In this work, a unified LB model was developed for gas multiple transports and surface adsorption in nanopores. In the model, the double distribution function was employed for a coupled bulk flow and gas diffusion model. The model is valid within the range of the continuum regime to the transition regime and has been verified by the analytical solution and the results of some previously published works. The results show that (1) the driven force of the fluid, the combination coefficient of slippage and the Knudsen number of the flow have an impact on the adsorption rate, (2) adsorption effect only directly influence the local small region of the solid surface, and the induced concentration gradient makes the global concentration variation, (3) once acting the surface adsorption on the boundary, the flux falls more significant as Knudsen number increases.
Waste recycling as an aspect of the transition to a circular economy
Authors: Rumyantseva A , Rumyantseva E , Berezyuk M , Plastinina J
Published: August 2020

A necessary condition for a successful transition to a circular or closed economy is the creation of sufficient capacity for sorting and recycling of production and consumption waste. According to experts, annually more than 10 million tons of tires go out of use in the world, only in Russia every 4–5 years the increase in used tires will be about 2 million tons, which creates serious environmental and economic problems. This research is aimed at solving the problem of recycling accumulated and formed waste tires. The article provides a comparative analysis of tire recycling methods, proves the choice of pyrolysis method and estimates the environmental and economic efficiency of the project of a plant for processing used tires by pyrolysis.
Accumulation of Heavy Metals by Fungi in the Cities of Central Black Earth Region
Authors: Nevedrov N P , Protsenko E P , Balabina N A , Balabina I P
Published: August 2020

Emissions of heavy metals into the environment lead to their accumulation in living organisms. This article presents the data on the accumulation of heavy metals in the fungi fruit in urban ecotopes of cities in the Western part of the Central Black Earth region. The features of accumulation of heavy metals by macromycetes of different taxonomic affiliation and ecological specialization under multi-level anthropogenic burden are studied. It was noted that MAC of Cadmium (Cd) in edible fungi can be in large excess over 88 times, lead (Pb) – 87 times, copper (Cu) – 6.8 times, zink (Zn) – 6.1 times. The accumulation of heavy metals by macromycetes can be determined by the degree of soil pollution, the bioavailability of heavy metals, as well as environmental specialization of fungi. The highest concentrations of heavy metals were recorded in the fruit bodies of soil and litter saprophytes. Cantharellus cibarius (L.), Murrill, Agaricus melleus (Vahl), Agaricus equestris L. were universal accumulators of Cd, Zn and Cu. Leccinum scabrum (Bull.) Gray, Kuehneromyces mutabilis (Schaeff.) Singer & A.H. Sm., Myxocollybia velutipes (Curtis) Singer are defined as selective Cd accumulators.
The impact of the COVID-19 related lockdowns on air quality
Authors: Bogomolova Arina , Balk Igor , Polkovnikova Natalia , Ivaschenko Natalya
Published: August 2020

Lockdowns imposed on population around the world due to COVID-19 provided unique opportunity to study impact of humankind of the environment. In this paper we discuss the magnitude of the anthropogenic impact on climate change, and in particular on-air pollution, since these two phenomena are interconnected. We used daily data on air pollution in several large cities, where serious restrictive measures were introduced in the context of a pandemic for a large number of citizens. The study period includes several months of 2020, including the moment of quarantine introduction, as well as the same period of 2019. Thus, we will check whether the impact of human activities on climate change is significant.
Modern Methods of Project Management in Road Traffic Organization
Authors: Ertman S A , Ertman J A , Gavaev A S , Morozov G N
Published: August 2020

Transport service of the population is a difficult task. The efficiency of transportation processes depends on the road traffic organization. The road traffic organization requires modern approaches to solve the tasks and emerging problems. The concept «Lean Six Sigma » could be one such approach, which will be new tool to solve the road traffic organization problems. The article describes the example of improving the road traffic organization with using the concept of «Lean Six Sigma» on the street and road network section. The used tools in each phase of the «Six Sigma» project life cycle are listed.
Ecological State of the Oka River in the Orel Region as an Indicator of Regional Environmental Policy
Authors: Kondrashova I N , Kondykova N N , Tikhii V I , Frolova N V , Tyapkina A P
Published: August 2020

This article is devoted to the analysis of the current state of the Oka River as a peculiar reflection of the specificity and effectiveness of regional environmental policy. The article describes the Oka River, the largest tributary of the Volga River. Ecological and geographical features of the river and its riverfront are considered. The main anthropogenic impacts on the river are analyzed. The results of studies of the water quality of the Oka River within the city of Oryol are presented, and the ecological state of the river is estimated.
Preservation of Forest Biological Diversity as an Activity to Ensure Environmental Safety in Forestry
Authors: Abanina E N , Pandakov K G , Timofeev L A , Suhova E A , Ustinova A N
Published: August 2020

It is necessary to ensure the ecological safety of forestry as a whole for maintaining the state of forest ecosystems. Taking into account the negative impact of human economic activity, activities for the preservation of individual forest objects that are of paramount importance for the functioning of the entire forest ecosystem are of particular importance. Such objects are called objects of forest biological diversity. Forest biological diversity exceeds that of other terrestrial ecosystems. Maintenance in forests of historically developed landscapes and ecosystems in general, which are not only a set of trees valuable for forest biological diversity, but also are the habitat of various groups of living organisms, is a prerequisite for ensuring environmental safety in forestry. The article examines the main problems arising in the preservation of forest biological diversity in Russia. Forest objects with different forest presentation duty (permissions, restrictions, prohibitions) are considered, difficulties with fixing such objects in the documents of users of forest services and on the ground are revealed. The article concludes with a number of recommendations for future studies of forest biological diversity in order to develop common approaches regardless of the state-owner of natural (forest) objects and peculiarities of national legislation.
Environmental Quality Assessment of Urban Areas Using Geoinformation Technologies (on Example of the Cities of Central Russia)
Authors: Shekoyan S V , Yeprintsev S A , Vinogradov P M , Lepeshkina L A , Voronin A A
Published: August 2020

On the example of the urbanized territories of Central Russia (the cities of Voronezh, Lipetsk, Kursk, Belgorod, Tambov and others) geoecological aspects of environmental quality are considered. The content of anthropogenic pollutants in natural environments has been estimated. In the GIS environment, the levels of environmental risk for the population of large cities are calculated. A comprehensive geoecological zoning of the studied urbanized territories was carried out. Based on geoinformation technologies, a scheme of environmental and geochemical monitoring of an industrialized city has been developed.
The Role of Big Data in Improving E-Learning Transition
Authors: Moharm Karim , Eltahan Muhammed
Published: August 2020

Educational organizations are operating in a dynamic competitive environment. Online learning, education, emerging technologies, and the number of learners are growing very fast and produce big data that contain meaningful information to be extracted and processed. The idea of applying the big data in e-learning supports developing and analyzing the students as well as the educational organization’s stakeholders. A big data framework architecture, methods, and tools in the e-learning platform are introduced. The paper studies briefly the opportunities of big data deployment in the educational sector and the value that the students and organizations gain. However, it also highlights the challenges and future research directions as the tool’s selection and value extraction from complex educational data sets.
BLDC motor design by applying the control of direct current and analysis of loading mechanism soft starting
Authors: Wirandi M , Safril  , Sumasto F , Agus M , Imansuri F
Published: August 2020

In this research, there will be a design driver brushless DC (BLDC), which on the input voltage of the motor driver applying direct current controllers and the implementation mechanism of soft starting the operator of BLDC, which uses fuzzy logic controllers. Testing is done with a view of controlling the application of direct current to the BLDC to many conditions, namely the amount of value given fuzzy logic and the load that is given to the mechanics. The design of the driving BLDC has successfully created and implemented by applying a direct current control and the results obtained in the form of efficiency that is better than the previous design. The soft starting mechanism that controls using the fuzzy logic method possible produces a low inrush current and generates steady conditions that are better on BLDC. For values that are applied to the load, the greater the torque load placed on the BLDC, the higher the initial current needed to achieve transient time equally and opposite that the smaller the torque load placed on the BLDC, then the lower torque the load required to achieve the transient time.
The Relationship of Temperature and Compressive Strength on Geopolymer Mortar using Fly Ash-Based
Authors: Bachtiar E , Marzuki I , Erdawaty  , Junaedy M F , Ramadhan F , Setiawan A M , Rachim F
Published: August 2020

Infrastructure development in Indonesia has increased. Therefore, the use of cement has increased as well. For this reason, it is necessary to replace the replacement cement material with environmentally friendly material. Fly ash is one of the waste materials that can be used as a substitute for cement. The purpose of this paper is to determine the compressive strength values of geopolymer mortars using fly ash-based from different Thermal Power Station and to determine the relationship of temperature curing with the compressive strength on geopolymer mortars using fly ash-based. The fly ash used was obtained from two Thermal Power Station in South Sulawesi, Indonesia. The sample is in the form of a cube with 5 cm × 5 cm size, with variations in room temperature; 65°C, 85°C, and 105°C. Activators used were Na2SiO3 and NaOH with 10 M with a ratio of Na2SiO3 per NaOH of 2. Compressive strength tests were carried out at 28 days. From the results of the study that the compressive strength of geopolymer mortar based on fly ash-Thermal Power Station A is higher than the compressive strength value of geopolymer mortar based on fly ash - Thermal Power Station B. The relationship of compressive strength with curing treatment with geopolymer mortar temperature variations is very significant. The higher the temperature, the higher the compressive strength of the mortar.
Automatic buoy system for position control based on global positioning system (GPS)
Authors: Akbar Z , Hasanuddin Z B , Salam A E U
Published: August 2020

This study aims to design a buoy using an electric motor as a driver to maintain the position based on the coordinates of the Global Positioning System (GPS) that has been determined. This control system is designed to replace the existing buoy system, namely a buoy using a chain to maintain its position. The method used in the study is an electric motor control method using a microcontroller with GPS coordinates as the return point (home coordinates). The solar cell system that connected to the battery is used as a source of energy for the buoy control system. The result of this device is the distance between the return point and the stop point of less than 12 meters.
The manufacture of automatic chicken feed making machines as an economical solution for chicken farmers in Indonesia
Authors: Rapi Amrin , Arifin Abdul Nasser , Lando Asiyanthi Tabran
Published: August 2020

Currently laying hens have a good chance to be developed in Indonesia, this breeding business experiences rapid development every year. The chicken farming industry has very interesting potential to be developed but there are still challenges in its development. One of the biggest challenges faced by chicken farmers in Indonesia today is the high cost of feed that they have to spend around 70% - 80% of the annual production cost. On the other hand, the key to success in the chicken farming industry is strongly influenced by meeting the need for adequate feed, both in quality and in quantity, this is because the feeding that is in accordance with the nutritional needs of chickens affects the amount and quality of produced. Based on these problems, we assume that the independent supply of poultry feed by breeders by providing livestock feed making machines using equipment and components that are widely available on the market today is an economic solution that can reduce production costs in a chicken farming industry in Indonesia. The manufacture of automatic chicken feed making machines 2.02 kg / hr for laying hens using 1400 rpm electric motor and automatic control system is expected to be an economical and practical solution in improving the quality of production of the chicken farm industry in Indonesia.
Analysis of time acceleration using Critical Path Method (CPM) to increase motorcycle maintenance in authorized service station
Authors: Marit I Y , Nursanti E , Vitasari P
Published: August 2020

Numerous studies have shown that maintenance requires proper scheduling by using preventive and corrective maintenance scheduling to maintain the state of the machine. The fact is the number of Honda motorcycle products has increased. This has resulted in a long motorcycle queue. Motorcycle queues cannot be prevented only by scheduling preventive and corrective maintenance, so scheduling of maintenance activities is necessity to speed up motorcycle maintenance time. This study uses the Critical Path Method (CPM) activity scheduling method with the help of the POM-QM program to increase the acceleration of maintenance time. Scheduling is made by calculating the logic of dependency and time of each maintenance activity. Activity scheduling is carried out on 7 types of maintenance, namely carburetor light service, carburetor and CVT light service, injection light service, injection and CVT light service, oil change, spare part replacement, oil and spare part replacement and final inspection of each type of maintenance. After that, the analysis of the scheduling results is done by comparing the results before and after the proposed improvement. Based on the results of research conducted it can be seen that the maintenance time at the authorized service station can be accelerated by using the CPM scheduling method. The efficiency of acceleration of maintenance time is 16.666% to 57.889%. The preparation of maintenance activities and processing of heavy service data is required if there is heavy service maintenance in the authorized service station.
Upscaling of 2D mineralogical information to 3D volumes for geoscience applications using a multi-scale, multi-modal and multi-dimensional approach
Authors: Butcher A R
Published: August 2020

Bridging the scales of geological observation is an on-going challenge to earth scientists, but recent advances in the development of 2D and 3D imaging and analysis technology has allowed a workflow to be developed that starts to make this possible. Using concepts borrowed from allied industries (petroleum geoscience and materials science), this study shows how a multi-scale, multi-modal and multi-dimensional approach can lead to a better understanding of rock’s mineralogy and texture, especially ore-bearing drill cores, which in turn can be useful for elucidating the meso- and macro-features of ore bodies, leading ultimately to improved mineral exploration success.
Identification of Cu-Co-oxide phases of reactive air brazed Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Ag-14CuO joints by EBSD, EPMA and TEM diffraction
Authors: Ehle L C , Richter S , Herzog S , Broeckmann C , Mayer J
Published: August 2020

The oxygen transport membrane Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) was wetted by the reactive air brazing alloy Ag-14CuO. Triple point phases of different cobalt-copper-oxides are formed in the reaction zone and are origin of micro-cracks and stress concentration. Therefore, their identification is necessary for understanding the microstructure evolution and designing the interface structure advantageously by an adapted brazing process. However, as the cobalt-copper-oxide system can form many different oxides with solubility of Co and Cu respectively, different analytical methods are necessary for identification. TEM diffraction is used for the correct identification of the occurring crystal structures, EBSD is used for analysis of composition, arrangement and orientation of the triple point phases and EPMA is used to confirm the crystal structures identified by EBSD and to determine the elemental concentrations. As the triple point phases consist of small grains with unpredictable forms and especially, Cu-Kα can excite Co-Kα by characteristic secondary fluorescence, different evaluation procedures for EPMA are performed on FIB lamellae: 1) Approach based on standard lamellae, where FIB lamellae from standards are used to determine the k-factor in dependence of the mass thickness t/λ, and 2) Monte Carlo simulation approach, where an iterative procedure is used to calculate the k-ratios, based on bulk standards. The use of FIB lamellae allows excluding the fluorescence effect and incorrect Monte Carlo simulations due to incorrect assumptions of the microstructure below the surface, which is within the excitation volume.
Characterisation of super duplex stainless steel by optimisation of EBSD parameters
Authors: Haukali M , Westermann I , Karlsen M , Yu Y , de Kloe R , Hjelen J
Published: August 2020

Electron backscatter diffraction (EBSD) was used to characterise the microstructure of a super duplex stainless steel (SDSS) alloy Zeron 100 and the intermetallic phases sigma and chi in this material. The material was analysed in three conditions; as-received, heat-treated at 900 °C for 8 min and heat-treated at 750 °C for 4 h. Heat treatments were performed to introduce the intermetallic phases in the steel. It is difficult to get reliable indexing of the sigma and chi phases due to noisy and overlapping patterns. To get the best results, the Hough transformation parameters were optimised and an averaging technique was used. The optimisation was done by removing some of the reflectors in the sigma- and chi-phases in the original TSL material files used for pattern indexing. By changing Hough parameters, considerable improvements in the indexing of the patterns were observed along with the increase of average confidence index (CI) value for both intermetallic phases. The applied SEM, Zeiss Ultra 55 FESEM was equipped with a NORDIF UF-1100 EBSD detector to acquire and stream patterns to HD. Indexing and data processing were performed by TSL/OIM 7.3. In the present study, at the most four different phases are present in the SDSS.
Evolution of crystalline orientations in the production of ferritic stainless steel
Authors: Núñez Galindo A , Collado Garcia I , Sales D L , Almagro Bello J F
Published: August 2020

Ferritic stainless steel EN 1.4016 is used in a wide range of applications, the most common ones related to sheet forming. Several problems in the post-processing of these steels relates to their texture and anisotropy. Therefore, it is necessary to know the mechanisms of texture formation in the subsequent stages of metal manufacturing processes. EBSD has been demonstrated as a successful characterisation technique for this purpose.

It is known that during re-crystallisation of Fe-Cr steels, deviations from the desired γ-fibre texture promote a decrease of deep drawability. Additionally, α-fibre damages formability. Subsequent cold rolling and annealing can enhance the deep drawing properties of the steel sheet. In this research, a standard sample and a modified one with optimised settings as regard to chemical composition and manufacturing process, to improve the formability properties, are characterised.

To analyse the preferred orientation and the type of main fibre present in the material, ODF and Aztec Reclassify Phase, to calculate the content of martensite, were used.
Development and validation of standardless and standards-based X-ray microanalysis
Authors: Pinard P T , Protheroe A , Holland J , Burgess S , Statham P J
Published: August 2020

We describe one approach to standardless quantification for energy-dispersive (ED) X-ray spectrometry that can achieved unnormalised results with an accuracy better than 5 %. This approach relies on a “factory” standards database, a model of the detector efficiency, calculated peak profiles, and a multi-step process to correct spectral artefacts and extract X-ray intensities from ED spectra. These processes and components, as well as the underlying equations involved in the quantification are detailed to illustrate the similarities between this approach and the classical standard-based k-ratio quantification. The accuracy was assessed by measuring and quantifying standard samples at different accelerating voltages (15 and 20 kV) and input count rates (50 and 200 kcps). In all cases, the measured, unnormalised concentrations yielded a centred distribution with a relative error less than 5 %. Excluding the analysis of light elements (B, C, O, N, F) improved the relative error to around 2 %
Ettringite dependace in thaumasite formation
Authors: Chinchón-Payá S , Aguado A , Chinchón S
Published: August 2020

Thaumasite has been synthetized with and without ettringite in the reaction medium. The compositions of solids have been analyzed over time by means of X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM-EDX) in order to check the relation between ettringite and thaumasite. The results indicate that in the synthesis in absence of ettringite, the thaumasite appears at 6 months. By contrast, in the synthesis with presence of ettringite, at 7 days much of the ettringite has become thaumasite and at 2 months ettringite has disappeared and only thaumasite is detected. The results obtained at the end of two years experience, using the Rietveld method, show that thaumasite forms from ettringite by substitution of aluminum with silicon.
The Impact of Legalized Abortion on Crime over the Last Two Decades
Authors: Donohue John J , Levitt Steven
Published: August 2020

Donohue and Levitt (2001) presented evidence that the legalization of abortion in the early 1970s played an important role in the crime drop of the 1990s. That paper concluded with a strong out-of-sample prediction regarding the next two decades: “When a steady state is reached roughly twenty years from now, the impact of abortion will be roughly twice as great as the impact felt so far. Our results suggest that all else equal, legalized abortion will account for persistent declines of 1% a year in crime over the next two decades.” Estimating parallel specifications to the original paper, but using the seventeen years of data generated after that paper was written, we find strong support for the prediction and the broad hypothesis, while illuminating some previously unrecognized patterns of crime and arrests. We estimate that overall crime fell 17.5% from 1998 to 2014 due to legalized abortion—a decline of 1% per year. From 1991 to 2014, the violent and property crime rates each fell by 50%. Legalized abortion is estimated to have reduced violent crime by 47% and property crime by 33% over this period, and thus can explain most of the observed crime decline.
A new genetic locus for self-compatibility in the outcrossing grass species perennial ryegrass (Lolium perenne)
Authors: Slatter Lucy M , Barth Susanne , Manzanares Chloe , Velmurugan Janaki , Place Iain , Thorogood Daniel
Published: August 2020

Background

Self-incompatibility (SI) is a physiological mechanism that many flowering plants employ to prevent self-fertilization and maintain heterozygosity. In the grass family this is known to be controlled by a two locus (S-Z) system; however, the SI system is intrinsically leaky. Modifier genes of both the S and Z loci and a further locus, T, are known to override SI leading to self-fertilization and self-seed production. This has implications for the ecological and evolutionary success as well as the commercial breeding of grasses. Here we report a study where the genetic control of self-compatibility (SC) was determined from the results of self-pollinating an F2 population of perennial ryegrass from two independently derived inbred lines produced by single-seed descent.

Methods

In vitro self-pollinations of 73 fertile plants were analysed. A genetic association analysis was made with a panel of 1863 single-nucleotide polymorphism (SNP) markers, generated through genotype-by-sequencing methodology. Markers were placed on a recombination map of seven linkage groups (LGs) created using Joinmap v.5. The seed set on self- and open-pollinated inflorescences was determined on 143 plants, including the 73 plants analysed for self-pollination response.

Key Results

Self-pollinations revealed a bimodal distribution of percentage SC with peaks at 50 and 100 %. A single quantitative trait locus (QTL) was identified with peak association for marker 6S14665z17875_11873 that mapped to LG 6. Peak position was associated with maximum marker segregation distortion. The self-compatible plants were equally fecund after self- and open pollination.

Conclusions

This is the first report in the Poaceae family of an SC locus located on LG 6. This new SC QTL discovery, as well as indicating the complex nature of the pollen–stigma recognition process and its evolutionary significance, provides an additional source of SC for breeding perennial ryegrass.