bluuebunny/crossref_metadata_2025 huggingface dataset:
Peningkatan Kapasitas UMKM Kabupaten Gorontalo Utara dalam Meningkatkan Penjualan Melalui Strategi Pemasaran Digital
Authors: Yusuf Rampi , Lahinta Agus
Published: January 2021

The Covid-19 virus pandemic has destroyed the most important side of the economy, namely supply and demand. From the supply side, many Micro, Small and Medium Enterprises (MSMEs) have experienced a reduction in activity due to the policy of limiting social interaction which has resulted in the cessation of the production process, and from the demand side, reduced demand for goods and services has resulted in many MSMEs unable to maximize profits. One of the economic recovery strategies is to connect with the digital ecosystem, by digitizing the market so that business actors can continue to carry out their business activities even in the midst of the Covid-19 pandemic. The goal to be achieved in this activity is to increase the capacity of MSMEs and Hutakalo village people and their sales through digital marketing strategies. The methods used to achieve these goals are socialization and training. Through outreach activities, MSMEs together with the people of Hutakalo village were given general material on digital marketing strategies and how the Hutakalo village's MSMEs and communities were able to increase the value of their business sales by using digital marketing strategies. Meanwhile, training activities are carried out to improve the skills of MSMEs and Hutakalo villagers in using the Marketplace application to market their business products, which is supported by the ability to make product photos to make them look attractive to be marketed.
Perilaku Ibu Terhadap Pertumbuhan Balita Dalam Permasalahan Stunting Dan Pencegahannya Di Desa Torosiaje Jaya
Authors: Husain Rustam I. , Umar Masri Kudrat , Lamatenggo Nina
Published: January 2021

The growth process experienced by toddlers is a cumulative result since the toddler was born. From various studies on stunting and existing literature it is known that in addition to infection, stunting is also associated with nutritional deficiencies (micronutrients and macronutrients). There are several nutrients related to stunting such as protein, iron, zinc, calcium, and vitamins D, A and C. at the family level, especially for poor families, low family access to basic health services, and disparities between provinces that need to be addressed specifically for problems in vulnerable areas.6,9,10 Stunting is a sensitive indicator for poor socioeconomic conditions and predictors for long-term morbidity and mortality. Stunting in early childhood is reversible. 11
A Fully Convolutional Neural Network-based Regression Approach for Effective Chemical Composition Analysis Using Near-infrared Spectroscopy in Cloud
Authors: Jiang Daiyu , Hu Gang , Qi Guanqiu , Mazur Neal
Published: January 2021

As one chemical composition, nicotine content has an important influence on the quality of tobacco leaves. Rapid and non-destructive quantitative analysis of nicotine is an important task in the tobacco industry. Near-infrared (NIR) spectroscopy as an effective chemical-composition analysis technique has been widely used. In this paper, we propose a one-dimensional Fully Convolutional Network (1D-FCN) model to quantitatively analyze the nicotine composition of tobacco leaves using NIRspectroscopy data in a cloud environment. This 1D-FCN model uses one-dimension convolution layers to directly extract the complex features from sequential spectroscopy data. It consists of five convolutional layers and two full connection layers with the max-pooling layer replaced by a convolutional layer to avoid information loss.Cloud computing techniques are used to solve the increasing requests of large-size data analysis and implement data sharing and accessing.Experimental results show that the proposed 1D-FCN model can effectively extract the complex characteristics inside the spectrum and more accurately predict the nicotine volumes in tobacco leaves than other approaches. This research provides a deep learning foundation for quantitative analysis of NIR spectra data in the tobacco industry.
Menopozal Semptomların Yönetiminde Egzersiz Uygulamasının Rolü
Authors: BÜYÜKKAPLAN Büşra , HÖBEK AKARSU Rukiye , ŞAHAN Özlem , AKARSU Gökhan Doğukan
Published: January 2021

Kadın hayatında önemli bir yeri olan menopozal dönem; overlerde hormon azalması sonucu ortaya çıkan ve üreme yeteneğinin kaybolduğu bir dönemdir.Bu hormonal değişikliklere bağlı olarak kadınlar sıcak basması, gece terlemesi, kas ve eklem ağrısı, psikolojik olarak ise uykusuzluk, huzursuzluk, sinirlilik, baş ağrısı, sıkıntı hissi ve unutkanlık gibi semptomlar yaşamaktadırlar. Bu semptomlar kadın hayatını olumsuz bir şekilde etkilemektedir. Bu dönemde yapılan egzersiz; menopoz semptomlarını hafifletmeye, bu dönemde ortaya çıkan problemleri azaltmaya yardımcı olmaktadır.Bu nedenle menopozal dönemde yapılan egzersiz kadınların yaşam kalitesini artırmak ve semptomlarla baş edebilmek açısından kadınlar için önemlidir.
Apresentação - Dossiê - História das Diversões: algumas possibilidades investigativas
Authors: Maciel da Silva Igor , Teixeira Soutto Mayor Sarah , Dias Cleber
Published: January 2021

Apresentação do Dossiê: História das Diversões.
CHANGE DETECTION AND GIS-BASED FUZZY AHP TO EVALUATE THE DEGRADATION AND RECLAMATION LAND OF TIKRIT CITY, IRAQ
Authors: Shareef Muntadher Aidi , Ameen Mohammed Hashim , Ajaj Qayssar Mahmood
Published: January 2021

LULC factors in Tikrit city (Iraq) and the neighboring municipalities are studied among 1989, 2002 and 2015 using various techniques of remote sensing, geographical information system (GIS), and fuzzy analytical hierarchy process (FAHP). Satellite imagery with GIS helped to assess the standard LULC changes in the long term period. FAHP permitted estimating the importance of various LULC by determination of the suitable weight for used factors and then producing the evaluating models. Using different techniques, two models were created (1) to estimate the degradation of the land (2) is generated to determine the reclamation of the area. The finding reveals that the a overall accuracy of 97.0939%, 98.9199% and 99.5817% or 1989, 2002 and 2015 respectively. The outcomes also revealed that urban, vegetation, and water features area are developed in the long term (1989–2015) about 4.35%, 4.28%, and 1.49%, respectively, while barren area is reduced about 5.57%.The degradation map index showed that the lands strongly debased are these converted from vegetation to barren, followed by moderate to high these changed from water areas to urban, while moderate degradation is noticed of urban transformed to barren soil. Contrary, the reclamation map index illustrated that the lands are powerfully transformed from barren to the vegetation and followed by those converted from barren to the water, while barren transformed to the urban is marked as moderate reclamation. The transformation from urban to vegetation or water was classified as the low and deficient class to evaluate the area. The study is also revealed that the integration of remote sensing and GIS produces a successful method for LULC monitoring and managing the environment.
A New Method to Estimate Halo CME Mass Using Synthetic CMEs Based on a Full Ice Cream Cone Model
Authors: Na Hyeonock , Moon Yong-Jae , Lee Jin-Yi , Cho Il-Hyun
Published: January 2021

In this study, we suggest a new method to estimate the mass of a halo coronal mass ejection (CME) using synthetic CMEs. For this, we generate synthetic CMEs based on two assumptions: (1) the CME structure is a full ice cream cone, and (2) the CME electron number density follows a power-law distribution (ρ
cme = ρ
0
r
−n
). The power-law exponent n is obtained by minimizing the rms error between the electron number density distributions of an observed CME and the corresponding synthetic CME at a position angle of the CME leading edge. By applying this methodology to 56 halo CMEs, we estimate two kinds of synthetic CME masses. One is a synthetic CME mass that considers only the observed CME region (M
cme1), the other is a synthetic CME mass that includes both the observed CME region and the occulted area (M
cme2). From these two cases, we derive conversion factors that are the ratio of a synthetic CME mass to an observed CME mass. The conversion factor for M
cme1 ranges from 1.4 to 3.0 and its average is 2.0. For M
cme2, the factor ranges from 1.8 to 5.0 with an average of 3.0. These results imply that the observed halo CME mass can be underestimated by about 2 times when we consider the observed CME region, and about 3 times when we consider the region including the occulted area. Interestingly these conversion factors have a very strong negative correlation with angular widths of halo CMEs.
Metal-THINGS: On the Metallicity and Ionization of ULX Sources in NGC 925
Authors: Lara-López Maritza A. , Zinchenko Igor A. , Pilyugin Leonid S. , Gunawardhana Madusha L. P. , López-Cruz Omar , O’Sullivan Shane P. , Feltre Anna , Rosado Margarita , Sánchez-Cruces Mónica , Chevallard Jacopo , De Rossi Maria Emilia , Dib Sami , Fritz Jacopo , Fuentes-Carrera Isaura , Garduño Luis E. , Ibar Eduardo
Published: January 2021

We present an analysis of the optical properties of three Ultra Luminous X-ray (ULX) sources identified in NGC 925. We use Integral field unit data from the George Mitchel spectrograph in the context of the Metal-THINGS survey. The optical properties for ULX-1 and ULX-3 are presented, while the spaxel associated with ULX-2 had a low S/N, which prevented its analysis. We also report the kinematics and dimensions of the optical nebula associated with each ULX using ancillary data from the PUMA Fabry–Perot spectrograph. A BPT analysis demonstrates that most spaxels in NGC 925 are dominated by star-forming regions, including those associated with ULX-1 and ULX-3. Using the resolved gas-phase metallicities, a negative metallicity gradient is found, consistent with previous results for spiral galaxies, while the ionization parameter tends to increase radially throughout the galaxy. Interestingly, ULX-1 shows a very low gas metallicity for its galactocentric distance, identified by two independent methods, while exhibiting a typical ionization. We find that such low gas metallicity is best explained in the context of the high-mass X-ray binary population, where the low-metallicity environment favors active Roche lobe overflows that can drive much higher accretion rates. An alternative scenario invoking accretion of a low-mass galaxy is not supported by the data in this region. Finally, ULX-3 shows both a high metallicity and ionization parameter, which is consistent with the progenitor being a highly accreting neutron star within an evolved stellar population region.
Flare Activity and Magnetic Feature Analysis of the Flare Stars. II. Subgiant Branch
Authors: Goodarzi Hadis , Mehrabi Ahmad , G. Khosroshahi Habib , He Han
Published: January 2021

We present an investigation of the magnetic activity and flare characteristics of the subgiant stars mostly from F and G spectral types and compare the results with the main-sequence (MS) stars. The light curve of 352 stars on the subgiant branch (SGB) from the Kepler mission is analyzed in order to infer stability, relative coverage, and contrast of the magnetic structures and also flare properties using three flare indexes. The results show the following. (i) Relative coverage and contrast of the magnetic features along with rate, power, and magnitude of flares increase on the SGB due to the deepening of the convective zone and more vigorous magnetic field production. (ii) Magnetic activity of the F- and G-type stars on the SGB does not show dependency on the rotation rate and does not obey the saturation regime. This is the opposite of what we saw for the MS, in which the G-, K-, and M-type stars show clear dependency on the Rossby number. (iii) The positive relationship between the magnetic features’ stability and their relative coverage and contrast remains true on the SGB; though, it has a lower dependency coefficient in comparison with the MS. (iv) Magnetic proxies and flare indexes of the SGB stars increase with increasing relative mass of the convective zone.
Disks as Inhomogeneous, Anisotropic Gaussian Random Fields
Authors: Lee Daeyoung , Gammie Charles F.
Published: January 2021

We model astrophysical disk surface brightness fluctuations as an inhomogeneous, anisotropic, time-dependent Gaussian random field. The field locally obeys the stochastic partial differential equation of a Matérn field, which has a power spectrum that is flat at large scales and falls off as a power law at small scales. We provide a series of pedagogical examples and along the way provide a convenient parameterization for the local covariance. We then consider two applications to disks. In the first we generate an animation of a disk. In the second, by integrating over an animation of a disk, we generate synthetic light curves and show that the high frequency slope of the resulting power spectrum depends on the local covariance model. We finish with a summary and a brief discussion of other possible astrophysical applications.
Extension of TOPSIS method under intuitionistic fuzzy hypersoft environment based on correlation coefficient and aggregation operators to solve decision making problem
Authors: Zulqarnain Rana Muhammad ,   School of Mathematics, Northwest University Xi'an, China, Xin Xiao Long , Saeed Muhammad ,   School of Science, Xi'an Polytechnic University, Xi'an 710048, China,   Department of Mathematics, School of Science, University of Management and Technology, Lahore, Pakistan
Published: January 2021

Intuitionistic fuzzy hypersoft set is an extension of the intuitionistic fuzzy soft set used to express insufficient evaluation, uncertainty, and anxiety in decision-making. It is a new technique to realize computational intelligence and decision-making under uncertain conditions. The intuitionistic fuzzy hypersoft set can deal with uncertain and fuzzy information more effectively. The concepts and properties of the correlation coefficient and the weighted correlation coefficient of the intuitionistic fuzzy hypersoft sets are proposed in the following research. A prioritization technique for order preference by similarity to ideal solution (TOPSIS) based on correlation coefficients and weighted correlation coefficients is introduced under the intuitionistic fuzzy hypersoft sets. We also introduced aggregation operators, such as intuitionistic fuzzy hypersoft weighted average and intuitionistic fuzzy hypersoft weighted geometric operators. Based on the established TOPSIS method and aggregation operators, the decision-making algorithm is proposed under an intuitionistic fuzzy hypersoft environment to resolve uncertain and confusing information. A case study on decision-making difficulties proves the application of the proposed algorithm. Finally, a comparative analysis with the advantages, effectiveness, flexibility, and numerous existing studies demonstrates this method's effectiveness.
Crystal Orientation Relationships among Acicular Ferrite, Oxide and the Austenite Matrix in a Steel Weld Metal
Authors: Nako Hidenori , Zhang Yong Jie , Miyamoto Goro , Furuhara Tadashi
Published: January 2021

Acicular ferrite (AFα) formed on oxide particles in steel weld metals has a positive effect on toughness at low temperature. Good lattice coherency between AFα and oxide is one of the proposed reasons for promotion of AFα formation. Lattice coherency is affected by crystal structure of oxide and crystal orientation relationship (OR) between oxide and AFα. In the present study, ORs among AFα, oxide and γFe are investigated in a low carbon steel weld metal. Cube-cube (C-C) OR is observed between γFe and the oxide. It is probable that the oxide liquefied at high temperature, and then crystalized having the C-C OR with the surrounding γFe during cooling in welding process. Near Kurdjumov-Sachs (K-S) and near Baker-Nutting (B-N) ORs are observed between γFe/AFα and oxide/AFα, respectively. The misorientation from the B-N OR is larger than that from the K-S OR just after nucleation of AFα. This implies that AFα forms satisfying a near K-S OR with γFe essentially. It is supposed that formation of both the C-C (γFe/oxide) and near K-S (AFα/γ) ORs results in apparent formation of the near B-N OR between oxide and AFα.
Influence of Radial Shear Rolling Regimes on the Homogeneity of Structural-Phase State, Mechanical Properties and Fatigue of near β Titanium Alloy
Authors: Naydenkin Evgeny V. , Mishin Ivan P. , Ratochka Il'ya V. , Lykova Olga , Manisheva Anna I.
Published: January 2021

The studies showed that as a result of radial-shear rolling (RSR) in the temperature range of 850-650°C the formation of a quasi-globular ultrafine grain-subgrain structure with a size of structural elements of about 0.5-0.7 μm is observed in near β titanium alloy Ti-5Al-5V-5Mo-1Cr-1Fe. Subsequent annealing (aging) in the temperature range of 450°C for 5 hours leads to the decomposition of the β-phase matrix deformed during the rolling process with the formation of nanosized acicular precipitates of the martensitic α" phase along with finely dispersed inclusions of α phase particles preserved after rolling. The formation of such ultrafine-grained (UFG) structure leads to a significant (more than 25%) increase in the strength properties of the alloy compared to the initial state while maintaining sufficient ductility (~5%). Also obtained by the method UFG titanium alloy exhibits a high fatigue strength under very high cycle loading (fatigue strength based on 108 cycles exceeds 700 MPa).
Threshold Voltage Control for MONOS Nonvolatile Memory with High-k HfN/HfO2 Stacked Layers for Analog Memory Application
Authors: Ohmi Shun Ichiro , Pyo Jooyoung
Published: January 2021

In this paper, we have investigated the threshold voltage (VTH) control of metal-oxide-nitride-oxide-Si (MONOS) nonvolatile memory (NVM) with high-k HfN/HfO2 stacked layers for analog memory application. The Si surface atomically flattening was found to significantly improve the VTH controllability of the MONOS NVM with high-k HfN/HfO2 stacked layers. The multi-level-cell (MLC) operation by controlling the program voltage at the source and drain was demonstrated utilizing MONOS NVM with high-k HfN/HfO2 stacked layers.
In Situ Neutron Diffraction Measurement during Bainite Transformation and Accompanying Carbon Enrichment in Austenite at iMATERIA, J-PARC MLF
Authors: Onuki Yusuke , Hirano Takashi , Umemura Kazuki , Sato Shigeo , Tomida Toshiro
Published: January 2021

The authors have developed the in situ neutron diffraction technique focusing on bainite transformation during austempering. Thanks to the features of time-of-flight type neutron diffraction, textures, phase fractions and lattice parameters can be simultaneously measured at high temperature. In this paper, the design of experimental equipment and analytical approach are mainly described.
The Multiphase Micro- and Nanostructures of 0.2 and 0.4 C Direct-Quenched and Partitioned Steels
Authors: Pallaspuro Sakari , Miettunen Ilkka Herman , Aravindh S. Assa , Ghosh Sumit , Cao Wei , Somani Mahesh Chandra , Kömi Jukka I.
Published: January 2021

Quenching and partitioning produces advanced high-strength steels that utilise transformation-induced plasticity for improved strength and deformability. Microstructures of these steels consist mainly of tempered martensite and carbon-enriched retained austenite. A novel processing route of direct-quenching and partitioning (DQP) facilitates carbon partitioning from supersaturated martensite to untransformed austenite directly from the quench-stop temperature in a decelerated cooling that simulates slow cooling of a coiled strip. A major advantage of DQP steels is that they keep both the costs and emissions down by inexpensive alloying and energy-efficient processing. In this study, we investigate the microstructures of 0.2C and 0.4C laboratory hot-rolled DQP steels with comparison to a direct-quenched variant with high-resolution transmission electron microscopy as the main research technique. We show that the structures of DQP steels have frequent nanotwinned regions and can contain three different crystal structures with characteristic length scales ranging from few nm to ~200 nm. This is in remarkable contrast to the traditional lath-martensitic microstructure of the as-quenched material. Density functional theory calculations provide further insight into these findings with the calculated results of energetics, and show that carbon helps in stabilising the newly found omega phase. These results give further insight to the aspects that must be considered when assessing their effect on essential mechanical properties like strain hardening and toughness.
The Occurrence of a Peripheral Coarse Grain Zone (PCGZ) in Extruded Bars of AA 7108
Authors: de Souza Saul Hissaci , Plaut Ronald Lesley , Lima Nelson B. , de Oliveira Rene Ramos , Padilha Angelo Fernando
Published: January 2021

Industrial-scale extruded profiles of AA 7108 with a rectangular section (25.60 mm x 15.95 mm) were used in this investigation. Some complementary microstructural analysis techniques, such as polarized light microscopy, EBSD (Electron Backscatter Diffraction) and X-ray diffraction were used to characterize the microstructure, focusing on the PCG zone. It was observed that the extruded profiles presented a totally recrystallized microstructure and a 300 μm layer of peripheral coarse grains. Additionally, the results showed that the PCGZ predominant grain orientation {311} <110> differs from the texture below the PCGZ (Goss and Cube components).
Application of Image Analysis Method Combined with Microhardness Measurement to Determine Phase Fractions
Authors: Pohjonen Aarne , Koskenniska Sami , Uusitalo Juha , Nyo Tun , Larkiola Jari , Kömi Jukka I.
Published: January 2021

We have determined different phase fractions from microscopy images using semi-automated image analysis fitting technique, and in addition we have classified each phase according to its hardness. The distribution of grayscale pixels of different phases is first characterised separately for each phase, which are sampled from the microscope image. After this the distributions of the separate phases are fitted to give the corresponding distribution of the whole image. The microhardness measurement provides reliability on the classification of the different phases to ferrite, bainite or martensite. In addition to describing the applied techniques in detail, we present the results obtained from the analysis for one steel subjected to isothermal holding experiments at different temperatures.
Microstructure of Al-2.5Fe Binary Alloy Fabricated by Laser Powder Bed Fusion
Authors: Qi Xing , Takata Naoki , Suzuki Asuka , Kobashi Makoto , Kato Masaki
Published: January 2021

In the present study, microstructural and crystallographic features of an Al-Fe binary alloy with a near eutectic composition (Al-2.5wt%Fe) fabricated by laser powder bed fusion (LPBF) process were examined. The LPBF processing for the Al-Fe alloy powder was conducted at room temperature using a 3D Systems ProX 200 operating at a laser power of 204 W and a laser scan speed of 0.6 m/s and 0.8 m/s to fabricate cube samples with high relative density above 99 %. The fabricated sample exhibited characteristic microstructure consisting of a number of melt pools in which the regions had locally melted and rapidly solidified by laser irradiation during the LPBF process. Numerous fine particles of Al-Fe intermetallics with a mean size below 100 nm were found within the α-Al matrix in the observed melt pools, whereas relatively coarsened particles were localized around melt pool boundaries. Electron backscatter diffraction (EBSD) analyses revealed a number of columnar a-Al grains with a mean size of approximately 10 μm. The LPBF-fabricated Al-Fe alloy exhibits a high hardness of approximately 90 HV, which is more than twice higher than the conventionally casted Al-Fe alloy.
Mechanism of Void Formation during Brazing of Ni Paste Brazing Filler Metal
Authors: Sakai Mana , Sasaki Tatsuya , Miyazawa Yasuyuki
Published: January 2021

Automobiles are equipped with EGR (Exhaust Gas Recirculation) coolers to improve fuel economy and exhaust gas suppression performance. Inside the EGR cooler, the moisture in the gas is condensed by cooling the hot exhaust gas. This condensed water is highly corrosive because sulfur oxides dissolve. Therefore, stainless steel and Ni-based brazing metal having excellent corrosion resistance are used for the EGR cooler.Until now, stainless steel has been brazed under a vacuum atmosphere. However, there are increasing opportunities to braze stainless steel in an inert atmosphere gas at atmosphere for cost reduction and mass production. In this case, a paste-type brazing filler metal consisted of a powder brazing filler metal and a binder is used. As is well known, a debinding process that volatilizes the binder is needed. From previous research in this laboratory, it is clarified that the binder causes voids. In addition, it is said that the size and location of voids generated at the brazed joint affect the product performance. On the other hand, the detailed investigation about the influence which the installation position of a paste type brazing filler metal on the void formation process has not yet been made. Therefore, in this study, the arrangement method and influence on heating rate and debinder temperature on void formation were investigated by X-ray CT.
Effect of Stacking Fault Energy and Solute Atoms on Microstructural Evolutions of FCC Metals Processed by Severe Plastic Deformation
Authors: Asano Mayu , Yuasa Motohiro , Miyamoto Hiroyuki
Published: January 2021

Pure copper, pure silver, Cu-6.8at%Al, Cu-1at%Mn and Cu-5at%Ni (stacking fault energies (SFEs) are about 41, 22, 23, 43 and 105mJ/m2, respectively) were processed by equal channel angular pressing (ECAP) at the same homologous temperatures to investigate the effect of SFE and solute atoms on microstructural evolutions. The final grain size of Cu-6.8at%Al after eight passes of ECAP was the smallest followed by that of Cu-1at%Mn with little difference. The former alloy reaches saturation for grain size and grain boundary misorientation in early passes of ECAP while the latter continues decreasing even after eight passes. The role of shear bands and deformation twins is predominant for grain fragmentation in the early stage for Cu-6.8at%Al and Ag with low SFE while evolution from cell walls to grain boundaries is main mechanism for Cu, Cu-1at%Mn and Cu-5at%Ni with medium or high SFE. Solute Mn atom of Cu-Mn with high atomic size misfit and may suppress the dynamic recovery which transforms cell walls to grain boundaries, and allow accumulation of higher dislocations and reduction of cell size to smaller scales.
Friction and Wear Response of a Hard-Anodized AA6082
Authors: Santecchia Eleonora , Cabibbo Marcello , Hamouda Abdel Magid S. , Musharavati Farayi , Popelka Anton , Spigarelli Stefano
Published: January 2021

The properties of anodized aluminum, and wear resistance in particular, are of high interest for the scientific community. In this study, discs of AA6082 were subjected to a peculiar hard anodizing process leading to anodized samples having different thicknesses. In order to investigate the wear mechanism of samples, unidirectional tribological tests were performed against alumina balls (corundum) under different loading conditions. Surface and microstructure of all the samples were characterized before and after the tribological tests, using different characterization techniques. The tribological tests showed remarkable differences in the friction coefficient and wear behavior of the anodized AA6082 samples, related to the microstructure modifications and to the specific applied sliding conditions.
Fatigue Behavior of Age-Hardening Cu-6Ni-1.5Si Alloys with Different Grain Sizes
Authors: Goto Masahiro , Yamamoto Takaei , Han S.Z. , Kitamura J. , Ahn J.H. , Lim S.H. , Lee S.J. , Utsunomiya T. , Lee J.
Published: January 2021

On the thermomechanical treatments of Cu-Ni-Si alloy, cold-rolling (CR) before solution heat treatment (SHT) is commonly conducted to eliminate defects in a casting slab. In addition, a rolling is applied to reduce/adjust the thickness of casting slab before SHT. In a heavily deformed microstructure by CR, on the other hand, grain growth during a heating in SHT is likely to occur as the result of recrystallization. In general, tensile strength and fatigue strength tend to decrease with an increase in the grain size. However, the effect of difference in grain sizes produced by with and without CR before SHT on the fatigue strength is unclear. In the present study, fatigue tests of Cu-6Ni-Si alloy smooth specimens with a grain fabricated through different thermomechanical processes were conducted. The fatigue behavior of Cu-Ni-Si alloy was discussed.
Metal-Free and Carbon-Free Flexible Self-Supporting Thin Film Electrodes
Authors: Benbalit Chahrazad , Frau Eleonora , Scheuber Olivera , Schintke Silvia
Published: January 2021

Conductive polymers are promising for application in the medical and sport sectors, e.g. for thin wearable health monitoring systems. While many today’s electrodes contain either carbon or metals as electrically conductive filler materials, product design manufacturing has an increasing interest in the development of metal free and carbon free, purely polymer based electrode materials. While conducting polymers have generally rather low electrical conductivities compared to metals or carbon, they offer broad options for industrial processing, as well as for dedicated adjustments of final product properties and design aspect, such as colour, water repellence, or mechanical flexibility in addition to their electrical properties. The development of electrically conducting polymer blends, based on conductive polymers is thus timely and of high importance for the design of new attractive flexible electrodes. We have developed material formulation and processing techniques for the fabrication of self-supporting thin film electrodes based on polyaniline (PANI) and polyvinylidene fluoride (PVDF) blends. Electrical four-point probing was used to evaluate the electrode conductivity for different processing and fabrication techniques. Optical microscopy and atomic force microscopy measurements corroborate the observed electrical conductivity obtained even at low PANI concentrations revealing the nanoscale material distribution within the blends. Our self-supporting thin film electrodes are flexible, smooth, and water repellent and were furthermore successfully tested under bending and upon storage over a period of several months. This opens new perspectives for the design of metal free and carbon free flexible electrodes for medical, health, and sports applications.
Fabrication of Silver-Nanowire/PVDF Self-Supporting Thin Flexible Electrode Membranes
Authors: Benbalit Chahrazad , Scheuber Olivera , Frau Eleonora , Schintke Silvia
Published: January 2021

Flexible electrodes play an increasing role for medical applications, such as ECG (electrocardiography) or TENS (Transcutaneous electrical nerve stimulation) due to comfort in use and thus their suitability for health monitoring under movement and during sport. Polymers, such as polyvinylidene fluoride (PVDF), are promising for the development of fabrication methods and materials for such application cases, as stable flexible thin polymer membranes can be produced at large scale. We have compared different up-scalable fabrication techniques of thin electrode membranes based on PVDF as a function of silver nanowire concentration, using electrospinning, spincoating, and drop-casting techniques. The produced thin films and membranes and thin films were investigated by electrical four-point probing, optical microscopy, atomic force microscopy, as well as by stability tests under bending, and water exposure. We show, that a combination of electrospinning and spin-coating presents a reliable method for the fabrication of AgNW-PVDF based flexible nanofiber membrane electrodes (NMEs). Our nanofiber membrane electrodes (NMEs) exhibit a 10 times lower sheet resistance than AgNW-PVDF thin film electrodes (TFEs) produced for comparisons by a combination of spincoating and drop-casting using the same amounts of AgNWs. Upon immersion in water for up to 48 hours, we do not detect any nanowire release or decomposition of the fabricated electrodes, which is promising in view of application of the AgNW-PVDF composite electrodes in humid environment.
Residual Stress in Automotive Powertrains: Methods and Analyses
Authors: Sediako Dimitry , Stroh Joshua , Kianfar Sina
Published: January 2021

Residual stress is one of the main reasons for failure of automotive cylinder blocks and engine heads. These failures are typically associated with in-service distortion or cracking occurring in engines during operation cycles. The problem becomes more pronounced for engines that are running at elevated operating pressures and temperatures, limiting R&D options in developing and implementing higher-efficiency engines. New aluminum alloys and manufacturing methods have been introduced with varying degree of success, in many cases affected by the stress magnitudes and stress distribution in the component. Therefore, active research is ongoing internationally on finding the most reliable methods of stress analysis as a basis for developing efficient methods for stress mitigation. The current study presents a comparison between two experimental strain measurements techniques: a destructive method that is based on application of strain gauge sensors, and a non-destructive method using neutron diffraction. The results indicate that although the strain gauge method provides an indication of the nature (i.e. compression or tension) of strain within a component, this method should primarily be used for surface measurements and qualitative analyses only. Neutron diffraction remains the superior technique for strain analysis, particularly for engineering components with complex geometries. The results from this study provide the transportation industry with a more comprehensive understanding of the efficacy of utilizing strain gauge sensors, neutron diffraction or finite element modelling for measuring the residual strain in cast components. The results will help manufacturers to develop the next generation of powertrain systems with increased efficiency and improved performance.
Industrial Fe-Simulation of Roughing Using an Automatic Solver Shifting Technique
Authors: Seppälä Oskari , Ilmola Joonas , Larkiola Jari
Published: January 2021

Roughing has been simulated with the Finite element software AbaqusTM to replicate an industrial-scale process. The model has been made to be as close as possible to its real counterpart. For this purpose, an automated controlling logic has been created to simulate the multiple passes as well as inter-pass times for roughing. Simulating multiple passes with FEM is computationally very demanding, so new methods to reduce computing times are worth considering. During a roll pass an explicit solver is necessary due to high deformation amounts and rates. An explicit solver is tied to a very small time increment, so it takes a long time. On the other hand, inter-pass periods do not include any deformation or roller contact, so an implicit solver is quite capable of computing this portion of the simulation. An implicit solver can speed up the time increment considerably when compared to the explicit solver, so using it potentially saves a significant amount of computing time. Unfortunately, Abaqus does not include any methods to change the solver during a single simulation. Instead it is possible to communicate between the two solver types by manually importing data from a completed simulation to a new simulation model. A new method to change solvers automatically using a self-made Python code is proposed in this paper.
Deformation Behavior of Single Particle Cold Spray Ti-6Al-4V Splats
Authors: Sharma Mala M. , Judd Kiran G. , Schreiber Jeremy M. , Eden Timothy J.
Published: January 2021

The rapid development of cold spray technology has made it a viable option to repair and remanufacture damaged components as well as to create novel materials for biomedical applications. One of the most influential parameters of this distinctive process is the deposition velocity, which ultimately controls the degree of material deformation and material adhesion. Although the majority of materials can be successfully deposited at relative low deposition velocity (<700m/s), this is not representative of Ti alloys which have high yield strength. The amount of deformation and resultant properties of the coating are related to the velocity, temperature, and tensile strength of the particles. The ability to predict the deformation and resultant properties helps in developing process parameters and tailoring coatings to get the desired properties. In the current study, the particle deformation behavior and bonding with the substrate was investigated over a range of impact conditions. The effects of deposition velocity, gas temperature, gas pressure and nozzle stand-off distance were studied using cold sprayed splats of spherical Ti-6Al-4V powder deposited on to 316 SS substrate utilizing helium as a carrier gas. Finite element modeling of the impacted particles was conducted using Johnson-Cook high-strain-rate properties in a Lagrangian analysis to predict the overall deformation and estimated stress state of the impacted particles. Particle temperature due to impact was also predicted. Overall predictions were in good agreement with experimental results. Optical microscopy, scanning electron microscopy (SEM) and focused ion beam (FIB) were used to identify three distinct regions within the impact morphologies; these include the initial impact region, the jetting region, and the upper splat region.
Properties of Alumina Coatings Deposited by Detonation Spraying
Authors: Ulianitsky Vladimir , Shtertser Alexandr , Batraev Igor , Smurov Igor
Published: January 2021

Coatings deposited by detonation spraying equipment CCDS2000 using alumina powder are studied. CCDS2000 is characterized by a computer control system, robot compatible spraying unit (gun barrel), a portable chiller, two powder feeders, and other peculiar properties. This installation allows to deposit coatings on complex shape surfaces and thin-walled parts under optimal conditions. Studies of the coating properties included measurements of coating microstructure, porosity, microhardness, adhesion, cohesion, abrasive and erosive wear, and dielectric properties (specific resistivity and dielectric strength). The detonation sprayed coatings have an adhesion of 60-70 MPa, cohesion of 100 MPa, microhardness of 1500 HV100, porosity of about 1% (measured on microsections of coatings using OLYMPUS Stream Image Analysis software). Impregnation of coatings with silicone oil showed that the real open porosity of coatings is up to 6%. Dielectric strength of the ceramic layer with the thickness of 200 μm exceeds 30 kV/mm. Specific resistivity depends on atmospheric humidity and when the relative humidity is less than 60%, the specific resistivity is greater than 1013 Ω·cm.
Effect of Silicon Content on the Decomposition of Austenite in 0.4C Steel during Quenching and Partitioning Treatment
Authors: Miettunen Ilkka Herman , Ghosh Sumit , Somani Mahesh Chandra , Pallaspuro Sakari , Porter David A. , Kömi Jukka I.
Published: January 2021

Although quenched and partitioned (Q&P) steels are traditionally alloyed with Si, its precise role on microstructural mechanisms occurring during the partitioning process is not thoroughly investigated. In this study, a systematic investigation has been carried out to reveal the influence of Si on austenite decomposition, phase transformation and carbide precipitation during Q&P treatment. Using a Gleeble thermomechanical simulator, three medium carbon steels with varying Si contents (0.25, 0.70 and 1.5 wt.%) were hot-rolled, reaustenitized, quenched into the Ms -Mf range, retaining about 20% austenite at the quench-stop temperature (TQ), and held for 1000 seconds above TQ in the temperature range of 200-300°C in order to better understand the mechanisms operating during partitioning. Dilatometric measurements combined with microstructural characterization using SEM-EBSD, TEM, and XRD clearly revealed the occurrence of various mechanisms. The effect of partitioning temperature/time on the hardness of the Q&P samples was correlated with the microstructural features. Steel containing low Si content (0.25%) was incapable of promoting carbon enrichment of austenite during partitioning, leading to its continuous decomposition into isothermal martensite and/or bainite without any detectable austenite retained even holding at 300°C. In comparison, 1.5% Si content promoted retention of about 19% austenite under similar Q&P conditions. Small fractions of bainite and high-carbon martensite formed during final cooling in both steels after partitioning at 200°C. Moreover, carbide precipitation was strongly retarded by high Si content.
Development and Characterization of New Ti-25Ta-Zr Alloys for Biomedical Applications
Authors: Kuroda Pedro Akira Bazaglia , Quadros Fernanda de Freitas , Nascimento Mycaela Vieira , Grandini Carlos Roberto
Published: January 2021

This paper deals with the study of the development, structural and microstructural characterization and, selected mechanical properties of Ti-25Ta-50Zr alloy for biomedical applications. The alloy was melted in an arc furnace and various solution heat treatments were performed to analyze the influence of the temperature and time on the structure, microstructure, microhardness and elastic modulus of the samples. The structural and microstructural results, obtained by X-ray diffraction and microscopy techniques, showed that the solution heat treatment performed at high temperatures induces the formation of the β phase, while solution heat treatment performed at low temperatures induces the formation of the α” and ω metastable phases. Regarding the effect of time, samples subjected to heat treatment for 6 hours have only the β phase, indicating that lengthy treatments suppress the α” phase. Regarding the hardness and elastic modulus, the alloy with the α” and ω phases, after treatment performed at a temperature of 500 °C, has a high hardness value and elastic modulus due to the presence of the ω phase that hardens and weakens alloys. The titanium alloys developed in this study have excellent mechanical properties results for use in the orthopedic area, better than many commercial materials such as cp-Ti, stainless steel and Co-Cr alloys.
High-Temperature Oxidation of AISI441 Ferritic Stainless Steel for Solid Oxide Fuel Cells
Authors: Spotorno Roberto
Published: January 2021

Several ferritic stainless steel grades are widely studied and used in solid oxide fuel cells (SOFCs) technology as interconnect materials. Their high-temperature oxidation behavior is interesting to evaluate their applicability at SOFCs operating conditions and to design degradation tests and models predicting the lifetime of a SOFC stack. In this work the AISI441 grade was oxidized in static air at 850°C to study its oxidation kinetic by weight gain measurements. It was found a parabolic growth with a rate constant of 9.42 x 10-14 g2cm-4s-1. Data calculated using the diffusion coefficients of the species involved in the oxidation process resulted in higher weight gain. Discrepancies between the measurements and the model were corrected taking into account the chromium volatilization.
The Effect of Ni Precursor Salts on Diatomite Supported Ni-Mg Catalysts in Methanation of CO2
Authors: Sun Chao , Krstic Jugoslav , Radonjic Vojkan , Stankovic Miroslav , da Costa Patrick
Published: January 2021

This study is aimed to investigate the effect of Ni precursor salts on the properties (textural, phase-structural, reducibility, and basicity), and catalytic performance of diatomite supported Ni-Mg catalyst in methanation of CO2. The NiMg/D-X catalysts derived from various nickel salts (X = S-sulfamate, N-nitrate or A-acetate) were synthesized by the precipitation-deposition (PD) method. The catalysts were characterized by N2-physisorption, XRD, TPR-H2, and TPD-CO2 techniques. The different catalytic activity (conversion) and selectivity, observed in CO2 methanation carried out under relatively mild conditions (atmospheric pressure; temperatures: 250-450 °C) are related and explained by the difference in textural properties, metallic Ni-crystallite size, reducibility, and basicity of studied catalysts. The results showed that catalyst derived from Ni-nitrate salt (NiMg/D-N) is more suitable for the preparation of efficient catalyst for CO2 methanation than its counterparts derived from sulfamate (NiMg/D-S) or acetate (NiMg/D-A) nickel salt. The NiMg/D-N catalyst showed the highest specific surface area and total basicity, and the best catalytic performance with CO2 conversion of 63.3 % and CH4 selectivity of 80.9 % at 450 °C.
Tensile Deformation of Si Single Crystals at High Temperatures
Authors: Suzuki Tubasa , Tanaka Masaki , Morikawa Tatsuya , Okuyama Yelm , Fujise Jun , Ono Toshiaki
Published: January 2021

Czochralski silicon single crystals were deformed in tensile tests along the direction at between 1173 K and 1373. Yield point phenomenon were observed in the specimens deformed at below 1273 K while continues yield was observed in the specimens deformed at above 1323 K. It is due to the effect of dislocation starvation in the used crystals. Work-hardening rates in stage II were consistent with those reported in fcc crystals such as copper. The onset of stage II was found to be active before the Schmid factor of the second slip system becomes larger than that of the primary slip system. Electron backscattered diffraction images indicated clear kink bands near grips and in the parallel portion. The kink bands were formed at the middle of stage I, which suggest that the formation of kink bands is a trigger of stage II.
In Situ Evaluation of the Joining Defects in a Pb-Free Soldered Joint
Authors: Tajima Hikaru , Nakamura Yuta , Miyazawa Yasuyuki , Tameda Hidenobu
Published: January 2021

Conventionally, brass has toughness more than other metals, so there is a concern about its poor machinability. Therefore, improvement of machinability was attempted by adding lead to brass. This brass called free cutting brass, typified by JIS C3771. This free-cutting brass is used for piping components and machine parts. There is a concern about elution of the lead into drinking water. Hence, Drinking Water Quality Standards Law has been amended and it restricts lead content in the free cutting brass. Therefore, lead-free free-cutting brass with no lead or minimized content of lead is required.Consequently, a lead-free free-cutting brass had been developed to improve in machinability such as JIS C6931 and JIS C6803 that are added Si and Bi instead of lead respectively. Lead was also used for the solder for joining among pure copper pipes and brass valves. That causes elution of lead from the solder into drinking water. For this reason, Lead-free solder such as Sn-Sb and Sn-Ag-Cu have been used.A fire torch technology often was used for soldering of brass. The purpose of this study is investigating soldering-ability and wettability of lead-free solder on lead-free free-cutting brass. Hence, we investigated the soldering ability of lead-free solders, Sn-5%Sb and Sn-3%Ag-0.5%Cu, for pure Cu and brass joints with nonuniform heating by hot plate.