bluuebunny/crossref_metadata_2025 huggingface dataset:
A Conical Beam Antenna Using a Monopole Wire and Rectangular Copper Probe with Four Parasitic Sleeves for UMTS/WLAN Applications
Authors: Nuangwongsa K , Wongsiritorn P , Sukkamat R , Phongcharoenpanich C , Pumpoung T
Published: August 2022

This paper aimed to present a wideband monopole antenna for base station applications of indoor reception for UMTS (B1) and WLAN (IEEE 802.11b) systems. The operating frequency was ranged from 1.92 GHz to 2.5 GHz. The proposed antenna was made up of a probe and four connecting parasitic sleeves from the upper copper circular patch to the ground. The rectangular probe structure technique was used to extend the frequency band and effectively improve the matching conditions. The results from simulation and measurement showed that the presented antenna had a proper matching impedance of |S11| (dB) lower than -10 dB in the frequency band from 1.71 GHz to 3.72 GHz and also from 1.58 GHz to 2.98 GHz, respectively. The percentage of bandwidth was 74.03% and 61.40%, respectively. The antenna had a conical radiation pattern. The simulated and measured gains were 2.93 dBi to 3.6 dBi and 2.58 dBi to 3.54 dBi, respectively.
Magneto-optical studies of kerosene based ferrofluid
Authors: Nimisha O K , Pradeesh Kannan , Mary A P Reena
Published: August 2022

Magnetic fluids are technologically important due to their tunable magnetic, electrical and optical properties. The magneto optical properties of ferrofluid have a major role for the development of optoelectronic devices. This paper represents the detailed analysis of kerosene based ferrofluid, their structure and magneto optical properties will be investigated. Iron oxide nanofluids are synthesised by a Co-precipitation method. The X-ray diffraction technique is used for structural characterization. The magneto optical property of the iron oxide nanofluid have been investigated by linear dichroism measurements. Individual magnetic particle’s intrinsic optical anisotropy or shape anisotropy create linear dichroism. The magnetic susceptibility of ferrofluid with different volume fractions is measured using Quincke’s method.
Improvement of Hybrid Energy Storage Wireless Charging System Performance and Efficiency
Authors: Liew H F , Chong K H , Fahmi M I , Ezanuddin A A M , Junaidah A M J , Norhanisa K
Published: August 2022

To reduce pollution due to the use of conventional fossil fuel, many transportations are going to be electrified, environmental-friendly and zero-emission energy. Among countries with the most electric vehicle user are United State, Norway, and China. About 100,000 of charging outlet for electric vehicle (EV) in United States had been installed to increase the market demand of electric vehicle. As an essential step, the introduction battery is used as the main energy storage for EV, but it weighs heavily and expensive in price as caused by the increased energy storage capacity and improved EV performance. Lifespan of the battery will reduce as it needs to provide high demand of current in acceleration. There is a possibility for the contact charging to cause short circuit during raining as some of the charging port is exposed at open area. The aim of this research is to design a hybrid energy storage system (HESS) of wireless charging system with charge monitor in EV application. The energy storage types chosen were three series 3.7 V, 2000 mAh at 18650 lithium-ion batteries and five series 2.7 V with 50 F ultracapacitors arranged in passive configuration. The system was designed and simulated with Simulink from MATLAB and Proteus 8 to analyse the HESS and the performance of the wireless charging system. The charging time and discharging time of HESS was estimated. The wireless charging system was designed with the output voltage range of 5 V to 13 V and the output current range of 0.5 A to 2.0 A.
Analysis of Non-Invasive Fingerprint Thickness Based Authentication Method Utilizing Near Infrared Spectroscopy
Authors: Tajul Ariffin Q A , Sulaiman N
Published: August 2022

Fingerprints are a popular method of biometric based authentication. However, methods currently in use are susceptible to being bypass through the use of forgeries of the fingerprint pattern. Measuring the epidermal thickness of the fingerprint is a solution to the issue, as there are no current ways for a third-party to precisely replicate the thickness measurements. Near-Infrared Diffused Reflectance (NIR-DR) spectroscopy is the proposed method of measuring fingerprint thickness. Reflectance reading is taken at 5 specific wavelength points to generate a simplified plot for comparison. Thickness measurement is gauged by calculationg change in reflectance percentage between the 800-900nm range. Data gathered showed variation in the reflectance spectra that was unique to each subject. Application for a fingerprint thickness-based authentication method is plausible but require additional research with a larger population sample and looking into the effects of age and skin colour for their effect on epidermal thickness.
Development of Machine Learning models using WEKA for Atmospheric Data
Authors: Venkata Ramana Moorthy P , Sarojamma B , Reddy S Venkatramana
Published: August 2022

There are number of Atmospheric variables such as rainfall, temperature, wind speed, humidity, visibility, Wind gust, Precipitation, etc. For learning covariance of machines by principles, practical and probabilistic approaches are made using Gaussian process. In this paper by taking visibility, time with date, temperature as independent or responding variables and wind speed as dependent or response variable, we fit Gaussian process model. K star is an instance based classifier that classifies the data. RBF network is used for data and is similar structure of Gaussian process but it uses clustering method with weight parameters. Additive regression classifies the variables by using Decision Stump. Decision Tree Regression improves the model by removing the decisions of the tree that are not important in classification. We fit different Waikato Environment for Knowledge Analysis (WEKA) models for atmospheric data and which model is the best based on RMSE values.
Boosting Algorithms to Identify Distributed Denial-of-Service Attacks
Authors: Kumar V , Kumar A , Garg S , Payyavula S R
Published: August 2022

In the current pandemic situation, much work became automated using Internet of Things (IoT) devices. The security of IoT devices is a major issue because they can easily be hacked by third parties. Attackers cause interruptions in vital ongoing operations through these hacked devices. Thus, the demand for an efficient attack identification system has increased in the last few years. The present research aims to identify modern distributed denial-of-service (DDoS) attacks. To provide a solution to the problem of DDoS attacks, an openly available dataset (CICDDoS 2019) has recently been introduced and implemented. The attacks currently occurring in the dataset were identified using two machine learning methods, i.e. the light gradient boosting method (LGBM) and extreme gradient boosting (XGBoost). These methods have been selected because of their superior prediction ability in high volumes of data in less time than other methods require. The accuracy achieved by LGBM and XGBoost were 94.88% and 94.89% in 30 and 229 seconds(s), respectively.
IoT RFID Lock Door Security System
Authors: Zabidi M S Z M , Yusof K H , Ahmad A S , Shahadan N H , Yusof K A , Yusof K Amri , Subari S N M
Published: August 2022

Wireless security system is widely used and favored by many industries, leading to mass growth of this technology. Prior to that, many advancement has been made throughout the decades. One of the popular wireless security systems is the Radio Frequency Identification System or RFID. RFID is favored over other systems due to myriads of its application in current systems like ATM cards, national ID card, toll system, parking lot system, and even mobile phones. This paper proposes an improved design of an RFID security system utilizing a Wi-Fi capable microcontroller (ESP-8266/ESP-12E). Combining the RFID system with an IoT system shall provide user with maximum control and monitor over the system. In this system, a RFID module (MCRF522) and an ESP-12E are used to identify a RFID card UID, in which a relay will turn on if the card is authorized, and the otherwise if not. The information will then be transmitted over the internet to a database, in which the information will be accessible via an app created specifically for the system for flexible configuration by the host user.
A visco-hyperelastic constitutive model of human periodontal ligament and the verification with finite element method
Authors: Liu Xin , Liu Mao , Tang Wencheng
Published: August 2022

The scientific basis of orthodontics is physics and Newtonian mechanics applied to the tooth-periodontal ligament-bone biologic system. The mechanical response of the periodontal ligament (PDL) to forces has a significant impact on bone remodelling and tooth movement. At the early stages, orthodontists mainly evaluated the PDL mechanical properties by in vitro experiments, which guided the use of forces in the orthodontic process. With the development of computers, finite element (FE) methods were increasingly used in the study of orthodontics. The phenomena and results of PDL mechanical tests are abstracted into constitutive equations. The identified constitutive equations are then implemented in finite element software. The finite element method could be used to simulate in vitro and in vivo experiments and predict the response of PDL under various complex working conditions. A visco-hyperelastic constitutive model is proposed and implemented in finite element technique based on prior static mechanical experiments of human PDL. Some complex experimental conditions are simulated to discuss the properties of the constitutive model.
Assessment of the Rheological properties of Aluminum dross in self-compacting concrete
Authors: Busari Ayobami , Loto Roland Tolulope , Eronmosele Esekhaigbe
Published: August 2022

This research assessed the rheological properties of aluminium dross in self-compacting concrete. Aluminium dross, solid waste from the aluminium processing industry, was used as a partial replacement for cement in the development of eco-friendly concrete. This was done in a bid to reduce the cost of management of this waste in track with the ‘waste to wealth’ initiative. In this article, aluminium dross was used as a partial replacement for cement at 0, 4, 8, 12, 16 and 20% content. The rheological test (workability) was carried out according to European Federation for Specialist Construction Chemicals and Concrete Systems (EFNARC) specifications. To this end the slump test, L-box, V-funnel and J-ring test was carried out at the replacement. The slump flow result indicated satisfactory result up to 20% addition, which indicates the good flowability characteristics of the concrete. The result of the research showed that aluminium dross, to a large extent, influenced the workability of the concrete produced. At 10% addition of this solid waste, the rheology was unsatisfactory from L-Box and V-funnel test result. The outcome of this research will guide researchers, engineers, and concrete users on the proper timing for mixing the special eco-friendly self-compacting concrete in the construction industry.
Influence of impurity boron on water resistance of basic magnesium sulfate cement
Authors: Zhang Xiaoyuan , Wu Chengyou
Published: August 2022

In this study, magnesium hydroxide was used as the precursor of magnesium oxide, mixed with different amounts of boric acid, and then calcined at 700°C and 1000°C to prepare different active magnesium oxide, and then BMSC specimens were obtained. By analyzing the effect of impurity boron on the compressive strength, microscopic morphology, hydration products, etc. of BMSC before and after soaking in water, the effect of impurity boron on the water resistance of BMSC was further explored. The results showed that the impurity boron had a great influence on the water resistance of BMSC. Th 1 e compressive strength of BMSC containing impurity boric acid decreased significantly after soaking in water, but its hydration product remained unchanged as 5·1·7 phase. Magnesium activity is low, crystallinity is low, and the dissolution rate of MgSO4 in the 5·1·7 phase is inversely proportional to the degree of crystallinity.
Research on preparation of 2D Cu nanomaterials
Authors: Xu Xiufeng , Dang Rui , Xie Mengmeng
Published: August 2022

Recently, metal nanosheets have been a promising material for application in nano-electrical devices. This study describes a chemical reduction preparation method of large-area Cu nanosheets in a facile condition using copper sulfate as source and glucose as reductant. The morphology and phase analysis of the synthesized copper nanosheets are measured by scanning electron microscope (SEM) and X-ray electron diffraction (XRD). The influences of several experimental parameters on the morphology of the products such as reducing agent and reaction temperature are investigated. It is found that by changing the molar ratio of copper ion to reductant, the thickness of copper nanosheets can be controlled. The obtained productions demonstrate excellent electrical conductivity.
Prediction of surface termination preference of out-of-plane ordered double-transition metal MXenes (o-MXenes) from first-principles calculations
Authors: Feng Xianghui , Bai Tianyu , Xiao Bing
Published: August 2022

Surface terminations greatly affect the MXene performance. On the basis of the first-principles thermodynamic calculations, the surface termination preference of 33 different out-of-plane ordered double-transition metal MXenes when prepared by etching the o-MAX phases with HF acid is revealed. By calculating the reaction enthalpy and reaction Gibbs free energy at finite temperature, it is concluded that when the outermost transition metal is a 3d-orbital transition metal, the surface termination is dominated by -F, and when the outermost transition metal belongs to 4d or 5d-orbital transition metal, the surface termination is mainly -O. And this preference law may be related to whether the outermost transition metal can donate enough electrons to surface groups.
Prediction of cutting force of particle-reinforced polymer matrix composites
Authors: Li Bo , Zhou Ping , Yan Ying , Sun Yujia
Published: August 2022

In this paper, the orthogonal cutting experiment and simulation analysis of Cu/PTFE composite materials are carried out with cemented carbide tools. The equivalent homogeneous model is adopted to realize the three-dimensional cutting simulation process. Compared with the experimental results, the predicted cutting force is in good agreement with that of the experimental results, and the deviation does not exceed 20%. The relationship between processing parameters and surface roughness under different cutting conditions is discussed in detail. The results show that the feed rate has a significant effect on the surface roughness, and the feed rate should be controlled during the machining process to obtain high surface quality. Through the observation of the turning surface, there are phenomena such as particle pulled off, cut off, and pressed in the processed surface morphology.
Phenolic acid extraction from orange peel with natural deep eutectic solvents
Authors: Lin Luoxuan
Published: August 2022

Orange peel were usually abandoned as waste. However, the valuable product in orange peel cannot be ignored. Essential oils, flavonoid and phenolic acid in orange peel are broadly exploited as important components in food, pharmaceutical and even cosmetic industries. Compared to conventional organic solvents, Natural Deep Eutectic Solvents (NADESs) is a category of environmental-friendly green solvents, providing a solution for toxic residues. Meanwhile, with the properties of non-flammability, low toxicity, non-volatility, high stability and low melting points, NADESs are promising in the application of plant extraction, such as oil and phenolic acid extraction. In recent researches, choline chloride based NADESs display excellent extraction properties from natural sources. Choline chloride as hydrogen bond acceptor and glucose as hydrogen bond donor, with ultrasonic-assisted extraction method, phenolic acid were extracted from orange peel. Different ratio of choline chloride and glucose were conducted in the experiment. In the result, when choline chloride/glucose/water (reaction medium) ratio is 5:2:5, the DPPH free radical scavenging activity reaches optimum; while when the ratio is 1:1:1, the tested tyrosinase inhibition rate reaches the largest, which means the extracted phenolic acid with NADESs is promising to be applied into pharmaceutical and cosmetic industries.
N-butyl oleate catalyzed- synthesized by triethylamine citrate lonic liquid
Authors: Zhou Ningning , Yang Liancheng , Wang Yuehan , Ding Yunlong
Published: August 2022

Ionic liquids have many unique physical and chemical properties and are attracting more and more attention. They are considered to be a new type of green solvent that can replace traditional organic solvents and are environmentally friendly. They have attractive application prospects in many fields. The triethylamine citrate ionic liquid was used as a catalyst to catalyze-esterificate-synthesis n-butyl oleate with oleic acid and n-butanol. Research on the preparation, optimization and the reacted process of n-butyl oleate of the new catalyst were conducted. Experimental analysis shows triethylamine and citric acid reacted under certain conditions achieved the preparations of the catalyst(triethylamine citrate: citric acid=3.5:1, 1h, 40 °C), and then n-butanol oleate was synthesized according with follows conditions(oleic acid: n-butanol=1:1, 3h, 140°C, catalyst dosage:10%), the esterified rate was reached about 60%. In contrast, the reacted conditions of preparing catalyst followed that (triethylamine citrate: citric acid=3:1, 1h, 8°C), and then n-butanol oleate was synthesized according with follows conditions(oleic acid : n-butanol=1:1, 3h, 140°C, catalyst dosage:10%), the esterified rate was reached above 92%. Meanwhile, the new catalyst of triethylamine citrate ionic liquid can be recycled, zero pollution, simple production process, high catalytic yield, can avoid effectively strong corrosion from catalyst to devices, not easy to save and high volatility etc. unfavorable factors and based on above esterification rate of n-butyl oleate was improved effectively. Due to the unique properties of ionic liquids, it is widely used in various fields of chemical research. Ionic liquids have been used as reaction solvents in many types of reactions.
Research on triazine reaction, heat resistant and dielectric properties of cyanate ester resin catalyzed by bisphenol AF
Authors: Zhou Kaiyun , Sun Xiaopeng , Wang Yanan , Zhao Weiwei , Su Tao
Published: August 2022

Cyanate ester (CE) resins possess a wide variety of attractive features that make them suitable for both electronic and aerospace composite applications. However, high curing temperature and long curing time limit the application range of CE resins. In this study, curing reaction, heat resistant and dielectric properties of bisphenol A-based cyanate ester (BACY) resin catalyzed by bisphenol AF (BPAF) were investigated by means of differential scanning calorimetry, Fourier transform infrared, dynamic mechanical analyser and dielectric properties analyser. The incorporation of the BPAF decreased the curing temperature and showed a strong catalytic effect in cyclotrimerization reaction of BACY. BACY resin catalyzed by 4 phr BPAF at 180 °C post-cured for 5 h presented high curing degree of 92.8% and glass transition temperature of 247.4 °C. Moreover, BACY resin catalyzed by 4 phr BPAF at 180 °C post-cured for 5 h exhibited excellent dielectric properties (ε and tan δ equal to 2.87 and 0.0084) comparable to commercial modified cyanate ester resin post-cured at 200 °C for 10 h. These results suggest that catalyst BPAF possesses promising potential application in meeting low-temperature short-term curing of high-performance cyanate ester resin based wave-transparent composites.
Research on Thermal Property of the Shell Powder-Filled Polybenzoxazine Composites
Authors: Feng Tiantian , Zhang Xiumei , Lv Chang , Zhong Xiaohuang
Published: August 2022

In recent years, the study of benzoxazine based composites has become a research hotspot. In this paper, a set of the shell powder-filled polybenzoxazine composites were prepared. The curing behavior and thermal properties of the corresponding composites were studied by differential scanning calorimeter, dynamic mechanical analyzer and thermogravimetric analysis. The results revealed that the glass transition temperature of the composite improved 22 °C with the shell powder content added to 30%. Besides, the 5% decomposition temperatures of all the resulted composites were higher than 390 °C, which indicated that the addition of shell powder improved the thermal stability of benzoxazine resin.
Preparation of Nano-SiO2 Modified PA66 Microfiltration Membrane and Treatment of Oily Wastewater
Authors: Wang Jiafan , Wang Beifu , Zhang Chenxiao , Nie Lihong
Published: August 2022

With the development of industry, more and more oily wastewater is discharged into the water, which brings great harm to the ecological environment and human health. Membrane separation technology is a very promising technology for oily wastewater treatment. In this experiment, a 1:1 mixed solution of formic acid and dichloromethane (FA/DCM) was used as a solvent to prepare a PA66 microfiltration membrane by evaporation method, and nano-SiO2 was used to modify the PA66 with the determined formula. The apparent morphology, hydrophilicity and mechanical properties of the membrane were characterized by scanning electron microscopy, contact angle test and tensile test, and the effect of treating oily wastewater by microfiltration membrane before and after modification was analyzed. The results show that the mechanical strength and hydrophilicity of the microfiltration membrane are improved after modification by SiO2, and the sewage treatment effect is better. The removal rates of unmodified microfiltration membrane to total suspended solids, chemical oxygen demand and oil concentration are 55%~96%, 50%~85% and 55%~92%; the removal rates of modified microfiltration membrane to total suspended solids, chemical oxygen demand and oil concentration are 98%~99%, 91%~95% and 95%~99%.
Graphene paper based liquid sensor for micro volume acetone detecting
Authors: Wang Yanan , Sun Xiaopeng , Zhou Kaiyun , Wu Xiao , Huang Xinzuo , Yang Maowei
Published: August 2022

Sensors with accurate detection of various liquids have attracted increasing research interests in environmental protection and organic solvents transporation. In this paper, liquid sensor based on laser induced graphene paper (LIGP) was proposed, and successfully used for the rapid detection of micro volume liquid. The processing-structure-property relationship was systemically studied. LIGPs with different morphologies exhibited various sensitivities and showed good reproducibility and fast response. The response mechanism related to contact resistance between some adjacent graphene flakes/fibers was proposed. With the key findings, LIGP liquid sensors can be used as the detector for accurate identification of different solvents and have great potential in monitoring organic solvent leakages of pipelines and fabrication of smart anti-corrosion composite structures.
Microstructural Black Swans
Authors: Boyce B L
Published: August 2022

Black swans are a metaphor for rare events with extreme consequences. In the domain of structural materials, black swans represent features in the microstructure that lead to catastrophic failure; as a result of their rarity, they are difficult to observe and often overlooked. These unusual weakest-link features are described variously as incipient, emergent, or anomalous. They give rise to localization, percolation, or avalanche events such as fracture, ductile rupture, dielectric breakdown, corrosion pit nucleation, and fatigue-crack initiation; as such, they are limiting cases in the concept of a representative volume. In this perspective, three examples are given of rare microstructural features and how they limit the mechanical reliability of structural metals. After taking stock of these examples, a future outlook considers the need for high-throughput testing and non-destructive characterization as well as detection algorithms and materials modelling strategies, including accelerated machine learning methods, that can capture anomalous events.
Topological aspects of mean-field crystallographically resolved models
Authors: Kestens L.A.I. , Nguyen-Minh T. , Ochoa Avendaño J. , Ghiabakloo H. , Van Bael A.
Published: August 2022

It is well-known that the crystallographic texture of a polycrystalline aggregate can be represented by the Orientation Distribution Function (ODF). A similar statistical approach can be extended to other microstructural state variables that are of relevance in the context of obtaining microstructurally based and quantitatively accurate structure-properties relations. In principle such statistical representations are of a non-topological nature, in contrast to an RVE (Representative Volume Element) description of the microstructure. However, by including additional variables to the statistical descriptor specific features of the topology may be taken into account. In this paper the example will be shown on how the plastic anisotropy simulation of a conventional deep drawing grade of Interstitial Free (IF) steel can be improved by considering the crystallographic misorientation of pairs of neighboring crystals, which represent the basic structural units of the 2-point mean field ALAMEL crystal plasticity model. In another example it will be shown how the recrystallization texture of the same deep drawing IF steel can be modelled with improved accuracy if the Strain Induced Boundary Mechanism (SIBM) is taken into account whereby a crystal orientation of low stored energy grows into a neighboring orientation of high stored energy.
Tensile deformation-induced twinning in an austenitic low density steel over a wide range of temperature
Authors: Wang Hui , Liang Jiangxiong , Shi Zhiyue , Wang Cunyu , Zhang Xiaodan , Cao Wenquan
Published: August 2022

A Fe30Mn11Al1CNbV low-density steel was processed by solid solution treatment and deformed at different temperatures from -196°C to +200°C by tensile testing. It was found that the deformation microstructure is mainly dominated by thin dislocation slip bands during tensile deformation, and deformation twinning was found near grain boundaries at a strain of 0.5, regardless of deformation temperature. The stacking fault energy is calculated by consideration of both chemical composition and the deformation temperature, which is high and normally should not initiate deformation twinning. However, deformation twinning is occasionally observed in the deformation microstructure at room temperature, and becomes to be one of the dominating features at liquid nitrogen temperature. Based on the analysis of work hardening and microstructure evolution, it is proposed that the deformation behaviour of the austenitic low density steel is controlled by the continuous thinning of dislocation slip bands at temperatures of 25°C and 200°C, but by a synergistic behaviour of slip bands and deformation twinning at -196°C.
Mechanics of accelerated strain hardening in harmonic-structure materials
Authors: Chatellier Joséphine , Sjögren-Levin Elis , Ameyama Kei , Orlov Dmytro
Published: August 2022

Harmonic-structure (HS) design is one of the most efficient in the family of architected gradient-structure materials recently attracting increasing attention in global material science community due to leading structural performance characteristics. This work studiesin situthe mechanics of plastic deformation in HS materials on the example of commercially pure nickel (Ni) during uniaxial tensile loading. It reveals that strain partitioning between ultrafine and coarse grain fractions in HS Ni commences already at early stages of plastic deformation. Slow accumulation of strain in the ultrafine-grain regions leads to the slow consumption of ductility resource, while accelerated accumulation of strain in the coarse-grain regions leads to an accelerated strain hardening. These effects combined with evolving variations of strain tensor components have synergetic effect leading to the unique plastic behaviour and excellent structural performance of HS materials.
A phase-field approach to study BCC precipitate evolution in FCC AlxCrFeNi medium entropy alloy including elastic effects
Authors: Zuo X , Moelans N
Published: August 2022

A phase-field approach is presented to simulate the evolution of a BCC precipitate in an FCC matrix for AlxCrFeNi based medium entropy systems. The CALPHAD composition dependence of the Gibbs energies and diffusion mobilities for this quaternary alloy are introduced in the model using ThermoCalc with TCHEA2 and MOBNI4 databases. Heterogeneous elastic properties are assumed for the FCC and BCC phase computed for the quaternary system. The effect of the elastic stresses due to lattice mismatch on precipitate shape, evolution and matrix composition is presented for a single BCC precipitate in and FCC matrix. We find that the elastic effects are considerable.
Origin of strain localization at twin boundary in Inconel 718 superalloy fabricated by laser powder bed fusion
Authors: Li X C , Wu Y N , Yang R , Zhang Z B
Published: August 2022

Microscale strain evolution and mechanistic origin of strain localization of Inconel 718 superalloy fabricated by laser powder bed fusion was investigated. Strain maps obtained by in-situ high resolution digital image correlation (HRDIC) demonstrate that localized dislocation activities and severe strain localization occur along the coherent twin boundaries (TBs). Such localized dislocation plasticity along TBs exhibits no dependency on the elastic anisotropy and the length of TBs, and the determining factor of the occurrence of localization is the maximum Schmid factor of the TBs. By employing correlative characterizations of TBs, γ″ precipitate and dislocation slip bands, it is found out that the precipitation of V-shaped γ″ along TBs incurs the formation of precipitates denuded zones, which takes the responsibility for localized plasticity and severe strain localization at TBs.
Lattice rotations during channel-die compression at high strain rates in copper single crystals of {110}<112>, {112}<111> and {123}<634> orientations
Authors: Mania I , Paul H , Chulist R
Published: August 2022

The microstructure and texture evolutions of high purity copper single crystals of Br(1-10)[112], C(112)[11-1] and S(346)[63-5] initial orientations were investigated to evaluate the influence of high strain rate on the intensity of twinning and shear banding. The samples were deformed up to 60% in a channel-die at a strain rate of 7 × 105 s-1 using explosive energy to propel the punch. The microstructure was characterized by optical microscopy as well as scanning and transmission electron microscopy. High strain rates of deformation of C and S-oriented single crystals lead to massive deformation twinning. Despite the identification of three families of compact clusters of twins of two generations, the microstructure and texture of both single crystals are practically dominated by the twinning on only one co-planar slip plane. The common rotation of twin-matrix layers, within the narrow area, combined with deformation twinning in the re-oriented matrix are responsible for final SB texture formation. This mechanism contributes to the formation of orientations from the neighborhood of the {110}<100> orientation. The {110}<112> orientation, stable during deformation in channel-die in the range of ‘conventional’ strain rates, lost its stability giving rise to intense twinning and deformation bands across the deformed specimen.
Challenges related to tomographic reconstruction of 3D intragranular orientation fields in the presence of orientation relationships
Authors: Liu Z , Viganò N , Ludwig W
Published: August 2022

X-ray diffraction contrast tomography (DCT) is a near-field diffraction imaging technique to characterize the 3D shape and crystallographic orientation of grains within polycrystalline samples. The presence of orientation relationships as such encountered between Σ3n annealing twins found in Cu and Ni lead to systematic diffraction spot overlap, since a significant fraction of the lattice planes is shared between the parent and twin crystal lattices. If not correctly addressed, these overlaps will lead to artifacts in the individual grain reconstruction. In this paper we introduce a strategy for joint, tomographic reconstruction of Twin Related Domains (TRD) and cost function weights into DCT to improve the grain reconstruction quality. A large-grained polycrystalline sample made from pure Ni is used for testing this approach and its ability to reveal intragranular orientation gradients related to plastic strain localization at the onset of plastic deformation in this type of materials.
Effects of alloying, microstructure and texture on the strength–ductility trade-off in layered aluminum
Authors: Xia Y P , Wu H , Miao K S , Geng L , Fan G H , Yu T , Juul Jensen D
Published: August 2022

Tailoring constituent layers can lead to improved mechanical properties of layered metals. In this work, we designed and fabricated two samples of layered Al. One sample with AA3003 and AA1060 layers and the other with only AA1060 layers. The effects of these designs on the deformation behaviors are revealed by in-situ monitoring of the local strain evolution. It was found that larger microstructural and textural variations can lead to a larger difference in transverse compressive strain between constituent layers under uniaxial tension, which indicates more significant defomation incompatibility and thus a larger strain gradient caused by the constraint effect. The effects of the texture on the transverse compressive strain levels was analysed by the Lankford values calculated by the visco-plastic self-consistent method. Furthermore, the fracture behaviors of the two samples are compared and discussed based on the cross-sectional fracture morphologies. This work illustrates the potential of tailoring layered metals for a superior strength–ductility combination.
Advanced time-resolved characterization of Stress Assisted Grain Boundary Oxidation of 718 Ni superalloy
Authors: Resende P D , Viganò N , Bardel D , Réthoré J , Ludwig W
Published: August 2022

Nickel superalloys are used for harsh condition application cases as they have high chemo-thermomechanical stability. However, they can suffer from embrittlement due to stress corrosion cracking. This effect is difficult to observe as it can take place at long time scales. Here we propose a feasible experiment to study stress assisted grain boundary oxidation, a phenomenon that has similar mechanisms involved that can take place in laboratory compatible time scales. We observed the event using phase and diffraction contrast tomography while applying monotonic loading of the sample at 650 °C. This initial analysis shows that the experimental setup is a good candidate for the study of such degradation mechanism.
Magnetoresistive behaviour of ternary Cu-based materials processed by high-pressure torsion
Authors: Kasalo M , Wurster S , Stückler M , Zawodzki M , Weissitsch L , Pippan R , Bachmaier A
Published: August 2022

Severe plastic deformation using high-pressure torsion of ternary Cu-based materials (CuFeCo and CuFeNi) was used to fabricate bulk samples with a nanocrystalline microstructure. The goal was to produce materials featuring the granular giant magnetoresistance effect, requiring interfaces between ferro- and nonmagnetic materials. This magnetic effect was found for both ternary systems; adequate subsequent annealing had a positive influence. The as-deformed states, as well as microstructural changes upon thermal treatments, were studied using scanning electron microscopy and X-ray diffraction measurements. Deducing from electron microscopy, a single-phase structure was observed for all as-deformed samples, indicating the formation of a supersaturated solid solution. However, judging from the presence of the granular giant-magnetoresistive effect, small ferromagnetic particles have to be present. The highest drop in room temperature resistivity (2.45% at 1790 kA/m) was found in Cu62Fe19Ni19 after annealing for 1 h at 400 °C. Combining the results of classical microstructural studies and magnetic measurements, insights into the evolution of ferromagnetic particles are accessible.
Heterogeneous microstructure and failure analysis of yaw gear rings
Authors: Zhang Xiaodan , Pedersen Niels Leergaard , Klit Peder , Jensen Dorte Juul
Published: August 2022

The microstructure and hardness of two cracked and failed steel (42CrMo4) teeth from two different yaw rings have been investigated. It is shown that the surface quenching and tempering treatments introduce heterogeneous microstructures with a low-temperature tempered hard martensite surface layer and a high-temperature tempered matrix. This is common to both teeth, however, the gradient microstructure and hardness are different for these two yaw rings. It is suggested that this difference in gradient strongly affects cracking and failure. The failure mechanisms for the two teeth are discussed based on the microstructure and hardness analysis.
A CPFEM based theoretical analysis of strains resolved by the microstructural feature tracking method
Authors: Li R , Quey R , Zhang Y , Kobayashi M , Oddershede J , Juul Jensen D
Published: August 2022

In this work, it is investigated how grain boundaries influence the local strain determination by the microstructural feature tracking (MFT) algorithm. In this method, tetrahedra are used as the strain calculation unit. We apply the MFT processing procedure on data obtained by a crystal plasticity finite element modeling (CPFEM) simulation to explore the uncertainties in the calculated strains caused by grain boundaries. Effects of tetrahedron types and radius ratios are discussed.
Microstructure and properties of cold-drawn Cu and Cu-Fe alloy wires
Authors: Yang Fei , Zhang Xiaodan , Fang Feng
Published: August 2022

Copper and Cu-Fe alloy wires were cold drawn at room temperature, and the microstructure and properties were characterized and analyzed. The results show that, at the same drawing strain, the strength and ductility of Cu-Fe wires are higher than those of copper wires. At a drawing strain of 4, the tensile elongation of Cu-Fe alloy wires is about 5%, much higher than 2% for pure copper wires. For Cu-Fe wires, with increasing drawing strain, the Fe phase is elongated along the drawing direction and forms a fiber structure with a <110> texture. In addition to the <111> and <100> fiber textures in the copper wire, a high-intensity of texture with a <112> orientation forms in Cu-Fe alloy wires. The ductility of the Cu-Fe alloy wires is greatly preserved due to dynamic recrystallization. Moreover, with the additional refining effect of nano-copper fibers in the Fe phase, the strength of the material is greatly improved.
Effect of annealing on microstructure in railway wheel steel
Authors: Nikas Dimitrios , Zhang Yubin , Ahlström Johan
Published: August 2022

Railway wheels are commonly made from medium carbon steels (~0.55 wt.% C), heat treated to a near pearlitic microstructure with 5–10% pro-eutectoid ferrite. During the operation of freight trains, where block brakes are used, high thermal loads occur together with the high contact stresses, which combined can affect the mechanical properties of the material. In this study, the effects of annealing on local microstructure and mechanical properties in pearlitic railway wheel steel were investigated using electron microscopy and micro-hardness. It is found that after annealing at 650 °C, the room temperature hardness reduces about 25%, accompanied by significant spheroidization of cementite in the pearlitic colonies, though the size and the orientation gradients of the pearlitic colonies have not changed much. The relationship between the microstructural changes and the mechanical properties are discussed.
Importance of Microstructure on Precipitation in Tempering of Martensitic Steels
Authors: Hou Z , Babu R P , Zhang L
Published: August 2022

Precipitation hardening is one of most effective strengthening mechanisms in steels, and much research has been performed in the past. To evaluate the contribution of precipitates, the quantitative features of precipitates including mean size and particle size distribution etc., are vital and needed. However, the predictive modeling of precipitation is still a challenge so far, especially on a quantitative level. Thus, in the present work, precipitation of carbides after tempering of martensitic Fe-Cr-C alloys, consisting of hierarchically arranged substructures within the prior-austenite grains, namely packets and blocks of individual laths, up to 1000h has been investigated. Experimental measurements using electron microscopy and modeling using a Langer-Schwartz theory with the Kampmann-Wagner -Numerical (KWN) method have been conducted. The importance of a proper definition of the initial microstructure for predictive modeling is discussed, in terms of the comparison of calculated and experimental results.
Characterization of zinc uptake and translocation visualized with positron-emitting 65Zn tracer and analysis of transport-related gene expression in two Lotus japonicus accessions
Authors: Noda Yusaku , Furukawa Jun , Suzui Nobuo , Yin Yong-Gen , Matsuoka Keita , Kawachi Naoki , Satoh Shinobu
Published: August 2022

Background and Aims

Zinc (Zn) is an essential element for humans and plants. However, Zn deficiency is widespread and 25 % of the world’s population is at risk of Zn deficiency. To overcome the deficiency of Zn intake, crops with high Zn content are required. However, most crop-producing areas have Zn-deficient soils, therefore crops with excellent Zn uptake/transport characteristics (i.e. high Zn efficiency) are needed. Our objective was to identify the crucial factors responsible for high Zn efficiency in the legume Lotus japonicus.

Methods

We evaluated Zn efficiency by static and real-time visualization of radioactive Zn (65Zn) uptake/transport in two L. japonicus accessions, MG-20 and B-129, that differ in Zn efficiency. The combination of visualization methods verified the dynamics of Zn accumulation and transport within the plant. We compared gene expression under a normal Zn concentration (control) and Zn deficiency to evaluate genetic factors that may determine the differential Zn efficiency of the accessions.

Key Results

The accession B-129 accumulated almost twice the amount of Zn as MG-20. In the static 65Zn images, 65Zn accumulated in meristematic tissues, such as root tips and the shoot apex, in both accessions. The positron-emitting tracer imaging system (PETIS), which follows the transport process in real time, revealed that 65Zn transport to the shoot was more rapid in B-129 than in MG-20. Many genes associated with Zn uptake and transport were more highly expressed in B-129 than in MG-20 under the control condition. These gene expression patterns under Zn deficiency differed from those under the control Zn condition.

Conclusions

PETIS confirmed that the real-time transport of 65Zn to the shoot was faster in B-129 than in MG-20. The high Zn efficiency of B-129 may be due to the elevated expression of a suite of Zn uptake- and transport-related genes.
Detection of orthologous exons and isoforms using EGIO
Authors: Ma Jinfa , Wu Jane Y , Zhu Li
Published: August 2022

Motivation

Alternative splicing is an important mechanism to generate transcriptomic and phenotypic diversity. Existing methods have limited power to detect orthologous isoforms.

Results

We develop a new method, EGIO, to detect orthologous exons and orthologous isoforms from two species. EGIO uses unique exonic regions to construct exon groups, in which process dynamic programming strategy is used to do exon alignment. EGIO could cover all the coding exons within orthologous genes. A comparison between EGIO and ExTraMapper shows that EGIO could detect more orthologous isoforms with conserved sequence and exon structures. We apply EGIO to compare human and chimpanzee protein-coding isoforms expressed in the frontal cortex and identify 6912 genes that express human unique isoforms. Unexpectedly, more human unique isoforms are detected than those conserved between humans and chimpanzees.

Availability and implementation

Source code and test data of EGIO are available at https://github.com/wu-lab-egio/EGIO.

Supplementary information

Supplementary data are available at Bioinformatics online.
Associations between isoflavone exposure and reproductive damage in adult males: evidence from human and model system studies
Authors: Yang Wang , Deng Jiuyang , Gao Jianfang , Yang Huan , Chen Qing , Niya Zhou , Ling Xi , Zhang Guowei , Zou Peng , Sun Lei , Huang Linping , Liu Jinyi , Cao Jia , Ao Lin
Published: August 2022

It is controversial whether exposure to isoflavones exerts male reproductive toxicity. The aim of this study was to investigate whether isoflavone exposure during adulthood could have deleterious impacts on male reproductive health by the cross-sectional study, animal experiments, and in vitro tests. In the cross-sectional study, we observed that urinary isoflavones were not significantly associated with semen quality including sperm concentrations, sperm count, progressive motility, and total motility, respectively. However, negative associations were found between plasma testosterone and urinary Σisoflavones, genistein, glycitein, and dihydrodaidzein. In the animal experiments, serum and intratesticular testosterone levels were decreased in mice exposed to several dosages of genistein. Genistein administration caused upregulation of estrogen receptor alpha and downregulation of cytochrome P45017A1 protein levels in testes of mice. In vitro tests showed that genistein caused a concentration-dependent inhibition of testosterone production by TM3 Leydig cells. Elevated protein expression of estrogen receptor alpha and decreased messenger RNA/protein level of cytochrome P45017A1 were also observed in genistein-treated cells. Protein level of cytochrome P45017A1 and testosterone concentration were significantly restored in the estrogen receptor alpha small interferring RNA-transfected cells, compared to cells that treated with genistein alone. The results demonstrate that exposure to isoflavones during adulthood may be associated with alterations of reproductive hormones. Particularly, genistein, which inhibits testosterone biosynthesis through upregulation of estrogen receptor alpha in Leydig cells of mice, might induce the disruption of testosterone production in human. The present study provides novel perspective into potential targets for male reproductive compromise induced by isoflavone exposure.