bluuebunny/crossref_metadata_2025 huggingface dataset:
The diversified teaching reform of The mixed flipped classroom Python Foundation course is aimed at deep learning
Authors: Xiao Xiaoxu
Published: December 2020

Under the background of deep learning, the reform of diversified teaching mode is related to the community of teachers and students, and the traditional one-way independent learning of students is transformed into interactive independent learning of teachers and students. Through the MOOC, SPOC, such as teaching case analysis, to explore how to build a hybrid flip classroom teaching mode, use of the advantages of various platforms together, fully applied to the classroom teaching, the reasonable using and sharing high quality teaching resources, to ensure the ability of the students’ learning and literacy, conducive to the students’ active learning and teacher’s guidance and the guidance of thinking, to increase the interaction between students and teachers, the construction of teachers and students “learning community” hybrid flip diversified teaching mode. This mode is applied in the teaching of Python Foundation course to promote the teaching reform of the course, help teachers improve the teaching quality, and provide reference for solving the problems faced by classroom teaching in colleges and universities as well as the teaching research of “MOOC+SPOC+ Flipped classroom” teaching mode.
Analysis of Blocking Middle Seat Policy of Delta Airline
Authors: Li Xiaoyu
Published: December 2020

The main content of the research is about the seat blocking policy of Delta airline and its influences. The idea of the research comes up as airline industry is one of the most influenced industry by covid-19 pandemic and Delta’s action in this severe situation is worth to analyze. SWOT analysis will be conducted in this research, force field analysis, final account analysis and ratio analysis to study the decision of empty the middle seat. From the research, the author wants to have the conclusion about how the policy is going to affect the delta airline, and whether the policy should be kept or not. The conclusion is that Delta airline should keep on the blocking seat policy because almost the passengers has good impressions on the company.
Study and Shutoff Experiment on Mechanical Properties of Multistage Resin Composite Ductile Cement
Authors: Liu Shasha , Zhang Yanru , Yan Haijun , Liu Yun , Xie Gang , Lu Cheng , Jing Jizhe , Wei Aijun , Qin Zhonghai , Shi Lei
Published: December 2020

In view of the traditional inorganic cement-based material hydration shrinkage caused by the impact of performance defects range of application, applying the principle of doping dispersion and compact packing, a multistage resin composite ductile cement slurry system with different temperatures was constructed. The compatibility, thickening and mechanical evaluation tests were carried out to optimize the resin type, doping amount and method. The results show that the thickening of the composite system is controllable, and the addition of resin is beneficial to improve the elastic deformation, whereas easy to pile up if adding extra amounts, and the compressive strength reduced. At the same time, adding resin first is beneficial to disperse in the cement gap. Compared with cement-based materials, the compressive strength increased 7% to 13%, the elastic modulus decreased 10% to 15%, and the deformation capacity increased 14% to 22%. Field test shows that it has good sealing performance and remarkable effect of oil increasing and dewatering, which provides a new technical means for controlling casing leakage and ensuring its normal production.
The Role of Aβ in the Development of Alzheimer’s Disease and its Mechanisms
Authors: Jin Yifei
Published: December 2020

Alzheimer’s disease (AD) is chronic neurodegenerative dementia representing the most common cause of dementia in the elderly population. It is a major source of morbidity, mortality, and healthcare expenditure worldwide. Although the molecular and cellular properties related to AD have been demonstrated decades before the onset of clinical symptoms, AD’s pathogenesis is still unknown as a combination of risk factors causes it. Today, pathogenesis theories focused on senile plaques (SP) formed by the extracellular accumulation and deposition of Aβ peptides and neurofibrillary tangles (NFTs), which are composed of the hyperphosphorylated tau protein. Furthermore, growing evidence points out that toxic Aβ plays a primary causal role in the induction and transmission of pathology and neuronal dysfunction and loss. Therefore, Aβ is crucial to the development of AD and is a noteworthy issue in AD research. This review shows the formation of Aβ and the differences of cytotoxicity of its various isoforms and aggregation states. It also summarizes the mechanisms by which Aβ induce AD through its neurotoxicity and state how these mechanisms interact and reinforce each other.
Research on the Problems and Development of Small and Medium Enterprises in the Pearl River Delta
Authors: Huang Liang , Ti Haowei , Pei Leigang , Ma Ding
Published: December 2020

Since the reform and opening up, the economy of the Pearl River Delta has achieved rapid development and remarkable results. Small and medium-sized enterprises in the region have also achieved rapid development in terms of quantity and quality, and have become an important part of the region. However, with economic globalization, because of continuous changes in the external environment, and its own industrial upgrading and structural adjustment, even if small and medium-sized enterprises in the Pearl River Delta region have advantages compared with other regions in China. However, there are still problems in the development process. The article mainly analyzes the financing difficulties of SMEs in the Pearl River Delta region and the brain drain in recent years, and gives corresponding countermeasures. Since small and medium-sized enterprises occupy an important position in the economy of the Pearl River Delta region, they can not only promote technological innovation and boost domestic demand for production, but also drive the employment rate to rise. Therefore, the development of small and medium-sized enterprises in the region has played a positive role in the economic progress of the Pearl River Delta region, and the place has also promoted economic development.
Risk estimation of large complex bridge construction based on factor analysis
Authors: Li Qingfu , Lei Jia , Zhang Hua
Published: December 2020

Based on the basic theory of factor analysis, this paper analyzes the risk factors of large-scale bridge construction through questionnaire surveys and expert scoring methods, summarizes the basic data of factors affecting bridge construction, and then analyzes the possible application of factor analysis in bridge construction risk analysis Sex. Based on the statistical processing of the data by the IBM SPSS Statistics V21.0 software, the applicability of the method was verified through factor extraction, factor rotation, consistency analysis and construction validity, and pointed out that six types of main factors affecting the safety of bridge construction Factors, calculate the importance index and correlation of each risk factor, and sort them by size, so as to estimate the risk consequences of bridge construction in a targeted manner, and invest reasonable efforts to control according to the size and importance of the risk, so that the risk control process is more Reasonable and targeted.
Research on Application of Digital Technology in Anhui Intangible Cultural Heritage Popularization Design-Take the manufacture technology of Huangshan Maofeng tea as an example
Authors: Li Linsen , Li Muyu , Deng Ting
Published: December 2020

Taking the manufacture technology of Huangshan Maofeng intangible cultural heritage in Anhui as a study case, this paper discussed the application of digital technology in expressing intangible cultural heritage science popularization, and proposed protection and inheritance strategies of intangible cultural heritage in Anhui based on information visualization and science popularization. By constructing digital communication model of intangible cultural heritage, it popularized knowledge of intangible cultural and the production process, making the intangible cultural heritage closer to ordinary people’s life, and offering a new protection and communication approach for intangible culture heritage, which applies to the development in this time.
Evaluation of Heavy Metal Level in Soil of Typical Alpine Grassland Communities
Authors: Shi Huilan , Liu Zhiyong , Duan Zhonghua , Sun Jiancai , Yang Sha , Zhang Jiexue , Wu Yukun , Deng Deting , Shi Jianjun
Published: December 2020

Objective: Through the investigation, determination and analysis of heavy metals in the soil of typical alpine grassland community, five kinds of alpine grasslands with different degeneration degree of Maduo County in Alpine area, two kinds of alpine grassland with high Maqu County, high Alpine desert along the coast of Qinghai Lake, alpine thickets in the yellow South region, Alpine wetlands, The condition of soil heavy metals in alpine meadow and other communities is analyzed, which provides scientific guidance for the ecological protection measures of typical alpine grassland communities, and provides a basis for the sustainable utilization of Alpine grassland. Methods: The content of various kinds of heavy metals in soil samples was determined by ICP-MS, and the pollution status of heavy metals was analyzed by means of single factor pollution index method, Nemero comprehensive pollution index method and potential ecological risk index method by using Excel. Results: (1) The content of Cd in Maduo, Maqu, Qinghai Lake and Huangnan was 1.74, 0.97, 1.84 and 1.06 times times the soil environment background respectively, and the content of Hg in Maqu was 1.36 times times that of soil environmental background value. The variation coefficient of Hg and Pb in Maqu and the coefficient of variation of Cd in Qinghai Lake are more than 100%, which is in the degree of high variation, which is greatly influenced by man. (2) The highest total pollution index in the 4 sample places was in the area of MA diversity, at 1.33. The second is the Huangnan sample, with an exponential value of 0.86. The Nemero comprehensive pollution Index of the Maqu sample is 0.77. The index value of Qinghai Lake sample is the lowest, at 0.61. (3) The highest potential ecological hazard index is the most diverse, in 0-10, 10-20, 20-30cm three soil layers are 96.96, 103.58, 102.46, Maqu in 0-10, 10-20cm soil, the potential ecological hazard index is 65.70, 71.01, the potential ecological hazard index of Huangnan in three soil layer is 78.23, 73.42 and 72.84 respectively, which refers to the smallest value of Qinghai Lake sample, three, 51.07 and 51.72 in 51.48 soil layer respectively. Conclusion: The Nemero comprehensive pollution Index of Qinghai Lake sample is less than 0.7, at the level of cleanliness, the exponential value of Huangnan and Maqu two samples is between 0.7~1, at the level of cordon, and the exponential value of ma variety is between 1~2, at the level of mild pollution. The comprehensive potential ecological hazard index of 80~160 has the potential ecological risk of strength, and the exponential value of the other three samples is between 40~80, which has medium potential ecological risk. Generally, the pollution degree of heavy metals is small in the whole alpine grassland area.
Conservation paradox of giant arapaimaArapaima gigas(Schinz, 1822) (Pisces: Arapaimidae): endangered in its native range in Brazil and invasive in Indonesia
Authors: Marková Jana , Jerikho Rikho , Wardiatno Yusli , Kamal Mohammad Mukhlis , Magalhães André Lincoln Barosso , Bohatá Lucie , Kalous Lukáš , Patoka Jiří
Published: December 2020

Ornamental aquaculture is known to be one of the main sources of non-native species and Indonesia has been identified as one of the leading suppliers of these organisms worldwide. Released or escaped ornamental aquatic animals can establish new populations and become invasive. On the other hand, some invasive species can be also endangered in their native range, which is called the “Biodiversity Conservation Paradox”. This is true forArapaima gigas, one of the popular ornamental creatures and the largest bony fish of all, which is threatened in its native range in parts of Amazonia and which has been found to occur in various localities in Java and Sumatra in Indonesia. Based on climate matching we found the vast majority of Indonesian territory to be suitable for this species establishment. Keeping in mind the size and predatory behaviour ofA.gigas, we discussed possible consequences of its spread and impacts on native biota in Indonesia.
Further investigation of the characteristics and biological function ofEimeria tenellaapical membrane antigen 1
Authors: Wang Qingjie , Zhao Qiping , Zhu Shunhai , Huang Bing , Yu Shuilan , Liang Shanshan , Wang Haixia , Zhao Huanzhi , Han Hongyu , Dong Hui
Published: December 2020

Apical membrane antigen 1 (AMA1) is a type I integral membrane protein that is highly conserved in apicomplexan parasites. Previous studies have shown thatEimeria tenellaAMA1 (EtAMA1) is critical for sporozoite invasion of host cells. Here, we show that EtAMA1 is a microneme protein secreted by sporozoites, confirming previous results. Individual and combined treatment with antibodies of EtAMA1 and its interacting proteins,E. tenellarhoptry neck protein 2 (EtRON2) andEimeria-specific protein (EtESP), elicited significant anti-invasion effects on the parasite in a concentration-dependent manner. The overexpression of EtAMA1 in DF-1 cells showed a significant increase of sporozoite invasion. Isobaric tags for relative and absolute quantitation (iTRAQ) coupled with LC-MS/MS were used to screen differentially expressed proteins (DEPs) in DF-1 cells transiently transfected with EtAMA1. In total, 3953 distinct nonredundant proteins were identiﬁed and 163 of these were found to be differentially expressed, including 91 upregulated proteins and 72 downregulated proteins. The DEPs were mainly localized within the cytoplasm and were involved in protein binding and poly(A)-RNA binding. KEEG analyses suggested that the key pathways that the DEPs belonged to included melanogenesis, spliceosomes, tight junctions, and the FoxO and MAPK signaling pathways. The data in this study not only provide a comprehensive dataset for the overall protein changes caused by EtAMA1 expression, but also shed light on EtAMA1’s potential molecular mechanisms duringEimeriainfections.
Implementing High-speed Running and Sprinting Training in Professional Soccer
Authors: Beato Marco , Drust Barry , Iacono Antonio Dello
Published: December 2020

High-speed running and sprinting training play an important role in the development of physical capabilities, sport-specific performance and injury prevention among soccer players. This commentary aims to summarize the current evidence regarding high-speed running and sprinting training in professional soccer and to inform its implementation in research and applied settings. It is structured into four sections: 1) Evidence-based high-speed running and sprinting conditioning methodologies; 2) Monitoring of high-speed running and sprinting performance in soccer 3) Recommendations for effective implementation of high-speed running and sprinting training in applied soccer settings; 4) Limitations and future directions. The contemporary literature provides preliminary methodological guidelines for coaches and practitioners. The recommended methods to ensure high-speed running and sprinting exposure for both conditioning purposes and injury prevention strategies among soccer players are: high-intensity running training, field-based drills and ball-drills in the form of medium- and large-sided games. Global navigation satellite systems are valid and reliable technologies for high-speed running and sprinting monitoring practice. Future research is required to refine, and advance training practices aimed at optimizing individual high-speed running and sprinting training responses and associated long-term effects.
Chemical Modulators of Fibrinogen Production and Their Impact on Venous Thrombosis
Authors: Vilar Rui , Lukowski Samuel W. , Garieri Marco , Di Sanza Corinne , Neerman-Arbez Marguerite , Fish Richard J.
Published: December 2020

Thrombosis is a leading cause of morbidity and mortality. Fibrinogen, the soluble substrate for fibrin-based clotting, has a central role in haemostasis and thrombosis and its plasma concentration correlates with cardiovascular disease event risk and a prothrombotic state in experimental models. We aimed to identify chemical entities capable of changing fibrinogen production and test their impact on experimental thrombosis. A total of 1,280 bioactive compounds were screened for their ability to alter fibrinogen production by hepatocyte-derived cancer cells and a selected panel was tested in zebrafish larvae. Anthralin and all-trans retinoic acid (RA) were identified as fibrinogen-lowering and fibrinogen-increasing moieties, respectively. In zebrafish larvae, anthralin prolonged laser-induced venous- occlusion times and reduced thrombocyte accumulation at injury sites. RA had opposite effects. Treatment with RA, a nuclear receptor ligand, increased fibrinogen mRNA levels. Using an antisense morpholino oligonucleotide to deplete zebrafish fibrinogen, we correlated a shortening of laser-induced venous thrombosis times with RA treatment and fibrinogen protein levels. Anthralin had little effect on fibrinogen mRNA in zebrafish larvae, despite leading to lower detectable fibrinogen. Therefore, we made a proteomic scan of anthralin-treated cells and larvae. A reduced representation of proteins linked to the canonical secretory pathway was detected, suggesting that anthralin affects protein secretion. In summary, we found that chemical modulation of fibrinogen levels correlates with measured effects on experimental venous thrombosis and could be investigated as a therapeutic avenue for thrombosis prevention.
Researchers create nondestructive technique to study atomic switching
Authors: Frank Jodi Ackerman
Published: December 2020

The current-voltage measurement method for tunneling analysis was used to show that moisture supports the electrochemical mechanics of atomic switching.
A 14-moment maximum-entropy description of electrons in crossed electric and magnetic fields
Authors: Boccelli S. , Giroux F. , Magin T. E. , Groth C. P. T. , McDonald J. G.
Published: December 2020

A 14-moment maximum-entropy system of equations is applied to the description of non-equilibrium electrons in crossed electric and magnetic fields and in the presence of low collisionality, a characteristic of low-temperature plasma devices. The flexibility of this formulation is analyzed through comparison with analytical results for steady-state non-equilibrium velocity distribution functions and against particle-based solutions of the time-dependent kinetic equation. Electric and magnetic source terms are derived for the 14-moment equations, starting from kinetic theory. A simplified collision term based on the Bhatnagar–Gross–Krook operator is formulated to describe the collision of electrons with background neutrals, accounting for the large mass disparity and energy exchange. An approximated expression is proposed for the collision frequency, to include the effect of the electrons' drift velocity, showing good accuracy in the considered conditions. The capabilities of the proposed 14-moment closure to accurately capture the non-equilibrium behavior of electrons for space homogeneous problems under conditions representative of those found in Hall thrusters are demonstrated.
Electrostatic equilibria on the unit circle via Jacobi polynomials
Authors: Johnson K. , Simanek B.
Published: December 2020

We use classical Jacobi polynomials to identify the equilibrium configurations of charged particles confined to the unit circle. Our main result unifies two theorems from a 1986 paper of Forrester and Rogers.
Multi-radiators on active scattering characteristics for metal sphere model
Authors: Niu Liqiang , Xie Yongjun , Gao Jie , Wu Peiyu
Published: December 2020

In order to investigate the influence of multi-radiators, active scattering characteristics, which can be reflected by the active radar cross section (ARCS), are investigated by incorporating the multi-radiators with the radar-radiator. The proposed implementation takes advantage of the ARCS concept in terms of considerable accuracy and close to reality especially in the complex electromagnetic environment. The metal sphere model is analyzed to demonstrate the effectiveness of the proposed implementation. Several procedures are employed during the investigation. The ARCS of the metal sphere model is compared with its radar cross section with a single radar-radiator. The frequency characteristic of the ARCS for a metal sphere model with multi-radiators is calculated. The changes in the ARCS with different phases, field intensities, field polarization directions are given. An example is given to illustrate the change in the maximum detection range caused by multi-radiators. Through the results, it can be concluded that the active scattering characteristics of the metal sphere model can be significantly influenced by the multi-radiators.
Breakup characteristics of levitated droplets in a resonant acoustic field
Authors: Naka M. , Hasegawa K.
Published: December 2020

To help realize stable droplet manipulation, we present a study on the physical mechanism of interfacial instability and droplet atomization dynamics in acoustic levitation with ultrasonic phased arrays. Acoustic levitation is highly applicable in the fields of analytical chemistry and biology because container-less processing can prevent undesirable wall effects, such as nucleation and contamination resulting from the container walls. Although many studies demonstrated the atomization behavior in single-axis acoustic levitation, the breakup characteristics of levitated droplets in ultrasonic phased array levitation have been less studied. Here, we visualized the atomization behavior of ethanol, ethanol solution, and silicone oil droplets using a high-speed camera. The time evolution of the interfacial velocity of the droplets indicates a threshold for the droplet atomization. To elucidate atomization dynamics, the critical interfacial velocities of the levitated droplet immediately before its atomization are discussed and compared to the theoretical prediction based on the Kelvin–Helmholtz instability. Our experimental findings provide deeper physical insights into the levitation stability of droplets in ultrasonic phased array levitation for futuristic lab-in-a-drop applications.
A pendulum hybrid generator for water wave energy harvesting and hydrophone-based wireless sensing
Authors: Hao Congcong , He Jian , Zhang Zengxing , Yuan Yong , Chou Xiujian , Xue Chenyang
Published: December 2020

The environmental monitoring system is of great significance in marine scientific research and exploration. However, battery-operated sensors in such a system limit its working time and make maintenance difficult. Harvesting water wave energy to power these sensors becomes a promising way to overcome challenges. Herein, a pendulum type hybrid generator to scavenge wave energy and power the hydrophone is presented. The proposed pendulum structure can harvest random water wave energy from arbitrary directions sensitively. The combination of a freely rolling mode triboelectric nanogenerator (TENG) and a magnetic sphere based electromagnetic generator (EMG) provides complementary advantages and harvests wave energy in a wide frequency range. The hybrid generator is demonstrated to drive 177 LEDs and power an electronic device. At a wave driving frequency of 1.4 Hz, the output power of the EMG and TENG is 6.7 mW and 8.01 µW, respectively. A capacitor can be charged to 26 V by the hybridized generator within 200 seconds at the frequency of 1.8 Hz. The new type of hydrophone-based system realizes sustainable wireless sensing of acoustic signals and positioning information and has important application value for long-term synchronous ocean monitoring.
Demonstrating the value of herd improvement in the Australian dairy industry
Authors: Newton J. E. , Axford M. M. , Ho P. N. , Pryce J. E.
Published: December 2020

Herd improvement has been occurring since the domestication of livestock, although the tools and technologies that support it have changed dramatically. The Australian dairy industry tracks herd improvement through a range of approaches, including routine monitoring of genetic trends and farmer usage of the various tools and technologies. However, a less structured approach has been taken to valuing the realised and potential impacts of herd improvement. The present paper aims to demonstrate the value of herd improvement, while exploring considerations for undertaking such a valuation. Attractive value propositions differ among and within dairy stakeholder groups. While broad-scale valuations of genetic trends and industry progress are valued by government and industry, such valuations do not resonate with farmers. The cumulative nature of genetic gain and compounding factor of genetic lag means that long timeframes are needed to fully illustrate the value of genetic improvement. However, such propositions do not align with decision-making timeframes of most farming businesses. Value propositions that resonate with farmers and can lead to increased uptake and confidence in herd improvement tools include smaller scale cost–benefit analyses and on-farm case studies developed in consultation with industry, including farmers. Non-monetary assessments of value, such as risk and environmental footprint, are important to some audiences. When additionality, that is, the use of data on multiple occasions, makes quantifying the value of the data hard, qualitative assessments of value can be helpful. This is particularly true for herd recording data. Demonstrating the value of herd improvement to the dairy industry, or any livestock sector, requires a multi-faceted approach that extends beyond monetary worth. No single number can effectively capture the full value of herd improvement in a way that resonates with all farmers, let alone dairy stakeholders. Extending current monitoring of herd improvement to include regular illustrations of the value of the tools that underpin herd improvement is important for fostering uptake of new or improved tools as they are released to industry.
Hybrid projection methods for large-scale inverse problems with mixed Gaussian priors
Authors: Cho Taewon , Chung Julianne , Jiang Jiahua
Published: December 2020

When solving ill-posed inverse problems, a good choice of the prior is critical for the computation of a reasonable solution. A common approach is to include a Gaussian prior, which is defined by a mean vector and a symmetric and positive definite covariance matrix, and to use iterative projection methods to solve the corresponding regularized problem. However, a main challenge for many of these iterative methods is that the prior covariance matrix must be known and fixed (up to a constant) before starting the solution process. In this paper, we develop hybrid projection methods for inverse problems with mixed Gaussian priors where the prior covariance matrix is a convex combination of matrices and the mixing parameter and the regularization parameter do not need to be known in advance. Such scenarios may arise when data is used to generate a sample prior covariance matrix (e.g., in data assimilation) or when different priors are needed to capture different qualities of the solution. The proposed hybrid methods are based on a mixed Golub–Kahan process, which is an extension of the generalized Golub–Kahan bidiagonalization, and a distinctive feature of the proposed approach is that both the regularization parameter and the weighting parameter for the covariance matrix can be estimated automatically during the iterative process. Furthermore, for problems where training data are available, various data-driven covariance matrices (including those based on learned covariance kernels) can be easily incorporated. Numerical examples from tomographic reconstruction demonstrate the potential for these methods.
Physical modeling of charge transport in conjugated polymer field-effect transistors
Authors: Lee Jiyoul
Published: December 2020

Conjugated polymer field-effect transistors are expected to have considerable potential for widespread use in various applications such as flexible displays, low-cost radio-frequency tags and functional sensors for healthcare systems due to their mechanical flexibility and printing-based low-cost processability on flexible plastic substrates. Therefore, they have witnessed remarkable progress over the last three decades. However, further development of polymer field-effect transistors remains hampered because the charge transport occurring in the active semiconducting polymer layers has not been understood adequately and the device physics has not yet been established completely. This topical review summarizes the physical charge transport models of polymer semiconductors that have been proposed so far and discusses the advantages and disadvantages of each model. Accordingly, the process of analyzing the experimental results by employing the appropriate physical charge transport model is investigated to ultimately facilitate the rational design of advanced semiconducting polymers as well as the fabrication of enhanced organic devices.
Synthesis and characterization of MWCNT-covered stainless steel mesh with Janus-type wetting properties
Authors: Karthikeyan Adya , Kasparek Evelyne , Kietzig Anne-Marie , Girard-Lauriault Pierre-Luc , Coulombe Sylvain
Published: December 2020

Various multi-step methods to fabricate Janus membranes have been reported in literature. However, no article so far reports the durability of the Janus membranes when exposed to liquids. We report on a novel method to fabricate a Janus-type multi-walled carbon nanotubes (MWCNT)-covered stainless steel (SS) mesh, which retains dual-wetting properties even after exposure to water for 540 d. The MWCNTs are grown directly on stainless steel mesh coupons by chemical vapor deposition using acetylene as the carbon source, and are then plasma functionalized using an ammonia-ethylene gas mixture to achieve dual-wettability. We found by x-ray photoelectron spectroscopy that the MWCNTs on the top face of the novel Janus MWCNT-SS mesh, which was directly exposed to the plasma, are coated by a plasma polymer rich in nitrogen-containing functional groups, while the MWCNTs on the bottom face are almost devoid of the plasma polymer coating. Atomic force microscopy studies confirmed that the surface roughness of the bottom face of the mesh is lower than the minimum roughness that allows the capillary ingress of water to sustain its superhydrophobic behavior. In addition, scanning electron microscopy studies also confirmed that the MWCNTs on the bottom face of the treated MWCNT mesh are vertically aligned compared to the MWCNTs on the top face of the mesh. The vertically aligned dense MWCNT forest on the bottom face attributes to its superhydrophobic nature.
Understanding ambipolar transport in MoS2 field effect transistors: the substrate is the key
Authors: Mootheri Vivek , Leonhardt Alessandra , Verreck Devin , Asselberghs Inge , Huyghebaert Cedric , de Gendt Stefan , Radu Iuliana , Lin Dennis , Heyns Marc
Published: December 2020

2D materials offer a pathway for further scaling of CMOS technology. However, for this to become a reality, both n-MOS and p-MOS should be realized, ideally with the same (standard) material. In the specific case of MoS2 field effect transistors (FETs), ambipolar transport is seldom reported, primarily due to the phenomenon of Fermi level pinning (FLP). In this study we identify the possible sources of FLP in MoS2 FETs and resolve them individually. A novel contact transfer technique is used to transfer contacts on top of MoS2 flake devices that results in a significant increase in the hole branch of the transfer characteristics as compared to conventionally fabricated contacts. We hypothesize that the pinning not only comes from the contact-MoS2 interface, but also from the MoS2-substrate interface. We confirm this by shifting to an hBN substrate which leads to a 10 fold increase in the hole current compared to the SiO2 substrate. Furthermore, we analyse MoS2 FETs of different channel thickness on three different substrates, SiO2, hBN and Al2O3, by correlating the p-branch I
ON/I
OFF to the position of oxide defect band in these substrates. FLP from the oxide is reduced in the case of Al2O3 which enables us to observe ambipolar transport in a bilayer MoS2 FET. These results highlight that MoS2 is indeed an ambipolar material, and the absence of ambipolar transport in MoS2 FETs is strongly correlated to its dielectric environment and processing conditions.
Interface-enhanced superconductivity in multi-grain (FeSe)η(SrTiO3)1-η composites
Authors: Zhang Huimin , Dong Wenfeng , Meng Qing-Long , Yin Nan , Liu Zhengmao , Lu Xiaowei , Ge Binghui , Li Yuanzhao , Shi Quan , Wang Lili , Xue Qi-Kun , Jiang Peng , Bao Xinhe
Published: December 2020

Interface superconductivity, realized in multiple artificial crystalline heterostructures, is one of the most exciting directions to search for high-temperature superconductivity. In this work, we prepare bulk (FeSe)
η
(SrTiO3)1−η
multi-grain composites by a simple facile liquid-phase compaction method using a spark-plasma-sintering technique. Combining transmission electron microscopy/scanning electron microscopy and x-ray diffraction investigations, we demonstrate that the composites consist of micron-scale SrTiO3 grains surrounded by [001]-compressed β-FeSe grains. Transport measurements for the composites with FeSe mole fraction η > 0.06 reveal that two superconducting channels, one T
c ∼ 13 K phase from FeSe/SrTiO3 interfaces and another T
c ∼ 7 K phase from FeSe grains, cooperatively induce macroscopic superconducting behavior with isotropic upper critical fields above 40 T. This work points out a straightforward method to enhance T
c in the multi-grain (FeSe)
η
(SrTiO3)1−η
composites by reducing the crystalline grains to nanoscale and finely tuning the stoichiometries of FeSe and SrTiO3.
Ultra-high optical nonreciprocity with a coupled triple-resonator structure
Authors: Cao Zhen , Xie Yi Fei , He Bing , Lin Qing
Published: December 2020

Optical transmission nonreciprocity as a widely investigated phenomenon is essential to various applications. Many sophisticated mechanisms have been proposed and tested for achieving the optical nonreciprocity on integrated scale, but the technical barriers still exist to their practical implementation. To have an ultra-high transmission nonreciprocity, we consider a simple physical mechanism of optical gain saturation applied to a structure of three mutually coupled cavities or fiber rings. The gain saturation processes in two of its components creates a significantly enhanced optical nonreciprocity that satisfies the requirements for the realistic applications. The structure enjoys two advantages of its wide working bandwidth and the flexibility in choosing its components. Moreover, it is possible to apply the structure to a faithful and non-reciprocal transmission of broadband pulse signals. The structure may considerably relax the constraints on the integrated photonic circuits based on the current technology.
Effect of dimensional parameters on the seismic performance of circular CFST columns
Authors: Reshma S , Bushra M A
Published: December 2020

Due to the expansion of cities and increase in population, the need for construction of high rise buildings becomes more essential in the society. As earthquakes are of the greatest damaging natural hazards to the buildings, the design and construction of structures which are capable of resisting the adverse effects of earthquakes become necessary. Concrete Filled Steel Tubes (CFSTs) are the steel tubular sections in-filled with concrete and with a composite action. CFSTs are becoming a popular solution for structures located in seismic areas, due to their high strength, excellent ductility and large energy absorption capacity. This study was mainly concentrated to find out the effect of dimensional parameters on the seismic performance of CFSTs. Width - thickness ratio (D/t) and slenderness ratio (L/D) were taken as two parameters and the study was carried out using circular CFST buildings. It was observed that, there will be a particular limit for D/t and L/D ratio upto which the thickness and diameter of the CFSTs can be decreased. At that point the building will show a better seismic performance.
Mechanical properties of blended cement mortar systems exposed to ammonium chloride environment
Authors: Babu Sheba , Sahad Mohammed , Vijeesh K P , Syamjith C K , Raneesh Mohammed , Ramaswamy K P , Nazeer M , Thowsif Mohammed
Published: December 2020

There are number of areas where cement composites can be exposed to ammonium based compounds such as agricultural land, chemical fertilizer plants, waste waters, polluted and industrial environments, which can induce severe and premature deterioration of concrete systems. Based on the review of literature, the most common and deleterious ammonium based salts were found to be ammonium nitrate, ammonium chloride and ammonium sulphate. The cementitious systems with Ordinary Portland Cement (OPC) may be attacked easily by these ammonium based chemicals as the OPC hydrates such as Portlandite and C-S-H gel are considered to be unstable in these aggressive media. Thus, it is necessary to understand the alteration kinetics of cementitious systems and the effectiveness of Supplementary Cementitious Materials (SCMs) in improving the resistance when exposed to ammonium based environments for develpoing more durable and sustainable concrete systems. The aim of this experimental study was to investigate the durability aspects in terms of the changes in mechanical properties of cement mortar specimens made with OPC and different combinations of various Supplementary Cementitious Materials (SCMs) exposed to ammonium based salt solution prepared using chemical grade ammonium chloride (NH4Cl). The mortar specimens were exposed to ammonium chloride solution in two different concentrations (1.25 M and 2.5 M) for a maximum exposure duration of two and half months. The SCMs used for the study include Class F Fly ash (FA), Ground Granulated Blast Furnace Slag (GGBS), and Silica fume (SF). The changes in the mechanical properties were evaluated on the basis of visual assessment, depth of penetration, changes in the compressive strength, changes in Ultrasonic Pulse Velocity (UPV) and relative dynamic modulus of elasticity. From all the test results, it can be concluded that the ternary blended mix with OPC, GGBS and Silica fume (OPC-GGBS-SF) has higher resistance to ammonium chloride attack. The results stress the need to include SCMs and the importance to tailor make the concrete for structures exposed to aggressive environment like ammonium chloride.
Analytical study on the behaviour of beam-column joints made of electric arc furnace concrete
Authors: Gowri Krishna S R , Ambi Rekha
Published: December 2020

The advancement of the construction industry towards using recycled materials has substantially reduced the consumption of natural resources. Electric Arc Furnace (EAF) slag is the by-product obtained from the production of steel and is procured after the separation of molten steel from impurities. In this paper, the impact of EAF concrete on the structural behaviour of beam-column joints and the resisting mechanism of these joints are evaluated using ANSYS software. One joint made with conventional concrete and two joints made with EAF concrete were analysed subjected to incremented loading. The results indicate that EAF concrete exhibits better structural performance than conventional concrete in terms of the ultimate load attained by the joint in the failure condition.
A parametric study on fatigue life of plate girder railway bridge with varying velocity of rolling stock
Authors: Ramzi Nasar K , Althaf M , Hisham Ajmal P C
Published: December 2020

It is important to measure the fatigue life of a structure as it helps in finding the probable life of a structure before its failure. It also helps in making cost effective decision on existing structure regarding replacement or rehabilitation in time. In this study deterministic approach is used for the estimation of fatigue life of a plate girder railway bridge. Finite element analysis is carried out using software to find the critical region of fatigue failure and the stress developed there. Number of cycles of different stress range during the movement of train is evaluated with the help of S-N curve. The S-N curve is selected based on type of welds and type of stress considered. Rain flow counting method is used for evaluating the number of cycles corresponding to each stress range. The fatigue damage is then evaluated by using Palm Miner damage accumulation rule and corresponding fatigue life is evaluated. The fatigue life corresponding to different velocity of train ranging from 30 kmph to 140 kmph is generated similarly and compared to find the influence of velocity of moving load on fatigue life of structure.
Optimization of high strength concrete with construction and demolition waste
Authors: Geetha S , Selvakumar M , Muthulakshmi S
Published: December 2020

The development in the Infrastructure Sector has led to a revolution in the Construction Industry with fast track projects. Hence the use of prefabricated construction is gaining importance in India in the recent days. The structural elements like beams, columns and wall panels are fabricated in a factory and assembled at the site. The concrete used in the fabrication of these members are conventional concrete with density range 2400-2500 kg/m3. The transport, handling and erection of these members involve large machineries. Moreover due to the use of conventional concrete the self weight of the structure also increases leading to large column size and foundations. Hence this work is based in optimizing reactor powder with mineral admixtures, construction and demolition waste and steel fibres that can be used in precast construction. The compressive strength achieved is 63.12 Mpa, flexural strength is 6.21 and tensile strength is 6.38MPa. Rapid chloride penetration test (RCPT) was done to test the durability of the concrete and it was found to be 469 coulombs which proved it to be resistant to chloride penetration.
Theoretical Foundations of Water-Conducting Belt Design for Wide Coverage Sprinklers Using Numerical Simulation
Authors: Skvortsov A. A. , Zhuravleva L. A.
Published: December 2020

Improvement of wide-coverage sprinkler technical level requires provision of high irrigation productivity and quality with the minimum cost of construction, rational use of water and energy. It is necessary to maintain the required flow-pressure characteristics regardless of sprinkler external operating conditions and the length of the water supply belt. The article discusses the possibility of mathematical modeling application for a wide sprinkler design. The studies showed that during the calculation it is possible to get by with the finite equations without resorting to the differential equations of fluid motion theory with variable mass. The obtained dependences served as the basis for the development of water-conducting belt calculation methods for a wide-sprinkler.

A numerical simulation of the water supply belt operation of the KASKAD sprinkler is presented with standard values for the pipeline diameters and the variable length of the sprinkler. Numerically obtained graphs of the flow rate and the required pressure dependences on water supply belt length for two design options: with a sector end sprinkler and an end longrange sprinkler operating from a booster pump. By eliminating the length of the water supply belt for the considered two design options, they designed the flow-discharge characteristics of the sprinkler. They presented an example of a constructive solution selection for the water-conducting belt of a sprinkler according to flow-pressure characteristics.
Digital Photogrammetry for Fruit Disease Identification
Authors: Saranya G , Vidhya B , Dhivya Dharshini V , Divya Kamala Bharathi M
Published: December 2020

Nowadays horticulture takes about 25% of the agriculture enterprise that has a excellent impact in the fruits field. Effective growth of crops and improved field culture must be incorporated to insure honest yield. To achieve that farmers need an environment friendly monitoring system. Farmers find it difficult to discover fruit ailment and its cause. Also, fruits are more prone to get infection in the course of cultivation, due to changing environmental condition and climate. The previous method concerning detecting fruit ailment was once more time ingesting and failed to supply information regarding the type of disease. Using the proposed fruit ailment discovery system, the agriculturist can determine the kind of the disease, and find preventive measures or suggestions. Image processing techniques are used for the enhancement of the received images. Then, convolution neural network has been used to make the model learn and classify the fruits and its disease. This system will benefit farmers across India.
Hardware Design and Implementation of Microcontroller Based Reduced Switch Multilevel Inverter Topology for Harmonic Studies Using MRPWM
Authors: Uma D , Augusti Lindiya S , Lindiya  , Subashini N , Vijayakumar A
Published: December 2020

Multilevel inverter (MLI) is the recent advancement in power electronics which employed to synthesize a high-quality output voltage waveform. This paper focuses on developing a single phase modified nine-level inverter with the reduced number of switches for improving the quality of output voltage waveform. Single carrier and multireference Pulse Width Modulation (PWM) technique is utilized for generating the switching pulses. The proposed topology consists of a single DC source, level generation part (balancing capacitor and bidirectional switches) and polarity generation part (H-Bridge). The operation of the proposed topology is examined for generating 9-level output voltage using MATLAB/SIMULINK. The result of the proposed topology is verified through laboratory-based prototype model. For experimental setup, the switching pulses are generated by PIC16F877A microcontroller. This proposed lab experimental and simulation can be used to study the value of %THD at output side of the inverter.