bluuebunny/crossref_metadata_2025 huggingface dataset:
Academic Social Networking Sites (ASNS) as Platforms for Knowledge Sharing Among the Scholarly Community
Authors: Masenya Tlou Maggie
Published: November 2020

As the world becomes more networked through social media like Facebook, Twitter, etc., the academic world has also developed its own online Academic Social Networks Sites (ASNS), such as ResearchGate, Academia.edu, Google Scholar, Mendeley, Zotero, and Methodspace, just to name a few. Academics and researchers are using these platforms as alternative ways to share and disseminate their research to a wider audience to increase the visibility of their academic output, to support the sharing of data set and to connect with other scholars. However, ASNS are not only enabling researchers to form networks, but are also opening up avenues for them to interact, share ideas and knowledge, and engage in discussions that relate to research practices. The aim of this study was therefore to examine the use of ASNS by researchers and academics and its importance in knowledge sharing. Data collection was largely based on a critical review of literature relating to the use of ASNS for knowledge sharing by academics and researchers. The findings revealed that most academics and researchers are faced with many challenges that hinder the effective use of these network sites. The practice of uploading articles on ASNS has become a contentious issue with publishers claiming infringement of copyright agreements on the part of researchers. Copyright and intellectual property issues thus need to be addressed. The study also observed that, in some instances, academics and researchers were not fully involved in collaborative with other scholars. Collaboration amongst researchers is therefore recommended as it stimulates creativity and helps in addressing this complexity of research. This study, therefore, recommends that researchers can address some of ASNS challenges if they leverage on these factors because resolution of complex research problems issues can only be achieved through cross disciplinary collaboration and this can also pave the way for knowledge sharing in practice.
Smart Libraries in the Google Glass Era for Millennial Users
Authors: Sane Priyanka V. , Prakashe Veena A.
Published: November 2020

The motivation behind this chapter is to talk about the rising and imaginative advancements which coordinate to shape savvy libraries. Smart libraries are the new age libraries, which work with the amalgamation of shrewd advances, brilliant clients, and savvy administrations. The literature search compared different watchwords like smart libraries, internet of things (IoT), data mining, artificial intelligence (AI), etc. Now the time has come that libraries need to adopt the “smart library” culture due to changing demands of the patrons and the different services offered by the libraries to the patrons. The chapter features the developing new cool latest technologies that are used in different brilliant libraries and how they impact the productivity of libraries as far as patrons, administrations, and innovative coordination. The chapter attempts to feature the present advancements in the shrewd library set-ups for the productive working of library set-ups.
The Role of Digital Libraries in Supporting Open Distance E-Learning
Authors: Tsabedze Vusi W.
Published: November 2020

This chapter aims to discuss the potential of digital libraries to offer unparalleled resources for supporting open distance e-learning (ODeL). This chapter addresses and discusses such features as what is meant by ODeL and how it can be supported by the library and the functionality of the digital library, and how ODeL resources are included and organised in the digital library environment. The chapter explores the advantages of digital libraries for ODeL and the types of learning that can be supported by digital libraries. There is surely an interest in the usage of electronic resources for teaching, learning, and research, but this appears to be matched by a lack of awareness of how best to assimilate these resources into ODeL. The chapter provides valuable insight into the role and influence of digital libraries and e-resources on ODeL.
Information Technology Skills and Competencies for Academic Library Staff
Authors: Dube Tinyiko Vivian
Published: November 2020

Academic libraries are now enduring a substantial shift, which is influenced by the advancement of information technology (IT) that has drastically changed the operating system of academic libraries. The changes have impacted significantly on the skills and competencies required of library staff. This chapter shed light on the background of modern academic libraries, the IT tools used by various academic libraries (for both remote clients and library staff) around the world to provide and access information resources and/or library and information services (LIS) to meet the information needs of remote clients. IT is becoming a tool in modern academic libraries designed to facilitate library operations to meet the information needs of academic library clients. In light of this, library staff is obliged to be equipped with IT skills and competencies to assist the institution to achieve its objectives by supporting teaching, learning, and research.
Community Voices the Need to Write, Record, and Disseminate Research Findings From the Grassroots
Authors: Sutherland Stewart
Published: November 2020

Research on Indigenous people has moved from looking in on a subject to having the subjects as research partners, alongside academic researchers. Community-based research has a number of ethical requirements that means research partners have a voice. How this voice is captured, stored, and distributed is of great importance. For many publishers, academic or institutional, the voice of the layman or grassroots organisations are not valued. This results in much work going unpublished and hence being poorly archived. Often the stories of community are told with an earthy richness that is lacking in academic writing. This is partly due cultural storytelling, not writing to the rigidity of academia. This chapter will discuss a variety of methods that can be employed to raise the voice of community research partners who may not be academics and academically minded. However, the stories of our partners are important and are just as valid as those of the academic researcher.
Knowledge Transfer Among Academics in Higher Education Institutions
Authors: Enakrire Rexwhite Tega
Published: November 2020

In this fourth industrial revolution, knowledge transfer is essential among experienced academics for cross-fertilisation of ideas. Academics or colleagues in higher education institutions (HEIs) should harness and share their intuitive knowledge, skills, and experience for better service delivery. The rationale attributes to the decrease in skilled professionals in academia, technophobia, age, and language barriers. The issues of physical and mental ability, communication barrier, lack of trust, policies affirmation and organisational culture not supportive of knowledge transfer in HEIs were identified. A flair for things such as the consideration of who must capture new knowledge for organisational sustainability; suitable infrastructural facilities that can be used to gather, store and distribute information and knowledge; uncertainty of diverse economic and political influences; and limited budgetary allocation was believed to also affect knowledge transfer among academics. The qualitative research approach makes use of interpretive content/document analysis harvested from different databases to support the arguments regarding what, why and how knowledge transfer is central to every human endeavour. Findings indicate that inter-and intra-organisational knowledge transfer and organisational culture are the oil that lubricates organisational growth of academia. The study found that tacit to tacit type of knowledge, skills, and experiences were mostly transferred through communication through face-to-face discussions, online platforms, emails, and LinkedIn. Formal and informal processes of knowledge creation, application, peer-to-peer, and teamwork training approaches (coaching, mentorship, networking, and work shadows) and the use of certain tools (social and collaborative tools, video, chat, intranet, blog, posting, forum and mobile devices) were significant in this era of digital technologies. The study recommends succession planning for knowledge transfer, an attitude of trust, cooperation and teamwork, training, communication, and lifelong learning to enhance knowledge transfer among academics.
Exploring Learners' Attitudes Towards Technology-Enhanced Flipped Language Instruction
Authors: Lee Lina
Published: November 2020

The article reports on a study that explored the affordances and challenges of the flipped classroom model for an advanced language course, involving the implementation of a four-skill integration approach and the use of various digital tools. Eighteen advanced language students participated in the study over the course of one semester. Students carried out a variety of online assignments using self-access learning modules in Canvas to prepare them for in-class activities. Data from post-surveys and focus group interviews along with the student coursework reveal that students had a positive attitude towards the flipped model because it gave them agency over their own learning and engaged them in meaningful interactions with their peers. The study suggests that well-designed tasks are essential, and that instructor scaffolding is needed to guide students in learning course content. The study contributes a new model of flipped instruction that facilitated L2 development in an effective manner.
Internet Gaming Disorder and Its Relationships With Student Engagement and Academic Performance
Authors: Samaha Maya , Hawi Nazir
Published: November 2020

Recently, the research community increased its investigations of the student engagement construct in association with learning and academic success. Some scholars linked student engagement to higher academic performance, higher retention rates, and lower delinquency rates. However, the spread of gaming among learners is thought to hinder student engagement. This study attempts to fill a gap in the literature by investigating the association among gaming disorder, student engagement, academic performance, and gamer-related characteristics, in a tertiary context on a sample of 345 university students using the internet gaming disorder (IGD-20) test and an 18-item assessment of student engagement based on the National Survey of Student Engagement. Student engagement was significantly negatively predictive of gaming disorder, whereas the latter was significantly negatively predictive of cumulative GPA. The implications of the findings for future research and recommendations are discussed.
A Novel Verification Protocol to Restrict Unconstitutional Access of Information From Smart Card
Authors: Sahu Ajay Kumar , Kumar Ashish
Published: November 2020

The services of the internet play an essential part in the daily life of the users. So, safety and confidentiality of the information are to be maintained to preserve user conviction in various services offered by network. The two-factor-based password verification techniques are used between remote server and legitimate users for verification over insecure channel. Several protocols have been suggested previously claiming their simplicity, privacy, safety, and robustness. The authors proved that their enhanced protocols are vulnerable to different attacks on the network and permit only authenticated users to update their password preserving traceability and identity. Analysis shows that no scheme has fulfilled all the security requirements and achieved entire goals. Therefore, in this article, a scheme has been presented to overcome these issues in the previous schemes to resist illegal access leading to misuse and achieve all the security requirements and goals. The safety analysis of the presented scheme has confirmed its performance in terms of reliability and safety.
Detection of Suspicious or Un-Trusted Users in Crypto-Currency Financial Trading Applications
Authors: Mittal Ruchi , Bhatia M. P. S.
Published: November 2020

In this age, where cryptocurrencies are slowly creeping into the banking services and making a name for them, it is becoming crucially essential to figure out the security concerns when users make transactions. This paper investigates the untrusted users of cryptocurrency transaction services, which are connected using smartphones and computers. However, as technology is increasing, transaction frauds are growing, and there is a need to detect vulnerabilities in systems. A methodology is proposed to identify suspicious users based on their reputation score by collaborating centrality measures and machine learning techniques. The results are validated on two cryptocurrencies network datasets, Bitcoin-OTC, and Bitcoin-Alpha, which contain information of the system formed by the users and the user's trust score. Results found that the proposed approach provides improved and accurate results. Hence, the fusion of machine learning with centrality measures provides a highly robust system and can be adapted to prevent smart devices' financial services.
Robustness and Predictive Performance of Homogeneous Ensemble Feature Selection in Text Classification
Authors: Mehta Poornima , Chandra Satish
Published: November 2020

The use of ensemble paradigm with classifiers is a proven approach that involves combining the outcomes of several classifiers. It has recently been extrapolated to feature selection methods to find the most relevant features. Earlier, ensemble feature selection has been used in high dimensional, low sample size datasets like bioinformatics. To one's knowledge there is no such endeavor in the text classification domain. In this work, the ensemble feature selection using data perturbation in the text classification domain has been used with an aim to enhance predictability and stability. This approach involves application of the same feature selector to different perturbed versions of training data, obtaining different ranks for a feature. Previous works focus only on one of the metrics, that is, stability or accuracy. In this work, a combined framework is adopted that assesses both the predictability and stability of the feature selection method by using feature selection ensemble. This approach has been explored on univariate and multivariate feature selectors, using two rank aggregators.
Influence of Alumina Particles on Tribology of Autocatalytic Ni-P Coatings at High Temperature
Authors: Kundu Sanjib , Das Suman Kalyan , Sahoo Prasanta
Published: November 2020

The present work considers the effects of incorporation of hard Al2O3 particles on the structure, microhardness, and tribological behavior of electroless Ni-P coatings at room temperature and elevated temperature. Ni-P (9% P) coating shows a typical amorphous structure that changes to a mixture of nanocrystalline and amorphous structure due to the addition of alumina particles. The incorporation of Al2O3 particles is found to enhance the overall hardness and wear resistance of the Ni-P coating. Exposure to high temperature during tribological tests acts as brief heat treatment, initiating microstructural changes in the coating which further increases the hardness of the deposit. The scanning electron micrograph of the worn surface of the coating reveals both abrasive and adhesive wear phenomena governing the wear mechanism at elevated temperature. The development of the oxide layer is another important characteristic of the coatings examined under high temperatures (around 500°C).
Numerical Analysis of the Fluid Flow Behavior in the Plain Journal Bearing at Textured and Not Textured Surface
Authors: Nadia Bendaoud , Kadda Mehala
Published: November 2020

Hydrodynamic plain bearings are components that provide the guiding in rotation of rotating machines, such as turbines, the reactors. This equipment works under very severe operating conditions. In order to improve the hydrodynamic performance of these rotating machines, the industrialists specialized in the manufacture of hydrodynamic bearings have designed a bearing model with its textured interior surface. The numerical analysis is carried out to study the for both plain bearings types with a textured a non-textured surface thus to see the improvement of the plain bearing hydrodynamic performances, as well as the fluid flow behavior in motion. The analysis is performed by solving the continuity equation of Navier-Stokes, by the finite volume method, using CFD code. The numerical results show that the most important hydrodynamic characteristics such as pressure, minimal film thickness, friction torque, leakage flow, are significant for the textured plain bearing under rotational velocity of 6000rpm and radial load 10000N compared to obtained for a non-textured plain bearing.
Microstructural and Fractographic Analysis of CuAlNi Shape Memory Alloy before and after Heat Treatment
Authors: Ivanić Ivana , Gojić Mirko , Kožuh Stjepan , Kosec Borut
Published: November 2020

The paper presents comparison of microstructure and fracture surface morphology of the CuAlNi shape memory alloy (SMA) after different heat treatment procedures. The investigation was performed on samples in as-cast state and heat treated states (solution annealing at temperatures of 850 °C / 60’ / H2O and 920 °C / 60’ / H2O along with tempering at two different temperature 150 °C / 60’ / H2O and 300 °C / 60’ / H2O). The microstructure of the samples was examined by optical (OM) and scanning electron microscope (SEM) equipped with device for EDS analysis. The obtained fracture surfaces were examined by SEM. Optical and scanning electron microscopy showed martensitic microstructure in all investigated samples. However, the fractographic analysis of samples after tensile testing reveals significant changes in fracture mechanism. In both solution annealed states the results shows transgranular type of fracture, but after tempering at two different temperatures the difference is obvious. After tempering at 150 °C, along with transgranular type of fracture appear some areas with intergranular type of fracture. After tempering at 300 °C, fracture surface reveals completely intergranular type of fracture.
Size Effect in Plastic Deformation and Failure of Metallic Glasses
Authors: Miškuf Jozef , Csach Kornel , Juríková Alena , Demčáková Mária , Demčáková Mária , Ocelík Václav
Published: November 2020

Depending on the composition and structure of metallic glasses cells with the dimensions in the range from tenths nanometers to tenths micrometers were observed on the ductile fracture surface. The variation in dimple size was compared with the serrations presented on the loading curve at the nanoindentation of the metallic glasses with different compositions. Higher instantaneous deformation can be connected with simultaneous shearing at more suitable shear band configurations. The cell morphology with the various cell sizes is observed at the failure of the metallic glasses. At the failure of high strength metallic glasses, the cells are formed in short time due to the release of high amount of stored elastic energy. In this case the uniform cell morphology with the cell size of about 20 nm is observed.
Analysis of Causes of Defects Appearance in Wire Drawing
Authors: Švejcar Jiří , Juliš Martin , Klakurková Lenka , Gejdoš Pavel , Zikmund Tomáš
Published: November 2020

In the manufacture of wires designed for the welding of low-alloy fine-grain steels, multiple internal discontinuities appear during some periods that are the cause of major failures (cracking) of the wires. To establish the causes of this phenomenon, a complex analysis was performed making use of light and electron microscopy, metallography, microfractography, computerized tomography and hardness measurement. The analysis revealed that wire cracking in course of wire drawing was due to the superposition of the effects of an inappropriate structure of the initial intermediate product (the presence of polyhedral grains of hard bainitic phase) and unsuitable conditions of the forming process.
Metallographic Analysis of Stainless Steel Inner Shaft of Centrifugal Pump
Authors: Gejdoš Pavel , Klakurková Lenka , Juliš Martin
Published: November 2020

The paper focuses on the metallographic analysis of the damaged inner shaft of a centrifugal pump with a magnetic clutch. This pump was used for the pumping of viscous suspensions. The damaged part of the centrifugal pump was made of stainless steel and transmitted power from the magnetic clutch to the impeller of the pump. The pump was overhauled by the Manufacturer after ten years of routine work. Slightly worn parts of the pump, including the inner stainless steel shaft, were replaced by the Manufacturer according to the preserved documentation. The overhauled pump failed after two days of running in the original conditions. The problematic is solved by an analysis of three used inner shafts with the aid of a metallographic analysis of the microstructure of the material, using light microscopy and scanning electron microscopy, and an EDS microanalysis of the chemical composition and hardness measurements.
Influence of Cyclic Loading on the Internal Friction Measured on Magnesium Alloys AZ31, AZ61 and AZ91
Authors: Uhríčik Milan , Dresslerová Zuzana , Palček Peter , Oršulová Tatiana , Hanusová Patrícia
Published: November 2020

The article is aimed on the analysis of the influence of cyclic loading on the internal friction measured on magnesium alloys, especially AZ31, AZ61 and AZ91, after homogenization annealing. Microplastic processe and dissipation of energy within the alloys are evaluated and investigated by internal friction measurements. In experimental measurements resonance method was used, which is based on continuous excitation of oscillations of specimens. Measurements were performed at final excitation voltages of 5 V, 6 V and 7 V.
Influence of Oxide Dispersoids on the Structure Development of Copper Nanocomposite Prepared by Spark Plasma Sintering Technology
Authors: Szabo Juraj , Ďurišinová Katarína , Milkovič Ondrej , Ďurišin Juraj
Published: November 2020

Dispersion strengthened Cu composites are studied over recent years to find an optimum processing route to obtain a high strength, thermal-stable copper alloy designed for modern applications in electrical engineering. The experimental Cu–4Al2O3–1MgO material was prepared by in situ thermo-chemical technique and mechanical milling followed by spark plasma sintering (SPS). The study analyses the influence of the Al2O3 and MgO secondary phases on strengthening the copper matrix. Microstructure of the composite was studied by X-ray diffraction analysis, scanning and transmission electron microscopy. The sintered microstructure shows a grain size distribution characterized by ultrafine grains/twins embedded inside the matrix of nanocrystalline grains. The microstructure is thermal stable up to 900 °C due to the dispersed alumina nano-particles that effectively strengthen crystallite/grain boundaries during the SPS process and annealing of the sintered compact at elevated temperatures. On the other hand, the coarsened MgO particles are responsible for ultrafine grains/twins formation. The obtained microstructure is important for practical utilization of the material because this structure is characterized by a good combination of strength and ductility.
Microstructure Characteristics, Tribology and Nano-Hardness of HVOF Sprayed NiCrRe Coating
Authors: Ivor Michal , Medved Dávid , Chmielewski Tomasz , Tobota Konrad , Pietrzak Katarzyna , Chmielewski Marcin , Halama Maroš , Kottfer Daniel , Dusza Jan
Published: November 2020

The high-velocity oxy-fuel technique (HVOF) was used to produce dense NiCrRe coating on boiler steel substrate with a minimal amount of oxide impurities and low porosity. Microstructure analysis, tribology and nano-hardness measurement have been realized with the aim to characterize the systems. The microstructure was studied using scanning electron microscopy and Energy-dispersive X-ray spectroscopy. Tribological characteristics have been studied under the dry sliding condition at applied loads of 5, 10 and 20 N using the ball-on-flat technique with SiC ball at room temperature. Nano-hardness was investigated in continuous stiffness measurement (CSM) mode, the indentation depth limit was 1500 nm. Microstructure analyses proved that the HVOF sprayed layer, with a thickness approximately 870 µm, contains a relatively low volume fraction of porosity with a chemical composition based on Nickel, Chromium, with white areas of Rhenium. The wear rate of the coating is significantly lower than the wear rate of 16Mo3 steel. The average values of indentation modulus and hardness were EIT = 237.6 GPa and HIT = 6.3 GPa, respectively.
The Effect of Heat-Treatment on the Phase Stability of Fe-28Al-15Si-2Mo Alloy
Authors: Vodičková Věra , Švec Martin , Hanus Pavel , Pazourková Prokopčáková Petra
Published: November 2020

The structures of Fe-28Al-15Si-2Mo iron aluminide in as cast state and in three states after heat-treatments were investigated for the verification of secondary phases stability. Short-term (at 1000 °C for 24 h and at 1200 °C for 2 h) as well as long-term (at 800 °C for 100 h) annealing were performed. Molybdenum addition enhances the high-temperature mechanical properties due to solid solution strengthening, however the mechanism of hardening could be modified (to solid solution strengthening + strengthening by incoherent precipitates) by another alloying element (f. e. Si or C). The phase compositions of alloys were described by means of scanning electron microscopy equipped with energy dispersive analysis. The complex Fe-Si-Mo carbides were found in the structure. The bulk hardness measurement and image analysis were performed for the verification of secondary phase stability. Particles became coarse with increasing temperature of annealing.
The Effect on the Interface and Reliability of SiC MOS by Ar/O2 Annealing
Authors: Luo Zhi Peng , Wan Cai Ping , Xia Jing Hua , Jin Zhi , Xu Heng Yu
Published: November 2020

In this paper, SiC MOS capacitors were fabricated and annealed in Ar/O2 = 9:1 ambient with different temperature, and the annealing effects on the reliability and performance of SiC MOS capacitance were investigated. We found that annealing in Ar/O2 ambient is capable to improve the reliability of gate oxide. When annealing in higher temperature, defects near SiO2/SiC interface are reduced, but the gate reliability deteriorated. It is difficult to obtain the best performance and reliability under the same conditions. There is a trade-off between Dit and reliability to adjust the annealing conditions.
Inserting a AlN Electron Blocking Layer for InGaN/GaN Blue Light-Emitting Diodes
Authors: Zuo Wan Sheng , Niu Yin Xi , Yang Liu , Chi Xiu Zhen , Liu Jin Jin , Zhang Xiao Hong
Published: November 2020

In this study, the advantages of the AlN electron blocking layer (EBL) for InGaN/GaN blue light-emitting diodes (LEDs) were investigated. The LEDs with the AlN EBL exhibited better optical performance over a wide range of carrier concentration due to the suppression of electron overflow. Furthermore, the AlN EBL with a thicker last barrier layer was investigated. The thicker last barrier layer was used to enhance Electrostatic Discharge (ESD) characteristic by the better current spreading effect.
Broadband Ultraviolet Photodetector Based on Graphene/β-Ga2O3/GaN Heterojunction
Authors: Zeng Chun Hong , Ma Yong Jian , Zhang Bao Shun , Xu Ya Meng , Kong Mei
Published: November 2020

Broadband ultraviolet (BUV) photodetectors are widely used in military and civil fields. A high performance BUV photodetector based on graphene/β-Ga2O3/GaN heterojunction is proposed and realized by semiconductor micro-fabrication techniques in this paper. The β-Ga2O3 and GaN films are grown by metal organic chemical vapor deposition (MOCVD), and the graphene is also used as a transparent electrode. The device exhibits a broad response band from 230 nm to 368 nm with responsivity exceeding 0.4A/W at -5 V bias voltage and a peak responsivity of 0.53 A/W at 256 nm. These performances can be attributed to the internal gain mechanism of graphene/β-Ga2O3/GaN heterojunction and the optical properties of graphene. Our work provides an efficient method to realize a high-performance BUV photodetector for photoelectric applications.
Optimal Design of Large Signal Performance of AlN/GaN Hetero-Structural IMPATT and MITATT Diodes
Authors: Wu Ping , Wei Wen Sheng , Zheng Jun Ding , Yang Wei Bo , Li Chang , He Ming Chang , Wan Yi
Published: November 2020

Hetero-structure of AlxGa1-xN/GaN exhibits important applications in high frequency and large power devices. In this paper, AlN/GaN is adopted to optimal design the large power impact avalanche transit time (IMPATT) and mixed tunneling avalanche transit time (MITATT) diodes operating at the atmospheric low loss window frequency of 0.85 THz. The static state and large signal characteristics of the devices are numerically simulated. The values of peak electric field strength, break-down voltage, avalanche voltage, the maximum generation rates of avalanche and tunneling, admittance-frequency relation, output power, conversion efficiency, quality factor of the proposed hetero-structural IMPATT and MITATT diodes are calculated, respectively. Via comparing the obtained results of (n)AlN/(p)GaN and (n)GaN/(p)AlN IMPATT diodes to those of the MITATT counterparts, there exists little performance difference between IMPATT and MITATT devices while implies significant difference between the (n)AlN/(p)GaN and (n)GaN/(p)AlN diodes.
Research of 3.3kV, 60A H-Bridge High-Voltage SiC Diode Modules
Authors: Hao Feng Bin , Jin Xiao Xing , Liu Ao , Li Shi Yan , Bai Song , Chen Gang
Published: November 2020

The simulation, fabrication and measurement of the high-voltage H-bridge SiC diode module is reported. The SiC module is consisted with 8 self-designed 3.3 kV30 A SiC Schottky diodes (SBDs), in which each bridge arm is connected by double SBD chips to achieve 60A current. Q3D is used to establish simulation model and make network division of the module. Two parasitic parameters, parasitic inductor and circuit resistance, are extracted from the circuits, which are about 37.5 nH and 1.9 mΩ, respectively. By establishing the geometric model and finite element model, finite element analysis software ANSYS is used to calculate steady-state thermal conduction, and the temperature gradient distribution of the formed chips. The results show that the maximum junction temperature of the chip is about 100°C, and the distribution of the temperature field is reasonable. As the lateral conduction of heat increases the effective heat dissipation area, there is no obvious concentration of heat. Under the condition of the test at room temperature and static, the module voltage drop is about 2.1 V, the leakage current is less than 5 uA, and the breakdown voltage is more than 3700 V, respectively. The fabricated 3300 V devices exhibit large safety margin. The insulation voltage exceeds 7000V, thus ensure the safety of the system. The thermal resistance of the chip is about 0.21 K/W, which is basically consistent with the simulation results.
Epitaxial Growth of “Strain-Free” Indium Oxide Films on (111) Yttria-Stabilized Zirconia by Metal-Organic Chemical Vapor Deposition
Authors: Zhuo Yi , Chen Zi Min , Zhang Sheng Dong
Published: November 2020

In this work, In2O3 thin films were grown on (111) yttria-stabilized zirconia (YSZ) by metal-organic chemical vapor deposition (MOCVD) at different temperature. It is found that samples grown at low temperature showed lower residual stress but higher mosaicity while high growth temperatures could also cause deterioration in crystal quality due to increasing lattice mismatch. To obtain high quality In2O3 film with low residual strain, a 30-nm thick layer grown at 530 °C was introduced as buffer layer, considering both stress relaxation and crystalline mosaicity. By using two-step growth method, a 400 nm-thick, high quality, near-strain-free In2O3 thin film with the full width at half maximum (FWHM) values of (222) diffraction peaks being as narrow as 648 arcsec was successfully obtained.
Study on the Synthesis of SiC Powder Material by Using Induction Heating System
Authors: Jiao Fang , Wu Zhou Li , Cui Dian Peng , Yang Mu Long , Dong Bo Yu
Published: November 2020

By using a NAURA Advanced Physical Vapor Transport (PVT) System, the character ofthe synthesized SiC powder were studied. Mainly from the aspects of purity and particle size, and relevant experiments were designed to understand the influence of the powder source on the synthesized SiC powder. The results showed that the selection of Si powder source with appropriate particle size was conducive to increase the proportion of large particle size of SiC powder. In addition, the purification of material source in the early stage of the process was beneficial to improve the purity of SiC powder. The results showed successful preparation of optimized SiC powder and thus high-quality SiC wafers were made.
SiC Trenched Schottky Diode with Step-Shaped Junction Barrier for Superior Static Performance and Large Design Window
Authors: Wang Xi , Pu Hong Bin , Hu Ji Chao , Liu Bing
Published: November 2020

A novel silicon carbide (SiC) trenched schottky diode with step-shaped junction barrier is proposed for superior static performance and large design window. In the proposed diode, to improve tradeoff between specific on-resistance and surface peak electric field, the shape of the trenched-junction is modified to stair-step, without extra fabrication process. To investigate the performances of the SiC step-shaped trenched junction barrier schottky (SSTJBS) diode, numerical simulations are carried out through Silvaco TCAD. The results indicate that the proposed diode can accommodate highly doped drift region with no degradation of its reverse blocking characteristic. In comparison with the conventional SiC trenched junction barrier schottky (TJBS) diode, the proposed SiC SSTJBS diode shows a larger design window of drift region doping concentration from 7.9×1015cm-3 to 9.5×1015cm-3. In the design window, the specific on-resistance and surface peak electric field can be reduced by 12.9% and 11%, respectively.
Proceedings of the 30th National Conference of the Italian Group for the Study of Neuromorphology “Gruppo Italiano per lo Studio della Neuromorfologia” G.I.S.N. Torino, November 12-14, 2020
Authors: Giancarlo Panzica Conference Chair:
Published: November 2020

Proceedings of the 30th National Conference of the Italian Group for the Study of Neuromorphology “Gruppo Italiano per lo Studio della Neuromorfologia” G.I.S.N., November 12-14, 2020, University of Torino, Torino (Virtual Event) - Italy.
Population Aspects of Graceful Mojarra Eucinostomus gracilis (Perciformes: Gerreidae) in a Coastal Lagoon in the Tropical Eastern Pacific
Authors: Rabago-Quiroz Carlos , Padilla-Serrato Jesús , López-Martínez Juana , García-Borbón Juan , Magaña Joaquin D.
Published: November 2020

Graceful mojarra (Eucinostomus gracilis) is an important component of the ichthyic fauna of lagoon systems but knowledge of its population aspects is scarce. Monthly samples in the Magdalena-Almejas Lagoon system (March-August, 2014-2017) were obtained with a trawling net. Abundance was estimated using the swept area method and its spatial variation; and the maturity size was determined using the logistic method. The sex ratio for mature and immature populations, and their length-weight relationship were estimated; FISAT was used to estimate the growth and recruitment parameters. Abundance ranged from 0.6 to 203 ind-Ha-1 with changes for each lagoon system areas and among years. Size at maturity (L50) was 132 mm in total length (TL) for the population, 129 mm TL females, and 135 mm TL males. Considering the population of the total organisms, L50 indicated that 18% were adults and 82% were juveniles. Juvenile dominance indicated that this lagoon system is used for grow-out. The smaller ratio of adult organisms does not allow asserting assertion that the priority of the area is for reproduction. E. gracilis showed moderate growth (K = 0.56 year-1) with longevity of 5.4 years and asymptotic length of L∞ = 195 mm.
Ova Fatty Acids Composition and Spawning Performances of Silver Carp, Hypophthalmichthys molitrix (Morocco)
Authors: Majdoubi Fatima-Zahra , Benhima Redouane , Ouizgane Anouar , Farid Sana , Droussi Mohammed , Guerriero Giulia , Hasnaoui Mustapha
Published: November 2020

The present study is performed in order to determine the relationship between fatty acid (FA) profile of silver carp (Hypophthalmichthys molitrix) eggs and fertilization success, embryos viability and larval production. Mature unfertilized ova were collected during the reproductive season from 23 mature and healthy females, reared in Deroua fish farm (Morocco). Total lipids were extracted from ova sample and subjected to trans-esterification then the resulting fatty acids methyl esters were analyzed by gas chromatography tandem mass spectrometry (GC/MS/MS). The results showed that silver carp ova are dominated on total FA by docosahexaenoic acid (DHA) (21.21%) followed by oleic acid (21.07%), palmitic acid (17.71%) and eicosapentaenoic acid (EPA) (10.25%). During the breeding season, polyunsaturateds (PUFAs), monounsaturateds (MUFAs) and saturated fatty acids (SFA) didn’t show any significant difference. Moreover, within the PUFAs, the n-3 series were more abundant than the n-6 series, the total mean was 31.57 ± 1.01% and 5.33 ± 0.32%, respectively. No correlation was between fatty acids and the fertilization success. Maternal weight has effect on the levels of oleic acid (C18:1), arachidonic acid (C20:4) and docosahexaenoic acid (C22:6) in the egg whereas levels of palmetoleic acid (C16:1), eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6) are related to female age.
Квантование семейства фазовых пространств
Authors: Wu Siye
Published: November 2020

Показано, что при квантовании фазовых пространств с переменными симплектическими структурами расслоение квантовых гильбертовых пространств над пространством параметров обладает естественной унитарной связностью. Дальнейшее исследование сосредоточено на симплектических векторных пространствах и их фермионных аналогах. После анализа того, каким образом квантовое гильбертово пространство зависит от физических параметров, таких как гамильтониан, и нефизических параметров, таких как выбор поляризации, изучены связности, кривизны и фазы расслоения гильбертовых пространств в том случае, когда меняется сама структура фазового пространства. Эти результаты применяются к семейству симплектических структур на гиперкэлеровом векторном пространстве, параметризованному двумерной сферой, и к его фермионному аналогу. В заключение рассмотрены возможные обобщения.
Емкости на компактной римановой поверхности
Authors: Chirka Evgenii Mikhailovich
Published: November 2020

Исследуются свойства емкости конденсаторов и емкостей компактов на компактной римановой поверхности, обобщающие свойства соответствующих объектов в комплексной плоскости. Определяются дискретные аналоги емкостей, и доказывается их сходимость к соответствующим емкостям компактов и конденсаторов.
Effects of skin and hide defects on quality grades and physical characteristics of crust leather
Authors: Tsigab Tewelde , Bsrat Abrha , Alemayohu Redae , Arefe Mengstu Ashebre , Kumar Niraj , Hadush Birhanu
Published: November 2020

Leather is one of the important export commodities in Ethiopia. However, itsquality and physical characteristics are affected by diseases, handling  and storage problems. A cross-sectional study was conducted to identify major hide and skin defects and assess their effect on quality grades and physical characteristics of crust leather. A total of 6530 hides and skins were inspected at Sheba Tannery and Leather Industry Private Limited Company (PLC) through standard operative procedures. For tests on physical characteristics of crust leather, top 6 defects of skin and hide were identified thereby each 5-crust leather per defect were evaluated by standard experiments for determining testing tensile strength, tear strength and percentage elongation at break. The overall hide and skin rejection was 32.7%. The rejection in wet blue hide (23.5%) was higher than for wet blue salted and dry goatskins (5.1%) and pickled sheepskins (4.1%). Scratch (20.5%), Wound (14.6%) and Cockle (12.7%), were the most common pre-slaughter skin and hide defects found in wet blue hide, goatskin and pickled sheepskin, respectively. Knife cut with proportion of 21.1%, 17.5% and 4.5% respectively in wet blue hide, goatskin and pickled sheepskin was the major slaughter defect. Putrefaction was of the most common post-slaughter defect in wet blue hide (5.3 %), pickled sheepskin (1.6%) and goatskin (2.7%). Among the identified major defects, statistically significant reduction (p<0.05) were noted in tensile strength, tear strength and percent elongation of the crust leather. Major skin and hide defects lead to considerable economical losses through reducing quality and physical performance characteristics of crust leather. Hence, innovative leather grade  correction technologies are timely important.

Keywords: Defects; hide; physical characteristics; quality; skin
Prevalence, organ distribution and antimicrobial susceptibility profile of Salmonella isolated from chickens purchased from markets in selected districts of West Shoa, Ethiopia
Authors: Sarba Edilu Jorga , Kudama Kebene , Dandecha Morka , Megersa Lencho , Borena Bizunesh Mideksa , Gebremdhin Endrias Zewdu
Published: November 2020

Salmonella is one of the major causes of heavy losses in chicken and foodborne diseases worldwide. The current study was conducted from  November 2015 to May 2016 to estimate the prevalence of Salmonella and determine the antimicrobial susceptibility of isolates in chickens. Chickens (n=205) were purchased from local markets of five selected districts of West Shoa Zone, Central Ethiopia. Following clinical examination, chicken were euthanized and 2-3 ml of blood sample was collected immediately. Then after postmortem examination, samples were collected from the liver, kidney, ovary, and spleen. The slide agglutination test was used to assess the seroprevalence of Salmonella antibodies. Isolation of Salmonella was performed according to the ISO-6579 procedure. The isolates were subjected to antimicrobial susceptibility testing (using 13 antimicrobial drugs) following the Kirby-Bauer disc diffusion method. The seroprevalence of Salmonella antibodies was 63.5% (95% CI: 55.9-70.5). The isolation rate of Salmonella was 19.0% (95% CI: 13.9-20.1) at the chicken level and 7.3% (95% CI: 5.5-9.4) at the organ level. The detection rate was 11.2%, 7.0%, 6.1%, and 4.4% for spleen, liver, ovary, and kidney, respectively. The majority of the Salmonella isolates were susceptible to norfloxacin (97.4%) and chloramphenicol (92.3%). All the 39 isolates were resistant to amoxicillin, tetracycline, and nitrofurantoin. Three multidrug resistance patterns to six antimicrobial classes were observed. Four isolates were resistant to five antimicrobial classes. Therefore, regular  surveillance of Salmonella and its antimicrobial resistance is needed for a better understanding of the epidemiological dynamics. Awareness creation for chicken farmers about improving farming practices and the risks of antimicrobial resistance warrants special attention.

Keywords: Antimicrobial susceptibility; Chicken; Prevalence; Salmonella; Ethiopia
Immunogenicity and protective efficacy of irradiated Salmonella Gallinarum against homologous challenge infection in Bovans brown chickens
Authors: Lulie Solomon , Alemayehu Haile , Nuru Anwar , Abayneh Takele , Eguale Tadesse
Published: November 2020

Fowl typhoid is a systemic poultry disease caused by Salmonella Gallinarum (SG). It is responsible for significant economic loss, due to its severe  morbidity and mortality. An irradiated vaccine is one of the possible alternatives to prevent and control fowl typhoid. This study aimed to evaluate the safety, immunogenicity, and protective efficacy of irradiated SG using a randomized control trial in chicken. A field strain of SG was exposed to different doses of gamma irradiation to determine its effect on the viability of SG. Safety and immunogenicity were assessed by administering irradiated SG orally to 3 groups (5 each) of 5 weeks old Bovans brown chickens at 2400, 2500, and 2600 gray (Gy). The protective efficacy of 108colony forming units (CFU) of SG irradiated at 2400 Gy administered orally and subcutaneously was then evaluated using homologous challenge infection and compared with SG 9R commercial vaccine using 40, 5-week old Bovans brown chickens where the chickens were randomly assigned to 4 groups. Chickens in Group 1were exposed to 108 CFU of irradiated SG orally; Group 2 to the same dose subcutaneously; Group 3 to SG 9R strain commercial vaccine subcutaneously, Group 4 to phosphate-buffered saline (PBS) orally. Data related to survival, antibody response, and pathological lesions were recorded. Mann-Whitney U-test, Kruskal-Wallis test, and Fisher’s exact tests were used to examine for statistical  significance. Irradiation at 2600 Gy caused complete inactivation of SG whereas SG exposed to 2400 Gy showed better immunogenicity and was safe for chickens. Antibody response in a group of chickens vaccinated with irradiated SG administered subcutaneously (SC) was significantly higher than  those vaccinated with the SG 9R vaccine on day 7 (p=0.003) and day 14 (p=0.002) post-immunization. Comparative evaluation of the protective efficacy based on the mortality rate of chickens after challenge showed that 2400 Gy irradiated SG vaccine administered SC and SG 9R vaccine-induced equal protection of 50% while the irradiated vaccine administered orally protected only 10% of chickens against homologous challenge infection. SG was not isolated from the liver, spleen, and feces of chickens that survived challenge infection until the end of the experiment. Irradiated SG administered SC is shown to be a promising vaccine against fowl typhoid. Further studies using a large sample size involving tuning of irradiation dose to improve immunogenicity and use of booster vaccination are recommended.

Keywords: Chicken; Fowl typhoid; Gamma irradiation; Salmonella Gallinarum; Vaccine