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Abstract

This paper presents the findings of a study of gas emissivity and the volumetric gas flow rate from a patented modified cellulose mix used

in production of disposable sand casting moulds. The modified cellulose mix with such additives as expanded perlite, expanded

vermiculite and microspheres was used as the study material. The results for gas emissivity and the gas flow rate for the modified cellulose

mix were compared with the gas emissivity of the commercial material used in gating systems in disposable sand casting moulds. The

results have shown that the modified cellulose mix is characterized by a lower gas emissivity by as much as 50% and lower gas flow rate

per unit mass during the process of thermal degradation at the temperature of 900°C, compared to the commercial mix. It was also noted

that the amount of microspheres considerably affected the amount of gas produced.

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Authors and Affiliations

J. Sawicki
Z. Zawieja
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Abstract

Nowadays, there are growing demands on the accuracy of production. Most of this is reflected in precise manufacturing, such as the investment casting process. Foundries are looking for causes of defects in some cases for a very long time, and it may happen that the source of defects is completely different from what was originally assumed. During the casting process there exist potential causes of defects as oxygen inclusions. This paper represents a summary of the beginnings of a wider research that will address the problems of gating systems in investment casting technology. In general, the influence of the melt flow is underestimated and the aim of the whole scientific research is to demonstrate the significant influence of laminar or turbulent flow on the resulting casting quality. Specifically, the paper deals with the analysis of the most frequent types of defects found in castings made of expensive types of materials casted in an open atmosphere and demonstration of connection with the design of gating systems in the future.
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Authors and Affiliations

O. Vrátný
A. Herman
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Abstract

Foundry technologists use their own style of gating system designing. Most of their patterns are caused by experience. The designs differ from plant to plant and give better or worse results. This shows that the theory of gating systems is not brought into general use sufficiently and therefore not applied in practise very often. Hence, this paper describes the theory and practical development of one part of gating systems - sprue base for automated horizontal moulding lines used for iron castings. Different geometries of sprue bases with gating system and casting were drawn in Solid Edge ST9. The metal flow through the gating systems was then simulated with use of MAGMA Express 5.3.1.0, and the results were achieved. The quality of flow was considered in a few categories: splashes, air entrapment, vortex generation and air contact. The economical aspect (weight of runner) was also taken under consideration. After quantitative evaluation, the best shape was chosen and optimised in other simulations with special attention on its impact on filling velocity and mould erosion. This design (a sprue base with notch placed in drag and cope) is recommended to be used in mass production iron foundries to reduce oxide creation in liquid metal and especially to still metal stream to improve filtration.

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Authors and Affiliations

J. Dorula
B. Siodmok
J. Jezierski
R. Romelczyk
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Abstract

In order to study the effects of various gating systems on the casting of a complex aluminum alloyed multi-way valve body, both software simulation analysis and optimization were carried out. Following, the aluminum alloyed multi-way valve body was cast to check the pouring of the aluminum alloy valve body. The computer simulation results demonstrated that compared to the single side casting mode, the casting method of both sides of the gating system would reduce the filling of the external gas, while the air contact time would be lower. Adversely, due to the pouring on both sides, the melt cannot reach at the same time, leading to the liquid metal speed into the cavity to differ, which affected the liquid metal filling stability. The riser unreasonable setting led to the solidification time extension, resulting in a high amount of casting defects during solidification. Also, both gating systems led the entire casting inconsequential solidification. To overcome the latter problems, a straight gate was set at the middle pouring and the horizontal gate diversion occurred on both sides of pouring, which could provide better casting results for the aluminum alloyed multi-valve body.
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Authors and Affiliations

Rong Li
Lunjun Chenb
Ming Su
Qi Zeng
Yong Liu
Heng Wang
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Abstract

Throughout the casting process, mold filling plays a very significant role in the casting quality control. It is important to study the effect of gating system design on ingate velocity of the metal which affects the mechanical properties of casting. The effect of varying the design of four gating system elements namely pouring cup, sprue height, runner and ingate design on the multiple responses like tensile strength and percentage elongation is studied using a Taguchi’s L9 OA. The Taguchi technique was coupled with a Grey Relational Analysis (GRA) to obtain a Grey Relational Grade (GRG) for evaluating multiple responses. ANOVA has been applied to identify the significance of different parameters and it was found that the pouring cup design and the runner cross-section along its length collectively contributed above 76% of the total GRG value. Finally, the confirmation tests were performed to validate the predicted optimized results and it established an improvement of 9.90% from the initial design.

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Authors and Affiliations

P.D. Ingle
B.E. Narkhede
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Abstract

Submitted work deals with the analysis of reoxidation processes for aluminium alloys. Due to the aluminium high affinity to the oxygen, the oxidation and consequently reoxidation will occur. Paper focuses on the gating system design in order to suppress and minimize reoxidation processes. Design of the gating system is considered as one of the most important aspect, which can reduce the presence of reoxidation products - bifilms. The main reason for the reoxidation occurrence is turbulence during filling of the mold. By correctly designing the individual parts of gating system, it is possible to minimize turbulence and to ensure a smooth process of the mold filling. The aim of the work is an innovative approach in the construction of gating system by using unconventional elements, such as a naturally pressurized system or vortex elements. The aim is also to clarify the phenomenon during the gating system filling by visualization with the aid of ProCAST numerical simulation software. ProCAST can calculate different indicators which allow to better quantify the filling pattern.

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Authors and Affiliations

A. Remišová
M. Brůna
ORCID: ORCID
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Abstract

In this paper the new synthesis method for reversible networks is proposed. The method is suitable to generate optimal circuits. The examples will be shown for three variables reversible functions but the method is scalable to larger number of variables. The algorithm could be easily implemented with high speed execution and without big consuming storage software. Section 1 contains general concepts about the reversible functions. In Section 2 there are presented various descriptions of reversible functions. One of them is the description using partitions. In Section 3 there are introduced the cascade of the reversible gates as the target of the synthesis algorithm. In order to achieve this target the definitions of the rest and remain functions will be helpful. Section 4 contains the proposed algorithm. There is introduced a classification of minterms distribution for a given function. To select the successive gates in the cascade the condition of the improvement the minterms distribution must be fulfilled. Section 4 describes the algorithm how to improve the minterms distributions in order to find the optimal cascade. Section 5 shows the one example of this algorithm.

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Authors and Affiliations

Andrzej Skorupski
Krzysztof Gracki
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Abstract

The article presents the author’s considerations on the significance of the investment package diversifying natural gas supplies as part of the Northern Gate in ensuring Poland’s energy security. Data found in literature concerning the possibilities of importing the raw material by sea (terminals, gas pipelines) includes investments at various stages of concept development and construction. However, these documents lack cohesive information about a full investment package being implemented. The author has thus attempted at creating variants concerning the diversification capacities of the Republic of Poland in reference to several key offshore and onshore projects. A problem has therefore been formulated: To what extend will the Northern Gate investment package increase Poland’s energy security as a result of increased supply of natural gas from the sea? To answer this questions, researchers were forced to verify their working hypothesis which assumed that Northern Gate investments including a comprehensive package of projects had the potential of significantly improving the level of energy security in Poland by extending the possibility of importing natural gas. To solve the problem and verify the hypothesis, the researchers applied systemic analysis, deduction and variant analysis, which were used to estimate the possible import capacities of the raw material by sea. As a result of the works, the researchers created four variants including various investment projects assuming the import of 7.75 m3 to 30,95 B m3 of natural gas a year by sea. The variant which was adopted as the most probable indicates the possibility of importing 17.75 through 22.75 B m3 of gas a year, which is 111% of the average annual demand in Poland.

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Authors and Affiliations

Andrzej Rafał Miętkiewicz
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Abstract

In this work we report on fabrication of quantum wires and quantum point contacts from the modulation doped CdMgTe/Cd(Mn)Te structures, with the application of a high-resolution electron-beam lithography. We emphasize on methods which were not yet utilized for these substrate materials. In particular, we describe the so-called shallow-etching approach, which allows for the fabrication of quantum constrictions of a physical width down to 100 nm, which are characterized by the smoother confining potential as compared to the deep-etched devices. For that purpose, a single-line exposure mode of electron-beam lithography has been used. We demonstrate also, how to combine the etching of separating grooves with the thermal evaporation of metal side-gates into a single post-processing stage of a quantum point contact fabrication.

This article is an expanded version of the scientific reports presented at the International Conference on Semiconductor Nanostructures for Optoelectronics and Biosensors 2016 ICSeNOB2016, May 22–25, 2016, Rzeszow, Poland.

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Authors and Affiliations

Joanna Wróbel
E. Bobko
Dariusz Płoch
ORCID: ORCID
M. Wiater
T. Wojtowicz
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Abstract

Submitted work deals with the possibilities of reducing reoxidation by improved gating system design. The result of the reoxidation is the of furled oxide layers – bifilms. During experimental works, non-pressurized and naturally pressurized gating systems designs were introduced and evaluated. Mechanical properties, fracture area, hot tearing index, bifilm index and EDX analysis were used during evaluation. Paper aim is also to clarify the reoxidation phenomenon by visualization with the aid of ProCAST numerical simulation software. Achieved results clearly confirmed the positive effect of the naturally pressurized gating system, main emphasis needs to focus on finding the proper way to reduce the melt velocity. By using vortex element extension at the end of the runner was achieved positive results in term of reoxidation suppression.
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Authors and Affiliations

M. Brůna
1
ORCID: ORCID
M. Galčík
1
A. Sládek
1
D. Martinec
1

  1. University of Žilina, Faculty of Mechanical Engineering, Department of Technological Engineering, Univerzitná 8215/1, 010 26 Žilina, Slovakia
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Abstract

The major part of the paper is describing practice of using oral history method in the “Grodzka Gate – NN Theater” Center in Lublin. This cultural center started collecting testimonies in 1995 and formally created the Oral History Program in 1998. Educational and artistic exemplars include most of activities there: using oral history as a background in exhibitions, artistic celebrations and long-term programs, commemorations (about Righteous Among the Nations, Holocaust Survivors etc.).
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Authors and Affiliations

Andrzej Zinczuk
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Abstract

In this research work, a Cylindrical Surrounding Double-Gate (CSDG) MOSFET design in a stacked-Dual Metal Gate (DMG) architecture has been proposed to incorporate the ability of gate metal variation in channel field formation. Further, the internal gate's threshold voltage (VTH1) could be reduced compared to the external gate (VTH2) by arranging the gate metal work-function in Double Gate devices. Therefore, a device design of CSDG MOSFET has been realized to instigate the effect of Dual Metal Gate (DMG) stack architecture in the CSDG device. The comparison of device simulation shown optimized electric field and surface potential profile. The gradual decrease of metal work function towards the drain also improves the Drain Induced Barrier Lowering (DIBL) and subthreshold characteristics. The physics-based analysis of gate stack CSDG MOSFET that operates in saturation involving the analogy of cylindrical dual metal gates has been considered to evaluate the performance improvements. The insights obtained from the results using the gate-stack dual metal structure of CSDG are quite promising, which can serve as a guide to further reduce the threshold voltage roll-off, suppress the Hot Carrier Effects (HCEs) and Short Channel Effects (SCEs).
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Authors and Affiliations

Abha Dargar
1
Viranjay M. Srivastava
1

  1. Department of Electronic Engineering, Howard College, University of KwaZulu-Natal, Durban, 4041, South Africa
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Abstract

Mineral-resource mining is a pillar of many state economies and, in many cases, it determines the welfare of the society. The mining of mineral resources provides the market with the raw materials that are traded and drives the economic and social development of countries, although it can also be a source of tensions and crises (e.g. the “curse of wealth”, “Dutch disease”). The trade of raw materials is conducted by exchanges, bilateral deals and other forms of transactions, and is regulated by trade regulations and contract agreements, and in most cases, constitutes a source of income for exporters. In this paper, the use of game-theory modelling for creating the selling price of mineral products on the basis of Polish export quotas for refined copper raw materials is proposed. Using a characteristic function created on the basis of reported export values, possible cooperation arrangements are defined and solutions are calculated for an n-person game of hypothetical coalitions of the major (in terms of volume) recipients of refined Polish copper, i.e. Germany, Italy and France. Alternative markets and possible supplies of cheaper raw material are excluded from the analyses, while the price spread between the rates paid by the buyers is taken into consideration. Among the many possibilities, the game core, the Shapley imputation and the Gately point are arbitrarily adopted as permissible solutions to the defined system. The obtained results are used for a speculative analysis relating to the possibility of renegotiating prices between the producer and recipients of the raw material. Marginal contributions resulting from Shapley’s solution are taken into account as is the power of individual trading-participant coalitions. The paper demonstrates that the recognition and adoption of solutions based on the n-personnel game model as impartial would require the redefinition of contracts and the rates paid for the raw material.
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Authors and Affiliations

Mariusz Krzak
1

  1. AGH University of Science and Technology, Kraków, Poland
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Abstract

This paper deals with the implementation of a DC and AC double-gate MOSFET compact model in the Verilog- AMS language for the transient simulation and the configuration of ultra low-power analog circuits. The Verilog-AMS description of the proposed model is inserted in SMASH circuit simulator for the transient simulation and the configuration of the Colpitts oscillator, the common-source amplifier, and the inverter. The proposed model has the advantages of being simple and compact. It was validated using TCAD simulation results of the same transistor realized with Silvaco Software.
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Bibliography

[1] N. Arora, “MOSFET Modeling for VLSl Circuit Simulation: Theory and Practice,” World Scientific, 1993.
[2] International Technology Roadmap for Semiconductors. Available: http://www.itrs2.net, 2017.
[3] O. Samy, H. Abdelhamid, Y. Ismail, A. Zekry, “A 2D compact model for lightly doped DGMOSFETs (P-DGFETs) including negative bias temperature instability (NBTI) and short channel effects (SCEs),” Microelectronics reliability, 2016, 67, 82-88.
[4] J-P. Colinge, “FinFETs and Other Multi-Gate Transistors,” Springer, 2008.
[5] A. Amara, “Planar Double-Gate Transistor, From Technology to Circuit,” Springer, 2009.
[6] D. Stefanović, M. Kayal, M, “Structured Analog CMOS Design,” Springer, 2008.
[7] A. Mangla, M.-A. Chalkiadaki, F. Fadhuile, T. Taris, Y. Deval, C. C. Enz, “Design methodology for ultra low-power analog circuits using next generation BSIM6 MOSFET compact model,” Microelectronics journal, 2013, 44, 570-575.
[8] A.B. Bhattacharyya, “Compact MOSFET models for VLSI design,” Wiley, 2009.
[9] B. Smaani, S. Latreche, B. Iñiguez, „Compact drain-current model for undoped cylindrical surrounding-gate MOSFETs including short channel effects,” J. Appl. Phys., 2013, 114.
[10] J-M. Sallese, F. Krummenacher, F. Prégaldiny, „A design oriented charge-based current model for symmetric DG MOSFET and its correlation with the EKV formalism,” Solid-State Electronics, 2012, 49, 485-489.
[11] O. Moldovan, F. Lime, S. Barraud, B. Smaani, „Experimentally verified drain-current model for variable barrier transistor,” IET Electronics Letters, 2015, 51, 17, 364–366.
[12] J. Alvarado, B. Iñiguez, M. Estrada, “Implementation of the symmetric doped double-gate MOSFET model in Verilog-A for circuit simulation,” Int. J. Numer. Model, 2010, 23, 88–106.
[13] O. Cobianu, M. Soffke, A. Glesner, “Verilog-A model of an undoped symmetric dual-gate MOSFET,” Int. Adv. Radio Sci, 2006, 4, 303–306.
[14] M. Cheralathan, E. Contreras, J. Alvarado, “Implementation of nanoscale double-gate CMOS circuits using compact advanced transport models,” Microelectronics Journal, 2013, 44, 80–85. [15] Verilog-AMS User Manual, Accellera 2006.
[16] B. Smaani, M. Bella, S. Latreche, “Compact Modeling of Lightly Doped Nanoscale DG MOSFET Transistor,” Applied Mechanics and Materials, 2014, 492, 06–10.
[17] O. Samy, H. Abdelhamid , Y. Ismail, A. Zekry, “A 2D compact model for lightly doped DG MOSFETs (P-DGFETs) including negative bias temperature instability (NBTI) and short channel effects (SCEs),” Microelectronics Reliability, 2016, 67, 82-88.
[18] Y. Taur, X. Liang, “A continuous, analytic drain-current model for DG MOSFETs,” IEEE Electron device Letters, 2004, 25, 2, 107–109.
[19] J-M. Sallese, A. S. Porret, “A novel approach to charge-based non-quasi-static model of the MOS transistor valid in all modes of operation,” Solid-State Electronics, 2000, 44, 887-894.
[20] H. Børli, S. Kolberg, “Capacitance modeling of short-channel double-gate MOSFETs,” Solid-State Electronics, 2008, 52, 1486–1490.
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[22] M. Bella, S. Latreche, C. Gontrand, “Nanoscale DGMOSFET: DC modification and Analysis of Noise in RF Oscillator,” Journal of Applied Sciences,2015, 5, 800–807.
[23] R. Blaise, W. Tekam, J. Kengne, G. D. Kenmoe, “High frequency Colpitts’ oscillator: A simple configuration for chaos generation,” Chaos, Solitons & Fractals, 2019, 126, 351–360.
[24] A.Rana1, P. Gaikwad, “Colpitts oscillator: design and performance optimization,” Int. Journal of Applied Sciences and Engineering Research, 2014, 3, 913–919.
[25] SMASH User Manual Version 5.18 Release, 2012.
[26] Device simulator ATLAS, Silvaco International, 2007.
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Authors and Affiliations

Billel Smaani
1
Yacin Meraihi
2
Fares Nafa
2
Mohamed Salah Benlatreche
3
Hamza Akroum
4
Saida Latreche
5

  1. Ingénierie des Systémes Electriques Department, Faculty of Technology, Boumerdes University, Algeria
  2. Laboratoire d'Ingénierie et Systèmes de Télécommunications, Faculté de Technologie, Boumerdes, Algeria
  3. Centre Universitaire Abdel Hafid Boussouf Mila, Algeria
  4. Laboratoire d’Automatique Appliquée, Université M’Hamed Bougara de Boumerdes, Algeria
  5. Laboratoire Hyperfréquences et Semiconducteurs, Electronique Department, Constantine 1 University, Algeria
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Abstract

One of the main reason for decreased internal homogeneity of aluminium alloy castings is reoxidation. The resulting products of reoxidation are doubled oxides, so called "bifilms". Submitted paper deals with optimization of gating system design in order to reduce reoxidation processes taking place in mold cavity. Experimental work compares and evaluates three gating systems designs based on non-pressurized and naturally pressurized principles. Unconventional spin trap extension of runner was used in third design. Among the evaluated aspects were: mechanical properties, hot tearing index, visual inspection of average porosity amount, numerical simulation of velocity, turbulence and oxide amount. Paper aim is also to clarify the reoxidation phenomenon by visualization with the aid of ProCAST numerical simulation software. Results of mechanical properties and hot tear index clearly confirmed the positive effect of the naturally pressurized gating system with applied element for velocity reduction.
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Bibliography

[1] Svoboda, J.M., Monroe, R.W., Bates, C.E. & Griffin, J. (1987). TAFS. 95, 187-202.
[2] Campbell, J. (2006). Entrainment defects. Materials Science and Technology. 22(2), 127-145. ISSN 0267-0836. https://doi.org/10.1179/174328406X74248.
[3] Campbell, J. (1993). Invisible Macrodefects in castings. Journal de Physique Archives. 03(C7), 861-872. https://doi.org/10.1051/jp4:19937135.
[4] Dojka, R. Jezierski, J. & Campbell, J. (2018) Optimized gating system for steel castings. Journal of Materials Engineering and Performance. 10. DOI: 10.1007/s11665-018-3497-1.
[5] Sladek, A., Patek, M. & Mician, M. (2017). Behavior of steel branch connections during fatigue loading‎. Archives of Metallurgy and Materials. 62 (3), 1597-1601‏.
[6] Brůna, M., Bolibruchová, D. & Pastirčák, R. (2017). Archives of Foundry Engineering. 17, 23-26. https://doi.org/10.1515/afe-2017-0084.
[7] Lin, S., Aliravci, C. & Pekguleryuz, N.I.O. (2007). Hot-tear susceptibility of aluminum wrought alloys and the effect of grain refining. Materials Science and Engineering. A Sci. 38A, 1056-1068. https://doi.org/10.1007/s11661-007-9132-7.
[8] Campbell, J. (2006). An overview of the effects of bifilms on the structure and properties of cast alloys. Metallurgical and Materials Transaction B. 37, 857-863. https://doi.org/ 10.1007/BF0273500.

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Authors and Affiliations

M. Bruna
1
ORCID: ORCID
M. Galčík
1

  1. Department of Technological Engineering, University of Zilina, Univerzitna 1, 010 26 Zilina, Slovakia
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Abstract

In order to achieve higher frequency measurement accuracy, this paper proposed a characteristic pulse detection method of fuzzy area based on the quantized phase processing method of different frequency groups. First, the fuzzy area of the group phase coincidence points continuously moved on the time axis after passing through delay elements. The moving distance, that is, the number of the delay elements was determined by the main clock cycle of the D flip-flop. After that, three groups of phase coincidence detection fuzzy areas in different positions were sent to the digital logic module to extract the edge pulses of the phase coincidence detection fuzzy area. The pulse width is determined by the difference between the clock cycles of the delay elements. The clock cycles of different delay units were adjusted to obtain nanosecond or even picosecond circuit detection resolution. Finally, the pulses generated at the edge of the phase coincidence fuzzy area are taken as the switching signal of the frequency signal counter, so the stability of the gate signal and the accuracy of the gate time measurement are improved. The experimental results show that frequency stability can reach the order of E-13/s. In addition, compared with the traditional measurement method, it is characterized by simple structure, low cost, low noises, and high measurement resolution.
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Authors and Affiliations

Xin Geng
1
Baoqiang Du
2

  1. School of Computer and Communication Engineering, Zhengzhou University of Light Industry, Zhengzhou 450000, China
  2. College of Information and Engineering, Hunan Normal University, Changsha 410081, China
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Abstract

This work evaluates the influence of gate drive circuitry to cascode GaN device’s switching waveforms. This is done by comparing three PCBs using three double-pulse-test (DPT) with different gate driving loop design. Among important parasitic elements, source-side inductance shows a significant impact to gate-source voltage waveform. A simulation model based on experimental measurement of the cascode GaNFET used in this work is modified by author. The simulation model is implemented in a synchronous buck converter topology and hereby to assess the impact of gate driving loop of cascode GaN device in both continuous conduction mode (CCM) and critical conduction mode (CRM). Apart from simulation, a synchronous buck converter prototype is presented for experimental evaluation, which shows a 99.15% efficiency at 5A under soft-switching operation (CRM) with a 59ns dead-time.
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Bibliography

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Authors and Affiliations

Q.Y. Tan
1
E.M.S. Narayanan
1

  1. Department of Electronic and Electrical Engineering, The University of Sheffield, S1 3JD, UK
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Abstract

Blood glucose level monitoring and control is of utmost importance to millions of people who have been diagnosed with diabetes or similar illnesses. One of the conventional tests for measuring how the human body breaks down glucose is IVGTT, the Intravenous Glucose Tolerance Test. The difficulty of computing the models of glucose-insulin interaction presents an issue when attempting to implement them in embedded hardware. The Metabolic P (MP), contrary to other models, does not require solving differential equations to compute, thus it could be an effective modelling approach for real-time applications. The present paper proves that MP system methodology-based IVGTT implementation in the Field Programmable Gate Arrays (FPGA) technology is reasonably precise and sufficiently flexible to be used effectively in multi-user scenarios. Presentation of the state-of-the-art focuses on glucose-insulin interaction models, glucose monitoring systems and MP system implementation techniques. Methods for MP system computations and techniques for their implementation on FPGA, together with the original unified MP system implementation technique, have been presented in this paper. The results of an elaborate investigation into the IVGTT MP systems, as well as their single and unified MP implementation techniques have also been considered. It is shown that the techniques developed are applicable to all known IVGTT MP systems, and can achieve RMSE not higher than 15% using a word length of at least 32 bits. The novel MP system combined quality metrics and its pictorial representation allow the analysis of various implementation characteristics. Compared to the unified pipelined IVGTT MP system implementation technique, the developed unified combinational technique ensures a 2‒3 times higher speed.

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Authors and Affiliations

D. Kulakovskis
T. Sledevič
A. Gedminas
D. Navakauskas
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Abstract

The article presents the results of experimental research aimed at recognizing the impact of the design of energy dissipation devices on the formation of bed local scouring below the sluice gate. The experiments were carried out on a model of a sluice gate built in a rectangular flume with a width of 0.58 m, with the outflow of the stream from under the slider to a horizontal bed 0.80 m long. Behind the dam gate valve three different constructions of energy dissipation devices were used: flat, horizontal slab, slab equipped with baffle blocks arranged in two rows and rip-rap. The experiments assumed forming a scour hole in 480 minutes downstream the sluice, where the bed was filled with sorted sand. The depths of the scour were measured in the longitudinal profile after 30, 60, 90, 120, 180, 240, 300, 360, 420 and 480 minutes. The deepest scour holes of the bed, both in terms of depth and length, occurred on the structure model with energy dissipation devices made as a flat, horizontal plate. At the same time, in this case, the hole was developing the most rapidly, and its shape and size posed the greatest threat to the stability of the structure. The use of baffle blocks arranged in two rows or a rip-rap behind the structure slide noticeably reduced the size of the scour and delayed the erosion of the bottom in time, as compared to the course of this process on a model with a flat, horizontal slab.

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Authors and Affiliations

Janusz Urbański
ORCID: ORCID
Marta Justyna Kiraga
Sławomir Bajkowski
ORCID: ORCID
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Abstract

The composite weir-gate structure is considered an important hydraulic structure. This is because of its widely used in civil engineering hydraulic works especially in an irrigation system to measure, control, divert and keep the required water level. This study focuses on the influence of barrier existence on the hydraulic parameters that described the hydraulic characteristics of composite weir-gate hydraulic structure. In this study, several experimental runs were conducted to determine the effect of barrier's location, spacing and number on the water level and depth at the downstream region of flume, discharge coefficient of composite hydraulic structure, and flow rate throughout the flume. Our experiments indicated that the turbulence intensity, inlet effect, and position, gap, and number of barriers have affected the hydraulic behavior of weir-gate structure. This appears clearly by obtaining different results of discharge coefficient and flow rate that cross the weir-gate structure comparing with same cases without barriers. Also this study gives some insights on the significance roles of fluid separation, eddies generation near the barrier, fluid resistance and overlap between overflow and underflow velocities and their effects on hydraulic factors that dominate the problem. These hydraulic factors must be considered in the design and construction of barrier/barriers in open channel to prevent any fluctuation or drop in discharge, water elevation and the required water depth at downstream region.

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Authors and Affiliations

Rafi M. Qasim
Ihsan A. Abdulhussein
Khalid Al-Asadi
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Abstract

This article analyses a hierarchical structure of academia within two academic social media networking sites, i.e. Academia.edu and ResearchGate. In this study, I investigate profiles (in these two services) of all academic staff members of Adam Mickiewicz University in Poznań (N = 2661). I use the concept of prestige to analyse whether the hierarchical structure of academia is being reproduced in analysed services. Since prestige is an unobservable construct, I use two indicators to measure it: the number of followers and the number of views. My findings show that the hierarchical structure differs between Academia.edu and Research- Gate. While the structure of ResearchGate is explicitly hierarchical in reference to degrees of the researchers (a higher degree is related to a higher value of the prestige indicators), the structure of Academia.edu resembles a reversed pyramid (a higher degree is related to a lower value of the prestige indicators). The article concludes with a discussion concerning possible causes of differences between services in terms of reproducing the hierarchical structure. Moreover, I provide potential implications of the results as well as the justification of the necessity of using the concept of prestige to determine hierarchical structure of academia.

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Kinga Ciereszko
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Abstract

Range-gated-imaging system, which can be used to eliminate backscatter in strong scattering environments, is based on two high speed technologies. It uses high power, ultra-short pulse laser as the light source. And it opens the optical gate of an ICCD camera with a micro-channel-plate image intensifier in a very short time while the laser pulses reflected by the object is coming back to the ICCD camera. Using this range-gated-imaging technology, the effect of scattered light can be reduced and a clear image is obtained.

In this paper, the test results of the range-gated-imaging system under dense aerosol environments, which simulates environments in the reactor containment building when the severe accident of the nuclear power plant occurred, are described. To evaluate the observation performance of the range-gated-imaging system under such dense fog environment, we made a test facility. Fog particles are sprayed into the test facility until fog concentration is reached to the postulated concentration level of the severe accident of the nuclear power plant. At such dense fog concentration conditions, we compared and evaluated the observation performances of the range-gated-imaging system and the CCD camera.

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Authors and Affiliations

J.W. Cho
Y.S. Choi
K.M. Jeong
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Abstract

The field programmable gate array (FPGA) is used to build an artificial neural network in hardware. Architecture for a digital system is devised to execute a feed-forward multilayer neural network. ANN and CNN are very commonly used architectures. Verilog is utilized to describe the designed architecture. For the computation of certain tasks, a neural network’s distributed architecture structure makes it potentially efficient. The same features make neural nets suitable for application in VLSI technology. For the hardware of a neural network, a single neuron must be effectively implemented (NN). Reprogrammable computer systems based on FPGAs are useful for hardware implementations of neural networks.
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Authors and Affiliations

B A Sujatha Kumari
1
Sudarshan Patil Kulkarni
1
C G Sinchana
1

  1. Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, Mysore, India
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Authors and Affiliations

Mahesh V. Sonth
1
G. Srikanth
1
Pankaj Agrawal
1
B. Premalatha
2

  1. Department of Electronics and Communication Engineering, CMR Technical Campus, Hyderabad-501401, Telangana, India
  2. Department of Electronics and Communication Engineering, CMR College of Engineering & Technology, Hyderabad-501401,Telangana, India

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