Volume 52, Issue 1-2, 2017

Issue 9-12, 2022

ELECTROTECHNICA & ELECTRONICA E+E

Vol. 57. No 9-12/2022
Monthly scientific and technical journal
Published by:
The Union of Electronics, Electrical Engineering and Telecommunications /CEEC/, BULGARIA

20220912-full

C O N T E N T S

Mihail Digalovski, Goran Rafajlovski, Krste Najdenkoski
Energy efficiency improvements in electric drives with centrifugal load 79

Jeremy Blades, Dr Karl O. Jones, Colin Robinson
Audio restoration of dubplates: cleaning and digital processing lacquer records from reggae/dancehall culture 87

Lachezar Lichev, Viktória Hránková, Michaela Masárová, Jakub Lubojacký, Petr Matoušek
Approach in measuring nasal cavity and PNS volume 97

Dr Karl O. Jones, Bethan S. Jones
How robust is the United Kingdom justice system against the advance of deepfake audio and video? 103

Energy efficiency improvements in electric drives with centrifugal load
Mihail Digalovski, Goran Rafajlovski, Krste Najdenkoski

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Electric drives with centrifugal torque characteristic are a typical low efficiency drives. These include fans, pumps, blowers etc. In these electric drives, there is great technical and economic potential for significant energy savings. Pumps are the most numerous working machines, therefore the electric drives with pump will be considered in this paper. First, as opportunity to increase energy efficiency will be presented the replacement of existing electric motors in these drives with highly efficient motors – HEM. Will be made an analysis how much is savings due to reduced losses in highly efficient electric motors. The next, will be given a brief introduction to pump systems and then will be presented the ways in which the operating point of the pump can be regulated. In addition, is presented a calculation for energy savings was made a comparison between conventional ways of regulating the operating point of the pump and regulation of the operating point through variable electric drive speed. It analyzes the electricity consumption of low, medium and high-power pumps driven by induction motors that have the ability to regulate the rotation speed through an inverter with U/f regulation.


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Digalovski M., Rafajlovski G., Najdenkoski K. Energy efficiency improvements in electric drives with centrifugal load. Electrotechnica & Electronica (Е+Е), Vol. 57 (9-12), 2022, pp.79-86, ISSN: 0861-4717 (Print), 2603-5421 (Online)

Audio restoration of dubplates: cleaning and digital processing lacquer records from reggae/dancehall culture
Jeremy Blades, Karl O. Jones, Colin Robinson

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This paper discusses the cleaning and digital restoration of lacquer records from the Reggae/Dancehall culture known as Dubplates. The paper evaluates the use of certain digital restoration tools used in the processing of the digital audio file. It also discusses the merits of using household goods in the cleaning of these records. The paper also evaluates the use and overuse of certain digital processing tools. This paper is intended to educate laypeople to save these artefacts from further deterioration, and to interest people who are familiar with Reggae culture as well as those who are interested in audio restoration.


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Blades J., Jones K.O., Robinson C. Audio restoration of dubplates: cleaning and digital processing lacquer records from reggae/dancehall culture. Electrotechnica & Electronica (Е+Е), Vol. 57 (9-12), 2022, pp.87-96, ISSN: 0861-4717 (Print), 2603-5421 (Online)

Approach in measuring nasal cavity and PNS volume
Lachezar Lichev, Viktória Hránková, Michaela Masárová, Jakub Lubojacký, Petr Matoušek

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With the method and approach developed within the Fotom module, the results obtained are comparable to other volumetric instruments (e.g. OssiriX). This software product is free, easily accessible and applicable in healthcare facilities around the world, unlike other systems that are expensive and often tied to a specific platform, such as the currently available Osirix software. Photogrammetry software can be widely used in otolaryngological practice. One possible use is to measure the nasal cavity and paranasal sinuses (PNS) volume. Knowledge of the development of PNS, anatomy and volume is crucial for the management of pathologies in this area. The importance of knowledge about the volume of the PNS and nasal cavity and their development lies in the great individual variability in the level of their pneumatization and the actual size of the skull. In addition, the establishment of PNS and nasal cavity volume as a standard part of preoperative radiological examination may contribute to the safety and efficacy of endoscopic sinus surgery and transnasal skull-based surgery.

 

С метода и подхода, разработен в рамките на модула Fotom, получените резултати са сравними с други обемни инструменти (напр. OssiriX). Този софтуерен продукт е безплатен, лесно достъпен и приложим в здравни заведения по света, за разлика от други системи, които са скъпи и често обвързани с конкретна платформа, като наличния в момента софтуер Osirix. Софтуерът за фотограметрия може да се използва широко в отоларингологичната практика. Една възможна употреба е за измерване на обема на носната кухина и параназалните синуси (PNS). Познаването на развитието на PNS, анатомията и обема е от решаващо значение за управлението на патологиите в тази област. Значението на познаването на обема на ПНС и носната кухина и тяхното развитие се крие в голямата индивидуална вариабилност в нивото на тяхната пневматизация и реалния размер на черепа. В допълнение, установяването на PNS и обема на носната кухина като стандартна част от предоперативното рентгенологично изследване може да допринесе за безопасността и ефикасността на ендоскопската хирургия на синусите и трансназалната хирургия на черепа.


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Lichev L., Hránková V., Masárová M., Lubojacký J., Matoušek P. Approach in measuring nasal cavity and PNS volume. Electrotechnica & Electronica (Е+Е), Vol. 57 (9-12), 2022, pp.97-102, ISSN: 0861-4717 (Print), 2603-5421 (Online)

How robust is the United Kingdom justice system against the advance of deepfake audio and video?
Karl O. Jones, Bethan S. Jones

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A recent development is the application of AI to either alter or create video and audio files – called Deepfakes. The paper examines the issues arising from deepfakes, to determine how robust the UK justice system is against deepfakes. The work analyses deepfake technology, with respect to an evaluation of professional knowledge, evidential standards, and current legislation. The paper discusses difficulties presented by deepfakes, highlighting the need for methods to authenticate digital evidence, and considers what UK legal remedies can protect the justice system and public from digitally falsified evidence. The paper concludes with potential recommendations for the justice system.


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Jones K. O., Jones B. S. How robust is the United Kingdom justice system against the advance of deepfake audio and video? Electrotechnica & Electronica (Е+Е), Vol. 57 (9-12), 2022, pp.103-109, ISSN: 0861-4717 (Print), 2603-5421 (Online)

20220508-full
Issue 5-8, 2022

ELECTROTECHNICA & ELECTRONICA E+E

Vol. 57. No 5-8/2022
Monthly scientific and technical journal
Published by:
The Union of Electronics, Electrical Engineering and Telecommunications /CEEC/, BULGARIA

20220508-full

C O N T E N T S

Special issue (second volume): scientific papers from 14-th International conference on Electron Beam Technologies – EBT 2022, Varna, Bulgaria
Preface by Prof. Elena Koleva, Bulgaria

ELECTRON BEAM WELDING
Colin Ribton, Paul Plumb
Laser heated cathodes for electron beam welding applications 51

Colin Ribton
Demagnetization of thick section steels for electron beam welding 56

Lilyana Koleva, Asya Lozeva, Elena Koleva
Optimization of electron beam welding of Ti-6Al-4V thin plates 62

Lilyana Koleva, Natalia Hristova, Elena Koleva
Simulation of electron beam welding of Inconel 718 thin plates 67

Elena G. Koleva, Lilyana S. Koleva
Robust model-based multicriterial optimization strategies for electron beam welding of Steel 45 72

20220508-01
Laser heated cathodes for electron beam welding applications
Colin Ribton, Paul Plumb

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Electron guns for processing applications typically use a thermionic cathode as the source of electrons, where the cathode is a resistively heated refractory metal ribbon. In order to keep the heat input to the gun reasonably low, a thin ribbon is desirable but is prone to distortion during use, and a ribbon of any thickness will evaporate at the temperatures required for electron emission, such that the surface will regress. The beam characteristics are dependent on the maintenance of tight dimensional tolerances around the cathode, so ribbon cathode lifetimes are often limited to some 12 hours. Changing the cathode necessitates equipment down time, and requalification of the equipment to verify its production readiness, leading to lower productivity. TWI have examined an alternative approach by using a button shaped cathode made of lanthanum hexaboride (LaB6). This material has a higher electron emissivity than refractory metals but at a temperature 1000C lower. As a consequence of this and the physical properties of LaB6, evaporation is negligible. The button was heated with a laser. The approach has been applied to a number of different electron guns, from 3 kW triodes at 60 kV up to a 15 0kV, 100 kW diode gun. Modelling and experimental work have been carried out on a number of cathode holder designs. The laser heated cathode system has been fitted to a number of commercially available electron beam systems for welding and powder bed additive manufacturing.


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Ribton C., Plumb P. Laser heated cathodes for electron beam welding applications. Electrotechnica & Electronica (Е+Е), Vol. 57 (5-8), 2022, pp.51-55, ISSN: 0861-4717 (Print), 2603-5421 (Online)

20220508-02
Demagnetization of thick section steels for electron beam welding
Colin Ribton

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High power electron beam welding can be applied to structures such as pressure vessels with wall thicknesses of up to 200 mm. Such applications often make use of steels that exhibit ferromagnetic properties. If the work pieces acquire a magnetic field, on assembly it has been found that reasonably strong external fields can be measured. Such fields do not need to be greater than 0.2 mT to cause an electron beam to be deflected, and such deflection can lead to missed joint defects at the cap or root of the weld. Correction of these weld defects in thick sections is costly.

This paper examines in detail the magnetic behavior of a steel frequently selected for nuclear plant – A508 grade 3. It has frequently been observed that this grade of steel can be more problematic to demagnetize, and beam deflection has been observed if no counter measures are taken. Special equipment has been designed to carry out the demagnetization of large segments, 200 mm thick and some 900 mm in length. A new approach has been taken to monitoring the magnetic field during the demagnetization cycle, which allows the effectiveness of the process to be assessed. Within this paper, magnetic modelling results, the demagnetization equipment, instrumentation and results are presented.


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Ribton C. Demagnetization of thick section steels for electron beam welding. Electrotechnica & Electronica (Е+Е), Vol. 57 (5-8), 2022, pp.56-61, ISSN: 0861-4717 (Print), 2603-5421 (Online)

20220508-03
Optimization of electron beam welding of Ti-6Al-4V thin plates
Lilyana S. Koleva, Asya Lozeva, Elena G. Koleva

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In this paper the electron beam welding of Ti–6Al–4V thin plates is simulated by implementation of a moving linear heat source model. The simulation results are used for estimation of regression models for the dependencies of molten pool geometry characteristics on the electron beam welding process parameters: electron beam power, welding velocity and the plate thickness. The optimization of electron beam of welding is considered in terms of minimization of the fusion zone geometrical parameters length, width and transverse cross-section area.


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Koleva L. S., Lozeva A., Koleva E. G. Optimization of electron beam welding of Ti-6Al-4V thin plates. Electrotechnica & Electronica (Е+Е), Vol. 57 (5-8), 2022, pp.62-66, ISSN: 0861-4717 (Print), 2603-5421 (Online)

20220508-04
Simulation of electron beam welding of Inconel 718 thin plates
Lilyana S. Koleva, Natalia Hristova, Elena G. Koleva

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In this paper the simulation of electron beam welding of Inconel 718 thin plates by a moving linear heat source is considered. Regression models for the molten pool geometry characteristics, depending on the electron beam power, welding velocity, and the thickness of the plates are estimated. These models are used for multi-criterial parameter optimization of the process electron beam welding.


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Koleva L. S., Hristova N., Koleva E. G. Simulation of electron beam welding of Inconel 718 thin plates. Electrotechnica & Electronica (Е+Е), Vol. 57 (5-8), 2022, pp.67-71, ISSN: 0861-4717 (Print), 2603-5421 (Online)