ENGINEERING OF SEMICONDUCTOR COMPOUNDS VIA ELECTROCHEMICAL TECHNOLOGIES FOR NANO-MICROELECTRONIC APPLICATIONS

https://doi.org/10.52326/jes.utm.2022.29(1).01

UDC 621.382:546:621.3.049.77

Eduard Monaico

Abstract. The paper is focused on electrochemical approaches for nanostructuring of semiconductor compounds with further applications in nano – microelectronic devices. A cost-effective technology for nanowires and nanotubes obtaining by pulsed electrochemical deposition is presented. Functionalization of elaborated nanostructures with gold or platinum via electroplating improves the properties of the nanostructures. An optimization of the varicap design to increase the capacitance is proposed and discussed as well as the optimization of pulsed electrochemical deposition of several hundred micrometer long Pt nanotubes is performed. Herein, the elaboration of contacts to GaAs nanowires via different approaches for photoelectrical investigations is reported.

Keywords: electrochemistry, nanostructures, nanowires, photodetector, contacts, varicap device.

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GENERATION OF HIGH AMPLITUDES PULSES WITH EXCITABLE DFB LASERS AND AN INTEGRATED DISPERSIVE REFLECTOR

https://doi.org/10.52326/jes.utm.2022.29(1).02

UDC 621.375.826

Silvia Andronic, Eugeniu Grigoriev, Vasile Tronciu

Abstract. This paper is devoted to investigation of pulse generation by a distributed feedback (DFB) laser with an integrated passive dispersive reflector. This configuration is treated in the framework of the simple rate equation model for dimensionless carrier and photon numbers. The two functions describe the influence of reflector on the laser dynamics. The theoretical results show that under certain condition the laser is operating in excitable regime suitable for pulse generation. We have identified the appropriate values of parameters for pulse generation. We apply small perturbation to the system in order to generate periodic pulses. Finally, the influence of these parameters on shape of pulses is investigated.

Keywords: DFB laser, passive dispersive reflector, excitability, pulse generation.

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THEORETICAL CONTRIBUTIONS ON THE SELECTION OF POSSIBLE TRIBOLOGICAL COUPLES OF MATERIALS FOR THE MANUFACTURE OF PRECESSIONAL TRANSMISSIONS

https://doi.org/10.52326/jes.utm.2022.29(1).03

UDC 621.83:678.073

Ion Bostan, Petru Stoicev, Alexandru Buga, Gheorghe Postaru, Nicolae Trifan, Andrei Platon

Abstract. Selecting gear materials is a great challenge for engineers. Gear teeth are subject to difficult and severe loading conditions. Simultaneous action of alternating normal and tangential dynamic stresses occurs, contact deformations accompanied by sliding friction. Gears are subject to increased requirements in terms of strength, geometric accuracy, dimensional stability, and durability. For the manufacture of gears, especially from thermoplastic materials, a theoretical argumentation of the materials is needed. An extensive study of thermoplastic materials, around the world needs to be done and the most efficient tribological couples to be chosen in terms of heat transfer from the gear zone, operation with or without lubrication, and gear life. In this paper, a theoretical synthesis of the Steel / Plastic, Plastic / Plastic, Plastic/Steel tribological couples is made, which were used in conformist and non-conformist experiments. Therefore, selected tribological couples are supposed to be used in the Precessional Transmissions applications.

Keywords: gear materials, sliding friction, manufacture of gears, thermoplastic materials, heat transfer, tribological couples, gear life, theoretical synthesis.

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DRIVER OR AUTOPILOT – WHO IS THE FUTURE

https://doi.org/10.52326/jes.utm.2022.29(1).04

UDC 656.13.08

Vasile Plămădeală, Sergiu Dîntu

Abstract. The human factor is the main element in the production of road events, not only in terms of percentage, but also in absolute importance, because, ultimately, road and technical issues are involved in road accidents only in strict accordance with the behavior and the direct action of the driver, who, within the road traffic system, is more variable and unpredictable than the vehicle, road and environmental factors. The driver is guilty of 70-90% of the total number of road accidents. More than a third of people killed and injured in road accidents worldwide are drivers. The article describes the role of the driver in the DVRE system, the risk factors and the causes contributing to the occurrence of road accidents. A brief analysis of road accident statistics due to drivers in the Republic of Moldova and around the world is performed. It also describes the evolution of the unmanned car and other innovative technologies and ideas for automating car driving.

Keywords: driver, autopilot, road accidents, traffic accidents, traffic safety.

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THE TRANSITION TO A HYDROGEN ECONOMY

https://doi.org/10.52326/jes.utm.2022.29(1).05

UDC 662.769.2:620.9

Titu-Marius I. Băjenescu

Abstract. The article examines the problem of the hydrogen market – from production to how to use it, as well as the prospects for the development of these energy sources. To combat climate change, more and more countries are investing in low-carbon energy, which is produced from renewable sources and is therefore neutral throughout the chain. Thus, the global hydrogen market is growing. Hydrogen can help decarbonise industrial sectors and combat climate change, either as an environmentally friendly fuel in the transport sector or as a means of reducing emissions in steel production and many other industries. Hydrogen can also play a vital role in energy transport. But even though hydrogen does not pollute itself, because its combustion releases only water vapour, it emits CO2 when fossil fuels are used for its production (“Grey” hydrogen). “Green” hydrogen is still in its infancy: less than 1% of global hydrogen production, which is itself only 2% of global energy consumption. “Green” hydrogen is very expensive to produce, considerably more than “Grey” hydrogen.

Keywords: Hydrogen energy, ”Green hydrogen”, “Grey” hydrogen, present challenge, Hydrogen economy, CO2-free hydrogen, Use of hydrogen.

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SYSTEMS FOR INVARIANT TARGET RECOGNITION BASEDON CENTRAL IMAGE CHORD TRANSFORMATION

https://doi.org/10.52326/jes.utm.2022.29(1).06

UDC 623.4.021:004.6

Veaceslav Perju

Abstract. Target recognition (TR) is widely used in different military and civil applications and permits enhanced intelligence and autonomously operating platforms design. The article describes existing systems for TR such as deep learning aided computer vision; target tracking architecture, based on the tracking-by-detection paradigm; a target detection dataset; deep neural networks; a system for the management of a plurality of sensors; a target recognition architecture, adaptive to operational conditions and a target detection system, based on the theory of multi-temporal recognition. Unfortunately, the existing systems do not orient for real-time processing or can be applied for synthetic aperture radar images only, or used for image processing of soft targets, etc. This article presents the data regarding proposed new systems for targets recognition and determination of their parameters, based on central image chord transformation. The systems’ main processing units are described. The structures of the elaborated systems and the principles of their functioning are presented. The models of data processing flow in the systems are described. The determination of the processing time of the operations, realized in the systems was made and the estimation of the throughput of the systems was done. The optimization of the elaborated systems was made. The results regarding systems’ characteristics are presented.

Kew words: Target recognition, data processing flow, throughput, optimization.

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ELABORATION AND APPLICATION OF GRAPHICAL MODELS TO OPTIMIZE THE RESPONSE TIME TO EMERGENCY SITUATIONS

https://doi.org/10.52326/jes.utm.2022.29(1).07

UDC 614.8.084

Serghei Peancovschii

Abstract. This article presents methods for timing the key milestones and timing of the emergency response. A graphic model is proposed that allows you to determine the stage and time of the response process, regardless of the nature of the ongoing processes manifestation. The model allows a detailed analysis the process effectiveness of responding to various emergencies. And it also allows to determine the boundaries of responsibility areas to optimize management decisions of the response process, increasing its quantitative and qualitative values. The presented mathematical models exclude errors in assessing the effectiveness of the response. The developed mathematical apparatus can be used for effective management of emergency response units.

Keywords: decision making, safety, timing, emergency situations, areas of responsibility, emergency response.

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PROOF-OF-STAKE CONSENSUS ALGORITHMS FOR THE SOFTWARE COMPONENTS BLOCKCHAIN

https://doi.org/10.52326/jes.utm.2022.29(1).08

UDC 004

Vaidas Giedrimas

Abstract. In the blockchain context, the information system (IS) is considered a part of its infrastructure. However, blockchain itself can be used for IS development using software components and services. As the trust for binary components or services is still a problem, we propose to use the blockchain of components to solve this problem. In this paper, the part of such solution, namely consensus algorithms, is discussed. We focus on Proof-of-Stake algorithms and present their feasibility to be used in the blockchain of software components. It was found that the use of probabilistic algorithms (RRR, CloudPoS, WV, DDPoS, Panda) allow the partial solution of the problem in the blockchain of reliable software components.

Keywords: software component, CBSE, consensus algorithm, blockchain.

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ERGONOMIC INVESTIGATION AND ASSESSMENT OF MOTORCYCLISTS MUSCULOSKELETAL DISORDERS

https://doi.org/10.52326/jes.utm.2022.29(1).09

UDC 616.7:656.18.05: 331.101.1(669)

Adekunle I. Musa-Olokuta, Collins Nwaokocha, Adeola S.Shote, Samson A. Aasa

Abstract. Motorcycles have become a mean of transportation in our rural and urban area in Nigeria. This cross sectional study was conducted in Abeokuta Ogun State to assess the work-related musculoskeletal disorders (WRMSDs) among the motorcyclist between October 2021 and January 2022 using snowball techniques. A structured modified Nordic Musculoskeletal disorder questionnaire (SNMQ) was administered to four hundred and fifty (450) motorcyclists. The result shows that 91.6% (412) of the motorcyclist participated. Furthermore, 76.1% of the cyclist experienced daily pains and 81.6% reported major pains in body parts. However, the results also show that major affected body regions were lower back (81.6%), leg (61.2%), upper back (82.0%), shoulder (55.1%), neck (82.5%), knee (73.3%), wrist/hand (98.8%), thigh (91.3%), ankle/feet (78.9%), ears (80.3%), eyes (59.0%), head (63.1%) respectively. The study concluded that high prevalence of WRMSDs existed among the commercial motorcyclists as a result of working hours, sitting posture, smoking and alcoholic drinking. Reduction of these symptoms could be achieved through the reduction of working hours.

Keywords: WRMSDs, motorcyclist, smoking, alcohol, tiredness, break, shoulder, thigh.

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