Engineering Proceedings, Volume 121, 2026

In submitting conference proceedings to Engineering Proceedings, the volume editors of the proceedings would like to certify to the publisher that all papers published in this volume have been subjected to peer review by the designated expert referee...

The subject of this study is the dynamic analysis of the energy flow in the transient mode of the movement of the vehicle with a kinetic accumulator, implemented with a purely mechanical transmission. The elements of which include—a flywheel, p...

This work examines the results of research into internal combustion engine malfunction using the example of a vehicle control group of a specific transport company during the warranty and post-warranty periods. Studies have established that the most...

This paper applies the recently developed Prediction-Based Control Barrier Functions (PB-CBFs) to the obstacle avoidance problem for multirotor air taxis in Urban Air Mobility (UAM). Unlike conventional Control Barrier Functions (CBFs), PB-CBFs incor...

This study investigates the aerodynamics of Romanian engineer Aurel Persu’s car through wind tunnel experiments involving force measurements, Particle Image Velocimetry (PIV), and CFD simulations. Tests using scale models revealed significant f...

Active Debris Removal (ADR) missions demand precise and rapid controllers that lower collision risks specifically in the capture phase of tumbling objects. Sliding Mode Control (SMC), in general, offers robustness against model uncertainties. However...

The article explores the current challenges and prospects for the electrification of the bus fleet in urban passenger transport, with a particular focus on the municipal operator Municipal Transport Ruse EAD. The study is motivated by the growing imp...

The current space law does not clarify the asteroid mining problem enough. This paper presents a techno-economic analysis to show how legal certainty impacts the profitability and overall investment in asteroid mining projects. Our analysis reveals t...

Recent progress in Reinforcement Learning (RL), especially deep RL, has created new possibilities for autonomous control in complex and uncertain environments. This study explores these possibilities through a practical approach, implementing an RL a...

This study develops a hyperbolic tangent-based model for the hysteretic behavior of automotive grade electrohydraulic semi-active dampers. Model parameters were identified from experimental force–velocity data gathered under sinusoidal excitati...

This paper presents a method for dimensional synthesis of a pulse-type adjustable speed mechanical drive, realized through a Watt II six-bar linkage combined with an overrunning clutch. The goal is to achieve a transmission ratio that varies smoothly...

The global energy landscape is transitioning towards cleaner solutions, with hydrogen emerging as a key energy source. To unlock hydrogen’s potential, it is crucial to prioritize the development of a more efficient, cost-effective, and environm...

This research simulates Aswan City’s urban transportation dynamics utilizing the Multi-Agent Transport Simulation (MATSim) framework. As a fast-expanding urban center, Aswan has many transportation difficulties that require extensive modeling t...

This study investigates the flow around Kline-Fogleman (KF) airfoils using Particle Image Velocimetry (PIV) in a wind tunnel at Reynolds number Re = 6.8 × 10⁴. Three configurations are tested: a clean NACA 0015 airfoil and two modified versions...

The current study presents results from experimental tests of productivity, fuel consumption, and fuel efficiency of a wheeled excavator Hyundai HW160A that were performed at a construction site in Sofia, Bulgaria. The experiments happened during the...

In recent years, Ammonia has emerged as a promising carbon-free fuel alternative, offering considerable potential to reduce CO₂ emissions and contribute to the decarbonization of the transportation industry. This study focuses on the economic feasibi...

The present literature review identifies substantial research and applied potential in the combined utilization of internationally recognized information security standards, Bayesian networks, and AI-based assistants to enhance cyber resilience in Un...

This study provides a comparison between the impact of two gas fuels, compressed natural gas (CNG) and hydrogen (H₂), on the exhaust emissions of a single-cylinder diesel engine operating in dual-fuel mode. The analysis is conducted with a constant a...

The paper investigates experimentally the influence of infill density, infill pattern, layer height, wall number, printing orientation, and material color on the impact strength of 3D-printed PLA (polylactic acid) samples by using the Charpy test met...

Side flaps are critical structural components of flat freight wagons, directly affecting cargo safety during transportation and playing an essential role in loading and unloading operations. Over the years, their reliability has been well established...

The BulTrans International Scientific Conference on Aeronautics, Automotive, and Railway Engineering and Technologies is organized by the Faculty of Transport, Technical University of Sofia [...]

Brake squeal is an undesirable high-frequency noise caused by vibrations induced by friction in disc brake systems. The noise is strongly affected by temperature, as this influences the material properties of the friction pair and the dynamic behavio...

In the context of promoting strategies to mitigate the global warming effect resulting from greenhouse gas emissions produced by human activities, ammonia stands out as an important player in the decarbonization of various sectors, including transpor...

This study presents a methodology used in the design certification of a battery module for electric vehicle applications. The methodology combines virtual and physical techniques to assess the structure under mechanical shock testing, according to th...

The distributor valve is one of the most important components in the pneumatic braking system of trains. It performs the functions of filling and releasing the brake cylinder. The distributor valve most widely used on Bulgarian railways operates in t...

This article describes the possibilities of using universal flat wagons to transport long cargoes and suggests measures for upgrading them, which involve the installation of superstructures on the load-bearing structures to keep the cargo from overtu...

This paper examines the application of Artificial Intelligence (AI) to protect satellite communication networks, focusing on the identification and prevention of cyber threats. With the rapid development of the commercial space sector, the importance...

Feeder buses play an important role in supporting the accessibility of high-speed railway stations which leads to the improved efficiency of the transportation system. This paper proposes a new optimization technique for the design of feeder bus rout...

The present paper investigates the dynamic behavior of an unbalanced rotor mounted in a balancing machine. Differential equations of motion are derived without linearization using Lagrange equations of the second kind to determine the nonlinear natur...

A new hybrid forecasting model of the number of freight trains is proposed in this paper. This forecasting is performed by combining classification analysis and the use of Histogram-based Gradient Boosting Regressor (HGBR). The freight trains were cl...

Nowadays, the automotive industry is primarily driven by the CO₂ policy that targets net zero carbon emissions by 2035 from passenger cars and commercial vehicles. The main path to achieve this goal is the implementation of electric powertrains with...

A removable module design is proposed to enable the use of open wagons for container transport. It acts as an intermediate adapter between an open wagon body and a tank container, ensuring the possibility of their reliable interaction. The dynamic lo...

This article represents a numerical approach for estimating the helicopter rotor’s blade longitudinal dynamic characteristics considering several operational parameters. A characterization regarding the blade’s longitudinal, flapping, and...