Browsing Acta Polytechnica. 2023, vol. 63 by Issue Date
Now showing items 1-20 of 42
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Estimation of stresses in a massive granite using laser ultra-sonic testing and stress memory effect
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)This paper addresses in-situ stress-estimation methods based on the Kaiser effect. The physical and mechanical properties of granite, diorite, and granodiorite samples selected at different depth intervals of the core ... -
Femtosecond laser processing of advanced technical materials
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)Ultra-short pulsed laser ablation may be used for high-precision machining with very low thermal influence on the processed materials. Due to this reason, lasers are increasingly used for processing of advanced materials, ... -
Self-interference cancellation in underwater acoustic communications systems using orthogonal pilots in IBFD
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)This paper proposes a Self-interference (SI) cancellation system model of Underwater acoustic (UWA) communication for in-band full-duplex (IBFD) technology. The SI channel is separated from the Far channel by exploiting a ... -
Heat transfer characteristics of double pipe heat exchanger having externally enhanced inner pipe
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)An investigation on enhancement of heat transfer is carried out for a double pipe heat exchanger in which the outer wall of the inner pipe is provided with circumferential labyrinth passages. Rectangular and triangular ... -
Induction motor mechanical defect diagnosis using DWT under different loading levels
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)The information extraction capability of the widely used signal processing tool, FFT for diagnosing induction machines, is commonly used at a constant load or at different levels. The loading level is a major influencing ... -
Comparative study of state space averaging and PWM with extra element theorem techniques for complex cascaded DC-DC Buck converter
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)Until now, most commonly used state space averaging and PWM techniques have been applied to different converter topologies and their advantages and disadvantages were stated. However, the superiority of an analytical ... -
Linearisation of a second-order nonlinear ordinary differential equation
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)We analyse nonlinear second-order differential equations in terms of algebraic properties by reducing a nonlinear partial differential equation to a nonlinear second-order ordinary differential equation via the point ... -
Parametric optimisation of friction stir welding on aluminium alloy (EN AW-1100) plates
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)Friction stir welding is a solid-state welding process used extensively for aluminium alloys. EN AW-1100 alloy is mostly used for its exceptional corrosion resistance, high ductility, high thermal and electrical conductivities, ... -
Multidimensional mobile mapping and integrated approach for the digitalisation of underground transport infrastructure
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)The tunnel industry has started focusing on the maintenance and management challenges of an existing infrastructure. It is an urgent matter in industrialised countries, where the stakeholders’ attention is increasing at a ... -
Case study: Dosimetric comparison of VMAT, IMRT and 3DCRT techniques for left-sided breast cancer treated in deep inspiration breath-hold
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)The aim of this case study was to compare 3D conformal radiotherapy (3DCRT) plans for patients treated for left-sided breast cancer (whole breast without positive lymph nodes in deep inspiration breath-hold (DIBH)) to ... -
Remapping and simulation of EFI system for SI engine using piggyback ECU
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)Electronic fuel injection (EFI) is a complex system, many parts are connected together from mechanical parts to electronic parts to control the internal combustion engine. It must ensure many different works and the most ... -
Utilising Pareto efficiency and RSM to adjust binder content in clay stabilisation for Yttre Ringvägen, Malmö
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)In this paper, we present a new framework for improving soil strength using an advanced method of engineering statistics. The materials included clay till collected in Yttre Ringvägen, southern Sweden. Binders included ... -
Exact solutions for time-dependent complex symmetric potential well
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)Using the pseudo-invariant operator method, we investigate the model of a particle with a time-dependent mass in a complex time-dependent symmetric potential well V (x, t) = if (t) |x|. The problem is exactly solvable and ... -
Derivation of entropy production in a fluid flow in a general curvilinear coordinate system
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)The paper deals with the derivation of the entropy production in the fluid flow performed in a general curvilinear coordinate system. The derivation of the entropy production is based on the thermodynamics laws as well as ... -
Neural network based patient recovery estimation of a PAM-based rehabilitation robot
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)Rehabilitation robots have shown a promise in aiding patient recovery by supporting them in repetitive, systematic training sessions. A critical factor in the success of such training is the patient’s recovery progress, ... -
Improving the energy efficiency of a tram’s running gear
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)This research analyses the influence of some design features of an undercarriage of a tram on the energy efficiency in terms of mechanical energy losses during its operation. The work includes the comparison of results of ... -
The effects of potassium permanganate on the geotechnical properties of soils
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)In Nigeria, potassium permanganate (KMnO4) is used as a chemical oxidant in the removal of hydrocarbons from polluted soils and groundwater, but there is no information on the effects of KMnO4 on the geotechnical properties ... -
From positional representation of numbers to positional representation of vectors
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)To represent real m-dimensional vectors, a positional vector system given by a non-singular matrix M ∈ ℤm×m and a digit set Ɗ ⊂ ℤm is used. If m = 1, the system coincides with the well known numeration system used to ... -
Qualitative sign stability of linear time invariant descriptor systems
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)This article discusses assessing the instability of a continuous linear homogeneous timeinvariant descriptor system. Some necessary conditions and sufficient conditions are derived to establish the stability of a matrix ... -
Fractional multi-loop active disturbance rejection control for a lower knee exoskeleton system
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2023)Rehabilitation Exoskeleton is becoming more and more important in physiotherapists’ routine work. To improve the treatment performance, such as reducing the recovery period and/or monitoring and reacting to unpredictable ...