Papers by Keyword: Kinetic Energy

Abstract: Structural robustness is vital to prevent disproportionate damage in a progressive collapse of a structure. Current assessment methods in building structures, such as the notional removal of structural members, are unable to capture cascading effects from debris impact loading and chained hazard scenarios. Vehicular impact with penetration into the building volume is an example of a plausible chained hazard scenario. In this study, the adequacy of notional damage methods was assessed for vehicular impact loading on building structures and a comprehensive framework was developed to address key limitations in conventional design methods against vehicular impact. The conventional approaches have relied on prescriptive forces and simplified models and have over-looked important phenomena, such as variable vehicle stiffness and energy dissipation mechanisms. The use of the vehicular impact framework has been exemplified using a model for progressive collapse to assess the consequences of successive time-delayed column loss on the structural response from the penetration of a lorry. The time-delay of successive column loss from vehicular impact was determined by considering the kinetic energy and energy dissipation mechanisms. Higher initial velocities lead to higher post-impact velocities after the initial impact on a column and to a reduction in time between successive failures, thus heightening the likelihood of cascading failures in structural columns and progressive collapse. Progressive collapse simulations revealed that a building structure may have sufficient robustness to prevent progressive collapse when subjected to the loss of single columns. However, successive column losses triggered an extensive progressive collapse.

Abstract: This scientific study presents experimental results of particle agglomeration and dispersing processes under various physicochemical conditions, focusing on the effects of temperature, particle concentration, and medium viscosity. Using numerical approaches and experimental data, patterns describing the changes in agglomeration rate and the features of dispersing system stability were identified. The key findings of the research include: the influence of temperature on agglomeration, high particle concentration, medium viscosity, dispersion under low particle concentration conditions. It is noteworthy that the results also confirm an exponential dependence of the agglomeration rate on temperature. However, at high particle concentrations, this effect is mitigated by the dominance of interparticle interactions, such as Van der Waals forces and electrostatic effects. Furthermore, in systems with low particle concentration and elevated temperature, agglomeration processes significantly slow down, indicating improved dispersing stability. The study opens new perspectives for controlling particle agglomeration and dispersing based on temperature, concentration, and the physical properties of the medium. The obtained data can be useful for improving existing technologies and developing new ones in areas where controlling the behavior of dispersed systems is essential.

Abstract: The article presents the design and discusses the operating principle of a planetary roller gear with a satellite performing spherical motion. A comparative analysis of gears of eccentric and spherical types with the same kinematic and comparable geometric parameters was carried out. The comparison criterion is kinetic energy. Dependencies were obtained to determine the kinetic energy for both types of gears on the gear ratio, angular velocity of the driving link and geometric parameters. It has been established theoretically and confirmed by the results of computer modeling that the use of a spherical gear instead of a flat one makes it possible to reduce the radial dimensions of the drive, reduce energy consumption (starting torques) by 3...5 times and dynamic pressures in the satellite supports by 1,8 times.

Abstract: Advancements in imaging systems including Electronic Portal Imaging Devices (EPIDs) play a great role in radiotherapy treatment. It was developed as a verification tool for patient setup during radiotherapy sessions and also become a promising tool for the determination of the accurate placement of radiation beams. However, as part of quality assurance, individual patient treatments are often verified by patient-specific quality control measurements such as before treatment (pretreatment) or during treatment (in vivo). It has been shown that in vivo dosimetry using an electronic portal imaging device (EPID) is an effective QC tool to detect errors and this method has been clinically applied to various treatments. The introduction of advanced EPID technology has led to an interest in its application for dose conformation and dose deposition. Moreover, dose deposition is subject to uncertainties due to several factors, including the presence of secondary particles. Thus, knowing the physical processes that produced the secondary particles as well as their average kinetic energy will help to provide valuable information about the effective filtering of these particles or the possible use of these particles for other applications. In this study, Monte Carlo simulations are performed to determine the average kinetic energy of detected secondary particles, specifically photons, electrons, and positrons produced by each particular physical interaction as a function of detector position using GATE v9.0. The virtual radiotherapy set-up is composed of the box water phantom, which is the target in the simulations with a dimension of 20 cm × 20 cm × 20 cm, an EPID system (detector), and a beam source in which it uses three (3) beams situated at varying positions with an energy of 6 MeV. The monoenergetic pencil beam source is placed 90 cm away from the center of the target and is directed toward the target (+x-axis) while the EPID (detector) is set as 120 cm SDD (source-to-detector distance). Moreover, the photon beam with 10 million primaries is set with varying field sizes of 1 cm × 1 cm, 3 cm × 3 cm, 6 cm × 6 cm, and 9 cm × 9 cm. Overall, the results show that the highest average kinetic energy among secondary particles produced by each physical interaction are electrons coming from Compton scattering (∼ 3 MeV), followed by positrons and electrons from pair production (∼ 2.4 MeV), photons from annihilation and bremsstrahlung (∼ 0.5 MeV), and electrons from ionization (∼ 0.13 MeV).

Abstract: . The flow pattern on the combined effect of a horizontal cylinder and a vertical plate is observed and analysed in this experimental study. The experiment was conducted with a 4 cm outer diameter cylinder arranged horizontally across flow above 2 cm from the bed and a vertical plate of 5 cm placed 9 cm downstream from cylinder surface reference as tilting flume bed surface. The water depth was maintained at 17 cm through a constant discharge of 35 lps in a re-circulating flume. Acoustic Doppler Velocimeter (ADV) was used to store the velocity fluctuation of velocity components and further used as a pictorial frame to understand the turbulence and the turbulent kinetic energy around the cylinder, plate and in between the cylinder - vertical plate. From the pictorial contour diagrams drawn, the velocity vector represents the flow feature over the cylinder and it is found that a horseshoe vortex, developed upstream of the plate, does effect on turbulent kinetic energy formed in between cylinder and vertical plate. The observation and obtained results from present study is compared with a 5 cm horizontal cylinder above 2 cm from the bed and a plate situated on 5.5 cm from cylinder curvature towards downstream.

Abstract: The aim of this article is to highlight the impact of the fuel movements inside the plastic fuel tank (waves) for the client perception of noise. Today there isn’t a clear methodology regarding the reproducing the fuel waves, but there are different approaches to be taken into account and also there is an innovative potential. Due to the fast technological progress the body in white and not only, the entire vehicle became lighter and lighted. A consequence of this great achievement is that the client can hear easier the sound produced by different components of the car. The plastic fuel tank can be considered such a component. The authors have done a deep analysis of present automotive fuel tanks and propose solutions for breaking the waves produced inside fuel tanks, so as to reduce the slosh noise effect. The studies will be continued during the doctoral approach of the first author.

Abstract: The recent vehicle management systems have been developing to improve the quality of the combustion process and transmission systems. In thermodynamic approach, the water molecule can exists in different phases like ice, water, wet steam, dry steam, and superheated steam. The phase change occurs in the steam formation process can be compared to the various stages of any vehicle dynamic system such starting, idling, normal speed, high speed and very high speed. There may be an identical value in the increment of energy level in both steam formation process and any vehicle dynamic system. Thermodynamic approach always deals with system, surroundings, boundary and energy transformation across boundaries. Entropy is a very good property which is used to find the energy degradation in a particular system, and this property existence in the vehicle dynamics of automobiles will be used to improve the efficiency of the control module of a vehicle management system. This paper initiates a new angle research in the field of vehicle dynamics to study and investigate the kinetic energy transformation and distance moved by the vehicle thermodynamically. From this paper, Entropy is found as a very good property for increasing the mileage of the vehicle. In the vehicle health monitoring, there should be an entropy measurement to reduce the unavailability of energy as it is the measure of the distance travelled by the vehicle per unit energy supplied to the same vehicle at various operating speeds. In manual transmission method, it has been found that driver is not able to press the accelerator pedal continuously due to body strain. Driver has to run the vehicle at constant speed by pressing the accelerator pedal continuously. In automatic transmission, the data required for the ECU module is given by the thermodynamic relations such as enthalpy, entropy and internal energy. This paper aims thermodynamically to describe the speed, acceleration, fuel consumption, kinetic energy and various resistances offered to the vehicles. Generally, Thermodynamic system deals with heat and mass transfer, likewise vehicle dynamics deals with work and vehicle’s motion.

Abstract: The mechanosynthesis of Ni₃Fe intermetallic compound was carried out in a planetary mill. The effects of milling parameters such as balls diameters and ball milling speed defined by the vials rotation speed (ω) and the disk rotation speed (Ω), on morphology, microstructure and particle sizes of Ni₃Fe powder were studied. It was found that the impact frequency represented by the number of balls from vials is an important parameter a milling process. The smaller grain sizes and particle was obtained when milling process was performed in high frequency rate of impacts together with high balls velocity, meaning high energy conditions.

Abstract: The vibration energy harvesting from raindrop is an interesting and potential approach for future applications. This article presents the piezoelectric based beam length optimization for raindrop energy harvesting application. In this work, polyvinylidene fluoride (PVDF) is selected as piezoelectric material. The characteristics and performances of the beam are experimentally investigated. It includes investigation on the impact of water droplets with 4.3 mm diameter, released from 0.25 m heights at various lengths of PVDF beam. The width and thickness of the beam are fixed to 4 mm and 25 μm respectively. Results showed that the optimized length which is 30 mm is possible to generate peak voltage up to 8.5 V.

Abstract: Through an underwater camera at the WES Weir of the Dayuandu Project, the heavy sedimentation on the Weir’s floor can be observed. The sediment changes the water flow patterns before the Weir, resulting in Weir surface wear and sluice leakage. Mathematical models and physical had been builded to analyze the effect of the erosion. The results of these observations provide a reasonable and effective scheduling method to solve the siltation problems in front ofthe WES Weir. Once there are sufficient flow intensity, the ternary complex flow patterns will contribute to the incipient motions of sediment, acquireing desirable effect of sedimentation Control.