scholarly journals Mathematical Model for Velocity Calculation of Three Types of Vehicles in the Case of Pedestrian Crash

2018 ◽  
Vol 68 (3) ◽  
pp. 95-110
Author(s):  
Hoxha Gëzim ◽  
Shala Ahmet ◽  
Likaj Ramë ◽  
Bajrami Xhevahir
Keyword(s):  
Mathematical Model ◽  
Accurate Determination ◽  
Geometrical Parameters ◽  
Vehicle Speed ◽  
Model Formulation ◽  
Vehicle Velocity ◽  
Pedestrian Accidents ◽  
Throw Distance ◽  
Front Profile

AbstractThis paper treats influencing factors in the determination of vehicles speed on the pedestrian crash moment according to pedestrian throw distance and formulates a mathematical model for vehicle speed determination. Vehicle speed is one of the highest causes of accidents. The mathematical model formulation (as the target of this paper) for velocity calculation, in the case of pedestrian accidents, presents great help and guidance to experts of this field when dealing with accident analysis that through accurate determination of this parameter to find other circumstances as close as possible to the technical process of pedestrian accidents. The target of this paper is to define a mathematical model formulation for vehicle velocity calculation in pedestrian crash moment depending on relevant parameters. For the purpose of model formulating, we have selected three cases of real accidents that involved vehicles (“Peugeot 307”, “VW Golf ” and “Mercedes E 220”) with different geometrical parameters of the front profile and pedestrians with different heights and weights. For regression analysis we used “R” and “SPSS” software, which enables the statistical analysis of the data and mathematical model formulation. Also, for analysis of impact of relevant factors, model formulation and model testing have used “Virtual Crash” and “PC Crash” software, which enables pedestrian-vehicle crash simulation using vehicles with real technical characteristics and various pedestrian characteristics. Inductive, comparative, and deductive methods are part of the research methods in this paper.

scholarly journals Roll Attitude Determination of Spin Projectile Based on GPS and Magnetoresistive Sensor

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Dandan Yuan ◽  
Wenjun Yi ◽  
Jun Guan
Keyword(s):  
Mathematical Model ◽  
Attitude Determination ◽  
Accurate Determination ◽  
Blind Spot ◽  
Gps Measurements ◽  
Guidance And Control ◽  
Magnetoresistive Sensor ◽  
Proposed Model ◽  
And Control

Improvement in attack accuracy of the spin projectiles is a very significant objective, which increases the overall combat efficiency of projectiles. The accurate determination of the projectile roll attitude is the recent objective of the efficient guidance and control. The roll measurement system for the spin projectile is commonly based on the magnetoresistive sensor. It is well known that the magnetoresistive sensor produces a sinusoidally oscillating signal whose frequency slowly decays with time, besides the possibility of blind spot. On the other hand, absolute sensors such as GPS have fixed errors even though the update rates are generally low. To earn the benefit while eliminating weaknesses from both types of sensors, a mathematical model using filtering technique can be designed to integrate the magnetoresistive sensor and GPS measurements. In this paper, a mathematical model is developed to integrate the magnetoresistive sensor and GPS measurements in order to get an accurate prediction of projectile roll attitude in a real flight time. The proposed model is verified using numerical simulations, which illustrated that the accuracy of the roll attitude measurement is improved.

scholarly journals Methodology for determining the parameters of drilling mode for directional straight sections of well using screw downhole motors

2020 ◽  
Vol 241 ◽  
pp. 105 ◽  
Author(s):  
V. Litvinenko ◽  
M. Dvoinikov
Keyword(s):  
Mathematical Model ◽  
Stable Operation ◽  
Geometrical Parameters ◽  
Directional Drilling ◽  
Optimal Parameters ◽  
Combined Method ◽  
Steady State Operation ◽  
Drilling String ◽  
Simultaneous Rotation

Article presents results of study on possibility of increasing the efficiency of drilling directional straight sections of wells using screw downhole motors (SDM) with a combined method of drilling with rotation of drilling string (DS). Goal is to ensure steady-state operation of SDM with simultaneous rotation of DS by reducing the amplitude of oscillations with adjusting the parameters of drilling mode on the basis of mathematical modeling for SDM – DS system.Results of experimental study on determination of extrema distribution of lateral and axial oscillations of SDM frame depending on geometrical parameters of gerotor mechanism and modes ensuring stable operation are presented.Approaches to development of a mathematical model and methodology are conceptually outlined that allow determining the range of self-oscillations for SDM – DS system and boundaries of rotational and translational wave perturbations for a heterogeneous rod with an installed SDM at drilling directional straight sections of well. This mathematical model of SDM – DS system's dynamics makes it possible to predict optimal parameters of directional drilling mode that ensure stable operation of borehole assembly.  

scholarly journals A Street Graph-Based Morphometric Characterization of Two Large Urban Areas

2021 ◽  
Vol 13 (3) ◽  
pp. 1025
Author(s):  
Luca Salvadori ◽  
Maria Grazia Badas ◽  
Annalisa Di Bernardino ◽  
Giorgio Querzoli ◽  
Simone Ferrari
Keyword(s):  
Aspect Ratio ◽  
Urban Areas ◽  
Accurate Determination ◽  
Geometrical Parameters ◽  
Urban Microclimate ◽  
Area Index ◽  
Planar Area ◽  
Morphometric Characterization

Urban microclimate modelling, both numerical and in the laboratory, has strong implications in many relevant health and life-style management issues e.g., in studies for assessment and forecast of air quality (for both outdoor and, as boundary conditions, indoor investigations), for thermometric trend analysis in urban zones, in cultural heritage preservation, etc. Moreover, the study of urban microclimate modelling is largely promoted and encouraged by international institutions for its implication in human health protection. In the present work, we propose and discuss an adaptive street graph-based method aimed at automatically computing the geometrical parameters adopted in atmospheric turbulent flow modelling. This method has been applied to two real cases, the Italian cities of Rome and Cagliari, and its results has been compared with the ones from traditional methods based on regular grids. Results show that the proposed method leads to a more accurate determination of the urban canyon parameters (Canyon Aspect Ratio and Building Aspect Ratio) and morphometric parameters (Planar Area Index and Frontal Area Index) compared to traditional regular grid-based methods, at least for the tested cases. Further investigations on a larger number of different urban contexts are planned to thoroughly test and validate the proposed algorithm.

scholarly journals A New Mathematical Model for the Accurate Determination of Volatile Fatty Acids Concentration in Anaerobic Digesters

2020 ◽  
Vol 06 (02) ◽  
pp. 67-84
Author(s):  
Gaston Nsavyimana ◽  
Salvator Kaboneka ◽  
Casimir Harerimana ◽  
Chema Keffala ◽  
Marc Elskens ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Accurate Determination ◽  
Anaerobic Digesters

scholarly journals Numerical Analysis of Switching Processes in Class D Modulators

2021 ◽  
Vol 7 (1) ◽  
pp. 71-80
Author(s):  
V. Nikolaev ◽  
E. Rylov ◽  
D. Devyatkin ◽  
R. Nikolaev
Keyword(s):  
Mathematical Model ◽  
Optimal Control ◽  
Numerical Analysis ◽  
Output Voltage ◽  
Accurate Determination ◽  
Power Losses ◽  
Active Devices ◽  
Current Pulses ◽  
Class D

The article investigates the switching processes in class D modulators for optimal control of active devices (transistors, triodes, tetrodes, etc.) in real conditions, to reduce power losses in them and non-linear distortions of the modulator output voltage, as well as more accurate determination of the devices efficiency. The presented mathematical model takes into account the inertia of the switching processes, the duration of the rise and fall fronts of voltage and current pulses, as well as losses in switching elements.

scholarly journals Mathematical Model Describing the Influence of Geometrical Parameters of Multichannel Dies on the Limit Force of Dry Ice Extrusion Process

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3317
Author(s):  
Jan Górecki ◽  
Krzysztof Talaśka ◽  
Krzysztof Wałęsa ◽  
Dominik Wilczyński ◽  
Dominik Wojtkowiak
Keyword(s):  
Mathematical Model ◽  
Compressive Force ◽  
Extrusion Process ◽  
Physical Characteristics ◽  
Geometrical Parameters ◽  
Actual Measurement ◽  
Dry Ice ◽  
Measurement Results ◽  
The Difference

The article presents a formulated mathematical model that enables the determination of the required compressive force in the extrusion process of dry ice employing multichannel dies. This is the main parameter in the piston-based dry ice extrusion process. The indicated model was developed for the purpose of further improvement of the energy efficiency of this extrusion process. It allows for the determination of the value of compressive force by accounting for 12 variables related to the geometrical parameters of the die and the physical characteristics of dry ice. Furthermore, the paper also provides descriptions of the empirical study methodologies together with the results. These were carried out in order to determine the difference between the results of mathematical modeling and actual measurement results. The final part of the article presents the results of the analysis of the mathematical model’s sensitivity to the change of the physical characteristics of dry ice. The formulated tool may be employed to adapt the geometric parameters of the die in order to obtain the desired compressive force value and dry ice granulation with reduced energy consumption.

scholarly journals Investigation of the Fluid Dynamics of Lubrication in the Gaps of the Gas Distribution Mechanism of the Internal Combustion Engine

2021 ◽  
pp. 34-39
Author(s):  
Alexander Vasilyev ◽  
◽  
Evgenij Ageev ◽  
Keyword(s):  
Fluid Dynamics ◽  
Mathematical Model ◽  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Accurate Determination ◽  
Internal Combustion ◽  
Exhaust Valve ◽  
Gas Distribution ◽  
Engine Exhaust

The method of calculating the fluid dynamics of the lubricant in the gaps is considered on the basis of a generalized mathematical model of the dynamics of the gas distribution mechanism. The results of its use for the drive of the engine exhaust valve are presented. It is shown that the developed methods and algorithms provide a more accurate determination of the dynamic and tribological characteristics of the gas distribution mechanism.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Fast calibration of CBED patterns for quantitative analysis

1993 ◽  
Vol 51 ◽  
pp. 674-675
Author(s):  
M.A. Gribelyuk ◽  
M. Rühle
Keyword(s):  
Reciprocal Lattice ◽  
Accurate Determination ◽  
Incident Beam ◽  
Crystal Thickness ◽  
Structure Model ◽  
Beam Direction ◽  
Transmitted Beam ◽  
Reciprocal Vector ◽  
On Line

A new method is suggested for the accurate determination of the incident beam direction K, crystal thickness t and the coordinates of the basic reciprocal lattice vectors V1 and V2 (Fig. 1) of the ZOLZ plans in pixels of the digitized 2-D CBED pattern. For a given structure model and some estimated values Vest and Kest of some point O in the CBED pattern a set of line scans AkBk is chosen so that all the scans are located within CBED disks.The points on line scans AkBk are conjugate to those on A0B0 since they are shifted by the reciprocal vector gk with respect to each other. As many conjugate scans are considered as CBED disks fall into the energy filtered region of the experimental pattern. Electron intensities of the transmitted beam I0 and diffracted beams Igk for all points on conjugate scans are found as a function of crystal thickness t on the basis of the full dynamical calculation.

Computer-Assisted High-Re Solution TEM

1990 ◽  
Vol 48 (1) ◽  
pp. 162-163
Author(s):  
F.A. Ponce ◽  
H. Hikashi
Keyword(s):  
Signal To Noise Ratio ◽  
Accurate Determination ◽  
Computer Software ◽  
Video Camera ◽  
Image Contrast ◽  
Objective Lens ◽  
Computer Assisted ◽  
Optical Parameters ◽  
Astigmatism Correction

The determination of the atomic positions from HRTEM micrographs is only possible if the optical parameters are known to a certain accuracy, and reliable through-focus series are available to match the experimental images with calculated images of possible atomic models. The main limitation in interpreting images at the atomic level is the knowledge of the optical parameters such as beam alignment, astigmatism correction and defocus value. Under ordinary conditions, the uncertainty in these values is sufficiently large to prevent the accurate determination of the atomic positions. Therefore, in order to achieve the resolution power of the microscope (under 0.2nm) it is necessary to take extraordinary measures. The use of on line computers has been proposed [e.g.: 2-5] and used with certain amount of success.We have built a system that can perform operations in the range of one frame stored and analyzed per second. A schematic diagram of the system is shown in figure 1. A JEOL 4000EX microscope equipped with an external computer interface is directly linked to a SUN-3 computer. All electrical parameters in the microscope can be changed via this interface by the use of a set of commands. The image is received from a video camera. A commercial image processor improves the signal-to-noise ratio by recursively averaging with a time constant, usually set at 0.25 sec. The computer software is based on a multi-window system and is entirely mouse-driven. All operations can be performed by clicking the mouse on the appropiate windows and buttons. This capability leads to extreme friendliness, ease of operation, and high operator speeds. Image analysis can be done in various ways. Here, we have measured the image contrast and used it to optimize certain parameters. The system is designed to have instant access to: (a) x- and y- alignment coils, (b) x- and y- astigmatism correction coils, and (c) objective lens current. The algorithm is shown in figure 2. Figure 3 shows an example taken from a thin CdTe crystal. The image contrast is displayed for changing objective lens current (defocus value). The display is calibrated in angstroms. Images are stored on the disk and are accessible by clicking the data points in the graph. Some of the frame-store images are displayed in Fig. 4.

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