National Repository of Grey Literature 36 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Identification of Relevant Tire Traces in Traffic Accident Place Based on their physical characteristics
Bilík, Martin ; Kovanda, Jan (referee) ; Kledus, Robert (referee) ; Bradáč, Albert (advisor)
The thesis deals with the possibilities of identifying the relevant tire traces at the place of a traffic accident based on their physical characteristics. Braking traces on the road are one of the most important objective elements for accident analysis, their easy and accurate detection is very important for accurate accident assessment. With the increasing technical equipment of vehicles, especially with the introduction of newer generations of braking assistance systems, traces left by the tires become almost invisible to the human eye. It is therefore highly desirable that their detection should be not only as accurate as possible but also as easy and fast as possible, not only for forensic experts, but especially for members of the traffic police departments. In line with the development and introduction of new safety and assistance systems for vehicles should also be the development of means and methods of providing the basis for technical analysis of traffic accidents. Reality shows that the procedures, even if still functional, are practically identical for several decades, are dependent on the subjective capabilities of the documenting person. An essential element of the work, compared to the previously described measurement procedures, is the use of modern methods and devices at the highest known level of knowledge. The aim is to find and verify a simple, accurate, subjectively least influenced detecting method for tire traces on the road. A series of measurements confirmed the possibility of using the thermal camera at the technical level usually available at the place of the accident, under limited atmospheric and time conditions. In addition, laser-induced plasma spectroscopy and rLIBS were used. This method of detecting spotless tire treads can be marked as a minimally feasible documentary and at the same time as fast enough, based on the measurements made and the intended removal of defects of the instrument in the development phase of the prototype.
Injury mechanisms of the extreme load
Purš, Hynek ; Kovanda, Jan (advisor) ; Palčák, František (referee) ; Kadleček, Boleslav (referee)
SUMMARY: This dissertation is focused on the biomechanics of extreme loads. Experiments in this area are very difficult to implement, they are usually based on the extrapolation of the measurements provided with volunteers, PMHS, etc. The project is based on the assumption that traffic accidents generate loads that correspond to a definition of extreme loading. Their mathematical simulations allow us to map and evaluate them. This dissertation covers three areas: pedestrian accidents, side impact of a child and whiplash injuries. The thesis presents a detailed analysis of selected processes including sensitivity analysis of impact conditions and of impactor parameters. Problem: The main task is to deal with the problem of description and analysis of extreme loads. It is focused on traffic accidents and their analysis is performed by a computer simulation. Hypothesis: An analysis of accidents by a computer simulation is an adequate tool to determine human body tolerance to extreme loadings. Objective: Utilisation of available data from selected traffic accidents and of their subsequent simulation to determine extreme loads of people during traffic accidents. Method: The chosen method is a computer simulation. The multibody dynamics is an analysis tool of a collision with a pedestrian. The finite element...
Analysis of set of factors affecting safe longitudinal distance between vehicles
Zemánek, Lukáš ; Kovanda, Jan (referee) ; Bradáč, Albert (referee) ; Vémola, Aleš (advisor)
The doctoral thesis deals with problems of a safe longitudinal distance between vehicles. It includes an analysis of a set of factors influencing the safe distance between vehicles and is concerned with a research of effect of many of these factors on observance of the safe longitudinal distance between vehicles. In connection with these factors, this work deals with the solution of this issue in neighbouring countries through statutory measures, then with statistical analysis of traffic accidents in the Czech Republic caused by non-observance of the safe distance, also problems of assistance systems operating in this area, and subsequently, based on the findings, there are recommended suggestions of actions to increase safety in this area of road transport.
Detection of head biomechanical response during extreme loading
Fanta, Ondřej ; Jelen, Karel (advisor) ; Kovanda, Jan (referee) ; Hynčík, Luděk (referee)
CHARLES UNIVERSITY IN PRAGUE Faculty of Physical Education and Sport Dissertation thesis March 2014 Ondřej Fanta ABSTRACT Title: Detection of head biomechanical response during extreme loading Objectives: The aim of the work was to monitor the current state of knowledge on the issue of closed head injuries, in contact and contactless respectively impacts, to establish appropriate biomechanical indicators for the detection and analysis of internal mechanical response under external mechanical load and to assess the specific circumstances that may affect the resulting injury criteria especially with regard to the actual reaction of the organism before impact. Methods: To the processing research were included and cited in particular impacted world-class publications and bibliography in the number of more than 80sources. The measurements and analysis of contact impacts were taken on the constructed impactor and the analysis of the contactless collisions were taken on the impacts simulator. The monitored biomechanical values were in particularly kinematic data describing the movement of the head towards the neck, values of acceleration of the head, head injury criteria and activity of selected muscles of the neck. Results: It consists diagram of the process of head injury and analysis of two main branches -...
Assessment of shifts of environmental pressure among countires and regions by means of material flow indicators
Maric, Andrija ; Kovanda, Jan (advisor) ; Třebický, Viktor (referee)
World regions are becoming more connected by every day and as a consequence of that dependence rises among states. The states become specialised in production of certain type of the product, services etc. Subsequently they turn to be even more dependent. One does not need to go further back then real-estate crisis in USA that spilled over worldwide. The world is turn out to be "smaller place". America and Europe are exploiting raw material less and less and become dependant on the import of those from around the world. Former exploitation and production became ballast to the environment [environment burdens]. One day factories and mines were closed or reorganised to different production activity and doing so reduced burden to the environment. The consumption of the product remained or was increased even more. In other words, some one else is producing that product. The production shifted among states moving the environment burdens with it. The aim of this document is to provide an overview of impacts relevant to the use of metals zinc, aluminium, nickel, iron and tin; quantification of physical import and export and calculation of international trade balance of before mentioned metals and analysis of six ores. Those aims are supposed to assist us on answering questions to which extent Czech...
Decoupling of environmental pressure and environmental impact from economic performance
Kovalský, Pavel ; Kovanda, Jan (advisor) ; Třebický, Viktor (referee)
7 Abstract The thesis analyses trends of two environmental aspects in spatial terms of the Czech Republic and timal terms since 1993 till 2010. The two aspects are acid deposition as environmental pressure and defoliation of forest crown as environmental impact. Since one aspect is cause of the other the thesis also analyses trends of relationship between these aspects and comapares the results with the concept of decoupling of environmental pressure from economic growth. Important findings are that despite huge relative decrease of environmental pressure expressed by acid deposition the decrease of environmental impact expressed by forest crown defoliation is very low. Although decoupling occured during the analyzed period it's not possible to say that linkage between "environmental bads" and "economic goods" was broken. The thesis reveals factors that had influence on these findings. The thesis also compares particular concepts of decoupling being used and provides author's input on which of these concepts suits the best analyzing the breakage of the links between environmental pressure from economic growth in all of its aspects. Key words: sustainable development, sustainability, decoupling of environmental pressure from economic growth, acid deposition, defoliation, gross domestic product.
Polyzos, Christos ; Kovanda, Jan (advisor) ; Pavlů, Dagmar (referee) ; Rosenberg, Josef (referee)
Introduction: Scoliosis influences the optimal posture and locomotion of the human body. Lumbar and thoraco-lumbar scoliosis has possibly an even greater impact due to the close relation with the pelvic region, a major determinant of gait. The effect of moderate idiopathic scoliosis on the gait cycle of young adults is of major interesting. Discussion-Hypothesis and aims: Young adults (20-40 years old) with MIS (lumbar and thoraco-lumbar primary curves) present kinematic modifications regarding the convex (ipsilateral extremity) or concave (controlateral extremity) side of the body as well as variations compared to non-scoliosis individuals during the gait cycle. Aim of this study was to indentify these variations on the physical quantities exerted from the major joints of the lower extremities as well as the center of gravity too and examine their significance in adult patients with MIS. Materials and methods: A cohort of twenty young adult patients (group A, 12 females- 8 males, mean age 39,7 years) having MIS with mean Cobb's angle 29o (24o to 34o ) and a control group (B) of fifteen (8 females, 7 males) of healthy individuals were submitted in clinical examination and 3-D gait analysis. Direct linear transformation (DLT) was used for analysis of linear displacement on the three axes (x, y and z) as well...
Material flow indicators for the Czech republic: trends, decoupling analysis and uncertainties
Kovanda, Jan ; Moldan, Bedřich (advisor) ; Plesník, Jan (referee) ; Šauer, Petr (referee)
11 Abstract In order for an economic system to function and produce goods and services necessary for meeting human needs, it behaves similarly to a living organism. It absorbs materials from the surrounding environment and transforms them into products, but ultimately all the materials are transformed into some kind of waste and emitted back into the environment. This flow of materials is referred to as industrial or socio-economic metabolism (Baccini and Brunner, 1991; Fischer-Kowalski and Haberl, 1993; Ayres and Simonis, 1994). Extraction of resources, consumption of materials and related emissions exert some pressure on the environment. So far, there has been a positive relation between meeting human needs and this pressure. The overall goal of developed countries within their strategies of sustainable development is to break the relation between pressure exerted on the environment and economic growth, which represents meeting of human needs and improvements in the standard of living. This phenomenon is called decoupling (EC, 2002, 2005, 2006; OECD, 2002; UN, 2002). One of the methods for assessing environmental pressure related to extraction and consumption of resources and materials is material flow analysis. In the case of economy- wide material flow analysis (EW-MFA), this method aims at...
Kinematics and elastokinematics of independent multi-link suspension of axle using flexible supporting elements
Vrána, Tomáš ; Kovanda, Jan (advisor) ; Ladislav, Ladislav (referee)
This thesis deals with elasto-kinematic properties of multi-link rear suspension system, based on simulations. The creation of computational model and simulation of elastokinematics are based on specialized modules of the HyperWorks software. The thesis idea is to create new models and improve their properties. The chapter introduction presents and discusses the current knowledge state in the issue of elasto-kinematic characteristics of the vehicle suspension. Previously published works are presented in this section. The following section defines basic terms, features and design elements concerning the topic vehicle suspension and vehicle axle, which can help readers to orientate in this field. The first part of the thesis is focused on the collection of high-quality input data to create the MBS computational model based on the real suspension components. The determination of kinematic suspension points, experimental measurements of inertia moments of supporting elements of the suspension and measurements of deformation characteristics of rubber-metal bushings are presented in the thesis. There are also measuring characteristics of force elements such as springs or shock absorbers. Then the proposed method of measuring elasto-kinematic characteristics of the suspension using testing machine for model validation is also introduced. The second and main part is devoted to creating a new MBS simulation models of multi-link rear suspension using HyperWorks system. The suspension model is improved by successive steps, from kinematic model, through model with flexibility of the bushings, to the complex model in which the flexible properties of all supporting elements are reflected. The properties of the used models are described together with arising calculation problems. The results discuss the impact of elements flexibility and individual structural alternatives on elasto-kinematic characteristics of the suspension system.

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