An attempt to reduce the vibration of gearbox with non-parallel shaft axes by modifying the spur gear fixing method

In this paper authors carried out research, while modified gear fixing was used to limit the vibrations of the gearbox with non-parallel shaft axes. For tests modified back-to-back test stand was used. During test gearbox worked without load, with various rotational frequency and value of non-parallelism of shafts axes. Analysis of the obtained results presents that only in some cases the use of modified fixing of gear causes a reduction of the measured vibrations

Dynamic model of a harmonic drive in a toothed gear transmission system

The present paper discusses certain aspects of dynamic modeling of the harmonic drive. In particular, a new original dynamic model of a harmonic drive has been proposed for a power transmission system. The model takes account of nonlinear changes in stiffness, as well as damping. The proposed model of a harmonic drive in the power transmission system is investigated in the Matlab-Simulink environment. Utilization of the identified, developed dynamic model will allow to expand the knowledge about torsional vibration which are present in power transmission systems equipped with harmonic drive as well as it will contribute to a reduction of expenses connected with performing costly experimental tests

Application of the discrete wavelet transform and probabilistic neural networks in IC engine fault diagnostics

Around the world are continued attempts to use the vibroacoustic phenomena for purposes of diagnosis of machine condition. Particularly important becomes non-invasive methods including methods based on vibration and acoustic signals. Vibroacoustic phenomena, which relates to the working of technical objects, includes all necessary information connected with the technical condition. The biggest difficulty is the transformation of registered vibroacoustic signals and creation on their basic measures, which will be non-sensitive to any type of interference occurring during the operation of objects and recording signals. To the group of technical objects, for which are already conducted numerous studies all over the world, connected with use of vibroacoustic phenomena for diagnostic purposes which relates to the automotive drive systems, including combustion engines. Combustion engines during its working generate a whole range of vibroacoustic phenomena bringing information on the proper operation of the engine, as well as on condition of each of its elements. In a combustion engine, there are many sources of vibroacoustic phenomena, which contributes to the disruption of diagnostic information. The development of appropriate methods for vibroacoustic signal processing and complete diagnostic systems may allow future extension of the on-board diagnostics OBD system – currently in used cars. The most interesting would be the development of complex system for diagnosing the condition of the individual elements of the car engine operating by basing on information from vibroacoustic signals. In this article are shown results of research, which aim is to diagnose damages of mechanical elements of car combustion engine using vibration signals and artificial neural networks

The optimization of the ribbing of gear transmission housing used in transportation machines

The present paper discusses results of simulation tests conducted using an identified dynamic model of a laboratory station with gear transmissions. The dynamic forces found to be acting in bearing assemblies were assumed as input functions for the purposes of studies of the numerical housing models developed. Using fine-tuned modal housing models in the analysis of the design solutions applied allowed for choosing appropriate arrangement of the transmission ribbing. By analyzing the shape of the ribbing layout envisaged as well as its structural characteristics (height and width of ribs), one could choose a housing of reduced vibroactivity and mass

Determination of the effect of tire stiffness on wheel accelerations by the forced vibration test method

The paper presents results of a vibroacoustic signal analysis of the unsprung mass in a car actuated by harmonic kinematic vibrations. A passenger car with a hydropneumatic suspension system and standard tires was examined. Different tire pressures were used during the experiments. The authors applied the short time Fourier transform method with superposition of the Hanning windows combined with the zero complement method. With reference to the STFT spectrum, values of the unsprung mass resonance frequency were identified. The results of the experiments described in the publication are particularly useful for the personnel of vehicle service stations, especially that they relate to the effect of tire pressure changes occurring in a vehicle with a hydropneumatic suspension system on the vibration test results

Stark Spectroscopy and Radiative Lifetimes in Single Self-Assembled CdTe Quantum Dots

We present studies on Coulomb interactions in single self-assembled CdTe quantum dots. We use a field effect structure to tune the charge state of the dot and investigate the impact of the charge state on carrier wave functions. The analysis of the quantum confined Stark shifts of four excitonic complexes allows us to conclude that the hole wave function is softer than electron wave function, i. e. it is subject to stronger modifications upon changing of the dot charge state. These conclusions are corroborated by time-resolved photoluminescence studies of recombination lifetimes of different excitonic complexes. We find that the lifetimes are notably shorter than expected for strong confinement and result from a relatively shallow potential in the valence band. This weak confinement facilitates strong hole wave function redistributions. We analyze spectroscopic shifts of the observed excitonic complexes and find the same sequence of transitions for all studied dots. We conclude that the universality of spectroscopic shifts is due to the role of Coulomb correlations stemming from strong configuration mixing in the valence band.Comment: sent to Physical Review

: Final report

63 p.Interest in cities is growing again in Europe. Theories of "growth poles" forgotten since the 1960s re-emerge, although in different form, without the idea of building new cities in the desert. Metropolitanisation, although sometimes difficult to grasp empirically, is recognized as a post-fordist phenomena, with a gain of the importance of large cities, linked to the increasing need for size-based agglomeration effect in the global, networked knowledge economy. And European policy makers are once again discussing the need of and the form for new urban policies at European (as witnessed by the above quote), but also at national scale. From the outset, this project has had two, complementary, but not always easily reconcilable orientations: provide a broad overview of the current and future issues relevant to urban development in all of Europe, advance scientifically beyond the established and well-known data and analyses, provide innovative research. As this report was elaborated in parallel to the new State of European Cities report to be published by DG Regio, we also aimed at complementarity with that report, not wanting to repeat the same analyses based on the same data. In this project, we, therefore, worked in three parallel strands. First, all teams went through the current literature to extract the knowledge about trends, perspectives and, most importantly, driving forces for urban development in their thematic fields. Second, each of the teams focused on one or two innovative empirical research questions, generally tapping new data sources. Finally, our scenario team has taken the work of the other teams, and substantially augmented it through additional literature review, aiming at covering an even larger horizon and to provide a complete knowledge base on urban development, necessary for integrated prospective thinking. On this basis the scenarios were developed. The structure of the report reflects these three strands, adding a fourth, new strand, which consists in an assessment of the current national policy visions on urban issues across Europe. Details of all the literature reviews and analyses are presented in the scientific report

: Final report

63 p.Interest in cities is growing again in Europe. Theories of "growth poles" forgotten since the 1960s re-emerge, although in different form, without the idea of building new cities in the desert. Metropolitanisation, although sometimes difficult to grasp empirically, is recognized as a post-fordist phenomena, with a gain of the importance of large cities, linked to the increasing need for size-based agglomeration effect in the global, networked knowledge economy. And European policy makers are once again discussing the need of and the form for new urban policies at European (as witnessed by the above quote), but also at national scale. From the outset, this project has had two, complementary, but not always easily reconcilable orientations: provide a broad overview of the current and future issues relevant to urban development in all of Europe, advance scientifically beyond the established and well-known data and analyses, provide innovative research. As this report was elaborated in parallel to the new State of European Cities report to be published by DG Regio, we also aimed at complementarity with that report, not wanting to repeat the same analyses based on the same data. In this project, we, therefore, worked in three parallel strands. First, all teams went through the current literature to extract the knowledge about trends, perspectives and, most importantly, driving forces for urban development in their thematic fields. Second, each of the teams focused on one or two innovative empirical research questions, generally tapping new data sources. Finally, our scenario team has taken the work of the other teams, and substantially augmented it through additional literature review, aiming at covering an even larger horizon and to provide a complete knowledge base on urban development, necessary for integrated prospective thinking. On this basis the scenarios were developed. The structure of the report reflects these three strands, adding a fourth, new strand, which consists in an assessment of the current national policy visions on urban issues across Europe. Details of all the literature reviews and analyses are presented in the scientific report

Architektura Miasto Piękno tom 2

"Wydział Architektury Politechniki Krakowskiej zawsze był miejscem pełnym osobowości, indywidualności, talentów. Gdy profesorowie i mistrzowie odchodzili z Wydziału, mieliśmy świadomość, że tu nigdy już nie będzie tak samo. Wydział jednak trwał i trwa jak piękno miasta, które jest przecież dziełem zbiorowym, o nakładających się warstwach, wzmacniających i tworzących jego tożsamość. Tak też kolejne pokolenia kontynuują i budują historię Wydziału. Wydział pełen jest wspomnień i anegdot. W fotografiach, księgach, obrazach, meblach kryją się opowieści."(...