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The objective of this research is to propose new routing algorithms for the Storage and Retrieval Mechanism (SRM) in the Cylindrical Automated Storage and Retrieval System (C-AS/RS) and contribute to the system conceptualization by investigating the maximum achievable retrieval request rates for different routing algorithms and system parameters. For this purpose, flexible and detailed simulation model was developed and investigated for 2 SRM types, 3 routing algorithms and a feasible set of system movement and load transfer time parameters. Based on the simulation output, the regression models for different SRM types and routing algorithms were developed for predicting the maximum retrieval request rate. The differences of the average maximum retrieval request rate were evaluated for various system configurations and routing algorithms. The alternative to optimal routing algorithm was proposed, reducing the system performance only by 1.4 ÷ 2.4% on average, but requiring significantly less calculations when planning the SRM tour. In addition, the system analysis indicated that SRM vertical velocity and load transfer time have the highest impact on the system performance and for different SRM types the average maximum retrieval request rates differ by 22.2 ÷ 31.8%. [ABSTRACT FROM PUBLISHER]

The need for the means ensuring passive safety of a vehicle is becoming increasingly emphasized in the area of transport engineering. This area becomes particularly relevant when restoration of the damaged load bearing structures in vehicles is concerned. When performing restoration and modification of the vehicles according to specific needs or repairing them after traffic accidents, the lack of norms giving formalized determination of passive safety and recommendations for its assurance becomes obvious. Computational model of the roof structure developed in LSDYNA is presented, the weld intended for the structure joints is modelled, and residual stresses due to welding process are taken into account, the most effective model of weld location for A-pillar is selected and the influence of A-pillar on the strength of vehicle's roof structure is determined in case of quasi-static compression. [ABSTRACT FROM AUTHOR]

The objective of this research is to propose and investigate a new design of the Cylindrical Automated Storage and Retrieval System (C-AS/RS) and provide a performance comparison of the two types of Storage/Retrieval Mechanisms (SRM I and SRM II) for the system configurations with different input/output location numbers and positions. Although the better performance is expected from of the system with SRM II, because it contains the vertically independent moving load handling devices (LHDs) compared to the interconnected LHDs used in SRM I, the vertically independent movement requires more sophisticated equipment which should be considered by the system designers. Hence, the performance investigation is required to identify the differences between the two types of the SRMs for different C-AS/RS configurations. For this purpose, the detailed simulation model of the C-AS/RS was developed, investigated for various combinations of system parameters and the multiple regression models for predicting system performance measures were developed (adjusted R-square greater than 0.83 for all models). The differences of the performance measures were evaluated and showed that SRM II achieved 7÷20% higher load retrieval rates compared to SRM I for all investigated parameter combinations. The investigation also showed that the number and position of the input/output locations had a significant impact on the system performance. [ABSTRACT FROM AUTHOR]

Despite reduced resistance to wheel rim wear, after every grinding, only geometrical parameters of wheels are restored at maintenance depots. A tendency towards a decrease in the exploitation of wheel rim working edge induces the acquisition of new wheels, is related to a considerable increase in axle load and train speed as well as linked to the ineffective methods of repairing wheel rim working edge. A solution to the problem of restoring the surface of wheelset rolling, as a wider problem of rolling stock durability, is determined by the fact that the breakdown of the rolling wheelset and the loss of its efficiency shortens the service time of the wheelset. The cost of pointless and inefficient renovations of geometrical wheelset parameters increases and is of a very high rate. The problem of efficient renovations to rims and steel used for wheels within the maintenance of wheelsets becomes a burning issue today. [ABSTRACT FROM AUTHOR]

Two fuel kinds of organic origin including rapeseed methyl ester (RME) and ethanol (E) were selected for their different physical-chemical parameters to study the maximum apt volume of oxygenates to mix fossil diesel (D) and establish expectancy to apply D-RME-E blend as a fuel for the unmodified high-speed diesel engine (a combustion chamber consists of a dished piston). The objective of the article is to provide an explicit relationship between the nature of fuel composition and diesel engine operating parameters. The results of the carried out tests on the engine oriented on dynamic and emission characteristics using various portions of the before mentioned bio-components in diesel fuel are presented. Engine behaviour seemed to be improved in the presence of ethanol additives in D-RME blend with a reduction in pollutant emissions in exhaust gases, fuel consumption, ameliorated cetane number, ignition delay time and physical-chemical characteristics of the investigated compounds. The positive and negative aspects of applying bio-based additives in fossil diesel are reported and discussed. [ABSTRACT FROM AUTHOR]

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While investigating collisions with immovable obstacles it is necessary to assess the place of contact, its character and the speed of vehicles before the contact. These parameters depend on the obstacle. The most common cases were analyzed in the article: collision with an immovable obstacle which deformed only a part of the fore of vehicle (collision with a tree, a bollard, etc.); collision with an immovable obstacle which deformed the whole fore of vehicle (collision with a wall, etc.). [ABSTRACT FROM AUTHOR]

Probabilistic methods are based on the use of statistical data about mechanical characteristics and lifetime at cyclic loading of a material. In this investigation statistical low cycle fatigue tests were carried out and mechanical characteristics of three materials (steel of grades 15X2MFA and 45 and aluminium alloy D16T1), representing all possible variations of cyclic properties (fatigue, quasi -- static and intermediate mode of fracture) were determined experimentally. Based on the obtained data the analysis of design curves of equal fracture probability for steels 15X2MFA and 45 and aluminium alloy D16T1 at strain low cycle loading was performed and the design curves were compared with the experimental ones. [ABSTRACT FROM AUTHOR]