Zeitschriften und Ausgaben

Volumen 26 (2019): Heft 4 (December 2019)

Volumen 26 (2019): Heft 3 (September 2019)

Volumen 26 (2019): Heft 2 (June 2019)

Volumen 26 (2019): Heft 1 (March 2019)

Volumen 25 (2018): Heft 4 (December 2018)

Volumen 25 (2018): Heft 3 (September 2018)

Volumen 25 (2018): Heft 2 (June 2018)

Volumen 25 (2018): Heft 1 (March 2018)

Volumen 24 (2017): Heft 4 (December 2017)

Volumen 24 (2017): Heft 3 (September 2017)

Volumen 24 (2017): Heft 2 (June 2017)

Volumen 24 (2017): Heft 1 (March 2017)

Zeitschriftendaten
Format
Zeitschrift
eISSN
2354-0133
Erstveröffentlichung
20 Dec 2019
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

Volumen 26 (2019): Heft 1 (March 2019)

Zeitschriftendaten
Format
Zeitschrift
eISSN
2354-0133
Erstveröffentlichung
20 Dec 2019
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

25 Artikel
Uneingeschränkter Zugang

Gravelling Test for Rail Windshield

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 7 - 15

Zusammenfassung

Abstract

During preliminary tests of locomotive windshield resistance to gravelling, according to the applicable standard PN-EN 15152:2007, carried out in the Institute of Aviation, the problem of the projectile overturning after leaving the cannon barrel was detected. Three tests recorded with a high-speed camera are presented in this article. This problem was found to be due to the incorrect projectile geometry.

In order to stabilise the trajectory of the projectile, four types of projectiles were made using military experience. All of them meet relevant test conditions from the point of view of the test piece (locomotive windshield). The best projectile modification was obtained in the tests with an average deviation of the expected impact angle of 11° compared to 75° for a projectile made exactly according to the guidelines of the standard. Each of 22 modified projectiles hit the test piece with the tip, while out of the 12 original projectiles only 4 hit the test piece with the tip. The impact test results confirm that it is possible to perform a gravelling test according to the standard concept, but it seems necessary to clarify the standard requirements and to modify the projectile shape.

The article contains a proposal for the projectile modification and highlights inaccuracies in the standard concerning the gravelling test.

Schlüsselwörter

  • Impact test
  • locomotive windshield
  • gravelling
  • projectile overturning
  • rail standard
Uneingeschränkter Zugang

Estimation of the Vessel's Sailing Resistance in the Preliminary Analyses

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 17 - 22

Zusammenfassung

Abstract

In this article is presented the methodology of calculation of principal parameters of hull a vessel and resistance components. The approximate method is based on the analysis of the results of model tests and surrender tests presented in the literature. Ship owners' preliminary assumptions for new ship consist of deadweight, speed-shipping line and others. This goal needs definition of principal dimensions of a vessel, which are the basis for further calculations of hull’s resistance and evaluation of necessary power of main engine to fulfil shipping requirements. The route and its environment, type of cargo, quantity to be moved, and value of the cargo and port facilities are typical features, which will be considered when evolving the size, speed, and specification of a suitable ship. Specific service requirements will be similarly considered when evolving vessels such as warships, passenger ships or fishing vessels. Selection of main dimensions of vessel is limited by related to seaways or harbours characteristic and limitations rules regarding buoyancy, stability, hull strength, manoeuvring capability, etc. The influence of the main dimensions of the ship and their coefficients of maritime and strength properties of the ship were presented. Moreover, formulas for calculation of the ship's resistance components, such as friction resistance, and wave shape, as well as the results of calculations for different types of ships, for the assumed deadweight and speed of sailing, are presented.

Schlüsselwörter

  • merchant vessel
  • hull dimensions parameters
  • hull coefficient
  • hull resistance
  • hull power of the vessel
Uneingeschränkter Zugang

PZL-10 Turboshaft Engine–System Design Review

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 23 - 29

Zusammenfassung

Abstract

The PZL – 10-turboshaft gas turbine engine is straight derivative of GTD-10 turboshaft design by OKMB (Omsk Engine Design Bureau). Prototype engine first run take place in 1968. Selected engine is interested platform to modify due gas generator layout 6A+R-2, which is modern. For example axial compressor design from successful Klimov designs TB2-117 (10A-2-2) or TB3-117 (12A-2-2) become obsolete in favour to TB7-117B (5A+R-2-2). In comparison to competitive engines: Klimov TB3-117 (1974 – Mi-14/17/24), General Electric T-700 (1970 – UH60/AH64), Turbomeca Makila (1976 – II225M) the PZL-10 engine design is limited by asymmetric power turbine design layout. This layout is common to early turboshaft design such as Soloview D-25V (Mil-6 power plant). Presented article review base engine configuration (6A+R+2+1). Proposed modifications are divided into different variants in terms of design complexity. Simplest variant is limited to increase turbine inlet temperature (TIT) by safe margin. Advanced configuration replace engine layout to 5A+R+2-2 and increase engine compressor pressure ratio to 9.4:1. Upgraded configuration after modification offers increase of generated power by 28% and SFC reduction by 9% – validated by gas turbine performance model. Design proposal corresponds to a major trend of increasing available power for helicopter engines – Mi-8T to Mi-8MT – 46%, H225M – Makila 1A to 1A2 — 9%), Makila 1A2 to Makila 2-25%.

Schlüsselwörter

  • gas turbine
  • design
  • topology
  • turbo shaft
  • performance
Uneingeschränkter Zugang

Calculation Reliability of Natural Vibrations of Ship Hull and Superstructure

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 31 - 38

Zusammenfassung

Abstract

The ship hull vibration has a great impact on the performance, safety of the devices, structures, and the sailor's comfort when working on the ship. With increases in ship sizes and speeds, shipboard vibration becomes a significant concern in the design and construction of ships. Therefore, designing a ship without any excessive vibration is an important issue and should be studied through analysis right in the design phase. To ensure minimum vibration in a proposed new design; avoid damage to structures, machinery or equipment (mechanically suitable); meeting the requirements of the crew's living environment and working conditions. The ship's natural vibrations are determined to right from the design stage, which will help ship designers and structures avoid dangerous resonance areas. In this study, a three-dimensional finite element model representing the entire ship hull, including the deckhouse and machinery propulsion system, has been developed using numerical modelling implemented in Patran-Nastran software for local and global vibration analyses of the container ship 2000 TEU. Vibration analyses have been conducted under two conditions: free–free (dry) and in-water (wet). The wet analysis has been implemented using Mfluid elements in Nastran software. Because of the global ship free vibration analysis, global natural frequencies and mode shapes have been determined. Combined with the frequency of the main engine and the propeller, the resonant regions with higher frequencies are determined by the resonant graph of the hull. The application of the finite element method for ship vibration analysis shows the optimal of numerical modelling method compared to other traditional methods. This will help other technical problems to be solved with the support of the finite element method.

Schlüsselwörter

  • Finite element method
  • Ship hull vibrations
  • Modal Analysis
  • Patran-Nastran software
Uneingeschränkter Zugang

Nonhomogeneous Poisson Process and Compound Poisson Process in the Modelling of Random Processes Related to Road Accidents

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 39 - 46

Zusammenfassung

Abstract

The stochastic processes theory provides concepts and theorems that allow building probabilistic models concerning accidents. So called counting process can be applied for modelling the number of the road, sea and railway accidents in the given time intervals. A crucial role in construction of the models plays a Poisson process and its generalizations. The new theoretical results regarding compound Poisson process are presented in the paper. A nonhomogeneous Poisson process and the corresponding nonhomogeneous compound Poisson process are applied for modelling the road accidents number and number of injured and killed people in the Polish road. To estimate model parameters were used data coming from the annual reports of the Polish police [9, 10]. Constructed models allowed anticipating number of accidents at any time interval with a length of h and the accident consequences. We obtained the expected value of fatalities or injured and the corresponding standard deviation in the given time interval. The statistical distribution of fatalities number in a single accident and statistical distribution of injured people number and also probability distribution of fatalities or injured number in a single accident are computed. It seems that the presented examples explain basic concepts and results discussed in the paper.

Schlüsselwörter

  • road accident
  • nonhomogeneous Poisson process
  • nonhomogeneous compound Poisson process
Uneingeschränkter Zugang

Wavelet Transform in Vibroacoustic Diagnostic of Machines

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 47 - 55

Zusammenfassung

Abstract

This article discusses the use of wavelet decomposition in the diagnostics of vibrometric signals of an engine. Apart from presenting the possibility of using wavelets in diagnostics, the authors take up the subject of the applicability range of processing for stationary signals, which until now has been reserved for non-stationary signals. A unified definition of signal stationarity has been proposed, which is not based on statistics. The authors presented methods of wavelet decomposition of a vibrometric signal of combustion engine vibrations, measured with the use of LDV (Laser Doppler Vibrometry). Laser measurements allows for studying an object without ‘touching’ its housing. Basing on the relative velocity of engine vibrations, the authors indicate how reliable vibrations are in diagnostics. Despite higher costs, this measurement method gives better results (for specific cases) than acoustic studies. Transform – wavelet decomposition is a solution hardly ever used in machine diagnostics; it is more often applied in medicine and image recognition. The authors presented the differences that can be obtained for different levels of decomposition, and also presented the impact on the engine condition assessment through the use of filtering (windowing) the signal before decomposition.

Schlüsselwörter

  • DSP
  • wavelet
  • LDV
  • combustion engine
Uneingeschränkter Zugang

Thrust Control Systems of Propulsion and their Verification on Dynamically Positioned Vessels

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 57 - 64

Zusammenfassung

Abstract

Thrust vector control systems of propulsion systems of dynamic positioning vessels are commonly applied on vessels with DP2 and DP3 class of DP. It was submitted the ways of providing information to dynamic positioning operator DPO about detecting of suspicion of failure in specific thruster and shown the ways of response in such situations. In the case of failure and shut down one of working thrusters, it must be done the possibility assessment of continuation of DP system safe operation. If such situation is not possible, it should be considered the work of DP system on limitations. It was indicated on safety threats during operation of DP systems resulting from system failure or even the design faults. It commonly applies the failure mode and effect analysis (FMEA or FMECA) from the design phase through sea trials until to the verification process during operation. It allows the elimination of majority of faults in the DP systems. It was communicated the basic conditions of safe operation of vessels with DP systems and the examples of conditions which releasing the readiness signal of DP propulsion system elements. Observed development of control and automatics systems will result in increasing the safety of DP systems operation.

Schlüsselwörter

  • vessel
  • thrust
  • thrust control
  • DP system
Uneingeschränkter Zugang

Integrated Supervision for Supporting Control and Proactive Maintenance of Material Handling System

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 65 - 72

Zusammenfassung

Abstract

Material handling systems, as an important part of different type of manufacturing processes, face the same challenges as manufacturing industries pushed nowadays forward by innovative ideas and technologies to the next level loudly announced as industry 4.0. Development of the next generation of automated manufacturing systems involves advanced approaches to material handling systems design and their close integration with the higher levels of manufacturing and production control and management, e.g. manufacturing execution systems (MES), enterprise resource planning (ERP). In the presence of increasing demands for manufacturing process optimization, the role of supervisory level of material handling systems is much more advanced today, ensuring not only data acquisition, visualization, monitoring, supervisory control, as well as synchronization with the higher control levels (FEM, ERP), but also providing functionality for supporting maintenance and decision-making processes to reduce downtimes, operations and maintenance costs. The article deals with the integration of control and maintenance functions in the hierarchical control system of a crane. The supervisory system for supporting control and proactive maintenance is prototyped at the laboratory overhead travelling crane. The article presents the control-measurement equipment and intelligent software tools implemented in the supervisory control and data acquisition (SCADA) system to aid decision-making process in proactive maintenance. The overview of the main components of the supervisory control and proactive maintenance subsystems is provided, and their respective role in control, supervision, and proactive maintenance is explained. The crane’s supervisory control includes the stereovision-based subsystem applied to identify the crane’s transportation workspace, determine the safety and time-optimal point-to-point trajectory of a payload. The proactive maintenance module consists of the human machine interface (HMI) supporting decision-making process, intelligent tools for upcoming downtime/failure prediction, and the crane's girder inspection using the metal magnetic memory technique.

Schlüsselwörter

  • material handling
  • overhead crane
  • hierarchical control
  • proactive maintenance
Uneingeschränkter Zugang

A Study of Reduction for Combustion Products of a Gasoline Engine – Especially Effects of Multi Component Fuel Properties

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 73 - 79

Zusammenfassung

Abstract

It is well known that the component proportion of gasoline varies depending on the extraction time of crude oil and the production country. Of course, there are effects of the engine performance and the emission on a little. So it is necessary to examine the effects of multi component fuel on the combustion characteristics and emissions. This study aims to examine the effects of fuel composition on the fuel properties and emission characteristics (HC, CO, NOx, etc.) by using multi component fuels in a small gasoline engine. Multi component fuels (model fuel) mixed with plural hydrocarbon compounds was used as fuel. The two kinds of main component fuel were used for the test base fuel (50 vol% Iso-Octane and 25-vol% Toluene). The other addition fuels were selected pure fuel (10 kinds of fuel: Iso-Octane, Toluene, Pentane, Hexane, Heptane, Octane, Di-Isobutylene, Methyl cyclohexane, P-Xylene, Ethanol), it was mixed 25 -vol% in the base fuel. The main conclusions are as follows, 1) The HC emissions decrease with increasing the evaporation velocity of addition fuels for normal chain paraffin. 2) The CO emissions monotonically decrease with increasing excess air ratio by using multi component fuels. 3) It is possible to control the HC, CO and NOx emissions by using the fuel of 25-vol% ethanol addition for a small gasoline engine.

Schlüsselwörter

  • combustion products
  • gasoline engine
  • multi component fuel
Uneingeschränkter Zugang

The Influence of Changing of Treatment Condition on Surface Roughness Parameter During Turning Process by Wiper Insert

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 81 - 88

Zusammenfassung

Abstract

One of the greatest problems of modern production techniques is the achievement of an appropriate quality at minimal costs and accompanied by the production efficiency increase. Therefore, while designing the production process. The technology used should have a considerable influence on the durability and reliability of machine parts to be produced. During finish treatment, the final dimensions as well as functional properties are imparted to a given element by application of proper treatment type. The engineer has a range of production techniques to choose for the proper surface layer formation. It is crucial to find a suitable solution which will meet the requirements as well as the work conditions of a given machine part. The article presents the results of influence of change of cutting parameters on surface roughness parameter during turning process of stainless steel. A shaft made of 304L stainless steel was used for the research. The chemical composition of steel was measured by Solaris-ccd plus optical spectrometer. The cutting process was carried out on a universal CDS 6250 BX-1000 centre lathes. Measurement of surface roughness was carried out by T8000 profilometer. The turning process was conducted by a cutting tool with Wiper insert. During the turning, the following machining parameters were used: cutting speed Vc [m/min], feed f [mm/rev], cutting depth ap [mm] and additionally changed nose radius r [mm], and tool cutting edge angle ᵪr [°]. The results of measurements of Ra parameter underwent statistic analysis. The calculations were conducted by Statistica software.

Schlüsselwörter

  • finish turning process
  • surface roughness parameter
  • cutting parameters
  • stainless steel
Uneingeschränkter Zugang

The Profitability of Disposing of Vehicles Fulfilling the Older Euro Standards in Terms of CO2 Emission

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 89 - 94

Zusammenfassung

Abstract

The automotive market is developing very dynamically. In recent years, we can observe activities of automotive concerns in the production of new models of electric, hybrid and hydrogen vehicles, and conventional cars are supplied with increasingly economical and low-emission engines. There are also increasingly stringent standards related to exhaust emissions from the exhaust system. From September 1, 2018, passenger cars have to comply with the Euro 6d-Temp emission standard and be homologated according to the WLTP test procedure including the WLTC driving cycle and emission measurements in road traffic conditions. The exhaust components measured during the test, such as carbon oxides, nitrogen oxides or hydrocarbons, are toxic to living organisms. However, it seems that the most important issue in the long term may be the value of carbon dioxide emissions, the excess of which poses an ecological threat to the entire planet. The production of new vehicles equipped with modern complicated combustion engines, batteries, fuel cells and electronic devices is associated with a very high emission of this greenhouse gas The authors of the following article, based on their own research, sought to estimate the ecological profitability of replacing a used passenger car meeting the Euro-4 emissions standard for a new vehicle bearing in mind the value of carbon dioxide emissions during vehicle production. The analysis was to indicate how intensive the annual operation of the vehicle should be to make it profitable to recycle and replace it with a modern car with lower emissions considering the global sum of carbon dioxide emissions.

Schlüsselwörter

  • CO emission
  • exhaust gasses
  • cars
  • engines
Uneingeschränkter Zugang

Influence of Marine Main Engine Foundations on the Results of Vibration Calculations

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 95 - 101

Zusammenfassung

Abstract

The article presents an influence of foundations of slow-speed main engine body on the results of numerical analysis of the engine dynamic stiffnesses and thermal deformations. The engine body is much stiffer than its foundation pads and ship hull (double bottom) – boundary conditions of the engine. Especially for the high power, marine engines, the correct model of the boundary conditions plays a key role during the analyses. Therefore, modelling method of engine foundation (boundary conditions) of that kind of model is essential during the analyses. During shaft line alignment and crankshaft springing analyses, knowledge of dynamic stiffnesses characteristics and thermal displacements of radial (main) bearings is significant. Those data of marine main engine body are difficult to estimate because of lack of available documentation and complicated shape of the engine and ship hull. The article presents the methodology of the characteristics determination of the marine engine's body as well as the example of computations for a MAN B&W K98MC type engine (power: 40000 kW, revolutions: 94 rpm) mounted on a 3000 TEU (twenty-foot container equivalent unit) container ship (length: 250 m). Numerical analyses were performed with usage of Nastran software based on Finite Element Method. The FEM model of the engine body comprised over 800 thousand degree of freedom.

Schlüsselwörter

  • marine engines
  • shaft line alignment
  • crankshaft springing
  • boundary conditions of propulsion system
Uneingeschränkter Zugang

Subjective Risk Estimation of the Rare Event

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 103 - 110

Zusammenfassung

Abstract

In the safety engineering, the most frequently disadvantage in risk estimation is the lack of data. In such cases, we have to rely on subjective estimations made by persons with practical knowledge in the field of interest, i.e. experts. However, in some realistic situations, they may have uncertainty in the perceiving and evaluation of the problem considered or limited knowledge of the rare events, such as the consequences of the seagoing ship propulsion failures. The probabilistic models of the risk estimation turn out to be insufficient in modelling the subjective uncertainty. The fuzzy methods are viewed to be powerful in dealing with ambiguity and uncertainty that can be used to handle with the subjective estimation. This article addresses the intuitionistic fuzzy method in the subjective estimation of the ship propulsion failure consequences as rare event risk. In the article, a subjective model of the ship propulsion risk is developed as scenarios of the different subsequent consequences of loss of ship propulsion function until a seriously severe accident resulting in loss of seaworthiness. The model proposes an approach combining AHP method and intuitionistic fuzzy method to assess the occurrence probability and severe probability of these rare events based on the expert opinions. In order to show the applicability of the proposed model, a study case of the propulsion risk of the container carrier operating on the North Atlantic lines is conducted.

Schlüsselwörter

  • rare event
  • subjective risk estimation
  • intuitionistic fuzzy set
  • ship propulsion risk
Uneingeschränkter Zugang

Identification of Inability States of Rotating Subsystems of Vehicles and Machines

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 111 - 118

Zusammenfassung

Abstract

One of the most important subsystems of the vehicles and machines operating currently in industry and transportation are the rotating subsystems. During the subsystems operation, due to the forcing factors influence, the technical state of them is changing and the failure can occur. In order to avoid such a situation the technical state should be identified online. To do this the analysis of the subsystems vibrations is performed. The identified technical state should be considered in a context of the ability and different inability states. Therefore, the first step of the diagnostic procedure is the ability and different inability states identification. In the article, it is proposed to accomplish this goal by the vibrations analysis in time domain. The described research started with the vibration signals acquisition using the experimental stand. In this way, the vibration signals for ability and different inability states were obtained. Afterwards, the signals were divided into learning and testing data sets. For each signal from learning data set, several characteristics were calculated, and they selected the most significant among them. Using the selected characteristics, the signals from the testing data set were analysed. Thanks to it, the testing vibrations signals were counted among the signals collected on the rotating subsystem operating in ability or selected inability state. The result of the performed studies and the accuracy of the technical state of the tested system identification can be found at the end of the article.

Schlüsselwörter

  • rotating system
  • technical state
  • inability state
  • ability state
  • vibration signal
  • diagnostics
  • time domain analyse
Uneingeschränkter Zugang

Experimental Investigations of Various Modes of Charging on HCCI Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 119 - 126

Zusammenfassung

Abstract

Homogeneous Charged Compression Ignition technology is most favourable or suitable for Internal Combustion engines for reducing the exhaust emissions and enhances the Thermal efficiency, improve the fuel consumption, and increase the rate of combustion. This article represents the various charging methods on HCCI technology engine; it improves the engine performance and determines the emission characteristics of HCCI technology engine. The homogeneous mixture prepared with different methods. In–cylinder internal homogeneous mixture preparation method applied in this present work. It reduces the exhaust emissions released from the combustion chamber. However, oxides of nitrogen and soot emissions are significantly reduce, because combustion starts at lower temperatures and various points in combustion chamber.

The HCCI technology generates small amount of exhaust emissions and it improves the performance of the engine. In addition, performance and released emissions depends on the quality and quantity of homogeneous mixture.

Schlüsselwörter

  • HCCI technology
  • homogeneous mixture
  • thermal efficiency
  • combustion rate
  • emissions
Uneingeschränkter Zugang

A Comparative Assessment of Operating Characteristics of a Diesel Engine Using 20% Proportion of Different Biodiesel Diesel Blend

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 127 - 140

Zusammenfassung

Abstract

The objective of the present work is to find out the viable substitute fuel for diesel and control of pollutants from compression ignition engines. Therefore, in this present investigation an attempt has been made to study the effect of 20% proportion of five different biodiesel diesel blend in diesel engine. The 20% proportion of biodiesel such as Jatropha, Pongamia, Mahua, Annona and Nerium and 80% of diesel and it is denoted as J20, P20, M20, A20 and N20 are used in the present investigation. The experimental results showed that the brake thermal efficiency of the different biodiesel blend is slightly lower when compared to neat diesel fuel. However, N20 blend, have shown improvement in performance and reduction in exhaust emissions than that of other biodiesel diesel blends. From, the experimental work, it is found that biodiesel can be used up to 20% and 80% of diesel engine without any major modification.

The conducted experiments were conducted on a four cylinder four stroke DI and turbo charged diesel engine using biodiesel blends of waste oil, rapeseed oil, and corn oil with normal diesel. The peak cylinder pressure of the engine running with bio diesel was slightly higher than that of diesel. The experiments were conducted on a four cylinder four stroke diesel engine using bio diesel made from corn oil.

Schlüsselwörter

  • biodiesel diesel blend
  • performance
  • emission
  • diesel engine
Uneingeschränkter Zugang

Distribution of Masses and Presses on Axles and Wheels and Vehicles' Properties

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 141 - 146

Zusammenfassung

Abstract

One of the most important parameters affecting traction properties as well as driving safety, especially with regard to vehicles with special purpose, is the distribution of wheel and axle loads on the ground. This issue should be taken into account during the process of creating new vehicles as well as during the modernization process. In the first case, it is quite simple because the mass distribution is shaped already in the design phase. In the second case, the problem is more complex, because with modernization solutions we enter an already existing structure. Modernization basically assumes improving the performance and capabilities of the vehicle with possibly small changes in its base structure. Thus, it imposes important boundary conditions. The article presents the methodology of measurement and selected results of measurements of mass distribution as well as wheel and axle loads of selected motor vehicles during their advanced modernization (STAR 266 cars to the version STAR 266M2 and Honker 2000 to the version Honker M-AX). Modernizations carried out by Autobox Innovations Ltd. Lim. Par are mainly focused on increasing the traction of vehicles, traffic safety, and driving comfort. Measurements were made at the above-mentioned company.

Schlüsselwörter

  • car
  • mass
  • pressures
  • properties
Uneingeschränkter Zugang

Reducing Pollution Levels Generated by Short Sea Shipping. Use of Bayesian Networks to Analyse the Utilization of Liquefied Natural Gas as an Alternative Fuel

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 147 - 158

Zusammenfassung

Abstract

Pollution adjacent to the continent's shores has increased in the last decades, so it has been necessary to establish an energy policy to improve environmental conditions. One of the proposed solution was the search of alternative fuels to the commonly used in Short Sea Shipping to reduce pollution levels in Europe. Studies and researches show that liquefied natural gas could meet the European Union environmental requirements. Even environmental benefits are important; currently there is not significant number of vessels using it as fuel. Moreover, main target of this article is exposing result of a research in which a methodology to establish the most relevant variables in the decision to implement liquefied natural gas in Short Sea Shipping has been development using data mining. A Bayesian network was constructed because this kind of network allows to get graphically the relationships between variables and to determine posteriori values that quantify their contributions to decision-making. Bayesian model has been done using data from some European countries (European Union, Norway and Iceland) and database was generated by 35 variables classified in 5 categories. Main obtained conclusion in this analysis is that variables of transport and international trade and economy and finance are the most relevant in the decision-making process when implementing liquefied natural gas. Even more, it can be stablish that capacity of liquefied natural gas regasification terminals under construction and modal distribution of water cargo transportation continental as the most decisive variables because they are the root nodes in the obtained network.

Schlüsselwörter

  • Bayesian networks
  • graph theory
  • artificial networks
  • European Union
  • Short Sea Shipping
  • liquefied natural gas
Uneingeschränkter Zugang

Determination of Coefficients of Energy Losses Occurring in a Constant Capacity Pump Working in a Typical Hydrostatic Drive

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 159 - 166

Zusammenfassung

Abstract

In order to assess possibilities of energy saving during hydrostatic drive system operation, should be learned, and described losses occurring in system. Awareness of proportion of energy, volume, pressure, and mechanical losses in elements is essential for improving functionality and quality of hydrostatic drive systems characterized by unquestionable advantages. In systems with too low efficiency there is increase of load, mainly in case of pump load, which can lead to higher risk of failure, necessity of repair or replacement, as well as to shorten service life of system. Coefficients ki, given in subject literature by Paszota, describe relative value of individual losses in element. They make it possible to assess proportions of losses and assess value of energy efficiency (volumetric, pressure, mechanical) resulting from losses occurring at nominal pressure pn of system in which element is used. As a result, thanks to knowledge of coefficients ki of individual losses, it is possible to determine losses and energy efficiency of components operating in hydraulic system as well as efficiency of system with defined structure of motor speed control as function of speed and load coefficient of motor. Knowledge of coefficients of energy losses occurring in system elements (pump, hydraulic motor, conduits, and motor) allows building models of losses and energy efficiency of element working in system and energy efficiency of system as whole composed of elements. Mathematical models of losses and energy efficiency in system must take into account conditions resulting from applied structure of system, from level of nominal pressure, from rotational speed of motor driving pump shaft, from viscosity change of applied hydraulic oil. Article presents method of determining coefficients of axial piston pump used in typical hydrostatic drive system with proportional control. Values that can be assumed for these loss coefficients for other hydraulic pumps are also given.

Schlüsselwörter

  • coefficients of losses
  • energy losses
  • hydrostatic system
  • axial piston pump
Uneingeschränkter Zugang

Health Monitoring in Landing Gears

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 167 - 174

Zusammenfassung

Abstract

Every mechanical construction loses its properties in time due to the usage wear that leads to malfunctions and, in the end, to failure. Widely used method of failure time prediction base on extended laboratory tests where a device is tested against fatigue and wear. This method is well established but is expensive, time-consuming, and costly. Another way of failure prediction is to calculate it using advanced algorithms what is faster and cheaper but less accurate than actual tests. Furthermore, both methods are not optimal due to the principle of operation based on simplified assumptions. In such cases, it is common to make the lifespan of the safety wise devices for example landing gears much less than real in case of fatal failure not covered by the predictions. This can lead to much higher price and maintenance costs of the landing gear. Nowadays the worldwide trend is to monitor the behaviour of the devices in real time and predict failure using actual state. There are several methods of health monitoring, most of them including sensors, acquisition systems and computer software for analysis.

In this article, authors describe possible landing gears health monitoring methods based on authors ’ laboratory experience in sensor appliance and test data analysis. The authors also present their idea of adding health monitoring to existing landing gears where no dedicated infrastructure was initially designed.

Schlüsselwörter

  • health-monitoring
  • landing gear
  • load measurement
  • pressure measurement
  • strain gauges
Uneingeschränkter Zugang

Computational Simulation of Fully Trimmed Flight of a Helicopter in Hover

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 175 - 181

Zusammenfassung

Abstract

In trimmed flight of a helicopter, all the forces and moments, aerodynamic, inertial, and gravitational, are in balance. Keeping the helicopter in trimmed state, needs a precise adjustment of flight controls. The methodology of simulation of a fully trimmed flight of rotorcraft has been developed and applied to simulate hover of a helicopter.

The presented approach is based on a solution of Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. In contrast to typical solutions of such problem, in the newly developed methodology, the flight controls corresponding to the trimmed-flight conditions are also determined based on the solution of URANS equations.

The methodology is based on coupling of several computational models of Computational Fluid Dynamics and Flight Dynamic. The URANS equations are solved in a three-dimensional region surrounding the flying helicopter, using the ANSYS FLUENT code. The approach is truly three-dimensional, with truly modelled geometry and kinematics of main and tail rotor blades. This applies to modelling of blade flapping and lead-lag motion, too.

The trimming procedure uses six independent parameters (i.e. collective and cyclic pitch of main rotor blades, collective pitch of tail rotor blades, pitch, and bank angles of a helicopter) that should be adjusted so as to balance all forces and moments acting on the helicopter.

The detailed description of the developed methodology as well as the results of simulation of trimmed hover of the helicopter was presented.

Schlüsselwörter

  • helicopter flight simulation
  • hover
  • trimmed flight
  • URANS
Uneingeschränkter Zugang

Modelling of Vane and Rotor Blade Rows in Simulations of Gas Turbine Performance

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 183 - 190

Zusammenfassung

Abstract

A method of modelling of nozzle and rotor blade rows of gas turbine dedicated to simulations of gas turbine performance is proposed. The method is applicable especially in early design stage when many of geometric parameters are yet subject to change. The method is based on analytical formulas derived from considerations of flow theory and from cascade experiments. It involves determination of parameters of gas flow on the mean radius of blade rows. The blade row gas exit angle, determined in turbine design point is a basis for determination of details of blade contour behind the throat position. Throat area is then fixed based on required maximum mass flow in critical conditions. Blade leading edge radius is determined based on flow inlet angle to the blade row in the design point. The accuracy of analytical formulas applied for definition of blade contour details for assumed gas exit angle was verified by comparing the results of analytical formulas with CFD simulations for an airfoil cascade. Losses of enthalpy due to non-isentropic gas flow are evaluated using the analytical model of Craig and Cox, based on cascade experiments. Effects of blade cooling flows on losses of total pressure of the gas are determined based on analytical formulas applicable to film cooling with cooling streams blowing from discrete point along blade surface, including leading and trailing edges. The losses of total pressure due to film cooling of blades are incorporated into the Craig and Cox model as additional factor modifying gas flow velocities.

Schlüsselwörter

  • aircraft engines
  • mechanical engineering
  • engine parts
  • simulation and modelling
Uneingeschränkter Zugang

Operational Problems of Ethylene Transport by LPG Gas Carriers

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 191 - 197

Zusammenfassung

Abstract

Ethylene is one of the basic raw materials of the petrochemical industry used for the production of plastics, mainly plastic packaging. The USA is the largest producer of this compound. The enormous increase in demand for Ethylene has been observed in recent years in China as well as in the Middle and Far East. This caused an unprecedented increase in the demand for transport of this cargo by sea. Ethylene carriers for its transport are special construction LPG vessels, having a cascade cycle with Propylene medium (less often the refrigerant R 404 A). They have been designed in such a way as to withstand a working pressure of up to 5.4 bar, and the minimum temperature of the transported load is minus 104°C for fully cooled Ethylene. This cargo is explosive in the mixture with air (within concentrations of 2.75-2.6%) and during heating under elevation pressure. Therefore, it is required to transport Ethylene in with an inert gas, most often Nitrogen. During the operation of LPG carriers carrying Ethylene, processes of aeration, inerting, gassing-up, cooling tanks and a cargo are repeatedly carried out. The most problematic to carry is gassing-up operation, because it is associated with significant amounts of Ethylene loss, this causes large financial losses. In the article, the authors attempted to diagnose the most serious problems during carrying out the most important for cargo loss the cargo handling operations.

Schlüsselwörter

  • gassing-up
  • gas mixing
  • LPG carriers
  • Ethylene
  • Nitrogen
Uneingeschränkter Zugang

Experimental Strength Analysis of Riveted Joints Using Blind Rivets

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 199 - 206

Zusammenfassung

Abstract

This article presents results of experimental investigations of the lap blind riveted joint. The main goal of the work is determination of destructive load of the blind riveted joints. The blind rivets were originally used in the aircraft structures where access to both sides of the riveted structure is impossible. Blind rivets are now commonly used in many branches of industry because of their low cost. Moreover, the riveting process is uncomplicated. There are many publications about analysis of strength of solid rivets in the research literature. However, the strength analysis of the blind rivets was rarely undertaken. There is the research gap in the analysis of both the strength and the load capacity of blind riveted joints. The influence of selected geometrical parameters of the joint on the stress distribution and the destructive force was not widely described in literature. The first part of the work presents a review of standards and publications related to stress and strength analysis of blind riveted joints. The next part of the study describes experimental investigations of joints. The examined specimens were made out of AW 2017 aluminum alloy, cut from 1 [mm] thick sheet. Investigated blind rivets were made out of aluminum alloy. The lap joint with one rivet and the single row five-rivet joint were investigated. Moreover, the different size of hole chamfer were considered. The experimental tests were performed with the use of Zwick-Roell tension machine. The main results of experimental investigations are ultimate shear load diagrams. The influence of both the hole chamfer and the number of rivets on destructive force and shear diagrams of blind riveted joints were in detail analysed. After shear tests, the fractured rivets were magnified in order to explain the failure phenomenon of blind rivets. In the future research works the obtained results will be used in strength analysis of the blind riveted joints using the finite element method.

Schlüsselwörter

  • blind riveted joint
  • experimental investigations
  • shearing test
  • destructive force
  • chamfers
Uneingeschränkter Zugang

An Overview of Different Possibilities to Master the Challenge of Coupling an AE-Sensor to an Object of Interest Partly Using Examples of Previous Investigations

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 207 - 214

Zusammenfassung

Abstract

Acoustic emission analysis is defined as a passive, non-destructive investigation method, which only listens for AE-waves (AEW), generated actively by an object of interest. Therefore, the AEW must have the possibility to propagate from their source to an acoustic emission sensor (AES). By virtue of the piezoelectric effect, the AEW transmitted into electrical signals inside of the AES. During the analysation of these electrical signals we earn–online–information about the object of interest, e.g. the operating characteristic of a machine or the strength of the friction of a tribolocical system. To enable the AEW to propagate into the AES, the sensor has to be fixed suitable onto the object of interest. Hereby has to be strictly respected, that the sensor is fixed in a reproducible mechanical way as well as to ensure that the through-transmission has a weak attenuation (couplant). Standard AES have the shape of a circular cylinder (diameter and height depend on the operation purpose), the AEW pass through one of the frontends into the sensor. The objects of interest can have different geometry of the surface (e.g. plane, cylindrical, unspecific) or temperatures which usually conflicting the operating range of the sensor. Depending on the operational purpose, there are many different couplants to use. This article offers help to master the different connecting challenges within the range of acoustic emission analysis.

Schlüsselwörter

  • Acoustic emission sensor
  • application
  • mounting
  • couplant
  • wave-guide
25 Artikel
Uneingeschränkter Zugang

Gravelling Test for Rail Windshield

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 7 - 15

Zusammenfassung

Abstract

During preliminary tests of locomotive windshield resistance to gravelling, according to the applicable standard PN-EN 15152:2007, carried out in the Institute of Aviation, the problem of the projectile overturning after leaving the cannon barrel was detected. Three tests recorded with a high-speed camera are presented in this article. This problem was found to be due to the incorrect projectile geometry.

In order to stabilise the trajectory of the projectile, four types of projectiles were made using military experience. All of them meet relevant test conditions from the point of view of the test piece (locomotive windshield). The best projectile modification was obtained in the tests with an average deviation of the expected impact angle of 11° compared to 75° for a projectile made exactly according to the guidelines of the standard. Each of 22 modified projectiles hit the test piece with the tip, while out of the 12 original projectiles only 4 hit the test piece with the tip. The impact test results confirm that it is possible to perform a gravelling test according to the standard concept, but it seems necessary to clarify the standard requirements and to modify the projectile shape.

The article contains a proposal for the projectile modification and highlights inaccuracies in the standard concerning the gravelling test.

Schlüsselwörter

  • Impact test
  • locomotive windshield
  • gravelling
  • projectile overturning
  • rail standard
Uneingeschränkter Zugang

Estimation of the Vessel's Sailing Resistance in the Preliminary Analyses

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 17 - 22

Zusammenfassung

Abstract

In this article is presented the methodology of calculation of principal parameters of hull a vessel and resistance components. The approximate method is based on the analysis of the results of model tests and surrender tests presented in the literature. Ship owners' preliminary assumptions for new ship consist of deadweight, speed-shipping line and others. This goal needs definition of principal dimensions of a vessel, which are the basis for further calculations of hull’s resistance and evaluation of necessary power of main engine to fulfil shipping requirements. The route and its environment, type of cargo, quantity to be moved, and value of the cargo and port facilities are typical features, which will be considered when evolving the size, speed, and specification of a suitable ship. Specific service requirements will be similarly considered when evolving vessels such as warships, passenger ships or fishing vessels. Selection of main dimensions of vessel is limited by related to seaways or harbours characteristic and limitations rules regarding buoyancy, stability, hull strength, manoeuvring capability, etc. The influence of the main dimensions of the ship and their coefficients of maritime and strength properties of the ship were presented. Moreover, formulas for calculation of the ship's resistance components, such as friction resistance, and wave shape, as well as the results of calculations for different types of ships, for the assumed deadweight and speed of sailing, are presented.

Schlüsselwörter

  • merchant vessel
  • hull dimensions parameters
  • hull coefficient
  • hull resistance
  • hull power of the vessel
Uneingeschränkter Zugang

PZL-10 Turboshaft Engine–System Design Review

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 23 - 29

Zusammenfassung

Abstract

The PZL – 10-turboshaft gas turbine engine is straight derivative of GTD-10 turboshaft design by OKMB (Omsk Engine Design Bureau). Prototype engine first run take place in 1968. Selected engine is interested platform to modify due gas generator layout 6A+R-2, which is modern. For example axial compressor design from successful Klimov designs TB2-117 (10A-2-2) or TB3-117 (12A-2-2) become obsolete in favour to TB7-117B (5A+R-2-2). In comparison to competitive engines: Klimov TB3-117 (1974 – Mi-14/17/24), General Electric T-700 (1970 – UH60/AH64), Turbomeca Makila (1976 – II225M) the PZL-10 engine design is limited by asymmetric power turbine design layout. This layout is common to early turboshaft design such as Soloview D-25V (Mil-6 power plant). Presented article review base engine configuration (6A+R+2+1). Proposed modifications are divided into different variants in terms of design complexity. Simplest variant is limited to increase turbine inlet temperature (TIT) by safe margin. Advanced configuration replace engine layout to 5A+R+2-2 and increase engine compressor pressure ratio to 9.4:1. Upgraded configuration after modification offers increase of generated power by 28% and SFC reduction by 9% – validated by gas turbine performance model. Design proposal corresponds to a major trend of increasing available power for helicopter engines – Mi-8T to Mi-8MT – 46%, H225M – Makila 1A to 1A2 — 9%), Makila 1A2 to Makila 2-25%.

Schlüsselwörter

  • gas turbine
  • design
  • topology
  • turbo shaft
  • performance
Uneingeschränkter Zugang

Calculation Reliability of Natural Vibrations of Ship Hull and Superstructure

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 31 - 38

Zusammenfassung

Abstract

The ship hull vibration has a great impact on the performance, safety of the devices, structures, and the sailor's comfort when working on the ship. With increases in ship sizes and speeds, shipboard vibration becomes a significant concern in the design and construction of ships. Therefore, designing a ship without any excessive vibration is an important issue and should be studied through analysis right in the design phase. To ensure minimum vibration in a proposed new design; avoid damage to structures, machinery or equipment (mechanically suitable); meeting the requirements of the crew's living environment and working conditions. The ship's natural vibrations are determined to right from the design stage, which will help ship designers and structures avoid dangerous resonance areas. In this study, a three-dimensional finite element model representing the entire ship hull, including the deckhouse and machinery propulsion system, has been developed using numerical modelling implemented in Patran-Nastran software for local and global vibration analyses of the container ship 2000 TEU. Vibration analyses have been conducted under two conditions: free–free (dry) and in-water (wet). The wet analysis has been implemented using Mfluid elements in Nastran software. Because of the global ship free vibration analysis, global natural frequencies and mode shapes have been determined. Combined with the frequency of the main engine and the propeller, the resonant regions with higher frequencies are determined by the resonant graph of the hull. The application of the finite element method for ship vibration analysis shows the optimal of numerical modelling method compared to other traditional methods. This will help other technical problems to be solved with the support of the finite element method.

Schlüsselwörter

  • Finite element method
  • Ship hull vibrations
  • Modal Analysis
  • Patran-Nastran software
Uneingeschränkter Zugang

Nonhomogeneous Poisson Process and Compound Poisson Process in the Modelling of Random Processes Related to Road Accidents

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 39 - 46

Zusammenfassung

Abstract

The stochastic processes theory provides concepts and theorems that allow building probabilistic models concerning accidents. So called counting process can be applied for modelling the number of the road, sea and railway accidents in the given time intervals. A crucial role in construction of the models plays a Poisson process and its generalizations. The new theoretical results regarding compound Poisson process are presented in the paper. A nonhomogeneous Poisson process and the corresponding nonhomogeneous compound Poisson process are applied for modelling the road accidents number and number of injured and killed people in the Polish road. To estimate model parameters were used data coming from the annual reports of the Polish police [9, 10]. Constructed models allowed anticipating number of accidents at any time interval with a length of h and the accident consequences. We obtained the expected value of fatalities or injured and the corresponding standard deviation in the given time interval. The statistical distribution of fatalities number in a single accident and statistical distribution of injured people number and also probability distribution of fatalities or injured number in a single accident are computed. It seems that the presented examples explain basic concepts and results discussed in the paper.

Schlüsselwörter

  • road accident
  • nonhomogeneous Poisson process
  • nonhomogeneous compound Poisson process
Uneingeschränkter Zugang

Wavelet Transform in Vibroacoustic Diagnostic of Machines

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 47 - 55

Zusammenfassung

Abstract

This article discusses the use of wavelet decomposition in the diagnostics of vibrometric signals of an engine. Apart from presenting the possibility of using wavelets in diagnostics, the authors take up the subject of the applicability range of processing for stationary signals, which until now has been reserved for non-stationary signals. A unified definition of signal stationarity has been proposed, which is not based on statistics. The authors presented methods of wavelet decomposition of a vibrometric signal of combustion engine vibrations, measured with the use of LDV (Laser Doppler Vibrometry). Laser measurements allows for studying an object without ‘touching’ its housing. Basing on the relative velocity of engine vibrations, the authors indicate how reliable vibrations are in diagnostics. Despite higher costs, this measurement method gives better results (for specific cases) than acoustic studies. Transform – wavelet decomposition is a solution hardly ever used in machine diagnostics; it is more often applied in medicine and image recognition. The authors presented the differences that can be obtained for different levels of decomposition, and also presented the impact on the engine condition assessment through the use of filtering (windowing) the signal before decomposition.

Schlüsselwörter

  • DSP
  • wavelet
  • LDV
  • combustion engine
Uneingeschränkter Zugang

Thrust Control Systems of Propulsion and their Verification on Dynamically Positioned Vessels

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 57 - 64

Zusammenfassung

Abstract

Thrust vector control systems of propulsion systems of dynamic positioning vessels are commonly applied on vessels with DP2 and DP3 class of DP. It was submitted the ways of providing information to dynamic positioning operator DPO about detecting of suspicion of failure in specific thruster and shown the ways of response in such situations. In the case of failure and shut down one of working thrusters, it must be done the possibility assessment of continuation of DP system safe operation. If such situation is not possible, it should be considered the work of DP system on limitations. It was indicated on safety threats during operation of DP systems resulting from system failure or even the design faults. It commonly applies the failure mode and effect analysis (FMEA or FMECA) from the design phase through sea trials until to the verification process during operation. It allows the elimination of majority of faults in the DP systems. It was communicated the basic conditions of safe operation of vessels with DP systems and the examples of conditions which releasing the readiness signal of DP propulsion system elements. Observed development of control and automatics systems will result in increasing the safety of DP systems operation.

Schlüsselwörter

  • vessel
  • thrust
  • thrust control
  • DP system
Uneingeschränkter Zugang

Integrated Supervision for Supporting Control and Proactive Maintenance of Material Handling System

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 65 - 72

Zusammenfassung

Abstract

Material handling systems, as an important part of different type of manufacturing processes, face the same challenges as manufacturing industries pushed nowadays forward by innovative ideas and technologies to the next level loudly announced as industry 4.0. Development of the next generation of automated manufacturing systems involves advanced approaches to material handling systems design and their close integration with the higher levels of manufacturing and production control and management, e.g. manufacturing execution systems (MES), enterprise resource planning (ERP). In the presence of increasing demands for manufacturing process optimization, the role of supervisory level of material handling systems is much more advanced today, ensuring not only data acquisition, visualization, monitoring, supervisory control, as well as synchronization with the higher control levels (FEM, ERP), but also providing functionality for supporting maintenance and decision-making processes to reduce downtimes, operations and maintenance costs. The article deals with the integration of control and maintenance functions in the hierarchical control system of a crane. The supervisory system for supporting control and proactive maintenance is prototyped at the laboratory overhead travelling crane. The article presents the control-measurement equipment and intelligent software tools implemented in the supervisory control and data acquisition (SCADA) system to aid decision-making process in proactive maintenance. The overview of the main components of the supervisory control and proactive maintenance subsystems is provided, and their respective role in control, supervision, and proactive maintenance is explained. The crane’s supervisory control includes the stereovision-based subsystem applied to identify the crane’s transportation workspace, determine the safety and time-optimal point-to-point trajectory of a payload. The proactive maintenance module consists of the human machine interface (HMI) supporting decision-making process, intelligent tools for upcoming downtime/failure prediction, and the crane's girder inspection using the metal magnetic memory technique.

Schlüsselwörter

  • material handling
  • overhead crane
  • hierarchical control
  • proactive maintenance
Uneingeschränkter Zugang

A Study of Reduction for Combustion Products of a Gasoline Engine – Especially Effects of Multi Component Fuel Properties

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 73 - 79

Zusammenfassung

Abstract

It is well known that the component proportion of gasoline varies depending on the extraction time of crude oil and the production country. Of course, there are effects of the engine performance and the emission on a little. So it is necessary to examine the effects of multi component fuel on the combustion characteristics and emissions. This study aims to examine the effects of fuel composition on the fuel properties and emission characteristics (HC, CO, NOx, etc.) by using multi component fuels in a small gasoline engine. Multi component fuels (model fuel) mixed with plural hydrocarbon compounds was used as fuel. The two kinds of main component fuel were used for the test base fuel (50 vol% Iso-Octane and 25-vol% Toluene). The other addition fuels were selected pure fuel (10 kinds of fuel: Iso-Octane, Toluene, Pentane, Hexane, Heptane, Octane, Di-Isobutylene, Methyl cyclohexane, P-Xylene, Ethanol), it was mixed 25 -vol% in the base fuel. The main conclusions are as follows, 1) The HC emissions decrease with increasing the evaporation velocity of addition fuels for normal chain paraffin. 2) The CO emissions monotonically decrease with increasing excess air ratio by using multi component fuels. 3) It is possible to control the HC, CO and NOx emissions by using the fuel of 25-vol% ethanol addition for a small gasoline engine.

Schlüsselwörter

  • combustion products
  • gasoline engine
  • multi component fuel
Uneingeschränkter Zugang

The Influence of Changing of Treatment Condition on Surface Roughness Parameter During Turning Process by Wiper Insert

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 81 - 88

Zusammenfassung

Abstract

One of the greatest problems of modern production techniques is the achievement of an appropriate quality at minimal costs and accompanied by the production efficiency increase. Therefore, while designing the production process. The technology used should have a considerable influence on the durability and reliability of machine parts to be produced. During finish treatment, the final dimensions as well as functional properties are imparted to a given element by application of proper treatment type. The engineer has a range of production techniques to choose for the proper surface layer formation. It is crucial to find a suitable solution which will meet the requirements as well as the work conditions of a given machine part. The article presents the results of influence of change of cutting parameters on surface roughness parameter during turning process of stainless steel. A shaft made of 304L stainless steel was used for the research. The chemical composition of steel was measured by Solaris-ccd plus optical spectrometer. The cutting process was carried out on a universal CDS 6250 BX-1000 centre lathes. Measurement of surface roughness was carried out by T8000 profilometer. The turning process was conducted by a cutting tool with Wiper insert. During the turning, the following machining parameters were used: cutting speed Vc [m/min], feed f [mm/rev], cutting depth ap [mm] and additionally changed nose radius r [mm], and tool cutting edge angle ᵪr [°]. The results of measurements of Ra parameter underwent statistic analysis. The calculations were conducted by Statistica software.

Schlüsselwörter

  • finish turning process
  • surface roughness parameter
  • cutting parameters
  • stainless steel
Uneingeschränkter Zugang

The Profitability of Disposing of Vehicles Fulfilling the Older Euro Standards in Terms of CO2 Emission

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 89 - 94

Zusammenfassung

Abstract

The automotive market is developing very dynamically. In recent years, we can observe activities of automotive concerns in the production of new models of electric, hybrid and hydrogen vehicles, and conventional cars are supplied with increasingly economical and low-emission engines. There are also increasingly stringent standards related to exhaust emissions from the exhaust system. From September 1, 2018, passenger cars have to comply with the Euro 6d-Temp emission standard and be homologated according to the WLTP test procedure including the WLTC driving cycle and emission measurements in road traffic conditions. The exhaust components measured during the test, such as carbon oxides, nitrogen oxides or hydrocarbons, are toxic to living organisms. However, it seems that the most important issue in the long term may be the value of carbon dioxide emissions, the excess of which poses an ecological threat to the entire planet. The production of new vehicles equipped with modern complicated combustion engines, batteries, fuel cells and electronic devices is associated with a very high emission of this greenhouse gas The authors of the following article, based on their own research, sought to estimate the ecological profitability of replacing a used passenger car meeting the Euro-4 emissions standard for a new vehicle bearing in mind the value of carbon dioxide emissions during vehicle production. The analysis was to indicate how intensive the annual operation of the vehicle should be to make it profitable to recycle and replace it with a modern car with lower emissions considering the global sum of carbon dioxide emissions.

Schlüsselwörter

  • CO emission
  • exhaust gasses
  • cars
  • engines
Uneingeschränkter Zugang

Influence of Marine Main Engine Foundations on the Results of Vibration Calculations

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 95 - 101

Zusammenfassung

Abstract

The article presents an influence of foundations of slow-speed main engine body on the results of numerical analysis of the engine dynamic stiffnesses and thermal deformations. The engine body is much stiffer than its foundation pads and ship hull (double bottom) – boundary conditions of the engine. Especially for the high power, marine engines, the correct model of the boundary conditions plays a key role during the analyses. Therefore, modelling method of engine foundation (boundary conditions) of that kind of model is essential during the analyses. During shaft line alignment and crankshaft springing analyses, knowledge of dynamic stiffnesses characteristics and thermal displacements of radial (main) bearings is significant. Those data of marine main engine body are difficult to estimate because of lack of available documentation and complicated shape of the engine and ship hull. The article presents the methodology of the characteristics determination of the marine engine's body as well as the example of computations for a MAN B&W K98MC type engine (power: 40000 kW, revolutions: 94 rpm) mounted on a 3000 TEU (twenty-foot container equivalent unit) container ship (length: 250 m). Numerical analyses were performed with usage of Nastran software based on Finite Element Method. The FEM model of the engine body comprised over 800 thousand degree of freedom.

Schlüsselwörter

  • marine engines
  • shaft line alignment
  • crankshaft springing
  • boundary conditions of propulsion system
Uneingeschränkter Zugang

Subjective Risk Estimation of the Rare Event

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 103 - 110

Zusammenfassung

Abstract

In the safety engineering, the most frequently disadvantage in risk estimation is the lack of data. In such cases, we have to rely on subjective estimations made by persons with practical knowledge in the field of interest, i.e. experts. However, in some realistic situations, they may have uncertainty in the perceiving and evaluation of the problem considered or limited knowledge of the rare events, such as the consequences of the seagoing ship propulsion failures. The probabilistic models of the risk estimation turn out to be insufficient in modelling the subjective uncertainty. The fuzzy methods are viewed to be powerful in dealing with ambiguity and uncertainty that can be used to handle with the subjective estimation. This article addresses the intuitionistic fuzzy method in the subjective estimation of the ship propulsion failure consequences as rare event risk. In the article, a subjective model of the ship propulsion risk is developed as scenarios of the different subsequent consequences of loss of ship propulsion function until a seriously severe accident resulting in loss of seaworthiness. The model proposes an approach combining AHP method and intuitionistic fuzzy method to assess the occurrence probability and severe probability of these rare events based on the expert opinions. In order to show the applicability of the proposed model, a study case of the propulsion risk of the container carrier operating on the North Atlantic lines is conducted.

Schlüsselwörter

  • rare event
  • subjective risk estimation
  • intuitionistic fuzzy set
  • ship propulsion risk
Uneingeschränkter Zugang

Identification of Inability States of Rotating Subsystems of Vehicles and Machines

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 111 - 118

Zusammenfassung

Abstract

One of the most important subsystems of the vehicles and machines operating currently in industry and transportation are the rotating subsystems. During the subsystems operation, due to the forcing factors influence, the technical state of them is changing and the failure can occur. In order to avoid such a situation the technical state should be identified online. To do this the analysis of the subsystems vibrations is performed. The identified technical state should be considered in a context of the ability and different inability states. Therefore, the first step of the diagnostic procedure is the ability and different inability states identification. In the article, it is proposed to accomplish this goal by the vibrations analysis in time domain. The described research started with the vibration signals acquisition using the experimental stand. In this way, the vibration signals for ability and different inability states were obtained. Afterwards, the signals were divided into learning and testing data sets. For each signal from learning data set, several characteristics were calculated, and they selected the most significant among them. Using the selected characteristics, the signals from the testing data set were analysed. Thanks to it, the testing vibrations signals were counted among the signals collected on the rotating subsystem operating in ability or selected inability state. The result of the performed studies and the accuracy of the technical state of the tested system identification can be found at the end of the article.

Schlüsselwörter

  • rotating system
  • technical state
  • inability state
  • ability state
  • vibration signal
  • diagnostics
  • time domain analyse
Uneingeschränkter Zugang

Experimental Investigations of Various Modes of Charging on HCCI Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 119 - 126

Zusammenfassung

Abstract

Homogeneous Charged Compression Ignition technology is most favourable or suitable for Internal Combustion engines for reducing the exhaust emissions and enhances the Thermal efficiency, improve the fuel consumption, and increase the rate of combustion. This article represents the various charging methods on HCCI technology engine; it improves the engine performance and determines the emission characteristics of HCCI technology engine. The homogeneous mixture prepared with different methods. In–cylinder internal homogeneous mixture preparation method applied in this present work. It reduces the exhaust emissions released from the combustion chamber. However, oxides of nitrogen and soot emissions are significantly reduce, because combustion starts at lower temperatures and various points in combustion chamber.

The HCCI technology generates small amount of exhaust emissions and it improves the performance of the engine. In addition, performance and released emissions depends on the quality and quantity of homogeneous mixture.

Schlüsselwörter

  • HCCI technology
  • homogeneous mixture
  • thermal efficiency
  • combustion rate
  • emissions
Uneingeschränkter Zugang

A Comparative Assessment of Operating Characteristics of a Diesel Engine Using 20% Proportion of Different Biodiesel Diesel Blend

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 127 - 140

Zusammenfassung

Abstract

The objective of the present work is to find out the viable substitute fuel for diesel and control of pollutants from compression ignition engines. Therefore, in this present investigation an attempt has been made to study the effect of 20% proportion of five different biodiesel diesel blend in diesel engine. The 20% proportion of biodiesel such as Jatropha, Pongamia, Mahua, Annona and Nerium and 80% of diesel and it is denoted as J20, P20, M20, A20 and N20 are used in the present investigation. The experimental results showed that the brake thermal efficiency of the different biodiesel blend is slightly lower when compared to neat diesel fuel. However, N20 blend, have shown improvement in performance and reduction in exhaust emissions than that of other biodiesel diesel blends. From, the experimental work, it is found that biodiesel can be used up to 20% and 80% of diesel engine without any major modification.

The conducted experiments were conducted on a four cylinder four stroke DI and turbo charged diesel engine using biodiesel blends of waste oil, rapeseed oil, and corn oil with normal diesel. The peak cylinder pressure of the engine running with bio diesel was slightly higher than that of diesel. The experiments were conducted on a four cylinder four stroke diesel engine using bio diesel made from corn oil.

Schlüsselwörter

  • biodiesel diesel blend
  • performance
  • emission
  • diesel engine
Uneingeschränkter Zugang

Distribution of Masses and Presses on Axles and Wheels and Vehicles' Properties

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 141 - 146

Zusammenfassung

Abstract

One of the most important parameters affecting traction properties as well as driving safety, especially with regard to vehicles with special purpose, is the distribution of wheel and axle loads on the ground. This issue should be taken into account during the process of creating new vehicles as well as during the modernization process. In the first case, it is quite simple because the mass distribution is shaped already in the design phase. In the second case, the problem is more complex, because with modernization solutions we enter an already existing structure. Modernization basically assumes improving the performance and capabilities of the vehicle with possibly small changes in its base structure. Thus, it imposes important boundary conditions. The article presents the methodology of measurement and selected results of measurements of mass distribution as well as wheel and axle loads of selected motor vehicles during their advanced modernization (STAR 266 cars to the version STAR 266M2 and Honker 2000 to the version Honker M-AX). Modernizations carried out by Autobox Innovations Ltd. Lim. Par are mainly focused on increasing the traction of vehicles, traffic safety, and driving comfort. Measurements were made at the above-mentioned company.

Schlüsselwörter

  • car
  • mass
  • pressures
  • properties
Uneingeschränkter Zugang

Reducing Pollution Levels Generated by Short Sea Shipping. Use of Bayesian Networks to Analyse the Utilization of Liquefied Natural Gas as an Alternative Fuel

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 147 - 158

Zusammenfassung

Abstract

Pollution adjacent to the continent's shores has increased in the last decades, so it has been necessary to establish an energy policy to improve environmental conditions. One of the proposed solution was the search of alternative fuels to the commonly used in Short Sea Shipping to reduce pollution levels in Europe. Studies and researches show that liquefied natural gas could meet the European Union environmental requirements. Even environmental benefits are important; currently there is not significant number of vessels using it as fuel. Moreover, main target of this article is exposing result of a research in which a methodology to establish the most relevant variables in the decision to implement liquefied natural gas in Short Sea Shipping has been development using data mining. A Bayesian network was constructed because this kind of network allows to get graphically the relationships between variables and to determine posteriori values that quantify their contributions to decision-making. Bayesian model has been done using data from some European countries (European Union, Norway and Iceland) and database was generated by 35 variables classified in 5 categories. Main obtained conclusion in this analysis is that variables of transport and international trade and economy and finance are the most relevant in the decision-making process when implementing liquefied natural gas. Even more, it can be stablish that capacity of liquefied natural gas regasification terminals under construction and modal distribution of water cargo transportation continental as the most decisive variables because they are the root nodes in the obtained network.

Schlüsselwörter

  • Bayesian networks
  • graph theory
  • artificial networks
  • European Union
  • Short Sea Shipping
  • liquefied natural gas
Uneingeschränkter Zugang

Determination of Coefficients of Energy Losses Occurring in a Constant Capacity Pump Working in a Typical Hydrostatic Drive

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 159 - 166

Zusammenfassung

Abstract

In order to assess possibilities of energy saving during hydrostatic drive system operation, should be learned, and described losses occurring in system. Awareness of proportion of energy, volume, pressure, and mechanical losses in elements is essential for improving functionality and quality of hydrostatic drive systems characterized by unquestionable advantages. In systems with too low efficiency there is increase of load, mainly in case of pump load, which can lead to higher risk of failure, necessity of repair or replacement, as well as to shorten service life of system. Coefficients ki, given in subject literature by Paszota, describe relative value of individual losses in element. They make it possible to assess proportions of losses and assess value of energy efficiency (volumetric, pressure, mechanical) resulting from losses occurring at nominal pressure pn of system in which element is used. As a result, thanks to knowledge of coefficients ki of individual losses, it is possible to determine losses and energy efficiency of components operating in hydraulic system as well as efficiency of system with defined structure of motor speed control as function of speed and load coefficient of motor. Knowledge of coefficients of energy losses occurring in system elements (pump, hydraulic motor, conduits, and motor) allows building models of losses and energy efficiency of element working in system and energy efficiency of system as whole composed of elements. Mathematical models of losses and energy efficiency in system must take into account conditions resulting from applied structure of system, from level of nominal pressure, from rotational speed of motor driving pump shaft, from viscosity change of applied hydraulic oil. Article presents method of determining coefficients of axial piston pump used in typical hydrostatic drive system with proportional control. Values that can be assumed for these loss coefficients for other hydraulic pumps are also given.

Schlüsselwörter

  • coefficients of losses
  • energy losses
  • hydrostatic system
  • axial piston pump
Uneingeschränkter Zugang

Health Monitoring in Landing Gears

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 167 - 174

Zusammenfassung

Abstract

Every mechanical construction loses its properties in time due to the usage wear that leads to malfunctions and, in the end, to failure. Widely used method of failure time prediction base on extended laboratory tests where a device is tested against fatigue and wear. This method is well established but is expensive, time-consuming, and costly. Another way of failure prediction is to calculate it using advanced algorithms what is faster and cheaper but less accurate than actual tests. Furthermore, both methods are not optimal due to the principle of operation based on simplified assumptions. In such cases, it is common to make the lifespan of the safety wise devices for example landing gears much less than real in case of fatal failure not covered by the predictions. This can lead to much higher price and maintenance costs of the landing gear. Nowadays the worldwide trend is to monitor the behaviour of the devices in real time and predict failure using actual state. There are several methods of health monitoring, most of them including sensors, acquisition systems and computer software for analysis.

In this article, authors describe possible landing gears health monitoring methods based on authors ’ laboratory experience in sensor appliance and test data analysis. The authors also present their idea of adding health monitoring to existing landing gears where no dedicated infrastructure was initially designed.

Schlüsselwörter

  • health-monitoring
  • landing gear
  • load measurement
  • pressure measurement
  • strain gauges
Uneingeschränkter Zugang

Computational Simulation of Fully Trimmed Flight of a Helicopter in Hover

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 175 - 181

Zusammenfassung

Abstract

In trimmed flight of a helicopter, all the forces and moments, aerodynamic, inertial, and gravitational, are in balance. Keeping the helicopter in trimmed state, needs a precise adjustment of flight controls. The methodology of simulation of a fully trimmed flight of rotorcraft has been developed and applied to simulate hover of a helicopter.

The presented approach is based on a solution of Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. In contrast to typical solutions of such problem, in the newly developed methodology, the flight controls corresponding to the trimmed-flight conditions are also determined based on the solution of URANS equations.

The methodology is based on coupling of several computational models of Computational Fluid Dynamics and Flight Dynamic. The URANS equations are solved in a three-dimensional region surrounding the flying helicopter, using the ANSYS FLUENT code. The approach is truly three-dimensional, with truly modelled geometry and kinematics of main and tail rotor blades. This applies to modelling of blade flapping and lead-lag motion, too.

The trimming procedure uses six independent parameters (i.e. collective and cyclic pitch of main rotor blades, collective pitch of tail rotor blades, pitch, and bank angles of a helicopter) that should be adjusted so as to balance all forces and moments acting on the helicopter.

The detailed description of the developed methodology as well as the results of simulation of trimmed hover of the helicopter was presented.

Schlüsselwörter

  • helicopter flight simulation
  • hover
  • trimmed flight
  • URANS
Uneingeschränkter Zugang

Modelling of Vane and Rotor Blade Rows in Simulations of Gas Turbine Performance

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 183 - 190

Zusammenfassung

Abstract

A method of modelling of nozzle and rotor blade rows of gas turbine dedicated to simulations of gas turbine performance is proposed. The method is applicable especially in early design stage when many of geometric parameters are yet subject to change. The method is based on analytical formulas derived from considerations of flow theory and from cascade experiments. It involves determination of parameters of gas flow on the mean radius of blade rows. The blade row gas exit angle, determined in turbine design point is a basis for determination of details of blade contour behind the throat position. Throat area is then fixed based on required maximum mass flow in critical conditions. Blade leading edge radius is determined based on flow inlet angle to the blade row in the design point. The accuracy of analytical formulas applied for definition of blade contour details for assumed gas exit angle was verified by comparing the results of analytical formulas with CFD simulations for an airfoil cascade. Losses of enthalpy due to non-isentropic gas flow are evaluated using the analytical model of Craig and Cox, based on cascade experiments. Effects of blade cooling flows on losses of total pressure of the gas are determined based on analytical formulas applicable to film cooling with cooling streams blowing from discrete point along blade surface, including leading and trailing edges. The losses of total pressure due to film cooling of blades are incorporated into the Craig and Cox model as additional factor modifying gas flow velocities.

Schlüsselwörter

  • aircraft engines
  • mechanical engineering
  • engine parts
  • simulation and modelling
Uneingeschränkter Zugang

Operational Problems of Ethylene Transport by LPG Gas Carriers

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 191 - 197

Zusammenfassung

Abstract

Ethylene is one of the basic raw materials of the petrochemical industry used for the production of plastics, mainly plastic packaging. The USA is the largest producer of this compound. The enormous increase in demand for Ethylene has been observed in recent years in China as well as in the Middle and Far East. This caused an unprecedented increase in the demand for transport of this cargo by sea. Ethylene carriers for its transport are special construction LPG vessels, having a cascade cycle with Propylene medium (less often the refrigerant R 404 A). They have been designed in such a way as to withstand a working pressure of up to 5.4 bar, and the minimum temperature of the transported load is minus 104°C for fully cooled Ethylene. This cargo is explosive in the mixture with air (within concentrations of 2.75-2.6%) and during heating under elevation pressure. Therefore, it is required to transport Ethylene in with an inert gas, most often Nitrogen. During the operation of LPG carriers carrying Ethylene, processes of aeration, inerting, gassing-up, cooling tanks and a cargo are repeatedly carried out. The most problematic to carry is gassing-up operation, because it is associated with significant amounts of Ethylene loss, this causes large financial losses. In the article, the authors attempted to diagnose the most serious problems during carrying out the most important for cargo loss the cargo handling operations.

Schlüsselwörter

  • gassing-up
  • gas mixing
  • LPG carriers
  • Ethylene
  • Nitrogen
Uneingeschränkter Zugang

Experimental Strength Analysis of Riveted Joints Using Blind Rivets

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 199 - 206

Zusammenfassung

Abstract

This article presents results of experimental investigations of the lap blind riveted joint. The main goal of the work is determination of destructive load of the blind riveted joints. The blind rivets were originally used in the aircraft structures where access to both sides of the riveted structure is impossible. Blind rivets are now commonly used in many branches of industry because of their low cost. Moreover, the riveting process is uncomplicated. There are many publications about analysis of strength of solid rivets in the research literature. However, the strength analysis of the blind rivets was rarely undertaken. There is the research gap in the analysis of both the strength and the load capacity of blind riveted joints. The influence of selected geometrical parameters of the joint on the stress distribution and the destructive force was not widely described in literature. The first part of the work presents a review of standards and publications related to stress and strength analysis of blind riveted joints. The next part of the study describes experimental investigations of joints. The examined specimens were made out of AW 2017 aluminum alloy, cut from 1 [mm] thick sheet. Investigated blind rivets were made out of aluminum alloy. The lap joint with one rivet and the single row five-rivet joint were investigated. Moreover, the different size of hole chamfer were considered. The experimental tests were performed with the use of Zwick-Roell tension machine. The main results of experimental investigations are ultimate shear load diagrams. The influence of both the hole chamfer and the number of rivets on destructive force and shear diagrams of blind riveted joints were in detail analysed. After shear tests, the fractured rivets were magnified in order to explain the failure phenomenon of blind rivets. In the future research works the obtained results will be used in strength analysis of the blind riveted joints using the finite element method.

Schlüsselwörter

  • blind riveted joint
  • experimental investigations
  • shearing test
  • destructive force
  • chamfers
Uneingeschränkter Zugang

An Overview of Different Possibilities to Master the Challenge of Coupling an AE-Sensor to an Object of Interest Partly Using Examples of Previous Investigations

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 207 - 214

Zusammenfassung

Abstract

Acoustic emission analysis is defined as a passive, non-destructive investigation method, which only listens for AE-waves (AEW), generated actively by an object of interest. Therefore, the AEW must have the possibility to propagate from their source to an acoustic emission sensor (AES). By virtue of the piezoelectric effect, the AEW transmitted into electrical signals inside of the AES. During the analysation of these electrical signals we earn–online–information about the object of interest, e.g. the operating characteristic of a machine or the strength of the friction of a tribolocical system. To enable the AEW to propagate into the AES, the sensor has to be fixed suitable onto the object of interest. Hereby has to be strictly respected, that the sensor is fixed in a reproducible mechanical way as well as to ensure that the through-transmission has a weak attenuation (couplant). Standard AES have the shape of a circular cylinder (diameter and height depend on the operation purpose), the AEW pass through one of the frontends into the sensor. The objects of interest can have different geometry of the surface (e.g. plane, cylindrical, unspecific) or temperatures which usually conflicting the operating range of the sensor. Depending on the operational purpose, there are many different couplants to use. This article offers help to master the different connecting challenges within the range of acoustic emission analysis.

Schlüsselwörter

  • Acoustic emission sensor
  • application
  • mounting
  • couplant
  • wave-guide

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