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Special Zeszyt: Coastal, Offshore and Ocean Engineering

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Special Zeszyt: Computing Science and Mechanical Engineering in Marine

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Special Zeszyt Title: Marine Processes Studies and Marine Engineering

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Title: Special issue

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Scientific Seminar in memory of Professor Stefan Perycz

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Informacje o czasopiśmie
Format
Czasopismo
eISSN
2083-7429
Pierwsze wydanie
20 Jul 2007
Częstotliwość wydawania
4 razy w roku
Języki
Angielski

Wyszukiwanie

Tom 22 (2015): Zeszyt 2 (April 2015)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
2083-7429
Pierwsze wydanie
20 Jul 2007
Częstotliwość wydawania
4 razy w roku
Języki
Angielski

Wyszukiwanie

13 Artykułów
Otwarty dostęp

Risk Analysis Of Collision Between Passenger Ferry And Chemical Tanker In The Western Zone Of The Baltic Sea

Data publikacji: 10 Jul 2015
Zakres stron: 3 - 8

Abstrakt

Abstract

This paper presents assumptions and process of the forming of a risk assessment model for collision between a passenger ferry departing from or approaching port of Świnoujście and a chemical tanker carrying a dangerous cargo. In order to assess navigational safety on the basis of data obtained from AIS system, were prepared probabilistic domains of ships, which made it possible to estimate number of navigational incidents as well as their spatial distribution, that consequently allowed to determine potentially dangerous areas. The next phase was formulation of a simulative model intended for the calculating of probability of collision between the ferry and chemical tanker as well as the determining of characteristic scenarios for such collision. This paper presents also an analysis of consequences of the collision with taking into consideration a damage of cargo tanks.

Słowa kluczowe

  • safety of navigation
  • navigational risk
  • ships domain
  • ships collisions
  • simulation methods
Otwarty dostęp

Accuracy Of The GPS Positioning System In The Context Of Increasing The Number Of Satellites In The Constellation

Data publikacji: 10 Jul 2015
Zakres stron: 9 - 14

Abstrakt

Abstract

A possibility of utilising the GPS system for navigation and transport are fundamentally dependent on the accuracy in positioning. Two fundamental factors decisive for its value are the values of the User Range Error (URE) and Dilution of Precision (DOP), strictly related to the number of satellites forming the constellation. The nominal constellation of GPS satellites consists of 24 units which gives a possibility of identification of coordinates all over the globe. In the last few years, however, the nominal number of satellites in the constellation was much higher, and the URE value has been constantly increasing.

The authors of the paper try to estimate the impact of the changing number of GPS satellites on accuracy of position coordinates with a variable URE value. Mathematical model for estimating geometrical indicators’ value, utilising data derived from the almanac files has been presented. Following a drawn-up algorithm and calculations made with Mathcad software, the authors carried out a comparative analysis of mean daily values of DOP indicators for a variable number of satellites included in the GPS constellation in the years 2001-2013. Then, the authors have established representative values of Two Distance Root Mean Square Error (2drms) 2D and 3D, and calculated a percentage increase of accuracy in the period under discussion.

Słowa kluczowe

  • GPS
  • User Range Error
  • Dilution of Precision
  • GPS Almanac
  • Accuracy of Positioning
Otwarty dostęp

A Proposal Of Simulation Model Of A Wind-Steering System For Sailing Yachts, Based On Single-Stage Servo-Pendulum Coupled With Main Rudder

Data publikacji: 10 Jul 2015
Zakres stron: 15 - 22

Abstrakt

Abstract

The aim of this study was to investigate possible application of fast design prototyping methods for wind-steering systems used in offshore sailing yachts. The development of such methods would help to speed up the construction work and reduce the scope of necessary experimental research, prior to implementation of the system. In the present work, based on an analysis of existing designs of windvane systems, a preliminary selection of the system configuration has been undertaken, in terms of a compromise between efficiency, performance, and design complexity. Construction design of a single-stage, servo – pendulum system, has been developed by using the Autodesk Inventor design package. Next, based on the design data, a simulation model of the system, has been produced by using Matlab - Simulink software and SimMechanics library. The model was further verified in terms of kinematics mapping with the use of Matlab visualization tools.

Słowa kluczowe

  • sailing yachts
  • wind-steering system
  • automation
Otwarty dostęp

A Hydrodynamic Methodology And CFD Analysis For Performance Prediction Of Stepped Planing Hulls

Data publikacji: 10 Jul 2015
Zakres stron: 23 - 31

Abstrakt

Abstract

Nowadays all efforts in planing hull research are focused on resistance reduction for achieving the highest speed in fast planing crafts. Furthermore, many fruitful research projects have been carried out on marine coatings, planing equipment, and optimization of propeller and hull form, which revolutionized industry of high - speed crafts and made them an efficient survival vehicle in coastal areas and rivers. In this paper the hydrodynamic performance of planing hulls are investigated by means of a modified Savitsky model for both non-stepped and stepped bodies. Meanwhile, in order to meet this goal reasonably, effective geometrical parameters of planing hull are investigated and then operational hydrodynamic characteristics of the craft are predicted by using a computational program. Finally, the calculation results are verified by means of a CFD-analysis model.

Słowa kluczowe

  • Planing hull
  • Hydrodynamic performance
  • CFD analyzed
Otwarty dostęp

Comparison Of The Powers Of Energy Losses In A Variable Capacity Displacement Pump Determined Without Or With Taking Into Account The Power Of Hydraulic Oil Compression

Data publikacji: 10 Jul 2015
Zakres stron: 32 - 43

Abstrakt

Abstract

Powers of energy losses in a variable capacity displacement pump are compared with or without taking into account the power of hydraulic oil compression. Evaluation of power of liquid compression in the pump was made possible by the use of method, proposed by the Author, of determining the degree of liquid aeration in the pump. In the method of determining the liquid aeration in the pump and of powers of volumetric losses of liquid compression a simplified formula (qPvc × ΔpPi)/2 was used describing the field of indicated work of volumetric losses qPvc of liquid compression during one shaft revolution at indicated increase ΔpPi of pressure in the chambers. Three methods were used for comparing the sum of powers of volumetric losses ΔPPvl due to leakage and ΔPPvc of compression and also ΔPPm|ΔpPi of mechanical losses resulting from increase ΔpPi of indicated pressure in the working chambers.

Słowa kluczowe

  • hydrostatic drive
  • variable capacity displacement pump
  • volumetric losses of hydraulic oil
Otwarty dostęp

Identification Of Damages Of Tribological Associations In Crankshaft And Piston Systems Of Two-Stroke Internal Combustion Engines Used As Main Propulsion In Sea-Going Vessels And Proposal Of Probabilistic Description Of Loads As Causes Of These Damages

Data publikacji: 10 Jul 2015
Zakres stron: 44 - 54

Abstrakt

Abstract

The article discusses damages of essential tribological associations in crankshaft and piston systems of large power two-stroke engines used as main engines, which take place during transport tasks performed by those ships. Difficulties are named which make preventing those damages impossible, despite the fact that the technical state of engines of this type is identified with the aid of complex diagnostic systems making use of advanced computer technology. It is demonstrated that one of causes of the damages is the lack of research activities oriented on recognising random properties of the loads leading to those damages. A proposal is made for the loads acting at a given time t on tribological associations in crankshaft and piston systems of internal combustion engines used as main engines to be considered as random variables Qt. At the same time the loads examined within a given time interval tr ≤ t ≤ tz would be considered stochastic processes {Q(t): t ≥ 0}. Essential properties of the loads of the abovementioned tribological associations are named and explained by formulating hypotheses which need empirical verification. Interval estimation is proposed for estimating the expected value E(Qt) of the load Qt acting at time t. A relation is indicated between the mechanical load and the thermal load acting on tribological associations in the ship main engine crankshaft and piston system. A suggestion is formulated that a stochastic form of the relation between these types of load is to be searched for, rather than statistic relation, and a proposal is made to measure the intensity (strength) of the stochastic relation using the Czuprow’s convergence coefficient.

Słowa kluczowe

  • probability
  • friction associations
  • crankshaft and piston system
  • semi-Markov process
  • marine internal combustion engine
  • wear
Otwarty dostęp

Analysing Applicability Of Selected Methods To Smooth Indicator Diagrams Of Marine Medium-Speed Engine

Data publikacji: 10 Jul 2015
Zakres stron: 55 - 61

Abstrakt

Abstract

The article analyses the applicability of selected smoothing methods to smooth indicator diagram curves and to filter disturbances. An intermediate goal of the study was an attempt to extract disturbances recorded during pressure curve smoothing, which are believed to be a source of important diagnostic information.

Within the framework of the reported analysis, a comparison was made between the moving average method, the Savitzky-Golay filter, and the frequency filtration method. The research was performed on a marine medium-speed engine Sulzer 3Al 25/30, which has a relatively long indicator passage.

Słowa kluczowe

  • indicator diagrams
  • smoothing waveforms
  • filtering disturbances
Otwarty dostęp

Clocking In Turbines: Remarks On Physical Nature And Geometric Requirements

Data publikacji: 10 Jul 2015
Zakres stron: 62 - 70

Abstrakt

Abstract

The article discusses two issues relating to the clocking phenomenon in turbines, which are the physical course of stator wake deformation in rotor passages and its further interaction with downstream stator blades, and turbine geometry parameters which are believed to be most favourable for clocking. In both cases, the results presented in the article have made it possible to verify and reformulate the previously accepted opinions.

Słowa kluczowe

  • turbines
  • clocking
  • wakes
  • vortices
  • blade counts
Otwarty dostęp

Simplified Procedure For The Free Vibration Analysis Of Rectangular Plate Structures With Holes And Stiffeners

Data publikacji: 10 Jul 2015
Zakres stron: 71 - 78

Abstrakt

Abstract

Thin and thick plates, plates with holes, stiffened panels and stiffened panels with holes are primary structural members in almost all fields of engineering: civil, mechanical, aerospace, naval, ocean etc. In this paper, a simple and efficient procedure for the free vibration analysis of such elements is presented. It is based on the assumed mode method and can handle different plate thickness, various shapes and sizes of holes, different framing sizes and types as well as different combinations of boundary conditions. Natural frequencies and modes are determined by solving an eigenvalue problem of a multi-degree-of-freedom system matrix equation derived by using Lagrange’s equations. Mindlin theory is applied for a plate and Timoshenko beam theory for stiffeners. The applicability of the method in the design procedure is illustrated with several numerical examples obtained by the in-house developed code VAPS. Very good agreement with standard commercial finite element software is achieved.

Słowa kluczowe

  • energy approach
  • plate with hole
  • stiffened panel
  • thick plate
  • VAPS software
  • free vibration analysis
Otwarty dostęp

Problems Of Determination Of Welding Angular Distortions Of T - Fillet Joints In Ship Hull Structures

Data publikacji: 10 Jul 2015
Zakres stron: 79 - 85

Abstrakt

Abstract

Ship hull structure elements are usually joined by welding. Welding distortions may cause many problems during manufacturing process. In the literature a wide spectrum of suggestions has been proposed for correct estimation of welding deformation, particularly angular ones, in the fillet welded T-joints. In this work a verification of certain methods selected from the literature is presented basing upon the results of the laboratory measurements. To this end, values determined on the basis of engineering hypotheses have been compared with those obtained from the laboratory tests.

Słowa kluczowe

  • welding deformations
  • ship structure welding
  • angular distortions in welded T-joints
Otwarty dostęp

Selected Aspects Of Building, Operation And Environmental Impact Of Offshore Wind Power Electric Plants

Data publikacji: 10 Jul 2015
Zakres stron: 86 - 92

Abstrakt

Abstract

This paper describes essence of work of offshore wind power electric plants and crucial aspects of their building and operating. Prospects for development of global, European and domestic markets of offshore wind power industry have been delineated. A comparative analysis of environmental impact of an offshore and land-based 2MW wind power electric plant has been performed by using LCA method and Ecoindex – 99 (Ekowskaźnik 99) modelling.

Słowa kluczowe

  • wind energy
  • offshore wind power electric plants
  • LCA method
  • Ekowskaźnik 99 (Ecoindex - 99)
Otwarty dostęp

Mathematical Modelling Of Elastic Deflection Of A Tubular Cross-Section

Data publikacji: 10 Jul 2015
Zakres stron: 93 - 100

Abstrakt

Abstract

Cutting a tubular element into thin rings is an operation often used in engineering processes. Total work of the cutting consists of that necessary for initial deflection of cut material and the cutting work itself. This paper presents mathematical models which describe deflection of cross-section of a single tubular element as well as a single layer of tubes under action of external forces (acting and reacting ones). The deflection concerns end part of tube hence the cutting object model has been reduced to a thin ring. Results of calculation by using the developed models are presented for selected materials of tubular elements, which are commonly used for structures of the kind; moreover, they are prepared in a form of dimensionless diagrams, that makes it possible to use them for an arbitrary material.

Słowa kluczowe

  • mathematical modelling of elastic deflection
  • tubular elements
  • deflection of a ring under action of external forces
Otwarty dostęp

Low Temperature Properties Of Fuel Mixtures Of Kerosene And Fame Type Used To Supply Turbine Engines In Marine And Other Non-Aeronautical Applications

Data publikacji: 10 Jul 2015
Zakres stron: 101 - 105

Abstrakt

Abstract

A worldwide trend to popularise gradually increasing use of biofuels in various applications was a motivation for gaining interest in FAME as a commonly available biocomponent to fuels combusted in turbine engines. These engines are mainly used in aeronautics, but many of them are also used in other, non-aeronautical areas, including marine navigation. Specific conditions in which fuels are combusted in turbine engines used in these applications are the reason why fuel mixtures of kerosene and FAME type should reveal relevant low temperature characteristics. The article presents results of tests of low temperature properties of mixtures of the jet fuel Jet A-1 and methyl esters of higher fatty acids (FAME). The prepared mixtures contained different contents of FAME. The obtained results present changes of: viscosity, cloud point, pour point, crystallising point, and cold filter plugging point, depending on the percentage by volume of FAME. They also prove that the course of changes of low temperature properties of these mixtures is affected by chemical structure of the biocomponent.

Słowa kluczowe

  • jet fuel
  • biocomponents
  • marine turbine engine
  • low temperature properties
13 Artykułów
Otwarty dostęp

Risk Analysis Of Collision Between Passenger Ferry And Chemical Tanker In The Western Zone Of The Baltic Sea

Data publikacji: 10 Jul 2015
Zakres stron: 3 - 8

Abstrakt

Abstract

This paper presents assumptions and process of the forming of a risk assessment model for collision between a passenger ferry departing from or approaching port of Świnoujście and a chemical tanker carrying a dangerous cargo. In order to assess navigational safety on the basis of data obtained from AIS system, were prepared probabilistic domains of ships, which made it possible to estimate number of navigational incidents as well as their spatial distribution, that consequently allowed to determine potentially dangerous areas. The next phase was formulation of a simulative model intended for the calculating of probability of collision between the ferry and chemical tanker as well as the determining of characteristic scenarios for such collision. This paper presents also an analysis of consequences of the collision with taking into consideration a damage of cargo tanks.

Słowa kluczowe

  • safety of navigation
  • navigational risk
  • ships domain
  • ships collisions
  • simulation methods
Otwarty dostęp

Accuracy Of The GPS Positioning System In The Context Of Increasing The Number Of Satellites In The Constellation

Data publikacji: 10 Jul 2015
Zakres stron: 9 - 14

Abstrakt

Abstract

A possibility of utilising the GPS system for navigation and transport are fundamentally dependent on the accuracy in positioning. Two fundamental factors decisive for its value are the values of the User Range Error (URE) and Dilution of Precision (DOP), strictly related to the number of satellites forming the constellation. The nominal constellation of GPS satellites consists of 24 units which gives a possibility of identification of coordinates all over the globe. In the last few years, however, the nominal number of satellites in the constellation was much higher, and the URE value has been constantly increasing.

The authors of the paper try to estimate the impact of the changing number of GPS satellites on accuracy of position coordinates with a variable URE value. Mathematical model for estimating geometrical indicators’ value, utilising data derived from the almanac files has been presented. Following a drawn-up algorithm and calculations made with Mathcad software, the authors carried out a comparative analysis of mean daily values of DOP indicators for a variable number of satellites included in the GPS constellation in the years 2001-2013. Then, the authors have established representative values of Two Distance Root Mean Square Error (2drms) 2D and 3D, and calculated a percentage increase of accuracy in the period under discussion.

Słowa kluczowe

  • GPS
  • User Range Error
  • Dilution of Precision
  • GPS Almanac
  • Accuracy of Positioning
Otwarty dostęp

A Proposal Of Simulation Model Of A Wind-Steering System For Sailing Yachts, Based On Single-Stage Servo-Pendulum Coupled With Main Rudder

Data publikacji: 10 Jul 2015
Zakres stron: 15 - 22

Abstrakt

Abstract

The aim of this study was to investigate possible application of fast design prototyping methods for wind-steering systems used in offshore sailing yachts. The development of such methods would help to speed up the construction work and reduce the scope of necessary experimental research, prior to implementation of the system. In the present work, based on an analysis of existing designs of windvane systems, a preliminary selection of the system configuration has been undertaken, in terms of a compromise between efficiency, performance, and design complexity. Construction design of a single-stage, servo – pendulum system, has been developed by using the Autodesk Inventor design package. Next, based on the design data, a simulation model of the system, has been produced by using Matlab - Simulink software and SimMechanics library. The model was further verified in terms of kinematics mapping with the use of Matlab visualization tools.

Słowa kluczowe

  • sailing yachts
  • wind-steering system
  • automation
Otwarty dostęp

A Hydrodynamic Methodology And CFD Analysis For Performance Prediction Of Stepped Planing Hulls

Data publikacji: 10 Jul 2015
Zakres stron: 23 - 31

Abstrakt

Abstract

Nowadays all efforts in planing hull research are focused on resistance reduction for achieving the highest speed in fast planing crafts. Furthermore, many fruitful research projects have been carried out on marine coatings, planing equipment, and optimization of propeller and hull form, which revolutionized industry of high - speed crafts and made them an efficient survival vehicle in coastal areas and rivers. In this paper the hydrodynamic performance of planing hulls are investigated by means of a modified Savitsky model for both non-stepped and stepped bodies. Meanwhile, in order to meet this goal reasonably, effective geometrical parameters of planing hull are investigated and then operational hydrodynamic characteristics of the craft are predicted by using a computational program. Finally, the calculation results are verified by means of a CFD-analysis model.

Słowa kluczowe

  • Planing hull
  • Hydrodynamic performance
  • CFD analyzed
Otwarty dostęp

Comparison Of The Powers Of Energy Losses In A Variable Capacity Displacement Pump Determined Without Or With Taking Into Account The Power Of Hydraulic Oil Compression

Data publikacji: 10 Jul 2015
Zakres stron: 32 - 43

Abstrakt

Abstract

Powers of energy losses in a variable capacity displacement pump are compared with or without taking into account the power of hydraulic oil compression. Evaluation of power of liquid compression in the pump was made possible by the use of method, proposed by the Author, of determining the degree of liquid aeration in the pump. In the method of determining the liquid aeration in the pump and of powers of volumetric losses of liquid compression a simplified formula (qPvc × ΔpPi)/2 was used describing the field of indicated work of volumetric losses qPvc of liquid compression during one shaft revolution at indicated increase ΔpPi of pressure in the chambers. Three methods were used for comparing the sum of powers of volumetric losses ΔPPvl due to leakage and ΔPPvc of compression and also ΔPPm|ΔpPi of mechanical losses resulting from increase ΔpPi of indicated pressure in the working chambers.

Słowa kluczowe

  • hydrostatic drive
  • variable capacity displacement pump
  • volumetric losses of hydraulic oil
Otwarty dostęp

Identification Of Damages Of Tribological Associations In Crankshaft And Piston Systems Of Two-Stroke Internal Combustion Engines Used As Main Propulsion In Sea-Going Vessels And Proposal Of Probabilistic Description Of Loads As Causes Of These Damages

Data publikacji: 10 Jul 2015
Zakres stron: 44 - 54

Abstrakt

Abstract

The article discusses damages of essential tribological associations in crankshaft and piston systems of large power two-stroke engines used as main engines, which take place during transport tasks performed by those ships. Difficulties are named which make preventing those damages impossible, despite the fact that the technical state of engines of this type is identified with the aid of complex diagnostic systems making use of advanced computer technology. It is demonstrated that one of causes of the damages is the lack of research activities oriented on recognising random properties of the loads leading to those damages. A proposal is made for the loads acting at a given time t on tribological associations in crankshaft and piston systems of internal combustion engines used as main engines to be considered as random variables Qt. At the same time the loads examined within a given time interval tr ≤ t ≤ tz would be considered stochastic processes {Q(t): t ≥ 0}. Essential properties of the loads of the abovementioned tribological associations are named and explained by formulating hypotheses which need empirical verification. Interval estimation is proposed for estimating the expected value E(Qt) of the load Qt acting at time t. A relation is indicated between the mechanical load and the thermal load acting on tribological associations in the ship main engine crankshaft and piston system. A suggestion is formulated that a stochastic form of the relation between these types of load is to be searched for, rather than statistic relation, and a proposal is made to measure the intensity (strength) of the stochastic relation using the Czuprow’s convergence coefficient.

Słowa kluczowe

  • probability
  • friction associations
  • crankshaft and piston system
  • semi-Markov process
  • marine internal combustion engine
  • wear
Otwarty dostęp

Analysing Applicability Of Selected Methods To Smooth Indicator Diagrams Of Marine Medium-Speed Engine

Data publikacji: 10 Jul 2015
Zakres stron: 55 - 61

Abstrakt

Abstract

The article analyses the applicability of selected smoothing methods to smooth indicator diagram curves and to filter disturbances. An intermediate goal of the study was an attempt to extract disturbances recorded during pressure curve smoothing, which are believed to be a source of important diagnostic information.

Within the framework of the reported analysis, a comparison was made between the moving average method, the Savitzky-Golay filter, and the frequency filtration method. The research was performed on a marine medium-speed engine Sulzer 3Al 25/30, which has a relatively long indicator passage.

Słowa kluczowe

  • indicator diagrams
  • smoothing waveforms
  • filtering disturbances
Otwarty dostęp

Clocking In Turbines: Remarks On Physical Nature And Geometric Requirements

Data publikacji: 10 Jul 2015
Zakres stron: 62 - 70

Abstrakt

Abstract

The article discusses two issues relating to the clocking phenomenon in turbines, which are the physical course of stator wake deformation in rotor passages and its further interaction with downstream stator blades, and turbine geometry parameters which are believed to be most favourable for clocking. In both cases, the results presented in the article have made it possible to verify and reformulate the previously accepted opinions.

Słowa kluczowe

  • turbines
  • clocking
  • wakes
  • vortices
  • blade counts
Otwarty dostęp

Simplified Procedure For The Free Vibration Analysis Of Rectangular Plate Structures With Holes And Stiffeners

Data publikacji: 10 Jul 2015
Zakres stron: 71 - 78

Abstrakt

Abstract

Thin and thick plates, plates with holes, stiffened panels and stiffened panels with holes are primary structural members in almost all fields of engineering: civil, mechanical, aerospace, naval, ocean etc. In this paper, a simple and efficient procedure for the free vibration analysis of such elements is presented. It is based on the assumed mode method and can handle different plate thickness, various shapes and sizes of holes, different framing sizes and types as well as different combinations of boundary conditions. Natural frequencies and modes are determined by solving an eigenvalue problem of a multi-degree-of-freedom system matrix equation derived by using Lagrange’s equations. Mindlin theory is applied for a plate and Timoshenko beam theory for stiffeners. The applicability of the method in the design procedure is illustrated with several numerical examples obtained by the in-house developed code VAPS. Very good agreement with standard commercial finite element software is achieved.

Słowa kluczowe

  • energy approach
  • plate with hole
  • stiffened panel
  • thick plate
  • VAPS software
  • free vibration analysis
Otwarty dostęp

Problems Of Determination Of Welding Angular Distortions Of T - Fillet Joints In Ship Hull Structures

Data publikacji: 10 Jul 2015
Zakres stron: 79 - 85

Abstrakt

Abstract

Ship hull structure elements are usually joined by welding. Welding distortions may cause many problems during manufacturing process. In the literature a wide spectrum of suggestions has been proposed for correct estimation of welding deformation, particularly angular ones, in the fillet welded T-joints. In this work a verification of certain methods selected from the literature is presented basing upon the results of the laboratory measurements. To this end, values determined on the basis of engineering hypotheses have been compared with those obtained from the laboratory tests.

Słowa kluczowe

  • welding deformations
  • ship structure welding
  • angular distortions in welded T-joints
Otwarty dostęp

Selected Aspects Of Building, Operation And Environmental Impact Of Offshore Wind Power Electric Plants

Data publikacji: 10 Jul 2015
Zakres stron: 86 - 92

Abstrakt

Abstract

This paper describes essence of work of offshore wind power electric plants and crucial aspects of their building and operating. Prospects for development of global, European and domestic markets of offshore wind power industry have been delineated. A comparative analysis of environmental impact of an offshore and land-based 2MW wind power electric plant has been performed by using LCA method and Ecoindex – 99 (Ekowskaźnik 99) modelling.

Słowa kluczowe

  • wind energy
  • offshore wind power electric plants
  • LCA method
  • Ekowskaźnik 99 (Ecoindex - 99)
Otwarty dostęp

Mathematical Modelling Of Elastic Deflection Of A Tubular Cross-Section

Data publikacji: 10 Jul 2015
Zakres stron: 93 - 100

Abstrakt

Abstract

Cutting a tubular element into thin rings is an operation often used in engineering processes. Total work of the cutting consists of that necessary for initial deflection of cut material and the cutting work itself. This paper presents mathematical models which describe deflection of cross-section of a single tubular element as well as a single layer of tubes under action of external forces (acting and reacting ones). The deflection concerns end part of tube hence the cutting object model has been reduced to a thin ring. Results of calculation by using the developed models are presented for selected materials of tubular elements, which are commonly used for structures of the kind; moreover, they are prepared in a form of dimensionless diagrams, that makes it possible to use them for an arbitrary material.

Słowa kluczowe

  • mathematical modelling of elastic deflection
  • tubular elements
  • deflection of a ring under action of external forces
Otwarty dostęp

Low Temperature Properties Of Fuel Mixtures Of Kerosene And Fame Type Used To Supply Turbine Engines In Marine And Other Non-Aeronautical Applications

Data publikacji: 10 Jul 2015
Zakres stron: 101 - 105

Abstrakt

Abstract

A worldwide trend to popularise gradually increasing use of biofuels in various applications was a motivation for gaining interest in FAME as a commonly available biocomponent to fuels combusted in turbine engines. These engines are mainly used in aeronautics, but many of them are also used in other, non-aeronautical areas, including marine navigation. Specific conditions in which fuels are combusted in turbine engines used in these applications are the reason why fuel mixtures of kerosene and FAME type should reveal relevant low temperature characteristics. The article presents results of tests of low temperature properties of mixtures of the jet fuel Jet A-1 and methyl esters of higher fatty acids (FAME). The prepared mixtures contained different contents of FAME. The obtained results present changes of: viscosity, cloud point, pour point, crystallising point, and cold filter plugging point, depending on the percentage by volume of FAME. They also prove that the course of changes of low temperature properties of these mixtures is affected by chemical structure of the biocomponent.

Słowa kluczowe

  • jet fuel
  • biocomponents
  • marine turbine engine
  • low temperature properties

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