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Journal & Issues

Volume 52 (2022): Issue 4 (December 2022)

Volume 52 (2022): Issue 3 (September 2022)

Volume 52 (2022): Issue 2 (June 2022)

Volume 52 (2022): Issue 1 (March 2022)

Volume 51 (2021): Issue 4 (December 2021)

Volume 51 (2021): Issue 3 (October 2021)

Volume 51 (2021): Issue 2 (June 2021)

Volume 51 (2021): Issue 1 (March 2021)

Volume 50 (2020): Issue 4 (December 2020)

Volume 50 (2020): Issue 3 (October 2020)

Volume 50 (2020): Issue 2 (June 2020)

Volume 50 (2020): Issue 1 (March 2020)

Volume 49 (2019): Issue 4 (December 2019)

Volume 49 (2019): Issue 3 (October 2019)

Volume 49 (2019): Issue 2 (June 2019)

Volume 49 (2019): Issue 1 (March 2019)

Volume 48 (2018): Issue 1 (December 2018)

Volume 47 (2018): Issue 1 (December 2018)

Volume 46 (2018): Issue 1 (June 2018)

Volume 45 (2018): Issue 1 (March 2018)

Volume 44 (2017): Issue 1 (December 2017)

Volume 43 (2017): Issue 1 (October 2017)

Volume 42 (2017): Issue 1 (June 2017)

Volume 41 (2017): Issue 1 (March 2017)

Volume 40 (2016): Issue 1 (December 2016)

Volume 39 (2016): Issue 1 (October 2016)

Volume 38 (2016): Issue 1 (October 2016)

Volume 37 (2016): Issue 1 (July 2016)

Volume 36 (2015): Issue 1 (December 2015)

Volume 35 (2015): Issue 1 (November 2015)

Volume 34 (2015): Issue 1 (September 2015)

Volume 33 (2015): Issue 1 (September 2015)

Volume 32 (2014): Issue 1 (December 2014)

Volume 31 (2014): Issue 1 (September 2014)

Volume 30 (2014): Issue 1 (June 2014)

Volume 29 (2014): Issue 1 (March 2014)

Volume 27 (2014): Issue 1 (February 2014)

Volume 26 (2013): Issue 1 (June 2013)

Volume 25 (2013): Issue 1 (March 2013)

Volume 24 (2012): Issue 1 (December 2012)

Volume 23 (2012): Issue 1 (September 2012)

Volume 22 (2012): Issue 1 (June 2012)

Volume 21 (2012): Issue 1 (March 2012)

Volume 20 (2012): Issue 1 (January 2012)

Volume 14-15 (2010): Issue 2010 (December 2010)

Volume 13 (2010): Issue 1 (January 2010)

Volume 11-12 (2009): Issue 1 (December 2009)

Volume 9-10 (2009): Issue 1 (January 2009)

Volume 8 (2008): Issue 1 (December 2008)

Volume 7 (2008): Issue 4 (December 2008)

Volume 6 (2008): Issue 3 (September 2008)

Volume 5 (2008): Issue 2 (June 2008)

Volume 4 (2008): Issue 1 (March 2008)

Volume 3 (2007): Issue 2007 (January 2007)

Journal Details
Format
Journal
eISSN
2083-4608
First Published
26 Feb 2008
Publication timeframe
4 times per year
Languages
English

Search

Volume 51 (2021): Issue 1 (March 2021)

Journal Details
Format
Journal
eISSN
2083-4608
First Published
26 Feb 2008
Publication timeframe
4 times per year
Languages
English

Search

17 Articles
Open Access

Technical and Economic Analysis of the Consequences of Occupational Injuries at Machine-Building Enterprises

Published Online: 06 Apr 2021
Page range: 1 - 13

Abstract

Abstract

The article shows that effective organization of occupational health and safety (OHS) at industrial enterprises have not only social, but also technical and economic consequences. Analysis of the dependences of the frequency and the severity coefficients of occupational injuries on the cost of OHS measures allowed to draw an important conclusion, that with insufficient funding for injuries protection, the level of injuries remains high enough, and with increasing OHS funds the level of injuries decreases significantly. However, there comes a situation, when further economic stimulation of injuries protection measures does not yield significant results. Definition of technical and economic criteria for assessing the production system from occupational safety indicators is proposed using the apparatus of the probability and queuing theories. An example of calculating the downtime of process equipment due to occupational injuries in the shop of mechanical engineering plant is considered.

Keywords

  • occupational health and safety (OHS)
  • occupational injuries
  • queuing theory
  • industrial productivity
  • equipment dowtime
Open Access

The Analysis of Organizational and Legal Possibilities to Reduce the Dangers Related to Road Transport of Dangerous Goods in Poland

Published Online: 06 Apr 2021
Page range: 15 - 28

Abstract

Abstract

According to the data of the Supreme Audit Office, every day in Poland, 20 thousand of vehicles transport dangerous goods by road. Annually 150 million tons of dangerous goods are transported, including flammable, explosive, corrosive, toxic and radioactive materials. The article presents an analysis of aggregated data obtained from particular institutions, participating in different way in monitoring and controlling transport of this type of goods. The analysis of combined data has enabled the identification of organizational and legal possibilities for reducing the dangers associated with the road transport of dangerous goods in Poland.

Keywords

  • ADR
  • road safety
  • transport of dangerous goods
Open Access

Zn-Cr Alloy Coatings: Electrodeposition and Properties

Published Online: 06 Apr 2021
Page range: 29 - 42

Abstract

Abstract

The electrodeposition process of Zn-Cr alloy coatings under the conditions of direct and pulsed current is discussed. The Cr content in the obtained alloy coatings, the current efficiency of the process, surface morphology, structure and wettability as a function of deposition parameters, such as current density, were determined. The Zn-Cr alloy coatings of good quality contained up to 20 wt.% Cr (for direct current) and up to 9 wt.% Cr (for pulse current). All the obtained coatings had a structure typical of zinc coatings (h.c.p.) and had a hydrophobic character. The morphology of the coatings changed significantly under the influence of changes in deposition conditions.

Keywords

  • electrodeposition
  • Zn-Cr alloy coatings
  • hydrophobic
Open Access

Boosting Trees in Application to Hand Grenades Fuzes

Published Online: 06 Apr 2021
Page range: 43 - 55

Abstract

Abstract

The article in the introduction presents a brief description of the decision tree, and the purpose of the article was defined. Then, the process of building boosting trees was characterized, paying attention to the algorithm of their building. A method of building boosting trees for UZRGM fuzes is described. The assortment of fuzes in which this type of fuze is used is indicated, and the individual features of the fuze are presented, which are checked during laboratory diagnostic tests. The importance classes that were used to classify the revealed inconsistencies were also described. A boosting classification tree for UZRGM fuzes was designed and built. An exemplary graph of the built tree and its structure and also a fragment of specific values predicted in individual analyzed classes are shown. The matrix of incorrect classifications was determined, which determines the accuracy of the incorrect predictions. On selected examples of the analyzed classes, the designed model was assessed on the basis of the lift chart and gains chart.

Keywords

  • boosting trees
  • artificial intelligence
  • feature
  • prediction
  • fuze
Open Access

Human Safety in Autonomous Transport Systems – Review and Case Study

Published Online: 06 Apr 2021
Page range: 57 - 71

Abstract

Abstract

During the robot's operational tasks, a key issue is its reliability in the aspect of human safety providing. Currently, there are a number of methods used to detect people, and their selection most often depends on the type of process carried out by robots. Therefore, the article is focused on the development of a comparative analysis of selected methods of human detection in the storage area. The main aspect in the context of which these systems were compared concerned the safety of robotic systems in the space of human occurrence. Main advantages and drawbacks of the methods in various applications were presented. The detailed analysis of the achievements in this area gives the possibility to identify research gaps and possible future research directions when using these tools in autonomous warehouses designing processes.

Keywords

  • object detection system
  • safety
  • human detection
  • autonomous transport
  • warehouse
  • review
Open Access

K-Graph: Knowledgeable Graph for Text Documents

Published Online: 06 Apr 2021
Page range: 73 - 89

Abstract

Abstract

Graph databases are applied in many applications, including science and business, due to their low-complexity, low-overheads, and lower time-complexity. The graph-based storage offers the advantage of capturing the semantic and structural information rather than simply using the Bag-of-Words technique. An approach called Knowledgeable graphs (K-Graph) is proposed to capture semantic knowledge. Documents are stored using graph nodes. Thanks to weighted subgraphs, the frequent subgraphs are extracted and stored in the Fast Embedding Referral Table (FERT). The table is maintained at different levels according to the headings and subheadings of the documents. It reduces the memory overhead, retrieval, and access time of the subgraph needed. The authors propose an approach that will reduce the data redundancy to a larger extent. With real-world datasets, K-graph’s performance and power usage are threefold greater than the current methods. Ninety-nine per cent accuracy demonstrates the robustness of the proposed algorithm.

Keywords

  • subgraph mining
  • graph database
  • text classification
Open Access

Analysis of the Operating Modes of the Stationary Energy Storage Device in DC Railway Power Supply System

Published Online: 06 Apr 2021
Page range: 91 - 104

Abstract

Abstract

This article analyzes the operating modes of the energy storage. The aim was to conduct laboratory tests in conditions similar to real energy storage and to analyze its basic electrical parameters. A special measuring system has been created for laboratory testing. Real tests took place in the traction substation in Mińsk Mazowiecki, where the energy storage was included in the traction substation system. Based on the laboratory tests carried out and in real conditions it was found that the use of energy storage in the electric traction supply system is justified. It is adapted to work as a device supporting the operation of the traction substation and the section cabin.

Keywords

  • energy storage
  • supercapacitors
  • traction substation
  • section cabin
Open Access

Operations & Maintenance of the Aircraft Arresting Gear Systems in the Polish Air Force. Part 1

Published Online: 06 Apr 2021
Page range: 105 - 124

Abstract

Abstract

In the article, the authors reviewed the arresting gears used in military aviation. The second part of this part describes the operation concept that is used in the Polish Air Force, in relation to the two types of gears, namely the post-Soviet ones that are still in service, and the second one: of U.S. production obtained due to the purchase of F-16 aircraft. The authors emphasize that in the case of an appropriate operation system, it is possible to extend the service life of devices and maintain safety of the air operations.

Keywords

  • safety
  • reliability
  • operations & maintenance
  • air transport
  • aircraft arresting gear systems
  • airport arresting devices
Open Access

Research Methodology of the Sleeve-Target System with Miss Distance Indicator of the Unmanned Aerial Target Imitator

Published Online: 06 Apr 2021
Page range: 125 - 147

Abstract

Abstract

The article presents the method of using a modified acoustic miss distance indicator applied together with the set of controlled aerial target imitators (ZSMCP) Jaskółka “Swallow” operated in the Polish Armed Forces. The described method enables the implementation of controlling and testing the new CZT imitators and inspect the technical condition of these, which are still operated.

Keywords

  • miss distance indicator
  • sleeve-target system
  • aerial target imitator
  • anti-aircraft fire
Open Access

Simulation of a Motor Vehicle Momentarily Accelerating in Various Road Conditions

Published Online: 06 Apr 2021
Page range: 149 - 158

Abstract

Abstract

In this paper some selected conclusions have been drawn from the simulated maneuver of a vehicle’s momentary acceleration in various road conditions. The aim of this paper was to answer the question whether the random irregularities of the road could decrease the final speed of the vehicle and cause it to deviate from the straight line motion and to what extent. These irregularities had three different maximum amplitudes which enabled analysis of vehicle’s acceleration on the less and the more uneven road. Also, almost the same and almost different profiles were assumed for the left and the right wheels of the vehicle’s model.

Some additional phenomena such as the ice on the road have been taken into account. The initial speed was 20 km/h and after 2 s the vehicle started to accelerate. Then, after 8 s the simulation stopped, which gave the whole simulation time equal to 10 s.

Keywords

  • vehicle’s acceleration
  • road irregularities
Open Access

Safety and Functionality Assessment of Tram Loops in Wrocław

Published Online: 06 Apr 2021
Page range: 159 - 172

Abstract

Abstract

The article presents the implementation of the ISFTL method proposed by the authors consisting in an indicator assessment of the safety and functionality of tram loops. Five tram loops located in Wrocław were analyzed. Each of these loops has different characteristics. The components of each assessment are described in detail and further directions for improving the proposed assessment are indicated.

Keywords

  • safety
  • public transport
  • tram loop
Open Access

Corrosion Testing of Kinematic Connection Details from the Jet Engine in a Seawater Environment

Published Online: 06 Apr 2021
Page range: 173 - 193

Abstract

Abstract

Corrosion is a worldwide problem, posing a threat to the safe operation of machinery and equipment. In this article has been analyzed the problem of corrosion on selected elements of the aircraft engine. At the beginning, are discussed the types of corrosion, as well as the materials from which were made the examined parts. The sensitive kinematic vapor from the jet engine was examined in three different galvanic coatings and in the state without any anti-corrosion coating in order to check the effectiveness of galvanic coatings. The results of the NSS tests were then illustrated and discussed. On the basis of the obtained test results, were formulated final conclusions.

Keywords

  • test
  • transport
  • coating
  • phosphorus
  • steel
Open Access

Driver's Tasks in the Context of the Increase in the Degree of Automation of Road Transport

Published Online: 06 Apr 2021
Page range: 195 - 211

Abstract

Abstract

The publication adopts the SAE J3016 standard as the one that defines the level of vehicle autonomy. Gradually, the role of the driver, especially in terms of driving, will decrease, and the last 5th degree of automation will be achieved thanks to the complete elimination of the driver. Through the broadly understood research in the field of drivers' tasks (literature, information from enterprises and labor offices, face-to-face interviews), it can be stated that not all of them will be able to implement autonomous vehicles.

Keywords

  • autonomous vehicles
  • transport
  • drivers' tasks
Open Access

Markov model of the operations & maintenance process of vehicles scheduled to be Operated

Published Online: 06 Apr 2021
Page range: 213 - 223

Abstract

Abstract

The article is dedicated to the modelling of operations & maintenance of vehicles scheduled to be operated. This specific feature is illustrative of the vehicle operation process in the military system. The presented model of the operation process of vehicles scheduled to be operated, using the Markov chain theory, contains indicators and measures essential for the vehicle operation, i.e. repair defectiveness, repair intensity, usage intensity and failure intensity. This model enables to quantify the impact of the introduced changes in operational practice or changes planned as a forecast, which is shown in the examples.

Keywords

  • Markov processes
  • modelling
  • operation processes
  • vehicles
  • readiness
  • assessment
  • analysis
Open Access

Reliability Estimation of a Network Structure Using Generalized Trapezoidal Fuzzy Numbers

Published Online: 06 Apr 2021
Page range: 225 - 241

Abstract

Abstract

Classical sets are used commonly to consider reliability. Because of the uncertainty in the data (which considered in the present paper) classical sets fail to describe the reliability accurately. Uncertainty leads to fluctuation in the actual situation of the structure. Fuzzy logic method attempts to test system reliability with the benefit of membership function. Within this context, specific problems of reasoning-based approaches are studied, explored and correlated with standard reliability approaches. In this paper Generalized Trapezoidal Fuzzy numbers (GTrFN) are used to assess the structure's fuzzy reliability. The reliability of each event is assigned with different level of satisfaction and some improved operations on the generalized trapezoidal fuzzy numbers (GTrFN) are used to calculate the fuzzy boundaries for the resultant reliability of the final event along with the degree of satisfaction. Also the results are compared to demonstrate the application of the improved operations on Generalized Trapezoidal Fuzzy Numbers (GTrFN). The obtained results converge to more precise interval values as compare to the vague fuzzy number.

Keywords

  • classical Sets
  • fuzzy sets
  • reliability
  • Fault Tree Analysis (FTA)
  • Generalized Trapezoidal
  • fuzzy number
  • arithmetic operations
  • DC power supply
Open Access

Turbine Engines Trend Development

Published Online: 06 Apr 2021
Page range: 243 - 254

Abstract

Abstract

The aim of the following article is to define the directions of development of aviation turbine engines. It was assumed that these directions would determine the increase in pressure ratio and fuel combustion temperature as parameters determining the efficiency of the Brayton cycle.

Keywords

  • turbine aircraft engines
  • jet engine designs
  • development of turbine engines
Open Access

Is Mean Time to Failure (MTTF) Equal to Mean Time of Life for Unrepairable Systems?

Published Online: 06 Apr 2021
Page range: 255 - 264

Abstract

Abstract

One of the most important reliability parameters is the mean time to failure (MTTF). It is widely accepted that the MTTF is equal to the mean time of life ET. This article shows that this is not necessarily true. Although for the most commonly used statistical distributions (such as exponential, Gaussian, chi-square, Fisher-Tippett distributions) the values of MTTF and ET are equal, this is not the case for the log-normal distribution. Similarity, some less commonly used distributions (such as Breit-Wigner distribution) may also require calculation adjustments resulting from MTTF ≠ ET. Ignoring this discrepancy, an erroneous MTTF value can be obtained.

Keywords

  • reliability
  • mean time to failure
  • mean time of life
17 Articles
Open Access

Technical and Economic Analysis of the Consequences of Occupational Injuries at Machine-Building Enterprises

Published Online: 06 Apr 2021
Page range: 1 - 13

Abstract

Abstract

The article shows that effective organization of occupational health and safety (OHS) at industrial enterprises have not only social, but also technical and economic consequences. Analysis of the dependences of the frequency and the severity coefficients of occupational injuries on the cost of OHS measures allowed to draw an important conclusion, that with insufficient funding for injuries protection, the level of injuries remains high enough, and with increasing OHS funds the level of injuries decreases significantly. However, there comes a situation, when further economic stimulation of injuries protection measures does not yield significant results. Definition of technical and economic criteria for assessing the production system from occupational safety indicators is proposed using the apparatus of the probability and queuing theories. An example of calculating the downtime of process equipment due to occupational injuries in the shop of mechanical engineering plant is considered.

Keywords

  • occupational health and safety (OHS)
  • occupational injuries
  • queuing theory
  • industrial productivity
  • equipment dowtime
Open Access

The Analysis of Organizational and Legal Possibilities to Reduce the Dangers Related to Road Transport of Dangerous Goods in Poland

Published Online: 06 Apr 2021
Page range: 15 - 28

Abstract

Abstract

According to the data of the Supreme Audit Office, every day in Poland, 20 thousand of vehicles transport dangerous goods by road. Annually 150 million tons of dangerous goods are transported, including flammable, explosive, corrosive, toxic and radioactive materials. The article presents an analysis of aggregated data obtained from particular institutions, participating in different way in monitoring and controlling transport of this type of goods. The analysis of combined data has enabled the identification of organizational and legal possibilities for reducing the dangers associated with the road transport of dangerous goods in Poland.

Keywords

  • ADR
  • road safety
  • transport of dangerous goods
Open Access

Zn-Cr Alloy Coatings: Electrodeposition and Properties

Published Online: 06 Apr 2021
Page range: 29 - 42

Abstract

Abstract

The electrodeposition process of Zn-Cr alloy coatings under the conditions of direct and pulsed current is discussed. The Cr content in the obtained alloy coatings, the current efficiency of the process, surface morphology, structure and wettability as a function of deposition parameters, such as current density, were determined. The Zn-Cr alloy coatings of good quality contained up to 20 wt.% Cr (for direct current) and up to 9 wt.% Cr (for pulse current). All the obtained coatings had a structure typical of zinc coatings (h.c.p.) and had a hydrophobic character. The morphology of the coatings changed significantly under the influence of changes in deposition conditions.

Keywords

  • electrodeposition
  • Zn-Cr alloy coatings
  • hydrophobic
Open Access

Boosting Trees in Application to Hand Grenades Fuzes

Published Online: 06 Apr 2021
Page range: 43 - 55

Abstract

Abstract

The article in the introduction presents a brief description of the decision tree, and the purpose of the article was defined. Then, the process of building boosting trees was characterized, paying attention to the algorithm of their building. A method of building boosting trees for UZRGM fuzes is described. The assortment of fuzes in which this type of fuze is used is indicated, and the individual features of the fuze are presented, which are checked during laboratory diagnostic tests. The importance classes that were used to classify the revealed inconsistencies were also described. A boosting classification tree for UZRGM fuzes was designed and built. An exemplary graph of the built tree and its structure and also a fragment of specific values predicted in individual analyzed classes are shown. The matrix of incorrect classifications was determined, which determines the accuracy of the incorrect predictions. On selected examples of the analyzed classes, the designed model was assessed on the basis of the lift chart and gains chart.

Keywords

  • boosting trees
  • artificial intelligence
  • feature
  • prediction
  • fuze
Open Access

Human Safety in Autonomous Transport Systems – Review and Case Study

Published Online: 06 Apr 2021
Page range: 57 - 71

Abstract

Abstract

During the robot's operational tasks, a key issue is its reliability in the aspect of human safety providing. Currently, there are a number of methods used to detect people, and their selection most often depends on the type of process carried out by robots. Therefore, the article is focused on the development of a comparative analysis of selected methods of human detection in the storage area. The main aspect in the context of which these systems were compared concerned the safety of robotic systems in the space of human occurrence. Main advantages and drawbacks of the methods in various applications were presented. The detailed analysis of the achievements in this area gives the possibility to identify research gaps and possible future research directions when using these tools in autonomous warehouses designing processes.

Keywords

  • object detection system
  • safety
  • human detection
  • autonomous transport
  • warehouse
  • review
Open Access

K-Graph: Knowledgeable Graph for Text Documents

Published Online: 06 Apr 2021
Page range: 73 - 89

Abstract

Abstract

Graph databases are applied in many applications, including science and business, due to their low-complexity, low-overheads, and lower time-complexity. The graph-based storage offers the advantage of capturing the semantic and structural information rather than simply using the Bag-of-Words technique. An approach called Knowledgeable graphs (K-Graph) is proposed to capture semantic knowledge. Documents are stored using graph nodes. Thanks to weighted subgraphs, the frequent subgraphs are extracted and stored in the Fast Embedding Referral Table (FERT). The table is maintained at different levels according to the headings and subheadings of the documents. It reduces the memory overhead, retrieval, and access time of the subgraph needed. The authors propose an approach that will reduce the data redundancy to a larger extent. With real-world datasets, K-graph’s performance and power usage are threefold greater than the current methods. Ninety-nine per cent accuracy demonstrates the robustness of the proposed algorithm.

Keywords

  • subgraph mining
  • graph database
  • text classification
Open Access

Analysis of the Operating Modes of the Stationary Energy Storage Device in DC Railway Power Supply System

Published Online: 06 Apr 2021
Page range: 91 - 104

Abstract

Abstract

This article analyzes the operating modes of the energy storage. The aim was to conduct laboratory tests in conditions similar to real energy storage and to analyze its basic electrical parameters. A special measuring system has been created for laboratory testing. Real tests took place in the traction substation in Mińsk Mazowiecki, where the energy storage was included in the traction substation system. Based on the laboratory tests carried out and in real conditions it was found that the use of energy storage in the electric traction supply system is justified. It is adapted to work as a device supporting the operation of the traction substation and the section cabin.

Keywords

  • energy storage
  • supercapacitors
  • traction substation
  • section cabin
Open Access

Operations & Maintenance of the Aircraft Arresting Gear Systems in the Polish Air Force. Part 1

Published Online: 06 Apr 2021
Page range: 105 - 124

Abstract

Abstract

In the article, the authors reviewed the arresting gears used in military aviation. The second part of this part describes the operation concept that is used in the Polish Air Force, in relation to the two types of gears, namely the post-Soviet ones that are still in service, and the second one: of U.S. production obtained due to the purchase of F-16 aircraft. The authors emphasize that in the case of an appropriate operation system, it is possible to extend the service life of devices and maintain safety of the air operations.

Keywords

  • safety
  • reliability
  • operations & maintenance
  • air transport
  • aircraft arresting gear systems
  • airport arresting devices
Open Access

Research Methodology of the Sleeve-Target System with Miss Distance Indicator of the Unmanned Aerial Target Imitator

Published Online: 06 Apr 2021
Page range: 125 - 147

Abstract

Abstract

The article presents the method of using a modified acoustic miss distance indicator applied together with the set of controlled aerial target imitators (ZSMCP) Jaskółka “Swallow” operated in the Polish Armed Forces. The described method enables the implementation of controlling and testing the new CZT imitators and inspect the technical condition of these, which are still operated.

Keywords

  • miss distance indicator
  • sleeve-target system
  • aerial target imitator
  • anti-aircraft fire
Open Access

Simulation of a Motor Vehicle Momentarily Accelerating in Various Road Conditions

Published Online: 06 Apr 2021
Page range: 149 - 158

Abstract

Abstract

In this paper some selected conclusions have been drawn from the simulated maneuver of a vehicle’s momentary acceleration in various road conditions. The aim of this paper was to answer the question whether the random irregularities of the road could decrease the final speed of the vehicle and cause it to deviate from the straight line motion and to what extent. These irregularities had three different maximum amplitudes which enabled analysis of vehicle’s acceleration on the less and the more uneven road. Also, almost the same and almost different profiles were assumed for the left and the right wheels of the vehicle’s model.

Some additional phenomena such as the ice on the road have been taken into account. The initial speed was 20 km/h and after 2 s the vehicle started to accelerate. Then, after 8 s the simulation stopped, which gave the whole simulation time equal to 10 s.

Keywords

  • vehicle’s acceleration
  • road irregularities
Open Access

Safety and Functionality Assessment of Tram Loops in Wrocław

Published Online: 06 Apr 2021
Page range: 159 - 172

Abstract

Abstract

The article presents the implementation of the ISFTL method proposed by the authors consisting in an indicator assessment of the safety and functionality of tram loops. Five tram loops located in Wrocław were analyzed. Each of these loops has different characteristics. The components of each assessment are described in detail and further directions for improving the proposed assessment are indicated.

Keywords

  • safety
  • public transport
  • tram loop
Open Access

Corrosion Testing of Kinematic Connection Details from the Jet Engine in a Seawater Environment

Published Online: 06 Apr 2021
Page range: 173 - 193

Abstract

Abstract

Corrosion is a worldwide problem, posing a threat to the safe operation of machinery and equipment. In this article has been analyzed the problem of corrosion on selected elements of the aircraft engine. At the beginning, are discussed the types of corrosion, as well as the materials from which were made the examined parts. The sensitive kinematic vapor from the jet engine was examined in three different galvanic coatings and in the state without any anti-corrosion coating in order to check the effectiveness of galvanic coatings. The results of the NSS tests were then illustrated and discussed. On the basis of the obtained test results, were formulated final conclusions.

Keywords

  • test
  • transport
  • coating
  • phosphorus
  • steel
Open Access

Driver's Tasks in the Context of the Increase in the Degree of Automation of Road Transport

Published Online: 06 Apr 2021
Page range: 195 - 211

Abstract

Abstract

The publication adopts the SAE J3016 standard as the one that defines the level of vehicle autonomy. Gradually, the role of the driver, especially in terms of driving, will decrease, and the last 5th degree of automation will be achieved thanks to the complete elimination of the driver. Through the broadly understood research in the field of drivers' tasks (literature, information from enterprises and labor offices, face-to-face interviews), it can be stated that not all of them will be able to implement autonomous vehicles.

Keywords

  • autonomous vehicles
  • transport
  • drivers' tasks
Open Access

Markov model of the operations & maintenance process of vehicles scheduled to be Operated

Published Online: 06 Apr 2021
Page range: 213 - 223

Abstract

Abstract

The article is dedicated to the modelling of operations & maintenance of vehicles scheduled to be operated. This specific feature is illustrative of the vehicle operation process in the military system. The presented model of the operation process of vehicles scheduled to be operated, using the Markov chain theory, contains indicators and measures essential for the vehicle operation, i.e. repair defectiveness, repair intensity, usage intensity and failure intensity. This model enables to quantify the impact of the introduced changes in operational practice or changes planned as a forecast, which is shown in the examples.

Keywords

  • Markov processes
  • modelling
  • operation processes
  • vehicles
  • readiness
  • assessment
  • analysis
Open Access

Reliability Estimation of a Network Structure Using Generalized Trapezoidal Fuzzy Numbers

Published Online: 06 Apr 2021
Page range: 225 - 241

Abstract

Abstract

Classical sets are used commonly to consider reliability. Because of the uncertainty in the data (which considered in the present paper) classical sets fail to describe the reliability accurately. Uncertainty leads to fluctuation in the actual situation of the structure. Fuzzy logic method attempts to test system reliability with the benefit of membership function. Within this context, specific problems of reasoning-based approaches are studied, explored and correlated with standard reliability approaches. In this paper Generalized Trapezoidal Fuzzy numbers (GTrFN) are used to assess the structure's fuzzy reliability. The reliability of each event is assigned with different level of satisfaction and some improved operations on the generalized trapezoidal fuzzy numbers (GTrFN) are used to calculate the fuzzy boundaries for the resultant reliability of the final event along with the degree of satisfaction. Also the results are compared to demonstrate the application of the improved operations on Generalized Trapezoidal Fuzzy Numbers (GTrFN). The obtained results converge to more precise interval values as compare to the vague fuzzy number.

Keywords

  • classical Sets
  • fuzzy sets
  • reliability
  • Fault Tree Analysis (FTA)
  • Generalized Trapezoidal
  • fuzzy number
  • arithmetic operations
  • DC power supply
Open Access

Turbine Engines Trend Development

Published Online: 06 Apr 2021
Page range: 243 - 254

Abstract

Abstract

The aim of the following article is to define the directions of development of aviation turbine engines. It was assumed that these directions would determine the increase in pressure ratio and fuel combustion temperature as parameters determining the efficiency of the Brayton cycle.

Keywords

  • turbine aircraft engines
  • jet engine designs
  • development of turbine engines
Open Access

Is Mean Time to Failure (MTTF) Equal to Mean Time of Life for Unrepairable Systems?

Published Online: 06 Apr 2021
Page range: 255 - 264

Abstract

Abstract

One of the most important reliability parameters is the mean time to failure (MTTF). It is widely accepted that the MTTF is equal to the mean time of life ET. This article shows that this is not necessarily true. Although for the most commonly used statistical distributions (such as exponential, Gaussian, chi-square, Fisher-Tippett distributions) the values of MTTF and ET are equal, this is not the case for the log-normal distribution. Similarity, some less commonly used distributions (such as Breit-Wigner distribution) may also require calculation adjustments resulting from MTTF ≠ ET. Ignoring this discrepancy, an erroneous MTTF value can be obtained.

Keywords

  • reliability
  • mean time to failure
  • mean time of life

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