The paper deals with the issue of mechanical strength of climbing ropes. These ropes are exposed ... more The paper deals with the issue of mechanical strength of climbing ropes. These ropes are exposed to the influence of exploitation factors both during training and in rescue operations. Among others, they may sustain mechanical, thermal and chemical damage. The study attempted to provide an evaluation of the effect this damage has on the mechanical strength and extensibility of ropes. The tests were carried out in laboratory conditions, and the courses of force in the function of deformation and impact of force on deformation were recorded. An unfavourable influence of some types of damage on the strength and extensibility of ropes was demonstrated. Mechanical and thermal stresses mainly cause damage to the rope sheath. Their effect on endurance is similar. The remaining strength of the rope is slightly above the minimum allowable tensile strength. On the other hand, the chemical treatment did not cause a noticeable decrease in the rope’s strength.
International Journal of Environmental Research and Public Health
Orthodontic retention is the final important stage of orthodontic treatment, the aim of which is ... more Orthodontic retention is the final important stage of orthodontic treatment, the aim of which is to consolidate the functional and aesthetic position of teeth. Among adults, fixed retainers made of different types of wires are the most common. The aim of this study was to analyse the mechanical properties of a new generation of fixed orthodontic retainers—printed by 3D printers. Materials and Methods: The study was conducted using samples made of Nextdent MFH C&B N1 resin in the form of cuboid bars with nominal dimensions of width b = 3 mm, thickness d = 0.8 mm; 1 mm; 1.2 mm, length l = 30 mm for each type. The influence of the thickness of the retainers on their strength under loaded conditions was evaluated. Flexural strength, elastic properties, deflection, and creep were compared. The samples were aged in an artificial saliva bath at 37 ± 1 °C during the strength tests. Results: It was shown that differences in the thickness of the samples affected their elastic and strength pro...
With the constant growth of requirements to the quality of infocommunication services, special at... more With the constant growth of requirements to the quality of infocommunication services, special attention is paid to the management of information transfer in wireless self-organizing networks. The clustering algorithm based on the Motley signal propagation model has been improved, resulting in cluster formation based on the criterion of shortest distance and maximum signal power value. It is shown that the use of the improved clustering algorithm compared to its classical version is more efficient for the route search process. Ant and simulated annealing algorithms are presented to perform route search in a wireless sensor network based on the value of the quality of service parameter. A comprehensive routing method based on finding the global extremum of an ordered random search with node addition/removal is proposed by using the presented ant and simulated annealing algorithms. It is shown that the integration of the proposed clustering and routing solutions can reduce the route s...
The quality and reliability of consumables, including gear oils, results in the failure-free oper... more The quality and reliability of consumables, including gear oils, results in the failure-free operation of the transmission components in heavy trucks. It is known that oil viscosity is essential for all lubricated tribopairs for wear and friction reduction in all vehicles with a gearbox. Viscosity may be influenced by the contamination that wear products can impart on the oil. Oil contamination can also affect lubrication efficiency in the boundary friction conditions in gearboxes where slips occur (including bevel and hypoid gearboxes). The present research focused on this issue. An obvious hypothesis was adopted, where it was theorized that exploiting the contaminants that are present in gear oil may affect how the lubricating properties of gear oils deteriorate. Laboratory tests were performed on contaminants that are commonly found in gear oil using the Parker Laser CM20. The study was designed to identify a number of different solid particles that are present in oil. At the sec...
In the article the application of Bayesian probabilistic modeling was presented as a way to stand... more In the article the application of Bayesian probabilistic modeling was presented as a way to standardize analytics of measurement results, which completes the operational and procedural standardization of determining the strength of dental composites. The traditional way of conducting studies of strength performed as services and calculations, and which do not refer to previous studies, was changed into an adaptation process of knowledge accumulation in a form of an increasing precise models. Probabilistic flexural strength models were used to create a reliability ranking of studied dental composites. Conceptualization of reliability of a biotechnological system, such as a “tooth-dental composite” required the expansion of the notion of“failure” with random events involving the occurrence of compatibility failure.
The aim of the study was to compare microhardness and wear resistance of ceramic-polymer composit... more The aim of the study was to compare microhardness and wear resistance of ceramic-polymer composites with micro and nano-hybrid structure. For the studies commercial composites were used, containing filler particles of the same type but different sizes, nano-sized (Filtek Ultimate) and micro-sized (Filtek Z250) composites. Tribological testing was conducted using ball-on-disc micro-tribometer. Vickers testing method was applied for microhardness studies with the use of Futertech FM 700 device. It has been demonstrated that the wear of Filtek Ultimate is almost twice lower in comparison to wear of Filtek Z250 composite. It has been concluded that the use of filler nanoparticles significantly increased wear resistance of the material. Additionally, lack of correlation between material microhardness and wear resistance has been demonstrated.
The paper presents analysis of the availability of medium firefighting and rescue vehicles chassi... more The paper presents analysis of the availability of medium firefighting and rescue vehicles chassis used by State Fire Brigade in Warsaw. For analysis of availability of vehicles chassis the technical availability factor has been used. Additionally, in the paper time to restore of the vehicles chassis regarding causes of unavailability has been presented. In the tests the data obtained from the Decision Support System (DSS) of Warsaw State Fire Brigade were applied. The research included the period from January 2012 to May 2015. Based on the results, it can be statement that the operating mileage is the crucial factor of operating degradation of firefighting vehicles chassis.
In this paper the reliability assessment of structural reliability of the selected light-cured de... more In this paper the reliability assessment of structural reliability of the selected light-cured dental composites based on the biaxial flexural strength test results has been presented. A two-parameter Weibull distribution was applied as a reliability model in order to estimate probability of strength maintenance in the analysed population. Weibull distribution parameters were interpreted as a characteristic material strength (scale parameter) and structural reliability parameter in terms of ability to maintain strength by each of specimen from the general population (shape parameter). 20 composite specimens underwent strength tests, including 2 “flow” type composites and 2 standard composites (with typical filler content). “Flow” type composites were characterized with lower characteristic strength and higher structural reliability comparing to other studied composites.
Acta of bioengineering and biomechanics / Wroclaw University of Technology
In this paper, the results of study of mechanical properties for four commercial polymer-ceramic ... more In this paper, the results of study of mechanical properties for four commercial polymer-ceramic composites applied in the conservative dentistry are presented, including one new silorane based composite and three standard composites based on methacrylate compounds. Influence of the type of light of diode and halogen polymerization lamps on the microhardness, flexural strength and elasticity were studied. Both exposed and unexposed specimens were taken into account. An exposure time was also differentiated (40 sec and 60 sec). Basic statistics of the analysed material parameters were determined. A post hoc test (Newman-Keuls) was performed in order to evaluate differences between microhardness of the materials studied, as well as Kruskal-Wallis test to evaluate differences in flexural strength and elasticity modulus of the material. It has been indicated that there is an impact of the type of lamp on the microhardness and flexural strength of composites with methacrylate matrix and lack of such impact in the case of composites containing siloranes. Additionally, it has been found that an increase of photopolymerization time has a significantly different impact on the mechanical properties depending on the type of irradiated material.
The purpose of this paper was to present a reliability comparison of city transport buses on the ... more The purpose of this paper was to present a reliability comparison of city transport buses on the example of Solaris Urbino 12 and Mercedes- Benz 628 Conecto LF at Municipal Transport Company in Lublin. A reliability index for the most failure parts and complex systems for the period of time up to first damage was determined. It has been demonstrated, that during the operation significant reliability differences occur between the buses produced nowadays.
The paper presents some aspects of operation of municipal transport system in the city of Lublin ... more The paper presents some aspects of operation of municipal transport system in the city of Lublin (Poland). Organization of Lublin Municipal Transport Company was described, its efficiency and perspectives of development. Particular attention was paid to the rules of adjustment to the EU requirements, and to the influence of demographic and social factors. Infrastructure of public transport in Lublin was analyzed (busses, trolley‐busses, bus stations, fixed objects and bus stops), as well as configuration of bus and trolley‐bus lines. Some specific proposals were also put forward regarding development solutions: development plan of trolley‐bus traction, plan of inter‐connection bus station, development plan of bus traction, introduction of advanced IT solutions into the public transport management and natural gas (CNG) fuelling of the city busses. Keywords: urban transport, urban transport problems.
Streszczenie W artykule przeanalizowano niezawodność specjalistycznych zabudów samochodów pożarni... more Streszczenie W artykule przeanalizowano niezawodność specjalistycznych zabudów samochodów pożarniczych użytkowanych przez Państwową Straż Pożarną (PSP). Badania zostały przeprowadzone na próbie 22 średnich samochodów ratowniczo-gaśniczych będących na wyposażeniu jednostek PSP na terenie m.st. Warszawa. Dane do analizy niezawodności zostały pozyskane z Systemu Wspomagania Decyzji-ST Komendy Miejskiej PSP m. st. Warszawa i obejmowały przedział czasu od stycznia 2012 r. do maja 2015 r. Wyniki badań przedstawiają liczbę i czas odnowy niezdatności oraz wartości wskaźników niezawodności podsystemu pożarniczego samochodów ratowniczo-gaśniczych. Wykazano, że jedną z głównych przyczyn niezdatności zabudów specjalistycznych analizowanych samochodów pożarniczych jest uszkodzenie układu wodno-pianowego. Ponadto wykazano niską gotowość techniczną zabudów specjalistycznych średnich samochodów ratowniczo-gaśniczych przeznaczonych do użytkowania podczas w działaniach ratowniczych.
The article presents results of experimental studies on mechanical properties of the polymer-comp... more The article presents results of experimental studies on mechanical properties of the polymer-composite material used in manufacturing firefighting helmets. Conducted studies included static and impact strength tests, as well as a shock absorption test of glass fiber-reinforced polyamide 66 (PA66) samples and firefighting helmets. Samples were subject to the impact of thermal shocks before or during being placed under a mechanical load. A significant influence of thermal shocks on mechanical properties of glass fiber-reinforced PA66 was shown. The decrease in strength and elastic properties after cyclic heat shocks ranged from a few to several dozen percent. The average bending strength and modulus during the 170 degree Celsius shock dropped to several dozen percent from the room temperature strength. Under these thermal conditions, the impact strength was lost, and the lateral deflection of the helmet shells increased by approximately 300%. Moreover, while forcing a thermal shock oc...
With easy-to-process 3D printing materials and fast production, the quality of dental services ca... more With easy-to-process 3D printing materials and fast production, the quality of dental services can be improved. In the conventional procedure, the dentist makes temporary crowns directly in the patient’s mouth, e.g., from the most commonly used bis-acrylic composites. Temporary crowns made directly in the office without the use of CAD/CAM are often of inferior quality, which directly results in impaired hygiene, poorer masticatory mechanics, greater deposition of plaque, calculus and sediment, and may adversely affect periodontal and gum health. The mechanical strength, resistance to aging and abrasion of 3D printing materials are higher than those of the soft materials used in conventional methods. This translates into durability. The patient leaves the surgery with a restoration of higher utility quality compared to the conventional method. The objective of the paper was to determine the influence of aging in artificial saliva of AM (additive manufacturing) orthodontic composites ...
Badania właściwości absorpcyjnych pianek polimerowych stosowanych w krajowej produkcji hełmów strażackich / Studies on Absorptive Properties of Polymer Foams Used for Manufacturing of Firefighter Helmets in Poland
Conditions of firefighting –rescue actions, especially during internal fires are characterized by... more Conditions of firefighting –rescue actions, especially during internal fires are characterized by a number of threats. They mainly come from thermal and mechanical factors. Firefighter’s head is mainly exposed to mechanical threats, protected by a firefighter helmet. The helmet absorbs part of mechanical impact energy in the direction of rescuer. The objective of the study was determination of central forces corresponding to impact energy of 60J and degree of redistribution of forces in a direction of cervical spine. The studies were conducted on the selected helmets at conditions of combined thermal and mechanical exposures (as it occurs in operating conditions). The studies have demonstrated that kinetic energy of impact to the helmet placed on the head is mainly exchanged to strain energy (deformation) of shell, protective insert, and if present a cradle. This process depends on the helmet’s construction. Temperature of thermal exposure impacting helmet is crucial for absorbing a...
The paper deals with the issue of mechanical strength of climbing ropes. These ropes are exposed ... more The paper deals with the issue of mechanical strength of climbing ropes. These ropes are exposed to the influence of exploitation factors both during training and in rescue operations. Among others, they may sustain mechanical, thermal and chemical damage. The study attempted to provide an evaluation of the effect this damage has on the mechanical strength and extensibility of ropes. The tests were carried out in laboratory conditions, and the courses of force in the function of deformation and impact of force on deformation were recorded. An unfavourable influence of some types of damage on the strength and extensibility of ropes was demonstrated. Mechanical and thermal stresses mainly cause damage to the rope sheath. Their effect on endurance is similar. The remaining strength of the rope is slightly above the minimum allowable tensile strength. On the other hand, the chemical treatment did not cause a noticeable decrease in the rope’s strength.
International Journal of Environmental Research and Public Health
Orthodontic retention is the final important stage of orthodontic treatment, the aim of which is ... more Orthodontic retention is the final important stage of orthodontic treatment, the aim of which is to consolidate the functional and aesthetic position of teeth. Among adults, fixed retainers made of different types of wires are the most common. The aim of this study was to analyse the mechanical properties of a new generation of fixed orthodontic retainers—printed by 3D printers. Materials and Methods: The study was conducted using samples made of Nextdent MFH C&B N1 resin in the form of cuboid bars with nominal dimensions of width b = 3 mm, thickness d = 0.8 mm; 1 mm; 1.2 mm, length l = 30 mm for each type. The influence of the thickness of the retainers on their strength under loaded conditions was evaluated. Flexural strength, elastic properties, deflection, and creep were compared. The samples were aged in an artificial saliva bath at 37 ± 1 °C during the strength tests. Results: It was shown that differences in the thickness of the samples affected their elastic and strength pro...
With the constant growth of requirements to the quality of infocommunication services, special at... more With the constant growth of requirements to the quality of infocommunication services, special attention is paid to the management of information transfer in wireless self-organizing networks. The clustering algorithm based on the Motley signal propagation model has been improved, resulting in cluster formation based on the criterion of shortest distance and maximum signal power value. It is shown that the use of the improved clustering algorithm compared to its classical version is more efficient for the route search process. Ant and simulated annealing algorithms are presented to perform route search in a wireless sensor network based on the value of the quality of service parameter. A comprehensive routing method based on finding the global extremum of an ordered random search with node addition/removal is proposed by using the presented ant and simulated annealing algorithms. It is shown that the integration of the proposed clustering and routing solutions can reduce the route s...
The quality and reliability of consumables, including gear oils, results in the failure-free oper... more The quality and reliability of consumables, including gear oils, results in the failure-free operation of the transmission components in heavy trucks. It is known that oil viscosity is essential for all lubricated tribopairs for wear and friction reduction in all vehicles with a gearbox. Viscosity may be influenced by the contamination that wear products can impart on the oil. Oil contamination can also affect lubrication efficiency in the boundary friction conditions in gearboxes where slips occur (including bevel and hypoid gearboxes). The present research focused on this issue. An obvious hypothesis was adopted, where it was theorized that exploiting the contaminants that are present in gear oil may affect how the lubricating properties of gear oils deteriorate. Laboratory tests were performed on contaminants that are commonly found in gear oil using the Parker Laser CM20. The study was designed to identify a number of different solid particles that are present in oil. At the sec...
In the article the application of Bayesian probabilistic modeling was presented as a way to stand... more In the article the application of Bayesian probabilistic modeling was presented as a way to standardize analytics of measurement results, which completes the operational and procedural standardization of determining the strength of dental composites. The traditional way of conducting studies of strength performed as services and calculations, and which do not refer to previous studies, was changed into an adaptation process of knowledge accumulation in a form of an increasing precise models. Probabilistic flexural strength models were used to create a reliability ranking of studied dental composites. Conceptualization of reliability of a biotechnological system, such as a “tooth-dental composite” required the expansion of the notion of“failure” with random events involving the occurrence of compatibility failure.
The aim of the study was to compare microhardness and wear resistance of ceramic-polymer composit... more The aim of the study was to compare microhardness and wear resistance of ceramic-polymer composites with micro and nano-hybrid structure. For the studies commercial composites were used, containing filler particles of the same type but different sizes, nano-sized (Filtek Ultimate) and micro-sized (Filtek Z250) composites. Tribological testing was conducted using ball-on-disc micro-tribometer. Vickers testing method was applied for microhardness studies with the use of Futertech FM 700 device. It has been demonstrated that the wear of Filtek Ultimate is almost twice lower in comparison to wear of Filtek Z250 composite. It has been concluded that the use of filler nanoparticles significantly increased wear resistance of the material. Additionally, lack of correlation between material microhardness and wear resistance has been demonstrated.
The paper presents analysis of the availability of medium firefighting and rescue vehicles chassi... more The paper presents analysis of the availability of medium firefighting and rescue vehicles chassis used by State Fire Brigade in Warsaw. For analysis of availability of vehicles chassis the technical availability factor has been used. Additionally, in the paper time to restore of the vehicles chassis regarding causes of unavailability has been presented. In the tests the data obtained from the Decision Support System (DSS) of Warsaw State Fire Brigade were applied. The research included the period from January 2012 to May 2015. Based on the results, it can be statement that the operating mileage is the crucial factor of operating degradation of firefighting vehicles chassis.
In this paper the reliability assessment of structural reliability of the selected light-cured de... more In this paper the reliability assessment of structural reliability of the selected light-cured dental composites based on the biaxial flexural strength test results has been presented. A two-parameter Weibull distribution was applied as a reliability model in order to estimate probability of strength maintenance in the analysed population. Weibull distribution parameters were interpreted as a characteristic material strength (scale parameter) and structural reliability parameter in terms of ability to maintain strength by each of specimen from the general population (shape parameter). 20 composite specimens underwent strength tests, including 2 “flow” type composites and 2 standard composites (with typical filler content). “Flow” type composites were characterized with lower characteristic strength and higher structural reliability comparing to other studied composites.
Acta of bioengineering and biomechanics / Wroclaw University of Technology
In this paper, the results of study of mechanical properties for four commercial polymer-ceramic ... more In this paper, the results of study of mechanical properties for four commercial polymer-ceramic composites applied in the conservative dentistry are presented, including one new silorane based composite and three standard composites based on methacrylate compounds. Influence of the type of light of diode and halogen polymerization lamps on the microhardness, flexural strength and elasticity were studied. Both exposed and unexposed specimens were taken into account. An exposure time was also differentiated (40 sec and 60 sec). Basic statistics of the analysed material parameters were determined. A post hoc test (Newman-Keuls) was performed in order to evaluate differences between microhardness of the materials studied, as well as Kruskal-Wallis test to evaluate differences in flexural strength and elasticity modulus of the material. It has been indicated that there is an impact of the type of lamp on the microhardness and flexural strength of composites with methacrylate matrix and lack of such impact in the case of composites containing siloranes. Additionally, it has been found that an increase of photopolymerization time has a significantly different impact on the mechanical properties depending on the type of irradiated material.
The purpose of this paper was to present a reliability comparison of city transport buses on the ... more The purpose of this paper was to present a reliability comparison of city transport buses on the example of Solaris Urbino 12 and Mercedes- Benz 628 Conecto LF at Municipal Transport Company in Lublin. A reliability index for the most failure parts and complex systems for the period of time up to first damage was determined. It has been demonstrated, that during the operation significant reliability differences occur between the buses produced nowadays.
The paper presents some aspects of operation of municipal transport system in the city of Lublin ... more The paper presents some aspects of operation of municipal transport system in the city of Lublin (Poland). Organization of Lublin Municipal Transport Company was described, its efficiency and perspectives of development. Particular attention was paid to the rules of adjustment to the EU requirements, and to the influence of demographic and social factors. Infrastructure of public transport in Lublin was analyzed (busses, trolley‐busses, bus stations, fixed objects and bus stops), as well as configuration of bus and trolley‐bus lines. Some specific proposals were also put forward regarding development solutions: development plan of trolley‐bus traction, plan of inter‐connection bus station, development plan of bus traction, introduction of advanced IT solutions into the public transport management and natural gas (CNG) fuelling of the city busses. Keywords: urban transport, urban transport problems.
Streszczenie W artykule przeanalizowano niezawodność specjalistycznych zabudów samochodów pożarni... more Streszczenie W artykule przeanalizowano niezawodność specjalistycznych zabudów samochodów pożarniczych użytkowanych przez Państwową Straż Pożarną (PSP). Badania zostały przeprowadzone na próbie 22 średnich samochodów ratowniczo-gaśniczych będących na wyposażeniu jednostek PSP na terenie m.st. Warszawa. Dane do analizy niezawodności zostały pozyskane z Systemu Wspomagania Decyzji-ST Komendy Miejskiej PSP m. st. Warszawa i obejmowały przedział czasu od stycznia 2012 r. do maja 2015 r. Wyniki badań przedstawiają liczbę i czas odnowy niezdatności oraz wartości wskaźników niezawodności podsystemu pożarniczego samochodów ratowniczo-gaśniczych. Wykazano, że jedną z głównych przyczyn niezdatności zabudów specjalistycznych analizowanych samochodów pożarniczych jest uszkodzenie układu wodno-pianowego. Ponadto wykazano niską gotowość techniczną zabudów specjalistycznych średnich samochodów ratowniczo-gaśniczych przeznaczonych do użytkowania podczas w działaniach ratowniczych.
The article presents results of experimental studies on mechanical properties of the polymer-comp... more The article presents results of experimental studies on mechanical properties of the polymer-composite material used in manufacturing firefighting helmets. Conducted studies included static and impact strength tests, as well as a shock absorption test of glass fiber-reinforced polyamide 66 (PA66) samples and firefighting helmets. Samples were subject to the impact of thermal shocks before or during being placed under a mechanical load. A significant influence of thermal shocks on mechanical properties of glass fiber-reinforced PA66 was shown. The decrease in strength and elastic properties after cyclic heat shocks ranged from a few to several dozen percent. The average bending strength and modulus during the 170 degree Celsius shock dropped to several dozen percent from the room temperature strength. Under these thermal conditions, the impact strength was lost, and the lateral deflection of the helmet shells increased by approximately 300%. Moreover, while forcing a thermal shock oc...
With easy-to-process 3D printing materials and fast production, the quality of dental services ca... more With easy-to-process 3D printing materials and fast production, the quality of dental services can be improved. In the conventional procedure, the dentist makes temporary crowns directly in the patient’s mouth, e.g., from the most commonly used bis-acrylic composites. Temporary crowns made directly in the office without the use of CAD/CAM are often of inferior quality, which directly results in impaired hygiene, poorer masticatory mechanics, greater deposition of plaque, calculus and sediment, and may adversely affect periodontal and gum health. The mechanical strength, resistance to aging and abrasion of 3D printing materials are higher than those of the soft materials used in conventional methods. This translates into durability. The patient leaves the surgery with a restoration of higher utility quality compared to the conventional method. The objective of the paper was to determine the influence of aging in artificial saliva of AM (additive manufacturing) orthodontic composites ...
Badania właściwości absorpcyjnych pianek polimerowych stosowanych w krajowej produkcji hełmów strażackich / Studies on Absorptive Properties of Polymer Foams Used for Manufacturing of Firefighter Helmets in Poland
Conditions of firefighting –rescue actions, especially during internal fires are characterized by... more Conditions of firefighting –rescue actions, especially during internal fires are characterized by a number of threats. They mainly come from thermal and mechanical factors. Firefighter’s head is mainly exposed to mechanical threats, protected by a firefighter helmet. The helmet absorbs part of mechanical impact energy in the direction of rescuer. The objective of the study was determination of central forces corresponding to impact energy of 60J and degree of redistribution of forces in a direction of cervical spine. The studies were conducted on the selected helmets at conditions of combined thermal and mechanical exposures (as it occurs in operating conditions). The studies have demonstrated that kinetic energy of impact to the helmet placed on the head is mainly exchanged to strain energy (deformation) of shell, protective insert, and if present a cradle. This process depends on the helmet’s construction. Temperature of thermal exposure impacting helmet is crucial for absorbing a...
Uploads
Papers by Daniel Pieniak