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Tytuł:
High-speed optical methane concentration meter with the dust compensation of mine atmosphere
Optyczny miernik stężenia metanu o dużej prędkości z kompensacją pyłu w atmosferze kopalnianej
Autorzy:
Vovna, A.
Zori, A.
Kostenko, V.
Verhovsky, YA.
Kostenko, T.
Powiązania:
https://bibliotekanauki.pl/articles/1361178.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
miernik
wydajność prędkości
kompensacja multiplikatywna
charakterystyki konwersji
testy
meter
speed performance
multiplicative compensation
conversion characteristics
tests
Opis:
We tested an optical-absorption methane concentration meter for coal mines conditions. We studied conversion characteristics and evaluated its speed performance and proposed a method of dusty coal mines air multiplicative compensation. Requirements to the development of a methane concentration meter are provided.
Przedstawiono realizację testów optyczno-absorpcyjny miernik stężenia metanu do użytku w warunkach kopalnianych. Zbadano charakterystyki konwersji i dokonano oceny wydajności prędkości. Następnie zaproponowano metodę multiplikatywnej kompensacji zapylonej atmosfery kopalnianej. Przedstawiono też wymagania dotyczące miernika stężenia metanu.
Źródło:
Mining – Informatics, Automation and Electrical Engineering; 2015, 53, 2; 28-34
2450-7326
2449-6421
Pojawia się w:
Mining – Informatics, Automation and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the influence of hydraulic oil temperature on the variable-speed pump performance
Autorzy:
Stawiński, Łukasz
Kosucki, Andrzej
Cebulak, Maciej
Górniak vel Górski, Adrian
Grala, Mikołaj
Powiązania:
https://bibliotekanauki.pl/articles/2087011.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
hydraulic pump
volumetric efficiency
temperature-dependent characteristics
variable speed drive
hydraulic oil
Opis:
This paper describes investigation on the influence of hydraulic oil temperature on the performance of a hydraulic pump. The aim of the research is to determine changes in volumetric efficiency of the pump in the form of maps of operation at different temperatures of the hydraulic oil, in conditions of variable speed and pressure. The described tests were carried out on an experimental stand with a hydraulic fixed-displacement gear pump controlled by a servo motor. Based on the signals from the sensors processed with the LabVIEW program, maps of the hydraulic pump operation were drown in a wide range of speeds and temperatures. The paper presents the results of the research and based on this the conclusions regarding the main aim of the research and others that were observed during the measurements were presented. The most important conclusion from the study shows that the temperature-dependent characteristics provide users with a significant amount of information such as operating conditions that will ensure a high level of efficiency.
Źródło:
Eksploatacja i Niezawodność; 2022, 24, 2; 289--296
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the influence of rotational speed on the performance of high-speed permanent-magnet generator
Autorzy:
Qiu, Hongbo
Wei, Yanqi
Zhao, Xi Fang
Yang, Cunxiang
Yi, Ran
Powiązania:
https://bibliotekanauki.pl/articles/141641.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high-speed permanent-magnet generator (HSPMG)
harmonic content
maximum power
overload capacity
voltage regulation
Opis:
When the machine is at high speed, serious problems occur, such as high frequency loss, difficult thermal management, and the rotor structural strength insufficiency. In this paper, the performances of two high-speed permanent magnet generators (HSPMGs) with different rotational speeds and the same torque are compared and analyzed. The two-dimensional finite element model (FEM) of the 117 kW, 60 000 rpm HSPMG is established. By comparing a calculation result and test data, the accuracy of the model is verified. On this basis, the 40 kW, 20 000 rpm HSPMG is designed and the FEM is established. The relationship between the voltage regulation sensitivity and power factor of the two HSPMGs is determined. The influence mechanism of the voltage regulation sensitivity is further revealed. In addition, the air-gap flux density is decomposed by the Fourier transform principle, and the influence degree of different harmonic orders on the HSPMG performance is determined. The method to reduce the harmonic content is further proposed. Finally, the method to improve the HSPMG overload capacity is obtained by studying the maximum power. The research showed that the HSPMG at low speed (20 000 rpm) has high sensitivity of the voltage regulation, while the HSPMG at high speed (60 000 rpm) is superior to the HSPMG at low speed in reducing the harmonic content and increasing the overload capacity.
Źródło:
Archives of Electrical Engineering; 2019, 68, 1; 77-90
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Equivalence Ratio and Mean Piston Speed on Performance of an Irreversible Dual Cycle
Autorzy:
Ebrahimi, R.
Powiązania:
https://bibliotekanauki.pl/articles/1493377.pdf
Data publikacji:
2011-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Ln
82.60.Fa
88.05.-b
Opis:
In the present study, the performance of an air standard dual cycle is analyzed using finite-time thermodynamics. The relations between the power output and the compression ratio, between the power output and the thermal efficiency are derived by detailed numerical examples. The results show that the maximum power output and the power output at the maximum efficiency point increase and then decrease as the equivalence ratio and/or the mean piston speed increases. The results also show that the optimal compression ratio corresponding to maximum power output point and the working range of the cycle remain constant as the mean engine speed is increased, but they increase and then decrease as the equivalence ratio is increased. It is noteworthy that the results obtained in the present study are of significance for providing guidance with respect to the performance evaluation of practical internal combustion engines.
Źródło:
Acta Physica Polonica A; 2011, 120, 3; 384-389
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Impact of Entrepreneurial Orientation on the Performance and Speed of Internationalization
Autorzy:
Freiling, Jörg
Lütke Schelhowe, Christoph
Powiązania:
https://bibliotekanauki.pl/articles/474884.pdf
Data publikacji:
2014
Wydawca:
Fundacja Upowszechniająca Wiedzę i Naukę Cognitione
Tematy:
entrepreneurial orientation
entrepreneurial functions
international performance
international growth
exploration
exploitation
Opis:
Entrepreneurial orientation has emerged as a major construct in entrepreneurship literature. However, existing definitions of entrepreneurial orientation mainly focus on explorative behavior like innovativeness, proactiveness and risk-taking. Based on the long tradition of research on entrepreneurial functions, we argue that exploitative activities are no less an entrepreneurial endeavor than explorative activities. Following this understanding, we elaborate a broader conceptualization of the entrepreneurial orientation construct. In an empirical study with 346 established companies, we explore its effect on the performance of internationalization. Entrepreneurial orientation in its broader conceptualization positively influences the international performance and the effect is by far stronger than the one observed in existing studies. The reason for this is that both explorative and exploitative dimensions matter and equally drive the international performance. Entrepreneurial orientation positively influences the growth of the international activities as well. However, its effect is much lower. Whereas the explorative dimensions tend to foster the international growth, the exploitative dimensions do not show any effect.
Źródło:
Journal of Entrepreneurship, Management and Innovation; 2014, 10, 4; 169- 199
2299-7075
2299-7326
Pojawia się w:
Journal of Entrepreneurship, Management and Innovation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Criteria of athlete neuromuscular system reserve capacities during performance of speed-strength work
Autorzy:
Pryimakov, Oleksandr
Jashchanin, Jan
Shchegolkov, Aleksandr
Powiązania:
https://bibliotekanauki.pl/articles/1055170.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
athletes
efforts
electric activity of muscles
fatigue
jumps
work capacity
Opis:
The work presents complex methods of simultaneous registration of electric activity of the lower extremity muscles and efforts developed in the process of jumping test performance to exhaustion with revealing structural changes of muscles, their capillaries and other energy supply elements. Methodology reveals inborn predisposition of the system of execution and management of locomotion to loads of different character as well as the level of neuromuscular system reserve capacities in the process of long-term adaptation to physical loads.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2014, 6, 2; 35-43
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-performance high-speed WIM for sustainable road load monitoring using GIS technology
Autorzy:
Kim, Jong Woo
Jung, Young Woo
Utebayeva, Ainura
Kamaliyeva, Zhuldyz
Collins, Neil
Sarbassov, Dastan
Sagin, Janay
Amanzhlova, Raushan
Powiązania:
https://bibliotekanauki.pl/articles/2098176.pdf
Data publikacji:
2021
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
WIM
weight-in-motion
silk road
one belt
KAIA
ważenie pojazdów w ruchu
jedwabny szlak
jeden pas
Opis:
The increasing importance of better transport connectivity has indicated the need to develop high-speed road load monitoring technologies. The Belt and Road Initiative (BRI), Silk Road transportation programs considerable have developed the roads and highways networks in Kazakhstan and other Central Asian (CA) countries. Transportation services require proper maintenance and prompt track load monitoring. There is no holistic freight traffic management system that controls and monitors traffic flow in CA. A Weigh in Motion (WIM) technology can be used as an effective traffic management control system in the CA region. The WIM technology is designed to control axle and gross vehicle weight in motion. It has a wide range of applications, including pavement and bridge weight control, traffic legislation and state regulations. The WIM technology has advantages over conventional static weighing as it does not interrupt traffic flow by creating queues at monitoring stations. The WIM technology can be used not only as a weight control tool but also performs a comprehensive analysis of other traffic flow parameters. In cooperation with Korean UDNS experts with suport from KAIA, we test the application of WIM in Nur-Sultan city, North of Kazakhstan, with Siberian-type cold weather. These works create much challenges and innovative approach to test sensors in the harsh environment, from the extreme cold to hot temperatures, with intensive dust distortions. Our Talapker WIM pilot test site was installed in September 2020, and it performs Gross Vehicle Weight (GVW) and Axle of Weight (AOW) analyses. The Talapker WIM High Speed (HS) sensors are capable of detecting different driving patterns, including everyday driving, acceleration or deceleration more than 10km/h/s and eccentric driving (partial contact with the platform to avoid excessive weighting). The pilot Talapker HS WIM site has demonstrated a positive effect on implementing WIM technology in Kazakhstan. Every 10th car passing through the WIM site registered as an overloaded vehicle by gross weighting, and every 5th car is considered overloaded by axle weighting. GIS-based location allocation analysis (LAA) performed in the given study provided an understanding of a practical implementation of WIM sensors. Taking into consideration different geographical data, the WIM site map was developed to reveal 43 suitable locations. Further improvements for the CA road network and their WIM demand points will be the focus of future research investigations.
Źródło:
Transport Problems; 2021, 16, 4; 149--162
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Test research on the resistance performance of high-speed trimaran planing hull
Autorzy:
Ma, W.
Sun, H.
Zou, J.
Yang, H.
Powiązania:
https://bibliotekanauki.pl/articles/259708.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
trimaran planing hull
side hulls
high speed
step
resistance
model test
Opis:
In order to identify high-speed navigation ability of trimaran planing hull, as well as investigate the characteristics of its resistance and hull form, ship model tests were conducted to measure resistance, trim and heaving under different displacements and gravity centre locations. The test results were then used to study the influence of spray strips on resistance and sea-keeping qualities. Moreover, different planning surfaces were compared in the model tests which helped to look into influence of steps on hull resistance and its moving position. Also, the resistance features of monohull and trimaran planing hulls, both with and without steps, were compared to each other. From the tests it can be concluded that: the two auxiliary side hulls increase aerodynamic lift at high-speed motion, which improves the hydrodynamic performance; the trimaran planing hull has also excellent longitudinal stability and low wave-making action; when Fr∇> 8, its motion is still stable and two distinct resistance peaks and two changes of sailing state (the second change is smaller) appear; spray strips are favourable for sea-keeping qualities at high speed. The change trends before the second resistance peak as to the resistance and sailing behaviour of trimaran planing hull without steps are the same as for monohull planing hull without steps. but when steps in both hulls exist the change trends are different; more specifically: trimaran planing hull with steps has only one resistance peak and its resistance increases along with its speed increasing, and the resistance is improved at the increasing speed as the number of steps increases.
Źródło:
Polish Maritime Research; 2013, 4; 45-51
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seasonal variation of speed, agility and power performance in elite female soccer players: effect of functional fitness
Autorzy:
Stepinski, Miłosz
Ceylan, Halil Ibrahim
Zwierko, Teresa
Powiązania:
https://bibliotekanauki.pl/articles/1921950.pdf
Data publikacji:
2020-02-12
Wydawca:
PPHU Projack Jacek Wąsik
Tematy:
functional performance assessment
physical performance examination
Women's soccer
Opis:
The purpose of this study was to evaluate the changes of speed, agility and power performance during one soccer season and the impact of functional fitness on changes in motor performance in elite female soccer players. This study was conducted with 18 members of the Polish Women's National Football Team. The analyzed training season was divided into four training phases. Physical performance was assessed by a test of quickness - the 5m sprint, tests of maximal speed - the 30 m sprint, test of agility L-run test and tests of lower limb explosive power - counter movement jump (CMJ) and counter movement jump with arm swing. Functional fitness was assessed using the Functional Movement Screen (FMS). Individual functional training as well as a training plan based on FIFA 11+ prevention were utilized. The analysis showed significant improvement in the CMJ test (F=3.02, p<0.05) and FMS score (F=5.959, p<0.01) during the in-season. Other parameters of physical performance were stable during the evaluation period. Positive correlations between baseline FMS score and changes of athletes' 30m sprint performance (r=-0.48, p<0.05), total in-season change of FMS score and total inseason change of 5m sprint performance (r=-0.53, p<0.05) were observed. Female soccer players during the in-season demonstrated a relatively good level of physical performance which corresponds to their particular training phase. Functional fitness intervention appears to be an effective way of improving speed, acceleration, and power performance in elite female soccer players.
Źródło:
Physical Activity Review; 2020, 1, 8; 16-25
2300-5076
Pojawia się w:
Physical Activity Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An experimental study of interceptor’s effectiveness on hydrodynamic performance of high-speed planing crafts
Autorzy:
Karimi, M. H.
Seif, M. S.
Abbaspoor, M.
Powiązania:
https://bibliotekanauki.pl/articles/258886.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
interceptors
drag reduction
hydrodynamic quality
planing catamaran
mono-hull
Opis:
Trim control mechanisms such as interceptors and trim flaps have been widely used in recent years in highspeed crafts for ride and trim control. In spite of their extensive application, a few studies investigating the impact of interceptors on planing craft performance, have been published. In the present study, the impact of interceptors on planing crafts hydrodynamic quality is investigated through application of an experimental method. Two scaled-down models of high-speed planing mono-hull and catamaran are tested with and without interceptors in calm water at different heights of the interceptors to investigate the effect of interceptors on drag reduction of the models. The first one is a scaled-down model of 11 m planning mono-hull boat and the test was conducted at the towing tank of Sharif University of Technology, Iran. The second one is a scaled-down model of 18 m planing catamaran boat and the test was conducted at the towing tank of Krylov Shipbuilding Research Institute (KSRI), Russia. The experimental results show a remarkable drag reduction of up to 15% for mono-hull model and up to 12% for catamaran model over the wide speed range of the models.
Źródło:
Polish Maritime Research; 2013, 2; 21-29
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the operational performance of high speed permanent magnet generator with controlled rectifier in distributed generation
Autorzy:
Hongbo, Q.
Yanqi, W.
Cunxiang, Y.
Kaiqiang, H.
Powiązania:
https://bibliotekanauki.pl/articles/140696.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high speed permanent magnet generator
controlled rectifier
electromagnetic field
switching frequency
Opis:
The uncontrolled rectifier and controlled rectifier which use fixed switching frequency control strategy are applied usually during the working of a high-power high- speed permanent magnet generator (HSPMG). Even for the controlled rectifier, it will generate harmonics. The electromagnetic performance of the HSPMG is also affected by these harmonics. In this paper, the influences of the fixed switching frequency control strategy on a HSPMG were studied. Based on the Fourier theory, the harmonic currents of the generator were analyzed, and the change of harmonic distribution range and current total harmonic distortion (THD) were obtained. By using an indirect field-circuit coupling method, the influences of the fixed switching frequency control strategy on the losses and torque of the generator were analyzed. The relations between the switching frequency and the losses and torque of the generator were obtained, and the change mechanism of the loss was revealed. The obtained conclusions can provide reference for the optimized choice of the switching frequency of the distributed generation system with the HSPMG. It can also provide support for the HSPMG electromagnetic structural optimization and the optimization of the loss and harmonic on the system level.
Źródło:
Archives of Electrical Engineering; 2018, 67, 4; 899-913
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of changes in depth of cut and cutting speed of CNC toolpaths on turning process performance
Autorzy:
Jarosz, K.
Niesłony, P.
Löschner, P.
Powiązania:
https://bibliotekanauki.pl/articles/94112.pdf
Data publikacji:
2018
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
cutting speed
depth of cut
CNC
cutting force
optimization
prędkość cięcia
głębokość cięcia
siła cięcia
optymalizacja
Opis:
In this article, a novel approach to computer optimization of CNC toolpaths by adjustment of cutting speed vcand depth of cut apis presented. Available software works by the principle of adjusting feed rate on the basis of calculations and numerical simulation of the machining process. The authors wish to expand upon this approach by proposing toolpath optimization by altering two other basic process parameters. Intricacies and problems related totheadjustment of apand vcwere explained in the introductory part. Simulation of different variant of the same turning process with different parameter values were conducted to evaluate the effect of changes in depth of cut and cutting speed on process performance. Obtained results were investigated on the account of cutting force and tool life. The authors have found that depth of cut substantially affects cutting force, while the effect of cutting speed on it is minimal. An increase in both depth of cut and cutting speed affects tool life negatively, although the impact of cutting speed is much more severe. An increase in depth of cut allows for a more significant reduction of machining time, while affecting tool life less negatively. On the other hand, the adjustment of cutting speed helpsto reduce machining time without increasing cutting force component values and spindle load.
Źródło:
Archives of Mechanical Technology and Materials; 2018, 38; 40-44
2450-9469
Pojawia się w:
Archives of Mechanical Technology and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Speed Targeted Minimization of Finite State Machines for CPLDs
Autorzy:
Klimowicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/114138.pdf
Data publikacji:
2018
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
finite state machines
minimization
logic synthesis
performance
speed
Opis:
A method of the minimization finite state machines (FSM) is proposed. In this method, such optimization criterion as the critical delay path is taken into account already at the stage of minimizing internal states. The method is based on sequential merging of two internal states including the optimization criteria. The critical path is estimated for CPLD devices. In addition, the proposed method allows one to minimize the number of transitions and input variables of the FSM. Experimental results shows, that the maximum clock frequency of minimized FSMs is higher by 17% comparing to initial FSM.
Źródło:
Measurement Automation Monitoring; 2018, 64, 1; 5-7
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variable rotational speed control system of sewage pumping station
Autorzy:
Szychta, E.
Szychta, L.
Powiązania:
https://bibliotekanauki.pl/articles/116993.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
hydrodynamics
speed control
speed control system
pumping station
sewage pumping station
pump efficiency
control sysytem
pump performance chart
Opis:
Cascade and variable rotational speed control systems of sewage pumping stations are compared in this article. The range of pump efficiency variations and potential for breakdowns are adopted as criteria. A pumping station including two or three pumps is analysed. A control system at a variable rotational speed and maximum sewage level is presented. Properties of a cascade control system and a system at a maximum head of sewage are compared using the example of any pump performance chart.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2019, 13, 2; 343-346
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the influence of performance parameters on the super high speed permanent magnet synchronous generator external characteristic
Autorzy:
Qiu, H.
Tang, B.
Yang, C.
Cui, G.
Powiązania:
https://bibliotekanauki.pl/articles/141228.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
external characteristic
influence degree
performance parameters
super high
speed permanent magnet generator
Opis:
Super high speed permanent magnet generators (SHSPMG) usually operate at high frequency. The external characteristic of the SHSPMG under condition of high frequency operation is quite different from that of conventional generators. Therefore, it is necessary to study the external characteristic of the SHSPMG. Based on the finite element method, this paper studied the factors that affect the external characteristic of the SHSPMG. Combining the vector method and the finite element method, the external characteristic of the SHSPMG with the inductive load and the resistance load was studied. The variation law of the generator terminal voltage with the change of the load and current was obtained, and the key factors affecting the external characteristic of the SHSPMG were determined. The influences of the armature resistance, power factor, frequency and permanent magnet performance on the external characteristic of the SHSPMG were studied. The influence mechanism of different parameters on the generator external characteristic was revealed. The influence degree of each factor on the voltage regulation was determined. The conclusions can provide reference for the design and research of the SHSPMG.
Źródło:
Archives of Electrical Engineering; 2018, 67, 1; 179-192
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Performance Manufacturing Development Strategies in Aviation Industry
Autorzy:
Adamski, W.
Powiązania:
https://bibliotekanauki.pl/articles/971248.pdf
Data publikacji:
2009
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
perspective technologies
manufacturing
simulation
High Speed Machining
Opis:
Foresight. as modern planning tool. "Clean Sky" project will effect in creating new technologies, which usage in aviation will improve fast progress of technique. The paper indicates the newest technologies or technologies which will develop in about 25 years. Aircraft industry future technologies for Polish conditions have been discussed. List of perspective technologies for aviation and engineering industry has been described. These technologies may be developed in Poland to increase economy competitiveness. New revolutionary materials for aviation industry have been presented. Machine tool technologies, especially Computer Numerical Control (CNC), High Speed Machining (HSM) have emerged as effective mechanisms in the aerospace, automotive, and die and mould industries. These new technologies are attractive for competitive manufacturing because of their technical advantages, i.e. a significant reduction in lead-time, high product accuracy, and good surface finish. However, HSM not only stimulates advancements in cutting tools and materials, it also demands increasingly sophisticated CAD/CAM software, and powerful CNC controllers that require more supportive technologies. This paper describes the computational requirement and cutting parameters of HSM, look ahead programming and simulation.
Źródło:
Journal of Machine Engineering; 2009, 9, 4; 5-25
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena skuteczności działania ogranicznika prędkości w pojeździe samochodowym
Performance effectiveness evaluation of the speed limiter in a motor vehicle
Autorzy:
Łączyński, J.
Powiązania:
https://bibliotekanauki.pl/articles/310146.pdf
Data publikacji:
2013
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
pojazd samochodowy
ogranicznik prędkości
motor vehicle
speed limiters
Opis:
W referacie zdefiniowano urządzenie zwane ogranicznikiem prędkości znajdujące się w pojeździe oraz przedstawiono aktualne wymagania dotyczące instalowania ogranicznika prędkości w pojazdach samochodowych zgodnie z Dyrektywą 92/6 EWG i Dyrektywą 2002/85 WE. Wymagania podano dla pojazdów samochodowych wyposażonych w urządzenia ograniczające prędkość należące do kategorii M2, M3 i N2. Opisano ogólną zasadę działania ogranicznika prędkości w pojeździe. Przedstawiono ogólne warunki wykonania badań ogranicznika prędkości w pojeździe z wykorzystaniem przyspieszenia pojazdu zgodnie z wymaganiami zawartymi w Regulaminie 89 EKG ONZ, których celem jest ocena skuteczności działania ogranicznika prędkości na podstawie wyznaczonej krzywej prędkości chwilowej pojazdu w funkcji czasu. Podano również warunki badań ogranicznika prędkości zainstalowanego w samochodzie ciężarowym marki RENAULT typu 24 FP kategorii N3 za pomocą urządzenia firmy CORRSYS-DATRON, które zostały przeprowadzone w Instytucie Transportu Samochodowego w Zakładzie Homologacji i Badań Pojazdów. Wykresami zilustrowano zależności prędkości jazdy od czasu uzyskane podczas wykonanych badań. Pracę zakończono analizą wyników badań.
The paper describes a device, called a speed limiter, located in the vehicle and presents the current requirements for installing the speed limiter in motor vehicles in accordance with Directive 92/6 EEC and Directive 2002/85 EC. The requirements are for vehicles equipped with speed limitation devices and belonging to category M2, M3 and N2. General principle of the vehicle speed limiter operation has been described. General conditions for conducting tests of the speed limiter in vehicle using the acceleration of the vehicle in accordance with the requirements of UN-ECE Regulations 89, whose purpose is to evaluate the effectiveness of the speed limiter based on designated vehicle momentary velocity curve as a function of time, have been presented . It also quotes conditions of tests of the speed limiter installed in the RENAULT type 24 FP truck of N3 category using the device's CORRSYS-DATRON, that have been conducted at the Motor Transport Institute‘s Vehicles Type-Approval & Testing Department. The diagrams illustrate relationship between speed and time, obtained during tests. The work has been summed up with the analysis of the tests results.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2013, 14, 3; 761-768
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical calculations of the hydrodynamic performance of the contra-rotating propeller (CRP) for high speed vehicle
Autorzy:
Ghassemi, H.
Taherinasab, M.
Powiązania:
https://bibliotekanauki.pl/articles/259593.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
boundary element method
contra-rotating propeller
high speed vehicle
Opis:
Several different methods have been used to analyze the marine propellers. In this paper a boundary element method (BEM) for modelling steady hydrodynamic performance of a contra-rotating propeller (CRP) has been developed. The potential flow across the front and rear propellers have been considered. By calculating the induced flow, the interaction between two propellers is studied. This method has been applied to a typical CRP. The results are included in the form of the hydrodynamic performance coefficients, total thrust and torques. Numerical calculations indicate that the predicted hydrodynamic performance shows good conformity with experimental results.
Źródło:
Polish Maritime Research; 2013, 2; 13-20
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the Influence of Elastic Compression Pants Elasticity and Movement Speed on Human Joint Protection
Autorzy:
Zhang, Ningfeng
Liu, Chengxia
Powiązania:
https://bibliotekanauki.pl/articles/2200750.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
fabric
movement speed
protective performance
knee joint
3D motion capture
Opis:
The aim of this study was to clarify how human movement speed and pants elasticity affect the athletic performance of knee joint protection by testing pants with different elastic properties: CP1 (tight pants) and CP2&CP3 (elastic compression pants), which reinforce the knee joint. In addition, CS (cotton sport pants) was developed as a control garment. Three subjects wore CP1, CP2, CP3 and CS while running on the treadmill at three kinds of human movement speed. A three-dimensional motion capture instrument was used to capture the three-dimensional trajectory of the marked points of lower limbs. As a result, the influence of the movement speed on the kinematic parameters (AKJ & gait cycle) was more obvious than the fabric elasticity. If elastic pants are worn during running, the change of AKJ will be stable with the increase of speed. When non-elastic pants are worn, the effect is opposite. Not only that, elastic compression pants are efficient in reducing the motion amplitude of the knee joint during the suspension period as far as 41°, making it highly practical in terms of stability. That is, the elastic fabric can protect the joints when the lower limbs are in motion. Moreover, with the increase of speed and elasticity, the elastic pants can reduce the gait cycle by up to 22% compared with non-elastic pants alone. Through the kinematics mechanism of human joints, these findings may translate into an effect on protective performance and a reduction in sport injuries. Therefore, it is necessary to wear elastic pants, especially compression pants, when running at higher speed, as the average gait cycle gradually decreases. This research shows that the knee joint protection functions of elastic compression garments differ according to the level of elasticity and differential movement speed, providing theoretical support for designing and producing elastic compression pants. It also acts as a guide for the research of lower limb joint protection.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 6 (151); 80--90
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Operational problems of 2+1 bypass road sections
Autorzy:
Tracz, M.
Kieć, M.
Powiązania:
https://bibliotekanauki.pl/articles/223969.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bypass
lane road
speed
overtaking
traffic performance
operating
travel speed
obwodnica
pas drogowy
prędkość jazdy
wyprzedzanie
wydajność ruchu
bezpieczeństwo
Opis:
The paper presents several problems of designing trunk-road bypasses of towns, which can be very helpful in improving their traffic performance. Such roads perform supplementary functions to the operation of network of motorways and express-roads constructed in Poland over the last decade. These problems include: selection of the cross section, selection and design of intersections and interchanges on bypasses, safety and traffic operation problems. The authors highlight the advantages of bypasses and point out some errors, which can be seen in the operation stage, basing on research and observation of 8 bypasses. In the paper traffic operation and road safety analyses for Zyrardow bypass are presented. The final part of the paper gives conclusions and recommendations for 2+1 bypass use and design.
Źródło:
Archives of Transport; 2016, 38, 2; 79-89
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance of map applications on mobile devices: case study
Wydajność aplikacji mapowej na urządzeniach mobilnych: studium przypadku
Autorzy:
Król, Karol
Halva, Jozef
Pagáč Mokrá, Alexandra
Powiązania:
https://bibliotekanauki.pl/articles/1429599.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie
Tematy:
website performance
website speed test
loading speed
conversion rate
quality indices
wydajność strony internetowej
test szybkości witryny
prędkość ładowania
współczynnik konwersji
wskaźniki jakości
Opis:
Performance is one of the most important indicators of quality of software. It plays a significant role not only for business websites and apps, but in case of map components and applications, especially for mobile devices. The aim of the paper is to measure performance of map applications on mobile devices. The performance testing was run on a prototype of an interactive map component of the zoom-lens type using selected web applications. Speed Index (measurement unit) reached the value of 1601 milliseconds, and Performance Score obtained the highest possible value (100 units). A high value of Lighthouse Performance Score was also noted (98 units). Study showed that satisfying measurement results of indices in relation to the time of loading of the component in the browser window are associated with a small size of the component. In case of small components, which enhance the functionality of map websites and apps, it is recommended to compress all parts of the component, regardless of the results of the performance tests.
Wydajność jest jednym z najważniejszych wyznaczników jakości oprogramowania. Wydajność ma istotne znaczenie nie tylko dla witryn i aplikacji biznesowych, ale także w przypadku komponentów i aplikacji mapowych, w szczególności na urządzeniach mobilnych. Celem pracy jest pomiar wydajności aplikacji mapowej na urządzeniach mobilnych. Testom wydajności poddano prototyp interaktywnego komponentu mapowego typu „zoom-lens”. Testy przeprowadzono przy pomocy wybranych aplikacji internetowych. Wskaźnik Speed Index (pomiar jednostkowy) osiągnął wartość 1601 milisekund, a wskaźnik Performance Score osiągną największą możliwą wartość (100 jednostek). Odnotowano także dużą wartość wskaźnika Lighthouse Performance Score (98 jednostek). Badania pokazały, że zadowalające wyniki pomiaru wskaźników związanych z czasem wczytywania komponentu w oknie przeglądarki wynikają z niewielkiego rozmiaru komponentu. W przypadku niewielkich komponentów, które rozszerzają funkcjonalność witryn i aplikacji mapowych wskazana jest kompresja wszystkich część składowych komponentu, niezależnie od wyników testów wydajności.
Źródło:
Geomatics, Landmanagement and Landscape; 2020, 3; 55-64
2300-1496
Pojawia się w:
Geomatics, Landmanagement and Landscape
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Approach to Modelling the Ship Performance in Application to Ferry "Stena Baltica"
Autorzy:
Jurdziński, M.
Guze, S.
Powiązania:
https://bibliotekanauki.pl/articles/320801.pdf
Data publikacji:
2010
Wydawca:
Polskie Forum Nawigacyjne
Tematy:
navigation
ships' speed characteristic
Opis:
The paper deals with analysis of ships speed characteristic in open water areas effected by environmental constraints influencing on ship sea keeping parameters in application to ferry "Stena Baltica" operated in the Baltic Sea between Gdynia and Karlskrona harbors.
Źródło:
Annual of Navigation; 2010, 16; 55-66
1640-8632
Pojawia się w:
Annual of Navigation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance Investigation of High-Speed Train OFDM Systems under the Geometry-Based Channel Model
Autorzy:
Do, Viet Ha
Trinh, Thi Huong
Nguyen, Thanh Hai
Powiązania:
https://bibliotekanauki.pl/articles/1844506.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high-speed train systems
geometry-based channel models
OFDM systems
SINR
capacity
Opis:
The high-speed of train (HST) in combination with the high carrier frequency of HST systems leads to the severe inter carrier interference (ICI) in the HST orthogonal frequency division multiplexing (HST-OFDM) systems. To avoid the complexity in OFDM receiver design for ICI eliminations, the OFDM system parameters such as symbol duration, signal bandwidth, and the number of subcarriers should be chosen appropriately. This paper aims to propose a process of HST-OFDM system performance investigation to determine these parameters in order to enhance spectral efficiency and meet a given quality-of-service (QoS) level. The signal-to-interference-plus-noise ratio (SINR) has been used as a figure of merit to analyze the system performance instead of signal-to-noise ratio (SNR) as most of recent research studies. Firstly, using the non-stationary geometry-based stochastic HST channel model, the SINR of each subcarrier has been derived for different speeds of the train, signal bandwidths, and number of subcarriers. Consequently, the system capacity has been formulated as the sum of all the single channel capacity from each sub-carrier. The constraints on designing HST-OFDM system parameters have been thoughtfully analyzed using the obtained expressions of SINR and capacity. Finally, by analyzing the numerical results, the system parameters can be found for the design of HST-OFDM systems under different speeds of train. The proposed process can be used to provide hints to predict performance of HST communication systems before doing further high cost implementations as hardware designs.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 3; 451-457
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transforming Source Code to Mathematical Relations for Performance Evaluation
Autorzy:
Izadkhah, H.
Powiązania:
https://bibliotekanauki.pl/articles/106274.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
Distributed Software Systems
source code
speed up
Discrete Time Markov Chains
Opis:
Assessing software quality attributes (such as performance, reliability, and security) from source code is of the utmost importance. The performance of a software system can be improved by its parallel and distributed execution. The aim of the parallel and distributed execution is to speed up by providing the maximum possible concurrency in executing the distributed segments. It is a well known fact that distributing a program cannot be always caused speeding up the execution of it; in some cases, this distribution can have negative effects on the running time of the program. Therefore, before distributing a source code, it should be specified whether its distribution could cause maximum possible concurrency or not. The existing methods and tools cannot achieve this aim from the source code. In this paper, we propose a mathematical relationship for object oriented programs that statically analyze the program by verifying the type of synchronous and asynchronous calls inside the source code. Then, we model the invocations of the software methods by Discrete Time Markov Chains (DTMC). Using the properties of DTMC and the proposed mathematical relationship, we will determine whether or not the source code can be distributed on homogeneous processors. The experimental results showed that we can specify whether the program is distributable or not, before deploying it on the distributed systems.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica; 2015, 15, 2; 7-13
1732-1360
2083-3628
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance analysis of the speed sensorless induction motor drive with magnetizing reactance estymator
Analiza właściwości bezczujnikowego napędu indukcyjnego z estymatorem reaktancji magnesującej
Autorzy:
Dybkowski, M.
Orłowska-Kowalska, T.
Tarchała, G.
Powiązania:
https://bibliotekanauki.pl/articles/1807699.pdf
Data publikacji:
2011
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
variable speed drives
induction motor
vector control
sensorless control
estimators
Opis:
W artykule przedstawiono wyniki badań bezczujnikowego napędu indukcyjnego z prądowym estymatorem prędkości i strumienia wirnika. Napęd bezczujnikowy został wyposażony w dodatkowy estymator reaktancji magnesującej, wykorzystujący matematyczną interpolację charakterystyki magnesowania silnika. Przeanalizowano właściwości dynamiczne takiego układu napędowego ze sterowaniem wektorowym w szerokim zakresie zmian prędkości zadanej. Przedstawiono wyniki badań symulacyjnych i eksperymentalnych.
Źródło:
Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały; 2011, 65, 31; 147-158
1733-0718
Pojawia się w:
Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały
Dostawca treści:
Biblioteka Nauki
Artykuł
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