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Tytuł:
The implementation of the slice-based transformations in AutoCAD
Realizacja przekształceń opartych na przekrojach w programie AutoCAD
Autorzy:
Koźniewski, E.
Orłowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/118985.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Geometrii i Grafiki Inżynierskiej
Tematy:
twisting
bending
tapering
AutoCAD
skręcanie
gięcie
zbieżność
Opis:
The paper shows how AutoCAD functions can be utilized to perform 3D transformations well-known in literature - i.e. the so called slice-based transformations such as: twisting, bending, tapering, shear transformations to allow automatic modeling of the classic architectural objects, e.g. twisted columns, or Saint Gilles surface.
W pracy pokazano za pomocą jakich funkcji programu AutoCAD można realizować, znane z literatury, przekształcenia oparte na przekrojach, tj. przekształcenia skręcające, ścinające, zginające, zwężające pozwalające automatycznie modelować klasyczne obiekty architektoniczne, takie jak słup skręcony, powierzchnia Saint Gilles.
Źródło:
Journal Biuletyn of Polish Society for Geometry and Engineering Graphics; 2012, 23; 51-56
1644-9363
Pojawia się w:
Journal Biuletyn of Polish Society for Geometry and Engineering Graphics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CO2 narcosis in a COVID-19 patient in prone position due to twisting of reservoir bag of a non-rebreathing mask: a case report
Autorzy:
Kumar, Neeraj
Kumar, Amarjeet
Singh, Prabhat Kumar
Kumar, Sanjeev
Powiązania:
https://bibliotekanauki.pl/articles/29432106.pdf
Data publikacji:
2020
Wydawca:
Towarzystwo Pomocy Doraźnej
Tematy:
COVID-19
Non rebreathing face mask
Twisting
Prone position
Opis:
We know that oxygen therapy plays one of the important role for treating hypoxemia and it is widely used across a whole range of specialties and it involves administration of oxygen at concentrations greater than that in ambient air. We are reporting the first case of twisting of reservoir bag on using non-rebreathing face mask for providing supplemental oxygen in awake prone position in a 60 year old male tested COVID-19 positive. To prevent this twisting we recommend if a manufacturer do slight modification in making of these non-breathing face mask by adding a 1-2 cm L- shaped Plastic connector to the neck end of the oxygen reservoir bag. The sudden deflation of these reservoir bag not only increase the dead space, decrease alveolar ventilation but substantially compromised the gas exchange. So any twisting of these non-rebreathing face mask should be avoided. This twisting may compromise the patient condition due to rapid increase in PaCO2 and detrimental in patients with restrictive airway disease. On keeping the patient in prone position the twisting of the reservoir bag frequently occurs and this simple and useful modification may be beneficial for supplementation of oxygen therapy to COVID-19 patients requiring high fractional inspired oxygen concentration.
Źródło:
Critical Care Innovations; 2020, 3, 4; 30-34
2545-2533
Pojawia się w:
Critical Care Innovations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On a new solution concept for bargaining problems
Autorzy:
Radzik, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1338962.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
twisting
bargaining solution
bargaining problem
average pay-off solution
Opis:
The purpose of this paper is to discuss the properties of a new solution of the 2-person bargaining problem as formulated by Nash, the so-called Average Pay-off solution. This solution of a very simple form has a natural interpretation based on the center of gravity of the feasible set, and it is "more sensitive" to changes of feasible sets than any other standard bargaining solution. It satisfies the standard axioms: Pareto-Optimality, Symmetry, Scale Invariance, Continuity and Twisting. Moreover, it satisfies a new desirable axiom, Equal Area Twisting. It is surprising that no standard solution of bargaining problems has this property. The solution considered can be generalized in a very natural and unique way to n-person bargaining problems.
Źródło:
Applicationes Mathematicae; 1998-1999, 25, 3; 285-294
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Teoreticheskoe issledovanie krutilnykh deformacijj plodonozhki pochatka kukuruzy
Theoretical studies torsional deformations stalk ear of corn
Autorzy:
Rakul, O.
Pilip, V.
Powiązania:
https://bibliotekanauki.pl/articles/78080.pdf
Data publikacji:
2013
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
torsional deformation
corn
stalk
twisting angle
separation process
harvesting
mathematical model
equation
Opis:
In this paper, developed a mathematical model of the process of separation from ears of corn stalks with torsional deformations stalk, which makes it possible to establish patterns of change basic kinematic parameters corn picker multifactor action. Based on the obtained equations the ways of further development of corn-harvesting technical.
Źródło:
Motrol. Motoryzacja i Energetyka Rolnictwa; 2013, 15, 2
1730-8658
Pojawia się w:
Motrol. Motoryzacja i Energetyka Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-performance induction motor drive based on adaptive super-twisting sliding mode control approach
Autorzy:
Farhi, Salah Eddine
Sakri, Djamel
Goléa, Noureddine
Powiązania:
https://bibliotekanauki.pl/articles/2042783.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
barrier function
chattering
gains adaptation
induction motor drive
sliding mode control
super twisting
Opis:
This paper proposes two high-order sliding mode algorithms to achieve highperformance control of induction motor drive. In the first approach, the super-twisting algorithm (STA) is used to reduce the chattering effect and to improve control accuracy. The second approach combines the super-twisting algorithm with a quasi-barrier function technique. While the super-twisting algorithm (STA) aims at the chattering reduction, the Barrier super-twisting algorithm (BSTA) aims to eliminate this phenomenon by providing continuous output control signals. The BSTA is designed to prevent the STA gain from being over-estimated by making these gains to decrease and increase according to system’s uncertainties. Stability and finite-time convergence are guaranteed using Lyapunov’s theory. In addition, the two controlled variables, rotor speed, and rotor flux modulus are estimated based on the second-order sliding mode (SOSM) observer. Finally, simulations are carried out to compare the performance and robustness of two control algorithms without adding the equivalent control. Tests are achieved under external load torque, varying reference speed, and parameter variations.
Źródło:
Archives of Electrical Engineering; 2022, 71, 1; 245-263
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A fatigue testing in complex stress state in the context of problems in the diagnosis and detecting defects in materials of wheels in locomotives
Autorzy:
Czapczyk, K.
Powiązania:
https://bibliotekanauki.pl/articles/241777.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
multiaxial fatigue
bending
twisting
low cycle load
high cycle load
axles of locomotives
Opis:
This paper presents preliminary results of fatigue tests of selected construction materials, which have been exposed to the simultaneous operation of the bending and torsional loads at different mix of these loads. This kind of load generally applies to much responsible construction, especially of machinery for transport. For example, rail transport is one of the most popular measures, which uses different types of locomotives. However, it is no matter what sort of the type of railway vehicle it is, because in each there we can notice a multi-axis load driving axle wheel assemblies. During the technical inspection of these items, ultrasonic flaw detectors are used to detect damage in the material that arose during the exploitation, but are not visible during the external inspection. For this reason, there are many problems, that arise during the diagnostic process using ultrasonic flaw detectors, because it is not always possible to accurately detect the resulting or arising defect in the material axes, especially in some of the built-axes, which can be studied only from the front (on both sides of the mounting of bearings). Taking into account the safety and technical problems in rail transport, it is important to carry out fatigue tests of low- and high-cycles on samples subjected to multiaxial stress state. Initially, there were taken into account the lightweight aluminum (AlMg2Mn0.47Fe0.5) that have been repeatedly multiaxial charged at different percentage of bending and twisting. The results will be referenced to the occurrence of the bending and twisting, as well as to the results obtained with the simultaneous influence of corrosive conditions due to the attempt to make the best possible mapping of the prevailing conditions in which different structural elements must actually work. The load on the low cycle fatigue and high cycle fatigue were chosen after corrosion- stress testing on the same aluminum alloy. In addition, cases of multiaxial fatigue are not as described and explained in detail as the cases of uniaxial fatigue. In spite of this fact, it is necessary to create detailed criterions for multiaxial with low- and high-cycles load.
Źródło:
Journal of KONES; 2012, 19, 4; 149-154
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model Predictive Super-twisting sliding mode control for an autonomous surface vehicle
Autorzy:
Esfahani, Hossein Nejatbakhsh
Szlapczynski, Rafal
Powiązania:
https://bibliotekanauki.pl/articles/260526.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
utonomous Surface Vehicle
Model Predictive Control
Sliding Mode Control
Super-Twisting Algorithm
Chattering Attenuation
Opis:
This paper presents a new robust Model Predictive Control (MPC) algorithm for trajectory tracking of an Autonomous Surface Vehicle (ASV) in presence of the time-varying external disturbances including winds, waves and ocean currents as well as dynamical uncertainties. For fulfilling the robustness property, a sliding mode control-based procedure for designing of MPC and a super-twisting term are adopted. The MPC algorithm has been known as an effective approach for the implementation simplicity and its fast dynamic response. The proposed hybrid controller has been implemented in MATLAB / Simulink environment. The results for the combined Model Predictive Super-Twisting Sliding Mode Control (MP-STSMC) algorithm have shown that it significantly outperforms conventional MPC algorithm in terms of the transient response, robustness and steady state response and presents an effective chattering attenuation in comparison with the Super-Twisting Sliding Mode Control (STSMC) algorithm.
Źródło:
Polish Maritime Research; 2019, 3; 163-171
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The study on the influence of the injected flow swirling on the characteristics of the jet pump
Autorzy:
Panevnyk, D. O.
Powiązania:
https://bibliotekanauki.pl/articles/2201039.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
jet pump
ejection
ejection system
twisting flow
efficiency
pompa strumieniowa
wyrzut
przepływ skrętny
efektywność
Opis:
Purpose: of this paper is to analyze the possibility of increasing the efficiency of wellbore jet pumps by twisting the injected flow. The absence of moving parts, easy transfer of energy, the ability to operate a wide range of performance and low cost have resulted in the use of ejection systems in many oil and gas deposits. The main disadvantage of borehole ejection systems is the insufficient value of the jet pump efficiency. The energy efficiency of downhole jet pumps can be improved by swirling the mixed flows. Design/methodology/approach: To characterize the effect of circulating flows was used an additional factor in the form of the values of the inclination angle of guiding elements that swirl the flow or the rotation frequency of jet pump elements. In the process of determining the values characterizing the operating process of ejection systems, the flow rates of the working and injected flow and the pressure values in front of the nozzle, the receiving chamber and the chamber at the outlet from the diffuser of the jet pump are subject to direct measurement. Swirling of the injected flow was carried out by placing a sleeve with guiding elements, manufactured using 3D printing technology, in the receiving chamber of the jet pump. Findings: The analysis revealed that in the design of downhole jet units, there are used guiding elements, mainly the screw, blade and tangential type, to swirl the flow. A highlighted list of factors that have a direct effect on the flows mixing process. During experimental studies of swirling injected flow type jet pump characteristics, there is obtained an increase in pressure and energy parameters. Research limitations/implications: The task of further research is to determine the characteristics of a downhole swirling injected flow type jet pump for conditions of combined swirling of the working and injected flows. Practical implications: The obtained results make it possible to take into account the presence of guiding elements in the flow path of the jet pump for swirling the flow. Originality/value: It is established that the relationship between the design and technological parameters of the local swirling of the mixed medium is determined by the ratio of rotating and axial components of the flow velocity in the flow path of the jet pump.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2022, 113, 1; 22--30
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza numeryczna nośności stożkowych połączeń wtłaczanych
Numerical analysis of load-carrying capability of conical forced-in joints
Autorzy:
Zimmermanm, J.
Śnieżek, L.
Powiązania:
https://bibliotekanauki.pl/articles/387608.pdf
Data publikacji:
2009
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
analiza numeryczna
nośność
metoda elementów skończonych
skręcanie
numerical analysis
burden
finite element method
twisting
Opis:
Praca dotyczy badań nośności stożkowego połączenia wtłaczanego obciążonego momentem skręcającym za pomocą metody elementów skończonych. Zagadnienie zostało rozwiązane jako przestrzenne, nieliniowe, z uwzględnieniem kontaktu elementów połączenia. Wyniki obliczeń pozwoliły ustalić zależność granicznej wartości momentu skręcającego od osiowej siły wcisku użytej do realizacji połączenia.
The paper concerns the investigation of the conical interference fit joint load capacity subjected to torsion using FEM. The problem has been solved as a three dimensional, nonlinear with contact between joined elements. Using the calculated results, the dependence between the limiting twisting moment and axial interference force, which was used to carry out the connection, was established.
Źródło:
Acta Mechanica et Automatica; 2009, 3, 1; 130-132
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pitch and yaw motion control of 2 DoF helicopter subjected to faults using sliding-mode control
Autorzy:
Raghappriya, M.
Kanthalakshmi, S.
Powiązania:
https://bibliotekanauki.pl/articles/2134893.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fault tolerant control
sliding mode control
reaching law
super-twisting
sensor
actuator faults
component faults
Opis:
This paper presents a fault-tolerant control scheme for a 2 DOF helicopter. The 2 DOF helicopter is a higher-order multi-input multi-output system featuring non-linearity, cross-coupling, and unstable behaviour. The impact of sensor, actuator, and component faults on such highly complex systems is enormous. This work employs sliding mode control, which is based on reaching and super-twisting laws, to handle the problem of fault control. Simulation tests are carried out to show the effectiveness of the algorithms. Various performance metrics are analyzed and the results show SMC based on super-twisting law provides better control with less chattering. The stability of the closed-loop system is mathematically assured, in the presence of faults, which is a key contribution of this research.
Źródło:
Archives of Control Sciences; 2022, 32, 2; 359--381
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Load of the hydrostatic slipper in axial piston pumps
Obciazenie stopek hydrostatycznych maszyn wielotloczkowych osiowych
Autorzy:
Zloto, T.
Kowalski, K.
Powiązania:
https://bibliotekanauki.pl/articles/793539.pdf
Data publikacji:
2011
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
piston pump
hydrostatic slipper
hydraulic piston machine
reliability
twisting moment
working pressure
mathematical relationship
MathCad software
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2011, 11
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frictional Coefficient Change of Groove Surface in Compact Spinning with a Suction Groove
Zmiana współczynnika tarcia powierzchni rowka w przędzeniu kompaktowym z rowkiem ssącym
Autorzy:
Ma, H. C.
Lu, S.
Cheng, L. D.
Hua, Z.
Powiązania:
https://bibliotekanauki.pl/articles/231666.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
suction groove
compact spinning
frictional coefficient
twisting
rowek ssania
przędzenie kompaktowe
współczynnik tarcia
skręcanie
tor przędzenia
Opis:
Compared with conventional ring spinning, compact spinning with a suction groove can reduce hairiness and improve yarn quality, and it has certain advantages to long staple fibre. In this article, we analyse the changing rule of rotational speed and study the change curve of the frictional coefficient in the gathering zone. The results show that the fibre bundles’ rotational speed at each point along the surrounding arc gradually decreases from the maximum to zero in the gathering area, but the rotating speed of the fibre bundles is constant in the suction hole. The angle between the parallel component speed and that at each point is near to a linear change in the no suction hole, with there being no change in the suction hole. The parallel component of the frictional coefficient for each point is a variable in the no suction hole, being constant in the suction hole.
Porównując konwencjonalne przędzenie obrączkowe i przędzenie kompaktowe z zastosowaniem rowka ssącego można stwierdzić, że uzyskuje się polepszenie włochatości przy stosowaniu przędzenia z rowkiem. Analizowano charakterystykę zmiany prędkości i krzywe współczynnika tarcia w strefie zbiorczej. Stwierdzono, że prędkość wirowania wiązek włókien zmniejsza się w każdym punkcie łuku toru przędzy, ale prędkość wirowania wiązek włókien jest stała w rowku ssącym. W artykule poddano szczegółowej analizie prędkości i zachowanie przędzy w poszczególnych punktach toru przędzenia.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 5 (101); 40-42
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discrete-time sliding mode control of linear systems with input saturation
Autorzy:
Veselić, Boban
Milosavljević, Čedomir
Peruničić-Draženović, Branislava
Huseinbegović, Senad
Petronijević, Milutin
Powiązania:
https://bibliotekanauki.pl/articles/330574.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
discrete time sliding mode control
super twisting controller
input saturation
disturbance compensation
sterowanie ślizgowe
nasycenie wejściowe
kompensacja zakłóceń
Opis:
The paper proposes a discrete-time sliding mode controller for single input linear dynamical systems, under requirements of the fast response without overshoot and strong robustness to matched disturbances. The system input saturation is imposed during the design due to inevitable limitations of most actuators. The system disturbances are compensated by employing nonlinear estimation by integrating the signum of the sliding variable. Hence, the proposed control structure may be regarded as a super-twisting-like algorithm. The designed system stability is analyzed as well as the sliding manifold convergence conditions are derived using a discrete-time model of the system in the δ-domain. The results obtained theoretically have been verified by computer simulations.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2020, 30, 3; 517-528
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical model of piston ring sealing in combustion engine
Autorzy:
Koszałka, G.
Guzik, M
Powiązania:
https://bibliotekanauki.pl/articles/258834.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
exhaust gas blow-by
displacements of rings
twisting of rings
oil film
cylinder
piston
ring
mathematical model
lubrication
Opis:
This paper presents a mathematical model of piston-rings-cylinder sealing (TPC) of a combustion engine. The developed model is an itegrated model of gas flow through gaps in TPC unit , displacements and twisting motions of piston rings in ring grooves as well as generation of oil film between ring face surfaces and cylinder liner. Thermal deformations and wear of TPC unit elements as well as heat exchange between flowing gas and surrounding walls , were taken into account in the model. The paper contains descriptions of: assumptions used for developing the model , the model itself, its numerical solution as well as its computer application for carrying out simulation tests.
Źródło:
Polish Maritime Research; 2014, 4; 66-78
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of super-twisting sliding mode controllers in direct field-oriented control system of six-phase induction motor: experimental studies
Autorzy:
Listwan, J.
Powiązania:
https://bibliotekanauki.pl/articles/1193593.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
six-phase squirrel-cage induction motor
direct field-oriented control method
super-twisting sliding mode control
experimental studies
Opis:
This paper presents the direct field-oriented control (DFOC) method of six-phase induction motor with the application of super-twisting sliding mode algorithm. The mathematical model of the six-phase induction motor has been described. The descriptions of the space vector modulation (SVM) method and the super-twisting algorithm have been presented. The DFOC method with super-twisting sliding mode controllers has been described. The experimental studies of the DFOC method with super-twisting controllers have been performed, and the results of these studies are presented and discussed.
Źródło:
Power Electronics and Drives; 2018, 3, 38; 23-34
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
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