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1
Content available Destruction of the Structure of Boiling Emulsions
EN
In this paper we consider the processes of dynamic interaction between the boiling particles of the dispersed phase of the emulsion leading to the large droplet breakup. It is indicated the differences in the consideration of forces that determine the crushing of non-boiling and boiling drops. It is determined the possibility of using the model to define the processes of displacement, deformation or fragmentation of the inclusion of the dispersed phase under the influence of a set of neighboring particles. The proposed method allows us to determine the main energy parameters of the homogenization process by boiling the emulsion.
PL
W tym artykule rozważamy procesy dynamicznej interakcji między wrzącymi cząsteczkami zdyspergowanej fazy emulsji, prowadzące do rozpadu dużych kropel. Wskazano na różnice w uwzględnianiu sił, które determinują kruszenie kropli niewrzących i wrzących. Określono możliwość wykorzystania modelu do zdefiniowania procesów przemieszczenia, deformacji lub fragmentacji włączenia fazy rozproszonej pod wpływem zestawu sąsiednich cząstek. Proponowana metoda pozwala określić główne parametry energetyczne procesu homogenizacji podczas ogrzewania i wrzenia emulsji.
2
Content available remote Magnetic levitation in industrial transport systems
EN
The paper presents a well known idea of using permanent magnets as a source of energy in an industrial transport system (for instance maglev). The idea of this paper is to present computation and simulation for a transport system in 2D space using the Ansys environment. An idea for a system which starts to operate only at the very moment when a worker needs help and is moving a heavy object, and is using it with a minimum amount of energy has become an idea about saving energy. When gravity is eliminated by magnetic fields forces, for moving heavy object, we only need to overcome the moment of inertia. All resistance practically disappears, because there is almost no friction in this system. In the paper the use of magnetic field concentration in Halbach array system for eliminating gravitational forces during a load movement has been presented.
PL
W pracy przedstawiono dobrze znaną ideę wykorzystania magnesów trwałych, jako źródła energii w przemysłowym systemie transportu (na przykład maglev). Ideą tego artykułu jest prezentacja obliczeń i symulacji transportu systemu w przestrzeni 2D za pomocą środowiska Ansys. Pomysł na system, który działa tylko w momencie, gdy pracownik potrzebuje pomocy i porusza ciężkim przedmiotem i używa go przy minimalnej ilości energii, staje się pomysłem oszczędzania energii. Kiedy grawitacja jest eliminowana przez siły pola magnetycznego, do przemieszczania ciężkich obiektów wystarczy jedynie pokonać moment bezwładności. Cały opór praktycznie znika, ponieważ w tym układzie prawie nie ma tarcia. W artykule przedstawiono zastosowanie koncentracji pola magnetycznego w układzie macierzy Halbacha do eliminacji sił grawitacyjnych podczas ruchu ładunku.
PL
W artykule przedstawiono założenia i szczegółowe cele projektu oraz aktualny stan wiedzy i możliwości uzyskania postępu w zapewnieniu spójności pomiarowej w europejskim i światowym przemyśle w zakresie siły statycznej, ciągłej i dynamicznej. Omówiono także zakres uczestnictwa GUM oraz potencjalny wpływ założonych w projekcie przedsięwzięć na środowisko, metrologię i użytkowników. Przedstawiono wzorce GUM o najmniejszej niepewności pomiarowej, na których zostaną wykonane badania siły statycznej i ciągłej.
EN
The article presents the assumptions and detailed objectives of the project as well as the current state of the art and the possibilities of achieving progress in ensuring traceability in European and global industry in the field of static, continuous and dynamic force. The scope of GUM participation and the potential impact of the design assumptions on the environment, metrology and users were also discussed. GUM standards with the lowest measurement uncertainty, on which static and continuous force tests will be performed, are presented.
PL
Projektując stężenia połaciowe poprzeczne [1], zaleca się przyjmować zastępcze obciążenie od imperfekcji geometrycznych dźwigarów dachowych. Obciążenie to można bezpiecznie oszacować [1] przy założeniu stałej na długości elementu stabilizowanego siły ściskającej i imperfekcji w kształcie paraboli o strzałce e0. W pracy, dla różnych kształtów imperfekcji geometrycznych elementów stabilizowanych, wyznaczono obciążenia imperfekcyjne oraz siły w prętach tężnika połaciowego i porównano je z siłami wyznaczonymi wg [1]. Wyniki analiz przedstawiono w tabeli i sformułowano syntetyczne wnioski.
EN
During designing transverse roof bracing, [1] recommends taking into account equivalent stabilizing load from geometrical imperfections of roof girders. This load can be safely estimated [1] assuming a constant compression force along the length of the stabilized element and initial parabolic imperfection with maximum amplitude e0. In the paper, for different shapes of geometrical imperfections of stabilized elements, imperfect loads and forces in the roof bracing were determined and compared with the forces determined according to [1]. The results of the analyzes are presented in the table and synthetic conclusions were formulated.
EN
This study investigates the automotive magnetorheological (MR) shock absorber behaviour in conditions of changing temperature. Its temperature-dependent behaviour was quantified between ambient and maximal operating temperatures of the device. Aspects addressed include the temperature dependence of the control coil resistance in the absorber, the influence of operating current level on control coil temperature and the temperature dependence of the absorber force response and energy dissipation in the system. The results of experiments enabled us to evaluate the mechanical performance of the absorber at varied temperatures.
EN
The article is devoted to solving the fundamental and applied problem of nonlinear structural me-chanics of machines by introducing into the drum two additional stop cylinders with supporting rollers at the end and adjustable length, providing a given elliptical or circular shape of a flexible shell with a smoothly variable geometry in the area of its contact with compacted pavement material. Compaction of soil, gravel and asphalt concrete in the sphere of road is not only an integral part of the technological process of the roadbed, road foundation and surface construction, but it is actually the main operation to ensure their strength, stability and durability. The quality, cost and speed of road construction, the possibility of using fundamentally new technologies, structures and materials is largely determined by the availability of modern road machinery.
EN
This experimental study investigated the effects of a conventional cutting fluid during drilling cylindrical holes on workpiece materials made of the AISI 1040 steel. Drilling responses were compared between dry and wet (in presence of the cutting fluid) cutting conditions with respect to drilling force, roundness deviation and taper of the hole, and chip morphology. High production machining and drilling with high cutting speed, feed, and depth of cut were found to be inherently associated with the generation of a large amount of heat and high cutting temperature. In a dry condition such high cutting temperature not only reduces dimensional accuracy and tool life but also impairs the roundness deviation and taper of the hole. The use of a conventional cutting fluid, in such a situation, was very effective to reduce the cutting temperature. In a dry cutting condition, numerous tool-wears were found on the drill bits. Drilling in such a dry condition seriously affects roundness of the hole, and chip shape and color. Contrastingly, use of a traditional cutting fluid reduced temperature as well as improved roundness and taper of the hole. It also acted as a lubricate at the tool tip–work surface interface. Overall, the conventional cutting fluid enhanced the quality of the machine work and potentially can increase machine life of drill bits.
EN
The main purpose of this research was to analyse the distribution of plantar pressures and foot characteristics during walking between weeks 27 and 36 of pregnancy. The secondary purpose was to test the effect of the customized orthopaedic shoes that were worn by the experimental group. Methods: Pregnant women (n = 73) were divided into 2 groups, control group (n = 38) and experimental group (n = 35) which completed 5 gait trials on a walkway (1.55m) at a self-selected velocity of gait, where force, pressure and remaining foot characteristics were sampled and displayed by Novel database pro m (version 25.3.24). Results: Analysis of foot characteristics did not reveal important changes. Analysis of the distribution of plantar pressures revealed few changes in the pre- and post-measurement of the experimental and control groups between weeks 27 and 36 of pregnancy. In the last measurement, there is a significant increase of peak pressure only in the midfoot area of the left foot (151.1 ± 41.2 kPa) and in the hindfoot area of the right foot (346.3 ± 104.1) of the experimental group. The control group exhibits similar pressure development for both of foot. Conclusions: Monitored parameters demonstrated in certain areas notably development of force and contact area. Results of foot characteristics did not reveal a significant changes. As both groups registered similar values in certain areas in a comparison of pre/post measurement characteristics, the influence of specific orthopaedic shoes cannot be conclusively demonstrated in the experimental group.
EN
In the case of bucket wheel excavators, the cutting process is influenced by the forces opposing the working elements and cutting tools. These forces determine the choice of machines and their parameters as well as the operating method [1, 2]. Studies conducted on the failure causes of mechanical parts show that the cutting and loading systems cause the highest rate of failure – about 32% of all recorded mechanical failures [3]. In this paper, we will use the Finite Element Method (FEM) to analyze the deformations and stresses acting on the cutting teeth mounted on the rotor of BWEs. For this, Solid- Works® software was used, both as a CAD tool to design the teeth as well as to model and simulate the phenomena.
EN
This study investigates the behaviour of MR fluids in the oscillatory compression squeeze mode. Experiments were performed on commercially available MR fluids in the purpose-built experimental set-up. The influence of MR fluid’s properties and magnetic flux density on the force generated during the squeeze mode was investigated.
11
EN
According to the scaling laws for nanomechanical resonators, many of their metrological properties improve when downscaled. This fact encourages for constant miniaturization of MEMS/NEMS based sensors. It is a well known fact, that the laws of classical physics cannot be used to describe the systems which are arbitrarily small. In consequence, the classical description of nanoresonators must break down for sufficiently small and cool systems and then the quantum effects cannot be neglected. One of the fundamental question which arises is, how one may investigate quantum effects in MEMS/NEMS sensors and what is the influence of quantum effects on the performance of such systems. In this paper we would like to raise those issues by presenting the results of our work related to our estimations and calculations of MEMS/NEMS dynamics. The first and second sections are of theoretical character. In the first section (Classical modeling), we describe the classical methods for describing the resonator dynamics and the classical limit on the resolution of MEMS/NEMS based force sensors, which is set by the thermomechanical noise. In the second section (Quantum aspects), we concentrate on the quantum description of micro and nanoresonators and the influence of quantum effects, such as zero-point motion and back-action, on their performance (quantum limits). The third section is devoted to the presentation of our experimental methods of MEMS/NEMS deflection metrology, i.e. Optical Beam Deflection method (OBD) and fibre optics interferometry.
12
Content available remote Badania doświadczalne sił w rozporach głębokiego wykopu
PL
W artykule przedstawiono wyniki pomiarów sił w rozporach głębokiego wykopu oraz ich analizę i porównanie z wartościami obliczonymi w projekcie zabezpieczenia. Wykorzystano inżynierski system pomiarowy złożony z oprogramowania i jednostki pomiarowej współpracującej z układem sensorów. Jako czujniki zastosowano mostki tensometryczne naklejane na odpowiednio przygotowaną powierzchnię rozpór wykopu. Obserwowano różne etapy pracy obudowy wykopu w zależności od stanu robót ziemnych oraz odpowiadających im oddziaływań. Zastosowanie częściowych współczynników bezpieczeństwa typowych normowych parć na ściankę szczelną zapewniło bezpieczne zaprojektowanie rozpór wykopu.
EN
The article presents the results of measurements of forces in the struts of deep excavation and the analysis and comparison with values calculated in the project. Engineering measurement system consisting of software, measuring unit, which operates together with the strain gauges was used. Strain gauges were glued to the prepared surface of the struts of the sheet pile. Measurements take into consideration different stages of earthworks and the corresponding loading. The use of partial safety factors for typical earth pressure of code on the wall ensured safe design struts excavation.
EN
In this article, a new mathematical representation of the sinusoidal alternating velocity, force and power by means of some complex quantities, termed ‘holors’ is proposed. The word holor is a term to describe a mathematical entity that is made up of one or more independent quantities, and includes complex numbers, scalars, vectors, matrices, tensors and other hypernumbers. Holors, thus defined, have been known for centuries but each has been developed more or less independently, accompanied by separate nomenclature and theory.
EN
The main aim of the study was to design a new system to measure punching and kicking forces as well as reaction times in combat sport athletes. In addition, the study examined whether there were any intergender differences in the force of punches thrown by boxers and kicking forces delivered by taekwondo athletes. Boxers (male, n = 13; female, n = 7) were examined for the force of single straight punches and taekwondo athletes (male, n = 14; female, n = 14) for force of single Apdolio and Dwit Chagi kicks. The punching bag was equipped with acceleration transducers and gyroscopes embedded in a cylinder covered with a layer to absorb shock as well as a set of colour signal diodes. Value of the punching bag’s acceleration was used for calculating: strike force; the punching location on the bag; and time of a strike. The relative error of force calculation was 3%; the relative error in acceleration measurement was less than 1%. The force of a straight rear-hand punch was greater than the force of a lead-hand punch among male and female boxers. The force of Apdolio kick delivered with a rear leg was greater compared to a lead leg among female and male taekwondo athletes. Significant gender differences were noticed in the force in both types of kicks. In boxers, intergender differences were reported only for the force of a punch thrown with the rear hand. Based on these findings, it was concluded that the modified punching bag is a good diagnostic tool for combat sports.
15
PL
W pracy opisano wyniki symulacji numerycznych obwodu sterującego tłumika z cieczą MR działającą w trybie ściskania. Określono wpływ wysokości szczeliny roboczej i prądu na strumień magnetyczny skojarzony z obwodem sterujacym. Zakładając harmoniczny ruch tłoka, obliczono prąd w obwodzie sterującym przy zasilaniu napięciem stałym i danych wysokościach szczeliny roboczej. Wyznaczono przykładowe charaterystyki tłumika, przedstawiające zależność wytwarzanej siły od wysokości szczeliny roboczej dla przyjetych wartości prądu.
EN
The paper summarises the results of numerical simulations of a control circuit for an MR damper operated in squeeze mode. The influence of the control gap height and current level on magnetic flux linkage was established. Assuming the piston motion to be harmonic, the current in the control circuit was computed under the constant-voltage supply conditions and for the specified gap heights. Damper force vs gap height plots obtained for the specified current levels are provided as an example of damper characteristics.
EN
The paper summarises the theoretical study of a magnetorheological (MR) damper operated in squeeze mode, intended to be used as an actuator in a semi-active mount system in a car motor. The structural design and operating principle of the damper are described and a simplified model of the MR fluid flow in the gap is presented. The plots of the damper force generated by the MR damper are obtained for monoharmonic piston motion with respect to the centre point of the gap height and in the conditions of the control coil being supplied with direct current.
PL
W artykule przedstawiono wyniki badań, których celem było określenie współczynnika tarcia, próbek stalowych przy określonej sile nacisku dla trzech konfiguracji chropowatości powierzchni. Siła nacisku wywierana na próbki odzwierciedla wartość wcisku, jaki występuje w stożkowym połączeniu czopowo-ciernym. Za pomocą wyznaczonego współczynnika tarcia wyznaczono wielkość momentu, jakim maksymalnie można obciążyć połączenie czopowo-cierne oraz siłę osiową, jaka jest potrzebna do montażu tego rodzaju połączenia. Wyniki badań obrazują zmiany współczynnika tarcia dla próbek z powierzchniami odtłuszczonymi i próbek, gdzie między badanymi powierzchniami współpracującymi ciernie wprowadzono czynnik smarny oraz wartości momentów skręcających w zależności od wartości współczynnika tarcia.
EN
For disintegration process control we need a quantity that respects objectively rock-disintegrating tool interaction with the elimination of human factor. From this, basic requirements for the evaluation quantity given below follow: is available in advance or at the moment of disintegration; minimises the influence of human factor on the resultant effect; evaluates objectively the disintegration process. A measure of efficiency of any disintegration process is the consumption of energy usually related to the unit volume of disintegrated rock; on the basis of analysis done theoretical and practical researches orientated towards the disintegration processes and the verification of objectivity when used in situ (in drilling and tunnelling), at present it is minimised specific volume energy that is the most objective evaluation quantity. This quantity has a general validity for dispersion processes, and thus its use even for the evaluation of diggability on the digging wheel of excavator has a rational basis. In connection with the GIS application for controlling the extracted quantity, an optimal tool is offered for the maximum efficiency of excavation process.
PL
W pracy przeprowadzono analizę siły wytwarzanej przez wibroizolator z cieczą magnetoreologiczną (MR) działającą w trybie ściskania w stanach quasi-statycznych. Opisano budowę wibroizolatora i model ściskania cienkiej warstwy cieczy MR. Wyznaczono charakterystyki wibroizolatora. Te charakterystyki obrazują przebiegi czasowe siły wibroizolatora i jej składowych oraz zależności siły od przemieszczenia i prędkości tłoka przy stałych wartościach natężenia prądu w cewce sterującej oraz sinusoidalnych przemieszczeniach tłoka.
EN
The study summarises the quasi-static analysis of the damping force generated by a vibration isolator with magnetorheological (MR) fluid in the squeeze mode. The isolator’s structure is described and the model of a simple squeeze-film device is outlined. Force characteristics of the isolator were obtained, plotting, the time patterns of the force and its components determined under sine piston displacements and constant levels of input current in the control coil, as well as force-displacement and force-velocity loops.
20
EN
The article is dedicated to a universal model force control system for small static loads. The requirements and the hardware configuration of the control system are presented. The authors also describe basic algorithms for controlling research processes, including issues related to force adjustment such as the automatic force loading and its measurement, the manual force exertion and its measurement, the automatic movement of the object, measuring of the force exerted on the object, as well as archiving and processing the measurement data. The exemplary results of verification tests were presented. Additionally, the possibility to analyse and archive the measurement data of the system is also shown. Finally, the authors describe other examples of applications of the developed control system.
PL
W artykule opisano modelowy uniwersalny układ regulacji siły do małych obciążeń statycznych. Przedstawiono wymagania oraz konfigurację sprzętową układu regulacji. Podano podstawowe algorytmy sterowania procesami badawczymi obejmujące zagadnienia związane z regulacją siły, takie jak: automatyczne wywieranie siły i jej pomiar, manualne wywieranie siły i jej pomiar, automatyczne przemieszczanie badanego obiektu i pomiar siły wywieranej na obiekt oraz archiwizacja i przetwarzanie danych pomiarowych. Przedstawiono przykładowe wyniki z badań weryfikacyjnych, zaprezentowano możliwość analizy i archiwizacji danych pomiarowych układu oraz podano inne przykłady zastosowań opracowanego układu regulacji.
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