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EN
Based on the mechanical properties of stretch fabrics and Laplace’s law, the mathematical models have been developed enabling one to determine the values of the relationship between the fabric strain and the circumferential stress depending on pressure and diameter of the body. The results obtained refer to the values of the parameters assessed for the initial phase of their exploitation, which allow us to preliminarily predict the values of these parameters.
EN
The mathematical model for calculating the response time of the compression ratio of the mechanism for compression ratio changing (MCRC) is presented in this article. This revealed the influence of various engine factors with the connecting rod and crank mechanism (CRCM) on the operation of the MCRC (for example, the rate of the compression ratio change). The results of the study of the operation of the MCRC indicate a strong influence of the values  (relative area of flow passage of channels) and р (pressure) on the response time τ in the field of their small values. This indicates that with insignificant changes of the area of flow passage of channel of the hydraulic lock and the minute oil pressure in the cavities, a significant response rate of the MCRC is ensured. The results demonstrate the possibility of speedy compression ratio change in the engine with the MCRC. Calculation studies showed that the mechanism full operation occurs quickly (0.02 s per unit εx), which indicates the expediency of using such a high-pressure pump in a four-stroke gasoline engine with CRCM. The mechanism movable body complete movement (S = 4 mm) at the oil temperature in the hydraulic system of 45°C and pressure on the body of p = 60 bar are stated to occur for 0.2 s.
EN
In recent years, the development of IT systems for fleet monitoring was observed. Tire pressure monitoring systems are constantly improved. Decreased values in tire pressure can cause deformation of tires. Monitoring of tire pressure is an important function in oversized transport trucks. Tire pressure and rolling resistant influence fuel consumption. The purpose of this paper was to determine the impact of tire pressure on fuel consumption in a fleet of trucks with tire pressure monitoring system installed and to determine the impact of other factors that may affect fuel consumption, such as the vehicle weight, brake usage and cruise control usage. The results of the research were developed using a multiple regression model describing the above dependence.
4
Content available remote Bezpieczne sterowanie układami pneumatycznymi. Podstawowe funkcje
PL
Bezpieczne sterowanie układami pneumatycznymi polega na odcinaniu i uwalnianiu energii sprężonego powietrza w stanach zagrożenia dla urządzeń i użytkowników.
EN
In the present work, a solution to the problem of viscous flow in a rectangular region with two moving parallel walls is obtained by using a hybrid finite volume scheme. The discretized governing equations are solved iteratively, and thereby the flow variables are computed numerically. The results for velocity and pressure in horizontal and vertical directions through the centre of a rectangular region are elucidated. The nature of velocity profiles and pressure for different Reynolds numbers in the horizontal and vertical directions through the geometric centre was analyzed with the help of pictorial representations. The present results are compared with the available benchmark results and we have found that they are not in disagreement.
EN
To transport of the air in the pipeline, an analytical model is developed that takes into account the gas velocity, its kinematic and dynamic characteristics - density, viscosity depending on the pressure in a given space of the pipeline. The analytical model makes it possible to calculate the coefficient of friction of gas transportation in the pipeline at intervals of the absolute pressure from 220 to 2 kPa and M < 1 Mach numbers, depending on the diameter and length of the pipeline and physical and technological characteristics of the gas. The K1* aspect ratio is proposed, which characterizes in time the ratio of the dynamic force of movement of gas to the static pressure related to the diameter of the pipeline. The coefficient of air friction was modeled according to the vacuum pressure as a parameter of density and air flow. Air flow was taken from 1.917·10-3 m 3/s to 44.5·10-3 m 3/s respectively, diameters from 0.030 to 0.070 m and Mach number was M = 0.005-0.13. At the vacuum and excess pressures with increasing of Reynolds number and decreasing of Mach number the gas friction coefficient increased linearly. According to the simulation results as the pressure loss and the diameter of the pipeline are increased the friction coefficient increased as well. Analogically, at the vacuum metric pressure when the pressure loss and the diameter of the pipeline are increased the friction coefficient increased. At the pipeline internal diameters of 22, 30, 36 mm accordingly for pressure losses from 2 to 14 kPa the coefficient of air friction varies from 0.006 to 54.527 respectively.
EN
The article presents the results of tests carried out on a single-cylinder of spark-ignition engine. The charge exchange process in the combustion chamber is very important to determine the possibility of improving the overall efficiency of the engine. Describes of impact modifications engine on open indicator diagrams. Open indicator diagrams show that the higher compression ratio is assumed, the higher the pressure in the system is. First parts of the research describes analysis of charge exchange on not working engine. Results of research presents different open indicators diagrams. Then the pressure results were obtained on the working engine. The possibilities of improving the overall efficiency of the engine by reducing the pumping loss, associated with the replacement of the air fuel mixture, were presented. The article describes the modification of a spark-ignition engine that affects the pressure change in the combustion chamber. The use of innovative methods of regulating the compression pressure gives a lot of positive effects.
EN
In this Paper, a parametric study on pipes buried in soil was performed illustrating the results of blast loading. Effects of various parameters such as the physical properties of water, oil, gas, air, soil, pipes, and TNT have been investigated. The arbitrary Lagrangian-Eulerian (ALE) method was employed using LS-DYNA software. The maximum pressure in a buried pipe explosive was observed at an angle of about 0° to 45° and the minimum pressure occurred at an angle of about 45° to 90°. Therefore, all figures in this study illustrate that fluid pressure levels in buried pipes can help in their stabilization. In generally, by increasing the 1.23 times of liquid density under the explosion, the pressure levels in the soil decreased by 1.3 percent. The gas pressure has been increasing more than oil and water pipes 39.73 and 40.52 percent, respectively.
PL
W artykule przedstawiono charakter zmian wybranych parametrów ilościowych i jakościowych wód termalnych ze złoża Cieplice w Jeleniej Górze. Scharakteryzowano warunki wypływu wód termalnych. Określono przyczyny i zakres zmian wydajności eksploatowanych ujęć oraz zmian ciśnienia na głowicy otworu C-1. Przeprowadzona analiza zmian parametrów ilościowych eksploatowanych ujęć potwierdziła, że wszystkie termalne ujęcia Cieplic ujmują wody z tego samego powiązanego hydraulicznie systemu szczelinowego. Omówiono zmiany wartości jonów fluorkowych w poszczególnych ujęciach wód termalnych Cieplic. Określono stopień nasycenia omawianych wód względem głównych minerałów skałotwórczych i prawdopodobnych produktów ich wietrzenia. Przedstawiono analizę zależności pomiędzy głównymi składnikami wód i jonami F–. Podjęto próbę określenia pochodzenia fluorków obecnych w wodach termalnych Cieplic. Najprawdopodobniej źródłem jonów fluorkowych oraz kwasu metakrzemowego w badanych wodach są rozpuszczające się krzemiany, glinokrzemiany oraz fluoryt.
EN
The article presents the nature of changes in selected quantitative and qualitative parameters of thermal waters from the Cieplice deposit in Jelenia Góra. The conditions of thermal water outflow and the characteristic of changes in the efficiency of exploited sources have been presented. Additionally, the causes of pressure changes on the head in the C-1 borehole were determined. All the thermal intakes in Cieplice capture water from the same hydraulically system in fractured rocks. This is confirmed by The analysis of changes in the quantitative parameters. The article describe the contents of fluoride ions in particular intakes of thermal waters in Cieplice. The degree of saturation of the discussed waters in relation to the main rock-forming minerals and probable products of their weathering was determined. An analysis of the relationship between the main water components and F– ions is presented. An attempt to determine the origin of fluorides present in thermal waters of Cieplice was made. The most probable source of fluoride and metasilicic acid are silicate, aluminosilicates and fluorite.
PL
Zarządzanie wartością ciśnienia w sieci wodociągowej w Bytomiu-Miechowicach przyczyniło się do redukcji ilości awarii o 80%. W przeciągu 2 lat straty wody ograniczono o około 120 000 m3.
EN
In this study, the influence of thermomechanical coupling effect - the effect of thermal expansion due to dissipation of the energy of plastic deformation, with and without taking into account the stored energy of plastic deformation (SEPD) for the distribution of stresses, strains, temperature, the applied pressure and the residual stresses is examined. The residual stresses remain in a thick-walled tube (a cylindrical thick-walled tank) after removing the internal pressure in the process of purely elastic unloading. The analysis is made on the example of an analitycal solution for a thick-walled tube subjected to a quasistatically increasing internal pressure for the case of adiabatic processes (without heat flow). Since the loading with internal pressure is quasi-static (monotonic), then neglecting the process of heat flow can lead to some different results in calculated stresses, deformations, temperature, internal pressure and residual stresses. The calculations for isothermal type of processes of deformations (without heat or ideal cooling) are also performed for the estimation of these differences. The results calculated for the process with heat flow should be intermediate between the values obtained for isothermal and adiabatic processes.
PL
W artykule przedstawiono sposoby obliczania maksymalnego ciśnienia krytycznego dla konstrukcji skutera podwodnego z użyciem wzorów analitycznych oraz analiz numerycznych.
EN
The article presents method of calculating the maximum external hydrostatic pressure for the construction of an underwater scooter. The calculations were performed using analytical formulas and FEM analysis in the Solid Works Simulation program. An experimental verification of the strength of the scooter structure in the pressure chamber was carried out. It made possible an initial verification of analytical formulas and the MES Solid Works Simulation software used in the issue.
15
EN
The aim of the research was to examine the pressure agglomeration process of agri-biomass waste ie. straw with an additive of 20% hard coal. The analyzed parameters included as independent variables the process temperature and the moisture content of the substrate mixture. During the experiment there were examined the maximum densifying pressures and the obtained granule density. The study of the agglomeration process was carried out on a laboratory stand SS-3 (open chamber). The process took place at temperatures of 30, 50, 70, 90°C and the moisture contents of the fuel mixture were 15, 20, 25%. During the test, a sample of 0.6 g was poured into the thickening chamber where, as a result of the piston movement, they were compacted. The high maxiumum densifying pressures (approx. 30 MPa in process temperature of 30°C) obtained while the thickening of straw mixture with 20% of coal indicate a low compaction ability of the material. Increasing the humidity of the compacted coal straw from 15 to 25% caused a decrease in the maximum thickening pressures, compaction and density. The highest density (1149 kg·m-3) was obtained at 20% material humidity and process temperature of 30°C.
PL
Celem badań była analiza procesu ciśnieniowej aglomeracji odpadów rolno-biomasowych, tj. słomy z 20% dodatkiem węgla kamiennego. Analizowane parametry obejmowały jako zmienne niezależne temperaturę procesu i zawartość wilgoci w mieszaninie substratów. Podczas eksperymentu zbadano maksymalne ciśnienia zagęszczania oraz gęstość uzyskanych granul. Badania procesu aglomeracji przeprowadzono na stanowisku laboratoryjnym SS-3 (zapatrzonym w otwartą komorę zagęszczającą). Proces przeprowadzono w temperaturach 30, 50, 70 i 90°C, a zawartość wilgoci w mieszaninie paliwowej wynosiła 15, 20, 25%. Podczas testu w komorze zagęszczającej umieszczano próbkę 0.6 g, w wyniku ruchu tłoka zostawały one aglomerowane. Wysokie maksymalne ciśnienia zagęszczania (około 30 MPa w temperaturze 30°C) uzyskane podczas zagęszczania mieszanki słomy z 20% węgla wskazują na niską zdolność zagęszczania materiału. Zwiększenie wilgotności mieszaniny słomy i węgla z 15 do 25% spowodowało zmniejszenie maksymalnych sił zagęszczających i gęstości. Najwyższą gęstość (1149 kg·m-3) uzyskano przy 20% wilgotności materiału i temperaturze procesu wynoszącej 30°C.
EN
The paper presents the results of geological investigations of ice-dammed clays from Wierzbica near Serock (Central Poland). Physical and mechanical properties of varved clays were determined mainly during in situ tests. Different available equipment and methods were used for determining current geological and engineering conditions. Static tests CPT(U), dilatometer tests (DMT) and pressure meter tests (PBP) were performed and compared. Deformation modulus E, shear strength cu, yield pressure σy, limit pressure pl, and other parameters were evaluated. The selected methods were compared with respect to differences between the obtained results. With the use of statistical methods, the variability of ice-dammed lake sediments is presented. For this reason, the parameters should be carefully estimated. The geological environment is still diverse and difficult to apprehend. Histograms of collected data illustrate distribution of mechanical properties of varved clays from Wierzbica.
PL
Cienkie powłoki stalowe w postaci wycinka sfery obciążone ciśnieniem zewnętrznym wykazują tendencje do utraty stateczności w fazie poprzedzającej wyczerpanie nośności plastycznej. Zjawisko wyboczenia powłok sferycznych było przedmiotem badań wielu autorów, a wyniki dotychczasowych badań teoretycznych i doświadczalnych zostały wykorzystane w zaleceniach projektowych wydanych w 2008 roku przez ECCS [9]. W pracy przedstawiono badania eksperymentalne wykonane na specjalnie w tym celu zaprojektowanym stanowisku badawczym. Próbki do badań zostały wykonane techniką wyoblania z blach przeznaczonych do głębokiego tłoczenia. Zinwentaryzowano geometrię początkową każdej z powłok za pomocą skanowania 3D i wykonano badania materiałowe stali użytej do wykonania powłok. Ciśnienie wymuszano za pomocą kompresora powietrza, a pomiary przemieszczeń były wykonywane przy zastosowaniu optycznego systemu pomiarowego Pontos-Aramis. Rejestrowano formy deformacji całej powłoki w trakcie stopniowego wzrostu ciśnienia także po utracie stateczności. Wszystkie dane pomiarowe rejestrowano automatycznie za pomocą dwóch komputerów. Wynikiem każdego z eksperymentów była nieliniowa ścieżka równowagi w postaci zależności ciśnienia od wybranego parametru przemieszczeniowego. W artykule zaprezentowano porównanie otrzymanych wartości ciśnień krytycznych z wynikami symulacji numerycznych wykonanych systemem COSMOS/M dla geometrii nominalnej oraz porównanie z wartościami nośności wyboczeniowych wynikających z zapisów EDR5th ECCS [9] oraz z propozycji przedstawionej w pracy [3].
EN
Thin steel shells in a form of spherical segment loaded by external pressure show a tendency to sudden buckling for a lower pressure than their plastic resistance. The buckling phenomenon of spherical shells was subject of investigations of many authors and hitherto results of theoretical and experimental research were used in European Design Recommendations published in 2008 by ECCS [9]. Experimental investigations performed on the deliberately designed and fabricated stand were presented in this paper. Specimens were manufactured by a metal spinning technique from steel sheets used usually to a deep drawing and stamping of metal objects. The actual shape of every specimen was determined by 3D scanning technique. Material investigations of steel sheets were performed as well. The pressure was exerted by the air compressor and displacement measurements were accomplished by optical measurement system Pontos-Aramis. Forms of deformations of the whole specimen were registered precisely at every step of pressure exertion till the final postbuckling stage. All measured data were registered automatically by means of two computers. The result of every experiment was presented in the form of equilibrium path as the relationship of the pressure p as a function of the chosen displacement parameter. The comparison of critical pressures obtained in experiments with results received in preliminary numerical simulations done by COSMOS/M was presented in the paper. Experimental results were compared also with buckling resistances proposed in [9] and [3].
PL
W artykule opisano proces spalania zachodzący w cylindrze silnika o zapłonie samoczynnym. Przedstawiono uszkodzenia turbosprężarek mogące wywierać wpływ na proces spalania na podstawie danych literaturowych.
EN
This article describes the combustion process of the compression-ignition engine in the cylinder. Examples of damage to turbochargers have been reported, which have varied effects on the combustion process. Based on what is written on the subject in the literature.
EN
A steep seam similar simulation system was developed based on the geological conditions of a steep coal seam in the Xintie Coal Mine. Basing on similar simulation, together with theoretical analysis and field measurement, an in-depth study was conducted to characterize the fracture and stability of the roof of steep working face and calculate the width of the region backfilled with gangue in the goaf. The results showed that, as mining progressed, the immediate roof of the steep face fell upon the goaf and backfilled its lower part due to gravity. As a result, the roof in the lower part had higher stability than the roof in the upper part of the working face. The deformation and fracture of main roof mainly occurred in the upper part of the working face; the fractured main roof then formed a “voussoir beam” structure in the strata’s dip direction, which was subjected to the slip- and deformation-induced instability. The stability analysis indicated that, when the dip angle increased, the rock masses had greater capacity to withstand slip-induced instability but smaller capacity to withstand deformation-induced instability. Finally, the field measurement of the forces exerted on the hydraulic supports proved the characteristics of the roof’s behaviors during the mining of a steep seam.
PL
Opracowano układ do symulacji urabiania złóż węgla o dużym nachyleniu w oparciu o warunki geologiczno-górnicze w kopalni węgla Xintie. W oparciu o wyniki podobnych symulacji, analiz teoretycznych i pomiarów terenowych określono skalę spękań skał stropowych nad stromo nachylonym wyrobiskiem oraz stabilność skała stropowych, a także obliczono szerokość obszaru w zrobach podsadzanego skałą płonną. Wyniki badań wskazały, że wraz z postępem prac wydobywczych, strop bezpośredni ponad stromym wyrobiskiem obsunął się do zrobów wskutek działania sił ciężkości, wypełniając ich dolną część. W rezultacie, strop w niższej części wyrobiska wykazywał lepszą stabilność niż skały stropowe w jego górnej części. Odkształcenia i pęknięcia stropu zasadniczego zarejestrowano głównie w górnych partiach wyrobiska, spękany strop zasadniczy utworzył tam układ belki klińcowej nachylonej w kierunku upadowej, niestabilny pod wpływem uskoku i wskutek oddziałujących deformacji. Analiza stabilności stropu wykazała, że wraz ze wzrostem kąta nachylenia, wzrasta wytrzymałość górotworu na niestabilność wskutek obsuwania się w kierunku nachylenia, z kolei maleje jego wytrzymałość na oddziaływania odkształceń. Ponadto, wykonane pomiary sił działających na podpory hydrauliczne potwierdziły wzorce zachowania się górotworu w trakcie prac wydobywczych w złożach o dużym nachyleniu.
20
Content available remote Detekcja i naprawa wycieków oraz planowanie ciśnień dla pneumatyki
PL
Niniejszy artykuł porusza kwestie związane z detekcją i naprawą wycieków oraz z planowaniem ciśnień dla pneumatyki. Autor pokazuje w nim, co robić, by uniknąć strat sprężonego powietrza w zakładzie produkcyjnym.
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