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EN
Fused Deposition Modelling (FDM) 3D printing technology has become popular for producing prototypes and final parts in various industries, including the automotive, aerospace, and medical sectors. The leakage of such components is often an important factor in determining their possible applications. This paper focuses on researching the influence of printing parameters on leakage and relating the results to the strength of parts produced using this technology. The printing parameters considered were temperature and layer height. PLA (polylactic acid) was chosen as the material due to its biodegradability and biocompatibility. Leakage measurements were carried out using an empty cylinder-shaped vessel filled with air under pressure. The leakage value was observed as a pressure drop over time. It was shown that 3D-printed FDM vessels are not perfectly leak-proof, but the value of observed leakage may be acceptable for selected applications (leakage below 2.5 Pa/s). The results showed a high correlation be-tween the height of the printed layer in both the leakage and strength of the tested samples, while reducing the height increased the tightness and strength of the 3D-printed parts. The effect of printing temperature was less significant.
EN
Geophysical methods, especially selected electrical and electromagnetic ones, have been used for many years for the non-invasive detection of leakages from water supply networks. In this paper, the author focuses on theoretical aspects and numerical simulations to analyse the possibilities and limitations of the application of the selected electromagnetic method, i.e., the ground-penetrating radar (GPR) method for the aforementioned purpose. Various measurement techniques are used in the GPR method but in the paper the author refers to the most commonly used technique known as short-offset reflection profiling (SORP). As demonstrated in the paper, the detection of water leakages into a homogeneous and isotropic geological medium using the GPR method is a simple matter. However, the detection of leakages occurring in heterogeneous ground subjected to strong anthropopression and with the presence of electromagnetic interference becomes a difficult task, and interpretation may be difficult or even impossible. An important issue analysed in the paper was the phenomenon of the scattering of electromagnetic waves on underground anthropogenic objects, which very often occurs in urbanised areas. The results of the numerical modelling carried out for various scenarios of water leakages into typical ground allowed the possibilities and limitations of using the GPR method for the detection of leakages from water supply networks to be determined.
PL
W artykule przedstawiono przykład zastosowania integralno-kapilarnego systemu hydroizolacyjnego do naprawy zawilgoconych i skorodowanych stropów w świątyni Nan Tien, znajdującej się w Berkeley na południe od miasta Wollongong w Australii. Analizie poddano kilka sposobów rozwiązania problemu przeciekających stropów żelbetowych, znajdujących się pod schodami wejściowymi do budynku świątyni. Zastosowano dostępne na rynku środki, które umożliwiły uszczelnienie konstrukcji.
EN
In the article author presented an example of the use of an integral-capillary waterproofing system to repair a damp and corroded ceilings in the Nan Tien Temple, located in Berkeley, south of the city of Wollongong, Australia. Several methods of solving the problem related to the soaking of RC ceilings under the entrance stairs to the temple building were analyzed. Means available on the market were used which made it possible to seal the structure.
5
Content available remote Degradacja MWK
PL
W artykule przedstawiono wady konstrukcji piwnic budynku mieszkalnego, zaprojektowanego w technologii białej wanny. Powstające rysy i przecieki wymusiły doszczelnienie wanny przez wykonanie dodatkowych hydroizolacji. W artykule przedstawiono analizę konstrukcji podziemnej budynku, przyczyny występowania przecieków oraz koncepcję naprawy nieszczelności. Celem artykułu jest zwrócenie uwagi na problemy wynikające z projektowania i wykonywania wanien szczelnych, a w szczególności konieczności uwzględnienia w obliczeniach skurczu betonu. Na podstawie wykonanych analiz sformułowano ogólne wnioski dotyczące projektowania żelbetowych wanien szczelnych.
EN
The article presents defects in the bedplate and basement walls in the multi-family building designed in the white bath technology. Already at the construction stage cracks and leaks through the reinforced concrete elements were formed, which made it necessary to seal the bath by making additional hydroinsulation. The paper offers an analysis of the underground building structure, presents causes of leaks and the concept of leak repair. The aim of the article is to draw attention to the problems resulting from the design and construction of sealed bathtubs, in particular the necessity to take into account in the calculations concrete shrinkage, as a result of which the bottom plate is scratched. On the basis of the analyses performed, general conclusions have been drawn concerning the design of the reinforced concrete airtight bath, which are aimed at avoiding damage and, in particular, leaks through the airtight baths.
EN
Several studies have been conducted to improve and model the lubricated contact between surfaces. The main subjects were defining the hydrodynamic parameters to reduce energy losses and protect the environment. Some of the proposed models have studied the effect of textures in hydrodynamic lubrication and have proved that adapted shapes and geometries can improve the performance of lubricated contacts. A hydrodynamic model was developed by assuming the roughness of the textured surface and considering the cavitation in a steady-state regime. The proposed model was validated and compared with the analytical model of Fowell et al. [1]. Three different textures shapes were considered. The results showed that the rough-textured thrust affects the hydrodynamic performance significantly. Thus, by increasing the arithmetic roughness of textured surfaces, the hydrodynamic pressure, and the lifting force increase depending on the texture shape. A rougher surface slightly increases the friction force for the three considered textures.
PL
Eksfiltracja jest zjawiskiem niekorzystnym i może powodować zrzuty patogenów na tereny mieszkalne (zurbanizowane), powodować przekroczenia standardów jakości wody i/lub stwarzać zagrożenie dla zdrowia ludzi mieszkających w sąsiedztwie zanieczyszczonych ściekami jezior i rzek. Ścieki pochodzące z eksfiltracji zawierają duże ilości zawiesin, mikroorganizmów chorobotwórczych, zanieczyszczeń toksycznych, związków organicznych, olejów i tłuszczów. Podejrzewa się, że w skali kraju występuje znaczna eksfiltracja ścieków z systemów kanalizacyjnych do gruntu i wód gruntowych, ale istnieje niewiele opublikowanych dowodów na istnienie tego problemu. W artykule podjęto próbę opracowania modelu matematycznego zjawiska eksfiltracji ścieków. Zaprezentowane przez autorów inżynierskie narzędzie do matematycznego opisu strumienia eksfiltrujących ścieków z pustki powstałej w gruncie spoistym do gruntu i wód gruntowych pozwala na oszacowanie objętości strumienia eksfiltrujących ścieków. Dalsze prace przewidują weryfikację otrzymanej zależności za pomocą symulatów numerycznych (HYDRUS, FEFLOW) i potencjalną modyfikację opisanej w niniejszej pracy metody.
EN
Exfiltration is an unfavorable phenomenon and can cause discharges of pathogens into residential areas (urbanized areas), cause water quality standards to be exceeded and/or pose health risks to people living in the vicinity of sewage-polluted lakes and rivers. Exfiltration wastewater contains large amounts of suspended solids, pathogenic microorganisms, toxic pollutants, organic compounds, oils and fats. It is suspected that on a national scale there is significant exfiltration of wastewater from sewage systems into the ground and groundwater but there is little published evidence of this problem. This paper attempts to develop a mathematical model of the phenomenon of wastewater exfiltration. The engineering tool presented by the authors for the mathematical description of the flux of exfiltrating wastewater from the void formed in cohesive soil into the ground and groundwater allows estimating the volume of the flux of exfiltrating wastewater. Further work envisages verification of the obtained relationship using numerical simulators (HYDRUS, FEFLOW) and potential modification of the method given in this paper.
EN
Most of the small water companies supplying a small number of consumers with water are struggling with the extremely tight budget, often making any large-scale modernisation impossible. In effect network managed by these companies is often very leaky and unreliable. One possible and cheap way of leakage reduction is the reduction of average pressure in the network. Thanks to new computing technologies, the device selection process for pressure reduction is accurate and easy to do. This study uses the hydraulic model to select required pressure reducing valves and correct locations accurately and adequately approximate the resulting absolute water loss reduction thanks to this approach.
PL
Większość małych przedsiębiorstw wodociągowych boryka się z problemami budżetowymi. Mogą mieć one wiele źródeł – obłsuga niewielkiej ilości odbiorców, wysoki poziom strat, konieczność zakupu wody z zewnętrznych źródeł. Czynniki te sprawiają, że wymagane nakłady na modernizacje sieci niejednokrotnie przewyższają możliwości finansowe przedsiębiorstwa. Jednym ze sposobów redukcji rzeczywistych strat wody jest obniżenie średniego ciśnienia w sieci. Dzięki nowym metodom obliczeniowym i symulacjom komputerowym dobór urządzeń redukujących ciśnienie i wybór lokalizacji ich montażu są znacznie ułatwione. W pracy skupiono się na ocenie możliwości wykorzystania modelowania komputerowego podczas wdrażania systemu zarządzania ciśnieniem w sieci wodociągowej.
PL
Infrastruktura tunelowa charakteryzuje się bardzo dużymi konsekwencjami potencjalnej awarii. Konieczne jest zatem właściwe kontrolowanie stanu jej deformacji poprzez pomiary wybranych wielkości fizycznych, np. odkształceń, temperatur i przemieszczeń, umożliwiających finalnie ocenę bezpieczeństwa budowy i eksploatacji danego tunelu. W artykule omówiono możliwości zastosowania punktowych pomiarów czujnikami strunowymi oraz geometrycznie ciągłych pomiarów światłowodowych DFOS. Współcześnie coraz częściej wykorzystuje się zalety obu tych technologii w celu stworzenia hybrydowych systemów monitorowania.
EN
Very high consequences of potential failure characterise tunnel infrastructure. Thus, it is necessary to properly control its deformation state by measuring selected physical quantities, e.g. strains and displacements, enabling the safety assessment of a given tunnel during its construction or operation. The paper discusses the possibilities of spot measurements by vibrating wire gauges and geometrically continuous measurements by distributed fibre optic sensors (DFOS). Today, the advantages of both technologies are increasingly being combined to create hybrid monitoring systems.
EN
Casting is the most economical way of producing parts for many industries ranging from automotive, aerospace to construction towards small appliances in many shares. One of the challenges is the achievement of defect-free cast parts. There are many ways to do this which starts with calculation and design of proper runner system with correct size and number of feeders. The first rule suggests starting with clean melt. Yet, rejected parts can still be found. Although depending on the requirement from the parts, some defects can be tolerated, but in critical applications, it is crucial that no defect should exist that would deteriorate the performance of the part. Several methods exist on the foundry floor to detect these defects. Functional safety criteria, for example, are a must for today's automotive industry. These are not compromised under any circumstances. In this study, based on the D-FMEA (Design Failure Mode and Effect Analysis) study of a functional safety criterion against fuel leakage, one 1.4308 cast steel function block, which brazed-on fuel rail port in fuel injection unit, was investigated. Porosity, buckling, inclusion and detection for leak were carried out by non-destructive test (NDT) methods. It was found that the best practice was the CT-Scan (Computed Tomography) for such applications.
EN
It is commonly known that the sealing performance of dynamic seals is significantly influenced by the surface finish. To reduce friction effect and leakage ratio, new generations of grooved lip or shaft have emerged, but only two computational models were performed up to now with a textured elastomeric lip: spiral groove in the axial direction or micro-cavities according to the circumferential direction. However, if the numerical results have confirmed the slight effect of the grooved lip on the rotary lip seal performances, it seems relevant to investigate the influence of such grooves on the reciprocating hydraulic rod seal behavior. Thus, the scope of this work is to perform a parametric study of the grooved lip throughout a one-dimensional elastohydrodynamic model by taking into account the elasticity of the lip and the shaft roughness. After confirming the validity of the current model, numerical simulations have been performed and compared with experiments. The effect of lip grooves on the hydraulic rod seal behavior in outstroke and instroke shaft motion has been underlined. Thereby, it is shown that the leakage and the average film thickness are sensible to both the depth and the density of the lip groove. Additionally, a slight effect of the pattern shape is observed on the friction force.
PL
W artykule omówiono zagadnienia związane z nieszczelnością regeneracyjnych obrotowych podgrzewaczy powietrza (ROPP) oraz przeprowadzono analizę ich nieszczelności. Wyodrębniono poszczególne składowe przecieku, tj. przeciek przez przenoszenie powietrza do spalin w pakietach grzejnych oraz przeciek bezpośredni, który rozdzielono na przeciek na gorącym i zimnym końcu podgrzewacza. Przeprowadzono analizę strat ciepła i energii elektrycznej wynikających z przecieków. Na podstawie przyjętego modelu przecieków wyznaczono łączne efekty modernizacji uszczelnień na przykładzie kotła OP-650. Zwrócono uwagę na warunki dotrzymania gwarancji, które powinny znaleźć się w kontrakcie na modernizację ROPP.
EN
The article discusses some issues related to leakage of rotary regenerative air heaters (RRAH) and presents the corresponding leak analysis. The particular leak components have been broken down into a leak due to air transfer in the heating baskets to flue gas and a direct leak divided into leaks at the hot outlet or cold inlet of the RRAH. The article provides analysis of the losses of heat and electrical energy resulting from leakage. Based on the adopted model of leaks, overall effects of sealing modernization have been determined for the OP-650 boiler. The article points out the guarantee fulfilment conditions which should be included in a contract for modernization of the RRAH.
PL
W artykule przybliżono problematykę nieszczelności wewnętrznej występującej w stojakach hydraulicznych sekcji obudowy zmechanizowanej. Przedstawiono wyniki kilkuletnich prac nad opracowaniem nowego zastoso­ wania konstrukcji bloku zaworowego z dwoma zaworami zwrotnymi oraz zaprezentowano wyniki badań stano­ wiskowych i w warunkach rzeczywistych.
EN
A powered roof support is an integral element of a longwall complex while a hydraulic leg is the basie component of the support. The operating characteristics of the section, and then of the entire powered roof support, depend on its operating parameters and reliability. This also has a significant impact on the efficiency of the entire longwall complex. The correct operation of hydraulic leg is therefore of key importance to the mining process. One of the things that can disturb the work of the leg is internal leakage which negatively impacts on the performance of the leg. Two types of tests were conducted to precisely determine the impact of these leaks on the leg's operating parameters: bench tests and tests in the actual conditions. The research included an analysis of operation of the leg for two currently used valve blocks and a new błock design to minimize the effects of in­ ternal leakage. The results confirmed that the developed valve błock design is suitable for underground systems. It managed to limit the negative effects of internal leakage in the leg both during bench tests and in underground conditions. The results can find broad application in legs used in sections intended for use in difficult mining and geological conditions.
18
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EN
This paper focuses on finding the diagnostic criteria that evaluate the pneumatic cylinder and detect the defects. Several undamaged cylinders were tested by acoustic emission before artificial defects were created in each one. The signals from the progress and retreat strokes were recorded and analysed into many parameters. The differences were identified by comparing the max root mean square from sensor A and the max root mean square from sensor B for one cycle in the retreat stroke. The damaged and undamaged cylinders were distinguished using the difference in energy values present in the signals of the two sensors in the retreat stroke. This paper is a continuation of a prior article and the extension of my work.
PL
Przedstawiona w opracowaniu analiza miała na celu określenie dokładności w systemie oceny stosowanym przy badaniu złączy spawanych metodą ultradźwiękową z zastosowaniem techniki DGS. Podjęto próbę wyznaczenia reflektora odniesienia DDSR jako funkcji grubości badanego materiału. Wyznaczony reflektor pozwolił na ocenę czułości reflektorów odniesienia przyjętych wg normy PN-EN ISO 17640.
EN
Today’s construction market of materials, contractors and building users, places new demands on individual building materials. Undoubtedly one such material is concrete, which is used in almost all construction projects as a binder for building materials. Therefore, it is necessary that this material is constantly subjected to new tests to find ways to improve its properties. Therefore, many scientists attempt to improve properties such as compressive strength, flexural strength and water resistance. One method is to modify the cement matrix with polymers.
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