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1
Content available remote Conductive Heat Transfer Prediction of Plain Socks in Wet State
EN
In this study, an algebraic model and its experimental verification was carried out to investigate the effect of moisture content on the heat loss that takes place due to conduction of sock fabrics. The results show that increasing moisture content in the studied socks caused a significant increase in their conductive heat loss. Plain knitted socks with different fiber composition were wetted to a saturated level, and then their moisture content was reduced stepwise. When achieving the required moisture content, the socks samples were characterized by the Alambeta testing instrument for heat transfer. Three different existing modified mathematical models for the thermal conductivity of wet fabrics were used for predicting thermal resistance of socks under wet conditions. The results from both ways are in very good agreement for all the socks at a 95% confidence level. In the above-mentioned models, the prediction of thermal resistance presents newly a combined effect of the real filling coefficient and thermal conductivity of the so-called “wet” polymers instead of dry polymers. With these modifications, the used models predicted the thermal resistance at different moisture levels. Predicted thermal resistance is converted into heat transfer (due to conduction) with a significantly high coefficient of correlation.
EN
Green roof constantly suffers from the water stress that is developed during prolonged drought seasons. In general, periodical irrigation is required to ensure plant growth and hence serviceability of green roofs. Biochar, a carbon sink material, has been proposed as a substrate amendment in green roofs for enhancing water retention ability of soils. This study aims to conduct an assessment of the irrigation efficiency of green roofs with different biochar additions (0%, 5%, 10%, 15% and 20%; v/v) under sub-tropical climatic conditions. In order to achieve this objective, outdoor monitoring as well as numerical modeling using HYDRUS-1D was conducted. Soil columns mixed with different proportion of biochar were prepared. These columns were subjected to different irrigation schemes (three irrigation frequencies were assessed (i.e., per 3, 7 and 10 days after irrigation or rainfall); moreover, three irrigation amounts for the three irrigation frequencies were considered (i.e., to a fixed amount (FA10mm), to Field water holding capacity (FC) and to Saturated moisture content (SR))). As suggested from the results: (1) Biochar significantly improved water holding capacity and plant available water. 20% biochar delayed the onset of the significant plant wilting phenomenon by approximately 3 days and maintained the maximal transpiration rate of vegetation in the dry period. (2) As compared to irrigation scheme A (irrigation to FC per 7 days), the efficiency of scheme B (irrigation to SR per 10 days) was more vulnerable to the biochar amendment. Moreover, the total irrigation water and days of water stress decreased with an increase in the biochar addition. Furthermore, the combination of 20% biochar and irrigation scheme B could be the optimal choice for maintaining the health of the green roofs and water conservation. The present study helps to obtain desired outcomes in green roofs, e.g., stormwater management, cost reduction as well as providing greening.
PL
Woda jest często niepożądanym składnikiem polimerów, substancji farmaceutycznych i produktów spożywczych. Zbyt duża zawartość wody skraca czas przydatności do spożycia ryżu, utrudnia przetwarzanie w produkcji farmaceutycznej (przykładowo formowanie tabletek) i może powodować problemy z jakością produktów z tworzyw sztucznych. W związku z tym bardzo ważnym zadaniem jest wyznaczanie zawartości wody w różnych rodzajach materiałów. Oprócz pojęcia „zawartość wody" często można spotkać się także z pojęciami „zawartość wilgoci” i „strata po suszeniu". W tym artykule (część 1) zajmiemy się omówieniem znaczenia podanych terminów oraz niektórych technik wyznaczania wspomnianych wielkości.
PL
W artykule przedstawiono wybrane zagadnienia docieplania ceglanych ścian zewnętrznych i muru pruskiego od strony wewnętrznej. Zewnętrzne ściany ceglane budynków o charakterze zabytkowym, podobnie jak ściany budynków wzniesione w konstrukcji tzw. muru pruskiego, wymagają zachowania dekoracyjnych walorów fasady. Projektowanie remontu takich przegród wymaga wiedzy z dziedziny budowy takich przegród, ich stanu wilgotnościowego, wpływu stosowanych materiałów i warunków eksploatacji na prognozowane zmiany ilości wody w poszczególnych częściach ściany.
EN
The article presents some of the issues related to the thermal insulation of external brick walls and the Prussian wall from the inside. The external brick walls of historic buildings, like the walls of buildings erected in the so-called technology half-timbered buildings require the decorative qualities of the façade. Designing insulation from the inside of such walls, requires knowledge of the construction of such partitions of their moisture status of the existing part, the impact of thermal insulation material and operating conditions on the projected changes in the amount of water in individual parts of the wall.
EN
This study is mainly focused on the intrinsic fiber parameters and their influence on the mechanical properties of the hybrid composites. Cellulosic fibers are extracted from mesocarp of Cocos nucifera fruit and outer mat of Luffa cylindrica fruit. The inherent fiber parameters such as fiber diameter, lumen diameter, cell wall thickness are observed under light microscope. Micro-fibrillar angle is found using X-ray diffraction technique. Three varieties of hybrid polymer composite samples are fabricated using Cocos nucifera and Luffa cylindrica fibers as reinforcements in the ratio 2:1, 1:1 and 1:2 respectively employing hand layup technique with their combined weight maintained as 30%. Significant response in the Load Vs Deflection curve and mechanical properties of the hybrid composites are found attributing to the difference in the respective weight proportion of the constituent fibers in the hybrid composite system. Results exemplify that the hybrid composite sample comprising Cocos nucifera and Luffa cylindrica fibers in the ratio 1:2 capitulates the maximum flexural strength and impact strength of 31.05 MPa and 14.24 kJ/m2 respectively when compared with other hybrid composites. The reason for the difference in mechanical strength of hybrid composite samples containing two different fibers is found to be related to the built-in architecture and physical characteristics of the constituent fibers. The morphology of the fractured samples are examined and reported. It is concluded that properties of hybrid composites can be tailor made depending upon the requirements either by using the Cocos nucifera fibers to impart ductility or Luffa cylindrica fibers to impart brittleness.
7
Content available remote Practical application of the microwave oven in the geotechnical laboratory
EN
The main purpose of the paper is to present the usefulness of microwave ovens in the everyday work of geotechnical laboratories. Microwave ovens are commonly used to determine soil moisture and to dry soils that are too moist for other laboratory tests. The activities related to the above processes are not standarized in the majority of countries. The only available guidelines are based on the research projects. For the purpose of this particular research 345 tests have been conducted for moisture content determination for 3 soil types: fine sand (FSa; SP - poorly graded sand), sandy gravel (saGr; GW well graded gravel-sand mixtures) and silty clay (siCl; CH - inorganic clay of high plasticity), using both - standard and microwave methods. The research cycle consisted of 3 different variants which includes soil moisture content, specimen initial mass, number of specimens in microwave oven and their placing. It was established that different factors have impact on the length of the process and it lasted between 2 to 17 minutes. During the heating different undesirable phenomena were observed, e.g., soil explosions or melting and glowing of clay. Based on the above research results this paper introduces guidelines for the soil drying process in the microwave oven (the optimization of the procedure and handling of the dried samples).
8
Content available remote Znaczenie diagnostyki przy renowacji zawilgoconych obiektów
9
Content available remote Współcześnie stosowane metody osuszania murów
PL
Woda we wszystkich stanach skupienia: stałym, ciekłym i gazowym, jest największym wrogiem wielu materiałów i konstrukcji budowlanych, zwłaszcza obiektów murowanych. Istnieją jednak skuteczne metody osuszania, stanowiące jeden z wielu elementów prac renowacyjnych. Przed przystąpieniem do nich najważniejsze jest określenie przyczyn zawilgocenia, a dopiero później zastosowanie metod osuszania. Artykuł porusza problemy zawilgoconych murów. Stanowi też próbę przedstawienia i porównania sposobów ich rozwiązywania.
EN
Water in all states of existence: solid, liquid and gaseous, is the greatest enemy of many building materials and structures, especially masonry. However, there are effective methods of drying them, which are one of the many elements of restoration work. They lead to the removal of excess moisture from the septum. Prior to joining them, it is important to determine the cause of the dampness, and only then the possible methods of drying. This article deals with the problem of damp walls. It attempts to present and compare contemporary methods of drying them.
10
Content available remote Wpływ wilgoci na trwałość betonu komórkowego
PL
Badanie mrozoodporności wg normy PN-EN 15304 często nie pokrywa się z zachowaniem materiału w warunkach eksploatacyjnych. Dotyczy to zazwyczaj ABK o dużej porowatości. W związku z tym przeprowadzono badania porównawcze mrozoodporności ABK wg PN-EN 15304 (wilgotność całkowita) oraz mrozoodporności ABK w stanie wilgotności ok. 30%.
EN
The freeze/thaw resistance testing according to European Standard PN-EN 15304 often does not coincide with behavior of the material under operating conditions. This usually applies to AAC with high porosity. Therefore, comparative research of freeze/thaw resistance AAC: according to PN-EN 15304 (total humidity) and in the humidity state about 30%.
11
PL
W artykule przedstawiono algorytm postępowania oraz przykładowe urządzenia stosowane w celu określenia i rozwiązania problemu zawilgocenia przegród budowlanych przylegających do gruntu. Problemy z wilgocią dotyczą zarówno historycznych, jak i obecnie wznoszonych obiektów. Woda, która wnika kapilarnie w przegrody, powoduje nieodwracalne szkody w materiałach, które mogą doprowadzić do destrukcji budynku. Nieprawidłowa diagnostyka prowadzi do przyjęcia niewłaściwych metod hydrorenowacji, co powoduje dalszą degradację przegród. Algorytm postępowania przedstawiono na przykładzie diagnostyki prowadzonej na zawilgoconych obiektach.
EN
This article are presented algorithm of handling and example of devices used to determine and solve the problem of moisture in barrier walls in contact with ground. Problem with moisture concerns both historical buildings and recently built objects. Water that penetrates barrier walls by capillary action causes irreversible breakages on materials, that leads to destruction of the building. Improper diagnostics leads to adopting incorrect methods of hydro-renovation, what will cause further degradation of barrier walls. Algorithm of handling is presented by the case of diagnostics on damp objects.
12
Content available remote Transport wilgoci w betonie komórkowym
EN
The study assessed the potential of waste by-products from the Cypriot winery industry as raw material for solid biofuels. Two different biomass blends were pelletized and assessed as an energy source for domestic hot water boilers. The samples were composed of Grape Pomace (P1) and Grape Pomace & Vine Shoots Blends (P2) provided by a Cyprus winery: Aes Ambelis (Nicosia, 35°01’12.4"N 33°09’19.5"E). The raw material was dried and pelletized at the facilities of the Agricultural Research Institute (ARI), Cyprus. The pellets were analyzed for moisture and ash content using well-established standardized methods at the Sustainable Solid Fuels Lab of Frederick University, Cyprus. Combustion tests with the pellets were also carried out at the Boilers Lab of Frederick University. The measurement campaign focused on flue gas analysis – in particular carbon monoxide, carbon dioxide, oxygen, lambda – as well as water temperature and boiler efficiency. The results obtained from analysis of the samples showed that most of the examined pellets satisfied the minimum requirements of EN ISO 17225-2 and EN ISO 17225-6 standards for woody and non-woody pellets respectively. Ash content and moisture content for both samples also complied with the standards. The results of the measurement campaign were in good agreement with results delivered by other studies conducted for similar biomass raw material. Study results showed that grape pomace and grape pomace vine shoots blend could potentially be used as an energy source for producing heat which could be exploited for the domestic and industrial sectors. Harvesting this waste stream for energy production purposes could offer economically and environmentally smart solutions for the winery industry in Cyprus, satisfying the circular economy principles which are currently at the forefront of European environmental policy.
EN
The article presents a method of non-destructive evaluation of the moisture content in saline brick walls. This method is based on the use of artificial neural networks (ANNs) that are trained and tested on a database that was built for this purpose. The database was created based on laboratory tests of sample brick walls. The database contains over 1100 sets of results. Each set consists of two parameters that describe the dampness of the tested sample walls, which were determined using dielectric and microwave methods, and also three parameters that describe the concentration of salts in these walls. The ANN with back propagation error and the Broyden–Fletcher–Goldfarb–Shanno learning algorithm (BFGS) was used. It was shown that the proposed method of assessment allows reliable results to be obtained, which was confirmed by the high values of the linear correlation coefficient for learning, testing and experimental validation.
PL
W referacie przedstawiono problemy związane z wykonawstwem oraz badaniami przyczyn zawilgocenia i stopnia zasolenia ścian (fundamentów) istniejących obiektów na przykładzie murów podziemia kościoła św. Wincentego w m. Biłohiria.
EN
The paper presents problems related to the execution and investigation causes of dampness and salinity of the walls (foundations) of existing objects on the example walls of the basement of Św. Vincent in Bihohiria.
18
Content available remote Wybrane problemy remontowo-konserwatorskie zabytkowego kościoła w Dąbrowicy
PL
W artykule przedstawiono zakres wykonanych prac inwentaryzacyjnych barokowego kościoła w Dąbrowicy. Na podstawie przeprowadzonej inwentaryzacji sporządzono rysunki architektoniczno-budowlane, a następnie dokumentację fotograficzną, badania zawilgocenia i uszkodzenia murów przez sole. Opracowano sposoby prac konserwatorskich oraz zabezpieczeniowych, a także podano warianty naprawy z zaleceniem co do wyboru jednego z nich.
EN
This paper presents the range of inventory of the baroc church in Dubrovytsia. On the inventory were made architectural and construction drawings and the photografic documentation. Next were made the moisture tests and the tests of wall damages by salts. Finally the methods of the conservations and protections have been presented and also it has been given variants of the repair with the recommendation to choose one of them.
PL
W artykule przedstawiono wyniki badań zależności pozornej wartości współczynnika przewodzenia ciepła λ cegły pełnej od stopnia nasycenia wodą oraz roztworem siarczanu sodu. Badania przeprowadzono metodą stacjonarnego przepływu ciepła w przypadku następujących stopni nasycenia: 25, 50, 75, 100%. Wyniki eksperymentu potwierdzają negatywny wpływ wilgoci na przewodność cieplną materiału. Wartość współczynnika przewodzenia ciepła λ rośnie wraz ze wzrostem stopnia nasycenia materiału wodą lub roztworem soli. Zaobserwowano, iż obecność roztworu Na2SO4 oraz kryształów dziesięciowodnego siarczanu sodu ma mniej negatywny wpływ na przewodność cieplną badanych próbek niż obecność czystej wody.
EN
This paper presents the experimental results concerning the relation between the apparent thermal conductivity coefficient of brick and its water or Na2SO4 solution content. The research is conducted using stationary technique for the dry specimens, as well as the ones containing 25%, 50%, 75% and 100% water or sodium sulphate solution. The experimental results confirm the negative influence of water or sodium sulphate solution on the thermal properties of material. The study shows that the presence of Na2SO4 solution mitigate the negative influence on brick’s thermal conductivity coefficient.
20
Content available remote Wilgotność ścian w budynkach z betonu komórkowego
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