Wyniki wyszukiwania - Biblioteka Nauki

1

Factors Affecting the Measurement of the Percentage of Gaseous Products from Boron-based Fuel-rich Propellants

100%

Liu L.-L. , He G.-Q. , Wang Y.-H. , Liu P.-J.

Central European Journal of Energetic Materials

|

2014

|

tom Vol. 11, no. 1

15--29

EN

Acid-washed asbestos, carbon fibre, and MgO with carbon fibre were used as the filter media in order to compare their filtering qualities in the estimation of the percentage of gaseous products (PGP) arising from the combustion of singlebase propellants, double-base propellants, and boron-based fuel-rich propellants. The comparison was based on an analysis of the experimentally registered influence of the propellant formulation, the propellant load, the maximum chamber pressure and the thickness of the MgO filter layer on the PGP from the fuel-rich propellant, and in particular on the PGP produced by combustion of boron-based fuel-rich propellant. The results showed that the experimental values of the PGP were closer to the theoretically predicted values when carbon fibre mixed with MgO powder was used as the filter medium. The PGP of boron-based fuel-rich propellant increased when the AP was in part replaced by HMX, when the AP content was increased and when boron was in part replaced by magnesium-aluminum alloy. In terms of the apparatus used in these experiments, the propellant loading density was found to have little correspondence with the PGP for boron-based fuel-rich propellant. The optimal propellant loading density for the chamber volume of 85 cm3 was found to be 2-2.5 g, in view of the reliability and safety of the experiment. It is emphasised that the thickness of the MgO filter layer is very important for the accuracy and reliability of the experiment, and that the optimum should be determined by experiment.

2

Filtration performance simulations based on 3D structural data of real filter media

88%

Lehmann M. J. , Hiel S. , Nibler E. , Durst M.

Journal of KONES

|

2008

|

tom Vol. 15, No. 3

277-284

EN

The performance of a particle filter is primarily determined by its media. Today's filter media is a composition of different layers known as MULTIGRADE or MICROGRADE media. Selecting the right combination of layers requires a lot of experience. Recent progress now enables the simulation of complex structures to support the development by adding information about the media utilization. However, published results point out that the local inhomogeneity of the fiber structure plays an important role. Thus computer models have been developed to reproduce 3D fiber structures. However, these 3D fiber structures are still simplified models, as they have just a few input parameters and do not account for the production process. But state-of-the-art simulation software, such as GeoDict, provides the opportunity to import 3D images of real fiber structures as initial geometry. Micro-tomography now promises to deliver this quantitative data about the real 3D fibrous structure. In this paper first results are presented, indicating that we extracted the true fibrous structure of a synthetic media by segmentation of the raw XCT data with the software MAVI. In contrast to other publications, the packing density of the media was not used as fitting factor, but obtained without a priori knowledge. The results discussed show a reasonably good agreement with measured data for packing density, fiber diameter distribution, initial pressure drop and initial efficiency. However, it is crucial to select a region of interest large enough to be representative.

3

Optimization of Response Surface Methodology for Removal of Cadmium Ions from Wastewater using Low Cost Materials

75%

Mohammed R. A. , Abdulhasan M. J. , Raheem S. A. , Alwared A. I. , Mohammed N. A. , Kadhim R. F. , Al-Bayati A. D. J.

Journal of Ecological Engineering

|

2023

|

tom Vol. 24, nr 8

146--156

EN

This study goal to the ability of using low cost materials representing thermestone and aluminum solid wastes in water filtration by using a pilot plant constructed in wastewater treatment plant to remove cadmium ions (Cd(II)). Response Surface Methodology (RSM) used to optimize the optimal parameters that affecting the performance of filter units, these parameters are time, Cd(II) concentration, and filtration rate. These optimized parameters were 9 hr., 5 ppm, 10 l/hr. with removal efficiency of Cd(II) for A-Filter, T-Filter, S-Filter, and A-T-S-Filter was 94%, 95%, 86.8% and 90%, respectively. The result shows that the T-filter has higher cadmium removal efficiency than A-filter, S-filter and S-T-A- filter. While A-filter has a higher removal efficiency of cadmium than the S-filter and S-T-A- filter. While the S-T-A- filter has higher efficiency than S- filter. The result obtained from RSM was good Agreement with the result of experiments. As a result, the optimized process in this paper can be widely utilized with high removal ratio of Cd(II) ions from wastewater samples.

4

Wymagania stawiane materiałom filtracyjnym

75%

Jeż-Walkowiak J.

Ekonomia i Środowisko

|

2013

|

tom nr 2

70--80

EN

In the paper the requirements for filtration materials used for water production are presented. The issue was described according to Polish and European standards. The physical and chemical parameters of materials are presented as well as issues related to transport and filter operation.

PL

W większości wysokoefektywnych systemów uzdatniania wody powierzchniowej filtracja pospieszna występuje po procesie koagulacji i sedymentacji oraz przed chemicznym utlenianiem i adsorpcją. W systemach uzdatniania wody podziemnej proces filtracji pospiesznej występuje najczęściej po napowietrzeniu wody, a podstawowym celem filtracji jest wówczas odżelazianie i odmanganianie we właściwie dobranych złożach filtracyjnych, w których zachodzą procesy katalitycznego heterogenicznego utleniania tych domieszek.

5

Recent advances in engine air cleaners design and evaluation

75%

Jaroszczyk T. , Pardue B. A. , Holm C. E.

Journal of KONES

|

2004

|

tom Vol. 11, No. 1-2

259-275

EN

The development of engine air cleaners is based on filter performance requirements, engine operational environment, available space, filter media properties, and filter element technology. The design process includes analyses of theoretical and empirical models describing precleaner and filter media separation/filtration performance and airflow in filter housings and through filter elements. Filter media are selected based upon these. models and simplified laboratory tests. Since many new motor vehicle designs offer extremely limited space for an engine air induction system, this paper concentrates on new reduced-volume filters, including direct-flow fluted and pleated compact engine air filters. The grawimetric method is still commonly used in engine air filtration technology for air cleaner, filter element, and filter media testing. However a new test method for fractional efficiency measurements is in the final development stage. The paper discusses this new method and provides data on filter grawimetric and fuctional efficiencies.

6

ISO 21083 : nowa norma międzynarodowa do określania skuteczności filtracji nanocząstek

63%

Jakubiak S.

Podstawy i Metody Oceny Środowiska Pracy

|

2019

|

tom Nr 2 (100)

7--17

PL

Nowa norma międzynarodowa ISO 21083 definiuje metodę badania materiałów filtracyjnych podczas filtracji nanocząstek o kształcie zbliżonym do kulistego. Opisana procedura może być stosowana do wyznaczania parametrów operacyjnych materiałów filtracyjnych dowolnych klas. Skuteczność filtracji jest wyznaczana na podstawie uśrednionych wyników uzyskanych dla próbek badanego materiału w stanie wyjściowym oraz po neutralizacji ładunku w oparach 2-propanolu. Norma nie wprowadza podziału na klasy filtrów, a w raporcie końcowym z badań są podawane frakcyjne skuteczności zatrzymywania cząstek. Zakres tematyczny artykułu obejmuje zagadnienia zdrowia oraz bezpieczeństwa i higieny środowiska pracy będące przedmiotem badań z zakresu nauk o zdrowiu oraz inżynierii środowiska.

EN

The new international standard ISO 21083 provides a method of testing filter media during the filtration of spherical shaped nanoparticles. The described procedure can be used to determine operating parameters of filtration materials of any classes. The filtration efficiency is determined on the basis of averaged results obtained for samples of the tested material in the initial state and after neutralization of the charge in the 2-propanol vapour. The standard does not introduce a division into filter classes, and in the final report of the tests, fractional particle retention efficiencies are given. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

7

Filtration Properties of Nonwovens

63%

Gądor W. , Jankowska E.

|

1999

|

tom Vol. 5, No. 3

361--379

EN

This paper presents the results and conclusions from experimental investigations concerning filtration properties of nonwovens. The needled nonwovens were made from polyester fibres (PTE) with average fibre diameter 12 pm and polypropylene fibres (PP) with average fibre diameter 32 f im. Nonwovens were produced out of each of those fibres or out of a mixture of polyester and polypropylene fibres. This paper also presents investigations of nonwoven fabric made of polypropylene fibres (PP) with average fibre diameter 2.6 /zm, which was formed according to melt-blown technology. Oil mist, as challenge aerosol, was used to evaluate the performance of filter media at various aerosol velocities. The average oil mist test aerosol particle diameter was 0.3 /zm. Filter penetration was measured at oil mist concentration 0.24 g/m3.