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Die aggressive, wasserdampf- und alkalireiche Prozessumgebung einer allothermen Wirbelschicht-Vergasung bedingt die Korrosion diverser keramischer Anlagenkomponenten. Deswegen ist es von enormer Wichtigkeit, fur den zuverlassigen Einsatz in einem Vergaser geeignete Materialien, insbesondere fur keramische Auskleidungssteine und Filterkerzen, zu finden. Hier wurde deshalb die Korrosionsbestandigkeit verschiedener Auskleidungssteine charakterisiert sowie die Realisierbarkeit und Zuverlassigkeit eines keramischen Heisgasfiltersystems untersucht. The aggressive water vapour- and alkali-rich process environment of circulating fluidised bed gasification causes corrosion of several ceramic gasification components. Therefore, it is very important to find materials, especially refractory linings and hot gas filter candles, reliably working in a gasification environment. Here, the corrosion resistance of various refractories was characterized. Additionally, the feasibility and reliability of a ceramic hot gas filter system were examined.

Die drastische Verscharfung der Gesetzgebung bei der Festlegung neuer Emissionsgrenzwerte fur Kraftfahrzeuge erfordert den Einsatz einer effizienten Abgasnachbehandlung auf dem dieselmotorischen Sektor. Ein potenzielles Abgasreinigungskonzept fur die Absenkung der Partikelemissionen ist ein im Abgastrakt integrierter Dieselrus-Partikelfilter (DPF). In dieser Veroffentlichung wird ein experimentell validiertes Simulationsmodell vorgestellt, das den Lebenszyklus eines Dieselrus-Partikelfilters beschreibt. Das Modell zeigt Grundlagencharakter und lasst sich auf eine Vielzahl von Anwendungen aus dem Bereich der Gasfiltration ubertragen. The drastic tightening of regulations regarding emission limits of motor vehicles demands for an efficient exhaust gas treatment of diesel motor engines. One potential concept is an integrated diesel soot filter within the exhaust gas system. Basic requirement for a safe filter system operation is a fundamental comprehension of all involved individual processes. In this paper an experimentally validated CFD-model describing the life cycle of a diesel root filter is presented. Its results can be used to fully exploit the potential of such filter systems and provide a basis for a variety of applications in the field of gas filtration.

An der Filteranlage des Wasserwerks Langenau wurden Risse und Abplatzungen im Bereich der Spannkopfe von Spannbetonbindern festgestellt. Erste Untersuchungen zeigten, dass chloridinduzierte Korrosion vorlag. Da konstruktionsbedingt insbesondere die Spannbewehrung betroffen war, wurde eine eingehende Untersuchung der Schaden veranlasst, welche das Ziel hatte, neben der Entwicklung eines geeigneten Instandsetzungskonzepts auch Aussagen zur Resttragfahigkeit der Spannglieder zu treffen. Die Untersuchungen vor Ort offenbarten neben den Korrosionsschaden an den Spannkopfen auch ausgepragte Verpressfehler im Bereich der Festanker. Nachfolgend werden die Herangehensweise an die Problematik, die durchgefuhrten Untersuchungen und die dabei angewandten Untersuchungsmethoden, das entwickelte Instandsetzungskonzept (Konservierung des Ist-Zustands) und die Schlussfolgerungen zur Resttragfahigkeit erlautert. Auf Grundlage der Ergebnisse konnte die Korrosionsursache (Chloridquelle) eindeutig bestimmt und die Standsicherheit der Halle nachgewiesen werden. Die Halle wurde zwischenzeitlich instand gesetzt und wird zukunftig auf Wunsch des Bauherrn durch regelmasige Uberwachung auf neuerliche Auffalligkeiten kontrolliert. Assessment and Repair of Chloride Induced Corrosion on the Prestressed Concrete Binder of a Filtration System for Drinking Water On the filter system of the Langenau water work, cracks and spalling were identified in the area of the clamping chucks of the prestressed concrete binder. Initial investigations showed, that chloride induced corrosion was present. Since especially the prestressed reinforcement was affected, an expert assessment of the damages was conducted, which had the objective of, along with the development of an appropriate repair plan, making statements regarding the residual strength of the tendons. In addition to the corrosion of the clamping heads, the investigations revealed a distinctive injection defect in the area of the fixed anchor. Consecutively, the approach to the problem, the conducted investigations and the investigation methods used, the developed repair concept (conservation of the actual status) and the conclusions on the remaining carrying capacity are explained. Based on the results, the cause of the corrosion (the source of the chloride) could be clearly determined and the stability of the hall could be verified. In the meantime, the hall has since been repaired and in the future will be controlled through regular monitoring of noticeable problems at the request of the client.

Used canola oil was treated with commercially available adsorbents (HB 600, Magnasol, and Frypowder) and a UGA blend for flow rate study and oil quality improvement. Viscosity measurements offresh and used oil indicated that the oil temperature > 140C was best suited for active filtration. One percent adsorbent gave better flow rates than 2% except for Frypowder, which showed no difference in flow rates. All the adsorbents significantly improved the oil quality. Most significant improvement was observed in FFA values (15-20% and 24-35 % for 1 % and 2% adsorbent level, respectively) except for Frypowder, which resulted in least improvement (4 to 7%). Neither increasing the duration of treatment, prior to filtration, from 3 to 6 min, with 3% UGA blend, nor the multipass filtration treatment showed any significant improvement in oil quality. Pressure system was more promising for active filtration than vacuum and gravity systems. L'objectif de cette etude est d'examiner les parametres de filtration actifs comme la temperature, le taux d'adsorbant, la duree du traitement, l'effet de filtrations multiples, et de selectionner un systeme de filtration de l'huile de friture pour un usage de routine dans les etablissements de service alimentaire. Les mesures de viscosite indiquent qu'une temperature de 140°C ou plus est adaptee pour le traitement par adsorbant de l'huile.

It is becoming popular that both residential and commercial buildings in a densely populated urban city have fibre cables laid from a central office to the basement of the building. Category 5 twisted pairs are then used for in-building distribution. This paper introduces a pre-emphasis filter system to distribute MPEG-2 videos within a building using category 5 twisted pairs. A novel technique is used to identify the frequency response of a twisted pair cable to obtain the necessary preamplification at the transmitter. Simulation results are obtained for both conventional and fractional tap-line pre-emphasis filters for a 1000 ft category 5 twisted pair. The proposed system can be used by telecom companies to provide video-on-demand, internet connection and other interactive multimedia services. The system can also be utilized by hotels, hospitals, recreation centres and corporations to deploy their private intranets, VOD and multimedia information systems. © 1998 John Wiley & Sons, Ltd.

The Collective Protection System (CPS) is a continuous-use system designed to provide protection to personnel and work spaces within the ship from chemical, biological and radiological agents of hostile action. The CPS filter system consists of a High-Efficiency Particulate (HEPA) followed by an adsorbent impregnated charcoal. The CPS filter components are subjected to normal underway and exercise conditions (gases and vapors) that exist in the atmosphere surrounding the ship. The CPS can be subjected to missile exhaust, for which it was not specifically designed. CPS is a designed-in feature for new design ships. The USS Arleigh Burke was the first ship of a new class with a fully integrated CPS. Other new ship classes such as USS Wasp, USS Supply and USS Gunston Hall have CPS in living and selected working spaces. One purpose of this work was to determine if CPS filters removed or reduced missile toxicity levels in the ventilation supply to acceptable levels. A second purpose was to determine if the products of weapons exhaust damage or degrade the filters. An objective specific to the DDG 51 Class was to determine if the traditional Toxic Gas Damper systems could be eliminated. A series of land-based tests with live missiles, missile firings at-sea, and laboratory experiments were completed. The at-sea measurements were somewhat of a disappointment because favorable wind conditions were rarely available. The early work focused on the adsorbent charcoal. The results showed that the two-stage CPS filters adequately removed toxic levels of hydrogen chloride. There is evidence that the HEPA filter element alone may not adequately remove hydrogen chloride. It was concluded that elements of the CPS including filters, mixing/dilution, and ship geometry collectively prevent missile exhaust products from entering the ship. The degradation of the filters from missile firings is minimal and less than that of the natural marine atmosphere. The toxic gas dampers are not required when the two-stage filters are used.

During the BOF process for the production of crude steel, the specific amount of dust emitted is of the order of 2 % of the steel weight at turn down. The process gas conveys the dust through the boiler system into the primary and secondary dust catchers. The transportation of dust particles is influenced by blowing parameters; physical properties of process gas and of dust phases; and, type and layout of the converter and the filter system. In this work, a numerical simulation model is developed that simulates the pneumatic conveyance and sedimentation of primarily coarse dust particles in the BOF gas cleaning system. Comparison is then made of predicted coarse dust characteristics with values for dust sampled from an existing plant in order to verify the plausibility of the developed model.

The amounts of dust, protein, and allergens in vacuumed floor covering samples taken from both schools and homes in Norway have been investigated. Classrooms contained significantly more crude dust per unit area than homes, while the mean protein content per unit area was somewhat higher in homes. The main allergen exposure problem in classrooms was that of pet allergens; the contents of dog allergens and the major cat (Felis domesticus) allergen Fel d I per unit area were significantly higher in school classrooms than in homes of families who do not keep pets. The mite and food allergens, on the contrary, were more prevalent in homes. Carpeted floors in schools and homes contained significantly more dust, proteins, and allergens than smooth floors (P < 0.05). Fel d I was detected in the vacuum cleaners' filter system in concentrations from < 1 ng to 1080 ng, confirming that this allergen can pass through the dust bag during vacuuming.

A novel method of attaching a fine mesh filter to the end of a disposable plastic pipette is described. Such a pipette filter can be used to exclude specimen uptake during specimen preparation procedures, particularly when processing small or transparent materials. The pipette filter‐tip does not interfere with fluid exchange and is non‐reactive with normal processing fluids. 1994 Blackwell Science Ltd

A method is presented which allows the quantification of the effects of chemotactic factors on polymorphonuclear leukocytes on the basis of a sensitive ATP measurement using bioluminescence. The assay measures those cells which have migrated through a commercial 3 micron filter system (Transwell). The assay was tested under standardized conditions with different chemotactic agents (leukotriene B4 [LTB4], N-formyl-methionyl-leucyl-phenylalanine [FMLP], N-formyl-methionyl-leucyl-phenylalanine-methyl ester [M-FMLP]). Under appropriate conditions the migration of PMN-cells is time-dependent and linear for 60 minutes. Spontaneous migration of PMN cells is simultaneously quantified in a simple way, and the value obtained allows a determination of the actual chemotactic situation of the PMN cells. In healthy humans the spontaneous migration varied between 4.2% and 14.4% of the total number of PMN cells. An optimal chemotactic activity was detected at 10(-8)/mol/l for FMLP and 10(-7) mol/l for M-FMLP in PMN leukocytes, which correlates with literature values. It was also found that in contrast to EDTA blood, heparinized blood lowers the ATP level of PMN cells (by about 50%) and therefore heparinized blood is not recommended for chemotactic experiments. This assay is a simple tool for quantification of the spontaneous migration, and the chemotactic response to specific factors and their inhibitors in particular for pharmacological experiments. In contrast to the 'classical' chemotactic assays this method also permits the simultaneous testing of the influence of chemotactic substances on cellular ATP levels.

Different sound processing strategies are used in the various cochlear implant designs. This report presents auditory data on 35 patients implanted at the University of Utah from April 1984 to April 1989. A multichannel monopolar electrode system is inserted intracochlearly. During daily use and auditory performance testing, four electrodes receive simultaneous input. The incoming acoustic signal is amplified and routed to the different electrodes through a band-pass filter system. Mean pure-tone performances were: 500 Hz-29.6 +/- 9.4 dB; 1000 Hz-23.5 +/- 13.2 dB; 2000 Hz-25.4 +/- 9.6 dB; 4000 Hz-32.1 +/- 11.5 dB; and 6000 Hz-42.2 +/- 7.7 dB. Audio-only CID sentence testing showed 51.4% of patients scoring better than 60% and 40% scoring better than 80%. The percutaneous pedestal is well tolerated; patients have had the systems in place for 13 and 15 years.

Um einen optimalen Korrosionsschutz im Automobilbau gewahrleisten zu konnen, ist neben den dort heute schon intensiv gepruften Vorbehandlungs- und Lackschutzeigenschaften auch eine Kontrolle der eingesetzten Feinbleche auf ihr Korrosionsverhalten notwendig. Im Hinblick auf eine kontinuierliche Blecheingangskontrolle ist eine „on-line” Prufung anzustreben. Durch reflexionsspektroskopische Messungen im sichtbaren Wellenlangenbereich kann gezeigt werden, das die Erfassung der Zusammensetzung und Dicke der atmospharisch gebildeten Oxidschicht auf der Blechoberflache cine Vorhersage des Korrosionsverhaltens von beschichteten Blechen gestattet. Hierbei ist es ausreichend, die Remissionswerte mit einem einfachen Dreifiltergerat bei ausgewahlten Wellenlangen zu bestimmen. Zusammen mit dem aus weiteren Untersuchungen angefallenen Datenmaterial werden die verschiedenen Mesgrosen mittels der Faktorenanalyse auf ihre Korrelation zu Freibewitterungsergebnissen untersucht. Determination of the corrosion behaviour of car-body steel by optical methods For optimum corrosion protection in car manufacturing it is of importance to test the corrosion properties of the low carbon steel in addition to the quality of the surface coating. For this purpose it is necessary to apply methods which can be used on-line as it is the case by reflectance spectroscopy. The composition and the thickness of the oxide layer on the steel can be determined by analyzing the spectral absorption of the oxide layer. It is sufficient to detect the intensity of the reflected light at three different wave-lengths by a filter system. From these intensities a corrosion index can be calculated with a high correlation to the corrosion under paint. Various data from other investigations will be presented and analyzed by factor analysis.

Elektroniederschachtofen sind bei der Herstellung von Calciumcarbid, Ferrolegierungen, Silicium und Silicium-Legierungen im Einsatz. Bei diesen Reduktionsprozessen mussen grose Mengen an heisen, staubbeladenen Abgasen abgefuhrt und gereinigt werden. Die Staubquellen und die Entstaubungssysteme werden beschrieben, fur die Auswahl von filternden Abscheidern werden Hinweise gegeben. Die Aufwendungen fur die Entstaubung von Elektro-Reduktionsofen konnen durch Nutzung der in den Abgasen enthaltenen Energie vermindert werden. Allerdings sind die fur die Abwarme-Ruckgewinnung notwendigen Investitionen zur Zeit noch unwirtschaftlich. Dust collectors for submerged electric arc furnaces. Submerged electric arc furnaces are installed for the production of calcium carbide, ferro alloys and silicon. In these reduction processes large quantities of hot, dust-loaded fumes must be withdrawn and cleaned. The dust sources and the air pollution control systems are described; suggestions for the selection of dust collectors are made. The costs for the filter system in electric reduction furnaces can be reduced by exploiting the energy contained in the fumes. The investments, however, which are required for heat recovery are at present not yet economical.

A FILTER system may be divided into three major parts, each of which jlJl is fundamental and essential to the successful operation of the unit as a whole: (1) the strainer or underdrain system, (2) the layer proper or medium for filtration, and (3) the reconditioning or wash system. A filter is intended to filter or clarify a definite volume of water or solution in a definite time at a definite unit area rate. This rate has been more or less accepted by water works engineers to be 2 gpm. per sq.ft. for ordinary gravity filters. Recently, however, there have been tendencies to increase this by 50 per cent with little change in design. A properly treated water is assumed for the successful operation of any filtration plant, leaving only the three elements for discussion, namely, strainer, filter body and wash system.

An effective method of marine filtration applicable to fast flow recirculating aquarium systems is described. The filtering apparatus consists of a sealed disc assembly utilizing poly-propylene fabric as filtering matrices. At circulation rates of 190 liter/min, 97% of suspended material (unicellular organisms, volume range of 376 - 1030 cubic microns is removed in 24 hr. Absolute filtration is achieved at an approximate particle volume of 1500 cubic microns. Lifetime of the poly-propylene matrix exceeds 60 days in combination with techniques to insure stable chemical consistency of circulated sea water. (Author)