Calibration of weirs by means of critical flow and specific energy

For many years man has been relying more each day upon metering devices to measure the flow of fluids in industry. The orifice, orifice meter, venturi meter, pitot tube, nozzle, flume and the weir have been employed, each having its own particular advantage. In this parade of metering progress, the contracted weir has long been the forgotten brother of the suppressed weir. In almost every textbook on hydraulics or fluid mechanics, the following words appear, end contractions are to be avoided where the weir cannot be calibrated . This skepticism and the length or absurdity of some contracted weir formulas led to the development of this study --Introduction, page 1

A History of the Pacific Northwest District Conference of the Evangelical Free Church of America

The Evangelical Free Church of America is a merger. It should be noted that the Free Church groups that merged in 1950 to form the Evangelical Free Church of America, each had early beginnings in the Northwest. The first Free Evangelical witness in the Pacific Northwest occurred in the decade of the 1880s, following the historic meetings of organization at Boone, Iowa, and Boston, Massachusetts in 1884. The first churches of both the Swedish and Norwegian-Danish groups were centered in the Seattle-Tacoma area. Progress and growth were impeded in those early days by language and distance barriers. By the time that the language change was nearly completed in the year 1935, the Swedish group had three organized congregations and the Norwegian-Danish. group had four. By the time of the merger in 1950, both groups had grown appreciably. The Swedish group had added nine churches, the Norwegian-Danish group eight

Chromium and Reactive Element Modified Aluminide Diffusion Coatings on Superalloys: Environmental Testing

The isothermal oxidation of reactive element (RE)-doped aluminide coatings on IN 713LC alloy substrates at 1100 ˚C in air formed a continuous slow-growing α-Al2O3 scale after 44 h of exposure. RE-free (reactive element-free) aluminide coatings were characterized by a cracked oxide scale which exposed an underlying voided coating surface. The cyclicoxidation behavior of Cr/RE-modified aluminide diffusion coatings on René 80 and IN 713LC alloy substrates, and of RE-doped aluminide coatings on IN 713LC alloy substrates, at ll00~ in static air was determined. Coatings deposited by the above pack (AP) arrangement, as opposed to the powder contacting (PC) arrangement, showed improved resistance to cyclic oxidation attack. RE-doped and Cr/RE-modified aluminide coatings exhibited considerably more adherent protective Al2O3 scales compared to undeped aluminide coatings. The hot corrosion behavior of Cr/RE-medified aluminide coatings on René 80 and Mar-M247 alloy substrates at 900~ in a 0.1% SO2/Q gas mixture also was determined. The Cr/RE-modified aluminide coatings provided better resistance to hot corrosion attack (i.e., thin film studies) than a commercial low activity aluminide coating. Coating lifetimes were strongly dependent on the chromium surface composition, since a mixed (A1, Cr)2O3 scale better resists attack by the molten salt

Chromium and Reactive Element Modified Aluminide Diffusion Coatings on Superalloys: Environmental Testing

The isothermal oxidation of reactive element (RE)-doped aluminide coatings on IN 713LC alloy substrates at 1100 ˚C in air formed a continuous slow-growing α-Al2O3 scale after 44 h of exposure. RE-free (reactive element-free) aluminide coatings were characterized by a cracked oxide scale which exposed an underlying voided coating surface. The cyclicoxidation behavior of Cr/RE-modified aluminide diffusion coatings on René 80 and IN 713LC alloy substrates, and of RE-doped aluminide coatings on IN 713LC alloy substrates, at ll00~ in static air was determined. Coatings deposited by the above pack (AP) arrangement, as opposed to the powder contacting (PC) arrangement, showed improved resistance to cyclic oxidation attack. RE-doped and Cr/RE-modified aluminide coatings exhibited considerably more adherent protective Al2O3 scales compared to undeped aluminide coatings. The hot corrosion behavior of Cr/RE-medified aluminide coatings on René 80 and Mar-M247 alloy substrates at 900~ in a 0.1% SO2/Q gas mixture also was determined. The Cr/RE-modified aluminide coatings provided better resistance to hot corrosion attack (i.e., thin film studies) than a commercial low activity aluminide coating. Coating lifetimes were strongly dependent on the chromium surface composition, since a mixed (A1, Cr)2O3 scale better resists attack by the molten salt

Chromium and Reactive Element Modified Aluminide Diffusion Coatings on Superalloys: Environmental Testing

The isothermal oxidation of reactive element (RE)-doped aluminide coatings on IN 713LC alloy substrates at 1100 ˚C in air formed a continuous slow-growing α-Al2O3 scale after 44 h of exposure. RE-free (reactive element-free) aluminide coatings were characterized by a cracked oxide scale which exposed an underlying voided coating surface. The cyclicoxidation behavior of Cr/RE-modified aluminide diffusion coatings on René 80 and IN 713LC alloy substrates, and of RE-doped aluminide coatings on IN 713LC alloy substrates, at ll00~ in static air was determined. Coatings deposited by the above pack (AP) arrangement, as opposed to the powder contacting (PC) arrangement, showed improved resistance to cyclic oxidation attack. RE-doped and Cr/RE-modified aluminide coatings exhibited considerably more adherent protective Al2O3 scales compared to undeped aluminide coatings. The hot corrosion behavior of Cr/RE-medified aluminide coatings on René 80 and Mar-M247 alloy substrates at 900~ in a 0.1% SO2/Q gas mixture also was determined. The Cr/RE-modified aluminide coatings provided better resistance to hot corrosion attack (i.e., thin film studies) than a commercial low activity aluminide coating. Coating lifetimes were strongly dependent on the chromium surface composition, since a mixed (A1, Cr)2O3 scale better resists attack by the molten salt

Thermochemical Degradation Mechanisms for the Reinforced Carbon/Carbon Panels on the Space Shuttle

The wing leading edge and nose cone of the Space Shuttle are fabricated from a reinforced carbon/carbon material (RCC). The material attains its oxidation resistance from a diffusion coating of SiC and a glass sealant. During re-entry, the RCC material is subjected to an oxidizing high temperature environment, which leads to degradation via several mechanisms. These mechanisms include oxidation to form a silica scale, reaction of the SiO2 with the SiC to evolve gaseous products, viscous flow of the glass, and vaporization of the glass. Each of these is discussed in detail. Following extended service and many missions, the leading-edge wing surfaces have exhibited small pinholes. A chloridation/oxidation mechanism is proposed to arise from the NaCl deposited on the wings from the sea-salt laden air in Florida. This involves a local chloridation reaction of the SiC and subsequent re-oxidation at the external surface. Thermodynamic calculations indicate the feasibility of these reactions at active pits. Kinetic calculations predict pore depths close to those observed

Pulmonary Microembolism in the Canine Model: Report of a Pilot Study

Use of in-line final filters to prevent the infusion of foreign particulates has lowered the rates of postinfusion phlebitis in several controlled studies. The systemic effect of particulate infusion, however, has not been thoroughly studied. In this study, 12 mongrel dogs recovering from a right pneumonectomy were studied following infusion of various-sized particulates. Ten of the dogs were infused with either 10 or 40 million, 9 or 25 μm, latex particles. The remaining two dogs were control animals. Hemodynamic parameters were monitored in each animal. At death or 72 hours following particle injection, the left lung was examined grossly and histologically. Changes in hemodynamic parameters were not seen. Three of the dogs became clinically ill 48 hours following microsphere injection. All dogs injected with particles had multiple discrete punctate areas of hemorrhagic pulmonary infarction. The control dogs showed no sign of clinical illness or pulmonary injury. More sophisticated animal and human studies are required to fully determine the physiologic effect of injected particles

Multiple Function Intubation Apparatus and Method

An apparatus and its method of use are provided allowing lavage, sump and enteral feeding operations with only one intubation. The apparatus includes a first tube having two distinct passageways. One of these passageways completely contains a second, feeding tube during intubation. Once the first tube is in place in the patient, the second tube is extended from the first tube so as to enter the stomach. The extension of the second tube opens ports in the first passageway of the first tube, thereby allowing sump or lavage treatment with the second passageway of the first tube serving as an air vent. A constriction in the end of the first passageway engages a band on the proximal end of the second tube to keep the tubes together. Once gastric emptying of the patient resumes, the second tube immediately moves into the duodenum then into the jejunum past the Ligament of Treitz and the first tube is withdrawn from the patient while maintaining the second tube in position for enteral feeding through feeding ports in its distal end

Oxidative Attack of Carbon/Carbon Substrates through Coating Pinholes

A critical issue with oxidation protected carbon/carbon composites used for spacecraft thermal protection is the formation of coating pinholes. In laboratory experiments, artificial pinholes were drilled through SiC-coatings on a carbon/carbon material and the material was oxidized at 600, 1000, and 1400 C at reduced pressures of air. The attack of the carbon/carbon was quantified by both weight loss and a novel cross-sectioning technique. A two-zone, one dimensional diffusion control model was adapted to analyze this problem. Agreement of the model with experiment was reasonable at 1000 and 1400 C; however results at lower temperatures show clear deviations from the theory suggesting that surface reaction control plays a role