bluuebunny/crossref_metadata_2025_split huggingface dataset:
Durability of Galvanized Steel in Concrete
Authors: Treadaway KWJ , Brown BL , Cox RN 
Published: March 2009

Two major exposure site programs have been undertaken to provide comparative information on the corrosion susceptibility of steel in concrete. In the first (current for 14 years), a comparative examination of the performance of zinc-coated and uncoated mild steel in a range of concretes made with both dense and lightweight pulverized fuel ash (pfa) aggregates has been made. In the second (which has been underway for five years and where corrosion has been accelerated by the addition of calcium chloride to the concrete), evaluation of the performance of galvanized steel (in this case on a substrate of high-yield bar) has been supplemented by studies of American Iron and Steel Institute (AISI) Types 405, 430, 302, 315, and 316 stainless steel bar and a comparison with the performance obtained from high-yield deformed bar. Both programs have employed exposure of small reinforced concrete prisms in which the concrete cover to the reinforcement has been carefully set by locating the test specimens on a supporting frame. In the five-year tests, the prism specimens have been augmented with trials on reinforced beams which have been stressed to give cracks in the concrete cover to the steel.
This paper discusses the results obtained from the galvanized steel specimens and compares them with those for the untreated steel examined in these studies. The results can be divided into a number of categories. Similar good performance (in terms of cracking of the cover induced by expansive corrosion of the reinforcement) has been exhibited by mild, high-yield, and galvanized steel in dense-aggregate good-quality chloride-free concrete. Where dense aggregate has been substituted by lightweight aggregate, cracking due to corrosion of the unprotected steel occurred at low cover, whereas identical prisms containing galvanized bars remained uncracked. The addition of high levels of calcium chloride (3.0 percent by weight and above with respect to the cement) to the dense-aggregate concrete caused severe corrosion of the high-yield bar and resulted in massive cracking of the cover. To date, this cracking has been less severe in similar specimens reinforced with galvanized steel, but results of weight loss measurement indicate extensive zinc loss in some specimens. However, much less loss of zinc has been measured on bars removed from concrete made without deliberate addition of chloride and from concrete to which up to 1.5 percent calcium chloride (by weight of cement) has been added. In the more permeable mixed without added chloride, where carbonation has reached the test bar, plain steel has corroded, resulting in cracking of the cover, whereas with galvanized bar some zinc loss has occurred but without fracture of the cover. The results suggest that, although some delay in cracking of the cover is achieved by the use of galvanized reinforcement, the greatest benefit would occur where it has been used in low-quality relatively permeable concrete containing low or minimal quantities of chloride.
Critique of Testing Procedures Related to Measuring the Performance of Galvanized Steel Reinforcement in Concrete
Authors: Cornet I , Bresler B 
Published: March 2009

Laboratory investigations of the corrosion performance of galvanized steel and of black steel in concrete show inconsistencies, poor correlation between field performance and accelerated laboratory tests, and even a lack of theoretical justification and understanding of modeling principles in testing.
This critique examines factors which influence the relationships between test results and prototype performance: loading, environment, geometry, and materials. Laboratory investigations of corrosion of black and of galvanized steel in concrete are reviewed. Bond characteristics, ductility, strength, and fatigue strength of galvanized reinforcement are presented. Field performance is discussed.
Emphasis is placed on planning of field and laboratory tests. Four primary requirements are proposed: structural integrity, functional integrity, durability, and aesthetic appearance. There are no standardized or widely accepted test procedures to evaluate corrosion performance of reinforcing or prestressing steel in concrete exposed to aggressive environments.
Microchannel X-Ray Image Intensifiers
Authors: Chalmeton V 
Published: March 2009

The construction and working principles of a microchannel and the characteristics of channel plates are briefly described. X-ray image intensifiers can be built by use of this electronic multiplier with an X-photon-electron converter, and a conventional phosphor screen for the output. Three main types are considered: the scintillation image intensifier, the metallic converter image intensifier, and the direct-detection image intensifier. The description and the main characteristics are given for each type of intensifier.
Also considered are the main limitations of microchannel image X-ray intensifiers; namely the limitations in diameter and uniformity and, for the whole system, due to the limited number of photons available which limit spatial resolution, the lifetime and the noise factor, which can also be serious drawbacks for particular intensifiers.
So, even taking into account that some interesting characteristics of microchannel plates (variable gain, no distortion, fast response) have not been fully exploited, the developments of such intensifiers, in the near future, will be probably limited to some special uses both in medical and industrial fields.
Technological improvements and reductions of price can modify, of course, the present situation in a few years.
Real-Time Computerized Fluoroscopy and Radiography—A Progress Report
Authors: Kruger RA , Riederer SJ , Houk TL , Mistretta CA , Shaw CG , Lancaster JC 
Published: March 2009

This report describes our initial experiences in the medical profession with real-time digital processing of X-ray transmission information taken from the video output of a conventional X-ray fluoroscopy and ciné fluoroscopy system. X-rays are produced with an X-ray tube operated between 45 and 100 kVp, 1 to 300 mA, and filtered by a variety of materials, the choice depending on the type of information which is to be isolated during the imaging process. The transmitted beam is detected by a cesium iodide image intensifier viewed by a television system with a lead-oxide vidicon tube.
The video signal is digitized to 8-bit accuracy every 100 ns and stored in any of three identical 256 by 256 random-access memories. Data may be temporally integrated to 13-bit gray-scale resolution. Several algorithms may be employed to process the data. All algorithms are presently dedicated hardware-based functions which were assembled in our laboratories. Although analog data may be processed from video tape, best results are achieved when image processing is performed on the original data. In the latter case the desired fully processed images appear during, or immediately after, the X-ray exposure.
Present imaging modes include (1) three-spectrum K-edge imaging of iodine, (2) time-dependent subtraction angiography using intravenous injections of iodinated contrast agents, (3) time-dependent subtraction mask mode imaging of nonopacified hearts, (4) time-derivative displays of opacified and nonopacified hearts, and (5) cardiac phase displays of nonopacified hearts. K-edge subtraction imaging of opacified hearts at rates of 30 to 60 per second is also being investigated.
Field Studies of the Air Tightness of Residential Buildings
Authors: Wang FS , Sepsy CF 
Published: March 2009

The heat loss (gain) due to air leakage becomes increasingly significant as more thermal insulation material or systems are added to a house to reduce the conductive heat loss (gain). It is quite clear that a standard energy procedure is needed whereby the housing industry and the energy agencies can practically evaluate or estimate the energy demand due to air leakage or infiltration for a new residential structure or a reinsulated existing house.
The two major techniques that have been utilized more recently to either quantify the air infiltration rate or characterize the air leakage of a house are the “tracer gas technique” and the “induced pressure technique.” The former can provide the absoluted air infiltration rate under various ambient conditions; whereas the latter can give an estimate on the relative air tightness of a house. Each one has its advantages or drawbacks in practice. However, they do compliment each other in situations where a large number of houses need to be measured.
A typical case is presented here to show that both techniques were applied to the same group of houses. The measured air infiltration rates from the tracer gas technique, and equivalent air leakage area from the induced pressure technique do show good agreement in concluding the air tightness of these houses. The existence of such air infiltration rate differences was also detected through the energy consumption test conducted among the same group. Some of the practical aspects of these two approaches are also presented.
Air Leakage Measurements by the Tracer Dilution Method—A Review
Authors: Lagus PL 
Published: March 2009

Air leakage (infiltration) represents an important part of the heating and cooling load of residential, commercial and industrial buildings. It is also an important parameter in indoor-outdoor air pollution relationships. Air leakage is difficult to quantify because it is not only a function of building tightness and configuration, but also of inside-outside temperature differences, wind speed, and of workmanship in construction. Standard formulas for calculating air leakage do exist, but they are at best rough approximations.
The tracer dilution method has been used for a number of years to infer air leakage rates. This technique entails introducing small amounts of tracer gas into a structure and measuring the rate of change in tracer concentration. The air change rate can then be determined from the exponential decay rate in tracer concentration with respect to time.
There exists no perfect or ideal tracer. Thus, the choice of tracer gas is dependent upon the characteristics inherent in the measurement, the structure being measured, and in the relative familiarity of the experimenter with a variety of experimental techniques. The various gases that have been used for performing tracer dilution measurements in the past are presented along with their methods of measurement. In addition, the basic experimental methodology for performing a tracer dilution measurement utilizing any tracer is discussed. The limitations and advantages of the method are described and recommendations for its use are made. The need for standard test methodology is explored with an emphasis on the ability to produce and provide data that can be intercompared at some later time. An uncertainty analysis of the method is provided.
Organics in Air: Sampling and Identification
Authors: Schlitt H , Knoeppel H , Versino B , Peil A , Schauenburg H , Vissers H 
Published: March 2009

Various complementary methods have been developed for the analysis of organic compounds in air, taking into account their different physicochemical and detection characteristics: 1. Gaseous hydrocarbons (boiling point range, C2 to C5) are adsorbed on a carbon molecular sieve (CMS), separated on a packed alumina column, and detected by a flame ionization detector (FID). 2. Halogenated hydrocarbons are also adsorbed on CMS, separated on a glass capillary column, and detected by an electron capture detector (ECD). 3. Other volatile organics are adsorbed on Tenax gas chromatographic adsorbent, separated on glass capillary columns, and detected by FID and a computerized mass spectrometer. 4. Aerosols are sampled on glass-fiber filters and extracted, and the extract is analyzed by a computerized gas chromatograph-mass spectrometer.
The methods are briefly described, the experiences and encountered difficulties are discussed, and some applications are shown.
Polyurethane Foam and Selected Sorbents as Collection Media for Airborne Pesticides and Polychlorinated Biphenyls
Authors: Jackson MD , Lewis RG 
Published: March 2009

Accurate information on low levels of pesticides in ambient air would aid the U.S. Environmental Protection Agency in making decisions on allowable pesticide usage. In order to accomplish routine air monitoring of pesticides sampling media capable of collecting and retaining pesticides in the range of picograms to low nanograms per cubic metre, while maintaining an air flow rate of 200 to 250 litres/min, are needed. Polyurethane foam (PUF) has been used for trapping some pesticides and industrial chemicals in the past. Also some of the solid sorbents such as Porapak R and Tenax-GC have been evaluated.
Several solid sorbents in combination with PUF were evaluated, using mixtures of either organochlorine or organophosphorus pesticides. Recoveries of these pesticides are discussed.
An evaluation of the system during a cleanup of a polychlorinated biphenyl (PCB) spill in North Carolina is discussed.
The Use of Torsion Testing to Assess Material Formability
Authors: Canova GR , Shrivastava S , Jonas JJ , G'Sell C 
Published: March 2009

The accurate conversion of the torque/twist data obtained from torsion tests into equivalent stress/equivalent strain data is required for reliable formability predictions, particularly at large strains. The first stage in this process is the derivation of the shear stress/shear strain curve from the torque/twist data. A new method is proposed which performs this first operation. It is based on the observation that the radii of cylindrical bars remain straight during testing, and also on the hypothesis that the state of the material at a given radius is not influenced by the state of the surrounding layers. This method appears to reduce significantly the errors inherent in the previous methods.
The second stage involves converting the shear stress/strain curve into an equivalent stress/equivalent strain relationship, with due consideration for the very large strains involved. For this purpose, the equivalent strain εeq is calculated from the incremental changes in the strain components during torsion. This analysis leads to the relation ϵeq=γ∕3 where γ is the shear strain at the radius of interest. This solution is the same as for small deformations, and thus conflicts with the result of Eichinger and Siebel, which is different for large strains.
It is also shown that, when the corrected conversions are used, the rate of work hardening calculated from torsion tests is lower than that obtained from uniaxial testing. This discrepancy is attributed to three causes: (a) at low strains, the torsion equivalent stresses calculated using the von Mises relationship are 6.5 percent lower than those obtained from the crystallographically based Bishop and Hill formulation, which is judged to be more accurate; (b) the difference in the textures developed in torsional and tensile deformation leads to Taylor factors that evolve differently with strain, and which cause the tension and torsion equivalent stresses to diverge at large strains, even if the true rates of work hardening (in terms of the critical resolved shear stresses) are the same in the two modes of deformation; (c) there is a possibility that there is less dislocation accumulation at large strains in torsion than in tension because less dislocation intersection is required by the torsion as opposed to the tension end textures. The lower work hardening rates determined in torsion lead in turn to lower forming limit predictions for deformation along other strain paths.
Manufacturing and Properties of Large Castings in 13Cr-1Ni Low-Carbon Steel (ASTM A217)
Authors: Santafè C , Priante M , Amici G , Finocchio M 
Published: March 2009

Previous investigations on the steel ASTM A217 (TERNI FM1M) with low carbon content have been extended by creep-rupture and stress corrosion tests. Creep test results were analyzed in order to evaluate long-term creep resistance according to the Larson-Miller method. Stress corrosion tests did not show any cracks, up to 700 h, for the applied stress of both 90 and 110 percent yield strength, but pitting phenomena were evident.
Cavitation tests were performed to evaluate the behavior of this steel for hydraulic purposes.
Results concerning the manufacture of six turbine shells for a nuclear power station, weighing about 80 metric tons at shipment, are reported.
An Investigation of Initial Fatigue Quality
Authors: Wang DY 
Published: March 2009

This paper describes an investigation to define statistical fatigue in terms of the initial quality of fastener holes. The objective is to develop and verify equivalent initial flaw size (EIFS) concepts for fatigue durability analysis of typical production quality structures.
A special test procedure was used to obtain a statistically large sample of data under spectrum loading by testing a specimen containing 24 holes. It is possible to obtain a maximum of 96 fatigue data sets in the test of two specimens up to 100 000 flights in a reasonable time. The method involved removing the early cracked holes with a circular saw cutter and continuing the testing of the remaining holes. Marker cycles, which were designed to be an integral part of the spectrum, have served the intended purpose of identifying crack origins and microcrack growth rates using scanning electron microscope (SEM) fractography. The surface mechanical and material defects responsible for the origin of microcracks were examined quite fully.
Through quantitative analysis of a large amount of microcrack growth data and surface macrocrack growth data, many parameters affecting apparent fatigue scatter were resolved. A method was developed to define statistical fatigue quality of fastener holes in terms of EIFS distribution. The EIFS should be a function of initial surface quality and independent of other secondary variables that affect crack growth rate. The procedure involves the use of a master crack growth curve developed from the experimental data of microcrack growth ranging from initial physical flaws as small as 0.005 mm (0.0002 in.). The essential physical defects in 2024-T3 as origins of microfatigue cracking are the tool marks and inclusions.
Factors Influencing Propagation of Mode III Fatigue Cracks under Torsional Loading
Authors: Hurd NJ , Irving PE 
Published: March 2009

Mode III fatigue crack growth rates have been measured in a quenched and tempered low-alloy steel heat treated to a range of strength levels. When compared with Mode I crack growth rates, it is found that Mode III rates are slower than the Mode I by a factor of between 10 and 50. ΔKT-values in Mode III are believed to be much larger than those of Mode I.
The stability of Mode III cracks compared with those in Mode I is shown to be related to applied ΔK, R-ratio, and the strength level of the steel. Mode III cracks are most stable in tests at R = −1, at high values of ΔK, and in the softest material. These conclusions are in part related to the differences between Mode III and Mode I crack growth rates. The results are considered in the light of surface hardening treatments applied to shafts loaded in torsion.
Prediction of Fatigue Crack Growth under Variable-Amplitude and Spectrum Loading Using a Closure Model
Authors: Newman JC 
Published: March 2009

The present paper is concerned with the application of an analytical crack-closure model in the study of crack growth under various load histories. The model was based on a concept like the Dugdale model, but modified to leave plastically deformed material in the wake of the advancing crack tip.
The model was used to correlate crack growth rates under constant-amplitude loading, and to predict crack growth under variable-amplitude and aircraft-spectrum loading on 2219-T851 aluminum alloy sheet material. Predicted crack-growth lives agreed well with experimental data. For 80 crack growth tests subjected to various load histories, the ratio of predicted-to-experimental lives, NP/NT, ranged from 0.5 to 1.8. The mean value of NP/NT was 0.97 and the standard deviation was 0.27.
Strength of Compacted Specimens of a Calcareous Playa Lake Clay
Authors: Olsen JM , Leonard BD 
Published: March 2009

This paper presents the results of a series of tests run on specimens of a low-plasticity clay (LL = 34, PI = 12) with a calcite content of approximately 25 percent by weight. The naturally occurring clay tested is from playa lake deposits in southern Idaho. This test program investigated the strength of labratory compacted specimens as a function of time and curing conditions.
Specimens of 33.3 mm (1.3 in.) diameter were prepared using the Harvard miniature kneading compaction device. Specimens for strength testing were prepared with water contents at optimum (16.5 percent) and 4.5 percent dry of optimum (12 percent). The latter value is approximately the water content of the material as-sampled. After compaction, specimens were allowed to cure under either air-dry or moist conditions prior to strength testing. The unconfined strength [ASTM Tests for Unconfined Compressive Strength of Cohesive Soil (D 2166-66)] of replicated specimens was measured at times ranging from several minutes to three months after compaction.
The results of these tests showed substantial strength gain with loss of moisture. Most of the increase in strength was experienced within the first 8 h of air-drying while the increase was more gradual for the moist cured specimens. The specimens compacted at optimum water content exhibited higher strengths than those compacted dry of optimum after curing. In the as-molded condition, however, the dry-of-optimum specimens were stronger.
CAUS-1 (Computer-Aided Ultrasonic System)
Authors: Doherty JE , LaGrotta JM , Burr RJ , Wheeler E 
Published: March 2009

This paper reports on the construction of a computer aided ultrasonic inspection system (CAUS-1) which does not require inspection shapes to have premachined rectilinear surfaces nor the large material overstock needed by conventional inspection methods.
The main features of CAUS-1 include a contour sensing-following system, computer controlled ultrasonic instrumentation, and flexible software package. The contour following system maintains the inspection beam normal to the inspection surface and enables dimensional measurement of the shape simultaneously with ultrasonic inspection. The ultrasonic instrumentation can resolve a number one flat bottom hole (FBH) 2 mm from the front surface and through 35 mm of material using a single instrument setting. The instrument has a special defect gate that reports the magnitude and position of the two largest indications detected by each ultrasonic pulse. A knowledge of computer programming is not needed in order to use CAUS-1, because inspection procedures are developed interactively using English language. The software contains data analysis features for process control inputs, inspection data archival storage, dimensional inspection, and a method of inputting shape data into a computer aided machining system (CAM).
CAUS-1 is a fully integrated inspection system that can inspect near-net shapes for material defects and dimensional tolerance in a quarter of the time it takes to inspect a disk for material defects alone using conventional inspection methods.