bluuebunny/crossref_metadata_2025 huggingface dataset:
Bolt Hole Growth in Graphite-Epoxy Laminates for Clearance and Interference Fits When Subjected to Fatigue Loads
Authors: Kam CY
Published: March 2009

This paper presents the results of an experimental program that was conducted to evaluate the damage to the bolt hole as related to the fit of the bolt to the hole in the graphite-epoxy laminate when the joint is subjected to a fatigue load spectrum. The experimental program was conducted using a double-lap bolted-joint test specimen. Three types of bolt fit were used in the experiment: interference fit, clearance fit, and clearance fit with wet sealant. The bolts were torqued to values representing standard installation torque. The graphite-epoxy laminate used for the test specimens was pseudoisotropic laminate of (0/90, ±45)4S. The prepreg was T300/5208 and the laminate was cured in the standard Narmco 5208 cure cycle.

The test program consisted of applying cyclic loadings to produce bearing stress levels of 397 × 106 N/m2 (+57 600 psi) for 50 000, 100 000, 200 000, and 500 000 cycles. The bolted specimens were disassembled and the bolt hold diameters measured for hole growth. Preliminary results indicated that hole growth will occur when the bearing stresses are above 50 000 psi. Bolts installed in clearance holes with the PR1422 sealant had the same hole growth as bolts installed without the sealant.
Fatigue Behavior of Graphite-Epoxy Laminates at Elevated Temperatures
Authors: Rotem A , Nelson HG
Published: March 2009

The fatigue behavior of multidirectional graphite-epoxy laminates is examined and analyzed in terms of the single lamina behavior. The nonlinear viscoelastic moduli of the epoxy matrix are changed with temperature and thus the characteristics of the laminae are altered. As a result, the static and fatigue strengths of a laminate are changed due to the redistribution of the stress field in the laminate and the weakening effect of temperature on the matrix. The fatigue behavior of a single lamina is characterized by its static strength and its “fatigue function” that expresses the degradation in the strength of the lamina due to cyclic loading. The effect of temperature is introduced through the use of “shifting factors” for both the static strength and the “fatigue function.” The laminate strength is predicted by considering the cyclic stress field in each lamina, the interlaminar stresses, and the experimentally determined shifting factors. The first failure of a lamina in a laminate is examined first in terms of stress redistribution and second in terms of total failure and final laminate fracture. The analytically determined results are compared with the actual fatigue behavior of many T300/5208 graphite-epoxy composite laminates. The experimental results are shown to be in good agreement with the theoretical predictions. The temperature “shifting factors” enable one to predict long-term behavior at some temperature from short-time testing at elevated temperatures.
Load Sequence Effects on the Fatigue of Unnotched Composite Materials
Authors: Yang JN , Jones DL
Published: March 2009

A comprehensive version of a fatigue and residual strength degradation model previously developed by the authors is proposed. This theoretical model is capable of predicting the statistical distributions of the fatigue life and the residual strength as well as the effect of load sequence, under variable amplitude or spectrum loadings, on these distributions. The model has been verified by the use of existing test data on glass/epoxy laminates. It is shown that the correlation between the model and the test results is good.
Application of Laboratory Scale Model Streams Toward Assessing Effluent Impacts in Freshwater Lotic Environments
Authors: Russell PP , Horne AJ , Thomas JF
Published: March 2009

Laboratory scale model streams were developed to assess the effects of oil-shale-related effluents on aufwuchs. The model stream design allowed variation of water temperature, chemical composition, flow rate, and illumination intensity and periodicity. Chemical constancy of the stream water was provided by continuously metering new water to the streams with doses of test effluents. Omega-9 water, the experimental retort water used, was studied at dilutions between 0.013 and 2.12 percent for 9 days. Day 3 samples generally showed stimulated growth at all dilutions. Measurements on Days 6 and 9 however, had lowered levels of growth at 1 percent or more Omega-9 water concentration. The more dilute effluent loads stimulated growth throughout the test period. The most marked effect of Omega-9 water was to lower the proportional contribution of diatoms to the aufwuchs biomass. Measurements of control model streams suggest a species composition heterogeneity of 10 to 15 percent with a total unloaded stream spatial/temporal variability of no greater than about 25 percent. The biomass measurements were very reproducible, but chlorophyll a and respiration rate assays were hampered by excessive analytic error. Field confirmation of these tentative results is strongly recommended.
Establishment of Biotic Communities Within a Newly Constructed Ash Settling Basin and Its Drainage System
Authors: Guthrie RK , Cherry DS , Davis EM , Murray HE
Published: March 2009

A newly constructed coal-ash settling basin and its drainage system at the 400D area power plant of the Savannah River Project, in Aiken, S.C., were studied from April 1977 to December 1978. The basin was filled in August 1977 by a flow of 7500 litres/min that consisted of Savannah River water and coal ash. The effluent was released to an excavated canal approximately 300 m in length, which drained into an older stream (300 m long) and then into a 3-km2 swamp area that had received effluent from a previous ash settling basin. Between March and August 1977, the stream and swamp received only runoff from rainfall. During this time, when no basin effluent was released to the stream and swamp, the water quality characteristics were altered, and aquatic biota were reduced throughout the system.

The water quality characteristics were tested in the new ash settling system approximately every two months between April 1977 and December 1978. Samples were collected to determine the aerobic bacterial, phytoplankton, zooplankton, benthic invertebrate, and vertebrate populations at five stations in the basin system and one in the Savannah River at the pump station.

During the period of study, there were no major changes in water quality characteristics within the new basin. Seasonal peaks occurred in the bacterial populations in warmer months, and the composition of those populations within the basin system was determined to be different from that in the Savannah River. Sparse planktonic populations within the basin increased in numbers and diversity as the basin stabilized. Benthic invertebrates were first collected in the new basin in December 1977 and then increased in density and diversity at each subsequent sampling. Tadpoles were first collected in the basin in April 1978, and mosquito fish were first collected in May 1978.

Data obtained indicate that an efficient settling basin for coal ash has provided a suitable habitat for varied aquatic biotic communities, although some characteristics of the effluent have affected the normal balance and stability of communities within this environment. Such findings are important in that the suitability of receiving water habitats to aquatic life should be little affected by the release of effluent from such a basin.
Physical and Chemical Behavior and Environmental Acceptability of Stabilized Scrubber Sludge and Fly Ash in Seawater
Authors: Duedall IW , Roethel FJ , Seligman JD , Oakley SA , Parker JH , O'Connors HB , Woodhead PMJ , Roberts BK , Mullen H , Chezar B
Published: March 2009

Flue gas desulfurization sludges and fly ash pose a major disposal problem for coal-burning power plants. Disposal of stabilized, blocklike forms of these wastes in the ocean in the form of a reef is an alternative being studied at the Marine Sciences Research Center, Stony Brook, N.Y.

In laboratory experiments, physical integrity studies and components species leaching rates indicate that, in general, stabilization was found to maintain the strength of the blocks and minimize trace metal leachings in aerobic seawater over prolonged exposure.

In field studies, which are in progress, nine blocks (0.028 m3) of stabilized scrubber sludge and fly ash were placed in approximately 6 m of water in Conscience Bay near Long Island Sound. Within 3 weeks after placement of the coal waste reef and the control structure, a heavy crop of attached plants and animals were observed growing on both reefs. The organisms attached to the coal waste reef showed no elevation in heavy metals in relation to the heavy metal composition of organisms attached to the concrete control.
Offshore Filtration Testing and Analysis of Seawater for Oil-Field Injection
Authors: Cappi JB , Blagden HR
Published: March 2009

A high rate media-type filter developed for water injection applications has been tested on a 4000 BWPD (barrels of water per day) pilot plant to gather data on water quality achievable on equipment practical for offshore oil production installations. This work has been spread over 13 offshore locations around the world in seven different seas that represent a wide variety of water types, levels of suspended solids, temperatures, and depths.

The test procedures and analytical techniques used on these trials are described together with the filtering characteristics of various seawaters. Analysis included Coulter Counting, core testing, millipore tests, gravimetric, turbidity, and residual chlorine.
Monitoring Acrolein in Naturally Occurring Systems
Authors: Kissel CL , Brady JL , Guerra AM , Meshishnek MJ , Rockie BA , Caserio FF
Published: March 2009

Acrolein is an important biocide and sulfide scavenger for oil-field systems. Acrolein monitoring procedures usually involve both concentration and performance determinations. These procedures can provide useful information only when meaningful methods are employed.

Acrolein concentrations may be determined analytically by derivatization methods such as m-aminophenol fluorescence and dinitrophenylhydrazine colorimetry. Derivatization methods can be used only in special situations because numerous interferences are usually present. Direct analytical methods such as ultraviolet spectroscopy and differential pulse polarography are generally more useful. An analytical method should be used only after careful studies have shown it to be reliable, suitable, and parallel to the desired performance in the given application.

In most cases, monitoring acrolein is best done by determining its performance in each specific application. When used as a biocide, acrolein is more accurately evaluated by standard American Petroleum Institute (API) procedures than by present adenosinetriphosphate (ATP) methods. Growth in aerobic plates and anaerobic culture tubes is normally absent at typical use concentrations even though ATP readings generally register low kills. Acrolein appears to alter the mechanism of light emission by ATP.

When used to scavenge sulfides, acrolein performance is best evaluated by a sulfide specific ion electrode, because results can be misleading when determined by lead or methylene blue colorimetry. This conclusion was obtained when colorimetric methods were compared with the data from sulfide specific ion electrode determinations calibrated against lead perchlorate titrations.
Instrumented Impact Measurements on Some Polymers
Authors: Rieke JK
Published: March 2009

Instrumented impact of polymeric materials as a function of temperature and in sheet form is a useful tool for characterizing the toughness behavior of the materials in end-use applications.

The methods employed are fast and provide more information than do the classical determinations such as the Izod and Gardner impact tests. Examples of how the load-time and energy-time traces can be used in conjunction with temperature studies to determine ductile-brittle transition behavior will be illustrated.

In addition, the effect of fabrication and flow patterns on impact response and the effect of specimen thickness on impact are discussed.
The Need for More Descriptive and Meaningful Physical Data on Plastic Materials
Authors: Pang FS , Isaacs JL
Published: March 2009

During the past few years, plastics have become the major structural materials for most of the new small electrical appliance products. Thus, when the decision is made to develop a new product, a plastics material screening process will be followed, where a list of material performance requirements (processing included) will be generated, based on the expected product performance, and then matched with currently available commercial grades of plastics.

Unfortunately the plastic material physical data furnished by the supplier are not adequate. They are either too general, use wrong sample preparation method, or do not give a meaningful description of the plastic material properties from processing to end-product performance. The new General Electric plastic iron and drip coffeemaker products are two typical examples which are used to illustrate that there is a definite need for making available to the end user more descriptive and meaningful physical performance data.
International Activities of Committee A-9
Authors: Weston PL
Published: March 2009

The International Organization for Standards (ISO) was formed in 1949 to establish organizational working procedure and working groups to formulate international test standards for materials. In this work national government agencies have contributed largely to the ISO program (one notable exception being the United States.) Recent expansion has been in product performance, air quality, and reference materials. The ISO is organized via a council formed by three elected officers and 14 member organizations. An executive committee handles administrative duties and a general assembly of all member organizations is the working body. An appointed Secretary-General is the chief executive of ISO. A plenary meeting held every three years constitutes the ISO working meeting.

ISO standards are originated as working documents from a small working group or task group. Upon approval by a subcommittee the document becomes a draft proposal and is given an identification number. After approval by the technical committee, the proposal becomes a draft international standard (DIS). This document is published as an international standard after ratification by 75 percent of the general assembly voters. At present there are 160 active ISO technical committees, 550 subcommittees and over 1000 working groups or task groups. The ferroalloys technical committee (TC 132) functions in three subcommittee areas: SC-1 Sampling, SC-2 Chemical Analyses, and SC-3 Specifications. As of 1980, twenty-seven proposed standards for ferroalloys are in various stages of development.
Ferroalloys in the 80's
Authors: Deeley PD
Published: March 2009

The paper presents a review of recent user requirements for ferroalloys, and of our understanding of their metallurgical properties. Particular attention is given to alloy density, solution processes, and thermal effects. Alloy addition processes are reviewed, with major emphasis on ladle injection technology. Future developments are analyzed in light of recent and current trends.
Controlling Quality of Ferroalloys and Alloying Additives in the Manufacture of Nickel Alloys for Nuclear Applications
Authors: Stryker RS
Published: March 2009

Nickel alloys supplied to the nuclear industry must meet strict requirements for quality and traceability of constituents. Ensuring that end products meet those requirements involves careful control of the raw materials used in melting the alloys. Especially important is an effective system of quality control for purchasing and consuming ferroalloys and alloying additives. Development and operation of such a system requires (1) adequate specifications, (2) good relations with suppliers, (3) an approved-suppliers list, (4) formal receiving inspection, and (5) backup surveillance during processing.
The Role and Use of Aluminum in Steel Production
Authors: Larsen GG
Published: March 2009

Aluminum is very important in controlling steel oxidation level. As a result it also controls the ingot structure and hence the steel properties. This paper discusses the various types of aluminum used in steel production. The recovery of aluminum as a function of steel type and carbon level as well as the importance of consistent recovery are also discussed.
Additives to Steel and Iron for Improved Machinability
Authors: Peters AT
Published: March 2009

The properties required from free machining steels are machinability and surface finish; detrimental effects are the products of deoxidation. This paper describes the difficulties involved in producing high-carbon or continuously cast free machining steels, and the reasons for the virtual absence of free machining irons. Sulfur and lead as machinability promoters of steels, and the importance of the manganese/sulfur ratio, are considered, along with the forms available, manner of usage, recoveries, and recoveries from remelting scrap. The following topics are also discussed: ASTM specifications; phosphorus and nitrogen as chiefly surface finish promoters; manner of manufacture of ferrophosphorus and its properties and trends as affecting the steelmaker; products available, manner of usage, and recoveries from remelting scrap; nitrided alloys and their ASTM standards, manner of usage, recoveries, and recoveries from remelting scrap; selenium and tellurium as machinability enhancers; and possible future trends in the development of alloys for free machining steels.
Potential and Strain-Rate Effects in Slow Strain-Rate Stress Corrosion Cracking of Type 304 Stainless Steel in 35 Percent Magnesium Chloride at 120°C
Authors: Kessler KJ , Kaesche H
Published: March 2009

Constant extension rate experiments have been performed on Type 304 stainless steel round tension-test specimens in 35 percent magnesium chloride at 120°C as a function of electrode potential and extension rate. When potentiostatic measurement was applied, an extension rate of 4.4 × 10−6 s−1 was found to be acceptable as an accelerated test. These tests are compared with constant load measurements by variation of the electrode potential. Both methods indicate that stress-corrosion cracking decreases by lowering electrode potential and disappears below −380 mV (saturated calomel electrode). Current density-time plots made during constant straining and fractographic observations show different types of crack formation. The number of cracks increases with increasing potential, and the crack depth decreases with accelerated straining. Transgranular stress-corrosion cracking is observed accompanied by pitting. The selective corrosion in the early stage of cracking was revealed by scanning electron microscope (SEM) micrographs and SEM analysis. Iron and nickel are dissolved and a chromiumrich phase is formed along the crack walls. Although the first attack appears to be intercrystalline, the fracture shows only transgranular features.
Direct Measurement of the Corrosion Current for Oxygen-Reduction Corrosion
Authors: Postlethwaite J
Published: March 2009

The polarization-resistance technique has received considerable attention in the past decade as a means of determining the rate of corrosion. In aerated solutions of pH greater than 4, where oxygen reduction is the major cathodic reaction, there is a much simpler and more direct method of determining the corrosion current. The method involves the deaeration of the solution while the corroding specimen is held potentiostatically at its previously determined corrosion potential (Ecorr). The current supplied by the potentiostat when the solution is deaerated is the corrosion current (icorr). This method is suitable for laboratory and pilot-plant scale testing when the solution can be deaerated. The application of the method for the measurement of corrosion rates under controlled hydrodynamic conditions in pilot-plant pipelines carrying water and aqueous slurries is discussed along with the limitations of the method.
Effect of Large Voltage Modulations on Electrodes Under Charge-Transfer Control
Authors: Bertocci U , Mullen JL
Published: March 2009

The experimental test of the validity of a mathematical treatment of the effect of large a–c voltage modulations on the behavior of efectrodes under charge-transfer control was carried out for the case of the hydrogen evolution reaction. A frequency analysis of the resulting current showed that both d–c and a–c components of the faradaic current were in quantitative agreement with the predictions of the mathematical model. Deviations from the calculated values, which were observed in certain conditions (particularly at higher frequencies), were explained as the effect of the ohmic-drop error.
Appropriate Use of Titanium in Process and Process Equipment Design
Authors: Hulswitt CE
Published: March 2009

The versatility of titanium is all too frequently overlooked because process and mechanical designers fail to design processes and equipment with judicious use of material as a criterion.

Too often heat exchangers, first, are oversized and, second, use heavier-gage tubing and plate materials than required.

Detaclad material is used in vessels when solid titanium would be appropriate and less expensive. In turn, solid titanium is sometimes specified when conditions warrant a less-expensive loose linear construction.

Proper use of reinforcing rings is too often disregarded in vessel design. The extra material costs thus incurred can result in other less desirable materials being substituted for titanium.

Proper heat exchanger, reactor, and column design can be accomplished by using commonly available design criteria and common sense.

The heat-exchanger surface area can and should be optimally designed. Similarly, reactors and various mass transfer columns can and should be designed to minimize wall thickness or minimal use of titanium while providing the required contact time and suitable length/diameter ratios.

Perhaps the most important consideration is the appropriate use of titanium in energy conservation. Many titanium heaters and coolers can be replaced by all-titanium inter-changers with almost amazing payouts and long-term dollar and energy savings.
Tube Sheet Alternatives for Reactive Metal Tubed Heat Exchangers
Authors: Thomas JD
Published: March 2009

This paper looks at the variety of tube sheet constructions available for heat exchangers using titanium and zirconium tubing. Comparisons will be made of loose-lined versus solid or integrally clad tube sheets and of seal-welded versus rolled-only or strength-welded tube-to-tube-sheet joints. Alternatives will be evaluated with regard to their design reliability, economics, and maintainability.
Application of Surface Air Oxidizing to Prevent Hydrogen Embrittlement of Titanium in the Chemical Plant
Authors: Fukuzuka T , Shimogori K , Satoh H , Kamikubo F , Hirose H
Published: March 2009

Effects of surface treatment of titanium on hydrogen absorption were investigated. Surface-treated titanium specimens prepared by polishing, anodizing, and air oxidizing were immersed in 0.5 to 6 percent hydrochloric acid (HCl) solutions at a temperature range of 70 to 250°C. After immersion, the weight loss, hydrogen content, and oxide film thickness of three specimens were measured. As a result, it became clear that anodizing did not reduce hydrogen absorption of titanium because the titanium oxide film formed by anodizing had dissolved after a short period in dilute HCl solution; however, the air-oxidized specimen was stable in this solution for a long time, and therefore hydrogen absorption of titanium was prevented. These laboratory test results correspond to the results of field tests conducted in hot molten urea and mineral acid solution at high temperatures.
Titanium Use in the Pulp Industry
Authors: Seagle SR
Published: March 2009

The outstanding corrosion resistance of titanium in chloride environments is the basis for its increasing use in the pulp industry and the associated industries that generate bleach chemicals. As the pulp mills close their effluent systems because of government pollution regulations, the washing areas of bleach plants will experience an increase in chloride level and temperature. Preliminary test results show that the traditional construction materials, Type 316L and 317L stainless steels, will not be adequate, and an upgrading of materials in the washer filtrate systems and bleaching towers will be required. This is expected to result in increased usage of titanium in the pulp industry.
Corrosion Characteristics of Titanium and Stainless Steel in Solutions Containing Nitric Acid, Citric Acid, and Magnesium Chloride
Authors: Ciriscioli P , York JM , Dooley GJ
Published: March 2009

The corrosion characteristics of Type 304 corrosion-resistant steel (CRES), Type 316L CRES, and commercial purity titanium in chemical process solutions containing nitric acid, citric acid, and magnesium chloride were investigated at temperatures between 20 and 95°C for 24-h exposure periods. The testing was intended to simulate inplant corrosion problems and to provide information on which to base materials selection for replacement equipment. Analysis and results indicate that the Type 304 and 316L CRES materials had substantially less corrosion resistance to the corrosive solutions than commercial purity titanium.
No-Force Residential Burglaries: The Consequences of Negligence
Authors: Lentzner HR
Published: March 2009

According to a national survey of crime, unlawful entry without force (no-force burglary) is the most common type of residential burglary in the United States; each year incidents of this type account for hundreds of millions of dollars of cash and property loss. Unlawful entries without force are characterized by an absence of any visual signs of force, and, for a variety of reasons, are seldom reported to local authorities. This paper presents findings from the National Crime Survey, an ongoing survey of approximately 60 000 households across America. The analysis focuses upon such situational characteristics as time of occurrence, method of entry, and type and value of goods stolen. Results tend to confirm findings which show that many residential burglaries are crimes of opportunity committed by inexperienced offenders, some of whom might have been deterred if minimal security measures had been taken.
Crime and Economic Development
Authors: Burnette C
Published: March 2009

The lack of secure environments for business and industry presents a substantial obstacle to the economic revitalization of major American cities. Both existing and new investment is endangered and reduced by the unacceptable risks to personal safety and property found in older urban areas. Although essential to the protection of industrial capacity and goods, improved building security must be accompanied by: protection for the work force on the way to and from work; security for parked motor vehicles; security from arson and vandalism; and security of a psychological nature if workers with the needed skills are to be attracted to work within the older areas of the city that are most in need of economic development.

This form of security is highly dependent on the configuration of the overall environment, on sightlines, traffic layout, illumination, public services, entrapment patterns, work schedules, and public attitudes as well as on appropriate and reliable security programs, hardware, and systems. Of special importance is the design of urban industrial and commercial environments which promote positive patterns of human behavior and psychological security while frustrating criminal behavior. The potential for this approach has been indicated for multi-family residences by Newman, Cooper, Fowler, and others but has not been applied to the very grave problems of security for industrial and commercial activity in older urban areas.

The Special Session on Industrial and Commercial Security Through Environmental Design was organized to explore this approach, to discuss its implications for policy and program within concerned government agencies, and to identify avenues for research and demonstration projects which directly address the problem. To accomplish these goals the session was organized in a manner different from other sessions at this symposium. An illustrated presentation by the session chairman outlined the problem and the potentials of the approach. This was followed by commentary and discussion from an invited panel of distinguished Federal officials representing agencies having an interest in the issues of economic development, commerce, urban policy, and crime prevention. This paper conceptualizes the approach, presents the outcome of the panel discussions, and outlines appropriate research initiatives. Research program outlines and an executive summary have been also prepared.
School Building Security—A Need for Standards and Guidelines
Authors: Schnabolk C
Published: March 2009

This paper is a general survey and analysis of the growing problems relating to school security. It discusses the neglect and indifference of various educational, governmental and professional organizations in their dealings with the menace confronting our 100 000 schools in the nation. It details the increase in crime taking place within the school corridors and recommends certain actions that may help regain control of the school from the vandal and juvenile criminal. The theme of the paper is a general criticism of the actions of the educational community that refuse to believe that our schools are being attacked by students and that the problems are spreading from the urban centers to the suburbs. A great deal of emphasis is placed on the lack of standards and guidelines relating to security hardware.
Background Correction Used with a High-Resolution Spectrometer for Plasma Emission Spectrochemical Analysis
Authors: Zander AT
Published: March 2009

An echelle grating spectrometer can be configured in a straightforward fashion to provide short-range scanning. With this capability, the instrument enables observation of the wavelength regions a few spectral bandwidths on either side of an analyte line for the investigation of suspected spectral interferences. Acquisition of scan data of this sort can simplify the decision of whether or not to use some type of background correction procedure. Various background correction approaches are available with this short-range wavelength scan capability.

The characteristics of a high-resolution echelle grating polychromator which has dynamic background correction capabilities is described. Its use for the elimination or alleviation of a number of suspected and verified cases of spectral interferences is examined.
Multielement d-c Plasma Emission Spectrometric Analysis of Steels and Irons
Authors: Belliveau J , Griffin H , Savolainen A
Published: March 2009

Simultaneous multielement trace analysis of steel alloys by d-c plasma emission echelle grating spectroscopy (DCP) has been developed using a single-matrix synthetic standard. Emission lines free from spectral interference have been selected by scanning wavelength regions, and their analytical capabilities have been characterized. Background shifts and enhancement effects were overcome by using an iron matrix synthetic standard. Sixteen elements at concentrations of less than 1 weight percent were simultaneously analyzed in up to 60 certified steel alloy samples. The DCP results compared favorably with the certified values and were accurate to within 10 percent for most elements. The precision of the analyses, indicated by the standard deviation of at least four repeat runs, was less than 10 percent.
Isotope Dilution Spark Source Mass Spectrometric Determination of Sulfur in Selected NBS Iron-Base Alloys
Authors: Paulsen PJ , Burke RW , Maienthal EJ , Lambert GM
Published: March 2009

A procedure has been developed at the National Bureau of Standards utilizing isotope dilution spark source mass spectrometry (ID-SSMS) for the determination of sulfur in iron-base alloys. With this technique a known amount of highly enriched sulfur-34 (34S) isotope (spike) is added to the sample, and, after physical and chemical equilibration between the spike sulfur and the natural sulfur in the sample, the equilibrated sulfur is isolated by reduction to hydrogen sulfide (H2S) and precipitation as silver sulfide (Ag2S). The altered isotopic ratio of the sulfur (32S/34S) is then measured with the spark source mass spectrometer. The sulfur concentrations are calculated from the sample weight, spike weight, measured altered isotope ratio, and known isotopic abundance of 34S and 32S in both the natural and spike sulfur. The key step in obtaining a quantitative sulfur analysis is the dissolution of the sulfur-containing iron samples in a sealed tube. This dissolution procedure enables the sample sulfur and the spike sulfur to equilibrate completely without any possibility of loss of either species by volatilization.
Some Field Studies of the Correlation Between Electromagnetic and Direct Current Measurements of Ground Resistivity
Authors: Arcone SA
Published: March 2009

Electromagnetic (em) and direct-current (d-c) methods of measuring ground resistivity have been compared at permafrost and nonpermafrost sites. The em methods utilized the principles of magnetic induction and plane wave surface impedance. Layered ground models were derived from the d-c sounding data, and the theoretical values of the em methods for these models were compared with the em field results. Both em methods correlated well with the d-c data in the two cases of simple, multilayered ground of large extent. In several cases of resistive inhomogeneities, the magnetic induction data correlated well with the d-c data. In one case of a resistive inhomogeneity, the surface impedance responded well only qualitatively and may have given some false indications of resistive substructure. It appears that in all cases where the volume of exploration was comparable, there was reasonable correlation. It is estimated that the standard data analysis procedure which assumes layering of infinite extent will apply well for the surface impedance method when disturbances in the local layering are greater than a skin depth away from the point of measurement; and for the magnetic induction method when disturbances in the layering are at a distance from the interloop axis that is greater than the interloop separation.
Monitoring Power Plant Water Chemistry
Authors: Pocock FJ
Published: March 2009

The objectives and requirements for water quality monitoring in utility power plants is discussed in an overview fashion. This includes the available instrumentation and some discussion of further development work that is needed.
Status of Continuous Monitoring in Central Stations
Authors: Noll DE
Published: March 2009

The high level of sophistication required for the continuous monitoring of water quality in central stations follows from the need to produce ultrapure steam. Although there may not be agreement on the precise levels of contamination that are tolerable in steam, there is concensus that the levels are extremely low—so low, in fact, that it is questionable whether commercially available instrumentation has been adequate for the job.

During the past 5 years or so, the disastrous consequences of caustic and sodium chloride in steam have been emphasized over and over, yet many central stations do not take advantage of the instrumentation that is available for monitoring these contaminants.

Once the steam requirements are established, the specifications for boiler water and feedwater follow in order. This paper outlines several monitoring schemes for the complete utility plant cycle which employ the best monitoring equipment currently available and discusses some of the reasons that improved instrumentation is required.

The author points out that there are frequently alternative methods for detecting contamination in condensate and describes how the most sensitive monitoring device is selected in each case.
Power Plant Water Quality Instrumentation: A Guideline for Operation, Calibration, and Maintenance
Authors: Selby KA
Published: March 2009

The paper focuses on how the organizational structure within a power plant can help or hinder in the effort to obtain reliable data from water quality instrumentation. It also focuses on the education and training level required of personnel who operate such instrumentation and provides guidelines for daily attention to instrumentation and recommendations for the scheduling of routine maintenance and calibration procedures.
Quantification of Sodium, Chloride, and Sulfate Transport in Power-Generating Systems
Authors: Willhite TB , Sawochka SG , Pearl WL
Published: March 2009

In the performance of several chemistry monitoring programs for pressurized water reactors sponsored by the Electric Power Research Institute (EPRI), integrating sampling devices are employed to concentrate low-level impurities present in the power-generation cycle. The devices employ a conventional Millipore membrane for collection of filterable species and separate cation and anion ion-exchange columns for ionic species. The preparation for the ion-exchange columns involves resin pretreatment aimed at complete regeneration of resins, and in situ regeneration to ensure resin cleanliness and uniformity following column assembly.

To complement and expand on results from the integrating ion-exchange columns, ion chromatography and specific ion electrode techniques were employed during short-term studies. These alternative techniques allow transient conditions to be monitored, whereas the integrated sampling system is deficient in this respect. Sodium, chloride, and sulfate concentrations determined with the different techniques were compared, and agreement was considered adequate for achieving program goals.
Evaluation of Power Plant Measurement of Sodium Ions in High-Purity Main Steam and Feedwater Utilizing In-Line Continuous Specific-Ion Electrodes
Authors: Eherts RF
Published: March 2009

This paper discusses the measurement of trace-level sodium concentrations in aqueous solutions. A comparison between the specific-ion electrode analyzer and other analytical methodologies is presented. The techniques include atomic absorption spectroscopy, flame emission spectroscopy, and ion chromatography. The data were obtained over approximately a 300-day period utilizing combinations of the aforementioned analytical techniques. The evaluation was performed at Calvert Cliffs Nuclear Power Plant (CCNPP), Lusby, Md., a pressurized water reactor owned and operated by Baltimore Gas and Electric Co. (BG & E). The data revealed that significant perturbations in the indicated sodium concentrations on the specific-ion electrode analyzers existed during the study period. Based upon the comparison data obtained by other analytical methodologies, the indicated sodium level variances were not considered to be representative of the actual system concentration variances. The perturbations in the indicated sodium levels were correlated with flow-pressure fluctuations in the specific-ion electrode sample lines. In addition, the accuracy of the instrument was diminished as the actual system sodium concentration varied outside the calibration limits of the analyzer.
Continuous Conductivity Monitoring of Anions in High-Purity Water
Authors: Lane RW , Sollo FW , Neff CH
Published: March 2009

This paper describes the continuous and accurate monitoring of electrical conductivity of anions in feedwater and turbine condensate by two new instruments, a Feedwater Analyzer and a Condensate Reboiler. As has been pointed out, the advantages of this testing technique are that carbon dioxide and ammonia interferences are eliminated, the conductivity is measured at constant temperature, and increased sensitivity to anions is attained by measuring the conductivity of anions in the acidic and more conductive form. Design changes in this equipment have made possible more accurate conductivity measurement in the range of 0.01 to 0.1 S/cm at atmospheric boiling water temperature. This results in increased sensitivity of measurement, so that 1 to 5 ppb of Cl− + SO=4 can be determined.

An advantage is shown in that low levels of 0.01 to 0.05 mg/litre of carbon dioxide (CO2) have a lower conductivity at atmospheric boiling temperature than at room temperature (25°C). More accurate cation conductivity results may therefore be expected by measurement at atmospheric boiling water temperature than by degassing with nitrogen.

By including pH measurements along with conductivity and temperature measurements at room temperature, it is shown that ammonia and carbon dioxide of this two-component system may be calculated. Calculated ammonia and carbon dioxide results are shown not to be appreciably affected by the presence of 10 ppb chloride or more. The presence of 100 ppb total organic carbon (TOC) (as acetic acid) in steam condensate is also shown to have a negligible effect on the calculated ammonia and carbon dioxide results above 3 to 4 μS/cm.
Determination of Trace Chlorine and Oxidants in Seawater by Differential Pulse Polarography
Authors: Washinger G , Kark P
Published: March 2009

This paper describes a rapid and reliable technique for the determination of chlorine and other oxidants in power plant and industrial cooling waters, with particular emphasis on seawater systems. The analytical work is based upon the standard technique of chlorine and oxidant reduction by phenylarsine oxide. Excess phenylarsine oxide is detected quantitatively and nondestructively by differential pulse polarography and has a detection limit of less than 5 ppb chlorine equivalent.

The procedures described in this paper are shown to be applicable for the analysis of total residual chlorine. However, extension of the principle to other types of oxidant determination under different conditions of pH and catalyst should be straightfoward.
Application of Single Edge Notched Beam and Indentation Techniques to Determine Fracture Toughness of Alpha Silicon Carbide
Authors: Srinivasan M , Seshadri SG
Published: March 2009

This paper is concerned with procedural developments for the application of single edge notched beam (SENB) and indentation techniques to determine the fracture toughness of sintered alpha silicon carbide. For the SENB method, the following experimental variables were examined: relative notch depth, deformation speed, temperature, and atmosphere. Based on the results, a notch depth ratio of 0.4 and a deformation speed of 8.46 × 10−6 m/s (0.02 in./min) are recommended for this material. The effect of temperature in air on KIc determination is such that crack blunting occurs due to oxidation, yielding erroneous results. By using Vicker's indentation with varying loads, fracture toughness values were calculated from careful measurements of dimensions of median cracks and the indentations. In addition, Knoop indentations with loads ranging from 1 to 5 kg were made. The results of this controlled surface flaw technique showed that the fracture toughness was independent of the indentation load used. Residual stresses caused by indentation were removed by surface grinding as well as by annealing in argon at 1000 to 1200°C. These procedures increased KIc-values by approximately 20 to 40 percent. The greatest experimental difficulty in the controlled flaw method for alpha silicon carbide arises in the flaw profile estimation from SEM fractographs. In the majority of cases, there are no clear mirror-like surface flaws beneath the indent causing errors in measurement of flaw sizes.
Effect of Stable Crack Growth on Fracture Toughness Determination for Hot-Pressed Silicon Nitride at Elevated Temperatures
Authors: Munz D , Himsolt G , Eschweiler J
Published: March 2009

Fracture toughness of hot-pressed silicon nitride was determined between room temperature and 1300°C using four-point bend specimens with straight-through and chevron notches. For T > 1100°C fracture toughness increases due to crack branching and secondary cracking caused by the viscous flow of the grain boundary phase. To determine correct K-values with the specimens having a straight-through notch the stable crack extension at T > 1100°C has to be taken into account.
Test-Microstructural Dependence of Fracture Energy Measurements in Ceramics
Authors: Rice RW
Published: March 2009

This paper first reviews the microstructural dependence of fracture energy (γ) for the typical fracture mechanics techniques used for ceramics. Next both agreement and substantial disagreement between the different techniques, for example, as a function of grain size, porosity, and second phase contents, are discussed in terms of microstructural-test interactions, such as effects of microcracking. Then strength and other related mechanical behavior are compared with predictions from γ measurements, showing important disagreements which are related to the same factors effecting γ tests, that is, microstructural-crack size factors.
Specimen Size Effects in Fracture Toughness Testing of Heterogeneous Ceramics by the Notch Beam Method
Authors: McKinney KR , Rice RW
Published: March 2009

The variation of apparent KIc with crack length is being studied using a variety of commercial ceramic materials. Test methodology is much the same as has been used in the past for natural rock (notched bend test). Where sufficiently definitive data have been obtained, each material showed decreasing KIc with decreasing crack length with all values falling below KIc determined using constant K specimens (double torsion or constant-moment-arm tests).

Included in the study was soda-lime glass because it was anticipated that no size effect would occur. Large variations (a factor of two) did occur, however, differing in that all values were above constant K specimen KIc. Post-mortem fracture surface examination revealed problems that can occur where a specimen-wide sharp crack is not achieved before testing.
Precursors of Laboratory Rock Failure
Authors: Rowell GA , Brady BT , Yoder LP , Hanson DR
Published: March 2009

A series of laboratory tests was initiated at the Bureau of Mines to investigate the relevance of brittle rock failure in the laboratory to large-scale failures, such as rock bursts and roof falls in mines. Various parameters that could exhibit anomalous behavior prior to failure were monitored during uniaxial and triaxial compression tests. These parameters included load, moments (corresponding to tilt measurements), seismicity, electromagnetic (EM) radiation, surface charge differential, and confining pressure (during triaxial tests). These variables were recorded for only a few milli-seconds prior to and during failure.

Our results indicate that laboratory failure of brittle rocks, such as granites and quartzites, must be studied in the microsecond time scale prior to failure; otherwise, laboratory failure appears to be a single catastrophic failure with little or no relevance to large-scale failures. Studied on the microsecond time scale, anomalous activity was observed in the last 10 ms prior to failure. During triaxial compression tests, a large pressure drop was observed just prior to failure, indicating that a criterion for failure may be the violation of the law of mechanical stability.
Consequences of Varying Surface Heat Transfer Coefficients, Material Properties, and Cyclical Ambient Temperatures upon Stress Intensity Factors for Edge Cracks
Authors: Emery AF , Kobayashi AS , Bieler TR
Published: March 2009

Stress intensity factors were calculated for an edge crack subjected to time varying surface heat transfer coefficients and to cyclical ambient temperatures. Both constant and varying material properties were used and values of KI are presented as functions of crack depth and time. Substantial changes in the maximum values of KI were noted for these different cases. In general, quench tests with specimens whose material properties increase with temperature show much lower values of KI than do specimens with material properties which are either constant or decrease with temperature.