bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neoprene in Bridge Bearing Pads—The Proven Performance
Authors: Burpulis JS , Seay JR , Graff RS 
Published: March 2009

Elastomeric bearings have a long and successful record of performance supporting bridges, railroads, buildings, and heavy machinery. Bearings based on neoprene synthetic rubber have been in use in the United States since 1957. Today, millions of bearings based on neoprene support highway and railroad bridges throughout the world.
Elastomeric bearings are economical, effective, and require no maintenance. They are simple solid pads with no moving parts. The pad deflects in shear to accommodate expansion, contraction, and end rotation of the bridge structure. There is no need for lubrication, no need for cleaning, and no opportunity for the bearings to seize.
Sound bearing design principles have been developed based on experience accumulated over the years. This paper will highlight installations using neoprene bridge pads with 17 to 32 years service to describe the technology necessary to document their performance. Physical property data on these aged neoprene pads will be presented.
Designing Bridge Decks to Match Bridge Life Expectancy
Authors: Bettigole NH 
Published: March 2009

The easiest purchasing policy to enforce is least first cost. Under TQM (total quality management), the new mandate is to obtain least life cycle cost.
Experience with highway bridge construction in the United States is that the usable life of the bridge deck is only one half of the useful life of the bridge. The average age of bridges when replaced is 68 years, and the average length of service of bridge decks before replacement is 35 years.
Bridge deck replacement during the service life of the bridge is much more costly than a new deck on a new bridge, due primarily to the requirements of traffic maintenance during the construction phase of bridge rehabilitation projects.
Estimation of the cost of construction of design options for life cycle and serviceability, although extremely difficult to document objectively, must now be accomplished. New public policy has enunciated the importance of determining relative life cycle costs.
Estimated bridge costs in the 1950s were $20 to $40 per square foot. Estimates of bridge rehabilitation cost in the 1990s will be $70 to $200 per square foot.
This paper reviews various bridge deck construction methods and the theoretical and historical comparisons which may be observed. A discussion of how design, construction, and service considerations impact life cycle cost and serviceability is included for several types of bridge deck.
In his conclusions and recommendations, the author proposes guidelines for comparing available bridge deck types. The discussion includes checklists of specific project needs, whether new or rehabilitation designs, to meet the objective of matching bridge and deck useful life.
Fourteen Years' Service with Deep Impregnation of a Reinforced Concrete Bridge Deck
Authors: Weyers RE , Cady PD , Feeney MA , How Lum SF 
Published: March 2009

A test installation of deep impregnation was applied to a heavily traveled bridge deck in Bethlehem, Pennsylvania, in 1975. The deep impregnation process involves drying the concrete, impregnating with a monomer to a depth of 3 to 4 in., and polymerizing the monomer in situ. At the time of the impregnation, the bridge deck was eight years old and the chloride contents were above the corrosion threshold level. The test area, 3.7 m2, is centered on the right wheel path of the traffic lane.
During the 14-year period, spalling and delaminations have occurred, on 20% of the deck with no evidence of spalling or delamination in the impregnated area. The deep impregnation has reduced the surface wear in the wheel path by 65%. Chloride contents have increased in both areas but at a slower rate in the impregnated area. The percent active corrosion potentials have remained the same in the nonimpregnated area but increased to 50% in the impregnated area. However, the corrosion current in the impregnated area is a factor of six less than in the nonimpregnated area. The concrete resistivity is a factor of six higher in the impregnated area and of sufficient magnitude to significantly reduce the rate of corrosion. Microscopical examination of cores showed that preexisting corrosion cells were arrested by the impregnation process.
A Review of Modern Instrumental Methods of Elemental Analysis of Petroleum Related Material: Part I—Occurrence and Significance of Trace Metals in Petroleum and Lubricants
Authors: Nadkarni RA 
Published: March 2009

Almost all elements in the periodic table are found in petroleum products, varying from percent levels for C-H-S to parts per million and parts per billion levels for transition metals. The presence of elements in crude oil is ascribed to its marine animal and vegetative origin. Compared with two other fossil fuels — coal and oil shale — petroleum is a lesser source of environmental pollution. Extensive data on crude oils composition are available. Determination of S, N, V, Ni, and Fe form an integral part of crude assay analysis of oils carried out by all oil companies. Generally it is agreed that V, Ni, and Fe occur as metallo-porphyrins; Hg, Sb, and As as organometallic compounds; Mo and Ge as carboxylic acid salts; and silica and NaCl as colloidal minerals.
The significance of metals either naturally present in crude and gasoline or purposely added to petroleum products is described. Trace metals in used lubricating oils indicate the wear performance of an engine, and can be used as a preventive maintenance check. A number of sample preparation schemes are necessary depending on the analytical technique to be used. This can vary from procedures as simple as dilution for XRF or AAS, to more involved procedures such as oxygen bomb combustion for ion chromatography, or wet ashing for AAS or ICPAES. Frequently, robots are used to speed sample dilution for XRF or ICPAES.
For quality assurance of these analyses, standard reference materials (SRMs) are used. At least three sources of these materials are Alpha Resources, Leco Corporation, and the National Institute of Standards and Technology. SRMs for crude oil, diesel oil, fuel oil, kerosene, lube oil, paraffin oil, and petroleum coke are currently available.
Techniques to Improve the Ability of Spectroscopy to Detect Large Wear Particles in Lubricating Oils
Authors: Lukas M , Anderson DP 
Published: March 2009

Machine condition monitoring through oil analysis is a proven and cost-effective maintenance management technique. Periodically, however, the ability and need of the analytical techniques to detect large wear particles are questioned. Today there is general consensus as to the maximum wear particle size capability of atomic emission spectrometers (AES) and atomic absorption spectrometers (AAS), but few agree on the ways to improve them. This paper discusses three techniques that can be used to improve the ability of optical emission spectrometers to detect and quantify large wear particles in lubricating oil.
The single spark technique is based on an atomic emission spectrometer readout system that stores the intensity of individual excitation sparks for each element and presents the data as a particle size distribution. The system can operate in real time and provide information on each analysis, or the output can be suppressed and the user alerted only if wear particles exceed a preset size limit. Test data has shown an ability to detect and identify wear particles up to 40 μm in size.
The ashing rotrode technique is based on a sample introduction and analysis system in which the oil sample is deposited on a graphite electrode, then resistively heated to desolvate the oil matrix. The desolvated matrix is subsequently excited by a pulsed D-C arc, and the spectra is analyzed by a polychromator. This technique minimizes matrix effects, enhances spectral sensitivity, and greatly improves detection of large wear particles.
The acid digestion differential technique is based on two analyses of the same oil sample. The sample is analyzed with and without acid to dissolve wear particles. The difference in the two readings indicates the presence of large wear particles.
All three techniques discussed in this paper improve the ability of spectrometric techniques to detect, quantify, and identify wear particles. Capabilities and limitations of each are discussed. The technique of choice varies with the requirements and philosophy of the analytical laboratory.
Precious Metal Assay Analysis of Fresh Reforming Catalyst by X-Ray Fluorescence Spectrometry
Authors: McElroy FC , Mulhall JM 
Published: March 2009

Precious metal analysis of fresh reforming catalysts are typically performed by both the catalyst manufacturer and buyer to arrive at a financial settlement on the quantity of metal in each lot of commercial catalyst: Traditional assay methods involve a variety of fire assay or wet chemical acid digestion schemes coupled with gravimetric, colorimetic, or titrimetric measurement for precious metals. Methods must have sufficient precision and accuracy to afford interlaboratory agreement of within one half of one percent relative between the catalyst supplier and purchaser. To meet this requirement many laboratories rely on classical methods. Unfortunately these procedures are labor intensive and time consuming.
X-ray fluorescence has the inherent instrument precision to achieve typical intralaboratory precision of 0.5% RSD on a wide variety of elements and numerous sample types. We have developed an X-ray fluorescence method for the assay quality analysis of fresh reforming catalysts containing platinum, rhenium, and iridium. This method was applied to numerous samples over the past five years.
The XRF method uses chemically assayed fresh catalysts as comparison standards to quantify the X-ray fluorescence response on unknown samples. Samples and standards of the same matrix and nominal elemental concentrations are ground, dried overnight, and then allowed to air equilibrate. Standards and samples are pressed into briquettes with alumina cups in a pellet press to 20 tons. Net counts for each element are collected at the appropriate wavelengths for both standards and samples. Analysis is performed on a minimum of three sample briquettes and four briquettes for each of three standards. The ratio of the net counts to the precious metal concentration on each standard is averaged to obtain a calibration factor. Platinum alone and platinum in combination with other promoter precious metal concentrations are calculated by taking the average sample net counts for each element and dividing by the appropriate calibration factor. Intralaboratory and interlaboratory results are presented showing the applicability of X-ray fluorescence as an assay quality procedure for precious metal analysis.
Energy Dispersive X-Ray Fluorescence Spectrometric Determination of Vanadium, Nickel, and Iron in Petroleum and Petroleum Residua
Authors: Shay JY , Woodward PW 
Published: March 2009

Trace metals such as vanadium, nickel, and iron in fluid catalytic cracking feedstocks deposit on the catalyst and adversely affect catalyst activity and product yields. Vanadium compounds can also cause damage to furnace linings and corrosion of boiler tubes or gas turbine blades. A rapid and sensitive analytical method is needed to detect these metals in feedstocks, products, and residua. Such a method using energy dispersive X-ray fluorescence (EDXRF) spectrometry for determination of vanadium, nickel, and iron in petroleum and petroleum residua is described.
In order to eliminate matrix effects, samples containing an internal standard (cobalt) were decomposed by heating with concentrated sulfuric acid and the resulting carbonaceous residua were ashed. X-ray fluorescent spectral intensities of V, Ni, Fe, and Co were measured using established instrumental parameters. Since the Fe Kβ and Co Kα lines overlapped, the slope and the intercept of the ratio of Fe Kα to Fe Kβ intensities from the analysis of ash of several iron standards were used for correction of Co spectral intensities. Sample metal concentrations were determined by comparison of spectral ratios to those of ashed calibration standards. Analytical data obtained by this procedure for National Institute of Standards and Technology (NIST, formerly NBS) Standard Reference Materials (SRMs) 1618, 1634b, and 8505 were in very good agreement with the NIST certified values. The metal contents of petroleum and petroleum residua determined by this EDXRF method also agreed with those obtained by a flame atomic absorption method. This analytical approach could be developed into an ASTM standard method and the scope extended to include determination of other metals.
Improved Performance for Trace Halide Determination in Hydrocarbons
Authors: Ohlson GG , Takahashi Y 
Published: March 2009

Microcoulometry has been widely used to measure halides in hydrocarbons. While microcoulometric analysis is well-established, some types of hydrocarbons (i.e., crude oils, heavy fuel oils, hydraulic fluids, and others) require special attention due to their physical and chemical properties. In the past, slow combustion with higher temperatures (1000°C or greater) was recommended; however, sluggish response due to refractory components, the presence of heavy metals, or the rapid aging of the quartz combustion tube under such conditions has made data interpretation difficult at times.
Analysis of heavy hydrocarbons was improved by changing the combustion tube design and adding cupric oxide wire to the combustion outlet zone. With this scheme, it is not necessary to use high furnace outlet temperatures. Combustion efficiency and system response improve, while the effects of deposits and corrosion are greatly reduced. Crude and #6 fuel oils, phosphate ester fluid, and base lube oil additives were tested under these conditions, yielding better recovery and improved precision for some by a factor of three or greater.
A post-combustion scrubber developed for solvent analysis was evaluated for refractory hydrocarbon analysis. It had little effect on the detection limit, but could be used to remove deposits.
Examination of Selected NDE Techniques for Ceramic Composite Components
Authors: Dunyak TJ , Stinchcomb WW , Reifsnider KL 
Published: March 2009

Nondestructive techniques are needed to detect defects, monitor the various states of material, and characterize damage development in ceramic matrix composite (CMC) specimens and components. Although some nondestructive examination (NDE) methods yield more information than others, generally no one method will provide all the required information. Therefore, a combination of NDE methods is necessary to fully investigate specimens and components before, during, and after testing.
This paper examines a variety of NDE methods to meet these needs. The investigation covers a wide variety of methods from typical optical microscopy to highly developmental techniques such as acoustoultrasonics and scanning acoustic microscopy. The paper provides an information base on the application of NDE techniques to ceramic composites to assist researchers in planning and selecting NDE methods for CMCs.
The paper is divided into three main sections. The first section briefly describes the fabrication of the specimen and the mechanical test series. The second section contains a discussion of the application of selected NDE methods and a short synopsis of each of the methods examined. The third section summarizes the NDE results in conjunction with the mechanical test results. In this section, a correlation of the initial defects, observed damage development, and failure surface analysis is provided to identify the critical performance limiting defects in chopped fiber-reinforced borosilicate glass tubes.
Design Parameters of a Serpentine Optical Fiber Bending Transducer for Strain Measurements in Smart Structures
Authors: Demirdogen AC , Houghton JR , Tay AK , Wilson DA , Wood RL 
Published: March 2009

A unique optical fiber transducer for measurement of bending strains that can be used for display of distributed strains in a structure is described. A mathematical model for the design of this transducer with circular segments is presented. The attenuation along one 360° segment with respect to bending radius and a biaxial stress field is derived. Analytical results show that the serpentine transducer is most sensitive to curvature of the plane that includes the circular segment. The effects of the bending curvature on a circular segment, when the center of curvature is in the same plane as that of the circular segment, is for the attenuation to average out to produce relatively small net change as a function of curvature.Experimental results are presented to show the output of net attenuation through the serpentine transducer. Three-point bending tests demonstrate the problem of selection of the initial circular segment radius to avoid the whispering gallery mode of attenuation fluctuation.
Defect Classifications in Composites Using Ultrasonic Nondestructive Evaluation Techniques
Authors: Steiner KV 
Published: March 2009

The growing use of advanced composites in structural applications has intensified the need for nondestructive technologies to locate, identify, and classify defects and flaws in composite structures with increasingly complex geometries. Ultrasonic nondestructive testing methods have proven to be successful and reliable in the inspection and certification of composite structures that are scanned by sophisticated, automated, multiaxis robotic systems. Digitizing of the ultrasonic information has introduced powerful computer graphics image enhancement techniques to aid in the interpretation of the results.
Research results of comparative studies are presented that take advantage of advanced robotic scanning and subsequent image enhancement technologies. A variety of ultrasonically detectable defects such as porosity, contaminations, delaminations, fiberor matrix-rich areas, fiber orientation, and impact damage are interrogated. Flaw growth models for fatigue samples are discussed, addressing the flaw criticality issue, a growing area of interest in the characterization of composite structures.
Modelling of Impact Damage Features in Graphite/Epoxy Laminates
Authors: Chester RJ , Clark G 
Published: March 2009

This paper describes recent work in which improved nondestructive evaluation (NDE) techniques for impact damage in graphite/epoxy composites have been used in conjunction with two different approaches to damage modelling to improve prediction of structural response under compressive loading.
Impact-induced delaminations occurring at different interfaces within the laminate exhibit different orientations and sizes. A model has been developed to explain this behavior, in which the forces acting on two adjacent nonparallel plies during impact are considered. Regions in which the model predicts positive peel forces have been shown to correlate closely with actual delaminations in a variety of impact-damaged laminates. The model also considers the role of intraply cracking, which provides boundaries to the impact delaminations and plays a part in forming characteristic delamination/cracking features in the damaged laminate.
Following detailed characterization of the impact-damaged zone using ultrasonic C-scanning and sectioning, experimental models have been produced in which polytetrafluoroethylene (PTFE) inclusions simulate the shape and extent of all the delaminations present in the impactdamaged zone. Compression tests on these specimens lead to failure strengths that are comparable to those of impact-damaged specimens and which are considerably lower than those of specimens containing single PTFE inclusions. These results suggest that the delaminations are more significant than ply cracks or fiber failures in determining the compressive behavior of impact-damaged laminates.
The predictive capability resulting from the modelling aspects of this work and the improvements in inspection methods provide considerable potential for accurate assessment of impactdamaged components for subsequent repair.
Introduction to Food Packaging
Authors: Cage JK 
Published: March 2009

The basic principles of packaging to preserve, merchandise, protect, market, and distribute are applied very effectively in the food industry. More recently, food packages have been developed which offer tamper-evident or tamper-resistant features, allow for product preparation, and provide dispensing features and many conveniences such as single serving portions. Often the food product and its package are developed to be an integrated unit such as an aerosol product.
Technological breakthroughs in metals, glass, paperboard, composites, and most especially plastics have provided a multitude of opportunities for improved food packaging. The plastics segment of the packaging industry has shown the most rapid growth for many reasons. Some of the most important are: some plastics can be used in microwave ovens; plastics have a wide range of physical and barrier properties; and plastics offer design capabilities and features not available with other packaging materials.
However, ecological and environmental concerns are growing rapidly, along with federal, state, and local regulations and laws which will have an effect on the whole packaging industry. Further, the demographic changes related to the increased percentage of older consumers will also have significant effects on food packaging in the future.
The Determination of Moisture Stability of a Dynamic System Under Different Environmental Conditions
Authors: Marsh KS , Ambrosio T , Guazzo DM 
Published: March 2009

Effervescent tablets defy standard analysis for moisture sensitivity. High humidity conditions cause effervescence with corresponding changes in the tablet composition. However, the time necessary to perform traditional shelf life testing on a product which requires a two-year shelf life was considered too lengthy. An accelerated testing protocol was therefore desirable.
Novel analytical techniques were developed to determine the product's response to humidity changes. Computer modeling was then employed to define product response to two isothermal storage conditions and three dynamic distribution environments in a nonfoil blister package. The results predicted that the two-year shelf life would be achieved.
The product's two-year shelf life was established in three months of research time. The product, Fibre Trim effervescent tablets, became the first effervescent tablet to be introduced in a nonfoil package worldwide.
The computer estimates have since been confirmed with storage studies.
High Barrier Plastics Packaging and Ethylene Vinyl Alcohol Resins (a Marriage)
Authors: Schaper EB 
Published: March 2009

In 1983, with the introduction of the first multilayer high barrier plastic bottle in the United States, a revolution was started in the food packaging industry. This revolution has gained momentum over the last five years so that today almost any type of food product is a candidate for packaging in a high barrier plastic container. Food products are not the only candidates, however; many nonfood products such as chemicals, health care products, electronic parts, etc. are taking advantage of the excellent cost/performance properties of high barrier plastics packaging. One of the primary reasons for the acceptance and functionality of this type of packaging is ethylene vinyl alcohol copolymer (EVOH) resins.
This paper will review multilayer plastics packaging applications, their markets and economics from 1983 to the present, and why EVOH resins play a very important role in the “packaging revolution.”