bluuebunny/crossref_metadata_2025 huggingface dataset:
ASTM Specifications and Test Methods for Polymer-Modified Mortar and Concrete — A Status Report
Authors: Kuhlmann LA
Published: March 2009

Mortar and concrete test methods currently being used with polymer modifiers (latexes and redispersible powders used with hydraulic cements) are generally standard ASTM procedures with minor variations to accommodate the properties unique to these materials. These variations typically relate to such items as proportioning, mixing sequence, and curing. Subcommittee C09.03.19 is currently preparing documents that will address the changes needed in the appropriate existing Standards and Practices. Also under development by the Subcommittee is a new direct tension test method for measuring adhesion of concrete and mortar to concrete, and a specification for polymer modifiers that defines the products and provides criteria for the properties of mortar and concrete made with them.
The Effect of Polymer Variables and Other Parameters on the Properties of Polymer-Modified Cement Mixtures
Authors: Walters DG
Published: March 2009

Polymer-modified hydraulic cement mixtures (PMC) are widely used for a variety of applications. The literature to-date on PMC is considerable but little has been published examining the effect of variables within the polymer on the properties of PMC. The work described in this paper attempts to partially fill this void. The studied variables include polymercement ratio, latex particle size, glass transition temperatures, effect of carboxylation and pH value. Also the effect of wet and dry curing of PMC is examined. The theory of polymer-modification of hydraulic cement mixtures is discussed in light of these results.
Effect of Coating with Flexible Polymer Modified Cement Mortar on Inhibition of Alkali Silica Reaction
Authors: Kamimoto H , Wakasugi M
Published: March 2009

Coating material for repair of concrete structures damaged or deteriorated due to alkali silica reaction (ASR), requires water vapor permeability as well as water impermeability. It requires, furthermore, strong adhesion to concrete and elongation for the remaining expansive power of ASR. A flexible polymer modified cement mortar (PCM), which consists of flexible polyacrylic polymer dispersion, portland cement and admixtures has above-mentioned performance.

Physical properties of the flexible PCM were measured at various polymer cement ratios. Water and water vapor permeability of the flexible PCM was reduced with increasing in polymer cement ratio. Since the flexible PCM with a high polymer cement ratio had a structure in which the larger pores were filled by polymer and sealed by continuous polymer film, elongation of the flexible cement mortar tended to increase with increasing in polymer cement ratio. Whereas adhesion had an optimum polymer cement ratio.

A field exposure test was performed using concrete specimens damaged by ASR. The specimens were coated with either epoxy resin or the flexible PCM at various polymer cement ratios. Coating with the flexible PCM was found to inhibit ASR, but the epoxy resin promoted ASR. The ASR expansion was reduced with increasing in water vapor permeability of the flexible PCM.
Skier Injury Trends—1972–1990
Authors: Johnson RJ , Ettinger CF , Shealy JE
Published: March 2009

Between 1972 and 1990 the authors evaluated prospectively 6671 injuries reported to the injury clinic operated in the base lodge of a moderate size northern Vermont ski area. During that time approximately 2 032 000 skier-visits occurred at the area. The overall injury rate decreased by 48% during the study. Lower leg injuries improved the most with an 83% reduction noted. Overall, the incidence of knee ligament injuries didn't change significantly. However, the incidence of minor to moderate injuries did diminish by 70% while severe knee sprains, usually involving the anterior cruciate ligament, increased very significantly (209%). In general, the incidence of upper body injuries did not change although upper body lacerations and thumb ulnar collateral ligament sprains improved by 55% and 59% respectively, while clavicular fractures increased in incidence significantly (176%).
Comparison of Downhill Ski Injury Patterns—1978–81 vs. 1988–90
Authors: Shealy JE
Published: March 2009

This study repeats and expands upon an earlier study done by the principal investigator ten years ago. The study looks at trends in downhill (DH) skiing over the last ten years; differences between control and injured groups of skiers; differences between male and female skiers; differences due to ability level; and the relationship of lessons to injuries.

The key findings are • The overall rate of injuries in the current study group of ski areas is lower by 20% from where it was in a similar group of ski areas ten years ago (2.7 injuries per 1000 skier visits (SV) currently, versus 3.3 injuries per 1000 SV ten years ago). • The injury rates for male and female skier populations are essentially the same when controlled for ability level; when the two groups are compared on an overall basis (without controlling for the differential distribution of ability within each group), the female rate is about 50% higher than the male rate. • More females than males tend to be at the lower end of the ability scale. • The rate for beginner/novice skiers is about 10 times that of the advanced/expert skier in terms of number of injuries per 1000 SV. • The use of lessons is not associated with a reduced risk of injury in either activity. • The distribution of injuries (for part of body injured), in DH skiing has changed over the past ten years, today there are more knee (was 27.2% of all injuries, now 32.7%) injuries and fewer ankle (was 11.5%, now 6.1%) and lower leg (was 12.6, now 7.7%) injuries. • Over the past ten years, injuries due to twist/bend have dropped from 35.5% to only 26.2%, while injuries due to impact with snow surface have increased from 35.6% to 41.8%. • Fractures have declined from 19.1% to only 13.5% of all injuries.
Children's Skiing Injuries in Victoria, Australia
Authors: Giddings PH , McCallum IG , Duff PA
Published: March 2009

This study reviews 2501 skiing injuries presenting to the Mt. Hotham Medical Centre over a three year period. Of these, 204 involved children 12 years of age or younger. Patterns of injury are compared with the 2297 cases involving skiers 13 years or older.

There was no significant difference in the overall rate of injury between the two groups. The incidence of knee ligament injuries was similar in both groups but the rate of lower leg fracture in children was six times that of adults. Interestingly, thumb injuries were virtually nonexistent in the under 12 group.

These injury patterns suggest that advances made over the last two decades in adult ski boot and binding design have not been reflected in increased lower leg safety for the child skier population.
Organization of Skiing Safety in a New Alpine Area: Injury Severity Score Used to Compare and Classify the Difficulty of the Slopes
Authors: Bergstrøm KA , Askild O , JøDrgensen NA , Ekeland A
Published: March 2009

Hafjell Alpine Center is the new Norwegian Winter Olympic Arena for 1994, and also the national alpine project area. The lift capacity is about 8000 transportations per hour. A total of 770,672 lift transportations and 86 injuries were registered between December 15, 1990 and April 15, 1991. The injury rate was 3.77 ∙ 10 -4 injury per 1000 vertical meters skied or 2.2 injuries per 1000 skier days.

Skiing safety has been established in the new area through a ski school, a shop for ski rental and binding testing, a rescue team based on the ski patrol, and a doctor on call in the alpine center during the crowded weekends.

All skiing injuries were recorded on a questionnaire and the abbreviated injury scale (AIS) and the injury severity score (ISS) were calculated. The ISS was marked on a map of the entire area to spot exactly where the accident occurred. The sum of ISS for each slope and for the whole area was also calculated.

This model proved to be an excellent opportunity to make major and minor alterations on the slopes: flattening and widening the trails by taking out rocks and obstructions, correcting defects, and grooming the slopes for the next day.

The total ISS during the recorded period was 318. A corrected ISS of 345 was related to the total lift transportations and to the total skiing length and the vertical drop. This corrected score may possibly be used to compare the results from one year to another and from one center to the other.
Snowboard vs. Downhill Skiing Injuries
Authors: Shealy JE
Published: March 2009

This study is based upon two ski seasons worth of data from fifteen ski areas in the United States. A total of 21 817 downhill (DH) injuries and 1194 snowboard (SB) injuries occurred during 8.20 million skier visits. The injury data came from Ski Patrol reports. Control groups of 2318 DH and 255 SB skiers were used to estimate demographic characteristics of the populations at risk. The study looks at the differences between DH skiing and SB skiing; differences between control and injured groups of skiers for both activities (DH and SB skiing); differences between male and female skiers; differences due to ability level; the relationship between lessons and injuries; and the biomechanics of snowboard injuries.
Snowboarding Injuries
Authors: Janes PC , Fincken GT
Published: March 2009

A three year nonrandomized clinical study was instituted to ascertain the pattern of injuries sustained by participants of snowboarding.

A total of 874 questionnaires, representing 937 injuries, were collected over the 1988 to 1989, 1989 to 1990 and 1990 to 1991 ski seasons with assistance of 37 physicians who saw patients from seven major Colorado ski areas.

The frequency of lower extremity injuries compared to upper extremity injuries was similar. The difference between lower extremity and upper extremity injuries was not significant by contingency table analysis (P > 0.05). However, 19% of all injuries and 45% of all upper extremity injuries were distal radius fractures. With the exception of the medial collateral ligament (MCL), there were few significant knee ligament or thumb injuries, but a disturbing number of tibia fractures, ankle fractures and ankle sprains, reminiscent of alpine ski injuries prior to the advent of the modern rigid boot [1].

Snowboarding participants appear to suffer different injuries than alpine skiers and possible preventative measures are discussed.
Mechanisms of Fretting-Fatigue and Their Impact on Test Methods Development
Authors: Hoeppner DW
Published: March 2009

At the beginning of this century very little information was available related to the phenomenon of fretting and fretting-fatigue. However, significant progress has been made in developing an understanding of the mechanisms of fretting-fatigue in this century. Progress toward developing a holistic view of the process of fretting fatigue is presented.

Contributions that have been made in understanding nucleation of fretting-fatigue damage are reviewed. As well, characterization of damage is discussed related to improving our understanding. Those parameters that are viewed as mechanism controlling, thus important to test methods development, are reviewed. The progress made in micromechanical modeling is also reviewed. The paper concludes with recommendations for the standards development group to consider in relation to test methods and some suggestions for future research and development.
Determination and Control of Contact Pressure Distribution in Fretting Fatigue
Authors: Sato K
Published: March 2009

Contact pressure is one of the most important factors in fretting fatigue. The contact pressure distribution on loading of applied cyclic stress is markedly different from that on unloading. To elucidate the effect of contact pressure on fretting fatigue strength, the contact pressure distribution should be exactly determined. In this paper, the contact pressure distribution was calculated by using a boundary element method and monitored by an experimental method of caustics. Differences in the contact pressure distribution between the shapes of fretting bridges whose height is 10, 15, 20, and 30 mm at a constant span of 30 mm, and between two types of clamping, which are center clamping and edge clamping at the back face of the bridge, were analyzed. In order to examine the effect of the contact pressure distribution on the fretting fatigue strength, fretting fatigue tests in plane bending were carried out. The S-N properties obtained from fretting fatigue tests could be estimated analytically by equivalent stress amplitude.
Techniques for the Characterization of Fretting Fatigue Damage
Authors: Ruiz C , Wang ZP , Webb PH
Published: March 2009

The factors that determine fretting fatigue damage of a given material pair are relative slip between the two surfaces in contact, shear stress at the interface, and tensile stress that forces the crack, once started, to grow. Three types of test are described: a biaxial loading test for interlocking joints, a uniaxial tension-compression test, and a three-point bending test. It is concluded that the latter is sufficient for most purposes besides having low cost and simplicity.
Adaptation of a Servohydraulic Testing Machine to Investigate the Life of Machine Components Operating under Fretting Conditions
Authors: Labedz J
Published: March 2009

Fretting tests are of considerable practical importance to increase the reliability of machinery and to reduce design costs. They are frequently conducted on expensive, special apparatus. A reduction of outlay on research work is possible through the use of a universal test rig and commercially available equipment. In this paper a fretting test method is proposed using a servohydraulic testing machine.

Tests on the effect of residual stresses on fretting wear of bearing steels were performed for the purpose of verifying the proposed methodology. The test results are compared with data given in other publications which validate the method.
Improving Fretting Fatigue Strength at Elevated Temperatures by Shot Peening in Steam Turbine Steel
Authors: Mutoh Y , Satoh T , Tsunoda E
Published: March 2009

Fretting fatigue tests at elevated temperature were carried out using shot-peened specimens to improve the high temperature fretting fatigue strength of 12Cr-Mo-W-V steam turbine steel. Shot peening improved fretting fatigue strengths by a factor of 1.8 at an elevated temperature (773 K) as well as at room temperature. Residual compressive stresses first drop rapidly by a factor of three and then level off. Residual compressive stresses of 200 MPa were measured after a 30 000 h exposure at 773 K. Shot peening is thus shown to be effective over long periods at 773 K.
The Fretting Fatigue Properties of a Blade Steel in Air and Vapor Environments
Authors: Deng Y , Zhang B , Luo W
Published: March 2009

Fatigue and fretting tests were carried out with 15 Cr 11 MoV steam turbine blade steel in air and vapor environments. The steel was in the as-heat-treated and as-shot-peened conditions. Both testing ambience and shot peened residual stress could effect the fretting fatigue strength of the steel. The AES and Mossbauer spectrometry experiments indicated that the oxide layer in the fretted scar and the debris had different structures, depending on whether they were formed in air or vapor. This resulted in a change in the tribological properties between the contact surfaces and in the fretting fatigue strength of the steel. However, the environmental effects became less important in compressive stresses.
Containment and Regulations for Safe Biotechnology
Authors: Vranch SP
Published: March 2009

The safe use of microorganisms for the manufacture of biological Pharmaceuticals has been demonstrated over several decades. Regulations, guidelines, and codes of practice are already available, and additional guidance is being published by a variety of organizations worldwide.

The implications of these regulations are reviewed and their impact is described using examples of facility, equipment, and process design, with particular emphasis on containment.
Industrial Safety for the Biotechnology Industry
Authors: Keene JH
Published: March 2009

The development of the biotechnology industry has prompted an emergence of a field of safety involving existing procedures and new technologies for protecting employees and the general public. A coordinated effort on the part of diverse corporate entities and the corporate safety committee, directed by professional safety personnel, is required in the development of these new safety programs. Commitment of corporate management to accepting the responsibility for ensuring safe working conditions is essential. Recognition of potential hazards and risk assessments for individual companies are also important. Safety in the biotechnology industry must be viewed as an integral and contributory part of the overall business venture.
General Considerations for Work Practices and Personal Protective Equipment in Biotechnology Industries
Authors: Martinez KF , Elliott LJ , Jones JH
Published: March 2009

Occupational exposures to microorganisms or other potentially hazardous substances related to industrial biotechnology can be controlled by the application of a number of well-known principles of industrial safety, including engineering measures, work practices, personal protective equipment, and feedback on the effectiveness of these controls through the use of industrial hygiene monitoring. This paper focuses on work practices and personal protective equipment observed in industrial settings during studies conducted by researchers at the National Institute for Occupational Safety and Health (NIOSH) on conventional enzyme fermentation processes, early recombinant DNA facilities, and a large-scale land application of a microbial pesticide. In a majority of the situations observed, operator exposures could be reduced dramatically by limiting operator interaction with unit processes or by ensuring the observance of proper and safe work practices. In the plant environment, company procedures appeared to be adequate for minimizing worker exposures. These procedures, however, can only be effective if proper training is provided to the worker and if management ensures that good work practices are continually observed. In the laboratory environment, standard laboratory practice guidelines for microbiological or biomedical agents [available from the National Institutes of Health (NIH), the Centers for Disease Control (CDC), and other agencies], if followed, provide adequate protection to the worker. There are currently no research-supported recommendations for personal protective equipment for use with microorganisms developed on an industrial scale. However, selected pieces of equipment can be suggested which will minimize operator contact (e.g., eye protection, face protection, protective clothing, and other equipment) until more risk assessment research has been conducted.
Safe and Effective Spill Control Within Biotechnology Plants
Authors: Van Houten J
Published: March 2009

Physical containment of biotechnology processes requires the following: (1) the selection of an appropriate fermenter and associated equipment, (2) suitable exhaust gas treatment, (3) consideration of the potential for overpressurization and its subsequent relief, (4) the installation of suitable inoculation and sampling systems, and (5) the collection and inactivation of condensate that may contain viable organisms. When the system is properly operated and adequately maintained, the potential for an unplanned release of viable biological agents is minimal. However, plans must be developed to deal with this eventuality to provide simultaneous employee and environmental protection. Three scenarios that must be considered are spills confined to the interior of a biological safety cabinet, unconfined spills in the open facility, and catastrophic failure of a large fermenter. Each is a unique situation that requires a specialized response by spill cleanup personnel. This paper describes an effective spill control program that is proactive and anticipatory in approach and focused primarily on prevention and secondarily on emergency response.
FDA Enforcement in Bioprocessing Facilities
Authors: Smith B-H
Published: March 2009

Biotechnology is a rapidly developing field. Concerns for the health and safety of workers, for the safety and efficacy of the biotechnically derived products, and for potential environmental contamination have been expressed. With the development of a consistent government-wide policy for the regulation of products derived from new biotechnologies, the United States government has taken steps at agency and interagency levels to dispel these concerns. Under the authority of the Food, Drug, and Cosmetic Act of 1938, the U.S. Food and Drug Administration (FDA) evaluates and regulates the safety of biotechnology-derived products in the same way that it does for conventionally manufactured products. Scientific, safety, and regulatory issues are considered prior to approval for commercial production. Once a product receives approval, enforcement of the laws and regulations at the manufacturing level is accomplished by FDA's field personnel. The individual firm's manufacturing and quality control procedures are reviewed and evaluated to determine if they are in compliance with the Current Good Manufacturing Practice regulations. The FDA believes the current laws provide adequate regulatory protection and are sufficiently comprehensive to regulate products regardless of whether they are manufactured by traditional processes or are the products of biotechnology.
Principles of Design and Installation of Building Deck Waterproofing
Authors: Ruggiero SS , Rutila DA
Published: March 2009

Plaza waterproofing is precarious because of the severe service conditions imposed on the system and the inaccessibility of the waterproofing membrane for repairs. Most systems are covered by a wearing surface that often impedes the drainage of water at the membrane level. The “buried” position of the membrane makes trouble shooting and repair difficult and prohibitively expensive.

This paper presents fundamentals for design and installation of plaza waterproofing systems. Of particular concern is the design of effective system drainage that facilitates the flow of water from the plaza surface, through the various components, and into drains at the membrane level. Adequate drainage is the single most important factor in the long-term performance of any waterproofing system. System design is discussed to establish the parameters for evaluation of specific system components: the wearing surface, insulation, drainage system, waterproofing membrane, building deck, and design of critical flashing details.
Cathodic Protection for Parking Structures
Authors: Swiat WJ
Published: March 2009

Cathodic protection systems for chloride-contaminated reinforced concrete structures have been installed and evaluated since the early 1970s. Until recently, most of these systems have been installed on bridge structures. Since cathodic protection has been recognized as the only method which can stop corroding steel in chloride-contaminated concrete, a variety of cathodic protection components have been developed for use on these structures. Although it is mostly recommended for rehabilitation efforts where chlorides are already present, it has also been used where chloride contamination is anticipated in the future. Research and implementation of cathodic protection systems has been extensively carried out by the Federal Highway Administration. Through this work, cathodic protection system guidelines for bridges are being developed. Guidelines for cathodic protection systems on reinforced concrete parking structure are needed. Unlike bridge structures, parking structures have more complex steel reinforcement schedules, more stringent structural limitations, and are built with a larger variety of differing designs. In addition, the average parking structure typically has far more concrete surface area than the average bridge structure. Structural limitations, design variations, and size of the parking structure require thorough corrosion evaluations to determine the cathodic protection system requirements. To provide the most economical and cost-effective long-term repair, more than one cathodic protection system design and/or material can be applicable to a single structure. This paper discusses design considerations and guidelines for selection of cathodic protection systems and components for parking structures.
Cathodic Protection of Concrete Bridge Members Containing Mild Reinforcing Steel
Authors: Clear KC
Published: March 2009

Impressed current cathodic protection has been successfully used for over a decade to effectively mitigate corrosion of reinforcing steel in chloride-contaminated concrete structures. The problems associated with the corrosion of reinforcing steel in concrete and the validity of cathodic protection are discussed. A comprehensive review of the several types of cathodic protection systems and their component parts which have been used in the last 14 years to minimize salt-induced deterioration of reinforced concrete structures is presented.
Criteria for the Selection of Penetrating Hydrophobic Sealers Used in the Repair of Concrete Parking Decks
Authors: Wohl RL , LaFraugh RW
Published: March 2009

Deterioration of reinforced concrete building decks has developed into a multimillion dollar problem. Penetrating hydrophobic sealers and membrane coatings are available that seal the concrete surfaces and can slow or prevent deterioration. Field and laboratory tests can be used to determine whether or not application of hydrophobic sealers may be effective in limiting leakage and deterioration in trafficked concrete building decks, or if a membrane coating system is required. A typical program for this determination is discussed.
Precast Concrete Pavers for Parking Decks
Authors: Henshell J , Buccellato P
Published: March 2009

Woodhull Hospital is a multistory structure with vehicle parking on an intermediate level. The original paving system failed and was replaced with insulated precast concrete pavers.

The waterproofing/paving assembly design constraints included: allowable dead load, equivalent thermal resistance, overall depth, low headroom, limited access for removal of debris and movement of materials, and restriction of equipment and vehicle loads. Numerous rail posts were further complications.

The system selected consisted of 105 by 210 by 9.37 cm (3 ft, 6 in. by 7 ft, 0 in. by 3 3/4 in.) precast concrete pavers with insulation recessed on the underside. Slabs were supported on continuous rubber strips and installed over an ethylene propylene diene monomer (EPDM) loose-laid sheet membrane.

The new system has been in place since 1984 and is problem free to date. This paper discusses the problems and how they were solved, the elements of the design, and the installation method.
Reflective Cracking and Cold, Liquid-Applied Elastomeric Deck Coating and Membrane Systems: Practical Considerations from Field Observations
Authors: Monroe DC
Published: March 2009

Cold, liquid-applied elastomeric deck coating and membrane systems are widely used for waterproofing concrete structures. Typically these systems are liquid-applied in relatively thin mil thicknesses, bonded continuously to the substrate, and cured to a seamless elastomeric barrier for waterproofing protection. A critical property of these materials is the ability to bridge cracks. These materials may be used as traffic-bearing or nontraffic-bearing systems. In some cases they will be exposed directly to sun and weather and in others they will not. ASTM C 836 and ASTM C 957 describe a laboratory procedure for evaluating the crack-bridging capability of these materials. Field observations suggest some limitations with the use of this test as a predictor of crack-bridging properties, however. A clear understanding of why and how concrete structures crack and the relevance of different types of structural design, the impact of various environmental conditions, as well as the properties and limitations of the waterproofing materials are all essential in avoiding problems associated with structural cracks reflecting through the membrane and allowing water penetration into and/or through the slab.
Performance Requirements for a Successful Suspended Deck Waterproofing System
Authors: Van Wagoner JD , Blue G , LaCosse R
Published: March 2009

ASTM is to be commended for the work it has done establishing performance standards for certain generic materials used in waterproofing applications. These standards are represented in: Specification for High Solids Content, Cold Liquid-Applied Elastomeric Waterproofing Membrane for Use with Separate Wearing Course (C 836), Guide for Use of High Solids Content, Cold Liquid-Applied Elastomeric Waterproofing Membrane with Separate Wearing Course (C 898), Specifications for High-Solids Content, Cold Liquid-Applied Elastomeric Waterproofing Membrane with Integral Wearing Surface (C 957), and Guide for Design of Built-Up Bituminous Membrane Waterproofing Systems for Building Decks (C 981). They detail physical properties desired in the various materials and their application techniques for waterproofing building decks over habitable space.
Crevice Corrosion Resistance of Stainless Steels in Waters Containing Chloride and Sulfate Ions
Authors: Kain RM
Published: March 2009

Crevice corrosion behavior for a series of austenitic and duplex stainless alloys was determined in a number of simple solutions as well as in diluted natural seawater containing up to 10 g/L Cl- and 10 g/L SO4=. Remote crevice assembly technology using zero resistance ammeters revealed differences in initiation and propagation resistance. Effects of solutionion concentration, alloy composition and the influence of crevice geometry and biological activity are discussed.

While S30400 and S31600 were found to be susceptible in all tests considered, other materials (N08904 and S32550), and especially a 6% molybdenum alloy (S31254), were substantially more resistant. Test results indicate some beneficial effects of sulfate at lower levels of chloride. However, at high chloride levels, high sulfate appears detrimental. At comparable chloride levels crevice corrosion was more severe in diluted natural seawater than in synthetic solutions.

This work is part of an on-going study involving additional alloys and more varied water chemistries. The ultimate goal of this research is the preparation of a Crevice Corrosion Atlas for Stainless Steel in Waters.
Corrosion Fatigue Testing of Steels as Applicable to Offshore Structures
Authors: Hartt WH
Published: March 2009

Fatigue is a potentially important failure mode for offshore structures. Development of realistic data (high-cycle regime of the S-N curve or near-threshold region of the crack growth rate-stress intensity range curve) is made difficult by the fact that load excursions are mostly of low amplitude (high-cycle fatigue) with frequency in the range of 0.05 to 0.5 Hz; and so one or more years of testing may be required to establish a single data point (S-N approach) or da/dN-ΔK curve. In the present paper experimental alternatives for developing both fatigue life and crack growth rate data for offshore applications are presented, with particular emphasis upon test parameters and variables of importance. Special emphasis is placed upon techniques for multiple specimen testing. In addition, a novel approach for characterizing near-threshold fatigue crack growth rates within realistic test periods is proposed and discussed.
Corrosion Testing in New York Reservoirs and Investigations of In-Service Corrosion
Authors: Andersen GA , William L
Published: March 2009

Immersion tests of various duration were performed on copper-based alloys,nickel-based alloys, cast irons, and stainless steels. Specimens were exposed at two upstate New York reservoirs as well as in a laboratory environment. The type of corrosion as well as the amount of corrosion varied with heat treatment condition and composition of the sample. All stainless steel samples showed minimal corrosion of any kind except a martensitic grade which exhibited crevice attack with attendant pitting. In-service corrosion of water mains has been also examined. Metallurgical failure analysis of cast iron water mains has revealed waterside corrosion to be only a minor contribution to the cause of failure in a majority of the breaks.
Effect of Ground-Water Composition on the Electrochemical Behavior of Carbon Steel: A Statistical Experimental Study
Authors: Thompson NG , Beavers JA
Published: March 2009

Historically, the study of the effects of environmental variables on the corrosion behavior of metals has been performed by varying a single species at a time. At most, a two or three variable matrix of tests has been performed. In this study, a statistically designed matrix of tests was performed to examine the main-term effects and several two-factor interaction terms of 15 environmental variables present in ground-water solutions on the corrosion behavior of carbon steel. Cyclic potentiodynamic polarization experiments were performed to determine several characteristic polarization parameters. Regression analyses established which of the environmental variables had a statistically significant effect on each of the polarization parameters. The environmental variables were selected to simulate basalt rock ground-water solutions with the emphasis being the application of carbon steel as a high-level nuclear waste container (overpack). It was found that, to accurately describe the effects of ground-water variables, two-factor interaction terms were often as important, or more so, than the main-effect terms. A limitation of the technique is that, with the large concentration ranges used, the design concentrations could not be achieved due to ion interaction; this produced a correlation among factors in the regression model and inaccuracies in the predictions.
Optical Characterization of Transparent Materials Using Ellipsometry
Authors: Nee SF , Bennett HE
Published: March 2009

Refractive indices of transparent materials can be measured with high accuracy on small laboratory samples using null ellipsometry. Measurement precision in both n and k obtained ellipsometrically is ±0.0004 for semitransparent samples. Systematic errors in ellipsometric characterization of optical constants for transparent materials can result from back-surface reflection as well as from front-surface scattering caused by surface roughness. An analysis of the contribution of these errors and the methods of eliminating them are discussed. We conclude that careful ellipsometric characterization can give indices of refraction to three decimal places in the infrared for materials with low k.
Microindentation as a Technique for Assessing Subsurface Damage in Optics
Authors: Polvani RS , Evans C
Published: March 2009

Efforts to optimize precision machining emphasize form and surface finish as the primary objectives. Minimizing subsurface damage is no less important for high power optics. This paper reports our usage of instrumented microindentation for subsurface damage assessments. Our instrument is an example of a new class of diagnostic tool. All apply controllable loadings to an indenter and continuously measure the load and resulting penetration. The utility of microindentation depends on appropriate interpretations of load-depth curves. The technique provides insight into the physical nature of the subsurface and is a means to obtain a variety of engineering properties from the subsurface region. We use it to profile flow stress and elastic modulus with depth, and to gauge creep and anelastic behaviors. Instrumented microindentation promises rapid and sensitive property assessments. We will use a range of examples to show this potential is realizable.
Expanded Damage Test Facilities at LLNL
Authors: Morgan AJ , Rainer F , De Marco FP , Gonzales RP , Kozlowski MR , Staggs MC
Published: March 2009

We are completing a thorough expansion of the laser-induced damage-test capabilities at LLNL which allow us to conduct tests under a variety of parameter conditions. We have nine different laser systems which cover the following parameter space:

LaserWavelength (nm)Max. PRF (Hz)Duration (ns)Peak Fluence (J/cm2)Reptile 11064301065Reptile 2/4532, 266101040, 25Reptile 3355101040Chameleon 31064, 532, 355, 266103> 50Chameleon 101064, 532, 355, 2661010> 50Raster Blaster106417.8860Variable Pulse Laser (VPL)1064Single shot1–100> 70Kilroy106460006510Felix350, 2481002030

We describe details of the physical configurations of the individual systems, laser and sample diagnostics, and general testing procedures and capabilities. Damage test results are presented in a companion paper at this conference — “Laser Damage Database at 1064 nm”.
Laser Induced Damage in Schott's OG-550 Optical Absorption Glass
Authors: Whittaker T , Goedert R , Templeton D
Published: March 2009

Single and multiple shot laser induced damage threshold (LIDT) values were determined for Schott's OG-550 optical absorption glass using Q-switched 532 nm laser radiation. Bulk discoloration occurred for a single shot LIDT of 55 mJ/cm2 while surface pitting resulted at a single shot LIDT of 5.6 J/cm2. Multiple shot LIDTs were determined at 10, 5, and 2 Hz. For all three repetition rates, the multiple shot LIDTs decreased exponentially from the single shot LIDT, and level off at 35% of that value.
Effects of Laser Damage Processes on Microwave Propagation
Authors: Eng RS , Abouzahra MD , Harris NW , Cohn DR , Woskov PP
Published: March 2009

Preliminary analysis has indicated that laser radiation may alter microwave propagation in transparent solids by both electron avalanche and thermally induced plasmas. These effects may occur at fluence levels below that at which visible damage occurs. Temperature rises well below the melting point may create sufficiently dense plasmas to affect propagation. The dependence of propagation effects upon plasma density and size has been modeled. Effects of varying the initial temperature have been studied. Irreversible changes in microwave absorption are also considered. Effects are analyzed for a CdTe microwave modulator for CO2 laser radiation. Plasmas with densities 1015-1016 cm-3 are generated at temperatures 500–700 °C in CdTe. At these densities, microwave propagation may be significantly affected. Microwave measurements of simulated plasmas have been carried out using metallic and resistive materials of different dimensions. Comparison is made with theoretical models. An experimental setup using a high energy pulsed CO2 laser and a sensitive microwave reflectometer for measuring laser induced effects will be discussed.
Laser-Induced Damage to Silicon Photosensor Arrays
Authors: Zhang C-Z , Benchetrit T , Watkins SE , Walser RM , Becker MF
Published: March 2009

Laser-induced damage in two types of silicon photosensor array has been studied. The samples were MOS CCD time delay integration (TDI) sensors with a 2048×96 element array of pixels and CID photodiode arrays of 512×1 pixels. The laser source was a Q-switched 1064 nm Nd:YAG laser (10 Hz rep rate, 10 ns pulses with a 250 μm spot radius). Tests for morphological and electrical damage to the CCD arrays have been reported previously. In new experiments, the micro-damage morphology is examined and correlated with both the observed electrical degradation and newly observed stress effects. We report the observation of surface deformation and lattice defects due to laser-induced stresses in the SiO2 and poly-silicon thin films on the silicon substrate. Measurements of damage for the CID arrays show them to be more resistant to laser damage than MOS structures such as CCD arrays. In addition, electrical degradation of these arrays was observed which affected the video output signal from the devices.
Sensitive n2 Measurements Using a Single Beam
Authors: Sheik-Bahae M , Said AA , Wei TH , Hagan DJ , Van Stryland EW , Soileau MJ
Published: March 2009

We present a sensitive single beam technique for measuring nonlinear refraction in a variety of materials that offers simplicity, sensitivity and speed. The transmittance of a sample is measured through a finite aperture in the far-field as the sample is moved along the propagation path (z) of a focused Gaussian beam. The sign and magnitude of the nonlinearity is easily deduced from such a transmittance curve (Z-scan). Employing this technique a sensitivity of better than λ/300 wavefront distortion is achieved in n2 measurements of BaF2 using picosecond visible laser pulses.
Annealing of Induced Damage in Fluoride Glass Components
Authors: El-Bayoumi OH , Suscavage MJ , De Rochemont LP
Published: March 2009

Heavy metal fluoride (HMF) glasses are of considerable interest for use as multispectral optical components. HMF glass samples of different compositions were prepared and subjected to different doses of gamma radiation at room temperature. Optical absorption measurements showed that strong damage occurred in the UV and visible regions and no significant losses were detected in the infrared region.
The Effect of Laser Annealing on Laser Induced Damage Threshold
Authors: Kerr NC , Emmony DC
Published: March 2009

A significant enhancement of the single shot Laser Induced Damage Threshold of CaF2 and fused silica and a moderate enhancement for GaAs and Al has been observed as the result of laser annealing using an excimer laser operating at 248 nm. This phenomenon is primarily attributed to a reduction of the residual surface roughness of the samples.
Shockwave Detection, An Efficient Way to Determine Multiple-Pulse Damage Thresholds
Authors: Petzoldt S , Elg AP , Reif J , Matthias E
Published: March 2009

The detection of damage associated shock pulses via the deflection of a probe laser beam is exploited to study multiple-shot damage thresholds in CaF2, PMMA, copper, and aluminium. We find a reduction of threshold intensity as compared to single-shot conditions. The experimental results point towards deviations from the previously postulated fluence dependence FN = F1NS-1 [see Ref.4]. They are, however, compatible with a simple model relating the threshold reduction to defect accumulation via non-linear energy absorption.
Application of the Ronchi Ruling Beam Profiling Method to Axially Symmetric Laser Beams
Authors: O'Connell RM , Chen C-H
Published: March 2009

The application of the Ronchi ruling beam characterization method to axially symmetric optical beams is analyzed. Specific results are derived for the Airy and focused annulus diffraction patterns. Plots of the ratio of minimum to maximum transmitted optical power versus the first null radius of the beam functions show that for the Airy pattern and other focused annuli with obscuration ratios smaller than approximately 0.30, the method should be just as useful as with Gaussian beams.
Laser-Induced Failure in Biased Silicon Avalanche Photodiodes
Authors: Watkins SE , Zhang C-Z , Walser RM , Becker MF
Published: March 2009

The characteristics of laser-induced electrical failure in biased silicon avalanche photodiodes have been observed. The samples were RCA reach-through avalanche photodiodes with antireflection coatings. They were biased at typical operating voltages during irradiation. The laser source was a Q-switched 1064 nm Nd:YAG pulsed laser operating at 10 Hz with a 10 ns pulse length and with a 300 μm spot radius.

The current-voltage characteristics were monitored for permanent change as a function of laser fluence and the degradation thresholds were found. Two types of change were observed. The first type was a large increase in bulk leakage current. It may be modeled by the introduction of defects into the depletion region by deep melting transients. The second type was catastrophic failure in which the devices were electrically shorted after irradiation. It may be modeled by excessive current density in the photodiode junction. The type of failure was determined by the parameters of the biasing circuit.
Quantitative Analysis of Surface Trace Metal Contamination on Substrates and Films by TXRF
Authors: Hockett RS
Published: March 2009

The damage to optics from high power laser radiation depends in part upon the surface films on the system optics. Approaches to hardening these surfaces to these types of radiation have focused on layered film compositions and upon the reduction of structural defects in the films and the substrates. The importance of heavy metal contamination at trace levels (less than one thousandths of a monolayer) in the top few monolayers of the surfaces, or at the film interfaces, has been minimized because of insufficient analytical technology to detect these impurities. These localized heavy metals may absorb radiation, ionize to high positive states, and become the source of defects leading to damage. This paper will describe a new analytical technique, Total Reflection X-Ray Fluorescence (TXRF), which is capable of quantitatively detecting heavy metals (Z>11) on the surface (top few nm's) of the substrates or films, with detection limits down to 1011 atoms/cm2 (in most cases several orders of magnitude better than ESCA or AES, and quantitative, in contrast to SIMS.)
An Error Analysis of the Wyko TOPO Noncontact Surface Profiler
Authors: Hodgkin VA
Published: March 2009

An increasingly important tool in the characterization and measurement of optical materials and components in the Wyko TOPO Noncontact Surface Profiler. Optically, it consists of a low- to medium-power microscope in which the objective, depending upon the power, is a visible light interferometer of either Michelson, Mireau, or Linnik design. By integrating a detector array into the viewing system and attaching the reference arm of the interferometer to a piezoelectric transducer, the technique of surface profiling by phase shifting is accomplished by computer.

The potential utility of this system to the investigator interested in the fundamental mechanisms of laser-induced damage is enormous, provided that the user is aware of its proper use and limitations. This paper is intended to act as a user's guide to the TOPO system in such cases and to document its precision and accuracy limitations given a variety of surface types and measurement configurations.
Low Scatter Surfaces on Silicon Carbide
Authors: Paquin RA , Magida MB
Published: March 2009

Reaction bonded silicon carbide (RB SiC) can be readily fabricated to near net shape and mirror blanks produced by this method can potentially be less costly than those fabricated by chemical vapor deposition (CVD). However, RB SiC is two phase, SiC and up to 30% silicon (Si), and can not normally be directly polished to low scatter and roughness levels due to the difference in hardness of the two phases. We have investigated the polishability of RB SiC as a function of Si content and microstructure. Our results show that with a favorable microstructure, RB SiC can be polished to less than 10Å rms. For reduced roughness and lower scatter surfaces, we have developed low temperature deposition techniques to apply polishable, single phase coatings to the figured two phase surfaces. Scatter and roughness measurements show levels are comparable to CVD SiC.
Physical Limits on Ultra-High Albedo Diffuse Reflectors
Authors: Miles P
Published: March 2009

While the theoretical possibility of achieving near-perfect diffuse reflectance in a purely scattering material is longstanding, no attempt seems to have been made to develop scatterers with albedos of 0.999 and beyond. Such ultra-high albedo diffuse scatterers are now of interest because they offer the possibility for the development of shields against high levels of laser radiation.