bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isocyanate Measurement Methods - ISO Standardization
Authors: Brown RH 
Published: April 2008

Historically, a large number of alternative methods have been devised for the measurement of airborne isocyanates. Nearly all these methods rely on the derivatization of the reactive isocyanate groups to products that can be analyzed, usually by some form of chromatography. The choice of an ideal method relies partly on the requirements of the regulatory authorities, but there are also technical considerations concerning the validity and reliability of the various methods and the cost and availability of instrumentation. It would be comforting if we had a consistent body of advice from the regulatory authorities concerned. However, NIOSH (USA) recommends three methods, OSHA (USA) recommends two methods, ASTM (USA) recommends three methods, NIWL (Sweden) recommends one method and the HSE (UK) recommends two methods. All of these methods are different, with the exception of the l-(2-methoxyphenyl)piperazine (2-MP) and the l-(2-pyridyl)piperazine (2-PP) methods, which appear twice.
Can the International Standardization Organization help? Actually, ISO is preparing four technical specifications. First, it is preparing a method based on the 2- MP reagent (ISO/FDIS 16207). Second, it is preparing a method based on the 9-(l- methyl-anthracenyl)piperazine reagent (New Work Item). Two further methods, based on the dibutylamine method and the Iso-Chek™ method have been agreed as potential new work items but have not been balloted yet. So many alternative methods would seem inconsistent with the ISO objective of variety reduction. The reason is that, in addition to having different areas of application, all existing methods have some disadvantages. Thus, a fifth (guidance) standard is being developed which will explain in more detail the advantages and disadvantages of each method and it is hoped, will point to the development of a genuinely universal method.
Work-Related Asthma from Exposure to Isocyanate Levels Below the Michigan OSHA Permissible Exposure Limit
Authors: Reilly MJ , Rosenman KD , Peck JH 
Published: April 2008

This paper examines the characteristics of 261 work-related asthma (WRA) cases exposed to isocyanates reported to an occupational disease surveillance system in Michigan from 1988–1998, and reviews Michigan Occupational Safety and Health Act (OSHA) inspections at 42 of the facilities where they worked. After October of 1993 when the Michigan OSHA program implemented a newer sampling methodology for isocyanates, 42 inspections were conducted in relation to the WRA cases reported. Samples for isocyanates were not collected in one facility. Isocyanate air levels at 40 of the 41 companies where measurements were taken revealed exposures &lt;0.005 parts per million (ppm), as a time-weighted average (TWA). Sampling for isocyanates at one company revealed a level of 0.005 ppm for TDI (TWA).
At 36 of the 42 inspections, similarly exposed co-workers as the index cases completed a breathing symptom questionnaire. Although non-significant, companies were more likely to have co-workers indicate breathing symptoms where the index case reported exposure to one or more isocyanate spills (11 of 13 companies with spills vs. 15 of 23 companies without spills; OR 2.93, 95% CL 0.43-34), and a higher average percent of symptomatic co-workers compared to the companies where the index case reported no spills (23% vs. 16%; OR 1.42, 95% CL 0.99-2.03). Again, although non-significant, there were more MDI-using companies in which at least one co-worker reported breathing problems than TDI or HDI-users (83% vs. 67% vs. 56%; chi-square 2.49, p=0.29). MDI-using companies had a higher average percentage of symptomatic coworkers than TDI-users and HDI-users (23% vs. 15% vs. 14%; chi-square 9.92, p=0.007).
Michigan workers are exposed to isocyanates below permissible exposure limits yet continue to develop WRA. Spills may account for some but not all of these cases. Despite the lower volatility of MDI, co-workers with exposure to MDI were more likely to have respiratory symptoms than co-workers exposed to TDI or HDI. The majority of these 42 isocyanate-using companies (72%) had no medical surveillance program to monitor for worker sensitization. Compliance with OSHA laws, or “being within permissible exposure limits” will not guarantee the prevention of WRA. Effective engineering controls, established spill clean-up procedures, a comprehensive hazard communication program, and a medical surveillance program to identify newly sensitized workers for prompt removal from exposure may help to prevent isocyanate-induced WRA. Further work is needed to determine the relative effectiveness of each of these components in preventing isocyanate-exposed workers from developing asthma.
Isocyanate Exposures in the United Kingdom
Authors: McAlinden JJ 
Published: April 2008

Isocyanates are asthmagens and most studies of occupational exposures to isocyanates have concentrated on inhalation of the vapor or aerosol. However, exposure may also occur through skin contact with the aerosol or during the handling of liquid isocyanates. Prolonged contact may lead to irritation or contact dermatitis.
Isocyanates are not produced in the United Kingdom (UK). UK industry, however, currently imports between 90000 and 100000 tonnes of isocyanate per year. Isocyanates are widely used in the UK for the manufacture of flexible and rigid foams, fibers, coatings such as paints and varnishes, and elastomers. The UK industry occupational population potentially exposed to isocyanates is about 25000 workers and the overall use of isocyanates by UK industry is increasing slowly.
Traditionally, the occupational group considered to be most at risk from isocyanate induced occupational asthma is spray painters in the motor vehicle repair industry. Because of this, HSE has undertaken campaigns, targeted specifically at the motor vehicle repair industry, to identify how, why and for how long workers are exposed to isocyanates. The findings are discussed in this paper.
The distribution of cases of occupational asthma throughout UK industry by occupation and agent as reported to two UK occupational health databases over the last ten years are also discussed in this paper. Findings are then compared against industry's own occupational health data and sector population breakdowns. Consideration is also given to whether an underlying UK trend of increasing non- occupational asthmas could also influence the reporting of work-related cases.
Field Evaluation of a Gravimetric Sampling Method as a Screening Tool for the Monitoring of Airborne Isocyanates in Paint-Spray Operations
Authors: Norton WW , Dharmarajan V 
Published: April 2008

The industrial applications of polyurethane coatings have been steadily growing. The reaction of polyisocyanates to polyols is the basis for all polyurethane coatings. The Oregon State OSHA PEL for HDI-polyisocyanates is 0.5 mg/m3 8-hour TWA and 1.0 mg/m3 ceiling. The recommended impinger sampling method for HDI-polyisocyanates is cumbersome and potentially hazardous.Previous comparisons of impinger versus filter sampling in paint spray environments have shown that the filters can underestimate the polyisocyanate concentration. However, a recent NIOSH study concluded that an upper limit for the isocyanate concentrations in a paint-spray environment could be measured/calculated by a gravimetric method.In this study, a PVC-filter gravimetric method was compared to an impinger-sampling method for measuring isocyanate concentrations during spray painting of automobiles. Seven side-by-side impinger and gravimetric sample sets were collected inside a custom-made chamber from a 2-gal plastic bottle. Each set consisting of four impingers and four filter cassettes with the same inlet orientation was mounted symmetrically inside the chamber. Tygon® tubing passing through the base connected the samplers to battery-operated pumps outside. Additionally, a vacuum pump connected to five holes at the base permitted the paint spray to be drawn into the chamber at isokinetic velocity.Gravimetric samples were weighed with a precision analytical balance. Impinger samples were analyzed for isocyanates by a standard HPLC/UV method. The gravimetric weights were converted to isocyanate weights using a factor based on the paint formulation. The average isocyanate concentrations in mg/m3 by the two methods were statistically compared. The average ratio of gravimetric measurements to impinger measurements was 1.06 ± 0.15 % for n = 6 (total 48 samples). The gravimetric isocyanate concentrations are the theoretical maximums for the paint atmosphere sampled, whereas, the impinger isocyanate concentrations are the true in-situ values. The predictable correlation between the two methods suggests that the gravimetric method could serve as a screening tool for monitoring isocyanates in validated paint atmospheres.
Use of Air-Purifying Respirators for Substances with Limited or Poor Warning Properties
Authors: Corbitt SM , Heger EA , Sarvadi DG 
Published: April 2008

In 1998, the Occupational Safety and Health Administration (OSHA) updated its general industry respiratory protection standard, 29 CF.R. § 1910.134. The use of airpurifying respirators (APR) was affected by a significant policy change that requires employers to provide respirators equipped with a NIOSH certified end-of-service-life indicator (ESLI) for the expected contaminant, or to implement a change schedule for canisters and cartridges based on objective data showing that the cartridges are effective in preventing exposure to the contaminant, and have an adequate service life.
However, questions continue to be raised about the permissibility of using APR in certain industrial applications where workers may be exposed above allowable limits to substances with poor warning properties. This paper outlines some of the important considerations such as: what data are necessary to demonstrate that the respirator cartridge/filter is quantitatively effective at removing the contaminant of interest, and what data are needed to demonstrate that employee exposures to a contaminant are within the range that the respirator can effectively remove it from the inhaled air stream. These considerations must be taken into account to assure that APR are properly selected and used to provide protection against substances with poor warning properties. Methylenediphenyl diisocyanate (MDI) and polymeric products made from MDI will be used as an example in this discussion.
On The Reasons That Make Bench Tests Unrealiable
Authors: Mizuhara K , Tomimoto M 
Published: April 2008

It is well known that the wear rates of materials evaluated in bench testers are fairly reproducible. However, the performance of the materials obtained in bench tests and practical uses were sometimes completely different from each other. This paper discusses the reasons for such discrepancies observed in hydraulic pump testing in terms of the test conditions and the response of the fluid to them. By analyzing the test condition that reproduced the pump wear in bench tests, it is suggested that at lower temperatures and pressures, the behavior of the fluid at higher temperatures and pressures could be reproduced. Then it is concluded that applying the estimated load and sliding velocities in actual pump to bench tests that use different contact configuration may cause the erratic results. It is also concluded that estimating the phenomena governing the performance in an actual pump is one of the keys to conducting useful bench tests.
The factors that affect the test results and the usefulness and limits of the bench tests are also discussed.
True Characteristics of Strength and Ductility for Neutron-Irradiated Metals and Alloys
Authors: Maksimkin OP , Tivanova OV 
Published: April 2008

The results of comparative investigations of variations in engineering and true characteristics of strength and ductility for austenitic stainless steel 12Crl8NilOTi, high-nickel alloy 03Cr20Ni45Mo4, and commercially pure molybdenum irradiated by neutrons in the WWR-K reactor core at a temperature lower than 370 K and the fluences ranging from 5.1022 to 2.1024 n/m2 (E&gt;0.1MeV) are presented.
In tensile experiments at 293 K at the constant strain rate ~10-4 c-1 the curve showing variations in geometrical dimensions of specimens was recorded together with the strengthening diagram. This revealed regularities in deformation-induced change of specimen diameters measured at various cross-sections over the specimen operating length, and allowed us to determine true values of the yield strength and the failure stress, and to find the value of narrowing related to the start of the localized plastic deformation.
For steel specimens, true values of strains and stresses (with the specimen diameter and length variations taken in account), corresponding to onset of recording the martensite ferromagnetic phase, are determined. It has been shown that, under the present test conditions, true stresses of á-phase formation in deformed steel are found to decrease as the neutron fluence increases.
The Swelling Dependence of Cold Worked 16Cr-15Ni-2Mo-lMn Steel on Neutron Irradiation Temperature, Fluence and Damage Rate During Its Use as a Cladding Material in the BN-600 Reactor
Authors: Kozlov AV , Kinev EA , Bryushkova SV , Portnykh IA 
Published: April 2008

The radiation swelling of samples of fuel element cladding made of steel 16Cr-15Ni-2Mo-lMn after its use up to a maximum damage dose 73 – 93 dpa in the reactor BN -600 was studied. The samples were cut out from areas of different location in the core, so the irradiation temperature of various samples varied from 390 to 610 °C. The damage dose varied from 40 –92 dpa and the radiation damage rate varied from 0.9 ∙ 10-6 to 2 ∙ 10-2 dpa/s.
The conditions necessary to have the radiation swelling occurred were considered theoretically within the statistical thermodynamics of solids. An analytical expression connecting the incubation period of swelling with a temperature, fluence, radiation damage rate, and characteristics of material microstructure was obtained. The swelling rate at the post-incubation stage at various irradiation temperatures was estimated. The character of swelling dependencies on temperature, dose, and radiation damage rate obtained from the experimental data agreed well with the results of the theoretical analysis. In the range of 390 to 600 °C the nucleation damage dose initiating swelling increased with irradiation temperature. The swelling rate in the post-incubation phase also increased. Decreasing radiation damage rate shifted the fluence dependence of swelling into a region of lower fluences and temperatures.
High-Energy Spallation Neutron Effects on the Tensile Properties of Materials for the Target and Blanket Components for the Accelerator Production of Tritium Project
Authors: James MR , Maloy SA , Sommer WF , Johnson WR , Lohmeier DA , Hamilton ML 
Published: April 2008

The Accelerator Production of Tritium (APT) project proposes to use a 1.0 GeV, 100 mA proton beam to produce neutrons by spallation from a tungsten target clad with Alloy 718. The neutrons are multiplied and moderated and then captured in 3He to form tritium. In this process, the materials in the target and blanket (T/B) region are exposed to a wide range of irradiation conditions. To test the effects of spallation neutrons on APT candidate materials, ASTM subsize samples were irradiated in a spallation neutron spectrum created from the interaction of an 800 MeV, 1 mA proton beam on a tungsten target at the Los Alamos Neutron Science Center (LANSCE). Specimens were located in controlled-temperature furnaces that were placed in proximity to the proton beam, but in locations where spallation neutrons would form the bulk of the exposure. The materials irradiated were the candidate APT materials 316L and 304L annealed stainless steels (SS), modified 9Cr-1Mo steel, and Alloy 718 (precipitation hardened). Irradiation temperatures varied from 100 to 280 °C and the approximate proton fluences were 4 × 1018 p/cm2. The neutron fluences were ∼5 × 1019 n/cm2 for energies &lt; 0.1 MeV and 6×1019 n/cm2 for energies &gt; 0.1 MeV with the spectra including a high-energy tail up to the proton beam energy (800 MeV). The samples experienced an exposure range of 0.023 to 0.051 dpa.
The tensile tests were conducted in air at ambient temperatures (∼20° C). The results indicated that even for low exposures (&gt; 0.05 dpa), there was a decrease in ductility for the all of the alloys. Increases in yield and ultimate strength were observed in the austenitic stainless steels and the 9Cr-1Mo alloy. The Alloy 718 showed no change in yield strength but a marked decrease in the ultimate strength. The results are discussed and compared with results of the in-beam irradiated materials where smaller S-1 type tensile samples were used. Comparison also is made with irradiations of materials in fission environments in a similar dose and temperature environment.
On the α+γ↔γ-Phase Boundary in Nickel and in Manganese Containing Stainless Steel Alloys
Authors: Schüle W 
Published: April 2008

The α-ferrite-phase in nickel and in manganese containing stainless steel alloys is very brittle. Its formation is connected with a huge decrease in volume, which also causes stresses in the alloys that are very dangerous if the materials cannot accommodate them. The α-ferrite-phase is formed in stainless steel alloys only if nucleation sites are provided, α′-martensites are nucleation sites for the formation of α-ferrite, even at temperatures at which α-ferrite is not stable. If α′-martensite is dissolved during an anneal, no new α-ferrite is formed, and the remaining α-ferrite transforms back into γ-austenite.
In “pure” nickel or in “pure” manganese containing stainless steel alloys the martensitic temperature is above 100°C and thus α′-martensite is always present at ambient temperature in these materials, giving rise to the formation of α-ferrite during a subsequent anneal. It was established in the present work that the γ↔γ+α-phase boundary in iron-chromium-nickel alloys is also almost independent of the temperature as in iron-chromium-manganese alloys. Thus the existing phase diagram for nickel containing stainless steels has to be revised. The various elements added to “pure” stainless steel alloys, as we find them in EUR-316L, US-316L, US-PCA, and in AMCR, cause a drastic decrease of the martensitic temperature so that neither α′martensite nor α-ferrite is found in these alloys.
However, in all these four alloys α-ferrite is formed readily during irradiation with high energy particles and a tentative γ↔γ+α-phase boundary, valid during irradiation with high energy particles, is derived. The amount of α-ferrite formed during irradiation increases with decreasing irradiation temperature and with decreasing applied stress. The alloys EUR-316L, US-316L, US-PCA, and AMCR do not survive one reactor cycle, if irradiated at 100°C.
Hydrogen and Helium Gas Formation and their Release Kinetics in Tungsten Rods after Irradiation with 800 MeV Protons
Authors: Oliver BM , Garner FA , Hamilton ML , Sommer WF , Maloy SA , Ferguson PD , James MR 
Published: April 2008

In the Accelerator Production of Tritium Program, thermalized neutrons produced from multiplication and moderation of spallation neutrons will be absorbed in 3He gas to produce tritium. The spallation neutrons will be generated by the interaction of high energy (∼1 GeV) protons with solid tungsten rods. An unavoidable byproduct of the spallation reactions is large amounts of helium and hydrogen gas generated in the rods. The release kinetics of these gases during various proposed off-normal scenarios involving loss of coolant and afterheat-induced rises in temperature are of particular interest. In addition, the magnitude of the gas generation cross sections and the fractional retention of these gases is necessary for extrapolation of these data to higher exposures.Tungsten rods irradiated with 800 MeV protons in the Los Alamos Neutron Science Center (LANCE) to rather high exposures have been sectioned to produce small specimens suitable for measurement of both helium and hydrogen. Hydrogen evolution was measured both by dropping the specimen into a small ceramic crucible at 1200°C and also by subjecting the specimen to a simulated temperature ramp from ∼200 to ∼1200°C, as has been calculated to be induced by loss of cooling and subsequent afterheat in an APT plant. The latter technique showed four distinct hydrogen release peaks at temperatures of approximately 500, 800, 1000 and 1200°C, suggesting a variety of trapping sites with different binding energies. Helium release and total content were easured by subjecting the specimens to the same temperature excursion, followed later by melting to release the remaining helium. Approximately 99% of the helium was retained until melting occurred. For both gases, release measurements were conducted using mass spectrometric techniques.The measured amounts of helium agreed well with predictions. The hydrogen measurements were somewhat lower than predicted. This may reflect diffusional losses from the rods or some needed modifications in the evaporation model employed in the LAHET code.
Asphalt Concrete Smoothness Incentive Results by Highway Type and Design Strategy
Authors: Delton J , Li Y , Johnson E 
Published: April 2008

The Arizona Department of Transportation (ADOT) implemented an incentive/disincentive asphalt concrete (AC) smoothness specification in 1990. Since then hundreds of projects have been tested for smoothness. These projects have included a wide variety of layer combinations of one or more of the following: overlay, remove, replace, and finishing course. The number of projects and variation in design allows comparisons of the smoothness results for different design strategies as well as trends in smoothness results over time. In addition to the tests on the final surface, many projects were also tested on intermediate lift surfaces.
A statistical analysis of the smoothness data is conducted to study the smoothness distribution and to compare the pavement smoothness of different categories. The smoothness correlation between various layers is also studied. The economic benefits of the implementation of ADOT's smoothness specification are evaluated. The results of this study can be useful in establishing target levels for newly implemented or revised pavement smoothness specifications.
Smoothness Index Relationships for HMA Pavements
Authors: Evans LD , Smith KL , Swanlund ME , Titus-Glover L , Bukowski JR 
Published: April 2008

A recent Federal Highway Administration survey indicated that 48 states and Puerto Rico use smoothness specifications for hot-mix asphalt (HMA) pavement construction. As this is a relatively new concept, many states have adapted the Portland cement concrete pavement specifications of Profile Index using the standard 5-mm blanking band (PI5.0) for use on HMA pavements. However, PI5.0 may not provide a reproducible or portable smoothness measure for HMA pavements because of the technical limitations of the equipment and procedures.
The International Roughness Index (IRI) or the Profile Index using a 0.0-mm blanking and (PI0.0) seem to provide a more repeatable and portable smoothness standard. However, one barrier to more widespread implementation of these new smoothness standards is the lack of objective, verifiable correlation methods for use in establishing specification limits using the IRI or PI0.0. Assistance in selecting appropriate IRI and PI0.0 specification limits is needed to provide a basis for modifying current specifications to these more reproducible and portable smoothness indices.
This research effort has developed a relationship between IRI and PI that can assist in transitioning to a reproducible and portable initial IRI or PI0.0 smoothness specification for HMA pavement.