bluuebunny/crossref_metadata_2025 huggingface dataset:
An Aqueous Fine Clean Process for Rocket Engine Hardware
Authors: Becker JF , Shoemaker MC
Published: March 2009

An aqueous fine clean process has been developed for large-scale, complex rocket engine hardware required to meet a cleanliness level of less than 10 mg/m2 (<1 mg/ft2) nonvolatile residue (NVR) and no particles greater than 400 μm in any dimension. The hardware must be compatible with oxygen over the parameter range of liquid oxygen at -160°C (-256°F) and 61 MPa (8800 psi) to gaseous oxygen at +704°C (+1300°F) and 31.5 MPa (4570 psi).

The complete cleaning cycle is comprised of a preclean operation, fine clean, and verification. The aqueous fine clean process developed is a two step operation using a nonionic surfactant diluted in deionized water as a prerinse followed by a final rinse of fresh deionized water. A nonionic surfactant was selected to minimize corrosion and to meet current NASA specification requirements.

The cleanliness of hardware surfaces in this study was determined by analyzing the effluent from flushing with ambient temperature 1, 1, 1-trichloroethane (TCA) in a 30 000 Class cleanroom. The particulate matter was determined by filtering the TCA using a 0.45 μm filter and the NVR was determined by gravimetric procedure. Oxygen compatibility was determined by testing in ambient pressure liquid oxygen at -160°C using an impact energy of 10 kg-m.
“Witness Coupon” Testing as a Possible Method for Validating Precision Cleaned Hardware in Oxygen Systems
Authors: Williams MK , Jones JF
Published: March 2009

In the effort to replace Chlorofluorocarbons (CFCs) in the cleaning and validation processes of precision cleaned hardware, many methods have been proposed. “Witness coupon” testing is one of those methods being studied that would give flexibility to either a cleaning or validation process, and also allow for flexibility in analytical techniques. A precontaminated coupon is processed along with the parts/components and contamination remaining on the coupon is evaluated by an analytical technique. In this preliminary study, infrared specular reflectance is used to evaluate the contamination level on coupons.
Laboratory and Robot Wear Test Selection for Computer Peripherals
Authors: Bayer RG
Published: March 2009

This paper discusses unique wear tests used to address wear problems in computer peripherals. These examples include some for which tribometers were developed and others which involved the use of modified machines or machine sub-assemblies. The former type tests are referred to as laboratory wear tests; the latter, robot wear tests. Several of the tests are related to the wear associated with paper, printer ribbons, and magnetic tape. Because of the low wear resistance of these materials, special test configurations are required to characterize the wear resistance of much harder materials to wear by these materials. Tests, used to addressed conditions of sliding, combined impact and sliding, and combined slip and rolling in computer applications, are also described. The correlation of these tests with field performance, the modification of these tests for different types of materials, and the relationship of these tests to engineering wear models are discussed. The general methodology that was used in the development and selection of these tests is also presented. These tests were used in several ways to support machine development and product engineering programs associated with impact and non-impact printing, check sorting, magnetic recording, and electronic packaging. One was to determine wear coefficients needed for wear life projections of components and designs. A second was the ranking of materials in terms of their wear resistance to support material selection. A third was the evaluation of the effects of different design parameters on wear, such as alignment, roughness, shape, and load.
Realizing Bench Test Solutions to Field Tribology Problems by Utilizing Tribological Aspect Numbers
Authors: Voitik RM
Published: March 2009

This paper will explore the path from the field wear problem to the bench test solution. The perspective will be from that of the product designer who is experiencing a wear problem in the field. Attention will be given to extracting the necessary key information in the field problem to assist in the subsequent testing steps. A tribological code is developed to facilitate the transition from the field problem to the bench test.

The impact of the selection of contact geometry will be reviewed relative to the various test machines which are available. This is more complex today since there are many test machines and many of the test machines utilize adapters which permits a multitude of test geometries. Many special test variations have been developed over the years and these will be discussed to show the broad spectrum of testing opportunities which exists. Consideration of all the test parameters relative to accelerated tests will be reviewed.

The techniques of initial exploratory tests prior to starting the test program will be reviewed relative to the field problem and the proposed test conditions.

Interpretation of the test results will be explained for several test examples.
Extreme Pressure and Anti-Wear Properties of Lubricants: A Critical Study of Current Test Methods and Suggestions for the Future
Authors: Plint MA , Alliston-Greiner AF
Published: March 2009

The most widely used standard tests for the evaluation of wear and extreme pressure properties are analysed in terms of eight tribological parameters. Wide variations in the test conditions are disclosed and the over-riding influence of thermal conditions on test severity is made clear. The relation between tests, such as the Timken, in which one of the two rubbing surfaces is static, and gear or cam and follower tests in which both specimens move, is explored. A preliminary account is given of a new test procedure evolved as a result of the study.
The Miller Number — A Review
Authors: Miller JE , Miller JD
Published: March 2009

An accumulation of facts and effects observed during twenty five years and over 700 Miller Number Tests by White Rock Engineering using the procedure in ASTM G75-89 Test Method for Determination of Slurry Abrasivity (Miller Number) is presented. Included is a discussion of 33 factors that could affect the Slurry Abrasivity Test results and how influential they may be. Probably the most surprising anomaly was the discovery that particle size of segregated sand samples do not always exhibit the rule that fine or small particles are less abrasive. The description of an accepted shortened test time and a newly designed specimen holder which can be applied on older machines is included.
Preliminary Assessment of Radiation Control Coatings for Buildings
Authors: Anderson RW , Yarbrough DW , Graves RS , Wendt RL
Published: March 2009

Radiation Control Coatings (RCCs) applied to external building surfaces can reflect about 85 percent of the solar heating from the surfaces of buildings. Since in warm climates, solar heating is the primary source of heat gain through walls and roofs, RCC technology represents an alternative or adjunct to conventional thermal control methods (e.g. thermal insulation) for opaque building components.

The primary objectives of this project were to: (1) obtain solar and infrared reflectance data for representative RCC products, (2) evaluate test methods for measurement of the radiative properties of RCCs; (3) calculate the changes in heat flow attributed to RCCs in flat roof applications in several geographic locations; and (4) compare field tests and calculated thermal performance of an RCC in a flat roof configuration.

Data are presented for the reflectance properties of five commercially available RCC products as determined by several test methods. The potential energy benefits of RCCs are presented for flat roofs in both warm and cold climates.
The Use of Economic Analysis in Developing an Energy Standard: Lessons Learned
Authors: McBride MF
Published: March 2009

Development of energy standards in the early 1970's was initiated and accelerated by the “energy crisis”. Criteria were proposed based on “professional judgement” and accepted when “consensus” was reached. That process performed a valued service but the conditions have since changed. Today, energy conservation is not a single focus point. It is constantly being challenged as to whether it is cost-effective. In that environment development of new energy standards has incorporated economic analysis as a basis for setting the criteria. The objective of this paper is to present the economic basis used to develop the proposed ASHRAE Standard 90.2P. The traditional life-cycle analysis approach was simplified by development of scalar ratios as a new technique. A national energy model was developed which integrated scalar ratios to illustrate the interdependence between economic assumptions and energy savings. This entire process was new and innovative, which challenged prior concepts and conventional procedures. Many lessons were learned and their influence on the standard development will be highlighted.
Energy Code Measures to Assure the Effectiveness of Thermal Insulation Installed in Buildings
Authors: Nelson BD
Published: March 2009

Several common residential construction details are detrimental to the performance of installed thermal insulation. Degradation of insulation performance is caused by air exfiltration (convective losses and moisture gain in insulated cavities) and wind wash (the passage of outdoor air through insulation).

Existing model energy codes in the United States address the exfiltration issue, although enforcement appears to be only partially effective. U.S. model energy codes do not address wind wash. New provisions of the Minnesota Energy Code for residential buildings are intended to require construction details that would reduce exfiltration and wind wash. The language addressing these construction details is generally more prescriptive than in existing model energy codes.

The inclusion of language in residential energy codes to improve the performance of thermal insulation follows the lead of special programs' building standards for energy efficient construction.
Fundamental Aspects of Thermal Conductivity Aging and Dimensional Stability of Rigid Polyurethane Foams
Authors: Smits GF , Thoen JA
Published: March 2009

One of the possible alternatives to eliminate the future use of CFC-11 as an essential blowing agent in rigid polyurethane foams, consists of a partial or complete replacement by carbon dioxide. The two major problems associated with the use of high levels of CO2 are first, a significant deterioration of thermal insulation capacity with time, and second, a potential loss of dimensional stability due to the rapid effusion of CO2. The paper gives an overview of the scope and limitations of this approach based on the results of extensive computational analysis and simulation.
Thermal Performance of One Loose-Fill Fiberglass Attic Insulation
Authors: Wilkes KE , Wendt RL , Delmas A , Childs PW
Published: March 2009

A series of experiments on one commonly available loose-fill fiberglass attic insulation has been performed using the guarded hot box capability of the Large Scale Climate Simulator at the Oak Ridge National Laboratory. These experiments were conducted using an attic test module that was built to simulate typical residential construction. Under simulated winter conditions, the surface-to-surface thermal resistance between the bottom of the gypsum board and the top of the insulation was found to decrease substantially as the surface-to-surface temperature difference increased from 10 to 40 K. At the largest temperature differences, the resistances were as much as a factor of two lower than the estimated nominal thermal resistance of the insulation. This change in thermal resistance has been attributed to natural convection within the insulation. It should be noted that the present experiments were performed with one type of loose-fill fiberglass insulation, and the results may not be applicable to other loose-fill insulations with different air flow and thermal properties. A series of experiments was also performed with various materials laid on top of the insulation. The most effective of these covering systems produced increases in thermal resistance of more than 100 percent at the largest temperature differences, and appeared to nearly eliminate heat transfer by natural convection in the temperature range investigated.
Hot Box Instrumentation, Calibration and Error Estimation — A Survey
Authors: Miller RG , Goss WP
Published: March 2009

A survey questionnaire dealing with instrumentation, calibration and error estimation of guarded and calibrated hot boxes was mailed to United States and Canada hot box laboratories capable of measuring the R-value of building assemblies. Questions pertaining to types of instrumentation, estimated accuracy of the specific instruments and error analysis calculations were asked. Responses from those laboratories responding to the survey are summarized in the paper. This information will be beneficial to future revisions of the ASTM guarded and calibrated hot box test methods.
Comparison of Heat Transfer Modeling with Experimental Results for Residential Attic Insulations
Authors: Gorthala R , Roux JA , Levins WP , Wilkes KE
Published: March 2009

A heat transfer model was developed for fibrous insulations typically used in residential attic applications. The model predictions were compared with the experimental results obtained at the Oak Ridge National Laboratory for the three Karns Research Houses located near Knoxville, Tennessee. The model was comprised of one-dimensional coupled conduction and radiation heat transport; the unsteady energy equation and radiative transport equation were solved simultaneously. A control-volume-based finite-difference scheme was used to solve the energy equation. The radiative transport equation was solved by the method of discrete ordinates which was inherently required for solving the energy equation. Standard R-30 fiberglass insulation batts without a foil radiant barrier were studied for both summertime and wintertime conditions. The predicted heat fluxes were in good agreement with the experimental heat flux data for the entire one week period for both summer and winter. A key point of this paper is the comparison of the theoretical results with the experimental data for a week's period which has not been attempted previously.
Combined Conduction, Radiation Heat Transfer and Mass Transfer in Fibrous Attic Insulations
Authors: Gorthala R , Roux JA , Fairey PW
Published: March 2009

A numerical model to study heat transfer in an attic insulation has been developed. This model comprises combined conduction, radiation, and moisture transport. The one-dimensional energy equation, radiative transport equation and species equations for liquid H2O and vapor H2O were solved simultaneously. A control volume based finite difference method was used to solve the energy equation and the species equations. A quasi-analytical technique (method of discrete ordinates) was used in solving the radiative transport equation. Standard fiberglass insulations with and without a foil radiant barrier were modeled. Heat transfer results were compared with the experimental data measured at the Florida Solar Energy Center. Predicted heat fluxes agree with measured fluxes quite well. All the cases studied with moisture present were also studied for the dry cases (no mass transfer) and the results were compared. Results with moisture being included indicate that heat transfer from the attic into the house decreases for fiberglass insulations during summer as compared to dry insulation.
Moisture Diffusion in Thermal Insulating Materials
Authors: Freitas V , Crausse P , Abrantes V
Published: March 2009

The moisture behaviour of building materials, especially the kinetics of wetting and drying, is very important because it can influence the hygrothermal performance of the building envelope and the internal comfort.

The mathematical model of heat and mass transfer, in porous media, proposed by LUIKOV — PHILIP and DE VRIES shows that moisture migration, in isothermal conditions, is a function of the humidity gradient and the moisture diffusivity coefficient. This paper reports values of moisture diffusivity coefficients for some thermal insulating materials and how these are calculated. The results of numerical simulation of drying of these materials and a comparison with the data obtained from measurements using gamma-ray spectroscopy in the determination of the moisture distribution are also presented.
The Effect of Exterior Insulating Sheathing on Wall Moisture
Authors: Tsongas GA
Published: March 2009

For some time the impact of the use of rigid foam exterior insulating sheathing on moisture levels in residential wood-frame walls has been uncertain. Recently a field study of 86 newly-constructed Washington and Montana homes was completed that provides clear evidence. Measurements were made of the moisture content of wood members within the wall cavities, almost one-third of which had exterior insulating sheathing. Unacceptably high moisture levels were measured in the walls of a large percentage of the test homes. However, the use of exterior insulating sheathing was found to greatly reduce wall moisture levels. Furthermore, the higher the R-value of the sheathing, the lower were the wall moisture levels. Those walls were found to be drier because the insulating sheathing keeps the wall cavity wood members warmer and also because the sheathing is an excellent exterior moisture barrier or break that keeps wet siding from transmitting or wicking moisture into the wall cavity better than other exterior moisture barriers. Moisture entry from the outside, called “splashback,” is an extremely important and common wall cavity wetting mechanism that heretofore has not been widely recognized. The results of this study indicate that the use of exterior insulating sheathing is one way of providing additional wall insulation while at the same time reducing the potential for wall moisture problems.
Thermal Conductivity of Several Concretes as a Function of Moisture
Authors: Ashworth T , Ashworth E
Published: March 2009

A simple laboratory system for measuring thermal conductivity has been developed which utilizes a heat-flux transducer on each side of the specimen. Because previous studies have characterized the thermal contact resistance, the need to embed temperature sensors in the specimen was avoided. The specimen can be sealed in a plastic bag. This enables measurement of the thermal conductivity of specimens with varying amounts of moisture. Four different concretes have been studied: a standard concrete, a micro-concrete used for model structural analysis, a standard shotcrete with metal fibers, and a foamed light-weight (cellular) shotcrete. Thermal conductivity increased linearly with moisture up to high moisture levels; the values at 27°C range from 1.00 to 1.85 W/(m-K) for concrete, 1.46 to 2.03 W/(m-K) for microconcrete, 0.98 to 1.83 W/(m-K) for shotcrete, and 0.14 to 0.36 W/(m-K) for cellular shotcrete. Data have a reproducibility of better than 2%. The conduction processes in the materials are discussed briefly.
Thermal Insulation Under Fire
Authors: Schultz N
Published: March 2009

This paper describes the different fire and flammability tests where thermal insulations are required to pass by various legal bodies, and all the proposed future test requirements. Insulation manufacturers, engineers, architects and contractors should be aware of the current test requirements in this technology, thus enabling them to provide a thermal insulation system that can meet the total spectrum of requirements including the ones for fire and flammability. The standard used to test for fire resistance in building construction is ASTM E 119 “Fire Tests of Building Construction and Materials.”
Intra-Laboratory Comparison of a Line-Heat-Source Guarded Hot Plate and Heat-Flow-Meter Apparatus
Authors: Zarr RR
Published: March 2009

The apparent thermal conductivity and thermal resistance of several building insulations were determined at the National Institute of Standards and Technology (NIST) using three apparatus. Reference values were determined with NIST's 1-metre Line-Heat-Source Guarded Hot Plate (GHP). The other two apparatus were heat-flow-meter (HFM) apparatus calibrated with a Standard Reference Material of fibrous-glass board (138 kg/m3). The apparatus — NIST's 1-metre GHP; the 610 mm HFM; and the 305 mm HFM — were operated at a mean temperature of 24°C and temperature difference of 22°C across the thickness of the specimen. Measurements of thermal conductivity were determined for individual specimens nominally 25 mm thick, covering a range of thermal conductivity from 0.02 to 0.16 W/(m∙K). The thermal resistance of thick specimens (1 to 7 m2∙K/W) of cellular plastic, fibrous and loose-fill insulation was also determined. Deviations from reference values of the GHP were calculated for the HFM apparatus. For the 610 mm HFM, the majority of deviations were within ±3% of the GHP. Substantial improvement was achieved by calibrating the 305 mm HFM as a function of thickness; however, deviations ranged from +1.5 to +9.2% from the GHP. The apparatus, test procedure, and analysis of the deviations are described in the paper.
A Round-Robin Comparison of Australasian Thermal Laboratories
Authors: Trethowen HA , Desjarlais AO
Published: March 2009

This paper describes a comparison of seven laboratories in Australia and New Zealand, and one US laboratory, involved in testing thermal properties of materials. The primary objective of this Round Robin was to establish or confirm what degree of confidence can be placed in measurements by the various laboratories in this region. It was carried out using two industrial insulant products which were premeasured. Three samples were sent to each participant, who each conducted four thermal resistance measurements.

Results were typically within ±6% of the mean value, with a worst-case difference of -15.5% from the mean value.
ASTM/DOE Hot Box Round Robin
Authors: Bales E
Published: March 2009

This paper presents the results of inviting the operators of all guarded and calibrated hot boxes in North America to participate in a round robin, an interlaboratory test program according to ASTM E 691, “Conducting an Interlaboratory Test Program to Determine the Precision of a Test Method”, to establish the precision and bias of the corresponding ASTM standard test methods: ASTM C 236, “Steady-State Thermal Performance of Building Assemblies by Means of a Guarded Hot Box”, and C 976, “Thermal Performance of Building Assemblies by Means of a Calibrated Hot Box”. The data and data analysis are reported from twenty-one laboratories that completed a series of tests on 4-inch thick specimens of cellular polystyrene thermal insulation. The data analysis resulted in two recommended statements of precision and bias.

Ninety-five per cent of the time measurements from two different laboratories on the same specimen would differ by up to +/-7.8% at a mean temperature of 75 F for the guarded hot box, and by up to +/-5.6% for the calibrated hot box. Based on guarded hot plate data for the specimen material, the reference value is 15.9 hr-F-ft sq/Btu. The mean of the thermal resistance reported for guarded hot boxes was 15.77 hr-F-ft sq/Btu, which differs by -1.2% from the reference value. The mean of the thermal resistance reported for calibrated hot boxes was 16.32 hr-F-ft sq/Btu, which differs by +2.6% from the reference value.
Thermal Properties of Selected Materials from Steady-State and Transient Tests
Authors: Graves RS , Yarbrough DW , McElroy DL , Fine HA
Published: March 2009

The Unguarded Thin-Heater Apparatus (UTHA, ASTM C 1114) was used to determine the thermal conductivity (k), specific heat (C), and thermal diffusivity (α) of selected building materials from 24 to 50°C. Steady-state and transient measurements yielded data on four types of material: gypsum wall board containing 0, 15, and 30 wt% wax; calcium silicate insulations with densities (ρ) of 307, 444, and 605 kg/m3; three wood products: southern yellow pine flooring (575 kg/m3), Douglas fir plywood (501 kg/m3), and white spruce flooring (452 kg/m3); and two cellular plastic foams: extruded polystyrene (30 kg/m3) blown with HCFC-142b and polyisocyanurate rigid board (30.2 kg/m3) blown with CFC-11. The extruded polystyrene was measured several times after production (25 days, 45 days, 74 days, 131 days, and 227 days). The UTHA is an absolute technique that yields k with an uncertainty of less than ±2% as determined by modeling, by determinate error analyses, and by use of Standard Reference Materials SRM-1450b and SRM-1451.

In the transient mode of operation, a step-change in heat flux was applied to specimens that were initially isothermal or that had a steady, imposed temperature gradient. Analysis of the temperature response of the thin heater for short times predicts a temperature rise that is a linear function of the square-root of time. This behavior was observed for materials with densities above 300 kg/m3 and the slope of this relation provided experimental values for the product k∙ρ∙C. The overall error in determining the product k∙ρ∙C is less than 1%. Values of C were calculated from experimental values of k, ρ, and the product of k∙ρ∙C.

However, for the 30 kg/m3 foams, the thermal mass of the thin heater delayed the onset of the linear temperature rise with the square-root of time. This effect negated the use of the short-time transient analysis for low density materials. A finite difference program that described this observation provided an alternate method to obtain values for the product k∙ρ∙C from the experimental data.
A Comparison of the J-lntegral and CTOD Parameters for Short Crack Specimen Testing
Authors: Sorem WA , Dodds RH , Rolfe ST
Published: March 2009

This study investigates the applicability of the J-integral test procedure to test short crack specimens in the temperature region below the initiation of ductile tearing where JIc cannot be measured. The current J-integral test procedure is restricted to determining the initiation of ductile tearing and requires that no specimen demonstrates brittle cleavage fracture. The JIctest specimen is also limited to crack-depth to specimen-width ratios (a/W) between 0.50 and 0.75. In contrast, the crack tip opening displacement (CTOD) test procedure can be used for testing throughout the entire temperature-toughness transition region from brittle to fully ductile behavior. Also, extensive research is being conducted to extend the CTOD test procedure to the testing of short crack specimens (a/W ratios of approximately 0.15).

The CTOD and J-integral fracture parameters are compared both analytically and experimentally using square (cross-section) three-point bend specimens of A36 steel with a/W ratios of 0.50 (deep crack) and 0.15 (short crack). Three-dimensional elastic-plastic finite element analyses are conducted on both the deep crack and the short crack specimens. The measured J-integral and CTOD results are compared at various levels of linear-elastic and elastic-plastic behavior. Experimental testing is conducted throughout the lower shelf and lower transition regions where stable crack growth does not occur. Very good agreement exists between the analytical and experimental results for both the short crack and deep crack specimens.

Results of this study show that both the J-integral and the CTOD fracture parameters work well for testing in the lower shelf and lower transition regions where stable crack growth does not occur. A linear relationship is shown to exist between J-integral and CTOD throughout these regions for both the short and the deep crack specimens. These observations support the consideration to extend the J-integral test procedure into the temperature region of brittle fracture rather than limiting it to JIc at the initiation of ductile tearing. Also, analyzing short crack three-point bend specimen (a/W < 0.15) records using the load versus load-line displacement (LLD) record has great potential as an experimental technique. The problems of accurately measuring the CMOD of short crack specimens in the laboratory without affecting the crack tip behavior may be eliminated using the J-integral test procedure.
Quantification of Engineering Limits to J Control of Ductile Crack Growth
Authors: Joyce JA
Published: March 2009

The J-integral has been developed as a ductile fracture parameter over the past 15 years and has been applied to an ever-expanding range of applications and materials. Limits originally placed on the application of J by analytical considerations have, in most cases, proven too stringent—and in some cases the analytical limits have even seemed to be inapplicable or irrelevant. This has been particularly true of the omega (ω) criterion introduced by Hutchinson and Paris. Experimental work has seemed to show little correspondence between the limits predicted by this criterion and the experimentally measured size limitations.

Recent experimental work by Joyce et al. has shown that the J-integral is applicable to much larger crack extensions than previously proposed. Using these experiments Joyce and Hackett have proposed an experimental method to define the limit to J-integral controlled crack growth.

This paper now shows that the ω criterion is consistent with the collected data set, except that the limiting value for ω is on the order of one, not the value of 5 to 10 originally proposed. Three simple analyses are presented using the ω criterion to develop proposed limits on J and crack extension that can be used in a predictive manner for fracture analysis.
A Fracture Instability Data Qualification Limit
Authors: Macdonald BD , Oberdick RH , Hiser AL
Published: March 2009

The purpose of this work was to identify a fracture instability data qualification limit. Transition regime fracture data were sorted to disqualify those higher Jmax valued fracture instability data which had exhibited significant prior stable crack extension. Qualified data were identified as having Jmax values below the JIc scatterband. Disqualified data had more than double the average prior stable crack extension of qualified data and had Jmax values in or above the JIc scatterband. The higher Jmax values and significant crack extension of disqualified data appeared to have been associated with a loss of constraint. The data indicated that a specimen size requirement may be needed for elastic-plastic fracture instability data that is different from those for elastic fracture instability or elastic-plastic tearing onset data. However, the value of Jmax relative to the JIc scatterband seems more to the point of identifying data that undergo fracture instability prior to significant crack extension.
Development of Eta Factors in Elastic-Plastic Fracture Testing Using a Load Separation Technique
Authors: Sharobeam MH , Landes JD , Herrera R
Published: March 2009

A method for experimentally determining the eta (η) factor based on separation constants has been recently proposed. This method has two important implications for elastic plastic fracture toughness testing. First, the method can be used to determine the η factors for any new test specimen geometry which might be added to existing test standards. Such specimens as disk compact, arc bend, and arc tension are used in the KIc test standard. They can be added to the J based standards if the specimen calibrations are known, one being the η factor calibration. In this paper a step by step procedure is given describing η factor calibration for an arbitrary specimen geometry based on a series of blunt notched specimens.

The procedure proposed in this paper was then applied to existing blunt notch data for the traditional test specimen geometries, the compact, and single edge notched bend specimens. The results of the study show different values for η from these in the existing standards both in magnitude and trend with a/W. In addition they show a slight material sensitivity. The consequences of having incorrect η factors in the test standards are explored in a sensitivity study. These results are used to evaluate the importance of having correct η factors and recommendations are made.
Experience in Using Direct Current Electric Potential to Monitor Crack Growth in Ductile Metals
Authors: Landow MP , Marschall CW
Published: March 2009

The direct-current electric potential (d-c EP) method is receiving increasing attention as an alternative to the unloading compliance method for monitoring crack initiation and growth during fracture toughness testing of ductile metals. Advantages of the d-c EP method include uninterrupted tests, continuous monitoring of crack extension, ability to accurately measure relatively large amounts of crack growth, and ability to be used at high displacement rates in many materials. The principal shortcoming of the d-c EP method (as with most other methods) is the uncertainty in defining the point of crack initiation in some tests.

This paper describes Battelle's experience in using the d-c EP method to monitor crack initiation and growth in compact (tension) specimens machined from various pipes used in cooling systems of nuclear reactors. Among the materials investigated are carbon steel pipes (base metal and weld metal) and extremely ductile austenitic stainless steel pipes (base metal and weld metal). Discussed in the paper are: (1) estimation of the crack-initiation point from d-c EP data, (2) ability of the d-c EP method to accurately predict large amounts of crack growth in highly ductile metals, (3) modification of the Johnson equation to improve the accuracy of the d-c EP method for large crack growth, and (4) use of the d-c EP method at high displacement rates.
The California Food Safety Initiatives: The Impact on Formulators
Authors: Cummings GL
Published: March 2009

The November, 1990 California ballot contained two initiatives which would impact the agricultural chemical industry. The most noted initiative, Proposition 128 popularly called the Big Green or Hayden/Van de Kamp initiative, addressed several environmentally popular themes, including food safety. The most significant effect on agrichem companies would come from the outright banning of certain chemicals, independent of concentration or risk, in food production. Products would be banned based on toxic active ingredients, metabolites of actives, impurities in actives, degradates of actives, inerts, metabolites of inerts, and impurities in inerts. Production Agriculture had sponsored a second, alternate initiative as a more responsible approach to food safety, Proposition 135. This paper will compare both initiatives, will discuss the initiative strategies and will discuss the potential effects on formulation chemists and inert suppliers.
Starch Matrices for Slow Release of Pesticides
Authors: Shasha BS , McGuire MR
Published: March 2009

Physical entrapment of both biological and chemical pesticides was acheived by encapsulation of active ingredients within starch matrices. Starch is first gelatinized either physically using heat, or chemically using alkali or urea, then pesticide is added followed by the crosslinking of starch. The final product is granular, ready to be used with conventional equipment. Electron microscope photographs reveal the presence of a honeycomb matrix containing the pesticide. Sprayable formulations based on entrapment within starch were also acheived. The sprayable material has a low and stable viscosity and can be used with conventional farm equipment. Upon application it dries to a thin film that does not dissolve in the presence of water.
Starch Encapsulated Herbicide Formulations: Scale-Up and Laboratory Evaluations
Authors: Wing RE , Carr ME , Doane WM , Schreiber MM
Published: March 2009

Non-chemically modified cornstarch effectively encapsulates herbicides. Thousand pound quantities of atrazine, alachlor and metolachlor were prepared by extrusion followed by drying, grinding, and sieving to give the desired size granules. Leaching potential of these formulations was evalulated using soil columns and bioassay techniques. Large quantities of products were sent to cooperators in 10 states for evaluation along with commercial formulations.
The Effect of Carrier Temperature on Pesticide Emulsification or Dispersion Characteristics
Authors: Duckworth CA , Cearnal KS
Published: March 2009

The results of a study determining the effect of carrier temperature on the emulsification or dispersion and redispersion of commercial pesticide formulations are detailed. A series of commercially available emulsifiable concentrate, liquid flowable and dry flowable formulations were evaluated in waters of varying hardness and temperature. This study was extended to several model emulsfiable concentrate systems to determine what adjustments in emulsifier type were required to achieve consistent emulsion performance in water varying in temperature.
Applications of Dynamic Surface Tension to Adjuvants and Emulsion Systems
Authors: Tann RS , Berger PD , Berger CH
Published: March 2009

Dynamic surface tension (DST) measurements were obtained using the Maximum Bubble Pressure Technique for various adjuvant and emulsion systems. These results were compared with traditional test methods for adjuvants and emulsion systems.

The adjuvants were compared to: 1.) Drave's wetting times, 2.) Static surface tension 3.) Static contact angle. The relationships between these properties and dynamic surface tensions at various freguencies were studied. The emulsion system studied contained an anionic surfactant and a nonionic surfactant in a 4 #/gallon pesticide formulation. The resulting emulsions were measured for dynamic surface tension at varying frequencies and compared to traditional emulsion results.

This work demonstrates the application of dynamic surface tension to the study of adjuvants and emulsion stability.
Production, Formulation and Delivery of Beneficial Microbes for Biocontrol of Plant Pathogens
Authors: Fravel DR , Lewis JA
Published: March 2009

Industry in the US is currently capable of large-scale liquid fermentation for production of many common Microbial pest control agents (MPCAs). Large-scale solid and semi-solid fermentation methods have also been developed for MPCAs which do not grow or sporulate well in liquid fermentation. Recent emphasis in formulation research has been in the entrapment of MPCA propagules within a cross-linked matrix of organic polymers such as alginate, polyacrylamide, or carrageenan. Final formulations are uniform granules which are compatible with current agricultural equipment. Most MPCAs survive these formulation processes well and have a shelf-life of several months to a few years. These formulations are relatively inexpensive and permits addition of nutrient bases, pesticides, or other compounds which may confer a selective advantage on the MPCA. Other delivery systems include liquids, dusts, gels, and pastes which are applied to foliage, soil, wounds, and seeds or seedpieces.
Effects of Pump Type on Atomization of Spray Formulations
Authors: Chapple AC , Downer RA , Hall FR
Published: March 2009

The effects on the atomization process with respect to droplet spectra were investigated for three pump systems (a rotary vane pump, a piston pump, and a diaphragm pump) and compared with an air pressure system. The test substances evaluated were water, Ortho X-77 (0.0625% and 0.5%), Windfall and Nalcotrol polymers, and two placebo (blank) insecticides (an emulsifiable concentrate and a wettable powder). All formulations were tested at field rates. All work was done using a TeeJet XR8004VS flat fan nozzle, and a Hardi 1553-12 hollow cone nozzle with a grey swirl. The effect of recirculation of the formulations on the eventual droplet spectra was also investigated. All other spraying parameters were kept constant. Droplet spectra were assessed along the long axis of the spray pattern using an Aerometrics PDPA-100 system, and a Velmex “Unislide” xyz-positioner.

Results indicate that droplet spectra of formulations containing polymers shift significantly with time of recirculation: Dv0.5 decreased by as much as 300 μm for Nalcotrol. The time taken for the Dv0.5 to stabilize depended upon pump type. Water, Ortho X-77, and the two blank formulations remained unaffected by pump type or recirculation. The effect of different mixing regimes prior to atomization was also investigated for Windfall and Nalcotrol.
Evaluating the Field Efficacy of Bacillus thuringiensis Berliner against the Western Spruce Budworm (Lepidoptera:Tortricidae)
Authors: Riley CM , Wiesner CJ , Scott DW , Weatherby J , Downer RG
Published: March 2009

A detailed assessment of spray deposition and efficacy of Dipel 6AF and Thuricide 48LV was carried out as part of the 1988 western spruce budworm control program. An analysis of covariance model was used in an attempt to examine the relationship between deposit density and field efficacy (larval mortality and defoliation) for the two formulations. The model could not be justified and relationships between the variables were investigated using chi-aquare analysis.
Assessing the Performance of Ambient Air Samplers for Volatile Organic Compounds
Authors: Crist HL
Published: March 2009

Performance audit results of two different ambient air monitoring projects for volatile organic compounds (VOCs) are presented. A National Institute of Standards and Technology (NIST) traceable gas cylinder containing several VOCs in dry nitrogen at parts per billion (ppb) concentration levels was used at the field sampling site to evaluate performance of the sampling and analytical systems. Both Tenax cartridges and evacuated stainless steel canisters (6 L) were used to sample the air. Sample media exposed to the audit gas were returned to the laboratory for analysis.

The data indicate that a mean percent bias of 30% or less was achieved for most of the audit compounds sampled by Tenax. The results also show that the canister sampler cannot be adequately evaluated using volatile organics in dry nitrogen because of absorption losses of certain compounds. Several of the less volatile compounds in the audit gas exhibited significantly reduced recovery or were not detected after being sampled by the canister. Recovery of highly volatile compounds in the gas was quantitative. Further investigation showed that the use of humidified audit gas resulted in the quantitative recovery of all the VOCs that were sampled by the canister.
Development of Multicomponent Parts-per-Billion-Level Gas Standards of Volatile Toxic Organic Compounds
Authors: Rhoderick GC , Zielinski WL
Published: March 2009

The demand for stable, low-concentration multicomponent standards of volatile toxic organic compounds for quantifying national and state measurements of ambient air quality and hazardous waste incineration emissions has markedly increased in recent years. In response to this demand, a microgravimetric technique was developed and validated for preparing such standards; these standards ranged in concentration from several parts per million (ppm) down to one part per billion (ppb) and in complexity from one organic up to 17. Studies using the gravimetric procedure to prepare mixtures of different groups of organics, including multicomponent mixtures in the 5 to 20 ppb range, revealed a very low imprecision. This procedure is based on the separate gravimetric introduction of individual organics into an evacuated gas cylinder, followed by the pressurized addition of a precalculated amount of pure nitrogen. Additional studies confirmed the long-term stability of these mixtures. The uncertainty of the concentrations of the individual organics at the 95% confidence level ranged from less than 1% relative at 1 ppm to less than 10% relative at 1 ppb. Over 100 primary gravimetric standards have been developed, validated, and used for certifying the concentrations of a variety of mixtures for monitoring studies.
Analysis of Atmospheric Particulate Samples via Instrumental Neutron Activation Analysis
Authors: Greenberg RR
Published: March 2009

Instrumental neutron activation analysis (INAA) is a powerful analytical technique for the elemental characterization of atmospheric particulate samples. It is a true multielement technique with adequate sensitivity to determine 30 to 40 elements in a sample of atmospheric particulate material. Its nondestructive nature allows sample reanalysis by the same or a different analytical technique. As an example of the applicability of INAA to the study of atmospheric particulate material, a study of the emissions from municipal incinerators is described.
Mutagenic Atmospheric Aerosol Sources Apportioned by Receptor Modeling
Authors: Stevens RK , Lewis CW , Dzubay TG , Baumgardner RE , Zweidinger RB , Highsmith RV , Cupitt LT , Lewtas J , Claxton LD , Currie L , Klouda GA , Zak B
Published: March 2009

During the winter of 1985, the U.S. Environmental Protection Agency (EPA) collected air quality data and samples in residential locations in Albuquerque, New Mexico and Raleigh, North Carolina as part of its Integrated Air Cancer Project (IACP). One of the major objectives of these field monitoring studies was to evaluate new sampling, analysis, and receptor modeling procedures and to apportion the fine particle mass and mutagenic activity of the organic fraction of the fine particles to the appropriate sources.

Samples were collected in the two cities for 12-h periods beginning at 7:00 a.m. and 7:00 p.m. This schedule was followed to aid in resolving the organic and inorganic chemical species emitted from residential wood burning (normally a nighttime activity) and from mobile source emissions (normally a daytime activity). Samples were analyzed for mutagenicity, organic carbon, carbon-14 (14C) content, and inorganic characterizations. Data from these analyses were merged into a single data base and served as input to a multilinear regression (MLR) model that calculates the relative contribution of wood burning and motor vehicle sources to the extractable particle organic matter and mutagenic activity observed in these two cities. The 14C measurements were used to validate the MLR model. Even though the monitoring sites in these cities were both selected and found to be heavily impacted by residential wood burning (83 and 94% of the organic aerosol mass due to wood burning), a proportionately larger percentage of the mutagenicity of the fine particles was attributed to mobile sources (25 and 37%). At both sites the mutagenic potency of the organics extracted from the fine particles were found to be greater (three to five times) for mobile sources when compared with wood smoke extractable organics.
Air Change Measurements of Five Army Buildings in Alaska
Authors: Flanders SN
Published: March 2009

The air change rates of five buildings (four barracks and one vehicle maintenance garage) were measured, using the tracer gas dilution technique. The median air change rate for all zones measured was close to 0.5 air change per hour (ACH). The range of air change rates was between 0.05 and 1.75 ACH. Most of this range was attributable to variation in the effectiveness of the buildings' ventilation systems. Outdoor temperatures were between -15 and -20°C (5 and -4°F). The wind was calm for all but one barracks measurement. The maintenance facility, a large single-zone building, permitted good results from the tracer gas technique. The barracks, multi-zone buildings, varied in the ease with which the tracer gas technique could be applied. The barracks ventilation systems were in operation when air change measurements were made. These systems incorporated air-to-air heat exchangers with intakes and exhausts mounted in rooftop penthouses.