bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Three Experimental Adjuvants on Glyphosate Weed Efficacy
Authors: Roberts JR , Mack RE , Baker TA
Published: April 2008

Many agricultural spray adjuvants utilize one or more organosilicone surfactants in their composition. These materials have been shown to provide biological efficacy enhancement to agrichemicals and/or correct spray application problems. Commercial adjuvant products that utilize organosilicone surfactants are currently formulated only as liquid products.

In recent years, many pesticide products have been introduced as dry formulations. These formulations have provided growers and applicators with the advantages of reduced exposure, improved storage stability and easier package disposal. Until now, the technology necessary to produce dry adjuvants utilizing organosilicone surfactants has been unavailable.

Two formulation technologies now provide the option for developing dry organosilicone spray adjuvant products; a.) dry co-surfactant blends of organosilicone and propylene oxide/ethylene oxide copolymers and b.) organosilicone impregnated on dry carboxylic acid salts. Laboratory evaluations, regarding the surface chemistry properties of these dry organosilicone adjuvants, compare favorably with those from the traditional liquid formulations. The purpose of this research was to determine if glyphosate efficacy enhancement provided by dry organosilicone based adjuvant products, is comparable to control levels of liquid organosilicone based adjuvant with glyphosate and to evaluate the impact of dry surfactant formulation variables. The field efficacy experiments were conducted at eight locations in the northern and southern regions of the United States, to evaluate glyphosate activity on various annual and perennial weed species. The experimental adjuvants were tank mixed with a glyphosate formulation that did not contain surfactant. A 731 mL/ha rate of glyphosate was applied at seven of the sites, with one location having had al462 mL/ha rate applied.

HM9208-A and HM9507 (dry formulations of organosilicone surfactants), were applied 453.6 grams/379 liters of spray solution. HM9220 (a liquid formulation of organosilicone surfactant), was applied at 0.125% v/v concentration. All treatments were applied at 94 L/ha spray volume. Applications to quackgrass, perennial ryegrass, rhizome johnsongrass, alfalfa and annual fleabane resulted in greater levels of weed control due to the addition of HM9208-A versus HM9507 or HM9220. Applications to Timothygrass resulted in equivalent control levels among the three adjuvants. At a site in Mississippi, glyphosate plus HM9208-A provided better control of goosegrass and southwestern cupgrass when compared to the addition of HM9507. Control levels were equivalent on these two weed species with either HM9208-A or HM9220.
Optimum Surfactant HLB Value for Nicosulfuron Is Salt Dependent
Authors: Nalewaja JD , Matysiak R , Woznica Z
Published: April 2008

Experiments were conducted to determine nicosulfuron {2-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-N,N-dimethyl-3-pyridinecarboxamide} phytotoxicity to large crabgrass (Digitaria sanguinalis L.) as influenced by surfactant HLB, spray volume, pH, and carrier solution salts. Nicosulfuron phytotoxicity to crabgrass was greater when applied in 240 than 80 L/ha in a pH 4 spray carrier, regardless of surfactant. However at pH 9, 80 L/ha spray volume also was effective when most surfactants had a HLB value between 12 and 17. Surfactant chemistry determined the effect of sodium bicarbonate and ammonium nitrate on nicosulfuron efficacy. The optimum HLB for a surfactant with nicosulfuron was lowered when the spray carriercontained ammonium nitrate. Ammonium nitrate enhanced or reduced nicosulfuron phytotoxicity depending on the HLB and chemistry of the accompanying surfactant. Sodium bicarbonate antagonized nicosulfuron phytotoxicity more when applied with low (12 to 13) than high (16 to 17) HLB surfactants. The data demonstrate that the most efficacious surfactant for nicosulfuron depends upon spray volume, pH, and carrier salt.
The Physical Chemistry of WDGs: Porosity and Surfactant Dissolution as a Function of Dispersant Molecular Weight
Authors: Delli Colli HT , Doering IW
Published: April 2008

The speed and completeness of the disintegration of water-dispersible granules depend upon several factors. Two of the most important are the porosity of the individual granules and the rate of dissolution of the surfactant package within the formulation.

The present work represents a small piece of a larger overall effort designed to explore the physicochemical aspects of WDG development. An objective of the larger effort is the enablement of the formulation chemist to identify key compositional and production related parameters for WDGs early enough in the development process to significantly shorten it.
Novel High Performance Water-Soluble Antifoam Based on Perfluoroalkylphosphinic and Perfluoroalkylphosphonic Acids in Crop Protection
Authors: Dookhith MT
Published: April 2008

Surface active agents are used to formulate active ingredients for crop protection and are used in either liquid or solid form. The trend is to also incorporate wetting agents in the formulation in order to achieve bio-efficacy enhancement thus lowering the surface tension of the spray solution, resulting in uniform wetting and spreading when in contact with leaf surfaces. Often these wetting agents will produce a high level of foaming in the spray tank. This is undesirable due to the fact that an overflowing spray tank can cause a worker exposure problem.

Foam is extremely complex consisting of polydisperse gas bubbles separated by draining films. These films exhibit complicated hydrodynamics involving the distinct rheology of air-liquid surfaces and, for thin films, colloidal interaction forces. The nature of the foam film collapse processes that are intrinsic to foam are still not well understood. Antifoams are generally hydrophobic, finely divided insoluble materials and, therefore, their presence further complicates the complexities associated with foam. In the case of perfluorinated acids, the agent is solubilized in the foam film and drastically reduces the surface tension between the air-liquid interfaces. Theories of the antifoam mechanism appear to fall into two broad categories: those requiring the antifoam to be surface active at the air-liquid surfaces of the foaming liquid and those that do not.

A multiplicity of antifoams is known; however, these products are unstable under conditions such as high shear temperatures, long-term storage, acid, alkaline and highly ionic medium. Chemistry based on a perfluorinated acid has shown to overcome the previously mentioned issues. In addition, this new compound has the great advantage of being water soluble.

This new compound (Figure 1 ) is highly surface active with an extremely low surface tension of 19 mN/m measured on a 0.1% aqueous solution. The antifoaming behavior is related to the effect of the surface tension in the foam films leading to film rupture.

This paper explains the advantages of perfluoroalkylphosphinic and perfluoroalkylphosphonic acids as a high performance antifoam versus an organo-silicone antifoam.
The Evolution of Base Oil Technology
Authors: Kramer DC , Lok BK , Krug RR
Published: April 2008

From its humble beginnings over 3000 years ago, lubrication technology has seen many phases of evolution. As it continues to evolve at an ever-increasing rate, base oil performance is making a larger contribution to finished lubricant performance. Turbine oils are perhaps the most dramatic example because they typically contain over 99% base oil.

Early lubrication began with animal fats and oils and slowly evolved to petroleum-based oils. Many generations of refining processes have since improved on Mother Nature. Early processes such as acid treating and solvent extraction improved the quality of base oils by removing some or most of the worst molecules from the oil. Later processes like hydrotreating, catalytic hydrocracking, catalytic dewaxing, and modern wax hydroisomerization transformed feed molecules into molecules with improved lubricating qualities.

Modern wax hydroisomerization, in particular, makes base oils with very low impurities and typically water-white appearance. Now, about one third of all base oils manufactured in North America are of such high quality.

Looking to the future, the trend is toward even higher base oil purity, higher viscosity index (V.I.), lower volatility, and longer life. The distinction between heavily processed mineral oils and traditional “synthetic” oils will continue to blur.

The evolution and future of base oil technology will be discussed in more detail in this paper.
Limitations of Bench Testing for Gear Lubricants
Authors: Hoehn B-R , Michaelis K , Doleschel A
Published: April 2008

Base oil type, viscosity, and additive packages of gear lubricants influence gear failures as wear, scuffing, micropitting and pitting as well as power loss and efficiency. Numerous test methods have been developed to quantify these influences.

Different test equipment like a gear test rig, a twin disk machine and the Shell four ball tester are shown and discussed. Results of lubricants in these bench tests on scuffing, pitting and friction behaviour are shown and compared to each other and to gear performance.

It can be summarized that poor correlation has to be stated for the bench tests with 100% sliding rate. For the twin disk simulation poor correlation was found for scuffing results, good relative but poor absolute correlation for pitting results and both good relative and absolute correlation for the frictional behavior. From these investigations it has to be concluded that bench test results applied to gears have to be regarded very critically and can only be interpreted correctly with excellent experimental background and experience.
Testing Extreme Pressure and Anti-Wear Performance of Crankcase and Gearbox Lubricants
Authors: Alliston-Greiner AF , Plint AG , Plint MA
Published: April 2008

When designing a bench test to model wear in lubricated contacts associated with engine and gearbox applications, considerations of scale are important. It is hazardous simply to attempt to define the “real life” conditions (load, speed, temperature, etc.) and glibly apply them to test pieces on a bench test machine. If large amounts of energy are being dissipated in small test specimens with supporting structures that do not allow the heat to escape, then it is clear that the specimens will become very hot. The bulk temperature may exceed what is experienced in practice, producing transitions in wear or frictional response. This paper outlines the relationship of wear and failure to energy dissipation in terms of two global parameters, Matveesky's Friction Power Intensity and Plint's Energy Pulse, and applies these to previously published data. It then shows how these can be used in the design of appropriately scaled, simple bench test procedures for the evaluation of lubricants for two practical EHD lubricated contacts (gears and cam/follower).
Tribological Testing of Lubricants and Materials for the System “Piston Ring/Cylinder Liner” Outside of Engines
Authors: Woydt M , Kelling N
Published: April 2008

The test procedure for characterizing the tribological behavior of lubricants and materials for the system “piston ring/cylinder liner” outside of engines is now operational and validated. The test parameters presented in this paper (FN= 50 N; v= 0,3 m/s, s= 24 km) may act only as an indicator and should be adopted to the tasks regarded. It allows the check prior expensive engine testing, if a tribo-material, tribo-couple or new lubricant will reach a satisfactory engine performance.

The introduction of piston ring segments and cylinder liner as specimen into the test rig as well as the volumetric wear determined by means of stylus profilometry represented a big step forward in order to increase the transferability of “tribo-tests” to engine tests on an acceptable level.
Bench Test Determinations of Wear Modes to Classify Morphological Attributes of Wear Debris
Authors: Roylance BJ , Sperring TP , Barraclough TG
Published: April 2008

Wear particles represent a crucial source of additional information in performing fundamental wear studies. It has also found important application in monitoring the deterioration of critical components in industrial machinery due to wear, notably in militarily-related machinery functions such as engines and gear transmission units. In this paper, a summary account is given of the way in which specific test machines have recently been utilized to produce wear debris under controlled test conditions. In particular, the morphological features of wear debris are described in relation to wear characteristics obtained from using three test machines: four-ball, pin-on-disc, and gear test machine, respectively. The results of subsequent microscope analysis and classification of the debris morphology are described in relation to the corresponding wear modes experienced in the test. The implications for application of a new software-based, wear debris classifier are reviewed and discussed in relation to present-day methods employed in the maintenance of military engines and gear transmission systems.
Corrosive Wear Testing of Metals in Seawater
Authors: Kawazoe T , Ura A
Published: April 2008

The objective of this study is to evaluate the corrosive wear resistance and to clarify the damage behavior of materials used for sliding parts in seawater. Sliding wear tests of six different metals including carbon steel, stainless steel and copper base alloys rubbed against A12O3 and a bearing steel were carried out in 3% NaCl solution using a reciprocating ball-on-disk test rig equipped with an electrochemical potentiostat. The obtained results indicate that the corrosive wear resistance should be evaluated by synthetically considering many factors: electrochemical potentials, material properties, and corrosion characteristics of the contacting materials, including corrosive products.
Simulation of Tribological Performance of Coatings for Automotive Piston Ring and Timing Chain in Bench Testing
Authors: Gao C , Gitis N , Nguyen N , Vinogradov M
Published: April 2008

Piston rings with three different coatings were tested on a lubricated cylinder liner for friction force, wear depth, electric contact resistance (ECR) and acoustic emission (AE), using Micro-Tribometer model UMT. UMT was also used to test four types of coatings on timing chain linkage pins to evaluate their scratch resistance with a wedge-shaped micro-blade made of tungsten carbide. Scratch resistance measurements with a diamond stylus of 0.5 μm radius were much less distinctive for the four coatings, as compared to those with the micro-blade. It was found that when the micro-blade broke through the coating on the linkage pins, the AE signal changed more rapidly than the friction force. The friction force could not distinguish tribology performance between Coating 1 and Coating 2, whereas the AE easily differentiated the two coatings. In the testing of piston-ring coatings, it was found that ECR increased with running time during the first half hour or so. It reflected the lubricant buildup at the interface, since the lubricant introduces a much higher electrical resistance. The AE signal was found not always correlated with friction forces, since mechanical interactions contributing to AE are not only along the factional direction. Good correlation was found for wear depth measured in-situ using UMT and post-test using a Tencor profilometer. Testing repeatability was demonstrated.
Tribology Testing for Load Carrying Capacity of Aircraft Propulsion System Lubricating Oils
Authors: Wedeven LD , Hille E
Published: April 2008

A tribology testing capability has been developed to provide a closer link between bench testing and performance in component hardware. The new test capability enables simulation of lubrication and failure mechanisms that control the life and durability of lubricated contacts in machine hardware. The key feature associated with simulation is the independent control of entraining velocity and sliding velocity. The Wedeven Associates, Inc. test machines (WAM) control the motions and forces of a single contact in 3-dimensional space. The machine software links the operator to the machine with tribologically meaningful parameters. The value of this approach is shown by test protocols developed for the evaluation of aircraft propulsion oils. The test protocol simulates the Ryder Gear Test Method, which is based on a scuffing performance criterion. The inclusion of traction (friction) measurements is found to reflect wear and a superficial form of scuffing (micro-scuffing). The test method illustrates the performance of U.S. Navy oils formulated for corrosion inhibition (CI). In addition to additive chemistry, the results show the chemical contribution of the base stock with respect to wear and scuffing resistance.
Master Curve Evaluation of Irradiated Russian VVER Type Reactor Pressure Vessel Steels
Authors: Viehrig H-W , Boehmert J , Dzugan J , Richter H
Published: April 2008

Results of a joint German/Russian irradiation program performed on the prototype pressurized water reactor VVER-2 of the Rheinsberg nuclear power plant (Germany) are summarized. The experiment comprises Charpy V-notch (CVN), precracked Charpy size (SENB) and compact tension (CT) specimens made of different heats of Russian VVER type reactor pressure vessel (RPV) base and weld metals. Reference temperatures, T0, were evaluated according to the Master Curve (MC) concept using the multi temperature method. Neutron irradiation induced ductile-to-brittle transition temperature (DBTT) shifts determined on the basis of CVN and SENB tests are compared. On the base of the DBTT the neutron embrittlement sensitivity and the annealing behavior of tested RPV steels are evaluated. Different heats of the same VVER-RPV steel exhibit different neutron induced embrittlement and annealing behavior. The determined CVN transition temperatures correlates to the T0 temperatures evaluated by the MC concept.
Behavior of Different Austenitic Stainless Steels, Conventional, Reduced Activation (RA) and ODS Chromium-Rich Ferritic-Martensitic Steels Under Neutron Irradiation at 325°C in PWR Environment
Authors: Brachet J-C , Averty X , Lamagnère P , Alamo A , Rozenblum F , Raquet O , Bertin J-L
Published: April 2008

The main objective of this paper is to summarize CEA data recently obtained on different kinds of steels irradiated at 325°C in the Osiris experimental reactor in a typical PWR environment, that is, pressurized water — P=155 bars — with controlled PWR type chemistry. The different steels studied can be classified in four groups: 304/316 type austenitic stainless steels, conventional 9–12%Cr(Mo,V,Nb) and reduced activation 7.5–11%Cr(W,V,Ta) martensitic steels, and two ferritic-martensitic alloys strengthened by oxide dispersion (ODS). Some of those steels have been included with different initial metallurgical conditions, that is, (1) for austenitic steels : solution annealed and cold-worked structures; (2) for martensitic steels : tempered, cold-worked and as-quenched martensitic structures. This experimental irradiation, named “Alexandre”, has been carried out in the Osiris experimental reactor (under a mixed fast/thermal neutron flux) for different neutron fluence levels with a maximum irradiation damage of ∼9dpa. The main results obtained are discussed, with a special emphasis on the chemical composition and initial metallurgical condition effects on the tensile and uniform corrosion properties of both conventional and reduced activation chromium-rich martensitic steels.
Microstructural Alteration of Structural Alloys by Low Temperature Irradiation with High Energy Protons and Spallation Neutrons
Authors: Sencer BH , Bond GM , Garner FA , Maloy SA , Sommer WF , James MR
Published: April 2008

Several candidate alloys (nickel-based Alloy 718, iron-based 316 L and 304 L stainless steels) have been exposed to mixed proton-neutron particle fluxes and spectra at the Los Alamos Neutron Science Center (LANSCE), with the radiation conditions similar to those expected in the proposed Accelerator Production of Tritium (APT) facility. All alloys developed a high density of small black-spot damage and larger Frank loops, even at the lowest dose examined, producing rapid hardening and concurrent loss of ductility. The radiation-induced evolution of both microstructure and mechanical properties in the 300-series stainless steels is relatively simple, whereas that in Alloy 718 is rather more complex,. Superlattice spots corresponding to the age-hardening precipitate phases γ ′ and γ ″ are lost from the diffraction patterns for Alloy 718 by only 0.6 dpa, the lowest proton/neutron-induced dose level achieved in this experiment. Examination of neutron-irradiated samples to doses of only ∼0.1 dpa showed that precipitates are faintly visible in diffraction patterns but are rapidly becoming invisible. It is proposed that the γ ′ and γ ″ first become disordered (by <0.6 dpa), but remain as solute-rich aggregates that still contribute to the hardness at relatively low dpa levels, and then are gradually dispersed at higher doses.

The two 300-series stainless steels (SS) appear to exhibit essentially identical evolution both in their microstructure and mechanical properties. In the 300-series stainless steels, there is an initial strong decrease in uniform elongation at very low dose levels, followed by a second, rather abrupt contribution to ductility loss at higher doses (>3dpa) that is not accompanied by any observed new or enhanced microstructural development. This may be a manifestation of gas-induced loss of ductility resulting from large levels of hydrogen and helium generated by irradiation in these alloys. Although the retained gas levels approached ∼1 at% at the highest exposure levels, no discernible cavities were observed in any of the alloys.

With one significant exception, all observed features of radiation-affected properties can be explained in terms of the observed developments in irradiated but undeformed microstructure. Explanation of the remaining feature will require observation of post-deformation microstructure.
Microstructural Evolution of Reduced Activation and Conventional Martensitic Steels after Thermal Aging and Neutron Irradiation
Authors: Mathon M-H , de Carlan Y , Geoffroy G , Averty X , de Novion C-H , Alamo A
Published: April 2008

Small-Angle Neutron Scattering (SANS) allows characterization, in a non-destructive way, of the heterogeneities (precipitates, pores, cavities,…) ranging in size between 1 and 100 nm. The SANS technique has been used in order to study the microstructural evolution of martensitic steels under neutron irradiation at 325 °C up to a dose of 0.9 dpa, and after thermal aging between 250°C and 550°C up to 22 000 hours. The investigated materials were Fe-7.5/1 1Cr WVTa Reduced Activation and Fe-9/12Cr MoWV conventional martensitic steels. SANS experiments were coupled with Transmission Electron Microscopy (TEM) observations. The structural information obtained by SANS and TEM is compared with the evolution of mechanical properties. Three main results have been obtained: (1) above 8.8 at.% Cr in solid solution, the ferritic matrix is unstable at an aging temperature of 400°C and separates into a Cr-depleted α and a Cr-rich α′ b.c.c. phase; (2) moreover, a strong radiation-accelerated or induced α′precipitation is observed in alloys irradiated at 325°C; (3) the precipitation of Laves phase Fe2(Mo,W) is strongly dependent on the Mo and W content in the alloys.
Effect of Nickel on Irradiation Hardening and Microstructure Evolution of Proton Irradiated Fe-Cu Alloys
Authors: Shibamoto H , Kitao T , Matsui H , Hasegawa M , Yamaguchi S , Kimura A
Published: April 2008

Hardness measurements and microstructure examinations of Fe(-C)-Cu-Ni model alloys were performed following 1 MeV proton irradiation below 80°C. Microstructural examinations by transmission electron microscope (TEM) were carried out by means of a cross section method. A band of damage structures, parallel to the irradiated surface, was observed at a depth of 6.5 μ m in agreement with calculation based on the TRIM code. TEM observation revealed that the band consisted of high density of small black spots, which were considered to be interstitial-type dislocation loops. The amount of irradiation hardening increased with increase in copper concentration. An addition of 0.6wt%Ni to Fe-Cu alloys further increased the hardening, although the effect was reduced with increasing copper concentration. Irradiation hardening of pure iron was also significantly increased by the addition of nickel. The size and number density of the spot-like structures in Fe-Cu alloys decreased and increased, respectively, with addition of nickel. Three recovery stages were found in Fe-Cu-Ni alloys during post-irradiation isochronal annealing to 675°C: the stages are at around 150°C, 400°C and 600°C. The first stage was only observed in nickel-containing alloys, while the third stage was only observed in copper-containing alloys. After annealing to 375°C, the density of spot-like structures decreased in Fe-Cu-Ni alloy but increased in Fe-Cu alloy, while for both the size of spots increased.
Pesticide Spray Droplet Adhesion Modeling
Authors: Forster WA , Kimberley MO , Zabkiewicz JA
Published: April 2008

Spray droplet adhesion is a consequence of dynamic interactions of formulants within the spray droplet during flight and on impact, physical properties of the droplet (size and velocity), leaf surface morphology and leaf orientation. The objective of this study was to improve on a universal adhesion model incorporating the above factors. The previous spray droplet adhesion model has been extended to include droplet size (ranging from 180 μm to 1000 μm) and droplet velocity (0.63 ms-1 to 2.82 ms-1 at impact), and made more robust by increasing the number of formulations (dynamic surface tension of droplets at impact range from 20.7 to 72 mN m-1), the types of leaf surfaces (20% acetone contact angles on the leaf surfaces range from 61° to 124°), and the number of droplet impact angles (leaf angles from horizontal to 67.5°). In this study, contact angles using 20% acetone:water accounted for 95% of the differences between the leaf surfaces studied compared to 76% previously observed with water only. The present universal model explains 74% of the deviance. The current model's capabilities and limitations are discussed in relation to the physical parameters measured and observed.
Characterization of Fretting Fatigue Process Volume Using Finite Element Analysis
Authors: Swalla DR , Neu RW
Published: April 2008

Fretting fatigue damage is characterized by the nucleation of cracks very early in the life of a component along a critical plane at an oblique angle to the contact surface. The number of cycles to fretting fatigue crack nucleation as well as the orientation of the initial crack critical plane is strongly influenced by the large stress and strain gradients that occur within a small volume near the fretting contact. Therefore, it is necessary to average the stresses and strains along a critical plane within a fretting fatigue process volume (FFPV) to obtain more reliable crack nucleation predictions. An approach for computing damage in a FFPV using finite element analysis is presented. The life and crack angle prediction is consistent with experimental observations of fretting fatigue tests on PH 13-8 Mo stainless steel. This averaging method allows for the introduction of a length scale for crack nucleation prediction.
Fretting Fatigue Characteristics of Titanium Alloy Ti-6Al-4V in Ultra High Cycle Regime
Authors: Shirai S , Kumuthini K , Mutoh Y , Nagata K
Published: April 2008

In the present study, fretting fatigue behavior of a Ti-6Al-4V alloy under high stress ratios in the ultra high cycle regime (up to 109 cycles) has been investigated. The slope of S-N curve decreased with increasing stress ratio. The slope was steeper in short fatigue life region and became flatter in longer life region. The test results under various stress ratios followed the modified Goodman diagram for both the fatigue strengths defined at 107 cycles and 108 cycles. The so-called non-propagating cracks, which were often observed in steels and aluminum alloys, could not be found in the run-out specimens tested up to 107 cycles. In the further loading cycles up to 109 cycles at the same stress amplitude, no crack initiation and propagation could be observed, which indicated that the conventional fretting fatigue strength defined 107 cycles was still effective at least up to 109 cycles. Different behavior between the titanium alloy used and the other materials mainly results from the different crack initiation behavior.
Development of Tentative Guidelines for the Selection of Aggregate Gradations for Hot-Mix Asphalt
Authors: Birgisson B , Ruth BE
Published: April 2008

Aggregate gradations for quality hot-mix asphalt (HMA) should be selected to minimize sensitivity to the variability in asphalt content and gradation during production. In this paper, Job Mix Formulas (JMF) of known performance were obtained from various agencies. These JMF were analyzed in an effort to establish relationships, criteria, and guidelines to facilitate the identification of high quality aggregate gradations, based on a demonstrated record of good in-service pavement performance on fairly high traffic highways.

The results from this study provide a tentative approach for the selection of aggregate gradations for HMA. The coarse aggregate gradations for these asphalt mixtures were defined by a regression power law equation according to the effective maximum size of the aggregate blend. Similar analyses of fine aggregate gradations produced groupings according to the maximum size aggregate and percent passing the 4.75 mm sieve.
Overview of ASTM MNL 40, Moisture Analysis and Condensation Control in Building Envelopes
Authors: Trechsel HR
Published: April 2008

Following up on ASTM MNL 18, Moisture Control in Buildings, ASTM Committees C16 and E06 now co-sponsor ASTM MNL 40, Moisture Analysis in Buildings. MNL 40 expands the chapters on Modeling and on Design Tools and adds to the chapters on Weather Data and Materials Data of MNL 18, published in 1994.

The purpose of the new manual is to provide an overview of the current state of moisture analysis in buildings, to encourage the use of moisture analysis by building designers and practitioners, and to provide the necessary technical background for conducting moisture analysis as an integral part of building design. The manual consists of ten chapters written by individual experts. Included are an extensive Glossary of terms used in moisture analysis and a moisture primer addressing the reader with no or with only limited understanding of hygrothermal mechanisms. Other chapters discuss weather and material data and failure criteria. The manual continues with two overviews of analysis methods, a chapter on manual methods and chapters on the models MOIST and WUFI ORNL/IBP. The manual concludes with a Look to the Future. Enclosed with the manual are CD-ROM disks with the programs for MOIST and WUFI ORNL/IBP, including the necessary owners manuals, and with two conversion programs for properties of air.
Direct Tension and Fracture Toughness Testing Using the Lateral Force Capabilities of a Nanomechanical Test System
Authors: LaVan DA , Jackson K , McKenzie B , Glass SJ , Friedmann TA , Sullivan JP , Buchheit TE
Published: April 2008

The behavior of MEMS devices is limited by the strength of critical features such as thin ligaments, oxide cuts joining layers, pin joints, and hinges. Polysilicon devices fabricated at Sandia's Microelectronic Development Laboratory as well as single layer amorphous diamond MEMS structures have been successfully tested to investigate these features. A series of measurements was performed on 2.5 μm thick, 1.8 μm wide samples with gage lengths of 15 to 1000 μm. Conventional samples, notched samples, as well as samples that include the critical features of standard components in the test section were tested.
Fracture Behavior of Micro-Sized Specimens with Fatigue Pre-Crack Prepared from a Ni-P Amorphous Alloy Thin Film
Authors: Takashima K , Shimojo M , Higo Y , Swain MV
Published: April 2008

Fracture toughness tests have been performed for an electroless deposited Ni-P amorphous alloy thin film with different crack growth directions, which are perpendicular and parallel to the deposition growth direction. Cantilever beam type specimens with dimensions of 10 by 10 by 50 μm3 were prepared from a Ni-P amorphous thin film, and notches with different direction were introduced by focused ion beam machining. Fatigue pre-cracks were introduced ahead of the notches. Both introduction of fatigue pre-cracks and fracture tests were performed using a newly developed mechanical testing machine for micro-sized specimens. Fracture behavior is different between the two types of specimens. KIC values were not obtained as the criteria of plane strain requirements were not satisfied for this size of the specimen, so that the provisional fracture toughness KQ values were obtained. The KQ value of the specimen with crack propagation direction being parallel to the deposition growth direction was 7.3 MPa m1/2, while that with crack propagation direction being perpendicular to the deposition growth direction was 4.2 MPa m1/2. These results suggest that the electroless deposited amorphous alloy thin film has anisotropic mechanical properties.
Characterization of the Young's Modulus of CMOS Thin Films
Authors: Hossain N , Ju JW , Warneke B , Pister KSJ
Published: April 2008

We have developed a technique to determine the local Young's moduli of the thin films within a composite stack of CMOS films, without accessing the individual layers during processing. By fabricating cantilevers of various combinations of field oxide, polysilicon 1, gate oxide, polysilicon 2, oxide 1, metal 1, oxide 2, metal 2, and overglass, measuring the thicknesses of each layer in a cross-section SEM, and deflecting the cantilevers with a Tencor Alpha Step profilometer, we were able to determine the Young's modulus for each film from elastic beam theory. The values we determined for the field oxide, polysilicon, and metal layers were in close agreement with published data on similar but isolated pure films. Values were also determined for the proprietary interlayer dielectrics and passivation overglass layers whose compositions are unknown and thus not available in the literature. These results are of use to MEMS designers utilizing CMOS processes since they do not have control over the mechanical properties of the films in the process nor are they able to directly measure them.
Tensile Tests of Various Thin Films
Authors: Sharpe WN , Jackson KM , Coles G , Eby MA , Edwards RL
Published: April 2008

Test methods for two types of thin-film tensile specimens have been developed in earlier works, and these are reviewed as background for new applications. Two kinds of specimens are tested. The first is 600 μm wide and suspended across a support frame, and the second is 6 to 50 μm wide and fixed to the silicon substrate at one end. Test systems incorporating force, strain, and displacement measurement are used, and Young's modulus can be obtained by three methods, which yield equivalent results.

Tensile stress-strain curves of polysilicon have been recorded over the temperature range 30 to 250°C. The modulus decreases at a rate of 0.043 GPa/°C, and the strength increases slightly, although the scatter of the data is large in both cases. Polysilicon specimens produced by three vendors show essentially the same Young's modulus, but the fracture strengths vary by almost a factor of two.

The first tensile tests of silicon nitride film are reported. The specimens are 0.5 μm thick, 600 μm wide, and 4 mm long in the gage section. Young's modulus is measured as 255 ± 2.6 GPa, Poisson's ratio is 0.22 ± 0.02, and the fracture strength is 6.42 ±1.11 GPa.
Determining the Strength of Brittle Thin Films for MEMS
Authors: Johnson GC , Jones PT , Wu M-T , Honda T
Published: April 2008

Design of micro-electro-mechanical systems (MEMS) requires characterization of the materials involved. However, because the structural dimensions found in MEMS are so small, measurement of even the most basic properties is challenging. This work focuses on techniques for determining the strength of MEMS materials. Several approaches are presented and compared. Results for the failure strength of a common brittle MEMS material are discussed. It is shown that a probabilistic approach must be used to understand the results, and that the apparent strength of this material depends considerably on the mode of deformation (tension vs. bending). The probabilistic approach suggests a dependence in strength on both specimen size and deformation mode. Issues such as load alignment and difficulty in determining specimen geometry are also considered
Thermomechanical Characterization of Nickel-Titanium Copper Shape Memory Alloy Films
Authors: Seward KP , Ramsey PB , Krulevitch P
Published: April 2008

In an effort to develop a more extensive model for the thermomechanical behavior of shape memory alloy (SMA) films, a novel characterization method has been developed. This automated test has been tailored to characterize films for use in micro-electromechanical system (MEMS) actuators. The shape memory effect in NiTiCu is seen in the solid-state phase transformation from an easily deformable low-temperature state to a “shape remembering” high-temperature state. The accurate determination of engineering properties for these films necessitates measurements of both stress and strain in microfabricated test structures over the full range of desired deformation. Our various experimental methods (uniaxial tensile tests, bimorph curvature tests, and diaphragm bulge tests) provide recoverable stress and strain data and the stress-strain relations for these films. Tests were performed over a range of temperatures by resistive heating or ambient heating. These measurements provide the results necessary for developing active SMA structural film design models
Deformation and Stability of Gold/Polysilicon Layered MEMS Plate Structures Subjected to Thermal Loading
Authors: Dunn ML , Zhang Y , Bright VM
Published: April 2008

We study the deformation and stability of a series of gold/polysilicon MEMS plate structures fabricated by the MUMPS surface micromachining process and subjected to uniform temperature changes. We measured, using an interferometric microscope, full-field deformed shapes of a series of circular gold (0.5 μm thick)/polysilicon (1.5 μm thick) plate structures of diameters ranging from D = 150 to 300 μm. From these measurements we determined the pointwise and average curvature of the deformed plates. Although the curvature generally varies with position, the deformation response of the plates can be broadly characterized in terms of the average curvature as a function of temperature change. In terms of this, three regimes were observed: i) linear thermoelastic response independent of plate size, ii) geometrically nonlinear thermoelastic response that depends on plate size, and iii) bifurcations in the curvature-temperature response that also depend on plate size. We modeled the deformation response both analytically and with the finite element method. Good qualitative and quantitative agreement was obtained between predictions and measurements in all three deformation regimes, although the details of bifurcation are less accurately predicted than the linear and nonlinear response. This is attributed to their strong sensitivity to slight imperfections. Good agreement was also obtained between measurements and predictions of the spatial nonuniformity of the curvature across the plate.
AMPHITOX: A Customized Set of Toxicity Tests Employing Amphibian Embryos
Authors: Herkovits J , Pérez-Coll CS
Published: April 2008

Based on a large number of toxicity studies of single chemicals and complex mixtures, a set of four toxicity tests utilizing amphibian embryos (AMPHITOX) was developed (Herkovits and Pérez-Coll 1999). In this contribution, the versatility of AMPHITOX for the evaluation of the toxicity in 36 environmental samples is reported. AMPHITOX can be customized to acute (AMPHIACUT), short-term chronic (AMPHISHORT), and chronic (AMPHICHRO) exposure periods. By plotting the LC10 (or NOEC), LC50 and LC90 (or LC100), the toxicity profile (TOP) curves from 24 hr to 14 days of exposure can be obtained allowing the visualization of concentration- and time-exposure thresholds, as well as the range of concentrations which exerts adverse effects in each case. By employing the early-life-stage test (AMPHIEMB) it is also possible to evaluate malformations. The environmental samples studied were obtained from surface and ground water, leaches, industrial effluents and soils. Data from acute, short-term chronic and chronic tests, were expressed as LC50-96 h, NOEC 168 h (7 days) and NOEC 336 h (14 days). The maximal value for acute toxicity was 0.5 % V/V (in a leach), while the lower toxicity was 85 % V/V corresponding to the NOEC/14 days for a leach sample. In 6 samples (4 provided from reference places) no toxicity was detected. By applying the AMPHIEMB test in a water sample providing from Gutierrez stream in Lujan, Buenos Aires Province, 100 % lethality with concentrations over 50 % within 7 days of exposure was obtained and the surviving embryos exhibited reduced body size, delayed development and malformations. Malformations including microcephaly, abnormally developed tail and severe flexures, were proportional to the concentration of the sample. The results point to the possibility of evaluating the toxicity of a wide diversity of environmental samples. This may be accomplished by selecting the most appropriate AMPHITOX test according to the toxicity of the sample and the end point of major relevance. Ultimately amphibian embryos can be used in toxicity studies as indicators of environmental quality for wildlife protection purposes.
Application of Latex Emulsion Polymers in Seed Coating Technology
Authors: Herbert RM
Published: April 2008

Choice and concentration of latex emulsion polymer is critical to the development of a seed coating which demonstrates excellent properties of abrasion resistance and seed flowability without adversely affecting seed germination and ultimate crop yield.

With low use rate insecticides and fungicides as seed coatings it is important to form a continuous coating over the seed surface by optimum addition of polymer and/or solid diluent. Use of the experimental design associated with blending allows the formulator to identify this precise composition and provides a framework for comparing the performance of alternative emulsion polymers and diluent solids.

Built-in seed coating formulations of low use rate insecticides and fungicides, developed by the addition of 5–20 %w/w emulsion polymer, demonstrate comparable abrasion resistance to the suspension concentrate itself.
Effect of the Lignin Component Size and Proportioning on the Performance of Heterogeneous Sulfonated Lignin Dispersants
Authors: Winowiski T , Lebo S , Stoviak R , Gustafsson J
Published: April 2008

Kraft lignin (KL) was ultrafiltered (UF) to produce a low molecular weight (Mw) fraction with Mw of 4000 daltons (LMWKL) and a higher Mw fraction with Mw of 40 000 daltons (HMWKL). The UF fractions were combined with a high Mw sulfite lignin (SL) such that LMWKL or HMWKL comprised 15, 30, or 45% of total solids. These combinations were pressure cooked for 2 hours at 150°C and the resulting products tested as dispersants. All combinations showed significant improvement in suspensibility of 85% copper oxychloride (COC) wettable powder (WP) in extra-hard water versus cooked sulfite lignin (CSL). There were no differences associated with type or level of the added UF material. Milling viscosity of a sulfur suspension concentrate (SC) was reduced by all combination products versus CSL. This response was greater for LMWKL cooks (LC) and increased directly with increasing levels of either UF fraction. Suspensibility of sulfur in hard water was significantly improved by all combination products versus CSL; HMWK cooks (HC) were generally more effective.
A Statistical Analysis of the Effect of Neutron Irradiation Dose and Dose Spectrum on Changes of Charpy Impact Energy for C-Mn Steels
Authors: Moskovic R , Crowde MJ , Flewitt PEJ
Published: April 2008

Statistical analyses have been undertaken using both the maximum likelihood method and Bayes paradigm on Charpy impact energy data obtained from C-Mn submerged arc weld metal specimens tested over a range of temperatures. These specimens were exposed for defined periods to a neutron spectrum containing a low ratio of thermal to fast neutrons under surveillance conditions at Magnox reactors in the UK. A subset of specimens was then exposed to a neutron spectrum of a high ratio of thermal to fast neutrons (Halden reactor, Norway). Thus the data include results obtained, whereby specimens previously exposed to irradiation in Magnox reactors under surveillance conditions were subsequently exposed to this high thermal to fast neutron dose spectrum. The result is that the upward shift in the ductile to brittle transition temperature arising from thermal neutrons saturates after a period of exposure. The statistical analyses address the contribution from neutron dose and rate to the changes in these data to evaluate the underlying contribution made by the thermal neutrons as compared with the fast neutrons. The results of the analyses are discussed with respect to the role of neutron dose and dose rate together with known metallurgical variables and the sensitivity to these parameters.
The Effect of Neutron Flux on Radiation-Induced Embrittlement in Reactor Pressure Vessel Steels
Authors: Stoller RE
Published: April 2008

The effect of neutron flux level is a longstanding concern for determining the applicability of test reactor data or high lead-factor surveillance data to the prediction of embrittlement in commercial reactor pressure vessels (RPV). However, as operating reactors reach higher fluences, the question of flux effects is becoming increasingly relevant for situations such as embrittlement attenuation through the (RPV) and the comparison of boiling and pressurized reactor RPVs. In spite of its technological importance and extensive experimental and theoretical investigation, the issue of neutron flux effects on radiation-induced embrittlement in RPV steels remains unresolved. For neutron fluxes much greater than RPV operating conditions (>100 times higher), a regime exists in which the effects of flux are well defined experimentally and are well predicted by current models. These same models predict that the effect of flux should be relatively weak for values near those obtained in commercial RPVs, but may increase at lower fluxes. However, it is difficult to obtain sufficient data at low to intermediate fluxes to unambiguously determine the effects of flux since the time required to reach the desired fluences is necessarily long. In order to demonstrate the potential effects of flux on RPV embrittlement, and to help interpret the available experiments, a kinetic embrittlement model has been used in an analysis of the primary variables involved. The results of the analysis are consistent with a modest effect of flux on embrittlement for fluxes near those typical of commercial RPVs.