bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-linear intramolecular interactions and voltage sensitivity of a KV1 family potassium channel fromPolyorchis penicillatus(Eschscholtz 1829)
Authors: Klassen Tara L. , O'Mara Megan L. , Redstone Megan , Spencer Andrew N. , Gallin Warren J. 
Published: October 2008

SUMMARYVoltage sensitivity of voltage-gated potassium channels (VKCs) is a primary factor in shaping action potentials in excitable cells. Variation in the amino acid sequence of the channel proteins is responsible for differences in the voltage range over which the channel opens. Thus, understanding how changes in voltage sensitivity are effected by changes in channel protein sequence illuminates the functional evolution of excitability. The KV1-family channel jShak1, from the jellyfish Polyorchis penicillatus, differs from most other KV1 channels in ways that are useful for studying the problem of how voltage sensitivity is related to channel sequence. We assessed the contributions of changes in sequence of the S4, voltage sensing, helix and changes in one asparagine residue in the S2 helix, to the relative stability of the open and closed states of the channel. Mutation of the neutral S2 residue (Asn227) to glutamate stabilized the open conformation of the channel. Different modifications of charge and length in S4 favoured either the closed conformation or the open conformation. The interactions between pairs of mutations revealed that some of the S4 mutations alter the conformation of the voltage-sensing domain such that the S4 helix is constrained to be closer to the S2 helix than in the wild-type conformation. These results, taken in conjunction with three-dimensional models of the channel, identify intra-molecular interactions that control the balance between open and closed states. These interactions are likely to be relevant to understanding the functional characteristics of members of this channel family from other organisms.
The Vane Cone: A New Device for Soil Shear Strength Measurement
Authors: Youssef A-FA 
Published: October 2008

Abstract
A considerable number of in-situ tests have been devised for measuring field soil shear strength parameters. These tests include, among many others, cone penetration and vane shear devices. The conventional form of each of these two devices controls the type of soil deformation, which may limit the use of the measured soil shear resistance data. In this study both vane and cone devices were combined together in one device known as vane-cone apparatus. The use of this apparatus allows deforming the soil vertically and tangentially. Consequently, the related vertical and tangential soil shear resistances can be measured. Theoretical plasticity analysis of cohesive soil is used to predict the radial and tangential stress distribution around a cone with different apex angles. Using both of these stress distributions, a relation between vane-cone resistances and soil shear strength parameters is developed. Experimental data are used to verify the developed analysis and to compare between the vane, cone, and vane-cone devices.
Horizontal and Vertical Swell Pressures from a Triaxial Test: Feasibility Study
Authors: Johnson LD 
Published: October 2008

Abstract
Horizontal and vertical swell pressures of some anisotropic undistrubed soil specimens are measured in a double chamber triaxial cell. The equipment is also capable of measuring consolidation and strength parameters of the soil. Preliminary test results indicate no difference in swell pressure between vertical and horizontal orientations of the specimen when subject to no volume change.
Temperature Effect on Preconsolidation Pressure
Authors: Tidfors M , Sällfors G 
Published: October 2008

Abstract
A change in temperature is known to affect the deformation properties of a clay specimen. In order to study the effect quantitative y and its dependence on clay type a number of oedometer tests were carried out. Conventional incremental oedometer tests as well as constant-rate-of-strain tests were used. Test results clearly show that the preconsolidation pressure decreases with increasing temperature; the compression modulus is little affected. Five different clays were tested, and the change in preconsolidation pressure was found to be larger for higher clay content of the specimen. The research shows that laboratory testing at different temperatures gives the necessary information for the calculation of temperature induced settlements.
Status of the AASHTO Accreditation Program
Authors: Steele GW 
Published: October 2008

Abstract
The American Association of State Highway and Transportation Officials (AASHTO) approved the establishment of the AASHTO Accreditation Program (AAP) in February 1988 and the first laboratory was accredited in June 1988. The objective of the AAP is to provide a mechanism for formally recognizing the competency of construction materials testing laboratories to carry out specific tests on soils, asphalt cements, cutback asphalts, emulsified asphalts, bituminous concrete mixtures, concrete aggregates. AAP is structured to comply with ASTM Standards, Guide for Laboratory Accreditation Systems (E 994) and Practice for Generic Criteria for Use in the Evaluation of Testing and Inspection Agencies (E 548), and International Standards Organization (ISO) Guide 25. AASHTO has assigned responsibility for administering the program to its Highway Subcommittee on Materials. Information on the program scope, operational procedures, and current status are given.
X-Ray Radiographic Investigation of Perchloroethylene Migration at the Livingston Derailment Site
Authors: Ferrell RE , Arman A , Grosch JJ 
Published: October 2008

Abstract
X-ray radiography of soil cores was used as the primary test method to determine the reasons for the permeation of perchloroethylene into apparently impermeable clay layers at a hazardous chemical spill site. X-ray powder diffractometry, scanning electron microscopy, and chemical analysis were also performed to characterize the materials and structures observed in the soil cores through X radiography and to verify the presence or absence of perchloroethylene.
X-ray radiography proved to be an invaluable tool in the examination of the soil structure and in the solution of the problem. Results showed the presence of a three-dimensional network of iron-lined fissures, concretions, and roots in otherwise low permeability clay. These conduits were responsible for the rapid permeation of the perchloroethylene.
Dynamic Behavior of the Bumpy Road Shaking Table System
Authors: Lee F-H , Schofield AN 
Published: October 2008

Abstract
Vibration tests were performed on the “bumpy road shaking table” system at the Cambridge University Geotechnical Centrifuge to investigate its dynamic behavior under operating conditions. In these tests, steel plates of known weights were fastened onto the base of the model container. The container was then subjected to “earthquake motions” simulated by the shaking table system and the accelerations of various parts of the system measured by means of accelerometers. The test results show that the bumpy road wheel acceleration has a substantial amount of high-frequency components. During earthquake tests, the bumpy road container is isolated from this high-frequency motion by the flexibility of the package-transmission assembly. The results also suggest that the bumpy road package-transmission assembly has a resonance mode at about 85 Hz while the centrifuge arm has a resonance mode at about 104 Hz. If the excitation frequency is close to the package-transmission frequency of 85 Hz, a strong response is obtained from the bumpy road system, and package motion is highly harmonic and relatively “clean.” On the other hand, if the excitation frequency is close to the resonance frequency of the centrifuge arm, the latter is excited into motion instead of the container and soil model.
Model Studies of Pressuremeter Testing in Soft Rock
Authors: Haberfield CM , Johnston IW 
Published: October 2008

Abstract
In order to simulate pressuremeter testing in soft rock, a series of detailed model tests were undertaken under carefully controlled conditions in the laboratory. The technique employed made use of a modified triaxial cell in which thick walled cylindrical specimens of a synthetic soft rock, subjected to constant external confining pressures, were tested to failure. Pressure was applied in increments to the internal cavity, and measurements were made of cavity and specimen volume changes under fully drained conditions. This paper describes the pressuremeter simulation tests, giving details of test techniques and results.
Chemical Impregnation of Cohesionless Soils
Authors: Schneider HR , Chameau J-L , Leonards GA 
Published: October 2008

Abstract
Existing methods to obtain and test high-quality undisturbed samples of cohesionless soil below the water table depend at some stage on freezing. This limits the range of application to relatively clean sands, and even for those soils the freezing operation is delicate, time-consuming, and costly. Moreover, there is no direct way to check, independently, the effects of the freezing process on the subsequent behavior of the sample. Recognition of these limitations motivated the search for an alternate method, namely, chemical impregnation. After many trials, agar, a natural polymer, has been identified as a potential impregnation material for developing an alternate sampling technique.
Agar powder dissolves readily in water at a temperature of about 85 to 95°C to form a clear solution of low viscosity. On cooling, the solution remains liquid until a gelation temperature of 35 to 40°C is reached, when the mass sets to a rigid gel even at low concentrations, such as 1% or less. The gel does not melt again when immersed in water or during handling, but it can be reliquefied at a temperature above the gelation temperature.
This paper presents the results of tests to examine the suitability of agar as an impregnation material to permit undisturbed sampling of sands below the water table. Field trials were made to demonstrate the feasibility of the impregnation process.
Moisture Content and Density of Smectites
Authors: Post JL 
Published: October 2008

Abstract
The measured density of smectites, using ASTM Test Method for Specific Gravity of Soils (D 854) and ASTM Method for Laboratory Determination of Water (Moisture) Content of Soil, Rock, and Soil-Aggregate Mixtures (D 2216), vary as a function of heating temperature and time. For example, the measured moisture content of air-dry Otay bentonite, heated to 110°C, varied from 16.48% moisture to 19.0% moisture for 18- to 96-h heating time giving a calculated specific gravity varying from 2.679 to 2.785, and a measured variation in equilibrium temperature from 100 to 130°C gave a calculated specific gravity varying from 2.744 to 2.857. Measured specific gravity values of these smectite clays, for constant mass at 110°C, range from 2.785 to 3.150, whereas the calculated values for the smectites, including the essential bound water, range from 1.98 to 2.14. The maximum oven-dry density of compacted Otay bentonite varied from 1354 to 1384 kg/m3 (84.5 to 86.4 lb/ft3), with optimum moisture contents from 29.0 to 27.2% when possible temperature and time variations in moisture determination were observed, using ASTM Test Method for Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10-lb (4.54-kg) Rammer and 18-in. (457-mm) Drop (D1557). The bound water of the smectite is considered part of the moisture content when a compaction curve is prepared.
Pulse Shapes from Ground Penetrating Radar
Authors: Reames FM 
Published: October 2008

Abstract
A number of technical reports have discussed the use of ground penetrating radar equipment in examining highway structures for deterioration. Several of these reports provide expressions or calculational techniques that purport to describe the shape of the radar pulse returning from voids within the structure, such as the thin air gap at a delamination within a concrete bridge deck or the larger voids that can develop between a concrete slab and the soils beneath. None of the theories has been developed with the use of correct electromagnetic theory (Maxwell's equations and a two-interface reflection coefficient); it is not surprising, therefore, that the pulse shape computations and observed pulse shapes sometimes fail to agree. In this paper the correct means of computing the shape of radar pulses returning from voids is presented with some results, and new approaches for computerized detection of structural defects are discussed.
A Cyclic Undrained Simple Shear Testing Method for Soils
Authors: Tatsuoka F , Pradhan TBS , Yoshi-ie H 
Published: October 2008

AbstractAn undrained simple shear testing method for soils using a torsional shear apparatus is described, in which a hollow cylindrical specimen is sheared under plane strain conditions without deforming and rotating all horizontal planes. In this testing method, the simple shear deformation mode is achieved only by several mechanical means without using an automated pressure control system. Typical results of cyclic undrained simple shear tests using uniform cyclic shear stresses on one-dimensionally consolidated saturated sand are presented. A similar undrained testing method with the same inner and outer lateral confining pressures, in which the simple shear condition is satisfied only in an approximated way, is also described. The test results show that the deviation of the stress-strain behavior in the approximate testing method from that under the exact simple shear condition increases as the shear strain increases. However, it was also found that for the purpose of evaluating cyclic undrained simple shear strength values defined by the amplitude of cyclic shear strain, the use of this approximate testing method is justified.Some typical stress-strain relationships are also presented in detail. It is shown that despite large changes in the effective axial stress during cyclic undrained loading, the relationships between the ratio of the shear stress to the effective axial stress and the shear strain are of a smooth hyperbolic type. Further, it is shown that in a cyclic undrained simple shear test, the angles of the directions of the major principal strain increments rotate discontinuously between ± 45° relative to the axial stress direction. Consequently, the angles of the directions of the principal stress also change rather discontinuously, and at relatively large strains, it becomes almost ± 45° relative to the axial stress direction.
The Use of Proximity Transducers for Local Strain Measurements in Triaxial Tests
Authors: Hird CC , Yung PCY 
Published: October 2008

Abstract
A description is given of an instrumentation system suitable for measuring axial and radial strains locally in the central region of a triaxial specimen. The system is primarily intended to measure small strains and is one of several that may be employed to avoid errors associated with conventional measurements. A theoretical assessment is made of the accuracy achieved at strains of up to 0.1%. Experimental results are also presented to illustrate the extent of various random errors.
In Situ EIS Measurements of Irradiated Zircaloy-4 Post-Transition Corrosion Kinetic Behavior
Authors: Rishel D. M. , Eklund K. L. , Kammenzind B. F. 
Published: October 2008

Abstract
Under irradiation the post-transition corrosion rates of Zircaloy are enhanced relative to out-of-flux rates. In an effort to better understand the effects of different mixed-field radiation environments and the variables that may contribute to this enhancement a series of in situ electrochemical impedance spectroscopy (EIS) tests were conducted in the Halden Test Reactor under PWR type conditions. The EIS tests were conducted using five identically fabricated electrode cells, which employed Zircaloy-4 tipped working electrodes. Approximately 30 μm thick oxides were prefilmed on the electrode tips prior to test insertion. The electrode test train was designed in a manner that enabled a wide range of gamma and neutron radiation flux conditions to be evaluated. Gamma fluxes (E ≥1 MeV) ranged from 1.7×1013 to 1.3×1014 cm−2 s−1 while the fast neutron fluxes (E ≥1 MeV) ranged from 2.9×1010 to 3.2×1013 cm−2 s−1. In addition, the EIS tests were conducted over temperatures ranging from 250 to 335°C. Electrode sets were situated into two basic radiation environments, which were differentiated by the magnitude and relative proportion of the mixed radiation field. In one environment, where the fast neutron flux was low, the relative gamma radiation component was high (i.e., high gamma-to-neutron ratio environment). In the other environment, where the fast neutron flux was high, the relative gamma radiation component was low (i.e., low gamma-to-neutron ratio environment). Based on the low frequency limits, the impedance moduli and inferred corrosion rates were found to be a complex function of temperature, and the relative proportion of gamma and neutron radiation. At low temperatures of 250°C it was found that the electrode sets which were exposed under high gamma-to-neutron ratios exhibited low frequency impedances that were almost 2.5 times lower than the case for the electrode sets which were placed in low gamma-to-neutron ratio. This occurred even though the absolute magnitude of the gamma and neutron flux fields decreased. This would imply that the corrosion rate is higher under high gamma-to-neutron ratios than under low gamma-to-neutron ratios. Conversely, at high temperatures, 335°C, only very small differences in impedance were noted as a function of radiation environment. Post-test destructive examination of the Zircaloy tipped electrodes indicates that the growth of the oxide formed during the in-pile phase of testing is consistent with the in situ EIS measurements obtained in-pile. The porous nature of the post-transition oxide coupled with the apparent correlation with gamma radiation suggests that heterogeneous radiolysis within the corrosion product film plays an important role in enhancing post-transition corrosion kinetics.
Safety in Big Jumps: Relationship Between Landing Shape and Impact Energy Determined by Computer Simulation
Authors: Böhm Harald , Senner Veit 
Published: October 2008

Abstract
With the increasing popularity of freestyle skiing and snowboarding many ski resorts constructed their own terrain parks including several jumps, rails, and pipes. In order to prevent risks of high-impact injuries in jumping, an adequate construction of the landing hill is very important. In professional ski jumping this can be achieved by designing the landing area profile so that its curvature follows the flight path of the jumping athlete. Classical kicker shapes do not follow this principle. They consist of a ramp subsequently followed by a flat table and a descending landing area. Construction of these kickers is commonly made by trial and error. To make the construction process safer and reduce unnecessary risks, a guideline for save kicker construction based on multiple simplifications of the real situation was published in the literature. The purpose of this study was to investigate how this guideline applies to the situation in a real kicker. Two skiers and three snowboarders performed a total of eleven jumps on one expert’s kicker (table length 17 m, transition angle 20°, and kick-off height 2.5 m). Computer simulations, based on the take-off velocities of the eleven jumps measured, were used to calculate the impact energy during landing on different table lengths combined with different landing slopes. If the jumper fails to adjust take-off velocity to account for the shorter deck length, the sum of the impact energies of the simulated jumps will increase dramatically at table lengths smaller than 15 m combined with a landing steepness greater than 20. The predictions based on the guideline (16 m table length and 33° landing steepness) are within a safe region. The guideline is therefore applicable for the experts kicker investigated.
Assessment of the Ozone Formation Potential from Pesticide Solvents Using a Mobile Ozone Chamber Assay Approach
Authors: Kumar Anuj , Yang Wenli , Howard Cody J. , Kleeman Michael J. , Derrick Doniche , Green Peter G. 
Published: October 2008

Abstract
The use of pesticides in California’s agricultural industry plays a role in air quality with emissions of organic compounds thought to contribute to the formation of ground level ozone. Ozone levels in many regions of California exceed the prescribed Federal and State standards every year. The actual contribution from pesticide applications (as well as other agricultural sources) is largely unknown, and relies on assumptions of reactivity and tendency to evaporate. Progress on accurate determinations of either parameter is limited by many factors, including the proprietary nature of formulations. We have developed an approach which can measure the ozone formation potential of many agricultural sources, in the field. This approach was previously validated and described during a recently completed and published study of emissions from dairy cattle, their feed, as well as their fresh waste. With accompanying measurements of the most abundant volatile organic compounds (VOCs) involved there, we showed agreement between laboratory studies, field measurements, and a computer model of atmospheric photochemical reactions that improves upon past efforts, which were limited to urban/industrial VOCs. Our goal is to reach the same level of understanding for VOCs contained in pesticide formulations.
Two sets of field experiments were performed to assess the ozone formation potential of pesticide solvents using a set of transportable smog chambers in the summer of 2007. The first set of experiments were conducted for a solvent-based emulsifiable concentrate (EC) base-spray on a one-acre bare field, and the second set of experiments were conducted for an agricultural application of Lorsban 4E in a three-acre citrus orchard. By comparing the upwind and downwind measurements, the experiments indicated that the emission of pesticide solvent after field application led to increased ozone formation. After a 180 min UV exposure, the ozone formation potential measured at the downwind side averaged 14 ppb higher than that of upwind air, while the average difference was around 3 ppb for background levels on both the day before and the day after pesticide spray. Laboratory experiments were also conducted for different doses of EC base with various levels of nitrogen oxides using the transportable smog chambers. The experimental isopleth demonstrates that VOCs emitted from the EC base could result in high ozone formation. Future work will provide full VOC speciation and application of the results in a regional photochemical model to predict ozone impacts.