bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determining Bentonite Content in Soil-Bentonite Mixtures Using Electrical Conductivity
Authors: Abu-Hassanein ZS , Benson CH , Wang X , Blotz LR 
Published: February 2009

Abstract
A procedure based on electrical conductivity is described for measuring bentonite content in soil-bentonite mixtures having a wide range of bentonite contents. Standard equipment used for sedimentation analysis and an electrical conductivity meter are required. The procedure employs calibration curves relating electrical conductivity and bentonite concentration for soil-bentonite-water slurries. Calibration curves are presented for two sand-bentonite mixtures, a mixture of bentonite and waste mine rock, and two fine-grained soils mixed with bentonite.
Water Pressure Measurement with Time Domain Reflectometry Cables
Authors: Dowding CH , Huang F , McComb PS 
Published: February 2009

Abstract
Attributes of the remote measurement of piezometric water pressure and water level with time domain reflectometry (TDR) techniques are investigated. The evaluation includes a two-wire system for unusually small riser tubes as well as parallel wire and air-filled or hollow coaxial cable for typical installations. Comparison of TDR cable and commercial pressure transducer technology shows coaxial cable TDR systems with distance crimps capable of equaling and exceeding the resolution of pressure transducers. Crimps provide permanent distance markers that allow the TDR system to be self-calibrating.
Pressuremeter Testing in Arid Collapsible Soils
Authors: Smith TD , Rollins KM 
Published: February 2009

Abstract
An introduction to soil mechanics limitations, testing concerns, and deposition of collapsible soil from the arid western states in the U.S. is presented. Laboratory evaluation of their properties for routine foundation engineering bearing capacity and settlement is of limited use. In situ testing is shown to be practical and successful in a wide range of soil types from uniform fine-grained soils to silty-sandy gravels. The hydraulic, monocell, prebored pressuremeter is proposed as an in situ test to establish dry, wet, and dry-wet geotechnical parameters for design by three testing procedures. Each procedure is given a detailed description, typical results are presented for collapsible debris fan deposits, and application of the procedures to routine foundation design is discussed. Simple collapse categories are introduced based on the pressurementer stiffness change from dry to wet conditions. Two minor modifications to the commercial pressuremeter probe end shoe and top support collar are recommended to ensure uniform radial water migration. Estimates of the depth of collapse from subsurface soil beneath existing foundations undergoing excessive settlement are also possible.
Comparison of Laboratory-Measured GCL Hydraulic Conductivity Based on Three Permeameter Types
Authors: Petrov RJ , Kerry Rowe R , Quigley RM 
Published: February 2009

Abstract
Specimen preparation, installation, and testing procedures are presented for testing a needle-punched geosynthetic clay liner (GCL) in a consolidation-type, fixed-ring constant-flow-rate hydraulic conductivity apparatus. The proposed approach is illustrated by reporting the results obtained for a GCL statically confined to effective stresses of ∼3 and ∼35 kPa, hydrated and permeated with distilled water and concentrated aqueous salt solutions (0.6 and 2.0 N NaCl), and sequentially permeated with concentrated aqueous salt solutions (0.6 and 2.0 N NaCl) after initial permeation with distilled water. The issue of potential preferential sidewall flow in the fixed-ring permeameter tests was then addressed by comparing results with those conducted under otherwise similar testing conditions in a double-ring and flexible-wall permeameter. Reasonable reproducibility of the test results was obtained between the different types of permeameters, suggesting that, if present, preferential sidewall flow was negligibly small and was not significant on the calculated hydraulic conductivity values. This conclusion was found to be valid for the range of permeant types (distilled water and 0.6 and 2.0 N NaCl), static-confining stresses, and hydrating mediums considered. Premature arrival of the salt solution front in the effluent (i.e., solute breakthrough) during fixed-ring hydraulic conductivity testing was explained as a probable diffusion-dominated transport mechanism through the relatively thin GCL specimens.
Particle-Size Analysis of Soils Using Laser Light Scattering and X-Ray Absorption Technology
Authors: Vitton SJ , Sadler LY 
Published: February 2009

Abstract
The particle-size distribution for the fine-grained fraction of eleven soil samples was determined using four commercially available, state-of-the-art automated particle-size distribution analysis instruments. Two of the instruments operate on the principle of interaction of laser light with soil particles suspended in water in a highly agitated state, and two operate on the principle of the absorption of an X-ray beam by a suspension of soil particles settling in a quiescent column of water. The results from each instrument for each soil sample were compared to size analysis data determined by the hydrometer technique. The X-ray absorption instruments produced particle-size distributions very close to those of the hydrometer method, with the exception of soils with high mica concentrations. The laser-based instrument data did not agree as well with the hydrometer data, although for soils with significant mica contents the results were closer than the results from the X-ray absorption instruments. Based on these results, however, it appears that the automated X-ray absorption/sedimentation-based instruments show promise as alternatives or as a possible supplement for the manual hydrometer method of size analysis for soils without significant mica particle concentrations.
Experimental Nailed Soil Walls
Authors: Ramalinga Raju GV , Wong IH , Low BK 
Published: February 2009

Abstract
Normal gravity model tests were carried out in a trench to study the influence of several design parameters on the behavior of nailed soil-retaining walls. Six nailed walls were built by varying the nail length, nail inclination, and the method of nail installation. The construction of each wall involved gradual placement of 36 m3 of sand using a clamshell attached to an overhead traveling crane, followed by excavation (in front of the facing) and installation of model soil nails. Each completed nailed soil wall and its retained sand measured 3.0 by 3.0 m in plan and was 2.4 m high before placement of surcharge fill. This paper describes the method adopted for reducing side wall friction, the sand placement procedure, the checks on uniformity and reproducibility of the relative density of the sand, the instrumentation, and the stage-by-stage excavation and nailing process. A summary of monitored results of all the tests is presented, and the results of Test 1 are discussed in detail.
Influence of Intersection Angle at Single-Well Flow Tests in Fracture-Wellbore Systems
Authors: Aydin A 
Published: February 2009

Abstract
The intersection angle between a hydraulically effective fracture and an active wellbore influences the response observed in single-well tests. An experimental study was launched to investigate the ability of a semi-analytical model proposed to account for this influence. The setup designed for this purpose includes three distinct fracture-wellbore system models with 90°, 20°, and 10° intersection angles, each assembled into a steel box frame to provide a constant fracture aperture during testing. The laboratory program involved testing each of these models for three different fracture apertures under steady, constant-flux, injection, and pumping conditions. The overall experimental setup successfully simulated the conceptual testing environment in which the mathematical model is expected to reproduce. Analysis of the test results confirmed the effectiveness of the conceptual model in refining the predictions of single-well tests. Important applications include the determination of anisotropic rock-mass permeability in a single, arbitrarily oriented wellbore by isolating fractures of different sets and of optimum wellbore orientation and spacing for maximum efficiency of producing wells.
Improved √t Method to Evaluate Consolidation Test Results
Authors: Tewatia SK , Venkatachalam K 
Published: February 2009

Abstract
Taylor (1948) suggested the method for determination of the settlement, δ, corresponding to 90% consolidation utilizing the characteristics of the degree of consolidation, U, versus the square root of the time factor, √T, plot. Based on the properties of the slope of U versus √T curve, a new method is proposed to determine δ corresponding to any U above 70% consolidation for evaluation of the coefficient of consolidation, Cv. The effects of the secondary consolidation on the Cv value at different percentages of consolidation can be studied. Cv, closer to the field values, can be determined in less time as compared to Taylor's method. At any U in between 75 and 95% consolidation, Cv(U) due to the new method lies in between Taylor's Cv and Casagrande's Cv.
Book Review
Authors: Fourney WL 
Published: February 2009

Abstract
The purpose of this book is to demonstrate the use of fracture mechanics in describing structural behavior leading to failure of quasi-brittle materials. It is intended as a textbook for a graduate course in civil engineering, engineering mechanics, or allied disciplines. It could be used as a supplementary text for courses in advanced concrete theory and as a reference text for the practicing engineer. It draws upon the research findings of the authors and others over the last two decades in the applications of fracture mechanics as applied to cracking, damage, and fracture of plain and reinforced concrete structures and rock masses.
Revised Incremental J-Integral Equations for ASTM E1820 Using the Crack Mouth Opening Displacement
Authors: Zhu Xian-Kui , Joyce James A. 
Published: February 2009

Abstract
The incremental J-integral equations used in ASTM E1820 were developed utilizing the work input to the test specimen, and utilize the load versus load-point/line displacement (LLD) data obtained from the fracture test. The analysis of Ernst et al. [Fracture Machanics: Thirteenth Conference, ASTM STP 743] was then used to obtain crack growth corrected estimates of the J-integral as needed for an accurate J-R curve evaluation. For the compact type specimens, the crack mouth opening displacement (CMOD) gage was moved to the load line so that an adequate estimate of LLD could be obtained from the clip gage and utilized for compliance-based crack extension and incremental J-integral estimates. For the single edge-notched bend [SE(B)] specimens, however, it has been necessary to measure both CMOD for compliance-based crack length estimates and LLD for the crack growth corrected J-integral calculations. Additional experimental complexity and expense are thus added. ASTM E1820 includes a “basic” procedure which allows evaluating the J-integral using CMOD without crack growth corrections if the result is used only for evaluation of initiation toughness. Recently, Annex A16 based on work of Wallin and Laukkanen [Engineering Fracture Mechanics, Vol. 71, 2004, pp. 1601–1614] has been added to ASTM E1820 that presents a multiple-step procedure to obtain a crack growth corrected J-R curve from the basic method data. A more direct approach was proposed recently by Zhu et al. [Journal of ASTM International, Vol. 5, No. 5, 2008, paper ID: JAI 101532] using an incremental procedure to obtain the desired, crack growth corrected J-R curve from the CMOD data of SE(B) specimens with two geometry factors ηCMOD and γCMOD similar to the parameters presently used in the existing LLD-based J-integral analysis. Using fracture toughness test data for SE(B) specimens, detailed comparisons and discussions are made between the proposed method and the ASTM E1820 CMOD methods in determination of J-R curves for HY80 steels. As the basis of comparison, the “accurate” solutions obtained from the standard LLD-based incremental J-integral method are provided for all specimens considered. The difference between the CMOD and LLD methods are then quantified. The results show that the proposed CMOD incremental J-integral equations are simple and effective, and thus are recommended here for use in ASTM E1820 for testing J-R curves and for reducing test costs and complexity.
Medullary thyroid carcinoma identified within the first year of life in children with hereditary multiple endocrine neoplasia type 2A (codon 634) and 2B
Authors: Zenaty D , Aigrain Y , Peuchmaur M , Philippe-Chomette P , Baumann C , Cornelis F , Hugot J P , Chevenne D , Barbu V , Guillausseau P J , Schlumberger M , Carel J C , Travagli J P , Léger J 
Published: February 2009

ContextEarly prophylactic thyroidectomy in patients with multiple endocrine neoplasia (MEN) type 2 offers the best chance for a normal life expectancy.ObjectiveTo analyze the results of thyroidectomy performed during the first year of life in six patients with MEN 2A (codon 634) or MEN 2B (codon 918) syndrome.Design and settingA university hospital-based prospective study from 2001 to 2008.Subjects and methodsSix family members affected either by MEN 2A (n=3) or MEN 2B (n=3) syndrome were identified through neonatal genetic screening.ResultsTotal thyroidectomy was performed at a median age of 0.8 year in the six patients, with central lymph node dissection in five. Bilateral millimetric medullary thyroid carcinoma (MTC) was found in all patients, with a unilateral lymph node micrometastasis in two of the three MEN 2B patients. Before thyroidectomy, MEN 2B patients had much higher basal serum calcitonin levels than those with MEN 2A and controls. After thyroidectomy, with a median follow-up of 3.3 years, the six patients had no evidence of persistent MTC.ConclusionBilateral millimetric MTC may be present during the first year of life in these patients, with lymph node metastases also occurring in MEN 2B patients. These results support a total thyroidectomy at the age of about one year in MEN 2A (codon 634) children with an abnormal serum calcitonin level, and a total thyroidectomy with central neck dissection within the first weeks of life in MEN 2B patients.
Movement and Recolonization of Potomac Sculpin in a Virginia Stream
Authors: Hudy Mark , Shiflet Jeremy 
Published: February 2009

Abstract
Movement patterns of benthic fishes have not been widely studied, but an understanding of those movement patterns may be necessary in assessing the full effects of habitat fragmentation and the need to restore connectivity in fragmented watersheds. We evaluated nonspawning movement of 3,353 marked Potomac sculpin Cottus girardi over a 1-year period on a 3.14-km segment of a third-order stream. In addition, we conducted a fish removal experiment at the pool–riffle sequence scale (90 m) to evaluate the effects of fish density on movement and recolonization rates. The majority of recaptured Potomac sculpin stayed within 30 m of their original capture location throughout the study (81% at 30 d; 64% at 75 d; 53% at 363 d). Upstream (US) movement was greater than downstream (DS) movement at 30 d (US 17%; DS 3%), 75 d (US 30%, DS 6%) and 363 d (US 32%, DS 15%). After 75 d, 10% of the fish that moved upstream moved more than 250 m (21% after 363 d). The maximum distance moved was 1,711 m in 75 d. There were no significant differences in mean total length between recaptured Potomac sculpin that either moved or did not move or between upstream and downstream movers. The presence or absence of fishes in adjacent 30-m habitat sections influenced upstream, but not downstream, movement of Potomac sculpin. After 30 d, Potomac sculpin population densities and size structure were similar between fish removal and reference sections. We found our results to be similar to those of other studies, which found that, on average, freshwater sculpin are sedentary. However, we identified great dispersal capabilities (&gt;250 m) for a small percentage of Potomac sculpin. The long dispersal distances suggest that this typically sedentary species may need greater habitat connectivity than previously assumed.
Will It Float? Testing a New Technique for Reducing Loggerhead Sea Turtle Damage to Crab Pots
Authors: Avissar Naomi , Hazen Elliott , Young Nancy , Crowder Larry 
Published: February 2009

Abstract
Loggerhead sea turtles Caretta caretta have been found to damage crab pots and reduce catch of blue crabs Callinectes sapidus in North Carolina sounds. In response, crabbers have avoided fishing at locations and times of peak loggerhead sea turtle activity and have experimented with modifications to make their gear more robust. We field tested a new, lightweight, and inexpensive modification: self-righting floats tethered to the inside of the crab pots. Thirty pairs of regular and modified pots were fished between 16 June and 31 July 2006. Damage by loggerhead sea turtles was found in 38% of all replicates, and blue crab catch was 57% lower in crab pots that had been discovered by loggerhead sea turtles. The float modification effectively reduced damage, but stronger effects were found when using plastic bait-well covers that the crabbers had introduced. The modified pots were significantly less damaged (average damage index [ADI] = 1.38 with plastic covers and 2.01 with cardboard covers) than regular pots (ADI = 1.78 with plastic covers and 2.38 with cardboard covers). Average blue crab catch was significantly higher in pots with plastic bait-well covers (15 crabs/modified pot, 18 crabs/regular pot) than in pots with cardboard covers (13 crabs/modified pot, 11 crabs/regular pot). However, there was a significant interaction of pot type with bait-well cover type. When plastic covers were used, average blue crab catch was higher in regular pots (18 crabs/pot) than in modified pots (15 crabs/pot). The opposite case was observed when cardboard covers were used: catch was higher in modified pots (13 crabs/pot) than in regular pots (11 crabs/pot). A drawback to the float modification was a qualitative increase in pot drift and loss in high winds, resulting in the need for costly retrieval measures; crab pot loss may also jeopardize estuarine species that become trapped in derelict gear. Adopting these techniques, however, may help crabbers reduce gear damage, catch loss, and negative interactions with loggerhead sea turtles in this fishery.
Effectiveness of Salmon Carcass Tissue for Use in DNA Extraction and Amplification in Conservation Genetic Studies
Authors: Baumsteiger Jason , Kerby Jacob L. 
Published: February 2009

Abstract
A key concern in conservation genetic studies is obtaining viable DNA for analysis. In Pacific salmon Oncorhynchus spp., carcasses represent a feasible alternative for obtaining this tissue. However, the relative speed with which a salmon carcass decomposes can affect the quality of the extracted DNA. We extracted DNA from three different tissues (anal fin, operculum, and scales) obtained from carcasses of Chinook salmon O. tshawytscha at three different levels of decomposition (slight, moderate, and extensive). Freshly euthanized fish were included as a control. Extraction of DNA was accomplished using two common methods: the Chelex method and the Qiagen DNeasy spin column method. For each extracted sample, polymerase chain reaction (PCR) was used to amplify one small microsatellite locus (170–375 base pairs [bp]), one large nuclear locus (971 bp), and one large mitochondrial locus (1,300 bp). Results suggest that DNA suitable for PCR amplification at all three loci can be readily obtained from carcasses with slight decay. Qiagen spin columns appeared to provide the best extraction method, and fin clips were the optimal tissue type. Qiagen spin columns were the only extraction method that yielded DNA suitable for PCR from carcasses with moderate to extreme decay, although positive results were less reliable. Chelex extractions proved effective for amplifying small microsatellite loci from fin and scale samples but only those from carcasses with slight decay. With further optimization of techniques, we believe salmon carcasses can be used as a suitable source of tissue for DNA extraction and subsequent study in a conservation genetics framework.
The Effects of Violating Hardy–Weinberg Equilibrium Assumptions on a Cluster-based Population Mixture Analysis of Steelhead Populations in Southeast Alaska
Authors: Masuda Michele , Thrower Frank , Nichols Krista M. 
Published: February 2009

Abstract
Clustering methods for population mixture analysis assign individuals probabilistically to populations based on their multilocus genotype data. An assumption of the methods is that loci satisfy Hardy–Weinberg equilibrium (HWE) conditions within populations. We observed that violating this assumption by including loci measured as deviating from HWE in baseline samples for the mixture analysis at times introduced extra structure into the mixture sample, leading to biased composition estimates and overestimation of the number of populations. Provided that samples from at least some contributing populations are available and that baseline samples can safely be assumed to come from single populations, then a conservative approach to mixture analysis would be to include only those characters that conform to HWE in the baseline samples, but this approach could result in a loss of resolving power. To address this problem, we outlined an ad hoc method of selecting loci for their use in mixture analysis based on individual analyses of baseline samples. A subset of loci is selected for mixture analysis based on whether the loci contribute additional structure in the baseline populations, assuming that (1) baseline samples come from single populations and (2) any subpopulation structure resulting from the inclusion of loci measured as deviating from HWE is artifactual. Given that the final set may include only a few loci, the method would be most useful for small problems. We demonstrated the method on two sets of microsatellite loci (10 and 17 loci) genotyped in steelhead Oncorhynchus mykiss sampled at Sashin Creek in southeast Alaska. The method for selecting loci for mixture analysis generally reduced bias in and improved the precision of composition estimates and reduced the overestimation of the number of populations.