bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Re-Look at the Asphalt Mixture Performance Test Protocols and Computational Algorithms
Authors: Roy Neethu , Veeraragavan A. , Jain P. K. , Krishnan J. Murali 
Published: July 2013

Abstract
Asphalt mixture performance tests (AMPTs) are developed to complement the Superpave volumetric mix design procedure and to reliably measure the mechanical response characteristics of the asphalt mixtures. The AMPT protocols, such as dynamic modulus, flow time and flow number test protocols, and the computational algorithms for post-processing of data are in the development stages and require further refinement. In this investigation, AMPTs were carried out on asphalt mixtures with unmodified, polymer-modified, and crumb-rubber-modified binders. Dynamic modulus test was carried out for a wide range of temperatures and frequencies and master curves were constructed. It was observed that the American Association of State Highway and Transportation Officials (AASHTO) procedure for master curves does not take into account the influence of phase angle, and this could hinder the effective use of this input in pavement design and analysis. Flow time and flow number tests were carried out for an extended time of 100 000 s (cycles) rather than the currently practised 10 000 s (cycles) protocol. The test data was used in assessing the various algorithms for evaluating flow values. A wheel tracking test was also carried out and it was found that the response of mixtures could be correlated to wheel tracking test results in a qualitative manner to the flow time test.
Stress State of GaN Epilayer Grown on Sapphire and 6H-SiC Substrates
Authors: Zhang Kexiong , Liang Hongwei , Song Shiwei , Yang Dechao , Shen Rensheng , Liu Yang , Xia Xiaochuan , Luo Yingmin , Du Guotong 
Published: July 2013

Abstract
The stress states and influence of two opposite stress types under similar stress intensities on the structural and optical properties of GaN films grown on sapphire and 6H-SiC substrates via metalorganic chemical vapor deposition were investigated. The E2 (high) phonon shifts of Raman spectra show that tensile stresses exist in the GaN epilayer grown on 6H-SiC, whereas compressive stresses appear in the film grown on sapphire, indicating that the thermal mismatch between the epilayers and the substrates plays a major role in determining the residual stresses in GaN films. Narrower full widths at half-maximum of E2 (high) phonon and double crystal X-ray diffraction peaks and the higher E2 (high) phonon intensity are visible for the GaN film grown on sapphire, illustrating that under almost equivalent stress intensities, tensile stresses have a much more negative influence on the crystalline quality of GaN epilayers. Finally, a numerical relationship between the luminescent band gap and the biaxial stresses of the GaN films is obtained at 10 K.
Centrifuge Model Test Study of Static and Cyclic Behavior of a Pile Foundation for an Offshore Wind Generator
Authors: Zhang Ga , Rong Bing , Fu Ping 
Published: July 2013

Abstract
The use of large-diameter piles as foundations for offshore wind-driven generators has become increasingly common in recent years. These piles are usually located in saturated soft clay and experience a wide variety of static and dynamic loads. A new approach was described to simulate different types of loads on a large-diameter pile under high g levels in centrifuge model tests by simplifying the complex horizontal load combinations to which such a pile is typically subjected. A series of centrifuge model tests was conducted to assess the influence of several factors. An image-based measurement system, together with a transducer-based measurement, was used to obtain a comprehensive understanding of the response of the soil. The horizontal load-induced bending moment of the pile exhibited a nearly triangular distribution. A critical load, which can be estimated as approximately half of the ultimate load, was found to exist, beyond which the rate of displacement of the pile increased significantly with increasing load. The pile-induced deformation of the soil, concentrated within zones on both sides of the pile, gradually increased as the load increased and became nearly constant when the load was close to the ultimate load. Significant separation occurred between the pile and the neighboring soil in the upper part of the pile. The critical and ultimate loads of the pile were significantly dependent on the behavior of the soil in the upper layer, the depth, and the diameter of the pile.
Method for Dynamic Material Property Characterization of Soft-Tissue-Mimicking Isotropic Viscoelastic Materials Using Fractional Damping Models
Authors: Martin Bryn A. , Kutluay Umit , Yazicioglu Yigit 
Published: July 2013

Abstract
Characterization of the mechanical properties of human-tissue-mimicking silicone elastomers is important for producing accurate tissue models for experimentation. However, the viscoelastic and frequency-dependent material properties of elastomers are difficult to quantify. We present a material characterization technique for a silicone elastomer used to mimic human soft tissue based on generalized-Maxwell-type material models with and without fractional dissipating mechanisms. The silicone specimens were prestressed and had the shape of cylindrical rods. It was possible to consistently identify material properties of all specimen samples from different batches of the material obtained from the manufacturer. As a general trend, material models with a higher number of parameters performed better, with the exception of models with fractional order damping mechanisms. Fractional models had the highest success for nearly all the samples in representing the dynamic behavior of the elastomer in the frequency range of 5–100 Hz, where the specimen structure displays a strong modal response.
Comparator With Optical Encoder System for the Calibration of Leveling Staffs
Authors: Marjetič Aleš , Kogoj Dušan 
Published: July 2013

Abstract
Geometric leveling is the most precise and universal method used to determine heights. In order to achieve the greatest possible accuracy, the method demands a calibrated leveling staff, which requires an appropriate calibration facility. The encoded shape of the leveling staff demands the rebuilding of comparators designed for calibrating classical leveling staffs. The comparator MSGL001 at the Faculty of Civil and Geodetic Engineering in Ljubljana is based on an optical encoder system that is an original solution of snapshot positioning. The aim of this paper is to present the rebuilt comparator and the details of its testing.
A Numerical Study on Effective Modulus of Elasticity in Crack Length Evaluation for Single-Edge Bending Specimens
Authors: Wang Enyang , Zhou Wenxing , Shen Guowu 
Published: July 2013

Abstract
The actual state of stress in the remaining ligament of a single-edge bending (SE(B)) specimen, which is neither plane stress nor plane strain, is critical in accurately predicting the crack length in the specimen involved in the unloading compliance method. Three-dimensional finite element analyses were carried out in this study to evaluate the effective modulus of elasticity that reflects the actual state of stress corresponding to the crack mouth opening displacement (CMOD) compliance of the SE(B) specimen. Both plane-sided and side-grooved specimens with a wide range of geometric configurations and crack lengths were included in the study. A practical approach is further proposed to quickly evaluate the effective modulus from the CMOD compliance determined based on the test data. The proposed approach was verified using experimental data and numerical analysis results. The results of the verification suggest that replacing the elastic modulus corresponding to the plane stress or plane strain condition with the effective modulus in commonly used a/W–CMOD compliance equations can markedly improve the accuracy of the predicted crack length.
Decision Procedure for the Weibull Distribution Based on Run Lengths of Conforming Items
Authors: Aslam Muhammad , Nezhad Mohammad Saber Fallah , Azam Muhammad 
Published: July 2013

Abstract
In this study, acceptance sampling has been developed using the run lengths of conforming items for Weibull-distributed products. The plan parameters of the proposed plan were determined such that the given risks were satisfied for specified values of the mean ratio, shape parameter, and experiment time. Formulas for gamma distribution are also suggested in this paper. A comparison of the proposed plan with the existing repetitive group sampling plan was made, and the proposed plan was found to perform better than the existing sampling plan. Tables are provided for the selection of the plan parameters for inspection purposes. A real example is used to describe the plan developed here.
Optimization of Vickers Hardness Parameters for Micro- And Macro-Indentation of Grade 91 Steel
Authors: Siefert J. A. , Shingledecker J. P. , Parker J. D. 
Published: July 2013

Abstract
Hardness is being assessed as a potential life-assessment tool for tracking microstructural degradation and remaining life in creep strength enhanced ferritic (CSEF) steels. Such methodology is already being utilized for the CSEF steel Grade 91, which has been widely implemented in both replacement parts and new construction over the last two decades. Additionally, research into the complex microstructural features in welded joints often utilizes hardness surveys to characterize changes caused by thermal processing. New automated hardness testing equipment now affords the ability to develop statistically relevant datasets for these uses. However, proper application and understanding of the data requires knowledge of limitations and variations with the load and spacing of the hardness indents and the potential role of different material conditions in this complex steel. In this work, we have examined the effect of load in three Grade 91 material conditions, as well as the effect of spacing in as-received material to determine optimum parameters for both macrohardness (i.e., &gt;1 kg) and microhardness mapping (i.e., &lt;500 g). The results show that to minimize variations in microhardness and ensure consistency with macrohardness results, a 200 -g load is preferred for characterization. Laser scanning microscopy was utilized to clarify the potential for indentation size effects (ISE).
A Method to Obtain Straight Crack Fronts During Pre-Cracking of Compact Tension Specimens
Authors: Öberg Martin 
Published: July 2013

Abstract
A common problem during pre-cracking of compact tension (CT) specimens is skewed crack fronts. It is also one of the most common reasons for which tests according to, for instance, ASTM E1820-11: Standard Test Method for Measurement of Fracture Toughness, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2012, do not give valid results. This problem is normally a result of the fact that specimens and fixtures are not perfectly aligned, even when the testing setup meets the requirements of ASTM standards. In the present investigation, aluminum bushings have been used to rearrange the loads transferred from the testing machine to the specimens. Geometrical errors were deliberately introduced to the testing setup so that the specimens were asymmetrically loaded. The introduced errors were, however, within the tolerances of ASTM standards. Steel specimens with two different notch types, Chevron and straight notches, were tested, both with and without aluminum bushings. The specimens were pre-fatigued and thereafter broken under monotonic loading. The specimen crack lengths were measured and validated according to ASTM E1820-11. The results related to pre-fatigued specimens with aluminum bushings were shown to be valid, whereas the results for specimens without bushings did not meet the ASTM standards requirements.
Medullary thyroid carcinoma and duodenal calcitonin-secreting neuroendocrine tumour: more than coincidence?
Authors: Huguet I , Lamas C , Vera R , Lomas A , Quilez R P , Grossman A , Botella F 
Published: July 2013

Summary
Neuroendocrine tumours (NETs) are a heterogeneous group of neoplasms whose management can be problematic. In many cases, multiple tumours may occur in the same patient or his or her family, and some of these have now been defined genetically, although in other cases the underlying gene or genes involved remain unclear. We describe a patient, a 63-year-old female, who was diagnosed with a medullary thyroid carcinoma (MTC), which was confirmed pathologically after thyroidectomy, but whose circulating calcitonin levels remained elevated after thyroidectomy with no evidence of metastatic disease. Subsequently, an entirely separate and discrete duodenal NET was identified; this was 2.8 cm in diameter and was removed at partial duodenectomy. The tumour stained immunohistochemically for calcitonin, and its removal led to persistent normalisation of the circulating calcitonin levels. There was no germline mutation of the RET oncogene. This is the first identification of a duodenal NET secreting calcitonin and also the first demonstration of a second tumour secreting calcitonin in a patient with MTC. We suggest that where calcitonin levels remain high after removal of a MTC a search for other NETs should be conducted.

Learning points

NETs are a complex and heterogeneous group of related neoplasms, and multiple tumours may occur in the same patient.

Calcitonin can be produced ectopically by several tumours outside the thyroid.

Persistently elevated calcitonin levels after removal of a MTC may not necessarily indicate persisting or metastatic disease from the tumour.

The real prevalence of calcitonin-producing NETs may be underestimated, as serum determination is only recommended in the diagnosis of pancreatic NETs.
Application of Operator-Splitting Technique in Numerical Simulation of Gas-Hydrate Reservoirs
Authors: Shahbazi A.. , Pooladi-Darvish M.. 
Published: July 2013

Summary
Modeling of hydrate reservoirs has revealed large time-scale discrepancies between the mechanisms involved. Compared with the fluid- and heat-flow terms, the time scale of the kinetics term is orders of magnitude smaller, especially when the intrinsic reaction rate is large. Previous studies have shown that simulation of hydrates may require very small timesteps to ensure convergence. Further investigations have shown that, for sharp decomposition cases in which dissociation occurs in a narrow region, nonphysical oscillation becomes a simulation issue, unless very small time-steps are chosen. A 3D numerical model incorporating heat and fluid flow with kinetics of decomposition and reformation of hydrates has been developed. In this paper, a methodology for the use of larger timesteps is proposed without loss of accuracy. The focus of this work is on the decoupling of the reaction and flow operators. The decoupling, or so-called operator splitting, allows selection of different timesteps for the different mechanisms. The success of the splitting methodology in saving computational time is demonstrated for two cases. The first case shows oscillatory solutions, and the application of operator splitting allows for an oscillation-free solution at a smaller run time. In the second case, a problem with a range of reaction constants is studied. Obtaining a stable solution without operator splitting requires adjusting the overall timestep, such that the problem with the faster reaction requires very small timesteps. The application of operator splitting in this case allows for a stable solution with much larger timesteps. The contribution of this work is developing a methodology to improve the computational-time of large-scale simulations of gas-hydrate reservoirs without loss of accuracy.
Insights into Genotype × Tillage Interaction Effects on the Grain Yield of Wheat and Maize
Authors: Herrera J. M. , Verhulst N. , Trethowan R. M. , Stamp P. , Govaerts B. 
Published: July 2013

ABSTRACTNo tillage or zero tillage (NT) is the extreme form of reduced tillage; NT with residue retention is a main component of conservation agriculture. Using a literature survey and meta‐analysis, this study aimed to (i) summarize the results of studies comparing the grain yield of wheat [Triticum aestivum L. and Triticum turgidum L. subsp. durum (Desf.) Husn. (syn. Triticum durum Desf.)] and maize (Zea mays L.) genotypes under contrasting tillage, (ii) identify sources of variation in the grain yield response of wheat and maize genotypes to tillage practices, and (iii) identify potential traits for NT breeding programs. Grain yield was compared under NT and conventional tillage (CT) for 112 wheat genotypes (44 spring, 60 winter, and eight durum wheat genotypes) across 12 locations and 24 yr and for 93 maize hybrids across six locations and 5 yr. Most of these studies showed slightly higher grain yields under CT for maize (+5%) and winter (+5%) and spring (+2%) wheat. In the few studies where selection had been conducted under NT, the effect of tillage on the grain yield was modified significantly by genotypes. Traits associated with the emergence of vigorous seedlings and resistance to a changed spectrum of diseases increase genotype performance under NT. There is a need to evaluate genotypes developed under NT and extend the research on genotype performance under NT to locations with reduced input use and, in addition to tillage, investigate other factors that differentiate conservation agriculture from conventional practice.
Characterization of Populations of Turf‐Type Perennial Ryegrass Recurrently Selected for Superior Freezing Tolerance
Authors: Iraba Amandine , Castonguay Yves , Bertrand Annick , Floyd Donald J. , Cloutier Jean , Belzile François 
Published: July 2013

ABSTRACTPerennial ryegrass (Lolium perenne L.) is an important turfgrass species used for lawns, sports fields, and recreational areas. Insufficient tolerance to subfreezing temperatures compromises its persistence in northern climates. A recurrent selection method, entirely performed indoors, was applied to two initial genetic backgrounds to generate populations putatively more tolerant to freezing (TF populations). The objective of the present study was to assess physiological and molecular responses after four cycles of selection (TF1–TF4). Freezing tolerance and cold‐induced metabolites were monitored in plants hardened to natural variations in temperatures in fall and winter in an unheated greenhouse. Recurrent selection improved freezing tolerance expressed as the lethal temperature for 50% of the plants (LT50) and the vigor of regrowth after freezing. Significant changes in the levels of total and individual cold‐induced carbohydrates (fructans) and amino acids (glutamine and proline) in crowns of hardened plants occurred in response to selection. Both groups of metabolites showed an opposite response to selection. The observation of DNA polymorphisms and progressive genetic differentiation between the initial populations and advanced cycles of selection suggests an impact of selection on allelic composition. Recurrent selection had a positive impact on freezing tolerance of perennial ryegrass through modifications in the molecular and genetic makeup of the populations.
Alexithymia Affects Pre-Hospital Delay of Patients with Acute Myocardial Infarction: Meta-Analysis of Existing Studies
Authors: Preti Antonio , Sancassiani Federica , Cadoni Federica , Carta Mauro Giovanni 
Published: July 2013

Background:
The time between the onset of symptoms and reperfusion is a critical determinant of the clinical course of patients with acute myocardial infarction (AMI). Any delay in seeking help will affect patient’s outcome. Alexithymia can influence the information processing but also the skills to detect the signal of an ongoing AMI.

Method:
Systematic review and meta-analysis of studies investigating the role of alexithymia in pre-hospital delay after AMI. Pubmed/Medline and PsychINFO/Ovid search from 1990 until 2012.

Results:
Out of 29 studies investigating the role of psychological factors in pre-hospital delay after AMI, 3 studies specifically assessed alexithymia, involving 258 patients. All studies used the Toronto Alexithymia Scale to group patients into clusters by time to presentation after AMI. Meta-analysis of data showed that the patients with higher emotional awareness (i.e., low alexithymia) had shorter time to presentation after AMI.

Conclusions:
Preliminary evidence indicates that alexithymia may have a role in seeking help delay after AMI. Further studies are necessary to better appreciate how alexithymia influence help-seeking in patients with an evolving AMI and in what extent their ineffective behavior can be changed.
Dabigatran and Kidney Disease
Authors: Knauf Felix , Chaknos C. Michael , Berns Jeffrey S. , Perazella Mark A. 
Published: July 2013

Summary
Dabigatran is an oral direct thrombin inhibitor widely used to prevent and treat various thromboembolic complications. An advantage of this agent over other anticoagulants is that routine laboratory monitoring and related dose adjustments are considered unnecessary. A major disadvantage is the absence of a reliable means of reversing its anticoagulant effect. After U.S. Food and Drug Administration approval, recently emerged data suggest a higher bleeding risk with dabigatran, especially in the elderly. Clinicians are thus faced with caring for patients with serious bleeding events without readily available tests to measure drug levels or the anticoagulant effects of dabigatran and without effective antidotes to rapidly reverse the anticoagulant effect. On the basis of dabigatran's pharmacokinetic profile, hemodialysis and continuous renal replacement therapy have been used to remove dabigatran with the hope, still unproven, that this would rapidly reverse the anticoagulant effect and reduce bleeding in patients with normal and those with reduced kidney function. However, the best clinical approach to the patient with serious bleeding is not known, and the risks of placing a hemodialysis catheter in an anticoagulated patient can be substantial. This article reviews this issue, addressing clinical indications, drug pharmacokinetics, clinical and laboratory monitoring tests, and dialytic and nondialytic approaches to reduce bleeding in dabigatran-treated patients.
The Role of Auditors' Emotions and Moods on Audit Judgment: A Research Summary with Suggested Practice Implications
Authors: Bhattacharjee Sudip , Moreno Kimberly K. 
Published: July 2013

SUMMARY
The reality for auditors is that, during the audit process, they will experience emotional reactions, such as liking or disliking toward client personnel, or anxiety about components of tasks. Auditors also may experience different moods while conducting audits. Research reveals that an important consequence of auditors experiencing emotions and moods is that these reactions can influence their decision making. We provide a summary of the results and practice implications associated with several studies in a stream of research that has examined the impact of auditors' emotions and moods on audit judgments.
Einstein-Weyl structures on lightlike hypersurfaces
Authors: Atindogbe Cyriaque , Bérard-Bergery Lionel , Ogouyandjou Carlos 
Published: July 2013

AbstractWe study Weyl structures on lightlike hypersurfaces endowed with a conformal structure of certain type and specific screen distribution: the Weyl screen structures. We investigate various differential geometric properties of Einstein-Weyl screen structures on lightlike hypersurfaces and show that, for ambient Lorentzian space ℝ1n+2 and a totally umbilical screen foliation, there is a strong interplay with the induced (Riemannian) Weyl-structure on the leaves.