bluuebunny/crossref_metadata_2025_split huggingface dataset:
Consolidation of Sand-Clay Mixtures
Authors: Fukue M , Okusa S , Nakamura T 
Published: December 2008

Consolidation properties of bentonite-sand mixtures, as reclamation materials, were investigated in the one-dimensional consolidation test. From the relationships between the void ratio of nonclay fraction and consolidation pressure was found the existence of a threshold void ratio at which the frictional resistance becomes dominant during consolidation. The threshold value is slightly greater than the maximum void ratio of sand used for the mixtures.
A new standard, which utilizes values of clay content, dry density, and threshold void ratio, is proposed to clarify the boundary between sandy and clayey soils.
The salt infiltration into the mixtures causes a rapid settlement but greatly reduces the swelling in unloading stage. As long as the void ratio of nonclay fraction is less than the threshold value, however, the influence of salt disappears.
Consolidation Testing—A Comparative Study
Authors: Bauer GE , El-Hakim AZ 
Published: December 2008

The knowledge of the preconsolidation pressure, p′e, of an overconsolidated clay is of vital importance in the settlement analysis of structures. It has been found that the semigraphical methods to determine p′e proposed by Casagrande, Burmister, and Schmertmann are not completely satisfactory for sensitive clays. Also, the standard oedometer test is not adequate to fully describe the strain-effective stress behavior of such clays. Renewed interest in this topic by several investigators has shown that the magnitude of the preconsolidation pressure is greatly affected by the rate of loading, type of loading, specimen size, and type of testing apparatus used.
This paper reports on the results of a comparative study of consolidation behavior using two types of clays and four different testing techniques. The first series of tests was carried out on undisturbed specimens of soft Leda (Champlain Sea) clay cut from block samples and the second series was performed on prepared and consolidated kaolin specimens. For each series, four different consolidation apparatuses were used: a standard oedometer, a modified Rowe cell, an Anteus apparatus, and triaxial K0 tests. Both Leda clay and kaolin specimens were tested in parallel. Several sizes (diameters) of specimens and different loading techniques were used. Based on these test results, it was shown that the controlled gradient consolidation test using the Rowe cell with a softer membrane was the most suitable technique to establish a well-defined effective stress-strain curve. The controlled gradient test using the Anteus apparatus also gave a well-defined stress-strain relationship, but the operational procedures were found quite cumbersome. The K0-triaxial test was quite time-consuming and an elaborate recording of data was required. The results from standard oedometer tests, even using a modified loading, did not yield continuous effective stress-strain plots and p′e was difficult to determine. Also, a comparison of the coefficients of consolidation was made for the two clays and the various testing techniques employed.
An Evaluation of Fracture Analysis Methods
Authors: Newman JC 
Published: December 2008

This paper presents the results of an experimental and predictive round robin conducted by the American Society for Testing and Materials (ASTM) Task Group E24.06.02 on Application of Fracture Analysis Methods. The objective of the round robin was to verify whether fracture analysis methods currently used can or cannot predict failure loads on complex structural components containing cracks. Fracture results from tests on compact specimens were used to make these predictions. Results of fracture tests conducted on various-size compact specimens made of 7075-T651 aluminum alloy, 2024-T351 aluminum alloy, and 304 stainless steel were supplied as baseline data to 18 participants. These participants used 13 different fracture analysis methods to predict failure loads on other compact specimens, middle-crack tension (formerly center-crack tension) specimens, and structurally configured specimens. The structurally configured specimen, containing three circular holes with a crack emanating from one of the holes, was subjected to tensile loading.
The accuracy of the prediction methods was judged by the variations in the ratio of predicted-to-experimental failure loads, and the prediction methods were ranked in order of minimum standard error. The range of applicability of the prediction methods was also considered in assessing their usefulness. For 7075-T651 aluminum alloy, the best methods (predictions within ±20% of experimental failure loads) were: the effective KR-curve, the critical crack-tip-opening displacement (CTOD) criterion using a finite-element analysis, and the KR-curve with the Dugdale model. For the 2024-T351 aluminum alloy, the best methods were: the Two-Parameter Fracture Criterion (TPFC), the CTOD criterion using the finite-element analysis, the KR-curve with the Dugdale model, the Deformation Plasticity Failure Assessment Diagram (DPFAD), and the effective KR-curve with a limit-load condition. For 304 stainless steel, the best methods were: limit-load (or plastic collapse) analyses, the CTOD criterion using the finite-element analysis, the TPFC, and the DPFAD. The failure loads were unknown to all participants except the author, who used both the TPFC and the CTOD criterion (finite-element analysis).
Prediction of Stable Crack Growth and Instability Using the VR-Curve Method
Authors: Newman JC 
Published: December 2008

This paper presents a methodology for predicting stable crack growth and instability of cracked structural components from results of laboratory tests on metallic materials under plane-stress conditions. The methodology is based on the displacement (VR) at the tip of a stably tearing crack. Basically, the VR-curve method is a resistance curve approach, such as KR and JR, except that the “crack drive” is written in terms of crack-tip displacement instead of K or J. The relationship between crack-tip-opening displacement, crack length, specimen type, and tensile properties is derived from the Dugdale model for the cracked structure of interest.
This report describes the laboratory test procedure and calculations used to obtain the VR resistance curve from fracture tests of compact or of middle-crack tension (formally center-crack) specimens. The analysis procedure used to predict stable crack growth and instability of any through-the-thickness crack configuration made of the same material and thickness, and tested under the same environmental conditions, is presented. The various limitations of the present VR-curve method are given. Four example calculations and predictions are shown.
Characterization of T300/V-378A Graphite/Bismaleimide for Structural Applications
Authors: Ramkumar RL , Grimes GC , Kong SJ 
Published: December 2008

This paper discusses the potential of T300/V-378A graphite/bismaleimide for use in aircraft structures that are likely to be exposed to service temperatures in the 120 to 204°C (250 to 400°F) range. The microstructure of cured T300/V-378A laminates was examined to detect the presence of any process-induced defects; moisture absorption studies were conducted to characterize the hygroscopic behavior of the material; and its basic properties were generated through static tests on [0]16T, [90]16T, and [±45]4s laminates. These were followed by static tests on plain [0/±45/90]2s T300/V-378A specimens and specimens with unloaded (open and filled) and loaded holes. Tests were conducted under room temperature, dry (RTD) and elevated temperature, wet (ETW) conditions. Plain specimens and specimens with open holes were also subjected to constant-amplitude fatigue tests at minimum-to-maximum cyclic stress ratios (R) of 0.05 and −1.0.
Subsequently, the tolerance of [0/±45/90]4s T300/V-378 laminates to low-velocity impact damage by a hard object was evaluated by measuring impact energy levels corresponding to incipient (not necessarily visible) damage and through-penetration. Specimens from impact-damaged panels were then tested to obtain residual static compression strengths. Finally, multibay, hat-stiffened, flat shear panels were fabricated using the T300/V-378A material system, and were subjected to pure-shear static and fatigue tests under RTD and ETW conditions.
Results were compared with available data on T300/5208 and AS/3501-6 graphite/epoxy laminates to assess the relative merits of the T300/V-378A graphite/bismaleimide material system. In general, the RTD matrix-dominated response of T300/V-378A laminates is inferior to that of AS1/3501-6 laminates. But, the T300/V-378A laminates retain most of their RTD strengths under 177°CW (350°FW) (wet) conditions, where conventional epoxy-matrix materials suffer property losses that occur at the glass transition temperature. The V-378A bismaleimide material, therefore, provides a viable alternative to conventional epoxy-matrix materials, for applications in components that experience humid conditions and temperatures in the 120 to 205°C (250° to 400°F) range.
Compression Failure Mechanisms in Unidirectional Composites
Authors: Hahn HT , Williams JG 
Published: December 2008

The present paper examines compression failure mechanisms in unidirectional composites. Possible failure modes of constituent materials are summarized and analytical models for fiber microbuckling are reviewed from a unified viewpoint. Due to deficiencies in available models, a failure model based on nonlinear material properties and initial fiber curvature is proposed.
The effect of constituent properties on composite compression behavior was experimentally investigated using two different graphite fibers and four different epoxy resins. The predominant macroscopic-scale failure mode was found to be shear crippling. In a soft resin, shear crippling was in the form of buckling of fibers on a microscopic scale. However, for stiff resins, failure was characterized by the formation of a kink band. For unidirectional laminates, compressive strength, and compressive modulus to a lesser extent, were found to increase with increasing magnitude of resin modulus. The change in compressive strength with resin modulus was predicted using the proposed nonlinear model.
Effect of Laminate Thickness and Specimen Configuration on the Fracture of Laminated Composites
Authors: Harris CE , Morris DH 
Published: December 2008

The effect of laminate thickness on the fracture behavior of laminated graphite/epoxy (T300/5208) composites has been studied. The predominantly experimental research program included the study of the [0/±45/90]ns and [0/90]ns laminates with thicknesses of 8, 32, 64, 96, and 120 plies and the [0/±45]ns laminate with thickness of 6, 30, 60, 90, and 120 plies. The research concentrated on the measurement of fracture toughness utilizing the center-cracked tension, compact tension, and three-point bend specimens. The development of crack-tip damage prior to fracture was also studied.
Test results showed fracture toughness to be a function of laminate thickness. The fracture toughness of the [0/±45/90]ns and [0/90]ns centercracked laminates decreased with increasing thickness and asymptotically approached lower bound values of 1043 MPa √mm (30 ksi √in.) and 869 MPa √mm (25 ksi √in.), respectively. The fracture toughness of the [0/±45]ns center-cracked laminate increased with increasing thickness but reached an upper plateau value of 1390 MPa √mm (40 ksi √in.). The fracture toughness of all laminates was independent of crack size except the [0/90]2s laminate that split extensively. The fracture surface of all thick laminates was uniform in the interior and self-similar with the starter notch. With the exception of the [0/±45]ns laminate, the fracture toughness of the thicker laminates was relatively independent of specimen configuration.
Chemical Shrinkage and Differential Sorptions in Mixtures of Portland Cement and Blast-Furnace Slag
Authors: Mills RH 
Published: December 2008

The relationship between chemical shrinkage, expressed as volume per unit mass of anhydrous cementing material, and chemically bound water varies over a narrow range with the ratio of portland cement (PC) to blast-furnace slag (BFS). Chemical shrinkage is easily measured and affords an easily executed nondestructive measure of quality for cements made with mixtures of PC and BFS.
The difference between the pore space occupied by water and by kerosene expressed as a fraction of water-filled space is a measure of the volume proportion of hydrate material and is related to relative shrinkage and creep.
Permeability and Pore Structure of Cement Pastes Containing Fly Ash, Slag, and Silica Fume
Authors: Hooton RD 
Published: December 2008

As part of research to develop a highly durable concrete container for radioactive waste disposal in chloride and sulfate bearing granite groundwaters, a variety of cement pastes were studied. A sulfate resisting portland cement was used with various replacement levels of Class F fly ash and pelletized blast furnace slag at a water to solids ratio (W/S) = 0.36. Blends with fly ash, slag, and silica fume were also combined with a super water reducer at W/S = 0.25. Results are presented for strength development, permeability to water, and pore size distribution after 7, 28, 91, and 182 days moist curing. As a direct measure of durability, after 91 days moist curing, paste prisms were immersed in both de-ionized water and a synthetic chloride and sulfate bearing groundwater at 70°C.
While all three supplementary cementing materials (mineral admixtures) reduced ultimate permeabilities, silica fume was more effective in reducing permeability at early ages. Silica fume was also the most effective in reducing calcium hydroxide contents of the pastes while slag was the least effective; only reducing calcium hydroxide levels by dilution of the portland cement. From preliminary analysis, there does not appear to be a way of accurately predicting permeability from porosity or pore size parameters alone.
Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres: Second Volume
Authors: Benning MA 
Published: December 2008

Description
A source book on a subject not widely addressed in the available literature. Builds upon ASTM STP 812 and examines the design and operation of oxygen systems, aspects of the ignition of materials – both metallic and nonmetallic, flammability of metals in pure and dilute oxygen, and cleanliness and contamination.
Enemy Combatants Versus Enemy Criminal Law: An Introduction to the European Debate Regarding Enemy Criminal Law and Its Relevance to the Anglo-American Discussion on the Legal Status of Unlawful Enemy Combatants
Authors: Díez Carlos Gómez-Jara 
Published: December 2008

At the beginning of the twenty-first century two legal concepts linking citizen/enemy status with criminal law have provoked heated discussion both in Europe and in the United States. The American concept, i.e., Enemy Combatants, has been basically developed by the U.S. Supreme Court and more recently by the Bush administration. The European term, Feindstrafrecht/Enemy Criminal Law, has been fundamentally coined and explained by leading German academic Professor Günther Jakobs.
Though born and raised by different parents, the two concepts have numerous aspects in common, or at least this will be argued throughout the paper. The most important common ground is that both concepts, with similar terminology, try to address the problem of what to do with individuals who are viewed as sources of extreme dangerousness. Put differently, they both tackle the question of whether citizenship-in a broad sense-concedes certain rights but imposes a fundamental duty: to have a minimum of law-abiding behavior. If the duty is not fulfilled, then the rights are not acknowledged and the individual is treated as an enemy, not as a citizen.
The underlying reasoning oozes social contract theory. This is not by chance, as great philosophers (Rousseau, Fichte, Hobbes, Kant) have employed similar arguments that are briefly sketched in the essay. There are also references to the legal theory behind the scenes predicating that in order for legal constructions to exist (rights, the State), they need to be followed by most people. Hence such a duty to comply, in general terms, with the law is imposed upon all persons. If not, law would be just daydreaming.
Strong and consistent as all these arguments sound, the basic problem with this type of reasoning is that it is hard for the legal system to follow without entering into self-contradiction. In this light, criticism will be brought by one of the most prominent social theories of the time, i.e., systems theory, arguing that law-abiding behavior is a precondition for legal institutions to exist, yes, but it cannot be secured by law itself. It is a precondition that has to be presupposed by the legal system. Moreover, using this kind of necessity rule, i.e., the State and the Law need to secure the preconditions of their own existence (self-preservation), entails a diabolic logic as it may lead to the destruction of the system itself. To this extent, self-preservation against external threats (terrorist attacks) and internal threats (curtailment of civil liberties) seems equally important. The essay finishes with some proposals for resolving this delicate matter, trying to reflect a keen sense of balance and forward-looking thinking.
Distribution of Lindane in Water, Sediment, and Fish from the Warri River of the Niger Delta, Nigeria
Authors: Ezemonye Lawrence , Ikpesu Thomas , Tongo Isioma 
Published: December 2008

Distribution of Lindane in Water, Sediment, and Fish from the Warri River of the Niger Delta, NigeriaThis paper is the first attempt to quantify the levels and the distribution pattern of lindane in the surface water, sediment and fish (Chrysichthys furcatus and Tilapia zilli). The samples were collected from three stations (Ovwian, Ekakpamre, and Ovu) of the Warri River in the western Niger Delta of Nigeria in 2006: during the dry (January-April) and wet seasons (May-August). The analysis included a total of 96 samples made up of 24 samples each for water, sediment, and fish. The pesticide levels were analysed using high performance liquid chromatography to elucidate its distribution in various environmental compartments. Residue levels in the matrices ranged from below the detection limit (BDL) to 1.37μg L-1 in water, BDL to 12.66 μg g-1 dry weight (dw) in sediment, BDL to 16.67 μg g-1dw in Chrysichthys furcatus, and BDL to 0.15 μg g-1dw in Tilapia zilli. The observed values were above the ecological benchmarks (0.01 μg L-1) recommended by the Nigerian Environmental Protection Agency and European Union. They were also relatively higher than in previous studies on the Nigerian environment, which calls for regular monitoring of the Niger Delta water bodies.
Atom as a “dressed” nucleus
Authors: Kalitvianski Vladimir 
Published: December 2008

Abstract
We show that the electrostatic potential of an atomic nucleus “seen” by a fast charged projectile at short distances is quantum mechanically smeared due to nucleus motion around the atomic center of inertia. For example, the size of the “positive charge cloud” in the Hydrogen ground state is much larger than the proper proton size. For target atoms in excited initial states, the effect is even larger. The elastic scattering at large angles is generally weaker than the Rutherford scattering since the effective potential at short distances is softer than the Colombian one due to a natural “cutoff”. In addition, the large-angle scattering leads to target atom excitations due to pushing the nucleus (⇒ inelastic processes). The Rutherford cross section is in fact inclusive rather than elastic. These results are analogous to those from QED. Non-relativistic atomic calculations are presented. The difference and the value of these calculations arise from nonperturbatively (exact) nucleus “dressing” that immediately leads to correct physical results and to significant technical simplifications. In these respects a nucleus bound in an atom is a simple but rather realistic model of a “dressed” charge in the QFT. This idea is briefly demonstrated on a real electron model (electronium) which is free from infinities.
The Current State of Musculoskeletal Clinical Skills Teaching for Preclerkship Medical Students
Authors: OSWALD ANNA E. , BELL MARY J. , SNELL LINDA , WISEMAN JEFFREY 
Published: December 2008

ObjectiveMusculoskeletal (MSK) complaints have high prevalence in primary care practice (12%–20% of visits), yet many trainees and physicians identify themselves as weak in MSK physical examination (PE) skills. As recruitment to MSK specialties lags behind retirement rates, there is a short-age of physicians able to effectively teach this subject. We investigated current practices of Canadian undergraduate medical programs regarding the nature, amount, and source of preclerkship MSK PE clinical skills teaching; and documented the frequency and extent that Patient Partners® in Arthritis (PP®IA) are used in this educational setting.MethodsA 2-page self-administered electronic questionnaire combining open- and close-ended questions was developed and piloted. It was distributed by e-mail to all Canadian undergraduate associate-deans and to 16/17 undergraduate MSK course organizers.ResultsSupervised practice in small groups and the PP®IA are the most prevalent teaching methods. Objective structured clinical examinations are the most prevalent evaluation methods. The average number of hours devoted to teaching these skills is very small compared to the prevalence of MSK complaints in the population. Canadian schools’ preclerkship MSK PE clinical skills teaching is heavily dependent on the contributions of non-MSK specialists.ConclusionThe weak link in the Canadian MSK PE educational cycle appears to be the amount of time available for students’ deliberate practice with expert feedback. There is a need for methods to evaluate and further develop MSK PE teaching by non-MSK specialists. This and increased use of PP®IA at the preclerkship level may provide students more time for practice with feedback.
Electrocardiographic Findings in Psoriatic Arthritis: A Case-Controlled Study
Authors: FELD JOY , WEISS GIORA , ROSNER ITZHAK , ROZENBAUM MICHAEL , LAOR ARIE , RIMAR DORON , EDER LIHI , BITTERMAN HAIM , ZISMAN DEVY 
Published: December 2008

ObjectiveWe assessed cardiac conduction properties in patients with psoriatic arthritis (PsA).MethodsElectrocardiogram (ECG) scans of 92 patients with PsA were compared to 92 age and sex matched nonpsoriatic, nonarthritic patients from general practice serving as controls.ResultsPR interval was found to be significantly longer in the PsA group compared to controls, 159.6 ± 21 ms versus 151.3 ± 26 ms, respectively (p = 0.021). No statistical difference was found with respect to the QRS interval or other atrial or ventricular conduction disturbances studied. No correlation was found between the PR interval and disease duration or PsA subtype. The use of non-steroidal antiinflammatory drugs did not affect the PR interval. Methotrexate was not found to influence the PR interval, compared to other disease modifying antirheumatic drugs. Two PsA patients (2.1%) had a PR interval > 0.2 ms. Their prolonged PR interval could not be explained by medication use. The abnormal prolongation of the PR interval was asymptomatic, requiring no additional intervention. No patient had complete heart block.ConclusionOur study may suggest subtle involvement of the atrioventricular node in patients with PsA.