bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tension stiffening in transverse sections of circular-voided reinforced concrete slabs
Authors: Oduyemi T. O. S. , Clark L. A. 
Published: October 2009

Synopsis For an accurate assessment of the service load response of a concrete structure, the tension stiffening effect of concrete between major cracks needs to be taken into account. Previous studies of tension stiffening have been mainly concerned with solid beams and slabs. At present there is no generally accepted method for determining tension stiffening in voided slabs. This paper presents the results of tests on fifteen 1: 3·33 scale model transverse strips of practical reinforced concrete voided slabs. A method of predicting tension stiffening in transverse strips of voided slabs is presented, and a simplified procedure suitable for design purposes is proposed.
Prediction of crack widths in circular-voided reintorced concrete slabs subjected transverse to bending
Authors: Oduyemi T. O. S. , Clark L. A. 
Published: October 2009

Synopsis When concrete slabs containing longitudinal circular voids are subjected to transverse bending, a complex stress pattern occurs and the first cracks appear at the inverts of the voids. If sufficient reinforcement is provided in the tension flange, subsequent outer-face cracks appear at about a quarter of the void diameter each side of the first cracks. Previous studies of the cracking behaviour of transverse strips of voided slabs have shown that, due to the predetermined and highly-concentrated type of cracking, very wide and uncontrollable cracks sometimes occur. Since the equations which are currently used for predicting crack widths in solid slabs do not take into consideration the effect of the presence of voids on the crack formation process, a new method is needed for predicting the widths of cracks in voided slabs subjected to transverse bending. This paper presents a suitable method which gives reasonable predictions of the widths of such cracks. The method was evolved from both theoretical and experimental investigations involving tests on fourteen 1: 3·33 scale model transverse strips of practical voided slabs. Consideration is also given to the amounts of reinforcement which are needed (a) to prevent premature yielding of the steel, (b) to achieve a controlled crack pattern, and (c) to limit the widths of the cracks to acceptable levels as specified in BS 5400, the British Standard Code of Practice for concrete bridges.
Near-surface characteristics of concrete: assessment and development of in situ test methods
Authors: Dhir R. K. , Hewlett P. C. , Chan Y. N. 
Published: October 2009

Synopsis The British Standard initial surface absorption test (ISAT), Figg hypodermic methods (air and water), and a new test, the covercrete absorption test (CAT), have been used to study the permeation properties of the near-surface of concrete. The test methods are critically appraised. It is shown that the moisture condition of the concrete can greatly alter the results obtained. Data on the surface quality of concrete and its dependence on mix proportions and degree of moist curing are presented.
Investigation of the mechanism of shear failure of reinforced concrete beams
Authors: Chana P. S. 
Published: October 2009

Synopsis The mechanism of shear failure in reinforced concrete beams was studied. Crackwidths at critical locations in the shear span were monitored continuously by means of a high speed tape recorder in conjunction with electrical demountable strain transducers and related to the load history approaching failure. It is shown that beam failure is preceded by splitting at the level of the steel; this is identijied to be the primary cause ofshear failure for slender beams. Further tests are described on beams where this splitting is prevented by the presence of links. In these tests, a diflerent failure mechanism isobserved with SignlJcant increase in shear capacity. The implications of theseJindings ondesign methods in codes of practice are discussed.
Decomposition of a concrete floor and ignition of gaseous products due to spillage of molten aluminium
Authors: Shayan A. , Gibbs P , Martin K. G. 
Published: October 2009

Synopsis Spillage of molten aluminium onto the concrete floor of the Bone Island Aluminium Smelters in Queensland, Australia has caused several serious fires which have decomposed the floor and sometimes partially melted the pot assembly, resulting in enormous repair costs and delays in production. A study of the concrete showed that it was made with limestone aggregate. The molten aluminium at about 1050°C formed ponds about 2 m in diameter and 200 mm deep. It decomposed the limestone and produced CO2 gas which was reduced by the molten aluminium to CO gas which ignited. This strongly exothermic reaction produced further heat and melted the reinforcing bars in the concrete. The moisture in the concrete formed steam and agitated the system so that the molten metal was more efectively in contact with the concrete and caused further decomposition of the limestone. Laboratory experiments with limestone and non-calcareous aggregates, and concretes made with them, showed that the limestone was the primary cause of the fires. Based on computer modelling, it was determined that a concrete capping of 75 mm thickness made with non-calcareous aggregate and applied on the existing floor would protect it from decomposition and ignition.
Microstructural studies of Jurassic limestone aggregates with reference to durability in concrete
Authors: Collins R. J. 
Published: October 2009

Synopsis The pore structure of 15 samples of porous limestone has been studied by mercury intrusion porosimetry and optical microscopy. This followed laboratory freeze/ thaw tests in which concretes made with porous lime- stone coarse aggregate performed better on average than control concretes made with low porosity coarse aggregate. Good durability was correlated with relatively low porosity (less than 0·05ml/g) in pores less than 0·2pm nominal radius, together with an adequate volume of pores larger than 0·2pm radius. More of these larger pores are required in weaker aggregates which are less able to withstand internal freezing pressures. These criteria appear to be appropriate only to climates similar to the UK and not to continental or arid climates.
A repeated drop-weight impact testing apparatus for concrete
Authors: Barr B. , Baghli A. 
Published: October 2009

Synopsis The development and use of a versatile instrumented repeated drop-weight impact testing apparatus for concrete is described. Impact resistance is determined in terms of the number of blows required to completely fracture steel-fibre-reinforced concrete test specimens. Parameters investigated included specimen geometry, notch depth, steel-fibre concentration, and mass and height of the dropped weight. Coefficients of variation of 15–20% were measured. Two load cells were used to monitor the impacting loads and the corresponding loads at the support, from which load-time graphs were plotted. Peak loads developed, impulsive loads and the duration of the impact event could then be measured. Good reproducibility was observed from the peak load results. The graphs also showed that larger masses were more efficient than lighter masses in producing impact failure in the test specimens.
Snap-back and hyperstrength in lightly reinforced concrete beams
Authors: Carpinteri Alberto 
Published: October 2009

Synopsis The phenomena of hyperstrength and snap-back in lightly reinforced concrete beams are interpreted according to the concepts fracture mechanics. The tensile strength and toughness of concrete, usually disregarded, are so high in some cases that the maximum bending moment overcomes the bending moment of limit design (hyperstrength). The drop in load capacity hides a virtual sofiening load-deflection branch with positive slope (snap-back), which can be detected if the loading process is controlled through the crack width.
Early-age strain and temperature measurements in concrete tank walls
Authors: Anson M. , Rowlinson P. M. 
Published: October 2009

Synopsis The paper reports measurements of temperatures induced by heat of hydration in 12 reinforced concrete walls during construction. In-plane movements at early age are also given for one of the walls in which 27 vibrating wire strain gauges were installed. In-plane strains are deduced and estimates made of the restraint to free in-plane movement of the concrete. The concept of a restraint,factor is already applied in design for crack control. Restraint to free movement us cooling of the new concrete takes place, is provided externally by previously cast elements such as a all foundation, combined with internal effects, which arise from the fact that peak temperatures vary considerably between different parts of the wall itself. The experimental strain results are compared with the results of a finite element analysis in which base and wall panel are treated as an integral structural unit. Comparisons are also made with codes of practice and other guidance documents.
Mechanisms of the influence of externally supplied NaCl on the expansion of mortars containing reactive aggregate
Authors: Kawamura M. , Takeuchi K. , Sugiyama A 
Published: October 2009

Translation from Proceedings of JSCE, 25, No. 502, 1994 This study aims at revealing the mechanisms of the influence of NaCl externally supplied on the expansion of mortars due to the alkali–silica reaction. In reactive aggregate-bearing mortars with relatively low alkali contents, the promotion of their expansions in 1 M NaCl solution at 38°C was caused by a rise of OH− ion concentration in the pore solution. The increase in OH− ion concentration in the pore solution in mortars was responsible for the intrusion of Cl− ions into mortars containing a reactive aggregate. In reactive aggregate-bearing mortars with a relatively large amount of added NaOH, at least a part of unusually large expansions of the mortars was caused by the delayed formation of ettringite during the immersion in NaCl solution.
Analytic wave functions and energies for two-dimensional $$
\mathcal{P}\mathcal{T}
$$-symmetric quartic potentials
Authors: Tichý Vladimír , Skála Lubomír 
Published: October 2009

Abstract
Analytic wave functions and the corresponding energies for a class of the $$
\mathcal{P}\mathcal{T}
$$-symmetric two-dimensional quartic potentials are found. The general form of the solutions is discussed.
Dielectric properties of Ba3Sr2DyTi3V7O30 ceramics
Authors: Sahoo Priyadarshini , Panigrahi Anuradha , Patri Sunanda , Choudhary Rasm 
Published: October 2009

Abstract
A polycrystalline sample, Ba3Sr2DyTi3V7O30, with tungsten bronze structure was prepared by a mixed-oxide method at high temperature (950°C). Preliminary structural analysis of the compound showed an orthorhombic crystal structure at room temperature. Surface morphology of the compound was studied by scanning electron microscopy. The dielectric anomaly at 321°C may be attributed to the ferro-paraelectric phase transitions. This was also confirmed from the appearance of a hysteresis loop. The nature of variation of the ac conductivity and value of activation energy at different temperature regions, suggest that the conduction process is of mixed-type (i.e., ionic-polaronic and space charge generated from the oxygen ion vacancies).
Magnetism, entropy, and the first nano-machines
Authors: Mitra-Delmotte Gargi , Mitra Asoke 
Published: October 2009

Abstract
The efficiency of bio-molecular motors stems from reversible interactions ∼ k
B
T; weak bonds stabilizing intermediate states (enabling direct conversion of chemical into mechanical energy). For their (unknown) origins, we suggest that a magnetically structured phase (MSP) formed via accretion of superparamagnetic particles (S-PPs) during serpentinization (including magnetite formation) of igneous rocks comprising the Hadean Ocean floor, had hosted motor-like diffusion of ligand-bound S-PPs through its ‘template’-layers. Ramifications range from optical activity to quantum coherence. A gentle flux gradient offers both detailed-balance breaking non-equilibrium and asymmetry to a magnetic dipole, undergoing infinitesimal spin-alignment changes. Periodic perturbation of this background by local H-fields of templatepartners can lead to periodic high and low-template affinity states, due to the dipole’s magnetic degree of freedom. An accompanying magnetocaloric effect allows interchange between system-entropy and bath temperature. We speculate on a magnetic reproducer in a setting close to the submarine hydrothermal mound-scenario of Russell and coworkers that could evolve bio-ratchets.
Transportation of megawatt millijoule laser pulses via optical fibers?
Authors: Tauer Johannes , Kofler Heinrich , Schwarz Elisabeth , Wintner Ernst 
Published: October 2009

Abstract
Laser ignition is considered to be one of the most promising future concepts for internal combustion engines. It combines the legally required reduction of pollutant emissions and higher engine efficiencies. The igniting plasma is generated by a focused pulsed laser beam. Having pulse durations of a few nanoseconds, the pulse energy E
p for reliable ignition amounts to the order of 10 mJ. Different methods of laser ignition with an emphasis on fiber-based systems will be discussed and evaluated.
Bioactivity guided cytotoxic activity of Clitoria ternatea utilizing brine shrimp lethality bioassay
Authors: Rahman AKM Shahidur , Arslan Oqna; , Saha Rama , Talukder Nirupama , Khaleque SMA , Ali Husne Ara 
Published: October 2009

The crude methanol extract of leaves, seeds and stem-bark of Clitoria ternatea demonstrated a significant cytotoxic activity in a brine shrimp lethality bioassay test. The LC50 values of the crude methanol extract of leaves, seeds and stem-bark were found to be 25.82, 110.92, 179.89 μgm/ml respectively Among them crude methanol extract of leaves (25.82 μgm/ml) and methanol fraction of leaves (22.28 μgm/ml) showed a very promising cytotoxic activity. Further studies have been suggested to discover a novel bioactive compound from methanol fraction of leaves of Clitoria ternatea. DOI: 10.3329/bjpp.v22i1.3564Bangladesh J Physiol Pharmacol 2006; 22(1/2) : 18-21
CD153 in Rheumatoid Arthritis: Detection of a Soluble Form in Serum and Synovial Fluid, and Expression by Mast Cells in the Rheumatic Synovium
Authors: CARVALHO RICARDO F.S. , ULFGREN ANN-KRISTIN , ENGSTRÖM MARIANNE , KLINT ERIK af , NILSSON GUNNAR 
Published: October 2009

Objective.A CD30-CD153 mast cell axis has been described in skin inflammations and Hodgkin’s lymphoma. We investigated if a soluble form of CD153 is present in the serum and synovial fluid (SF) of patients with rheumatoid arthritis (RA), and determined whether mast cells express CD153 in the synovium of these patients.Methods.Soluble forms of CD30 and CD153 were quantified in serum and SF of patients with RA by ELISA. Consecutive sections of synovial biopsies from 12 patients were stained against tryptase (mast-cell marker), CD30, and CD153.Results.Elevated concentrations of the soluble form of CD153 were found in serum from 14/15 RA patients. In the SF, 11/20 patients had detectable levels of soluble CD153. CD30 and CD153 were expressed in all biopsies that were studied. Mast cells were present in all the synovial biopsies, and expressed CD153 in one-third of the cases.Conclusion.We observed that CD153 was expressed in the synovium of patients with RA and we were able to correlate the serum levels of soluble CD153 with SF levels in the same patients. Because CD30 can activate mast cells to release chemokines without degranulation, our finding that mast cells express CD153 in RA synovium raises the possibility that a CD30-CD153 axis may contribute to the activation of synovial mast cells in the absence of degranulation.
Influence of an Educational Seminar on Use of Disease Activity Measurements by Rheumatologists in Treatment of Rheumatoid Arthritis
Authors: HAMBURGER MAX I. , HAMBURGER FRAN H. , BERGMAN J. MARTIN , EPSTEIN ALAN , BROWN ALAN 
Published: October 2009

Objective.To determine the variables underlying clinical decisions made by rheumatologists when treating patients with rheumatoid arthritis (RA), and to determine the effect of an educational seminar on the use of quantitative disease activity measurements in clinical practice in this population of physicians.Methods.Practicing rheumatologists were surveyed on the variables affecting their clinical management of patients with RA by questionnaire. Physicians were divided into 2 groups: the first comprised attenders (Group A) to an educational seminar in the use of the quantitative disease activity measurements in patient management, while the second group comprised nonattenders (Group NA). Both groups were surveyed on their practice behavior before (Survey 1) and 2 to 3 months after (Survey 2) the seminar.Results.Fifty-two rheumatologists in clinical practice from across the US completed and returned 364 surveys. A significantly greater number of rheumatologists in Group A reported use of disease activity measures following the training seminar (Survey 2), compared to their use pre-meeting and compared to Group NA (p < 0.0001).Conclusion.Our results support employment of an educational seminar on the use of disease activity measurements to increase the use of these quantitative measures in rheumatologic practice.
Poor Outcomes After Acute Myocardial Infarction in Systemic Lupus Erythematosus
Authors: SHAH MANSI A. , SHAH AMBER M. , KRISHNAN ESWAR 
Published: October 2009

Objective.Systemic lupus erythematosus (SLE) is associated with higher risk for acute myocardial infarction (MI); but the post-infarction outcomes among these patients are unknown. Our objective was to compare post-acute MI outcomes in patients with SLE to those with diabetes mellitus (DM) and those with neither condition.Methods.We analyzed the risk for prolonged hospitalization and in-hospital mortality following acute MI in the 1993–2002 US Nationwide Inpatient Sample. We used logistic regression to calculate odds ratios (OR) for prolonged hospitalization and Cox proportional hazards regression to calculate hazard ratios (HR) for in-hospital mortality with and without adjustments for age, sex, race/ethnicity, socioeconomic status, and presence of congestive heart failure.Results.For the SLE (n = 2192), DM (n = 236,016), SLE/DM (n = 474), and control (n = 667,956) groups, the in-hospital mortality rates were 8.3%, 6.2%, 5.7%, and 4.7%, respectively. In multivariable regression models, all 3 disease groups had higher adverse outcome risk compared to control. The OR for prolonged hospitalization was higher for those with SLE (OR 1.48, 95% CI 1.32–1.79) compared to those with DM (OR 1.30, 95% CI 1.28–1.32). A similar pattern was observed for hazard ratios for in-hospital mortality as well (SLE, HR 1.65, 95% CI 1.33–2.04; DM, HR 1.11, 95% CI 1.07–1.14).Conclusion.SLE, like DM, increases risk of poor outcomes after acute MI. These patients need to be triaged appropriately for aggressive care.
The Natural History of Disability and Its Determinants in Adults with Lower Limb Musculoskeletal Pain
Authors: AYIS SALMA , DIEPPE PAUL 
Published: October 2009

Objective.To investigate determinants of deterioration or improvement in disability in people with chronic hip and knee pain.Methods.We analyzed data from the Somerset and Avon Survey of Health, a longitudinal, community-based cohort study containing data collected in 1994–95 and again in 2002–03. The Medical Outcomes Study Short-Form 36 was completed by subjects at both timepoints, and used to categorize people as disabled or not. Baseline data were used to explore possible determinants of change in functional status over the 8-year time period. Adjusted odds ratios (OR) were derived from a multivariate, multinomial logistic model.Results.Data were available on 1072 subjects, all of whom reported chronic hip and/or knee pain at baseline. At baseline, 56.8% of women and 42.0% of men were disabled. Of 545 people with disabilities at baseline, 107 (19.6%) reported no disability at followup; of 527 with no disability at baseline, 177 (33.6%) became disabled. The development of disability was significantly associated with older age (OR 2.1), living in the most deprived areas (2.4), the presence of 3 or more comorbidities (3.6), more problems with physical function at baseline (2.0), and more severe pain (2.4). The determinants of improvement mirrored those of deterioration. The data suggest a “threshold effect” at which recovery becomes unlikely.Conclusion.Of people presenting with hip or knee pain, healthcare professionals should be most concerned about those who are older, of lower socioeconomic status, with comorbidities, and who have more severe pain. Much longstanding disability might be preventable.
Abnormalities in the Regulators of Angiogenesis in Patients with Scleroderma
Authors: HUMMERS LAURA K. , HALL AMY , WIGLEY FREDRICK M. , SIMONS MICHAEL 
Published: October 2009

Objective.To determine plasma levels of regulators of angiogenesis in patients with scleroderma and to correlate those levels with manifestations of scleroderma-related vascular disease.Methods.Plasma levels of vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), fibroblast growth factor-2 (FGF-2), matrix metalloproteinase-9 (MMP-9), endostatin, pro-MMP-1, hepatocyte growth factor (HGF), placental growth factor (PlGF), and FGF-4 were examined by ELISA in a cross-sectional study of 113 patients with scleroderma and 27 healthy controls. Simple and multivariate regression models were used to look for associations between factor levels and clinical disease characteristics.Results.There were marked differences in the levels of pro-angiogenic growth factors between patients with scleroderma and controls, with significant elevations of VEGF, PDGF, FGF-2, and PlGF among patients with scleroderma (p < 0.0001). Levels of MMP were also higher in scleroderma patients compared to controls (MMP-9 and pro-MMP-1) (p < 0.0001). Levels of the pro-angiogenic and anti-fibrotic factor, HGF, were noted to be lower in patients with scleroderma, but had a positive correlation with right ventricular systolic pressure (RVSP) as measured by echocardiogram (p < 0.0001) and the Raynaud Severity Score (p = 0.05). Endostatin (an anti-angiogenic factor) was notably higher in patients with scleroderma (p < 0.0001) and also correlated positively with RVSP (p = 0.023).Conclusion.These results demonstrate striking abnormalities in the circulating regulators of angiogenesis in patients with scleroderma. The levels of some factors correlate with measures of vascular disease among patients with scleroderma. Dysregulated angiogenesis may play a role in the development of scleroderma vascular disease.