Adaptable Strut-and-Tie Model for Design and Verification of Four-Pile Caps

A large percentage of pile caps support only one column, and the pile caps in turn are supported by only a few piles. These are typically short and deep members with overall span-depth ratios of less than 1.5. Codes of practice do not provide uniform treatment for the design of these types of pile caps. These members have traditionally been designed as beams spanning between piles with the depth selected to avoid shear failures and the amount of longitudinal reinforcement selected to provide sufficient flexural capacity as calculated by the engineering beam theory. More recently, the strut-and-tie method has been used for the design of pile caps (disturbed or D-region) in which the load path is envisaged to be a three-dimensional truss, with compressive forces being supported by concrete compressive struts between the column and piles and tensile forces being carried by reinforcing steel located between piles. Both of these models have not provided uniform factors of safety against failure or been able to predict whether failure will occur by flexure (ductile mode) or shear (fragile mode). In this paper, an analytical model based on the strut-and-tie approach is presented. The proposed model has been calibrated using an extensive experimental database of pile caps subjected to compression and evaluated analytically for more complex loading conditions. It has been proven to be applicable across a broad range of test data and can predict the failures modes, cracking, yielding, and failure loads of four-pile caps with reasonable accuracy.

Reviewed evidence about the safety of the daily use of alcohol-based mouthrinses

Current scientific knowledge provides clear evidence that alcohol-based mouthwashes can be beneficial in a daily oral health routine, including dental hygiene and plaque control. Several issues are worth discussing, in spite of the wealth of supporting evidence. Despite some undesirable effects to some people, like burning sensation, and some contraindications, like the use by infants, alcohol addicts and patients with mucosal injuries, there is no reason to avoid the use of alcohol-containing mouthwashes as long as they are used following proper guidance by dental professionals and the manufacturers' instructions. The alleged correlation between oral cancer and alcohol-based mouthrinses presents so little, weak, inconsistent and even contradictory evidence in the literature that any kind of risk warning to patients would be uncalled for. Antimicrobial mouthrinses are safe and effective in reducing plaque and gingivitis, and should be part of a comprehensive oral health care regimen that includes brushing, flossing and rinsing to prevent or minimize periodontal disease.

Microbiological indicators for the assessment of performance in the hazard analysis and critical control points (HACCP) system in meat lasagna production

The HACCP system is being increasingly used to ensure food safety. This study investigated the validation of the control measures technique in order to establish performance indicators of this HACCP system in the manufacturing process of Lasagna Bolognese (meat lasagna). Samples were collected along the manufacturing process as a whole, before and after the CCPs. The following microorganism s indicator (MIs) was assessed: total mesophile and faecal coliform counts. The same MIs were analyzed in the final product, as well as, the microbiological standards required by the current legislation. A significant reduction in the total mesophile count was observed after cooking (p < 0.001). After storage, there was a numerical, however non-significant change in the MI count. Faecal coliform counts were also significantly reduced (p < 0.001) after cooking. We were able to demonstrate that the HACCP system allowed us to meet the standards set by both, the company and the Brazilian regulations, proved by the reduction in the established indicators

Safety Assessment of Potentially Inappropriate Medications (PIM) use in Older People and the Factors Associated with Hospital Admission

Purpose: Potentially Inappropriate Medications (PIM) use in elderly people may be responsible for the development of Adverse Drug Reaction (ADR) which, when severe, leads to hospital admissions. Objectives: to estimate the prevalence of elderly who had used PIM before being admitted to hospital and to identify the risk factors and the hospitalizations related to ADR arising from PIM. Methods: A descriptive and cross-sectional study was performed in the internal medicine ward of a teaching hospital (Brazil), in 2008. With the aid of a validated form, patients aged >= 60 years, with length of hospital stay >= 24 hours, were interviewed about drugs taken prior to the hospital admission and the complaints/reasons for hospitalization. Results: 19.1% (59/308) of older patients had taken PIM before hospital admission and in 4.9%; there were a causal relation between the PIM taken and the complaint reported. PIM responsible for admissions were: amiodarone, amitriptyline, cimetidine, clonidine, diazepam, digoxin, estrogen, fluoxetine, lorazepam, short-acting nifedipine and propranolol. 47.0% of the clinical manifestations of PIM-related ADR were: dizziness, fatigue, digoxin toxicity and erythema. Only polypharmacy was detected as a risk factor for the occurrence of ADR of PIM (p = 0.02). Conclusion: PIM use in elderly people is not a risk factor for ADR-related hospital admission. Probably, severe ADR, which lead to hospitalizations of older people, can be explained by idiosyncratic response or the predisposition of these patients to develop adverse drug events, whether or not drugs are classed as PIM.

Threat of Dengue to Blood Safety in Dengue-Endemic Countries

Dengue, the most common arbovirus infection globally, is transmitted by mosquito vectors. Healthcare-related transmission, including transmission by blood products, has been documented, although the frequency of these occurrences is unknown. Dengue is endemic to Singapore, a city-state in Asia. Using mathematical modeling, we estimated the risk for dengue-infected blood transfusions in Singapore in 2005 to be 1.625-6/10,000 blood transfusions, assuming a ratio of asymptomatic to symptomatic infections of 2:1 to 10:1. However, the level of viremia required to cause clinical dengue cases is person-dependent and unknown. Further studies are needed to establish the magnitude of the threat that dengue poses to blood safety in countries where it is endemic. It will then be possible to assess whether screening is feasible and to identify approaches that are most cost-effective on the basis of characteristics of local populations and seasonality of dengue.

Determination of the minimum value of the safety factor from geodesic Alfven eigenmodes in Joint European Torus

An analysis of the experimental conditions under which low-frequency (70-150 kHz) Alfven eigertmodes (AE) are excited during the monster sawtooth in Joint European Torus [F Romanelli et al, Proceedings of the 22nd IAEA Fusion Energy Conference, Geneva, Switzerland, 2008] is presented for the specific case of a discharge with ion cyclotron heating (5 MW) Using a simplified AE model for modes excited at the Alfven wave continuum maximum with geodesic corrections taken into account, the temporal evolution of the value of the safety factor q(0) at the magnetic axis is determined We describe a new scheme to determine the time variation of q(0) that works under conditions in which other standard diagnostics, such as the motional Stark effect do not give reliable results such as during a monster sawtooth [doi 10 1063/1 3494212]

Efficacy and safety of concurrent training in systemic sclerosis

Pinto, ALS, Oliveira, NC, Gualano, B, Christmann, RB, Painelli, VS, Artioli, GG, Prado, DML, and Lima, FR. Efficacy and safety of concurrent training in systemic sclerosis. J Strength Cond Res 25(5): 1423-1428, 2011-The optimal training model for patients with systemic sclerosis (SSc) is unknown. In this study, we aimed to investigate the effects of a 12-week combined resistance and aerobic training program (concurrent training) in SSc patients. Eleven patients with no evidence of pulmonary involvement were recruited for the exercise program. Lower and upper limb dynamic strengths (assessed by 1 repetition maximum [1RM] of a leg press and bench press, respectively), isometric strength (assessed by back pull and handgrip tests), balance and mobility (assessed by the timed up-and-go test), muscle function (assessed by the timed-stands test), Rodnan score, digital ulcers, Rayland`s phenomenon, and blood markers of muscle inflammation (creatine kinase and aldolase) were assessed at baseline and after the 12-week program. Exercise training significantly enhanced the 1RM leg press (41%) and 1RM bench press (13%) values and back pull (24%) and handgrip strength (11%). Muscle function was also improved (15%), but balance and mobility were not significantly changed. The time-to-exhaustion was increased (46.5%, p = 0.0004), the heart rate at rest condition was significantly reduced, and the workload and time of exercise at ventilatory thresholds and peak of exercise were increased. However, maximal and submaximal (V)over dotO(2) were unaltered (p > 0.05). The Rodnan score was unchanged, and muscle enzymes remained within normal levels. No change was observed in digital ulcers and Raynaud`s phenomenon. This is the first study to demonstrate that a 12-week concurrent training program is safe and substantially improves muscle strength, function, and aerobic capacity in SSc patients.

Obtaining and stability verification of superconducting phases of the Nb-Al and Nb-Sn systems by mechanical alloying and low-temperature heat treatments

The development of Nb(3)Al and Nb(3)Sn superconductors is of great interest for the applied superconductivity area. These intermetallics composites are obtained normally by heat treatment reactions at high temperature. Processes that allow formation of the superconducting phases at lower temperatures (<1000 degrees C), particularly for Nb(3)Al, are of great interest. The present work studies phase formation and stability of Nb(3)Al and Nb(3)Sn superconducting phases using mechanical alloying (high energy ball milling). Our main objective was to form composites near stoichiometry, which could be transformed into the superconducting phases using low-temperature heat treatments. High purity Nb-Sn and Nb-Al powders were mixed to generate the required superconducting phases (Nb-25at.%Sn and Nb-25at.%Al) in an argon atmosphere glove-box. After milling in a Fritsch mill, the samples were compressed in a hydraulic uniaxial press and encapsulated in evacuated quartz tubes for heat treatment. The compressed and heat treated samples were characterized using X-ray diffractometry. Microstructure and chemical analysis were accomplished using scanning electron microscopy and energy dispersive spectrometry. Nb(3)Al XRD peaks were observed after the sintering at 800 degrees C for the sample milled for 30 h. Nb(3)Sn XRD peaks could be observed even before the heat treatment. (C) 2009 Elsevier B.V. All rights reserved.

Verification of a mixed high-order accurate DNS code for laminar turbulent transition by the method of manufactured solutions

This paper presents results on a verification test of a Direct Numerical Simulation code of mixed high-order of accuracy using the method of manufactured solutions (MMS). This test is based on the formulation of an analytical solution for the Navier-Stokes equations modified by the addition of a source term. The present numerical code was aimed at simulating the temporal evolution of instability waves in a plane Poiseuille flow. The governing equations were solved in a vorticity-velocity formulation for a two-dimensional incompressible flow. The code employed two different numerical schemes. One used mixed high-order compact and non-compact finite-differences from fourth-order to sixth-order of accuracy. The other scheme used spectral methods instead of finite-difference methods for the streamwise direction, which was periodic. In the present test, particular attention was paid to the boundary conditions of the physical problem of interest. Indeed, the verification procedure using MMS can be more demanding than the often used comparison with Linear Stability Theory. That is particularly because in the latter test no attention is paid to the nonlinear terms. For the present verification test, it was possible to manufacture an analytical solution that reproduced some aspects of an instability wave in a nonlinear stage. Although the results of the verification by MMS for this mixed-order numerical scheme had to be interpreted with care, the test was very useful as it gave confidence that the code was free of programming errors. Copyright (C) 2009 John Wiley & Sons, Ltd.

Model to predict the chloride penetration in concrete with profile forming peak: verification of its precision

Chloride attack in marine environments or in structures where deicing salts are used will not always show profiles with concentrations that decrease from the external surface to the interior of the concrete. Some profiles show an increase in chloride concentrations from when a peak is formed. This type of profile must be analyzed in a different way from the traditional model of Fick`s second law to generate more precise service life models. A model for forecasting the penetration of chloride ions as a function of time for profiles having formed a peak. To confirm the efficiency of this model, it is necessary to observe the behavior of a chloride profile with peak in a specific structure over a period of time. To achieve this, two chloride profiles with different ages (22 and 27 years) were extracted from the same structure. The profile obtained from the 22-year sample was used to estimate the chloride profile at 27 years using three models: a) the traditional model using Fick`s second law and extrapolating the value of C(S)-external surface chloride concentration; b) the traditional model using Fick`s second law and shifting the x-axis to the peak depth; c) the previously proposed model. The results from these models were compared with the actual profile measured in the 27-year sample and the results were analyzed. The model was presented with good precision for this study of case, requiring to be tested with other structures in use.

A safety assessment methodology applied to CNS/ATM-based air traffic control system

In the last decades, the air traffic system has been changing to adapt itself to new social demands, mainly the safe growth of worldwide traffic capacity. Those changes are ruled by the Communication, Navigation, Surveillance/Air Traffic Management (CNS/ATM) paradigm, based on digital communication technologies (mainly satellites) as a way of improving communication, surveillance, navigation and air traffic management services. However, CNS/ATM poses new challenges and needs, mainly related to the safety assessment process. In face of these new challenges, and considering the main characteristics of the CNS/ATM, a methodology is proposed at this work by combining ""absolute"" and ""relative"" safety assessment methods adopted by the International Civil Aviation Organization (ICAO) in ICAO Doc.9689 [14], using Fluid Stochastic Petri Nets (FSPN) as the modeling formalism, and compares the safety metrics estimated from the simulation of both the proposed (in analysis) and the legacy system models. To demonstrate its usefulness, the proposed methodology was applied to the ""Automatic Dependent Surveillance-Broadcasting"" (ADS-B) based air traffic control system. As conclusions, the proposed methodology assured to assess CNS/ATM system safety properties, in which FSPN formalism provides important modeling capabilities, and discrete event simulation allowing the estimation of the desired safety metric. (C) 2011 Elsevier Ltd. All rights reserved.

Safety of a railway wheelset - derailment simulation with increasing lateral force

The motivation for this research is to make a comparison between dynamic results of a free railway wheelset derailment and safety limits. For this purpose, a numerical simulation of a wheelset derailment submitted to increasing lateral force is used to compare with the safety limit, using different criteria. A simplified wheelset model is used to simulate derailments with different adhesion conditions. The contact force components, including the longitudinal and spin effects, are identified in a steady-state condition on the verge of a derailment. The contact force ratios are used in a three-dimensional (3D) analytical formula to calculate the safety limits. Simulation results obtained with two contact methods were compared with the published results and the safety limit was identified with the two criteria. Results confirm Nadal`s conservative aspect and show that safety 3D analytical formula presents slightly higher safety limits for lower friction coefficients and smaller limits for high friction, in comparison with the simulation results with Fastsim.

Vehicle Dynamic Safety in Measured Rough Pavement

Dynamic vehicle behavior is used to identify safe traffic speed limits. The proposed methodology is based on the vehicle vertical wheel contact force response excited by measured pavement irregularities on the frequency domain. A quarter-car model is used to identify vehicle dynamic behavior. The vertical elevation of an unpaved road surface has been measured. The roughness spectral density is quantified as ISO Level C. Calculations for the vehicle inertance function were derived by using the vertical contact force transfer function weighed by the pavement spectral density roughness function in the frequency domain. The statistical contact load variation is obtained from the vehicle inertance density function integration. The vehicle safety behavior concept is based on its handling ability properties. The ability to generate tangential forces on the wheel/road contact interface is the key to vehicle handling. This ability is related to tire/pavement contact forces. A contribution to establish a traffic safety speed limit is obtained from the likelihood of the loss of driveability. The results show that at speeds faster than 25 km/h the likelihood of tire contact loss is possible when traveling on the measured road type. DOI: 10.1061/(ASCE)TE.19435436.0000216. (C) 2011 American Society of Civil Engineers.

Development of Control Systems for Safety Instrumented Systems

Safety Instrumented Systems (SIS) are designed to prevent and / or mitigate accidents, avoiding undesirable high potential risk scenarios, assuring protection of people`s health, protecting the environment and saving costs of industrial equipment. The design of these systems require formal methods for ensuring the safety requirements, but according material published in this area, has not identified a consolidated procedure to match the task. This sense, this article introduces a formal method for diagnosis and treatment of critical faults based on Bayesian network (BN) and Petri net (PN). This approach considers diagnosis and treatment for each safety instrumented function (SIF) including hazard and operability (HAZOP) study in the equipment or system under control. It also uses BN and Behavioral Petri net (BPN) for diagnoses and decision-making and the PN for the synthesis, modeling and control to be implemented by Safety Programmable Logic Controller (PLC). An application example considering the diagnosis and treatment of critical faults is presented and illustrates the methodology proposed.

Failure assessments of corroded pipelines with axial defects using stress-based criteria: Numerical studies and verification analyses

Conventional procedures used to assess the integrity of corroded piping systems with axial defects generally employ simplified failure criteria based upon a plastic collapse failure mechanism incorporating the tensile properties of the pipe material. These methods establish acceptance criteria for defects based on limited experimental data for low strength structural steels which do not necessarily address specific requirements for the high grade steels currently used. For these cases, failure assessments may be overly conservative or provide significant scatter in their predictions, which lead to unnecessary repair or replacement of in-service pipelines. Motivated by these observations, this study examines the applicability of a stress-based criterion based upon plastic instability analysis to predict the failure pressure of corroded pipelines with axial defects. A central focus is to gain additional insight into effects of defect geometry and material properties on the attainment of a local limit load to support the development of stress-based burst strength criteria. The work provides an extensive body of results which lend further support to adopt failure criteria for corroded pipelines based upon ligament instability analyses. A verification study conducted on burst testing of large-diameter pipe specimens with different defect length shows the effectiveness of a stress-based criterion using local ligament instability in burst pressure predictions, even though the adopted burst criterion exhibits a potential dependence on defect geometry and possibly on material`s strain hardening capacity. Overall, the results presented here suggests that use of stress-based criteria based upon plastic instability analysis of the defect ligament is a valid engineering tool for integrity assessments of pipelines with axial corroded defects. (C) 2008 Elsevier Ltd. All rights reserved.