Energy-Based Robustness Measure for Deteriorating Structures

2019 ◽  
Author(s):  
Marco Capalbo ◽  
Mattia Anghileri ◽  
Fabio Biondini
Keyword(s):  
Strain Energy ◽  
Performance Indicator ◽  
Weighted Average ◽  
Structural Systems ◽  
Cross Sectional ◽  
Arch Bridge ◽  
Structural Robustness ◽  
Deformation Modes ◽  
Robustness Assessment ◽  
Structural Volume

<p>An approach to robustness assessment of structural systems undergoing continuous damage is presented. Damage is described by means of a dimensionless index associated with prescribed patterns of cross-sectional deterioration and computed through a weighted average over the structural volume based on strain energy. The variation of a performance indicator associated with deformation modes and load participation factors is related to the amount of damage to obtain a dimensionless measure of structural robustness. The proposed approach is applied to structural robustness assessment of an arch bridge under continuous deterioration.</p>

Change of the critical thickness in the preferred orientation of TiN films

1995 ◽  
Vol 10 (3) ◽  
pp. 634-639 ◽  
Author(s):  
U.C. Oh ◽  
Jung Ho Je ◽  
Jeong Y. Lee
Keyword(s):  
Strain Energy ◽  
Unit Volume ◽  
Critical Thickness ◽  
Preferred Orientation ◽  
Rf Power ◽  
X Ray Diffraction ◽  
Working Pressure ◽  
Cross Sectional ◽  
Tin Films ◽  
Tin Thin Films

Recently it was observed through cross-sectional TEM that the preferred orientation of the TiN thin film was changed from (200) to (111) with thickness. In this study, the process of the change in the preferred orientation was studied near the critical thickness by x-ray diffraction, and the value of the critical thickness could be estimated. The change of the critical thickness was also investigated with the strain energy per unit volume. The strain energy could be changed by controlling the energy of the bombarding particle, i.e., by adjusting the rf power, the working pressure, and the substrate bias in sputtering. The critical thickness was decreased monotonically in all cases as the energy of the bombarding particle or the strain energy per unit volume was increased. These results surely show the dependence of the change of the preferred orientation on the strain energy in the TiN thin films.

Locking and Stability of 3D Woven Composite Reinforcements

2014 ◽  
Vol 611-612 ◽  
pp. 292-299 ◽  
Author(s):  
Sylvain Mathieu ◽  
Philippe Boisse ◽  
Nahiene Hamila ◽  
Florent Bouillon
Keyword(s):  
Finite Element ◽  
Strain Energy ◽  
Constitutive Law ◽  
Element Formulation ◽  
Woven Composite ◽  
Anisotropic Behavior ◽  
Stabilization Procedure ◽  
Bias Extension ◽  
Deformation Modes ◽  
Composite Reinforcements

3D woven composite reinforcements preforming simulations are an unavoidable step of composite part processing. The present paper deals with thick composite fabric behavior modelling and issues arising during the numerical simulation of preforming. After the description of the independent deformation modes of initially orthotropic reinforcements, a physically motivated and invariant based hyperelastic strain energy density is introduced. This constitutive law is used to show the limitations of a classical finite element formulation in 3D fabric simulations. Tension locking is highlighted in bias extension tests and a reduced integration hexahedral finite element with specific physical hourglass stabilization is proposed. Instabilities due to the highly anisotropic behavior law, witnessed in bending dominated situations, are exposed and a stabilization procedure is initiated.

Generalised Beam Theory for composite beams with longitudinal and transverse partial interaction

2016 ◽  
Vol 22 (10) ◽  
pp. 2011-2039 ◽  
Author(s):  
Gerard Taig ◽  
Gianluca Ranzi
Keyword(s):  
Structural Response ◽  
Beam Theory ◽  
Element Model ◽  
Composite Beams ◽  
Cross Sectional ◽  
Shear Connections ◽  
Dynamic Analyses ◽  
Partial Interaction ◽  
Deformation Modes ◽  
Generalised Beam Theory

This paper presents a Generalised Beam Theory formulation to study the partial interaction behaviour of two-layered prismatic steel–concrete composite beams. The novelty of the proposed approach is in its capacity to handle the deformability of the shear connections at the interface between the slab and steel beam in both the longitudinal and transverse directions in the evaluation of the deformation modes. This method falls within a category of cross-sectional analyses available in the literature for which a suitable set of deformation modes, including conventional, extension and shear, is determined from dynamic analyses of discrete planar frame models representing the cross-section. In this context, the shear connections are modelled using shear deformable spring elements. As a result, the in-plane partial shear interaction behaviour is accounted for in the planar dynamic analysis during the evaluation of the conventional and extension modes, while the longitudinal partial interaction behaviour associated with the shear modes is included in the out-of-plane dynamic analyses. In the case of the conventional modes, the longitudinal slip is accounted for in the post-processing stage where the warping displacements are determined. A numerical example of a composite box girder beam is presented and its structural response investigated for different levels of shear connection stiffness in both the longitudinal and transverse directions. The accuracy of the numerical results is validated against those obtained with a shell finite element model implemented in ABAQUS/Standard software.

Novel Hanger Design to Improve the Robustness of Through Arch Bridges

2011 ◽  
Vol 90-93 ◽  
pp. 862-868
Author(s):  
Qi Ming Wu ◽  
Dang Qi Yang ◽  
Fei Cui ◽  
Xiao Wei Yi ◽  
Rui Juan Jiang
Keyword(s):  
Progressive Collapse ◽  
Time History ◽  
Structural Members ◽  
New Approach ◽  
Arch Bridge ◽  
Structural Robustness ◽  
Arch Bridges ◽  
Dynamic Time ◽  
The Impact ◽  
Emergency Measures

Hangers in through arch bridges are important components since they suspend the bridge deck from the arch ribs. Local damage at a hanger may lead to progressive damage of various components in the arch bridge or even progressive collapse of the bridge. In this paper, the conventional design of double-hangers in through arch bridges is reviewed. Then a new approach to design the double-hangers is put forward. The suitability and robustness of this approach is then verified by a numerical simulation of a real through arch bridge. The impact effects induced by local hanger fracture on other structural members are simulated by dynamic time-history analyses. The new approach to design the hangers for through arch bridges is shown to improve the structural robustness. With the application of the new way put forward here, when one or more hangers are damaged to fail, the through arch bridge will not be endangered and will still maintain the overall load-bearing capacity during an appropriate length of time to allow necessary emergency measures to be taken, which illustrates the leading principle of structural robustness well.

A Qualitative Analysis of Oncology Patient Awareness of Medication Shortages and Their Preferences for How Shortages Should Be Managed

2020 ◽  
pp. JOP.19.00608
Author(s):  
Andrew Hantel ◽  
Fay J. Hlubocky ◽  
Mark Siegler ◽  
Christopher K. Daugherty
Keyword(s):  
Cancer Care ◽  
Management Practices ◽  
Care Center ◽  
Tertiary Care ◽  
Weighted Average ◽  
Structured Interview ◽  
Decision Makers ◽  
Oncology Patient ◽  
Cross Sectional ◽  
Multiple Decision Makers

PURPOSE: Medication shortages in US hospitals are ongoing, widespread, and frequently involve antineoplastic and supportive medications used in cancer care. The ways shortages are managed and the ways provider-patient communication takes place are heterogeneous, but the related preferences of oncology patients are undefined. This study sought to qualitatively evaluate patient preferences. METHODS: A cross-sectional, semi-structured interview study was conducted from January to June 2019. Participants were adult oncology inpatients who received primary cancer care at the University of Chicago, had undergone treatment within 2 years, and had 1 or more previous hospitalizations during that period. Participants (n = 54) were selected consecutively from alternating hematology and oncology services. The primary outcome was thematic saturation across the domains of awareness of medication shortages, principle preferences regarding decision makers, preferences regarding allocation of therapy drugs, and allocation-related communication. RESULTS: Thematic saturation was reached after 39 participants completed the study procedures (mean age, 59.6 years [standard deviation, 14.5 years]; men made up 61.5% of the study population [mean age, 24 years]; response rate, 72.0%). In all, 18% of participants were aware of institutional medication shortages. Patients preferred having multiple decision makers for allocating medications in the event of a shortage. A majority of patients named oncologists (100%), ethicists (92%), non-oncology physicians (77%), and pharmacists (64%) as their preferred decision makers. Participants favored allocation of drugs based on their efficacy (normalized weighted average, 1.3), and they also favored prioritizing people who were already receiving treatment (1.8), younger patients (2.0), sicker patients (3.1), and those presenting first for treatment (5.3). Most participants preferred preferred disclosure of supportive care medication shortages (74%) and antineoplastic medication shortages (79%) for equivalent substitutions. CONCLUSION: In a tertiary-care center with medication shortages, few oncologic inpatients were aware of shortages. Participants preferred having multiple decision makers involved in principle-driven allocation of scarce medications. Disclosure was preferred when their usual medications needed to be substituted with equivalent alternatives. These preliminary data suggest that preferences do not align with current management practices for medication shortages.

Optimization Design of Earthquake-Resistant Structure Taking Discrete Variables into Account

2010 ◽  
Vol 163-167 ◽  
pp. 2420-2423
Author(s):  
Hui Ji ◽  
Hong Sheng Zhao
Keyword(s):  
Strain Energy ◽  
Optimization Design ◽  
Design Method ◽  
National Standards ◽  
Engineering Practice ◽  
Discrete Variables ◽  
Cross Sectional ◽  
Earthquake Resistant ◽  
The Cost ◽  
Cost Of Construction

Conventionally, when optimizing a structure, the single target structural optimization design method is usually used. However, this design result often can not meet with the multiple requirements of construction; furthermore its optimizing efficiency is low; so its application is limited. And more, as the objective function being generally continuous variable, the optimized result is not the structural module and this is inconvenient for construction. This paper, taking the structural strain energy and the cost of construction as the targets to be optimized, and the design variable being discrete, provides multiple-target earthquake-resistant optimization design method aiming at obtaining the largest stain energy and the lowest construction cost, and established the function relation formula between the strain energy and the cost of construction and obtained the satisfied result. The highlight of this process is adopting discrete variables as the design variables, therefore the optimized results (cross-sectional dimensions) will conform to the requirements of structural module and the engineering practice. The optimization process presented in this paper conforms entirely to the national standards: “Code for Design of Reinforced Concrete Structures” (GB50010-2002) and “Code for Earthquake-resistant Design of Buildings” (GB50011). The theory and methods presented in this paper will be helpful for the structural design engineers and the researchers.

Tax harmonisation and tobacco product prices in the European Union, 2004–2015

2018 ◽  
Vol 28 (4) ◽  
pp. 434-439 ◽  
Author(s):  
Ángel López-Nicolás ◽  
Michal Stoklosa
Keyword(s):  
Public Health ◽  
European Union ◽  
Weighted Average ◽  
Health Impact ◽  
Tobacco Product ◽  
Average Price ◽  
The European Union ◽  
Cross Sectional ◽  
Member States ◽  
Tobacco Tax

ObjectivesThe European Commission has formally opened a process of revision of its tobacco tax directive. The purpose of this study is to analyse the evolution of cigarette and roll-your-own (RYO) tobacco prices in order to identify avenues for the improvement of public health goals.MethodsPooled cross-sectional data on prices and taxes on cigarettes and RYO tobacco in the Member States over 2004–2015 is used to track the distributions of the most popular price category and the weighted average price of these products and to relate them to the underlying tax structure.ResultsThe inflation-adjusted prices for the two products have increased over the period, but the dispersion of prices across Member States has remained constant. Throughout the period, there was a pervasive price gap between cigarettes and RYO tobacco within the Member States. Such features are explained by the underlying tax design.DiscussionThe current tax stance has been successful at increasing both cigarette and RYO tobacco prices. To further enhance the public health impact of the European Union tax directive, the revision should promote the convergence of prices across Member States and aim at closing the price gap between cigarettes and RYO tobacco. These objectives call for increasing the mandatory minimum levels of excise duty on the two products, preferably linking them to the evolution of a European weighted average price. The pace of increase should be faster for RYO tobacco in order to close the gap with respect to cigarette prices.

scholarly journals Sickness certification in Singapore’s public primary healthcare system: A cross-sectional analysis

2017 ◽  
Vol 27 (3) ◽  
pp. 167-174 ◽  
Author(s):  
David Chee Chin Ng ◽  
Yii Jen Lew ◽  
Eileen Yi Ling Koh ◽  
Van Hai Nguyen ◽  
Hwee Bee Wong ◽  
...  
Keyword(s):  
Primary Care ◽  
Sick Leave ◽  
Primary Care Physicians ◽  
Weighted Average ◽  
Computer Assisted ◽  
Ageing Population ◽  
Upper Respiratory Tract ◽  
Sickness Certification ◽  
Cross Sectional ◽  
Sickness Absenteeism

Objectives: Sickness absenteeism has been rising in Singapore with sickness certification commonly performed by primary care physicians. The Primary Care Survey 2014 reported increased primary care demand driven by a rapidly ageing population and the prevalence of chronic disease. This article aims to determine the magnitude of outpatient sickness certification in all the polyclinics in Singapore and identify the demographic characteristics and factors influencing the taking of sick leave by the local multi-ethnic Asian patients. Design: A one-week, cross-sectional survey using computer-assisted interviews with age-stratified, systematically sampled patients was conducted at all 18 polyclinics in 2014. Sick leave data was then extracted from each polyclinic’s administrative system. Data was analysed with logistic regression to determine statistically significant factors. Results: The sickness certification rate was 22.6% during the study period with a weighted average duration of 1.42 days. Sickness certification was most associated with the younger age group (17–20 years; adjusted odd ratio (AOR) = 9.51), an acute condition (AOR = 24.8) and those living in 1–2 room public housing (AOR = 4.72). Among employees, those working in manufacturing industries had the most association with sickness certification while the finance and insurance industry had the least. An acute upper respiratory tract infection was the most frequent diagnosis for those who obtained medical certificates (38.7%). Conclusion: A medical certificate was issued in almost one-quarter of consultations in Singapore polyclinics. Sickness certification was predominated by short-term absence for acute conditions. Characterisation of sickness absenteeism among employees serves as a benchmark for future studies. Mitigation measures were discussed while exclusion of private primary care clinics probably led to an underestimation of the magnitude of sickness certification.

scholarly journals Determinants of agro pastoralists’ participation in irrigation scheme: the case of fentalle agro pastoral district, oromia regional state, Ethiopia

2016 ◽  
Vol 5 (2) ◽  
pp. 44-50 ◽  
Author(s):  
Abdi Etafa Regassa
Keyword(s):  
Logistic Regression ◽  
Performance Indicator ◽  
Scale Up ◽  
Irrigation Performance ◽  
Cross Sectional ◽  
Policy Makers ◽  
Indicator Variable ◽  
Irrigation Project ◽  
Input Use ◽  
Cooperative Organization

This paper analyzed the factors determining participation in irrigation project on agro pastoral household and their perception towards the scheme. The study result depends on cross-sectional data collected from a sample of 144 households of which 72 irrigation users and 72 non-users using a combination of multistage, stratified and random sampling. The data were analyzed using descriptive statistics and logistic regression to assess factors that affect participation in irrigation. Result revealed that agro pastoralists do have medium to very strong perception towards different aspects of irrigation performance indicator variable. It is observed that among the variables in logistic regression age, sex, income, input use and participation in cooperative organization have affected participation significantly and positively, while, farm experience, distance to the district market, and total livestock unit, affected participation in irrigation significantly and negatively. The study has also substantiated that irrigation in the study area has significant role on income and recommend that it shall be great and rewarding if policy makers, designers, implementers, and any funding agencies with similar interest. Further, capitalize and scale up the project to achieve the development plan and objective.Int. J. Agril. Res. Innov. & Tech. 5 (2): 44-50, December, 2015

What Matters from the Past: Market Value, Book Value, or Earnings? Earnings Valuation and Sufficient Statistics for Prior Information

1992 ◽  
Vol 7 (4) ◽  
pp. 423-464 ◽  
Author(s):  
Ram T.S. Ramakrishnan ◽  
Jacob K. Thomas
Keyword(s):  
Stock Prices ◽  
Time Series Data ◽  
Explanatory Power ◽  
Weighted Average ◽  
Market Value ◽  
Series Data ◽  
Cross Sectional ◽  
Sufficient Statistics ◽  
Book Value ◽  
Value Model

A number of recent analytical and empirical papers seek to identify the variables that best explain stock prices. We derive the relation between prices and earnings for three one-parameter “excess earnings” evolution processes that describe three different ways in which current period shocks to earnings persist in future. In each case, we show that price is a weighted average of capitalized current earnings and a sufficient statistic for all past information. The sufficient statistics are three amounts from last year: book value, market value, and capitalized earnings. Using time-series data over the 1969-1988 period for a sample of 511 firms, we estimate firm-specific excess earnings regressions and price regressions for the three cases. Although the book value model provides the best fit for a majority of firms for the excess earnings regressions, the market value model is far superior for the price regressions. We argue that this latter result is due to prior period price (included in the market value model alone), reflecting other information that is not explicitly modeled here. Despite this bias in favor of the market value model for the price regressions, we find a positive cross-sectional association between the relative explanatory power of the three models in the excess earnings regressions and the corresponding relative explanatory power in the price regressions. That is, if a firm's excess earnings series is best described by a particular model, its price series is also likely to be best described by the valuation relation derived from the same model.

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