This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.

Introduction to the Finite Element Method

A critical review of the use of 3-D printing in the construction industry

지각된 유용성(Perceived Usefulness)의 영향분석

The review outlines modern trends in theoretical developments, novel designs and modern applications of sandwich structures. The most recent work published at the time of writing of this review is considered, older sources are listed only on as-needed basis. The review begins with the discussion on the analytical models and methods of analysis of sandwich structures as well as representative problems utilizing or comparing these models. Novel designs of sandwich structures is further elucidated concentrating on miscellaneous cores, introduction of nanotubes and smart materials in the elements of a sandwich structure as well as using functionally graded designs. Examples of problems experienced by developers and designers of sandwich structures, including typical damage, response under miscellaneous loads, environmental effects and fire are considered. Sample applications of sandwich structures included in the review concentrate on aerospace, civil and marine engineering, electronics and biomedical areas. Finally, the authors suggest a list of areas where they envision a pressing need in further research.

Review of current trends in research and applications of sandwich structures

Shared decision-making is increasingly advocated as an ideal model of treatment decision-making in the medical encounter. To date, the concept has been rather poorly and loosely defined. This paper attempts to provide greater conceptual clarity about shared treatment decision-making, identify some key characteristics of this model, and discuss measurement issues. The particular decision-making context that we focus on is potentially life threatening illnesses, where there are important decisions to be made at key points in the disease process, and several treatment options exist with different possible outcomes and substantial uncertainty. We suggest as key characteristics of shared decision-making (1) that at least two participants-physician and patient be involved; (2) that both parties share information; (3) that both parties take steps to build a consensus about the preferred treatment; and (4) that an agreement is reached on the treatment to implement. Some challenges to measuring shared decision-making are discussed as well as potential benefits of a shared decision-making model for both physicians and patients.

Shared Decision-making in the Medical Encounter: What Does It Mean? (Or, It Takes at Least Two to Tango)

Preconception care is an opportunity for detecting potential health risks in future parents and providing health behavior education to reduce morbidity and mortality for women and their offspring. Preconception care has been established in maternal and child health hospitals in Shanghai, China, which consists of health checkups, health education and counseling. This study investigated factors associated with the utilization of preconception care, and the role of preconception care on health behavior changes before conception among pregnant women and their partners. A cross-sectional study was conducted among pregnant women at three maternal and child health hospitals in Shanghai. The participants were invited to complete a self-administered questionnaire on the utilization of preconception care and health behavioral changes before conception. Of the 948 recruited pregnant women, less than half (42.2%) reported that they had utilized preconception care before the current pregnancy. Unplanned pregnancy, unawareness of preconception care and already having a general physical examination were the main reasons for not attending preconception care. The two main sources of information about preconception care were local community workers and health professionals. Younger women and the multipara were less likely to utilize preconception care. Women who utilized preconception care were more likely to take folic acid supplements before conception [Adjusted Odds Ration (aOR) 3.27, 95% Confidence Interval (CI) 2.45–4.36, P < 0.0001]. The partners of pregnant women who had attended preconception care services were more likely to stop smoking [aOR 2.76, 95%CI 1.48–5.17, P = 0.002] and to stop drinking [aOR 2.13, 95%CI 1.03–4.39, P = 0.041] before conception. Utilization of preconception care was demonstrated to be positively associated with preconception health behavior changes such as women taking folic acid supplements before pregnancy, their male partner stopping smoking and drinking before conception. Future studies are needed to explore barriers to utilizing preconception care services and understand the quality of the services. Strategies of promoting preconception care to expectant couples, especially to young and multipara women, should be developed to further improve the utilization of the services at the community level.

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Utilization of preconception care and its impacts on health behavior changes among expectant couples in Shanghai, China

Rehabilitation of Reinforced Concrete T-Beam Structures Using Externally Bonded FRP Composites

Insulated sandwich panels consist of two layers of wythe separated by a foam insulation. Many different types of connectors have been used in the past to connect the two wythes, including steel ties, wire trusses, bent wires, truss-shaped connectors, and solid concrete zones. In recent year, fiber-reinforced polymer (FRP) materials, in both truss and mesh configurations, have begun to be incorporated as shear connectors, as they have a thermal conductivity about 14% that of steel, and can significantly reduce thermal bridging. Until now, there is no effective guidelines for the design of these panels. Generally, they are treated as rectangular beams, which is not reasonable since the longitudinal stress over the wythe section is non-uniform due to the in-plane shear flexibility of the wythe, which is called shear lag effect. Effective flange width has been used to describe the shear lag effect for a deck-ongirder composite beam system, reducing a three dimensional behavior of the composite beam system to the analysis of a T-beam section with a reduced width of deck. This paper extends the concept of effective flange width to insulated concrete sandwich panels. A shear lag model is firstly developed to study the sandwich panel system, where partial Degree of Composite Action (DCA) due to flexible FRP shear connector is considered. The analytical model is then verified through close correlations between finite element and analytical results for a concrete sandwich panel with FRP shear connectors. Next, a parametric study is conducted using the analytical model to study the effects of deck stiffness and aspect ratio on effective flange width. Finally, a simplified method is proposed to calculate effective width.

Effective Width of Insulated Sandwich Panels with Flexible FRP Shear Connectors Considering Partial Degree of Composite Action

Partial replacement of Portland cement by industrial by-products such as fly ash and silica fume (collectively known as mineral admixtures) in the normal concrete diverts the deposition of those by-products from landfills, reduces CO2 emissions, and produces durable and sustainable concrete. Shrinkage strain is a major parameter for concrete durability. No systematic data are available to predict the shrinkage of concrete containing mineral admixtures from paste properties to coupon level. In this study, composite modeling was developed from paste level to coupon level for 10 concrete mixtures containing fly ash, and, silica fume, individually as well as in combination, at two different w/cm ratios. Then a two-step composite model was used; firstly to find the shrinkage of mortar from the paste and then the range of the concrete shrinkages was determined using the shrinkage of the mortar and the Hashin-Shtrikman bounds (1963) with the corresponding elastic modulus. The prediction model agreed well with experimental data. The predicted shrinkages from the ACI 209R and CEB M90-99 were computed and the predicted model was found to be in close agreement with the experimental results.

Prediction of Shrinkage of Concrete Containing Fly Ash and/or Silica Fume Using Composite Modeling

A sensing skin has been employed to detect and monitor cracks in reinforced concrete specimens. This sensing skin is constituted of a flexible electronic termed soft elastomeric (SEC) capacitor, which detects a change in strain through changes in capacitance. The SEC is a low cost and robust sensing technology that has previously been studied for the monitoring of fatigue cracks in steel bridges. The sensor is highly elastic and as such offers a unique capability to detect and monitor the growth of cracks in structural elements. In this study, an array of surfacedeployed SECs was used to detect and locate bending-induced cracks. To validate the proposed approach, an experimental campaign was conducted using reinforced concrete beams. Threepoint bending tests were conducted on two small-scale reinforced concrete beams. Different configurations of SEC arrays were used on the two specimens to assess the capacity and limitation of the proposed approach. Results show that the sensing skin was capable of detecting and localizing cracks that formed in both specimens. Additionally, the sensor is shown to offer a good signal-to-noise ratio and thus could represent a cost-effective alternative to current sensing technologies for the monitoring of cracks in concrete structures.

An Chen

Papers

Utilization of preconception care and its impacts on health behavior changes among expectant couples in Shanghai, China

Rehabilitation of Reinforced Concrete T-Beam Structures Using Externally Bonded FRP Composites

Effective Width of Insulated Sandwich Panels with Flexible FRP Shear Connectors Considering Partial Degree of Composite Action

Prediction of Shrinkage of Concrete Containing Fly Ash and/or Silica Fume Using Composite Modeling

Detection and Monitoring of Cracks in Reinforced Concrete Using an Elastic Sensing Skin