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Steel T-welded joint structures have been largely applied in aerospace and marine infrastructures. The weld length in T-weld joint structures is usually long, and it is difficult to access the weld conditions for damage detection purposes. This is due to the T-welded joint structure possessing a more complex cross-section than the conventional welded plate-like structures. Rather than formed by two plates and joined with a butt weld, the joint regions in the T-welded joint structure are connected to the sides of three plates to form a T-welded joint, and hence cannot be considered as plate-like structures. This makes guided wave modes difficult to be identified and exploited. This paper assesses the feasibility to detect weld defects on a steel T-welded joint structure using the feature guided wave (FGW) technique. FGW technique can provide a fast and long-range inspection for local topographical features, such as welded joints, offering great potential for effective screening of damages. Semi-Analytical Finite Element (SAFE) method is applied to acquire modal solutions in the waveguide. A new algorithm is developed to obtain FGW modes with both high energy concentration and low attenuation from the solutions of SAFE eigenvalue problem. One particular FGW mode with similar mode shape as the Rayleigh surface wave is identified, of which the propagation occurs only in the joint region with small attenuation. This FGW, labelled Rayleigh T-welded wave (RTW), is explored in comprehensive experimental and numerical studies to investigate the propagation and backward scattering characteristics regarding optimal excitation frequency and different sizes of weld defect. The numerical and experimental results are in good agreement. The outcome of the study confirms the capability and robustness of RTW in detecting small weld defects, which allows a long-distance and sensitive screening for the small weld defects at the joint region in the T-welded joint structure.

© 2015 Elsevier Ltd. An investigation of shear transfer behavior in initially uncracked reinforced concrete members is conducted using finite element modeling method in this study. Although earlier experimental studies have been carried out to identify the role of different design parameters on the ultimate shear strength, there are no design provisions that are available to predict the relationship of shear stress to slip as a function of the basic parameters. One of the aims of this paper is to improve insight into the characteristics between the shear stress and slip for a range of design parameters, such as concrete strength, percentage of dowel and variation of lateral normal pressure on RC members. The other aim of this paper is to derive a set of simplified equations for evaluating the ultimate shear stress and relationship of shear stress to slip in practical structural design. High-fidelity finite element models are developed using LS-DYNA program to simulate push-off tests, and the models are calibrated using experimental results. Parametric studies are then carried out to generate data with the consideration of different combinations of the structural design parameters, i.e., concrete strength, percentage of dowel steel and lateral normal pressures. It is found that the numerical models are accurate in predicting the interface shear strength and slip occurring along the shear plane of the push-off test specimens. The study also shows that there is a good agreement in predicting the shear stress to slip relationship between the results calculated by simplified equations and numerical models, and experimental results.

© 2015 Elsevier Ltd. An investigation of shear transfer behavior in initially uncracked reinforced concrete members is conducted using finite element modeling method in this study. Although earlier experimental studies have been carried out to identify the role of different design parameters on the ultimate shear strength, there are no design provisions that are available to predict the relationship of shear stress to slip as a function of the basic parameters. One of the aims of this paper is to improve insight into the characteristics between the shear stress and slip for a range of design parameters, such as concrete strength, percentage of dowel and variation of lateral normal pressure on RC members. The other aim of this paper is to derive a set of simplified equations for evaluating the ultimate shear stress and relationship of shear stress to slip in practical structural design. High-fidelity finite element models are developed using LS-DYNA program to simulate push-off tests, and the models are calibrated using experimental results. Parametric studies are then carried out to generate data with the consideration of different combinations of the structural design parameters, i.e., concrete strength, percentage of dowel steel and lateral normal pressures. It is found that the numerical models are accurate in predicting the interface shear strength and slip occurring along the shear plane of the push-off test specimens. The study also shows that there is a good agreement in predicting the shear stress to slip relationship between the results calculated by simplified equations and numerical models, and experimental results.

Superparamagnetic nanoparticles with superhigh T2 relaxivity and cellular uptake are strongly desired for ultrasensitive magnetic resonance imaging (MRI). Towards this end, highly monodispersed manganese ferrite nanoparticles (MNPs, 6 nm) with mPEG-g-PEI and PEG coatings as model system are employed in this study to investigate the coating engineering for simultaneously high T2 relaxivity and cellular uptake. The quantitative evaluations of the intracellular uptake indicate that mPEG-g-PEI modified MNPs possess highly efficient cellular uptake, 2.4-fold larger than that with mPEG coating. More significantly, this coating simultaneously leads to a remarkably high T2 relaxivity up to 331.8 mm-1 s-1, which is 4 times larger than that of the mPEG control and the largest value reported for superparamagnetic iron oxides with similar size. Modeling analysis reveals that the superior relaxivity is mainly attributed to the largely reduced diffusivity of water molecules trapped in the mPEG-g-PEI net. Further MRI of MDA-MB-231 breast cancer cells loaded MNPs with mPEG-g-PEI coating demonstrated the strong MR contrast in vitro effect with a T2 relaxivity as high as 92.6 mm-1 s-1, 2.5-folds larger than reported 10 nm MNPs. This study provides a universal strategy of coating engineering of various magnetic nanoparticles for highly sensitive MRI.

The present theory leads to a set of subjective weights such that the utility of an uncertain alternative (gamble) is partitioned into three terms involving those weightsa conventional subjectively weighted utility function over pure consequences, a subjectively weighted value function over events, and a subjectively weighted function of the subjective weights. Under several assumptions, this becomes one of several standard utility representations, plus a weighted value function over events, plus an entropy term of the weights. In the finitely additive case, the latter is the Shannon entropy; in all other cases it is entropy of degree not 1. The primary mathematical tool is the theory of inset entropy.

The first author has known Peter for a very long time, dating back some 45 years to when we met at a colloquium he gave at the University of Pennsylvania. After that our paths crossed fairly often. For example, in the early 1970s, he spent a year at the Institute for Advanced Study where Luce spent three years until the attempt to establish a program in scientific social science was abandoned for a more literary approach favored by the humanists and, surprisingly, the mathematicians then at the Institute. The second author has learnt a tremendous amount about both substantive and technical issues from Peter's work, beginning with Peter's book Utility Theory for Decision Making (Fishburn, 1970), which he reviewed for Contemporary Psychology (see Marley, 1972). Peter's volume on interval orders (Fishburn, 1985) was a marvelous development of various ideas related to the algebra of imperfect discrimination that elaborated the first author's initial work on semiorders (Luce, 1956).

The present theory leads to a set of subjective weights such that the utility of an uncertain alternative (gamble) is partitioned into three terms involving those weightsa conventional subjectively weighted utility function over pure consequences, a subjectively weighted value function over events, and a subjectively weighted function of the subjective weights. Under several assumptions, this becomes one of several standard utility representations, plus a weighted value function over events, plus an entropy term of the weights. In the finitely additive case, the latter is the Shannon entropy; in all other cases it is entropy of degree not 1. The primary mathematical tool is the theory of inset entropy.

The first author has known Peter for a very long time, dating back some 45 years to when we met at a colloquium he gave at the University of Pennsylvania. After that our paths crossed fairly often. For example, in the early 1970s, he spent a year at the Institute for Advanced Study where Luce spent three years until the attempt to establish a program in scientific social science was abandoned for a more literary approach favored by the humanists and, surprisingly, the mathematicians then at the Institute. The second author has learnt a tremendous amount about both substantive and technical issues from Peter's work, beginning with Peter's book Utility Theory for Decision Making (Fishburn, 1970), which he reviewed for Contemporary Psychology (see Marley, 1972). Peter's volume on interval orders (Fishburn, 1985) was a marvelous development of various ideas related to the algebra of imperfect discrimination that elaborated the first author's initial work on semiorders (Luce, 1956).

We specialize our results on entropy-modified representations of event-based gambles to representations of probability-based gambles by assuming an implicit event structure underlying the probabilities, and adding assumptions linking the qualitative properties of the former and the latter. Under segregation and under duplex decomposition, we obtain numerical representations consisting of a linear weighted utility term plus a term corresponding to information-theoretical entropies. These representations accommodate the Allais paradox and most of the data due to Birnbaum and associates. A representation of mixed event-and probability-based gambles accommodates the Ellsberg paradox. We suggest possible extensions to handle the data not accommodated.

J. R. Meginniss modified expected utility to accommodate a concept of the utility of gambling that led to a representation composed of a utility expectation term plus an entropy of degree ? term. He imposed several apparently strong assumptions. One of these is that a number of unknown generating functions are identical. A second is that he assumed he was working with given probabilities. Here we follow his general framework but weaken considerably those assumptions. Our problem is reduced to solving some functional equations induced by gamble decomposition. From the solutions, we obtain the representation of the utility function. Further axiomatic restrictions are imposed that lead ultimately to Meginniss earlier result.

Behavioral axioms about preference orderings among gambles and their joint receipt lead to numerical representations consisting of a subjective utility term plus a term depending upon the events and the subjective weights. The results here are for uncertain alternatives, in much the same sense as Savages usage. Several open problems are described. Results for the risky case are in a second article.

J. R. Meginniss modified expected utility to accommodate a concept of the utility of gambling that led to a representation composed of a utility expectation term plus an entropy of degree ? term. He imposed several apparently strong assumptions. One of these is that a number of unknown generating functions are identical. A second is that he assumed he was working with given probabilities. Here we follow his general framework but weaken considerably those assumptions. Our problem is reduced to solving some functional equations induced by gamble decomposition. From the solutions, we obtain the representation of the utility function. Further axiomatic restrictions are imposed that lead ultimately to Meginniss earlier result.

Behavioral axioms about preference orderings among gambles and their joint receipt lead to numerical representations consisting of a subjective utility term plus a term depending upon the events and the subjective weights. The results here are for uncertain alternatives, in much the same sense as Savages usage. Several open problems are described. Results for the risky case are in a second article.

We specialize our results on entropy-modified representations of event-based gambles to representations of probability-based gambles by assuming an implicit event structure underlying the probabilities, and adding assumptions linking the qualitative properties of the former and the latter. Under segregation and under duplex decomposition, we obtain numerical representations consisting of a linear weighted utility term plus a term corresponding to information-theoretical entropies. These representations accommodate the Allais paradox and most of the data due to Birnbaum and associates. A representation of mixed event-and probability-based gambles accommodates the Ellsberg paradox. We suggest possible extensions to handle the data not accommodated.