Experimental Investigation into Steel Storage Rack Beam-to-Upright Bolted Connections

For unbraced steel storage racks, the down-aisle stability depends largely on the performance of beam-to-upright connections and column bases. Boltless connections are generally used in order to make rack structures easy to assemble and feasible to adjust the storey height. Recently, storage racks are designed to carry large amounts of goods and they are therefore raise a considerable height, which makes the improvement of the structural stability to be sufficiently important. Under the circumstances, tab-connected beam-to-upright connections with bolts are gradually used in steel storage racks. Compared with boltless connections, the stiffness, strength and ductility of the bolted connections are improved to some extent. This paper presents an experimental investigation into the moment-rotation characteristic of steel storage rack beam-to-upright bolted connections under monotonic loads. Seven groups of specimens were tested with different constructional details and three identical specimens were repeated for each group. Moreover, the single cantilever test method was employed to study the rotational behaviour of connections. Effects of various parameters, such as upright thickness, beam height and tab numbers on connection behaviour are discussed and presented in this paper. The experiments show that the failure modes of bolted beam-to-upright connections depend on the relative thickness between the upright and beam-end-connector, as well as the relative height between the beam and beam-end-connector. Furthermore, the results obtained from the present study highlight that the behaviour of connections, such as stiffness and ultimate moment capacity, are considerably influenced by the specific constructional details

Cardiac Imaging in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a relatively common inherited cardiomyopathy, which is occasionally challenging to differentiate from hypertensive heart disease and athlete hearts on the basis of morphologic or functional abnormalities alone. Imaging studies provide solutions for most clinical needs, from diagnosis, anatomical and functional assessment, family screening, risk stratification, to monitoring of treatment response. Generally, transthoracic echocardiography is used as first-line imaging tool to establish the diagnosis. A multimodality imaging approach (cardiac magnetic resonance, cardiac computed tomography, and cardiac nuclear imaging) is also encouraged in the assessment of these patients. The choice of imaging tool should be based on a broad perspective and expert knowledge of what each technique has to offer, including its specific advantages and disadvantages. In this chapter, we discuss the utility and pitfalls of established imaging modalities and discuss the evolving role of novel echocardiographic imaging modalities

Interpret Vision Transformers as ConvNets with Dynamic Convolutions

There has been a debate about the superiority between vision Transformers and ConvNets, serving as the backbone of computer vision models. Although they are usually considered as two completely different architectures, in this paper, we interpret vision Transformers as ConvNets with dynamic convolutions, which enables us to characterize existing Transformers and dynamic ConvNets in a unified framework and compare their design choices side by side. In addition, our interpretation can also guide the network design as researchers now can consider vision Transformers from the design space of ConvNets and vice versa. We demonstrate such potential through two specific studies. First, we inspect the role of softmax in vision Transformers as the activation function and find it can be replaced by commonly used ConvNets modules, such as ReLU and Layer Normalization, which results in a faster convergence rate and better performance. Second, following the design of depth-wise convolution, we create a corresponding depth-wise vision Transformer that is more efficient with comparable performance. The potential of the proposed unified interpretation is not limited to the given examples and we hope it can inspire the community and give rise to more advanced network architectures

On Black Ring with a Positive Cosmological Constant

We consider black ring with a cosmological constant in the five dimensional N=4 de Sitter supergravity theory. Our solution preserves half of the de Sitter supersymmetries and has one rotation symmetry. Unlike the flat case, there is no angular momentum and the stability against gravitational self-attraction is balanced by the cosmological repulsion due to the cosmological constant. Our solution describes a singular black ring since although it has horizons of topology S^1 x S^2, the horizons are singular. Despite the singularity, our solution displays some interesting regular physical properties: it carries a dipole charge and this charge contributes to the first law of thermodynamics; it has an entropy and mass which conform to the entropic N-bound proposal and the maximal mass conjecture We conjecture that the Gregory-Laflamme instability leads to a resolution of the singularity and results in a regular black ring.Comment: v2. LaTex, 19 pages. with some corrections and comments adde

USA educator perspectives regarding the nature and value of social and emotional learning

This paper discusses the US educator perspectives regarding the nature and value of Social Emotional Learning (SEL) skills. This research is part of a larger study being conducted by 33 career development investigators from 15 countries. SEL skills are becoming increasingly critical to helping youth develop the competencies needed to become employable within the emergent 4th Industrial Revolution. Today’s youth must articulate how their competencies align to multiple career opportunities. They need relationship skills and social awareness to interact with different managers and work environments. Youth need self-management skills to advance in the workplace and engage in lifelong learning. For this study, educators were asked to provide written responses to a series of open-ended questions about their understanding of SEL, their perspective on SEL’s relevance to their own effectiveness as educators, and whether and how they perceive SEL as relevant to teaching in classroom settings. This paper will report on the results of how U.S. educators perceive the value and relevance of SEL. Using a modified grounded theory approach, responses from 40 educators were analyzed and 123 SEL themes emerged. The results will be discussed in relation to existing SEL and career readiness frameworks.First author draf

One-loop Helicity Amplitudes for Top Quark Pair Production in Randall-Sundrum Model

In this paper, we show how to calculate analytically the one-loop helicity amplitudes for the process $q\bar{q} rightarrow t\bar{t}$ induced by KK gluon, using the spinor-helicity formalism. A minimal set of Feynman rules which are uniquely fixed by gauge invariance and the color representation of the KK gluon are derived and used in the calculation. Our results can be applied to a variety of models containing a massive color octet vector boson.Comment: 37 pages, 10 figures, journal versio