pinecone/core-2020-05-10-deduplication huggingface dataset:
Earthquake-induced shear concentration in shear walls above transfer structures

Due to various architectural constraints and multi-functional requirements for modern buildings, combined structural forms, which typically include shear wall systems in higher zones and moment-resisting frames together with core walls in lower zones, are commonly used for these buildings. Transfer structures are often introduced to transfer the loads from higher to lower zones. Previous experimental and numerical studies have demonstrated that the exterior walls above the transfer structure are particularly vulnerable structural members under seismic loading. In this paper, a qualitative model is presented for simulating the shear concentration effect in exterior walls with consideration of the local deformations of transfer structures. A parametric study was carried out to validate the model and to quantify various factors which may influence the shear concentration effect. A shear concentration factor, which can measure the intensity of shear stress concentration in the exterior walls, is defined. Based on the numerical study, design principles are recommended to seismic engineers for minimizing the adverse shear concentration effect on exterior walls under seismic loads. Copyright © 2008 John Wiley & Sons, Ltd.postprin
Earthquake input energy to tall and base-isolated buildings in time and frequency dual domains

Earthquake input energies to tall and base-isolated buildings are examined by both time-domain and frequency-domain methods. Both methods support the validity of evaluating the earthquake input energy each other. It is shown that both methods have different advantages and can compensate for each other. While the time-domain method has a long history and is applicable to nonlinear models as well, the frequency-domain method is characterized by the energy transfer function and its equi-area property plays an important role in the discussion of the stability of earthquake input energy. This equi-area property can be derived by the residue theorem only in a simple model. It is also demonstrated that this equi-area property in multi-degree-of-freedom models can be derived by the time-domain method for an idealized model of input motions with a constant Fourier amplitude spectrum. This idea is applied to tall and base-isolated buildings. The equi-area property of the energy transfer function provides a stable characteristic on the input energy as far as the total mass of the buildings is constant
Instantaneous earthquake input energy and sensitivity in base-isolated building

The input energy and energy input rate to a base-isolated (BI) building during an earthquake are considered and formulated in the frequency domain. The frequency-domain approach for computation of input energy and energy input rate has different remarkable advantages compared with the conventional time-domain approach. It is demonstrated that the input energy can be of a compact form via the frequency integration of the product between the input component (squared Fourier amplitude spectrum of acceleration) and the structural model component (so-called energy transfer function). Furthermore, the energy input rate can also be of a similar form via the frequency integration of the product between the instantaneous power spectrum and the energy transfer function. With the help of this compact form, it is shown that the formulation in the frequency domain is essential for deriving arbitrary-order closed-form sensitivities of the input energy and energy input rate with respect to uncertain stiffness and damping coefficients in the BI storey. The closed-form sensitivity expressions provide us with information on the most unfavourable variation of the uncertain parameters that leads to the maximum input energy and input rate. Copyright © 2009 John Wiley & Sons, Ltd
Parametric and comparative study of spandrel beam effect on the punching shear strength of reinforced concrete flat plates

The safe and efficient construction of reinforced concrete flat plate systems requires an accurate, reliable and universally applicable procedure for the punching shear strength design.  A nonlinear layered finite element method (LFEM) capable of analysing the punching shear strength of such system has been developed.  Based on the LFEM, a parametric study is undertaken to evaluate some of the factors influencing punching shear strength of reinforced concrete flat palate with spandrel beams. This is done by varying the depth and the width of the spandrel beam while keeping other variables constant.  The numerical results obtained by the LFEM are also compared with those predicted by the recommendations of the Australian Standard (AS3600-2009) and the Wollongong-Griffith semi-empirical method.  The results confirm that the Australian Standard is inadequate in predicting the punching shear strength at the corner and edge column connections of flat plates with spandrel beams or torsion strips.Griffith Sciences, Griffith School of EngineeringFull Tex
Numerical and comparative study of earthquake intensity indices in seismic analysis

Elastoplastic and time-dependent analysis of seismic structures has become a major analysis technique in popularly accepted performance-based seismic design. However, the primary diffi culty in using this technique is the lack of a unifi ed criterion in the selection of various intensity indices of ground motions. Various earthquake factors infl uencing the elastoplastic response of seismic structures are highly sophisticated. Hence, it is vitally important to choose an appropriate and comprehensive earthquake intensity index to achieve an accurate correlation with the structural performance. In this study, a total of 30 earthquake intensity indices published in the literature are reviewed and are evaluated through correlation analysis based on 60 ground motion records. Examined herein is the correlation between existing earthquake intensity indices and the seismic responses of elastoplastic single degree-of-freedom and multi degree-of-freedom systems. The characteristics and applicability of such indices are also discussed in some detail, based on which appropriate earthquake intensity indices are recommended.Full Tex
Experimental behaviour of high-strength concrete deep beams with web openings

This paper focuses on an experimental study undertaken on High Strength Concrete (HSC) deep beams with various opening sizes and locations on the web. The test covers a wide scope of variables that have not been investigated in previous research. Apart from highlighting the experimental setup, failure loads and typical crack patterns of the test specimens are also reported. Experimental results are then compared with predictions using currently available design methods. The comparison indicates that the predictions using current design methods can overly underestimate or sometimes overestimate the ultimate strength of these HSC deep beams. Further, the reduction of ultimate strengths due to the existence of web openings is not considered adequately in these design methods. To rectify the shortcomings of current design formulae, a new design equation is proposed and compared with the experimental results and those from previous studies on the related topics. The accuracy and reliability of the proposed new equation is subsequently confirmed. Based on the outcome of this work, more experimental tests with various opening configurations including shape and location of web openings are recommended for future study.Griffith Sciences, Griffith School of EngineeringFull Tex
Deformability design of high-performance concrete beams

The use of high-performance materials (HPMs) such as high-strength concrete (HSC) and high-strength steel (HSS) is becoming more popular in the construction of beams and columns of tall buildings. These HPMs not only increase the stiffness and decrease the strength-to-weight ratio, but also provide a more sustainable construction method by minimising the construction materials needed. However, HSC and HSS are more brittle than normal-strength concrete and steel, respectively. Therefore, it will adversely affect the deformability of concrete beams. To evaluate the pros and cons of adopting HPM in beam design, the author will investigate the flexural strength and deformability of concrete beams made of HPMs. The deformability in this study is expressed in normalised rotation capacity and investigated by a parametric study using nonlinear moment-curvature analysis taking into account the degree of reinforcement, confining pressure, concrete and steel yield strength. From the results, it is evident that the deformability of concrete beams increases as the degree of reinforcement decreases or confining pressure increases. However, the effects of concrete and steel yield strength depend on other factors. For practical design purpose, charts and formulas are produced for designing high-performance concrete beams to meet with specified flexural strength and deformability requirement. © 2011 John Wiley & Sons, Ltd.preprin
Allenyl-β-lactams: Versatile scaffolds for the synthesis of heterocycles

The hybrid allenic β-lactam moiety represents an excellent building block for carbo- and heterocyclization reactions, affording a large number of cyclic structures containing different sized skeletons in a single step. This strategy has been studied under thermal and radical-induced conditions. More recently, the use of transition-metal catalysis has been introduced as an alternative that relies on the activation of the allenic component. On the other hand, the intramolecular version has attracted much attention as a strategy for the synthesis of bi- and tricyclic compounds in a regio- and stereoselective manner. This overview focuses on the most recently developed cyclizations on 2-azetidinone-tethered allenes along with remarkable early works accounting for the mechanism, as well as for the regio- and diastereoselectivities of the cyclizations. © 2011 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.Peer Reviewe
Module assembly for designing multivalent mid-sized inhibitors of protein-protein interactions.

Developing clinically relevant synthetic agents that are capable of disrupting protein-protein interactions (PPIs) is now a major goal of scientific research. In an effort to explore new methodologies that are applicable to the design of synthetic PPI inhibitors, we examined a strategy based on the assembly of small module compounds to create multivalent mid-sized agents. This personal account describes three particular approaches based on module assembly: metal-chelating-based ligand assembly, covalent chemical ligation templated by a targeted protein, and bivalent inhibitor design for simultaneous targeting of the active pocket and protein surface. These strategies were shown to be useful for synthesizing minimally sized synthetic agents for targeting PPIs and may enable development of agents that are applicable to inhibition of intracellular PPIs
Synthesis and biological activities of simplified analogs of the natural PKC ligands, bryostatin-1 and aplysiatoxin.

Protein kinase C (PKC) isozymes play central roles in signal transduction on the cell surface and could serve as promising therapeutic targets of intractable diseases like cancer, Alzheimer's disease, and acquired immunodeficiency syndrome (AIDS). Although natural PKC ligands like phorbol esters, ingenol esters, and teleocidins have the potential to become therapeutic leads, most of them are potent tumor promoters in mouse skin. By contrast, bryostatin-1 (bryo-1) isolated from marine bryozoan is a potent PKC activator with little tumor-promoting activity. Numerous investigations have suggested bryo-1 to be a promising therapeutic candidate for the above intractable diseases. However, there is a supply problem of bryo-1 both from natural sources and by organic synthesis. Recent approaches on the synthesis of bryo-1 have focused on its simplification, without decreasing the ability to activate PKC isozymes, to develop new medicinal leads. Another approach is to use the skeleton of natural PKC ligands to develop bryo-1 surrogates. We have recently identified 10-methyl-aplog-1 (26), a simplified analog of tumor-promoting aplysiatoxin (ATX), as a possible therapeutic lead for cancer. This review summarizes recent investigations on the simplification of natural PKC ligands, bryo-1 and ATX, to develop potential medicinal leads
Applications of time-domain spectroscopy to electron-phonon coupling dynamics at surfaces.

Article first published online: 19 AUG 2014Photochemistry is one of the most important branches in chemistry to promote and control chemical reactions. In particular, there has been growing interest in photoinduced processes at solid surfaces and interfaces with liquids such as water for developing efficient solar energy conversion. For example, photoinduced charge transfer between adsorbates and semiconductor substrates at the surfaces of metal oxides induced by photogenerated holes and electrons is a core process in photovoltaics and photocatalysis. In these photoinduced processes, electron-phonon coupling plays a central role. This paper describes how time-domain spectroscopy is applied to elucidate electron-phonon coupling dynamics at metal and semiconductor surfaces. Because nuclear dynamics induced by electronic excitation through electron-phonon coupling take place in the femtosecond time domain, the pump-and-probe method with ultrashort pulses used in time-domain spectroscopy is a natural choice for elucidating the electron-phonon coupling at metal and semiconductor surfaces. Starting with a phenomenological theory of coherent phonons generated by impulsive electronic excitation, this paper describes a couple of illustrative examples of the applications of linear and nonlinear time-domain spectroscopy to a simple adsorption system, alkali metal on Cu(111), and more complex photocatalyst systems
Atomic defects in titanium dioxide.

The functionality of solid materials is defined by the type and ordering of the constituent atoms. By introducing defects that perturb the ordered structure, new functionality is created within the solid material. Atomic defects in titanium dioxide, such as oxygen vacancies, atomic hydrogen, and interstitial Ti, typically create new functionality. However, the fundamental physical properties of atomic defects in TiO2 are not fully understood and still remain controversial. In this account, the progress and issues for debate regarding the physical properties, electronic structure, and manipulation mechanisms of atomic defects in TiO2 as well as their interaction with gold nanoclusters are described
Catalytic Asymmetric Transfer Hydrogenation of Imines: Recent Advances

In this review article recent developments in the asymmetric transfer hydrogenation of imines from 2008 up to today are presented. The main methodology involves either metal-catalyzed procedures in the presence of a chiral ligand or organocatalyzed technologies using a Hantzsch ester and a chiral BINOL-derived phosphoric acid. The most important procedures are collected, paying special attention to the application of this methodology in synthetic organic chemistry.We thank the continued financial support from our Ministerio de Ciencia e Innovación (MICINN; projects CTQ2007-62771/BQU, CTQ2010-20387, CONSOLIDER INGENIO 2010-CDS2007-00006, CTQ2011-24151, CTQ2011-24165), the Ministerio de Economía y Competitividad (MINECO; projects CTQ2013-43446-P, CTQ2014-51912-REDC, CTQ2014-53695-P), FEDER, the Generalitat Valenciana (PROMETEO 2009/039, PROMETEOII/2014/017), and the University of Alicante
Applications of “Hot” and “Cold” Bis(thiosemicarbazonato) Metal Complexes in Multimodal Imaging

The applications of coordination chemistry to molecular imaging has become a matter of intense research over the past 10 years. In particular, the applications of bis(thiosemicarbazonato) metal complexes in molecular imaging have mainly been focused on compounds with aliphatic backbones due to the in vivo imaging success of hypoxic tumors with PET (positron emission tomography) using 64CuATSM [copper (diacetyl-bis(N4-methylthiosemicarbazone))]. This compound entered clinical trials in the US and the UK during the first decade of the 21st century for imaging hypoxia in head and neck tumors. The replacement of the ligand backbone to aromatic groups, coupled with the exocyclic N's functionalization during the synthesis of bis(thiosemicarbazones) opens the possibility to use the corresponding metal complexes as multimodal imaging agents of use, both in vitro for optical detection, and in vivo when radiolabeled with several different metallic species. The greater kinetic stability of acenaphthenequinone bis(thiosemicarbazonato) metal complexes, with respect to that of the corresponding aliphatic ATSM complexes, allows the stabilization of a number of imaging probes, with special interest in “cold” and “hot” Cu(II) and Ga(III) derivatives for PET applications and 111In(III) derivatives for SPECT (single-photon emission computed tomography) applications, whilst Zn(II) derivatives display optical imaging properties in cells, with enhanced fluorescence emission and lifetime with respect to the free ligands. Preliminary studies have shown that gallium-based acenaphthenequinone bis(thiosemicarbazonato) complexes are also hypoxia selective in vitro, thus increasing the interest in them as new generation imaging agents for in vitro and in vivo applications
Theoretical Study on Highly Active Bifunctional Metalloporphyrin Catalysts for the Coupling Reaction of Epoxides with Carbon Dioxide

Highly active bifunctional metalloporphyrin catalysts were developed for the coupling reaction of epoxides with CO2 to produce cyclic carbonates. The bifunctional catalysts have both quaternary ammonium halide groups and a metal center. To elucidate the roles of these catalytic groups, DFT calculations were performed. Control reactions using tetrabutylammonium halide as a catalyst were also investigated for comparison. In the present article, the results of our computational studies are overviewed. The computational results are consistent with the experimental data and are useful for elucidating the structure-activity relationship. The key features responsible for the high catalytic activity of the bifunctional catalysts are as follows: 1) the cooperative action of the halide anion (nucleophile) and the metal center (Lewis acid); 2) the near-attack conformation, leading to the efficient opening of the epoxide ring in the rate-determining step; and 3) the conformational change of the quaternary ammonium cation to stabilize various anionic species generated during catalysis, in addition to the robustness (thermostability) of the catalysts
Physicochemical Nature of Perfluoroalkyl Compounds Induced by Fluorine

Perfluoroalkyl (Rf) compounds have unique characters represented by a significantly high hydrophobic property, which often makes us consider that Rf groups should be interacted with each other via the ‘hydrophobic interaction’ as found for a normal hydrocarbon. Due to a similar intuitive and simplistic speculation, the Rf-specific material properties have long been enveloped in darkness for comprehensive understanding, which should lucidly be discussed within a framework of physical chemistry. Here, we show studies on the stratified dipole arrays (SDA) theory, which readily explains the Rf-specific material characters in a comprehensive manner based on only a few fundamental physical parameters of fluorine. The SDA theory encompasses some conventional theories that account for only a part of material properties. In addition, we show that the concept of vibrational spectroscopy of Rf compounds should also be revised, since the mass of fluorine is larger than that of carbon, which is opposite to the hydrocarbon case. In this manner, chemistry of Rf compounds needs another fully revised concept, which cannot be replaced by an extended concept of normal hydrocarbon compounds
Toward a new conception of conceptions: Interplay of talk, gestures, and structures in the setting

International audienceA major part of studies about students' conceptions and conceptual change exclusively is based on the analysis language, which is treated as a tool to make private contents of mind public to researchers. Following recent studies that focus (a) on language and discursive practice and (b) on the pragmatics of communication that draws on talk, gestures, and semiotic resources in the setting, we propose a redefinition of the nature of conception. Conceptions are understood as the simultaneously available speech, gestures, and contextual structures that cannot be reduced to verbal rendering because gestures and contextual structures constitute different modalities in the communication. Drawing on data collected during a physics unit about gas taught in French tenth-grade classrooms, we show why an appropriate account of conceptions requires (a) gestures simultaneously produced with talk and (b) identification of the relevant structures in the setting used by the participants as meaning-making (semiotic) resources. We propose to (a) reconceptualize the notion of conception by defining an "idea" as consisting of all relevant semiotic (meaning-making) resources publicly made available by a speaker (talk, gesture, context) and (b) consider conceptual change through the temporal evolution of ideas defined in this manner
Profiles of freshman physics' views on the nature of science

This is the accepted version of the following article: Ibrahim, B., Buffler, A. & Lubben, F. 2009. 'Profiles of freshman physics' views on the nature of science. Journal of Research in Science Teaching. 46(3): 248-264. DOI: 10.1002/tea.20219.., which has been published in final form at: http://dx.doi.org/10.1002/tea.20219.The views on various aspects of the nature of science (NOS) of 179 novice undergraduate physics students were investigated using six open-ended, written probes. These views were consolidated within compact NOS “profiles,” which were designed based on the students' responses to the probes. These profiles may be understood as sets of key descriptors, which represented the variation in the views of individual students in a succinct way. The views of 86% of the sample were found to be represented by four profiles, each containing five descriptors. The consequences for the teaching and learning of tertiary science, and advantages for linking NOS views to other research observables were explored
Real world contexts in PISA science : implications for context-based science education

The PISA assessment instruments for students’ scientific literacy in 2000, 2003 and 2006 have each consisted of units made up of a real world context involving Science and Technology, about which students are asked a number of cognitive and affective questions.  This paper discusses a number of issues from this use of S&T contexts in PISA and the implications they have for the current renewed interest in context-based science education.  Suitably chosen contexts can engage both boys and girls.  Secondary analyses of the students’ responses using the contextual sets of items as the unit of analysis provides new information about the levels of performance in PISA 2006 Science.  .Embedding affective items in the achievement test did not lead to gender/context interactions of significance, and context interactions were less than competency ones. A number of implications for context-based science teaching and learning are outlined and the PISA 2006 Science test is suggested as a model for its assessment