116,942 research outputs found
Cas9 deactivation with photocleavable guide RNAs
No full textRaw gel images for:
Zou RS*, Liu Y*, Wu B, Ha T. (2021). Cas9 deactivation with photocleavable guide RNAs. Molecular Cell
Skin-Stiffener Separation in T-Stiffened Composite Specimens in Postbuckling Condition
No full textAn experimental and numerical investigation was conducted to study the skin-stiffener separation of single T-shape stiffener specimens in postbuckling condition. Three specimens were manufactured with a centrally located Teflon insert, and were loaded in compression until collapse. Deformation patterns and separation evolution were monitored during the tests. To measure the full-field displacements and the strain distributions of the specimens, a digital image correlation (DIC) system was used. Skin-stiffener separation was observed and measured with an ultrasound system. Finite-element (FE) analyses were conducted to capture interlaminar damage mechanism based on the virtual crack closure technique. The numerical analysis accurately predicted the postbuckling deformation and the skin-stiffener separation behavior. The close correlation between the experimental and numerical results allows for further exploitation of the strength reserve in the postbuckling region and wider design options for the next generation of composite aircraft designs.</p
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Full-Range Behavior of Fiber Reinforced Cementitious Matrix (FRCM)-Concrete Joints using a Trilinear Bond-Slip Relationship
No full textInterfacial debonding of fiber reinforced cementitious matrix (FRCM)-concrete joints can be considered as a mainly mode-II fracture process, a problem that can be solved by accounting for one-dimensional interfacial shear stress-slip relationships. This paper presents an analytical approach to predict the load response of FRCM-concrete joints by adopting a trilinear bond-slip relationship consisting of a linear-elastic branch, a softening branch, and a friction branch. The applied load-global slip response of FRCM-concrete joints with (relatively) long bonded length includes five stages: elastic, elastic-softening, elastic-softening-debonding, softening-debonding, and debonding stages. Closed-form solutions of the interfacial slip, shear stress, and axial stress (or strain) distribution along the bonded length are provided. The response of FRCM-concrete joints with (relatively) short bonded length is examined. The effective bond length and a critical length for the existence of the snap-back phenomenon are derived. Experimental results reported in the literature are used to calibrate the parameters needed for the analytical approach. The analytical results are then compared with experimental results and with numerical results determined using a finite difference method (FDM). Finally, the capability of determining the parameters in the trilinear bond-slip relationship using a neural network (NN) with the experimental load response as the input is investigated
Fiscal Decentralization, the Composition of Public Spending, and Regional Growth in India
No full textIn this paper, we present an analytical model for examining the growth impact of intergovernmental and intersectoral allocation of public expenditure. The model helps us quantify the role of fiscal decentralization in regional economic growth and identify whether central and local allocation of public spending among various sectors are growth-enhancing. Applying our analytical framework to a panel data set of 16 major states in India, we have found that, in many cases of our regressions, fiscal decentralization is positively, and even statistically significantly, associated with state economic growth. The state allocation of public spending in various sectors is broadly consistent with "growth-maximizing", whereas increases in the central allocation of its budget among development projects, nondevelopment projects, and social and community services by cutting the center¡¯s spending on all other functions can promote regional growth. Furthermore, the distortionary effect of the state tax in India is dominated by the productive effect of tax-financed public spending, whereas the reverse holds for the central tax.
Analytical study of the bond behavior of fiber reinforced cementitious matrix (FRCM)-substrate joints based on a two-stage nonlinear cohesive material law
No full textExternally bonding fiber-reinforced cementitious matrix (FRCM) composite to the surface of concrete or masonry members is an effective technique to improve the performance of existing structures. In many cases, interfacial debonding between the FRCM fiber textile and embedding matrix governs the capacity of FRCM-strengthened structures. The interfacial debonding process can be studied analytically by assuming a cohesive material law (CML), which represents the relationship between interfacial shear stress and slip. In this study, a two-stage function with an exponential stage and a constant stage is proposed to describe the CML associated with the matrix-fiber interface. The latter stage is characterized by a constant shear stress to account for the friction/interlocking between the matrix and fiber observed in experimental tests. With the assumed CML, the full-range loading response was obtained. Additionally, the interfacial slip, fiber axial strain, and interfacial shear stress were analytically derived. The parameters of the two-stage CMLs for PBO, glass, and carbon FRCM were inversely determined by matching the analytical relationships of peak applied axial stresses associated with different bonded lengths with the experimental ones. Considering the inversely determined CMLs, the predicted load responses and strain profiles showed good agreement with the measurements of direct shear test specimens
Investigation of the bond behavior of the fiber reinforced composite-concrete interface using the finite difference method (FDM)
No full textFiber reinforced composite materials, including fiber reinforced polymer (FRP) and fiber reinforced cementitious matrix (FRCM), have been widely used to increase the load-carrying capacity and ductility of concrete structures. The bond-slip relationship of the composite-concrete interface is of pivotal significance to understand the behavior of the strengthened structure. This study presents a generic and versatile finite difference method (FDM) solution that can predict the full-range bond behavior of the composite-concrete interface adopting different (e.g., bilinear, trilinear, exponential, and their combinations) bond-slip relationships. The proposed FDM solution successfully captures the snap-back phenomenon using an arc-length method for iteration. Comparison between FDM and analytical results shows that (i) for some frequently adopted analytical solutions, the assumption of zero slip at the composite free end is not suitable for short bonded lengths and fails to capture the snap-back phenomenon and load descending stage for long bonded lengths; (ii) for bond-slip relationships with different shapes, the load responses are similar but the effective bond lengths can be different when the same fracture energy is enforced; and (iii) for composite-concrete joints with finite bonded length, the peak load may not be the same when adopting different bond-slip relationships with the same fracture energy
Zou Shuzi yi shu /
No full textEach work has special t. p.Double leaves, oriental style, in case.Blockprint.Imprint date from preface.Mode of access: Internet
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
- …
