Search results for "Frame"
showing 10 items of 1767 documents
Bounds on transient phase plastic deformations in optimal design of steel frames subjected to cyclic loads
2009
A minimum volume multicriterion design of elastic perfectly plastic steel frames subjected to a combination of quasi-static fixed and cyclic loads, bounding the transient phase plastic deformations, is proposed. The problem is formulated according to a plastic shakedown criterion, so that incremental and instantaneous collapse are certainly prevented when the frame is subjected to very strongly amplified cyclic loads. The further condition that the structure must also behave elastically in serviceability conditions is imposed. Since the steady-state loading history is known it is possible to directly bound the steady-state plastic deformations. By applying a suitable own bounding theorem, i…
Fixed strength and stiffness hinges for steel frames
2017
A new type of device able to connect steel beam elements is proposed. Specifically, the device is designed in such a way that the required bending stiffness and limit resistance can be independently imposed. To this goal, the device is realized as a "sandwich" section whose wings possess a particular geometry able to guarantee the required characteristics. Further technological requirement is that the device has to engage plan dimensions equal to those of the elements to which it is connected. The procedure to design the device is presented in the paper with reference to a simple plane steel portal constituted by appropriate profiles in such a way it behaves following an assigned force/disp…
Optimal design of steel frames accounting for buckling
2013
A formulation of a special design problem devoted to elastic perfectly plastic steel frame structures subjected to different combinations of static and dynamic loads is presented. In particular, a minimum volume design problem formulation is presented and the structure is designed to be able to elastically behave for the assigned fixed loads, to elastically shakedown in presence of serviceability load conditions and to prevent the instantaneous collapse for suitably chosen combinations of fixed and ultimate seismic loadings as well as of fixed and wind actions. The actions that the structure must suffer are evaluated by making reference to the actual Italian seismic code. The dynamic respon…
Deformable object segmentation in ultra-sound images
2013
Breast cancer is the second most common type of cancer being the leading cause of cancer death among females both in western and in economically developing countries. Medical imaging is key for early detection, diagnosis and treatment follow-up. Despite Digital Mammography (DM) remains the reference imaging modality, Ultra-Sound (US) imaging has proven to be a successful adjunct image modality for breast cancer screening, specially as a consequence of the discriminative capabilities that US offers for differentiating between solid lesions that are benign or malignant. Despite US usability,US suffers inconveniences due to its natural noise that compromises the diagnosis capabilities of radio…
Tonoplast intrinsic proteins from cauliflower (Brassica oleracea L. var. botrytis): immunological analysis, cDNA cloning and evidence for expression …
1998
The vacuolar membrane (tonoplast) of plant cells contains aquaporins, protein channels that facilitate the selective transport of water. These tonoplast intrinsic proteins (TIPs) of 23-29 kDa belong to the ancient major intrinsic protein (MIP) family. A monospecific polyclonal antiserum directed against a 26 kDa intrinsic protein from the tonoplast of meristematic cells from cauliflower (Brassica oleracea L. var. botrytis) was used to screen a cDNA library. Two distinct cDNAs have been isolated. Both clones, c26-1 and c26-2, encode closely related TIPs. The c26-1 insert, consisting of 933 bp upstream of the poly(A) tail, is a full-length cDNA with an open reading frame encoding a protein of…
Synthesis of rigid ethynyl-bridged polytopic picolinate ligands for MOF applications
2015
Abstract Segmented homopolytopic ligands that consist of a rigid central arylene platform, ethynylene spacers, and terminal chelating picolinate subunits have been synthesized in good yields in a two-step procedure involving a Sonogashira-type cross coupling reaction between the ester methyl 5-bromopyridine-2-carboxylate and several arylacetylenes, followed by hydrolysis of the resulting methyl picolinates. A similar strategy has been employed for the preparation of heteroditopic ligands containing picolinate and a second non-chelating pyridine or benzoate unit. The compounds are potential candidates for organic linkers in metal–organic frameworks (MOFs).
Metal-Organic Frameworks as Unique Platforms to Gain Insight of σ-Hole Interactions for the Removal of Organic Dyes from Aquatic Ecosystems.
2022
The combination of high crystallinity and rich host-guest chemistry in metal-organic frameworks (MOFs), have situated them in an advantageous position, with respect to traditional porous materials, to gain insight on specific weak noncovalent supramolecular interactions. In particular, sulfur σ-hole interactions are known to play a key role in the biological activity of living beings as well as on relevant molecular recognitions processes. However, so far, they have been barely explored. Here, we describe both how the combination of the intrinsic features of MOFs, especially the possibility of using single-crystal X-ray crystallography (SCXRD), can be an extremely valuable tool to gain insi…
Incorporation of metal-organic framework amino-modified MIL-101 into glycidyl methacrylate monoliths for nano LC separation.
2018
Metal-organic frameworks consisting of amino-modified MIL-101(M: Cr, Al, and Fe) crystals have been synthesized and subsequently incorporated to glycidyl methacrylate monoliths to develop novel stationary phases for nano-liquid chromatography. Two incorporation approaches of these materials in monoliths were explored. The metal-organic framework materials were firstly attached to the pore surface through reaction of epoxy groups present in the parent glycidyl methacrylate-based monolith. Alternatively, NH2 -MIL-101(M) were admixed in the polymerization mixture. Using short time UV-initiated polymerization, monolithic beds with homogenously dispersed metal-organic frameworks were obtained. T…
Water oxidation catalyzed by molecular di- and nonanuclear Fe complexes: importance of a proper ligand framework.
2016
The synthesis of two molecular iron complexes, a dinuclear iron(III,III) complex and a nonanuclear iron complex, based on the di-nucleating ligand 2,2-(2-hydroxy-5-methyl-1,3-phenylene)bis(1H-benzo[d]imidazole-4-carboxylic acid) is described. The two iron complexes were found to drive the oxidation of water by the one-electron oxidant [Ru(bpy)(3)](3+). Funding Agencies|Knut and Alice Wallenberg Foundation; Swedish Research Council [621-2013-4872]; Carl Trygger Foundation; DFG (Metal Sites in Biomolecules: Structures, Regulation and Mechanisms) [IRTG 1422]; Swedish Energy Agency
The effect of organizational culture on deviant behaviors in the workplace
2017
This study investigated the impact of organizational culture (OC) on deviant behaviors in the workplace (workplace deviant behaviors: WDB). We tested the hypothesis that different types of OC (according to the Competing Values Framework model) had an impact on WDB, in addition to the effect of Big Five personality traits. Survey research was undertaken with 954 employees of 30 enterprises in the public and private field, using a hierarchical model approach (HLM) to test the effects of four types of OC (Clan; Adhocracy; Market, Hierarchy) on WDB, over and above the effect of Five Personality traits. The HLM results partially supported our hypotheses, showing that the OC had a significant eff…