997 resultados para Deflection (structures)


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The structures of two hydrated proton-transfer compounds of 4-piperidinecarboxamide (isonipecotamide) with the isomeric heteroaromatic carboxylic acids indole-2-carboxylic acid and indole-3-carboxylic acid, namely 4-carbamoylpiperidinium indole-2-carboxylate dihydrate (1) and 4-carbamoylpiperidinium indole-3-carboxylate hemihydrate (2) have been determined at 200 K. Crystals of both 1 and 2 are monoclinic, space groups P21/c and P2/c respectively with Z = 4 in cells having dimensions a = 10.6811(4), b = 12.2017(4), c = 12.5456(5) Å, β = 96.000(4)o (1) and a = 15.5140(4), b = 10.2908(3), c = 9.7047(3) Å, β = 97.060(3)o (2). Hydrogen-bonding in 1 involves a primary cyclic interaction involving complementary cation amide N-H…O(carboxyl) anion and anion hetero N-H…O(amide) cation hydrogen bonds [graph set R22(9)]. Secondary associations involving also the water molecules of solvation give a two-dimensional network structure which includes weak water O-H…π interactions. In the three-dimensional hydrogen-bonded structure of 2, there are classic centrosymmetric cyclic head-to-head hydrogen-bonded amide-amide interactions [graph set R22(8)] as well as lateral cyclic amide-O linked amide-amide extensions [graph set R24(8)]. The anions and the water molecule, which lies on a twofold rotation axis, are involved in secondary extensions.

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Partially grouted wider reinforced masonry wall, built predominantly using face shell bedded hollow concrete blocks, is an economical structural system and is popularly used in the cyclonic areas; its out-of-plane response to lateral loading is well understood, unfortunately its inplane shear behaviour is less well understood as to the effect of partial gouting in intervening the load paths within the wall. For rational analysis of the wall clarification is sought as to whether the wall acts as a composite of unreinforced panels and reinforced cores or as a continuum of masonry embedded with reinforced at wider spacing. This paper reports the results of four full scale walls tested under inplane cyclic shear loading to provide some insight into the effect of the grout cores in altering the load paths within the wall. The global lateral load - lateral deflection hysteric curves as well as local responses of some critical zones of the shear walls are presented.

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Innovation processes are rarely smooth and disruptions often occur at transition points were one knowledge domain passes the technology on to another domain. At these transition points communication is a key component in assisting the smooth hand over of technologies. However for smooth transitions to occur we argue that appropriate structures have to be in place and boundary spanning activities need to be facilitated. This paper presents three case studies of innovation processes and the findings support the view that structures and boundary spanning are essential for smooth transitions. We have explained the need to pass primary responsibility between agents to successfully bring an innovation to market. We have also shown the need to combine knowledge through effective communication so that absorptive capacity is built in process throughout the organisation rather than in one or two key individuals.

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Background: In vitro investigations have demonstrated the importance of the ribcage in stabilising the thoracic spine. Surgical alterations of the ribcage may change load-sharing patterns in the thoracic spine. Computer models are used in this study to explore the effect of surgical disruption of the rib-vertebrae connections on ligament load-sharing in the thoracic spine. Methods: A finite element model of a T7-8 motion segment, including the T8 rib, was developed using CT-derived spinal anatomy for the Visible Woman. Both the intact motion segment and the motion segment with four successive stages of destabilization (discectomy and removal of right costovertebral joint, right costotransverse joint and left costovertebral joint) were analysed for a 2000Nmm moment in flexion/extension, lateral bending and axial rotation. Joint rotational moments were compared with existing in vitro data and a detailed investigation of the load sharing between the posterior ligaments carried out. Findings: The simulated motion segment demonstrated acceptable agreement with in vitro data at all stages of destabilization. Under lateral bending and axial rotation, the costovertebral joints were of critical importance in resisting applied moments. In comparison to the intact joint, anterior destabilization increases the total moment contributed by the posterior ligaments. Interpretation: Surgical removal of the costovertebral joints may lead to excessive rotational motion in a spinal joint, increasing the risk of overload and damage to the remaining ligaments. The findings of this study are particularly relevant for surgical procedures involving rib head resection, such as some techniques for scoliosis deformity correction.

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Organizations today engage in various forms of alliances to manage their existing business processes or to diversify into new processes to sustain their competitive positions. Many of today’s alliances use the IT resources as their backbone. The results of these alliances are collaborative organizational structures with little or no ownership stakes between the parties. The emergence of Web 2.0 tools is having a profound effect on the nature and form of these alliance structures. These alliances heavily depend on and make radical use of the IT resources in a collaborative environment. This situation requires a deeper understanding of the governance of these IT resources to ensure the sustainability of the collaborative organizational structures. This study first suggests the types of IT governance structures required for collaborative organizational structures. Semi-structured interviews with senior executives who operate in such alliances reveal that co-created IT governance structures are necessary. Such structures include co-created IT-steering committees, co-created operational committees, and inter-organizational performance management and communication systems. The findings paved the way for the development of a model for understanding approaches to governing IT and evaluating the effectiveness for such governance mechanisms in today’s IT dependent alliances. This study presents a sustainable IT-related capabilities approach to assessing the effectiveness of suggested IT governance structures for collaborative alliances. The findings indicate a favourable association between organizations IT governance efforts and their ability to sustain their capabilities to leverage their IT resources. These IT-related capabilities also relate to measures business value at the process and firm level. This makes it possible to infer that collaborative organizations’ IT governance efforts contribute to business value.

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Purpose: The purpose of this paper is to guide the formation and to determine the structure of new governmental entrepreneurial ventures based on the nature of the public goods and the need for an entrepreneurial orientation. Design/methodology/research: This paper is conceptual and is based on reviews of appropriate organizational structure and entrepreneurship, cases studies, and the authors' experiences. Findings: Public or quasi-public entities may need to change their organizational structure in order to act more entrepreneurially and to be more effective in accomplishing their missions. Propositions are raised to guide the development of new public or private enterprises and provide the basis for future research. Research limitations/implications: This paper is conceptual and needs to be tested empirically. Though other levels of government and countries were included, a major focus is on the US federal government. Originality/value: This is the first published research on the topic of new enterprise government structures based on the nature of the goods and the requisite entrepreneurial orientation. It will help governmental and quasi-governmental organizations in developing efficient and effective organizational structures.

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The demands of taller structures are becoming imperative almost everywhere in the world in addition to the challenges of material and labor cost, project time line etc. This paper conducted a study keeping in view the challenging nature of high-rise construction with no generic rules for deflection minimizations and frequency control. The effects of cyclonic wind and provision of outriggers on 28-storey, 42-storey and 57-storey are examined in this paper and certain conclusions are made which would pave way for researchers to conduct further study in this particular area of civil engineering. The results show that plan dimensions have vital impacts on structural heights. Increase of height while keeping the plan dimensions same, leads to the reduction in the lateral rigidity. To achieve required stiffness increase of bracings sizes as well as introduction of additional lateral resisting system such as belt truss and outriggers is required.

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The LiteSteel Beam (LSB) is a new hollow flange channel section developed using a patented dual electric resistance welding and cold-forming process. It has a unique geometry consisting of torsionally rigid rectangular hollow flanges and a slender web, and is commonly used as flexural members. However, the LSB flexural members are subjected to a relatively new lateral distortional buckling mode, which reduces their moment capacities. Unlike lateral torsional buckling, the lateral distortional buckling of LSBs is characterised by simultaneous lateral deflection, twist and cross sectional change due to web distortion. Therefore a detailed investigation into the lateral buckling behaviour of LSB flexural members was undertaken using experiments and finite element analyses. This paper presents the details of suitable finite element models developed to simulate the behaviour and capacity of LSB flexural members subject to lateral buckling. The models included all significant effects that influence the ultimate moment capacities of such members, including material inelasticity, lateral distortional buckling deformations, web distortion, residual stresses, and geometric imperfections. Comparison of elastic buckling and ultimate moment capacity results with predictions from other numerical analyses and available buckling moment equations, and experimental results showed that the developed finite element models accurately predict the behaviour and moment capacities of LSBs. The validated model was then used in a detailed parametric study that produced accurate moment capacity data for all the LSB sections and improved design rules for LSB flexural members subject to lateral distortional buckling.

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The LiteSteel Beam (LSB) is a new hollow flange channel section developed by OneSteel Australian Tube Mills using its patented dual electric resistance welding and automated continuous roll-forming technologies. The LSB has a unique geometry consisting of torsionally rigid rectangular hollow flanges and a relatively slender web. Its flexural strength for intermediate spans is governed by lateral distortional buckling characterised by simultaneous lateral deflection, twist and web distortion. Recent research on LSBs has mainly focussed on their lateral distortional buckling behaviour under uniform moment conditions. However, in practice, LSB flexural members are subjected to non-uniform moment distributions and load height effects as they are often under transverse loads applied above or below their shear centre. These loading conditions are known to have significant effects on the lateral buckling strength of beams. Many steel design codes have adopted equivalent uniform moment distribution and load height factors based on data for conventional hot-rolled, doubly symmetric I-beams subject to lateral torsional buckling. The non-uniform moment distribution and load height effects of transverse loading on cantilever LSBs, and the suitability of the current design modification factors to include such effects are not known. This paper presents a numerical study based on finite element analyses of the elastic lateral buckling strength of cantilever LSBs subject to transverse loading, and the results. The applicability of the design modification factors from various steel design codes was reviewed, and suitable recommendations are presented for cantilever LSBs subject to transverse loading.

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Organizations today engage in various forms of alliances to manage their existing business processes or to diversify into new processes to sustain their competitive positions. Many of today’s alliances use the IT resources as their backbone. The results of these alliances are collaborative organizational structures with little or no ownership stakes between the parties. The emergence of Web 2.0 tools is having a profound effect on the nature and form of these alliance structures. These alliances heavily depend on and make radical use of the IT resources in a collaborative environment. This situation requires a deeper understanding of the governance of these IT resources to ensure the sustainability of the collaborative organizational structures. This study reports on the first stage of this initiative. It suggest the types of IT governance structures required for collaborative organizational structures. Semi-structured interviews with senior executives who operate in such alliances reveal that co-created IT governance structures are necessary. Such structures include co-created IT-steering committees, cocreated operational committees, and inter-organizational performance management and communication systems. The findings pave the way for the development of a model for understanding approaches to governing IT and evaluating the effectiveness for such governance mechanisms in today’s IT dependent alliances.

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The IT systems drive the financial reporting processes in modern business environments. The result is an integrative system of initialing, authorizing, recording, and processing of financial transactions. This IT-related change inextricably links to the overall financial reporting process, requiring a deeper level of understanding and commitment. Firm’s IT governance initiatives provide this commitment by enforcing controls to IT components to ensure compliance to overall financial reporting requirements. The IT governance institute (ITGI) and other authorities have developed a number of frameworks and guidelines (e.g., COBIT) to help management in managing IT-intensive processes.

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Sandwich shells have recently emerged as aesthetically pleasing, efficient and economical structural systems, with a number of applications. They combine the advantages of sandwich layer technology together with those of shell action. With different materials and thicknesses used in the sandwich layers, their performance characteristics largely remain un-quantified and there are no guidelines at present for their design. This research paper provides verification, through finite element modeling and testing, for the application of this technology to dome styled dwellings with research currently being conducted into the further application to roofing and floor structures.

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Gender identity-conscious HR structures signal an organization’s perspective on gender diversity. The signal produces perceptions that the organization values gender diversity leading to a gender diverse workforce. In turn, a gender diverse workforce provides a firm with a competitive advantage which should result in higher performance. This paper tests the mediating effects of gender diversity (at non-management and management levels) in the relationship between gender identity-conscious HR structures and performance. The findings indicate that non-management gender diversity partially mediates the relationship between HR structures and productivity, and management gender diversity partially mediates the relationship between HR structures and perceived market performance.