minimum resistance
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2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sukhtaj Singh ◽  
Ezekiel Chinyio ◽  
Subashini Suresh

Purpose Project managers still face challenges with managing stakeholders. Using building information modelling (BIM) has further increased these challenges. Meanwhile, there is a paucity of research specifically focussing on the techniques which organisations are adopting to manage stakeholders within BIM-implemented projects and the associated benefits which they can reap. Thus, this paper aims to identify the key techniques, enablers and benefits of managing stakeholders within BIM-implemented projects. Design/methodology/approach An exploratory approach was adopted due to the paucity of the variables on the topic. In total, 23 semi-structured interviews were conducted in the UK through purposive and snowball sampling. The data was analysed using content analysis and the “NVivo 11 Pro” software. Findings Two key techniques and two enablers required to manage stakeholders within BIM-implemented projects were identified. Nine benefits of managing stakeholders were identified which split into interim and eventual benefits. Originality This paper provides a richer understanding of the enablers and techniques which organisations should focus on while strategising for minimum resistance from stakeholders in their BIM implemented projects.



2021 ◽  
Vol 154 (A3) ◽  
Author(s):  
M Haase ◽  
J Binns ◽  
G Thomas ◽  
N Bose ◽  
G Davidson ◽  
...  

A new class of fuel-efficient and environmentally friendly twin-hull vessels is currently under development. Compared to high-speed catamarans, a significant reduction in speed combined with an increase in deadweight tonnes will lead to a highly efficient medium-speed catamaran design. Recently-built conventional and high-speed ferries are compared to each other in terms of length, speed, deadweight and transport efficiency to classify the new design. The goal of this study is to find a preliminary macro design point for minimum total resistance by considering the main particulars of the catamaran vessel: block coefficient, prismatic coefficient and slenderness and separation ratios of the demihulls. Publications containing recommendations towards the optimum hull form parameters for moderate Froude numbers are reviewed and existing experimental data analysed to identify parameters for this new class of vessel. Designs with varied L/BOA-ratios and constant deck area are compared to find configurations of low total resistance for carrying a nominated deadweight at a particular speed, the associated change of the light ship weight has been taken into account. Two different model test series of catamaran models have been considered and their resistance curves agreed to each other. Recommendations are made; with the most important being the vessel should not exceed a speed of Fr = 0.35, with optimal prismatic coefficients around CP ≈ 0.5 and low transom immersion. This study presents the preliminary design of medium-speed single and twin-hull vessels for operations close to hump speed.



Author(s):  
Jing Zou ◽  
Kun Jin ◽  
Tongsheng Chen ◽  
Xinlei Li

Abstract When cells are cultured on the micro- or nano- structure substrate, filamentous pseudopods are formed at specific locations due to the effects of substrate morphology and local membrane curvature, which provides a powerful method to guide cell migration and neurite orientation. However, it is unclear the effects of substrate surface morphology and initial cell membrane on pseudopod formation and growth. Here, we present a quantitative thermodynamic model to investigate the difficulty of pseudopod formation. Based on the established model, we studied the effects of substrate morphology and the curvature of the initial cell membrane on filamentous pseudopods formation by analyzing the magnitude of an average driving force. We find that the pseudopod-substrate adhesion and the larger curvature radius of the initial cell membrane can facilitate filamentous pseudopods formation due to the smaller minimum resistance energy. Furthermore, our theoretical results seem to show a broad agreement with experimental observations, which implies that these studies would provide useful guidance to control the pseudopods formation on substrate for biomedical applications.





2021 ◽  
Vol 55 (6) ◽  
pp. 117-128
Author(s):  
Guan Guan ◽  
Shuai Zhou ◽  
Zhengmao Zhuang ◽  
Qu Yang

Abstract In the conventional process of parametric ship optimization, the selection of design variables mostly relies on design experience. The lack of a clear and quantitative method of parameter selection leads to a certain degree of blindness and inefficiency. In this article, a parametric hull modeling method is proposed. The sensitivity analysis based on orthogonal experimental design is performed to select the design variables of optimization. Through variance and range analysis, the parameters that have a significant influence on the optimization objective are selected as the design variables. A combination of Sobol and tangent search method is applied during the optimization. The shape optimization of a fishing boat with minimum resistance is taken as an example. The optimization result proves the efficiency of the proposed parametric modeling method and the sensitivity analysis, which are significant for the shape optimization of a fishing boat.



Author(s):  
Z. Kanavas ◽  
F. J. Pérez-Reche ◽  
F. Arns ◽  
V. L. Morales

Abstract This work aims to describe the spatial distribution of flow from characteristics of the underlying pore structure in heterogeneous porous media. Thousands of two-dimensional samples of polydispersed granular media are used to (1) obtain the velocity field via direct numerical simulations, and (2) conceptualize the pore network as a graph in each sample. Analysis of the flow field allows us to distinguish preferential from stagnant flow regions and to quantify how channelized the flow is. Then, the graph’s edges are weighted by geometric attributes of their corresponding pores to find the path of minimum resistance of each sample. Overlap between the preferential flow paths and the predicted minimum resistance path determines the accuracy in individual samples. An evolutionary algorithm is employed to determine the “fittest” weighting scheme (here, the channel’s arc length to pore throat ratio) that maximizes accuracy across the entire dataset while minimizing over-parameterization. Finally, the structural similarity of neighboring edges is analyzed to explain the spatial arrangement of preferential flow within the pore network. We find that connected edges within the preferential flow subnetwork are highly similar, while those within the stagnant flow subnetwork are dissimilar. The contrast in similarity between these regions increases with flow channelization, explaining the structural constraints to local flow. The proposed framework may be used for fast characterization of porous media heterogeneity relative to computationally expensive direct numerical simulations. Article Highlights A quantitative assessment of flow channeling is proposed that distinguishes pore-scale flow fields into preferential and stagnant flow regions. Geometry and topology of the pore network are used to predict the spatial distribution of fast flow paths from structural data alone. Local disorder of pore networks provides structural constraints for flow separation into preferential v stagnant regions and informs on their velocity contrast.



RSC Advances ◽  
2021 ◽  
Vol 11 (62) ◽  
pp. 39311-39318
Author(s):  
Abdullah Abdulhameed ◽  
Izhal Abdul Halin ◽  
Mohd Nazim Mohtar ◽  
Mohd Nizar Hamidon

Airflow-assisted dielectrophoresis (AA-DEP) is a novel dielectrophoresis (DEP) setup used to fabricate sensor devices with minimum resistance variation by assembling and aligning carbon nanotubes (CNTs) across electrode structures.



2020 ◽  
Vol 23 (4) ◽  
pp. 6p
Author(s):  
Abbas Shokri ◽  
Kousar Ramezani

Osteosarcoma is a relatively rare lesion in the maxillary bone. The proximity of the lesion to the maxillary sinus provides a null space with the minimum resistance to progress prior to manifest clinically, which makes the early diagnosis more critical. We report a case of maxillary osteosarcoma in a 21-year old male patient who was presented with the chief complaint of the pain and swelling on the left side of palate since 2 months earlier. A cone-beam computed tomography of the maxilla revealed a diffuse hyper-intense entity at the left side of the maxilla. Totally-occupied maxillary sinus space, asymmetric periodontal ligament widening of the involved teeth and spiculated and sunray periosteal reaction were recognized. The diagnosis of osteosarcoma was established and confirmed by histopathology. This article reviews the sinus-occupying lesion in the following and describes the lesions originate within the maxillary sinus or arise from the adjacent odontogenic components. Keywords Case report; Maxillary sinus; Osteosarcoma.



2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Sooraj Singh Rawat ◽  
A. P. Harsha ◽  
O. P. Khatri ◽  
Rolf Wäsche

Abstract Pristine, reduced, and alkylated graphene oxides are applied as lubricating additives in paraffin grease. It has revealed that their crystalline structure governs the tribological properties of grease for steel tribo-pair. The microstructural analyses of grease samples showed that a loose fiber network of soap in the presence of graphene-based additive allows their facile release for efficient lubrication. The surface analyses based on the microscopic and elemental mapping show the development of a graphene-derived protective film on the worn scars, which protected the tribo-surfaces and subsided the wear. The reduced graphene oxide (rGO) with the interlamellar distance of 0.35 nm in the (002) plane provided minimum resistance to shear and exhibited maximum reduction in coefficient of friction (COF) for the paraffin grease. The presence of oxygen functionalities in the basal of pristine and alkylated graphene oxide (GO) compromised the interlamellar shearing under tribo-stress; consequently, higher COF than that of rGO.



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