1,648 research outputs found
Development of Arm Exo-skeleton for Bicep Brachii Muscle
This report presents the study on design of arm exoskeleton for stroke rehabilitation purpose. The mechanical design of the exoskeleton focuses on few aspects of the arm exoskeleton which are length and the design of the exoskeleton and motor specification. Besides, the experiment of obtaining surface electromyography (sEMG) signal for repetition training for physiotherapy patient purpose is carried out to observe the difference in amplitude and muscle signal of different subjects (four males and four females) due to the amount of training and the angle of the training. The signals are filtered and the average of the root mean square of the data is compared
Micromechanics model for predicting effective elastic moduli of porous ceramic matrices with randomly oriented carbon nanotube reinforcements
Multi-step micromechanics-based models are developed to predict the overall effective elastic moduli of porous ceramic with randomly oriented carbon nanotube (CNT) reinforcements. The presence of porosity in the ceramic matrix that has been previously neglected in the literature is considered in present analysis. The ceramic matrix with porosity is first homogenized using a classical Mori-Tanaka model. Then, the homogenized porous ceramic matrix with randomly oriented CNTs is analysed using two micromechanics models. The results predicted by the present models are compared with experimental and analytical results that have been reported in literature. The comparison shows that the discrepancies between the present analytical results and experimental data are about 10% for 4 wt% of CNTs and about 0.5% for 8 wt% CNTs, both substantially lower than the discrepancies currently reported in the literature
Modelling powder-binder segregation in powder injection moulding
Powder injection moulding (PIM) is a shape forming technique for advance ceramic or metal that allows low cost and complex shape manufacturing. The segregation between powder and binder is a common occurrence during PIM which leads to the inhomogeneity in the green bodies. A multiphase flow numerical model has been developed based on Eulerian approach to simulate this phenomenon in the injection stage of silicon nitride-based ceramics. A viscosity model based on experimental data of the feedstock is employed in the numerical model. Simulated results from the numerical model have been compared with experimental results. A powder distribution analysis is compared with density distribution test of the green bodies with similar process parameters and flow trends is compared experimental short shots
Powder distribution on powder injection moulding of ceramic green compacts using thermogravimetric analysis and differential scanning calorimetry
Powder-binder separation during injection moulding causes defects such as cracking, warpage or anisotropic shrinkage during firing. In this paper, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) that were previously used to analyse powder distribution within the green body for metal injection moulding are used for ceramics. TGA and DSC are used to characterize the mass loss and heat of fusion of the binder system, silicon nitride feedstock and test-bars. TGA can measure the volume fraction of powder in green parts directly with 1.76 vol% difference from nominal volume fraction and variations up to 0.177 vol%. The DSC empirical model predicted volume fraction of powder in green parts with 1.76 vol% difference from nominal volume fraction and variations up to 1.710 vol%. Using rule of mixture, it over predicted volume fraction of powder in green parts by 6.78 vol% from nominal volume fraction and with variations up to 2.510 vol%
The Role of Weight on Community Structure of Networks
The role of weight on the weighted networks is investigated by studying the
effect of weight on community structures. We use weighted modularity to
evaluate the partitions and Weighted Extremal Optimization algorithm to detect
communities. Starting from idealized and empirical weighted networks, the
distribution or matching between weights and edges are disturbed. Using
dissimilarity function to distinguish the difference between community
structures, it is found that the redistribution of weights does strongly affect
the community structure especially in dense networks. This indicates that the
community structure in networks is a suitable property to reflect the role of
weight.Comment: 10 pages, 6 figure
Modelling powder-binder segregation in powder injection moulding
Powder injection moulding (PIM) is a shape forming technique for advance ceramic or metal that allows low cost and complex shape manufacturing. The segregation between powder and binder is a common occurrence during PIM which leads to the inhomogeneity in the green bodies. A multiphase flow numerical model has been developed based on Eulerian approach to simulate this phenomenon in the injection stage of silicon nitride-based ceramics. A viscosity model based on experimental data of the feedstock is employed in the numerical model. Simulated results from the numerical model have been compared with experimental results. A powder distribution analysis is compared with density distribution test of the green bodies with similar process parameters and flow trends is compared experimental short shots
Effective-stress finite element analysis of spudcan penetration with lattice leg in clay
10.1063/1.4826009AIP Conference Proceedings15582337-234
Network of Econophysicists: a weighted network to investigate the development of Econophysics
The development of Econophysics is studied from the perspective of scientific
communication networks. Papers in Econophysics published from 1992 to 2003 are
collected. Then a weighted and directed network of scientific communication,
including collaboration, citation and personal discussion, is constructed. Its
static geometrical properties, including degree distribution, weight
distribution, weight per degree, and betweenness centrality, give a nice
overall description of the research works. The way we introduced here to
measure the weight of connections can be used as a general one to construct
weighted network.Comment: 6 pages, 7 figure
Validation of a rapid and sensitive LC-MS/ MS method for determination of exemestane and its metabolites, 17β-hydroxyexemestane and 17β-hydroxyexemestane-17-O-β-D-glucuronide: Application to human pharmacokinetics study
10.1371/journal.pone.0118553PLoS ONE103e011855
- …