What makes an accurate and reliable subject-specific finite element model? A case study of an elephant femur

Finite element modelling is well entrenched in comparative vertebrate biomechanics as a tool to assess the mechanical design of skeletal structures and to better comprehend the complex interaction of their form–function relationships. But what makes a reliable subject-specific finite element model? To approach this question, we here present a set of convergence and sensitivity analyses and a validation study as an example, for finite element analysis (FEA) in general, of ways to ensure a reliable model. We detail how choices of element size, type and material properties in FEA influence the results of simulations. We also present an empirical model for estimating heterogeneous material properties throughout an elephant femur (but of broad applicability to FEA). We then use an ex vivo experimental validation test of a cadaveric femur to check our FEA results and find that the heterogeneous model matches the experimental results extremely well, and far better than the homogeneous model. We emphasize how considering heterogeneous material properties in FEA may be critical, so this should become standard practice in comparative FEA studies along with convergence analyses, consideration of element size, type and experimental validation. These steps may be required to obtain accurate models and derive reliable conclusions from them.     

What makes a journal international? A case study using conservation biology journals

The qualitative label ‘international journal’ is used widely, including in national research quality assessments. We determined the practicability of analysing internationality quantitatively using 39 conservation biology journals, providing a single numeric index (IIJ) based on 10 variables covering the countries represented in the journals’ editorial boards, authors and authors citing the journals’ papers. A numerical taxonomic analysis refined the interpretation, revealing six categories of journals reflecting distinct international emphases not apparent from simple inspection of the IIJs alone. Categories correlated significantly with journals’ citation impact (measured by the Hirsch index), with their rankings under the Australian Commonwealth’s ‘Excellence in Research for Australia’ and with some countries of publication, but not with listing by ISI Web of Science. The assessments do not reflect on quality, but may aid editors planning distinctive journal profiles, or authors seeking appropriate outlets.     

Modelling and comparative study of viscoelastic laminated composite beam – an operator based finite element approach

Mechanics of Time-Dependent Materials - Finite element formulation of damped laminated composite beam considering both Euler-Bernoulli and Timoshenko beam theory is proposed based on Equivalent...     

What makes a scientific article influential? The case of demographers

In this paper we examine, by means of a citation analysis, which factors influence the impactof articles published in demography journals between 1990 and 1992. Several quantifiablecharacteristics of the articles (characteristics with respect to authors, visibility, content andjournals) are strongly related to their subsequent impact in the social sciences. Articles are mostfrequently cited when they deal with empirical, ahistorical research focusing on populations in thedeveloped world, when they are prominently placed in a journal issue, when they are written inEnglish and when they appear in core demography journals. Furthermore, although eminentscholars are likely to be cited on the basis of their reputation, the effect of reputation appears to besmall in demography.     

What makes a successful industry-level catch-up? General framework and case study of China’s LED industry

How latecomers from emerging countries catch up on technological innovation is an important topic for industrial practitioners, policymakers, and academic researchers. This study systematically reviews 37 empirical studies on the precursors of industry catch-up in emerging countries. A general framework on what makes a successful catch-up in latecomer industries is suggested based on literature review. The framework comprises six generic determinants, including technological capability, business ecosystem, government roles, market condition, technological regime, and windows of opportunity. In addition, this framework is applied to the Chinese LED industry, and a case analysis of the catch-up is performed in Chinese LED firms.     

The protective effect of a helmet in three bicycle accidents—A finite element study

There is some controversy regarding the effectiveness of helmets in preventing head injuries among cyclists. Epidemiological, experimental and computer simulation studies have suggested that helmets do indeed have a protective effect, whereas other studies based on epidemiological data have argued that there is no evidence that the helmet protects the brain. The objective of this study was to evaluate the protective effect of a helmet in single bicycle accident reconstructions using detailed finite element simulations.Strain in the brain tissue, which is associated with brain injuries, was reduced by up to 43% for the accident cases studied when a helmet was included. This resulted in a reduction of the risk of concussion of up to 54%. The stress to the skull bone went from fracture level of 80 MPa down to 13–16 MPa when a helmet was included and the skull fracture risk was reduced by up to 98% based on linear acceleration. Even with a 10% increased riding velocity for the helmeted impacts, to take into account possible increased risk taking, the risk of concussion was still reduced by up to 46% when compared with the unhelmeted impacts with original velocity. The results of this study show that the brain injury risk and risk of skull fracture could have been reduced in these three cases if a helmet had been worn.     

What makes an article influential? Predicting impact in social and personality psychology

Factors contributing to citation impact in social-personality psychology were examined in a bibliometric study of articles published in the field’s three major journals. Impact was operationalized as citations accrued over 10 years by 308 articles published in 1996, and predictors were assessed using multiple databases and trained coders. Predictors included author characteristics (i.e., number, gender, nationality, eminence), institutional factors (i.e., university prestige, journal prestige, grant support), features of article organization (i.e., title characteristics, number of studies, figures and tables, number and recency of references), and research approach (i.e., topic area, methodology). Multivariate analyses demonstrated several strong predictors of impact, including first author eminence, having a more senior later author, journal prestige, article length, and number and recency of references. Many other variables — e.g., author gender and nationality, collaboration, university prestige, grant support, title catchiness, number of studies, experimental vs. correlational methodology, topic area — did not predict impact.     

What factors are associated with increasing co-authorship in the social sciences? A case study of Danish Economics and Political Science

We examine the relative strength of short-term citation counts, bibliometric measures such as journal impact factors, and journal rankings in terms of predicting long-run citations. Using a set of articles published in sixty of the highest reputation economics journals in 1994, we find that citations received over fairly short windows (between 1 and 2 years after publication) are much stronger predictors of long-run citation counts compared with journal impact factors or other journal rankings. Our results are robust to a series of robustness checks. These findings suggest department heads and tenure and promotion committees should place greater weight on short-term citations as opposed to article placement when making personnel decisions.     

A study of the geogrid–subballast interface via experimental evaluation and discrete element modelling

This paper presents a study of the interface of geogrid reinforced subballast through a series of large-scale direct shear tests and discrete element modelling. Direct shear tests were carried out for subballast with and without geogrid inclusions under varying normal stresses of \(\sigma _n =6.7\) to \(45\hbox { kPa}\). Numerical modelling with three-dimensional discrete element method (DEM) was used to study the shear behaviour of the interface of subballast reinforced by geogrids. In this study, groups of 25–50 spherical balls are clumped together in appropriate sizes to simulate angular subballast grains, while the geogrid is modelled by bonding small spheres together to form the desired grid geometry and apertures. The calculated results of the shear stress ratio versus shear strain show a good agreement with the experimental data, indicating that the DEM model can capture the interface behaviour of subballast reinforced by geogrids. A micromechanical analysis has also been carried out to examine how the contact force distributions and fabric anisotropy evolve during shearing. This study shows that the shear strength of the interface is governed by the geogrid characteristics (i.e. their geometry and opening apertures). Of the three types of geogrid tested, triaxial geogrid (triangular apertures) exhibits higher interface shear strength than the biaxial geogrids; and this is believed due to multi-directional load distribution of the triaxial geogrid.     

Would relaxing speed limits aggravate safety? A case study of Hong Kong

This paper studies the effect of the changed speed limits on accident counts for major roadways in the urban environment of Hong Kong. In 1999-2002, the speed limits of a number of sections of roadway were reviewed and increased. Nineteen of them were major roadways. Their speed limits were raised by 10-20 km/h from 50 to 70 km/h. Before and after studies were carried out to investigate the changes in accident counts with respect to the set of carefully chosen comparison groups. Qualification tests for these comparison groups were conducted to confirm their suitability for the studies. In the majority of the treatment sites, the accident counts were worse after the increase in speed limits, both for the category of fatal, serious and slight (FSS) accidents, and for the category of fatal and serious (FS) accidents. Overall, the relaxation of the speed limit from 50 to 70 km/h increased the FSS accident counts by 15% and the FS accident counts by 1%. The relaxation of the speed limit from 70 to 80 km/h increased the FSS accident counts by 18% and the FS accident counts by 36%.     

A study of the spatial distribution of transportation‐an alternative approach and evaluation

Abstract

This study intends to investigate a calibration procedure for a proposed combined trip generation and distribution model which is based on the concept of accessibility. Apart from the proofs of the existence and uniqueness of the solution, the computation efficiency is evaluated by using Cesario's data (1). The calibration procedure is further tested with empirical data which is obtained from an actual transportation survey carried out in Kaohsiung City of Taiwan, the Republic of China.     

Is rigorous punishment effective? A case study of lifetime license revocation in Taiwan

This study investigated the effectiveness of administrative lifetime driver's license revocation (ALLR) and its impact on offenders, based on a two-stage survey of 768 offenders. It was found that after ALLR had been imposed, 23.4% of these offenders were still driving almost the same as before, 59.8% drove significantly less frequently, and only 16.8% of the offenders gave up driving completely. The results of logistic regression models showed that offenders' compliance with ALLR was significantly correlated with their personal characteristics (age, income), penalty status (incarceration, duration of ALLR), and the need to drive for working, commuting and shopping. Elderly and low-income offenders were more likely to abide by the ALLR restriction. The application of the generalized estimating equations (GEE) model was used to identify the determinant factors affecting offenders' driving mileage, and to effectively estimate the driving mileage reduction as a result of the ALLR. It was found that ALLR is fairly effective in keeping offenders off the road, but that it may reduce their ability to make a living, resulting in the less fortunate becoming more helpless.     

Characterizing the intrinsic properties of powder – A combined discrete element analysis and Hall flowmeter testing study

Discrete element modelling (DEM) and experimental characterization were carried out for Hall flowmeter tests, in which Inconel718 powders were poured down through a funnel into a density cup to form a heap. By measuring the flow rate, angle of repose and packing fraction from the experiments, and combining with DEM simulations, we were able to extract the coefficients of friction for the powder-powder and powder-wall interactions. We further studied the effect of powder-powder adhesion and found that the adhesion could greatly affect the flow rate and flow pattern. In particular, by increasing the adhesion, we observed a transition from a continuous to discontinuous discharging flow, and revealed an underlying mechanism for the transition. We also studied the effects of powder size and density cup diameter, and found that at their application size scale, the influences of these parameters on the measured results are negligible. The present work presents a simple approach to study the intrinsic properties of powders, and their influences on flowability and packing property.     

Coupling or lock-in? Co-evolution of cultural embeddness and cluster innovation-exploratory case study of Shaoxing textile cluster

Based on an exploratory case study of the development of Shaoxing textile cluster for more than 30 years, through the cross-level and multi-dimensional deconstruction of cultural embeddednesss(CE), this article dynamically analyzes the co-evolution relationship and results of its effect on the innovation capabilities of the cluster. The case study results show that CE affects the network structure and network behavior of cluster firms, which leads to the differences of innovation capabilities between cluster firms and the overall clusters. There exists a co-evolution relationship between CE and cluster innovation capabilities, and the result will lead to co-evolution coupling or lock-in. Co-evolution coupling appears in the early stage of cluster development; while co-evolution lock-in appears in the later stage of cluster development. So the embeddedness of same regional cultures may have completely different roles at different stages of cluster development. The root cause is that the network structure and behavior influenced by CE cannot dynamically match the demands for innovation in different stages of cluster's development, and the path dependence of CE evolution leads to change difficultly.     

A finite sliding model of two identical spheres under displacement and force control—part I: static analysis

A simplified analytical model of tangential contact engagement, sliding and separation of two elastic, identical spheres is developed assuming the kinematically induced sphere motion trajectory or load controlled sliding motion. The evaluation of driving force during contact sliding motion is determined for both monotonic and reciprocal sliding motion. The analytical formulae and diagrams of driving force versus sliding path are specified for linear and circular paths. The sliding trajectories are also determined for the load controlled programs. The results presented can be applied in the experimental testing of frictional response of contacting bodies, in a wear study of rough surfaces or in the contact interaction analysis of granular material during flow. The results can also be relevant for the development of the discrete element method widely applied in simulation of granular material flow, where the sliding regime conditions prevail in grain contact interaction.     

Construction and evaluation of gold standards for patent classification—A case study on quantum computing

This article discusses options for evaluation of patent and/or patent family classification algorithms by means of “gold standards”. It covers the creation criteria, and desirable attributes of evaluation mechanisms, then proposes an example gold standard, and discusses the results of applying the evaluation mechanism against the proposed gold standard and an existing commercial implementation.     

Does the higher citation of collaborative research differ from region to region? A case study of Economics

Many studies have found that collaborative research is, in general, more highly cited than non-collaborative research. This paper describes an investigation into the extent to which the association between high citation and collaboration for Economics articles published in 2000 varies from region to region and depends on the choice of indicator of citation level. Using data from the Social Science Citation Index (SSCI) for 18 countries, 17 American states and four indicators of citation level the citation levels of the collaborative articles are compared with the citation levels of the non-collaborative articles. The main findings are that: (a) for every country and every indicator the mean citation level of the collaborative articles was at least as high as that for the non-collaborative articles, but for five US states and for at least one other indicator the citation level of collaborative articles was lower than that of non-collaborative articles, and (b) the extent to which collaborative articles were more highly cited varied considerably from country to country, from state to state, and from indicator to indicator. This indicates the importance of using multiple indicators when investigating citation advantage since the choice of indicator can change the results.     

How to investigate the historical roots and evolution of research fields in China? A case study on iMetrics using RootCite

Scientometrics - This paper aimed to provide an approach to investigate the historical roots and evolution of research fields in China by extending the reference spectroscopy year spectroscopy...