Correction to: How the analysis of transitionary references in knowledge networks and their centrality characteristics helps in understanding the genesis of growing technology areas

Scientometrics - In the original publication of the article, the project ID was published incorrectly in the Acknowledgements section. The correct Acknowledgement is given in this correction.     

Correction to: EM-index: a new measure to evaluate the scientific impact of scientists

Scientometrics - In the original publication, Acknowledgements was published with incomplete information. The complete Acknowledgements is given in this correction.     

Correction to: Year based EM-index: a new approach to evaluate the scientific impact of scholars

Scientometrics - In the original publication, Acknowledgements was published with incomplete information. The complete Acknowledgements is given in the correction.     

James Clerk Maxwell 150 years on

This paper is the preface to a special Issue of Phil. Trans. R. Soc. A reporting selected proceedings of the international conference marking the 150th anniversary of James Clerk Maxwell's professorial debut at Marischal College, Aberdeen. Following an introduction to Marischal College, a brief historical note summarizes Maxwell's life prior to his entering the college as professor of natural philosophy. The preface provides a short summary of the event and overviews the contributed papers devoted to subjects covering a wide range of Maxwell's research interests and their modern developments. The mixture of review and research papers reflects both the fundamental importance and the diverse applicability of Maxwell's works in electromagnetics, colour science, dynamics and kinetics. Acknowledgements are given to the individuals and bodies who made the conference the success that it was.     

Correction to: Internal migration of scientists in Russia and the USA: the case of physicists

Scientometrics - The original article was published without an acknowledgment section. The complete acknowledgment section is given below.     

Jesuit Science After Galileo: The Cosmology of Gabriele Beati

Abstract.   Gabriele Beati (1607–1673) taught mathematics at the Collegio Romano when in 1662 he published an introduction to astronomy, the Sphaera triplex . This little work contains an interesting cosmic section which is analyzed here as representing a fusion of Jesuit traditions in cosmology achieved by Giovanni Battista Riccioli (1598–1671). The cosmic section enumerates three heavens, depicts fluid planetary heavens, and expresses hexameral biblical idiom. Woodcut and engraved variants of the cosmic section offer a glimpse of Jesuit freedom to experiment with various cosmological systems (Capellan, Tychonic and semi-Tychonic). Analysis of this cosmic section suggests several conclusions for the interpretation of visual representations, science and biblical interpretation, the Scientific Revolution and Jesuit science after Galileo.     

Hydroxylapatite nanoparticles: fabrication methods and medical applications

Abstract

Hydroxylapatite (or hydroxyapatite, HAp) exhibits excellent biocompatibility with various kinds of cells and tissues, making it an ideal candidate for tissue engineering, orthopedic and dental applications. Nanosized materials offer improved performances compared with conventional materials due to their large surface-to-volume ratios. This review summarizes existing knowledge and recent progress in fabrication methods of nanosized (or nanostructured) HAp particles, as well as their recent applications in medical and dental fields. In section 1, we provide a brief overview of HAp and nanoparticles. In section 2, fabrication methods of HAp nanoparticles are described based on the particle formation mechanisms. Recent applications of HAp nanoparticles are summarized in section 3. The future perspectives in this active research area are given in section 4.     

Hydroxylapatite nanoparticles: fabrication methods and medical applications

Hydroxylapatite (or hydroxyapatite, HAp) exhibits excellent biocompatibility with various kinds of cells and tissues, making it an ideal candidate for tissue engineering, orthopedic and dental applications. Nanosized materials offer improved performances compared with conventional materials due to their large surface-to-volume ratios. This review summarizes existing knowledge and recent progress in fabrication methods of nanosized (or nanostructured) HAp particles, as well as their recent applications in medical and dental fields. In section 1, we provide a brief overview of HAp and nanoparticles. In section 2, fabrication methods of HAp nanoparticles are described based on the particle formation mechanisms. Recent applications of HAp nanoparticles are summarized in section 3. The future perspectives in this active research area are given in section 4.     

Automated section speed control on motorways: An evaluation of the effect on driving speed

Automated section speed control is a fairly new traffic safety measure that is increasingly applied to enforce speed limits. The advantage of this enforcement system is the registration of the average speed at an entire section, which would lead to high speed limit compliances and subsequently to a reduction in the vehicle speed variability, increased headway, more homogenised traffic flow and increased traffic capacity. However, the number of studies that analysed these effects are limited. The present study evaluates the speed effect of two section speed control systems in Flanders, Belgium. Both sections are located in the opposite direction of a three-lane motorway with a posted speed limit of 120 km/h. Speed data were collected at different points: from 6 km before the entrance of the section to 6 km downstream from the section. The effect was analysed through a before- and after comparison of travel speeds. General time trends and fluctuations were controlled through the analysis of speeds at comparison locations. On the enforced sections considerable decreases were found of about 5.84 km/h in the average speed, 74% in the odds of drivers exceeding the speed limit and 86% in the odds of drivers exceeding the speed limit by more than 10%. At the locations up- and downstream from the section also favourable effects were found for the three outcomes. Furthermore a decrease in the speed variability could be observed at all these data points.     

Risk perception and risk management: on knowledge, resource allocation and equity

This article is an outgrowth of the opening article given at a pair of invited sessions on “Risk Perception versus Risk Analysis” at the PSAM 3 Conference held on Crete in June 1996. The first introductory section provides some review of the relevant issues and raises some general questions about possible changes in the emphasis and directions of research on risk perception and related social science studies. The second section looks in a little more detail at issues related to public participation in the deliberations and decision-making concerning significant societal ventures involving risk. Section 3 examines the role and importance of knowledge in risk perception. the relatively brief fourth section raises questions about the public's perception of geologic disposal of high-level radioactive wastes as something catastrophic, to be “dreaded”. Section 5 looks at the bases for allocation of resources for improving the public health and safety. And the sixth section examines intragenerational equity and the conflict which can arise between it and intergenerational equity.     

Biomaterials in cardiac tissue engineering: Ten years of research survey

Driven by enormous clinical need, myocardial tissue engineering has become a prime focus of research within the field of tissue engineering. Myocardial tissue engineering combines isolated functional cardiomyocytes and a biodegradable or nondegradable biomaterial to repair diseased heart muscle. The challenges in heart muscle engineering include cell related issues (such as scale up in a short timeframe, efficiency of cell seeding or cell survival rate, and immune rejection), the design and fabrication of myocardial tissue engineering substrates, and the engineering of tissue constructs in vitro and in vivo. Several approaches have been put forward, and a number of models combining various polymeric biomaterials, cell sources and bioreactors have been developed in the last 10 years for myocardial tissue engineering. This review provides a comprehensive update on the biomaterials, as well as cells and biomimetic systems, used in the engineering of the cardiac muscle. The article is organized as follows. A historic perspective of the evolution of cardiac medicine and emergence of cardiac tissue engineering is presented in the first section. Following a review on the cells used in myocardial tissue engineering (second section), the third section presents a review on biomaterials used in myocardial tissue engineering. This section starts with an overview of the development of tissue engineering substrates and goes on to discuss the selection of biomaterials and design of solid and porous substrates. Then the applications of a variety of biomaterials used in different approaches of myocardial tissue engineering are reviewed in great detail, and related issues and topics that remain challenges for the future progress of the field are identified at the end of each subsection. This is followed by a brief review on the development of bioreactors (fourth section), which is an important achievement in the field of myocardial tissue engineering, and which is also related to the biomaterials developed. At the end of this article, the major achievements and remaining challenges are summarized, and the most promising paradigm for the future of heart muscle tissue engineering is proposed (fifth section).     

The torsional stiffness of prismatic beams of isosceles triangular cross section: a survey of methods for small included angles

Six approximate methods of calculating the torsional stiffness of prismatic beams of isosceles triangular cross section are compared with the exact solution for the cross section in the form of a sector of a circle.     

Porous Titanium Implants: A Review

Titanium and its alloys are commonly used in almost all disciplines of medicine because of their sufficient biocompatibility and meeting of mechanical requirements. However, dense metallic biomaterials represent only an interfacial connection with host tissue, may develop stress shielding which causes ingrowth of the fibrous tissue, and are prone to microbial adhesion and development of biomaterial associated infections. Therefore, development of a new, porous titanium biomaterial is proposed to improve an implant's interconnection with bone, provide better stabilization, and reduce the risk of the loss of the implant. In this review, recent findings in porous titanium biomaterials engineering are discussed, including the structural and strengthening aspects of titanium alloys. The porosity and design of porous structures, as well as the optimization process are also described. An extensive part of this section is dedicated to manufacturing processes. The next section of the review is devoted to osseointegration of porous implants and surface treatment processes, whose purpose are antibacterial activity or local drug delivery. Summarizing the article, some future predictions have been presented.

     

Estimation of a source term in a quasi steady two-dimensional heat transfer problem: application to an electron beam welding

In previous work, we have analyzed the feasibility of the estimation for a source term S(x, y, z) in a transversal section. The present study is concerned with a two-dimensional inverse phase change problem. The goal is the estimation of the dissipated heat flux in the liquid zone (reconstruction of a source term in the energy equation) from experimentally measured temperatures in the solid zone. This work has an application in the electron beam welding of steels of thickness about 8 cm. The direct thermo-metallurgical problem is treated in a quasi steady two-dimensional longitudinal section (x, y). The beam displacement is normally in the y direction. But in the quasi steady simulation, the beam is steady in the study section. The sample is divided in the axial direction z in few sections. At each section, a source term is defined with a part of the beam and creates a vaporized zone and a fused zone. The goal of this work is the rebuilding of the complete source term with the estimations at each section. In this paper, we analyze the feasibility of the estimation. For this work, we use only the simulated measurements without noise.     

Comparison of the discussion sections of PhD dissertations in educational technology: the case of Turkey and the USA

In academic studies, the discussion section is important in which the effect of the results of the study on the existing literature is highlighted and interpreted. The aim of the current paper is to compare the discussion sections of Turkish and American PhD dissertations in the field of Educational Technologies, taking into consideration the basic features that should be found in an effective discussion section. For this purpose, a content analysis was carried out using a checklist developed to examine the basic components, the presentation of the results, the interpretation of the results, and the overall language of 120 PhD dissertations published in this field. The study showed although there were strong aspects, the contribution to the literature and limitations of studies were only included in some of the Turkish PhD dissertations; however, they were included in the majority of American PhD dissertations. Almost all of the dissertations explained the findings and their significance; however, there was no emphasis on the significant and interesting findings in Turkish PhD dissertations. The number of pages of the discussion section in Turkish and American PhD dissertations was almost the same, and the relationship between the number of pages of the discussion section and the quality of the discussion section was rather weak in the dissertations from both countries. The results obtained from the study were evaluated in general and suggestions to consider when writing the discussion section are given.     

Planning tool requirements for flexible manufacturing: an analytical approach

The problem of tool and fixture resources dimensioning is considered and examined for a productive environment with flexible features. With reference to previous studies, different tool management strategies are pointed out and commented upon; a further control policy based on workpiece batching is suggested and tested. In the second section of the paper, an analytical interpretation of the question in hand is presented and discussed; the effectiveness of the procedure itself is tested by comparing analytical data with results derived from the detailed simulation of a real tool management area. Results are shown in the last section     

Steady state boiling crisis in a helium vertically heated natural circulation loop – Part 1: Critical heat flux,boiling crisis onset and hysteresis

Experiments were conducted on a 2-m high two-phase helium natural circulation loop operating at 4.2 K and 1 atm. The same loop was used in two experiments with different heated section internal diameter (10 and 6 mm). The power applied on the heated section wall was controlled in increasing and decreasing sequences, and temperature along the section, mass flow rate and pressure drop evolutions were recorded. The values of critical heat flux (CHF) were found at different positions of the test section, and the post-CHF regime was studied. The predictions of CHF by existing correlations were good in the downstream portion of the section, however CHF anomalies have been observed near the entrance, in the low quality region. In resonance with this, the re-wetting of the surface has distinct hysteresis behavior in each of the two CHF regions. Furthermore, hydraulics effects of crisis, namely on friction, were studied (Part 2). This research is the starting point to future works addressing transients conducing to boiling crisis in helium natural circulation loops.     

Pulling of glass microcapillaries: Theory and experiment

An approximate analytical solution is obtained which predicts a microcapillary form during pulling which is close to that observed in experiments.Institute of Mechanics and Biomechanics, Bulgarian Academy of Sciences, Sofia. Insitute for Problems of Mechanics, Russian Academy of Sciences, Moscow. Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 63, No. 6, pp. 722–727, December, 1992.Indices 0, p, and 1 denote R, h, and T referring to the initial section (x=0), heating zone boundary (x=l), and fiber section on the receiving device (x=L).     

Analysis of fibre orientation distribution in short fibre reinforced polymers: A comparison between optical and tomographic methods

The fibre orientation distribution in a material sample of short fibre reinforced polyamide extracted from an injection moulded notched plate was analysed using two different methods, one based on micro-computed tomography and the Mean Intercept Length concept and the other based on the classical optical section method. The two methods were compared in terms of the preferred fibre orientation at a chosen position, and the agreement was found to be excellent provided the correct section plane was chosen for the optical method. The optical method was applied to different section planes to ascertain the best choice. Comparisons with the optical method, which can provide the full fibre orientation distribution, confirm that the analysis based on the MIL concept is capable of capturing important information about the fibre orientation.