Calibrating the zoom — a test of Zitt’s hypothesis

Bibliometric indicators are widely used to compare performance between units operating in different fields of science. For cross-field comparisons, article citation rates have to be normalised to baseline values because citation practices vary between fields, in respect of timing and volume. Baseline citation values vary according to the level at which articles are aggregated (journal, sub-field, field). Consequently, the normalised citation performance of each research unit will depend on the level of aggregation, or ‘zoom’, that was used when the baselines were calculated. Here, we calculate the citation performance of UK research units for each of three levels of article-aggregation. We then compare this with the grade awarded to that unit by external peer review. We find that the correlation between average normalised citation impact and peerreviewed grade does indeed vary according to the selected level of zoom. The possibility that the level of ‘zoom’ will affect our assessment of relative impact is an important insight. The fact that more than one view and hence more than one interpretation of performance might exist would need to be taken into account in any evaluation methodology. This is likely to be a serious challenge unless a reference indicator is available and will generally require any evaluation to be carried out at multiple levels for a reflective review.     

Exposing the nonlinear viscoelastic behavior of asphalt-aggregate mixes

In this study asphalt-aggregate mixes are treated as both viscoelastic and viscoplastic. Following a damage mechanics approach, a nonlinear viscoelastic constitutive formulation is generated from a linear formulation by replacing ‘applied stresses’ with ‘effective viscoelastic stresses’. A non-dimensional scalar entity called ‘relative viscoelastic stiffness’ is introduced; it is defined as the ratio of applied to effective viscoelastic stress and encapsulates different types of nonlinearities. The paper proposes a computational scheme for exposing these nonlinearities by uncovering, through direct analysis of any test data, changes experienced by the ‘relative viscoelastic stiffness’. In general terms, the method is based on simultaneous application of creep and relaxation formulations while preserving the interrelationship between the corresponding time functions. The proposed scheme is demonstrated by analyzing a uniaxial tension test and a uniaxial compression test (separately). Results are presented and discussed, unveiling and contrasting the character of viscoelastic nonlinearities in both cases. A conceptual viewpoint is offered to explain the observations, illustrating the requirements from any candidate constitutive theory.     

UK Research Assessment Exercises: Informed judgments on research quality or quantity?

A longitudinal analysis of UK science covering almost 20 years revealed in the years prior to a Research Assessment Exercise (RAE 1992, 1996 and 2001) three distinct bibliometric patterns, that can be interpreted in terms of scientists’ responses to the principal evaluation criteria applied in a RAE. When in the RAE 1992 total publications counts were requested, UK scientists substantially increased their article production. When a shift in evaluation criteria in the RAE 1996 was announced from ‘quantity’ to ‘quality’, UK authors gradually increased their number of papers in journals with a relatively high citation impact. And during 1997–2000, institutions raised their number of active research staff by stimulating their staff members to collaborate more intensively, or at least to co-author more intensively, although their joint paper productivity did not. This finding suggests that, along the way towards the RAE 2001, evaluated units in a sense shifted back from ‘quality’ to ‘quantity’. The analysis also observed a slight upward trend in overall UK citation impact, corroborating conclusions from an earlier study. The implications of the findings for the use of citation analysis in the RAE are briefly discussed.     

‘Triad’ or ‘tetrad’? On global changes in a dynamic world

The US-EU race for world leadership in science and technology has become the favourite subject of recent studies. Studies issued by the European Commission reported the increase of the European share in the world’s scientific production and announced world leadership of the EU in scientific output at the end of the last century. In order to be able to monitor those types of global changes, the present study is based on the 15-year period 1991–2005. A set of bibliometric and technometric indicators is used to analyse activity and impact patterns in science and technology output. This set comprises publication output indicators such as (1) the share in the world total, (2) subject-based publication profiles, (3) citation-based indicators like journal-and subject-normalised mean citation rates, (4) international co-publications and their impact as well as (5) patent indicators and publication-patent citation links (both directions). The evolution of national bibliometric profiles, ‘scientific weight’ and science-technology linkage patterns are discussed as well. The authors show, using the mirror of science and technology indicators, that the triad model does no longer hold in the 21^st century. China is challenging the leading sciento-economic powers and the time is approaching when this country will represent the world’s second largest potential in science and technology. China and other emerging scientific nations like South Korea, Taiwan, Brazil and Turkey are already changing the balance of power as measured by scientific production, as they are at least in part responsible for the relative decline of the former triad.     

Allowance for mutual effect of ‘Hot spots’ in solution of problems of site thermal explosion

Local effect of intensification of substance heating depending on the distance between ‘hot spots’ is studied within the framework of a site thermal explosion in the case of a zeroth-order reaction. A combination of the values of the Arrhenius number Ar, Frank-Kamenetskii criterion Fk, distance between ‘hot spots’ a, and their width w at which two nearest points give a nonlinear effect of local intensification of the total heating of a substance is found. The method is based on the use of an approximate analytical solution of the corresponding Cauchy problem which is presented in the form of asymptotic expansion in terms of Poincare. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 73, No. 1, pp. 189–192, January–February, 2000.     

Africa’s contribution to the worldwide research literature: New analytical perspectives,trends, and performance indicators

This paper examines general characteristics of African science from a quantitative ‘scientometric’ perspective. More specifically, that of research outputs of Africa-based authors published in the scientific literature during the years 1980–2004, either within the international journals representing ‘mainstream’ science, or within national and regional journals reflecting ‘indigenous science’. As for the international journals, the findings derived from Thomson Scientific’s Citation Indexes show that while Africa’s share in worldwide science has steadily declined, the share of international co-publications has increased very significantly, whereas low levels of international citation impact persist. A case study of South African journals reveals the existence of several journals that are not processed for these international databases but nonetheless show a distinctive citation impact on international research communities.     

Crack growth in structural adhesive joints in aqueous environments

The adhesive fracture energy, G _c , of metallic joints, bonded with a rubber-toughened epoxy adhesive, has been measured using monotonically-loaded tests. Such tests have been conducted in various relative humidities and in water, at 21 °C. Two surface pretreatments have been employed for the substrates prior to bonding: a simple grit-blast and degrease (‘GBD’) pretreatment or a grit-blast, degrease and silane primer (‘GBS’) pretreatment. The joints were formed using metallic substrates which were either (a) aluminium-alloy substrates, (b) steel substrates, or (c) ‘dissimilar’ substrates (i.e. one substrate being aluminium-alloy with the other one being steel). For both test environments, when G _c was plotted against the crack velocity, three regions of fracture behaviour could be distinguished. At low rates of displacement the crack grew in a stable manner, visually along the interface, and relatively low crack velocities could be readily measured. This was termed ‘Region I’ and here the value of G _c measured in the aqueous environment was relatively low compared to that measured in a relatively dry environment of 55% relative humidity. On the other hand, at relatively high rates of displacement the crack always grew in a stick-slip manner mainly cohesively in the adhesive layer at approximately 20 km/min. This was termed ‘Region III’, and here the value of G _c was relatively high and independent of the environmental test conditions employed. In this region the crack was considered to grow faster than the water molecules were able to reach the crack tip, which explains the independence of G _c upon the test environment. In between ‘Region I’ and ‘Region III’, a transition region was observed which was designated as ‘Region II’. The major effect of the ‘GBS’ pretreatment, compared to the ‘GBD’ pretreatment, was to increase the value of G _c both in ‘Regions I and III’, although the presence of the silane primer had the far greater effect in ‘Region I’.     

The global science base of information and communication technologiges: Bibliometric analysis of ICT research papers

The science and engineering base is a key source of knowledge for the development and use of Information and Communication Technologies (ICTs). In order to be able to effectively describe and monitor world-wide scientific activity related to ICTs, it is important to be able to provide reliable macro-level statistics of this knowledge base. International bibliographic databases and related bibliometric indicators together provide an analytical framework and appropriate measures to cover both the ‘supply side’—research capabilities and outputs—and ‘demand side’—collaboration, diffusion and citation impact—related to the ICT research. This paper presents results of such a bibliometric study describing macro-level features of this ICT knowledge base. The data were retrieved from a specially developedCWTS ICT Database which provides a broad-scope world-wide coverage of ICT-relevant research papers published in high-quality international scientific and technical journals. The cross-country comparison focuses on the level of scientific output and co-operation patterns of the most actively publishing nations with a focus on the three Triad zones—the European Union, the USA and Japan.     

Shapley values for assessing research production and impact of schools and scholars

Performance measures of individual scholars tend to ignore the context. I introduce contextualised metrics: cardinal and ordinal pseudo-Shapley values that measure a scholar’s contribution to (perhaps power over) her own school and her market value to other schools should she change job. I illustrate the proposed measures with business scholars and business schools in Ireland. Although conceptually superior, the power indicators imply a ranking of scholars within a school that is identical to the corresponding conventional performance measures. The market value indicators imply an identical ranking within schools and a very similar ranking between schools. The ordinal indices further contextualise performance measures and thus deviate further from the corresponding conventional indicators. As the ordinal measures are discontinuous by construction, a natural classification of scholars emerges. Averaged over schools, the market values offer little extra information over the corresponding production and impact measures. The ordinal power measure indicates the robustness or fragility of an institution’s place in the rank order. It is only weakly correlated with the concentration of publications and citations.     

Delineating the scientific footprint in technology: Identifying scientific publications within non-patent references

Indicators based on non-patent references (NPRs) are increasingly being used for measuring and assessing science–technology interactions. But NPRs in patent documents contain noise, as not all of them can be considered ‘scientific’. In this article, we introduce the results of a machine-learning algorithm that allows identifying scientific references in an automated manner. Using the obtained results, we analyze indicators based on NPRs, with a focus on the difference between NPR- and scientific non-patent references-based indicators. Differences between both indicators are significant and dependent on the considered patent system, the applicant country and the technological domain. These results signal the relevancy of delineating scientific references when using NPRs to assess the occurrence and impact of science–technology interactions.     

Correcting glasses help fair comparisons in international science landscape: Country indicators as a function of ISI database delineation

The increasing use of bibliometric indicators in science policy calls for a reassessment of their robustness and limits. The perimeter of journal inclusion within ISI databases will determine variations in the classic bibliometric indicators used for international comparison, such as world shares of publications or relative impacts. We show in this article that when this perimeter is adjusted using a natural criterion for inclusion of journals, the journal impact, the variation of the most common country indicators (publication and citation shares; relative impacts) with the perimeter chosen depends on two phenomena. The first one is a bibliometric regularity rooted in the main features of competition in the open space of science, that can be modeled by bibliometric laws, the parameters of which are “coverage-independent” indicators. But this regularity is obscured for many countries by a second phenomenon, the presence of a sub-population of journals that does not reflect the same international openness, the nationally-oriented journals. As a result indicators based on standard SCI or SCISearch perimeters are jeopardized to a certain extent by this sub-population which creates large irregularities. These irregularities often lead to an over-estimation of share and an under-estimation of the impact, for countries with national editorial tradition, while the impact of a few mainstream countries arguably benefits from the presence of this sub-population. This revised version was published online in August 2006 with corrections to the Cover Date.     

The equivalent pore pressure and the swelling and shrinkage of cement-based materials

We revisit the approach to the drying shrinkage of cement-based materials using Poromechanics of unsaturated materials. It is in particular shown that the equivalent pore pressure concept, by opposition to the averaged pore pressure, can account for the surface energy effect upon the drying shrinkage. Experimental evidence shows that the influence of the latter reveals to be essential for intermediary values of the relative humidity since the contribution of the interfacial energy significantly increases as the relative humidity is reduced.

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Résumé Nous appliquons ici les outils de la Poromécanique des milieux non saturés à l'étude du retrait de séchage des matériaux à base ciment. Nous montrons en particulier que le concept de pression de pore équivalente par opposition à celui de pression de pore moyenne peut rendre compte des effets de l'énergie de surface sur le retrait de séchage. L'expérience montre que la prise en compte de cette énergie de surface s'avère être essentielle dans la compréhension du retrait pour les saturations intermédiaires. La contribution de cette énergie devient en effet de plus en plus prépondérante au fur et à mesure que l'humidité relative est abaissée.

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Editorial Note Dr. Véronique Baroghel-Bouny is a RILEM Senior Member. She participates in RILEM TCs 178-TMC ‘Testing and Modelling chloride penetration in Concrete’, 195-DTD ‘Recommendation for test methods for autogenous deformation and thermal dilation of early age concrete’ and 196-ICC ‘Internal curing of concretes’ and works at LCPC, a RILEM Titular Member. Dr. Coussy and Dr. Baroghel-Bouny are members of the Editorial Advisory Committee ofConcrete Science and Engineering.     

Mapping inventive activity and technological change through patent analysis: A case study of India and China

The characteristics of Indian and Chinese patenting activity in the US patent system are examined by delineating two categories of patents; ‘nationally assigned’, and ‘invented not nationally assigned’ patents (not-nationally assigned patents in short). Further within the above two categories, patents are distinguished and analysed in terms of patent types: utility, design, and plant patents. Indian patents are mainly of utility type whereas China's activity falls in both utility and design.In the ‘nationally assigned’ patents, the different types of institutions involved and linkages are much higher for China. However, ‘not-nationally assigned’ patents of both the countries are dominated by industry and inter-institutional collaborations are sparse. Patents addressing technology sectors (analysis based on utility patents) do not exhibit major differences between the two categories in Chinese patents and address with varying degree all technology sectors. Unlike China, India's ‘nationally assigned’ patents are concentrated in chemical and drugs & medical whereas their ‘not-nationally assigned’ patents are similar to that of China in addressing technology sectors. In design patents, Chinese ‘nationally assigned’ patents mainly cover ornamental design of lighting equipments whereas their ‘not-nationally assigned’ patents are mainly in design equipment for production, distribution or transformation of energy. Further, few firms are active in design patents in both the categories. India's design activity is insignificant in both the categories. The paper concludes by examining the results in the policy context. This revised version was published online in June 2006 with corrections to the Cover Date.     

Profiling institutes: Identifying high research performance and social relevance in the social and behavioral sciences

This study focuses on the identification of high output research and high impact research in the social and behavioral sciences. A second objective is to monitor developments in research that is related to societal needs and problems. For each topic, we identify institutes and authors that have contributed a considerable number of SSCI articles and/or several (relatively) highly cited articles on a topic. To identify papers with a (relatively) high impact, the present study used two citation thresholds, each based upon a combination of a statistically determined minimum number of ‘external’ citations (by others than the authors of a paper), and a statistical comparison with world average citation levels. Topics were categorised according to social relevance. Detailed profiles of both large and small institutes are obtained, showing strengths and weaknesses in research performance that tend to be obscured by standard indicators focusing on ‘average’ research performance. Socially relevant topics tend to be concentrated in multidisciplinary clusters, whereas clusters dominated by one or two disciplines contain more basis research. The results provide a first insight in the extent to which institutes and authors address socially relevant topics. Use of the results by policy bodies seems dependent upon which organisational level of research they tend to address.     

Energy characteristics of mass transfer in porous solids

We obtained equations for the energy characteristics of the system ‘solid-liquid (vapor)’ and its individual phases and for numerical values of the energy characteristics for various systems, including ones used in industry. Their analysis is performed and an assessment from the energy standpoint is given. The ‘mesobody’ concept is introduced and described qualitatively. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 73, No. 2, pp. 283–287, March–April, 2000.     

Optimising an expansion test for the assessment of alkali-silica reaction in concrete structures

This work is part of an overall project for the reassessment of concrete structures damaged by alkali-silica reaction (ASR). The paper focuses on developing a laboratory method for expansion tests since the usual tests appear to be difficult to use in expert assessment. The development involves optimising the storage conditions and the sizes of the specimen and aggregate. A combined effect of the aggregate and specimen sizes on ASR expansion is thus pointed out: for a given mortar, the expansion is lower in small specimens than in large specimens. Therefore, the ratio ‘specimen size/aggregate size’ has to be sufficiently high to decrease this scale effect and obtain relevant measurements. The discussion proposes a method for always using comparable conditions during the expansion tests and finally suggests how this test can be optimised to provide fast and relevant results for use in structure reassessment.     

Simulations of opinion changes in scientific communities

We present a computer model of opinion changes in a scientific community. The study takes into account two mechanisms of opinion formation for individual scientists: influence of coworkers with whom there is direct interaction and cumulative influence of the subject literature. We analyze the evolution of relative popularity of different competing theories, depending on their accuracy in describing observed phenomena and on current social support of the theory. We include such aspects as finite lifetime of publication impact and tendency to ‘defend’ one’s own opinions, especially if they were already published. A special class of publications, delivering crucial observational or experimental data, which may revolutionize the scientific worldview is considered. The goal of the model is to discover which conditions lead to quick domination of one theory over others, or, conversely, in which situations one may expect several explanations to co-exist.     

Influence of crystallographic textures on tensile properties of 316L austenitic stainless steel

Role of cold rolling texture on the tensile properties of the cold rolled and cold rolled and annealed AISI 316L austenitic stainless steel is described here. The solution-annealed stainless steel plates were unidirectionally cold rolled to 50, 70 and 90% of reduction in thickness. The cold rolled material was annealed at 500–900 °C annealing temperatures. X-ray diffraction technique was employed to study the texture evolution in cold rolled as well as cold rolled and annealed conditions. The texture components that evolved were translated into slip transmission number ‘λ’ and Schmid factor ‘μ’. These two parameters were correlated with the tensile properties of the material. The tensile properties were evaluated under all processing conditions. Softening of the cold rolled material was observed after annealing with increasing annealing temperatures. From the stress–strain curves, strain hardening coefficient ‘n’ and strain hardening rate ‘θ’ were determined. It was found that the effect of texture on tensile behaviour could be understood clearly by strain hardening rate. Out of the two parameters, ‘n’ and ‘θ’, strain hardening rate was found to be more sensitive to type of texture in the material.     

A study of phase separation in ternary alloys

We have studied the evolution of microstructure when a disordered ternary alloy is quenched into a ternary miscibility gap. We have used computer simulations based on multicomponent Cahn-Hilliard (CH) equations for c _A and c_B, the compositions (in mole fraction) of A and B, respectively. In this work, we present our results on the effect of relative interfacial energies on the temporal evolution of morphologies during spinodal phase separation of an alloy with average composition, c_A = 1/4, c_B = 1/4 and c_c = 1/2. Interfacial energies between the ‘A’ rich, ‘B’ rich and ‘C’ rich phases are varied by changing the gradient energy coefficients. The phases associated with a higher interfacial energy are found to be more rounded than those with lower energy. Further, the kinetic paths (i.e. the history of A-rich, B-rich and C-rich regions in the microstructure) are also affected significantly by the relative interfacial energies of the three phases.