Inspecting the Achilles heel: a quantitative analysis of 50 years of family business definitions

Despite numerous attempts by academics from many disciplines and various regional contexts, there is still no agreement on a definition of family business. Subjecting 258 definitions found in work published over the past 50 years (1964–2013) to the bibliometric techniques of consensus and co-word analysis to uncover intellectual structure, we identify the key terms used to underpin the concept of family business and to track the progress made towards consensus on its definition. We find an emergence of definitional key terms by which scholars attempt to clarify the concepts of family and family business, and growing agreement of what criteria should be met in framing a definition. This study contributes to the literature by offering a synthesis of what constitutes a family business, as well as a systematic and quantitative analysis of its evolution over a half century of research. It also shows how bibliometric tools can be used to shed light on fields where definitional ambiguity persists.     

Behavior of a single nitrogen molecule on the pentagon at a carbon nanotube tip: a first-principles study

Density functional theory (DFT) is used to investigate the adsorption properties of nitrogen on the pentagon at the tip of a capped (5, 5) single-walled carbon nanotube. The adsorption of N(2) outside the carbon nanotube with a parallel orientation with respect to the plane of the pentagon is found to be the most stable state of adsorption. Its binding energy of -0.318?eV is very small, with a large C-N equilibrium distance of 2.94??. We have also investigated the number and the position of adsorption sites in the pentagon for the parallel configuration. This knowledge can lead to the precise control of adsorption states, and consequently may bring about a novel multistate monomolecular device. We find two stable configurations of the molecule that have only a small difference in energy, while the other configurations are energetically unfavorable. Our results support previous experimental predictions that the nitrogen molecule transits between two states with a small current pulse. The predicted position sites for the transient states are in reasonable agreement with experimental observations.     

In vitro study on the influence of strontium-doped calcium polyphosphate on the angiogenesis-related behaviors of HUVECs

Angiogenesis is of great importance in bone tissue engineering, and has gained large attention in the past decade. Strontium-doped calcium polyphosphate (SCPP) is a novel biodegradable material which has been proved to be able to promote in vivo angiogenesis during bone regeneration. An in vitro culture system was developed in the present work to examine its influence on angiogenesis-related behaviors of human umbilical vein endothelial cells (HUVECs), including cell adhesion, spreading, proliferation and migration. The effects of microtopography, chemical property and the ingredients in the degradation fluid (DF) on cell behaviors were discussed. The results showed that cells attached and spread better on SCPP scaffold than on calcium polyphosphate (CPP), which might partially result from the less rough surface of SCPP scaffold and the less hydrogel formed on the surface. In addition, cell proliferation was significantly improved when treated with SCPP DF compared with the treatment with CPP DF. Statistical analysis indicated that Sr(2+) in SCPP DF might be the main reason for the improved cell proliferation. Moreover, cell migration, another important step during angiogenesis, was evidently stimulated by SCPP DF. The improved in vivo angiogenesis by SCPP might be assigned to its better surface properties and strontium in the DF. This work also provides a new method for in vitro evaluation of biodegradable materials' potential effects on angiogenesis.     

Annealing behaviour of a nanostructured Cu–45 at.%Ni alloy

The microstructure and crystallographic texture have been investigated in a Cu–45 at.%Ni alloy after heavy rolling and subsequent annealing at different temperatures. Cold-rolling to a von Mises strain of 5.7 produced a sample with an average boundary spacing along the normal direction of ~70 nm and a large fraction of high-angle boundaries (HABs), ~70 %. Annealing of this sample for 1 h at temperatures ≤450 °C causes structural coarsening, during which the fraction of HABs decreases. Annealing at higher temperatures results in pronounced discontinuous recrystallization accompanied by twinning. Large frequencies of twin boundaries contribute to high HAB fractions measured in the as-recrystallized condition. Cube-oriented grains demonstrate a size advantage compared to grains of other orientations, thus creating a strong cube texture in the recrystallized material. Further annealing of the recrystallized microstructure promotes grain growth, which leads to a significant strengthening of the cube texture and to a dramatic loss of HABs. After 1 h of annealing at 1000 °C the fraction of the cube texture reaches 99 % and the HAB fraction is 12 %.     

Phenomenology of the creep process of a precipitation-hardenable AlMgSi alloy wires for overhead power lines. Experimental tests. Simulation

The article presents the results of the experimental test on the creep process of AlMgSi alloy wires (series 6xxx) under the conditions of variable stress. A theoretical analysis of equivalency rheological results of stress and temperature changes by means of Bayley-Norton function, which describes well the low-temperature aluminum alloys creep, was carried out. Therefore, the described issue became one-dimensional. On the basis of experimental tests, it has been proved that negative gradients of stress and temperature may generate three types of rheological behaviour, such as: Temporary decrease of creep speed (type 1), Temporary stop of creep deformation (‘dead’ time)—type 2 and reverse after creep (type 3). The applicable nature of tests is placed in overhead power lines, which undergo cyclical stress- and time-dependent operation. Such a nature of conductor operation creates favourable conditions to decrease creep intensity, whereas its history and value and speed of stress and temperature lowering decide whether conductor rheological activity loss will take place. The actual material parameter controlling the conductor rheological behaviour is stress and temperature rheological equivalent. The article contains exemplary results of current-carrying capacity changes of AlMgSi alloy conductor on a given temperature range, and the calculations include actual creep characteristic and cumulated rheological inactivity caused by negative gradients of stress and temperature.     

The effect of residual stresses in the ZnO buffer layer on the density of a ZnO nanowire array

Density control is a valuable concern in the research of ZnO nanowire arrays. In this study, unannealed and annealed ZnO thin films were used as substrates to fabricate ZnO nanowire arrays. In the unannealed thin film, an inhomogeneous distribution of the nanowire array was found: the density of nanowires decreases with the increase of distance to the edge. In the annealed thin film, the density of nanowire array becomes larger and more homogeneous. Moreover, nanowires are found in high density along microcracks. It is proposed that the residual stresses in the thin film and the density of the nanowire array are in inverse proportion, leading to the results mentioned above. The relationship between residual stresses and the density of nanowires will have potential applications in modifying the density of ZnO nanowire arrays.     

Comments on “a study on the interconnection of slotted random access networks”

Abstract

The results obtained in many experimental data show that the effect of turbulent diffusion on the performance of an electrostatic precipitator (ESP) is significant. The ways of handling the turbulent diffusion effect in different efficiency models are different. The effects of turbulent diffusion modeling on ESP performance models are investigated by comparing various models which include plug, Deutsch, Cooperman, Leonard‐Mitchner‐Self (L‐M‐S), and 2nd‐order closure models. The results obtained show that the largest difference of the estimation values of collection efficiency between various models in the range 0–10000 cm²/s of diffusivity is about 28%. When the diffusivity is less than 300 cm²/s, the x‐direction diffusion effect makes no obvious contribution to collecting process but the y‐direction diffusion effect makes a marked contribution. When the diffusivity is larger than 300 cm²/s, the uncollected particles are mixed well in the y‐direction and the influence of x‐direction diffusion effect on collection efficiency becomes sensitive with the increase in diffusivity. Moreover, it is shown that the collection efficiency decreases when the entrance concentration increases. When the flow velocity is small, the migration velocity increases with increasing flow velocity. This anomalous phenomenon can be explained by the ionic wind effect, and the case studies show that there exists a maximum collection efficiency when the flow velocity is about a half of the ionic wind velocity.     

Time series analysis of publication counts of a university: what are the implications?

Yearly publication counts of research institutions and universities continue to be a widely-used parameter to assess their research productivity, and such evaluations have been successfully used to analyze the influence of research support policies at various levels. This study was designed to analyze the yearly number of articles having an Akdeniz University address and that appeared in the Web of Science databases from 1996 to 2009. Time series analysis of the number of published articles was used to determine the impact of alterations in the number of faculty members and research funding as well as changes in the institutional and country-wide research support policies and encouragement mechanisms. It was observed that alterations in both the number of faculty members who are active in research and the total amount of research funding each year may explain the general pattern published articles. However, there is a period with significant deviations from the trend predicted by these relationships. This period, corresponding to the years 2002–2008, is discussed in terms of the effects of policy changes which may have positive and negative contributions to the predicted pattern. Mathematical analysis of publication time series, together with parameters expected to affect research output, may provide valuable insight into the effectiveness of research support mechanisms.     

TiO2–Cu photocatalysts: a study on the long- and short-range chemical environment of the dopant

In this study, the short- and long-range chemical environments of Cu dopant in TiO₂ photocatalyst have been investigated. The Cu-doped and undoped TiO₂ specimens were prepared by the sol–gel approach employing CuSO₄·5H₂O and Ti(O-iPr)₄ precursors and subjecting the dried gels to thermal treatment at 400 and 500 °C. The photocatalytic activity, investigated by methylene blue degradation under sunlight irradiation, showed a significantly higher efficiency of Cu-doped samples than that of pure TiO₂. The X-ray diffraction results showed the presence of anatase phase for samples prepared at 400 and 500 °C. No crystalline CuSO₄ phase was detected below 500 °C. It was also found that doping decreases the crystallite size in the (004) and (101) directions. Infrared spectroscopy results indicated that the chemical environment of sulfate changes as a function of thermal treatment, and UV–vis spectra showed that the band gap decreases with thermal treatment and Cu doping, showing the lowest value for the 400 °C sample. X-ray absorption fine structure measurements and analysis refinements revealed that even after thermal treatment and photocatalytic assays, the Cu²⁺ local order is similar to that of CuSO₄, containing, however, oxygen vacancies. X-ray photoelectron spectroscopy data, limited to the near surface region of the catalyst, evidenced, besides CuSO₄, the presence of Cu¹⁺ and CuO phases, indicating the active role of Cu in the TiO₂ lattice.     

A long-term evaluation of osteoinductive HA/β-TCP ceramics in vivo: 4.5 years study in pigs

It has been proved that some material-dependent calcium phosphate ceramics have intrinsic potentials to induce osteogenesis. But there is little literature concerning about the tissue response in long-term. The aim of this study is to evaluate the safety of the osteoinductive biocreamics and the stability of the newly formed bone after long-term tissue response. Porous calcium phosphate ceramics rods which contain hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) were implanted in the dorsal muscles of Banna Minipig Inbreding Line. After 4.5 years, all the implanted rods with surrounding tissues were harvested and stained with hematoxylin and eosin for histological observation. The 7 months’ rods were also harvested as short-term comparison. The histological results showed that compared with the short-term rods, amount of bone tissue formed after 4.5 years. And the newly formed bone in this bioceramics neither disappeared nor gave rise to uncontrolled growth. The bone growth in this bioceramics seemed to be self-confined. The surrounding soft tissues were normal and no tumor cell was found. We conclude that instead of disappearing or giving rise to out of control, the induced bone tissue trends to be further matured. And this bioceramics thus might have potentials in future clinical use.     

Equal-Channel Multi-Angle Pressing Effect on the Properties of NbTi Alloy

An improvement of NbTi alloy functional properties by equal-channel multi-angle pressing (ECMAP) combined with hydrostatic extrusion, drawing and thermal treatment is revealed. The ECMAP method allows to increase the billet accumulated deformation with preserving its initial dimensions. The formed highly dispersed and homogeneous nanocrystalline structure with a more uniform distribution of α-phase precipitations as a result of ECMAP treatment improves the functional properties of the alloy. In the field of 5 T, the critical current density in wire samples produced with application of the ECMAP method is enhanced approximately by a factor of 2 in comparison with the values obtained for the samples produced without the ECMAP treatment.     

Experimental study on the separation performance of a novel gas–liquid separator

A novel two-stage dynamic separator called high-gravity cyclone separator (HGCS) has been designed for gas–liquid separation. It is mainly composed of a cyclone chamber and rotary drum. In this study, its performance, including the separation efficiency and pressure drop, is experimentally investigated, and the effects of the operating conditions and drum parameters are evaluated. For droplets with a mean diameter of 7 μm, the results indicate that the optimal gas inlet velocity and high-gravity factor are 12 m/s and 59.4, respectively, and the separation efficiency reaches 98 %. The effect of liquid concentration is sensitive to the high-gravity factor. At a liquid concentration of 57 g/m³, the maximum efficiency will be 98.75 % when increasing the high-gravity factor to 85.6. Furthermore, a smaller radial height is preferable when the gas inlet velocity is greater than 12 m/s, and a better separation efficiency can be obtained by increasing the drum length to 190 mm. However, when the length is 235 mm, the efficiency will be poor because of the Kelvin–Helmholtz and Rayleigh–Taylor instabilities. Compared with the predominant roles of gas inlet velocity, drum length and radial height in pressure drop, the effects of liquid concentration and high-gravity factor are small.     

Two features of the uniaxial compression of a glassy epoxy resin: the yield stress rate-dependence and the volumetric instability

We report the results of uniaxial compressive tests on a DGEBA epoxy resin at room temperature, well below its glass transition. We first focus on the strength, defined as the stress value corresponding to either a maximum or a flattening of the stress-strain curve, which, for this polymer, may be taken to be coincident with the yield stress, as often assumed for many thermosets. Within the strain rate range (1.E?6 s^?1, 2.E?3 s^?1) we confirm the linear trend relating the logarithm of the strain rate to the yield stress, as already been observed by other investigators even for the same epoxy resin; instead, at strain rates below \(\dot{\varepsilon} _{0} \approx 1.\mathrm{E}{-}6~\mathrm{s}^{-1}\), we found a negligible rate-dependence, as our data indicate a lowest limit of the yield stress, of about 87 MPa. On the basis of these results, we propose how to extend to the viscoplastic regime of deformation a nonlinear viscoelastic model previously put forward.Secondarily, within the viscoelastic range, at a stress level significantly lower than the yield stress, our measurements show a mild volumetric instability, allowed by the free lateral expansion, not ascribable to any macroscopic structural effect; such a behaviour has never been reported in the literature, to the best of our knowledge.     

Characterization of the Response of CaWO4 on Recoiling Nuclei from Surface Alpha Decays

A potentially harmful background for experiments attempting direct dark matter detection like the CRESST (= Cryogenic Rare Event Search with Superconducting Thermometers) experiment is caused by recoiling nuclei from ²¹⁰Po alpha decays on surfaces close to the detector. In order to characterize this kind of background in CRESST, calibration measurements have been performed at the TU München. A for this purpose an optimized version of the CRESST detector has been developed consisting of a 38 g CaWO₄ crystal and a separate cryogenic light detector, both equipped with Ir/Au transition edge sensors (TESs). The simultaneous measurement of the phonon signal and the scintillation light from the CaWO₄ crystal allows to discriminate between electron and nuclear recoils using their different light outputs. The unexpected results of a first measurement with a ²¹⁰Po source can be understood with the help of a Monte Carlo simulation performed for a similar system.      

Determination of the Photon Impact Position within a DROID

Distributed read-out imaging detectors (DROIDs) combine a good energy resolution with a high position resolving power. Therefore they are promising candidates to build cameras with a huge detection area. A new method is proposed to determine the photon energy and impact position from the two signals of a one-dimensional DROID. For this purpose the diffusion equation was solved for asymmetric devices with arbitrarily trapping. The new method is then applied to fit the experimental data obtained from the illumination with soft X-ray of a 400 μm long Ta absorber strip with one Ta/Al read-out STJ at each end.      

Global research output on date palm (Pheonix dactylifera): a 12 years scientometric perspective

Date palm (Phoenix dactylifera) is one of the commonly used polyphenolic rich fruits attributing also to various therapeutic effect in different diseases and disorders. We aimed to study and analyse the global research output related to date palm based on a fact of its large consumption and production in Middle East. We analysed 1,376 papers obtained from SCOPUS database for the period of 2000–11. The study examines major productive countries and their citation impact. We have also analysed inter-collaborative linkages, national priorities of date palm research, besides analysing the characteristics of its high productivity institutions, authors and journal.