Origin and emergence of entrepreneurship as a research field

This paper seeks to map out the emergence and evolution of entrepreneurship as an independent field in the social science literature from the early 1990s to 2009. Our analysis indicates that entrepreneurship has grown steadily during the 1990s but has truly emerged as a legitimate academic discipline in the latter part of the 2000s. The field has been dominated by researchers from Anglo-Saxon countries over the past 20 years, with particularly strong representations from the US, UK, and Canada. The results from our structural analysis, which is based on a core document approach, point to five large knowledge clusters and further 16 sub-clusters. We characterize the clusters from their cognitive structure and assess the strength of the relationships between these clusters. In addition, a list of most cited articles is presented and discussed.     

Temperature-dependent refractive index of potassium acid phthalate (KAP) in the visible and near-infrared

We report an investigation of the temperature-dependence of the refractive index of potassium acid phthalate (KAP) crystal. Refractive index measurements are based on a refractometer setup operating in a temperature range from 25 °C to 200 °C and using five different laser wavelengths in the visible and near-infrared. Temperature-dependent dispersion relations are proposed, with an average fitting quality that exceeds experimental accuracy, and compared to previous room-temperature Sellmeier equations. Consequently, the new relations are employed for the calculation of various linear and nonlinear optical properties of KAP.     

Anomalous absorption of isolated silver nanoparticulate films in visible region of electromagnetic field

Anomalous absorption of isolated silver nanoparticulate films with different morphological patterns prepared by the wet colloidal route and followed by thermal treatment were investigated. A polymer embedded silver nanoparticulate film thermally treated at 200 degrees C showed maximum absorbance at approximately 412 nm. The peak position of the surface plasmon band was slightly different but still consistent with theoretical prediction derived by the Mie theory. An isolated nanopariculate film thermally treated at 300 degrees C showed anomalous absorption. Its maximum absorption band was shifted to green regime of 506.9 nm and the bandwidth at half-maximum absorbance of the surface plasmon band was greatly broadened. The plasmon band and its bandwidth were much deviated compared to the theoretical prediction calculated for the silver nanoparticles in the surrounding medium of air and poly(vinyl pyrrolidone) or soda-lime-silica glass. Even though there was no significant growth of silver nanoparticles during thermal treatment at 300 degrees C, the anomalous absorption was observed. The anomalous absorption was not attributed to effects of particle shape and size but to effects of pores induced by development of a great number of pores in the nanoparticulate film. The anomalous absorption greatly decreased with increase in heating temperature from 400 degrees C to 500 degrees C. The extraordinary plasmon damping of the isolated film decreased and the plasmon absorption band was re-shifted to violet regime of 416 nm because of large decrease in size of particles with dramatic change of pore morphology from circular pores with rim to small continuous pores induced by spontaneous formation of new silver nanoparticles.     

UV and visible optical absorbance in CuCl nanoclusters in an external electric field

The optical absorbance in UV and visible wavelength in CuCl nanoclusters in an external electric field is determined at room temperature. The wavelength dependence of the absorbance change is nonlinear at a fixed applied field. At a fixed wavelength, the absorbance changes as an increasing applied field varies quadratically.     

Ultrasensitive, visible tunable diode laser detection of NO(2)

Recent advances in room-temperature visible diode lasers and ultrasensitive detection techniques have been exploited to create a highly sensitive tunable diode laser absorption technique for in situ monitoring of NO(2) in the lower troposphere. High sensitivity to NO(2) is achieved by probing the visible absorption band of NO(2) with an AlGalnP diode laser at 640 or 670 nm combined with a balanced ratiometric electronic detection technique. We have demonstrated a sensitivity of 3.5 × 10(10) cm(-3) for neat NO(2) in a 1-m path at 640 nm and have estimated a sensitivity for ambient operation of 5 ppbv m (l0 ppbv m at 670 nm), where ppbvm is parts in 10(9) by volume per meter of absorption path length, from measured pressure-broadening coefficients.     

Exploring entrepreneurship in the academic environment

The entrepreneurial university has taken a prodigious influence globally, and studies show the expedient value of entrepreneurship in universities performing innumerable activities alongside their main objectives of teaching and research. Universities worldwide are adopting entrepreneurship teaching through creating models and methods. Collaboration of research, industry, and government entities is crucial to fulfill innovative systems in the academic environment. This study evaluates academic faculty and their impact on entrepreneurial education by focusing on their work experience, position, involvement in technical projects, international work experience, and private sector experience. Analysis of Variances (ANOVA), Least Significant Difference (LSD) assessments are conducted to support the results of our hypotheses and the variables of the entrepreneurial education impact by understanding the interpersonal aspects of faculty within academic organizations.     

Kinetics of the decoloration of reactive dyes over visible light-irradiated TiO(2) semiconductor photocatalyst

Photocatalytic decoloration kinetics of triazine (Reactive Red 11, Reactive Red 2, and Reactive Orange 84) and vinylsulfone type (Reactive Orange 16 and Reactive Black 5) of reactive dyes have been studied spectrophotometrically by following the decrease in dye concentration with time. At ambient conditions, over 90-95% decoloration of above dyes have been observed upon prolonged illumination (15 h) of the reacting system with a 150 W xenon lamp. It was found that the decoloration reaction followed first-order kinetics. The values of observed rate constants were found to be dependent of the structure of dyes at low dye concentration, but independent at higher concentration. It also reports for the first time the decoloration of two different dyes together in a binary dye mixture using visible light-irradiated TiO(2) photocatalyst. Rate of decoloration of two different dyes together in a binary dye mixture using visible light-irradiated TiO(2) photocatalyst is governed by the adsorptivity of the particular dye onto the surface of the TiO(2) photocatalyst.     

A Comparison of Transverse Cracking Phenomena in (0/90)s and (90/0)s CFRP Laminates

The development of 90° ply cracking in the surface plies of (90/0)_s CFRP laminates from two material systems, HTA/F922 and HTA/F927, has been studied experimentally and the results compared with previous work on (0/90)_s lay-ups from the same systems. The trends of the results are shown to be consistent with other published literature. The role of defects in crack initiation and the implications for using a fracture mechanics approach to model the observed behaviour are discussed.     

Hidden isosbestic point(s) in ultraviolet spectra

The existence of isosbestic point(s) in a set of UV-visible spectra is rarely exploited for quantitative or qualitative information despite its interest. Indeed, the presence of isosbestic points means a quality and quantity conservation in the global composition of samples with a given relation between the concentration of absorbing compounds or mixtures of compounds. However, in some cases, for example, when a dilution occurs, no isosbestic point appears. This work shows that a simple operation, called normalization, can reveal the existence of hidden isosbestic point(s) (IP*). This paper first summarizes the required conditions for the presence of isosbestic points. Second, it demonstrates the significance of IP* revealed by normalization. An example of the exploitation of direct or hidden isosbestic points in the environmental field illustrates the interest in and application of the technique.     

Constraint comparisons for common fracture specimens: C(T)s and SE(B)s

New testing standards (e.g., ASTM E1921) remain under continuing development to measure the fracture toughness of ferritic steels over the ductile-to-brittle transition. The procedures assume that relatively small, deep-notch test specimens maintain near small-scale yielding conditions at fracture, which simplifies greatly the interpretation of measured values. However, 3-D finite element analyses suggest that the geometry and small size of common fracture specimens leads frequently to constraint loss, e.g., the decay of small-scale yielding conditions, at only moderate levels of deformation. The Weibull stress micromechanical model, or “local approach,” is employed here to quantify these constraint effects. Previous research along these same lines quantifies constraint loss in common fracture specimens relative to strict plane-strain, small-scale yielding conditions with a zero T-stress. Here we present a more practical approach for application within experimental testing programs by comparing directly the two most commonly tested fracture specimens, the single-edge notched bend, SE(B), and the compact tension, C(T), specimens. Developers of testing standards may thus choose a “reference” specimen then correct values measured with other specimens to the adopted reference configuration.     

Mapping the "forbidden" transverse-optical phonon in single strained silicon (100) nanowire

The accurate manipulation of strain in silicon nanowires can unveil new fundamental properties and enable novel or enhanced functionalities. To exploit these potentialities, it is essential to overcome major challenges at the fabrication and characterization levels. With this perspective, we have investigated the strain behavior in nanowires fabricated by patterning and etching of 15 nm thick tensile strained silicon (100) membranes. To this end, we have developed a method to excite the "forbidden" transverse-optical (TO) phonons in single tensile strained silicon nanowires using high-resolution polarized Raman spectroscopy. Detecting this phonon is critical for precise analysis of strain in nanoscale systems. The intensity of the measured Raman spectra is analyzed based on three-dimensional field distribution of radial, azimuthal, and linear polarizations focused by a high numerical aperture lens. The effects of sample geometry on the sensitivity of TO measurement are addressed. A significantly higher sensitivity is demonstrated for nanowires as compared to thin layers. In-plane and out-of-plane strain profiles in single nanowires are obtained through the simultaneous probe of local TO and longitudinal-optical (LO) phonons. New insights into strained nanowires mechanical properties are inferred from the measured strain profiles.     

Solution properties of poly(decylmethacrylate)s

Samples of poly(decylmethacrylate)s (PDMA) of a narrow molecular weight distribution were characterized by means of light-scattering, osmotic pressure, intrinsic viscosity and gelpermeation chromatography. The Kuhn-Mark-Houwink equation for molecularly uniform PDMA in THF at 25°C was calculated to be log [η] (ml/g) = ?2.67 + 0.80 logM (g/mol). The following Θ-solvents were found: 2-propanol, 2-propylacetate, 1-butanol and 1-pentanol. The molecular weight dependence of the demixing behaviour yields a Θ-temperature of 9.6°C for 1-pentanol and of 37.4°C for 1-butanol. Flow curves were measured in various solvents of different thermodynamic quality. A first valuation of the observed non-Newtonian behaviour is given.