Linking information systems and entrepreneurship: A review and agenda for IT‐associated and digital entrepreneurship research

More than 50 years ago, information technology (IT) began to change society, the economy, and industries worldwide. This change has included waves of technological disruption that have been exploited by entrepreneurial actors who seize the associated new opportunities. Research on related phenomena is spread across different disciplines. Recently, there have been calls for further research on the marriage of information systems (IS) and entrepreneurship. We review 292 articles in the IS, entrepreneurship, and general and strategic management literature to create an overview of the IT‐associated entrepreneurship research landscape. On the basis of that review, we elaborate on the different roles that IT can assume to support entrepreneurial operations and value creation in these settings. Our findings suggest that IT plays four major roles in entrepreneurial operations: as a facilitator, making the operations of start‐ups easier; as a mediator for new ventures' operations; as an outcome of entrepreneurial operations; and as a ubiquity, becoming the business model itself. Leveraging these roles of IT, we develop a set of definitions to clear up definition uncertainties surrounding IT‐associated new ventures such as digital start‐ups and digital business models. We also outline a research agenda for IT‐associated entrepreneurship research based on identified roles, types, and gaps.     

Satellite estimation of tropical secondary forest above-ground biomass: Data from Brazil and Bolivia

This paper reports on a test of the ability to estimate above-ground biomass of tropical secondary forest from canopy spectral reflectance using satellite optical data. Landsat Thematic Mapper data were acquired concurrent with field surveys conducted in secondary forest fallows near Manaus, Brazil and Santa Cruz de la Sierra, Bolivia. Measurements of age and above-ground live biomass were made in 34 regrowth stands. Satellite data were converted to surface reflectances and compared with regrowth stand age, biomass and structural variables. Among the Brazilian stands, significant relationships were observed between middle-infrared reflectance and stand age, height, volume and biomass. The canopy reflectance-biomass relationship saturated at around 15.0 kg m^-2, or over 15 years of age (r > 0.80, p < 0.01). In the Bolivian study area, no significant relationship between canopy spectral reflectance and biomass was observed. These contrasting results are probably caused by a low Sun angle during the satellite measurements from Bolivia. However, regrowth structural and general compositional differences between the two study areas could explain the lack of a significant relationship in Bolivia. The results demonstrate a current potential for biomass estimation of secondary forests with satellite optical data in some, but not all, tropical regions. A discussion of the potential for regional extrapolation of spectral relationships and future satellite imagery is included.     

Economic online self-test in the time-triggered architecture

Traditional online self-testing methods in event-triggered systems compromise system responsiveness or result in costly solutions. The testing strategy presented here takes advantage of the properties offered by a time-triggered system to avoid interfering with system responsiveness while maintaining low test overhead     

R-134a compatible lubricants based on C4-C6 esters of pentaerythritol and polyalkyleneglycol

The results of work intended to produce inexpensive, synthetic lubricants compatible with R-134a using waste carboxylic acids C₄-C₆ as the base are presented in this paper. The suitability of the products synthesised was first evaluated considering their physical and chemical properties, and their thermostability determined by the standard Philipp test (sealed glass tube method). Two ester bases were then selected for further testing — a pentaerythritol esterified with C₄-C₆ monocarboxylic acids and a polyalkyleneglycol similarly esterified with monocarboxylic acids C₄-C₆. The base oils chosen were tested for their corrosive action on metals in the presence of water in different concentrations. The pentaerythritol ester proved to have the most advantageous properties at that stage. The results of the laboratory tests have been corroborated by trials conducted on real refrigerating compressor systems. Only the lubricant that was obtained using pentaerythritol esterified with monocarboxylic acids C₄-C₆ as the base withstood the severe test.     

Hg-Cd-Te phase diagram determination by high pressure reflux

A High Pressure Reflux technique has been used for the determination of pressure-temperature phase diagram data for the Hg-Cd-Te system in the pressure range of 9 to 98 atm. For elemental liquid Hg, the variation of vapor pressure with temperature is found to be represented by:ln P_Hg(atm) = 11. 270−7, 149/T (°K) for 789 ≤ T≤1O71°K, which is in good agreement with earlier determinations. The latent heat of vaporization of Hg calculated from this expression is 14. 155 kcal/g-at. For Hg-Te binary melts, the variation of vapor pressure is also found to be in good agreement with data obtained by vapor phase spectroscopy measurements. For pseudobinary Hg_1−xCd_xTe melts, the vapor pressure P at the liquidus temperature varies from 33 atm for x = 0. 20 to 74 atm for x = 0. 60. For these melts, it is found that the activity of Hg, a_Hg = P/P_Hg is constant with an average value of 0. 345 ± 0. 02 0, independent of x and T. The variation of vapor pressure over the pseudobinary melts is therefore represented by:lnP(atm) = 10. 206–7, 149/T (°K), for 0≤x≤ 0. 60 and     

Fuel cell research and development projects in Austria

A five year program on energy storage and fuel cell research has been established in Austria, with the goal to find out what types of batteries and fuel cells could possibly be optimized for commercial applications. In the background there are environmental considerations and others, leading to a future hydrogen economy, also possibly to a use in electric vehicles. The search of the European Space Agency for a suitable system for the HERMES manned space vehicle is contributing considerably to the future prospects. The work in Austria is mainly oriented to low temperature alkaline fuel cell systems and the studies are complementary to a similarly oriented program in Canada, originally started by the Institute for Hydrogen Systems in Mississauga, subsequently continued by private companies in cooperation with the University of Toronto.     

Understanding wide-band MOS transistors

A quantitative understanding of MOS-transistor speed has been slow to emerge because of the absence of a commonly agreed-upon figure of merit for MOS-transistor speed and a lack of familiarity among designers with MOS-amplifier topologies. It is suggested that these problems can be addressed through the use of the unity-gain current frequency (f _T) as a figure of merit for MOS transistors, the use of f_T in the prediction of amplifier bandwidth, and a wider familiarity among designers with practical examples of MOS wideband amplifiers. The use of f_T as a figure of merit is discussed, and the achievable amplifier bandwidths are determined. Increasing the f_T of an MOS device by making the g_m larger or the C_g smaller, or both, is discussed. Wideband CMOS amplifiers are considered     

A Simple Prediction Method for the Surface Tension of Ionic Liquids as a Function of Temperature

In this study, a simple prediction method for the surface tension of ionic liquids (ILs) as a function of temperature is developed. Based on a database of experimental surface tension values collected from the literature, first a prediction scheme for the surface tension at a reference temperature of 298.15 K using only information on the density, molar mass, and anion type of the IL is suggested. By combination of this approach with the temperature dependence of the density, an extended prediction scheme describing the temperature dependence of the surface tension of ILs is recommended. The optimized prediction model for the surface tension allows for the prediction of about 3500 temperature-dependent experimental surface tension data of 226 different ILs with a standard deviation of about 7 %. In comparison with fluid-specific prediction methods found in the literature, the developed simple empirical prediction model requires only easily accessible parameters and can be applied for ILs with arbitrary cation and anion combinations. Thus, the proposed prediction method seems to be a valuable engineering tool for the quantitative estimation of the surface tension of ILs.