Irradiance calibration with solar diffuser

The sun's energy is used in combination of movable and fixed diffuser plates, windows and apertures which are positioned in a series of test sequences (modes) for reflectance monitoring and calibration without the use of man-made sources. There are three embodiments, or implementations, of the invention--one embodiment uses two diffusers--a working diffuser and a secondary diffuser--the second embodiment uses three diffusers, a working diffuser, a secondary diffuser and a reference diffuser--and the third embodiment uses two diffusers--a working diffuser and a secondary diffuser, the latter also functioning as a cover for the working diffuser. The movable diffusers are mounted on rotatable cones and, in all embodiments, the sun is blocked from reaching the diffusers when not in use. Thus, the sun is used as a stable source for calibration and monitoring and the sun/diffuser combination is used in such a way that the response of all elements of the optical subsystem of the TOMS can be unambiguously and efficiently characterized with high accuracy and precision

Setting the Theoretical Foundations of Importing Research: Past Evaluation and Future Perspectives

Although prior efforts have been made to review research on importing, an updated, integrated, and chronological assessment of its theoretical evolution is lacking. This study critically investigates the theoretical foundations of importing research using a comprehensive review of 321 importing-related articles published during the 1960–2010 period. The analysis reveals that, although in general this research adopts a certain theoretical perspective, a notable part of it is not theoretically anchored. Of those studies that rely on theories, the most commonly used are the neoclassical microeconomic model, the behavioral model, and transaction cost economics. These theories were mainly associated with international buying behavior, importer–exporter relationships, and strategic aspects of importing. The study also identifies a range of other important topics that could be investigated using extant theories. In addition, the authors propose several other theories not previously employed, such as the institutional, stakeholder, and resource dependence theories, to be used in the study of new research issues. Finally, the authors suggest several actions toward theory advancement, including the need to integrate multiple theoretical paradigms, adjust theory to different environments, combine quantitative and qualitative inputs, cross-fertilize ideas from various disciplines, and periodically assess developments in the importing literature