1,349 research outputs found
Organizational Mortality of Small Firms: The Effects of Entrepreneurial Age and Human Capital
This paper addresses the issue of internal determination of organizational outcomes. It is argued that in small and simply structured organizations a considerable proportion of the variance in organizational activities and outcomes is associated with individuals. In particular, the paper uses human capital theory to derive hypotheses about individual determinants of organizational mortality. These hypotheses are tested with event-history data of firm registrations and de-registrations in a West German region. The hypotheses are corroborated by the data, but the effects may nonetheless be due to processes linking individual characteristics with organizational performance other than those suggested by the human capital approach
ISS-Experiments of Columnar-to-Equiaxed Transition in Solidification Processing
The main topic of the research project CETSOL in the framework of the Microgravity Application Promotion (MAP) programme of the European Space Agency (ESA) is the investigation of the transition from columnar to equiaxed grain growth during solidification. Microgravity environment allows for suppression of buoyancy-driven melt flow and for growth of equiaxed grains free of sedimentation and buoyancy effects. This contribution will present first experimental results obtained in microgravity using hypo-eutectic AlSi alloys in the Materials Science Laboratory (MSL) on-board the International Space Station (ISS). The analysis of the experiments confirms the existence of a columnar to equiaxed transition, especially in the refined alloy. Temperature evolution and grain structure analysis provide critical values for the position, the temperature gradient and the solidification velocity at the columnar to equiaxed transition. These data will be used to improve modeling of solidification microstructures and grain structure on different lengths scales
A Novel Approach to Space Systems Engineering Education through the Construction of High Altitude Balloons
UC CubeCats is a student organization from the University of Cincinnati dedicated to the education of its members through the development of CubeSats. For every university CubeSat program, there are certain challenges that exist. One of the largest challenges for university CubeSat programs is new member recruitment and retention. New members are often intimidated by the knowledge and experience of more senior members because they have no experience in space systems engineering. In order to mitigate these issues, UC CubeCats has developed a high altitude balloon (HAB) educational program known as the CubeCats Applied Training in Space Exploration (CATiSE) program. By building a HAB, members of the CATiSE program can complete a project using a well-documented space mission engineering process that is similar to the process used for CubeSats. However, unlike CubeSat missions, HAB missions tend to have a shorter lifecycle and lower cost, allowing new members to experiment and learn in a low-risk environment. This CATiSE program includes multiple design reviews, an integration and verification plan, design drawings, and designs of the mission and system architecture. The program was designed to last a full school year, starting with concept exploration in the fall and launch in early April. This is UC CubeCats second HAB launch and the first time the CATiSE program has been implemented. The project to be launched this April, code named project TOYGER, will travel 30km into the stratosphere while the payload measures both radiation energy and light wavelengths. The payload will also take 360-degree images throughout the flight of the balloon. This data will be stored on an external storage device and recovered along with the payload. In order to track the payload, GPS data will be transmitted to the automatic packet reporting system (APRS) as well as a ground station constructed by the members of the CATiSE program. At the end of this 8-month program, new members of UC CubeCats will have a well-founded understanding of the space mission and systems engineering process and will have increased their engineering ability to develop and launch a system that must operate in the harsh environment of space
Numerical error in groundwater flow and solute transport simulation
Models of groundwater flow and solute transport may be affected by numerical error, leading to quantitative and qualitative changes in behavior. In this paper we compare and combine three methods of assessing the extent of numerical error: grid refinement, mathematical analysis, and benchmark test problems. In particular, we assess the popular solute transport code SUTRA [ Voss, 1984 ] as being a typical finite element code. Our numerical analysis suggests that SUTRA incorporates a numerical dispersion error and that its mass-lumped numerical scheme increases the numerical error. This is confirmed using a Gaussian test problem. A modified SUTRA code, in which the numerical dispersion is calculated and subtracted, produces better results. The much more challenging Elder problem [ Elder, 1967 ; Voss and Souza, 1987 ] is then considered. Calculation of its numerical dispersion coefficients and numerical stability show that the Elder problem is prone to error. We confirm that Elder problem results are extremely sensitive to the simulation method used.Juliette A. Woods, Michael D. Teubner, Craig T. Simmons and Kumar A. Naraya
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The cultural grammar of governance: The UK Code of Corporate Governance, reflexivity, and the limits of 'soft' regulation
We identify limits of âreflexive governanceâ by examining the UK Code of Corporate Governance that is celebrated for its âreflexivityâ. By placing the historical genesis of the Code within its politico-economic context, it is shown how its scope and penetration is impeded by a shallow, âsingle loopâ of reflexivity. Legitimized by agency theory, the Code is infused by a âcultural grammarâ that perpetuates relations of shareholder primacy as it restricts accountability to narrow forms of information disclosure directed exclusively at shareholders. Engagement of a deeper, âdouble loopâ reflexivity allows account to be taken of the historical conditions and theoretical conceptions that shape practices and outcomes of corporate governance. Only then is it possible to disclose, challenge and reform narrow conceptions, boundaries and workings of âreflexive governanceâ
The Status Of Two New England âEndemicâ Carices: Carex Elachycarpa And C. Josselynii (Cyperaceae)
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149729/1/tax00494.pd
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