Maturity Assessment of Space Plug-and-Play Architecture

Space Plug-and-Play Architecture (SPA), as defined by the SPA subject matter experts, is a spacecraft development architecture that includes technology and standards developed to facilitate simplified design, assembly, and test of spacecraft systems using modular components to reduce spacecraft development cost and schedule. There is a need to assess the maturity of SPA to determine its benefits and return on investment. SPA, being a system and a combination of technology and standards, poses challenges for the maturity assessment. In this thesis, the author presents the methodologies to assess the maturity of SPA, using the existing Technology Readiness Level (TRL) process for technology and developing new process for the standards. The TRL process is applied to the technology components and the SPA system. The proposed process for assessing the maturity of the product development standards is similar to the TRL process, but tailored for applicability to standards. The methodology for assessing the maturity of SPA standards is based on the premises of what was done and under what conditions. Applying these methodologies to assess the maturity of SPA gives a complete picture of the status of SPA development, which is used to estimate the cost to reach full maturity with more accuracy.http://archive.org/details/maturityassessme1094532878Captain, United States Air Forc

The effect of soil amendments and soil structure on minimizing constraints of lowland soils on growth of mungbean and peanut under glasshouse condition

Crop diversification following wet season rice is one avenue of increasing agricultural productivity in Cambodia. Lowland rice soils have numerous physical and chemical constraints to non-rice crop production. A glasshouse pot experiment was conducted during dry season from January to April 2010 at the Cambodian Agricultural Research and Development Institute (CARDI). An omission pot trial investigated the effect of soil structure, soil fertility, soil pH, lime, and straw mulching on growth of mungbean and peanut. Results showed that at flowering time, the omissions of rice straw mulching and chemical fertilizer application had the largest effect followed by omission of cow manure application on growth of mungbean and peanut, while omission of either lime or disturbed soil structure reduced growth, but the effect was small and not significant. At final harvest stage, the omission of chemical fertilizer application still has the large effect on the total dry matter of mungbean and peanut, followed by lime application and straw mulching

Wet cultivation in lowland rice causing excess water problems for the subsequent non-rice crops in the Mekong region

Crop diversification is advocated for improvement of income of lowland rice farmers in the Mekong region, including Laos, Cambodia and Thailand. One common problem of adding non-rice crops after wetland rice is excess water caused by reduced drainage associated with the hard pan that is commonly created to store water in the paddy for the rice crop. This paper firstly describes the water balance in the lowland fields particularly on how deep percolation is decreased by the hard pan, and the effect of wet cultivation on soil compaction and water availability in the subsequent crops such as mungbean. Experimental work in Cambodia shows how non-rice crops such as mungbean and peanut often fail completely or partially due to excess water. The common experience is complete failure of the early wet season non-rice crop when rain started earlier and the lowland paddy is saturated with water, but also non-rice crops often do not grow well due to shallow root systems confined to the top soil above the hard pan. Destructing the hard pan may help non-rice crops, but the process is expensive and may have an adverse effect on subsequent rice crops. Experimental work has also demonstrated that where irrigation water is available, irrigation is often not effective as it causes soil saturation in the top soil. Ways to minimize the excess water problem are discussed