Related Studies in Long Term Lithium Battery Stability

The continuing growth of the use of lithium electrochemical systems in a wide variety of both military and industrial applications is primarily a result of the significant benefits associated with the technology such as high energy density, wide temperature operation and long term stability. The stability or long term storage capability of a battery is a function of several factors, each important to the overall storage life and, therefore, each potentially a problem area if not addressed during the design, development and evaluation phases of the product cycle. Design (e.g., reserve vs active), inherent material thermal stability, material compatibility and self-discharge characteristics are examples of factors key to the storability of a power source

The End of Innocence: The Effect of California\u27s Recreational Use Statue on Children at Play

One hundred years ago, the idea that children deserved special protection from dangerous conditions found on private property was adopted by both the United States and California Supreme Courts. Due to innocence of children and their inability to perceive possible dangers, landowners were required to provide a higher degree of protection to children than adults. This new and revolutionary idea, later to be labeled the attractive nuisance doctrine, was adopted by the Restatement of Torts in what has been called its most effective single section. However, today in California, a recent decisions has reversed a century of development in the law which has provided protection to children. The duty of care required of a landowner towards the children of this state has returned to that which existed over one hundred years ago

Naval Postgraduate School NPSAT1 Small Satellite

Paper presented at the ESA Small Satellite Systems and Services SymposiumThe NPSAT1 mission, conceived and developed by the Naval Postgraduate School (NPS) Space Systems Academic Group (SSAG), is sponsored and executed by the DoD Space Test Program (SMC SDD). The small satellite is manifested for launch aboard the STP-1 Atlas V Mission due to launch in December 2006. The main objective of the NPSAT1 program is to provide educational opportunities for the offi cer students in the Space Systems Curricula at NPS through the design, testing, integration, and fl ight operations of a small satellite. The 82 kg (180 lbs) satellite will be earth-pointing using a novel, low-cost, 3-axis attitude control scheme. NPSAT1 will provide a platform for a number of spacecraft technology experiments, including a lithium-ion battery, a confi gurable, fault-tolerant processor (CFTP) experiment, and fl ight demonstrations of commercial, off-the-shelf (COTS) components such as microelectromechanical systems (MEMS) rate sensors and a digital camera. The spacecraft command and data handling (C&DH) subsystem is NPS-designed, featuring low-power with error-detection-and-correction (EDAC) memory, an ARM720T microprocessor, and running Linux as the operating system. Two other experiments are provided by the Naval Research Laboratory to investigate ionospheric physics. This paper presents an overview of the spacecraft, its subsystems, and the challenges of a small satellite program in a university environment.Naval Postgraduate School, Monterey, California

Naval Postgraduate School PANSAT: Lessons Learned

AIAA Space 2001 - Conference and Exposition, Albuquerque, NM, August 28-30, 2001The Petite Amateur Navy Satellite (PANSAT) was launched aboard the STS-95 Discovery Shuttle on 29 October 1998. PANSAT was inserted into a circular, low-Earth orbit at an altitude of 550 km and 28.45° inclination on 30 October 1998. PANSAT continues to operate and support the educational mission at NPS even after reaching its two-year design life. The research aspect also continues with the analysis of the accumulated telemetry data, in terms of how well the spacecraft operated over the mission design life. However, the store-and-forward mission using direct sequence spread spectrum was never realized

Inducing Probabilistic Grammars by Bayesian Model Merging

We describe a framework for inducing probabilistic grammars from corpora of positive samples. First, samples are {\em incorporated} by adding ad-hoc rules to a working grammar; subsequently, elements of the model (such as states or nonterminals) are {\em merged} to achieve generalization and a more compact representation. The choice of what to merge and when to stop is governed by the Bayesian posterior probability of the grammar given the data, which formalizes a trade-off between a close fit to the data and a default preference for simpler models (`Occam's Razor'). The general scheme is illustrated using three types of probabilistic grammars: Hidden Markov models, class-based $n$-grams, and stochastic context-free grammars.Comment: To appear in Grammatical Inference and Applications, Second International Colloquium on Grammatical Inference; Springer Verlag, 1994. 13 page

High-Level Production of Amorpha-4,11-Diene, a Precursor of the Antimalarial Agent Artemisinin, in Escherichia coli

BACKGROUND: Artemisinin derivatives are the key active ingredients in Artemisinin combination therapies (ACTs), the most effective therapies available for treatment of malaria. Because the raw material is extracted from plants with long growing seasons, artemisinin is often in short supply, and fermentation would be an attractive alternative production method to supplement the plant source. Previous work showed that high levels of amorpha-4,11-diene, an artemisinin precursor, can be made in Escherichia coli using a heterologous mevalonate pathway derived from yeast (Saccharomyces cerevisiae), though the reconstructed mevalonate pathway was limited at a particular enzymatic step. METHODOLOGY/ PRINCIPAL FINDINGS: By combining improvements in the heterologous mevalonate pathway with a superior fermentation process, commercially relevant titers were achieved in fed-batch fermentations. Yeast genes for HMG-CoA synthase and HMG-CoA reductase (the second and third enzymes in the pathway) were replaced with equivalent genes from Staphylococcus aureus, more than doubling production. Amorpha-4,11-diene titers were further increased by optimizing nitrogen delivery in the fermentation process. Successful cultivation of the improved strain under carbon and nitrogen restriction consistently yielded 90 g/L dry cell weight and an average titer of 27.4 g/L amorpha-4,11-diene. CONCLUSIONS/ SIGNIFICANCE: Production of >25 g/L amorpha-4,11-diene by fermentation followed by chemical conversion to artemisinin may allow for development of a process to provide an alternative source of artemisinin to be incorporated into ACTs