Military qualification of a high-reliability, light-weight 24 V/30Ah aircraft battery

The United States Navy has flown Valve Regulated Lead-Acid Batteries (VRLA) for approximately 18 years. The first VRLA aircraft batteries were cylindrical cell design and evolved to a prismatic design to save weight, volume, and to increase rate capability. This paper discusses the next generation of the VRLA aircraft battery. The HORIZON composite grid VRLA design reduces weight, increases high rate performance, and is expected to increase service life. This paper discusses the weight reduction over the present 30 Ah prismatic VRLA aircraft battery design; improvements in high rate engine start performance, and present status of the development effort. Finally, the paper discusses the applications for the 30 Ah composite grid VRLA aircraft battery, and shows the future application opportunities for light-weight VRLA, both in the military and commercially     

Impact Cratering Theory and Modeling for the Deep Impact Mission: From Mission Planning to Data Analysis

The cratering event produced by the Deep Impact mission is a unique experimental opportunity, beyond the capability of Earth-based laboratories with regard to the impacting energy, target material, space environment, and extremely low-gravity field. Consequently, impact cratering theory and modeling play an important role in this mission, from initial inception to final data analysis. Experimentally derived impact cratering scaling laws provide us with our best estimates for the crater diameter, depth, and formation time: critical in the mission planning stage for producing the flight plan and instrument specifications. Cratering theory has strongly influenced the impactor design, producing a probe that should produce the largest possible crater on the surface of Tempel 1 under a wide range of scenarios. Numerical hydrocode modeling allows us to estimate the volume and thermodynamic characteristics of the material vaporized in the early stages of the impact. Hydrocode modeling will also aid us in understanding the observed crater excavation process, especially in the area of impacts into porous materials. Finally, experimentally derived ejecta scaling laws and modeling provide us with a means to predict and analyze the observed behavior of the material launched from the comet during crater excavation, and may provide us with a unique means of estimating the magnitude of the comet’s gravity field and by extension the mass and density of comet Tempel 1.     

Synergetic retrieval of terrestrial AOD from MODIS images of twin satellites Terra and Aqua

Aerosol optical depth (AOD) is one of the most important indicators of atmospheric pollution. It can be retrieved from satellite imagery using several established methods, such as the dark dense vegetation method and the deep blue algorithm. All of these methods require estimation of surface reflectance prior to retrieval, and are applicable to a certain pre-designated type of surface cover. Such limitations can be overcome by using a synergetic method of retrieval proposed in this study. This innovative method is based on the fact that the ratio K of surface reflectance at different angles/geometries is independent of wavelength as reported by Flowerdew and Haigh (1995). An atmospheric radiative transfer model was then established and resolved with the assistance of the ratio K obtained from two Moderate Resolution Imaging Spectroradiometer (MODIS) spectral bands acquired from the twin satellites of Terra and Aqua whose overpass is separated by three hours. This synergetic method of retrieval was tested with 20 pairs of MODIS images. The retrieved AOD was validated against the ground observed AOD at the Taihu station of the AErosol RObotic NETwork (AERONET). It is found that they are correlated with the observations at a coefficient of 0.828 at 0.47 μm and 0.921 at 0.66 μm wavelengths. The retrieved AOD has a mean relative error of 25.47% at 0.47 μm and 24.3% at 0.66 μm. Of the 20 samples, 15 and 17 fall within two standard error of the line based observed AOD data on the ground at the 0.47 μm and 0.66 μm, respectively. These results indicate that this synergetic method can be used to reliably retrieve AOD from the twin satellites MODIS images, namely Terra and Aqua. It is not necessary to determine surface reflectance first.     

Did mineral surface chemistry and toxicity contribute to evolution of microbial extracellular polymeric substances?

Abstract Modern ecological niches are teeming with an astonishing diversity of microbial life in biofilms closely associated with mineral surfaces, which highlights the remarkable success of microorganisms in conquering the challenges and capitalizing on the benefits presented by the mineral-water interface. Biofilm formation capability likely evolved on early Earth because biofilms provide crucial cell survival functions. The potential toxicity of mineral surfaces toward cells and the complexities of the mineral-water-cell interface in determining the toxicity mechanisms, however, have not been fully appreciated. Here, we report a previously unrecognized role for extracellular polymeric substances (EPS), which form biofilms in shielding cells against the toxicity of mineral surfaces. Using colony plating and LIVE/DEAD staining methods in oxide suspensions versus oxide-free controls, we found greater viability of wild-type, EPS-producing strains of Pseudomonas aeruginosa PAO1 compared to their isogenic knockout mutant with defective biofilm-producing capacity. Oxide toxicity was specific to its surface charge and particle size. High resolution transmission electron microscopy (HRTEM) images and assays for highly reactive oxygen species (hROS) on mineral surfaces suggested that EPS shield via both physical and chemical mechanisms. Intriguingly, qualitative as well as quantitative measures of EPS production showed that toxic minerals induced EPS production in bacteria. By determining the specific toxicity mechanisms, we provide insight into the potential impact of mineral surfaces in promoting increased complexity of cell surfaces, including EPS and biofilm formation, on early Earth. Key Words: Mineral toxicity-Bacteria-EPS evolution-Biofilms-Cytotoxicity-Silica-Anatase-Alumina. Astrobiology 12, 785-798.     

Bit-Plane Encoding: A Technique for Source Encoding

This paper describes bit-plane encoding, a technique for reducing redundancy in data gathered in space probes. The results of testing bit-plane encoding on particular data gathered by Explorer XII are summarized, and the technique is compared with alternative schemes for encoding the same data. Bit-plane encoding is intended for use aboard spacecraft. The technique presumes input data in binary form. The encoder implementation consists of a memory to store data samples, a monitor, and a code box. Both the monitor and the code box perform simple operations on binary sequences. Bit-plane encoding is especially useful when the data have an amplitude spectrum which is concentrated in different ranges in different time intervals. With a stored group of 128 samples, bit-plane encoding could be used to describe energetic particle counts gathered by Explorer XII with less than 50 percent as many bits as were actually used, and with no loss of information. The technique also conveniently allows certain useful information destroying operations.     

Web-Enabled Remote Machine Monitoring and Prognostics

1 INTRODUCTION Today's machine tool industries are facing unprecedented challenges brought about by development of outsourcing and low cost manufac-turing in Asia. Manufacturing outsourcing provided many opportu-nities but also added challenges to produce and deliver products with improved productivity, quality, service and costs. Lead times must be cut short to their extreme extend to meet need the changing demands of customers in different regions of the world. Products are required to be make-to-order, which requires a tight control and near-zero downtime of the plant floor, equipment and devices.