Power systems related to operations of a landed planetary capsule

Power systems related to Mars landing capsul

Defective Chemokine Production in T-Leukemia Cell Lines and its Possible Functional Role

Peripheral blood lymphocytes and T-cell clones produced nanogram quantities of the chemokines RANTES, MIP-lα, MIP-lβ, MCP-l, IL-8 and GRO-α as well as the motogenic cytokine HGF. In contrast, various T-leukemia cell lines at different stages of differentiation did not produce the same chemokines/cytokines. In order to study the possible functional importance of the poor chemokine production different T-cell lines were compared with respect to development of motile forms and migration on extracellular matrix components in the absence and presence of various chemokines. RANTES, MIP-1α, MIP-1β, IL-8, GRO-α and lymphotactin did not augment the development of motile forms including the size and appearance of the pseudopodia activity of the T-leukemia cell lines. The T-cell lines migrated spontaneously on/to fibronectin in a Boyden chamber assay system. Chemokines augmented the migration of the T-leukemia cell lines on fibronectin in the Boyden system in a chemotactic fashion with peak responses at 10 to 50 ng/ml. Thus, the production of chemokines is defective, in neoplastic T-lymphocytes. The defective chemokine production does not seem to play any major role for the basic locomotor capacity of the cells but may modulate the responsiveness to exogenous chemokines

Study of the Anisotropic Frictional and Deformation Behavior of Surfaces Textured with Silvr Nanorods

Friction is one of the most common and influential mechanical interactions of two structures on both the macroscopic scale and especially the microscopic scale. On the microscopic scale, friction becomes the prime component of mechanical forces exerted on devices. Frictional anisotropy is an interesting characteristic of certain materials and can be used to control frictional properties in various applications. In this study, we measured the anisotropic frictional behavior of two silver (Ag) thin films: a continuous film and a thin film consisting of tilted nanorods angled at an average angle of 70o to the surface normal. Scratches, eight microns in length, were performed on the films with normal loads ranging from 50 µN to 8,000 µN using a conical tip with a 100 micron tip radius. The coefficient of friction (COF) of the tilted nanorods was measured for scratches performed along, against, and perpendicular to the tilt direction. In addition, the deformation of the individual scratches was visually characterized with a scanning electron microscope (SEM). The tilted nanorods demonstrated significant frictional anisotropy with the COF of scratches performed against the tilt direction being over 30 percent lower than those performed along the tilt direction. Furthermore, for normal loads up to 2000 µN, the tilted nanorod sample displayed a lower COF than the thin film for scratches performed against the tilt direction. Visual deformation analysis showed a large increase in damage as the normal load was systematically raised from 50 µN to 8000 µN. In addition, the deformations of the nanorods are shown to be dependent on the direction of the scratch

Guidelines and consideration for construction contractors using commodity futures as hedging tools for mitigating construction material pricing risk

Many would argue that risk management is the single most important element of a construction contractor's business enterprise. A significant risk to a contractor’s profitability is increased costs of construction materials. In many cases construction materials are the largest single component of a construction project budget. Contractors generally utilize contingency funds or contractual price adjustments clauses to address the risk associated with changes in construction material pricing. However, the use of contingency and contractual mechanisms comes at a cost. The additional costs are especially detrimental in construction markets that are competitively bid, because higher bid prices result in winning fewer jobs. An alternative risk mitigation is the use of commodity futures to hedge the risk of increasing construction material prices. A hedge is strategy for limiting losses by holding a portfolio of noncorrelated assets. The research of this study evaluates the application of commodity futures for hedging material pricing risk in the construction industry. Through statistical analysis and simulation studies this research concludes that utilizing commodity futures as a hedging strategy is effective risk mitigation against increased construction material costs. In addition, through a literature review this study explains the fundamentals of the commodity future market, and presents the mechanics of trading commodity futures. A guideline for using commodity futures as a hedging tool is included in this study.Title Page / Table of Contents / List of Exhibits / List of Appendices / Abstract / Introduction / Literature Review / Research Methodology / Analysis / Results / Hedging Guidelines & Considerations / Conclusions / Recommendations for Further Research / Acknowledgements / Appendice