Keeping up with dynamics of next generation missiles

ABSTRACT In an effort to comply with the increasing quest for higher dynamics and increased inertia of test units modern HWILsystems are employing increasingly larger hydraulic actuators. A new 3-axis flight motion simulator with increased performance is reviewed. Also future trends of the HWIL-systems are discussed both for hydraulic and electric actuators. Some drawbacks of hydraulic systems, including increased acoustic noise levels and extensive service and maintenance requirements from the hydraulic power unit, limited stroke of the actuators for large systems and poor small signal performance are discussed and compared to the performance of electric actuators. Can the electric actuators advantages make up for the power density performance gap

Keeping up with dynamics of next generation missiles

ABSTRACT In an effort to comply with the increasing quest for higher dynamics and increased inertia of test units modern HWILsystems are employing increasingly larger hydraulic actuators. A new 3-axis flight motion simulator with increased performance is reviewed. Also future trends of the HWIL-systems are discussed both for hydraulic and electric actuators. Some drawbacks of hydraulic systems, including increased acoustic noise levels and extensive service and maintenance requirements from the hydraulic power unit, limited stroke of the actuators for large systems and poor small signal performance are discussed and compared to the performance of electric actuators. Can the electric actuators advantages make up for the power density performance gap

Thionein (apometallothionein) can modulate DNA binding and transcription activation by zinc finger containing factor Spl

AbstractA number of transcription factors contain so-called zinc finger domains for the interaction with their cognate DNA sequence. It has been shown that removal of the zinc ions complexed in these zinc fingers abrogates DNA binding and transcription activation. Therefore we wanted to test the hypothesis that the activity of transcription factors could be regulated by physiological chelators of zinc. A prominent candidate for such a chelator is the Cys-rich protein thionein (apometallothionein) that is inducible by heavy metal loads, and by other environmental stimuli. Here we show with DNA binding and in vitro transcriptions assays that thionein indeed can inactive the zinc finger-containing Spl in a reversible manner. By contrast, transcription factor Oct-l, which binds DNA via a homeo-domain, i.e. a helix-turn-helix motif not involving zinc ions, is refractory to thionein action. We propose that modulation of intracellular thionein concentration is used for the coordinated regulation of a large subset of genes whose transcription depends on zinc finger proteins

Keeping up with dynamics of next generation missiles

In an effort to comply with the increasing quest for higher dynamics and increased inertia of test units modern HWIL-systems are employing increasingly larger hydraulic actuators. A new 3-axis flight motion simulator with increased performance is reviewed. Also future trends of the HWIL-systems are discussed both for hydraulic and electric actuators. Some drawbacks of hydraulic systems, including increased acoustic noise levels and extensive service and maintenance requirements from the hydraulic power unit, limited stroke of the actuators for large systems and poor small signal performance are discussed and compared to the performance of electric actuators. Can the electric actuators advantages make up for the power density performance gap

Cost-effective sol-gel synthesis of porous CuO nanoparticle aggregates with tunable specific surface area

CuO nanoparticles (NPs) are applied in various key technologies, such as catalysis, energy conversion, printable electronics and nanojoining. In this study, an economic, green and easy-scalable sol-gel synthesis method was adopted to produce submicron-sized nanoporous CuO NP aggregates with a specific surface area > 18 m²/g. To this end, a copper-carbonate containing precursor was precipitated from a mixed solution of copper acetate and ammonia carbonate and subsequently calcinated at T ≥ 250 °C. The thus obtained CuO nanopowder is composed of weakly-bounded agglomerates, which are constituted of aggregated CuO NPs with a tunable size in the range of 100–140 nm. The CuO aggregates, in turn, are composed of equi-axed primary crystallites with a tunable crystallite size in the range of 20–40 nm. The size and shape of the primary CuO crystallites, as well as the nanoporosity of their fused CuO aggregates, can be tuned by controlled variation of the degree of supersaturation of the solution via the pH and the carbonate concentration. The synthesized submicron-sized CuO aggregates can be more easily and safely processed in the form of a solution, dispersion or paste than individual NPs, while still offering the same enhanced reactivity due to their nanoporous architecture.ISSN:2045-232

Spermiotoxicity and embryotoxicity of heavy metals in the echinoid Paracentrotus lividus

Spermio- and embryotoxicities of Cu, Ag, Cd, and Hg were investigated in Paracentrotus lividus, the dominant echinoid species of the Mediterranean. Spermiotoxicity was studied by assessing the effects of sperm exposure on fertilization rate (FR) as well as on the induction of transmissible damages to the offspring. Embryotoxicity was studied by assessing developmental defects in larvae exposed to the tested metals throughout their development. Sperm exposures resulted in significant decreases of FR, depending on both metal concentration and duration of the exposure. Lowest spermiotoxic concentrations recorded when sperm were exposed for 75 min to the metals were 10−7 M Hg(II), 10−6 M Ag(I), 10−5 M Cu(II), and 10−5 M Cd(II). Tested metals did not exert any transmissible damage to spermatozoa that could result in larval malformations in the offspring, even for concentrations that dramatically reduced FR. Single-element exposures of embryos for 72 h resulted in developmental defects whose occurrence and severity showed a steep dose dependence, indicating that once a threshold is reached, any further increase in toxicant concentration rapidly enhances the impairment of target function(s). Those observations suggest the involvement of a saturable protective mechanism. Lowest observed embryotoxic concentrations of the metals were 10−7 M Hg(II), 2.5 × 10−7 M Ag(I), 5 × 10−7 M Cu(II), and 10−5 M Cd(II) and are in the range of concentrations reported in heavily polluted marine environments. Thus, the possibility of impairment of echinoid development actually exists in metal-contaminated marine environments, possibly threatening echinoid populations in those environments.FLWINinfo:eu-repo/semantics/publishe