in this study, the removal of cadmium and lead ions from aqueous solution by nanocrystalline magnetite was investigated. the nanocrystalline magnetite was synthesized by mechanochemical activation of hematite in a high energy planetary mill in argon atmosphere for 45 hours. the ability of the synthesized nanocrystalline magnetite for removal of cd(ii) and pb(ii) from aqueous solutions was studi...

Snow sublimation is an important hydrological process and one of the main causes of the temporal and spatial variation of snow distribution. Compared with surface sublimation, drifting snow sublimation is more effective due to the greater surface exposure area of snow particles in the air. Previous studies of drifting snow sublimation have focused on suspended snow, and few have considered salt...

AIM OF THE STUDY To explore the effects of caffeine and bright light therapy on simulated nighttime driving in sleep-deprived healthy volunteers. PARTICIPANTS AND METHODS Twelve male healthy volunteers aged 20 to 50 years participated in a randomized cross-over study of simulated nighttime driving at a sleep laboratory, followed by recovery sleep with polysomnography at home. The volunteers r...

Kin-selection theory underlies our basic understanding of social evolution [1, 2]. Nest drifting in eusocial insects (where workers move between nests) presents a challenge to this paradigm, since a worker should remain as a helper on her natal colony, rather than visit other colonies to which she is less closely related. Here we reveal nest drifting as a strategy by which workers may maximize ...

In this article, we present a scalable video compression algorithm to deliver higher compression efficiency with limited drifting error. MPEG-4 Fine Granularity Scalability (FGS) compresses the video into a base layer and an enhancement layer. Currently, because the enhancement layer is predicted from the poor-quality base layer, the compression efficiency is low. To improve the compression eff...

The effects of space charge due to slowly drifting ions can be relevant for detectors operated at high intensity, or for relatively low values of the bias voltage. Accurate measurements have been obtained with the liquid krypton calorimeter of the NA48 experiment, from data collected in 1997. The build-up of space charge takes place during the first part of the beam extraction burst, and causes...

We observe a complex change in the hopping exponent value from 1/2 to 1/3 as a function of disorder strength and electron density in a sodium-doped silicon MOSFET. The disorder was varied by applying a gate voltage and thermally drifting the ions to different positions in the oxide. The same gate was then used at low temperature to modify the carrier concentration. Magnetoconductivity measureme...

In this chapter we discuss the role of context in organizing episodic memories. We define context as slowly drifting information (i.e. information that persists over a relatively long time scale in the person's brain; for example, a representation of the person's location). First, we use the Temporal Context Model of memory search (Howard & Kahana, 2002) to illustrate how binding slowly-driftin...

Ion acoustic waves can be excited by electrons drifting relative to the ions in a plasma. This relative drift can be produced, in a collisional plasma, by a static electric field. In the analysis of this instability, which occurs for frequencies well below the ion plasma frequency, the electron inertia term in the momentum equation is typically neglected. A similar assumption has been employed ...