Photocatalytic reduction of carbon dioxide to formaldehyde was investigated on four semiconductor photocatalysts (FeS, FeS/FeS2, NiO and TiO2). The reaction was carried out in continues flow of CO2 gas bubbled into the reactor. Semiconductor photocatalysts were characterized by X-Ray diffraction (XRD) and Diffuse Reflectance Spectroscopic (DRS) methods. Sulfide ion was used as hole scavenger. T...

Photocatalytic reduction of carbon dioxide to formaldehyde was investigated on four semiconductor photocatalysts (FeS, FeS/FeS2, NiO and TiO2). The reaction was carried out in continues flow of CO2 gas bubbled into the reactor. Semiconductor photocatalysts were characterized by X-Ray diffraction (XRD) and Diffuse Reflectance Spectroscopic (DRS) methods. Sulfide ion was used as hole scavenger. T...

Using gene frequency data for 29 polymorphic loci (121 alleles), we conducted a phylogenetic analysis of 26 representative populations from around the world by using the neighbor-joining (NJ) method. We also conducted a separate analysis of 15 populations by using data for 33 polymorphic loci. These analyses have shown that the first major split of the phylogenetic tree separates Africans from ...

We propose a novel method for construction of rectilinear BSP trees for ray shooting acceleration. The trees are contracted according to certain “preferred” set of rays. Particularly, we study ray sets formed by fixing either the direction or the origin of rays. The constructed trees can be used to answer ray shooting query for arbitrary rays, although with higher expected time complexity for r...

Rectilinear Binary Space Partitioning (BSP) trees are often used for solving various types of range searching problems including ray shooting. We propose a novel method for construction of rectilinear BSP trees for a preferred set of ray shooting queries. Particularly, we study ray sets formed by fixing either the direction or the origin of rays. We analyse and discuss the properties of constru...

We present a randomized algorithm for reconstructing directed rooted trees of n nodes and node degree at most d, by asking at most O(dn log n) path queries. Each path query takes as input an origin node and a target node, and answers whether there is a directed path from the origin to the target. Our algorithm is only a factor of O(d log n) from the informationtheoretic lower bound of Ω(n log n...

This paper reviews P´olya urn models and their connection to random trees. Basic results are presented, together with proofs that underly the historical evolution of the accompanying thought process. Extensions and generalizations are given according to chronology: • P´olya-Eggenberger’s urn • Bernard Friedman’s urn • Generalized P´olya urns • Extended urn schemes • Invertible urn schemes ...

Data from storms suggest that the critical wind speed at which trees break is constant (≃42m/s), regardless of tree characteristics. We question the physical origin of this observation both experimentally and theoretically. By combining Hooke's law, Griffith's criterion, and tree allometry, we show that the critical wind speed indeed hardly depends on the height, diameter, and elastic propertie...

There is abundant evidence that evergreen conifers living at high elevations or at high latitudes have longer-lived needles than trees of the same species living elsewhere. This pattern is likely caused by the influence of low temperature in combination with related factors such as a short growing season and low nutrient availability. Because it is not known to what degree such patterns result ...