Influence of physical and chemical factors on biological leaching process of copper from printed circuit boards

The article presents the results of the research regarding the biological leaching of this metal from electronic wastes components in the form of printed circuit boards. The purpose of the study was to evaluate the influence of some physical and chemical factors (e.g. pH, oxidation-reduction potential) on bioleaching process and efficiency of copper transfer from solid phase into solution. Bioleaching experiments were carried out with pure cultures of Acidithiobacillus ferrooxidans. The obtained results were discussed

Instructional Leadership, Teaching Quality, and Student Achievement: Suggestive Evidence from Three Urban School Districts

Does providing instruction-related professional development to school principals set in motion a chain of events that can improve teaching and learning in their schools? This report examines professional development efforts by the University of Pittsburgh's Institute for Learning in elementary schools in Austin, St. Paul, and New York City

Mehanizam dezoksidacije tekućeg bakra propuhivanjem argonom

Using the method of argon (with specified oxygen content) blowing, the possibility of copper deoxidation has been considered on the basis of specific thermodynamic data. Despite the oxygen exceeding its equilibrium content in argon, a significant copper deoxidation during blowing has been experimentally observed. The explanation of this phenomenon can be the reaction of oxygen with the crucible material. In the present study, graphite and Al2O3 crucibles were used. The stirring effect of gaseous bubbles promotes passing the substrates to and removing the products from the reaction zone.Koristeći postupak propuhivanja argonom (s određenim sadržajem kisika) razmatrana je mogućnost dezoksidacije bakra na temelju posebnih termodinamičkih podataka. Neovisno, što kisik prelazi ravnotežnu koncentraciju u argonu, praktički je utvrđena znakovita dezoksidacija bakra propuhivanjem argonom. Objašnjenje ove pojave može biti reakcijom kisika s materijalom lonca. U ovom radu rabljeni su lonci od grafita i Al2O3. Utjecaj miješanja plinskih mjehura podupire prolaz substrata i također odstranjivanje produkata iz zone reakcije

Extraction of copper from solution after bioleaching of printed circuit boards (PCBs)

The solvent extraction of copper and iron from bioleaching solutions of PCBs with LIX 860N-IC and next stripping test with H2SO4 were investigated. In test the effect of varying sulfuric acid concentration on stripping rate of Cu and Fe and also phase ratio (O : A) were determined. It was found that the stripping rate of copper increases with the sulfuric acid concentration. The optimal concentration of H2SO4 is suggested to be about 150 g/L and phase ratio O:A = 1:1

Spitzer Mid-Infrared Imaging of Nearby Ultraluminous Infrared Galaxies

We have observed 14 nearby (z<0.16) Ultraluminous Infrared Galaxies (ULIRGs) with Spitzer at 3.6-24 microns. The underlying host galaxies are well-detected, in addition to the luminous nuclear cores. While the spatial resolution of Spitzer is poor, the great sensitivity of the data reveals the underlying galaxy merger remnant, and provides the first look at off-nuclear mid-infrared activity.Comment: To appear in the conference proceedings for Spitzer New Views of the Universe, held Nov. 2004 in Pasadena, C

Star-Like Micelles with Star-Like Interactions: A quantitative Evaluation of Structure Factor and Phase Diagram

PEP-PEO block copolymer micelles offer the possibility to investigate phase behaviour and interactions of star polymers (ultra-soft colloids). A star-like architecture is achieved by an extremely asymmetric block ratio (1:20). Micellar functionality f can be smoothly varied by changing solvent composition (interfacial tension). Structure factors obtained by SANS can be quantitatively described in terms of an effective potential developed for star polymers. The experimental phase diagram reproduces to a high level of accuracy the predicted liquid/solid transition. Whereas for intermediate f a bcc phase is observed, for high f the formation of a fcc phase is preempted by glass formation.Comment: 5 pages, 4 figures, PRL in pres

OBLIGATORY JURISDICTION OF THE SUPREME COURT: APPEALS FROM STATE COURTS UNDER SECTION 237(a) OF THE JUDICIAL CODE

In two ways, a case decided by the state court of last resort may come to the Supreme Court of the United States: by certiorari, or by appeal. Certiorari is discretionary; and the considerations which will lead the Court to grant a writ of certiorari are set out in Rule 38 of the Supreme Court Rules, and are well-known to the practicing bar. Appeal, however, is directed to the obligatory jurisdiction of the Court. Rule 12 merely sets out the procedure to be followed in seeking an appeal; and for his decision as to whether he has substantive basis for an appeal, the practitioner must turn to the Judicial Code and to the cases interpreting it

Mode-division-multiplexing of multiple Bessel-Gaussian beams carrying orbital-angular-momentum for obstruction-tolerant free-space optical and millimetre-wave communication links

We experimentally investigate the potential of using ‘self-healing’ Bessel-Gaussian beams carrying orbital-angular-momentum to overcome limitations in obstructed free-space optical and 28-GHz millimetre-wave communication links. We multiplex and transmit two beams (l = +1 and +3) over 1.4 metres in both the optical and millimetre-wave domains. Each optical beam carried 50-Gbaud quadrature-phase-shift-keyed data, and each millimetre-wave beam carried 1-Gbaud 16-quadrature-amplitude-modulated data. In both types of links, opaque disks of different sizes are used to obstruct the beams at different transverse positions. We observe self-healing after the obstructions, and assess crosstalk and power penalty when data is transmitted. Moreover, we show that Bessel-Gaussian orbital-angular-momentum beams are more tolerant to obstructions than non-Bessel orbital-angular-momentum beams. For example, when obstructions that are 1 and 0.44 the size of the l = +1 beam, are placed at beam centre, optical and millimetre-wave Bessel-Gaussian beams show ~6 dB and ~8 dB reduction in crosstalk, respectively