Formation of tungsten oxide nanostructures by laser pyrolysis: stars, fibres and spheres

In this letter, the production of multi-phase WO3 and WO3-x (where x could vary between 0.1 and 0.3) nanostructures synthesized by CO2-laser pyrolysis technique at varying laser wavelengths (9.22-10.82 mm) and power densities (17-110 W/cm2) is reported. The average spherical particle sizes for the wavelength variation samples ranged between 113 and 560 nm, and the average spherical particle sizes for power density variation samples ranged between 108 and 205 nm. Synthesis of W18O49 (= WO2.72) stars by this method is reported for the first time at a power density and wavelength of 2.2 kW/cm2 and 10.6 μm, respectively. It was found that more concentrated starting precursors result in the growth of hierarchical structures such as stars, whereas dilute starting precursors result in the growth of simpler structures such as wires

Efficient Photodegradation of Thiocyanate Ions in Mining Wastewater Using a ZnO-BiOI Heterojunction

Mining industries have long relied on cyanidation as the primary method for gold extraction, but this process generates thiocyanates as a problematic byproduct, posing challenges for wastewater treatment and recycling. The stability of thiocyanates makes their reduction or elimination in mining wastewater difficult. In this study, a p-n heterojunction of ZnO and BiOI was created and evaluated for its ability to photodegrade thiocyanate ions under simulated solar conditions. Various analytical techniques revealed a highly porous structure with a sponge-like morphology and agglomeration in the synthesized heterojunction. The compound exhibited crystalline patterns without impurity peaks, a slight red shift in absorbance, and Type IV isotherm adsorption. The synthesized heterostructure achieved the complete destruction of thiocyanate ions in less than 30 min. The investigation of different process parameters indicated that the destruction of the contaminant by the heterostructure was influenced by the initial thiocyanate concentration, which decreased as the thiocyanate concentration increased. The peak photodestruction reaction was observed at pH 7. By applying a pseudo-first-order kinetic model, it was found that increasing the catalyst mass to 15 mg raised the rate constant from 0.188 to 0.420 min−1, while increasing the pH to 10 led to a 3.5-fold reduction. The strong correlation between the observed data and the predicted values of the pseudo-first-order kinetic model was indicated by the observed (R2) values. The findings of this study hold potential significance for mining industries, as it offers a potential solution for eliminating cyanide and thiocyanates from mining wastewater. The elimination of thiocyanate generation in the cyanidation process is crucial for mining companies, making this study valuable for the industry

Language skills, peer rejection, and the development of externalizing behavior from kindergarten to fourth grade

Background: Children with poorer language skills are more likely to show externalizing behavior problems, as well as to become rejected by their peers. Peer rejection has also been found to affect the development of externalizing behavior. This study explored the role of peer rejection in the link between language skills and the development of externalizing behavior. Methods: Six hundred and fifteen (615) children were followed from kindergarten to grade 4. Receptive language skills were measured with the Peabody Picture Vocabulary Test in grade 2. Teachers reported externalizing behavior and peer reports of social rejection were measured annually. Results: Children with poorer receptive language skills showed increasing externalizing behavior, while children with better receptive language skills showed decreases in externalizing behavior. Children with poorer receptive language skills experienced peer rejection most frequently. The link between receptive language skills and the development of externalizing behavior was mediated by the development of peer rejection. Findings suggested that this mediational link applied mostly to boys. Conclusion: Children with poorer language skills are at increased risk of becoming rejected by mainstream peers, which adds to the development of externalizing behavior. © 2010 The Authors. Journal of Child Psychology and Psychiatry. © 2010 Association for Child and Adolescent Mental Health

Improved efficiency of organic solar cells using Au NPs incorporated into PEDOT:PSS buffer layer

Au based plasmonic phenomenon inside the hole transport layer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) of an organic solar cell based on blend of poly(3-hexylthiophene) (P3HT) and [6:6]-phenyl-C61-butyric acid (PCBM) is investigated. The concentration of the Au nanoparticles synthesized by wet chemical reduction is one of the key factors to strong light trapping when the spherical gold nanoparticles are blended into the PEDOT:PSS solution. Studies of the influence of the concentration of nanoparticles distribution in the PEDOT:PSS were carried out using UV–Vis spectroscopy and atomic force microscopy. Electrical characteristics of the pristine device and of device with metallic nanostructures were analyzed from J –V characteristics to observe the plasmonic effects on the performance in the P3HT:PCBM organic solar cells. The origin of the photocurrent enhancements with varying Au nanoparticles concentrations on PEDOT:PSS are discussed.The University of theWitwatersrand, Material Physics Research Institute, School of Physics & Chemistry; and MMU facilities at Wits, NRF and Material Energy Research Group (MERG).http://scitation.aip.orgcontent/aip/journal/advaam2017Physic

Tuning Magnetic Properties of a Carbon Nanotube-Lanthanide Hybrid Molecular Complex through Controlled Functionalization

Molecular magnets attached to carbon nanotubes (CNT) are being studied as potential candidates for developing spintronic and quantum technologies. However, the functionalization routes used to develop these hybrid systems can drastically affect their respective physiochemical properties. Due to the complexity of this systems, little work has been directed at establishing the correlation between the degree of functionalization and the magnetic character. Here, we demonstrate the chemical functionalization degree associated with molecular magnet loading can be utilized for controlled tuning the magnetic properties of a CNT-lanthanide hybrid complex. CNT functionalization degree was evaluated by interpreting minor Raman phonon modes in relation to the controlled reaction conditions. These findings were exploited in attaching a rare-earth-based molecular magnet (Gd-DTPA) to the CNTs. Inductively coupled plasma mass spectrometry, time-of-flight secondary ion mass spectrometry and super conducting quantum interference device (SQUID) measurements were used to elucidate the variation of magnetic character across the samples. This controlled Gd-DTPA loading on the CNT surface has led to a significant change in the nanotube intrinsic diamagnetism, showing antiferromagnetic coupling with increase in the Weiss temperature with respect to increased loading. This indicates that synthesis of a highly correlated spin system for developing novel spintronic technologies can be realized through a carbon-based hybrid material

Mopanie Residence (SketchUp 3D model)

3D virtual model. OR Use Sketchup to access model. Download Sketchup from http://sketchup.google.com/download/.Created by 3rd year B.Sc.(Arch) student, University of Pretoria, 2009.http://web.up.ac.za/res.asp?ipkCategoryID=3977&sub=0&parentid=20&subid=113&ipklookid=

Mopanie Residence (poster)

Poster created using models created by Artlantis software.Created by 3rd year B.Sc.(Arch) student, University of Pretoria, 2009.http://web.up.ac.za/res.asp?ipkCategoryID=3977&sub=0&parentid=20&subid=113&ipklookid=