Chemical Recycling of Consumer-Grade Black Plastic into Electrically Conductive Carbon Nanotubes

The global plastics crisis has recently focused scientists’ attention on finding technical solutions for the ever-increasing oversupply of plastic waste. Black plastic is one of the greatest contributors to landfill waste, because it cannot be sorted using industrial practices based on optical reflection. However, it can be readily upcycled into carbon nanotubes (CNTs) using a novel liquid injection reactor (LIR) chemical vapor deposition (CVD) method. In this work, CNTs were formed using black and white polystyrene plastics to demonstrate that off-the-shelf materials can be used as feedstock for growth of CNTs. Scanning electron microscopy analysis suggests the CNTs from plastic sources improve diameter distribution homogeneity, with slightly increased diameters compared with control samples. Slight improvements in quality, as determined by Raman spectroscopy of the D and G peaks, suggest that plastics could lead to increased quality of CNTs. A small device was constructed as a demonstrator model to increase impact and public engagement

Effects of Thermal Annealing on the Properties of Mechanically Exfoliated Suspended and On-Substrate Few-Layer Graphene

Graphene’s novel electrical, optical, and mechanical properties are affected both by substrate interaction and processing steps required to fabricate contacts and devices. Annealing is used to clean graphene devices, but this can lead to doping and defect changes and strain effects. There is often disagreement about which of these effects are occurring and which result in observed changes in Raman spectra. The effects of vacuum annealing on mechanically exfoliated pristine, suspended, and attached thin and thick few-layer graphene on SiO2/Si are investigated here using scanning electron microscopy (SEM), Raman spectroscopy, and atomic force microscopy (AFM). Before annealing, Raman shows that the differences in 2D and G band positions and the appearance of a disorder-induced D band of all regions were mainly because of compressive or tensile structural deformations emerging through mechanical exfoliation instead of charge doping. Annealing at low temperature is sufficient to eliminate most of the defects. However, compressive strain is induced in the sheet by annealing at high temperature, and for thin regions increased substrate conformation leads to the apparent disappearance of the sheets. The intensity ratio of the 2D and G bands also reduces with induced compressive strain, and thus should not be used to detect doping

Formation of atomic tritium clusters and condensates

We present an extensive study of the static and dynamic properties of systems of spin-polarized tritium atoms. In particular, we calculate the two-body |F,m_F>=|0,0> s-wave scattering length and show that it can be manipulated via a Feshbach resonance at a field strength of about 870G. Such a resonance might be exploited to make and control a Bose-Einstein condensate of tritium in the |0,0> state. It is further shown that the quartet tritium trimer is the only bound hydrogen isotope and that its single vibrational bound state is a Borromean state. The ground state properties of larger spin-polarized tritium clusters are also presented and compared with those of helium clusters.Comment: 5 pages, 3 figure

From social contract to 'social contrick' : the depoliticisation of economic policy-making under Harold Wilson, 1974–75

The 1974-79 Labour Governments were elected on the basis of an agreement with the TUC promising a redistribution of income and wealth known as the Social Contract. However, the Government immediately began to marginalise these commitments in favour of preferences for incomes policy and public expenditure cuts, which has led the Social Contract to be described as the 'Social Contrick'. These changes were legitimised through a process of depoliticisation, and using an Open Marxist framework and evidence from the National Archives, the paper will show that the Treasury's exchange rate strategy and the need to secure external finance placed issues of confidence at the centre of political debate, allowing the Government to argue there was no alternative to the introduction of incomes policy and the reduction of public expenditure

The effects of surface stripping ZnO nanorods with argon bombardment

ZnO nanorods are used in devices including field effects transistors, piezoelectric transducers, optoelectronics and gas sensors. However, for efficient and reproducible device operation and contact behaviour, surface contaminants must be removed or controlled. Here we use low doses of argon bombardment to remove surface contamination and make reproducible lower resistance contacts. Higher doses strip the surface of the nanorods allowing intrinsic surface measurements through a cross section of the material. Photoluminescence finds that the defect distribution is higher at the near-surface, falling away in to the bulk. Contacts to the n-type defect-rich surface are near-Ohmic, whereas stripping away the surface layers allows more rectifying Schottky contacts to be formed. The ability to select the contact type to ZnO nanorods offers a new way to customize device behaviour

Forming reproducible non-lithographic nanocontacts to assess the effect of contact compressive strain in nanomaterials

The application of electrical nanoprobes to measure and characterize nanomaterials has become widely spread. However, the formation of quality electrical contacts using metallic probes on nanostructures has not been directly assessed. We investigate here the electrical behaviour of non-lithographically formed contacts to ZnO nanowires (NWs) and develop a method to reproducibly form Ohmic contacts for accurate electrical measurement of the nanostructures. The contacting method used in this work relies on an electrical feedback mechanism to determine the point of contact to the individual NWs, ensuring minimal compressive strain at the contact. This developed method is compared with the standard tip deflection contacting technique and shows a significant improvement in reproducibility. The effect of excessive compressive strain at the contact was investigated, with a change from rectifying to ohmic I–V behaviour observed as compressive strain at the contact was increased, leading to irreversible changes to the electrical properties of the NW. This work provides an ideal method for forming reproducible non-lithographic nanocontacts to a multitude of nanomaterials

Anticancer Properties of a Novel Class of Tetrafluorinated Thalidomide Analogues

The authors thank Scott McMenemy for carrying out preliminary, early studies looking at effects of Gu compounds upon chicken embryology, as well as Charles D. Crowe, Jeffrey E. Roth, and Adam C. Rolt for critical comments on the article. fli1:EGFP zebrafish were obtained from the Zebrafish International Research Center (27). mpo:GFP zebrafish [also termed Tg(MPO:GFP)114] zebrafish were obtained from Dr. Stephen Renshaw, University of Sheffield (Sheffield, South Yorkshire, UK; ref. 29).Peer reviewedPostprin

Enhancement of Multiwalled Carbon Nanotubes’ Electrical Conductivity Using Metal Nanoscale Copper Contacts and Its Implications for Carbon Nanotube-Enhanced Copper Conductivity

Herein, we present an experimental/computational approach for probing the interaction between metal contacts and carbon nanotubes (CNTs) with regard to creating the most efficient, low resistance junction. Tungsten probes have been coated with copper or chromium and the efficiency of nanocontact transport into multiwalled carbon nanotubes (MWCNTs) has been investigated experimentally, using scanning tunneling spectroscopy and nanoscale two-point probe I-V measurements, and in silico, employing DFT calculations. Experimental I-V measurements suggest the relative conductivity of the metal-CNT interaction to be Cu > W > Cr. It has been found that copper when in contact with MWCNTs results in a high density of states at the Fermi level, which contributes states to the conduction band. It was observed that the density of states also increased when chromium and tungsten probes were in contact with CNTs; however, in these cases the density of states increase would only occur under high voltage/high temperature situations. This is demonstrated by an increase in the experimental electrical resistance when compared to the copper probe. These results suggest that in future copper tips should be used when carrying out all intrinsic conduction measurements on CNTs, and they also provide a rationale for the ultraconductivity of Cu-CNT and Cu-graphene composites

The research-teaching nexus: A case study of students' awareness, experiences and perceptions of research

This paper presents a case study of students' awareness, experiences and perceptions of research in a 'new' university in the UK. The findings are based on a questionnaire of almost 200 students and five small group interviews. Many of the students participating in this research perceived clear benefits to their learning from staff research, including being taught by enthusiastic staff, enhanced staff credibility, and the reflected glory of being taught by well-known researchers. However, they also perceived disadvantages, particularly with regard to staff availability, and did not believe that staff research should take priority over their needs as learners. They recognised that their awareness of the nature of research and the development of research skills increased most when they were actively involved in undertaking research projects. Several students also perceived benefits for future employment from their participation in research activities. The questionnaire has been used by several other universities around the world to benchmark their practices. © 2010 Taylor & Francis