The history of utility-interactive photovoltaic generation

A history is presented of utility photovoltaic generation. Material from readily available publications is discussed and referenced chronologically to show the reader how utility-interactive photovoltaic generation reached its present status     

Shipping and Handling of Pesticide Cargoes: the Need for Change

Of all the dangerous goods carried at sea, pesticide cargoes are unique in the dangers which they pose to the environment. In 1991, the UN International Maritime Goods Code was amended to require that specified chemicals be labelled as 'marine pollutants'. In addition, packaging must now allow for immersion in seawater and include attempts at salvage. The potential hazards of pesticide cargoes have been illustrated by a number of accidents involving shipping and there is an urgent need to expedite the provisions of the code. Also, many pesticides which are exported are not registered for use in the country of origin. A good case exists for linking the provisions of the code to the registration process and to the 'prior informed consent'procedure and developing 'convention'.     

Effect of Heat-Treatment Temperature on the Properties of a Lithium Aluminosilicate Glass

The effects of isochronal heat treatments on the properties of a lithium aluminosilicate glass have been measured. Heat treatment of the base glass at temperatures between 700° and 1100°C initially results in phase separation of the glass, followed by the formation of β-quartz solid solution ( ss ) at about 850°C. The β-quartz( ss ) converts to β-spodumene in the temperature range between 950°C and 1000°C. The dependence of the properties of the material on the heat-treatment temperature is controlled by phase separation below 850°C, by the rapid crystallization of β-quartz( ss ) between 850°C and 900°C, and by the lack of change in morphology with heat treatment above 900°C. The effects of heat treatment on the properties of this material are explained on the basis of the changes in the composition and morphology of the residual amorphous and crystalline phases.     

The effects of flumazenil on the antinociceptive actions of morphine in rats

The 8-fluoro-5,6-dihydro-5-methyl-6-oxo-4H-imidazol[1,5-a][1,4]benzodiazepine-3-carboxylic acid ethyl ester (Flumazenil)-morphine interaction on analgesia (acute pain model, tail-flick test) was tested after intraperitoneal (IP) and intrathecal (IT) routes of administration in female rats. Analgesia was enhanced by the concurrent administration of Flumazenil with morphine (IP), in a dose-related way. Flumazenil alone (IP) did not produce analgesia. In contrast, morphine analgesia was not enhanced by Flumazenil by the IT route. These data demonstrate that Flumazenil enhances morphine-mediated antinociception by mechanisms that are likely to involve benzodiazepine receptors at sites other than the spinal cord.     

Thermooptic Coefficients of Some Standard Reference Material Glasses

The thermooptic coefficients, i.e., the change in refractive index with temperature (d n /d T ), of four National Institute of Standards and Technology standard reference material (SRM) glasses have been measured over the range of 25° to 125°C. The thermooptic coefficients of all four glasses, NBS-710 (a soda-lime silicate), SRM-711 (a lead silicate), SRM-717 (a borosilicate), and SRM-739 (silica) are positive and range in value from 2 × 10⁻⁶/K to 9.8 × 10⁻⁶/K. The differences in the d n /d T of these glasses arise from differences in the coefficient of thermal expansion and the temperature coefficient of the electronic polarizability.     

The influence of carbon morphologies and concentrations on the rheology and electrical performance of screen-printed carbon pastes

Screen-printing inks containing various morphologies of carbon are used in the production of a variety of printed electronics applications. Particle morphology influences the rheology of the ink which will affect the deposition and therefore the electrical performance of a printed component. To assess the effect of both carbon morphology and concentration on print topography and conductivity, screen printable carbon inks with differing loading concentrations of graphite, carbon black and graphite nanoplatelets (GNPs) were formulated, printed and characterised, with rheological and novel print visualisation techniques used to elucidate the mechanisms responsible. Carbon morphology had significant effects on the packing of particles. The smaller carbon black particles had more interparticle interactions leading to better conductivities, but also higher ink viscosities and elasticities than the other morphologies. Increases in carbon concentration led to increases in film thickness and roughness for all morphologies. However, beyond a critical point further increases in carbon concentration led to agglomerations of particles, mesh marking and increases in surface roughness, preventing further improvements in the print conductivity. The optimal loading concentrations were identifiable using a custom-made screen-printing apparatus used with high speed imaging for all morphologies. Notable increases in filamentation during ink separation were found to occur with further increases in carbon concentration beyond the optimum. As this point could not be identified using shear rheology alone, this method combined with shear rheology could be used to optimise the carbon concentration of screen-printing inks, preventing the use of excess material which has no benefit on print quality and conductivity.

     

Experimental demonstration of a single-molecule electric motor

For molecules to be used as components in molecular machines, methods that couple individual molecules to external energy sources and that selectively excite motion in a given direction are required. Significant progress has been made in the construction of molecular motors powered by light and by chemical reactions, but electrically driven motors have not yet been built, despite several theoretical proposals for such motors. Here we report that a butyl methyl sulphide molecule adsorbed on a copper surface can be operated as a single-molecule electric motor. Electrons from a scanning tunnelling microscope are used to drive the directional motion of the molecule in a two-terminal setup. Moreover, the temperature and electron flux can be adjusted to allow each rotational event to be monitored at the molecular scale in real time. The direction and rate of the rotation are related to the chiralities of both the molecule and the tip of the microscope (which serves as the electrode), illustrating the importance of the symmetry of the metal contacts in atomic-scale electrical devices.     

Measurement of un-ionized ammonia in complex mixtures

The toxicity of un-ionized ammonia, NH3 (aq), in anaerobic digestion of high-nitrogen wastes has been researched extensively. Previous estimates of NH3 (aq) concentration have relied on a simple speciation approach, based only on the acid dissociation constant and the sample pH and total ammonia concentration. The distinction between concentration and chemical activity has generally not been made, despite the potential for resulting errors in the calculation of NH3 (aq) concentration, and the greater applicability of activity to toxicity work. The currently accepted approach for estimating NH3 (aq) concentration is based on assumptions that are not valid in digested animal manure or other concentrated wastes. This work presents an approach for directly measuring NH3 (aq) activity in complex mixtures using gaseous/aqueous equilibrium across microporous tubing. Application of this approach to anaerobic digester samples confirms that the currently accepted approach is not accurate; it overestimated NH3 (aq) activity in unaltered samples by 45-200%. Previous work on the toxicity of ammonia to methanogenesis has probably overestimated the tolerance of consortia to NH3 (aq), due to overestimation of concentrations. The method introduced here is expected to be useful in a range of research on ammonia toxicity and volatilization.