Negative differential resistance in nanoscale transport in the Coulomb blockade

Motivated by recent experiments, we have studied transport behavior of coupled quantum dot systems in the Coulomb blockade regime using the master (rate) equation approach. We explore how electron-electron interactions in a donor-acceptor system, resembling weakly coupled quantum dots with varying charging energy, can modify the systems response to an external bias, taking it from normal Coulomb blockade behavior to negative differential resistance (NDR) in the curent-voltage characteristics

Feasibility of using ultrasonic technique to measure the blast furnace lining thickness

Blast furnace process has been the most effective way to produce iron for over 200 years.Throughout the years, large efforts have been put on finding ways to increase the productivity and extend the campaign length. The condition of the refractory lining of a blast furnace plays a very important role to determine its campaign length. Many methods have been employed to measure blast furnace lining thickness including radioisotopes, thermal measurement and core-drilling. Temperature measurement is among the most widely used method for on-line monitoring the profile of the blast furnace inner surface, which is based on numerically solving inverse problem using heat transfer models and readings from thermocouple. Optimization methods are applied to obtain the boundary of the domain iteratively, and hence the computation is very expensive and calculation cannot be very accurate. This paper presents the feasibility of using non-invasive ultrasonic technique in bistatic mode to measure the profile of the refractory liner of the hearth region of blast furnace

Negative Differential Conductance in Nano-junctions: A Current Constrained Approach

A current constrained approach is proposed to calculate negative differential conductance in molecular nano-junctions. A four-site junction is considered where a steady-state current is forced by inserting only the two central sites within the circuit. The two lateral sites (representing e.g. dangling molecular groups) do not actively participate in transport, but exchange electrons with the two main sites. These auxiliary sites allow for a variable number of electrons within the junction, while, as required by the current constrained approach, the total number of electrons in the system is kept constant. We discuss the conditions for negative differential conductance in terms of cooperativity, variability of the number of electrons in the junction, and electron correlations

One-Dimensional Organometallic V-Anthracene Wire and Its B-N Analogue: Efficient Half-Metallic Spin Filters

Using density functional theory, we have investigated the structural, electronic and magnetic properties of infinitely periodic organometallic vanadium-anthracene ([V_2Ant]_\infinity) and [V_4(BNAnt)_2]_\infinity(where BNAnt is B-N analogue of anthracene) for their possible application in spintronics. From our calculations, we find that one-dimensional [V_2Ant]_\infinity and [V_4(BNAnt)_2]_\infinity wires exhibit robust ferromagnetic half-metallic and metallic behavior, respectively. The finite sized $V_6Ant_2$ and $V_6(BNAnt)_2$ clusters are also found to exhibit efficient spin filter properties when coupled to graphene electrodes on either side

The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic précis

<p>Abstract</p> <p>Background</p> <p>The final article in a series of three publications examining the global distribution of 41 dominant vector species (DVS) of malaria is presented here. The first publication examined the DVS from the Americas, with the second covering those species present in Africa, Europe and the Middle East. Here we discuss the 19 DVS of the Asian-Pacific region. This region experiences a high diversity of vector species, many occurring sympatrically, which, combined with the occurrence of a high number of species complexes and suspected species complexes, and behavioural plasticity of many of these major vectors, adds a level of entomological complexity not comparable elsewhere globally. To try and untangle the intricacy of the vectors of this region and to increase the effectiveness of vector control interventions, an understanding of the contemporary distribution of each species, combined with a synthesis of the current knowledge of their behaviour and ecology is needed.</p> <p>Results</p> <p>Expert opinion (EO) range maps, created with the most up-to-date expert knowledge of each DVS distribution, were combined with a contemporary database of occurrence data and a suite of open access, environmental and climatic variables. Using the Boosted Regression Tree (BRT) modelling method, distribution maps of each DVS were produced. The occurrence data were abstracted from the formal, published literature, plus other relevant sources, resulting in the collation of DVS occurrence at 10116 locations across 31 countries, of which 8853 were successfully geo-referenced and 7430 were resolved to spatial areas that could be included in the BRT model. A detailed summary of the information on the bionomics of each species and species complex is also presented.</p> <p>Conclusions</p> <p>This article concludes a project aimed to establish the contemporary global distribution of the DVS of malaria. The three articles produced are intended as a detailed reference for scientists continuing research into the aspects of taxonomy, biology and ecology relevant to species-specific vector control. This research is particularly relevant to help unravel the complicated taxonomic status, ecology and epidemiology of the vectors of the Asia-Pacific region. All the occurrence data, predictive maps and EO-shape files generated during the production of these publications will be made available in the public domain. We hope that this will encourage data sharing to improve future iterations of the distribution maps.</p

First qarterly Review Meeting - A Project SN-0-101

Minutes of the First Quarterly meeting are reported

Evaluation of Bolt-Pull- Through Strength of Carbon Fibre Composite

This report presents the results of bolt-pull-through tests conducted under room temperature13; and hot wet condition, on quasi isotropic and another optimised lay-up ('K' laminate with 100'13; countersunk holes in round disc-shaped specimens in as-received condition, as well as moisture13; I saturated condition: The specimens had central countersunk holes of nominal diameter - 5mm13; and 6mm Load %4 as applied through steel and titanium bolts with 10(ixB0; countersunk13; head,normai to the plane of the disc, while it was supported along the periphery by a speciaii.13; designed fixture13; Tests were carried out under stroke control using microprocessor based controller on Instron i13; i 1 341 load frames The load displacement graphs suggest higher load carrying capacity in13; bearing for titanium matenal compared to steel material under room temperature condition The13; maximum load to failure was higher for specimens with 6mm diameter and 4 4mm thickness13; under both types of testing environmen

Fatigue Crack Growth Properties of Aluminium- Lithium Alloy 1441

This report presents the results of a fatigue and fracture data generation program to evaluate an aluminum-lithium alloy 1441 developed as part of the indigenisation13; program initiated by ADA. The material processing was carried out jointly by Defence Metallurgical Research Laboratory, Hyderahad and Russian Agency, VIAM. The material was supplied in three different thickness: 8 mm, 2 mm and 1.2 mm. Both 2 and 1.2 mm thick sheets were supplied in two variants: clad and unclad. Fatigue crack growth rate tests were conducted on this material at room temperature, both under constant amplitude and Mini LCA spectrum loading. The results are compared with those of an13; Aluminum-Copper alloy BS: L73. Alloy 1441 possesses fatigue crack growth resistance comparable with that of alloy BS: L73 and is fairly isotropic in mechanical property, in contrast with other Al-Li alloys, like 8090, 2090