Polythiophene and oligothiophene systems modified by TTF electroactive units for organic electronics

The aim of this review is to give an update on current progress in the synthesis, properties and applications of thiophene-based conjugated systems bearing tetrathiafulvalene (TTF) units. We focus mostly on the synthesis of poly- and oligothiophenes with TTF moieties fused to the thiophene units of the conjugated backbone either directly or via a dithiin ring. The electrochemical behaviour of these materials and structure–property relationships are discussed. The study is directed towards the development of a new type of organic semiconductors based on these hybrid materials for application in organic field effect transistors and solar cells

An adjoint for likelihood maximization

The process of likelihood maximization can be found in many different areas of computational modelling. However, the construction of such models via likelihood maximization requires the solution of a difficult multi-modal optimization problem involving an expensive O(n3) factorization. The optimization techniques used to solve this problem may require many such factorizations and can result in a significant bottle-neck. This article derives an adjoint formulation of the likelihood employed in the construction of a kriging model via reverse algorithmic differentiation. This adjoint is found to calculate the likelihood and all of its derivatives more efficiently than the standard analytical method and can therefore be utilised within a simple local search or within a hybrid global optimization to accelerate convergence and therefore reduce the cost of the likelihood optimization

Electrochromic properties of a poly(dithienylfuran) derivative featuring a redox-active dithiin unit

A teraryl monomer containing a 1,4-dithiin-furan central unit has been synthesised and characterised by single crystal X-ray crystallography. The di(thienyl)furan monomer 11 was successfully polymerised electrochemically and shown to possess a lower electrochemical band gap than its terthiophene analogue (1.97 eV cf. 2.11 eV). The electrochromic properties of this polymer proved to be superior to PEDOT, with fast switching and reversible colour transformation at high colour contrast (CE = 212 cm(2) C-1 cf. 183 cm(2) C-1 for PEDOT at 95% optical switch)

Evaluation of the parfait blanket concept for fast breeder reactors

"January 1974."Also issued as a Ph. D. thesis by the first author and supervised by the second and third author, MIT, Dept. of Nuclear Engineering, 1974Includes bibliographical references (pages 261-264)An evaluation of the neutronic, thermal-hydraulic, mechanical and economic characteristics of fast breeder reactor configurations containing an internal blanket has been performed. This design, called the parfait blanket concept, employs a layer of axial blanket fuel pellets at the core midplane in the fuel pins of the inner enrichment zone; otherwise, the design is the same as that of the conventional LMFBR's to which the parfait configuration was compared. Two significant advantages were identified for the parfait blanket concept relative to the conventional design. First, the parfait configuration has a 25% smaller peak fast flux which reduces wrapper tube dilation by 37% and fuel element elongation by 29%; and second, axial and radial flux flattening contribute to a 7. 6% reduction in the peak fuel burnup. Both characteristics significantly diminish the problems of fuel and metal swelling. Other advantages identified for a typical parfait design include: a 25% reduction in the burnup reactivity swing, which reduces control rod requirements; a 7% greater overpower operating margin; an increased breeding ratio, which offsets the disadvantage of a higher critical mass; and more favorable sodium voiding characteristics which counteract the disadvantage of an 8% smaller power Doppler coefficient. All other characteristics investigated were found to differ insignificantly or slightly favor the parfait design.U.S. Atomic Energy Commission contract AT(11-1)-225

Chair Design Affects How Older Adults Rise from a Chair

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111137/1/j.1532-5415.1996.tb06402.x.pd

van der Waals epitaxy of monolayer hexagonal boron nitride on copper foil : growth, crystallography and electronic band structure

We investigate the growth of hexagonal boron nitride (h-BN) on copper foil by low pressure chemical vapour deposition (LP-CVD). At low pressure, h-BN growth proceeds through the nucleation and growth of triangular islands. Comparison between the orientation of the islands and the local crystallographic orientation of the polycrystalline copper foil reveals an epitaxial relation between the copper and h-BN, even on Cu(100) and Cu(110) regions whose symmetry is not matched to the h-BN. However, the growth rate is faster and the islands more uniformly oriented on Cu(111) grains. Angle resolved photoemission spectroscopy measurements reveal a well-defined band structure for the h-BN, consistent with a band gap of 6 eV, that is decoupled from the copper surface beneath. These results indicate that, despite a weak interaction between h-BN and copper, van der Waals epitaxy defines the long range ordering of h-BN even on polycrystalline copper foils and suggest that large area, single crystal, monolayer h-BN could be readily and cheaply produced

Traceability in the UK Seafood chain

Traceability in seafood supply chains is vital for ensuring food safety, proving legality and tackling illegal, unregulated and unreported (IUU) fishing, and verifying sustainability. UK seafood supply chains vary in complexity. As complexity across a supply chain increases, the importance of seafood transparency and traceability at each stage of the supply chain increases.The project sought examples of different supply chains of seafood landed in the UK to examine the current levels of traceability across the supply chain, examples of best practice, challenges to traceability and improvements that could be recommended for implementation in UK seafood supply chains. Case studies were sought from three UK seafood supply chains: i) Case study A: (Demersal) Dover (common) sole landed into ports in South West England; ii) Case Study B: (Pelagic) Mackerel from vessels landing into Peterhead, Scotland; and iii) Case Study C: (Shellfish) Brown crab / lobster from vessels landing into Bridlington, England. An initial seafood supply chain mapping exercise was undertaken for each case study through stakeholder structured interviews followed by in-depth semi structured interviews with actors across the supply chain.Key recommendations for improving traceability within the UK seafood supply chain include:• Focus on improving traceability up to the point of first sale.• Definitions of traceability need to more clearly stated to stakeholders.• Digitalise and integrate information systems.• Improve stakeholder engagement around data submission.• Minimise duplication of catch reporting by MMOs and IFCAs• Improvements to traceability systems are needed to allow for the distinction between sustainable versus non-sustainably caught seafood.• Increase transparency in how data submissions are used to increase data accuracy• Improve monitoring of wholesale markets.It should be acknowledged that the current approaches to improving traceability in seafood supply chains are already implementing some of the recommendations highlighted in this report. The recommendations from this report should serve to strengthen areas of traceability work that are already ongoing and to provide further impetus for development of best practice across UK seafood supply chains

Traceability in the UK Seafood chain

Traceability in seafood supply chains is vital for ensuring food safety, proving legality and tackling illegal, unregulated and unreported (IUU) fishing, and verifying sustainability. UK seafood supply chains vary in complexity. As complexity across a supply chain increases, the importance of seafood transparency and traceability at each stage of the supply chain increases.The project sought examples of different supply chains of seafood landed in the UK to examine the current levels of traceability across the supply chain, examples of best practice, challenges to traceability and improvements that could be recommended for implementation in UK seafood supply chains. Case studies were sought from three UK seafood supply chains: i) Case study A: (Demersal) Dover (common) sole landed into ports in South West England; ii) Case Study B: (Pelagic) Mackerel from vessels landing into Peterhead, Scotland; and iii) Case Study C: (Shellfish) Brown crab / lobster from vessels landing into Bridlington, England. An initial seafood supply chain mapping exercise was undertaken for each case study through stakeholder structured interviews followed by in-depth semi structured interviews with actors across the supply chain.Key recommendations for improving traceability within the UK seafood supply chain include:• Focus on improving traceability up to the point of first sale.• Definitions of traceability need to more clearly stated to stakeholders.• Digitalise and integrate information systems.• Improve stakeholder engagement around data submission.• Minimise duplication of catch reporting by MMOs and IFCAs• Improvements to traceability systems are needed to allow for the distinction between sustainable versus non-sustainably caught seafood.• Increase transparency in how data submissions are used to increase data accuracy• Improve monitoring of wholesale markets.It should be acknowledged that the current approaches to improving traceability in seafood supply chains are already implementing some of the recommendations highlighted in this report. The recommendations from this report should serve to strengthen areas of traceability work that are already ongoing and to provide further impetus for development of best practice across UK seafood supply chains

Predicting the Impact of Climate Change on Cheat Grass (Bromus tectorum) Invasibility for Northern Utah: A GIS and Remote Sensing Approach

Cheat grass (Bromus tectorum) invasibility represents a serious threat to natural ecosystems dominated by sagebrush (Artemisia tridentata). Ecosystem susceptibility to annual grass invasion seems to be driven by specific biophysical conditions. The study was conducted in Rich County, Utah, where cheat grass invasion is not yet an apparent problem, but an imminent invasion might be just a matter of time (temporal scale) to meet spatial variations in environmental conditions (spatial scale). Literature review and expert knowledge were used to define biophysical variables and their respective suitability ranges of where cheat grass takeover might occur. GIS, remote sensing and logistic regression-statistical analyses were employed to estimate probability of cheat grass invasion along environmental gradients. GIS procedures were used to spatially predict areas prone to be invaded by cheat grass under present climatic conditions (model prediction power was 47 percent). Afterwards, simulated climatic change projections (for 2099 year) from the Community Climatic System Model (CCSM-3) were used to model the invasibility risk of cheat grass. The 2099 cheat grass prediction map showed a favorable reduction of around 25 percent in the areas affected by cheat grass invasion, assuming that climate changes occurred as predicted by the CCSM model. The location of highly predisposed areas can be useful to alert managers and define where resources might be allocated to reduce a potential invasion and preserve native rangeland ecosystems