Hafnium clad fuels for fast spectrum BWRs

We show that by use of hafnium cladding, a fast neutron spectrum is achievable in the top of uprated BWRs. Monte Carlo calculations have been made for Hf clad inert matrix nitride and low fertile MOX fuels, with fuel segments located in the upper part of an uprated BWR, where the coolant void fraction exceeds 70%. The nitride fuel results in the hardest neutron spectrum, but the low fertile MOX fuel still yields fission probabilities for even neutron number nuclides similar to those of sodium cooled reactors. The inert matrix nitride fuel configuration yields high burning rates, permitting to stabilise TRU inventories with less than 50% BWR cores of the here suggested type in the power park. The core with low fertile MOX fuel is less efficient, but still a zero net producer of TRU. Fuel and coolant temperature feedbacks are affected by introduction of absorbing elements in the fuel, but remain within acceptable ranges for the low fertile MOX fuel. Although control rod worths are reduced, shutdown margins are sufficient to ensure sub-criticality in cold conditions. From a materials point of view, the behaviour of hafnium clad MOX fuel would be similar to zircalloy clad MOX fuel already used extensively in nuclear industry. Thus, if dynamic stability of the core can be ensured, the here proposed fuel may be considered as a low cost solution for transmutation of minor actinides on industrial scale.     

Performance analysis of power generating sludge combustion plant and comparison against other sludge treatment technologies

Expectations on wastewater sludge treatment and recovery of its energy and material contents are increasing because of the tightening legislation and the obligation to reduce environmental impacts of sludge disposal. The objective of this study was to analyze the performance of a heat and power generating sludge combustion plant from technical and economical viewpoints and to compare the studied concept to optional sludge treatment technologies. The plant performance was modeled for sewage sludge produced by approximately 200,000 inhabitants. Two plant sizes below 1000 kWe range were investigated, the smaller plant using sludge as the only fuel and the larger plant with wood chips as the additional fuel. The plants were compared with heat-only plants of similar size. The payback periods for heat-only plants are typically shorter than with the cogenerating plants because the changes in plant investment affect stronger the economy than do the revenues from selling electricity. The gate fee of sludge treatment has the strongest effect on the payback period. The selection of the plant concept (cogeneration, heat only or pure electricity generation) is, however, affected more by the local demand of heat and electricity than pure economy. The selection of the optimal technology for sludge treatment is a complicated task. The studied concept can be the optimal choice, for example, if there is no cement kiln or co-combustion possibility near the source of sludge, if there is no land enhancement demand for the digested sludge, or if the energy surplus from combustion compared to anaerobic digestion is considered more valuable than nutrient recovery possibility from digestion. If the new technology concept is found competitive, it still has to meet the challenge of acceptability from the business, social and cultural points of view.     

用背反射提高染料敏化太阳能电池光电转换效率的研究

当光射入染料敏化太阳能电池(DSCs)时,有部分光不能被染料、电解液、导电玻璃等吸收,这部分光将透过电池而未被利用,本研究利用普通镀铝玻璃镜做为背底,将这部分透射光通过背反射重新射入电池来提高DSCs的光电转换效率.研究结果表明,背反射能大幅度提高DSCs的短路电流,短路电流的增加率随着测试遮光罩开孔尺寸的增加而增加,并且随纳米TiO2薄膜厚度的增加而降低.     

Aerosol analysis of residual and nanoparticle fractions from spray pyrolysis of poorly volatile precursors

The quality of aerosol‐produced nanopowders can be impaired by micron‐sized particles formed due to non‐uniform process conditions. Methods to evaluate the quality reliably and fast, preferably on‐line, are important at industrial scales. Here, aerosol analysis methods are used to determine the fractions of nanoparticles and micron‐sized residuals from poorly volatile precursors. This is accomplished using aerosol instruments to measure the number and mass size distributions of Liquid Flame Spray‐generated alumina and silver particles produced from metal nitrates dissolved in ethanol and 2‐ethylhexanoic acid (EHA). The addition of EHA had no effect on silver, whereas, 5% EHA concentration was enough to shift the alumina mass from the residuals to nanoparticles. The size‐resolved aerosol analysis proved to be an effective method for determining the product quality. Moreover, the used on‐line techniques alone can be used to evaluate the process output when producing nanopowders, reducing the need for tedious off‐line analyses. © 2016 American Institute of Chemical Engineers AIChE J, 63: 881–892, 2017     

Effects of silane and the lowering of pH on the properties of phenol–formaldehyde resol resins and resin coatings

Phenol–formaldehyde resol resins were modified by the addition of silane (3‐aminopropyltriethoxysilane) and the lowering of pH (formic acid). The effects of the modifications on the properties of the resins during storage were studied through comparison with the parent resins and by viscosity measurements, NMR spectroscopy, ultraviolet–visible spectroscopy, and differential scanning calorimetry. Resin coatings on paper were prepared to determine the influence of discoloration of the resin solution on the color of the cured resin. A decrease in the pH of the NaOH‐catalyzed resin solutions lightened the color of the solutions and corresponding coatings, whereas silane additions made the coatings slightly more yellow. The lowering of pH increased the viscosities and decreased the reactivities of the resin solutions compared with the unmodified reference resins during storage. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1933–1941, 2007     

Coherent Out‐of‐Core Point‐Based Global Illumination

We describe a new technique for coherent out‐of‐core point‐based global illumination and ambient occlusion. Point‐based global illumination (PBGI) is used in production to render tremendously complex scenes, so in‐core storage of point and octree data structures quickly becomes a problem. However, a simple out‐of‐core extension of a classical top‐down octree building algorithm would be extremely inefficient due to large amount of I/O required. Our method extends previous PBGI algorithms with an out‐of‐core technique that uses minimal I/O and stores data on disk compactly and in coherent chunks for later access during shading. Using properties of a space‐filling Z‐curve, we are able to preprocess the data in two passes: an external ID‐sort and an octree construction pass.     

Publication patterns in the social sciences and humanities: evidence from eight European countries

Scientometrics - The increasing number of open-access full-text scientific documents promotes the transformation from metadata- to content-based studies, which is more detailed and semantic. Along...     

Oxidation of accident tolerant fuel candidates

In this study, the oxidation of various accident tolerant fuel candidates produced under different conditions have been evaluated and compared relative to the reference standard – UO₂. The candidates considered in this study were UN, U₃Si₂, U₃Si₅, and a composite material composed of UN–U₃Si₂. With the spark plasma sintering (SPS) method, it was possible to fabricate samples of UN with varying porosity, as well as a high-density composite of UN–U₃Si₂?(10%). Using thermogravimetry in air, the oxidation behaviors of each material and the various microstructures of UN were assessed. These results reveal that it is possible to fabricate UN to very high densities using the SPS method, such that its resistance to oxidation can be improved compared to U₃Si₅ and UO₂, and compete favorably with the principal ATF candidates, U₃Si₂, which shows a particularly violent reaction under the conditions of this study, and the UN–U₃Si₂?(10%) composite.     

Unruly Representation: Materiality,indexicality and agency of the photographic trace

This article examines photographic representation as a material and indexical trace caused by photons reflected and/or emitted from the photographed objects. It argues that the contested idea of indexicality remains relevant to the photograph despite the digitalization of the photographic process. It also suggests that the trace works as an affordance which renders ambiguous the photographic representation as re-presentation. The material trace provides an anchorage point for the presence of the photographed objects. However, the very same presence destabilizes the photograph’s function as a representation and renders its status controversial. Therefore, the photograph both is and is not a representation. As a much-celebrated guarantee of photographic truth, the trace works, in fact, as an element of perpetual epistemological controversy and also as an affordance for philosophical, ontological and poetic analysis.     

Stable linker peptides for a cellulose-binding domain-lipase fusion protein expressed in Pichia pastoris

Fusion proteins composed of a cellulose-binding domain fromNeocallimastix patriciarum cellulase A and Candida antarcticalipase B were constructed using different linker peptides. Theaim was to create proteolytically stable linkers that were ableto join the functional modules without disrupting their function.Six fusion variants containing linkers of 4–44 residueswere expressed in Pichia pastoris and analysed. Three variantswere found to be stable throughout 7-day cultivations. The cellulose-bindingcapacities of fusion proteins containing short linkers wereslightly lower compared with those containing long linkers.The lipase-specific activities of all variants, in solutionor immobilized on to cellulose, were equal to that of the wild-typelipase.