Nanostructured Dense ZrO2 Thin Films from Nanoparticles Obtained by Emulsion Precipitation

Nonagglomerated spherical ZrO₂ particles of 5–8 nm size were made by emulsion precipitation. Their crystallization and film-forming characteristics were investigated and compared with nanosized ZrO₂ powders obtained by sol–gel precipitation. High-temperature X-ray diffraction indicated that the emulsion-derived particles are amorphous and crystallize at 500°C into tetragonal zirconia, which is stable up to 1000°C. Crystallite growth from 5–20 nm occurred between 500°–900°C. Films of 6–75 nm thickness were made by spreading, spin coating, and controlled deposition techniques and annealed at 500°–600°C. The occurrence of t -ZrO₂ in the emulsion-precipitated powder is explained by the low degree of agglomeration and the corresponding low coarsening on heating to 500°–800°C, whereas the agglomerated state of the sol–gel precipitate powder favors the occurrence of the monoclinic form of zirconia under similar conditions.     

Understanding fibroblast activation protein (FAP): Substrates,activities, expression and targeting for cancer therapy

Fibroblast activation protein (FAP) is best known for its heightened expression in tumour stroma. This atypical serine protease has both dipeptidyl peptidase and endopeptidase activities, cleaving substrates at a post-proline bond. FAP expression is difficult to detect in non-diseased adult organs, but is greatly upregulated in sites of tissue remodelling, which include liver fibrosis, lung fibrosis, atherosclerosis, arthritis, tumours and embryonic tissues. Due to its restricted expression pattern and dual enzymatic activities, FAP is emerging as a unique therapeutic target. However, methods to exploit and target this protease are advancing more rapidly than knowledge of the fundamental biology of FAP. This review highlights this imbalance, emphasising the need to better define the substrate repertoire and expression patterns of FAP to elucidate its role in biological and pathological processes.     

Impolite landscapes? The influence of local economic and cultural factors in garden history: a case study of tyne and wear

The study of garden history derives from roots planted firmly in art history. As it has matured as a subject it has gradually begun to look more broadly at what constitutes an historic landscape and make links with other disciplines of landscape study. This paper reports on a study of parks and gardens in the metropolitan county of Tyne and Wear. It argues that to understand the garden history of this area, traditionally unfashionable and essentially industrial, a restricted art historical approach is inadequate. An understanding of a complex web of economic and cultural factors is required. Issues which emerged in the research are explored through a series of themes based on site types.     

Population Decline in Non-Metropolitan Australia: Impacts and Policy Implications

Despite the overall growth of the Australian population there are significant levels of population decline in some regions. Depopulation has often been caused by technological and economic change. In some cases this trend creates a vicious cycle of population loss, service decline and further out-migration. The public policy maker is faced with a difficult balance between equity and efficiency considerations as regional population decline leads to increasing per capita costs of service and infrastructure provision. This paper highlights regions in Australia which are experiencing depopulation, examining causes, impacts and policy implications.     

Charge Photogeneration for a Series of Thiazolo‐Thiazole Donor Polymers Blended with the Fullerene Electron Acceptors PCBM and ICBA

Photoinduced charge separation in bulk heterojunction solar cells is studied using a series of thiazolo‐thiazole donor polymers that differ in their side groups (and bridging atoms) blended with two acceptor fullerenes, phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) and a fullerene indene‐C60 bisadduct (ICBA). Transient absorption spectroscopy is used to determine the yields and lifetimes of photogenerated charge carriers, complimented by cyclic voltammetry studies of materials energetics, wide angle X‐ray diffraction and transmission electron microscopy studies of neat and blend film crystallinity and photoluminescence quenching studies of polymer/fullerene phase segregation, and the correlation of these measurements with device photocurrents. Good correlation between the initial polaron yield and the energetic driving force driving charge separation, ΔE_CS is observed. All blend films exhibit a power law transient absorption decay phase assigned to non‐geminate recombination of dissociated charges; the amplitude of this power law decay phase shows excellent correlation with photocurrent density in the devices. Furthermore, for films of one (relatively amorphous) donor polymer blended with ICBA, we observe an additional 100 ns geminate recombination phase. The implications of the observations reported are discussed in terms of the role of materials' crystallinity in influencing charge dissociation in such devices, and thus materials design requirements for efficient solar cell function.     

Analysis of the historical collapse of an abandoned underground chalk mine in 1961 in Clamart (Paris,France)

In chalk mines, the method of room and pillar mining has been widely used in France. Yet, many large collapses have occurred during or after their exploitation, with the collapse of Clamart (south of Paris, France) being well known as one of the most catastrophic. Today, 50 years after the collapse, the main causes of the event are still not well understood. This paper presents a back-analysis of the case study, using both an empirical approach and a numerical approach. Based on a set of hypotheses, an empirical approach and 3D numerical modeling have indicated a plausible scenario that may explain the collapse: The large collapse may have been caused by a lack of bearing capacity of the pillars and the sudden rupture of a hard limestone bed on which the load would have accumulated until overload occurred. The bed weakness between the two mine levels may also have had an influence on the mine’s general lack of stability. Moreover, under the given hypothesis, the study shows a very low influence of the water table due to flooding of the mine.

     

Plutonium Loading of Prospective Grouped Actinide Extraction (GANEX) Solvent Systems based on Diglycolamide Extractants

The Grouped Actinide Extraction (GANEX) process is being developed for actinide recycling within future nuclear fuel cycles. Interactions between potential solvents and macro-concentrations of plutonium are one of the most important issues in defining the GANEX process. Surprisingly, plutonium loading of diglycolamide (DGA) based solvents such as tetra-octyl DGA (TODGA) causes precipitation rather than a conventional third phase, in direct contrast to results with U(VI), Th(IV) or lanthanide ions. Various DGA based solvent systems have been screened for their plutonium loading capacity and 0.2 M TODGA with 0.5 M DMDOHEMA in a kerosene diluent is selected as the optimum solvent formulation of those tested. Plutonium can be relatively easily stripped from this solvent using aqueous acetohydroxamic acid but this is very acid dependent in the low acidity region.     

A case study using lightweight formalism to review an information system specification

This paper presents an approach using derivation of a formal model to review the diagram‐and‐text specification of an information system specification, based on concepts from the formal and structured integrated method, SAZ. Extraction of the formal model is outlined, and the approach is illustrated with a simplified extract from an industrial trial. Some empirical findings from the trial, which reviewed a pre‐existing commercial specification, are presented, and the general applicability of the review approach is discussed. Copyright © 2001 John Wiley & Sons, Ltd.