Foreign object damage (FOD) has been identified as one of the primary life limiting factors for fan and compressor blades. A comprehensive study is reported here on the fatigue crack growth behaviour in a generic aerofoil specimen of Ti–6Al–4V alloy treated by laser shock peening (LSP) prior to FOD, using both experimental and numerical approaches. 3D finite element analyses have been carried out to simulate the FOD impact on the LSPed aerofoil specimen and to derive an effective stress intensity factor range, considering both the 3D residual stress fields due to LSP and FOD and crack closure due to the compressive residual stresses. The effective stress intensity factor was then used to provide a rational analysis of fatigue crack growth in a complex residual stress field under low cycle, high cycle and combined low and high cycle fatigue condition.

Crack Growth Under Simulated Flight Cycles In Laser Shock Peened Ti-6AL4V Alloy S. Zabeen1a, M. Preuss1b, P.J. Withers1c, S. Spanrad2d, J. Tong2e, J. Schofield3f, T. Lippmann4 1. School of Materials, University of Manchester, Grosvenor St, Manchester M1 7HS, UK 2. Mechanical & Design Engineering, Department of Mechanical and Design Engineering, Anglesea Building, Anglesea Road, University of Portsmouth, Portsmouth, PO1 3DJ, UK, 3. Rolls-Royce plc. Institute of Materials Research, GKSS Research Centre, D-21502 Geesthacht, Germany

The current study investigates the effect of foreign object damage (FOD) on the pre-existing compressive residual stress field associated with laser shock peening (LSP) and its evolution upon combined LCF/HCF cycling. FOD was introduced onto an aerofoil-shaped specimen that had been previously LSP treated through ballistic impacts at angles of 0° and 45° to the leading edge. It is shown that the FOD notch created by 45° impact was asymmetric in shape and smaller in depth compared to that created at 0° impact. Significant through thickness compression was introduced parallel to the leading edge as a result of the LSP process. The residual strain distribution was mapped around the FOD notch by synchrotron X-ray radiation. The results show predominantly compressive stresses ahead of the notch, being greater for the 0 compared to 45 impact. No significant stress relaxation was observed after a combined (1000 HCF cycles superimposed on 1 LCF cycle) cycle.

Excavations at Billingsgate in the City of London in 1982 uncovered extensive remains of the 17th- century buildings of Botolph Wharf. Changes to the structures, and an exceptionally rich array of artefacts datable to 1620-66 (the Great Fire of London), are attributable to the tenancy of Thomas Soane, grocer, and later of his widow. The artefacts and buildings demonstrate differing domestic and warehouse uses just before the Fire, and complement the documentary record. When taken with plan evidence from the Treswell surveys of c. 1612, the excavations prompt discussion of how warehouses fitted into the configuration of buildings in the pre-Fire City.

In a previous study (Li et al., 2001. J Exp Zool 290:18-30) a nude mouse model was established to investigate deer antler development. In that study we found nude mice could support the singularly implanted antlerogenic periosteum (AP) to form pedicle-like, but not antler-like, bony protuberances. To further develop the model and at the same time to use the updated model for the investigation of antler formation, three experiments were carried out in this study. The results showed that (1) antler-like protuberances were successfully induced on the nude mouse heads via subcutaneous co-transplantation of AP and deer skin, and subsequent exposure through wounding of the deer xenografts; (2) deer skin epidermis and its attached half thickness of dermis were sufficient to interact with the AP, and the interactions were capable of transforming adult scalp skin into velvet; (3) the putative initial inductive molecules were primarily derived from the AP cellular layer, rather than fibrous layer; (4) initiation of the ossification center in the avascular cartilage of each mouse "antler" took place via metaplasia, rather than classical endochondral ossification. Further research is required to identify means for effective stimulation of calcification of the "mouse antlers" in order to create the opportunity to investigate antler regeneration using the nude mouse model. Overall, the nude mouse model, once further developed, has the potential to become a powerful tool to study underlying mechanism of antlerogenesis and organogenesis/regeneration in general.

In an attempt to reduce the dye and fabric damage caused by manganese complexes of 1,4,7-trimethyl-1,4,7-triazacyclononane previously employed as low temperature bleaching catalysts in domestic laundry formulations, a novel series of analogues with chelating phosphonic acid pendant arms has been prepared. In order to identify possible bleaching catalysts more rapidly, and with reduced environmental impact, a bleaching screening test has been developed that seeks to identify metal–ligand combinations that may represent active low temperature bleaching catalysts. Of the four methylphosphonic acid containing ligands tested in combination with a range of transition metal salts, only two metal–ligand combinations with manganese salts displayed sufficient activity to take forward for further testing, with the efficacy of the ligands in the oxidative removal of stains decreasing as the number of pendant arms increased. Both of the active ligand systems produced greater dye damage than existing bleach activators, with the ligand with a single methylphosphonic acid pendant arm being particularly aggressive towards stained fabrics sensitive to oxidative damage. This indicates that the systematic addition of chelating pendant arms, whilst tempering the activity of the complexes as bleaching catalysts, unfortunately does not provide a solution to the problem of dye and fabric damage. In contrast to the activity observed in the bleaching screen, the activity of the manganese–ligand combinations in the epoxidation of some alkene substrates was found to bear no relation to the number of methylphosphonic acid pendant arms.

The development of a novel reactive unsaturated interfacial modifier for filled (magnesium hydroxide, aluminium hydroxide and calcium carbonate) polyolefins is reviewed. Initial work explored maleimide functional candidate molecules including 1,3-phenylene dimaleimide (1,3-PDM) and a range of linear alkyl dimaleimides. Most of the dimaleimides were very effective interfacial modifiers in polypropylene and poly(ethylene-co-vinylacetate) (18% w/w vinylacetate) based composites. However, the dimaleimides caused the composites to have a distinct pink/brown colouration apart from when the maleimide groups were spaced by a C12 alkyl chain. The problem with colour and high effective dosage prompted a switch to unsaturated carboxylic acid based systems. The performance of a range of unsaturated carboxylic acids and the hexafunctional monomer trimethylolpropane triacrylate are reviewed, together with a novel oligomeric unsaturated carboxylic acid (OUCA) based system developed by the Noveon Division of Lubrizol Limited. The data obtained from this series of interfacial modifiers, and adsorption studies on 1,3-PDM and OUCA, afforded some insight into the competing factors (such as the strength of adsorption versus ability to form a polymerised interfacial layer and the ability to react with matrix chains) that significantly affect the coupling performance of interfacial modifiers.

Two new end-capped sexithiophene derivatives (10a and 10b) have been synthesised and characterised by absorption spectroscopy, cyclic voltammetry and UV-vis spectroelectrochemistry. Both oligomers undergo two reversible, sequential oxidation processes (10a: E1½ = +0.61 V, E2½ = +0.97 V; 10b: E1½ = +0.70 V, E2½ = +0.91 V vs. Ag/AgCl) and the electronic band gaps of the materials are ca. 2.2 eV (solid state). Sexithiophene 10a has been incorporated as an electron donor material, with C60 as acceptor, in a bilayer photovoltaic device. The power conversion efficiency is a modest 0.12%, whilst the maximum IPCE at 350 nm gave an external quantum efficiency of ca. 12%.

Coupling agents play a key role in modifying and enhancing the mechanical properties of filled polymer systems. Dr. John Schofield of Noveon Specialty Additives describes a novel coupling agent technology, and outlines work that has identified a range of performance benefits that can be derived from the use of the technology.

The log analysis of a web site can be used to guide performance improvement. Log analysis identifies which resources on a website are often accessed and those that are not. A log analysis can provide cost justification for a corporate web presence. We describe the log analysis of a large integrated delivery system in New York City from its launch May 1, 2001, through April 30, 2002. During this first year there were 428753 sessions with 1322153 page views. An analysis of page views, exclusive of the default home page, revealed that the pages most frequently visited were related to job opportunities (22.4%, 120086 of 428753), general information ('About') (8.5%, 45355), St. Vincent's Hospital Manhattan (8.3%, 44630), graduate medical education and allied health (8.1%, 43317), facilities (7.2%, 38677), web site search (6.4%, 34322), and physician finder (4.3%, 22910). The web site facilitated 1,980 online job applications. Health information received 15356 page views from 1793 visits. The re-design of the site for year 2 promoted the more frequently selected links, flattened the navigational architecture, and enabled access to all web pages within two to three mouse clicks of the home page. Lessons learned in the process of developing and maintaing a health care organization web site are shared in the case study.

BACKGROUND:T-cell receptor (TCR)-gamma gene rearrangements provide a specific clonal marker for T-cell malignancies of both the alpha beta and gamma delta varieties. A polymerase chain reaction (PCR)-based method was used in this study for investigation of clonal TCR-gamma gene rearrangements in a patient with a classical presentation of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) that subsequently progressed into an indolent form of dermal T-cell lymphoma.METHODS:TCR gene rearrangements in patients with cutaneous T-cell lymphoma (CTCL) were examined using conventional Southern blot analysis and a newly developed PCR-based technique for clonal TCR gene rearrangements. The oligoprimers amplified rearranged V gamma and J gamma segments (including the N region) of the TCR-gamma gene, and PCR products were resolved using high resolution nondenaturing polyacrylamide gel electrophoresis.RESULTS:The authors' results demonstrated good correlation between the two techniques in 10 patients with CTCL (9 patients with C beta and 1 patient with delta 2 rearrangements) and 10 control subjects. The PCR-based technique allowed the authors to detect the presence of an identical T-cell clone in all skin nodules, but not in the original lymph node affected by AILD.CONCLUSIONS:This PCR-based method for detecting clonal TCR rearrangements is a highly sensitive and specific technique for detecting T-cell clones in fresh and paraffin embedded tissues. The presence of a T-cell clone in all skin nodules of this patient, but not in the original lymph node affected by AILD, confirms previous findings that in some cases of AILD, clonal T-cell expansion may not be detectable until a later stage of the disease.

The site lies to the south of Aldgate High Street and to the east of the Minories. It was used for sand- or brickearth-quarrying in the 12th century, but for most of the medieval period was open land. The first major development took place in the late 16th and early 17th centuries, and was represented by substantial, though fragmentary, lengths of wall. Nevertheless, much of the ground probably still remained open, since it was used as a tip for refuse from a nearby slaughter-yard and for waste and crucibles from a factory producing Venetian-style glass.The most significant remains to be uncovered were parts of a row of terraced properties which were built in the 1670s and demolished in the mid 18th century. To the south of these lay a further building whose cellar was the only room surviving. All these structures are visible on contemporary maps; the archaeological evidence shows that they included both domestic units and workshops involved in clay tobacco-pipe manufacture and, possibly, metalworking. They were built wholly of brick, in a style which became common after the Great Fire. The associated finds seem to represent an accurate sample of the tools, personal possessions, household and kitchen utensils and structural fittings actually used in the buildings; these, together with the faunal remains, suggest that the occupants of the terraced properties enjoyed a relatively poor standard of living, but that the owners of the material found in the cellar were slightly more prosperous.

Computing at Dartmouth College has a reputation of being somehow different, though few people outside the institution know exactly how or why it is different. In a May 1974 Science magazine article, Arthur Luehrmann and John Nevison described the Dartmouth difference in terms of our policy of free-access to computing by everyone in the college community, a way to effect dramatic increases in the number of computer users with only modest costs. This free-access policy has important consequences for our User Services activities; it requires a special set of priorities but permits us to serve a large number of users with a small staff.