The rehabilitation of a Victorian clay brick railway viaduct

Larpool viaduct is a 13 span clay brick viaduct built between 1882 and 1884 to carry the Scarborough and Whitby railway across the picturesque Esk Valley in Whitby, North Yorkshire, England. The structure is of multi-ring clay brick arch construction supported on solid brickwork piers founded on mass concrete or concrete filled brickwork caissons. The railway was closed to rail traffic in 1965 but was re-opened to pedestrian and cycle traffic in 2000; it is now part of a regional sustainable transport network used mainly by tourists. Exposure to wind, driving rain and repeated freeze-thaw cycles has resulted in severe spalling of some of the brickwork, particularly that from the 30m high piers. This paper describes the original construction, the rehabilitation works including the historical context of the structure, site inspections prior to and during construction and a review of the rehabilitation works taking into account factors such as differential movement and the need to achieve a high standard of workmanship

A curve shortening flow rule for closed embedded plane curves with a prescribed rate of change in enclosed area

Motivated by a problem from fluid mechanics, we consider a generalization of the standard curve shortening flow problem for a closed embedded plane curve such that the area enclosed by the curve is forced to decrease at a prescribed rate. Using formal asymptotic and numerical techniques, we derive possible extinction shapes as the curve contracts to a point, dependent on the rate of decreasing area; we find there is a wider class of extinction shapes than for standard curve shortening, for which initially simple closed curves are always asymptotically circular. We also provide numerical evidence that self-intersection is possible for non-convex initial conditions, distinguishing between pinch-off and coalescence of the curve interior

Significant Miocene larger foraminifera from South Central Java

The Gunung Sewu area of South Central Java, Indonesia during Mid Miocene, Langhian-Serravallian (Tf1-Tf2), was deposited in a large area of warm, very shallow-marine water. Coralline algae and abundant larger benthic foraminifera dominate the carbonate lithologies. Larger benthic foraminifera from previously unstudied sections in South Central Java are described and figured. They have led to an understanding of sequence stratigraphic and facies relationship of Miocene carbonates in Indonesia. Thirteen larger foraminifera species are described and illustrated. A detailed biostratigraphical studies of The phylogeny Katacycloclypeus annulatus - K. martini and the gradual evolution from Austrotrillina asmariensis into A. howchini are recognised. Analysis of the larger benthic foraminifera has allowed accurate dating of the carbonate sections studied using the East Indian Letter Classification

An experimental investigation of retro-reinforced clay brick arches

This paper describes the laboratory testing of eight 2.95m span segmental profile clay brick arches. Seven of the arches were strengthened with longitudinal intrados (soffit) reinforcement; the eighth was left unreinforced as an experimental control. Three of the arches also contained reinforcement to resist inter-ring shear. The barrel of each arch consisted of 3 rings of brickwork laid in stretcher bond; the compressive strength of the mortar used in the arch construction varied from 1.7 to 6.2 MPa. In each case a full width line load was applied incrementally to the arch extrados at quarter span until collapse occurred. Surface crack development and the vertical deflection profile of each arch were recorded at each load increment. In all cases, the longitudinal reinforcement was found to delay the onset of cracking and to increase the load carrying capacity. As expected, premature failure by ring separation was found to occur in the arches constructed with the weakest mortar without inter-ring reinforcement. Radial dowels were found to be the most effective means of preventing ring separation. The effect of the longitudinal reinforcement was found to be greatest in the arches where measures were taken to prevent ring separation

First-principles study of H intercalation in rutile TiO2

Published versio

A novel technique to improve gain in transparent UWB antennas

A novel technique to improve the performance of AgHT-8 transparent polymer antennas is proposed in this paper. A spit-ring resonator is introduced on the radiating patch to enhance gain. The resonator basically concentrates the radiating energy to the central area of the patch thus improving gain. The designed antenna demonstrates good gain while maintaining the original transparency of the material. Such an antenna inscribed on the commercially available AgHT-8 sun shielding film material makes it a viable option for wireless applications like in-house base stations and applications requiring fast data rate transfers which can be mounted on windows and glass panels. © 2011 IEEE.Solutia Inc., St. Louis, Missouri, US

A non-thermal soldering technique to improve polymer based antenna performance

Copyright @ 2010 EuMCA non-thermal soldering technique using cold solder or electrically conductive epoxy for connecting SMA connectors to polymer based antennas is proposed in this paper. The proposed technique prevents damage to the polymer due to the solder iron heat and also the loss of efficiency through the use of indirect connections of the coaxial feed via copper pads glued to the antenna. The direct connection of the feed points via SMA connectors on to a transparent antenna designed on AgHT-8 material has been demonstrated. The method can also be applied to solder the coaxial feed points directly to the antenna instead of using copper pads which will introduce additional reflection losses. The technique involves the use of colder soldering instead of hot soldering so as to not damage the polymer based antenna as well as improve the efficiency of the antenna

Acoustic energy transmission in cast iron pipelines

In this paper we propose acoustic power transfer as a method for the remote powering of pipeline sensor nodes. A theoretical framework of acoustic power propagation in the ceramic transducers and the metal structures is drawn, based on the Mason equivalent circuit. The effect of mounting on the electrical response of piezoelectric transducers is studied experimentally. Using two identical transducer structures, power transmission of 0.33 mW through a 1 m long, 118 mm diameter cast iron pipe, with 8 mm wall thickness is demonstrated, at 1 V received voltage amplitude. A near-linear relationship between input and output voltage is observed. These results show that it is possible to deliver significant power to sensor nodes through acoustic waves in solid structures. The proposed method may enable the implementation of acoustic - powered wireless sensor nodes for structural and operation monitoring of pipeline infrastructure

The rehabilitation of short span masonry arch highway bridges using near-surface reinforcement

Near-surface reinforcement has been developed as a minimum intervention, minimum disruption repair or strengthening technique for masonry arch bridges and similar structures. It involves installing small diameter stainless steel reinforcing bars, typically 6mm to 12mm in diameter, into pre-cut grooves or pre-drilled holes in the near-surface zones of the bridge that are likely to be subject to tensile stress. The principal aims of adding reinforcement are to improve flexural crack control, increase flexural and shear strength and to increase robustness and ductility. Typically the reinforcement is installed in the readily accessible surfaces, i.e. the intrados (or soffit) of the arch barrel and the exposed faces of the piers, abutments, spandrels, parapets and wingwalls. This paper summarises the results of a series of tests carried out on 2.95m span clay brick arches in the laboratory. The results of the research were used when designing the strengthening works for a single span arch bridge constructed in the late 18th century to span the Kennet and Avon Canal at Hungerford in Southern England. An innovative feature of this project, which is also briefly described in the paper, is that the longitudinal steel reinforcement was installed in holes that were pre-drilled into the soffit of the arch barrel to follow the line of the arch using a directed drilling technique. The strengthening scheme was given an Historic Bridge and Infrastructure Award by the Institution of Civil Engineers

A novel technique and soldering method to improve performance of transparent polymer antennas

This article is archived here with permission from IEEE - Copyright @ 2010 IEEEA novel technique and a non-thermal soldering method to improve the performance of AgHT-8 transparent polymer antennas are proposed in this paper. The proposed technique involves the removal of the coating layer at areas on the CPW ground and feed line where the connectors of the coaxial feed or legs of the SMA connectors will be attached, and applying a coat of silver paint on the exposed areas before cold soldering the coaxial connections or SMA connector legs. The non-thermal or cold soldering using electrically conductive paste enables direct soldering of the co-axial feed points or connector legs which cannot otherwise be done with hot or thermal soldering. This type of connection greatly enhances the performance of the AgHT-8 polymer antennas compared to coaxial feed point connections through hot soldered copper pads glued to the surface of the polymer coating. The proposed technique also gives a stronger connection bond than directly cold soldering the feed points or connectors to the smooth surface of the AgHT-8 material. Furthermore, the copper pad connection technique also introduces additional losses contributed by the adhesive properties of the glue used. This proposed novel technique and soldering method may be extended to enhance antenna performance made from other similar transparent conductive polymers like IT