Temperature Characterisation of LPG Sensors for Monitoring Deterioration in Reinforced Concrete

Summary Optical fibre technology is increasingly being used to monitor stresses and strains in structural members, thus leading to the development of intelligent structures. A research project is currently underway to further expand on the development of optical strain sensors by developing sensors for deterioration monitoring in reinforced concrete. A prototype sensor based on long period fibre gratings (LPGs) is being produced that will detect chemical changes within the concrete and on the steel reinforcement surface, thus indicating initiation of corrosion. Novel coatings will be adhered to the surface of the LPG which react with chemical changes and corrosion inducing substances at the steel/concrete interface thus changing the optical properties of the LPG. The paper presents the results of preliminary tests to characterise the LPG for temperature variations. The purpose of the tests is twofold: firstly, to determine if the LPG is sensitive to a varying external medium and secondly, to compensate for the effects of temperature in the working sensor. It is shown that the temperature coefficients for the LPGs considered do not vary too much if water is used as the external medium instead of air. It is also shown that the temperature response of LPGs can be both positive and negative. Low order resonance bands are shown to be as sensitive to temperature changes as high order bands. Finally, the importance of keeping LPGs taut when testing is emphasised as results are affected by bend-induced spectral changes

Stabilization of Expansive Soils Using Flyash and Murrum

ABSTRACT: Construction projects like water reservoirs highways, railways, reclamation etc. requires earth material in very large quantity. Due to lots of power projects lots of ash is produced. This by-product is really a difficult and expensive. Also in urban areas, borrow earth is not easily available which has to be brought from a long distance. Most of the time, large areas are covered with highly plastic and expansive soil, which is not suitable for construction purpose. Extensive laboratory and field trials have been carried out by various researchers and have shown promising results for application of such expansive soil after stabilization with additives like cement, sand, silt, lime, fly ash, murrum, etc. As fly ash & murrum is freely available, for projects in the in nearby vicinity, it can be used for stabilization of expansive soils for various uses. The present paper describes a study carried out to check the improvements in the properties of expansive soil with fly ash, murrum in varying percentages. The laboratory tests have been carried out and results are reported in this pape

COMPETENCES MANUAL FOR “ENVIRONMENTAL AQUACULTURE / FISHERY”

This Manual provides an inventory of specific competencies necessary for effective job performance in Fishery sector and is based on a survey among East-Asian employers and HE-teachers. It was developed as a resource for students, teachers and employees of public and private enterprises.Das Handbuch enthält eine Bestandsaufnahme der spezifischen Kompetenzen, die für eine effektive Arbeitsleistung im Fischereisektor erforderlich sind und auf einer Umfrage unter ostasiatischen Arbeitgebern und Hochschullehrern basiert. Dieses Kompetenzhandbuch wurde als Ressource für Studierende, Lehrer und Mitarbeiter öffentlicher und privater Unternehmen entwickelt