Smart slope monitoring through the use of fibre optic sensors

Abstract: This study demonstrates the use of fibre optic instrumentation such as an Optical Time-Domain Reflectometer as well as Fibre Bragg Grating sensors on a small-scale physical 1-g model to monitor potential slope movement. The scope is to improve current knowledge in the field of slope monitoring through the im- plementation of optic fibre sensors. Single-mode and multi-mode hetero-core optic fibre displacement sensors were created and directly embedded into layers of coarse-grained soil. By inducing critical slope conditions in the small-scale model through the course of several experiments we were able to identify localised failure zones and quantify signal attenuation. Using a calibrated source, it was possible to indirectly estimate microstrain and investigate spatial resolution of the sensing cable. Laboratory testing of the sensors and the sensing system allowed for further development of sensor integration techniques

A dual wavelength erbium doped fibre ring laser employing 3dB coupler and FBGs in preparation for dispersion measurement

Abstract: A simple dual -wavelength c-band laser source with the aid of Fibre Bragg gratings (FBG) with an optical SNR of up to 70dB is demonstrated. The laser includes a 3,2m Erbium doped fibre with 11,38dB/m absorption in a ring resonating cavity with optical couplers. The ring cavity had two FBGs centred at 1555.12nm and 1560.32nm attached by a 3dB coupler. A 1m long sagnac loop with 70:30 coupling was used to stabilise the dual wavelength emission to about 2dB. The multiwavelength and narrow spectral width of 0.183nm and 0.195nm of the laser can be used for dispersion measurement in WDM communication links which consist of more than one wavelength. The laser was characterised for dual output power response and power stability. The paper present a characterisation of an Erbium doped fibre (EDF) ring laser. The laser is cost effective and dynamic in selecting preferred components for optimal performance in terms of power and wavelength stability, wavelength selectivity and narrow spectral width. EDF lasers are commercial available and already showing great promise in terms of the formidability and compatibility with current industrial requirements

Factors influencing a mother's choice of feeding after discharge of her baby from a neonatal unit

Objective. To assess feeding methods chosen by mothers of babies who spent time in a neonatal unit.  Factors influencing this decision were investigated.Design. Descriptive study.Methods. Mothers were interviewed on the day they took their babies home. Basic demographic data on mother and baby were collected from the hospital records.Setting. The neonatal unit, Pelonomi Hospital, Bloemfontein from May 1996 to May 1998.Subjects. Eighty-one mothers of babies admitted to the neonatal unit.Outcome measures. At discharge 60% of mothers intended to breast-feed their babies exclusively the  next day. The mother's decision to breasHeed her baby at home was significantly associated with her decision before delivery (P = 0.0050). Otherfactors positively associated with the decision to breast-feed exclusively at home were a significantly higher birth weight of the baby (P < 0.0008) and gestational age of the baby (P < 0.0005). The only hospital practice positively associated with this decision was the frequency with which mothers saw their babies during their stay in the unit (P = 0.0153). Mothers' knowledge of how to increase breast-milk supply was very poor.Conclusions. Infants with a lower weight and gestational age, who stayed in the unit longer, were less  likely to be breast-fed after discharge from the neonatal unit. The mothers' experience in the unit did not seem to alter their choice of feeding method decided upon before delivery. This suggests that efforts to promote breast-feeding in the neonatal unit were either ineffectual or inadequate. In order to remedy this situation it is necessary to keep the motherinfant pair together (lodger mothers) and to promote  breastfeeding before and after delivery. It would also be necessary to train staff in the management of lactation problems

Functional Evaluation in Respiratory Disorders

Geneeskunde en GesondheidswetenskappeInterne GeneeskundePlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

Towards a cyberterrorism life-cycle (CLC) model

Cyberterrorism has emerged as a new threat in the Information and Communication Technology (ICT) landscape. The ease of use, affordability, remote capabilities and access to critical targets makes cyberterrorism a potential threat to cause wide-scale damage. Cyberterrorism is often incorrectly perceived as encompassing all cybercrimes. However, cyberterrorism differs from cybercrime in various ways including motivation, attack goals, techniques and effects. Motivations for cyberterrorism, which is similar to terrorism in general, stem from religious, social and political views. Cyberterrorists generally would seek to have high impact in order to gain publicity for their cause, whereas cybercriminals often prefer to have their acts undetected in order to hide their financial theft, fraud or espionage. Therefore, there are various factors that drive the development of a cyberterrorist. This paper proposes a model for the development of cyberterrorism in order to show the various influential forces. The Cyberterrorism Life-Cycle (CLC) model presented in this paper is composed of five phases: Prepare, Acquaint, Choose, Execute, and Deter (PACED). In addition the paper looks at various factors, including social, practices, objectives, targets and countermeasures, which are mapped onto the PACED phases in order to show the interaction and dynamic nature during the life-cycle development