This paper provides an overview of the different types of fiber optic sensors (FOS) that can be used with composite materials and also their compatibility with and suitability for embedding inside a ...composite material. An overview of the different types of FOS used for strain/temperature sensing in composite materials is presented. Recent trends, and future challenges for FOS technology for condition monitoring in smart composite materials are also discussed. This comprehensive review provides essential information for the smart materials industry in selecting of appropriate types of FOS in accordance with end-user requirements.
We have investigated the influence of multimode fiber core (MMFC) diameters and lengths on the sensitivity of an SMS fiber based refractometer. We show that the MMFC diameter has significant ...influence on the refractive index (RI) sensitivity but the length does not. A refractometer with a lower MMFC diameter has a higher sensitivity. Experimental investigations achieved a maximum sensitivity of 1815 nm/ RIU (refractive index unit) for a refractive index range from 1.342 to 1.437 for a refractometer with a core diameter of 80 μm. The experimental results fit well with the numerical simulation results.
Workplace aggression remains an important source of distress among nurses and midwives and has negative effects on staff health, patient care and organisations’ reputation and fiscal health.
To ...report on the nature and extent of workplace aggression, including bullying experienced by nurses and midwives in Victoria, Australia.
A descriptive study design was chosen.
The Nurses Board of Victoria posted 5000 surveys to the randomly selected registered nurses and midwives in Victoria, Australia, in 2010. The participants were asked about their experiences of violence (from clients) and bullying (from colleagues) within their most recent four working weeks. In addition, the study investigated staff actions following incidents, staff training and safety at work, and what staff believe contribute to incidents. Data analysis involved descriptive statistics, including frequencies and percentages. Chi square tests and P value were used to assess differences in categorical data.
1495 returned questionnaires were included in the study (30% response rate). Over half of the participants (52%) experienced some form of workplace aggression. Thirty-six percent experienced violence mostly from patients or their visitors/relatives and 32% experienced bullying mostly from colleagues or from their managers/supervisors. Significant differences were found between those who experienced aggression from patients and those who were bullied in respect to handling of incidents; factors thought to contribute to incidents; and organisations’ handling of incidents.
The study suggests that staff are less worried by patient initiated aggression compared to bullying from colleagues. For all types of aggression, respondents clearly wanted better/more realistic training, as well as enforcement of policies and support when incidents arise.
We report the effect of coating thickness on the sensitivity of a relative humidity (RH) sensor based on an Agarose coated photonic crystal fiber interferometer for the first time. An experimental ...method is demonstrated to select an optimum coating thickness to achieve the highest sensitivity for a given RH sensing range. It is shown that the Refractive Index (RI) of the coating experienced by the mode interacting with the coating depends on the thickness of the coating. It is observed that the spectral shift of the interferometer depends on both the bulk RI change and the thickness change of the Agarose coating with respect to an RH change. The RH sensitivity of the sensor has a significant dependence on the thickness of the coating and the sensor with highest sensitivity shows a linear response for RH change in the range of 40-90% RH with a humidity resolution of 0.07%RH and a fast response time of 75 ms for an RH change from 50% to 90%.
In this article, a novel long-period fiber grating (LPFG) sensor based on a core-cladding misalignment structure is described. The LPFG consists of multiple short-length singlemode fiber (SMF) ...segments joined with core-cladding misalignment splicing. Due to the refractive index (RI) difference between the core and the cladding, periodic RI modulation along fiber axis is achieved. The resonance wavelength responses of the core-cladding misalignment structure based LPFG to RI, strain and temperature are investigated experimentally, and a maximum RI sensitivity of 992.8 nm/RIU, a strain sensitivity of −7.4 pm/μϵ, and a temperature sensitivity of −31 pm/°C are obtained, respectively. Such a core-cladding misalignment structure provides a low-cost fabrication route for LPFGs while offering high sensitivities, which has potential applications for accurate measurement and sensing in industrial and harsh environments.
In recent years, tapered optical fibers (TOFs) have attracted increasing interest and developed into a range of devices used in many practical applications ranging from optical communication, sensing ...to optical manipulation and high-Q resonators. Compared with conventional optical fibers, TOFs possess a range of unique features, such as large evanescent field, strong optical confinement, mechanical flexibility and compactness. In this review, we critically summarize the multimode interference in TOFs and some of its applications with a focus on our research project undertaken at the Optoelectronics Research Centre of the University of Southampton in the United Kingdom.
This paper proposes a novel magnetic field sensor based on a microfiber coupler (MFC) combined with a magnetic fluid (MF) in a Sagnac loop formed from a polarization maintaining fiber (PMF). Thanks ...to the small (~2.6 μm) waist diameter of the MFC, the resulting interference is strongly influenced by the presence of the MF and this leads to the desirable high sensitivity of the structure to the applied magnetic field. The maximum magnetic field sensitivities of -100 pm/mT and -488 pm/mT have been experimentally demonstrated with the PMF lengths of 75 cm and 20 cm respectively in the range of magnetic field strengths from 0 to 200 mT. The dependence of the magnetic field orientation on the performance of the proposed sensor was also examined. The proposed magnetic field sensor is advantageous for applications requiring higher sensitivity over a wide magnetic field range.
Aim. This paper reports a study of workplace aggression among nurses in Tasmania, Australia.
Background. There is international concern about a perceived rise in occupational violence as a major ...worldwide public health problem, with associated financial costs. There is reason to suspect that aggression towards nurses is increasing. For example, increased illicit drug use puts nurses at the sharp end in managing patients admitted with drug‐related problems. Such people are often resistant to healthcare intervention, and often have associated disorders, including mental illness. Despite this increased awareness, comprehensive data on occupational violence in nursing are not available.
Method. A specially designed questionnaire was sent to all nurses registered with the Nursing Board of Tasmania (n = 6326) in November/December 2002, with 2407 usable questionnaires returned. The response rate was 38%.
Findings. A majority of respondents (63·5%) had experienced some form of aggression (verbal or physical abuse) in the four working weeks immediately prior to the survey. Patients/clients or their visitors were identified as the main perpetrators, followed by medical and nursing colleagues. Abuse influenced nurses’ distress, their desire to stay in nursing, their productivity and the potential to make errors, yet they were reluctant to make their complaints ‘official’. As well as reporting high levels of verbal and physical abuse, nurses were distressed because they could not provide the appropriate care to meet patients’ needs. Few working environments were free of aggression.
Conclusion. Future research should try to determine the specific factors, including staff characteristics and environment, associated with the high levels of aggression reported in ‘hot spots’ where, on the basis of the present results, many staff experience high levels of verbal and physical abuse. Unless managers take steps to improve the situation, attrition from the profession for this reason will continue.
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