Advanced electrostatic ion thruster for space propulsion

The suitability of the baseline 30 cm thruster for future space missions was examined. Preliminary design concepts for several advanced thrusters were developed to assess the potential practical difficulties of a new design. Useful methodologies were produced for assessing both planetary and earth orbit missions. Payload performance as a function of propulsion system technology level and cost sensitivity to propulsion system technology level are among the topics assessed. A 50 cm diameter thruster designed to operate with a beam voltage of about 2400 V is suggested to satisfy most of the requirements of future space missions

The basic principles of migration health: Population mobility and gaps in disease prevalence

Currently, migrants and other mobile individuals, such as migrant workers and asylum seekers, are an expanding global population of growing social, demographic and political importance. Disparities often exist between a migrant population's place of origin and its destination, particularly with relation to health determinants. The effects of those disparities can be observed at both individual and population levels. Migration across health and disease disparities influences the epidemiology of certain diseases globally and in nations receiving migrants. While specific disease-based outcomes may vary between migrant group and location, general epidemiological principles may be applied to any situation where numbers of individuals move between differences in disease prevalence. Traditionally, migration health activities have been designed for national application and lack an integrated international perspective. Present and future health challenges related to migration may be more effectively addressed through collaborative global undertakings. This paper reviews the epidemiological relationships resulting from health disparities bridged by migration and describes the growing role of migration and population mobility in global disease epidemiology. The implications for national and international health policy and program planning are presented

An optical fibre dynamic instrumented palpation sensor for the characterisation of biological tissue

AbstractThe diagnosis of prostate cancer using invasive techniques (such as biopsy and blood tests for prostate-specific antigen) and non-invasive techniques (such as digital rectal examination and trans-rectal ultrasonography) may be enhanced by using an additional dynamic instrumented palpation approach to prostate tissue classification. A dynamically actuated membrane sensor/actuator has been developed that incorporates an optical fibre Fabry–Pérot interferometer to record the displacement of the membrane when it is pressed on to different tissue samples. The membrane sensor was tested on a silicon elastomer prostate model with enlarged and stiffer material on one side to simulate early stage prostate cancer. The interferometer measurement was found to have high dynamic range and accuracy, with a minimum displacement resolution of ±0.4μm over a 721μm measurement range. The dynamic response of the membrane sensor when applied to different tissue types changed depending on the stiffness of the tissue being measured. This demonstrates the feasibility of an optically tracked dynamic palpation technique for classifying tissue type based on the dynamic response of the sensor/actuator

The Practice of Immigration Health in Complex Emergency Situations - A Case Study of Kosovo from March to July 1999

The need to rapidly transport refugees, displaced as a result of evolving complex humanitarian emergencies creates challenges for those refugee-receiving nations that require formaI immigration medical screening of these populations. Balancing the need to expediently resettle the refugees with these legislative and regulatory medical requirements can be logistically and operationally difficult. During the 1999 Kosovo crisis, the Humanitarian Evacuation Programme from the Former Yugoslav Republic of Macedonia rapidly moved large numbers of Kosovar Albanian refugees to nations with existing formal immigration medical screening requirements. This paper describes the successful management and delivery of immigration health services during this complicated international event.La nécessité de transporter rapidement les réfugiés déplacés à cause d'urgences humanitaires complexes à évolution rapide représenteun défi pour les nations receveuses de réfugiés requérant un tamisage médical routinier de sa population immigrante. Des points de vue logistique et opérationnel, il peut s'avérer fort difficile pour ces états de concilier la nécessité de relocaliser rapidement les réfugiés avec les exigences de leurs lois et règlements en matière médicale et sanitaire. Lors de la crise du Kosovo de 1999, le Programme d'Évacuation Humanitaire de l'ancienne république yougoslave de Macédoine déplaça rapidement un grand nombre de réfugiés albanais kosovars vers des nations requérant formellement un tamisage médical de sa population immigrante. Cet article décrit la gestion et la distribution réussies de services de santé à l'immigration au cours de cet événement international complexe

Field Epidemiology Assessment for a Medical Evacuation Programme Related to the Crisis in Kosovo, 1999

In complex human emergency (CHE)-aid situations, the international community responds to provide assistance to reduce morbidity and mortality related to environmental and civil disruptions. The political and social situation in Kosovo, in combination with the military activity from 23 March to 09 June, 1999, created a crisis associated with mass movement of the population of Kosovo into neighbouring provinces and nations. This forced migration of people seeking protection increased demands for -water, food, shelter, and health care in the refugee areas. The United Nations High Commission for Refugees (UNHCR) estimated that 771,900 ethnic Albanians, and 30,700 Serbians, Croatians, and Montenegrins had been displaced from Kosovo during this time period, and that 439,500 of these people had arrived in Albania. Given the limited health-care resources in Albania to respond to the increasing demands for health care, a field epidemiological study was conducted by the International Organization for Migration (IOM) to assess the need for a medical evacuation program from Albania related to the crisis in Kosovo. Outcome measurements in this assessment were: 1) health-care capacity and health-care utilization rates in Albania before the crisis and by the refugees during the crisis; 2) the frequency of war-related injuries; 3) the frequency of medical evacuation; 4) nature of medical conditions of the patients being evacuated; and 5) destination for medical evacuation (internal or international) during the crisis. The results of the field assessment, which gathered health outcome data during the first eight weeks of the conflict (23 March 1999 to 25 May 1999), indicated that there was a need for a specifically designed medical evacuation programme in Albania. The study demonstrated that the implementation of a medical evacuation programme must be integrated with the national health care objectives. It also was found that the magnitude of an evacuation programme could be reduced markedly by strategic support of existing medical programmes in Albania (haemodialysis, trauma and orthopaedics, blood banking). Implementation of this strategy could permit containment of the majority of cases within Albania or to regional, health-care facilities. The results of such targeted support for specific services could result in a national programme for internal medical evacuation, with limited dependence upon the international movement of patient

Investigation of shock waves in explosive blasts using fibre optic pressure sensors

The published version of this article may be accessed at the link below. Copyright @ IOP Publishing, 2006.We describe miniature all-optical pressure sensors, fabricated by wafer etching techniques, less than 1 mm(2) in overall cross-section with rise times in the mu s regime and pressure ranges typically 900 kPa (9 bar). Their performance is suitable for experimental studies of the pressure-time history for test models exposed to shocks initiated by an explosive charge. The small size and fast response of the sensors promises higher quality data than has been previously available from conventional electrical sensors, with potential improvements to numerical models of blast effects. Results from blast tests are presented in which up to six sensors were multiplexed, embedded within test models in a range of orientations relative to the shock front.Support from the UK Engineering&Physical Sciences Research Council and Dstl Fort Halstead through the MoD Joint Grants Scheme are acknowledged. WN MacPherson is supported by an EPSRC Advanced Research Fellowship

Two-axis bend measurement with Bragg gratings in multicore optical fiber

We describe what is to our knowledge the first use of fiber Bragg gratings written into three separate cores of a multicore fiber for two-axis curvature measurement. The gratings act as independent, but isothermal, fiber strain gauges for which local curvature determines the difference in strain between cores, permitting temperature-independent bend measurement. (C) 2003 Optical Society of America