NASA Space applications of high-temperature superconductors

The application of superconducting technology in space has been limited by the requirement of cooling to near liquid helium temperatures. The only means of obtaining these temperatures has been with cryogenic fluids which severely limit mission lifetime. The development of materials with superconducting transition temperatures above 77 K has made superconducting technology more attractive and feasible for employment in aerospace systems. Here, potential applications of high temperature superconducting technology in cryocoolers, remote sensing, communications, and power systems are discussed

Emerging applications of high temperature superconductors for space communications

Proposed space missions require longevity of communications system components, high input power levels, and high speed digital logic devices. The complexity of these missions calls for a high data bandwidth capacity. Incorporation of high temperature superconducting (HTS) thin films into some of these communications system components may provide a means of meeting these requirements. Space applications of superconducting technology has previously been limited by the requirement of cooling to near liquid helium temperatures. Development of HTS materials with transition temperatures above 77 K along with the natural cooling ability of space suggest that space applications may lead the way in the applications of high temperature superconductivity. In order for HTS materials to be incorporated into microwave and millimeter wave devices, the material properties such as electrical conductivity, current density, surface resistivity and others as a function of temperature and frequency must be well characterized and understood. The millimeter wave conductivity and surface resistivity were well characterized, and at 77 K are better than copper. Basic microwave circuits such as ring resonators were used to determine transmission line losses. Higher Q values than those of gold resonator circuits were observed below the transition temperature. Several key HTS circuits including filters, oscillators, phase shifters and phased array antenna feeds are feasible in the near future. For technology to improve further, good quality, large area films must be reproducibly grown on low dielectric constant, low loss microwave substrates

The physical and mental health of acute psychiatric ward staff, and its relationship to experience of physical violence

To evaluate and describe the physical and mental health of staff on acute psychiatric wards and examine whether violence exposure is linked with health status. We undertook a cross-sectional survey with 564 nursing staff and healthcare assistants from 31 psychiatric wards in nine NHS Trusts using the SF-36, a reliable and valid measure of health status and compared summary scores with national normative data. Additional violence exposure data were collated simultaneously and also compared with health status. The physical health of staff was worse, and their mental health was better than the general population. Physical health data were skewed and showed a small number of staff in relatively poor health while the majority were above average. Better physical health was associated with less time in the current post, a higher pay grade, and less exposure to mild physical violence in the past year. Better mental health was associated with being older and from an ethnic minority background. Violence exposure influenced physical health but not mental health when possible confounders were considered. Mental health was strongly influenced by ethnicity, and further research might highlight the impact on own-group ethnic density on the quality of care. The impact of staff whom are physically unwell or impaired in the workplace needs to be considered as the quality of care may be compromised despite this being an example of inclusiveness, equal opportunities employment, and positive staff motivation

Analytical growth equations and their Genstat 5 equivalents

Two ways of representing some of the existing growth functions, (the exponential, the monomolecular or Mitscherlich, the logistic or autocatalytic, the Gompertz, and the Richards equations) are compared. In the first, growth is expressed in the parameters mass at time zero W0, mass at time infinity Wf, and a measure for the relative growth rate k. In the second, different parameters are used because of robust parameter optimization (e.g., by the statistical software package Genstat). The relationships between these fitted parameters and the parameters W0, Wf and k are demonstrated. The properties of these models, such as physical meaning of the parameters, properties at the point of inflection (if it exists), and the growth rate at a limit W -> 0, are examined. The second order exponential polynomial was rewritten in such a way that use was made of a proportionality constant, equal to the relative growth rate at the point of inflection. Application of the growth models is demonstrated using data for lettuce grown in a nutrient film system. Finally, it is shown that, except for the exponential polynomial, all growth equations originate from one single equation

High temperature superconducting thin film microwave circuits: Fabrication, characterization, and applications

Epitaxial YBa2Cu3O7 films were grown on several microwave substrates. Surface resistance and penetration depth measurements were performed to determine the quality of these films. Here the properties of these films on key microwave substrates are described. The fabrication and characterization of a microwave ring resonator circuit to determine transmission line losses are presented. Lower losses than those observed in gold resonator circuits were observed at temperatures lower than critical transition temperature. Based on these results, potential applications of microwave superconducting circuits such as filters, resonators, oscillators, phase shifters, and antenna elements in space communication systems are identified

Factors Affecting Capture Rates of Insect Taxa by Retail Electrocutors and Eliminators in Northern Lower Michigan

We compare the abundance and types of insects captured at several locations, with and without a chemical attractant and in varying weather conditions using two different devices advertised to kill biting insects. Using both an insect electrocutor that uses ultraviolet light as an attractant, with and without octenol as an added attractant, and an insect eliminator that uses carbon dioxide, heat and octenol as attractants, more non-biting than biting insects were captured. Numerous harmless and beneficial insects were killed with electrocutors. Although eliminators were more target-specific, they captured fewer insects overall compared to electrocutors. The numbers and types of insects captured also varied by location and temperature conditions. More insects were killed by electrocutors located next to a lake compared to those located in an inland forested area and more were killed at lower compared to higher heights above the ground. More insects were also killed by electrocutors on warmer than on cooler nights. More non-biting insects were killed with electrocutors baited with octenol than without octenol

Understanding and applying compression therapy

Atkin L, Shirlow

The relationship between public and private bicycle use: the case of Seville

Despite the success achieved by Public Bicycle Sharing Systems (PBSS) across the world, several researchers provide evidence on their limitations and constraints in a medium-long term, and bicycle ownership may be considered as a complementary tool to promote a 'bicycle-culture'. This paper aims to cover the gap about the interaction between both systems (public bicycle / private bicycle) and which are the key aspects to explain the bicycle-buying decision. After a fieldwork based on surveys conducted in Seville (Spain), one of the cities currently acknowledged worldwide for its successful policy of promoting cycling, we apply a Discrete Choice Model. Our findings show that among the socio-demographic factors that favor the move from the PBSS to the private bicycle are: having a higher level of education, being more progressive ideologically-speaking, and being a resident of the city itself; while age and gender do not appear to be conclusive. Experienced users, for whom the bicycle is a part of his /her healthy lifestyle, state a greater willingness to buy a bicycle. And the main obstacles to make the jump from the PBSS to the private bicycle, and that any action plan to support private bicycle usage should take into account, are: the lack of proper parking at the origin/destination, and fear of theft

Analog VLSI-Based Modeling of the Primate Oculomotor System

One way to understand a neurobiological system is by building a simulacrum that replicates its behavior in real time using similar constraints. Analog very large-scale integrated (VLSI) electronic circuit technology provides such an enabling technology. We here describe a neuromorphic system that is part of a long-term effort to understand the primate oculomotor system. It requires both fast sensory processing and fast motor control to interact with the world. A one-dimensional hardware model of the primate eye has been built that simulates the physical dynamics of the biological system. It is driven by two different analog VLSI chips, one mimicking cortical visual processing for target selection and tracking and another modeling brain stem circuits that drive the eye muscles. Our oculomotor plant demonstrates both smooth pursuit movements, driven by a retinal velocity error signal, and saccadic eye movements, controlled by retinal position error, and can reproduce several behavioral, stimulation, lesion, and adaptation experiments performed on primates