Heart-rate pulse-shift detector

Detector circuit accurately separates and counts phase-shift pulses over wide range of basic pulse-rate frequency, and also provides reasonable representation of full repetitive EKG waveform. Single telemeter implanted in small animal monitors not only body temperature but also animal movement and heart rate

Buckling and vibration of periodic lattice structures

Lattice booms and platforms composed of flexible members or large diameter rings which may be stiffened by cables in order to support membrane-like antennas or reflector surfaces are the main components of some large space structures. The nature of these structures, repetitive geometry with few different members, makes possible relatively simple solutions for buckling and vibration of a certain class of these structures. Each member is represented by a stiffness matrix derived from the exact solution of the beam column equation. This transcendental matrix gives the current member stiffness at any end load or frequency. Using conventional finite element techniques, equilibrium equations can be written involving displacements and rotations of a typical node and its neighbors. The assumptions of a simple trigonometric mode shape is found to satisfy these equations exactly; thus the entire problem is governed by just one 6 x 6 matrix equation involving the amplitude of the displacement and rotation mode shapes. The boundary conditions implied by this solution are simple supported ends for the column type configurations

Inelastic tunnel diodes

Power is extracted from plasmons, photons, or other guided electromagnetic waves at infrared to midultraviolet frequencies by inelastic tunneling in metal-insulator-semiconductor-metal diodes. Inelastic tunneling produces power by absorbing plasmons to pump electrons to higher potential. Specifically, an electron from a semiconductor layer absorbs a plasmon and simultaneously tunnels across an insulator into metal layer which is at higher potential. The diode voltage determines the fraction of energy extracted from the plasmons; any excess is lost to heat

Solar energy converter using surface plasma waves

Sunlight is dispersed over a diffraction grating formed on the surface of a conducting film on a substrate. The angular dispersion controls the effective grating period so that a matching spectrum of surface plasmons is excited for parallel processing on the conducting film. The resulting surface plasmons carry energy to an array of inelastic tunnel diodes. This solar energy converter does not require different materials for each frequency band, and sunlight is directly converted to electricity in an efficient manner by extracting more energy from the more energetic photons

The effect of dietary cadmium on kidney function in cats : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science at Massey University, Palmerston North, New Zealand

Due to the requirement for meat in feline diets, this study aimed to investigate the potential effects on kidney function in cats of cadmium accumulation in meat products due to pasture management practices. Cadmium may be a causal factor in feline Chronic Kidney Disease (CKD). Twenty-seven domestic short hair cats were randomly selected from the colony population of the Feline Nutrition Unit of Massey University and assigned to three experimental groups (n=9), which were balanced for age and sex. Each group received one of the three experimental diets designed to represent the full range of potential cadmium concentrations that cats may be exposed to on wet diets in New Zealand. Diets were fed ad libitum for a 6-month period. Kidney function was examined at baseline and after 3 and 6 months by measuring glomerular filtration rate (GFR) using iohexol clearance analysed by high performance liquid chromatography (HPLC). Blood and urine analyses were also conducted on a monthly basis. While GFR fluctuated over the study period no significant differences were found either between groups at the end, or within each group when compared at the beginning and end of the study. Although overall no evidence of CKD was observed, an unexplained trend of weight loss was observed in females receiving the two diets containing the highest cadmium levels, which may simply have reflected reduced dietary palatability. The results of the study showed no detectable effects of feeding the three diets for 6 months; however, an extended trial period may be required to fully investigate the longer term effects of cadmium levels and other dietary factors on the development of CKD. In particular, more work is needed to explore the potential for genetic and/or functional differences in mechanisms which are involved in the transport, and/or deposition of cadmium, or are protective against cadmium toxicity in cats and to further define normal parameters and standard approaches in measuring GFR in cats

Sun-synchronous highly elliptical orbits using low-thrust propulsion

Due to restrictions within the current architecture of the global observing system (GOS), space-based remote sensing of Earth suffers from an acute data-deficit over the critical polar-regions. Currently, observation of high-latitude regions is conducted using composite images from spacecraft in geostationary (GEO) and low-Earth orbits (LEOs) [1]. However, the oblique viewing geometry from GEO-based systems to latitudes above around 55 deg [2] and the insufficient temporal resolution of spacecraft in LEO means there is currently no source of continuous imagery for polar-regions obtained with a data refresh rate of less than 15 minutes, as is typically available elsewhere for meteorological observations

Extension of earth orbits using low-thrust propulsion

The primary motivation for the utilization of space for environmental science, and in-particular Earth Observation, is the unique vantage point which a spacecraft can provide. For example, a spacecraft can provide a global dataset with a much higher temporal resolution than any other platform. Earth Observation spacecraft are increasingly focused on a single primary application, typically conducted from a small set of classical orbits which limits the range of vantage points and hence the type of observations which can be made. The next generation of innovative Earth Observation spacecraft may however only be enabled through new orbit options not considered in the past. The objective of the study was therefore to enlarge the set of potential Earth orbits by considering the use of low-thrust propulsion to extend the conventional Molniya orbit. These new orbits will use existing, or near-term low-thrust propulsion technology to enable new Earth Observation science and offer a radically new set of tools for mission design. Continuous low-thrust propulsion was applied in the radial, transverse and normal directions to vary the critical inclination of the Molniya orbit, while maintaining the zero change in argument of perigee condition. As such the inclination can be freely altered from the expected critical inclination of 63.4 deg, to, for example 90 deg, creating a Polar-Molniya orbit. Analytical expressions were developed which were then validated using a numerical model, to show that not only was the argument of perigee unchanged but all other orbital elements were also unaffected by the applied low-thrust. It was shown that thrusting in the transverse direction allowed the spacecraft to achieve any inclination with the lowest thrust magnitude in any single direction; this value was however found to be further reduced by combining both radial and transverse thrust. Real-time continuous observation of the Arctic Circle is then enabled using current electric propulsion technology, with fewer spacecraft than the traditional Sun-synchronous polar orbit, and at reduced range than a 'pole-sitter'. Applications of such an orbit would include more accurate Arctic weather predictions and severe weather event warnings for this region

Case study: design, operation and water quality management of a combined wet and dry pond system

Pond structures as cost-effective water treatment, storage and “source control” drainage techniques can be applied in order to reduce wastewater treatment costs, produce water for subsequent recycling and reduce the risk of downstream flooding. However, there is a need for detailed design, operation and maintenance data. The purpose of this study was to optimise design and operation guidelines, and to assess the water treatment potential of stormwater pond systems. Performance data (15 months) for a stormwater pond pilot plant were collected. The system is based on a combined silt trap, attenuation wet pond and dry pond system applied for drainage of roof water run-off from a single domestic property. United Kingdom Building Research Establishment and Construction Industry Research and Information Association, and German Association for Water, Wastewater and Waste design guidelines were tested. These design guidelines were insufficient because they do not consider local hydrological and soil conditions. The infiltration function for the dry pond is logarithmic and depends on the season. Furthermore, biochemical and physical algal control techniques were successfully applied, and passive water treatment of rainwater run-off with a wet pond was found to be sufficient. However, seasonal and diurnal variations of biochemical oxygen demand, dissolved oxygen and pH were recorded. Finally, capital and labour costs for small ponds are high

Reflecting on the technical development of the Mapping Sculpture project

This paper explains, evaluates and reflects on the technical challenges and opportunities that underpin both the Mapping Sculpture project and its mobile interface. It provides insights into the development process as an integral component of the research methodology, and highlights the importance of meaningful collaboration between researchers and software developers. Just as the project questions the conventional notion of the lone sculpture practitioner, so the technical development needed to mirror the complex web of connections between people, places, objects, organizations and events through enabling large-scale, distributed and collaborative research. Enabling access to these rich resources on mobile devices was a further innovative and challenging development, but one that opens up the possibility for fresh modes of access and development of new audiences. The success of this technical development offers a model for representing complex relationships hidden in multiple sources, enabling innovative research and enhancing access