Hybrid image/ray-shooting UHF radio propagation predictor for populated indoor environments

A novel model for indoor wireless communication, based on a dual image and ray-shooting approach, is presented. The model, capable of improved site-specific indoor propagation prediction, considers multiple human bodies moving within the environment. In a modern office at 2.45GHz, the combined effect of pedestrian traffic and a moving receiver causes rapid temporal fading of up to 30dB.

RF performance of a 418-MHz radio telemeter packaged for human vaginal placement

The electrical and communication performance of a 0.8-mu W UHF temperature telemeter designed for human vaginal placement is discussed; a solenoidal loop antenna was used, occupying a volume of 0.1 cm(3). In situ, measured power absorption was between 19-25 dB, resulting in an effective operating range of 10 m. Capacitive loading lowered the antenna's resonant frequency by 1.4% and there was a significant polarization change in the radiated output.

Vaginal temperature sensing using UHF radio telemetry

User induced errors are common when women repetitively employ conventional probe type thermometers to chart their basal body temperatures in an effort to indicate ovulation. An alternative technique employing a two-part telemetric thermometer is proposed, with low-power, SAWR-controlled UHF radio as the transmission medium. Worn overnight in the vagina, the 1 mu W erp telemetry transmitter sends pulse modulated data continuously to a microcontroller in a nearby receiver; a real time clock enables programmable sampling and storage of the subject's temperature to 0.1 degrees C resolution. Initial clinical results indicate an enhanced performance compared to oral and axillary temperature trends taken by a mercury-in-glass thermometer. Polar plots of both the isolated and body-worn telemetry transmitte are presented; body indced attenuations of up to 30 dB were measured.

DENSE GAS IN NEARBY GALAXIES .6. A LARGE C-12/C-13 RATIO IN A NUCLEAR STARBURST ENVIRONMENT

Toward the starburst nucleus of NGC 253, C-12/C-13 line intensity ratios from six carbon bearing molecules (CO, CN, CS, HCN, HCO+, and HNC) are used to confine the possible range of carbon and oxygen isotope ratios. A detailed analysis yields C-12/C-13 approximately 40 and O-16/O-18 approximately 200. Also reported are first detections of (CS)-C-13 and of the 0(0) - 1(-1) E line of methanol (CH3OH) in an extragalactic source.

Facile in situ synthesis of nanofluids based on ionic liquids and copper oxide clusters and nanoparticles

Two stable nanofluids comprising of mixed valent copper(_I,_II) oxide clusters (<1 nm) suspended in 1-butyl-3-methylimidazolium acetate, [C(₄)mim][OAc], and copper(_II) oxide nanoparticles (<50 nm) suspended in trioctyl(dodecyl) phosphonium acetate, [P-₈₈₈₁₂][OAc], were synthesised in a facile one-pot reaction from solutions of copper(_II) acetate hydrate in the corresponding ionic liquids. Formation of the nanostructures was studied using ¹³C NMR spectroscopy and differential scanning calorimetry (DSC). From a solution of Cu(OAc)₂ in 1-ethyl-3-methylimidazolium acetate, [C₂mim][OAc], crystals were obtained that revealed the structure of [C₂mim][Cu₃(OAc)₅(OH)₂(H₂O)]center dot H₂O, indicating the formation of copper hydroxo-clusters in the course of the reaction. Synthesised nanostructures were studied using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Physical properties of the prepared IL-nanofluids were examined using IR and UV-VIS spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and densitometry. 

Transmission characteristics of a vaginally-worn UHF radio telemeter

A vaginally-worn temperature telemeter may be used by women to chart their basal body temperature for ovulation detection. The telemeter uses a temperature to pulse width converter to key a Colpitts oscillator which is controlled in frequency by a 418 MHz SAW resonator. The circuit’s tank inductor acts as a compact, multi-turn loop antenna with a radiated power in isolation of around 1 uW. The transmission characteristics of the system are affected by the proximity of the human body, which acts as an electrically-large lossy dielectric. The RF link-budget must allow for the reduction in total emitted power, directional body-induced fading, and polarization effects. The polar power patterns of the telemeter were measured for both isolated and in-situ cases, using horizontal and vertical polarization. The power patterns were numerically integrated to determine relative emitted power, and a reference dipole used to determine the emitted power for the isolated device. In isolation the telemeter radiation is vertically polarized and isotropic in nature. With the telemeter in-situ, total body absorption was found to be over 20 dB, with directional fades of up to 40 dB; there was extensive cross-polarization, with up to 60% of radiated power horizontally polarized. With limited radiated power and directional fading, the operating range for the telemeter is limited to single room operation (less than 10m). The majority of RF radiation is absorbed by the body, but the radiation hazard is negligible due to the low power level of the device. The high level of cross-polarization suggests that either horizontal or vertically polarized base-station antennas may be used.

Low-power radio telemetry: the potential for remote patient monitoring

Radio-based signalling devices will play an important role in future generations of remote patient monitoring equipment, both at home and in hospital. Ultimately, it will be possible to sample vital signs frompatients, whatever their location and without them necessarily being aware that a measurement is being taken. This paper reviews currentmethods for the transmission by radio of physiological parameters over ranges of 0.3, 3 and 30 m, and describes the radiofrequency hardware required and the carrier frequencies commonly used. Future developments, including full duplex systems and the use of more advanced modulation schemes, are described. The paper concludeswith a case studyof a humantemperature telemeter built to indicateovulation. Clinical results clearly show the advantage to be had in adopting radio biotelemetry in this instance.

Two type Ic supernovae in low-metallicity, dwarf galaxies: diversity of explosions

Aims. The aim of this paper is to discuss the nature of two type Ic supernovae SN 2007bg and SN 2007bi and their host galaxies. Both supernovae were discovered in wide-field, non-targeted surveys and are found to be associated with sub-luminous blue dwarf galaxies identified in SDSS images.