Field Test Measurements Research Articles

Field test measurement for 920 MHz transmitter diversity

Field test measurements on 920 MHz transmitter diversity have been undertaken in the Tokyo metropolitan area. The proposed transmitter diversity provides at least an 8 to 10 dB required receiver input level reduction effect for 10?3 BER under a multipath fading environment. It is confirmed that the transmitter diversity is an effective technique, not only at improving transmission quality, but also at constructing a multitransmitter `simulcast? system.

Non-Linear Corona Models in an Electromagnetic Transients Program (EMTP)

Corona attenuation and distortion of overvoltage waves is an important factor in determining the overvoltage level inside the electrical system due to atmospheric lightning discharges. Simulation of overvoltage wave propagation in electrical network by digital computers is often used in the electric power industry.1,2 This paper describes the implementation of a simple and accurate numerical model representing the non-linear corona phenomenon in a general purpose electromagnetic transients program (EMTP) for lightning overvolttage studies. Single phase representation of multi-phase transmission line for short distance below 2 km are used. Field test measurements on a 600 kV line, are duplicated with the transients program and the developed corona model. Corona loss constants are also obtained empirically under different conductor configuration and wave polarities.

Energy Consumption Requirements for Air Pollution Control Equipment at An Iron Foundry

Energy consumption requirements for air pollution control equipment were studied for varying removal efficiency levels at the Tyler Pipe Industries iron foundry in Tyler, Texas, based on plant fuel consumption data, and on field test measurements of cupola carbon monoxide and particulate control equipment. Natural gas consumption for CO removal increased from 0 in 1970 to 25.4% of the plant total in 1976. Operating costs to achieve 85% CO control increased from 0 in 1970 to $1.61/ton metal in 1976. Increasing cupola incinerator temperature from 800° to 1600° F increased CO removal efficiency from 60 to 97%, but also increased natural gas consumption by 150%. Electricity consumption requirements for 95% to 97% particulate control at the foundry increased from 0.1 % of plant total in 1970 to 18.7% in 1976. Electricity consumption for particulate controls increased plant operating costs from 0.004 in 1970 to 1.693 $/ton metal in 1976 as horsepower increased from 20 to 6,272. Cost-benefit methodology is neede...

A Mechanical Model for Permafrost Thaw Subsidence

A mechanical model describing permafrost subsidence has been developed and correlated with a full scale field test performed by the Atlantic Richfield Company and Exxon Company, USA at Prudhoe Bay. The permafrost mechanical response is modeled with a linear stress-strain relation that incorporates pore pressure reduction as the subsidence loading mechanism. The pore pressure reduction is due to the phase change of pore ice upon thaw and was verified by field test measurements. The mechanical response of the well casing is included in the model with no slip assumed between casing and permafrost. The thaw subsidence model explains several features observed in the field test. The pore pressure reduction mechanism produces an upward rebound of the permafrost base, resulting in compressive casing strains above the base and tensile strains below. The pore pressure loading also produces an inward lateral motion of the thawed-frozen interface. The inward motion, together with layers of different soil types, produce the alternating compressive and tensile strains measured in the field test. These alternating strains can be significant, depending on permafrost lithology.

Use of the Gompertz Function for Predicting Corn Leaf Area

ABSTRACT ATECHNIQUE was developed to relate the coefficients A, B, and k of the Gompertz function (typical growth function) to environmental factors. Environmental factors consid-ered were maximum and minimum temperatures, rainfall, percent sun-shine, and wind speed. This procedure used regression analysis to relate the coefficients to en-vironmental factors. In this manner each day's growth reflected the en-vironment of that day. Corn leaf area was used to test the procedure. It was found that the coef-ficients were physiologically signifi-cant with respect to the environment. This is contrary to other reports. Re-sults of this procedure show that ac-ceptable estimates of leaf growth throughout the season were achieved. Using daily environmental conditions from weather bureau records, a maxi-mum leaf area of 6500 cm2 was pre-dicted as compared to actual field test measurements of 6200 cm2. This maximum was reached approximately 90 days after planting for both pre-dicted and measured growth curves.

A New High Pass Coupling Network for Power Line Carrier Operation - Field Test Report

Field tests of a new high pass coupling network for power line carrier operation are discussed. The tests pointed out several weaknesses in the coupling system as originally designed and installed. Redesign of coupling units and installation of auxiliary capacitors on the substation bus improved the attenuation characteristics and low-frequency cut-off point of the networks, resulting in satisfactory operation. Results of field test measurements are shown for the original and for the modified systems.