Buried ordnance detection: electromagnetic modeling of munition-mounted radio frequency identification tags

In order to improve means for locating unexploded ordnance items (UXO) and significantly discriminating UXO from clutter, it is desired to tag ordnance items before they are delivered. The munition tagging envisioned will make use of current passive radio frequency identification (RFID) tag technology. The tags will provide information on the munition's location and identity when the UXO tag interrogation module is brought nearby. Knowledge of the magnetic field's behavior is essential in understanding the designs required to transmit energy from the above-ground interrogator to the tag and from the tag back to the above-ground receiver. The munition, being a large metal structure in such close proximity to the tags, will affect their operation because of electromagnetic boundary conditions and the tags' specific circuitry. To this end, modeling of the magnetic fields was required. This paper presents the results of this modeling effort and includes experimental findings. The modeling efforts demonstrated that detection depths to 1 m would be achievable, provided the system is magnetically optimized.     

Measuring the translatability of Simplified English in proceduraldocuments

The paper reports the results of a study that tested the translatability of a restricted language, called Simplified English (SE), as used in maintenance procedures in the airline industry. The study examined the effect of document type (SE versus non-SE) and procedure (procedure A versus procedure B) on the quality and ease of translation for native speakers of Spanish, Chinese, or Japanese. The results reveal that SE may be more effectively translated by native Spanish speakers than by Chinese speakers. The paper concludes with a discussion of methodological issues that researchers should consider when running such translation studies     

Application of a new selection algorithm to the development of a wide-range equation of state for refrigerant R134a

Refrigerant R134a (1,1.1,2-tetrafuoroethane) is a leading substitute for refrigerant R12. As such, there has been worldwide activity to develop accurate wide-range equations of state for this fluid. In this study. we have developed a new selection algorithm for determining high-accuracy equations of state in the Helmholtz representation. This method combines least-squares regression analysis with simulated annealing optimization. Simulated annealing, unlike stepwise regression, allows for the controlled acceptance of random increases in the objective function. Thus, this procedure produces a computationally efficient selection algorithm which is not susceptible to the function-space local-minima problems present in a purely stepwise regression approach. Two equations are presented in this work and compared against experimental data and other high-accuracy equations of state for R134a. One equation was produced strictly by using stepwise a regression algorithm, while the other was produced using the simulated-annealing selection algorithm. In both cases the temperature dependence of the equations was restricted to have no terms whose exponents were greater than live.Paper presented at the Twelfth Symposium on Thermophysical Properties. June 19–24, 1994, Boulder, Colorado, U.S.A.     

SAR processing of ground-penetrating radar data for buried UXOdetection: results from a surface-based system

Battelle and The Ohio State University ElectroScience Laboratory have built and demonstrated a ground-penetrating radar (GPR) system for locating buried unexploded ordnance (UXO), the system is ground based and towed by an autonomously controlled vehicle as part of the subsurface ordnance characterization system (SOCS). This paper presents the results of the synthetic aperture radar (SAR) processing of the radar data acquired at Tyndall Air Force Base, FL, and Jefferson Proving Ground (JPG), IN     

Synthetic radar imagery

A method for producing three-dimensional isometric images of a conducting radar target from measured ramp response waveforms is tested for the case of nonmutually orthogonal viewing angles. It is found that, in general, image quality is somewhat degraded and several new parameters are introduced, but useful images can still be obtained. Methods for obtaining the new parameters are included as well as other modifications which were developed to enhance image quality. Images of three aerospace-type targets obtained from low frequency scattering data are presented.     

A standoff, focused-beam land mine radar

This paper describes a standoff, focused-beam, ground-penetrating radar (GPR) for detecting buried antipersonnel (AP) mines. The radar features a 1 to 6 GHz, pulsed stepped-frequency microwave source with hardware range gate, an ultrawide bandwidth feed antenna, and an offset parabolic reflector. A focused-beam, created by feeding the reflector from an offset position, reduces the surface clutter and improves the detection of buried mines. A processing technique based on spectral analysis (Prony method) is developed in an attempt to reduce surface clutter. Tests conducted at the Fort A.P. Hill countermine test lanes showed excellent detection capability for both metallic and nonmetallic mines     

Mechanism of cold plastic deformation of sintered iron

Conclusions The observed difference in the rate of strain hardening of sintered and case iron may be due to rotation of the particles in the process of cold plastic deformation of the P/M material, leading to substantial stress relaxation. The characteristics of the mechanism of plastic deformation in sintered materials must be kept in mind in developing techniques of cold bulk pressing, particularly to reduce deformation stresses.PO ZIL. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 2–5, October, 1982.     

The Virtual Interface Architecture

This protected, zero-copy, user-level network interface architecture reduces the system overhead for sending and receiving messages between high-performance CPU/memory subsystems and networks to less than 10 microseconds when integrated in silicon