High-power microwave radiation as an alternative insect control method for stored products.

ABSTRACT Insect mortality studies were performed with a high-power microwave source operating at a frequency of 10.6 GHz at power levels of 9-20 kW to irradiate samples of soft wite wheat, Triticum aestivum (L.), infested with maize weevil, Sitophilus zeamais Motschul-sky, and ground wheat infested with red flour beetle, Tribolium castaneum (Herbst). These pests are common internal and external feeders in stored products, respectively. Samples at various age intervals from egg to adult were exposed. The results support the hypothesis that the insect-to-host dissipation ratio increases at frequencies >2.45 GHz. Mean mortalities 93% occurred for all ages of S. zeamais and 94% for adults and larvae of T. castaneum for mean specific input energies of 51 J/g and 53 J/g, respectively, indicating that S. zeamais is more susceptible. Extrapolating the results to the cost of treating the product in bulk volume at a busbar electric energy cost of $0.05 per kW-h (3,600 kJ) indicates a unit cost for electric energy ranging only from$0.056 per bushel of wheat infested with S. zeamais to $0.139 per hundred weight of ground wheat infested with T. castuneum

Radio Astronomy

Contains reports on seven research projects and research objectives.National Science Foundation (Grant AST77-06052)Joint Services Electronics Program (Contract DAAG29-78-C-0020)National Aeronautics and Space Administration (Contract NAS5-21980)U.S. Department of Commerce - National Oceanic and Atmospheric Administration (Grant 04-8-M01-1)National Aeronautics and Space Administration (Contract NAS5-22929)National Aeronautics and Space Administration (Contract NAS5-25091)National Science Foundation (Grant AST77-12960)National Science Foundation (Grant AST77-26896

Radio Astronomy

Contains reports on research objectives and eight research projects.National Science Foundation (Grant AST79-25075)National Science Foundation (Grant AST79-20984)National Science Foundation (Grant AST79-19553)U.S. Navy - Office of Naval Research (Contract N00014-80-C-0348)National Aeronautics and Space Administration (Grant NAG2-50)M.I.T. Sloan Fund for Basic ResearchJoint Services Electronics Program (Contract DAAG29-78-C-0020)Joint Services Electronics Program (Contract DAAG29-80-C-0104)National Aeronautics and Space Administration (Grant NAG5-10)National Aeronautics and Space Administration (Contract NAS5-25091)National Aeronautics and Space Administration (Contract NAS5-22929)U.S. Department of Commerce - National Oceanic and Atmospheric Administration (Grant 04-8-MOl-1

Ultrasonic attenuation estimation of the pregnant cervix: a preliminary report

Estimates of ultrasonic attenuation (the loss of energy as an ultrasonic wave propagates through tissue) have been used to evaluate the structure and function of tissues in health and disease. The purpose of this research was to develop a method to estimate ultrasonic cervical attenuation during human pregnancy using a clinical ultrasound system. Forty women underwent a cervical scan once during pregnancy with the Zonare® z.one clinical ultrasound system using a 4–9-MHz endovaginal transducer. This ultrasound system provides access to radiofrequency (RF) image data for processing and analysis. In addition, a scan of a tissue-mimicking phantom with a known attenuation coefficient was acquired and used as a reference. The same settings and transducer used in the clinical scan were used in the reference scan. Digital data of the beam-formed image were saved in Digital Imaging and Communications in Medicine (DICOM) format on a flash drive and converted to RF data on a personal computer using a Matlab® program supplied by Zonare. Attenuation estimates were obtained using an algorithm that was independently validated using tissue-mimicking ultrasonic phantoms. RF data were acquired and analyzed to estimate attenuation of the human pregnant cervix. Regression analysis revealed that attenuation was: a predictor of the interval from ultrasound examination to delivery (β = 0.43, P = 0.01); not a predictor of gestational age at time of examination (β = − 0.23, P = 0.15); and not a predictor of cervical length (β = 0.077, P = 0.65). Ultrasonic attenuation estimates have the potential to be an early and objective non-invasive method to detect interval between examination and delivery. We hypothesize that a larger sample size and a longitudinal study design will be needed to detect gestational age-associated changes in cervical attenuation.This is a manuscript of an article from Ultrasound in Obstetrics & Gynecology 36 (2010): 218, doi:10.1002/uog.7643. Posted with permission.</p

Reduction of Sensitivity to Surface Roughness and Slight Standoff Distance Variations in Microwave Testing of Thick Composite Structures

Testing of thick sandwich composite structures is an important and challenging issue. Standard nondestructive testing (NDT) methods are not always capable of testing these structures for the presence of thin disbands and delaminations. However, near field microwave NDT methods have shown great potential for this purpose. Although these methods are very sensitive to the presence of thin disbands and delaminations, they are also very sensitive to changes in the standoff distance. This change can be produced as a result of the scanning procedure, surface roughness or slowly changing undulations associated with a composite specimen. This paper presents the results of an investigation in which complex sandwich composites with authentic anomalous regions were used, as well as the development of a microwave testing system capable of automatically eliminating the adverse influence of standoff distance and surface, roughness changes. Results produced at a frequency of 23.8 GHz showed many of the indications to be easily detected including a very thin disband, delamination in foam core, and impact damage. In addition, the versatility of this system to be successfully applied to very thick and relatively thinner composite structures is also demonstrated. The overall approach and its subsequent results are presented in this paper

A theoretical comparison of attenuation measurement techniques from backscattered ultrasound echoes

Accurate characterization of tissue pathologies using ultrasonic attenuation is strongly dependent on the accuracy of the algorithm that is used to obtain the attenuation coefficient estimates. In this paper, computer simulations were used to compare the accuracy and the precision of the three methods that are commonly used to estimate the local ultrasonic attenuation within a region of interest (ROI) in tissue; namely, the spectral log difference method, the spectral difference method, and the hybrid method. The effects of the inhomgeneities within the ROI on the accuracy of the three algorithms were studied, and the optimal ROI size (the number of independent echoes laterally and the number of pulse lengths axially) was quantified for each method. The three algorithms were tested for when the ROI was homogeneous, the ROI had variations in scatterer number density, and the ROI had variations in effective scatterer size. The results showed that when the ROI was homogeneous, the spectral difference method had the highest accuracy and precision followed by the spectral log difference method and the hybrid method, respectively. Also, when the scatterer number density varied, the spectral difference method completely failed, while the log difference method and hybrid method still gave good results. Lastly, when the scatterer size varied, all of the methods failed

Microwave Corrosion Detection using Open Ended Rectangular Waveguide Sensors

The use of microwave and millimeter wave nondestructive testing methods utilizing open ended rectangular waveguide sensors has shown great potential for detecting minute thickness variations in laminate structures, in particular those backed by a conducting plate. Slight variations in the dielectric properties of materials may also be detected using a set of optimal parameters which include the standoff distance and the frequency of operation. In a recent investigation, on detecting rust under paint, the dielectric properties of rust were assumed to be similar to those of Fe2O3 powder. These values were used in an electromagnetic model that simulates the interaction of fields radiated by a rectangular waveguide aperture with layered structures to obtain optimal parameters. The dielectric properties of Fe2O3 were measured to be very similar to the properties of paint. Nevertheless, the presence of a simulated Fe2O3 layer under a paint layer was detected. In this paper the dielectric properties of several different rust samples from different environments are measured. The measurements indicate that the nature of real rust is quite diverse and is different from Fe2O3 and paint, indicating that the presence of rust under paint can be easily detected. The same electromagnetic model is also used (with the newly measured dielectric properties of real rust) to obtain an optimal standoff distance at a frequency of 24 GHz. The results indicate that variations in the magnitude as well as the phase of the reflection coefficient can be used to obtain information about the presence of rust. An experimental investigation on detecting the presence of very thin rust layers (2.5-5 × 10-2 mm [0.9-2.0 × 10-3 in.]) using an open ended rectangular waveguide probe is also conducted. Microwave images of rusted specimens, obtained at 24 GHz, are also presented

Method for generating a highly reactive plasma for exhaust gas after treatment and enhanced catalyst reactivity

This patent application describes a method and apparatus of exhaust gas remediation that enhance the reactivity of the material catalysts found within catalytic converters of cars, trucks, and power stations

Diagnostic Ultrasound Safety Review for Point-of-Care Ultrasound Practitioners.

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155534/1/jum15202.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155534/2/jum15202_am.pd