Jerry S. Stover · 1980
The author describes how solid-state technology transformed mobile radio equipment and paging in the 1970s. A single RF channel could serve 30 or 40 thousand pager users or 1500 voice messaging users in a metropolitan area. Equipment costs fell in real terms, with a mobile unit staying at $800 while car prices rose from $4,000 to $8,000, and a pager price fell from $300 to $150 with twice the battery life. The author cites a 1974 Department of Commerce estimate that three radio-equipped vehicles could do the work of five unequipped vehicles, saving a billion gallons of gasoline annually. However, the FCC's 1974 allocation of 115 MHz of new spectrum saw little implementation after six years.
C. F. Blackman et al. · 1980
Researchers exposed brain tissue from chicks to 147-MHz radiation amplitude modulated at 16 Hz or 9 Hz for 20 minutes. Control exposures to unmodulated carrier at 0.83 nW/cm² and to zero field-strength produced no significant differences between exposed and sham groups. Temperature control experiments showed efflux was 9% lower at 32°C and 15% higher at 41°C compared to 37°C.
Unknown authors · 1980
Joseph K. Kielman et al. · 1980
The authors reviewed experimental results from investigators worldwide on radiofrequency and microwave radiation bioeffects. Absorption of electromagnetic energy between 300 kHz and 300 GHz depends on frequency, organism geometry, and tissue dielectric properties. At power densities above 10 mW/cm2, energy dissipation can cause thermogenesis. Below 10 mW/cm2, core temperature and metabolic rate remain unchanged but biological effects are observed, including alterations in blood-brain barrier, neurotransmitter release, EEG, heart rate, immunocompetence, hematopoiesis, neuroendocrine function, and behavior. Subjective human effects such as headaches, weakness, and auditory response have also been reported.
Charles A. Cain · 1980
Kenneth A. Wickersheim, Ronald V. Alves · 1980
Electrical thermometry techniques are not practical for electrically induced heating because metallic wires reflect microwave and RF radiation and distort the heating pattern. The fluoroptic sensor uses europium-activated gadolinium oxysulfide phosphor excited by ultraviolet radiation through a single optical fiber. The sensor achieves temperature precision of 0.19°C over the range from 0° to 100°C. Probe diameters of 0.2 to 0.5mm appear feasible, with diameters approaching 0.5mm using thinner coatings on 400 micron core fibers and diameters down to 0.2mm using smaller 100 to 200 micron core fibers. Present sensors have been cycled repeatedly from 0°C to 200°C without affecting calibration.
R. Prater et al. · 1980
The project objective was to find a means for steady-state tokamak reactor operation because current tokamaks operate cyclically, causing temperature cycling of the first wall, a need for thermal energy storage, and large power handling requirements. RST uses a novel superconducting toroidal field coil concept with only three return legs and superconducting pullback coils to reduce magnetic field ripple, greatly increasing plasma access. The design specifies a major radius of 80 cm, minor radius of 20 cm, and on-axis magnetic field of 1.5 T, intended to be built in about two years for under <5M$.
Melvin A. Astrahan, F. W. George III · 1980
The authors present a temperature regulating circuit for experimental localized current field hyperthermia systems using general purpose components. The circuit uses a variable attenuator with a field effect transistor controlled by thermistor feedback to modulate radiofrequency power. The design was tested in both animal studies and patient treatment with excellent results.
David L. Conover et al. · 1980
H.F. Huang, R.A. Yates · 1980
Researchers used a platen-electrode dielectric dryer at 85 MHz and 8.5 kW to prepuff extruded fungal mycelial fibers, then finish-dried the chunks in a 60°C hot-air oven for 16 hours. The extrudate shrank about 20% in length during radio-frequency heating with little further shrinkage during finish drying. Rehydration improved as initial free interstitial water was removed, with samples prepuffed to below 70% moisture rewetting well and softness increasing as moisture decreased. The method was found viable over frequencies from 27 MHz to 2450 MHz, with resilience and hydration controlled by the prepuffing termination moisture level.
M.A. Stuchly, M.H. Repacholi, D. Lecuyer, R. Mann · 1980
Howard Bassen · 1980
Unknown authors · 1980
Researchers exposed semen specimens from fertile and infertile patients to visible light, UV light, x-rays, and high-frequency radio waves. Sperm motility was analyzed before, during, and after irradiation using the multiple exposure photography method. No significant difference was found between controls and specimens exposed to various doses of visible light, UV light, and x-rays either immediately or several hours after exposure. High-frequency radio waves had a deleterious influence on human spermatozoa.
Unknown authors · 1979
James B. Brinton · 1979
David E. Janes, Jr. · 1979
Kenji TAZAWA et al. · 1979
Zorach (Zory) R. Glaser, Ph.D. · 1979
Pacific Measurements Inc. · 1979
James C. Lin, John C. Nelson, Merlin E. Ekstrom · 1979
Researchers exposed C3H mice to 148 MHz RF energy at 0.5 mW/cm2 for one hour a day, five days a week, for 10 weeks starting shortly after birth. They monitored body weight daily for ten weeks then weekly, drew blood at multiple ages for analysis, and performed necropsy with histopathology on randomly selected animals. No effects were found on blood cells, body mass, or lesion incidence, onset, prevalence, extent, or type compared to sham controls.
Zory R. Glaser · 1979
RF sealers, heaters, and gluers are also known as heat sealers, fusers, nolders, fasteners, embossers, high frequency sealers or dryers, electronic or electromagnetic sealers or welders, and dielectric heaters. Most devices operate between 3 and 100 MHz, with sealers commonly using ISM bands at 13, 27, and 40 MHz. An estimated 20,000 sealers are in use operated by approximately 30 to 40,000 workers.
Thomas F. Budinger · 1979
Mays L. Swicord, Chairman · 1979
The Food and Drug Administration, Environmental Protection Agency, Occupational Safety and Health Administration, and Consumer Product Safety Commission announced the formation of the committee. The committee held its first meeting on October 12, 1977, and two later monthly meetings. The National Institute for Occupational Safety and Health and the Federal Emergency Management Agency participated and were invited to join the committee. The committee drafted a radiation protection philosophy statement with several recommendations.
Unknown authors · 1979
William A. Herman, Zorach R. Glaser · 1979
