PubMed · 4650944
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H Weber, I Weber. 1972. [Useful transillumination device].. https://pubmed.ncbi.nlm.nih.gov/4650944/
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OBJECTIVE: To determine the real emitted output power and maximum surface heating of commercial therapeutic ultrasound transducers emitting in air for various therapeutic regimens. DESIGN: Surface temperatures of ultrasound transducers with frequencies of .05 to 3 MHz were detected over 5 minutes by using a calibrated infrared thermographic camera; additionally, the indicated output power was checked with a radiation force balance. SETTING: University center for biomedical engineering and physics and medical school for physical medicine and rehabilitation. PARTICIPANTS: Not applicable. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Power variations and surface temperatures of clinical devices were analyzed to determine whether they comply with obligatory limits given in International Electrotechnical Commission standard 60601-2-5. RESULTS: Depending on the operation mode and the output power, surface temperatures ranged between 24.2 degrees to 80 degrees C within 5 minutes. Differences between measured and displayed power output (limit, +/-20%) ranged between -32% and 28%. CONCLUSIONS: The effectiveness of treatment is lowered if the value of emitted power is not known reliably. In the worst case, damage or irritation of the skin is possible, particularly in patients with sensory compromised skin. Damage may be caused by hot surfaces if the threshold level required to activate the device is lowered or if the device is defective. Improved thermal control units are necessary to prevent potential thermal hazards. Regular checks of transducer emission should be obligatory to ensure correct and precise function of the clinical devices.
This study was aimed at investigating the further formation of trihalomethanes (THM) in drinking water when it is being heated at home. Experimental results confirmed that there could be a further significant formation during heating drinking water. Overall variation of THM concentration in water during the heating depended on its formation rate and volatilisation rate. The rate of THM formation was mainly affected by not only both the concentrations of THM precursors, such as humic substances and residual chlorine, but also temperature and reaction time. The rate of THM volatilisation depended on water temperature and the extent of water agitation in the water heaters. It was concluded that the THM residuals in drinking water could be effectively eliminated to a very low level, if the boiling of water was kept in the open for few minutes after water boiling.
Microclimatic measurements were conducted in the canopy gap of tropical secondary forest in Xishuangbanna in fog-cool and dry-hot season. The daytime thermal effect of different thermal active surface in the canopy gap was discussed, and the variations of trunk surface temperature near gap edge and of surface temperature on the gap were analyzed. The result shows that the woody-wall surface is new thermal active surface on the vicinage of canopy gap, with the exception of the forest canopy surface, soil surface in the forest gap, and soil surface of the interior. Because of the influence of season, situs and time, the thermal effect of different thermal active surface of gap was significant different. Being subject to fog, the soil surface on the center of canopy gap is an important thermal active surface in the morning; while in the midday and afternoon, because of the influence of incident radiation, the woody wall and soil surface of edge on the east and the woody wall surface of edge on the north are the key thermal active surface of the canopy gap. In the midday, the thermal active was salient on the surface of gap, and in the afternoon, it was salient on the woody wall. The thermal variations of canopy gap of forest are controlled by the thermal characteristics of different thermal active surfaces and by their interaction, affecting the growth of plants.