Operation of SiGe BiCMOS Technology Under Extreme Environments Tianbing Chen 96 pages Directed by Dr. John D. Cressler "Extreme environment electronics" represents an important niche market and spans the operation of electronic components in surroundings lying outside the domain of conventional commercial, or even military specifications. Such extreme environments would include, for instance, operation to very low temperatures (e.g., to 77 K or even 4.2 K), operation to very high temperatures (e.g., to 200 C or even 300 C), and operation in a radiation-rich environment (e.g., space). The suitability of SiGe BiCMOS technology for extreme environment electronics applications is assessed in this work. The suitability of SiGe HBTs for use in high-temperature electronics applications is first investigated. SiGe HBTs are shown to exhibit sufficient current gain, frequency response, breakdown voltage, achieve acceptable device reliability, and improved low-frequency noise, at temperatures as high as 200-300 C. A comprehensive investigation of substrate bias effects on device performance, thermal properties, and reliability of vertical SiGe HBTs fabricated on CMOS-compatible, thin-film SOI, is presented. The impact of 63 MeV protons on these vertical SiGe HBTs fabricated on a CMOS-compatible SOI is then investigated. Proton irradiation creates G/R trap centers in SOI SiGe HBTs, creating positive charge at the buried oxide interface, effectively delaying the onset of the Kirk effect at high current density, which increases the frequency response of SOI SiGe HBTs following radiation. The thermodynamic stability of device-relevant epitaxial SiGe strained layers under proton irradiation is also investigated using x-ray diffraction techniques. Irradiation with 63 MeV protons is found to introduce no significant microdefects into the SiGe thin films, regardless of the starting stability condition of the SiGe film, and thus does not appear to be an issue for the use of SiGe HBT technology in emerging space systems. CMOS device reliability for emerging cryogenic space electronics applications is also assessed. CMOS device performance improves with cooling, however, CMOS device reliability becomes worse at decreased temperatures due to aggravated hot-carrier effects. The device lifetime is found to be a strong function of gate length, suggesting that design tradeoffs are inevitable.

The distribution of apple snail Pomacea canaliculata are island-wide but Pomacea scalaris is only found in southern Taiwan. In order to gain more information on the not well-known alien invasive species, comparative studies on the reproduction and thermal tolerance of P. canaliculata and P. scalaris were conducted. Sexual dimorphism in shell morphology has been found in both species, with wider operculum in males. Positive correlation between shell length and penis sheath length or penis length has been observed in male P. canaliculata and P. scalaris, based on the samples collected during the period of December 2004 and March 2006, The width of penis sheath in P. canaliculata was greater than in P. scalaris. Positive correlation between shell length and the height and width of vestigial penis in female P. canaliculata and P. scalaris was also found. The width of vestigial penis in P. scalaris was greater than in P. canaliculata. Gonadosomatic index (GSI) in male P. canaliculata and P. scalaris was 68 and 60% and 31 and 33% in females. Their reproductive cycle was annual without seasonal peaks. Significant difference in thermopreferrenda was found between P. canaliculata and P. scalaris. The 24, 48 and 72-h lethal thermal minima temperatures in P. canaliculata and P. scalaris were similar, i.e. 9.8¡V11.8¢J. And, the 24, 48 and 72-h lethal thermal maxima temperatures were 33.1¡V35.9¢J. Based on the results, it is known that P. canaliculata and P. scalaris reproduce year-round and temperature is not a major factor in shaping the species distribution pattern in Taiwan.

No description available.

Thesis (M.D.)--Dublin.

Issued also as Thesis (Ph. D.)--Columbia University. / Bibliography: p. 79-81.

Soil moisture and temperature are two important soil parameters that influence many vital agronomic, environmental, engineering processes within the soil. Due to the difficulties arising when measuring these parameters in the field as well as the cost of instrumentation, many models that yield accurate and timely estimation of these parameters on a large scale have been developed as reliable and efficient alternatives. The Versatile Soil Moisture Budget model can be used to stimulate the vertical, one dimensional, water balance in a soil profile. Originally the model was designed to use air temperature and precipitation data to simulate soil water content within the root zone of a cereal crop. It has since undergone modifications and the model can now output, potential evapo-transpiration, actual evapo-transpiration, and surface temperature. The temperature algorithm simulates temperature at the soil surface and has not been rigorously tested for cropping systems. In this study, a simple empirical equation that simulates soil temperature at depth of up to 90 cm was introduced into the model. The model was evaluated and the accuracy of predicted soil moisture and temperature under both perennial and annual cropping systems were tested using two years of data collected at the University of Manitoba Research Station at Carman using soil water and temperature probes. The model’s accuracy in simulating soil moisture was also tested. Observed R2 comparing modelled temperature with observed was greater than 0.90 at the soil surface but decreased to about 0.40 at soil depth greater than 30-45 cm layer. The model was shown to be better at estimating soil temperature than soil moisture. The accuracy of the model was also shown to decrease with depth. These results can be used to improve soil temperature modeling at depth as well as improve farm management planning, irrigation schedules, nutrient management, fertilizer application and drought monitoring. / October 2015

M. Tech. Civil Engineering / Climatic data is one of the most important inputs required in any road design. The historical information being currently relied upon for pavement design may soon lose its significance due to the expected global climate change. The broad objective of the study was to determine and simulate future climate change for road sub-grades in the southern African region, with a view to developing new pavement design parameters in order to protect the pavement infrastructure.

The cardiovascular effects of whole body heat stress during exercise are well established. However the independent contribution of elevated skin temperature (Tsk) or core temperature (Tc) on these responses remains unclear. The purpose of this study was to determine how increases in Tsk and Tc alone and in combination, impact cardiovascular responses during moderate intensity exercise. To accomplish this goal, eight healthy, recreationally active males were immersed to the neck in a cold (14 - 17°C) or hot (40 - 42.5°C) water bath for 20 to 25 min to alter Tc immediately prior to exercise with either cool Tsk (i.e. fans) or warm Tsk (i.e. heaters). Conditions during exercise were cool skin and cool core (CC), warm skin and cool core (WC), cool skin and warm core (CW), and warm skin and warm core (WW), and were conducted in a randomized crossover design. When data was combined (n=16), warm core conditions (CW and WW) were associated with significantly higher average heart rate (HR) and lower stroke volume (SV) during exercise compared to cool core conditions (CC and WC); 168.1 ± 3.2 vs. 152.2 ± 4.0 beats/min and 139.2 ± 7.3 vs. 147.7 ± 9.4 mL/beat, respectively. The approximate 9 mL/beat decline in SV and 16 beat/min increase in HR in warm core conditions tended to increase cardiac output (Q), 23.2 ± 0.6 vs. 22.2 ± 0.7 L/min, P=0.078. Similarly, warm Tsk conditions (WC and WW) were associated with significantly higher average HR and lower SV during exercise compared to cool Tsk conditions (CC and CW); 165.2 ± 3.3 vs. 155.1 ± 3.4 beats/min and 140.8 ± 7.8 vs. 146.0 ± 8.7 mL/beat, respectively. Additionally, there was also a trend for Q to be elevated with warm skin (23.0 ± 0.6 vs. 22.4 ± 0.6, P=0.075). Although combined data indicated that warm Tsk conditions significantly lowered average SV by ~6 mL/beat, there was no reduction in SV during exercise by warm Tsk, when Tes was cool (i.e. <37.0°C), as evidenced by identical values for SV in CC and WC, 147.7 ± 9.8 vs. 147.7 ± 9.0 mL/beat, respectively. In contrast, SV was significantly lower in WW compared with CW, 133.9 ± 7.0 vs. 144.4 ± 7.8 mL/beat, respectively. Therefore, the major reduction in SV by warm Tsk occurred during WW, when Tes was elevated (i.e. >38.0°C). Analyzing data independently for precooling and preheating conditions revealed that warm Tsk was associated with greater HR drift from 5 to 20 min of exercise, compared to cool Tsk, when esophageal temperature (Tes) was both cool or warm (23.9 ± 2.2 vs. 17.5 ± 2.3 and 12.3 ± 1.3 vs. 4.6 ± 1.7 beats/min, respectively). These observations demonstrate that both Tes and Tsk can directly influence cardiovascular responses during exercise, as indicated by elevations in HR during exercise with warm Tsk, with both warm and cool Tes. However SV is not compromised by warm Tsk if Tes is below 37.5°C. Furthermore, when both Tes and Tsk are elevated simultaneously, cardiovascular strain (i.e. increased HR and reduced SV) is much greater than when either is elevated alone. This is demonstrated by the finding that average HR was 175.8 ± 3.2 beats/min in WW, compared to 149.8 ± 4.0, 154.7 ± 4.1, and 160.3 ± 3.5 beats/min, in CC, WC, and CW, respectively, and the fact that SV was lowest during exercise in WW. In conclusion, individuals exercising in the heat should take measures to keep skin cool, especially when Tes is 39°C or greater to attenuate the cardiovascular strain that occurs with warm Tsk, when Tes is elevated. / text

The spectral width of single-frequency radiation scattered in the atmosphere may be used to determine air temperature. In general, the measurement is complicated by pressure dependent changes in the spectral profile of the scattered radiation and by the inherently low received signal levels. A fixed-delay Michelson interferometer minimizes both of these problems by: (1) exhibiting a low sensitivity to pressure induced changes in the scattered spectrum and (2) optimally utilizing the available signal. By frequency shifting the signal in one arm of the interferometer relative to the other it is possible to efficiently modulate the output of the interferometer and make it insensitive to small changes in the center frequency of the scattered spectrum. Laboratory results obtained using a fixed-delay, frequency-shifted Michelson interferometer demonstrate the ability of this instrument to remotely measure air temperatures in the range 290 K to 310 K with an uncertainty of ±2 K with averaging times on the order of seconds at a received signal level of 6 x 10⁻¹⁰ watts.

The objective of this study was to determine the ability of a passive temperature monitoring system consisting of radio frequency identification (RFID) boluses with thermistors and receiver panels to detect ovulation in high performing dairy cows. The twice-daily reticulo-rumen temperature (Trr) acquisitions of 41 early-lactation Holstein dairy cows were analyzed. The data were analyzed using two criteria: six baseline days (2d, 3d, 4d, 5d, 6d, 7d) and four temperature deviations (0.2°C, 0.3°C, 0.4°C, 0.5°C). The best criteria were chosen by selecting the baseline/deviation combination that gave the best positive predictive value (PPV). The system detected 93 true positive and 267 false positive alerts of ovulation, with a monitoring rate (MR) of 47% and a PPV of 46.2%. There were indications that the Cow Temperature Monitoring System could have a future as an ovulation detection aid, but due to the unreliability of the Wi-Fi transmission of acquisitions, more research needs to be conducted before definite conclusions can be drawn.