Terahertz Radiation from High-Temperature Superconducting BSCCO Mesas of Various Geometries

The purpose of this thesis is to examine the radiation from high-temperature superconducting mesas of Bi2Sr2CaCu2O8+ (BSCCO). This is motivated by the need for coherent sources of continuous wave terahertz (THz) emission capable of radiating practically in the THz frequency band. As BSCCO has been shown to be tunable from 0.5–2.4 THz (i.e., through the entire socalled terahertz gap centered about 1 THz), and has a higher peak operating temperature near 1 THz than most alternative sources, it is a good candidate for imaging and spectroscopy device applications [1]. When a static DC voltage is applied to a BSCCO mesa, the stack of Josephson junctions intrinsic to this type-II layered superconductor synchronously radiate. Adjustment of the bath temperature and applied voltage allows for the high degree of tunability observed for such an emitter [2]. To determine the angular dependence of radiation from BSCCO mesas, the dual source model from antenna theory is employed, and Love’s equivalence principle is used to simplify this framework. The total emission power obtained in this manner for the pie-shaped wedge is then fit to experimental results for a thin isosceles triangular mesa using the method of least squares, resulting in a standard deviation of = 0:4657. Additionally, symmetry is shown to play a significant role in the emissions for the transverse magnetic (TM) cavity modes of the equilateral triangular mesa. When the full group symmetry is imposed, the density of allowed modes is heavily diminished, and the original first excited even mode becomes the C3v symmetric ground state. These results for the equilateral triangle suggest, along with earlier experiments on the regular pentagonal mesa [3], that symmetry breaking effects can be used for purposes of tuning the characteristic frequency and angular dependence of the power radiated from BSCCO mesas with a high degree of symmetry

Cavity mode enhancement of terahertz emission from equilateral triangular microstrip antennas of the high-TcT_c superconductor Bi2_2Sr2_2CaCu2_2O8+δ_{8 + δ}

We study the transverse magnetic (TM) electromagnetic cavity mode wave functions for an ideal equilateral triangular microstrip antenna (MSA) exhibiting $C_{3v}$ point group symmetry. When the $C_{3v}$ operations are imposed upon the antenna, the TM($m,n$) modes with wave vectors $\alpha \sqrt[ ]{m^2 + nm + n^2}$ are much less dense than commonly thought. The $R_3$ operations restrict the integral $n$ and $m$ to satisfy $\mid m - n \mid$ = 3$p$, where $p \geq$ 0 and $p \geq$ 1 for the modes even and odd under reflections about the three mirror planes, respectively. We calculate the forms of representative wave functions and the angular dependence of the output power when these modes are excited by the uniform and non-uniform ac Josephson current sources in thin, ideally equilateral triangular MSAs employing the intrinsic Josephson junctions in the high transition temperature $T_c$ superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8 + \delta}$, and fit the emissions data from an earlier sample for which the $C_{3v}$ symmetry was apparently broken.UCF RAMP program, JSPS Research Fellowship for young scientists, CREST-JST (Japan Science and Technology Agency), WPI (World Premier International Research Center Initiative)- MANA (Materials Nanoarchitectonics) project (NIMS

An Evaluation of Three TRM Feed-Mixing Wagons

Three mixer wagons, three-auger, reel-type auger, and four-auger, were used to evaluate the adequacy of mix of a grower diet. All three mixers were considered in good mechanical condition. The grower diet contained 12.4% rolled corn, 23.7% wet corn gluten feed, 42% soybean hulls, 15.8% grass hay, and 6.19% liquid supplement on an as-is basis. Monensin was added to the diet at 28glton on an as-fed basis. Samples were obtained after 2, 4, 6, and 8 minutes (min) of mixing. Following the 8-min mixing time, the feed was unloaded as a windrow onto a concrete pad. Samples were obtained from the beginning, middle, and end of the windrow. These samples were used for nutrient analysis and ionophore (Monensin) recovery. Dry matter (DM) content and crude protein (CP) showed little variance across treatments. The coefficient of variation (CV) was greater for acid detergent fiber (ADF) levels than for other assayed components. The three-auger mixer produced a ration that was adequately mixed after 8 min of mixing. The reel-type auger required 4 min and the four-auger required only 2 min of mixing based on the observed CV. Monensin recovery gave similar results. The three-auger mixer gave the most accurate Monensin levels as compared to theoretical values. These studies indicate any well-maintained mixer will work well if the timing and sequence of adding ingredients is correct for the type of mixing action

Cavity mode enhancement of terahertz emission from equilateral triangular microstrip antennas of the high-TcT_c superconductor Bi2_2Sr2_2CaCu2_2O8+δ_{8 + δ}

We study the transverse magnetic (TM) electromagnetic cavity mode wave functions for an ideal equilateral triangular microstrip antenna (MSA) exhibiting $C_{3v}$ point group symmetry. When the $C_{3v}$ operations are imposed upon the antenna, the TM($m,n$) modes with wave vectors $\alpha \sqrt[ ]{m^2 + nm + n^2}$ are much less dense than commonly thought. The $R_3$ operations restrict the integral $n$ and $m$ to satisfy $\mid m - n \mid$ = 3$p$, where $p \geq$ 0 and $p \geq$ 1 for the modes even and odd under reflections about the three mirror planes, respectively. We calculate the forms of representative wave functions and the angular dependence of the output power when these modes are excited by the uniform and non-uniform ac Josephson current sources in thin, ideally equilateral triangular MSAs employing the intrinsic Josephson junctions in the high transition temperature $T_c$ superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8 + \delta}$, and fit the emissions data from an earlier sample for which the $C_{3v}$ symmetry was apparently broken.UCF RAMP program, JSPS Research Fellowship for young scientists, CREST-JST (Japan Science and Technology Agency), WPI (World Premier International Research Center Initiative)- MANA (Materials Nanoarchitectonics) project (NIMS

Terahertz emission from the intrinsic Josephson junctions of high-symmetry thermally-managed Bi2Sr2CaCu2O8+δ microstrip antennas

We show for high-symmetry disk, square, or equilateral triangular thin microstrip antennas of any composition respectively obeying C∞v, C4v, and C3v point group symmetries, that the transverse magnetic electromagnetic cavity mode wave functions are restricted in form to those that are one-dimensional representations of those point groups. Plots of the common nodal points of the ten lowest-energy non-radiating two-dimensional representations of each of these three symmetries are presented. For comparison with symmetry-broken disk intrinsic Josephson junction microstrip antennas constructed from the highly anisotropic layered superconductor Bi2 Sr2 CaCu2 O8+δ (BSCCO), we present plots of the ten lowest frequency orthonormal wave functions and of their emission power angular distributions. These results are compared with previous results for square and equilateral triangular thin microstrip antennas

The use of adherence aids by adults with diabetes: A cross-sectional survey

BACKGROUND: Adherence with medication taking is a major barrier to physiologic control in diabetes and many strategies for improving adherence are in use. We sought to describe the use of mnemonic devices and other adherence aids by adults with diabetes and to investigate their association with control of hyperglycemia, hyperlipidemia and hypertension. METHODS: Cross sectional survey of diabetic adults randomly selected from Primary Care practices in the Vermont Diabetes Information System. We used linear regression to examine the associations between the use of various aids and physiologic control among subjects who used oral agents for hyperglycemia, hypercholesterolemia, and hypertension. RESULTS: 289 subjects (mean age 65.4 years; 51% female) used medications for all three conditions. Adherence aids were reported by 80%. The most popular were day-of-the-week pill boxes (50%), putting the pills in a special place (41%), and associating pill taking with a daily event such as a meal, TV show, or bedtime (11%). After adjusting for age, sex, marital status, income, and education, those who used a special place had better glycemic control (A1C -0.36%; P = .04) and systolic blood pressure (-5.9 mm Hg; P = .05) than those who used no aids. Those who used a daily event had better A1C (-0.56%; P = .01) than patients who used no aids. CONCLUSION: Although adherence aids are in common use among adults with diabetes, there is little evidence that they are efficacious. In this study, we found a few statistically significant associations with adherence aids and better diabetes control. However, these findings could be attributed to multiple comparisons or unmeasured confounders. Until more rigorous evaluations are available, it seems reasonable to recommend keeping medicines in a special place for diabetic adults prescribed multiple medications

Cavity mode enhancement of terahertz emission from equilateral triangular microstrip antennas of the high-Tcsuperconductor Bi2Sr2CaCu2O8 +δ

We study the transverse magnetic (TM) electromagnetic cavity mode wave functions for an ideal equilateral triangular microstrip antenna (MSA) exhibiting C3v point group symmetry. When the C3v operations are imposed upon the antenna, the TM(m,n) modes with wave vectors $\propto \sqrt{{{m}^{2}}+nm+{{n}^{2}}}$ are much less dense than commonly thought. The R3 operations restrict the integral n and m to satisfy $|m-n|\,=3p$ , where $p\geqslant 0$ and $p\geqslant 1$ for the modes even and odd under reflections about the three mirror planes, respectively. We calculate the forms of representative wave functions and the angular dependence of the output power when these modes are excited by the uniform and non-uniform ac Josephson current sources in thin, ideally equilateral triangular MSAs employing the intrinsic Josephson junctions in the high transition temperature Tc superconductor Bi2Sr2CaCu2${{\text{O}}_{8+\delta}}$ , and fit the emissions data from an earlier sample for which the C3v symmetry was apparently broken

High Moisture and Dry-Rolled High-Oil Corn for Finishing Feedlot Steers

Finishing steers fed diets containing dry-rolled high-oil corn had a 2.5% reduction in dry matter intake and 4.2% better feed efficiency than steers fed diets containing dry-rolled normal corn. Hot carcass weight, dressing percent, liver abscess score, rib fat thickness, marbling score and yield grade did not differ among treatments. Steers fed high-moisture high-oil corn had larger ribeye area and greater percent kidney, pelvic and heart fat than steers fed high moisture normal corn. No differences in performance or efficiency were detected from substituting high-oil high moisture corn for normal high moisture corn

Effects of Feeding Regimen on Performance, Behavior and Body Temperature of Feedlot Steers

One hundred forty-four predominantly Angus x Charolais steers were used to determine effects of different feeding regimens on performance, behavior and tympanic temperatures of steers under environmental heat stress. Steers were assigned to one of three treatments: 1) ad libitum fed at 0800 hr (ADLIB); 2) fed at 1600 hr with bunks slick by 0800 hr (BKMGT); and 3) fed 85% of predicted DMI at 1600 hr (LIMFD). Treatments were imposed for 23 days after which all steers were allowed ad libitum access to feed at 0800 hr. Overall performance was not affected by treatment. Altering feed time and amount reduced tympanic temperature and altered eating pattern

Managing Heat Stress in Feedlot Cattle Using Sprinklers

Ninety-six Bos taurus steers were used to determine the effect of water application to feedlot mounds on performance, behavior and tympanic temperature of steers and microclimatic conditions of the mounds. Steers were assigned to 12 pens subjected to no water application (CON), water applied between 1000 and 1200 (AM), or 1400 and 1600 hr (PM). Water application lowered soil temperatures of the mounds with little effect on temperature-humidity index. Tympanic temperatures were lowered by treatment. Performance variables were not affected; however, AM steers were more efficient than PM steers