Investigation of dynamic stresses in detona- tion technical note no. 7

Axial and hoop stress calculation in blast loaded thin walled cylindrical pressure vessel

Impact of sagebrush nutrients and monoterpenes on greater sage-grouse vital rates

Greater sage-grouse (Centrocercus urophasianus; sage-grouse) depend on sagebrush (Artemisia spp.) to complete its annual life cycle. The winter diet for sage-grouse consists almost entirely of sagebrush leaves, and individual birds may gain weight while foraging on sagebrush. Previous studies have reported higher crude protein and lower monoterpene concentrations in the sagebrush species selected as winter forage by sagegrouse. However, no studies have attempted to link female sage-grouse vital rates (i.e., nest initiation and success, egg fertility, clutch size, and adult survival) to crude protein or monoterpene concentrations of sagebrush plants browsed during pre-nesting periods. From March to May 2013, we monitored pre-nesting diets for 29 radio-marked female sage-grouse in the Box Elder Sage-grouse Management Area in northwestern Utah to determine if a relationship existed between foraging patterns and vital rates. We randomly located radiomarked female sage-grouse ≥3 times during the study period and subsequently sampled 70 sagebrush communities where they were observed to determine which sagebrush species or subspecies were browsed and if samples collected of the browsed plants differed in nutritional quality (i.e., crude protein) and chemical composition (i.e., monoterpenes) from non-browsed plants in the areas sampled and non-browsed randomly selected plants in adjacent sagebrush communities. Seventy-three percent of these sites where radio-marked females were located consisted entirely of black sagebrush (A. nova) communities. Percent crude protein and total monoterpene concentration in black sagebrush and Wyoming big sagebrush (A. tridentata wyomingensis) did not diff er between browsed, non-browsed, and non-browsed random plants. Browsed black sagebrush plants were lower in average percent crude protein (P = 0.003) and higher in total monoterpene concentration (P ≤ 0.001) than browsed Wyoming big sagebrush. Apparent nest success, age of nesting females, egg fertility, clutch size (P \u3e 0.05), and female monthly survival rates (CI = -0.21–0.49) for the radio-marked sagegrouse we monitored did not diff er based on sagebrush crude protein and total monoterpene content. However, all of the radio-marked female sage-grouse (n = 10) observed in black sagebrush communities where the collected plant samples exhibited higher concentrations of an unidentified monoterpene successfully hatched nests (P = 0.002). All of the nests of radiomarked female sage-grouse (n = 9) outside these areas failed. Our results lend additional support to previous published work regarding sage-grouse preferences for black sagebrush as pre-nesting forage and suggest a potential link to nest success

Detection of H_2 Pure Rotational Line Emission from the GG Tauri Binary System

We present the first detection of the low-lying pure rotational emission lines of H_2 from circumstellar disks around T Tauri stars, using the Short Wavelength Spectrometer on the Infrared Space Observatory. These lines provide a direct measure of the total amount of warm molecular gas in disks. The J = 2 → 0 S(0) line at 28.218 μm and the J = 3 → 1 S(1) line at 17.035 μm have been observed toward the double binary system GG Tau. Together with limits on the J = 5 → 3 S(3) and J = 7 → 5 S(5) lines, the data suggest the presence of gas at T_(kin) ≈ 110 ± 10 K with a mass of (3.6 ± 2.0) × 10^(-3) M_☉ (±3 σ). This amounts to ~3% of the total gas + dust mass of the circumbinary disk as imaged by millimeter interferometry, but it is larger than the estimated mass of the circumstellar disk(s). Possible origins for the warm gas seen in H_2 are discussed in terms of photon and wind-shock heating mechanisms of the circumbinary material, and comparisons with model calculations are made

Analisis Pengaruh Ketebalan Nonconductive Coating Terhadap Kemampuan Pendeteksian Panjang Dan KedalamanRetak PadaFilletJoint Bracket KapalAluminium Menggunakan Pengujian Ultrasonik

Konstruksi kapal yang telah beroperasi seringkali terjadi cacat pada daerah lasnya.Cacat yang timbul seperti retak,seringterjadi tanpa disadari padasambungan las yang telah dilapisi cat sebelumnya.Retak tersebut dapat diperiksa menggunakan metode Ultrasonic testing tanpa menghilangkan cat yang terdapat pada sambungan las. Penelitian ini bertujuan untuk menganalisis pengaruh ketebalan cat tersebut terhadap pendeteksian retak dengan metode Ultrasonic testing padafillet joint di braket kapal aluminium.Scanning dilakukan pada face C dari spesimen uji. Pada setiap spesimen diberikan beberapa variasi ketebalan nonconductive coating yaitu 100 mikron, 200 mikron, 250 mikron dan 300 mikron dimana sebelum diberikan variasi ketebalan coating, spesimen terlebih dahulu diberikan retak buatan pada daerah toe las dengan variasi ukuran panjang 70 mm, 30 mm, 20 mm, dan 10 mm, dengan kedalaman 2 mm, 4 mm, 6 mm, dan 8 mm. Setelah itu tiap spesimen dilakukan pemeriksaan dengan menggunakan metode Ultrasonic testing (UT). Hasil penelitian ini menunjukkan bahwa terdapat pengaruh ketebalan nonconductive coating terhadap pendeteksian panjang dan kedalaman retak, dimana kemampuan pembacaan UT terhadap panjang retak pada spesimen dengan ketebalan nonconductive coating 100 mikron rata-rata sebesar 95,814 %, 200 mikron sebesar 89,510 %, 250 mikron sebesar 87,140 % dan 300 mikron sebesar 85,629 % dari ukuran panjang retak sebenarnya. Sedangkan kemampuan pembacaan UT terhadap kedalaman retak pada spesimen dengan ketebalan nonconductive coating 100 mikron rata-rata sebesar 99,219 %, 200 mikron sebesar 98,167 %, 250 mikron sebesar 97,396 % dan 300 mikron sebesar 96,625 % dari ukuran kedalaman crack sebenarnya. Hal ini disebabkan adanya pelemahan gelombang ultrasonik (atenuasi) pada saat gelombang ultrasonik melewati batas permukaan antara nonconductive coating dengan pelat aluminium yang mempunyai impedansi akustik berbeda maka akan terjadi pemantulan dan pembiasan gelombang ultrasonik. Sebagian energi gelombang ultrasonik juga akan hilang saat gelombang melewati interfaces material

Dynamic Boundaries in Asymmetric Exclusion Processes

We investigate the dynamics of a one-dimensional asymmetric exclusion process with Langmuir kinetics and a fluctuating wall. At the left boundary, particles are injected onto the lattice; from there, the particles hop to the right. Along the lattice, particles can adsorb or desorb, and the right boundary is defined by a wall particle. The confining wall particle has intrinsic forward and backward hopping, a net leftward drift, and cannot desorb. Performing Monte Carlo simulations and using a moving-frame finite segment approach coupled to mean field theory, we find the parameter regimes in which the wall acquires a steady state position. In other regimes, the wall will either drift to the left and fall off the lattice at the injection site, or drift indefinitely to the right. Our results are discussed in the context of non-equilibrium phases of the system, fluctuating boundary layers, and particle densities in the lab frame versus the frame of the fluctuating wall.Comment: 13 page

Semiclassical theory of the effects of collisions between rotors on molecular spectral lineshapes. II. Calculations for several systems

The T2 (microwave line broadening) and T1 (microwave transient experiments) collisional cross sections are obtained by Monte Carlo trajectory evaluations of semiclassical (WKB) expressions for those quantities derived in a previous paper in this series. The calculated values of the cross sections presented here yields the relation T1~T2 (within standard error) for the systems OCS–OCS, OCS–N2, OCS–H2, OCS–CO2, and HCN–HCN, a result which agrees with recent experimental findings. Reasonable agreement was also found between the calculated values of the T2 cross section and those observed spectroscopically

A New Large Super-Fast Rotator: (335433) 2005 UW163

Asteroids of size larger than 150 m generally do not have rotation periods smaller than 2.2 hours. This spin cutoff is believed to be due to the gravitationally bound rubble-pile structures of the asteroids. Rotation with periods exceeding this critical value will cause asteroid breakup. Up until now, only one object, 2001 OE84, has been found to be an exception to this spin cutoff. We report the discovery of a new super-fast rotator, (335433) 2005 UW163, spinning with a period of 1.290 hours and a lightcurve variation of $r'\sim0.8$ mag from the observations made at the P48 telescope and the P200 telescope of the Palomar Observatory. Its $H_{r'} = 17.69 \pm 0.27$ mag and multi-band colors (i.e., $g'-r' = 0.68\pm0.03$ mag, $r'-i' = 0.19\pm0.02$ mag and SDSS $i-z = -0.45$ mag) show it is a V-type asteroid with a diameter of $0.6 +0.3/-0.2$ km. This indicates (335433) 2005 UW163 is a super-fast rotator beyond the regime of the small monolithic asteroid.Comment: 18 pages, 4 figures, 1 table Accepted by ApJ

Quantitative atomic spectroscopy for primary thermometry

Quantitative spectroscopy has been used to measure accurately the Doppler-broadening of atomic transitions in $^{85}$Rb vapor. By using a conventional platinum resistance thermometer and the Doppler thermometry technique, we were able to determine $k_B$ with a relative uncertainty of $4.1\times 10^{-4}$, and with a deviation of $2.7\times 10^{-4}$ from the expected value. Our experiment, using an effusive vapour, departs significantly from other Doppler-broadened thermometry (DBT) techniques, which rely on weakly absorbing molecules in a diffusive regime. In these circumstances, very different systematic effects such as magnetic sensitivity and optical pumping are dominant. Using the model developed recently by Stace and Luiten, we estimate the perturbation due to optical pumping of the measured $k_B$ value was less than $4\times 10^{-6}$. The effects of optical pumping on atomic and molecular DBT experiments is mapped over a wide range of beam size and saturation intensity, indicating possible avenues for improvement. We also compare the line-broadening mechanisms, windows of operation and detection limits of some recent DBT experiments