Analytical Distribution of Waiting Time in the M/{iD}/1 Queue

We give an analytical formula for the steady-state distribution of queue-wait in the M/G/1 queue, where the service time for each customer is a positive integer multiple of a constant D > 0. We call this an M/{iD}/1 queue. We give numerical algorithms to calculate the distribution. In addition, in the case that the service distribution is sparse, we give revised algorithms that can compute the distribution more quickly.AMS subject classification: 60K25, 90B22     

Horizons in 2+1-dimensional collapse of particles

A simple, geometrical construction is given for three-dimensional spacetimes with negative cosmological constant that contain two particles colliding head-on. Depending on parameters like particle masses and distance, the combined geometry will be that of a particle, or of a black hole. In the black hole case the horizon is calculated. It is found that the horizon typically starts at a point and spreads into a closed curve with corners, which propagate along spacelike caustics and disappear as the horizon passes the particles.      

Heat conduction in the vortex state of NbSe2: evidence for multiband superconductivity

The thermal conductivity kappa of the layered s-wave superconductor NbSe2 was measured down to T(c)/100 throughout the vortex state. With increasing field, we identify two regimes: one with localized states at fields very near H(c1) and one with highly delocalized quasiparticle excitations at higher fields. The two associated length scales are naturally explained as multiband superconductivity, with distinct small and large superconducting gaps on different sheets of the Fermi surface. This behavior is compared to that of the multiband superconductor MgB2 and the conventional superconductor V3Si.     

Bestimmung geringer Zirkoniumgehalte einiger technischer Legierungen durch Röntgenfluorescenz von Zirkoniumphenylarsonat

Zirconium may be separated to a highly selective degree by phenylarsonic acid from strong acid aqueous solutions of aluminium-, copper-, chrome-nickel-iron- and iron-base alloys. The precipitation film deposited on Millipore Filters is suitable for determining zirconium by X-ray fluorescence. By this way concentrations of zirconium were determined in the range of 0.002–1%.     

Hyperfine fields and Mössbauer isomer shifts of 57Fe in PdAgFe alloys

The hyperfine fields B_hf and Mössbauer isomer shifts S of ⁵⁷Fe in two PdAgFe alloy series containing 3 and 7 at% have been measured at 4.2 K and 295 K. With increasing Ag content, a change in the magnetic ordering from ferromagnetism towards a spin-glass behaviour is indicated in the 3 at% Fe series.     

The109Ag Knight shift in the palladium-silver alloy system

The¹⁰⁹Ag Knight shiftK in the PdAg system has been observed at 298 K. The temperature dependence of the shift is presented in conjunction with the data of Narath at 4 K. The shift is found to be temperature dependent for silver concentrations less than 60 at. %. An analysis ofK in terms of thes andd electron contributions shows that thes electron density of states at the Fermi energy is in agreement with a commons band uniformly filled at the Pd and Ag sites and thatK _d is linearly related to the susceptibility of the PdAg system with both the temperature and the alloy concentration as implicit parameters.     

Reaktionen im aktiviert adsorbierten Zustand Ein Beitrag zur Reaktions-Chromatographie

Ohne Zusammenfassung     

Assessment of dolphin (Tursiops truncatus) auditory sensitivity and hearing loss using jawphones

Devices known as jawphones have previously been used to measure interaural time and intensity discrimination in dolphins. This study introduces their use for measuring hearing sensitivity in dolphins. Auditory thresholds were measured behaviorally against natural background noise for two bottlenose dolphins (Tursiops truncatus); a 14-year-old female and a 33-year-old male. Stimuli were delivered to each ear independently by placing jawphones directly over the pan bone of the dolphin's lower jaw, the assumed site of best reception. The shape of the female dolphin's auditory functions, including comparison measurements made in the free field, favorably matches that of the accepted standard audiogram for the species. Thresholds previously measured for the male dolphin at 26 years of age indicated a sensitivity difference between the ears of 2-3 dB between 4-10 kHz, which was considered unremarkable at the time. Thresholds for the male dolphin reported in this study suggest a high-frequency loss compared to the standard audiogram. Both of the male's ears have lost sensitivity to frequencies above 55 kHz and the right ear is 16-33 dB less sensitive than the left ear over the 10-40 kHz range, suggesting that males of the species may lose sensitivity as a function of age. The results of this study support the use of jawphones for the measurement of dolphin auditory sensitivity.     

Electromechanical response of sliding charge-density-waves: Voltage-induced torsional strain in tantalum trisulfide

We have measured the hysteretic voltage-induced torsional strain (VITS) in orthorhombic tantalum trisulfide as functions of voltage, temperature, and torque, which was applied by attaching a small magnetic rod to the center of the sample. We have found that the magnitude, speed, and even direction of the VITS hysteresis loops varied with the applied torque, suggesting that the VITS is a consequence of residual torsional strains in the sample interacting with hysteretic, voltage-induced changes of the charge-density-wave wave vector. The VITS response time is much longer than the time needed for the wave vector to change with response to either applied stress or applied voltage and varies inversely with the CDW current, suggesting that the VITS response requires motion of CDW defects.