Magnetic blackbody shift of hyperfine transitions for atomic clocks

We derive an expression for the magnetic blackbody shift of hyperfine transitions such as the cesium primary reference transition which defines the second. The shift is found to be a complicated function of temperature, and has a T^2 dependence only in the high-temperature limit. We also calculate the shift of ground-state p_1/2 hyperfine transitions which have been proposed as new atomic clock transitions. In this case interaction with the p_3/2 fine-structure multiplet may be the dominant effect

Rotating Metal Band Target for Pion Production at Muon Colliders and Neutrino Factories

A conceptual design is presented for a high power pion production target for muon colliders and neutrino factories that is based around a rotating metal band.Comment: 28 pages, 16 figures; to be published in Phys. Rev. ST Accel. Beam

Study of fuel cell powerplant with heat recovery

It was shown that heat can be recovered from fuel cell power plants by replacing the air-cooled heat exchangers in present designs with units which transfer the heat to the integrated utility system. Energy availability for a 40-kW power plant was studied and showed that the total usable energy at rated power represents 84 percent of the fuel lower heating value. The effects of design variables on heat availability proved to be small. Design requirements were established for the heat recovery heat exchangers, including measurement of the characteristics of two candidate fuel cell coolants after exposure to fuel cell operating conditions. A heat exchanger test program was defined to assess fouling and other characteristics of fuel cell heat exchangers needed to confirm heat exchanger designs for heat recovery

Differential constraints and exact solutions of nonlinear diffusion equations

The differential constraints are applied to obtain explicit solutions of nonlinear diffusion equations. Certain linear determining equations with parameters are used to find such differential constraints. They generalize the determining equations used in the search for classical Lie symmetries

Is there further evidence for spatial variation of fundamental constants?

The detection of a spatial variation of the fine-structure constant, alpha, based on study of quasar absorption systems has recently been reported. The physics that causes this alpha-variation should have other observable manifestations, and this motivates us to look for complementary astrophysical effects. In this paper we propose a method to test whether spatial variation of fundamental constants existed during the epoch of big bang nucleosynthesis. Using existing measurements of primordial deuterium abundance we find very weak indications that such a signature might exist, but the paucity of measurements precludes any firm conclusion. We also examine existing quasar absorption spectra data that are sensitive to variation of the electron-to-proton mass ratio, mu, and x = (alpha^2 mu g_p) for spatial variation.Comment: 6 pages, 1 figur

SatCom Today in Canada: Significant Research: Overview of the Cospas-Sarsat Satellite System for Search and Rescue

Cospas-Sarsat, an international satellite system for search and rescue, started operating in 1982 and has been credited with saving thousands of lives since then. Hundreds of thousands of aviators, mariners and land users worldwide are equipped with Cospas-Sarsat distress beacons, which could help save their lives in emergency situations anywhere in the world. This paper outlines the evolution of the system and describes how satellites are constantly circling the globe monitoring for ‘SOS signals’, while tracking stations on six continents receive the satellite signals, compute the locations of the distress events and forward the calls for help to the appropriate rescue authorities. This humanitarian system is unique in the way that it is funded and operated, while its use remains free of charge to the end user in distress

Extended Hylleraas three-electron integral

A closed form expression for the three-electron Hylleraas integral involving the inverse quadratic power of one inter-particle coordinate is obtained, and recursion relations are derived for positive powers of other coordinates. This result is suited for high precision calculations of relativistic effects in lithium and light lithium-like ions.Comment: Submited to Phys. Rev.

Mobile radio propagation prediction using ray tracing methods

The basic problem is to solve the two-dimensional scalar Helmholtz equation for a point source (the antenna) situated in the vicinity of an array of scatterers (such as the houses and any other relevant objects in 1 square km of urban environment). The wavelength is a few centimeters and the houses a few metres across, so there are three disparate length scales in the problem. The question posed by BT concerned ray counting on the assumptions that: (i) rays were subject to a reflection coefficient of about 0.5 when bouncing off a house wall and (ii) that diffraction at corners reduced their energy by 90%. The quantity of particular interest was the number of rays that need to be accounted for at any particular point in order for those neglected to only contribute 10% of the field at that point; a secondary question concerned the use of rays to predict regions where the field was less than 1% of that in the region directly illuminated by the antenna. The progress made in answering these two questions is described in the next two sections and possibly useful representations of the solution of the Helmholtz equations in terms other than rays are given in the final section

Kuantitas Penggunaan Antibiotik Sebelum Dan Setelah Pembuatan Pedoman Penggunaan Antibiotik (Ppab) Penelitian Pada Kasus Bedah Digestif Rsup Dr. Kariadi Semarang

Background Pedoman Penggunaan Antibiotik (PPAB) is a book containing procedures and guides for using antibiotic properly. After the new revision, antibiotic prescription is expected to be proper with the written guidelines.Aim To measure quantity of antibiotic use in digestive cases before and after the making of PPAB.Methods This study is a prospective observational study. Subjects were patients in digestive surgery case hospitalizing in September and November. The use of antibiotic is compared between period of before and after the making of PPAB (October) using independent t test and Mann-Whitney test.Result DDD/100 patient days of antibiotic prophylaxis before the making of PPAB is 13,54 decrease to 11,96 after the making of PPAB, but the decrease is not significantly different in statistic test. The most antibiotic prophylaxis (ceftriaxone) before the making of PPAB (13,13 DDD/100 patient days) declined (11,18 DDD/100 patient days) after the making of PPAB. Quantity of antibiotic prophylaxis use of sefazolin before the making of PPAB is 0,42 DDD/patient days increase to 0,78 DD/100 patient days after the making of PPAB.Conclusion There is no significant changes of quantity of antibiotic cefazolin-ceftriaxone for prophylaxis in digestive surgical case between before and after the making of PPAB. Needed socialization, education, and trainin