[en] The limiting bubble wall velocity during a first-order electroweak phase transition is of interest in scenarios for electroweak baryogenesis. Khlebnikov has recently proposed an interesting method for computing this velocity based on the fluctuation-dissipation theorem. It is demonstrated that at one-loop order this method is identical to simple, earlier techniques for computing the wall velocity based on computing the friction from particles reflecting off or transmitting through the wall in the ideal gas limit

[en] This slide show documents waste disposal at the Nevada National Security Site. Topics covered include: radionuclide requirements for waste disposal; approved performance assessment (PA) for depleted uranium disposal; requirements; program approval; the Waste Acceptance Review Panel (WARP); description of the Radioactive Waste Acceptance Program (RWAP); facility evaluation; recent program accomplishments, nuclear facility safety changes; higher-activity waste stream disposal; and, large volume bulk waste streams

No abstract available

[en] This paper describes the activities required to modify a facility and the process of characterizing, repackaging, and preparing for shipment the Nevada Test Site's (NTS) legacy transuranic (TRU) waste in 58 oversize boxes (OSB). The waste, generated at other U.S. Department of Energy (DOE) sites and shipped to the NTS between 1974 and 1990, requires size-reduction for off-site shipment and disposal. The waste processing approach was tailored to reduce the volume of TRU waste by employing decontamination and non-destructive assay. As a result, the low-level waste (LLW) generated by this process was packaged, with minimal size reduction, in large sea-land containers for disposal at the NTS Area 5 Radioactive Waste Management Complex (RWMC). The remaining TRU waste was repackaged and sent to the Idaho National Laboratory Consolidation Site for additional characterization in preparation for disposal at the Waste Isolation Pilot Plant (WIPP), near Carlsbad, New Mexico. The DOE National Nuclear Security Administration Nevada Site Office and the NTS Management and Operating (M and O) contractor, NSTec, successfully partnered to modify and upgrade an existing facility, the Visual Examination and Repackaging Building (VERB). The VERB modifications, including a new ventilation system and modified containment structure, required an approved Preliminary Documented Safety Analysis prior to project procurement and construction. Upgrade of the VERB from a radiological facility to a Hazard Category 3 Nuclear Facility required new rigor in the design and construction areas and was executed on an aggressive schedule. The facility Documented Safety Analysis required that OSBs be vented prior to introduction into the VERB. Box venting was safely completed after developing and implementing two types of custom venting systems for the heavy gauge box construction. A remotely operated punching process was used on boxes with wall thickness of up to 3.05 mm (0.120 in) to insert aluminum bronze filters and sample ports to prevent sparking during penetration. A remotely operated cold-drilling process with self-drilling, self-tapping titanium coated spark-resistant filters was used for boxes with wall thickness of up to 6.35 mm (0.25 in). The box headspace was sampled for the presence of flammable gases. To further accelerate the project schedule, an innovative treatment process was used. Several of the OSBs were re-assayed and determined to be mixed low-level waste (MLLW) which allowed treatment, followed by disposal in the Mixed Waste Disposal Unit at the NTS Area 5 Radioactive Waste Management Complex (RWMC). The MLLW boxes were certified using real-time radiography and overpacked into custom-built polyethylene-lined macroencapsulation containers. The polyethylene-lined lid was welded to the poly-lined box using automatically controlled resistance heating through embedded wiring in the lid. The work was performed under the existing Documented Safety Analysis since plastic welding is accomplished at low temperature and does not introduce the risks of other macroencapsulation processes, such as welding stainless steel containers. The macroencapsulation process for MLLW not only accelerated the schedule by reducing the number of boxes requiring size reduction, but it also resulted in significantly improved safety with as low as reasonable achievable levels of exposure to workers plus reduced cost by eliminating the need to perform repackaging in the VERB

No abstract available

[en] In 1972 Beckman and co-workers reported the successful use of ruby laser transscleral cyclocoagulation to lower intraocular pressure. The recent advent of commercial neodymium:YAG lasers has made available a new source of pulsed laser energy that combines high energy with good scleral tissue penetrance. The authors tested whether such a laser could be used to accomplish transscleral cyclocoagulation in rabbits and to determine what energy level would be required to cause a sustained reduction of intraocular pressure. (Auth.)

[en] The determination of the optimum-cost utilisation of given available sources is a partial problem in planning extensions. The author describes a simulation program which approximates to actual practice and which makes it possible to take into account accurately the multifarious boundary conditions arising from the connections of an electricity supply undertaking. A theoretically exact optimising model was not aimed at, with its solutions. A short account is given of special problems in load forecasting which are involved in the simulation program. (orig.)

[en] A high resolution neutron diffractometer which was installed at the 4 MW reactor in Garching is described. The thermal flux of the reactor is 10¹³ n/cm²sec and the resolution of the instrumental is Δd/d approximately equal to 10^-3. It is based on the time-of-flight method which was originally demonstrated by Buras (1963) and co-workers. One measures the wavelength of neutrons scattered by the sample into a fixed direction out of a pulsed white beam

[en] It has recently been argued that the rate per unit volume of baryon number violation (topological transitions) in the hot, symmetric phase of electroweak theory is of the form ηα_w⁵T⁴ in the weak-coupling limit, where η is a nonperturbative numerical coefficient. Over the past several years, there have been attempts to extract the rate of baryon number violation from real-time simulations of classical thermal field theory on a spatial lattice. Unfortunately, the coefficient η will not be the same for classical lattice theories and the real quantum theory. However, by analyzing the appropriate effective theory on the lattice using the method of hard thermal loops, I show that the only obstruction to precisely relating the rates in the real and lattice theories is the fact that the long-distance physics on the lattice is not rotationally invariant. (This is unlike Euclidean-time measurements, where rotational invariance is always recovered in the continuum limit.) I then propose how this violation of rotational invariance can be eliminated emdash and the real B violation rate measured emdash by choosing an appropriate lattice Hamiltonian. I also propose a rough measure of the systematic error to be expected from using simpler, unimproved Hamiltonians. As a byproduct of my investigation, the plasma frequency and Debye mass are computed for classical thermal field theory on the lattice. copyright 1997 The American Physical Society

[en] The issue of sphaleron-induced baryon decay and various paradoxes related to the instanton method of computation are addressed. By various examples we argue that there is no contradiction between the instanton estimates and sphaleron estimates, and argue that for electroweak theory these estimates correspond to different approximations for distinct phenomena. We also investigate numerically the nature of the classical decay of a sphaleron in the (1+1)-dimensional Abelian Higgs model