[en] A micro-molding process was used to fabricate parts in the 0.1 to 10 mm size range from a stainless steel nano-powder. The two types of molds used were both produced from parts fabricated using the LIGA process so that they had precise dimensional tolerance and straight sidewalls. Rigid PMMA molds were made by injection molding and flexible silicone rubber molds were made by casting. Mold filling was accomplished by mixing the powder with epoxy to form a putty-like material that was then pressed into the mold cavities and allowed to cure. After pyrolysis of the epoxy, the parts were sintered in forming gas. The densification kinetics were measured in situ using a video system. Full densification was achieved after 1 hour at 1350 C. The microstructure of the sintered parts was examined using the SEM. The hardness, dimensional tolerance and surface roughness of the sintered parts were also measured

[en] The theoretical basis of, and practical experience in, legal liability in the clinical practice of radiation oncology is reviewed, with a view to developing suggestions to help practitioners limit their exposure to liability. New information regarding the number, size, and legal theories of litigation against radiation oncologists is presented. The most common legal bases of liability are then explored in greater detail, including 'malpractice', and informed consent, with suggestions of improving the specialty's record of documenting informed consent. Collateral consequences of suffering a malpractice claim (i.e., the National Practitioner Data Bank) will also be briefly discussed

[en] The use of oxidized metal powders in mechanical shock or crush safety enhancers in nuclear weapons has been investigated. The functioning of these devices is based on the remarkable electrical behavior of compacts of certain oxidized metal powders when subjected to compressive stress. For example, the low voltage resistivity of a compact of oxidized tantalum powder was found to decrease by over six orders of magnitude during compaction between 1 MPa, where the thin, insulating oxide coatings on the particles are intact, to 10 MPa, where the oxide coatings have broken down along a chain of particles spanning the electrodes. In this work, the behavior of tantalum and aluminum powders was investigated. The low voltage resistivity during compaction of powders oxidized under various conditions was measured and compared. In addition, the resistivity at higher voltages and the dielectric breakdown strength during compaction were also measured. A key finding was that significant changes in the electrical properties persist after the removal of the stress so that a mechanical shock enhancer is feasible. This was verified by preliminary shock experiments. Finally, conceptual designs for both types of enhancers are presented

[en] Ethical issues arise when a professional endeavor such as medicine, which seeks to place the well-being of others over the self-interest of the practitioner, meets granular business and legal decisions involved in making a livelihood out of a professional calling. The use of restrictive covenants, involvement in self-referral patterns, and maintaining appropriate comity among physicians while engaged in the marketplace are common challenges in radiation oncology practice. A paradigm of analysis is presented to help navigate these management challenges.

[en] Pellet fueling experiments on Alcator C focused on the regime of improved energy and particle confinement, where it was observed that transport for the ionic species was reasonably well described by neo-classical theory. Ion energy transport dropped and particle confinement, particularly for impurity species increased dramatically. These effects have been ascribed to the suppression of ion temperature gradient driven modes (/eta//sub i/) by the peaked density profile set up by pellet injection. Although radiation by high Z ions was unimportant in these discharges, the accumulation of low Z impurities, principally carbon, had a profound effect on the discharge by peaking the resistivity profile and reducing the current density near the plasma center. One result of this was a modification of sawtooth activity; a lengthening of the period between sawteeth and ultimately their complete suppression. After suppression of the sawteeth, very large amplitude m = 1, n = 1 oscillations were often observed. The appearance of this mode was often correlated with saturation of impurity confinement. We speculate that this mode is a form of the m = 1 ideal mode that has been held responsible for the sawtooth crash. 14 refs., 5 figs

[en] The safe handling of reprocessed fuel addresses several scientific goals, especially when considering the capture and long-term storage of volatile radionuclides that are necessary during this process. Despite not being a major component of the off-gas, radioiodine (I₂) is particularly challenging, because it is a highly mobile gas and ¹²⁹I is a long-lived radionuclide (1.57 x 10⁷ years). Therefore, its capture and sequestration is of great interest on a societal level. Herein, we explore novel routes toward the effective capture and storage of iodine. In particular, we report on the novel use of a new class of porous solid-state functional materials (metal-organic frameworks, MOFs), as high-capacity adsorbents of molecular iodine. We further describe the formation of novel glass-composite material (GCM) waste forms from the mixing and sintering of the I₂-containing MOFs with Bi-Zn-O low-temperature sintering glasses and silver metal flakes. Our findings indicate that, upon sintering, a uniform monolith is formed, with no evidence of iodine loss; iodine is sequestered during the heating process by the in situ formation of AgI. Detailed materials characterization analysis is presented for the GCMs. This includes powder X-ray diffraction, scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), thermal analysis (thermogravimetric analysis (TGA)), and chemical durability tests including aqueous leach studies (product consistency test (PCT)), with X-ray fluorescence (XRF) and inductively coupled plasma-mass spectrometry (ICP-MS) of the PCT leachate.

[en] The declining involvement of oil and gas operators in research and development (R and D) is reducing profits for both the operator and the service provider. Greater responsibility for technology development is now being shouldered by the service providers, and there is a growing concern that they are drilling themselves out of a job. This concern is compounded when the financial results of the operator are compared with those of the service provider. The paper discusses reduced profitability, misconceptions about new technologies, time-based incentives, risk and reward, the aligned-interest agreement, and agreement structuring

[en] Five 7 mm diameter remote-head visible charge-coupled device (CCD) cameras are being used on Alcator C-Mod for several different diagnostic purposes. All of the cameras' detectors and optics are placed inside a magnetic field of up to 4 T. Images of the cameras are recorded simultaneously using two three-channel color framegrabber cards. Two CCD cameras are used typically to generate two-dimensional emissivity profiles of deuterium line radiation from the divertor. Interference filters are used to select the spectral line to be measured. The local emissivity is obtained by inverting the measured brightnesses assuming toroidal symmetry of the emission. Another use of the cameras is the identification and localization of impurity sources generated by the ion cyclotron radio frequency (ICRF) antennas, which supply the auxiliary heating on Alcator C-Mod. The impurities generated by the antennas are identified by correlating in time the injections seen at the cameras with measurements made with core diagnostics. Fibers whose views aligned with the camera views and whose outputs are coupled to a visible spectrometer are also used to identify the species of the impurities injected

[en] This paper reports on the experimental characterization of the poloidal and radial propagation of turbulent structures in the scrape-off layer of the Alcator C-Mod tokamak. Turbulent structures are tracked using turbulence imaging diagnostics, which views the Da emission of a localized gas puff in a poloidal cross section of the scrape-off layer with an ultra fast camera system. Large-amplitude turbulent structures are extracted from the small-amplitude background fluctuations and their velocity is extracted by two-dimensional cross-correlation technique. It is demonstrated that the poloidal velocity is mainly with background E B plasma rotation. Radial velocities of structures are found to lie in the range % of the ion sound speed, thereby causing large radial transport events. (Author)

[en] An infrared imaging system, based on an Amber Radiance 1 infrared camera, is used at Alcator C-Mod to measure the surface temperatures in the lower divertor region. Due to the supra-linear dependence of the thermal radiation with temperature it is important to make use of the 12-bit digitization of the focal plane array of the Amber camera and not be limited by the 8 bits inherent to the video signal. It is also necessary for the image capture device (i.e., fast computer) to be removed from the high magnetic field environment surrounding the experiment. Finally, the coupling between the digital camera output and the capture device should be nonconductive for isolation purposes (i.e., optical coupling). A digital video remote camera interface (RCI) coupled to a PCI bus fiber optic interface board is used to accomplish this task. Using this PCI-RCI system, the 60 Hz images from the Amber Radiance 1 camera, each composed of 256x256 pixels and 12 bits/pixel, are captured by a Windows NT computer. An electrical trigger signal is given directly to the RCI module to synchronize the image stream with the experiment. The RCI can be programmed from the host computer to work with a variety of digital cameras, including the Amber Radiance 1 camera