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[en] In response to the attack of the World Trade Center (WTC) on September 11, 2001, the International Union of Operating Engineers (IUOE) National Hazmat Program (OENHP) assembled and deployed a HAZMAT Emergency Management Team (Team) to the disaster site (Site). The response team consisted of a Certified Industrial Hygienist and a rotating team of industrial hygienists, safety professionals, and certified HAZMAT instructors. Through research funded by the Department of Energy (DOE) Office of Environmental Management (EM) and managed by the National Energy Technology Laboratory (NETL), the IUOE conducted human factors assessments on baseline and innovative technologies during real-world conditions and served as an advocate at the WTC disaster site to identify opportunities for the use and evaluation of DOE technologies. From this work, it is clear that opportunities exist for more DOE technologies to be made readily available for use in future emergencies
[en] An electromechanical apparatus to form Josephson junctions which is finely adjustable and is not susceptible to vibration is described. Design specifications and details of performance are given. (U.K.)
[en] Difficulties in obtaining ideal vertical vibration isolation with mechanical springs are identified as being due to the mass of the elastic element which is in turn due to its energy storage requirement. A new technique to minimize this energy is presented - being an Euler column undergoing elastic buckling. The design of a high performance vertical vibration isolation stage based on this technique is presented together with its measured performance
[en] We report on the second ever ≥3σ detection of a Ne VIII intergalactic absorption system. The system is identified in the FUSE spectrum of 3C 263 at a redshift of z = 0.32566. The presence of intermediate ionization species such as O III, O IV, N IV and C IV at the same velocity as Ne VIII, confirms that the absorption system is tracing gas at multiple ionization conditions. Unlike the intermediate ions, we find that the Ne VIII in this absorber is inconsistent with having an origin in a cool photoionization gas phase. The more likely source is collisional ionization in a warm shock-heated phase, in which case the absorber is tracing the WHIM phase of the IGM. Further constraints from H I and O IV are needed to better understand the physical conditions in the warm collisionally ionized gas. The properties of this absorber bear resemblance to the previous detection of Ne VIII reported by Savage et al.(2005).
[en] Most of the normal baryonic matter of the Universe at high and at low redshift is found in the space between galaxies. The study of this matter at low redshift has required access to ultraviolet spectroscopic space observatories. HST and FUSE have revealed that at low redshift ∼30% of the baryons reside in the cool (T∼2x104 K) photoionized IGM traced by the Lyman α forest while another ∼10-20% might exist in the warm (T∼1-9x105 K) portion of the warm-hot IGM. Evidence for the warm gas is provided by some of the O VI absorbers, the Ne VIII absorbers and very broad Lyman alpha absorbers. Understanding the physical conditions in these absorbers is important for reliably determining their baryonic content. The low z IGM is likely to play a crucial role in the evolution of the ∼8% of the baryons found in galaxies.
[en] This paper describes the design of a novel double-flexure two-axis tilt sensor with a tilt readout based on an optical walk-off sensor. The performance of the device has been investigated theoretically and experimentally. The walk-off sensor has demonstrated a sensitivity of 10-11 rad Hz-1/2 at 1 Hz. The tilt sensor has measured seismic noise ∼10-9-10-10 rad Hz-1/2 for frequency in the 2-10 Hz range
[en] We discuss the possibility of significantly reducing the number and Q-factor of violin string modes in the mirror suspension. Simulations of a bar-flexure suspension and an orthogonal ribbon have shown a reduction in the number of violin string modes when compared to a normal ribbon suspension. By calculating the expected suspension thermal noise, we find that the orthogonal ribbon provides a promising suspension alternative. A lower number of violin modes oscillating in the direction of the laser and a reduction in violin mode peak values of at least 23dB can be achieved with a slight increase in thermal noise above 40Hz
[en] Ocean waves interacting in shallow water at the shore generate land waves propagating inland. To study these waves vertical, horizontal and tilt seismic noise were measured simultaneously at one location. Vibration isolators designed for gravitational wave research were used for detection. Cross-correlation between the above components was calculated. We found correlations between all of them. However, only the correlation between horizontal and vertical motions could be addressed to land waves, and other correlations are thought to be due to local rigid body motion of the large building in which the experiments were located
[en] We report the experimental and theoretical study of electrostatically driven granular material. We show that the charged granular medium undergoes a hysteretic phase transition from the immobile condensed state (granular solid) to a fluidized dilated state (granular gas) with a changing applied electric field. In addition we observe a spontaneous precipitation of dense clusters from the gas phase and subsequent coarsening--coagulation of these clusters. Molecular dynamics simulations show qualitative agreement with experimental results. (c) 2000 The American Physical Society
[en] High frequency parametric instabilities in optical cavities are radiation pressure induced interactions between test mass mechanical modes and cavity optical modes. The parametric gain depends on the cavity power and the quality factor of the test mass internal modes (usually in ultrasonic frequency range), as well as the overlap integral for the mechanical and optical modes. In advanced laser interferometers which require high optical power and very low acoustic loss test masses, parametric instabilities could prevent interferometer operation if not suppressed. Here we review the problem of parametric instabilities in advanced detector configurations for different combinations of sapphire and fused silica test masses, and compare three methods for control or suppression of parametric instabilities-thermal tuning, surface damping and active feedback