Ever-stringent environmental constraints dictate that future coal cleaning technologies be compatible with micron-size particles. For super-clean coal production, the degree of liberation needed to separate coal from mineral matter, including pyrite, requires grinding to 10 mm or below. In addition, large amounts of fine coal are discharged to refuse ponds because current coal cleaning technology cannot adequately treat such finely divided materials. This research program seeks to develop an advanced coal cleaning technology uniquely suited to micron-size particles, i.e., aqueous biphase extraction. This technique relies on the ability of an aqueous system consisting of a water-soluble organic polymer and an inorganic metal salt to separate into two immiscible aqueous phases. Differences in the hydrophobic/hydrophilic properties of particulates can then be exploited to effect selective transfers to either the upper polymer-rich phase, or the lower salt-rich phase. An experimental program is proposed involving phase diagram determination, phase separation rate measurements, partition measurements, and washing experiments.

LLNL has utilized optical parametric oscillator technology to develop and field a rapidly-tunable mid-wave infrared (MWIR) DIAL system. The system can be tuned at up to 1 KHz over the 3.3-3.8 micron spectral region, where hydrogen-bond stretching modes provide spectroscopic signatures for a wide variety of chemicals. We have fielded the DIAL system on the LLNL site with targets at horizontal ranges of up to 2 km. We have collected data on noise levels and correlations and their dependences on range, turbulence, and receiver aperture size. In this paper we describe some of the implications of this data for MWIR DIAL phenomenology. In particular, the interplay of turbulence and speckle to produce the observed noise fluctuations at short ranges (<500 m) is presented.

This Site Environmental Report for Calendar Year 1996 describes the environmental monitoring programs at the Weldon Spring Site Remedial Action Project (WSSRAP). The objectives of these programs are to assess actual or potential exposure to contaminant effluents from the project area by providing public use scenarios and dose estimates, to demonstrate compliance with Federal and State permitted levels and regulations, and to summarize trends and/or changes in contaminant concentrations identified through environmental monitoring.

The polarization of a narrow, highly collimated polychromatic neutron beam is tested by a neutron spin splitter that permits the simultaneous measurement of both spin states. The device consists of a Si-Co{sub 0.11} Fe{sub 0.89} supermirror, which totally reflects one spin state up to a momentum transfer q=0.04 {angstrom}{sup -1}, whilst transmits neutrons of the opposite spin state. The supermirror is sandwitched between two thick silicon wafers and is magnetically saturated by a magnetic field of 400 Oe parallel to its surface. The neutron beam enters through the edge of one of the two silicon wavers, its spin components are split by the supermirror and exit from the opposite edges of the two silicon wafers and are recorded at different channels of a position-sensitive detector. The device is shown to have excellent efficiency over a broad range of wavelengths.