Application of atomic magnetometry in magnetic particledetection (open access)

Application of atomic magnetometry in magnetic particledetection

We demonstrate the detection of magnetic particles carriedby water in a continuous flow using an atomic magnetic gradiometer.Studies on three types of magnetic particles are presented: a singlecobalt particle (diameter ~;150 mum, multi-domain), a suspension ofsuperparamagnetic magnetite particles (diameter ~;1 mum), andferromagnetic cobalt nanoparticles (diameter ~;10 nm, 120 kA/mmagnetization). Estimated detection limits are 20 mum diameter for asingle cobalt particle at a water flow rate 30 ml/min, 5x103 magnetiteparticles at 160 ml/min, and 50 pl for the specific ferromagnetic fluidat 130 ml/min. Possible applications of our method arediscussed.
Date: September 17, 2006
Creator: Xu, Shoujun; Donaldson, Marcus H.; Pines, Alexander; Rochester,Simon M.; Budker, Dmitry & Yashchuk, Valeriy V.
Object Type: Article
System: The UNT Digital Library
Refinery Integration of By-Products from Coal-Derived Jet Fuels (open access)

Refinery Integration of By-Products from Coal-Derived Jet Fuels

This report summarizes the accomplishments toward project goals during the second six months of the third year of the project to assess the properties and performance of coal based products. These products are in the gasoline, diesel and fuel oil range and result from coal based jet fuel production from an Air Force funded program. Specific areas of progress include generation of coal based material that has been fractionated into the desired refinery cuts and examination of carbon material, the use of a research gasoline engine to test coal-based gasoline, and modification of diesel engines for use in evaluating diesel produced in the project. At the pilot scale, the hydrotreating process was modified to separate the heavy components from the LCO and RCO fractions before hydrotreating in order to improve the performance of the catalysts in further processing. Characterization of the gasoline fuel indicates a dominance of single ring alkylcycloalkanes that have a low octane rating; however, blends containing these compounds do not have a negative effect upon gasoline when blended in refinery gasoline streams. Characterization of the diesel fuel indicates a dominance of 3-ring aromatics that have a low cetane value; however, these compounds do not have a negative …
Date: September 17, 2006
Creator: Clifford, Caroline E. Burgess; Boehman, Andre'; Song, Chunshan; Miller, Bruce & Mitchell, Gareth
Object Type: Report
System: The UNT Digital Library
The BBP Algorithm for Pi (open access)

The BBP Algorithm for Pi

The 'Bailey-Borwein-Plouffe' (BBP) algorithm for {pi} is based on the BBP formula for {pi}, which was discovered in 1995 and published in 1996 [3]: {pi} = {summation}{sub k=0}{sup {infinity}} 1/16{sup k} (4/8k+1 - 2/8k+4 - 1/8k+5 - 1/8k+6). This formula as it stands permits {pi} to be computed fairly rapidly to any given precision (although it is not as efficient for that purpose as some other formulas that are now known [4, pg. 108-112]). But its remarkable property is that it permits one to calculate (after a fairly simple manipulation) hexadecimal or binary digits of {pi} beginning at an arbitrary starting position. For example, ten hexadecimal digits {pi} beginning at position one million can be computed in only five seconds on a 2006-era personal computer. The formula itself was found by a computer program, and almost certainly constitutes the first instance of a computer program finding a significant new formula for {pi}. It turns out that the existence of this formula has implications for the long-standing unsolved question of whether {pi} is normal to commonly used number bases (a real number x is said to be b-normal if every m-long string of digits in the base-b expansion appears, in the …
Date: September 17, 2006
Creator: Bailey, David H.
Object Type: Report
System: The UNT Digital Library