Adsorption of RDX and HMX in Rapid Small-Scale Column Tests: Implications for Full-Scale Adsorbers

The high explosive (HE) compounds royal demolition explosive or hexahydro-1,3,5-trinitro-1,3,5-triazocine (RDX) and high melting explosive or octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) have been detected as groundwater contaminants at many military facilities. This research evaluated adsorption of RDX and HMX with granular activated carbon (GAC) to provide guidance for the design and operation of GAC adsorbers for treatment of HE-contaminated groundwater. Five GACs were screened using rapid small-scale column tests (RSSCTs), after which additional tests were performed with the two GACs that most effectively treated mixtures of RDX and HMX (Calgon F400 and Northwestern LB-830). GAC service life as a function of empty-bed contact time (EBCT) was determined using RSSCTs for a range of simulated full scale EBCTs with influent concentrations of 2,200 μg RDX/L and 350 μg HMX/L. Increasing the influent concentration of either contaminant significantly reduced the predicted service life, as did preloading GAC with groundwater natural organic matter. In batch isotherm tests, RDX was less adsorbable than HMX under all conditions studied. Concurrent loading of natural organic matter reduced the Freundlich K for RDX, whereas adsorption of HMX was not affected. Of the GACs tested, Calgon F400 most effectively removed RDX and HMX.     

Liquefaction of coal using supercritical fluid mixtures

Powhatan No. 5 and Bruceton coals were liquefied for 15–60 min at 653 K and 30 MPa in supercritical aqueous mixtures containing 10–20 wt% tetrahydroquinoline (THQ), quinoline or tetralin. The THQ-water mixtures produced the highest conversion to tetrahydrofuran (THF) soluble products (up to 74%). Tetralin-water, quinoline-water and pure water solvents gave increasingly lower yields of THF solubles. Addition of hydrogen to the quinoline-water solvent mixture increased yields slightly, but not to the level obtained using the THQ-water mixture.The yields of THF solubles in all instances depended upon the concentration of solvent in the mixture, with the 10 wt% THQ and 10 wt% tetralin (in water) giving higher yields than either 0 or 20 wt% concentrations. The nitrogen-containing solvents were chemically bonded to the THF-soluble product, as observed by g.p.c.     

Oxygen Fugacity Control in Nonflowing Atmospheres: I, Experimental Observations in CO/CO2 and O2/N2 Mixtures

The performance of a stabilized zirconia sensor and electrochemical oxygen pump combination in the isothermal control of oxygen fugacity in a nonflowing atmosphere was studied in a closed furnace system in the temperature range of 800° to 1100°C. Under certain conditions, large differences in oxygen pressure were found between sensors at the same constant temperature in close proximity to each other. This result reflected the existence of a stable steplike oxygen fugacity "front" in the furnace, separating regions which differed by several orders of magnitude in oxygen fugacity. This oxygen pressure profile in the furnace resulted from the steady-state transport of oxygen from oxygen leakage sources to the pump. The existence, magnitude, and position of the oxygen fugacity front were found to depend on the gas-phase composition, the relative locations of the leakage sources and the pump, the oxygen fugacity of the reference electrode, and the magnitude of the oxygen flux in the gas phase.     

Associations between apolipoprotein E genotype and circulating F<Subscript>2</Subscript>-isoprostane levels in humans

Apolipoprotein E (apoE), an important determinant of plasma lipoprotein metabolism, has three common alleles (ε2, ε3, and ε4). Population studies have shown that the risk of diseases characterized by oxidative damage, such as coronary heart disease and Alzheimer’s disease, is significantly higher in ɛ4 carriers. We evaluated the association between apoE genotypes and plasma F₂-isoprostane levels, an index of lipid peroxidation, in humans. Two hundred seventy-four healthy subjects (104 males, 170 females; 46.9±13.0 yr; 200 whites, 74 blacks; 81 nonsmokers, 64 passive smokers, and 129 active smokers) recruited for a randomized clinical antioxidant intervention trial were included in this analysis. ApoE genotype was determined by PCR and restriction enzyme digestion. Free plasma F₂-isoprostane was measured by GC-MS. Genotype groups were compared using multiple regression analysis with adjustment for sex, age, race, smoking status, body mass index, plasma ascorbic acid, and β-carotene. Subjects with ε3/ε4 and ε4/ε4 genotype (ε4-carriers) and with ε2/ε3 and ε3/ε3 (non-ε4-carriers) were pooled for analysis. In subjects with high cholesterol levels (total cholesterol above 200 mg/dl), plasma F₂-isoprostane levels were 29% higher in ε4 carriers than in non-ε4-carriers (P=0.0056). High-cholesterol subjects that are ε4 carriers have significantly higher levels of lipid peroxidation as assessed by circulating F₂-isoprostane levels.     

Enantiospecific Synthesis and Cytotoxicity Evaluation of Oximidine II Analogues

Analogues of the anticancer natural product oximidine II were prepared and evaluated for cytotoxicity. One analogue of oximidine II that carries a C15 allylic amide side chain as well as two analogues with C15 vinyl sulfone side chains were found to lack cytotoxicity against the cancer cell line SK‐Mel‐5, thereby confirming the necessity of the C15 enamide side chain of oximidine II for cytotoxicity. Four analogues, designed by comparative molecular similarity index analysis (CoMSIA), that feature a less complex macrolactone scaffold were prepared and tested. The two analogues carrying a C15 vinyl sulfone group and the two analogues with a C15 oximidine II enamide side chain showed weak cytotoxicity against the SK‐Mel‐5 cell line and other cell lines, indicating that the designed simplified macrocycles cannot replace the oximidine II macrocycle.     

Bubble-Rise Velocity in AC and DC Electrofluidized Beds

The behavior of a single injected bubble in a rectangular air-fluidized bed of glass microspheres has been studied experimentally for the ac and dc applied electric field cases. An empirical dimensionless equation for bubble-rise velocity and bubble volume is reviewed for application below a critical ac electric field strength for significant electromechanical effects. As observed previously, dc experiments in electrofluidized beds are more sensitive to time dependence and to hysteresis effects than are ac experiments, as densely spaced particles tend to become immobilized in the presence of dc electric fields.     

Asymmetric synthesis and biological activity of nor-α-tocopherol, a new vitamin E analogue

The vitamin E analogues (2R,4′R,8′R)‐nor‐α‐tocopherol (94 % de) and (2RS,4′R,8′R)‐nor‐α‐tocopherol have been synthesized from (all R)‐hexahydrofarnesol and phytol, respectively. According to in vitro experiments with murine macrophages nor‐α‐tocopherol is an anti‐inflammatory compound more potent than α‐tocopherol.