In designing a multicomponent system, the use of availability as one of the criteria instead of reliability seems to be more reasonable. In this article, a method for allocating availability optimally to a multicomponent system is presented.

Fluor Hanford is responsible for cleanup of legacy wastes, old production facilities, and environmental contamination that remain at the Hanford site. New technologies and technical information are being introduced to improve cost efficiency and assure safety. This paper presents recent advances in four of Fluor's projects. Supporting the Plutonium Finishing Plant Closure Project, laboratory evaluations and thermal analyses were conducted to quantify the potential for self-heating reactions that can develop in materials used to remove plutonium from contaminated equipment. Four commercial products were tested, and safe limits for packaging these wastes have been developed. The Groundwater Remediation Project is testing two technologies that show promise of preventing groundwater contaminants from reaching the Columbia River by innovative in situ methods. Laboratory tests are showing that the mineral apatite can sequester Sr-90, and current work to control in situ placement of the barrier is supporting a field deployment in late FY 06. In another location, a new approach using zero valent iron is being tested to "mend" areas breached in the in situ redox manipulation barrier, which was installed to convert soluble chromium from the +6 to the less mobile +3 state. The Waste Stabilization and Disposition Project has successfully operated a process to grout sludge from spent fuel storage basins. An in-line sensor and a nomogram that correlates readings from the sensor to surface dose rate for drums of grouted sludge, provide the operators with a simple and effective method to assure all waste drums meet WIPP contact-handled dose rate limits. The K Basins Closure Project will be transferring sludge containing fuel fragments using hoses and several pump booster stations. Selection of equipment fabrication materials required testing with a simulant, which in turn required laboratory evaluations of irradiated fuel hardness so that an appropriate non-radioactive material could be selected. A tungsten alloy was selected and used for testing system components.

Leaf waxes are important to plant growth because they impede water loss and may influence entry of light. Leaf wax quantity and composition were studied in Capsicum annuum plants in trickle-irrigated field plots covered with white, black or red plastic mulches. The quantity of reflected blue light (BL) was greatest over white and about the same over black versus red surfaces; and reflected far-red to red ratios (FR/R) were about the same over white versus black and higher over red. The greatest quantity of total epicuticular wax developed on leaves of plants grown over white mulch (443 mu g/cm(2)) while plants grown over black and red mulches had 229 and 227 mu g/cm(2), respectively. When individual Lipid classes were expressed as percentages of the totals, esters constituted the highest percentages over white and black surfaces while secondary free fatty alcohols dominated over red. The higher ester content of epicuticular wax on plants grown over black (versus red) was almost exactly equalled by increased contents of free fatty alcohols and free fatty acids in the epicuticular wax of plants grown over red mulch. We conclude that the total wax concentration on leaves of field-grown plants was influenced by quantity of BL, and the percentage of individual components was influenced by the FR/R ratio.

Sorghum [Sorghum bicolor (L.) Moench cv RTX430, SC214, SC574, SC599, TAM428, and SC326xSC103] were grown on soils of pH 4.2 or 6.2-6.5. Leaf and nonexserted juvenile panicle tissues were collected at 75 days after planting. Fresh and dry weights were measured and element contents [sulfur (S), phosphorus (Pi, magnesium (Mg), calcium (Ca), potassium (K), zinc (Zn), iron (Fe), and copper (Cu)] were measured by atomic absorption. Significant cultivar differences in ion concentration (mu mol/g dry weight) were found. Juvenile panicles had higher ion concentration (mu mol/g dry weight) [S, P, Mg, Ca, K, Zn, and Cu) than leaves. Within leaf tissue, ion concentration (mu mol/g dry weight) was correlated with tissue water content (g water/g dry weight).

Seedling sorghum [Sorghum bicolor (L.) Moench. cv GP-10, SC283, SC574, and Funk G522DR] primary root tips (1-cm) content of calcium (Ca), phosphorus (P), zinc (Zn), boron (B), manganese (Mn), iron (Fe), magnesium (Mg), and copper (Cu) in response to a Ca2+-channel blocker (nifedipine 0, 0.01, 0.1, or 1 mu M) was measured after a 1-hr exposure to Hoagland and Amen complete mineral nutrient solution. Content of ions was significantly different among the cultivars. Responses to nifedipine were element-cultivar-blocker concentration dependent.

Erythrosine B (EB), a specific inhibitor of calcium (Ca2+)-dependent Mg2+-ATPase in plasma membranes, was evaluated for influence on (Ca2+)-Ca-45 uptake by 1 cm root tips from seedlings of four sorghum [Sorghum bicolor (L.) Moench cv Funk G522DR, GP-10, SC574, SC283) cultivars. Erythrosine B (0.01 muM) inhibited (Ca2+)-Ca-45 uptake 33% in SC574 and GP-10; but higher concentrations (1 muM) were required to produce equivalent (Ca2+)-Ca-45 uptake inhibitions in SC283 and Fund G522DR.

SITS (1 m M ), a Cl − channel blocker, significantly decreased [ 14 C]UL-cyproconazole absorption in sorghum ( Sorghum bicolor (L.) Moench. cv Funk G522DR) seedling roots and shoots. DIDS (0.1 m M ), a Cl − channel blocker, significantly decreased [ 14 C]UL-cyproconazole absorption in Funk G522DR roots. Neither PCMBS (1 m M ), an H + -ATPase and Ca 2+ -ATPase inactivator, nor nifedipine (1 μ M ), a Ca 2+ channel blocker, significantly decreased [ 14 C]UL-cyproconazole absorption in shoots of four sorghum cultivars (i.e., Funk G522DR, SC574, SC283, and GP-10) but PCMBS did induce a minor inhibition of [ 14 C]UL-cyproconazole absorption in roots of the GP-10 cultivar.

Sorghum [Sorghum bicolor (L.) Moench] cultivars were planted in 8 cm x 8 cm x 8 cm pots filled with 'white quartz flintshot' sand containing 0, 0.25, 0.50, 1.0, or 2.0 mg/kg metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2 methoxy-1-methylethyl)acetamide] and the pots were watered on alternate days with 100 mL 0.1 M sodium acetate at pH 6.0, 5.5, 5.0, 4.5, or 4.0 to determine the influence of excess H+ and metolachlor concentrations on sorghum root growth. Cultivars utilized were Funk G522DR, SC574, SC283, GP-10, 58M, and 38M. At pH 4.5 and 4.0 (0 metolachlor), root lengths of Funk G522DR and SC574 were significantly decreased compared to roots from plants grown at pH 6.0. The other four cultivars had decreased root growth at pH 4.0 (0 metolachlor). Metolachlor influence on sorghum cultivar root growth was dependent on pH, cultivar, and metolachlor concentration. None of the cultivars showed increased metolachlor activity which was influenced by pH. Metolachlor (0.25 mg/kg) reversed the influence of excess H+ concentration (pH 4.0) in SC574. Metolachlor (0.5, 1.0, and 2.0 ppmw) reversed the excess H+ concentration inhibition of root growth at pH 4.0 in Funk G522DR.

A direct comparison was carried out of the biological effectiveness of protons and alpha-particles of the same linear energy transfer (LET) under identical conditions with a variety of in vitro biological systems. Monolayers of mammalian cells were irradiated with accelerated beams of protons (1.2 and 1.4 MeV) and alpha-particles (30 and 35 MeV) corresponding to LETs of 23 and 20 keV microns-1 for each particle type. For V79-4 cells it was observed that the linear term of the dose-response for cell inactivation by protons was significantly greater than that for alpha-particles of the same LET. For HeLa and HeLa S3 cells, also, the linear term appeared to be greater for protons, but this was not observed with more limited data for C3H 10T1/2 cells. The result for V79 cells is in agreement with the report of Belli et al. (1989) who observed that the biological effectiveness of protons rose sharply between 17 and 30 keV microns-1 in strong contrast to alpha-particles which reached a peak effectiveness at greater than 100 keV microns-1. These results place new constraints on the biologically relevant features of the microscopic structure of radiation tracks, and have implications for the mechanistic and practical comparison between radiations.

Shoot length (cm), shoot fresh weight (g/pot), root length (cm), and root fresh weight (g/pot) were measured on six cultivars of wheat (Triticum aestivum L. cv Saluda, C9733, Gore, Stacy, FL301, and FL302) grown at pH 6.0, 5.5, 5.0, 4.5, or 4.0 for 14 days in ‘white quartz flintshot’ sand. Plants were watered on alternate days with pH-adjusted buffer solutions. All measured plant parameters decreased as H+ concentration increased from pH 6.0 to 4.0. Decreased lengths of shoots and roots were similar among the cultivars as the pH decreased. This indicated a uniform response of wheat cultivars to excess H+ concentration in the soil solution; however, the decrease in shoot and root length was only about 50% as large as was previously reported for sorghum [Sorghum bicolor (L.) Moench.].

A versatile irradiator has been constructed for in vitro irradiation of mammalian cells with alpha-particles of well-defined energy, LET, direction, dose and dose rate. It is based on approximately 1.2 x 10(9) Bq of 238Pu (on a platinum disc) contained in a He-filled chamber. In a standard configuration, monolayers of cells grown in 10 Hostaphan-based dishes are irradiated with 3.26 +/- 0.22 MeV alpha-particles (LET 121 keV microns-1) at selectable dose rates from approximately 2 Gy min-1 down to less than 10(-4) Gy min-1 (i.e. fluence rates of 1 x 10(7) cm-2 min-1 to 3 x 10(2) cm-2 min-1). Single dishes can be irradiated at dose rates up to 24 Gy min-1 (fluence rate 1 x 10(8) cm-2 min-1). Incident energy and LET can be varied from 0.8 to 4.2 MeV and 266 to 102 keV microns-1, respectively. The irradiator has full incubation and gassing facilities for protracted irradiations. The irradiator is particularly suitable for in vitro analytical studies of the biological effects of alpha-particles of energies and LETs similar to those which cells may receive in vivo from radionuclides such as radon and the actinides. It has been used successfully for investigations of a variety of alpha-particle-induced effects in different cell types irradiated either as attached monolayers or as very thin suspensions.

Evaluations of the influence of EPTC on mineral ion root uptake and translocation to the foliage were undertaken. Root uptake was measured in wheat (Triticum aestivum L. cv Holley) was grown in 0.5 Hoagland complete mineral nutrient solution. Timed (< 4h) accumulation studies were undertaken in the presence of: a) p-chloromercuribenzenesulfonic acid (PCMBS) which does not penetrate through membranes but does inhibit sulfhydryl groups (SH), and b) dithiothreitol (DTT) which is membrane permeable and protects SH from PCMBS. Mg, Ca, K, Fe, and Mn accumulations were decreased by PCMBS and the partial inhibition was reversed by DTT. Calcium root accumulation data were explicable as two modes of Ca entry into roots and one involved a SH containing enzyme.Ion translocation to the foliage was evaluated in nutrient solutions containing sub-lethal concentrations of S-ethyldipropylthiocarbamate (EPTC) (0, 0.625, 0.125, 0.25, or 0.5 mg/L), EPTC did not act as a general sulfhydryl group inhibitor. Shoot dry weight per pot decreased as EPTC concentration increased. Total water utilization (mL/pot) decreased and transpiration (mLg DW) increased as EPTC concentration increased. Stomatal aperture (mu) increased as EPTC concentration increased. Water use (ml/pot) was linearly correlated with dry weight (mg/pot). Shoot total ion contents (i.e., P, K, Ca, Mg, and Cu) decreased as EPTC concentration increased and absorption and translocation of P, Ca, Mg, and Cu ions were correlated to total water utilization or transpiration [mL/g DW]. Thus, the altered concentration of these ions in EPTC-treated wheat shoots is explicable as the results of an influence by EPTC on stomatal physiology.

Twenty-eight day old wheat (Triticum aestivum L. cv Stacy) response to varying Mn concentration (10.1-10,000 micromolar) in nutrient solution was measured. Manganese concentrations in the most recently matured leaves (blade 1) were 0.21 to 19.03 mmol Mn per kilogram dry weight, respectively. Fresh and dry weights increased to a maximum at the 5 micromolar Mn nutritional level (0.37 millimole Mn per kilogram dry weight) and were decreased at Mn above and below this concentration. Blade 1 chloroplast pigment concentrations increased up to the 20 micromolar Mn nutritional level (1.98 millimole Mn per kilogram dry weight) and decreased at higher Mn concentrations. Thylakoid Mn content was above 1 mole Mn/100 mole chloroplast at Mn nutrition levels which resulted in greatly decreased plant growth. Total phytoene biosynthesis was decreased by Mn deficiency and toxicity. In vitro ent- kaurene synthesis was greatly influenced by Mn concentration with a maximal biosynthesis at 1 micromolar Mn and decreases at Mn levels above and below this concentration. In vivo blade 1 gibberellic acid equivalent concentrations were maximal at 20 parts per million Mn nutrition solution levels (1.98 millimole Mn per kilogram dry weight) and decreased at Mn tissue concentrations above and below this value; additionally, gibberellic acid concentrations were reciprocal to extracted C(20) alcohol concentrations. Mn influence on gibberellin and chloroplast pigment biosyntheses exactly matched the measured changes in growth.

V79 hamster cells in plateau (extended G1) phase were irradiated with either 250 kV ('hard') X-rays or carbon K characteristic ultrasoft X-rays under conditions minimizing cell overlap. These cells were killed most effectively by the carbon X-rays, by a factor of about 3 relative to hard X-rays, in agreement with our previous findings with cells in exponential growth. Chromosome-type aberrations were measured at 3 fixation times within the first division cycle after irradiation, and an approximately uniform sensitivity to aberration induction was found for both radiations. The combined aberration data show that carbon X-rays are 2 or more times as effective as hard X-rays, depending on dose and/or data fit. Exchange aberrations require recombination between two separate chromosomes, but they are induced efficiently by carbon X-rays with a substantial linear component to the dose-response despite the very short electron tracks (approximately less than 7 nm) that they produce in the cell. This implies either that the participating DNA helices must be lying extremely close together at the time of radiation damage, so that one track can effectively damage both helices, or that only one radiation-damaged chromosome is needed to promote an exchange event.

Induction of DNA double-strand breaks in diploid wild-type yeast cells, and inactivation of diploid mutant cells (rad54-3) unable to repair DNA double-strand breaks, were studied with aluminium K (1.5 keV) and carbon K (0.278 keV) characteristic X-rays. The induction of DNA double-strand breaks was found to increase linearly with absorbed dose for both characteristic X-rays. Carbon K X-rays were more effective than aluminium K X-rays. Relative to 60Co gamma-rays the r.b.e.-values for the induction of DNA double-strand breaks were found to be 3.8 and 2.2 for carbon K and aluminium K X-rays respectively. The survival curves of the rad54-3 mutant cells were exponential for both ultrasoft X-rays. For inactivation of rad54-3 mutant cells, the r.b.e.-values relative to 60Co gamma-rays were 2.6 and 2.4 for carbon K and aluminium K X-rays, respectively. The DNA double-strand break data obtained with aluminium K and carbon K X-rays are in agreement with the data obtained for gene mutation, chromosome aberrations and inactivation of mammalian cells, suggesting that DNA double-strand breaks are the possible molecular lesions leading to these effects.