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Molar Basis (molar + basis)
Selected AbstractsComparison of the Heavy Metal Biosorption Capacity of Active, Heat-Inactivated and NaOH-Treated Phanerochaete chrysosporium BiosorbentsENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 1 2004E. Güri Abstract Three different kinds of Phanerochaete chrysosporium (NaOH-treated, heat-inactivated and active) biosorbent were used for the removal of Cd(II) and Hg(II) ions from aquatic systems. The biosorption of Cd(II) and Hg(II) ions on three different forms of Phanerochaete chrysosporium was studied in aqueous solutions in the concentration range of 50,700 mg/L. Maximum biosorption capacities of NaOH-treated, heat-inactivated and active Phanerochaete chrysosporium biomass were found to be 148.37,mg/g, 78.68,mg/g and 68.56,mg/g for Cd(II) as well as 224.67,mg/g, 122.37,mg/g and 88.26,mg/g for Hg(II), respectively. For Cd(II) and Hg(II) ions, the order of affinity of the biosorbents was arranged as NaOH-treated,> heat-inactivated,>,active. The order of the amount of metal ions adsorbed was established as Hg(II),>,Cd(II) on a weight basis, and as Cd(II),>,Hg(II) on a molar basis. Biosorption equilibriums were established in about 60,min. The effect of the pH was also investigated, and maximum rates of biosorption of metal ions on the three different forms of Phanerochaete chrysosporium were observed at pH,6.0. The reusability experiments and synthetic wastewater studies were carried out with the most effective form, i.e., the NaOH-treated Phanerochaete chrysosporium biomass. It was observed that the biosorbent could be regenerated using 10,mM HCl solution, with a recovery of up to 98%, and it could be reused in five biosorption-desorption cycles without any considerable loss in biosorption capacity. The alkali-treated Phanerochaete chrysosporium removed 73% of Cd(II) and 81% of Hg(II) ions from synthetic wastewater. [source] Untersuchungen an wachsenden Schweinen zum Futterwert einer neuen Ackerbohnensorte (Vicia faba L.) bei Ergänzung mit DL -Methionin oder DL -Methionin-HydroxyanalogJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1-2 2002HJ. ABEL Investigations in growing pigs on the feeding value of a new cultivar of field beans (Vicia faba L.) supplemented with DL -methionine or DL -methionine-hydroxyanalogue A basal control mixture of barley, soy bean meal and soy bean oil was replaced by 25% of the new field bean-cultivar `Divine' and the resulting two mixtures were supplemented with minerals, trace elements, vitamins and amino acids according to the ideal protein concept. The control diet was adjusted with DL -methionine (DL -Met), the field bean mixture either with DL -Met or DL -methionine-hydroxyanalogue (DL -MHA) assuming biological equivalence on a molar basis for both supplements. The three experimental diets were fed to growing pigs (35,40 kg bwt.). Spontaneous urine samples were analysed separately for determining parameters that characterize the acid-base status of the pigs. There were no significant differences between experimental groups in nutrient digestibilities. The level of bacterially fermentable substances was increased in the diets containing field beans. The field beans contained 14 mg ME/kg DM. There were no significant (p < 0,05) differences in N- and mineral-retentions (Ca, P, Na, K) between the treatments. The stronger alkalinity found in urine after feeding the field bean mixtures resulted from a higher electrolyte balance of the diet. Eine Kontrollration aus Gerste, Sojaschrot und Sojaöl wurde zu 25% durch Ackerbohnen der neugezüchteten Sorte `Divine' ersetzt und beide Mischungen mit Mineral- und Wirkstoffen sowie Aminosäuren ergänzt. Die Ergänzung mit Methionin erfolgte in der Kontrollmischung mit DL -Methionin, in der Ackerbohnenmischung mit DL -Methionin (DL -Met) oder DL -Methionin-Hydroxyanalog (DL -MHA) unter Zugrundelegung der molaren Wirkungsäquivalenz der beiden Supplemente. Die resultierenden drei Futtermischungen wurden in Stoffwechselversuchen an Schweine (35,40 kg LM) gefüttert. Separate Spontanharnproben wurden auf Parameter des Säure-Basen-Haushalts der Tiere untersucht. Zwischen den Versuchsgruppen traten keine signifikanten Unterschiede in den Nährstoffverdaulichkeiten auf. Die Gehalte an bakteriell fermentierbarer Substanz wurden durch Ackerbohnen erhöht. Der Gehalt der Ackerbohnen an umsetzbarer Energie lag bei 14 MJ ME/kg T. Die N- und Mineralstoffretentionen (Ca, P, Na, K) der Schweine unterschieden sich zwischen den Fütterungsgruppen nicht signifikant (p < 0,05). Die bei Ackerbohnenfütterung gesteigerte Harn-Alkalität ließ sich auf erhöhte kaliumbedingte Elektrolytbilanzen des Futters zurückführen. [source] A Hypothesis for the Chemical Basis for Perception of Sour TasteJOURNAL OF FOOD SCIENCE, Issue 2 2005Suzanne D. Johanningsmeiner ABSTRACT: Sour taste has been considered the simplest of the basic tastes because it is elicited only by hydrogen ions. However, there is not a sufficiently clear understanding of that relationship to allow sour taste intensity to be predicted and rationally modified in foods. On the basis of analysis of sensory data from our laboratory and reanalysis of previously published data, we propose a new hypothesis for the chemical basis for sour taste perception: The intensity of sour taste perception in acid solutions or acidified foods is linearly related to the molar concentration of all organic acid species with at least 1 protonated carboxyl group plus the molar concentration of free hydrogen ions. This hypothesis implies that, on a molar basis, different organic acids will be equally sour, provided at least 1 carboxyl group is protonated. The major effect of pH on sour taste will be to determine the degree of protonation of organic acids. If this hypothesis is confirmed, it will provide a new understanding of the chemical basis for this basic taste perception and have broad usefulness in the formulation of products in which sour taste is an important component of flavor. [source] Propylene/propane separation by vacuum swing adsorption using 13X zeoliteAICHE JOURNAL, Issue 2 2001Francisco A. Da Silva A vacuum swing adsorption process using 13X zeolite pellets with five steps was designed to split an equimolar mixture of propylene/propane: pressurization with feed; high-pressure feed; high-pressure purge with product; cocurrent blowdown; and counter-current vacuum blowdown, where the enriched propylene product is withdrawn. In the process, the partial pressure of the C3 -mixture is controlled with nitrogen, which is used as inert gas. With an equimolar feed of C3 diluted to 50% with nitrogen, the column is fed at 5 bar and 423 K, and the product is obtained when the total pressure is lowered to 0.1 bar. After 15,20 cycles, the cyclic steady-state condition is achieved, a propylene-enriched stream of 98% mol relative to propylene/propane mixture, with 3.2% of nitrogen, a recovery of 19% (molar basis), and a productivity of 0.785 mol/kg·h is obtained. The experimental work was complemented with numerical simulations, and the effect of different operating parameters on the performance of the VSA was considered. [source] Density, Surface Tension, and Viscosity of PbO-B2O3 -SiO2 Glass MeltsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2004Shigeru Fujino The density, surface tension, and viscosity of the melts from the PbO-B2O3 -SiO2 system have been measured at temperatures in the range 1073,1473 K. The effect of composition on these properties was also investigated. The density of the melt was found to increase linearly with increasing PbO content. Molar volume was derived from the density data, and its deviation from the additivity of partial molar volumes was calculated. These deviations in molar volume from those obtained from additivity rules have been used along with the ratio of various coordination numbers of boron (as reported by Bray) to discuss the structure of the melts. The surface tension was found to decrease with decreasing SiO2/B2O3 ratio, and to increase in the range of the PbO content between 30 and 60 mol%, showing a maximum at ,60 mol% PbO, and then decreased with further additions. This result suggested that the surface tension would be affected primarily by the B2O3 content in the range of the PbO content between 30,60 mol%, and mainly by the PbO content in the range of the PbO content >60 mol%, respectively. The viscosity of the melt was found to decrease linearly with increasing PbO content. The results obtained indicate that the increase in viscosity with B2O3 was half that of SiO2 (on a molar basis), and an empirical equation has been proposed for the viscosity as a function of mole fraction. [source] Tebuconazole dissipation and metabolism in Tifton loamy sand during laboratory incubation,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 7 2004Timothy C Strickland Abstract The fungicide tebuconazole is widely used to control soil-borne and foliar diseases in peanuts and other crops. No published data are currently available on the extent and rate at which this compound degrades in soil. Unpublished data summarized in registration documents suggest that the compound is persistent, with 300,600 days half-life. We conducted a 63-day laboratory incubation to evaluate tebuconazole's dissipation kinetics and impact on soil microbial activity in Tifton loamy sand. Tifton soils support extensive peanut production in the Atlantic Coastal Plain region of Georgia and Alabama. Products containing tebuconazole are applied to an estimated 50% of the peanut acreage in the region. At the end of the incubation, 43 (±42)% of the parent compound was recovered in soil extracts. The first-order kinetic model, which gave a good fit to the dissipation data (r2 = 0.857), yielded a soil half-life (t1/2) of 49 days. This is 6,12 times more rapid than t1/2 values described in unpublished tebuconazole registration documents. Four degradates were identified. Tentative structural assignments indicated that degradates were derived from hydroxylation of the parent compound and/or chlorophenyl ring cleavage. Cleavage products showed a steady increase during the incubation, and on a molar basis were equal to 63% of the time zero tebuconazole concentration. No significant effect on soil microbial biomass was observed, indicating that when the compound is applied at normal agronomic rate it does not impact soil metabolic activity. Use of the soil-half life data derived in this study should improve the accuracy of tebuconazole fate assessments for Coastal Plain peanut production. The study also indicated that environmental assessment of selected degradates may be needed to fully evaluate risks of tebuconazole use. Published in 2004 for SCI by John Wiley & Sons, Ltd. [source] Soluble sugar content of white spruce (Picea glauca) seeds during and after germinationPHYSIOLOGIA PLANTARUM, Issue 1 2000Bruce Downie In white spruce (Picea glauca [Moench.] Voss.) seeds, the raffinose family oligosaccharides (RFOs) provide carbon reserves for the early stages of germination prior to radicle protrusion. Some seedlots contain seeds that are dormant, failing to complete germination under optimal conditions. Since dormancy may be imposed through a metabolic block in reserve mobilization, the goal of this project was to identify any impediment to RFO mobilization in dormant relative to nondormant seeds. Desiccated seeds contain primarily, and in order of abundance on a molar basis, sucrose and the first 3 members of the RFOs, raffinose, stachyose and verbascose. Upon radicle protrusion at 25°C, the contents of RFOs decreased to low amounts in all seed parts, regardless of prior dormancy status and sucrose was metabolized to glucose and fructose, which increased in seed parts. During moist chilling at 4°C, RFO content initially decreased before stabilizing and then increasing. In seeds that did not complete germination, the synthesis of RFOs at 4°C favored verbascose, so that at the end of 14 (nondormant) or 35 (dormant) weeks, verbascose contents in megagametophytes exceeded the amount initially present in the desiccated seed. This was also true in the embryos of the dormant seedlot. In seed parts from both seedlots after months of moist chilling, stachyose amounts exceeded raffinose amounts. Upon radicle protrusion at 4°C, RFO contents decreased to amounts most similar to those present in seeds that completed germination at 25°C. Hence, the RFOs are utilized as a source of energy, regardless of the temperature at which white spruce seeds complete germination. Based on the similarity of sugar contents in seed parts between dormant and nondormant seeds that did not complete germination, differences in sugar metabolism are probably not the basis of dormancy in white spruce seeds. [source] Synthesis and characteristics of novel chelate fiber containing amine and amidine groupsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2004Dong Hun Shin Abstract A polyacrylonitrile (PAN) fiber was adopted for the backbone of a chelate polymer and poly(acrylo-amidino ethylene amine) (PAEA) was prepared through a one-step reaction between the PAN fiber and ethylenediamine (EDA). The maximum removal capacity and degree of substitution were 7.8,meq per gram of dried PAEA and 98%, respectively. The PAEA was tested as an adsorbent in single and two-component metal aqueous solutions under changing pH. The Cu2+ ion accomplished maximum adsorption amount at pH 3 and the order of maximum adsorbed amounts on PAEA is Cu2+,>,Ag+,>,Zn2+,>,Ni2+,>,Pb2+ in molar basis. FT-IR spectroscopy was employed to characterize the chemical bonding in metal aqueous solutions and surface morphology was examined using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||||||||