Anaerobic biodegradability of polyvinyl alcohol

Summary Biodegradability of polyvinyl alcohol (PVA) under anaerobic conditions was demonstrated using anaerobic river sediments and anaerobically treated activated sludge from a sewage treatment plant. PVA having molecular weights of 2000 and 14000 was over 60% biodegraded as determined by TOC.     

The action of two classes of pyrethroids on the inhibition of brain Na-Ca and Ca + Mg ATP hydrolyzing activities of the American cockroach

Ca2+-stimulated ATP hydrolyzing activities (i.e. Na-Ca ATP hydrolysis and Ca + Mg ATP hydrolysis) measured in cockroach brain tissue were highly sensitive to the action of pyrethroid insecticides under in vitro conditions. Non-cyano-containing pyrethroids inhibited Na-Ca ATP hydrolysis to a greater extent than their cyano-containing counterparts. The reverse is true for pyrethroid action on Ca + Mg ATP hydrolysis. Nonmitochondrial Ca + Mg ATP hydrolysis of disrupted synaptosomes was the most sensitive activity examined. Ca2+-stimulated ATP hydrolyzing activities were inhibited in cockroaches poisoned by permethrin in vivo. In vivo poisoning occurred in the presence of a similar amount of bound [14C]permethrin which had been determined to cause a substantial amount of inhibition to Ca2+-stimulated ATP hydrolyzing activities in vitro.     

Separation of dilute aqueous butanol and acetone solutions by pervaporation through liquid membranes

A simultaneous extraction-stripping process is proposed for separating volatile products from fermentation broths, it is based on pervaporation through a liquid membrane supported with a hydrophobic porous membrane. The liquid membrane prepared with oleyl alcohol was selected as the most suitable for separating volatile products resulting from acetone-butanol fermentation. The separation performance and stability of the oleyl alcohol liquid membrane were investigated by using dilute aqueous butanol and acetone solutions. The oleyl alcohol liquid membrane was found to be superior by far in both selectivity and permeability of butanol to the better known silicone rubber membrane in its high selectivity for alcohols. Using the oleyl alcohol liquid membrane, the dilute aqueous butanol solutions of around 4 g/L obtained in acetone-butanol fermentation could be concentrated up to 100 times. The stability of this liquid membrane was also quite good as long as the surface tension of the feed solution was less than the critical surface tension of the support membrane. No change in the separation performance was found after the continuous usage in a long period of 100 h.     

Energy saving effect of pervaporation using oleyl alcohol liquid membrane in butanol purification

The liquid membrane prepared with oleyl alcohol was used in pervaporation of dilute aqueous butanol solutions. The selectivity of this liquid membrane was found to be superior than that of silicone rubber membrane, and the separation factor for butanol was 180. Energy saving effect of pervaporation in butanol purification was investigated by comparing the energies required to purify a butanol solution of 0.5 wt.% in the following three separation systems; a conventional distillation system, a separation system combining pervaporation with distillation, and a pervaporation system using a hydrophobic membrane and a hydrohylic membrane in series. When the pervaporation using oleyl alcohol liquid membrane was employed as a pretreatment process of butanol purification, the energy requirement was found to be around one-tenth of that of conventional distillation.List of Symbols E _D MJ/kg Specific energy requirement of butanol purification by distillation - J kg/(m² · h) Total permeation flux - J _B kg/(m² · h) Permeation flux of butanol - P ₁, P ₂ MPa Pressure at inlet and outlet of vacuum pump - Q kJ/h Energy transfer rate - Q _C Q _W kJ/h Energy consumption rate of condenser and vacuum pump - R J/K · mol Gas constant - t, T °C, K Temperature - W-g/h Mass flow rate of butanol/water binary mixture - (W) _F1 ,-kg/h Mass flow rate of aqueous butanol solution - (W) _F2 at inlet and outlet of permeation cell - W* kJ/mol Energy requirement of adiavatic expansion - X _B Butanol mass fraction of aqueous butanol solution - (X _B ) _F Butanol mass fraction of aqueous butanol solution supplied into distillation column - (X _B ) _F1 Butanol mass fraction of aqueous butanol - (X _B ) _F2 solution at inlet and outlet of permeation cell - Y _B Butanol mass fraction in permeate - Separation factor of butanol - Adiavatic constant     

Distribution and possible intergradation betweenMacaca tonkeana andM. ochreata at the borderland of the species in Sulawesi

Morphological observations of pet and wild monkeys were made in the area that was inferred to be the borderland betweenMacaca tonkeana andM. ochreata in Sulawesi. Almost all individual monkeys could be classified into one of two species by their external characteristics. The possible borderland was estimated to extend from the La River in the east and to around Karaena River in the west. These two species may make contact in the forest in the western area of the borderland. Some external characteristics exhibited wide individual variations in the two species. Some monkeys originating from the borderland showed external characteristics that were intermediate between those of the two species. The possible intergradation between these two species is discussed in terms of the morphological variations found in the two species.