The Ash-Bed Effect in Eucalyptus regnans Forest: Chemical, Physical and Microbiological Changes in Soil After Heating or Partial Sterilisation

1994 ◽  
Vol 42 (6) ◽  
pp. 739 ◽  
Author(s):  
DP Chambers ◽  
PM Attiwill
Keyword(s):  
Treatment Time ◽  
Microbial Populations ◽  
Nitrogen And Phosphorus ◽  
Γ Irradiation ◽  
Tissue Concentrations ◽  
Eucalyptus Regnans ◽  
Temperature Heat ◽  
Chemical Sterilization ◽  
Partial Sterilization ◽  
Lower Temperature

The ash-bed effect (the enhanced growth of plants on soil which has been heated) following fire in Eucalyptus regnans forest is dramatic. The results are presented of studies of the effects of a range of heating and partial sterilization treatments on chemical, microbiological and physical properties in soil from a 250-year-old E. regnans forest in Victoria. Soil treatments not involving heat (chemical sterilization, γ -irradiation and air-drying) and the lower temperature heat treatments (100 and 200°C) had no marked effects on physical characteristics. All treatments produced more or less similar effects on microbial populations. On the other hand, heating the soil to 400-600°C produced large, significant and sustained increases in the availability of nitrogen and phosphorus and these increases were enhanced by a decrease in clay colloid. The results support the hypothesis that the ash-bed effect following fire in E. regnans forest is due to an increase in the availability of nutrients, and in the availability of nitrogen and phosphorus in particular. A transitory increase in the concentration of manganese caused by heating the soil may account for initial toxicity in plants grown in soils which have been heated. Since species within the subgenus Monocalyptus are characterized by lower tissue concentrations of manganese than those within Symphyomyrtus, it could be hypothesized that the potential for toxicity following bushfire varies between the two subgenera. The literature on the effects of soil-sterilising treatments is highly variable; the causes of variability include soil type and moisture content, treatment (sterilizing by steam, chemicals or heat) and the method of treatment (time, how the soil was contained, and how the treatment was applied).

scholarly journals Characteristic Study of Briquette Cyanobacteria as Fuel in Chemical Looping Combustion with Hematite as Oxygen Carrier

2021 ◽  
Vol 11 (10) ◽  
pp. 4388
Author(s):  
Haifeng Zhang ◽  
Laihong Shen ◽  
Huijun Ge ◽  
Hongcun Bai
Keyword(s):  
Large Scale ◽  
Oxygen Carrier ◽  
Compressive Load ◽  
Phosphorus Recovery ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Carbon Conversion ◽  
Nitrogen And Phosphorus ◽  
Liquid Products ◽  
Lower Temperature

Due to the more and more serious cyanobacteria bloom problem, it is particularly urgent to find a technology suitable for large-scale disposal and the efficient recovery of abundant nitrogen and phosphorus resources in cyanobacteria. The combination of chemical looping combustion (CLC) and biomass densification technology is thought to be a promising utilization selection. Based on the experimental results, the mechanical strength and energy density of briquette cyanobacteria are evidently increased with the compressive load; whereas, 10% is the optimal moisture content in the densification process. A higher heating rate in TGA would result in the damage of the internal structure of the briquette cyanobacteria, which are conducive to the carbon conversion efficiency. The presence of a hematite oxygen carrier would enhance the carbon conversion and catalyzed crack liquid products. CO2 yield is increased 25 percent and CH4 yield is decreased 50 percent at 900 °C in the CLC process. In addition, the lower temperature and reduction atmosphere in CLC would result in a lower NO emission concentration. The reactivity and porous property of hematite OC in CLC also increased during 10 redox cycle experiments. The CLC process accelerates the generation of CaH2P2O7 and CaHPO4 in cyanobacteria ash, which is more conducive to phosphorus recovery.

scholarly journals Efficacy of Three Light Technologies for Reducing Microbial Populations in Liquid Suspensions

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Angeliki Birmpa ◽  
Apostolos Vantarakis ◽  
Spyros Paparrodopoulos ◽  
Paul Whyte ◽  
James Lyng
Keyword(s):  
Treatment Time ◽  
Limit Of Detection ◽  
Foodborne Pathogen ◽  
Microbial Populations ◽  
Liquid Matrix ◽  
E Coli ◽  
Bactericidal Efficacy ◽  
The Common ◽  
Liquid Suspensions ◽  
Uv C

The aim of the current study was to evaluate the effectiveness of three nonthermal light technologies (NUV-Vis, continuous UV, and HILP) on their ability to inactivateEscherichia coliK12 andListeria innocua.  E. coliK12 was selected as a representative microorganism for the enterohaemorrhagic foodborne pathogenE. coliO157:H7 andL. innocuaas a surrogate microorganism for the common foodborne pathogenListeria monocytogenes, respectively. The liquid matrix used for the disinfection experiments was a liquid matrix (MRD solution). The results of the present study show that the HILP treatment inactivated bothE. coliandL. innocuamore rapidly and effectively than either continuous UV-C or NUV-vis treatment. With HILP at 2.5 cm from the lamp,E. coliandL. innocuapopulations were reduced by 3.07 and 3.77 log10CFU/mL, respectively, after a 5 sec treatment time, and were shown to be below the limit of detection (<0.22 log10CFU/mL) following 30 sec exposure to HILP (106.2 J/cm2). These studies demonstrate the bactericidal efficacy of alternative nonthermal light technologies and their potential as decontamination strategies in the food industry.

Effect of Low Temperature Heat Treatment for R512E Coated C-103 Nb Alloy

2021 ◽  
Vol 875 ◽  
pp. 266-271
Author(s):  
Shaikh Asad Ali Dilawary ◽  
Muhammad Khalid ◽  
Amjad Ali ◽  
Hamid Zaigham
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Low Temperature ◽  
Dwell Time ◽  
Silicide Coating ◽  
Oxidation Protection ◽  
Time Period ◽  
Temperature Heat ◽  
Lower Temperature ◽  
Temperature Heat Treatment

The article aims to investigate the feasibility of oxidation protection imparted to C-103 Nb-based alloy by fused slurry silicide coating of R512E (60Si20Fe20Cr) carried out at lower temperature (1200 °C) for higher dwell time i.e. 12 hours. The findings reveal that the coating treated can impart sufficient oxidation resistance the alloy, which may withstand the desired application conditions wherein oxidation protection for smaller time period is needed. Moreover, this treatment is not found to deteriorate other mechanical properties of the alloy in 'As coated' condition.

THE EFFECT OF BIOREMEDIATION ON THE MICROBIAL POPULATIONS OF OILED BEACHES IN PRINCE WILLIAM SOUND, ALASKA

1993 ◽  
Vol 1993 (1) ◽  
pp. 469-475 ◽  
Author(s):  
Roger C. Prince ◽  
Richard E. Bare ◽  
Graham N. George ◽  
Copper E. Haith ◽  
Matthew J. Grossman ◽  
...  
Keyword(s):  
Oil Spill ◽  
Natural Process ◽  
Significant Fraction ◽  
Indigenous Populations ◽  
Microbial Populations ◽  
Prince William Sound ◽  
Nitrogen And Phosphorus ◽  
Degrading Bacteria ◽  
Assimilable Nitrogen ◽  
Stimulation Of

ABSTRACT Bioremediation, the stimulation of the natural process of biodegradation, played an important role in the cleanup of the oil spill from the Exxon Valdez in Prince William Sound, Alaska. Since there were already substantial indigenous populations of oil-degrading microbes in the area, it was apparent that degradation was likely to be nutrient—not microbial—limited. Bioremediation therefore involved the application of carefully selected fertilizers to provide assimilable nitrogen and phosphorus to the indigenous organisms, with the intent to stimulate their activity and enhance their numbers. We show here that the indigenous microbial populations were indeed substantially increased, throughout the sound, approximately one month after widespread fertilizer applications in both 1989 and 1990. Furthermore, while oil-degrading bacteria made up a significant fraction of the microbial populations on contaminated beaches in September and October 1989, they had declined to less than 1 percent by the summer of 1990, suggesting that the microbial populations on the shorelines were returning to their pre-spill conditions.

A Novel High-Temperature Ejector-Topping Power Cycle

1994 ◽  
Vol 116 (1) ◽  
pp. 1-7 ◽  
Author(s):  
B. Z. Freedman ◽  
N. Lior
Keyword(s):  
High Temperature ◽  
Heat Source ◽  
Gas Turbines ◽  
Saturation Pressure ◽  
Temperature Cycle ◽  
Power Cycle ◽  
Primary Fluid ◽  
Temperature Heat ◽  
Lower Temperature ◽  
Secondary Fluid

A novel, patented topping power cycle is described that takes its energy from a very high-temperature heat source and in which the temperature of the heat sink is still high enough to operate another, conventional power cycle. The top temperature heat source is used to evaporate a low saturation pressure liquid, which serves as the driving fluid for compressing the secondary fluid in an ejector. Due to the inherently simple construction of ejectors, they are well suited for operation at temperatures higher than those that can be used with gas turbines. The gases exiting from the ejector transfer heat to the lower temperature cycle, and are separated by condensing the primary fluid. The secondary gas is then used to drive a turbine. For a system using sodium as the primary fluid and helium as the secondary fluid, and using a bottoming Rankine steam cycle, the overall thermal efficiency can be at least 11 percent better than that of conventional steam Rankine cycles.

Direct and indirect effects of calcium sulfate and nitrogen on growth and succession of trees on the Tanana River floodplain, interior Alaska

1993 ◽  
Vol 23 (5) ◽  
pp. 995-1000 ◽  
Author(s):  
F. Stuart Chapin III ◽  
Lawrence R. Walker
Keyword(s):  
Polyethylene Glycol ◽  
Calcium Sulfate ◽  
Nitrogen Addition ◽  
Nutrient Accumulation ◽  
Sensitive Species ◽  
Nitrogen And Phosphorus ◽  
Tissue Concentrations ◽  
Balsam Poplar ◽  
Low Nitrogen ◽  
Potential Transpiration

Seedlings of Alaskan floodplain species (Populusbalsamifera L. (balsam poplar), Alnustenuifolia Nutt. (thinleaf alder), and Piceaglauca (Moench) Voss (white spruce)) and an upland species (Populustremuloides Michx. (trembling aspen)) were grown in early-successional floodplain soils treated with a floodplain salt (calcium sulfate, CaSO4), an osmoticant (polyethylene glycol), and nitrogen. CaSO4 reduced the growth of aspen relative to controls but also reduced the growth of some typical floodplain colonizers (alder at low nitrogen and poplar at high nitrogen). Aspen and poplar were the most rapidly growing species, even when grown with salt or polyethylene glycol. Effects of CaSO4 on growth, therefore, do not explain why aspen is less abundant on the floodplain than are typical floodplain colonizers. CaSO4 reduced growth directly in salt-sensitive species, judging from the insensitivity of water potential, transpiration, and photosynthesis to CaSO4 addition. Tissue concentrations of nitrogen and phosphorus were unaffected by CaSO4, suggesting that the declines in nutrient accumulation by salt-sensitive species in response to CaSO4 addition reflected a decline in nutrient demands for growth rather than being the cause of the reduction in growth. Growth and nutrient accumulation were stimulated by nitrogen addition in all species. We suggest that floodplain salts may be important in succession by slowing the establishment and growth of alder, which is responsible for most of the nitrogen acquired by plants during succession.

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