Evaluation of Substrate Consumption Kinetics in Different Support Materials for Biotrickling Filters Aiming Biogas Desulfurization

2017 ◽  
Vol 262 ◽  
pp. 682-686 ◽  
Author(s):  
Letícia Ferraresi Hidalgo ◽  
Jessyka Lima Santos ◽  
Samir Prioto Tayar ◽  
Arnaldo Sarti ◽  
Mauricio Cesar Palmieri ◽  
...  
Keyword(s):  
Polyurethane Foam ◽  
Fossil Fuels ◽  
Microbial Colonization ◽  
Substrate Consumption ◽  
Support Materials ◽  
Biotrickling Filters ◽  
Polyethylene Terephtalate ◽  
Kinetics Of ◽  
Selection Of ◽  
Main Factor

Biogas is a renewable energy source that can be used to produce heat and energy, replacing fossil fuels. The main factor limiting the use of biogas is contaminants in its composition which H2S is the most important due to corrosion and environmental problems. A promising technology to remove this contaminant from biogas is the biotrickling filters and the selection of inexpensive and durable supports is an important step for the operation. This work has studied different support materials, for microorganisms immobilization, as Polyvinyl Chloride (PVC), Polyethylene Terephtalate (PET), Polytetrafluoroethylene (Teflon®) comparing to open pore polyurethane foam (OPP) each one packed in biotrickling filters to evaluate the consumption of thiosulfate by chemolitotrofic microorganisms. The kinetics of substrate consumption in different cycles for each support were distinct suggesting different microbial colonization. The materials tested have presented results very similar polyurethane foam, which has already known by its efficiency on biogas desulfurization, unless Teflon that has showed a divergent result with the increase of the substrate concentration in the system.

Trypsin entrapped within liposomes. Partition of a low-molecular-mass substrate as the main factor in kinetic control of hydrolysis

1991 ◽  
Vol 56 (3) ◽  
pp. 712-717 ◽  
Author(s):  
Jana Formelová ◽  
Albert Breier ◽  
Peter Gemeiner ◽  
Lubica Kurillová
Keyword(s):  
Molecular Mass ◽  
Egg Yolk ◽  
Kinetic Control ◽  
Hydrolysis Kinetics ◽  
Liposomal Membrane ◽  
Kinetics Of ◽  
Main Factor

Trypsin has been entrapped within liposomes prepared from egg yolk phospholipides by the method of controlled dialysis, and the hydrolysis kinetics of Nα-benzoyl-DL-arginine p-nitroaniline catalyzed by the liposome-entrapped trypsin has been studied by monitoring the flux of substrate and product across the liposomal membrane. The partitioning of the substrate and product between liposomal and extraliposomal environment has been found to represent the main factor in the kinetic control of the hydrolysis.

Elaboration and Characterization of the Properties of Refractory Cr Base Alloys

2010 ◽  
Vol 72 ◽  
pp. 46-52 ◽  
Author(s):  
Laurent Royer ◽  
Stéphane Mathieu ◽  
Christophe Liebaut ◽  
Pierre Steinmetz
Keyword(s):  
Mechanical Properties ◽  
Melting Point ◽  
Molten Glass ◽  
Energy Production ◽  
Creep Properties ◽  
Refractory Alloys ◽  
Industrial Use ◽  
Kinetics Of ◽  
Selection Of

For energy production and also for the glass industry, finding new refractory alloys which could permit to increase the process temperatures to 1200°C or more is a permanent challenge. Chromium base alloys can be good candidates, considering the melting point of Cr itself, and also its low corrosion rate in molten glass. Two families of alloys have been studied for this purpose, Cr-Mo-W and Cr-Ta-X alloys (X= Mo, Si..). A finer selection of compositions has been done, to optimize their chemical and mechanical properties. Kinetics of HT oxidation by air, of corrosion by molten glass and also creep properties of several alloys have been measured up to 1250°C. The results obtained with the best alloys (Cr-Ta base) give positive indications as regards the possibility of their industrial use.

scholarly journals Role of antigen, CD8, and cytotoxic T lymphocyte (CTL) avidity in high dose antigen induction of apoptosis of effector CTL.

1996 ◽  
Vol 184 (2) ◽  
pp. 485-492 ◽  
Author(s):  
M A Alexander-Miller ◽  
G R Leggatt ◽  
A Sarin ◽  
J A Berzofsky
Keyword(s):  
T Lymphocytes ◽  
Cytotoxic T Lymphocyte ◽  
Target Cells ◽  
High Dose ◽  
High Avidity ◽  
Apoptotic Pathway ◽  
Peptide Antigen ◽  
Kinetics Of ◽  
Selection Of

Experimental data suggest that negative selection of thymocytes can occur as a result of supraoptimal antigenic stimulation. It is unknown, however, whether such mechanisms are at work in mature CD8+ T lymphocytes. Here, we show that CD8+ effector cytotoxic T lymphocytes (CTL) are susceptible to proliferative inhibition by high dose peptide antigen, leading to apoptotic death mediated by TNF-alpha release. Such inhibition is not reflected in the cytolytic potential of the CTL, since concentrations of antigen that are inhibitory for proliferation promote efficient lysis of target cells. Thus, although CTL have committed to the apoptotic pathway, the kinetics of this process are such that CTL function can occur before death of the CTL. The concentration of antigen required for inhibition is a function of the CTL avidity, in that concentrations of antigen capable of completely inhibiting high avidity CTL maximally stimulate low avidity CTL. Importantly, the inhibition can be detected in both activated and resting CTL. Blocking studies demonstrate that the CD8 molecule contributes significantly to the inhibitory signal as the addition of anti-CD8 antibody restores the proliferative response. Thus, our data support the model that mature CD8+ CTL can accommodate an activation signal of restricted intensity, which, if surpassed, results in deletion of that cell.

Mechanodestruction of Isoprene Rubber. Part 1. Process Kinetics

2021 ◽  
Vol 80 (3) ◽  
pp. 118-122
Author(s):  
V.P. Dorozhkin ◽  
◽  
E.G. Mokhnatkina ◽  
D.N. Zemsky ◽  
A.D. Valiev ◽  
...  
Keyword(s):  
Experimental Data ◽  
Molecular Mass ◽  
Rate Constants ◽  
Oxidative Destruction ◽  
Process Kinetics ◽  
Mass Fractions ◽  
Rubber Part ◽  
Kinetics Of ◽  
Selection Of ◽  
Isoprene Rubber

A method is proposed that allows us to obtain the values of the rate constants (CR) of the processes of mechanodestruction (mechanical cracking) of kм, oxidative destruction of kо, and recombination of kр macromolecules, as well as the mass fractions of the corresponding fractions of φм, φо, and φр,r involved in the plasticization process (P) of SKI-3 isoprene rubber. The method is based on the selection of the values of these parameters that correspond to the previously obtained experimental data, using the previously obtained recurrent equations and a specially developed program. The dependences of the CR on the time P at 30oC are obtained, which allows us to describe the kinetics of the processes accompanying P at this temperature, and the changes in molecular mass (MM) in this process. It is shown that constant values of CR are established at large times of P. Refined explanations of the nature of the kinetics of the CR change at P are proposed. The MM value of SKI-3 macromolecules that have not undergone destruction is calculated, depending on the time of plasticization.

The prioritization of renewable energy technologies in Pakistan: An urgent need

2021 ◽  
pp. 81-103
Author(s):  
Leezna Saleem ◽  
Imran Ahmad Siddiqui ◽  
Intikhab Ulfat
Keyword(s):  
Renewable Resources ◽  
Fossil Fuels ◽  
Renewable Resource ◽  
Energy System ◽  
The Past ◽  
Energy Technologies ◽  
Energy Needs ◽  
Environmental Criteria ◽  
Populous Country ◽  
Selection Of

Pakistan is the world's sixth most populous country, currently facing the worst energy crisis. Although rich in renewable resources, Pakistan's energy system relies mainly on fossil fuels and imported energy for its energy needs. This study aims to use an analytical hierarchy pro-cess to prioritize six renewable technologies for Pakistan, with four criteria and thirteen subcriteria. The results indicate that solar power is particularly well suited for Pakistan, as it gained 42% priority weightage in the final aggregation. Wind energy is ranked second with a priority weight of 24%, followed by hydro 13%, biomass 9%, ocean 8% and geothermal en-ergy 3%. Solar and wind energies accounted for nearly 66% of the total weightage. This result highlighted the significance of economic criteria for the selection of renewable technologies in Pakistan, with around 43% priority weightage. Environmental criteria gained 19% whereas socio-political criteria registered 14% and technical criteria 23% priority weightage. During the potential assessment of the research, it was concluded that although renewable resource development has not been allocated sufficient attention in Pakistan in the past, if the correct decisions are taken regarding the exploitation of these resources, this can remedy the country's hazardous dependence on fossil fuel and imported energy.

Source Functions of CO2 and Future CO2 Burden in the Atmosphere

1977 ◽  
Vol 32 (12) ◽  
pp. 1544-1554
Author(s):  
K. E. Zimen ◽  
P. Offermann ◽  
G. Hartmann
Keyword(s):  
Fuel Consumption ◽  
Fossil Fuels ◽  
Source Function ◽  
Fossil Fuel ◽  
Status Quo ◽  
Growth Coefficient ◽  
Mauna Loa ◽  
Fossil Fuel Consumption ◽  
The Future ◽  
Kinetics Of

Abstract A logistic source function for CO2 was derived which takes into account the input arising from the burning of fossil fuels, the stimulation of photosynthesis by the increasing partial pressure of CO2, and the decrease of biomass through deforestation etc. The parameters in a 5-box-model for the kinetics of CO2 were adjusted to fit the new Mauna Loa data on CO2 concentrations in air. Using these parameters and a buffer factor ξ(t) for the absorption of CO2 into the sea, the future CO2 burden was calculated for status quo conditions and for different values of the growth coefficient of fossil fuel consumption. The results show that one can change the deforestation factor in rather wide limits without changing very much the future CO2 concentration in air during the next 80 years or so (cf. Figure 4). On the other hand, the future C02 burden depends strongly on the growth rate of fossil fuel consumption and will double under status quo conditions early in the next century (cf. Figure 5).

Pre-selection of flocculants by the LUMiFuge separation analyser 114

2002 ◽  
Vol 46 (4-5) ◽  
pp. 441-446 ◽  
Author(s):  
T. Sobisch ◽  
D. Lerche
Keyword(s):  
Dynamic Behaviour ◽  
Test Procedure ◽  
Centrifugal Acceleration ◽  
Sludge Dewatering ◽  
Total Solids ◽  
Shear Sensitivity ◽  
Compression Behaviour ◽  
Sludge Cake ◽  
Kinetics Of ◽  
Selection Of

This paper reports on lab-scale investigations in relation to pre-selection of flocculants for sludge dewatering with decanter centrifuges. Results obtained were compared with CST-measurements and discussed in relation to findings under field conditions. Experiments were carried out with sewage sludges of different origin and characteristics and a number of commercial flocculants. Kinetics of sedimentation and clarification were measured as well as the compression behaviour and shear sensitivity of sludge sediments. To measure flocculant performance stability against intensive shearing, total solids in the sludge cake obtained and dewaterability of the sludge cake during the first 20-50 s of centrifugation were compared. A screening test procedure was developed. Efficient flocculants should produce high residual total solids and good initial compressibility. Lab-scale investigations deliver more reliable results if the dynamic behaviour of the sludge under centrifugal acceleration is also investigated. The separation analyser LUMiFuge 114 can provide results about the compression behaviour of sludges in the range between 10 and 100 s. So far no other method or device is known which can deliver such results.

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