scholarly journals Rheological characteristics of filamentous cultivation broths and suitable model fluids

2020 ◽  
Vol 163 ◽  
pp. 107746 ◽  
Author(s):  
C. Bliatsiou ◽  
K. Schrinner ◽  
P. Waldherr ◽  
S. Tesche ◽  
L. Böhm ◽  
...  
Keyword(s):  
Suitable Model ◽  
Rheological Characteristics ◽  
Model Fluids

Chemical modification of the bacterial wall to determine sites of metal deposition

1978 ◽  
Vol 36 (2) ◽  
pp. 350-351
Author(s):  
T. J. Beveridge
Keyword(s):  
Electron Scattering ◽  
Metal Salt ◽  
Metal Deposition ◽  
Suitable Model ◽  
X Ray Diffraction ◽  
Subtilis Cell ◽  
Thin Sections ◽  
X Ray ◽  
Section Data ◽  
Metal Impregnation

The Bacillus subtilis cell wall provides a protective sacculus about the vital constituents of the bacterium and consists of a collection of anionic hetero- and homopolymers which are mainly polysaccharidic. We recently demonstrated that unfixed walls were able to trap and retain substantial amounts of metal when suspended in aqueous metal salt solutions. These walls were briefly mixed with low concentration metal solutions (5mM for 10 min at 22°C), were well washed with deionized distilled water, and the quantity of metal uptake (atomic absorption and X-ray fluorescence), the type of staining response (electron scattering profile of thin-sections), and the crystallinity of the deposition product (X-ray diffraction of embedded specimens) determined.Since most biological material possesses little electron scattering ability electron microscopists have been forced to depend on heavy metal impregnation of the specimen before obtaining thin-section data. Our experience with these walls suggested that they may provide a suitable model system with which to study the sites of reaction for this metal deposition.

The Filter Loop Technique as a Method of Measuring Platelet Aggregation in the Flowing Blood of the Rat; the Inhibitory Activity of 5-oxo-l-cyclopentene-l-heptanoic Acid (AY-16,804) on Platelet Aggregation

1973 ◽  
Vol 30 (01) ◽  
pp. 138-147 ◽  
Author(s):  
Christopher R. Muirhead
Keyword(s):  
Platelet Aggregation ◽  
Prostaglandin E1 ◽  
Suitable Model ◽  
Heptanoic Acid ◽  
Simple Method ◽  
Loop Technique ◽  
Flowing Blood ◽  
Filter Loop

SummaryThe filter loop technique which measures platelet aggregation in vivo in the flowing-blood of the rat was compared to the optical density technique of Born which is carried out in vitro with platelet rich plasma. Using these two experimental models the effect on platelet aggregation of three known inhibitors sulfinpyrazone, dipyridamole and prostaglandin E1, and a novel compound 5-oxo-l-cyclopentene-l-heptanoic acid (AY-16, 804) was determined.The effects on platelet aggregation of the known inhibitors were consistent with information in the literature. Prostaglandin E1 was the most potent inhibitor in both techniques; sulfinpyrazone inhibited aggregation in both models but was less potent than prostaglandin E1. AY-16, 804 exhibited activity in vitro and in vivo similar to that of sulfinpyrazone. Dipyridamole did not inhibit platelet aggregation in vivo and did not inhibit aggregation in vitro in concentrations at which it remained soluble.The filter loop technique is a suitable model for measuring platelet aggregation in the flowing blood of the rat. It is a relatively simple method of determining aggregation and easily adapted to other species.

A SOFT SYSTEMS METHODOLOGY APPROACH TO IMPROVING THE SUPPLY CHAIN OF A CONSTRUCTION PROJECT IN GAUTENG PROVINCE, SOUTH AFRICA

2020 ◽  
Vol 10 (1) ◽  
pp. 86-99
Author(s):  
Lewis Tsuro ◽  
Stan Hardman
Keyword(s):  
South Africa ◽  
Supply Chain ◽  
Construction Project ◽  
Soft Systems Methodology ◽  
Project Planning ◽  
Suitable Model ◽  
Senior Managers ◽  
Good Tool ◽  
Systems Methodology ◽  
Soft Systems

The Soft Systems Methodology (SSM) was developed as a set of tools for identifying and making incremental steps to improve situations with poorly defined causes or solutions. The supply chain forms a key process of any construction project; however, on any given construction site, supply chain inefficiencies could arise from many different avenues. Opinions vary, though, on which of these avenues is more important for increasing supply chain efficiencies; whether any problem even exist across the different aspects of the supply chain; as well as what steps should be taken to resolve them. It was therefore studied, here, whether SSM could be employed as a useful tool to systematically apply in the supply chains of a construction project in South Africa, for understanding and targeting the problematic situations that arise. Following thorough cyclical open-ended interviews with 17 workers, supervisors, foremen, site clerks, senior managers, and the CEO of the principal contractor at a new office park construction project in Rosebank, Johannesburg, and a thematic analysis of the data, SSM was performed to understand the existing challenges, and develop a suitable model for improvement. The study found that SSM was a good tool for understanding the ‘messy’ circumstances surrounding the chosen construction project supply chain, as well as actions that could be taken to improve the supply chain’s efficiency on site. The findings add weight to the argument that SSM could be a good tool for project managers to systematically introduce into their project planning regimens

Some Recent Developments in Sewage Sludge Pumping

1988 ◽  
Vol 20 (4-5) ◽  
pp. 227-236
Author(s):  
J. H. Lohmann ◽  
W. F. Garber
Keyword(s):  
Sewage Sludge ◽  
Treatment Plant ◽  
Rheological Characteristics ◽  
Volatile Content ◽  
Collection System ◽  
Positive Displacement ◽  
Low Viscosity ◽  
Recent Developments ◽  
Cylinder Piston ◽  
Pumping Equipment

The pumping of sewage sludge solids is reviewed in terms of handling high and low viscosity materials with solids concentrations varying from about 4 % to perhaps 50 %. Knowledge of rheological characteristics including thixotropy is necessary in designing pumping systems with sludge solids percentages, volatile content, particle size, abrasives content and temperatures being variables which could change pump types found suitable from facility to facility. The characteristics of a sewage collection system is also important in determining pumping parameters needed in a treatment plant. Solids handling equipment from other industries have made significant contributions to sewage solids pumping in recent years. Included are moyno-type progressing cavity screw-centrifugal, recessed impeller rotation piston positive displacement, and two cylinder piston S-transfer positive displacement pumps. Pumping equipment used in the F.R.G. and in Southern California in the U.S.A. is remarkably similar. These types of pumps offer the possibility of designing optimum solids dewatering and transfer systems.

Analysis and design of suitable model structures for activated sludge tanks with circulating flow

1999 ◽  
Vol 39 (4) ◽  
pp. 55-60 ◽  
Author(s):  
J. Alex ◽  
R. Tschepetzki ◽  
U. Jumar ◽  
F. Obenaus ◽  
K.-H. Rosenwinkel
Keyword(s):  
Activated Sludge ◽  
Large Scale ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
High Sensitivity ◽  
Suitable Model ◽  
Model Structure ◽  
Analysis And Design ◽  
Hydraulic Behaviour ◽  
Model Structures

Activated sludge models are widely used for planning and optimisation of wastewater treatment plants and on line applications are under development to support the operation of complex treatment plants. A proper model is crucial for all of these applications. The task of parameter calibration is focused in several papers and applications. An essential precondition for this task is an appropriately defined model structure, which is often given much less attention. Different model structures for a large scale treatment plant with circulation flow are discussed in this paper. A more systematic method to derive a suitable model structure is applied to this case. Results of a numerical hydraulic model are used for this purpose. The importance of these efforts are proven by a high sensitivity of the simulation results with respect to the selection of the model structure and the hydraulic conditions. Finally it is shown, that model calibration was possible only by adjusting to the hydraulic behaviour and without any changes of biological parameters.

Rheological Characteristics and Methodology of Ice Cream: A Review

2020 ◽  
Vol 16 (5) ◽  
pp. 666-674
Author(s):  
Amir M. Mortazavian ◽  
Najme Kheynoor ◽  
Zahra Pilevar ◽  
Zhaleh Sheidaei ◽  
Samira Beikzadeh ◽  
...  
Keyword(s):  
Process Design ◽  
Flow Behavior ◽  
Ice Cream ◽  
Rheological Parameters ◽  
Rheological Characteristics ◽  
Rheological Analysis ◽  
Fundamental Information ◽  
Food Structure ◽  
Analytical Tools ◽  
Penetration Tests

The rheological analysis is important analytical tools used to obtain fundamental information about food structure. For instance, the properties of flow of liquid and semi-solidity are characterized by the consistency and flow behavior experiments as two important rheological parameters. The rheological parameters of foods are applied in quality control of the products and processing of food products such as energy input calculations, process design, equipment selection, and especially for deciding on heat exchangers and pumps. Steady flow behavior, oscillatory, and penetration tests are among commonly used parameters for evaluating rheological characteristics of ice cream. The purpose of this paper is to provide an overview of recent experiments and methods for measuring the rheological and texture properties of ice cream.

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