Gas-Assisted Mechanical Extraction of Oil Seeds

2006 ◽  
Vol 78 (9) ◽  
pp. 1241-1242 ◽  
Author(s):  
N. J. M. Kuipers ◽  
M. J. Venter ◽  
P. Willems ◽  
A. B. de Haan
Keyword(s):  
Oil Seeds ◽  
Mechanical Extraction

Mechanical extraction of microfossils

1989 ◽  
Vol 4 ◽  
pp. 99-100 ◽  
Author(s):  
Jean M. Berdan
Keyword(s):  
Sewing Needle ◽  
Binocular Microscope ◽  
Calcareous Microfossils ◽  
Working Distance ◽  
Mechanical Extraction ◽  
Ordinary Steel

The described techniques for extraction of microfossils are directed primarily at the extraction of calcareous microfossils from various types of limestone, although the same techniques may beused for some sandstones and shales. The equipment needed is not complicated; the most obvious is a good binocular microscope with a working distance of three or more inches, to allow manipulation of the rock from which the specimens are to be extracted. The magnification required depends on the size of the specimens, but should go up to at least 80x. Other essential tools are a pin vise with a chuck which will hold an ordinary steel sewing needle and a rotary dental machine or other grinding device which will accept a small thin carborundum wheel. The latter is useful for sharpening needles as well as for cutting specimens out of the rock. An additional useful item is a percussive device such as a mechanical engraver fitted with a chuck which will hold an old fashioned steel phonograph needle. This instrument is described in detail by Palmer (this volume, chapter 20). A dish of water and a fine (00000) camel's hairbrush are necessary to move the specimens, once freed, to a slide or other receptacle. A rock trimmer is useful for reducing large blocks of fossiliferous rock into pieces that can be handled under the microscope, although with some collections this can be done with a hammer and cold chisel. Some paleontologists prefer to crush their samples and then pick through the chips to find specimens; however, this technique tends to break spines and frills from highly ornamented forms and is not recommended unless the microfauna is known to consist mostly of smooth species. Most of the equipment mentioned above can be found in catalogs such as that of the Edmund Scientific Co., 101 E. Gloucester Pike, Barrington, N.J. 08007.

The impact of mechanical ventilation operation strategies on indoor CO2 concentration and air exchange rates in residential buildings

2020 ◽  
pp. 1420326X2096076
Author(s):  
Pedro F. Pereira ◽  
Nuno M. M. Ramos
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Exchange Rates ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Ventilation Strategy ◽  
The Impact ◽  
Mechanical Extraction ◽  
Air Exchange

In Portugal, residential buildings commonly have their ventilation strategy changed after commissioning. This occurs due to the building managers' willingness to reduce shared costs with the electricity needed for fan operation. However, this option is not technically supported, and the effects of such a strategy on indoor air quality-related to human pollutants are yet to be quantified. CO2 was monitored in 15 bedrooms and air exchange rates were calculated for each room. The air exchange rate values ranged from 0.18 to 0.53 h−1 when mechanical extraction ventilation was off, and from 0.45 to 0.90 h−1 when mechanical extraction ventilation was on, which represents an average increase of 119%. With the current intermittent ventilation strategy, all rooms remain above 1500 ppm for a given percentage of time, and 12 rooms presenting CO2 concentrations above 2000 ppm. Simulations of theoretical CO2 concentrations, for a non-interrupted mechanical ventilation strategy show that no rooms would accumulate CO2 concentrations above 2000 ppm, and only 25% would present CO2 concentrations above 1500 ppm. Pearson correlations between the monitored CO2 and human and spatial factors identified two relevant parameters. Those parameters correspond to ratios between CO2 generation and floor area ([Formula: see text]), and airflow with CO2 generation ([Formula: see text]). The proposed ratios could be used as ways to optimise ventilation costs and indoor air quality.

scholarly journals Kinetic and regulatory properties of cytosolic pyruvate kinase from germinating castor oil seeds

1991 ◽  
Vol 279 (2) ◽  
pp. 495-501 ◽  
Author(s):  
F E Podestá ◽  
W C Plaxton
Keyword(s):  
Pyruvate Kinase ◽  
Castor Oil ◽  
Mixed Type ◽  
Competitive Inhibition ◽  
Ricinus Communis ◽  
Cytosolic Ph ◽  
Oil Seeds ◽  
Saturation Kinetics ◽  
Regulatory Properties

The kinetic and regulatory properties of cytosolic pyruvate kinase (PKc) isolated from endosperm of germinating castor oil seeds (Ricinus communis L.) have been studied. Optimal efficiency in substrate utilization (in terms of Vmax/Km for phosphoenolpyruvate or ADP) occurred between pH 6.7 and 7.4. Enzyme activity was absolutely dependent on the presence of a bivalent and a univalent metal cation, with Mg2+ and K+ fulfilling this requirement. Mg2+ binding showed positive and negative co-operativity at pH 6.5 (h = 1.6) and pH 7.2 (h = 0.69) respectively. Hyperbolic saturation kinetics were observed with phosphoenolpyruvate (PEP) and K+, whereas ADP acted as a mixed-type inhibitor over 1 mM. Glycerol (10%, v/v) increased the S0.5(ADP) 2.3-fold and altered the pattern of nucleotide binding from hyperbolic (h = 1.0) to sigmoidal (h = 1.79) without modifying PEP saturation kinetics. No activators were identified. ATP, AMP, isocitrate, 2-oxoglutarate, malate, 2-phosphoglycerate, 2,3-bisphosphoglycerate, 3-phosphoglycerate, glycerol 3-phosphate and phosphoglycolate were the most effective inhibitors. These metabolites yielded additive inhibition when tested in pairs. ATP and 3-phosphoglycerate were mixed-type inhibitors with respect to PEP, whereas competitive inhibition was observed for other inhibitors. Inhibition by malate, 2-oxoglutarate, phosphorylated triose sugars or phosphoglycolate was far more pronounced at pH 7.2 than at pH 6.5. Although 32P-labelling studies revealed that extensive phosphorylation in vivo of soluble endosperm proteins occurred between days 3 and 5 of seed germination, no alteration in the 32P-labelling pattern of 5-day-germinated endosperm was observed after 30 min of anaerobiosis. Moreover, no evidence was obtained that PKc was a phosphoprotein in aerobic or anoxic endosperms. It is proposed that endosperm PKc activity of germinating castor seeds is enhanced after anaerobiosis through concerted decreases in ATP levels, cytosolic pH and concentrations of several key inhibitors.

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