Extractive Bulking

Consider the following example of a timber having an unextracted basic density of 530 kg m, comprising 500 kg m of wood and 30 kg m of hydrophilic (water-soluble) extractives deposited within the cell wall 

If it had been assumed that the wood was extractive-free then the estimated oven-dry volumetric shrinkage would be  

However, the extractive-free basic density of this wood is actually 500 kg m , so if it were not bulked by extractives it should only shrink by 15% on oven-drying and by 7.5% on drying to 15% moisture content. 

This wood has 30 kg of extractives in a cubic metre of green wood and, assuming a density of 1400 kg m for these extractives (Tarkow and Krueger, 1961), they will occupy 0.021 m of the swollen cell wall per m of swollen wood. If the extractives were not present, the extractive-free basic density would be 500 kg m and the wood would shrink by 15%, i.e. the cell wall would shrink by 0.15 m per m of swollen wood. However the water soluble extractives occupy 0.021 m of the cell wall for every m of swollen wood, so the wood and the cell wall can only shrink by 0.150-0.021 m, i.e. 0.129 m per m of swollen wood rather than by 0.150 m per m which would be expected of an extractive-free wood having a basic density of 500 kg m. The oven-dry volumetric shrinkage will be only 12.9% rather than 15.0%. 

If extractives were located in the lumens rather than in the cell walls this timber would shrink by 15% on oven-drying. However, the expected shrinkage for extractive-free wood of this density (530 kg m ) would be 15.9%. The estimated shrinkage on drying to 15% moisture content is 94% (7.5/7.95) of that predicted (7.95%) and the estimated fibre saturation point would be 28%. 

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Liquid-liquid extraction Bulk liquid membrane transport Liquid surfactant membrane transport... 

Adi pose ti ssue Extraction, bulk lipid removal, Florisil fracti onati on HRGC/MS 0.1 ng/g No data Mack and Stanley 1984... 

There are several different methods based on 16S rRNA sequences that can be used to study bacterial community structure. The first approach involves extracting bulk nucleic acids from samples and then using this material in subsequent molecular analyses. A large number of these methods involve the polymerase chain reaction (PCR). Using PCR, target gene sequences... 

Belladonna extract Bulk and tablets GC buffer pH 2.0 (3 2) Dissolve in acid USP-G3... 

Extracting Bulk Resistance from the Nyquist Plots.351... 

EXTRACTING BULK RESISTANCE FROM THE NYQUIST PLOTS... 

Bulk density Density of extract Bulk density of flooding point Packing/fllling material... 

As discussed in more detail elsewhere in this encyclopaedia, many optical spectroscopic methods have been developed over the last century for the characterization of bulk materials. In general, optical spectroscopies make use of the interaction of electromagnetic radiation with matter to extract molecular parameters from the substances being studied. The methods employed usually rely on the examination of the radiation absorbed. 

The mother liquors from the washings and recrystallisations are saved for the recovery of the 4-nitrophthalic acid. The combined mother liquors ore concentrated to a small bulk and the acid is extracted with ether. Upon esterification by the Fischer - Speier method, the 3-nitro acid forms only the acid ester and may be removed by shaking the product with sodium carbonate solution, whilst the neutral ester of 4-iiitrophthalic acid remains unaffected. Hydrolysis of the neutral ester gives the pure 4-nltrophthalio acid, m.p. 165°. 

The fusion of hydrogen into helium provides the energy of the hydrogen bomb. The helium content of the atmosphere is about 1 part in 200,000. While it is present in various radioactive minerals as a decay product, the bulk of the Free World s supply is obtained from wells in Texas, Oklahoma, and Kansas. The only known helium extraction plants, outside the United States, in 1984 were in Eastern Europe (Poland), the USSR, and a few in India. 

Earlier we described a voltammogram as the electrochemical equivalent of a spectrum in spectroscopy. In this section we consider how quantitative and qualitative information may be extracted from a voltammogram. Quantitative information is obtained by relating current to the concentration of analyte in the bulk solution. Qualitative information is obtained from the voltammogram by extracting the standard-state potential for the redox reaction. For simplicity we only consider voltammograms similar to that shown in Figure 11.33a. 

The reaction is initiated with nickel carbonyl. The feeds are adjusted to give the bulk of the carbonyl from carbon monoxide. The reaction takes place continuously in an agitated reactor with a Hquid recirculation loop. The reaction is mn at about atmospheric pressure and at about 40°C with an acetylene carbon monoxide mole ratio of 1.1 1 in the presence of 20% excess alcohol. The reactor effluent is washed with nickel chloride brine to remove excess alcohol and nickel salts and the brine—alcohol mixture is stripped to recover alcohol for recycle. The stripped brine is again used as extractant, but with a bleed stream returned to the nickel carbonyl conversion unit. The neutralized cmde monomer is purified by a series of continuous, low pressure distillations. 

In general, the foUowing steps can occur in an overall Hquid—soHd extraction process solvent transfer from the bulk of the solution to the surface of the soHd penetration or diffusion of the solvent into the pores of the soHd dissolution of the solvent into the solute solute diffusion to the surface of the particle and solute transfer to the bulk of the solution. The various fundamental mechanisms and processes involved in these steps make it impracticable or impossible to describe leaching by any rigorous theory. 

Any one of the five basic processes may be responsible for limiting the extraction rate. The rate of transfer of solvent from the bulk solution to the soHd surface and the rate into the soHd are usually rapid and are not rate-limiting steps, and the dissolution is usually so rapid that it has only a small effect on the overall rate. However, knowledge of dissolution rates is sparse and the mechanism may be different in each soHd (1). 

Lemon and Lime Juice. Lemons and Persian limes can be extracted using the same PMC and AMC extractors described above. The juice can be concentrated in a TASTE evaporator, an APV Crepaco, Inc. evaporator, or other types of evaporators (13). Although lime juice, and especially lemon juice, are widely used as condiments on food, the bulk of concentrated juice is used to make frozen concentrated lemonade and limeade. Prozen... 

Large-scale recovery of light oil was commercialized in England, Germany, and the United States toward the end of the nineteenth century (151). Industrial coal-tar production dates from the earliest operation of coal-gas faciUties. The principal bulk commodities derived from coal tar are wood-preserving oils, road tars, industrial pitches, and coke. Naphthalene is obtained from tar oils by crystallization, tar acids are derived by extraction of tar oils with caustic, and tar bases by extraction with sulfuric acid. Coal tars generally contain less than 1% benzene and toluene, and may contain up to 1% xylene. The total U.S. production of BTX from coke-oven operations is insignificant compared to petroleum product consumptions. 

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