Grass determination

Defubed as the average absolute deviation of the four traction values from the mean. The range is determined by the type and condition of grass. ... 

The determination of citral in lemon-grass oil by the neutral sulphite absorption process ves results some 4 per cent, lower than those obtained by the bisulphite method, but the latter is that usually adopted in commerce, though, as alreadv stated, the former is official in the new Britiih Pharmacopmia. 

The Lotka-Volterra reaction described in Section 2.5.4 has three initial conditions—one each for grass, rabbits, and lynx—all of which must be positive. There are three rate constants assuming the supply of grass is not depleted. Use dimensionless variables to reduce the number of independent parameters to four. Pick values for these that lead to a sustained oscillation. Then, vary the parameter governing the grass supply and determine how this affects the period and amplitude of the solution. 

Chloroacetanilides are soil-applied herbicides used for pre- and early post-emergence control of annual grasses and broadleaf weeds in crops. Representative chloroacetanilide compounds, alachlor, acetochlor, and metolachlor, are extensively used worldwide. Other chloroacetanilides with limited usages include propachlor, bu-tachlor, metazachlor, pretilachlor, and thenylchlor. Public environmental concerns and government regulatory requirements continue to prompt the need for reliable methods to determine residues of these herbicides. There now exist a variety of analytical methods to determine residues of these compounds in crops, animal products, soil, and water. The chemical structures and major crops in which these compounds are used are summarized in Table 1. 

Residual pendimethalin in various crops was determined as follows." A 10-20-g amount of fruits or vegetables was extracted by blending twice with 200 mL of methanol. Grasses and mint were extracted with 200 mL of methanol-water (1 1, v/v). Nuts were extracted with 200 mL of n-hexane-2-propanol (3 1, v/v). For the residue analysis of the dinitroaniline herbicides butralin, dinitramine, ethalfluralin, pendimethalin, and trifluralin, a tomato sample (5 g) was extracted twice with 20 mL of methanol in a Sorvall homogenizer and filtered through filter paper. Benfluralin and trifluralin residues in the sample (10 g) were extracted with 100 mL of acetonitrile-water (99 1, v/v) in 250-mL screw-cap jars with Teflon liners rotated for 1 h on an end-over-end shaker (40 rpm). ... 

It is generally accepted that below 6°C grass is unlikely to grow, and this is known as the cardinal temperature. Alberda (1965) stated that at temperatures above 11 °C grass growth is independent of increase in temperature and that under optimal nutritional conditions growth is then determined by light intensity. 

To monitor the absorbed chlorpyrifos doses in human volunteers, urine was collected before and following a 4-hr activity period on the treated grass surface(re-entry). The urine was analyzed for 3,5,6-trichloropyridinol (3,5,6-TCP), the urinary metabolite of chlorpyrifos, and creatinine, which was determined to verify completeness of urine collection by each volunteer. 

The adult dermal dose resulting from contact of grass with hands was determined through a hand wash of each volunteer at the termination of the activity period. The dermal hand dose was estimated using ... 

From sedimentation and diffusion measurements, Ogston has determined the molecular weight of the fructans from both leafy cocksfoot grass (Dacty-lis glomerata) and Italian rye grass (Lolium italicum) to be 5,500.261 Both polysaccharides were polymolecular, and the data indicated a singly-branched structure for each. 

Aitken, MJ. (1990). Science-based Dating in Archaeology. Longman, London. Awadallah, R.M., Sherif, M.K., Amrallah, A.H. and Grass, F. (1986). Determination of trace elements of some Egyptian crops by instrumental neutron... 

Diclofop-methyl is an early post-emergence herbicide applied to cereals, oil seeds and a variety of other crops for the control of annual grasses. Both Diclofop-methyl and its hydrolysis product, diclofop, are herbicidal [200] therefore, analysis for Diclofop-methyl in soil includes the determination of both chemicals. 

Kimerle [27] reviewed the ecotoxicology of LAS focusing on the results rather than on the method of analysis, for which the author referred to the review undertaken by Painter and Zabel [30], alluding only to two papers on biota sample preparation. Litz et al. [31] determined the concentration of LAS in rye grass by Azure A active substances (AzAAS). AzAAS is a non-specific colorimetric method, which has not been used as frequently as MBAS (see Chapter 3.1). Briefly, it consists of the formation of an ion association complex with a dyed solution of Azure A (cationic). The complex formed is solvent-extractable and is separated from unreacted dye prior to colour measurement. 

Bowman MC, Beroza M. 1969. Rapid GLC method for determining residues for fenthion, disulfoton and phorate in corn, milk, grass and feces. J Assoc Off Anal Chem 52 1231-1239. 

Recommendation (Blue Grass) EH-1. Tetrytol should not be processed simultaneously with any lead-containing energetic material until such time as it can be confirmed that lead picrate will not precipitate from the hydrolysate. The solubility of lead picrate in the reaction medium should be determined as a function of temperature, and the lead in the reaction should be accounted for in a mass balance. 

Like other technology providers in the ACWA EDS program, PMACWA and Eco Logic determined what testing was required to ensure that its EDP for Blue Grass was completed to a level of detail necessary for proceeding to full-scale design and implementation. 

Samples of manure were collected from the farms during both experimental periods. The samples were used for nutrient content determinations and for a pot experiment in which Italian rye grass was cultivated. The nutrient contents obtained were compared with the values for the farm in question during the use of different litters, and with the grouped means for the different litter manures. 

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