Laboratory Screening Experiments

With real biomass and wastes, only batch experiments have been done in our laboratory up to now. Table 3 shows results of the screening experiments with straw, wood and sewage sludge at temperatures of 450 and 500 C using the tumbling autoclave,... 

Sometimes, the effect of a factor can only be presumed and its effect would have to be assured by suitable screening experiments. Because of the complexity of most of the analytical problems, there will be additional factors that are either unknown or cannot be controlled by the experimenter. Uncontrolled factors might be the impurity of reagents, intoxication of an electrode surface, the instability of a plasma source, and the changing quality of a laboratory assistant s work. 

Batch polymerisations are often performed in screening experiments on the laboratory-scale level. However, batch polymerisations are used less often in large-scale, commercial produchon processes than semi-continuous polymerisations because of the inherent limitations in heat transfer and copolymer composition control. 

The results of more than 15 years of screening experience in the author s laboratory has shown that the best short cut to finding in vivo effective immunostimulants are investigations using experimental animals and infectious stress or immunosup-... 

A regularly formed crystal of reasonable size (typically >500 pm in each dimension) is required for X-ray diffraction. Samples of pure protein are screened against a matrix of buffers, additives, or precipitants for conditions under which they form crystals. This can require many thousands of trials and has benefited from increased automation over the past five years. Most large crystallographic laboratories now have robotics systems, and the most sophisticated also automate the visualization of the crystallization experiments, to monitor the appearance of crystalline material. Such developments [e.g., Ref. 1] are adding computer visualization and pattern recognition to the informatics requirements. 

Wheat straw was obtained from Silsoe Research Institute (Silsoe, Bedfordshire, UK), and was dried in a cabinet oven with air circulation at bO C for 16 h. The dried wheat straw was then ground using a Christie Laboratory mill to pass a 60-mesh size screen and stored at 5°C until use. All chemicals were of analytical or regent grade. All experiments were performed in duplicate and yield is given on a dry wheat straw weight basis. 

Another compartmental partitioning issue of major consequence for pesticides is the dissolved versus adsorbed fraction in an aqueous environment. Carter and Suffet (16) present measurements of binding of pesticides to dissolved fulvic acids that-will provide inputs to compartment models. Data from laboratory measurements used in compartment models can often bypass costly field experiments in the screening stage. Thomas, Spillner and Takahashi (1 7) have related the soil mobility of alachlor, butylate and metachlor to physicochemical properties of these compounds. 

Also, other dependent variables associated with CO2-foam mobility measurements, such as surfactant concentrations and C02 foam fractions have been investigated as well. The surfactants incorporated in this experiment were carefully chosen from the information obtained during the surfactant screening test which was developed in the laboratory. In addition to the mobility measurements, the dynamic adsorption experiment was performed with Baker dolomite. The amount of surfactant adsorbed per gram of rock and the chromatographic time delay factor were studied as a function of surfactant concentration at different flow rates. 

In 1984 our two laboratories began to develop a multiple screen technique for making amount and size measurements on 218Po. The work proceeded independently at first, leading to different configurations of screens. Increasingly, the value of collaboration became apparent and this led to a one-week collaborative experiment at the BOM laboratory, September 23-27, 1985. This paper covers essentially all of our work on screens to date. 

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