A Model for Automatic Control of Vibratory Plate Compactor
of the most Application of automatic control into compaction eglenineering works. This isoduel to problem compared with other machines used in civil g the difficulties in getting proper feedback, consisting of a transfer to the compactor and information on the state of the soil being just under compaction. The The paper presents an approach to this difficult and practically ti p ort nt p h have been discussion contains evaluation of several different responses possibility of a1 in information on g used so far in compaction analysis. compactor without Additionally, involving mathematical model of soil is mechanical behaviour of c pacto considered.
Dynamic Compaction Analysis
A simplified model based on the one‐dimensional wave equation, which accounts for the interaction of the pounder and the soil, and the propagation of stress wave in the soil during the dynamic compaction of loose granular soil is presented. The soil beneath the pounder is represented by a nonlinear soil column, while the surrounding soil is represented by a series of springs and dashpots. The spring simulates the dynamic soil stiffness and the dashpot accounts for the radiation damping effect. The input soil parameters of the model can be determined in the laboratory or estimated from correlations with measured field data. In spite of the various simplifying assumptions in the model and the predictive method, computed results, such as pounder penetration and degree and depth of improvement, show an encouraging measure of agreement with available field measurements from two dynamic compaction projects. The proposed model is potentially useful for the analysis of dynamic compaction of loose granular soil.
Formation of unexpected ions from a first-generation polyamidoamine dendrimer by use of methanol: an artefact due to electrospray emitter corrosion?
We report the formation of unexpected ions during the analyses of a first-generation polyamidoamine dendrimer in negative ion mode using an ion trap equipped with an electrospray ionisation source. These surprising ions corresponded to an increase of 12 m/z units over those expected. The formation of the unexpected ions was dependent on the tuning of the solution flow rate and the capillary high voltage. In addition, measurements of unusual value of the current suggested that a reaction was occurring in the corona plasma. The influence of methanol in this phenomenon was demonstrated by using CD(3)OH in the sample preparation. We propose two structures to explain the observed adduct based on the results of MS(2) experiments and by referring to previous work dealing with 12 m/z units addition. We showed that a corona discharge caused by alterations taking place to the electrospray capillary emitter was the origin of these unexpected ions. Finally, we discuss the mechanism involved in the formation of the ions and we propose means to control such artefacts.