An X-ray CT study of miniature clay sample preparation techniques

Abstract

The quality and reliability of cohesive soil laboratory test data can be significantlyaffected by sample disturbance during sampling or sample preparation. Sample disturbance may affect key design and modelling parameters such as stiffness, preconsolidation stress, compressibility and undrained shear strength, and ultimately determine particle mobilization and shear plane development. The use of X-ray computed tomography (X-CT) in the study of soil is restricted by the inverse relationship of specimen size and obtainable image resolution. This has led to the testing of miniature specimen sizes which are far less than conventional laboratory sample size in a bid to obtain high resolution images and detailed particle-scale soil properties; however, these miniature soil specimens are more prone to sample disturbance. In this work 2% muscovite was mixed with speswhite kaolin clay as a strain marker for use in X-CT. The clay soil sample was prepared from slurry and either consolidated using an oedometer or a gypsum mould. Specimens obtained from a 7 mm tube sampler were compared to lathe trimmed specimens with a diameter (Ø) of 7 mm. Results from X-CT imaging were used to study the influence of sampler type on specimen disturbance, by analysing the muscovite particle orientation of the obtained 3D images. The results show that; for samples subjected to large consolidation stress (>200kpa) lathe trimmed specimens may be subject to lesser disturbance compared to tube sampled specimens.

Flexible gypsum mould applied in the mechanical system for blank of grouted ceramic handicrafts based on the radial movement of the sphere and connection by the principle of six‐point positioning

“…Then the arm connector starts upward movement. When the position sensor (2) 593 hints that the arm connector vertical movement is in place, the vertical motion stops. The electromagnet 56 is off, push rod returns, and compression spring 54 stretches, driving the flexible working edge of the manipulator arm connector rotate around the hinge from the β angle position to the α angular position, meanwhile the working edge of the manipulator arm connector 59 contacts and then offsets tightly with the working plate (2) 51 of the side die piece.…”

“…The ingredients for the gypsum mould were decided upon, and an additional compression with a vibration process was introduced to enhance the mechanical strength of the gypsum mould. Christopher Ibeh et al [2] put forward an X‐ray CT study of miniature clay sample preparation techniques; the clay soil sample was prepared from slurry and either consolidated using an oedometer or a gypsum mould for improvement of the sample. Blazutti Marçal et al [3, 4] aimed to present slip casting as a processing route for producing hydroxyapatite struts, and show the thermal phase stability, with gypsum mould.…”

“…is side die of gypsum mould; working plate of the connector of side die for gypsum mould (2); 52 is composite material layer (1); 53 is composite material layer (2); 54 is compression spring; 55 is robot arms (manipulator arm); 551 is position sensor (1); 56 is electromagnet; 57 is the push rod; 58 is steel ball; 59 is spring working edge of robot arm connector; 591 is cylinder pin; 592 is cylinder pin sleeve; 593 is position sensor(2) …”