Longitudinal Change Behaviour

Keywords shrinkage, PCC, PCM, polymer modified, cement stone, adhesive bond, longitudinal change behaviour, shrinkage stress, porosity... 

Experiments on the longitudinal change behaviour of polymer-modified cement stones on the adhesive bond... 

In the experiments carried out so far, it was shown that the longitudinal change behaviour of mortars is negatively influenced by polymer modification. In order to draw conclusions what kind of effect this has as far as cohesion in the PCCs is concerned, model tests were carried out on stone samples which were coated on both sides with modified cement paste. In preliminary works before, the development of the dynamic E-modulus as well as of the tensile strength of the cement stones had been investigated. 

For some solid state samples, transverse relaxation may be very efficient, while longitudinal relaxation does not take place at a measurable rate. This behaviour is easily understandable if we take into account that direct interactions between the individual moments may lead to the loss of phase coherence (initially induced by Bj ) without any change in the energy of the spin system. Transverse relaxation does not necessarily require the presence of the lattice and the expression spin-spin relaxation frequently used in place of transverse relaxation illustrates this characteristic. Nevertheless, the term spin-spin relaxation can be criticized and the possibility of a transverse decay in the absence of any lattice has been questioned even in the solid phase (3, p. 29, and 4, p. 108). In the gas or the liquid phase, the loss of phase coherence is always mediated by the lattice and therefore the term spin-spin relaxation is confusing. 

In our research on low-level lead exposure we adopted a strategy of cross-sectional and longitudinal study of the intellectual, social, and neurobehavioural development of preschool children exposed to low or moderate blood lead (PbB) levels. We asked two questions (a) Does cross-sectional comparison show a significant interaction between age and PbB levels, between age and type of exposure (occupational versus non-occupational), or between age and the important behavioural covariates of lead exposure (SES level, maternal IQ, and quality of the caregiving environment) and (b) Upon regular 5-year re-evaluations, can changes in these children s intellectual, social, and neurobehavioural development be related to current PbB levels or to cumulative previous PbB levels after removal of lead from their home environment ... 

Frozen unconsolidated sediments (permafrost) show behaviour more comparable to consolidated sediments. Ice between grains acts like cement and the velocity of longitudinal and transverse waves is distinctly higher than in the non-frozen state. Some data from Canadian Arctic permafrost samples are shown in Table 6.8. Velocity changes in freezing temperatures are discussed also in Pandit and King (1979) and Scott et al. (1990). 

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